Studying the activity of electrocatalysts towards ORR in comparison with commercial Pt/C, PtRu/C and PtRu/TiO2.
\r\n\tTopics that are welcome in the book address challenges that are not yet fully described in existing Baltic Sea compilations, but are present in scientific literature for some time.
",isbn:"978-1-78984-683-6",printIsbn:"978-1-78984-682-9",doi:null,price:0,slug:null,numberOfPages:0,isOpenForSubmission:!1,hash:"61d96e65b2fc43a8c2c681cb2c353e02",bookSignature:"Dr. Magdalena Bełdowska and Dr. Jacek Bełdowski",publishedDate:null,coverURL:"https://cdn.intechopen.com/books/images_new/8761.jpg",keywords:"Wrecks, Toxic Substances, Microplastics, Endocrine Disrupting Chemicals, Pharmaceuticals, Biomagnification, Bioacumulation, Fisheries, Icing Changes, Elongated Vegetative Season, Biodiversity, Shipping",numberOfDownloads:null,numberOfWosCitations:0,numberOfCrossrefCitations:0,numberOfDimensionsCitations:null,numberOfTotalCitations:null,isAvailableForWebshopOrdering:!0,dateEndFirstStepPublish:"November 29th 2018",dateEndSecondStepPublish:"December 20th 2018",dateEndThirdStepPublish:"February 18th 2019",dateEndFourthStepPublish:"May 9th 2019",dateEndFifthStepPublish:"July 8th 2019",remainingDaysToSecondStep:"2 months",secondStepPassed:!0,currentStepOfPublishingProcess:4,editedByType:null,editors:[{id:"176840",title:"Dr.",name:"Magdalena",middleName:null,surname:"Bełdowska",slug:"magdalena-beldowska",fullName:"Magdalena Bełdowska",profilePictureURL:"https://mts.intechopen.com/storage/users/176840/images/system/176840.jpeg",biography:"Associated professor dr hab Magdalena Bełdowska conducted her Ph.D and habilitation in Faculty of Oceanography and Geography University of Gdańsk, Poland. During her professional career, she has carried out research on toxic metals cycling in marine environment (especially in Baltic Sea). The research includes transboundary transport in the atmosphere, input of contaminations to the sea, bioaccumulation and biomagnification int marine trophic chain, deposition/ remobilization to/from the sediments. During that period she was leading several projects funded by National Science Centre (NCN, Poland). She has been involved in teaching students in the field of Chemical hazards in the aquatic environment; Metals cycling as a function of climate change; Environmental protection. She has published over 50 papers in indexed journals and international conferences",institutionString:"Institute of Oceanography of the University of Gdańsk",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"1",totalChapterViews:"0",totalEditedBooks:"0",institution:null}],coeditorOne:{id:"276044",title:"Dr.",name:"Jacek",middleName:null,surname:"Bełdowski",slug:"jacek-beldowski",fullName:"Jacek Bełdowski",profilePictureURL:"https://mts.intechopen.com/storage/users/276044/images/system/276044.jpeg",biography:"Assistant Professor, Dr hab. Jacek Bełdowski completed his PhD at the University of Gdańsk and Habilitation at Institute of Oceanology, PAS. His studies concentrated at mercury cycle in marine systems, Carbon cycle influence on Climate change (during 2 year postdoc at Institute for Baltic Sea Research, Warnemuende, Germany) and dumped chemical munitions. He has participated in three national and six EU projects devoted to contaminant cycles in the Baltic Sea and led two EU (CHEMSEA, DAIMON) and one NATO SPS (MODUM) projects, dealing with risk assessment of chemical and conventional munitions dumped at sea. He also served as co-chairman of HELCOM special working groups MUNI and SUBMERGED. During his career he has published over 40 peer revieved papers and book chapters, and led 25 Scientific cruises.",institutionString:"Institute of Oceanology",position:null,outsideEditionCount:0,totalCites:0,totalAuthoredChapters:"0",totalChapterViews:"0",totalEditedBooks:"0",institution:null},coeditorTwo:null,coeditorThree:null,coeditorFour:null,coeditorFive:null,topics:[{id:"10",title:"Earth and Planetary Sciences",slug:"earth-and-planetary-sciences"}],chapters:null,productType:{id:"1",title:"Edited Volume",chapterContentType:"chapter",authoredCaption:"Edited by"},personalPublishingAssistant:{id:"280415",firstName:"Josip",lastName:"Knapic",middleName:null,title:"Mr.",imageUrl:"https://mts.intechopen.com/storage/users/280415/images/8050_n.jpg",email:"josip@intechopen.com",biography:"As an Author Service Manager my responsibilities include monitoring and facilitating all publishing activities for authors and editors. From chapter submission and review, to approval and revision, copy-editing and design, until final publication, I work closely with authors and editors to ensure a simple and easy publishing process. I maintain constant and effective communication with authors, editors and reviewers, which allows for a level of personal support that enables contributors to fully commit and concentrate on the chapters they are writing, editing, or reviewing. I assist authors in the preparation of their full chapter submissions and track important deadlines and ensure they are met. I help to coordinate internal processes such as linguistic review, and monitor the technical aspects of the process. As an ASM I am also involved in the acquisition of editors. Whether that be identifying an exceptional author and proposing an editorship collaboration, or contacting researchers who would like the opportunity to work with IntechOpen, I establish and help manage author and editor acquisition and contact."}},relatedBooks:[{type:"book",id:"5962",title:"Estuary",subtitle:null,isOpenForSubmission:!1,hash:"43058846a64b270e9167d478e966161a",slug:"estuary",bookSignature:"William Froneman",coverURL:"https://cdn.intechopen.com/books/images_new/5962.jpg",editedByType:"Edited by",editors:[{id:"109336",title:"Prof.",name:"William",surname:"Froneman",slug:"william-froneman",fullName:"William Froneman"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7634",title:"Speleology",subtitle:null,isOpenForSubmission:!0,hash:"cee35d20a1625ecb4b6eeedeb35d0af0",slug:null,bookSignature:"Dr. Mualla Cengiz Çinku and Dr. Savas Karabulut",coverURL:"https://cdn.intechopen.com/books/images_new/7634.jpg",editedByType:null,editors:[{id:"199925",title:"Dr.",name:"Mualla",surname:"Çinku",slug:"mualla-cinku",fullName:"Mualla Çinku"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7746",title:"Lagoon Environments Around the World - A Scientific Perspective",subtitle:null,isOpenForSubmission:!0,hash:"372053f50e624aa8f1e2269abb0a246d",slug:null,bookSignature:"Prof. Andrew J Manning",coverURL:"https://cdn.intechopen.com/books/images_new/7746.jpg",editedByType:null,editors:[{id:"23008",title:"Prof.",name:"Andrew",surname:"Manning",slug:"andrew-manning",fullName:"Andrew Manning"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"8444",title:"Lunar Science",subtitle:null,isOpenForSubmission:!1,hash:"f1dcf511a174e8ec89d97ca8c0c6146a",slug:null,bookSignature:"Dr. Yann Chemin",coverURL:"https://cdn.intechopen.com/books/images_new/8444.jpg",editedByType:null,editors:[{id:"270578",title:"Dr.",name:"Yann",surname:"Chemin",slug:"yann-chemin",fullName:"Yann Chemin"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"8476",title:"Earth Crust",subtitle:null,isOpenForSubmission:!1,hash:"ebef9911d87b6db8cb55dad47250a6be",slug:null,bookSignature:"Dr. Muhammad Nawaz, Dr. Sandeep Narayan Kundu and Dr. Farha Sattar",coverURL:"https://cdn.intechopen.com/books/images_new/8476.jpg",editedByType:null,editors:[{id:"269790",title:"Dr.",name:"Muhammad",surname:"Nawaz",slug:"muhammad-nawaz",fullName:"Muhammad Nawaz"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"8791",title:"Karst Environment",subtitle:null,isOpenForSubmission:!1,hash:"1d91b463da08758cfc65420483c595a0",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/8791.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"9248",title:"The Milky Way System",subtitle:null,isOpenForSubmission:!0,hash:"364566b36a78a23c895936974dc002ee",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/9248.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7298",title:"Ore Deposits",subtitle:null,isOpenForSubmission:!1,hash:"d2dcde8e71f5cfd1b8efc177570835e7",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/7298.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7651",title:"Galaxies",subtitle:null,isOpenForSubmission:!1,hash:"fea1bc0b02d5e698ef6cd11da1850e82",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/7651.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7747",title:"Isotopes Applications in Earth Sciences",subtitle:null,isOpenForSubmission:!0,hash:"987cac30385e7770dd22b9d1ef0da4f7",slug:null,bookSignature:"",coverURL:"https://cdn.intechopen.com/books/images_new/7747.jpg",editedByType:null,editors:null,productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},chapter:{item:{type:"chapter",id:"62242",title:"Oxygen Reduction Reaction",doi:"10.5772/intechopen.79098",slug:"oxygen-reduction-reaction",body:'\nOxygen reduction reaction (ORR) has been the subject of extensive investigation over the last century [1]. This is largely because ORR is of major importance to energy conversion, in particular in the field of fuel cells and metal-air batteries [1, 2, 3]. ORR is the most important cathodic process in polymer electrolyte membrane fuel cells (PEMFCs) [4]. Among all catalysts evaluated, Pt is still the best catalyst for ORR. The major obstacle with Pt is that it belongs to the platinum group of metals, which are rare metals, hence too expensive for feasible commercialisation of fuel cells. This has led to more research being conducted in an effort to find alternate electrocatalysts that can be used.
\nOxygen reduction in aqueous solutions occurs mainly through two different pathways: either a four-electron reduction pathway from O2 to H2O or a two-electron pathway from O2 to H2O2. The most accepted mechanism of ORR was first proposed by Damjanovic et al. [5, 6] and later modified by Wroblowa et al. [7], making it easier to understand the complicated reaction pathway of oxygen on the metal surface. They suggest that ORR proceeds along two parallel reaction pathways with rates that are comparable. In PEMFCs, a four-electron transfer is preferred.
\nThe ORR is alkaline media versus reversible hydrogen electrode (RHE) at 25°, and its thermodynamic potentials at standard conditions are presented as follows [3, 8, 9]:
\nThe pathway involving the hydrogen peroxide is expressed as follows [10]:
\nThe ORR is acidic media versus RHE at 25°, and its thermodynamic potentials at standard conditions are presented as follows:
\nDirect four-electron reduction:
\nIndirect reduction:
\nOr chemical decomposition:
\nIt is desirable for the ORR to occur at potentials close to thermodynamic potentials as much as possible. For the thermodynamic potentials to be obtained, the charge transfer kinetics of the ORR must be quick. It has been reported that the kinetics of fuel cells at cathode are slow, hence show over-potential ƞ as in Eq. (7) [3, 11]:
\nE is the resultant potential and Eeq is the equilibrium potential.
\nThe difference between E and Eeq is called polarisation.
\nThere are three distinct types of polarisation expressed in Eq. (8):
\nƞact is the activation over-potential, a function describing the charge transfer kinetics of an electrochemical reaction. ƞact is always present and mostly dominant at small polarisation currents.
\nƞconc is the concentration over-potential, a function describing the mass transport limitations associated with electrochemical processes. ƞconc is predominant at larger polarisation currents.
\niR is the ohmic drop. This function takes into account the electrolytic resistivity of an environment when the anodic and cathodic elements of a corrosion reaction are separated by this environment while still electrically coupled.
\nThe graph in Figure 1 depicts a polarisation curve showing the electrochemical efficiency of a fuel cell.
\nThe polarisation curve shows the electrochemical efficiency of the PEMFC at any operating current [12].
The expression relating the over-potential, ƞ, and the net current is known as the Butler-Volmer equation and is given as follows [13]:
\nwhere i is the ORR current density, io is the exchange current density, n is the number of electrons transferred in the rate-determining step, β is the transfer coefficient, β is the over-potential of ORR, F is the Faraday constant, R is the gas constant and T is the temperature in K. The first term in the Butler-Volmer equation represents the anodic reaction/metal dissolution, while the second term represents the cathodic reaction/metal deposition. A plot of the Butler-Volmer equation gives the polarisation curve as shown in Figure 2.
\nCurrent-potential relationship of a metal dissolution (M → Mn+)/deposition (Mn+ → M) process [13].
There are two limitations in the Butler-Volmer equation.
A low over-potential region, also known as polarisation resistance/charge transfer resistance, where the Butler-Volmer equation simplifies to [13]
At high over-potentials region, the Butler-Volmer equation simplifies to Tafel equation
A plot of ƞ versus log ic also known as the Tafel plot and gives a linear relationship, with slope \n
The kinetics of the ORR at the cathode are very important, as they are the factors for the performance of PEMFCs [14, 15]. There are several issues that need to be addressed, including slow reaction kinetics at the cathode, which are due to highly irreversible ORR, and fuel crossover in the cathode, which causes a mixed potential, leading to potential loss and 25% reduction in efficiency, hence reducing the ORR performance [16, 17, 18, 19]. An electrocatalyst is used to induce a four-electron reduction of O2 to water by utilising the protons that permeate from the anode. Pt is the electrocatalyst that is currently used for ORR reactions, as it is the only commercially available catalyst with sensible activity and stability for PEMFCs, although it offers limited commercialisation of fuel cells due to its limited availability and high cost [4, 20]. It is also reported that Pt still shows over-potentials of over 400 mV from the equilibrium reversible potentials (1.19 V at 80°C) [21]. These high potentials result in the formation of adsorbed species on a platinum surface that restrain the ORR and hence result in performance loss [2]. Considerable research has been conducted to try to (1) reduce the costs of fuel cells, which is one of the stumbling blocks in fuel cell commercialisation using low-cost non-Pt catalysts such as supported platinum group metals Pd, Ir and Ru; (2) improve the electrocatalytic activity of the cathode catalyst, which includes using bimetallic alloy catalysts, transition metal macrocyanides, transition metal chalcogenides and metal oxides in order to improve the ORR kinetics on the new catalyst; and (3) fabricate Pt with novel nanostructures such as nanotubes, graphene and carbon nanofibres (CNFs), as it is known that supports may significantly affect the performance of the catalyst. However, these efforts are still in the research stage, as their activity and stability are still lower than that of the Pt catalyst.
\nOther noble metals, such as Pd, Ag, Rh, Ir and Ru, have also been used as cathode materials for ORR [22]. Among these, Pd, which has the same electron configuration and lattice constant as Pt, as they belong to the same row in the periodic table, showed the most improved ORR towards alcohol in an alkaline medium, while it is reported to be inactive in an acid medium [4, 23]. It has been showed that Pd/C is less sensitive to alcohol contamination compared to Pt/C, hence more tolerant to alcohol crossover [16, 24, 25]. However, when comparing the ORR activity of Pd/C to Pt/C, the former has less activity and high potentials of amount 0.8 V versus NHE, hence less stability, which prevents its replacement as the preferred ORR catalyst over Pt/C [26]. The noble metals in terms of ORR activity follow the trend: Pt > Pd > Ir > Rh [27]. Wang [18] reports that Ru can undergo a four-electron reduction reaction. Ag is reported to show less electrocatalytic activity towards ORR compared to Pt, but is more stable than Pt cathodes during long-term operations [4].
\nThere are several metals other than noble metals that were also evaluated as cathode catalysts for ORR. Figure 3 shows a comparison of the activities of various catalysts as a function of binding energy. These catalysts showed less catalytic activity towards ORR compared to Pt, with less electrochemical stability [28].
\nOxygen reduction activities as a function of oxygen-binding energy [27].
Transition metals such as Fe, Ni, Co and Cr have been extensively studied due to their improved ORR electrocatalytic activity as alloys for Pt in the presence of a support [17, 28]. Yuan et al. [17] prepared PtFe/C using the impregnation method. Current densities of PtFe/C for ORR in methanol were higher (78.6 mA cm−2) than in Pt/C (65.0 mA cm−2), but was lower in methanol-free solutions, indicating that PtFe/C is a better methanol-tolerant catalyst compared to Pt/C. In terms of power density, the PtFe/C showed an improvement of 20–30% compared to Pt/C [17]. Other researchers [29, 30] also reported better performance of PtFe/C for ORR. Yang et al. [31] report on PtNi/C prepared via the carbonyl complex route an improved mass and specific activity of PtNi/C compared to Pt/C with an improved electrocatalytic activity towards ORR. Pt-Bi/C showed improved methanol tolerance for ORR compared to Pt/C [3]. Remona and Phani [32] synthesised PtBi/C by micro-emulsion. The PtBi/C displayed a higher methanol tolerance compared to mass activity (1.5 times higher) for ORR compared to Pt/C. The high ORR activity of PtBi/C was due to distortion (internal stress) of three Pt sites by Bi.
\nThe effect of Pd on Pt catalysts has been reported by various researchers [33, 34, 35, 36], who all reported an improved electrocatalytic activity towards ORR. The improved electrocatalytic activity of Pt alloys has been ascribed to geometric effect, namely a decreased Pt-Pt bond distance, the dissolution of more oxidisable alloying components, a change in surface structure and electronic effect, that is, an increase in Pt d-band vacancy [31, 37]. Other noble metals (Au, Ir, Rh and Ru) were also studied as Pt alloys. PtAu/CNT (carbon nanotubes) was reported to show an improved electrocatalytic activity in an alkaline membrane compared to Pt/CNT [38, 39, 40]. Pd-Pt alloy had the highest electrocatalytic activity towards ORR compared to other Pt-alloyed noble metals. Fu et al. [41] report on an improved ORR electrocatalytic activity and a larger diffusion-limiting current density compared to commercial Pd black. The improvement of Pt with noble metals (Pd, Ag and Au) is attributed to these metals having a fully occupied d-orbital. The d-orbital coupling effect between metals decreases the Gibbs free energy for the electron-free steps in ORR, resulting in improved ORR kinetics [37].
\nBinary Pd catalysts (Cu, Ni, Fe, Co, W and Mo) have been identified as promising cathode catalysts for ORR with an improved electrocatalytic activity and stability compared to Pd alone due to changes in Pd-Pd bond length, modification of the electron configuration and change of surface species and compositions [4, 25]. Kim et al. [42] used PdSn/C as a cathode for direct methanol fuel cells. Their results exhibited a high performance in high methanol concentrations compared to commercial Pt/C. Wang [18] reports on PdCo catalysts tested for ORR. The results showed improved activities towards ORR, with PdCo improvement only observed when less than 20% Co was used. Meng et al. [4] report on PdFe, PdCu, PdAg and PdCo, which all showed an improved electrocatalytic activity compared to Pd alone. In the presence of alcohol, the binary Pd catalysts showed an improved electrocatalytic performance for ORR compared to Pt.
\nAlthough bimetallic catalysts (Pt with Fe, Ni, Co, etc.) have shown improvement in the performance of the ORR compared to Pt [27], the lack of preparation methods to control large synthesis has limited its use in commercial devices [33]. In addition, the dissolution of transition metals alloyed in the Pt-M catalyst is a major drawback, because these transition metals are electrochemically soluble at a potential range between 0.3 and 1.0 V versus NHE in acidic media [43].
\nOne possible way to overcome the dissolution of transition metals and improve stability of catalysts is by preparing multi-component catalysts (three and more electrocatalyst alloys). The multi-component catalysts are able to shift the d-band centre by a strain effect (caused by the lattice mismatch in the multi-component system) and lower the adsorption energy of surface oxygenated intermediates, thereby enhancing the surface catalytic activity.
\nTiwari et al. [37] report on various multi-component catalysts that have been synthesised over the years with either Pt or Pd, including PtTiM (M = Co, Cr, Cu, Fe, Mn, Mo, Ni, Pd, Ta, V, W and Za), PtCuCo, PtCoSe2, PtIrCo, PdFePt, PtCuCoNi, PdSnPt and PdCoPt. From the multi-component catalysts, they reported an improved electrocatalytic activity towards ORR compared to pure Pt and the possibility of reducing the costs of the electrocatalysts for PEMFCs.
\nMore research is also done on trying to improve the kinetics of Pt catalysts through the development of new and the optimisation of existing synthesis methods that can control the shape and surface structure of the electrocatalyst in order to improve its performance [8, 33, 44, 45]. There has been contracting reports on particle size and specific activity. Some researchers report a decrease in specific activity with a decrease in particle size, while other researchers report an increase in specific activity with a decrease in particle size. The discrepancy may be the result of different electrocatalysts with different shapes and degree of agglomeration [46]. It has been reported that metallic nanostructures with different shapes display unique chemical and physical properties [47]. Significant progress has been made for size-controlled spherical nanostructures, but only limited progress has been made with non-spherical nanostructures, which are reported to show more improved ORR electrocatalytic activity for fuel cells compared to spherical-shaped electrocatalysts, the reason being that the highly symmetric face-centred cubic crystal structure of Pt-based catalysts makes it not easy to obtain a non-spherical shape, which involves a competition over the desire to minimise the surface energy through the formation of thermodynamically stable spherical shapes. Hao et al. [48] report that cubic Pd nanocrystals exhibit better performance in methanol compared to the spherical Pd catalyst of a similar size. The improvement was attributed to cubic nanocrystals that contain a more electroactive surface area compared to its spherical counterpart. It has also been reported that Pt electrocatalysts with a tetrahedral shape showed much improved reaction kinetics compared to the spherical Pt nanoparticles. It has been reported that low-index crystal planes give poor electrocatalytic properties, while high-index planes give a high electrocatalytic activity and stability [47, 49]. Pt nanocubes have been reported to have much improved specific activity for ORR compared to commercial Pt catalysts (spherical) [47, 50]. Kuai et al. [50] report on uniform, high-yield icosahedral Ag and Au nanoparticles prepared using a hydrothermal system in the presence of polyvinylpyrrolidone and ammonia. The prepared Au and Ag nanoparticles showed an improved ORR electrocatalytic activity and excellent stability compared to spherical Pt/C nanoparticles.
\nThe form or shape of the electrocatalysts depends on the synthesis method and the various parameters used. Figure 4 shows the formation of various forms of Pt nanocubes using different strategies based on the polyol method [47]. The formation of Pt tubes can be obtained through two different routes, either galvanic displacement or using selected templates [47]. Researchers have synthesised metal nanoparticles with various shapes [32].
\nDifferent routes for the synthesis of Pt nanocubes along with their electron micrographs [47].
Researchers are reporting an improved electrocatalytic activity of ORR using various synthesis methods focusing on surface structure. Lim et al. [14] report on the synthesis of Pt/C using the modified polyol method using ethylene glycol as the reducing agent. The prepared catalyst had the highest mass activity, which was 1.7 times higher than the commercial Pt/C [14]. The improvement was attributed to small and uniform particle size and better dispersion. Adonisi et al. [51] report on various Pt-based catalysts synthesised using the Bonnemann method. Some of those catalysts showed an improved ORR electrocatalytic activity compared to commercial Pt/C. Figure 5 shows a graph depicting 20% Pt/C commercial compared to 20% Pt/C synthesised catalysts using the Bonnemann method. From the graph, it can be observed that the 20% Pt/C commercial catalyst was found at lower current densities than the prepared 20% Pt/C catalyst. The mass activities of the 20% Pt/C commercial and 20% Pt/C prepared catalysts were found to be 12.6 and 15.8 A/g, respectively, and the specific activities were found to be 0.060 and 0.063 A cm−2, respectively. This improvement was attributed to the particle size of the prepared catalysts, which was smaller than the particle size for the commercial Pt/C catalyst.
\nCyclic voltammograms for ORR of 20% Pt/C commercial and prepared electrocatalysts in O2-saturated 0.5 M H2SO4 at a scan rate of 20 mV [51].
Post-treatment after synthesis has been reported to change the physicochemical properties of the electrocatalysts. Heat treatment is considered as one of the important and sometimes necessary steps to improve the activity of the catalysts [52]. Heat treatment involves heating the catalyst under inert (N2, Ar or He) or reducing H2 atmosphere in the temperature range of 80–900°C for 1–4 h [52]. The benefit of heat treatment is the removal of impurities resulting from the preparation stages, allowing uniform dispersion and stable distribution of the catalyst on the support, thereby improving the electrocatalytic activity of the prepared catalyst. It has been determined that the electrocatalytic reduction of oxygen on the catalyst can be influenced by the particle size and surface structure, and hence treatment can have an effect on ORR activity and stability by altering the surface structure of the catalyst [32]. Various researchers have worked on heat treatment of mono and bimetallic catalysts for ORR [50]. They all concluded that heat treatment improves alloying of the catalysts, which decreases the Pt-Pt distance and hence d-band vacancy of the Pt and thus improves the electroactivity of the catalyst [53]. Jeyabharathi et al. [54] report on improved methanol tolerance of PtSn/C after heat treatment, while the ORR activity remained intact. Sarkar et al. report on PdW synthesised using thermal composition followed by annealing at 800°C with an improved electrocatalytic activity for ORR and catalyst durability with an improved methanol tolerance compared to Pt [32].
\nTransition metals such as macrocycles and chalgogenides have been used as ORR catalysts since the 1960s due to their inactivity towards the oxidation of methanol [55]. Other than noble metals, they are the most-studied electrocatalysts for oxygen reduction. The study of ruthenium chalgogenides RuxSey and Pt for ORR has shown that the performance of RuxSey is slightly weaker than Pt and that the difference was their behaviour in the presence or absence of methanol. Under these conditions, the electroactivity of RuxSey is not changed, while for Pt, the potential shifts to the negative direction (120–150 mV). A similar behaviour was observed when RuxSey was embedded in a polymetric matrix, such as polyaniline. RuSM (M = Rh, Re, Mo, etc.) when used as catalysts, methanol oxidation on the cathode was suppressed or avoided leading to a reduced mixed potential. The results confirm that the chalgogenide of Ru is insensitive to methanol, in contrast to the Pt catalyst [56]. The main concern with this approach was the low power output due to low activity of these catalysts for ORR, compared to the Pt catalyst [17]. Cobalt and iron phthalocyanide are the most-studied transition metals as centres for macrocycling rings as catalysts for ORR in fuel cells [56, 57]. These ORR catalysts have shown that a number of metal chelates will chemisorb oxygen [58]. A fuel cell with an iron phthalocyanide cathode can only be stable for up to 10 h [17], but has shown improved activity towards ORR in alkaline media [44]. Zagal et al. [59] report that when Fe chelates with N4, a four-electron ORR occurs. Co phthalocyanide has demonstrated similar ORR kinetics as commercial Pt/C, as it also leads to a four-electron process per oxygen molecule, that is, to water, but at lower potentials (0.25 and −0.25 versus RHE) [44, 56]. However, these compounds are not completely stable under strong acid conditions [17, 56]. They decompose via hydrolysis in the electrolyte and attack the macrocyanide via peroxide, causing poor performance and stability [58, 60, 61]. Transition metal chalgogenides are more stable and show an improved electrocatalytic activity at temperatures above 800°C.
\nAnother route to stabilising nanoparticles is the development of metal oxide composite supports. Metal oxides such as IrO2, NiO, CeO2, ZrO2, TiO2 and SnO2 have also been studied as ORR catalysts in basic acidic media [62, 63, 64, 65, 66]. Nanoparticles on metal oxides are not able to improve the electrocatalytic activity due to their limited electron conductivity, but are reported to have excellent corrosion resistance in various electrolyte media [66, 67]. Researchers use metal oxides in combination with carbon supports that have desirable properties such as a high surface area and a high electric conductivity. The metal oxides combined with carbon supports are reported to improve the stability and the electrocatalytic activity of the electrode material. Carbon surfaces are functionalised before they are used as supports for catalysts in order to improve their surface properties, but the disadvantage of functionalisation is that it accelerates the degradation process of the support material. The presence of the metal oxide delays the corrosion process. Montero-Ocampo et al. [68] report on PtTiO2 and PtTiO2/CNT synthesised using metal organic chemical vapour deposition. The PtTiO2/CNT was more electrocatalytically active compared to PtTiO2, while good stability was observed for both PtTiO2 and PtTiO2/CNT that was provided by the TiO2 support. This was attributed to the high conductivity of CNT compared to TiO2, which has limited electron conductivity. Pt/TiO2/C showed improvement in activity and thermal stability for ORR compared to Pt/C [69]. Khotseng et al. [70] compared the activity for PtRu/TiO2 to commercial PtRu/C and Pt/C. They reported a high electroactive surface area and activity of commercial Pt/C and PtRu/C compared to PtRu/TiO2 towards ORR. When durability studies were performed for the same catalysts, the PtRu/TiO2 recorded a loss of 29% compared to Pt/C and PtRu/C, which recorded a loss of 64 and 32%, respectively. Li et al. [71] reported an improved oxygen reduction activity, a better durability and a higher methanol tolerance capability in alkaline solution compared to Pt/C.
\nMost metal oxides were found to be unstable in acidic media. To overcome this instability, conducting polymer polypyrrole (Ppy) was used against the dissolution of metal oxides. During synthesis, the metal oxides were sandwiched between the Ppy layers. Through this research, an improved electrochemical stability of the metal oxides was achieved [18]. Singh et al. [72] report on CoFe2O4 oxides sandwiched between Ppy layers. A high electrocatalytic activity towards ORR at high cathodic potentials was obtained with stability in acidic media [72].
\nAlthough Pt-based catalysts have been widely studied due to their high current density and low over-potential, when used as cathode catalysts, their activity is lowered due to slow reaction kinetics. More research is required to try to improve the catalyst activity. One of the focus areas is looking into loading Pt nanostructures with a high activity on the surface of supporting materials with (1) low cost, (2) good electrical conductivity, (3) strong catalyst-support interaction that is influenced by its surface functionalities to limit the possible deactivation of the electrocatalyst and allow for efficient charge transport, (4) large surface area and (5) good resistance to corrosion to allow high stability [8, 22, 24, 73, 74, 75]. Carbon black (CB) is the most-used support for Pt and Pt alloy catalysts. CB is thermochemically unstable and hence suffers from corrosion, leading to performance degradation and durability issues and high potential [66, 76]. Nanostructured carbon materials, for example, mesoporous carbon, CNFs, CNTs and graphene, have been studied extensively as support materials for electrocatalysts, as they have been identified as some of the most promising materials for PEMFCs due to their high chemical stabilities, high electric conductivities and improved mass transport capabilities [32, 77].
\nCNTs are attractive support materials in fuel cell applications and are by far the most-explored carbon nanostructures as catalyst supports in fuel cells due to their excellent mechanical strength, a high surface area and a high electric conductivity and because they have reported to show an improved catalytic activity [22, 32, 78] compared to CB. The carbon surface is functionalised to provide oxygen-binding groups for the growth of metal catalyst ions [79]. CNTs can be single-walled (SWCNT) or multi-walled (MWCNT), depending on the structure. Both SWCNT and MWCNT have been used as support materials to disperse the electrocatalyst and have been reported to show an enhanced electrocatalytic activity towards ORR. SWCNTs have unique electrical and electronic properties, a wide electrochemical stability and high surface areas [9]. When compared to commercial Pt/C (from ETEK) in acidic media, the SWCNT showed an improved electrocatalytic activity performance, with the negative shift of onset potential by 10 mV compared to Pt/C, whose onset potential moved to a higher potential by 15 mV [15, 73]. Jukk et al. [80] report on Pd/MWCNT having an enhanced electrocatalytic activity compared to Pd/C for ORR. Wang et al. [81] reported on Pt/MWCNT, which showed an improved electrocatalytic activity for ORR compared to Pt/C. Khotseng et al. [70] compared PtRu/MWCNT with commercial Pt/C, PtRu/C and prepared PtRu/TiO2 and PtRu/MoO2. From Figure 6 and Table 1, it is observed that PtRu/MWCNT has the highest mass and specific activity at 0.9 V compared to commercial Pt/C, PtRu/C and prepared PtRu/TiO2 PtRu/MoO2 with the highest current density towards ORR.
\nORR polarisation curves of PtRu/MWCNT PtRu/MWCNT compared to Pt/C, PtRu/C PtRu/TiO2 and PtRu/MoO2 commercial catalysts in O2-saturated 0.1 M HClO4 at 20 m V/s and 1600 rpm [70].
\n | ORR catalytic activity at 0.9 V | \n|
---|---|---|
Catalyst | \nMA (mA mg−1) | \nSA (mA cm−2) | \n
Pt/C | \n85.85 | \n0.188 | \n
PtRu/C | \n463 | \n1.66 | \n
PtRu/MWCNT | \n35.6 \n | \n111 | \n
PtRu/TiO2 | \n18.94 | \n1.04 | \n
PtRu/MoO2 | \n997 | \n17.82 | \n
Studying the activity of electrocatalysts towards ORR in comparison with commercial Pt/C, PtRu/C and PtRu/TiO2.
The two main functionalities are oxygen, namely carboxyl (▬COOH), hydroxyl (▬OH) and carbonyl (▬C=O), and nitrogen groups. Modified CNTs with nitrogen functional groups have been reported to show a much improved electrocatalytic activity towards ORR through forming thermally stable structures during heat treatment [82, 83]. Nitrogen is known to efficiently create defects on carbon materials, which might increase the edge plane exposure and thus improve the ORR activity [29]. Ghosh and Raj [84] report on an improved electrocatalytic activity towards ORR for N-doped CNTs. Wang et al. [85] report on a sponge-like nitrogen containing carbon with a high electrocatalytic ORR activity compared to commercial Pt/C with a considerably higher methanol tolerance. One distinct advantage offered by CNTs is their high resistance towards corrosion compared to CB, and hence they have an enhanced electrochemical stability compared to CB [66, 84].
\nCNFs have been reported to show an improved electrocatalytic activity towards ORR compared to CB [66]. Yang et al. [86] report on an improved electrocatalytic activity for ORR for Pd/CNF. The biggest difference between CNTs and CNFs is their exposure of active edge planes. For CNTs, the basal planes are exposed, while for CNFs, edge planes are exposed [66].
\nGraphene and graphene oxide (GRO) have also been investigated as another support material for electrocatalysts in fuel cells due to their high electron transfer rate, a large surface area and a high conductivity [64]. When compared to CNTs, they have a higher surface area and a similar electric conductivity for electrochemical applications and can also be produced at a lower cost compared to CNTs [21]. In graphene, both basal and edge planes interact with the electrocatalysts, while for CNTs, only basal planes are exposed [66]. A surface built up only of basal planes is said to have a homogeneous surface, while a surface built up of both basal and edge planes is said to have a heterogeneous surface. Heterogeneous surfaces are reported to better stabilise the metal in a highly dispersed state. It has been reported that Pd/GRO shows a better ORR activity and forms a four-electron oxygen-reduction process compared to Pt [87, 88, 89]. N-doped graphene has been reported to show an improved electrocatalytic activity towards ORR compared to graphene in acidic and alkaline media [90]. Lu et al. [91] report a superior electrocatalytic activity of N-GRO compared to GRO. The fast electron transfer rate of graphene can particularly facilitate ORR much quicker in fuel cells [66].
\nOther nanostructured carbon supports such as mesoporous carbon, carbon nanocoils and carbon aerogel have also been used as support material for cathode catalysts and have been reported to show an improved ORR electrocatalytic activity [76].
\nAlthough carbon supports have been reported to show an improved ORR electrocatalytic activity, carbon oxidation or corrosion due to the presence of O2 and/or high electrode potential has been identified as one of the major causes of failure for PEMFC degradation [67]. Non-carbon supports such as electrically conducting polymers, for example, polyaniline, Ppy and mesoporous silica, have also been used as supports to improve the stability of the electrode materials. Shurma and Pollet [66] and Wang et al. [67] report on various non-carbon supports for electrocatalysts for fuel cells. However, it is reported that with non-carbon supports, no major breakthrough has been achieved as yet [66].
\nORR is also studied in alkaline media using anion exchange membranes (AEMs) [92]. The significant reason for the change in electrolyte membrane from acid to alkaline is the improved electrokinetics of ORR in alkaline [93]. Pd is emerging as an alternative catalyst compared to Pt in alkaline. It is reported that more ORR catalysts are available for alkaline solutions compared to acidic solutions, due to excessive corrosion in acidic media. Pt/C in basic media is said to enhance ORR towards alcohol [94, 95], while non-Pt catalysts also showed an improved ORR when employed. In addition, in alkaline media, Pt/C is more tolerant to alcohol crossover due to its inactivity in alcohol oxidation reaction. Pd alloys are reported to be comparable or slightly better than Pt/C [4]. Kim et al. reported on PdSn using anion exchange membrane (AEM) which showed an improved ORR electrocatalytic activity with a high methanol tolerance compared to commercial Pt/C tested in proton exchange membrane [42]. He and Cairns [96] report on various electrocatalysts for ORR in AEM.
\nOxygen reduction on Pt is one of the most extensively studied mechanisms [3]. It involves a multi-electron process with a number of elementary steps, involving different reaction intermediates. The mechanism can be shown schematically as follows [97] (Figure 7).
\nA simplified schematic pathway of oxygen reduction reaction for both acidic and alkaline media [7].
From the mechanism, only two products are observed with ORR on Pt, either H2O, which can directly form through a four-electron reduction with the rate constant k1, or adsorbed hydrogen peroxide (H2O2, ads), which is through a two-electron process with the rate constant k2, which can be reduced further by another two-electron process to form water with rate constant k3, or be chemically decomposed on the electrode surface (k4), or be desorbed in the electrolyte solution (k5). For ORR in fuel cells, the direct four-electron process is required.
\nOxygen reduction on a Pt catalyst in acid media occurs via dissociative adsorption of O2 followed by the protonation of the adsorbed species, with the former being the rate-determining step [55].
\nThe main steps in the mechanism of ORR are given subsequently. One is known as dissociative mechanism for a low current density range and the other associative mechanism for a high current density range:
\nDissociative mechanism:
\nIn this mechanism, no H2O2 is formed. On the Pt surface, the O2 adsorption breaks the O▬O bond and forms adsorbed atomic O with further gain of two electrons, in the two consecutive steps, forming H2O. Because there is no adsorption of O2 on the surface, no H2O2 can be formed. This mechanism can be considered as the direct four-electron reduction reaction.
\nAssociative mechanism:
\nIn this mechanism, no H2O2 is involved as well. Because there is adsorbed O2 on the surface, O▬O may not be broken down in the following steps, resulting in the formation of H2O2, which can be reduced further to form water.
\nPt shows two Tafel slope regions. At a high potential, low current density (>0.8 V), the electrode surface is a mixture of Pt and PtO with the Tafel slope of 60 mV dec−1 and the reaction order 0.5 with respect to pH in alkaline media. The fractional reaction order was represented in terms of the first electrochemical step as a rate-determining step under the Temkin isotherm, that is, the adsorption of reaction intermediates Oads, OHads and HO2ads [98, 99].
\nThe rate expression under Temkin conditions of adsorption is
\nwhere k is the rate constant and ƞ is the over-potential.
\nAt a low potential, high current density (<0.8 V), the electrode surface is a pure Pt with the Tafel slope of 120 mV dec−1 and the reaction order 0 with respect to pH in alkaline media, with H2O as the reacting species. The adsorption of intermediate species to a Langmuir isotherm under Temkin conditions no longer holds.
\nThe rate expression under Langmuir conditions is
\nwhere β is the symmetry factor.
\nThe reaction is of the first order with respect to O2 in solutions. It was found that the H2O2 formed was greater in an alkaline solution than in an acidic one [4, 94]. In alkaline solutions, about 80% of the reduction current is through the direct reduction and the other current forms H2O2, which leads to a complicated mechanism.
\nVarious models representing the adsorbed states of oxygen are represented in Figure 8.
\nOxygen reduction on Pt from the (a) bridge model, (b) Griffiths model and (c) Pauling model [100].
Figure 8(a) is known as the bridge model. It is a 2:2 complex of metal oxygen where the bonding arises from the interaction between the d-orbital on the metal with a Π* and Π orbital combination on O2 [101]. This gives rise to a singlet or a triplet nature of di-oxygen orbitals and determines the bridge or a transmode of interaction of di-oxygen with the metal [101]. Figure 8(b) is known as the Griffiths model. It is a 2:1 metal-di-oxygen complex structure, which involves a side on the interaction of oxygen with metal. This type of bonding can be viewed as rising from two contributions: (1) σ-type bonding is formed by overlapping between the Π orbitals of oxygen and the dz2 orbitals on the metal; (2) Π back-bond interaction between the metal d Π orbitals and partially occupied Π* antibonding orbital on O2 arises [102]. Figure 8(c) is known as the Pauling model. It is a 1:1 metal-oxygen complex structure, which is an end-on interaction of O2 with metal. In this model, the σ bond is formed by the donation of electron density from the σ-rich orbital of di-oxygen to the acceptor dz2 orbital on the metal. The metal’s two d-orbitals, namely dxz and dyz, then interact with the Π* orbitals of di-oxygen, with the corresponding charge transfer from the metal to the O2 molecule. The Griffiths and Pauling models are the preferred models due to the donating abilities of the filled Π and σ orbitals of the di-oxygen molecule, respectively [103].
\nORR has a huge role to play in fuel cell development. Comparing the ORR electrocatalytic activity of Pt with other single metals, Pt shows the most improved electrocatalytic activity, but its large-scale applications are limited by its high cost and scarcity. The addition of a second metal to a metal electrocatalyst decreases its particle size (large surface area), which leads to an increased lattice strain and hence an increased electrocatalytic activity [28]. It has been concluded that multi-component catalysts improve ORR activity, although it is not conclusive on which multi-catalyst shows the most improved ORR activity, as various researchers report on different multi-component catalysts as the most improved. Although improvement has been obtained, the Pt loading required is still too high to produce PEMFCs at commercially viable prices [22]. The transition metal phthalocyanine is offering reasonable performance as an ORR catalyst, although it suffers from lack of long-term stability.
\nThe challenge remaining is optimising the synthesis method in order to control the shape and the surface structure of especially non-spherical electrocatalysts, which are reported to show the most improved ORR electrocatalytic activity with most stable electrocatalysts, while they contribute to the lowering of Pt usage and hence cost reduction of the PEMFC.
\nCatalyst support is one of the critical components in improving the electrocatalytic activity of PEMFCs, as they are responsible for parameters that govern the performance of the fuel cell, that is, particle size, catalyst dispersion and stability [8]. Comparison of the carbon supports, CNTs and graphene supports provides considerable advantages concerning mass and charge transport. The disadvantage of using these supports is the costs [25]. In addition, the deposition, distribution and crystallite size of metal nanoparticles are affected by the synthesis method and oxidation treatment of carbon supports.
\nUsing an alkaline medium, Pt-free nanoparticles can be used as electrocatalysts for fuel cells, with a reduced alcohol crossover, an improved ORR kinetics and limited risks of corrosion. Recently, research has been focused on using AEMs. The main advantage of using AEM fuel cells over PEMFCs is that it allows for the use of less expensive, Pt-free electrocatalysts. AEM fuel cells promise to solve the cost barriers of PEMFCs.
\nI thank ESKOM (TESP), NRF (THUTHUKA), Ithemba Labs, Physics Department (UWC), Chemical Engineering Department (UCT) and Chemistry Department (UWC).
\nI have no conflict of interest to declare.
\n anion exchange membrane carbon black carbon nanofibre carbon nanotube graphene oxide multi-walled carbon nanotube normal hydrogen electrode oxygen reduction reaction polymer electrolyte membrane fuel cell polypyrrole reversible hydrogen electrode single-walled carbon nanotube
This chapter reviews the roles played by constraint-induced movement therapy (CIMT) in the rehabilitation of movement impairment following stroke. The chapter discusses these issue under three major sections and a conclusion section. The sections are overview on stroke, control of human movement, and the role of CIMT. The section on overview on stroke comprises of definition of stroke, etiology of stroke, pathophysiology of stroke, epidemiology of stroke, and consequences of stroke. The section on control of human movement consists only of nervous system control of movement in health and disease. The section on the role of CIMT consists of constraint-induced movement therapy: historical background and neuroscientific basis, components of CIMT, protocols of constraint-induced movement therapy, effects of constraint-induced movement therapy, and constraint-induced movement therapy: the future perspective. Information from all the sections to be discussed is needed by the physiotherapist in order to be able to make an effective clinical decision during application of CIMT in people with stroke.
World over, stroke has become a major public health issue. It is defined as “a rapidly developing clinical signs of focal (or global) disturbance of cerebral function, lasting more than 24 h or leading to death, with no apparent cause other than that of vascular origin” [1]. This definition seems outdated since presently there are advances in prevention, diagnosis, and management of stroke, which led to so many people surviving stroke and living with long-term disabilities. Additionally, stroke is a compendium of neurovascular syndromes with diverse presentations, and the 24 h time limit is not sacrosanct as minutes or few hours of stroke event can lead to severe and/or permanent damage [2]. Consequently, attempts were made to reassess the definition of transient ischemic attack and stroke [2, 3]. A high-powered committee of experts deliberated and defined the conditions; thus, stroke is classically characterized as a neurological deficit attributed to an acute focal injury of the central nervous system (CNS) by a vascular cause, including cerebral infarction, intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH), and is a major cause of disability and death worldwide [2]. This definition included the vascular causes of the condition. Thus, from the foregoing, it can be seen that stroke results from various vascular events and can manifest as varied forms of neurological signs and symptoms.
As stated in the definitions by Hatano and Sacco and his colleagues, the causes of stroke are of vascular origins [1, 2]. These sources are ischemia and intracerebral and subarachnoid hemorrhage, which may cause cerebral infarction. Ischemia simply means reduction in blood supply to brain cells, which could be due to occlusion as a result of the presence of either thrombus (a blood clot) or embolus (a moving blood clot) or stenosis (narrowing or reduction in the caliber of the arteries) [4]. The embolus usually may originate from the arteries or the heart as a result of conditions such as atrial fibrillation, sinoatrial disorder, recent acute myocardial infarction (AMI), marantic or subacute bacterial endocarditis, cardiac tumors, and valvular disorders, both native and artificial [5]. The intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH), which mean rupture or leakage of the tiny or very small blood vessels in the brain, are mainly caused by the elevated or increased intracranial pressure and sustained weakening of walls of blood vessels usually as a result of a long-standing high blood pressure [6]. Although majority of stroke cases are due to ischemia, in very rare cases, hemorrhagic and ischemic stroke can occur concurrently [7]. However, when stroke occurred as either ischemic or hemorrhagic, the latter usually leads to poor prognosis including mortality than ischemic stroke [8].
The human brain under normal circumstances receives 20% of the cardiac output [9]. This output is responsible for cerebral blood flow (CBF) whose normal value in adults is about 50–55 ml/100 g/min. This makes the brain tissues to be rich and abundant in oxygen and glucose necessary for major metabolic processes at all times. Thus, damage to the brain tissues due to reduced blood flow depends on the extent of the reduction to the tissues and probably for how long the reduction persists. If the CBF reduced to about 14 ± 2 ml/100 g/min, the damage is usually reversible, and the affected area is known as ischemic penumbra. The penumbra is a region of functionally impaired, but structurally intact, tissues. Thus, this area of penumbra is the one that offers hope for recovery in case of therapy and rehabilitation. On the other hand, if the CBF reduced to about 6 ml/100 g/min, the damage is usually irreversible, and the affected area is known as the core. The core is the region of infarction. This is because the human brain is not endowed with respiratory reserve; it has low capacity for oxygen reserve, and this makes it to heavily depend on aerobic respiration. Any event that will alter its circulatory process and interfere with the aerobic respiration can cause damage to the brain cells. However, the abundant collateral circulation in the brain ensures that the effect of the damage is limited to some parts of the brain.
The events that bring about the alteration or impairment in blood circulation in the brain come in two ways: ischemia and hemorrhage. Ischemia is usually in the form of thrombosis in large and small vessels, embolism with or without cardiac and/or arterial factor, systematic hypoperfusion, and venous thrombosis. The mechanism of brain cell damage due to ischemia is through depletion of oxygen and glucose with attendant reduced capacity to produce energy-releasing compounds such as the adenosine triphosphate (ATP) [10]. The molecule ATP is important for cellular metabolic processes. This creates a vicious cycle of lack of essential molecules such as oxygen and glucose for the survival of the cells and eventually causes cellular death. The extent of the damage is, however, a factor of the location, severity, and the duration of ischemia. That is to say, the longer the duration of the ischemia, the more extensive the damage will be.
The mechanisms of cellular death due to ischemia often come in many ways. One of these ways comes through the damage or dysfunction of the mitochondria. The mitochondria are the energy storage or power house of the cells [11]. Dysfunction or damage of the mitochondria will result in depletion of energy required to initiate and sustain physiologic processes such as the normal function of ion gradient, which results in ionic imbalance. The ionic imbalance pertains to the loss of potassium in exchange of sodium, chloride, and calcium ions [12]. This ionic imbalance leads to intracellular accumulation of fluid, which manifests as swelling of neuronal cells and glia that will eventually lead to the death of these cells. Another way in which neuronal cell death can occur due to ischemia is through excessive release of excitatory neurotransmitters such as the glutamate and aspartate. These neurotransmitters release will further complicate the damage to the brain cells. Other ways through which cellular death occur include production of oxygen-free radicals and reactive oxygen species (ROS), and apoptosis. Free radicals and the ROS react with a number of cellular and extracellular elements including the vascular endothelium and cause cell death. Apoptosis occurs in response to release of proapoptotic molecules such as cytochrome c and apoptosis-inducing factor from mitochondria due to gene expression of Bcl-2 and p53.
The whole process resembles blocking the water supply to a flower. If the blockage continues, the flower begins to shrink gradually and eventually dies off. Thus, whatever the pathophysiologic process that takes place, the result is that ischemia or reperfusion causes cell death, and this in turn causes impairment in brain functions [13]. The pathophysiologic process of stroke is simplified in Figure 1.
Schematic representation of pathophysiology of stroke and its consequences.
Many people around the world suffer stroke. According to the World Heart Federation, annually about 15 million people suffer stroke, out of which about 40% die and 33.33% live with long-term disability [14]. This shows that about 60% survives stroke probably due to improved stroke management over the last few decades. Equally, the percentage of those who live with long-term disability also calls for public health concern. Thus, improving rehabilitation services for stroke survivors is much needed. However, the incidence of stroke seems to vary between different regions of the world. In many developed countries, the incidence of stroke is declining even though the actual number of strokes is increasing because of the aging population [14, 15]. In contrast, in the developing countries, the incidence of stroke is increasing. For example, about 1.3 million people suffer stroke every year with about 75% surviving it, and the incidence is predicted to increase with high incidence of death in Latin America, the Middle East, and sub-Saharan Africa in a few decades to come probably due to lack of standard care for stroke [14].
Many factors can put one at the risk of developing stroke. The risk factors for stroke can be divided into modifiable and nonmodifiable ones. The modifiable risk factors include high blood pressure, heart disease, hypercholesterolemia, physical inactivity, smoking, alcohol consumption, diabetes mellitus, psychosocial stress and depression, and kidney diseases [16]. The nonmodifiable risk factors include gender, race, and genetic factors. For gender as a nonmodifiable risk factor, there are varied reports on whether stroke occurs more in women or men and vice versa, though they are mostly in favor of high incidence in women. According to a study by Petrea and colleagues, stroke occurs more in women than men, though there is no significant difference between men and women in terms of stroke severity, subtype, and case fatality [17]. These variations may probably represent the social structure of a given population. Consequently, the incidence between men and women may be because of one gender reporting to the clinic more than the other in a given population. Secondly, the distribution of gender in the population can also play a role. In addition to all that was mentioned, women tend to have poorer functional outcomes following stroke [18]. Furthermore, whatever the cause of a stroke, its incidence imposes a huge financial burden on patients and their families and can cost governments millions of dollars as direct and indirect costs depending on the country and the particular healthcare system.
Stroke results in impairment of brain functions, cognitive, motor, and sensory/perceptual functions [13]. Examples of these impairments include decreased movement quality, impaired movement coordination, gait and balance problems, vascular dementia, memory impairment, emotional disturbances, and hemispatial neglect. The motor impairment is significant since movement is important for humans’ daily functioning. The consequences of impairment of brain functions following stroke include difficulty in carrying out activities of daily living such as washing, dressing, bathing and difficulty in carrying out previously enjoyed leisure activities [19]. Normal functions of the brain are required in our daily life activities and participation. Therefore, rehabilitation is important to help patient recover or live an independent life as much as possible. In physiotherapy practice, CIMT is used for the rehabilitation of movement impairment after stroke.
One of the major functions of the nervous system is the control of human movement, which is essential for our daily functioning and participation. This control occurs in top-down, bottom-up, and parallel manner using different parts of the central nervous system. The CNS structures responsible for the control of human movement include the cerebral cortex, basal ganglia, brainstem, cerebellum, and thalamus that are contained in the diencephalon and spinal cord, which are complemented by the peripheral feedback [20, 21]. The functions of these various structures are summarized in Figure 2.
Schematic representation of nervous control of human movement. PM, premotor cortex; MC, motor cortex; M1, primary motor cortex.
The cerebral cortex functions for cognition, perception, and behavior. The cerebral cortex integrates these aforementioned functions to help execute human movements. It consists mainly of three important structures that are closely related with each other, the motor cortex, the premotor area, and the primary motor area. The main function of the motor cortex is sending inputs/commands through the corticospinal tract and corticobulbar system to the brainstem and the spinal cord [20]. The premotor area functions alongside other parts of the brain in movement programming, selection of what to do, and identification of objects in space [20, 22]. It sends most of its outputs directly to the motor cortex, and some to the brainstem and the spinal cord [23]. The basal ganglia are a collection of nuclei at the base of the brain that are involved in higher-order cognitive functions like planning the strategies of movement [24]. These nuclei receive inputs from most parts of the cerebral cortex and send back their outputs to the motor cortex by the way of the thalamus.
The brainstem is important for the control of posture and locomotion. Postural control is essential for proper execution of movement. This is possible due to the presence of important nuclei in the brainstem, which include vestibular nuclei, red nuclei, and reticular nuclei [20, 21]. The brainstem receives somatosensory inputs from the skin and muscles of the head and sensory inputs from the vestibular and visual systems. Similarly, nuclei in the brainstem control outputs to the neck, face, and eyes. The cerebellum receives inputs from the spinal cord and the cerebral cortex detailing about movement and planning of movement, respectively. In addition, it sends output to the brainstem. The main functions of the cerebellum are comparing the intended movement with sensory signals and update the movement commands when the movement goes abnormally. Secondly, it helps in modulating range and force of movements. The thalamus is contained in the diencephalon, and most of the outputs from the basal ganglia, the spinal cord, the brainstem, and the cerebellum are processed via it. The spinal cord is at the lower level of the movement control hierarchy. It receives somatosensory information from the muscles, joints, and skin and sends information to the higher centers. However, following stroke, the functions of these various structures of the brain become impaired in such a way that movement is no longer well planned, coordinated, modulated, and integrated. The aim of rehabilitation is to reestablish these various integrated functions for normal movement control. Consequently, constraint-induced movement therapy (CIMT) is used to reestablish the normal nervous control of human movement.
Movement is important in every human’s endeavors; it is essential for the performance of most of our daily activities. However, after a stroke, our ability to move may be impaired. This is due to the impairment in normal movement control as a result of damage to some areas of the brain. To help reestablish normal movement control following stroke, constraint-induced movement therapy is used [25, 26]. Constraint-induced movement therapy (CIMT) is a movement rehabilitation technique, which aims to counteract learned nonuse acquired after stroke [26, 27]. The learned nonuse phenomenon is an acquired behavior exhibited by patients following stroke that makes them not to use the affected limb in functional activities. It is said to be due to failure to carry out tasks after unsuccessful attempts as a result of depression of functions of the central nervous system, pain or fatigue following the injury. This acquired behavior may set off a vicious cycle of impairments comprising of decreased movement, decreased cortical representation of the affected part of the body, and compensatory behavior that may also decrease use of the affected part [28]. The mechanisms of learned nonuse phenomenon are depicted in Figure 3. Please refer to the articles by Taub and his colleagues for more details on the learned nonuse [27, 28]. Although, the description of the learned nonuse phenomenon by Taub has been challenged, modified, and expanded to include psychosocial and structural factors that can lead to the acquired behavior [29], his explanation has provided researchers and clinicians with the foundation for designing restorative rehabilitation techniques enabling people with stroke regain functions. The examples of these techniques have been seen in forced use and CIMT.
The learned nonuse phenomenon (reproduced with permission from Edward Taub).
The origin of CIMT has been credited to the work of Edward Taub, though he acknowledged previous researchers’ contribution to the understanding of this phenomenon [25]. Here, monkeys received surgical abolition of somatic sensation of one or the two forelimbs. Thereafter, they were trained based on some learning principles. The abolition of somatic sensation conditioned the monkeys to never use the limbs again. However, the animals were forced to use the affected limb as soon as the unaffected limb is constrained. Additionally, it was noted that the use of the affected limb was further strengthened when the animal was rewarded with food after a successful attempt. The use of the limb was achieved through breaking task into manageable components in a process known as shaping. Subsequently, this protocol was first translated to a patient with chronic stroke in which his unaffected upper limb was constrained for about 90% of the waking hours and patients with chronic stroke and brain injury [26, 30]. This variant of CIMT is known as forced use. The current and widely used variant of CIMT was started on chronic patients who received constraint of the unaffected limb for 90% of the waking hours and task practice with the affected limb for 6 h for 10 days [27]. So far, there are many variants of CIMT in forms of randomized controlled trials (RCT), single case experimental studies, case reports, and so forth. In fact, as of now, there are not less than 500 studies of CIMT including a highly rigorous multicenter RCT known as the EXCITE trial [31].
In addition to the explanations above, thus far CIMT has been extended to the rehabilitation of many conditions such as cerebral palsy, brachial plexus injury, spinal cord injury, multiple sclerosis, aphasia, and hearing impairments [32, 33, 34, 35, 36]. All these reported improvement in the outcomes of interest. Furthermore, currently CIMT is used for both upper and lower limbs [37, 38]. However, the studies in lower limbs are still few, and therefore, more studies need to be carried out to determine the effect of CIMT in lower limb motor impairment after stroke. This will help in translating the opportunities gained with upper limb CIMT and possibly further researchers’ understanding of the mechanisms of recovery of motor function following stroke.
The basic components of CIMT include repetitive task/shaping practice with the affected limb, constraint of the unaffected limb, and transfer package [39]. Task practice involves carrying out the usual everyday tasks or activities such as brushing, cooking, washing plates, playing tennis, kicking or throwing a ball, and picking up a cup and taking it to the mouth to drink from it [40, 41]. In shaping practice, similar tasks as in task practice are carried out; however, they are broken down into manageable components in which the participant will have to master a component before proceeding to another [40, 41, 42]. For example, when a participant is to learn how to pick up a cup and take it to the mouth to drink from it, he will be taught to learn how to grasp the cup, then pick it up, and the rest follows. Constraining the unaffected limb involves use of slings, mitts, or any possibly practicable orthotic device to prevent the use of the limb [42]. Sometimes, this can be achieved through conscious restriction of the use of the unaffected limb by the patient. The transfer package is any method used to foster compliance with task/shaping practice and the constraint components of CIMT [41]. The methods used include the use of logbook, diary, everyday administration of motor activity log, monitoring by caregivers, and practice outside the laboratory (e.g., at home).
In the literature, importance of repetitive task/shaping practice in being an essential component responsible for improvement following CIMT has been underscored. However, according to Taub and colleagues, transfer package is very key to improvement in function following CIMT [43]. This finding probably confirms the importance of task or shaping repetition as transfer package is meant to foster compliance and use of the affected limb outside laboratory. In essence, transfer package helps to achieve more repetition. Similarly, constraint ensures that use of the constrained limb is restricted, while the use of the affected limb is maximized. This is also akin to encouraging more repetitions with the affected limb. Pooling all these arguments together, we can see that the other components of CIMT, constraint, and transfer package work to provide high repetition of task or shaping practice. This is more especially that it has been reported for the upper limbs that there was no significant difference whether constraint is used or not during CIMT [44]. However, studies on CIMT for the lower limb need to determine whether use of constraint is necessary, tolerable, or even practicable. Some studies on upper limb have indicated some compliance or tolerability of the participants with constraint [45, 46].
Constraint-induced movement therapy has evolved over the years to have many different protocols. The protocols involve either modification of the task/shaping practice, constraint or both components of CIMT; or even the process or setting of its administration. These protocols include using hours as measure of intensity of task/shaping practice, using number of repetitions as measure of intensity of task/shaping practice, home-based CIMT, use of automated constraint-induced therapy extension (AutoCITE), and CIMT without constraint [38, 47, 48, 49, 50]. See Table 1 for the details of these different protocols. The protocol that uses number of repetitions is relatively a new approach. Therefore, its details are represented in Table 2.
Protocol | Task/shaping practice | Constraint | Transfer package |
---|---|---|---|
Use of hours | Practice for 0.5–6 h for ≥ 10 days | Constraint for 2 h or more or for 90% of the waking hours | Logbook, diary, everyday administration of motor activity log, monitoring by caregivers, practicing at home, etc. |
Without constraint | Same as above | No any constraint | Same as above |
Home-based CIMT | Same as above, but practice is done at home | Same as above | Same as above |
Use of AutoCITE | Same as in use of hours, but practice is administered through the use of a computerized mechanical system | Same as above | Same as above |
Use of number of repetitions | 300–600 repetitions in two or three sessions per day | Constraint for 90% of the waking hours | Same as above |
Different protocols of CIMT.
Tasks | No. of repetitions per session | No. of sessions per day | No. of days per week | No. of weeks |
---|---|---|---|---|
(1) Writing the letter A | 20 | 2 or 3 | 5 or 7 | 2 or more |
(2) Picking up a cup, taking it to the mouth, and drinking from it | 20 | 2 or 3 | 5 or 7 | 2 or more |
(3) Drawing a circle | 20 | 2 or 3 | 5 or 7 | 2 or more |
(4) Transferring an object from one place to another on a table | 20 | 2 or 3 | 5 or 7 | 2 or more |
(5) Imitation of teeth brushing with the middle or the index finger | 20 | 2 or 3 | 5 or 7 | 2 or more |
Example of the protocols of tasks/shaping practice for the CIMT using number of repetitions.
One of the concerns about the standard CIMT is the issue of compliance since it seems to have a long duration of tasks/shaping practice of 6 h or less [51]. However, studies such as those by Kaplon and his colleagues and Stock and his colleagues have all indicated that the time spent practicing task/shaping fell short of what is being claimed [52, 53]. Additionally, many studies have shown that the shorter duration CIMT, the protocol that uses less than or 3 h of task/shaping practice, provides better outcomes [54, 55]. In contrast, the protocol using number of repetition has been touted to be feasible, easier, and may provide better compliance and complements the transfer package component as it takes on the elements of self-management [45, 56]. Recently, it has been shown to be as effective as the one using number of hours [48, 49]. Furthermore, a virtual reality-amplified arm training of just 30 minutes proved very effective at improving motor outcomes at 6 weeks postintervention and 3 months follow-up [57]. This technique known as reinforcement-induced therapy uses virtual reality system with the sole aim of optimizing proper practice with the affected arm during rehabilitation. Similarly, an automated delivery of CIMT has been used [51]. This form of delivery of CIMT is aimed at fostering compliance with the CIMT protocol. Therefore, the goal of future CIMT protocols should be aimed at improving compliance in order to achieve the massed practice of the technique. This type of protocol as reported in some previous studies can be administered in the form of a distributed practice [48, 58]. A distributed practice is a type of practice in which the practice is divided into sessions per day [42]. Probably, distributed practice will help do away with overwhelm; fatigue and possibly anxiety patients may have and help encourage them perform the required intensity of practice per day.
Effectiveness of a given rehabilitation intervention can be said to be sound if it is evaluated on different outcomes. This will enable the intervention to have a strong theoretical basis. For CIMT, its effects have been investigated on impairments such as neurophysiological and behavioral, real-world arm use, motor function, activities of daily living, quality of life, and kinematics [31, 55, 59, 60, 61, 62, 63, 64]. Recently, it has been demonstrated that neurophysiological changes following CIMT well correlate with motor function [48, 64]. The examples of effects of CIMT and the effects based on the International Classification of Functioning, Disability and Health (ICF) model are summarized in Table 3 and Figure 4, respectively. These effects are measured using outcome measures such as Wolf motor function test (WMFT), action research arm test (ARAT), nine peg hole test (NPHT), motor activity log (MAL), motor function subscale of Fugl-Meyer assessment (FM), upper limb self-efficacy test (UPSET), functional magnetic resonance imaging (fMRI), and transmagnetic stimulation (TMS) [27, 30, 65, 66, 67, 68, 69, 70, 71, 72]. The WMFT, the ARAT, the FM, and the JPHT are measures of motor function [30, 68, 69, 73]. The fMRI and TMS are measures of neurophysiological functions [70, 72]. The MAL is a measure of real-world arm use [27, 70, 71]. The UPSET is a measure of confidence in the use of the upper limb after stroke [67]. However, the effects are restricted to only those who have mild to moderate impairment. Consequently, the inclusion criteria used during CIMT include patients who have 10° and 30° of interphalangeal and wrist joints extension, respectively, or those that have some level of motor activity enough to enable them practice some tasks with the limb [40, 59, 73]. Thus, the existing protocol of CIMT is not a one size fits all kind of rehabilitation technique, though the need to investigate how its application can be extended to all forms of degree or level of impairment arises.
Effects | Examples |
---|---|
Neurophysiological effects | Increase in gray matter, increase in cortical map, increase in cortical activation, decreased transcallosal inhibition, improvement in central conduction time, improvement in resting motor threshold, and prolongation of cortical silent period |
Kinematics | Efficient temporal and spatial movements, improved preplanned movement and control |
Behavioral | Improved real-world arm use, improved use of the hand in activities requiring fine motor control, improved motor function, improved gait and balance |
Effects of constraint-induced movement therapy (CIMT).
Schematic representation of the effects of constraint-induced movement therapy (CIMT) in stroke patients. ADL, activities of daily living.
At the moment, CIMT is administered only to the patients who have mild to moderate impairment. These are those who can to some extent perform some motor activity with the affected part. However, it is possible to integrate mental practice and motor imagery in the existing protocols of CIMT for the benefits of those with severe impairment bearing in mind the neurophysiological effect of CIMT and its relationship with motor function [64], and the role of mirror neurons when actions of a second or third person are observed or when task performance is imagined [74]. This perspective is for the benefit of those who may have severe impairment—those who do not have any appreciable motor activity enough to enable them perform any task. These forms of CIMT may be called passive CIMT (pCIMT) and imagery CIMT (iCIMT), respectively. For the pCIMT, the task/shaping practice should be carried out in high repetition with the affected limb similar to the repetition in the standard CIMT, and the unaffected limb should be constrained for 90% of the waking hours or less depending on the therapist’s clinical decision. However, the transfer package component may be initiated or deferred until the patients improve in their motor ability that they can use to practice. This too depends on the therapist’s clinical decision and reasoning. Similarly, for the iCIMT, the patient should be made to observe a second person or third person performing task/shaping practice to the required number of repetition as in the normal CIMT protocol. Here, the unaffected limb may or may not be constrained.
Another possible perspective is to use the number of repetition as a measure of intensity of task/shaping practice during CIMT. Already, there are indications that these types of protocols seem to be easier and have similar effectiveness compared to the one using number of hours [48, 49]. This is because number of repetition of task is important for motor recovery [45, 51, 58].
Mr. MM is a 67-year-old community dwelling man who had a stroke 10 days earlier. Before his stroke, he was a very active subsistent farmer. He woke up the morning he had the stroke and realized that he was unable to move any part of his body. Upon realizing his condition, his family rushed him to a nearby secondary health facility where he was diagnosed with a stroke and started receiving care accordingly. According to clinical assessments and reports, he had ischemic stroke involving the left hemisphere. Mr. MM’s main presentations were inability to sit or stand and walk without help from the formal or informal caregivers, and inability to use his right upper limb for any activity. Other presentations include inability to maintain his position in sitting without help.
In order to design a rehabilitation program using CIMT say for the upper limb for this patient, we need to first of all identify his problems. We can identify his problem by assessing his level of activity with the upper limb using, for example, Wolf motor function test or motor activity log, and being aware of the degree of freedom at the joints of the upper limb [27, 31]. Similarly, we can assess the range of motion (ROM) in the individual joints and assess the limb for spasticity, for instance, using modified Ashworth scale (MAS) [75]. Thereafter, we can develop alternative protocols of CIMT for him. For instance, we can decide to plan 6 h or less of task/shaping practice for the right limb with constraint for 90% or less of the waking hours, or we can plan for 300 or more of task/shaping practice for the right limb with constraint for 90% or less of the waking hours divided into two or more sessions per day. Additionally, we may decide to manage the patient at home, in the clinic, or provide him with the skills to self-manage. In particular, self-management is important for positive outcomes after stroke [76, 77].
After making an informed clinical decision on the choice of the best alternative or protocol, we can then administer it and reassess or monitor and evaluate its progress after sometime. If it works fine, we can decide to continue with it; if it does not provide any appreciable outcome, we can decide to choose another alternative protocol. This is the clinical reasoning. However, the existing studies on CIMT do not especially emphasize on clinical reasoning, rather they give a straightjacket prescription of what should be done throughout the period of care whether the patients improve better or not. Clinical reasoning is important to physiotherapy practice [78]. The process of problem solving, clinical decision making, and clinical reasoning in constraint-induced movement therapy is represented in Figure 5.
Problem solving, clinical decision making, and clinical reasoning in CIMT.
Constraint-induced movement therapy (CIMT) plays a major role in the rehabilitation of movement after stroke. Its effects range from improved real-world use of the arm, motor function, neurophysiological functions, kinematics, and quality of life. The problem is that CIMT is not done for all categories of patients with stroke. It is done for only those with mild to moderate impairment. Additionally, there are varied protocols of CIMT. Some protocols use number of hours and some others use number of repetitions of tasks/shaping practice. The protocols that use number of hours of task practice are not clear and are resource intensive, and as such, they could interfere with the process of clinical decision making. Consequently, the use of number of repetitions of task practice to determine the intensity or the amount of task practice may be more appropriate. Secondly, there is a need to extend the use of CIMT application to those patients with severe impairments after stroke probably by asking the patients to wear constraint on the unaffected limb and imagine they are practicing tasks with the affected limb. However, skills in problem solving, clinical decision making, and clinical reasoning are required by the physiotherapist in order to make an effective use of CIMT. These skills may be acquired through reflective practice and continuing professional development.
The author does not have any conflict of interest to declare.
Content alerts
",metaTitle:"Content alerts",metaDescription:"Content alerts",metaKeywords:null,canonicalURL:"/page/content-alerts",contentRaw:'[{"type":"htmlEditorComponent","content":"Content alerts
\\n"}]'},components:[{type:"htmlEditorComponent",content:"Content alerts
\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:null},{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:null},{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:"Vienna University of Technology",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.\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:null},{id:"62389",title:"PhD.",name:"Ali Demir",middleName:null,surname:"Sezer",slug:"ali-demir-sezer",fullName:"Ali Demir Sezer",position:"Assist. Prof.",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:null},{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:null},{id:"64434",title:"Dr.",name:"Angkoon",middleName:null,surname:"Phinyomark",slug:"angkoon-phinyomark",fullName:"Angkoon Phinyomark",position:"Postdoctoral researcher",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:"University Joseph Fourier (Grenoble I)",country:null}},{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:null}],filtersByRegion:[{group:"region",caption:"North America",value:1,count:451},{group:"region",caption:"Middle and South America",value:2,count:605},{group:"region",caption:"Africa",value:3,count:199},{group:"region",caption:"Asia",value:4,count:1081},{group:"region",caption:"Australia and Oceania",value:5,count:75},{group:"region",caption:"Europe",value:6,count:1470}],offset:12,limit:12,total:103552},chapterEmbeded:{data:{}},editorApplication:{success:null,errors:{}},ofsBooks:{filterParams:{topicId:"156"},books:[{type:"book",id:"7404",title:"Hystersis of Composites",subtitle:null,isOpenForSubmission:!0,hash:"e703f836282435b95fb7d1c1efb86fc2",slug:null,bookSignature:"Dr. Li Longbiao",coverURL:"https://cdn.intechopen.com/books/images_new/7404.jpg",editedByType:null,editors:[{id:"260011",title:"Dr.",name:"Li",surname:"Longbiao",slug:"li-longbiao",fullName:"Li Longbiao"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],filtersByTopic:[{group:"topic",caption:"Agricultural and Biological Sciences",value:5,count:29},{group:"topic",caption:"Biochemistry, Genetics and Molecular Biology",value:6,count:31},{group:"topic",caption:"Business, Management and Economics",value:7,count:7},{group:"topic",caption:"Chemistry",value:8,count:32},{group:"topic",caption:"Computer and Information Science",value:9,count:20},{group:"topic",caption:"Earth and Planetary Sciences",value:10,count:8},{group:"topic",caption:"Engineering",value:11,count:92},{group:"topic",caption:"Environmental Sciences",value:12,count:12},{group:"topic",caption:"Immunology and Microbiology",value:13,count:10},{group:"topic",caption:"Materials Science",value:14,count:20},{group:"topic",caption:"Mathematics",value:15,count:6},{group:"topic",caption:"Medicine",value:16,count:99},{group:"topic",caption:"Nanotechnology and Nanomaterials",value:17,count:8},{group:"topic",caption:"Neuroscience",value:18,count:4},{group:"topic",caption:"Pharmacology, Toxicology and Pharmaceutical Science",value:19,count:2},{group:"topic",caption:"Physics",value:20,count:16},{group:"topic",caption:"Psychology",value:21,count:1},{group:"topic",caption:"Robotics",value:22,count:3},{group:"topic",caption:"Social Sciences",value:23,count:16},{group:"topic",caption:"Technology",value:24,count:8},{group:"topic",caption:"Veterinary Medicine and Science",value:25,count:1},{group:"topic",caption:"Composite Materials",value:156,count:1}],offset:12,limit:12,total:1},popularBooks:{featuredBooks:[{type:"book",id:"8122",title:"Vectors and Vector-Borne Zoonotic Diseases",subtitle:null,isOpenForSubmission:!1,hash:"5a088c3ab82e499c8d5d2f8ceec6a601",slug:"vectors-and-vector-borne-zoonotic-diseases",bookSignature:"Sara Savić",coverURL:"https://cdn.intechopen.com/books/images_new/8122.jpg",editors:[{id:"92185",title:"Dr.",name:"Sara",middleName:null,surname:"Savic",slug:"sara-savic",fullName:"Sara Savic"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7486",title:"Advanced Sorption Process Applications",subtitle:null,isOpenForSubmission:!1,hash:"bc77a8d4e58d7c7eb4d2137adb0f0f34",slug:"advanced-sorption-process-applications",bookSignature:"Serpil Edebali",coverURL:"https://cdn.intechopen.com/books/images_new/7486.jpg",editors:[{id:"223744",title:"Dr.",name:"Serpil",middleName:null,surname:"Edebali",slug:"serpil-edebali",fullName:"Serpil Edebali"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7694",title:"Simulation Modelling Practice and Theory",subtitle:null,isOpenForSubmission:!1,hash:"f955d03d619f68fec7b6f3518e792e6f",slug:"simulation-modelling-practice-and-theory",bookSignature:"Evon Abu-Taieh and Asim Abdel El Sheikh Ahmed",coverURL:"https://cdn.intechopen.com/books/images_new/7694.jpg",editors:[{id:"223522",title:"Dr.",name:"Evon",middleName:"M.O.",surname:"Abu-Taieh",slug:"evon-abu-taieh",fullName:"Evon Abu-Taieh"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"6797",title:"Chalcogen Chemistry",subtitle:null,isOpenForSubmission:!1,hash:"721946bc223c90085bafaf501d5b7329",slug:"chalcogen-chemistry",bookSignature:"Peter Papoh Ndibewu",coverURL:"https://cdn.intechopen.com/books/images_new/6797.jpg",editors:[{id:"87629",title:"Prof.",name:"Peter",middleName:"Papoh",surname:"Ndibewu",slug:"peter-ndibewu",fullName:"Peter Ndibewu"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"2160",title:"MATLAB",subtitle:"A Fundamental Tool for Scientific Computing and Engineering Applications - Volume 1",isOpenForSubmission:!1,hash:"dd9c658341fbd264ed4f8d9e6aa8ca29",slug:"matlab-a-fundamental-tool-for-scientific-computing-and-engineering-applications-volume-1",bookSignature:"Vasilios N. Katsikis",coverURL:"https://cdn.intechopen.com/books/images_new/2160.jpg",editors:[{id:"12289",title:"Prof.",name:"Vasilios",middleName:"N.",surname:"Katsikis",slug:"vasilios-katsikis",fullName:"Vasilios Katsikis"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"3568",title:"Recent Advances in Plant in vitro Culture",subtitle:null,isOpenForSubmission:!1,hash:"830bbb601742c85a3fb0eeafe1454c43",slug:"recent-advances-in-plant-in-vitro-culture",bookSignature:"Annarita Leva and Laura M. R. Rinaldi",coverURL:"https://cdn.intechopen.com/books/images_new/3568.jpg",editors:[{id:"142145",title:"Dr.",name:"Annarita",middleName:null,surname:"Leva",slug:"annarita-leva",fullName:"Annarita Leva"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"1770",title:"Gel Electrophoresis",subtitle:"Principles and Basics",isOpenForSubmission:!1,hash:"279701f6c802cf02deef45103e0611ff",slug:"gel-electrophoresis-principles-and-basics",bookSignature:"Sameh Magdeldin",coverURL:"https://cdn.intechopen.com/books/images_new/1770.jpg",editors:[{id:"123648",title:"Dr.",name:"Sameh",middleName:null,surname:"Magdeldin",slug:"sameh-magdeldin",fullName:"Sameh Magdeldin"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"632",title:"Wide Spectra of Quality Control",subtitle:null,isOpenForSubmission:!1,hash:"9f7ce64f86daee44a8c5604e8924de1c",slug:"wide-spectra-of-quality-control",bookSignature:"Isin Akyar",coverURL:"https://cdn.intechopen.com/books/images_new/632.jpg",editors:[{id:"36323",title:"Dr.",name:"Isin",middleName:null,surname:"Akyar",slug:"isin-akyar",fullName:"Isin Akyar"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7452",title:"Microbiology of Urinary Tract Infections",subtitle:"Microbial Agents and Predisposing Factors",isOpenForSubmission:!1,hash:"e99363f3cb1fe89c406f4934a23033d0",slug:"microbiology-of-urinary-tract-infections-microbial-agents-and-predisposing-factors",bookSignature:"Payam Behzadi",coverURL:"https://cdn.intechopen.com/books/images_new/7452.jpg",editors:[{id:"45803",title:"Ph.D.",name:"Payam",middleName:null,surname:"Behzadi",slug:"payam-behzadi",fullName:"Payam Behzadi"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"3037",title:"MATLAB",subtitle:"A Fundamental Tool for Scientific Computing and Engineering Applications - Volume 3",isOpenForSubmission:!1,hash:"1de63ac4f2c398a1304a7c08ee883655",slug:"matlab-a-fundamental-tool-for-scientific-computing-and-engineering-applications-volume-3",bookSignature:"Vasilios N. Katsikis",coverURL:"https://cdn.intechopen.com/books/images_new/3037.jpg",editors:[{id:"12289",title:"Prof.",name:"Vasilios",middleName:"N.",surname:"Katsikis",slug:"vasilios-katsikis",fullName:"Vasilios Katsikis"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"2175",title:"Risk Management",subtitle:"Current Issues and Challenges",isOpenForSubmission:!1,hash:"c6406ba890ef4569efd8298e1121685d",slug:"risk-management-current-issues-and-challenges",bookSignature:"Nerija Banaitiene",coverURL:"https://cdn.intechopen.com/books/images_new/2175.jpg",editors:[{id:"139414",title:"Dr.",name:"Nerija",middleName:null,surname:"Banaitiene",slug:"nerija-banaitiene",fullName:"Nerija Banaitiene"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"1667",title:"A Bird's-Eye View of Veterinary Medicine",subtitle:null,isOpenForSubmission:!1,hash:"7be827d70aa0311258d658f729670887",slug:"a-bird-s-eye-view-of-veterinary-medicine",bookSignature:"Carlos C. Perez-Marin",coverURL:"https://cdn.intechopen.com/books/images_new/1667.jpg",editors:[{id:"25632",title:"Dr.",name:"Carlos C.",middleName:null,surname:"Perez-Marin",slug:"carlos-c.-perez-marin",fullName:"Carlos C. Perez-Marin"}],productType:{id:"1",chapterContentType:"chapter"}}],offset:12,limit:12,total:1816},hotBookTopics:{hotBooks:[],offset:0,limit:12,total:null},publish:{},publishingProposal:{success:null,errors:{}},books:{featuredBooks:[{type:"book",id:"8122",title:"Vectors and Vector-Borne Zoonotic Diseases",subtitle:null,isOpenForSubmission:!1,hash:"5a088c3ab82e499c8d5d2f8ceec6a601",slug:"vectors-and-vector-borne-zoonotic-diseases",bookSignature:"Sara Savić",coverURL:"https://cdn.intechopen.com/books/images_new/8122.jpg",editors:[{id:"92185",title:"Dr.",name:"Sara",middleName:null,surname:"Savic",slug:"sara-savic",fullName:"Sara Savic"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7486",title:"Advanced Sorption Process Applications",subtitle:null,isOpenForSubmission:!1,hash:"bc77a8d4e58d7c7eb4d2137adb0f0f34",slug:"advanced-sorption-process-applications",bookSignature:"Serpil Edebali",coverURL:"https://cdn.intechopen.com/books/images_new/7486.jpg",editors:[{id:"223744",title:"Dr.",name:"Serpil",middleName:null,surname:"Edebali",slug:"serpil-edebali",fullName:"Serpil Edebali"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7694",title:"Simulation Modelling Practice and Theory",subtitle:null,isOpenForSubmission:!1,hash:"f955d03d619f68fec7b6f3518e792e6f",slug:"simulation-modelling-practice-and-theory",bookSignature:"Evon Abu-Taieh and Asim Abdel El Sheikh Ahmed",coverURL:"https://cdn.intechopen.com/books/images_new/7694.jpg",editors:[{id:"223522",title:"Dr.",name:"Evon",middleName:"M.O.",surname:"Abu-Taieh",slug:"evon-abu-taieh",fullName:"Evon Abu-Taieh"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"6797",title:"Chalcogen Chemistry",subtitle:null,isOpenForSubmission:!1,hash:"721946bc223c90085bafaf501d5b7329",slug:"chalcogen-chemistry",bookSignature:"Peter Papoh Ndibewu",coverURL:"https://cdn.intechopen.com/books/images_new/6797.jpg",editors:[{id:"87629",title:"Prof.",name:"Peter",middleName:"Papoh",surname:"Ndibewu",slug:"peter-ndibewu",fullName:"Peter Ndibewu"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"2160",title:"MATLAB",subtitle:"A Fundamental Tool for Scientific Computing and Engineering Applications - Volume 1",isOpenForSubmission:!1,hash:"dd9c658341fbd264ed4f8d9e6aa8ca29",slug:"matlab-a-fundamental-tool-for-scientific-computing-and-engineering-applications-volume-1",bookSignature:"Vasilios N. Katsikis",coverURL:"https://cdn.intechopen.com/books/images_new/2160.jpg",editors:[{id:"12289",title:"Prof.",name:"Vasilios",middleName:"N.",surname:"Katsikis",slug:"vasilios-katsikis",fullName:"Vasilios Katsikis"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"3568",title:"Recent Advances in Plant in vitro Culture",subtitle:null,isOpenForSubmission:!1,hash:"830bbb601742c85a3fb0eeafe1454c43",slug:"recent-advances-in-plant-in-vitro-culture",bookSignature:"Annarita Leva and Laura M. R. Rinaldi",coverURL:"https://cdn.intechopen.com/books/images_new/3568.jpg",editors:[{id:"142145",title:"Dr.",name:"Annarita",middleName:null,surname:"Leva",slug:"annarita-leva",fullName:"Annarita Leva"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"1770",title:"Gel Electrophoresis",subtitle:"Principles and Basics",isOpenForSubmission:!1,hash:"279701f6c802cf02deef45103e0611ff",slug:"gel-electrophoresis-principles-and-basics",bookSignature:"Sameh Magdeldin",coverURL:"https://cdn.intechopen.com/books/images_new/1770.jpg",editors:[{id:"123648",title:"Dr.",name:"Sameh",middleName:null,surname:"Magdeldin",slug:"sameh-magdeldin",fullName:"Sameh Magdeldin"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"632",title:"Wide Spectra of Quality Control",subtitle:null,isOpenForSubmission:!1,hash:"9f7ce64f86daee44a8c5604e8924de1c",slug:"wide-spectra-of-quality-control",bookSignature:"Isin Akyar",coverURL:"https://cdn.intechopen.com/books/images_new/632.jpg",editors:[{id:"36323",title:"Dr.",name:"Isin",middleName:null,surname:"Akyar",slug:"isin-akyar",fullName:"Isin Akyar"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"7452",title:"Microbiology of Urinary Tract Infections",subtitle:"Microbial Agents and Predisposing Factors",isOpenForSubmission:!1,hash:"e99363f3cb1fe89c406f4934a23033d0",slug:"microbiology-of-urinary-tract-infections-microbial-agents-and-predisposing-factors",bookSignature:"Payam Behzadi",coverURL:"https://cdn.intechopen.com/books/images_new/7452.jpg",editors:[{id:"45803",title:"Ph.D.",name:"Payam",middleName:null,surname:"Behzadi",slug:"payam-behzadi",fullName:"Payam Behzadi"}],productType:{id:"1",chapterContentType:"chapter"}},{type:"book",id:"3037",title:"MATLAB",subtitle:"A Fundamental Tool for Scientific Computing and Engineering Applications - Volume 3",isOpenForSubmission:!1,hash:"1de63ac4f2c398a1304a7c08ee883655",slug:"matlab-a-fundamental-tool-for-scientific-computing-and-engineering-applications-volume-3",bookSignature:"Vasilios N. Katsikis",coverURL:"https://cdn.intechopen.com/books/images_new/3037.jpg",editors:[{id:"12289",title:"Prof.",name:"Vasilios",middleName:"N.",surname:"Katsikis",slug:"vasilios-katsikis",fullName:"Vasilios Katsikis"}],productType:{id:"1",chapterContentType:"chapter"}}],latestBooks:[{type:"book",id:"7694",title:"Simulation Modelling Practice and Theory",subtitle:null,isOpenForSubmission:!1,hash:"f955d03d619f68fec7b6f3518e792e6f",slug:"simulation-modelling-practice-and-theory",bookSignature:"Evon Abu-Taieh and Asim Abdel El Sheikh Ahmed",coverURL:"https://cdn.intechopen.com/books/images_new/7694.jpg",editedByType:"Edited by",editors:[{id:"223522",title:"Dr.",name:"Evon",middleName:"M.O.",surname:"Abu-Taieh",slug:"evon-abu-taieh",fullName:"Evon Abu-Taieh"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7695",title:"Green Energy Advances",subtitle:null,isOpenForSubmission:!1,hash:"ca498ae0f824bac0c43f5cfb011d8e9c",slug:"green-energy-advances",bookSignature:"Diana Enescu",coverURL:"https://cdn.intechopen.com/books/images_new/7695.jpg",editedByType:"Edited by",editors:[{id:"226207",title:"Ph.D.",name:"Diana",middleName:null,surname:"Enescu",slug:"diana-enescu",fullName:"Diana Enescu"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7199",title:"Charged Particles",subtitle:null,isOpenForSubmission:!1,hash:"c456f670b68b3512e9e9866f9837fd98",slug:"charged-particles",bookSignature:"Malek Maaza and Mahmoud Izerrouken",coverURL:"https://cdn.intechopen.com/books/images_new/7199.jpg",editedByType:"Edited by",editors:[{id:"192286",title:"Prof.",name:"Malek",middleName:null,surname:"Maaza",slug:"malek-maaza",fullName:"Malek Maaza"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7465",title:"Trends in Geomatics",subtitle:"An Earth Science Perspective",isOpenForSubmission:!1,hash:"a32ff40d6c47e2b545b92d5075508c9c",slug:"trends-in-geomatics-an-earth-science-perspective",bookSignature:"Rifaat Abdalla",coverURL:"https://cdn.intechopen.com/books/images_new/7465.jpg",editedByType:"Edited by",editors:[{id:"222877",title:"Dr.",name:"Rifaat",middleName:null,surname:"Abdalla",slug:"rifaat-abdalla",fullName:"Rifaat Abdalla"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6710",title:"Update on Multiple Myeloma",subtitle:null,isOpenForSubmission:!1,hash:"229a96a2de131b3ac67f9f41b91de8f8",slug:"update-on-multiple-myeloma",bookSignature:"Khalid Ahmed Al-Anazi",coverURL:"https://cdn.intechopen.com/books/images_new/6710.jpg",editedByType:"Edited by",editors:[{id:"37255",title:"Dr.",name:"Khalid Ahmed",middleName:null,surname:"Al-Anazi",slug:"khalid-ahmed-al-anazi",fullName:"Khalid Ahmed Al-Anazi"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7225",title:"Dam Engineering",subtitle:null,isOpenForSubmission:!1,hash:"a845c7ddd9193f56a6bc91bc22bc503d",slug:"dam-engineering",bookSignature:"Hasan Tosun",coverURL:"https://cdn.intechopen.com/books/images_new/7225.jpg",editedByType:"Edited by",editors:[{id:"79083",title:"Prof.",name:"Hasan",middleName:null,surname:"Tosun",slug:"hasan-tosun",fullName:"Hasan Tosun"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7486",title:"Advanced Sorption Process Applications",subtitle:null,isOpenForSubmission:!1,hash:"bc77a8d4e58d7c7eb4d2137adb0f0f34",slug:"advanced-sorption-process-applications",bookSignature:"Serpil Edebali",coverURL:"https://cdn.intechopen.com/books/images_new/7486.jpg",editedByType:"Edited by",editors:[{id:"223744",title:"Dr.",name:"Serpil",middleName:null,surname:"Edebali",slug:"serpil-edebali",fullName:"Serpil Edebali"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6722",title:"Acoustic Emission Technology for High Power Microwave Radar Tubes",subtitle:null,isOpenForSubmission:!1,hash:"ef80c9b4123e022ea69a4bf777088522",slug:"acoustic-emission-technology-for-high-power-microwave-radar-tubes",bookSignature:"Narayan R. Joshi, Ayax D. Ramirez, Stephen D. Russell and David W. Brock",coverURL:"https://cdn.intechopen.com/books/images_new/6722.jpg",editedByType:"Authored by",editors:[{id:"95431",title:"Dr.",name:"Narayan",middleName:"R.",surname:"Joshi",slug:"narayan-joshi",fullName:"Narayan Joshi"}],productType:{id:"3",chapterContentType:"chapter",authoredCaption:"Authored by"}},{type:"book",id:"7237",title:"Energy-Efficient Approaches in Industrial Applications",subtitle:null,isOpenForSubmission:!1,hash:"a7b403a3af7828987f078b91334839bb",slug:"energy-efficient-approaches-in-industrial-applications",bookSignature:"Murat Eyvaz, Abdülkerim Gok and Ebubekir Yüksel",coverURL:"https://cdn.intechopen.com/books/images_new/7237.jpg",editedByType:"Edited by",editors:[{id:"170083",title:"Dr.",name:"Murat",middleName:null,surname:"Eyvaz",slug:"murat-eyvaz",fullName:"Murat Eyvaz"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6991",title:"Neurons",subtitle:"Dendrites and Axons",isOpenForSubmission:!1,hash:"696489f55e1077935f47087fa3829b5f",slug:"neurons-dendrites-and-axons",bookSignature:"Gonzalo Emiliano Aranda Abreu and María Elena Hernández Aguilar",coverURL:"https://cdn.intechopen.com/books/images_new/6991.jpg",editedByType:"Edited by",editors:[{id:"72314",title:"Dr.",name:"Gonzalo Emiliano",middleName:null,surname:"Aranda Abreu",slug:"gonzalo-emiliano-aranda-abreu",fullName:"Gonzalo Emiliano Aranda Abreu"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}]},subject:{topic:{id:"1",title:"Physical Sciences, Engineering and Technology",slug:"physical-sciences-engineering-and-technology",parent:null,numberOfBooks:1946,numberOfAuthorsAndEditors:46663,numberOfWosCitations:36782,numberOfCrossrefCitations:20816,numberOfDimensionsCitations:57646},booksByTopicFilter:{topicSlug:"physical-sciences-engineering-and-technology",sort:"-publishedDate",limit:12,offset:0},booksByTopicCollection:[{type:"book",id:"9336",title:"Technology, Science and Culture",subtitle:"A Global Vision",isOpenForSubmission:!1,hash:"e1895103eeec238cda200b75d6e143c8",slug:"technology-science-and-culture-a-global-vision",bookSignature:"Sergio Picazo-Vela and Luis Ricardo Hernández",coverURL:"https://cdn.intechopen.com/books/images_new/9336.jpg",editedByType:"Edited by",editors:[{id:"293960",title:"Dr.",name:"Sergio",middleName:null,surname:"Picazo-Vela",slug:"sergio-picazo-vela",fullName:"Sergio Picazo-Vela"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6797",title:"Chalcogen Chemistry",subtitle:null,isOpenForSubmission:!1,hash:"721946bc223c90085bafaf501d5b7329",slug:"chalcogen-chemistry",bookSignature:"Peter Papoh Ndibewu",coverURL:"https://cdn.intechopen.com/books/images_new/6797.jpg",editedByType:"Edited by",editors:[{id:"87629",title:"Prof.",name:"Peter",middleName:"Papoh",surname:"Ndibewu",slug:"peter-ndibewu",fullName:"Peter Ndibewu"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7486",title:"Advanced Sorption Process Applications",subtitle:null,isOpenForSubmission:!1,hash:"bc77a8d4e58d7c7eb4d2137adb0f0f34",slug:"advanced-sorption-process-applications",bookSignature:"Serpil Edebali",coverURL:"https://cdn.intechopen.com/books/images_new/7486.jpg",editedByType:"Edited by",editors:[{id:"223744",title:"Dr.",name:"Serpil",middleName:null,surname:"Edebali",slug:"serpil-edebali",fullName:"Serpil Edebali"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7199",title:"Charged Particles",subtitle:null,isOpenForSubmission:!1,hash:"c456f670b68b3512e9e9866f9837fd98",slug:"charged-particles",bookSignature:"Malek Maaza and Mahmoud Izerrouken",coverURL:"https://cdn.intechopen.com/books/images_new/7199.jpg",editedByType:"Edited by",editors:[{id:"192286",title:"Prof.",name:"Malek",middleName:null,surname:"Maaza",slug:"malek-maaza",fullName:"Malek Maaza"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7225",title:"Dam Engineering",subtitle:null,isOpenForSubmission:!1,hash:"a845c7ddd9193f56a6bc91bc22bc503d",slug:"dam-engineering",bookSignature:"Hasan Tosun",coverURL:"https://cdn.intechopen.com/books/images_new/7225.jpg",editedByType:"Edited by",editors:[{id:"79083",title:"Prof.",name:"Hasan",middleName:null,surname:"Tosun",slug:"hasan-tosun",fullName:"Hasan Tosun"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7273",title:"Advances in Heat Exchangers",subtitle:null,isOpenForSubmission:!1,hash:"be01a6ff85cfea7f4fcac6c4fafc4c13",slug:"advances-in-heat-exchangers",bookSignature:"Laura Castro Gómez and Víctor Manuel Velázquez Flores",coverURL:"https://cdn.intechopen.com/books/images_new/7273.jpg",editedByType:"Edited by",editors:[{id:"179471",title:"Dr.",name:"Laura",middleName:null,surname:"Castro Gómez",slug:"laura-castro-gomez",fullName:"Laura Castro Gómez"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7694",title:"Simulation Modelling Practice and Theory",subtitle:null,isOpenForSubmission:!1,hash:"f955d03d619f68fec7b6f3518e792e6f",slug:"simulation-modelling-practice-and-theory",bookSignature:"Evon Abu-Taieh and Asim Abdel El Sheikh Ahmed",coverURL:"https://cdn.intechopen.com/books/images_new/7694.jpg",editedByType:"Edited by",editors:[{id:"223522",title:"Dr.",name:"Evon",middleName:"M.O.",surname:"Abu-Taieh",slug:"evon-abu-taieh",fullName:"Evon Abu-Taieh"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7695",title:"Green Energy Advances",subtitle:null,isOpenForSubmission:!1,hash:"ca498ae0f824bac0c43f5cfb011d8e9c",slug:"green-energy-advances",bookSignature:"Diana Enescu",coverURL:"https://cdn.intechopen.com/books/images_new/7695.jpg",editedByType:"Edited by",editors:[{id:"226207",title:"Ph.D.",name:"Diana",middleName:null,surname:"Enescu",slug:"diana-enescu",fullName:"Diana Enescu"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7237",title:"Energy-Efficient Approaches in Industrial Applications",subtitle:null,isOpenForSubmission:!1,hash:"a7b403a3af7828987f078b91334839bb",slug:"energy-efficient-approaches-in-industrial-applications",bookSignature:"Murat Eyvaz, Abdülkerim Gok and Ebubekir Yüksel",coverURL:"https://cdn.intechopen.com/books/images_new/7237.jpg",editedByType:"Edited by",editors:[{id:"170083",title:"Dr.",name:"Murat",middleName:null,surname:"Eyvaz",slug:"murat-eyvaz",fullName:"Murat Eyvaz"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"7465",title:"Trends in Geomatics",subtitle:"An Earth Science Perspective",isOpenForSubmission:!1,hash:"a32ff40d6c47e2b545b92d5075508c9c",slug:"trends-in-geomatics-an-earth-science-perspective",bookSignature:"Rifaat Abdalla",coverURL:"https://cdn.intechopen.com/books/images_new/7465.jpg",editedByType:"Edited by",editors:[{id:"222877",title:"Dr.",name:"Rifaat",middleName:null,surname:"Abdalla",slug:"rifaat-abdalla",fullName:"Rifaat Abdalla"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}},{type:"book",id:"6722",title:"Acoustic Emission Technology for High Power Microwave Radar Tubes",subtitle:null,isOpenForSubmission:!1,hash:"ef80c9b4123e022ea69a4bf777088522",slug:"acoustic-emission-technology-for-high-power-microwave-radar-tubes",bookSignature:"Narayan R. Joshi, Ayax D. Ramirez, Stephen D. Russell and David W. Brock",coverURL:"https://cdn.intechopen.com/books/images_new/6722.jpg",editedByType:"Authored by",editors:[{id:"95431",title:"Dr.",name:"Narayan",middleName:"R.",surname:"Joshi",slug:"narayan-joshi",fullName:"Narayan Joshi"}],productType:{id:"3",chapterContentType:"chapter",authoredCaption:"Authored by"}},{type:"book",id:"7537",title:"Proceedings of the 4th International Conference on Innovations in Automation and Mechatronics Engineering (ICIAME2018)",subtitle:null,isOpenForSubmission:!1,hash:"d15b6794da3ef3b83f7bd72be3958397",slug:"proceedings-of-the-4th-international-conference-on-innovations-in-automation-and-mechatronics-engineering-iciame2018-",bookSignature:"Sanket N. Bhavsar, Anand Y. Joshi and Ketan M. Tamboli",coverURL:"https://cdn.intechopen.com/books/images_new/7537.jpg",editedByType:"Edited by",editors:[{id:"292329",title:"Dr.",name:"Sanket N.",middleName:null,surname:"Bhavsar",slug:"sanket-n.-bhavsar",fullName:"Sanket N. Bhavsar"}],productType:{id:"1",chapterContentType:"chapter",authoredCaption:"Edited by"}}],booksByTopicTotal:1946,mostCitedChapters:[{id:"10088",doi:"10.5772/8835",title:"Intention-Based Walking Support for Paraplegia Patients with Robot Suit HAL",slug:"intention-based-walking-support-for-paraplegia-patients-with-robot-suit-hal",totalDownloads:3887,totalCrossrefCites:11,totalDimensionsCites:181,book:{slug:"climbing-and-walking-robots",title:"Climbing and Walking Robots",fullTitle:"Climbing and Walking Robots"},signatures:"Kenta Suzuki, Gouji Mito, Hiroaki Kawamoto, Yasuhisa Hasegawa and Yoshiyuki Sankai",authors:null},{id:"17237",doi:"10.5772/24553",title:"Hydrogels: Methods of Preparation, Characterisation and Applications",slug:"hydrogels-methods-of-preparation-characterisation-and-applications",totalDownloads:61358,totalCrossrefCites:43,totalDimensionsCites:147,book:{slug:"progress-in-molecular-and-environmental-bioengineering-from-analysis-and-modeling-to-technology-applications",title:"Progress in Molecular and Environmental Bioengineering",fullTitle:"Progress in Molecular and Environmental Bioengineering - From Analysis and Modeling to Technology Applications"},signatures:"Syed K. H. Gulrez, Saphwan Al-Assaf and Glyn O Phillips",authors:[{id:"58120",title:"Prof.",name:"Saphwan",middleName:null,surname:"Al-Assaf",slug:"saphwan-al-assaf",fullName:"Saphwan Al-Assaf"}]},{id:"36171",doi:"10.5772/36942",title:"Research of Calcium Phosphates Using Fourier Transform Infrared Spectroscopy",slug:"research-of-calcium-phosphates-using-fourier-transformation-infrared-spectroscopy",totalDownloads:7280,totalCrossrefCites:37,totalDimensionsCites:140,book:{slug:"infrared-spectroscopy-materials-science-engineering-and-technology",title:"Infrared Spectroscopy",fullTitle:"Infrared Spectroscopy - Materials Science, Engineering and Technology"},signatures:"Liga Berzina-Cimdina and Natalija Borodajenko",authors:[{id:"110522",title:"Prof.",name:"Liga",middleName:null,surname:"Berzina-Cimdina",slug:"liga-berzina-cimdina",fullName:"Liga Berzina-Cimdina"},{id:"112181",title:"MSc.",name:"Natalija",middleName:null,surname:"Borodajenko",slug:"natalija-borodajenko",fullName:"Natalija Borodajenko"}]}],mostDownloadedChaptersLast30Days:[{id:"58215",title:"Vibration Simulation of Electric Machines",slug:"vibration-simulation-of-electric-machines",totalDownloads:1649,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"finite-element-method-simulation-numerical-analysis-and-solution-techniques",title:"Finite Element Method",fullTitle:"Finite Element Method - Simulation, Numerical Analysis and Solution Techniques"},signatures:"Marcel Janda and Kristyna Jandova",authors:[{id:"50093",title:"Dr.",name:"Kristyna",middleName:null,surname:"Jandova",slug:"kristyna-jandova",fullName:"Kristyna Jandova"},{id:"115806",title:"Dr.",name:"Marcel",middleName:null,surname:"Janda",slug:"marcel-janda",fullName:"Marcel Janda"}]},{id:"10042",title:"Superhydrophobicity, Learn from the Lotus Leaf",slug:"superhydrophobicity-learn-from-the-lotus-leaf",totalDownloads:8275,totalCrossrefCites:1,totalDimensionsCites:7,book:{slug:"biomimetics-learning-from-nature",title:"Biomimetics",fullTitle:"Biomimetics Learning from Nature"},signatures:"Mengnan Qu, Jinmei He and Junyan Zhang",authors:null},{id:"51031",title:"Face Recognition: Issues, Methods and Alternative Applications",slug:"face-recognition-issues-methods-and-alternative-applications",totalDownloads:3690,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"face-recognition-semisupervised-classification-subspace-projection-and-evaluation-methods",title:"Face Recognition",fullTitle:"Face Recognition - Semisupervised Classification, Subspace Projection and Evaluation Methods"},signatures:"Waldemar Wójcik, Konrad Gromaszek and Muhtar Junisbekov",authors:[{id:"24059",title:"Dr.Ing.",name:"Konrad",middleName:null,surname:"Gromaszek",slug:"konrad-gromaszek",fullName:"Konrad Gromaszek"}]},{id:"48982",title:"A Comprehensive Modeling and Simulation of Power Quality Disturbances Using MATLAB/SIMULINK",slug:"a-comprehensive-modeling-and-simulation-of-power-quality-disturbances-using-matlab-simulink",totalDownloads:5943,totalCrossrefCites:2,totalDimensionsCites:4,book:{slug:"power-quality-issues-in-distributed-generation",title:"Power Quality Issues in Distributed Generation",fullTitle:"Power Quality Issues in Distributed Generation"},signatures:"Rodney H.G. Tan and Vigna K. Ramachandaramurthy",authors:[{id:"152137",title:"Dr.",name:"Vigna",middleName:null,surname:"Ramachandaramurthy",slug:"vigna-ramachandaramurthy",fullName:"Vigna Ramachandaramurthy"},{id:"175327",title:"Dr.",name:"Rodney",middleName:"H.G.",surname:"Tan",slug:"rodney-tan",fullName:"Rodney Tan"}]},{id:"49024",title:"Biological and Chemical Wastewater Treatment Processes",slug:"biological-and-chemical-wastewater-treatment-processes",totalDownloads:6623,totalCrossrefCites:1,totalDimensionsCites:2,book:{slug:"wastewater-treatment-engineering",title:"Wastewater Treatment Engineering",fullTitle:"Wastewater Treatment Engineering"},signatures:"Mohamed Samer",authors:[{id:"175050",title:"Associate Prof.",name:"Mohamed",middleName:null,surname:"Samer",slug:"mohamed-samer",fullName:"Mohamed Samer"}]},{id:"17504",title:"DFT Calculation for Adatom Adsorption on Graphene",slug:"dft-calculation-for-adatom-adsorption-on-graphene",totalDownloads:8754,totalCrossrefCites:10,totalDimensionsCites:30,book:{slug:"graphene-simulation",title:"Graphene Simulation",fullTitle:"Graphene Simulation"},signatures:"Kengo Nakada and Akira Ishii",authors:[{id:"39143",title:"Prof.",name:"Akira",middleName:null,surname:"Ishii",slug:"akira-ishii",fullName:"Akira Ishii"},{id:"39156",title:"Dr.",name:"Kengo",middleName:null,surname:"Nakada",slug:"kengo-nakada",fullName:"Kengo Nakada"}]},{id:"17021",title:"Microwave dielectric heating in modern organic synthesis and drug discovery",slug:"microwave-dielectric-heating-in-modern-organic-synthesis-and-drug-discovery",totalDownloads:7956,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"microwave-heating",title:"Microwave Heating",fullTitle:"Microwave Heating"},signatures:"Hong Liu and Lei Zhang",authors:[{id:"53628",title:"Prof.",name:"Hong",middleName:null,surname:"Liu",slug:"hong-liu",fullName:"Hong Liu"},{id:"56156",title:"Dr.",name:"Lei",middleName:null,surname:"Zhang",slug:"lei-zhang",fullName:"Lei Zhang"}]},{id:"48702",title:"Pressure Drop and Heat Transfer during a Two-phase Flow Vaporization of Propane in Horizontal Smooth Minichannels",slug:"pressure-drop-and-heat-transfer-during-a-two-phase-flow-vaporization-of-propane-in-horizontal-smooth",totalDownloads:4364,totalCrossrefCites:0,totalDimensionsCites:0,book:{slug:"heat-transfer-studies-and-applications",title:"Heat Transfer",fullTitle:"Heat Transfer Studies and Applications"},signatures:"Jong-Taek Oh, Kwang-Il Choi and Nguyen-Ba Chien",authors:[{id:"14439",title:"Prof.",name:"Jong-Taek",middleName:null,surname:"Oh",slug:"jong-taek-oh",fullName:"Jong-Taek Oh"}]},{id:"18374",title:"Gas Sensors for Monitoring Air Pollution",slug:"gas-sensors-for-monitoring-air-pollution",totalDownloads:6839,totalCrossrefCites:0,totalDimensionsCites:5,book:{slug:"monitoring-control-and-effects-of-air-pollution",title:"Monitoring, Control and Effects of Air Pollution",fullTitle:"Monitoring, Control and Effects of Air Pollution"},signatures:"Kwang Soo Yoo",authors:[{id:"36961",title:"Prof.",name:"Kwang Soo",middleName:null,surname:"Yoo",slug:"kwang-soo-yoo",fullName:"Kwang Soo Yoo"}]},{id:"497",title:"Artificial Bee Colony Algorithm and Its Application to Generalized Assignment Problem",slug:"artificial_bee_colony_algorithm_and_its_application_to_generalized_assignment_problem",totalDownloads:14060,totalCrossrefCites:38,totalDimensionsCites:127,book:{slug:"swarm_intelligence_focus_on_ant_and_particle_swarm_optimization",title:"Swarm Intelligence",fullTitle:"Swarm Intelligence, Focus on Ant and Particle Swarm Optimization"},signatures:"Adil Baykasoğlu, Lale Özbakır and Pınar Tapkan",authors:null}],onlineFirstChaptersFilter:{topicSlug:"physical-sciences-engineering-and-technology",limit:3,offset:0},onlineFirstChaptersCollection:[{id:"65794",title:"Thermal Analysis of an Absorption and Adsorption Cooling Chillers Using a Modulating Tempering Valve",slug:"thermal-analysis-of-an-absorption-and-adsorption-cooling-chillers-using-a-modulating-tempering-valve",totalDownloads:0,totalDimensionsCites:0,doi:"10.5772/intechopen.84737",book:{title:"Zero and Net Zero Energy"},signatures:"Jesús Cerezo Román, Rosenberg Javier Romero Domínguez, Antonio Rodríguez Martínez and Pedro Soto Parra"},{id:"65785",title:"Acoustics from Interior Designer Perspective",slug:"acoustics-from-interior-designer-perspective",totalDownloads:1,totalDimensionsCites:0,doi:"10.5772/intechopen.84167",book:{title:"Acoustics of Materials"},signatures:"Naglaa Sami AbdelAziz Mahmoud"},{id:"65799",title:"Hybrid Liquid-Crystal/Photonic-Crystal Devices: Current Research and Applications",slug:"hybrid-liquid-crystal-photonic-crystal-devices-current-research-and-applications",totalDownloads:0,totalDimensionsCites:0,doi:"10.5772/intechopen.82833",book:{title:"Photonic Crystals - A Glimpse of the Current Research Trends"},signatures:"Yu-Cheng Hsiao"}],onlineFirstChaptersTotal:677},preDownload:{success:null,errors:{}},privacyPolicy:{},sponsorshipBooks:{sponsorshipBooks:[],offset:0,limit:8,total:null},humansInSpaceProgram:{},route:{name:"generic.detail",path:"/page/content-alerts",hash:"",query:{},params:{page:"content-alerts"},fullPath:"/page/content-alerts",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)}()