Pub Date : 2019-01-01DOI: 10.15406/mseij.2019.03.00088
Ilias Tourlomousiss
The fracture behavior in sandwich composite structures has been directed toward the understanding of crack propagation, and at the same time toward improving the durability of composites against fracture [1-4]. A crack flaw may be introduced during processing or subsequent service conditions. It may result from low velocity impact, from eccentricities in the structural load path, or from discontinuities in structures, which induce a significant out-of-plane stress. Generally for a state of plane stress the stresses normal to the plane of interest are negligibly small. On the other hand plane strain is assumed to occur where the strains to the normal plane are negligibly small. In our study both these cases will be studied. The sandwich beam considered is shown in Figure 1. Material properties and geometrical data are shown in Tables 1 & Tables 2 respectively. Additional information regarding material properties as shear and tensile strength, are given in Table 3. In this study combining the elastoplastic concepts approach with the step by step crack propagation inside the core of a sandwich beam very close to the upper skin interface, a numerical solution is proposed via the finite element analysis.1‒4 An initial crack length is assumed. Methods of evaluating the plastic zone under mixed mode loading conditions and small scale yielding ARE presented. In the presence of plastic zone at the crack tip the stiffness of the component decreases and the compliance increases. To incorporate the effect of plasticity in Fracture analysis the crack is mathematically modeled to be longer than the actual length. In the finite element model this is incorporated by taking into account the radius of singular elements around the crack tip. This radius is at the same order of magnitude with the crack tip plastic zone confronted in our analysis. The relations which relate the fracture parameters and the radius of the plastic as well as the direction of the propagation zone under the three point bending are presented. The extension of the plastic zone along the crack axis is succeeded by finding the point at which one of the yield criteria is satisfied. It is quite difficult to give a proper description of plastic zone shape and size. In all the models to simplify the analysis the material is assumed to be elastic-perfectly plastic. In this study considering that the plastic zones are created around the tips of the cracks under small scale yielding, the stress fields are determined in terms of the stress intensity factors using the asymptotic solutions.
{"title":"A finite element analysis of fractured sandwich composite structures under small scale yielding","authors":"Ilias Tourlomousiss","doi":"10.15406/mseij.2019.03.00088","DOIUrl":"https://doi.org/10.15406/mseij.2019.03.00088","url":null,"abstract":"The fracture behavior in sandwich composite structures has been directed toward the understanding of crack propagation, and at the same time toward improving the durability of composites against fracture [1-4]. A crack flaw may be introduced during processing or subsequent service conditions. It may result from low velocity impact, from eccentricities in the structural load path, or from discontinuities in structures, which induce a significant out-of-plane stress. Generally for a state of plane stress the stresses normal to the plane of interest are negligibly small. On the other hand plane strain is assumed to occur where the strains to the normal plane are negligibly small. In our study both these cases will be studied. The sandwich beam considered is shown in Figure 1. Material properties and geometrical data are shown in Tables 1 & Tables 2 respectively. Additional information regarding material properties as shear and tensile strength, are given in Table 3. In this study combining the elastoplastic concepts approach with the step by step crack propagation inside the core of a sandwich beam very close to the upper skin interface, a numerical solution is proposed via the finite element analysis.1‒4 An initial crack length is assumed. Methods of evaluating the plastic zone under mixed mode loading conditions and small scale yielding ARE presented. In the presence of plastic zone at the crack tip the stiffness of the component decreases and the compliance increases. To incorporate the effect of plasticity in Fracture analysis the crack is mathematically modeled to be longer than the actual length. In the finite element model this is incorporated by taking into account the radius of singular elements around the crack tip. This radius is at the same order of magnitude with the crack tip plastic zone confronted in our analysis. The relations which relate the fracture parameters and the radius of the plastic as well as the direction of the propagation zone under the three point bending are presented. The extension of the plastic zone along the crack axis is succeeded by finding the point at which one of the yield criteria is satisfied. It is quite difficult to give a proper description of plastic zone shape and size. In all the models to simplify the analysis the material is assumed to be elastic-perfectly plastic. In this study considering that the plastic zones are created around the tips of the cracks under small scale yielding, the stress fields are determined in terms of the stress intensity factors using the asymptotic solutions.","PeriodicalId":18241,"journal":{"name":"Material Science & Engineering International Journal","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80485301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.15406/mseij.2019.03.00098
Gunel Huseynova
Different electronic devices based on organic semiconductors (OSCs) are being developed and promoted every year due to unique and outstanding properties of the organic materials including flexibility, transparency, light weight, and solution-process ability. However, these materials are not fully commercialized due to their intrinsically low electrical performance and poor stability. And in order to overcome these issues several approaches have been developed and one of them is doping. Doping is the most straightforward method to increase electrical conductivity of the materials in the first place. The organic light-emitting diode (OLED) industry already uses this method to finally commercialize these organic devices successfully.1 It should be noted that doping of OSCs is completely different from that of inorganic ones in which conductivity is enhanced via the increase of charge carriers provided by the impurity atoms that replace the atoms in the host lattice. In organic electronics, no replacement of host lattice atoms by impurity atoms occurs. Rather, it is just simple and direct introduction of extra charge carriers to the whole host molecule via a charge transfer process.2 In this case, the effectiveness of the doping process depends on the energy level differences between the materials’ highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). This requirement seriously limits the doping possibilities of the organic materials as dopant and host molecules with matching energy levels are rare. One of the suggested alternatives for doping of OSCs in which the energy levels of the two materials can be ignored, is application of Lewis acids and bases for pand n-type doping, respectively.3‒7 In this work, two cationic organic dyes, Pyronin B (PyB) and Acridine Orange (AO), are investigated as p-type dopants for a conjugated ambipolar polymer diketopyrrolopyrrole-thieno [3,2-b]thiophene (DPPT-TT). The dopants are conjugated molecules with Lewis acid nature.
{"title":"Solution-processed electrical doping of organic semiconductors and their application for organic devices","authors":"Gunel Huseynova","doi":"10.15406/mseij.2019.03.00098","DOIUrl":"https://doi.org/10.15406/mseij.2019.03.00098","url":null,"abstract":"Different electronic devices based on organic semiconductors (OSCs) are being developed and promoted every year due to unique and outstanding properties of the organic materials including flexibility, transparency, light weight, and solution-process ability. However, these materials are not fully commercialized due to their intrinsically low electrical performance and poor stability. And in order to overcome these issues several approaches have been developed and one of them is doping. Doping is the most straightforward method to increase electrical conductivity of the materials in the first place. The organic light-emitting diode (OLED) industry already uses this method to finally commercialize these organic devices successfully.1 It should be noted that doping of OSCs is completely different from that of inorganic ones in which conductivity is enhanced via the increase of charge carriers provided by the impurity atoms that replace the atoms in the host lattice. In organic electronics, no replacement of host lattice atoms by impurity atoms occurs. Rather, it is just simple and direct introduction of extra charge carriers to the whole host molecule via a charge transfer process.2 In this case, the effectiveness of the doping process depends on the energy level differences between the materials’ highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). This requirement seriously limits the doping possibilities of the organic materials as dopant and host molecules with matching energy levels are rare. One of the suggested alternatives for doping of OSCs in which the energy levels of the two materials can be ignored, is application of Lewis acids and bases for pand n-type doping, respectively.3‒7 In this work, two cationic organic dyes, Pyronin B (PyB) and Acridine Orange (AO), are investigated as p-type dopants for a conjugated ambipolar polymer diketopyrrolopyrrole-thieno [3,2-b]thiophene (DPPT-TT). The dopants are conjugated molecules with Lewis acid nature.","PeriodicalId":18241,"journal":{"name":"Material Science & Engineering International Journal","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77670371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.15406/mseij.2019.03.00095
Iwamoto Gy
The discovery of nonferrous magnetic alloys was reported by Heusler1 in 1898 and since then the investigation and application of these alloys on industrial and scientific devices have been growing continuously. Guillaud2 described a variable Curie Temperature (between 90°C and 314°C) for MnSb alloy, obtained exclusively through the variation of the stoichiometry (from 45% to 49% in atomic percentage of Sb (at.%Sb). At least six different phase diagrams were published, besides the long time from its discovery, they still have some uncertain regions related to minimum/maximum stoichiometry of MnSb phase and its respective Tc. Okamoto’s phase diagram3 defines this region being from 45% and 49% atomic Sb at room temperature up to 314°C, and respective Tc varying from 90°C to 314°C. Crystallographic files from ICSD4 provide references where the phase is described as Mn1.092Sb or Mn1.1Sb. Eight samples, from 43% to 50% at. Sb was produced, covering the complete range of Mn1.092Sb phase. Guillaud 2 reported a tunable magnetic transition through stoichiometry between 90°C to 314°C, Teramoto & Van Run5 confirmed the non dependency of annealing temperature between 400°C and 700°C for 49% atomic of Sb, and plotted a partial phase diagram (Figure 1), where MnSb stable phase varies with temperature from 46 to 50%at of Sb at 400°C, and a single point at 41% atomic Sb (%at.Sb) at 840°C describing a non linear behavior. Teramoto & Van Run5 reported quenching from temperatures between 400°C to 700°C didn’t change the Tc, being independent of annealing or quenching temperature, but only related to stoichiometry. Okamoto3 reported a peritectic transition at 840°C and variable Tc related stoichiometry from 44% to 49% at.Sb. at 400°C. Chen6 identified the peritectic temperature at 843°C and the stoichiometry between 45% and 49.5% atomic of Sb at 400°C, Vanyarkho7 r e p o r t e d the peritectic temperature at 841°C and the MnSb phase from 45% to 49% at 400°C, Williams8 reported the peritectic temperature at 853°C and variable magnetic range from 40% to 50% below 573; and Kainzbauer9 reported the peritectic temperature at 830°C and limits of MnSb phase from 45.5% to 50.5at% of Sb. Although Guillaud2 described the reaction at MnSb alloy as a SOMT (Second Order Magnetic Transition), Nwodo10 reported a FOMT (first order magnetic transition), AFM-FI (Antiferromagnetic→Ferrimagnetic) reaction, attributed to a spin reorientation of Mn2Sb dropped with Sn (Mn2Sb0.9Sn0.1).
{"title":"Study of MnSb alloy on the range of 43% to 50% of at.%Sb, revealed an unexpected presence of MN2SB phase","authors":"Iwamoto Gy","doi":"10.15406/mseij.2019.03.00095","DOIUrl":"https://doi.org/10.15406/mseij.2019.03.00095","url":null,"abstract":"The discovery of nonferrous magnetic alloys was reported by Heusler1 in 1898 and since then the investigation and application of these alloys on industrial and scientific devices have been growing continuously. Guillaud2 described a variable Curie Temperature (between 90°C and 314°C) for MnSb alloy, obtained exclusively through the variation of the stoichiometry (from 45% to 49% in atomic percentage of Sb (at.%Sb). At least six different phase diagrams were published, besides the long time from its discovery, they still have some uncertain regions related to minimum/maximum stoichiometry of MnSb phase and its respective Tc. Okamoto’s phase diagram3 defines this region being from 45% and 49% atomic Sb at room temperature up to 314°C, and respective Tc varying from 90°C to 314°C. Crystallographic files from ICSD4 provide references where the phase is described as Mn1.092Sb or Mn1.1Sb. Eight samples, from 43% to 50% at. Sb was produced, covering the complete range of Mn1.092Sb phase. Guillaud 2 reported a tunable magnetic transition through stoichiometry between 90°C to 314°C, Teramoto & Van Run5 confirmed the non dependency of annealing temperature between 400°C and 700°C for 49% atomic of Sb, and plotted a partial phase diagram (Figure 1), where MnSb stable phase varies with temperature from 46 to 50%at of Sb at 400°C, and a single point at 41% atomic Sb (%at.Sb) at 840°C describing a non linear behavior. Teramoto & Van Run5 reported quenching from temperatures between 400°C to 700°C didn’t change the Tc, being independent of annealing or quenching temperature, but only related to stoichiometry. Okamoto3 reported a peritectic transition at 840°C and variable Tc related stoichiometry from 44% to 49% at.Sb. at 400°C. Chen6 identified the peritectic temperature at 843°C and the stoichiometry between 45% and 49.5% atomic of Sb at 400°C, Vanyarkho7 r e p o r t e d the peritectic temperature at 841°C and the MnSb phase from 45% to 49% at 400°C, Williams8 reported the peritectic temperature at 853°C and variable magnetic range from 40% to 50% below 573; and Kainzbauer9 reported the peritectic temperature at 830°C and limits of MnSb phase from 45.5% to 50.5at% of Sb. Although Guillaud2 described the reaction at MnSb alloy as a SOMT (Second Order Magnetic Transition), Nwodo10 reported a FOMT (first order magnetic transition), AFM-FI (Antiferromagnetic→Ferrimagnetic) reaction, attributed to a spin reorientation of Mn2Sb dropped with Sn (Mn2Sb0.9Sn0.1).","PeriodicalId":18241,"journal":{"name":"Material Science & Engineering International Journal","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86816976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.15406/mseij.2019.03.00103
O. Olaniran, O. Uwaifo, E. Bamidele, Bolanle A. Olaniran
The availability of diverse materials has posed a big challenge of materials selection for different engineering applications.1 However; this has enhanced the preference for affordable high performance materials with requisite quality. Metal Matrix Composites (MMCs) has emerged as a viable alternative to different conventional materials.2 The application of these composites have been established in different industries such aerospace, marine, defense and automobile. Metals such as copper, aluminium, magnesium and their alloys are the most commonly used MMCs due to their light weights. The unique properties of these metals are combined with different kind of reinforcement materials to produce composite materials of distinct properties.3‒6 Aluminium based composites has continually generated a lot of interest judging from the available volume of literature. The versatility of its application, lower cost of production and its outstanding properties have distinguished Al based composites and it has remained the most used MMC.2 The reinforcement materials selected with Al MMC is very crucial in harnessing the desired property. In different research, numerous reinforcement materials such as fly ash, silicon carbide, alumina, silica, graphite, mica among others have been selected with Aluminium MMCs.7 However, the areas of application of Al based composites is expected to continue growing. Therefore, different combinations of important reinforcement materials particularly agro waste products including bamboo leaf ash and rice husk require further study.
{"title":"An investigation of the mechanical properties of organic silica, bamboo leaf ash and rice husk reinforced aluminium hybrid composite","authors":"O. Olaniran, O. Uwaifo, E. Bamidele, Bolanle A. Olaniran","doi":"10.15406/mseij.2019.03.00103","DOIUrl":"https://doi.org/10.15406/mseij.2019.03.00103","url":null,"abstract":"The availability of diverse materials has posed a big challenge of materials selection for different engineering applications.1 However; this has enhanced the preference for affordable high performance materials with requisite quality. Metal Matrix Composites (MMCs) has emerged as a viable alternative to different conventional materials.2 The application of these composites have been established in different industries such aerospace, marine, defense and automobile. Metals such as copper, aluminium, magnesium and their alloys are the most commonly used MMCs due to their light weights. The unique properties of these metals are combined with different kind of reinforcement materials to produce composite materials of distinct properties.3‒6 Aluminium based composites has continually generated a lot of interest judging from the available volume of literature. The versatility of its application, lower cost of production and its outstanding properties have distinguished Al based composites and it has remained the most used MMC.2 The reinforcement materials selected with Al MMC is very crucial in harnessing the desired property. In different research, numerous reinforcement materials such as fly ash, silicon carbide, alumina, silica, graphite, mica among others have been selected with Aluminium MMCs.7 However, the areas of application of Al based composites is expected to continue growing. Therefore, different combinations of important reinforcement materials particularly agro waste products including bamboo leaf ash and rice husk require further study.","PeriodicalId":18241,"journal":{"name":"Material Science & Engineering International Journal","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89487413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.15406/mseij.2019.03.00116
A. Grozdanov, G. Gentile, M. Avella, T. Dobreva, R. Kotsilkova
Design and development of new types of polymer based nanocomposites (NC) is rapidly emerging as a multidisciplinary research activity whose results could broaden the applications of polymers to the great benefit of many different industries: automotive, construction, aerospace, electrical and electronics, food packaging.1‒4 Polymers, resins and plastics containing additives such as clays and various nanostructures have recently become widely used as replacements for conventional materials of steel and other metal products, or their coatings, especially in the field of automotive industry. The application of the polymer NC coatings for the corrosion protection of steels was reviewed by Toshiaki Ohtsuka5 he reported various systems mainly based on conductive polymer matrix. The incorporation of layered silicates into polymer matrix was a research focus for many years, since the results of the Toyota research team showed that the incorporation of 2 vol% of exfoliated clay into Naylon-6 contributes to about 90oC increase in glass transition temperature and double Young’s modulus.4 Traditionally, alkyd resins as oil-modified polyesters, have been placed amongst the most widely used resins in exterior solvent-based inexpensive coating applications because of their high gloss and durability. Alkyd-based nanocomposite coatings were reported to exhibit better properties compared to the traditional ones.2 It was shown that water vapour permeability of nanocomposite coatings remarkably decreased with respect to neat coating. For example, a decrease of water vapour permeability by a factor of 15 has been measured.1 Inorganic–organic composites based on organo-alkoxysilanes and other alkoxides have demonstrated their usefulness even for hard coatings on eye-glass lenses.6 It has been shown that the addition of nanoparticles, especially in combination with epoxy silanes, which act as an inorganic as well as an organic crosslinking agent, leads to a substantial increase of the abrasion resistance of such systems without losing any transparency. Therefore, due to the incorporation of nanoparticles into the certain polymer matrix, high abrasion resistance can be obtained.1,5 Avella et al.7 have shown that the presence of only 2% nanoparticles strongly improves the abrasion resistance, as well as the wear of Poly(Methyl methacrylate) (PMMA). 6 The nanocomposites showed an average weight loss about half (2,5% against 5% of removal material) with respect to that of neat polymer.
{"title":"Nanocomposite coatings based on alkyd resin with TiO2 and SiO2 nanoparticles","authors":"A. Grozdanov, G. Gentile, M. Avella, T. Dobreva, R. Kotsilkova","doi":"10.15406/mseij.2019.03.00116","DOIUrl":"https://doi.org/10.15406/mseij.2019.03.00116","url":null,"abstract":"Design and development of new types of polymer based nanocomposites (NC) is rapidly emerging as a multidisciplinary research activity whose results could broaden the applications of polymers to the great benefit of many different industries: automotive, construction, aerospace, electrical and electronics, food packaging.1‒4 Polymers, resins and plastics containing additives such as clays and various nanostructures have recently become widely used as replacements for conventional materials of steel and other metal products, or their coatings, especially in the field of automotive industry. The application of the polymer NC coatings for the corrosion protection of steels was reviewed by Toshiaki Ohtsuka5 he reported various systems mainly based on conductive polymer matrix. The incorporation of layered silicates into polymer matrix was a research focus for many years, since the results of the Toyota research team showed that the incorporation of 2 vol% of exfoliated clay into Naylon-6 contributes to about 90oC increase in glass transition temperature and double Young’s modulus.4 Traditionally, alkyd resins as oil-modified polyesters, have been placed amongst the most widely used resins in exterior solvent-based inexpensive coating applications because of their high gloss and durability. Alkyd-based nanocomposite coatings were reported to exhibit better properties compared to the traditional ones.2 It was shown that water vapour permeability of nanocomposite coatings remarkably decreased with respect to neat coating. For example, a decrease of water vapour permeability by a factor of 15 has been measured.1 Inorganic–organic composites based on organo-alkoxysilanes and other alkoxides have demonstrated their usefulness even for hard coatings on eye-glass lenses.6 It has been shown that the addition of nanoparticles, especially in combination with epoxy silanes, which act as an inorganic as well as an organic crosslinking agent, leads to a substantial increase of the abrasion resistance of such systems without losing any transparency. Therefore, due to the incorporation of nanoparticles into the certain polymer matrix, high abrasion resistance can be obtained.1,5 Avella et al.7 have shown that the presence of only 2% nanoparticles strongly improves the abrasion resistance, as well as the wear of Poly(Methyl methacrylate) (PMMA). 6 The nanocomposites showed an average weight loss about half (2,5% against 5% of removal material) with respect to that of neat polymer.","PeriodicalId":18241,"journal":{"name":"Material Science & Engineering International Journal","volume":"7 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81406473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.15406/mseij.2019.03.00089
G. Huseynov
Organic semiconductors (OSCs) are the potential key materials for future flexible electronics due to their outstanding mechanical and optoelectronic properties1,2 Electronic devices such as organic light emitting diodes have already shown successful progress for flat panel displays, and application of OSCs is gradually expanding to various fields of electronics.1–3 However, OSCs still lag behind inorganic ones due to their poor electrical properties including low charge carrier mobility and conductivity as well as device stability issues.4–7 In order to overcome these issues, several approaches have been developed one of which is doping.5 Doping is one of the most effective methods to improve electrical properties of OSCs through increasing their charge carrier density and mobility.2,8–11 However, the doping of OSCs is different from the doping of inorganic ones. Unlike the latter, doping in organic electronics does not assume the replacement of a host lattice atom by an impurity atom. It is rather a simple charge transfer between two molecules.2,8,9,12–14 A significant number of research groups have reported different kinds of dopants for OSCs. In this review, a summary of the dopants, namely cationic species that can be applied as both pand n-type dopants, is introduced. Cationic dyes as dopants for organic molecules
{"title":"Cationic species as dopants for organic semiconductors","authors":"G. Huseynov","doi":"10.15406/mseij.2019.03.00089","DOIUrl":"https://doi.org/10.15406/mseij.2019.03.00089","url":null,"abstract":"Organic semiconductors (OSCs) are the potential key materials for future flexible electronics due to their outstanding mechanical and optoelectronic properties1,2 Electronic devices such as organic light emitting diodes have already shown successful progress for flat panel displays, and application of OSCs is gradually expanding to various fields of electronics.1–3 However, OSCs still lag behind inorganic ones due to their poor electrical properties including low charge carrier mobility and conductivity as well as device stability issues.4–7 In order to overcome these issues, several approaches have been developed one of which is doping.5 Doping is one of the most effective methods to improve electrical properties of OSCs through increasing their charge carrier density and mobility.2,8–11 However, the doping of OSCs is different from the doping of inorganic ones. Unlike the latter, doping in organic electronics does not assume the replacement of a host lattice atom by an impurity atom. It is rather a simple charge transfer between two molecules.2,8,9,12–14 A significant number of research groups have reported different kinds of dopants for OSCs. In this review, a summary of the dopants, namely cationic species that can be applied as both pand n-type dopants, is introduced. Cationic dyes as dopants for organic molecules","PeriodicalId":18241,"journal":{"name":"Material Science & Engineering International Journal","volume":"110 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80545799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.15406/mseij.2019.03.00106
Gunel Huseynova
The development of organic semiconducting materials paved a path for developing a range of organic devices such as organic field effect transistors (OFETs), organic light – emitting diodes (OLEDs), organic photovoltaics (OPVs)1 and so on. There are a lot of advantages of these organic semiconducting materials and devices made based on them over their inorganic counterparts such as unique physical and mechanical properties which in its turn opens opportunities for flexible, light – weight, printable and even paperbased devices.2–5 Organic materials are also very easily processed. They offer fabrication methods ranging from conventional thermal evaporation to solution – processing that enables simple fabrication steps such as spin – coating,6 drop – casting,7 inkjet – printing8 and etc. at temperatures as low as room temperature. Also, organic materials are plenty and hundreds of them are synthesized every year. They offer a great range of options for synthesizers. But the main advantage of these organic materials and devices is that they themselves and the processes they go through are not as expensive and complicated as those of their inorganic counterparts. But organic semiconductors suffer from very serious problems such as very poor electrical properties and stability. Although organic semiconductors offer a great range of application fields, these two issues make them fall behind the inorganic semiconductors.
{"title":"Molecular chemical doping for improvement of performance in organic field effect transistors","authors":"Gunel Huseynova","doi":"10.15406/mseij.2019.03.00106","DOIUrl":"https://doi.org/10.15406/mseij.2019.03.00106","url":null,"abstract":"The development of organic semiconducting materials paved a path for developing a range of organic devices such as organic field effect transistors (OFETs), organic light – emitting diodes (OLEDs), organic photovoltaics (OPVs)1 and so on. There are a lot of advantages of these organic semiconducting materials and devices made based on them over their inorganic counterparts such as unique physical and mechanical properties which in its turn opens opportunities for flexible, light – weight, printable and even paperbased devices.2–5 Organic materials are also very easily processed. They offer fabrication methods ranging from conventional thermal evaporation to solution – processing that enables simple fabrication steps such as spin – coating,6 drop – casting,7 inkjet – printing8 and etc. at temperatures as low as room temperature. Also, organic materials are plenty and hundreds of them are synthesized every year. They offer a great range of options for synthesizers. But the main advantage of these organic materials and devices is that they themselves and the processes they go through are not as expensive and complicated as those of their inorganic counterparts. But organic semiconductors suffer from very serious problems such as very poor electrical properties and stability. Although organic semiconductors offer a great range of application fields, these two issues make them fall behind the inorganic semiconductors.","PeriodicalId":18241,"journal":{"name":"Material Science & Engineering International Journal","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80478859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.15406/mseij.2019.03.00086
Jinwu Kang
Phase diagrams describing phases under varying composition, temperature and pressure are considered as the road maps for metals and alloys, minerals and ceramics. They are usually of very complicated spatial geometry, hard for understanding. Wireframe phase diagram models have been always used in teaching and scientific research since 1950’s.1 As information technology appeared, computer aided drawing of phase diagrams came to be popular.2–9 Some commercial phase diagram software were developed, such as Panda T, Thermo calc, Fact Sage, etc. However, the display of 3D phase diagram on monitor or paper is actually a faked 3D stereo display. They are 3D shapes, but they can be only watched as 2D images, 3D effects are realized by perspective view, or by rotation and slicing of the models. It is hard to tell the special relationships of curves, surfaces and solid regions of the three dimensional phase diagrams printed in books. Tamas and Pal realized 3D stereo effect of phase diagrams by anaglyph method as early as 1970.10 But, all the figures were the combinations of only red and cyan lines and curves by hand drawing. Thus, it was impossible to realize plane shading, transparency effect, color pictures and movies. Kang et al. managed to improve the illustration of complex phase diagrams, such as wireframe phase diagrams, computer aided models and introduced 3D stereo visualization into phase diagram and modeling and simulation and published an album about simulated results of castings in which the stereo effect can be achieved by the aid of red-cyan glasses.11–13 In this paper, with the adoption of 3D stereoscopic visualization technology, significant 3D stereo effect of a typical complex phase diagram was realized.
{"title":"3D Stereo spatial phase diagram for a typical complex ternary system","authors":"Jinwu Kang","doi":"10.15406/mseij.2019.03.00086","DOIUrl":"https://doi.org/10.15406/mseij.2019.03.00086","url":null,"abstract":"Phase diagrams describing phases under varying composition, temperature and pressure are considered as the road maps for metals and alloys, minerals and ceramics. They are usually of very complicated spatial geometry, hard for understanding. Wireframe phase diagram models have been always used in teaching and scientific research since 1950’s.1 As information technology appeared, computer aided drawing of phase diagrams came to be popular.2–9 Some commercial phase diagram software were developed, such as Panda T, Thermo calc, Fact Sage, etc. However, the display of 3D phase diagram on monitor or paper is actually a faked 3D stereo display. They are 3D shapes, but they can be only watched as 2D images, 3D effects are realized by perspective view, or by rotation and slicing of the models. It is hard to tell the special relationships of curves, surfaces and solid regions of the three dimensional phase diagrams printed in books. Tamas and Pal realized 3D stereo effect of phase diagrams by anaglyph method as early as 1970.10 But, all the figures were the combinations of only red and cyan lines and curves by hand drawing. Thus, it was impossible to realize plane shading, transparency effect, color pictures and movies. Kang et al. managed to improve the illustration of complex phase diagrams, such as wireframe phase diagrams, computer aided models and introduced 3D stereo visualization into phase diagram and modeling and simulation and published an album about simulated results of castings in which the stereo effect can be achieved by the aid of red-cyan glasses.11–13 In this paper, with the adoption of 3D stereoscopic visualization technology, significant 3D stereo effect of a typical complex phase diagram was realized.","PeriodicalId":18241,"journal":{"name":"Material Science & Engineering International Journal","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90615659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.15406/mseij.2019.03.00091
B. C., Deferrari N
{"title":"Study of hot-workability of titanium alloys through hot-torsion testing and its application to the optimization of forging and extrusion processes","authors":"B. C., Deferrari N","doi":"10.15406/mseij.2019.03.00091","DOIUrl":"https://doi.org/10.15406/mseij.2019.03.00091","url":null,"abstract":"","PeriodicalId":18241,"journal":{"name":"Material Science & Engineering International Journal","volume":"189 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75418472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.15406/MSEIJ.2019.03.00079
Jinwu Kang
research and review articles were published in volume 2 in 2018. Ghann & Uddin1 investigated the synthesis and characterization of CdSeS/ZnS quantum–dot–gold nanoparticles hybrids (denoted as QD–GNP) , which is a composite structure of semiconductor nanomaterial and metal nanoparticles. Its wavelength of maximum absorption is different from the gold nanoparticles and the quantum dot. And strong photoluminescence quenching was observed in this hybrid. The interaction of this hybrid with terahertz radiation shows the unique terahertz signal of the un conjugated gold nanoparticles and quantum dots versus the conjugated forms. The results indicate that the hybrid gold nanoparticle and quantum dot will have great potential for other optical application. Abraham et al.,2 prepared multiwalled carbon nanotube based styrene butadiene rubber nanocomposites. Imdazolium type ionic liquid was found to facilitate the dispersion of MWCNT in polymer matrix and to act as accelerators for the sulphur vulcanisation of SBR composites and to be helpful for the formation of three dimensional network of MWCNT in rubber matrix. Phul et al.,3 reported a synthesis method of copper nanoparticles by wet chemical reduction using L–ascorbic acid as reducing agent. The as–synthesized nanoparticles have cubic structure with an average particle size of 3 nm, with10times higher surface area as compared to the literature. The fabricated Cu nanoparticles showed noteworthy enhancement in the degradation of Rhodamine B organic dye when used as catalyst for its degradation under both dark and light conditions.
{"title":"Nano materials are at the frontier of research","authors":"Jinwu Kang","doi":"10.15406/MSEIJ.2019.03.00079","DOIUrl":"https://doi.org/10.15406/MSEIJ.2019.03.00079","url":null,"abstract":"research and review articles were published in volume 2 in 2018. Ghann & Uddin1 investigated the synthesis and characterization of CdSeS/ZnS quantum–dot–gold nanoparticles hybrids (denoted as QD–GNP) , which is a composite structure of semiconductor nanomaterial and metal nanoparticles. Its wavelength of maximum absorption is different from the gold nanoparticles and the quantum dot. And strong photoluminescence quenching was observed in this hybrid. The interaction of this hybrid with terahertz radiation shows the unique terahertz signal of the un conjugated gold nanoparticles and quantum dots versus the conjugated forms. The results indicate that the hybrid gold nanoparticle and quantum dot will have great potential for other optical application. Abraham et al.,2 prepared multiwalled carbon nanotube based styrene butadiene rubber nanocomposites. Imdazolium type ionic liquid was found to facilitate the dispersion of MWCNT in polymer matrix and to act as accelerators for the sulphur vulcanisation of SBR composites and to be helpful for the formation of three dimensional network of MWCNT in rubber matrix. Phul et al.,3 reported a synthesis method of copper nanoparticles by wet chemical reduction using L–ascorbic acid as reducing agent. The as–synthesized nanoparticles have cubic structure with an average particle size of 3 nm, with10times higher surface area as compared to the literature. The fabricated Cu nanoparticles showed noteworthy enhancement in the degradation of Rhodamine B organic dye when used as catalyst for its degradation under both dark and light conditions.","PeriodicalId":18241,"journal":{"name":"Material Science & Engineering International Journal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86840543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：