Nominal dimensions of rollers.
\r\n\tDNA is responsible for carrying all the information an organism needs to survive, grow and reproduce. However, during its lifetime an each organism experiences a wide range of cases with DNA damages; therefore the DNA repair ability of a cell is vital to the integrity of its genome and thus to the normal functionality of that organism. Mutagenesis is known as an important factor which may lead to different disorders, disabilities and diseases. Any defect in DNA repair system may lead to the death of the organism.
\r\n\r\n\t
\r\n\tRecognition of these items in different organisms drives us to know more about the characteristics of DNA repair systems in different types of organisms. Hopefully, this book will offer an interesting read by introducing, explaining and comparing these diversities.
Cam mechanisms are one of the basic objects in the design of production machines and equipment, whose characteristic feature is a high degree of automation and optimization of production and work processes. These mechanical systems are characterized by the transmission of large load possibility at high speed and positional accuracy of the working member of the relevant machinery. Their application is mainly connected with the so-called hard automation, which is characterized by unchangeable or difficult to change operations of the given technical equipment. Their widespread use is known in manufacturing and handling machines of the manufacturing industry, with their dynamic effects and properties greatly affecting the overall behavior, operation, and efficiency of such machinery. At present, increasing demands are placed on the performance parameters of such machinery. Therefore, the operating speeds and thus the inertial effects of the moving bodies are increased, thereby reducing the usable operating frequency of the machines. These facts cause greater wear and reduce overall machine lifetime and reliability and must be taken into account when designing and developing them. The development of computer technology, numerical mathematics, and informatics enables the use of analytical and numerical methods in the design, development, and construction of cam mechanisms.
\nA general cam mechanism is typically referred to as a three-link mechanism with a single degree of freedom, which consists of two moving members mounted on a fixed frame (1). The moving members are the cam (2) and the follower (3) (see an example of a cam mechanism in Figure 1). In the case of the general cam mechanism, the general kinematic pair is formed of the contact of the working surfaces of the cam and the follower. The contact strain of the surface of the contact areas of the said type of kinematic pair, and in the vicinity of this surface, has a periodic course. As a result of the contact strain action, fatigue damage can occur on the contact surfaces. One of the criteria for such damage may be a value of the largest compressive principal stress in the contact area and in its vicinity. This is subsequently brought into the relationship with the strength limit of the respective material. The lifetime of the cam mechanisms is closely related to the choice of materials and their physical and mechanical properties from which the individual components are made, the method of material processing, and the technology of manufacturing of the individual parts or the way and the intensity of loading. It is connected with the way, intensity, and conditions of loading too. This issue connects the knowledge of theoretical, applied, and contact mechanics, tribology, material engineering, and structural analysis, though this theoretical knowledge must be supported by results from experimental identification.
\nA conjugate cam mechanism with an oscillating roller follower.
In technical practice, multi-body cam systems are often encountered in addition to the basic three-body cam systems, which may also contain transforming linkages and mechanisms with constant gear ratio. Such mechanical systems are termed cam hinge or also combined cam mechanisms. These mechanical systems with a single degree of freedom are characterized by a uniform motion of the driving member, which generally does not need to be a cam, in most of their applications. The shape of the working surface of the cam realizes the working motion of the working member of the system, which is not necessarily a follower. In many cases, the kinetostatic analysis method is sufficient for the basic determination of the time course of the dynamic behavior of these mechanical systems. The kinetostatic solution determines the driving force effects, reactions in joints, and the force effects transmitted by the cam mechanism and linkages. For the solution, the knowledge is necessary of the kinematic quantities and geometrical mass parameters of all members of the mechanism as well as action force effects acting on individual bodies. The results of kinetostatic analysis thus become the basic data for determining the distribution of contact stress in the contact area of the cam and follower.
\nThis section gives only basic information on how to solve the tasks of combined cam mechanisms. Fundamental terms and methods of analysis for the investigation of this type of the mechanical systems are specified. For example, the results of the kinematic analysis and synthesis are further used in kinetostatic or dynamic analysis tasks of these mechanical systems. The main goal of these analyses is to determine the courses of reactions in kinematic pairs, force loading of the cam and the follower, force effects acting on individual members, driving effects needed in the systems’ movement, etc. Knowledge of the acting forces in the cam mechanism general kinematic pair is significant to determine the contact stress distribution in the contact of the cam and the follower.
\nDetailed knowledge of this issue may be found in [1, 2].
\nBy definition, a general cam mechanism refers to a three-link mechanical system with a single degree of freedom that contains at least one cam linked with other members by means of at least one general kinematic pair. In this case, the general kinematic pair is formed by contacting the cam and the follower, whose movement is translation, rotation, or general. The cam mechanisms can implement a required working motion within a very precisely prescribed path with the use of a small number of bodies housed inside a relatively small space. The cam is the driving (or also input) member; in terms of shape, it is possible to define the basic cam types: radial, axial (cylindrical), and globoid. The follower is termed as the driven (or output or also working) member of a cam mechanism, which carries out the desired motion. The translating follower motion is defined as a translational or a general. The rotating follower, which performs a rotational motion, is usually called the lever. In order to reduce the passive resistance, the follower is often equipped with a roller in technical practice, whereby pure rolling in the interaction between the cam profile and the follower occurs, as is shown in Figure 1. This arrangement does not influence on the required follower motion.
\nOne of the main conditions for proper operation of the cam mechanism is to maintain permanent contact of the follower with the cam during the action. This constraint of a general kinematic pair is achieved by a load or a redundant kinematic constraint. In the first case, the given contact is held using preloaded returnable compression springs, gravity forces, or inbuilt hydraulic or pneumatic elements. The disadvantage of this arrangement is the increased force loading and wear of the cam mechanism, which is caused by the preload required for the permanent contact between the follower and the cam. In the second case, contact by the redundant constraint is ensured by adding an extra linkage. For example, a grooved cam can realize such an arrangement. This embodiment is simple, but its disadvantage is the change in the rotation direction of the roller in the cam groove during the relative movement between the roller follower and the cam. This phenomenon is caused by a change in the sense of the transmitted normal reaction between the roller and the cam groove, because the pole of relative motion changes during the cam mechanism operation. As a result, the working surfaces of the groove are more worn in the points of the change in the roller rotation. Dual cam and roller follower systems are a more preferred design of the cam mechanism with the redundant kinematic constraint, although this solution is more expensive and complicated to manufacture. The conjugate, complementary, or double-disc cam is one including dual radial discs, each in contact with at least two driven followers coupled by a rigid or a kinematic linkage. The mobility of this mechanism is ensured by a special dimension arrangement, where the actions of both working surfaces of the dual cam must correspond exactly to each other. A schematic representation of a cam mechanism with radial conjugate cams and an oscillating dual roller follower is shown in Figure 1. The given constraint consists of another radial cam II and a roller follower II.
\nThe shape of a cam contour is determined by the synthesis which is on the basis of the knowledge of the displacement law of the given cam mechanism and its dimensional parameters. The position of the cam relative to the frame of the cam mechanism is determined with an angular variable \n
As a combined cam mechanism, it is generally called a mechanical system usually with a single degree of freedom which includes at least one general cam mechanism. This system usually also includes sets of various transforming linkages with not only a constant but also a generally variable gear ratio. They are most often complemented by simple linkages with lower kinematic pairs. In practice, lower pairs are generally planar couplings between two movable adjusted neighboring members. The members connected by a kinematic pair with the frame are referred to as the basic members of the transforming linkages. They perform rotational or translational motion. The basic representatives of such mechanisms are four-bar mechanism, crank mechanism, oscillating mechanisms, gears, etc. (see examples in Figure 2). The following findings are presented in accordance with the knowledge in publication [1, 3, 4]:
\nSome common types of transforming linkages.
The input of the relevant linkage is an ordered triple of variables \n
By differentiating Eq. (1) in time, a relation may be obtained between the velocity and the acceleration:
\nDifferentiation with respect to time is denoted by dots in Eq. (2). The linkage ratio is called a magnitude, which is dependent on the position of the linkage, and it is given by Eq. (3):
\nThe derivatives of Eq. (3) with respect to positions are given by Eq. (4):
\nIntroducing Eqs. (3) and (4) into Eq. (2) gives:
\nwhich expresses relations for calculating the velocity and the acceleration of the output member.
\nThe individual linkage can be placed into so-called chains when the outputs of the given mechanism are also the inputs of the next mechanism. The algorithms of linkage solving are marked with transformation blocks \n
A chain of transformation blocks of linkages.
In relation to solving the problems with the combined cam mechanisms, we have introduced the following nomenclature (designation) of positional and kinematic magnitudes of the main members. Variable \n
The input chain \n
The output chain \n
The parallel chain \n
Block diagrams of the computation of combined cam mechanisms.
Indexes i, j, k, and l denote the ith, jth, kth, and lth linkage of the relevant chain.
\nThe calculation of the positional and kinematic quantities of any member of a combined cam mechanism is designed as a kinematic analysis (see the block diagram in Figure 4). The input data are typical data (geometrical mass quantity and dimensions) on a mechanism, the procedure of computation of its chains, displacement function \n
The shape of a cam contour is determined by the synthesis which is on the basis of the knowledge of a displacement law of the given combined cam mechanism and its dimensional parameters. The following observations on the displacement laws are presented in accordance with the knowledge in publication [1].
\nA function assigning time \n
An example of a displacement law.
The initial point \n
Derivatives of the unity displacement to \n
For the solution of problems related to the kinematic analysis and synthesis of cam systems, it is possible to use a broad set of displacement laws in a normalized form. These include, for example, polynomial, trigonometric, and exponential displacements and cycloidal, parabolic, and goniometric displacements (see [1]).
\nThe choice of displacement law greatly has an influence over the dynamic properties and behavior of high-speed mechanical systems, and it should meet the following basic criteria within the specified conditions:
In relation to the desired motion of the mechanism, the acceleration inertia forces, momentum, and performance of the cam mechanism should be always as small as possible.
The vibrations forced by the movement of the mechanical system should be kept at a minimum.
Both criteria lead to low dynamic strain on the members of the mechanical system due to dynamic effects. In addition, the second criterion is related to the accuracy of adherence to the prescribed working member positions and the elimination of any noise sources. Comprehensive and detailed information on the issues of the displacement law choice is provided in [1].
\nIn this text section, we will focus mainly on the general kinematic pair formed by contact of a cam and a roller follower. The mentioned type of kinematic constraint in the technical practice is usually most often constituted by a cylindrical roller and a cam or a crowned roller and a cam. In terms of computational purposes, we can substitute both mentioned contacts for the contact of cylindrical bodies with parallel axes and the contact of an elliptical body with a cylindrical one.
\nThe contact area of the general kinematic pair is subjected to cyclic loading within the working cycle, while the contact surfaces are primarily in rolling contact in combination with a small percentage of mutual sliding. Thus, the transmission of normal and tangential forces is realized. These phenomena cause deformation of both bodies in the contact and cause contact stress in them. The state of stress on the working surfaces and under it is characterized by the principal stresses, which are transient and have the character of pulses with a period of 2π. Fatigue damage of the cam and follower contact surfaces may occur after a certain number of cycles in the operation of cam mechanisms, as long as a certain limit value of this stress is exceeded at any point of the contact area. This damage is in the form of cavities (pitting), which develop from cracks on the working surface. For cams with a hardened surface, this layer can be broken and then peels off (spalling) (see Figure 6). Both types of damage occur due to the contact stress that can be described by the theory of contact mechanics (see [5]). In terms of estimating the lifetime of the contact areas of the general kinematic pair, the distribution of the reduced stress in the surface areas and at a certain depth under it is therefore an important criterion. Thus, in the area of cam mechanisms, it is primarily a matter of determining the service life of the cam and follower contact surfaces depending on the conditions of their force loading.
\nSome common types of fatigue damages of cams and rollers.
The state of deformation and stress existing between the two elastic bodies in contact under load can be established both based on the contact mechanics and based on the use of the finite element method (FEM). The contact mechanics deals with the study of stress and deformation of solids being in contact at one point or along a line, acting under normal and also tangential forces. Physical and mathematical relationships are formulated on the basis of knowledge of continuum mechanics as well as mechanics of materials with the focus on elastic, viscoelastic, and plastic bodies in static or dynamic contact. The principles of contact mechanics are used to solve the problems of contact of rolling bodies (balls, rollers, barrels, needles, tapered rollers) and roller bearing rings, the contact of teeth in gearings, the contact of railway wheels and rails, mechanical constraints, and, last but not least, the contact of the cam and cam follower. The result of the calculations is also Hertzian contact stress, where there is local stress in the contact area, being caused by the contact of two curved areas, whereas these are slightly deformed due to the acting load. Hertzian contact stress is a fundamental quantity in formulating the equations for determining the carrying capacity and fatigue lifetime of cam mechanisms, bearings, gearings, and all objects in general, whose surfaces are in contact. Comprehensive and detailed information on the issues of contact mechanics is provided in [5].
\nWhen two three-dimensional bodies are brought into contact, they touch initially at a single point (contact of the convex crowned roller with the cam) or along a line (contact of the cylindrical roller with the cam). Under the action of the slightest load \n
The contact of two nonconforming bodies after elastic deformation.
where \n
Point contact.
where \n
where \n
The contact stress is highly concentrated in the vicinity of the contact area and decreases rapidly with an increasing distance from it. Thus, the stress area is close to the body contact. Since the contact surfaces are dimensionally small compared to the rest of the bodies, the stresses around the contact area are not too much dependent neither on the shape of the bodies in the contact nor on the way of mounting the bodies. This hypothesis simplifies the definition of boundary conditions and allows applying the theory of elasticity of large bodies.
\nIn the case of the contact of the convex crowned roller with the cam and the cylindrical roller with the cam, it is clear that the abovementioned assumptions are satisfied. Thus, the results of Hertzian contact stress theory can be used to determine the stress state in their contact areas and at a certain depth under the surface (see [5]) or to use the results related to these contact types being given in publications [3, 6, 7], or we can directly calculate the contact stress for point or line contact by using the computational algorithms available on the webpage [8]. In Figure 8, there is a schematic presentation of the contact of the convex crowned roller and the cam (left) and distribution of the contact stress in the contact area (right). A similar case is shown in Figure 9 with the only difference that there is the contact of the cylindrical roller and the cam. The stress state is in these cases expressed by principal stresses \n
Line contact.
The stress state in a symmetry plane \n\nxz\n\n.
Another possible way of determining the stress in the contact areas of bodies is to use the finite element method. To achieve the relevant results, a dense finite element mesh in the contact area is required. This requirement leads to a large number of solved linear algebraic equations. The computational body contact algorithm is based on a numerical iteration of finding the elements in contact, so the numerical solution of the equations of the assignment takes place in several steps.
\nIn order to estimate the lifetime of the contact areas, it is first necessary to determine the magnitude of the reduced stress \n
The principal stress components \n
In the case of general kinematic pairs, the contact load on the contact surface of the bodies and under it has the periodic course. At the contact areas of the general kinematic pair and below these points, contact stress becomes a periodical magnitude related to the angular cam displacement \n
and its amplitude by the equation:
\nIn Eqs. (13) and (14), the variable \n
where variable \n
Conditional inequality Eq. (16) describes the fact that during the operation of the cam mechanisms, no destructive action of elastic deformation occur in the general kinematic pair.
\nThe criterion of damage of the loaded contact areas of the cam and the follower in cam mechanisms is the formation of cracks and cavities, so-called pitting. The problem of the pitting formation on the surfaces of the bodies in contact is with that the initiation and propagation of cracks in the loaded material is completely unpredictable because the crack nuclei that form are distributed randomly in the material. Such crack nuclei are inclusions in material or surface irregularity caused by the production and treatment of this material. Therefore, it is difficult to predict exactly the stress state at the point of the contact area in which the damage occurs due to the load. This problem can be solved by introducing a criterion whereby the value of the highest principal compressive stress is determined in the contact area of the bodies, and this is brought into relation with the ultimate strength of the respective material. In the case of pure rolling contact, its magnitude is equal to the maximum value of the contact pressure—Hertzian pressure \n
In the previous part of the article, we briefly discussed ways of determining the stress in the surface and subsurface parts of the contact areas of the bodies. The following text will mention two theoretical approaches, one of which is presented in [1] and the other in [2]. Both procedures result from the knowledge of the contact mechanics, and based on this, the Hertzian pressure value pH in the body contact area has been determined. Both methods require further the knowledge of some or several parameters that characterize the material from which the cam is made. These characteristic parameters are not available for all materials; therefore it is necessary to use experimental procedures. Not all materials are available for these materials, so further experimental procedures are required.
\nIn the course of the operation cycle of the cam mechanism, no damage caused by the formation of pits is acceptable on the contact surface under load. Referring to [1], such fatigue damage will not occur if Hertzian pressure is given by the Niemann empirical relation in the form:
\nwhere the variable \n
This criterion Eq. (18) is very simple because it is dependent on the only material parameter \n
Based on conclusions introduced in [2], a condition for the level of stress can be derived, in which the contact surface of the body will not be damaged:
\nin which the constant \n
Both conditions according to relations Eqs. (17) and (19) are illustrated graphically for selected steel \n
Load-life relationships for steel C22.
The geometrical shape of the roller crown itself has a significant effect on the stress distribution, due to the load and inertia effects in the contact areas of the general kinematic pair, which is usually formed in practice by a cylindrical roller and a cam or a crowned roller and a cam (see Figure 12).
\nSome types of roller profiles in contact with a cam.
It has been proven that the contact stresses in the vicinity of the shape, discontinuities in the contact area of the bodies in contact, are considerably higher than those reached outside the area of their immediate influence as described in the publication [2]. For this reason, the contact surfaces are more stressed, and their fatigue lifetime is reduced.
\nIn general, we can expect to achieve a longer lifetime of the general kinematic pair of any cam mechanism by using the cylindrical profile of the roller crown. However, in the case of a conventional straight roller, there are discontinuities at the intersection of the roller cylindrical profile with the cam profile. These are caused by the fact that one contact area is axially shorter than the other and also by chamfering the roller edges. In the vicinity of those profile discontinuities, the contact between the roller and cam cannot be considered as simply a straight line contact but for a more complex three-dimensional contact type. Therefore, in this case, it is not possible to apply the conclusions of Hertz’s theory of contact to the calculation of the contact stress distribution. These discontinuities cause a high concentration of contact pressure at the appropriate point in the contact area. In fact, these local increases in the distribution of contact pressure can exceed the strength limit of the given material and thus cause plastic deformation in the contact area, the formation of residual stresses in the material, or hardening of steel. The area in question will further be more prone to fatigue damage to the contact surfaces such as pitting or spalling.
\nTo ensure a more even distribution of contact stress in the contact area of the roller and cam, it is necessary to modify the shape of the axial cross-section of the roller crown. This is one of the reasons for the practical application of crowned rollers, when the radius of curvature of the crown profile is far greater than the radial radius of the roller (see Figure 12). Furthermore, we can easily compensate with their use misalignment between the roller and cam, without causing a fundamental change in the contact stress distribution. However, the largest concentration of contact stress distribution is achieved in the middle of the contact area with all the consequences as in the case of the straight roller.
\nThe reduction of excessive contact stress in the vicinity of straight roller edges is achieved by such a shape of the axial cross-section of the crown, which includes straight line and tangent circular arcs that are connected to it on each side (see Figure 12). However, this shape of the roller crown leads to a certain concentration of contact stress in the transition from the cylindrical segment of the roller to the crowned one. Uniform distribution of stress for different levels of loading of the general kinematic pair contact areas is achieved by the logarithmic profile of the roller crown (see [11, 12]).This type of the roller crown is characterized by a monotonously decreasing profile from its center to the edge according to the logarithmic function (see Figure 12).
\nThese facts will be demonstrated on examples of cam contacts with a cylindrical, crowned, and part-crown roller, which were defined using the finite element method (see [3, 13]). The formation of the model of a general kinematic pair using the finite element method is based on assumptions on the basis of which Hertz’s theory of contact of two elastic bodies is derived (see [5]). The main assumption is that the contact area is continuous and much smaller than the characteristic dimensions of the bodies in contact. Therefore, the stresses in the vicinity of the contact area are not so dependent on the shape of the bodies in contact nor on how these bodies are fixed. Furthermore, it is assumed that the contact stress is very concentrated in the vicinity of the contact region and rapidly decreases with an increasing distance from it. The region of stress acting is therefore in the vicinity of the contact of the bodies. Through these basic assumptions, the definition of boundary conditions is simplified, and the application of the theory of elasticity of large bodies with sufficiently small deformations is allowed.
\nWhen creating a finite element model of a general kinematic pair of a cam mechanism, the contact of the roller with the cam will be replaced by the contact of two segments of solids of revolution. One of the solids of revolution represents the roller with the desired forming profile, and the other with a cylindrical profile replaces the cam. The radius of the cylinder is identical to the radius of curvature of the cam at the point of its contact with the roller. For the purposes of the computational analysis, we will use one eighth of each of them, assuming the parallelism of the axes of both replacement solids (see Figure 13). In the \n
A schematic drawing of a roller in contact with a cam.
To achieve the relevant results, it is important that a uniform and dense finite element mesh be used to the discretization of the contact area and its vicinity of both bodies. The size of the elements can gradually increase with an increasing distance from the contact areas. For example, the size and shape of the contact area can be predicted by calculating based on Hertz’s contact theory applied to contact of cylindrical bodies with parallel axes or to contact of a body with general profile and cylindrical body. Using this theory, we calculate the components of deformations and stresses in the contact area and its vicinity of both bodies in contact. Furthermore, the shape and size of the contact region are determined depending on the load size. This issue has been dealt with in articles [3, 6, 7] or is published in detail in [5]. Then, on the basis of the data thus determined, we define the space to create an acceptable finite element mesh density of the analyzed bodies with respect to the corresponding results compared to the real state.
\nThe application of the above procedure will be demonstrated on the analysis of the contact stress distribution in the contact area of the cam, of which nominal dimensions are the width \n
\n | Straight roller | \nCrowned roller | \nPart-crown roller | \n|
---|---|---|---|---|
Nominal diameter | \n\n\n | \n35.0 | \n35.0 | \n35.0 | \n
Effective width | \n\n\n | \n18.0 | \n18.0 | \n18.0 | \n
Fillet radius | \n\n\n | \n0.6 | \n0.6 | \n0.6 | \n
Crown radius | \n\n\n | \n— | \n500 | \n200 | \n
Crown width | \n\n\n | \n— | \n— | \n6.0 | \n
Nominal dimensions of rollers.
\n | Roller: 100Cr6 | \nCam: 16MnCr2 | \n|
---|---|---|---|
Young’s modulus of elasticity | \n\n\n | \n210 | \n206 | \n
Shear modulus | \n\n\n | \n81 | \n79 | \n
Poisson’s ratio | \n\n\n | \n0.3 | \n0.3038 | \n
Material characteristics of steels.
Significant results are summarized in Table 3. Based on the size of the contact areas and the depth of the maximum reduced stress, the area was defined to create a quality network of elements in the vicinity of the contact of three roller and cam types in the creation of appropriate models using the FEM. In the case of cam and roller contact with the crown with convex segments, only the results from the FEM analysis are shown in the table. Figure 14 shows the distribution of the reduced stress induced by contact of the said cam roller types with the cam. Figure 15 shows the course of the maximum reduced stress in a depth of \n
\n | Straight | \nCrowned | \nPart-crown | \n||
---|---|---|---|---|---|
Load | \n\n\n | \n40,000 | \n15,000 | \n35,000 | \n|
Hertzian pressure | \n\n\n | \n2500 | \n2400 | \n2400 | \n|
Maximum reduced stress | \nHertz theory | \n\n\n \n\n | \n1440 | \n1370 | \n1480 | \n
MKP | \n1970 | \n1360 | \n|||
Major contact radii | \n\n\n | \n— | \n5.555 | \n— | \n|
Half width of contact/minor contact radii | \n\n\n | \n0.586 | \n0.538 | \n— | \n|
Depth of maximum reduced stress | \n\n\n | \n0.42 | \n0.38 | \n0.38 | \n
Summary of results.
The stress state in the symmetry plane \n\nxz\n\n determined by FEM.
The course of the maximum reduced stress depending on the cam width.
From Table 3 and Figures 14 and 15, it is evident that there is an increase in the size of the reduced stresses in the vicinity of the profile discontinuities. This feature is particularly evident in the case of a cylindrical roller, where the contact between the roller and the cam cannot be regarded as merely straight but rather as a more complex three-dimensional type of contact. Therefore, Hertz’s theory of contact cannot be applied to this type of contact around the shape discontinuities. Based on this theory, there are very good results compared to the FEM in contact of the general body with the cylindrical one and inside the contact area of the two cylindrical bodies with parallel axes. Furthermore, it is clear that a uniform distribution of stress can be achieved by such a shape of a roller crown whose profile includes the straight and two circular portions according to the schematic representation in Figure 12. This roller crown profile is advantageous in terms of load transfer capacity and process of its manufacture.
\nThe presented chapter gives basic information on the stress problems related to a general kinematic pair of cam mechanisms. This type of kinematic pair is formed with at least one cam and a follower. The general cam mechanism is a very simple three-member mechanical system, which can implement the required working movements very accurately. Therefore, they are widely used in the design of various machines and equipment of the manufacturing industry. With the increasing pressure on the size and quality of machinery production of the manufacturing industry, the demand for its increased performance, reliability, and service life is growing. This fact is closely related to the detailed knowledge of the dynamic properties and behavior in the machinery during its operation. Thus, a dynamic response induced in the general kinematic pair is dependent both on the dynamic properties of all mechanical systems and on the prescribed displacement law. The choice of displacement law should be in conformity with the main requirements, which are, for example, reduced natural vibration, low dynamic load, high positional accuracy, and noiseless action.
\nDue to the effects of inertia and working forces, there are induced force ratios in the general kinematic pair that are the cause of contact strain. If a certain limit on this strain is exceeded, fatigue damage of the cam and follower contact surfaces may occur in the operation of the cam mechanisms. So knowledge of the distribution of the contact stress and its size are necessary when designing cam mechanisms. Contact stress expressed in Hertz pressure or the principal stresses becomes the criterion for determining the lifetime of the working areas of the mentioned kinematic pair. The lifetime itself depends on the choice of materials from which the individual parts are made and their physical and mechanical properties and the way of material processing and the production technologies of individual parts or the way and intensity of loading. There is currently a wide choice of materials for cams and cam followers of cam mechanisms. In technical practice, however, the most commonly used cams are made from steel. The surface of the cam or cam follower can be heat treated or chemically heat treated. The aim of the treatment is to achieve the desired mechanical or physical—chemical properties of the contact areas of the cam mechanisms. The purpose of this procedure is to increase the hardness and resistance of the contact surface against wear and to keep a resilient core of the respective component. The results from the abovementioned show that it is necessary to know various characteristic parameters describing material properties, heat treatment, or another technological processing for the lifetime estimation using theoretical methods. Therefore, experimental methods are an integral part of determining the lifetime of the working surface of the cam and the follower.
\nThe working surfaces of the general kinematic pair of the cam mechanism frequently operate under extreme conditions, which are high loads, high sliding speeds, and poor lubricating conditions. Thus, this fact can lead to wear or excessive friction and thereby reduce the service lifetime and efficiency. These effects may be reduced by the application of coating on the working surfaces of the cam and follower. Coating is a technological process consisting of the fact that a very thin layer (the order of thousands of millimeters) is applied to the surface of an object, which has a relatively high hardness and strength compared to the underlying material. The thin layer of the coating forms a so-called barrier of the surface layers of the respective component against their chemical and physically mechanical wear. Coatings are generally used to improve hardness and tribological properties, wear resistance, and oxidation of exposed surface layers of the components. The coatings extend the lifetime of the sliding and rolling surfaces and help reduce the required power consumption while increasing performance. This decreases the use of lubricants and allows the use of new material combinations in the implementation of the relevant machinery. In some cases, coatings are even a necessary structural element for higher mechanical and thermal loads.
\nAn effective way of analysis of the dynamic contact strain of the general kinematic pair of the cam mechanism is further presented here, which consists in the interaction of the knowledge and conclusions of Hertzian contact theory between two bodies and the advantages of using the finite element method. Using Hertz’s contact theory, we predict the shape and size of the contact region of bodies in contact. In this way, we define the region to create an even and fine mesh of elements of an appropriate size in the vicinity of contact. Taking into account the assumptions of the Hertzian theory, the definition of the FEM model of a general kinematic pair is considerably simplified, and this reduces the number of algebraic equations needed to solve this problem; thereby, the computational time is reduced. This method leads to the achievement of relevant results compared to the real state. The method is presented in the task of determining the effect of the roller crown shape on the cam stress.
\nThis chapter was created within the work on the TRIO II-FV20235 project—a project supported by the Ministry of Industry and Trade of the Czech Republic.
\nSpace orbital environment is characterized by several factors that affect experiments in physical sciences and influence the good functioning of all living systems, from cells to humans. The main factors are weightlessness, high-energy radiations, vacuum and temperature differences. These last two factors are generally mitigated by the vehicle yielding the necessary life support to the systems under study. The first two factors on the contrary cannot be completely compensated.
The concept of weightlessness will be developed further.
Perfect protection against high-energy radiations cannot be completely achieved, unless thick shielding walls are installed all around the spacecraft, which is presently excluded in view of launch costs per kg. Nevertheless, a vehicle in low Earth orbit (a few hundred kilometers altitude) stays relatively protected by Earth’s Van Allen radiation belts (inner energetic proton belt at 1,000–6,000 km altitude and outer energetic electron belt at 13,000–60,000 km altitude).
To these orbital factors, one should add the conditions at launch and during atmospheric reentry and landing of a spacecraft, i.e. important accelerations and vibrations, that can affect the quality of physiological samples or configurations obtained in microgravity (e.g. for crystals).
The state of microgravity, or more correctly micro-weightiness, exists in an orbital vehicle in a state of free fall, i.e. without any force acting on it except for gravitational forces [1]. This means that the vehicle must not be propelled or submitted to any other nongravitational force. Perfect weightlessness is an ideal state practically impossible to achieve. However, microgravity of an excellent quality (typically 10−5 g, where g is the acceleration of weightiness, commonly and erroneously mistaken for gravity1, with an average value of 9.81 m/s2) can be achieved in orbit.
Gravity (weightiness) disturbs certain experiments and reduces the field of investigation of some scientific domains. Gravity (weightiness) effects hide other effects pertaining to materials or fluids under study, and that depends often on intrinsic properties of matter or of its state. Convection in fluids, so evident that it is called “natural,” is caused by gravity (weightiness) acting on local differences of density caused by differences of temperature or concentration. The resulting Archimedes or buoyancy force induces an ascending motion of fluid zones of lesser density and a descending motion of fluid zones of larger density, creating convection cells in gases, liquids and solids in fusion, yielding disruptive phenomena in separation processes.
Although physical and biological processes are often investigated in hypergravity, e.g. in centrifuge, one knows less what happens in reduced gravity. However, in most cases, one cannot extrapolate from results obtained in hypergravity to microgravity, most of the phenomena being nonlinear in function of the gravity level. One observes many more differences while passing from 1 g to 0 g than between 5 g and 4 g, for example.
Many scientific fields profit from the peculiarities of weightlessness to enlarge their field of investigations. Material sciences, fluid physics and life sciences (biology and physiology) were the first to use microgravity, followed later by many other disciplines (combustion physico-chemistry, crystallography, fundamental physics, critical point phenomena, etc.) in view of varying a new experimental parameter: gravity. Microgravity allows to deepen scientific knowledge in domains that are hardly accessible on Earth.
Table 1 shows some of the scientific fields in which experiments were conducted in microgravity.
Physical sciences | Life sciences |
---|---|
Fundamental physics | Human research |
Complex plasmas and dust particle physics Aerosol particle motion Frictional interaction of dust and gas Plasma physics Aggregation phenomena | Integrated physiology Cardiovascular function Respiratory function Body fluid shift Central venous pressure system Digestive system Muscle and bone physiology Skeletal system Blood lactate studies Body mass tests Human locomotion Posture Bone models Neuroscience Neurobiology Vestibular functions Spatial orientation Motion sickness Motor skills |
Materials science | |
Thermophysical properties Thermophysical properties of melts New materials, products and processes Morphological stability and microstructures Physical chemistry Aggregation phenomena Granular matter | |
Fluid and combustion physics | |
Structure and dynamics of multiphase systems Pool boiling Heat and mass transfer Dynamics of drops and bubbles Thermophysical properties Interfacial phenomena Dynamics and stability of fluids Evaporation Complex dynamic systems Diffusion Foams Chemo-hydrodynamic pattern formation Combustion Droplet and spray combustion Soot concentration Combustion synthesis Laminar diffusion flames Fuel droplet evaporation Ignition behaviour | |
Biology | |
Plant physiology Statolith movement Gravitropism Gravireceptors Cell and developmental biology Animal physiology Aging processes Electrophysiological and morphological properties of human cells Osteoblast cells | |
Technology | |
ISS experiment validation Phase separation technologies for biological fluids Crew foot restraint Crew exercise devices Urine monitoring system | |
Technology | |
ISS experiment validation Metal halide lamps Micro-acceleration measurement |
Non-exhaustive list of research fields in microgravity.
Microgravity research allows to study the gravity effects on these different phenomena and the effects of other forces normally masked by gravity on Earth. Weightlessness became an experimental research tool that allows to transpose in microgravity the investigation of phenomena known on Earth but sometimes insufficiently understood, in order to investigate the fundamental processes and to understand their functioning without gravity.
Modifications appear when one studies matter behaviour in weightlessness. One observes on the one hand the disappearance of “natural” phenomena caused by gravity and, on the other hand, the preponderance in microgravity of phenomena that can hardly be observed in normal conditions of gravity. These modifications are particularly important for certain physical, chemical and metallurgical processes having at least one fluid phase: crystal growth, alloy solidification, separation of biological substances, etc.
The main differences that are observed for fluid phases in weightlessness are as follows.
Separation phenomena observed on Earth in multiphase systems that include a fluid phase disappear in microgravity. Sedimentation (precipitation of dissolved or suspended matter) and Archimedean buoyant force (or buoyancy, i.e. the force due to a liquid pressure on a body-immersed volume) disappear. The advantage of the absence of separation in weightlessness is the possibility of obtaining mixtures that are unstable on Earth and material alloys impossible to obtain on Earth or with great difficulty. A disadvantage of the absence of separation in weightlessness is the difficulty of eliminating the gaseous inclusions while, on Earth, degassing is done “naturally” (gaseous zones in liquid matrices go up to the free surface).
“Natural” convection disappears in fluids in microgravity. There is no more natural upward displacement of hot zones and downward displacement of cold zones. In fact, there is no up and no down. Other forces become dominant for movements in liquids in microgravity. These forces are linked to superficial or interfacial tension between two liquids. Indeed, such an interface behaves as an elastic “membrane” whose tension is a thermodynamic function of temperature (or concentration for solutions), as shown in Figure 1.
Liquid/gas interface submitted to a superficial tension gradient, yielding a Marangoni convection cell caused by the physical displacement of the interface membrane from the hot side (point 2) to the cold side (point 1) [1].
For an interface subjected to a temperature difference, superficial tension for most liquids is generally smaller for the hot side than for the cold side. The interface, i.e. the common layer formed by molecules of both fluids, physically moves parallelly to itself from the hot side to the cold side; this membrane deforms itself and slides from the hot side to the cold side. The liquid layers on both sides of the interface are dragged along by viscosity, and a new convection appears, called Marangoni convection, after the name of the Italian physicist who studied this phenomenon at the end of the nineteenth century. This phenomenon exists obviously also on Earth, but as its effect is much smaller than those caused by gravity, it is in general negligible and much more difficult to observe. Its study in microgravity allows thus to better understand the fundamental characteristics of liquid behaviour.
It is also because of the absence of “natural” convection that the shape of a combustion flame is different in weightlessness. On Earth, gases produced by the chemical reaction of combustion (e.g. of a candle wick), much hotter, rise, and fresh air oxygen migrate to the combustion centre to feed the combustion process. In microgravity, hot gases have no reason to rise anymore, and the flame is surrounded by a hemispherical ball formed by combustion gases (Figure 2), limiting the amount of fresh oxygen transfer.
Flames on ground in 1 g (left) and in microgravity in near 0 g (right). Notice the near-hemispherical shape of the flame in microgravity with the reddish-purple part on top due to some convection caused by small perturbations in the microgravity environment (photo credit: NASA).
In microgravity, hydrostatic pressure disappears. On Earth, it is responsible for the tendency of fluids to deform under the effect of their own weight, a liquid zone supporting the weight of zones on top. The same phenomenon exists for solids. Structures can be built that would collapse under their own weight on Earth, e.g. crystalline networks (Figure 3).
Protein crystals obtained with ESA’s Advanced Protein Crystallization Facility during the Life and Microgravity Spacelab mission on NASA Space Shuttle STS-98 in May 1995 (credit: Prof. Martial, University of Liege, Belgium).
Liquids in weightlessness, abandoned to themselves without any contact with a solid surface, form spherical drops (Figure 4), which is the minimal surface enclosing a given volume when subjected to the only forces of superficial tension.
Water drop in free float on ISS (credit: NASA).
On Earth, crucibles are used to melt alloys, which may contaminate the melt liquid phase. In weightlessness, the liquid phase can be maintained in a contactless levitation, without touching any solid walls, using an electrostatic, magnetic or acoustic confining (Figure 5). Many parameters of materials at high temperatures are still unknown and cannot be measured on Earth due to difficulties and limitations caused by crucible contamination and gravity effects.
Core element of an electromagnetic levitator (photo credit: DLR).
The list of the advantages and applications of microgravity to scientific research could be continued at length but is outside of the aim of this publication. The interested reader will find other examples and more details in Refs. [2, 3, 4, 5].
Initially developed in the 1950s and 1960s to support US and USSR space programs, space microgravity medical research quickly evolved. Manned spaceflights very quickly showed physiological changes in astronauts and cosmonauts. The duration of spaceflights has increased throughout the years, from a few hours at the beginning of the 1960s to several months (or even more than a year) today on board the International Space Station (ISS, Figure 13). The ISS allows to conduct and to repeat experiments during several years.
New phenomena have been observed on astronauts, some of these effects appearing only after several weeks or months in space. Despite the large number of hours spent in orbit around the Earth by astronauts and cosmonauts from all countries involved in space research and exploration, some problems are still far from being fully understood, and the necessary solutions have not yet been found.
Although physiological systems of human organism function interdependently, one can classify physiological effects of microgravity in four categories:
Perturbations of sensorial systems related to balance, orientation and the vestibular system
Modifications of bodily fluid distribution and their impact on the cardiovascular system
Effects on metabolism and bodily functions
The adaptive processes of muscular and skeletal systems and their pathological consequences
Relevant knowledge and research on human physiology are presented below, and more details can also be found in Refs. [6, 7, 8, 9, 10, 11].
On Earth, in a normal gravity environment, the human body has three means to obtain the information of the reference vertical direction and of the top-bottom orientation, characteristic of the gravitational environment on our planet.
The main system is the vestibular system, which is double, located in the inner ear. In one of these organs, small crystals of calcium carbonate called otoliths weigh on a membrane with nervous endings. The semicircular canals form another sensor. Formed by the three canals in planes approximatively orthogonal to each other, a physiological liquid moves by inertia in these canals during a head movement, stimulating nervous endings in the canals. The combination of the information coming from the otoliths and semicircular canals allows the brain to interpret the movement and the position of the head.
The second source of information is the visual system. The visual information allows the brain to recognize the body position with respect to external references (floor, ceiling, walls).
The third information source is the proprioceptive system, constituted of the whole of skin tactile perceptions, articulations and muscle tension. The neck proprioceptive system is the most developed and informs the brain on the position of the head with respect to the rest of the body.
In weightlessness and in absence of accelerated motion, there is no stimulation of the vestibular system. Otoliths are no longer attracted downward by gravity, and the semicircular canals are no longer stimulated. However, the visual and proprioceptive systems continue to function normally. Information sent by these different systems to the brain are incoherent for an organism used to normal gravity and create confusion in the brain zone that normally treats the information on position and orientation. This confusion often yields dizzy spells and nausea and sometime triggers the reflex of emptying the stomach. In short, the subject is sick. This sickness, called space adaptation syndrome, affects most astronauts. On average, one out of two astronauts suffers from nausea during the first few days of spaceflight. After a day or two, the human organism adapts to the new environment, and astronauts can continue to function and work “normally.” After the flight, the balance and orientation systems readapt quickly to the Earth’s environment.
On Earth, while standing in normal gravity, arterial blood pressure is normally distributed such that, if intracardiac pressure is taken as unity, it is approximately double in feet arteries and two third at head level. While lying down, the distribution of blood pressure is more uniform. Passing from the lying to the standing position yields a blood flow toward the lower part of the body, and blood pressure diminishes in the head. Known as orthostatic postural intolerance, the change of blood pressure is detected by baroreceptors in the vascular system and close to the heart. These receptors send signals that yield, firstly, an increase of cardiac rhythm to compensate the blood volume decrease in head arteries and, secondly, a contraction of arteries in the lower body to diminish the blood flow toward the legs.
In microgravity, gravity does not attract liquids downward anymore, and a redistribution of body fluids takes place. A volume of approximately two liters of body fluids is displaced from the lower extremities to the upper part of the body, increasing the blood volume and pressure in the heart. The volume and blood flow receptors are alerted, and this new situation is interpreted as an overload of the blood system. The reaction of body liquid elimination starts and yields a complex hormonal game, which results in a natural elimination by urine of body liquids. The organism adapts to this new environment, and a new balance is established after 4–5 days.
On the other hand, liquid transfer from lower members toward the upper body has other secondary effects: face swelling due to blood rush in the head, the increase of intraocular pressure, and sinus congestion. These secondary effects disappear up to a certain point after a few days in microgravity. Back on Earth, the organism readapts to a 1 g environment.
The results of experiments performed with ultrasound echocardiography show a diminution of the left ventricle and auricle volumes during a spaceflight of several weeks. However, after the flight, the cardiac muscle comes back to a normal state.
In microgravity, a decrease of cardiac rhythm and of arterial tension is observed, the heart not needing to pump blood against gravity’s downward pull (Figure 6).
Experiments during aircraft parabolic flights (left) showed (right) a decrease in heart rate, seen at the beginning of microgravity (arrows), i.e. an increase of duration between successive peaks, corresponding to increased vagal modulation of the heart rate. A sudden increase is also seen in pulse blood pressure (difference between maximum and minimum pressures), indicating an increase in stroke volume (ECG, electrocardiogram; BP, blood pressure) (credit: Left, ESA; right, Prof. A. Aubert, Katholieke Universiteit Leuven, Belgium).
A high tachycardia (increase of the cardiac rhythm) is observed also at launch, due to psychological stress, but also necessary to compensate the effects of accelerations, in the order of 3–4 g, with a maximum of 8 g.
Visual impairment and intracranial pressure are another consequence of the upward body fluid shifts, the head filling with blood and other bodily fluids. The various consequences are an increase in intracranial pressure that can cause headache of varying levels of severity and an increase of the intraocular pressure that affects the visual performance and other more minor effects such as congestion of the sinuses. These effects, although observed and investigated for several years, are thought to be temporary as they tend to disappear after return to Earth.
However, intracranial pressure and visual impairment were only recently recognized as more serious as they could impair the performance of astronauts during long-duration 0 g travels in space.
In microgravity, the main physiological functions are practically unchanged. Astronauts can eat and drink without major constraints. Digestion and intestinal transit are accomplished also nearly normally, except that gravity action is no longer present.
Breathing is also made without too important problems. However, the breathing mechanism is altered: the distribution of inspired and expired gases in the lungs and oxygen exchanges in blood hemoglobin at the level of pulmonary alveoli are modified. The way to breathe is also modified: statistically, in weightlessness, the forced movement of the abdomen contributes more to the breathing mechanism.
Astronauts can also sleep in space. However, daily and sleep rhythms are disturbed. Indeed, on board the ISS in low Earth orbit at 400 km altitude, day and night alternation repeats approximately every 90 min. Astronauts see a sunrise and sunset 16 times per terrestrial 24 h a “day.” Psychological and emotional factors and travel excitement intervene also. To remedy it, one imposes a strict and well-established schedule taking into account human natural rhythms. On board the ISS, a three times 8-h schedule is applied: 8 h for sleep, 8 h for work depending on missions and 8 h for personal time, meals, rests, etc. This schedule is purely theoretical as astronauts on board the ISS spend much more of their time to work, although for long-duration stays on ISS, schedules are loose, and longer rest periods are foreseen some days, generally used by astronauts to watch Earth through windows, mainly the cupola (Figure 7).
NASA astronaut Karen Nyberg, Expedition 37 flight engineer in 2013, enjoys the view of earth from the windows in the ESA-built cupola of the International Space Station. A blue and white part of earth is visible through some of the seven windows of the cupola (photo credit: NASA).
After long stays in weightlessness, changes are observed in blood composition that can be problematic. Firstly, the number of red blood cells and the hemoglobin level decrease. Secondly, red blood cells of unequal sizes and of abnormal shapes have been also discovered. After 6 months in microgravity in orbit, up to 2% of ovalized red blood cells have been observed in Russian cosmonauts. Thirdly, the immune defense system of astronauts diminishes in microgravity after approximatively 7 days of flight. One observes a reduction of production of lymphocyte T cells (the white blood cells) that intervene in the immune responses and in antibody production. This observation did not find so far a satisfactory fundamental explanation, and this problem could be the one that would impede mankind to adapt to long-duration space travels in microgravity. Astronauts are more prone to infections in space, and they need more time to recover after an infection on ground after their return. The immune system is back to its normal preflight level after a period of 5–10 days after return to Earth.
In microgravity, the first effect that is noticed is the spine extension up to a point that astronauts can gain a few centimeters in height. This is due to the partial decompression of intervertebral discs that do not have to support the weight of the upper body anymore. Back on Earth, after the flight, this effect disappears, and height becomes normal again but with, sometime, the risk of having a nerve blocked between discs and vertebrae. Furthermore, some astronauts complained of back pains during or after a spaceflight, probably caused by this phenomenon of spine extension.
The muscular system atrophy is a second consequence, observed after some days in weightlessness. In particular, the most affected muscles are those that control posture and that contribute to support the body weight on Earth. In microgravity, the natural position that astronauts take is a curved position with the legs slightly bent. One floats freely and moves by pushing oneself against a wall, using the action-reaction principle. One notices thus a muscle atrophy, a loss of mass of muscles and the elimination of muscular proteins (Figure 8).
British ESA astronaut Tim Peake operates the muscle atrophy research and exercise system (MARES) equipment inside the Columbus module. MARES is an ESA facility used for research on musculoskeletal, biomechanical and neuromuscular human physiology to better understand the effects of microgravity on the muscular system (photo credit: NASA/ESA).
By practicing regularly (more than 2 h per day!) and by applying sometime treatments of muscular fiber electrostimulation, astronauts and cosmonauts have no difficulties to readapt upon return to Earth after a more than 6-month mission.
Bone demineralization, and mainly decalcification, is the most important and serious physiological phenomenon observed in microgravity. Appearing only after 1–2 months in orbit, this could be the second problem that could thwart the hopes of mankind to adapt to space travels in weightlessness.
The loss of calcium is still not completely understood. One knows that decalcification is related to an atrophy of bone fibrous cells containing calcium, corresponding to the part of the bone that allows the marrow to pass. This effect seems to be irreversible once it has started. The rate of calcium loss varies from an astronaut to another and varies also from a type of bone to another. Numerous experiments yield sometime diverging results. On one side, one observes an increase of activity of osteoclastic cells, whose role is to eliminate and resorb elements of bone tissues. On the other side, some results show that bone demineralization would be due to a decrease of activity of osteoblastic cells, responsible for regenerating bone tissues.
This problem of bone decalcification resembles by certain aspects osteoporosis, an illness known on Earth affecting mainly elderly people. This sickness yields a change in the structure (demineralization) of bones, but the composition stays globally the same. The bone loses in thickness, fragilizes and fractures more easily. This shows the importance of conducting research in microgravity on astronauts to better understand this sickness and to contribute in finding a cure for it.
All the means to generate microgravity are based on the principle of free fall; any other method will not result in a real microgravity environment but in a simulated microgravity environment. Microgravity is created in a non-inertial reference frame attached to a vehicle in free fall, in which the resultant of forces other than gravity is null or negligible.
Figure 9 summarizes the different platforms used for microgravity research in an increasing order of microgravity duration.
Reduced gravity platforms accessible to microgravity researchers (vertical axis, duration of microgravity; horizontal axis, quality of microgravity) (credit: DLR).
Drop tubes and drop towers provide a few seconds (up to 5 s) in the vertical drop mode, where an experimental payload is literally dropped in vacuum or behind a shield to reduce the perturbing effect of air friction.
The level of microgravity obtained in the drop tube of NASA Marshall Centre of 105 m high and 25 cm diameter is in the order of 10−6 g during 4.6 s in a vacuum. In Europe, the ZARM drop tower in Bremen, Germany (Figure 10), is 110 m high with a diameter of 3.5 m. Experiment capsules fall during 4.7 s in vacuum, yielding microgravity levels of 10−5 g. The microgravity duration can be doubled up to 9.5 s by launching the experiment capsule in a catapult mode from the bottom of the tower upward, falling freely first upward and then downward [12, 13].
The ZARM drop tower in Bremen, Germany. The 146 m high building protects the free fall facility from atmospheric perturbation and wind (photo credit: ZARM).
Aircraft parabolic flights provide a reduced gravity environment of approximately 20 s, with the major advantage of having human operators and subjects on board. The level of microgravity is typically in 10−2 g when attached to the floor structure that can be improved down to 10−3 g for a few seconds when left free-floating (Figure 11). This important microgravity platform is addressed in the next chapter.
During a parabolic flight on board the Airbus A300 ZERO-G during an ESA campaign, several experimental racks are visible to the left and the back, while one of the authors floats freely “upside down.” There is no “up” and “down” in weightlessness (photo credit: ESA).
Sounding rocket flights, for which microgravity levels are in the order of 10−4–10−5 g, are used for automated or remotely operated experiments with relatively reduced volumes. Depending on the size of the rocket and the engine used, the duration of microgravity during the ballistic phase of the flights varies between 3 and 14 min [14].
In the near future, suborbital flights will provide microgravity duration in the order of 3–4 min for paying customers but also for microgravity experiments. There are typically two US companies that are working on suborbital vehicles (Figure 12): Blue Origin with the New Shephard capsule and a reusable rocket and Virgin Galactic and the SpaceShipTwo spaceplane carried by the WhiteKnightTwo airplane carrier. These two systems would carry passengers and experiments up to an altitude of 100 km or more in a propelled mode and continue in a ballistic mode for approximately 3–4 min after propulsion has stopped.
Two suborbital facilities in development: (left) the New Shephard capsule with a reusable rocket (credit: Blue origin) and (right) the WhiteKnightTwo airplane carrying the SpaceShipTwo spaceplane (photo credit: Virgin galactic).
Manned orbital platforms provide microgravity periods of several years for the International Space Station (ISS, Figure 13) [15, 16, 17], and the future Chinese Space Station is foreseen to be assembled in orbit in 2022 (Figure 14). Residual accelerations are in the order of 10−2–10−4 g, depending on internal perturbations (e.g. crew movements) and external ones.
The International Space Station (ISS) is the first major international project that includes 14 countries in its realization: The USA, Russia, Canada, Japan and 10 European countries (France, Germany, Italy, Belgium, the Netherlands, Spain, Sweden, Switzerland, Denmark and Norway). With a total mass of 440 tons (but weighing 0 kg ...), the ISS is in low earth orbit between 400 and 450 km altitude at 51.6° inclination. Since November 2000, the station is inhabited by permanent international crews (photo: NASA).
The Chinese Space Station foreseen to be launched and assembled in the coming years with an assembly completed for 2022. From left, the Tianzhou (meaning “heavenly vessel” in Chinese Mandarin) cargo freighter docked to the Tianhe (“harmony of the heavens”) core module in the Centre; a piloted Shenzhou (“divine vessel”) vehicle is connected to a node in front of Tianhe, which are connected to two scientific modules: Wentian (“quest for the heavens,” at right) and Mengtian (“dreaming of the heavens,” left) (credit: CMSA).
Space missions of orbital platforms and of sounding rockets require a long preparation, typically of several years, and should be considered for experiments that need a long exposition duration to microgravity. The relatively short preparation time for the use of drop tubes and towers and of aircraft parabolic flights (typically of few days to few months) renders them particularly attractive for short-duration experiments of a few seconds. The utilization of these experimental platforms of earthbound microgravity must be considered as preparatory and complementary to space missions.
Let us insist on the fact that the platforms described in this section do not simulate microgravity but that they really create microgravity, even if it is not always perfect, as all these means are in free fall.
To the contrary of the means creating microgravity, simulation methods do not allow to really create microgravity. The simulation means allow to obtain experimental configurations in which certain aspects of phenomena can be studied in a way similar to what could be observed in microgravity but without being in weightlessness.
Therefore, these methods have important limitations that reduce their scientific interest to the investigations of some very specific cases. The results obtained by these simulation methods generally complete those obtained in real microgravity. In none of the three following configurations, microgravity is really created as there is no free fall.
The first simulation method was used at the end of the nineteenth century by a Belgian physicist, Joseph Plateau, who gave his name to this method. The principle is simple: it consists in immersing a liquid in another immiscible liquid matrix having the same volumetric mass. By Archimedes principle, the buoyancy exerted by the liquid matrix of volumetric mass ρ1 on a volume V of a liquid of volumetric mass ρ2 is directed along the gravity acceleration vector and reads
This force becomes null for ρ1 = ρ2, yielding results similar to what could be obtained in weightlessness when g = 0. In the Plateau configuration, the gravity force is not balanced by inertia forces but by a buoyancy force.
Only static configurations are truly well simulated with this method, e.g. configurations of static equilibrium of liquid zones.
The second simulation method is less known. It consists in balancing locally the force of gravity acting on a body by a magnetic or electrostatic force acting in the other direction. The effects of two fields, the gravitational field and a magnetic or electrostatic field, have to be locally balanced. One sees immediately the limitation of this configuration that would work only for bodies sensitive to magnetic induction or electrically charged. Furthermore, the power needed to maintain these fields is quite important and limits the size of observed configurations. Nevertheless, this method is used sometime to investigate magnetohydrodynamic problems in the absence of gravity effects.
The third simulation method is what is called the dimensionless reduction. This method mainly applies to fluid research for which scientists use a series of dimensionless numbers describing the ratios of different forces acting on fluids. Reducing physical dimensions of an experimental liquid zone greatly diminishes effects caused by gravity in comparison to other forces acting on fluids, e.g. superficial tension force or capillarity forces. One manages to build floating liquid zone of a few millimeters size that allow to study certain phenomena. The main limitations of this method are linked to reduced sizes: firstly, they make it difficult to install precise means of observation and measurement; secondly, they reduce the field of investigation to limited ranges of values of other effects specific to fluids.
Space medical and physiological research does not limit itself to conducting medical experiments in orbit or during parabolic flights but relies also on results obtained by earthbound means. For research on adaptation of the human body to weightlessness, scientists use two simulation techniques that allow within certain limits to recreate the effects of microgravity on the human body. It consists firstly of immobilization (or hypokinesia, Figure 15) in a horizontal position or slightly inclined (head-down) that simulates the shift of body fluids, mainly blood, toward the upper part of the body like in weightlessness.
Head-down bed rest simulates microgravity effects on human physiology. Subjects stay in slightly tilted head-down (typically 6°) beds for weeks or months at a time (photo credit: CNES/ESA).
The second technique is water immersion. As the human body is mainly made of water, buoyancy induces conditions partially similar to microgravity acting on the human body, somewhat akin to Plateau’s configuration. A variant of water immersion, called dry immersion, is also used sometime where the subject is placed in an elastic or plastic sheet in a liquid matrix, such that the subject is immersed in the liquid but without direct contact with the liquid.
A better understanding of the effects of microgravity on physics and the human body, from cells to body systems, is essential if the human exploration of outer space is to continue. The capacity to conduct research in the microgravity environment provided by spaceflight is fundamental, especially given current plans to expand long-term missions in low Earth orbit and to establish the commercial use of space, together with the ultimate goals of creating a human colony on the Moon and sending a first crewed mission to Mars. Nonetheless, there are many limiting factors that restrict the performance of experiments in space, such as the high costs involved in sending resources and equipment up into space, the safety requirements to which experimental devices must adhere and the small number of astronauts per flight. These constraining factors have motivated the establishment of ground-based research facilities and parabolic flights. The latter presents some limitations in terms of the short period of time of exposure to microgravity given and the hypergravity condition that precedes and succeeds each parabola. However, it is the only provider of microgravity, in which experiments in physics, biology, physiology and medicine can be conducted by human operators and volunteers. Parabolic flights are not a perfect analogue of spaceflight, but they remain a valuable research tool that enables research and testing to take place and a better understanding of the effects of microgravity, assisting academia, the private sector and governments to better design future plans for the human exploration of outer space.
"I work with IntechOpen for a number of reasons: their professionalism, their mission in support of Open Access publishing, and the quality of their peer-reviewed publications, but also because they believe in equality. Throughout the world, we are seeing progress in attracting, retaining, and promoting women in STEMM. IntechOpen are certainly supporting this work globally by empowering all scientists and ensuring that women are encouraged and enabled to publish and take leading roles within the scientific community." Dr. Catrin Rutland, University of Nottingham, UK
",metaTitle:"Advantages of Publishing with IntechOpen",metaDescription:"We have more than a decade of experience in Open Access publishing. \n\n ",metaKeywords:null,canonicalURL:null,contentRaw:'[{"type":"htmlEditorComponent","content":"We have more than a decade of experience in Open Access publishing. The advantages of publishing with IntechOpen include:
\\n\\nOur platform – IntechOpen is the world’s leading publisher of OA books, built by scientists, for scientists.
\\n\\nOur reputation – Everything we publish goes through a two-stage peer review process. We’re proud to count Nobel laureates among our esteemed authors. We meet European Commission standards for funding, and the research we’ve published has been funded by the Bill and Melinda Gates Foundation and the Wellcome Trust, among others. IntechOpen is a member of all relevant trade associations (including the STM Association and the Association of Learned and Professional Society Publishers) and has a selection of books indexed in Web of Science's Book Citation Index.
\\n\\nOur expertise – We’ve published more than 4,500 books by more than 118,000 authors and editors.
\\n\\nOur reach – Our books have more than 130 million downloads and more than 146,150 Web of Science citations. We increase citations via indexing in all the major databases, including the Book Citation Index at Web of Science and Google Scholar.
\\n\\nOur services – The support we offer our authors and editors is second to none. Each book in our program receives the following:
\\n\\nOur end-to-end publishing service frees our authors and editors to focus on what matters: research. We empower them to shape their fields and connect with the global scientific community.
\\n\\n"In developing countries until now, advancement in science has been very limited, because insufficient economic resources are dedicated to science and education. These limitations are more marked when the scientists are women. In order to develop science in the poorest countries and decrease the gender gap that exists in scientific fields, Open Access networks like IntechOpen are essential. Free access to scientific research could contribute to ameliorating difficult life conditions and breaking down barriers." Marquidia Pacheco, National Institute for Nuclear Research (ININ), Mexico
\\n\\nInterested? Contact Ana Pantar (book.idea@intechopen.com) for more information.
\\n"}]'},components:[{type:"htmlEditorComponent",content:'We have more than a decade of experience in Open Access publishing. The advantages of publishing with IntechOpen include:
\n\nOur platform – IntechOpen is the world’s leading publisher of OA books, built by scientists, for scientists.
\n\nOur reputation – Everything we publish goes through a two-stage peer review process. We’re proud to count Nobel laureates among our esteemed authors. We meet European Commission standards for funding, and the research we’ve published has been funded by the Bill and Melinda Gates Foundation and the Wellcome Trust, among others. IntechOpen is a member of all relevant trade associations (including the STM Association and the Association of Learned and Professional Society Publishers) and has a selection of books indexed in Web of Science's Book Citation Index.
\n\nOur expertise – We’ve published more than 4,500 books by more than 118,000 authors and editors.
\n\nOur reach – Our books have more than 130 million downloads and more than 146,150 Web of Science citations. We increase citations via indexing in all the major databases, including the Book Citation Index at Web of Science and Google Scholar.
\n\nOur services – The support we offer our authors and editors is second to none. Each book in our program receives the following:
\n\nOur end-to-end publishing service frees our authors and editors to focus on what matters: research. We empower them to shape their fields and connect with the global scientific community.
\n\n"In developing countries until now, advancement in science has been very limited, because insufficient economic resources are dedicated to science and education. These limitations are more marked when the scientists are women. In order to develop science in the poorest countries and decrease the gender gap that exists in scientific fields, Open Access networks like IntechOpen are essential. Free access to scientific research could contribute to ameliorating difficult life conditions and breaking down barriers." Marquidia Pacheco, National Institute for Nuclear Research (ININ), Mexico
\n\nInterested? Contact Ana Pantar (book.idea@intechopen.com) for more information.
\n'}]},successStories:{items:[]},authorsAndEditors:{filterParams:{sort:"featured,name"},profiles:[{id:"6700",title:"Dr.",name:"Abbass A.",middleName:null,surname:"Hashim",slug:"abbass-a.-hashim",fullName:"Abbass A. Hashim",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/6700/images/1864_n.jpg",biography:"Currently I am carrying out research in several areas of interest, mainly covering work on chemical and bio-sensors, semiconductor thin film device fabrication and characterisation.\nAt the moment I have very strong interest in radiation environmental pollution and bacteriology treatment. The teams of researchers are working very hard to bring novel results in this field. I am also a member of the team in charge for the supervision of Ph.D. students in the fields of development of silicon based planar waveguide sensor devices, study of inelastic electron tunnelling in planar tunnelling nanostructures for sensing applications and development of organotellurium(IV) compounds for semiconductor applications. I am a specialist in data analysis techniques and nanosurface structure. I have served as the editor for many books, been a member of the editorial board in science journals, have published many papers and hold many patents.",institutionString:null,institution:{name:"Sheffield Hallam University",country:{name:"United Kingdom"}}},{id:"54525",title:"Prof.",name:"Abdul Latif",middleName:null,surname:"Ahmad",slug:"abdul-latif-ahmad",fullName:"Abdul Latif Ahmad",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"20567",title:"Prof.",name:"Ado",middleName:null,surname:"Jorio",slug:"ado-jorio",fullName:"Ado Jorio",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Universidade Federal de Minas Gerais",country:{name:"Brazil"}}},{id:"47940",title:"Dr.",name:"Alberto",middleName:null,surname:"Mantovani",slug:"alberto-mantovani",fullName:"Alberto Mantovani",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"12392",title:"Mr.",name:"Alex",middleName:null,surname:"Lazinica",slug:"alex-lazinica",fullName:"Alex Lazinica",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/12392/images/7282_n.png",biography:"Alex Lazinica is the founder and CEO of IntechOpen. After obtaining a Master's degree in Mechanical Engineering, he continued his PhD studies in Robotics at the Vienna University of Technology. Here he worked as a robotic researcher with the university's Intelligent Manufacturing Systems Group as well as a guest researcher at various European universities, including the Swiss Federal Institute of Technology Lausanne (EPFL). During this time he published more than 20 scientific papers, gave presentations, served as a reviewer for major robotic journals and conferences and most importantly he co-founded and built the International Journal of Advanced Robotic Systems- world's first Open Access journal in the field of robotics. Starting this journal was a pivotal point in his career, since it was a pathway to founding IntechOpen - Open Access publisher focused on addressing academic researchers needs. Alex is a personification of IntechOpen key values being trusted, open and entrepreneurial. Today his focus is on defining the growth and development strategy for the company.",institutionString:null,institution:{name:"TU Wien",country:{name:"Austria"}}},{id:"19816",title:"Prof.",name:"Alexander",middleName:null,surname:"Kokorin",slug:"alexander-kokorin",fullName:"Alexander Kokorin",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/19816/images/1607_n.jpg",biography:"Alexander I. Kokorin: born: 1947, Moscow; DSc., PhD; Principal Research Fellow (Research Professor) of Department of Kinetics and Catalysis, N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow.\r\nArea of research interests: physical chemistry of complex-organized molecular and nanosized systems, including polymer-metal complexes; the surface of doped oxide semiconductors. He is an expert in structural, absorptive, catalytic and photocatalytic properties, in structural organization and dynamic features of ionic liquids, in magnetic interactions between paramagnetic centers. The author or co-author of 3 books, over 200 articles and reviews in scientific journals and books. He is an actual member of the International EPR/ESR Society, European Society on Quantum Solar Energy Conversion, Moscow House of Scientists, of the Board of Moscow Physical Society.",institutionString:null,institution:{name:"Semenov Institute of Chemical Physics",country:{name:"Russia"}}},{id:"62389",title:"PhD.",name:"Ali Demir",middleName:null,surname:"Sezer",slug:"ali-demir-sezer",fullName:"Ali Demir Sezer",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/62389/images/3413_n.jpg",biography:"Dr. Ali Demir Sezer has a Ph.D. from Pharmaceutical Biotechnology at the Faculty of Pharmacy, University of Marmara (Turkey). He is the member of many Pharmaceutical Associations and acts as a reviewer of scientific journals and European projects under different research areas such as: drug delivery systems, nanotechnology and pharmaceutical biotechnology. Dr. Sezer is the author of many scientific publications in peer-reviewed journals and poster communications. Focus of his research activity is drug delivery, physico-chemical characterization and biological evaluation of biopolymers micro and nanoparticles as modified drug delivery system, and colloidal drug carriers (liposomes, nanoparticles etc.).",institutionString:null,institution:{name:"Marmara University",country:{name:"Turkey"}}},{id:"61051",title:"Prof.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:null},{id:"100762",title:"Prof.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"St David's Medical Center",country:{name:"United States of America"}}},{id:"107416",title:"Dr.",name:"Andrea",middleName:null,surname:"Natale",slug:"andrea-natale",fullName:"Andrea Natale",position:null,profilePictureURL:"//cdnintech.com/web/frontend/www/assets/author.svg",biography:null,institutionString:null,institution:{name:"Texas Cardiac Arrhythmia",country:{name:"United States of America"}}},{id:"64434",title:"Dr.",name:"Angkoon",middleName:null,surname:"Phinyomark",slug:"angkoon-phinyomark",fullName:"Angkoon Phinyomark",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/64434/images/2619_n.jpg",biography:"My name is Angkoon Phinyomark. I received a B.Eng. degree in Computer Engineering with First Class Honors in 2008 from Prince of Songkla University, Songkhla, Thailand, where I received a Ph.D. degree in Electrical Engineering. My research interests are primarily in the area of biomedical signal processing and classification notably EMG (electromyography signal), EOG (electrooculography signal), and EEG (electroencephalography signal), image analysis notably breast cancer analysis and optical coherence tomography, and rehabilitation engineering. I became a student member of IEEE in 2008. During October 2011-March 2012, I had worked at School of Computer Science and Electronic Engineering, University of Essex, Colchester, Essex, United Kingdom. In addition, during a B.Eng. I had been a visiting research student at Faculty of Computer Science, University of Murcia, Murcia, Spain for three months.\n\nI have published over 40 papers during 5 years in refereed journals, books, and conference proceedings in the areas of electro-physiological signals processing and classification, notably EMG and EOG signals, fractal analysis, wavelet analysis, texture analysis, feature extraction and machine learning algorithms, and assistive and rehabilitative devices. I have several computer programming language certificates, i.e. Sun Certified Programmer for the Java 2 Platform 1.4 (SCJP), Microsoft Certified Professional Developer, Web Developer (MCPD), Microsoft Certified Technology Specialist, .NET Framework 2.0 Web (MCTS). I am a Reviewer for several refereed journals and international conferences, such as IEEE Transactions on Biomedical Engineering, IEEE Transactions on Industrial Electronics, Optic Letters, Measurement Science Review, and also a member of the International Advisory Committee for 2012 IEEE Business Engineering and Industrial Applications and 2012 IEEE Symposium on Business, Engineering and Industrial Applications.",institutionString:null,institution:{name:"Joseph Fourier University",country:{name:"France"}}},{id:"55578",title:"Dr.",name:"Antonio",middleName:null,surname:"Jurado-Navas",slug:"antonio-jurado-navas",fullName:"Antonio Jurado-Navas",position:null,profilePictureURL:"https://mts.intechopen.com/storage/users/55578/images/4574_n.png",biography:"Antonio Jurado-Navas received the M.S. degree (2002) and the Ph.D. degree (2009) in Telecommunication Engineering, both from the University of Málaga (Spain). He first worked as a consultant at Vodafone-Spain. From 2004 to 2011, he was a Research Assistant with the Communications Engineering Department at the University of Málaga. In 2011, he became an Assistant Professor in the same department. From 2012 to 2015, he was with Ericsson Spain, where he was working on geo-location\ntools for third generation mobile networks. Since 2015, he is a Marie-Curie fellow at the Denmark Technical University. His current research interests include the areas of mobile communication systems and channel modeling in addition to atmospheric optical communications, adaptive optics and statistics",institutionString:null,institution:{name:"University of Malaga",country:{name:"Spain"}}}],filtersByRegion:[{group:"region",caption:"North America",value:1,count:5775},{group:"region",caption:"Middle and South America",value:2,count:5239},{group:"region",caption:"Africa",value:3,count:1721},{group:"region",caption:"Asia",value:4,count:10411},{group:"region",caption:"Australia and Oceania",value:5,count:897},{group:"region",caption:"Europe",value:6,count:15810}],offset:12,limit:12,total:118378},chapterEmbeded:{data:{}},editorApplication:{success:null,errors:{}},ofsBooks:{filterParams:{sort:"dateendthirdsteppublish",topicid:"10"},books:[],filtersByTopic:[{group:"topic",caption:"Agricultural and Biological Sciences",value:5,count:18},{group:"topic",caption:"Biochemistry, Genetics and Molecular Biology",value:6,count:5},{group:"topic",caption:"Business, Management and Economics",value:7,count:2},{group:"topic",caption:"Chemistry",value:8,count:8},{group:"topic",caption:"Computer and Information Science",value:9,count:6},{group:"topic",caption:"Earth and Planetary Sciences",value:10,count:7},{group:"topic",caption:"Engineering",value:11,count:20},{group:"topic",caption:"Environmental Sciences",value:12,count:2},{group:"topic",caption:"Immunology and Microbiology",value:13,count:4},{group:"topic",caption:"Materials Science",value:14,count:5},{group:"topic",caption:"Mathematics",value:15,count:1},{group:"topic",caption:"Medicine",value:16,count:25},{group:"topic",caption:"Neuroscience",value:18,count:2},{group:"topic",caption:"Pharmacology, Toxicology and Pharmaceutical Science",value:19,count:3},{group:"topic",caption:"Physics",value:20,count:3},{group:"topic",caption:"Psychology",value:21,count:4},{group:"topic",caption:"Robotics",value:22,count:1},{group:"topic",caption:"Social Sciences",value:23,count:3},{group:"topic",caption:"Technology",value:24,count:1},{group:"topic",caption:"Veterinary Medicine and Science",value:25,count:1}],offset:0,limit:12,total:null},popularBooks:{featuredBooks:[{type:"book",id:"9521",title:"Antimicrobial Resistance",subtitle:"A One Health Perspective",isOpenForSubmission:!1,hash:"30949e78832e1afba5606634b52056ab",slug:"antimicrobial-resistance-a-one-health-perspective",bookSignature:"Mihai Mareș, Swee Hua Erin Lim, Kok-Song Lai and Romeo-Teodor Cristina",coverURL:"https://cdn.intechopen.com/books/images_new/9521.jpg",editors:[{id:"88785",title:"Prof.",name:"Mihai",middleName:null,surname:"Mares",slug:"mihai-mares",fullName:"Mihai Mares"}],equalEditorOne:{id:"190224",title:"Dr.",name:"Swee Hua Erin",middleName:null,surname:"Lim",slug:"swee-hua-erin-lim",fullName:"Swee Hua Erin Lim",profilePictureURL:"https://mts.intechopen.com/storage/users/190224/images/system/190224.png",biography:"Dr. Erin Lim is presently working as an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates and is affiliated as an Associate Professor to Perdana University-Royal College of Surgeons in Ireland, Selangor, Malaysia. She obtained her Ph.D. from Universiti Putra Malaysia in 2010 with a National Science Fellowship awarded from the Ministry of Science, Technology and Innovation Malaysia and has been actively involved in research ever since. Her main research interests include analysis of carriage and transmission of multidrug resistant bacteria in non-conventional settings, besides an interest in natural products for antimicrobial testing. She is heavily involved in the elucidation of mechanisms of reversal of resistance in bacteria in addition to investigating the immunological analyses of diseases, development of vaccination and treatment models in animals. She hopes her work will support the discovery of therapeutics in the clinical setting and assist in the combat against the burden of antibiotic resistance.",institutionString:"Abu Dhabi Women’s College",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Perdana University",institutionURL:null,country:{name:"Malaysia"}}},equalEditorTwo:{id:"221544",title:"Dr.",name:"Kok-Song",middleName:null,surname:"Lai",slug:"kok-song-lai",fullName:"Kok-Song Lai",profilePictureURL:"https://mts.intechopen.com/storage/users/221544/images/system/221544.jpeg",biography:"Dr. Lai Kok Song is an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates. He obtained his Ph.D. in Biological Sciences from Nara Institute of Science and Technology, Japan in 2012. Prior to his academic appointment, Dr. Lai worked as a Senior Scientist at the Ministry of Science, Technology and Innovation, Malaysia. His current research areas include antimicrobial resistance and plant-pathogen interaction. His particular interest lies in the study of the antimicrobial mechanism via membrane disruption of essential oils against multi-drug resistance bacteria through various biochemical, molecular and proteomic approaches. Ultimately, he hopes to uncover and determine novel biomarkers related to antibiotic resistance that can be developed into new therapeutic strategies.",institutionString:"Higher Colleges of Technology",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"8",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Higher Colleges of Technology",institutionURL:null,country:{name:"United Arab Emirates"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10020",title:"Operations Management",subtitle:"Emerging Trend in the Digital Era",isOpenForSubmission:!1,hash:"526f0dbdc7e4d85b82ce8383ab894b4c",slug:"operations-management-emerging-trend-in-the-digital-era",bookSignature:"Antonella Petrillo, Fabio De Felice, Germano Lambert-Torres and Erik Bonaldi",coverURL:"https://cdn.intechopen.com/books/images_new/10020.jpg",editors:[{id:"181603",title:"Dr.",name:"Antonella",middleName:null,surname:"Petrillo",slug:"antonella-petrillo",fullName:"Antonella Petrillo"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9560",title:"Creativity",subtitle:"A Force to Innovation",isOpenForSubmission:!1,hash:"58f740bc17807d5d88d647c525857b11",slug:"creativity-a-force-to-innovation",bookSignature:"Pooja Jain",coverURL:"https://cdn.intechopen.com/books/images_new/9560.jpg",editors:[{id:"316765",title:"Dr.",name:"Pooja",middleName:null,surname:"Jain",slug:"pooja-jain",fullName:"Pooja Jain"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10192",title:"Background and Management of Muscular Atrophy",subtitle:null,isOpenForSubmission:!1,hash:"eca24028d89912b5efea56e179dff089",slug:"background-and-management-of-muscular-atrophy",bookSignature:"Julianna Cseri",coverURL:"https://cdn.intechopen.com/books/images_new/10192.jpg",editors:[{id:"135579",title:"Dr.",name:"Julianna",middleName:null,surname:"Cseri",slug:"julianna-cseri",fullName:"Julianna Cseri"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9243",title:"Coastal Environments",subtitle:null,isOpenForSubmission:!1,hash:"8e05e5f631e935eef366980f2e28295d",slug:"coastal-environments",bookSignature:"Yuanzhi Zhang and X. San Liang",coverURL:"https://cdn.intechopen.com/books/images_new/9243.jpg",editors:[{id:"77597",title:"Prof.",name:"Yuanzhi",middleName:null,surname:"Zhang",slug:"yuanzhi-zhang",fullName:"Yuanzhi Zhang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9385",title:"Renewable Energy",subtitle:"Technologies and Applications",isOpenForSubmission:!1,hash:"a6b446d19166f17f313008e6c056f3d8",slug:"renewable-energy-technologies-and-applications",bookSignature:"Tolga Taner, Archana Tiwari and Taha Selim Ustun",coverURL:"https://cdn.intechopen.com/books/images_new/9385.jpg",editors:[{id:"197240",title:"Associate Prof.",name:"Tolga",middleName:null,surname:"Taner",slug:"tolga-taner",fullName:"Tolga Taner"}],equalEditorOne:{id:"186791",title:"Dr.",name:"Archana",middleName:null,surname:"Tiwari",slug:"archana-tiwari",fullName:"Archana Tiwari",profilePictureURL:"https://mts.intechopen.com/storage/users/186791/images/system/186791.jpg",biography:"Dr. Archana Tiwari is Associate Professor at Amity University, India. Her research interests include renewable sources of energy from microalgae and further utilizing the residual biomass for the generation of value-added products, bioremediation through microalgae and microbial consortium, antioxidative enzymes and stress, and nutraceuticals from microalgae. She has been working on algal biotechnology for the last two decades. She has published her research in many international journals and has authored many books and chapters with renowned publishing houses. She has also delivered talks as an invited speaker at many national and international conferences. Dr. Tiwari is the recipient of several awards including Researcher of the Year and Distinguished Scientist.",institutionString:"Amity University",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"1",institution:{name:"Amity University",institutionURL:null,country:{name:"India"}}},equalEditorTwo:{id:"197609",title:"Prof.",name:"Taha Selim",middleName:null,surname:"Ustun",slug:"taha-selim-ustun",fullName:"Taha Selim Ustun",profilePictureURL:"https://mts.intechopen.com/storage/users/197609/images/system/197609.jpeg",biography:"Dr. Taha Selim Ustun received a Ph.D. in Electrical Engineering from Victoria University, Melbourne, Australia. He is a researcher with the Fukushima Renewable Energy Institute, AIST (FREA), where he leads the Smart Grid Cybersecurity Laboratory. Prior to that, he was a faculty member with the School of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. His current research interests include power systems protection, communication in power networks, distributed generation, microgrids, electric vehicle integration, and cybersecurity in smart grids. He serves on the editorial boards of IEEE Access, IEEE Transactions on Industrial Informatics, Energies, Electronics, Electricity, World Electric Vehicle and Information journals. Dr. Ustun is a member of the IEEE 2004 and 2800, IEC Renewable Energy Management WG 8, and IEC TC 57 WG17. He has been invited to run specialist courses in Africa, India, and China. He has delivered talks for the Qatar Foundation, the World Energy Council, the Waterloo Global Science Initiative, and the European Union Energy Initiative (EUEI). His research has attracted funding from prestigious programs in Japan, Australia, the European Union, and North America.",institutionString:"Fukushima Renewable Energy Institute, AIST (FREA)",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"National Institute of Advanced Industrial Science and Technology",institutionURL:null,country:{name:"Japan"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8985",title:"Natural Resources Management and Biological Sciences",subtitle:null,isOpenForSubmission:!1,hash:"5c2e219a6c021a40b5a20c041dea88c4",slug:"natural-resources-management-and-biological-sciences",bookSignature:"Edward R. Rhodes and Humood Naser",coverURL:"https://cdn.intechopen.com/books/images_new/8985.jpg",editors:[{id:"280886",title:"Prof.",name:"Edward R",middleName:null,surname:"Rhodes",slug:"edward-r-rhodes",fullName:"Edward R Rhodes"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10065",title:"Wavelet Theory",subtitle:null,isOpenForSubmission:!1,hash:"d8868e332169597ba2182d9b004d60de",slug:"wavelet-theory",bookSignature:"Somayeh Mohammady",coverURL:"https://cdn.intechopen.com/books/images_new/10065.jpg",editors:[{id:"109280",title:"Dr.",name:"Somayeh",middleName:null,surname:"Mohammady",slug:"somayeh-mohammady",fullName:"Somayeh Mohammady"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9644",title:"Glaciers and the Polar Environment",subtitle:null,isOpenForSubmission:!1,hash:"e8cfdc161794e3753ced54e6ff30873b",slug:"glaciers-and-the-polar-environment",bookSignature:"Masaki Kanao, Danilo Godone and Niccolò Dematteis",coverURL:"https://cdn.intechopen.com/books/images_new/9644.jpg",editors:[{id:"51959",title:"Dr.",name:"Masaki",middleName:null,surname:"Kanao",slug:"masaki-kanao",fullName:"Masaki Kanao"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9550",title:"Entrepreneurship",subtitle:"Contemporary Issues",isOpenForSubmission:!1,hash:"9b4ac1ee5b743abf6f88495452b1e5e7",slug:"entrepreneurship-contemporary-issues",bookSignature:"Mladen Turuk",coverURL:"https://cdn.intechopen.com/books/images_new/9550.jpg",editors:[{id:"319755",title:"Prof.",name:"Mladen",middleName:null,surname:"Turuk",slug:"mladen-turuk",fullName:"Mladen Turuk"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9027",title:"Human Blood Group Systems and Haemoglobinopathies",subtitle:null,isOpenForSubmission:!1,hash:"d00d8e40b11cfb2547d1122866531c7e",slug:"human-blood-group-systems-and-haemoglobinopathies",bookSignature:"Osaro Erhabor and Anjana Munshi",coverURL:"https://cdn.intechopen.com/books/images_new/9027.jpg",editors:[{id:"35140",title:null,name:"Osaro",middleName:null,surname:"Erhabor",slug:"osaro-erhabor",fullName:"Osaro Erhabor"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8558",title:"Aerodynamics",subtitle:null,isOpenForSubmission:!1,hash:"db7263fc198dfb539073ba0260a7f1aa",slug:"aerodynamics",bookSignature:"Mofid Gorji-Bandpy and Aly-Mousaad Aly",coverURL:"https://cdn.intechopen.com/books/images_new/8558.jpg",editors:[{id:"35542",title:"Prof.",name:"Mofid",middleName:null,surname:"Gorji-Bandpy",slug:"mofid-gorji-bandpy",fullName:"Mofid Gorji-Bandpy"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],offset:12,limit:12,total:5249},hotBookTopics:{hotBooks:[],offset:0,limit:12,total:null},publish:{},publishingProposal:{success:null,errors:{}},books:{featuredBooks:[{type:"book",id:"9521",title:"Antimicrobial Resistance",subtitle:"A One Health Perspective",isOpenForSubmission:!1,hash:"30949e78832e1afba5606634b52056ab",slug:"antimicrobial-resistance-a-one-health-perspective",bookSignature:"Mihai Mareș, Swee Hua Erin Lim, Kok-Song Lai and Romeo-Teodor Cristina",coverURL:"https://cdn.intechopen.com/books/images_new/9521.jpg",editors:[{id:"88785",title:"Prof.",name:"Mihai",middleName:null,surname:"Mares",slug:"mihai-mares",fullName:"Mihai Mares"}],equalEditorOne:{id:"190224",title:"Dr.",name:"Swee Hua Erin",middleName:null,surname:"Lim",slug:"swee-hua-erin-lim",fullName:"Swee Hua Erin Lim",profilePictureURL:"https://mts.intechopen.com/storage/users/190224/images/system/190224.png",biography:"Dr. Erin Lim is presently working as an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates and is affiliated as an Associate Professor to Perdana University-Royal College of Surgeons in Ireland, Selangor, Malaysia. She obtained her Ph.D. from Universiti Putra Malaysia in 2010 with a National Science Fellowship awarded from the Ministry of Science, Technology and Innovation Malaysia and has been actively involved in research ever since. Her main research interests include analysis of carriage and transmission of multidrug resistant bacteria in non-conventional settings, besides an interest in natural products for antimicrobial testing. She is heavily involved in the elucidation of mechanisms of reversal of resistance in bacteria in addition to investigating the immunological analyses of diseases, development of vaccination and treatment models in animals. She hopes her work will support the discovery of therapeutics in the clinical setting and assist in the combat against the burden of antibiotic resistance.",institutionString:"Abu Dhabi Women’s College",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Perdana University",institutionURL:null,country:{name:"Malaysia"}}},equalEditorTwo:{id:"221544",title:"Dr.",name:"Kok-Song",middleName:null,surname:"Lai",slug:"kok-song-lai",fullName:"Kok-Song Lai",profilePictureURL:"https://mts.intechopen.com/storage/users/221544/images/system/221544.jpeg",biography:"Dr. Lai Kok Song is an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates. He obtained his Ph.D. in Biological Sciences from Nara Institute of Science and Technology, Japan in 2012. Prior to his academic appointment, Dr. Lai worked as a Senior Scientist at the Ministry of Science, Technology and Innovation, Malaysia. His current research areas include antimicrobial resistance and plant-pathogen interaction. His particular interest lies in the study of the antimicrobial mechanism via membrane disruption of essential oils against multi-drug resistance bacteria through various biochemical, molecular and proteomic approaches. Ultimately, he hopes to uncover and determine novel biomarkers related to antibiotic resistance that can be developed into new therapeutic strategies.",institutionString:"Higher Colleges of Technology",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"8",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Higher Colleges of Technology",institutionURL:null,country:{name:"United Arab Emirates"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10020",title:"Operations Management",subtitle:"Emerging Trend in the Digital Era",isOpenForSubmission:!1,hash:"526f0dbdc7e4d85b82ce8383ab894b4c",slug:"operations-management-emerging-trend-in-the-digital-era",bookSignature:"Antonella Petrillo, Fabio De Felice, Germano Lambert-Torres and Erik Bonaldi",coverURL:"https://cdn.intechopen.com/books/images_new/10020.jpg",editors:[{id:"181603",title:"Dr.",name:"Antonella",middleName:null,surname:"Petrillo",slug:"antonella-petrillo",fullName:"Antonella Petrillo"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9560",title:"Creativity",subtitle:"A Force to Innovation",isOpenForSubmission:!1,hash:"58f740bc17807d5d88d647c525857b11",slug:"creativity-a-force-to-innovation",bookSignature:"Pooja Jain",coverURL:"https://cdn.intechopen.com/books/images_new/9560.jpg",editors:[{id:"316765",title:"Dr.",name:"Pooja",middleName:null,surname:"Jain",slug:"pooja-jain",fullName:"Pooja Jain"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10192",title:"Background and Management of Muscular Atrophy",subtitle:null,isOpenForSubmission:!1,hash:"eca24028d89912b5efea56e179dff089",slug:"background-and-management-of-muscular-atrophy",bookSignature:"Julianna Cseri",coverURL:"https://cdn.intechopen.com/books/images_new/10192.jpg",editors:[{id:"135579",title:"Dr.",name:"Julianna",middleName:null,surname:"Cseri",slug:"julianna-cseri",fullName:"Julianna Cseri"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9243",title:"Coastal Environments",subtitle:null,isOpenForSubmission:!1,hash:"8e05e5f631e935eef366980f2e28295d",slug:"coastal-environments",bookSignature:"Yuanzhi Zhang and X. San Liang",coverURL:"https://cdn.intechopen.com/books/images_new/9243.jpg",editors:[{id:"77597",title:"Prof.",name:"Yuanzhi",middleName:null,surname:"Zhang",slug:"yuanzhi-zhang",fullName:"Yuanzhi Zhang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9385",title:"Renewable Energy",subtitle:"Technologies and Applications",isOpenForSubmission:!1,hash:"a6b446d19166f17f313008e6c056f3d8",slug:"renewable-energy-technologies-and-applications",bookSignature:"Tolga Taner, Archana Tiwari and Taha Selim Ustun",coverURL:"https://cdn.intechopen.com/books/images_new/9385.jpg",editors:[{id:"197240",title:"Associate Prof.",name:"Tolga",middleName:null,surname:"Taner",slug:"tolga-taner",fullName:"Tolga Taner"}],equalEditorOne:{id:"186791",title:"Dr.",name:"Archana",middleName:null,surname:"Tiwari",slug:"archana-tiwari",fullName:"Archana Tiwari",profilePictureURL:"https://mts.intechopen.com/storage/users/186791/images/system/186791.jpg",biography:"Dr. Archana Tiwari is Associate Professor at Amity University, India. Her research interests include renewable sources of energy from microalgae and further utilizing the residual biomass for the generation of value-added products, bioremediation through microalgae and microbial consortium, antioxidative enzymes and stress, and nutraceuticals from microalgae. She has been working on algal biotechnology for the last two decades. She has published her research in many international journals and has authored many books and chapters with renowned publishing houses. She has also delivered talks as an invited speaker at many national and international conferences. Dr. Tiwari is the recipient of several awards including Researcher of the Year and Distinguished Scientist.",institutionString:"Amity University",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"1",institution:{name:"Amity University",institutionURL:null,country:{name:"India"}}},equalEditorTwo:{id:"197609",title:"Prof.",name:"Taha Selim",middleName:null,surname:"Ustun",slug:"taha-selim-ustun",fullName:"Taha Selim Ustun",profilePictureURL:"https://mts.intechopen.com/storage/users/197609/images/system/197609.jpeg",biography:"Dr. Taha Selim Ustun received a Ph.D. in Electrical Engineering from Victoria University, Melbourne, Australia. He is a researcher with the Fukushima Renewable Energy Institute, AIST (FREA), where he leads the Smart Grid Cybersecurity Laboratory. Prior to that, he was a faculty member with the School of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA. His current research interests include power systems protection, communication in power networks, distributed generation, microgrids, electric vehicle integration, and cybersecurity in smart grids. He serves on the editorial boards of IEEE Access, IEEE Transactions on Industrial Informatics, Energies, Electronics, Electricity, World Electric Vehicle and Information journals. Dr. Ustun is a member of the IEEE 2004 and 2800, IEC Renewable Energy Management WG 8, and IEC TC 57 WG17. He has been invited to run specialist courses in Africa, India, and China. He has delivered talks for the Qatar Foundation, the World Energy Council, the Waterloo Global Science Initiative, and the European Union Energy Initiative (EUEI). His research has attracted funding from prestigious programs in Japan, Australia, the European Union, and North America.",institutionString:"Fukushima Renewable Energy Institute, AIST (FREA)",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"National Institute of Advanced Industrial Science and Technology",institutionURL:null,country:{name:"Japan"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"8985",title:"Natural Resources Management and Biological Sciences",subtitle:null,isOpenForSubmission:!1,hash:"5c2e219a6c021a40b5a20c041dea88c4",slug:"natural-resources-management-and-biological-sciences",bookSignature:"Edward R. Rhodes and Humood Naser",coverURL:"https://cdn.intechopen.com/books/images_new/8985.jpg",editors:[{id:"280886",title:"Prof.",name:"Edward R",middleName:null,surname:"Rhodes",slug:"edward-r-rhodes",fullName:"Edward R Rhodes"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"10065",title:"Wavelet Theory",subtitle:null,isOpenForSubmission:!1,hash:"d8868e332169597ba2182d9b004d60de",slug:"wavelet-theory",bookSignature:"Somayeh Mohammady",coverURL:"https://cdn.intechopen.com/books/images_new/10065.jpg",editors:[{id:"109280",title:"Dr.",name:"Somayeh",middleName:null,surname:"Mohammady",slug:"somayeh-mohammady",fullName:"Somayeh Mohammady"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9644",title:"Glaciers and the Polar Environment",subtitle:null,isOpenForSubmission:!1,hash:"e8cfdc161794e3753ced54e6ff30873b",slug:"glaciers-and-the-polar-environment",bookSignature:"Masaki Kanao, Danilo Godone and Niccolò Dematteis",coverURL:"https://cdn.intechopen.com/books/images_new/9644.jpg",editors:[{id:"51959",title:"Dr.",name:"Masaki",middleName:null,surname:"Kanao",slug:"masaki-kanao",fullName:"Masaki Kanao"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"9550",title:"Entrepreneurship",subtitle:"Contemporary Issues",isOpenForSubmission:!1,hash:"9b4ac1ee5b743abf6f88495452b1e5e7",slug:"entrepreneurship-contemporary-issues",bookSignature:"Mladen Turuk",coverURL:"https://cdn.intechopen.com/books/images_new/9550.jpg",editors:[{id:"319755",title:"Prof.",name:"Mladen",middleName:null,surname:"Turuk",slug:"mladen-turuk",fullName:"Mladen Turuk"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],latestBooks:[{type:"book",id:"9243",title:"Coastal Environments",subtitle:null,isOpenForSubmission:!1,hash:"8e05e5f631e935eef366980f2e28295d",slug:"coastal-environments",bookSignature:"Yuanzhi Zhang and X. San Liang",coverURL:"https://cdn.intechopen.com/books/images_new/9243.jpg",editedByType:"Edited by",editors:[{id:"77597",title:"Prof.",name:"Yuanzhi",middleName:null,surname:"Zhang",slug:"yuanzhi-zhang",fullName:"Yuanzhi Zhang"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10020",title:"Operations Management",subtitle:"Emerging Trend in the Digital Era",isOpenForSubmission:!1,hash:"526f0dbdc7e4d85b82ce8383ab894b4c",slug:"operations-management-emerging-trend-in-the-digital-era",bookSignature:"Antonella Petrillo, Fabio De Felice, Germano Lambert-Torres and Erik Bonaldi",coverURL:"https://cdn.intechopen.com/books/images_new/10020.jpg",editedByType:"Edited by",editors:[{id:"181603",title:"Dr.",name:"Antonella",middleName:null,surname:"Petrillo",slug:"antonella-petrillo",fullName:"Antonella Petrillo"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9521",title:"Antimicrobial Resistance",subtitle:"A One Health Perspective",isOpenForSubmission:!1,hash:"30949e78832e1afba5606634b52056ab",slug:"antimicrobial-resistance-a-one-health-perspective",bookSignature:"Mihai Mareș, Swee Hua Erin Lim, Kok-Song Lai and Romeo-Teodor Cristina",coverURL:"https://cdn.intechopen.com/books/images_new/9521.jpg",editedByType:"Edited by",editors:[{id:"88785",title:"Prof.",name:"Mihai",middleName:null,surname:"Mares",slug:"mihai-mares",fullName:"Mihai Mares"}],equalEditorOne:{id:"190224",title:"Dr.",name:"Swee Hua Erin",middleName:null,surname:"Lim",slug:"swee-hua-erin-lim",fullName:"Swee Hua Erin Lim",profilePictureURL:"https://mts.intechopen.com/storage/users/190224/images/system/190224.png",biography:"Dr. Erin Lim is presently working as an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates and is affiliated as an Associate Professor to Perdana University-Royal College of Surgeons in Ireland, Selangor, Malaysia. She obtained her Ph.D. from Universiti Putra Malaysia in 2010 with a National Science Fellowship awarded from the Ministry of Science, Technology and Innovation Malaysia and has been actively involved in research ever since. Her main research interests include analysis of carriage and transmission of multidrug resistant bacteria in non-conventional settings, besides an interest in natural products for antimicrobial testing. She is heavily involved in the elucidation of mechanisms of reversal of resistance in bacteria in addition to investigating the immunological analyses of diseases, development of vaccination and treatment models in animals. She hopes her work will support the discovery of therapeutics in the clinical setting and assist in the combat against the burden of antibiotic resistance.",institutionString:"Abu Dhabi Women’s College",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"3",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Perdana University",institutionURL:null,country:{name:"Malaysia"}}},equalEditorTwo:{id:"221544",title:"Dr.",name:"Kok-Song",middleName:null,surname:"Lai",slug:"kok-song-lai",fullName:"Kok-Song Lai",profilePictureURL:"https://mts.intechopen.com/storage/users/221544/images/system/221544.jpeg",biography:"Dr. Lai Kok Song is an Assistant Professor in the Division of Health Sciences, Abu Dhabi Women\\'s College, Higher Colleges of Technology in Abu Dhabi, United Arab Emirates. He obtained his Ph.D. in Biological Sciences from Nara Institute of Science and Technology, Japan in 2012. Prior to his academic appointment, Dr. Lai worked as a Senior Scientist at the Ministry of Science, Technology and Innovation, Malaysia. His current research areas include antimicrobial resistance and plant-pathogen interaction. His particular interest lies in the study of the antimicrobial mechanism via membrane disruption of essential oils against multi-drug resistance bacteria through various biochemical, molecular and proteomic approaches. Ultimately, he hopes to uncover and determine novel biomarkers related to antibiotic resistance that can be developed into new therapeutic strategies.",institutionString:"Higher Colleges of Technology",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"8",totalChapterViews:"0",totalEditedBooks:"0",institution:{name:"Higher Colleges of Technology",institutionURL:null,country:{name:"United Arab Emirates"}}},equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9560",title:"Creativity",subtitle:"A Force to Innovation",isOpenForSubmission:!1,hash:"58f740bc17807d5d88d647c525857b11",slug:"creativity-a-force-to-innovation",bookSignature:"Pooja Jain",coverURL:"https://cdn.intechopen.com/books/images_new/9560.jpg",editedByType:"Edited by",editors:[{id:"316765",title:"Dr.",name:"Pooja",middleName:null,surname:"Jain",slug:"pooja-jain",fullName:"Pooja Jain"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9669",title:"Recent Advances in Rice Research",subtitle:null,isOpenForSubmission:!1,hash:"12b06cc73e89af1e104399321cc16a75",slug:"recent-advances-in-rice-research",bookSignature:"Mahmood-ur- Rahman Ansari",coverURL:"https://cdn.intechopen.com/books/images_new/9669.jpg",editedByType:"Edited by",editors:[{id:"185476",title:"Dr.",name:"Mahmood-Ur-",middleName:null,surname:"Rahman Ansari",slug:"mahmood-ur-rahman-ansari",fullName:"Mahmood-Ur- Rahman Ansari"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10192",title:"Background and Management of Muscular Atrophy",subtitle:null,isOpenForSubmission:!1,hash:"eca24028d89912b5efea56e179dff089",slug:"background-and-management-of-muscular-atrophy",bookSignature:"Julianna Cseri",coverURL:"https://cdn.intechopen.com/books/images_new/10192.jpg",editedByType:"Edited by",editors:[{id:"135579",title:"Dr.",name:"Julianna",middleName:null,surname:"Cseri",slug:"julianna-cseri",fullName:"Julianna Cseri"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9550",title:"Entrepreneurship",subtitle:"Contemporary Issues",isOpenForSubmission:!1,hash:"9b4ac1ee5b743abf6f88495452b1e5e7",slug:"entrepreneurship-contemporary-issues",bookSignature:"Mladen Turuk",coverURL:"https://cdn.intechopen.com/books/images_new/9550.jpg",editedByType:"Edited by",editors:[{id:"319755",title:"Prof.",name:"Mladen",middleName:null,surname:"Turuk",slug:"mladen-turuk",fullName:"Mladen Turuk"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"10065",title:"Wavelet Theory",subtitle:null,isOpenForSubmission:!1,hash:"d8868e332169597ba2182d9b004d60de",slug:"wavelet-theory",bookSignature:"Somayeh Mohammady",coverURL:"https://cdn.intechopen.com/books/images_new/10065.jpg",editedByType:"Edited by",editors:[{id:"109280",title:"Dr.",name:"Somayeh",middleName:null,surname:"Mohammady",slug:"somayeh-mohammady",fullName:"Somayeh Mohammady"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9313",title:"Clay Science and Technology",subtitle:null,isOpenForSubmission:!1,hash:"6fa7e70396ff10620e032bb6cfa6fb72",slug:"clay-science-and-technology",bookSignature:"Gustavo Morari Do Nascimento",coverURL:"https://cdn.intechopen.com/books/images_new/9313.jpg",editedByType:"Edited by",editors:[{id:"7153",title:"Prof.",name:"Gustavo",middleName:null,surname:"Morari Do Nascimento",slug:"gustavo-morari-do-nascimento",fullName:"Gustavo Morari Do Nascimento"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9888",title:"Nuclear Power Plants",subtitle:"The Processes from the Cradle to the Grave",isOpenForSubmission:!1,hash:"c2c8773e586f62155ab8221ebb72a849",slug:"nuclear-power-plants-the-processes-from-the-cradle-to-the-grave",bookSignature:"Nasser Awwad",coverURL:"https://cdn.intechopen.com/books/images_new/9888.jpg",editedByType:"Edited by",editors:[{id:"145209",title:"Prof.",name:"Nasser",middleName:"S",surname:"Awwad",slug:"nasser-awwad",fullName:"Nasser Awwad"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},subject:{topic:{id:"994",title:"Traumatology",slug:"traumatology",parent:{title:"Critical Care Medicine",slug:"critical-care-medicine"},numberOfBooks:5,numberOfAuthorsAndEditors:132,numberOfWosCitations:55,numberOfCrossrefCitations:44,numberOfDimensionsCitations:101,videoUrl:null,fallbackUrl:null,description:null},booksByTopicFilter:{topicSlug:"traumatology",sort:"-publishedDate",limit:12,offset:0},booksByTopicCollection:[{type:"book",id:"9066",title:"Wound Healing",subtitle:null,isOpenForSubmission:!1,hash:"a293ecd8c2655a402321dc30e0ffbf9a",slug:"wound-healing",bookSignature:"Muhammad Ahmad",coverURL:"https://cdn.intechopen.com/books/images_new/9066.jpg",editedByType:"Edited by",editors:[{id:"204257",title:"Dr.",name:"Muhammad",middleName:null,surname:"Ahmad",slug:"muhammad-ahmad",fullName:"Muhammad Ahmad"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7046",title:"Wound Healing",subtitle:"Current Perspectives",isOpenForSubmission:!1,hash:"fa7b870ad29ce1dfcf6faeafdc060309",slug:"wound-healing-current-perspectives",bookSignature:"Kamil Hakan Dogan",coverURL:"https://cdn.intechopen.com/books/images_new/7046.jpg",editedByType:"Edited by",editors:[{id:"30612",title:"Prof.",name:"Kamil Hakan",middleName:null,surname:"Dogan",slug:"kamil-hakan-dogan",fullName:"Kamil Hakan Dogan"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6662",title:"Trauma Surgery",subtitle:null,isOpenForSubmission:!1,hash:"9721b9ac98bf237058cafd0a0303bdbc",slug:"trauma-surgery",bookSignature:"Ozgur Karcioglu and Hakan Topacoglu",coverURL:"https://cdn.intechopen.com/books/images_new/6662.jpg",editedByType:"Edited by",editors:[{id:"221195",title:"Dr.",name:"Ozgur",middleName:null,surname:"Karcioglu",slug:"ozgur-karcioglu",fullName:"Ozgur Karcioglu"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6069",title:"Essentials of Spinal Cord Injury Medicine",subtitle:null,isOpenForSubmission:!1,hash:"f0a49e24ebfbb9ed7d02f7daab9b30f6",slug:"essentials-of-spinal-cord-injury-medicine",bookSignature:"Yannis Dionyssiotis",coverURL:"https://cdn.intechopen.com/books/images_new/6069.jpg",editedByType:"Edited by",editors:[{id:"76883",title:"PhD.",name:"Yannis",middleName:null,surname:"Dionyssiotis",slug:"yannis-dionyssiotis",fullName:"Yannis Dionyssiotis"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"5290",title:"Wound Healing",subtitle:"New insights into Ancient Challenges",isOpenForSubmission:!1,hash:"a6c479ab3fea0a9b7051d2a8478c91c3",slug:"wound-healing-new-insights-into-ancient-challenges",bookSignature:"Vlad Adrian Alexandrescu",coverURL:"https://cdn.intechopen.com/books/images_new/5290.jpg",editedByType:"Edited by",editors:[{id:"66358",title:"Ph.D.",name:"Vlad",middleName:"Adrian",surname:"Alexandrescu",slug:"vlad-alexandrescu",fullName:"Vlad Alexandrescu"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],booksByTopicTotal:5,mostCitedChapters:[{id:"50983",doi:"10.5772/63961",title:"Antimicrobial Dressings for Improving Wound Healing",slug:"antimicrobial-dressings-for-improving-wound-healing",totalDownloads:3705,totalCrossrefCites:5,totalDimensionsCites:21,book:{slug:"wound-healing-new-insights-into-ancient-challenges",title:"Wound Healing",fullTitle:"Wound Healing - New insights into Ancient Challenges"},signatures:"Omar Sarheed, Asif Ahmed, Douha Shouqair and Joshua Boateng",authors:[{id:"183108",title:"Dr.",name:"Joshua",middleName:null,surname:"Boateng",slug:"joshua-boateng",fullName:"Joshua Boateng"},{id:"183399",title:"Dr.",name:"Omar",middleName:null,surname:"Sarheed",slug:"omar-sarheed",fullName:"Omar Sarheed"},{id:"188082",title:"Mr.",name:"Asif",middleName:null,surname:"Ahmed",slug:"asif-ahmed",fullName:"Asif Ahmed"},{id:"188083",title:"Ms.",name:"Douha",middleName:null,surname:"Shouqair",slug:"douha-shouqair",fullName:"Douha Shouqair"}]},{id:"51825",doi:"10.5772/64611",title:"Roles of Matrix Metalloproteinases in Cutaneous Wound Healing",slug:"roles-of-matrix-metalloproteinases-in-cutaneous-wound-healing",totalDownloads:2740,totalCrossrefCites:8,totalDimensionsCites:14,book:{slug:"wound-healing-new-insights-into-ancient-challenges",title:"Wound Healing",fullTitle:"Wound Healing - New insights into Ancient Challenges"},signatures:"Trung T. Nguyen, Shahriar Mobashery and Mayland Chang",authors:[{id:"183405",title:"Prof.",name:"Mayland",middleName:null,surname:"Chang",slug:"mayland-chang",fullName:"Mayland Chang"},{id:"191152",title:"Mr.",name:"Trung",middleName:null,surname:"Nguyen",slug:"trung-nguyen",fullName:"Trung Nguyen"},{id:"191153",title:"Prof.",name:"Shahriar",middleName:null,surname:"Mobashery",slug:"shahriar-mobashery",fullName:"Shahriar Mobashery"}]},{id:"63675",doi:"10.5772/intechopen.81208",title:"Wound Healing: Contributions from Plant Secondary Metabolite Antioxidants",slug:"wound-healing-contributions-from-plant-secondary-metabolite-antioxidants",totalDownloads:685,totalCrossrefCites:1,totalDimensionsCites:6,book:{slug:"wound-healing-current-perspectives",title:"Wound Healing",fullTitle:"Wound Healing - Current Perspectives"},signatures:"Victor Y.A. Barku",authors:[{id:"261027",title:"Prof.",name:"Victor Y. A.",middleName:null,surname:"Barku",slug:"victor-y.-a.-barku",fullName:"Victor Y. A. Barku"}]}],mostDownloadedChaptersLast30Days:[{id:"60520",title:"Maxillofacial Fractures: From Diagnosis to Treatment",slug:"maxillofacial-fractures-from-diagnosis-to-treatment",totalDownloads:1791,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"trauma-surgery",title:"Trauma Surgery",fullTitle:"Trauma Surgery"},signatures:"Mohammad Esmaeelinejad",authors:[{id:"172188",title:"Dr.",name:"Mohammad",middleName:null,surname:"Esmaeelinejad",slug:"mohammad-esmaeelinejad",fullName:"Mohammad Esmaeelinejad"}]},{id:"51825",title:"Roles of Matrix Metalloproteinases in Cutaneous Wound Healing",slug:"roles-of-matrix-metalloproteinases-in-cutaneous-wound-healing",totalDownloads:2743,totalCrossrefCites:8,totalDimensionsCites:15,book:{slug:"wound-healing-new-insights-into-ancient-challenges",title:"Wound Healing",fullTitle:"Wound Healing - New insights into Ancient Challenges"},signatures:"Trung T. Nguyen, Shahriar Mobashery and Mayland Chang",authors:[{id:"183405",title:"Prof.",name:"Mayland",middleName:null,surname:"Chang",slug:"mayland-chang",fullName:"Mayland Chang"},{id:"191152",title:"Mr.",name:"Trung",middleName:null,surname:"Nguyen",slug:"trung-nguyen",fullName:"Trung Nguyen"},{id:"191153",title:"Prof.",name:"Shahriar",middleName:null,surname:"Mobashery",slug:"shahriar-mobashery",fullName:"Shahriar Mobashery"}]},{id:"51223",title:"Medicinal Plants and Natural Products with Demonstrated Wound Healing Properties",slug:"medicinal-plants-and-natural-products-with-demonstrated-wound-healing-properties",totalDownloads:2807,totalCrossrefCites:1,totalDimensionsCites:3,book:{slug:"wound-healing-new-insights-into-ancient-challenges",title:"Wound Healing",fullTitle:"Wound Healing - New insights into Ancient Challenges"},signatures:"Christian Agyare, Emelia Oppong Bekoe, Yaw Duah Boakye,\nSusanna Oteng Dapaah, Theresa Appiah and Samuel Oppong\nBekoe",authors:[{id:"182058",title:"Dr.",name:"Christian",middleName:null,surname:"Agyare",slug:"christian-agyare",fullName:"Christian Agyare"},{id:"186987",title:"Dr.",name:"Yaw Duah",middleName:null,surname:"Boakye",slug:"yaw-duah-boakye",fullName:"Yaw Duah Boakye"},{id:"186988",title:"Ms.",name:"Susanna Oteng",middleName:null,surname:"Dapaah",slug:"susanna-oteng-dapaah",fullName:"Susanna Oteng Dapaah"},{id:"186989",title:"MSc.",name:"Theresa",middleName:null,surname:"Appiah",slug:"theresa-appiah",fullName:"Theresa Appiah"},{id:"186990",title:"Dr.",name:"Samuel Oppong",middleName:null,surname:"Bekoe",slug:"samuel-oppong-bekoe",fullName:"Samuel Oppong Bekoe"},{id:"186992",title:"Dr.",name:"Emelia Oppong",middleName:null,surname:"Bekoe",slug:"emelia-oppong-bekoe",fullName:"Emelia Oppong Bekoe"}]},{id:"63086",title:"Medicinal Plants in Wound Healing",slug:"medicinal-plants-in-wound-healing",totalDownloads:1701,totalCrossrefCites:0,totalDimensionsCites:2,book:{slug:"wound-healing-current-perspectives",title:"Wound Healing",fullTitle:"Wound Healing - Current Perspectives"},signatures:"Mohammad Reza Farahpour",authors:[{id:"253340",title:"Prof.",name:"Mohammadreza",middleName:null,surname:"Farahpour",slug:"mohammadreza-farahpour",fullName:"Mohammadreza Farahpour"}]},{id:"62998",title:"Biomarkers of Wound Healing",slug:"biomarkers-of-wound-healing",totalDownloads:890,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"wound-healing-current-perspectives",title:"Wound Healing",fullTitle:"Wound Healing - Current Perspectives"},signatures:"Christian Agyare, Newman Osafo and Yaw Duah Boakye",authors:[{id:"182058",title:"Dr.",name:"Christian",middleName:null,surname:"Agyare",slug:"christian-agyare",fullName:"Christian Agyare"},{id:"196452",title:"Dr.",name:"Newman",middleName:null,surname:"Osafo",slug:"newman-osafo",fullName:"Newman Osafo"},{id:"252789",title:"Dr.",name:"Yaw Duah",middleName:null,surname:"Boakye",slug:"yaw-duah-boakye",fullName:"Yaw Duah Boakye"}]},{id:"63082",title:"Abdominal Trauma",slug:"abdominal-trauma",totalDownloads:631,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"trauma-surgery",title:"Trauma Surgery",fullTitle:"Trauma Surgery"},signatures:"Göksu Afacan",authors:[{id:"236854",title:"M.D.",name:"Göksu",middleName:null,surname:"Afacan",slug:"goksu-afacan",fullName:"Göksu Afacan"}]},{id:"63308",title:"Autologous Platelet-Rich Plasma and Mesenchymal Stem Cells for the Treatment of Chronic Wounds",slug:"autologous-platelet-rich-plasma-and-mesenchymal-stem-cells-for-the-treatment-of-chronic-wounds",totalDownloads:1153,totalCrossrefCites:1,totalDimensionsCites:3,book:{slug:"wound-healing-current-perspectives",title:"Wound Healing",fullTitle:"Wound Healing - Current Perspectives"},signatures:"Peter A. Everts",authors:[{id:"256306",title:"Ph.D.",name:"Peter A.",middleName:null,surname:"Everts",slug:"peter-a.-everts",fullName:"Peter A. Everts"}]},{id:"66286",title:"From Tissue Repair to Tissue Regeneration",slug:"from-tissue-repair-to-tissue-regeneration",totalDownloads:1052,totalCrossrefCites:2,totalDimensionsCites:2,book:{slug:"wound-healing-current-perspectives",title:"Wound Healing",fullTitle:"Wound Healing - Current Perspectives"},signatures:"Aragona Salvatore Emanuele, Mereghetti Giada, Ferrari Alessio and\nGiorgio Ciprandi",authors:[{id:"247667",title:"Prof.",name:"Emanuele Salvatore",middleName:null,surname:"Aragona",slug:"emanuele-salvatore-aragona",fullName:"Emanuele Salvatore Aragona"}]},{id:"71904",title:"Modulation of Inflammatory Dynamics by Insulin to Promote Wound Recovery of Diabetic Ulcers",slug:"modulation-of-inflammatory-dynamics-by-insulin-to-promote-wound-recovery-of-diabetic-ulcers",totalDownloads:274,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"wound-healing",title:"Wound Healing",fullTitle:"Wound Healing"},signatures:"Pawandeep Kaur and Diptiman Choudhury",authors:null},{id:"51068",title:"A Potential Mechanism for Diabetic Wound Healing: Cutaneous Environmental Disorders",slug:"a-potential-mechanism-for-diabetic-wound-healing-cutaneous-environmental-disorders",totalDownloads:1432,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"wound-healing-new-insights-into-ancient-challenges",title:"Wound Healing",fullTitle:"Wound Healing - New insights into Ancient Challenges"},signatures:"Junna Ye, Ting Xie, Yiwen Niu, Liang Qiao, Ming Tian, Chun Qing\nand Shuliang Lu",authors:[{id:"182332",title:"Dr.",name:"Junna",middleName:null,surname:"Ye",slug:"junna-ye",fullName:"Junna Ye"}]}],onlineFirstChaptersFilter:{topicSlug:"traumatology",limit:3,offset:0},onlineFirstChaptersCollection:[],onlineFirstChaptersTotal:0},preDownload:{success:null,errors:{}},aboutIntechopen:{},privacyPolicy:{},peerReviewing:{},howOpenAccessPublishingWithIntechopenWorks:{},sponsorshipBooks:{sponsorshipBooks:[{type:"book",id:"10176",title:"Microgrids and Local Energy Systems",subtitle:null,isOpenForSubmission:!0,hash:"c32b4a5351a88f263074b0d0ca813a9c",slug:null,bookSignature:"Prof. Nick Jenkins",coverURL:"https://cdn.intechopen.com/books/images_new/10176.jpg",editedByType:null,editors:[{id:"55219",title:"Prof.",name:"Nick",middleName:null,surname:"Jenkins",slug:"nick-jenkins",fullName:"Nick Jenkins"}],equalEditorOne:null,equalEditorTwo:null,equalEditorThree:null,productType:{id:"1",chapterContentType:"chapter"}}],offset:8,limit:8,total:1},route:{name:"profile.detail",path:"/profiles/138492/dragica-maja-smrke",hash:"",query:{},params:{id:"138492",slug:"dragica-maja-smrke"},fullPath:"/profiles/138492/dragica-maja-smrke",meta:{},from:{name:null,path:"/",hash:"",query:{},params:{},fullPath:"/",meta:{}}}},function(){var e;(e=document.currentScript||document.scripts[document.scripts.length-1]).parentNode.removeChild(e)}()