A. Gnanaprakasam, V. Sivakumar, M. Thirumarimurugan
This paper aims to review the recent works on the photocatalytic degradation of organic pollutants in the presence of nanophotocatalyst. In this regard the effects of operation parameters which could influence the photocatalytic degradation of organic pollutants (such as catalyst preparation method, initial concentration of organic pollutants, presence of doping, catalyst loading, calcinations temperature, pH, presence of oxidants, UV intensity, temperature, and presence of supports) are discussed. Recent research suggests that the parameters mentioned above have great influence on the photocatalytic activity of prepared nanocatalyst. Also, the general mechanism of photocatalytic degradation and some recent synthesis methods are discussed here.
{"title":"Influencing Parameters in the Photocatalytic Degradation of Organic Effluent via Nanometal Oxide Catalyst: A Review","authors":"A. Gnanaprakasam, V. Sivakumar, M. Thirumarimurugan","doi":"10.1155/2015/601827","DOIUrl":"https://doi.org/10.1155/2015/601827","url":null,"abstract":"This paper aims to review the recent works on the photocatalytic degradation of organic pollutants in the presence of nanophotocatalyst. In this regard the effects of operation parameters which could influence the photocatalytic degradation of organic pollutants (such as catalyst preparation method, initial concentration of organic pollutants, presence of doping, catalyst loading, calcinations temperature, pH, presence of oxidants, UV intensity, temperature, and presence of supports) are discussed. Recent research suggests that the parameters mentioned above have great influence on the photocatalytic activity of prepared nanocatalyst. Also, the general mechanism of photocatalytic degradation and some recent synthesis methods are discussed here.","PeriodicalId":13278,"journal":{"name":"Indian Journal of Materials Science","volume":"4 1","pages":"1-16"},"PeriodicalIF":0.0,"publicationDate":"2015-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76139354","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}
Tool steels in metal forming industry are exposed to complex and aggressive conditions due to multiple effects (mechanical, thermal, or tribological loading) and require defined mechanical properties. Also machining of tool steel with poor machinability like AISI D6 to manufacture form tools is an extremely difficult task. This paper investigates the microstructural, mechanical, and machining behavior of AISI D6 steel in annealed and hardened conditions. Various mechanical tests indicated good hardenability, improved surface hardness, and phenomenal improvement in tensile strength but extremely poor resistance to impact in both annealed and hardened condition for this steel. The machining characteristics of AISI D6 steel were evaluated using a 2k unreplicated full factorial design approach and statistical techniques have been used to assess and identify the significant factors, namely, cutting speed, feed, depth of cut, and approach angle, in minimizing surface roughness and main cutting force while machining this steel with a carbide tool. It was found that the depth of cut, feed, and approach angle are the most significant factors affecting the surface roughness and depth of cut and feed affect the main cutting force. Cutting speed has no effect on surface roughness and main cutting force in machining of the steel in annealed condition.
{"title":"Mechanical Characterization and Machinability Behavior of Annealed AISI D6 Cold Working Steel","authors":"M. K. Nayak, R. Sehgal, R. Sharma","doi":"10.1155/2015/196178","DOIUrl":"https://doi.org/10.1155/2015/196178","url":null,"abstract":"Tool steels in metal forming industry are exposed to complex and aggressive conditions due to multiple effects (mechanical, thermal, or tribological loading) and require defined mechanical properties. Also machining of tool steel with poor machinability like AISI D6 to manufacture form tools is an extremely difficult task. This paper investigates the microstructural, mechanical, and machining behavior of AISI D6 steel in annealed and hardened conditions. Various mechanical tests indicated good hardenability, improved surface hardness, and phenomenal improvement in tensile strength but extremely poor resistance to impact in both annealed and hardened condition for this steel. The machining characteristics of AISI D6 steel were evaluated using a 2k unreplicated full factorial design approach and statistical techniques have been used to assess and identify the significant factors, namely, cutting speed, feed, depth of cut, and approach angle, in minimizing surface roughness and main cutting force while machining this steel with a carbide tool. It was found that the depth of cut, feed, and approach angle are the most significant factors affecting the surface roughness and depth of cut and feed affect the main cutting force. Cutting speed has no effect on surface roughness and main cutting force in machining of the steel in annealed condition.","PeriodicalId":13278,"journal":{"name":"Indian Journal of Materials Science","volume":"3 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2015-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74203642","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}
Siafu Ibahati Sempeho, H. Kim, E. Mubofu, A. Pogrebnoi, Godlisten N. Shao, A. Hilonga
Kaolinite-urea nanocomposites were prepared via intercalation reactions in an attempt to investigate the dynamic nature of kaolinite morphology for advanced applications in controlled release systems (CRS). Characterization was done using SEM-EDX, XRF, ATR-FTIR, XRD, and DT/DTG; Andreasen pipette sedimentation technique was used to determine the grain size distribution of the raw kaolinite. The X-ray diffraction pattern revealed the existence of an FCC Bravais lattice where the intercalation ratios attained were 51.2%, 32.4%, 7.0%, and 38.4% for hydroxyaluminum oligomeric intercalated kaolinite, substituted urea intercalated kaolinite, calcined DMSO intercalated kaolinite, and hydroxyaluminum reintercalated kaolinite, respectively, along with their respective crystallite sizes of 33.51–31.73 nm, 41.92–39.69 nm, 22.31–21.13 nm, and 41.86–39.63 nm. The outcomes demonstrated that the employed intercalation routes require improvements as the intercalation reactions were in average only ≈32.3%. The observations unveiled that it is possible to manipulate kaolinite structure into various morphologies including dense-tightly packed overlapping euhedral pseudo hexagonal platelets, stacked vermiform morphologies, postulated forms, and unique patterns exhibiting self-assembled curled glomeruli-like morphologies. Such a diversity of kaolinite morphologies expedites its advanced applications in the controlled release systems (CRS) such as drug delivery systems and controlled release fertilizers (CRFs).
{"title":"Dynamics of Kaolinite-Urea Nanocomposites via Coupled DMSO-Hydroxyaluminum Oligomeric Intermediates","authors":"Siafu Ibahati Sempeho, H. Kim, E. Mubofu, A. Pogrebnoi, Godlisten N. Shao, A. Hilonga","doi":"10.1155/2015/920835","DOIUrl":"https://doi.org/10.1155/2015/920835","url":null,"abstract":"Kaolinite-urea nanocomposites were prepared via intercalation reactions in an attempt to investigate the dynamic nature of kaolinite morphology for advanced applications in controlled release systems (CRS). Characterization was done using SEM-EDX, XRF, ATR-FTIR, XRD, and DT/DTG; Andreasen pipette sedimentation technique was used to determine the grain size distribution of the raw kaolinite. The X-ray diffraction pattern revealed the existence of an FCC Bravais lattice where the intercalation ratios attained were 51.2%, 32.4%, 7.0%, and 38.4% for hydroxyaluminum oligomeric intercalated kaolinite, substituted urea intercalated kaolinite, calcined DMSO intercalated kaolinite, and hydroxyaluminum reintercalated kaolinite, respectively, along with their respective crystallite sizes of 33.51–31.73 nm, 41.92–39.69 nm, 22.31–21.13 nm, and 41.86–39.63 nm. The outcomes demonstrated that the employed intercalation routes require improvements as the intercalation reactions were in average only ≈32.3%. The observations unveiled that it is possible to manipulate kaolinite structure into various morphologies including dense-tightly packed overlapping euhedral pseudo hexagonal platelets, stacked vermiform morphologies, postulated forms, and unique patterns exhibiting self-assembled curled glomeruli-like morphologies. Such a diversity of kaolinite morphologies expedites its advanced applications in the controlled release systems (CRS) such as drug delivery systems and controlled release fertilizers (CRFs).","PeriodicalId":13278,"journal":{"name":"Indian Journal of Materials Science","volume":"13 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2015-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79524686","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}
The objective of the present investigation was to explore the potential of Chitosan based polymeric matrices as carrier for sustained stomach specific delivery of model drug Propranolol Hydrochloride. Briefly, single unit hydrodynamically balanced (HBS) capsule formulations were prepared by encapsulating in hard gelatin capsules, intimately mixed physical mixtures of drug, and cationic low molecular weight Chitosan (LMCH) in combination with either anionic medium viscosity sodium alginate (MSA) or sodium carboxymethylcellulose (CMCNa). The effect of incorporation of nonionic polymers, namely, tamarind seed gum (TSG) and microcrystalline cellulose (MCCP), was also investigated. It was observed that HBS formulations remained buoyant for up to 6 h in 0.1 M HCl, when LMCH : anionic/nonionic polymer ratio was at least 4 : 1. It was also observed that LMCH has formed polyelectrolyte complex (PEC) with MSA (4 : 1.5 ratio) and CMCNa (4 : 1 ratio) in situ during the gelation of HBS formulations in 0.1 M HCl. The retardation in drug release was attributed to the PEC formation between LMCH and MSA/CMCNa. Incorporation of MCCP (rapid gel formation) and TSG (Plug formation) was found to be innovative. From the data, it is suggested that Chitosan based polymeric matrices may constitute an excellent carrier for stomach specific drug delivery.
本研究的目的是探讨壳聚糖基聚合物基质作为模型药物盐酸心得安持续胃特异性递送载体的潜力。简单地说，单单元水动力平衡(HBS)胶囊配方是通过在硬明胶胶囊中包封药物、阳离子低分子量壳聚糖(LMCH)与阴离子中等粘度海藻酸钠(MSA)或羧甲基纤维素钠(CMCNa)紧密混合的物理混合物制备的。研究了罗望子籽胶(TSG)和微晶纤维素(MCCP)等非离子型聚合物的掺入效果。当LMCH:阴离子/非离子聚合物的比例至少为4:1时，HBS配方在0.1 M HCl中保持浮力长达6 h。研究还发现，在0.1 M HCl溶液中，LMCH与MSA(4:1 .5)和CMCNa(4:1)在原位形成了多电解质复合物(PEC)。LMCH与MSA/CMCNa之间形成PEC，导致药物释放延迟。MCCP(快速凝胶形成)和TSG(堵塞形成)的结合被认为是创新的。由此可见，壳聚糖基聚合物基质可能是胃特异性给药的优良载体。
{"title":"Evaluation of Chitosan Based Polymeric Matrices for Sustained Stomach Specific Delivery of Propranolol Hydrochloride","authors":"Juhi Dubey, A. Verma, N. Verma","doi":"10.1155/2015/312934","DOIUrl":"https://doi.org/10.1155/2015/312934","url":null,"abstract":"The objective of the present investigation was to explore the potential of Chitosan based polymeric matrices as carrier for sustained stomach specific delivery of model drug Propranolol Hydrochloride. Briefly, single unit hydrodynamically balanced (HBS) capsule formulations were prepared by encapsulating in hard gelatin capsules, intimately mixed physical mixtures of drug, and cationic low molecular weight Chitosan (LMCH) in combination with either anionic medium viscosity sodium alginate (MSA) or sodium carboxymethylcellulose (CMCNa). The effect of incorporation of nonionic polymers, namely, tamarind seed gum (TSG) and microcrystalline cellulose (MCCP), was also investigated. It was observed that HBS formulations remained buoyant for up to 6 h in 0.1 M HCl, when LMCH : anionic/nonionic polymer ratio was at least 4 : 1. It was also observed that LMCH has formed polyelectrolyte complex (PEC) with MSA (4 : 1.5 ratio) and CMCNa (4 : 1 ratio) in situ during the gelation of HBS formulations in 0.1 M HCl. The retardation in drug release was attributed to the PEC formation between LMCH and MSA/CMCNa. Incorporation of MCCP (rapid gel formation) and TSG (Plug formation) was found to be innovative. From the data, it is suggested that Chitosan based polymeric matrices may constitute an excellent carrier for stomach specific drug delivery.","PeriodicalId":13278,"journal":{"name":"Indian Journal of Materials Science","volume":"44 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2015-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72649085","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}
This paper explains the sliding wear performance of red mud, fly ash, and carbon composite coating on mild steel. The complex mixture of red mud, fly ash, and carbon is plasma sprayed at 9 kW operating power level. The coatings are examined to study the coating morphology, XRD phase transformation, wear rate, and wear morphology. Wear rate (in terms of cumulative mass loss) with sliding time has been demonstrated in the study. At first pure red mud is plasma coated to observe the coating characteristics and then compounded with 20% carbon, 30% carbon, and 20% carbon
{"title":"Effect of Fly Ash and Carbon Reinforcement on Dry Sliding Wear Behaviour of Red Mud","authors":"H. Sutar, Debashis Roy, S. Mishra","doi":"10.1155/2015/296324","DOIUrl":"https://doi.org/10.1155/2015/296324","url":null,"abstract":"This paper explains the sliding wear performance of red mud, fly ash, and carbon composite coating on mild steel. The complex mixture of red mud, fly ash, and carbon is plasma sprayed at 9 kW operating power level. The coatings are examined to study the coating morphology, XRD phase transformation, wear rate, and wear morphology. Wear rate (in terms of cumulative mass loss) with sliding time has been demonstrated in the study. At first pure red mud is plasma coated to observe the coating characteristics and then compounded with 20% carbon, 30% carbon, and 20% carbon","PeriodicalId":13278,"journal":{"name":"Indian Journal of Materials Science","volume":"31 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2015-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73000210","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}
Noble metal nanomaterials have attracted mounting research attention for applications in diverse fields of catalysis, biology, and nanotechnology. In the present study, we have undertaken a detailed investigation on synthesis, characterization, and catalytic activity studies for CO oxidation by nanogold catalysts supported over CeO2 and CeO2-ZrO2 (1 : 1 mole ratio). The support systems were prepared by modified, simple precipitation technique and the Au supported samples were synthesized using deposition-precipitation with urea method. The physicochemical characterization was performed by XRD, ICP-AES, BET surface area, FT-IR, UV-Vis DRS, Raman Spectroscopy, TEM, and XPS techniques. Au/CeO2 catalyst showed more than 80% CO conversions at 30°C, whereas Au/CeO2-ZrO2 exhibited ~100% CO conversion at that temperature. The catalytic performance of Au catalysts is highly dependent on the nature of the support.
{"title":"Enhanced Catalytic Activity of Supported Gold Catalysts for Oxidation of Noxious Environmental Pollutant CO","authors":"P. Saikia, A. T. Miah, B. Malakar, A. Bordoloi","doi":"10.1155/2015/658346","DOIUrl":"https://doi.org/10.1155/2015/658346","url":null,"abstract":"Noble metal nanomaterials have attracted mounting research attention for applications in diverse fields of catalysis, biology, and nanotechnology. In the present study, we have undertaken a detailed investigation on synthesis, characterization, and catalytic activity studies for CO oxidation by nanogold catalysts supported over CeO2 and CeO2-ZrO2 (1 : 1 mole ratio). The support systems were prepared by modified, simple precipitation technique and the Au supported samples were synthesized using deposition-precipitation with urea method. The physicochemical characterization was performed by XRD, ICP-AES, BET surface area, FT-IR, UV-Vis DRS, Raman Spectroscopy, TEM, and XPS techniques. Au/CeO2 catalyst showed more than 80% CO conversions at 30°C, whereas Au/CeO2-ZrO2 exhibited ~100% CO conversion at that temperature. The catalytic performance of Au catalysts is highly dependent on the nature of the support.","PeriodicalId":13278,"journal":{"name":"Indian Journal of Materials Science","volume":"93 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2015-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83845910","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}
Devender Singh, Vijeta Tanwar, Shri Bhagwan, Vandna Nishal, Suman Sheoran, Sonika Kadyan, A. Samantilleke, P. S. Kadyan
Trivalent europium doped yttriate nanophosphors were synthesized by rapid facile gel combustion technique. The photoluminescence (PL) properties of these Eu3
采用快速易凝胶燃烧技术合成了三价铕掺杂钇酸盐纳米荧光粉。这些Eu3的光致发光(PL)性质
{"title":"Synthesis and Optical Characterization of Europium Doped MY2O4 (M = Mg, Ca, and Sr) Nanophosphors for Solid State Lightening Applications","authors":"Devender Singh, Vijeta Tanwar, Shri Bhagwan, Vandna Nishal, Suman Sheoran, Sonika Kadyan, A. Samantilleke, P. S. Kadyan","doi":"10.1155/2015/845065","DOIUrl":"https://doi.org/10.1155/2015/845065","url":null,"abstract":"Trivalent europium doped yttriate nanophosphors were synthesized by rapid facile gel combustion technique. The photoluminescence (PL) properties of these Eu3","PeriodicalId":13278,"journal":{"name":"Indian Journal of Materials Science","volume":"2 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2015-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75298275","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}
This investigation analyzes the performance of a magnetic fluid based squeeze film for a sphere in a rough spherical seat with slip velocity. The slip model of Beavers and Joseph has been deployed to study the effect of velocity slip while the stochastic model of Christensen and Tonder has been used to calculate the effect of surface roughness. The concerned statistically averaged Reynolds’ type equation is solved to derive the pressure distribution which results in the calculation of load carrying capacity. The results presented in graphical forms confirm that the adverse effect of slip velocity can be overcome to a large extent at least in the case of negatively skewed roughness. However, lower values of slip may be preferred for enhancing the performance characteristics of the bearing system. Besides, variance (−ve) provides a little support to improve the performance characteristics.
研究了一种基于磁流体的挤压膜在具有滑移速度的粗糙球座中的性能。采用Beavers and Joseph的滑移模型来研究速度滑移的影响，采用Christensen and Tonder的随机模型来计算表面粗糙度的影响。求解相关的统计平均雷诺型方程，导出压力分布，从而计算承载能力。以图形形式给出的结果证实，滑移速度的不利影响可以在很大程度上克服，至少在负偏斜粗糙度的情况下。然而，为了提高轴承系统的性能特性，较低的滑移值可能是首选的。此外，方差(- ve)为改进性能特性提供了一点支持。
{"title":"Combined Effect of Slip Velocity and Surface Roughness on a Magnetic Squeeze Film for a Sphere in a Spherical Seat","authors":"G. Deheri, Sejal J. Patel","doi":"10.1155/2015/159698","DOIUrl":"https://doi.org/10.1155/2015/159698","url":null,"abstract":"This investigation analyzes the performance of a magnetic fluid based squeeze film for a sphere in a rough spherical seat with slip velocity. The slip model of Beavers and Joseph has been deployed to study the effect of velocity slip while the stochastic model of Christensen and Tonder has been used to calculate the effect of surface roughness. The concerned statistically averaged Reynolds’ type equation is solved to derive the pressure distribution which results in the calculation of load carrying capacity. The results presented in graphical forms confirm that the adverse effect of slip velocity can be overcome to a large extent at least in the case of negatively skewed roughness. However, lower values of slip may be preferred for enhancing the performance characteristics of the bearing system. Besides, variance (−ve) provides a little support to improve the performance characteristics.","PeriodicalId":13278,"journal":{"name":"Indian Journal of Materials Science","volume":"135 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2015-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89294463","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}
In understanding the effect of K+ substitution by M2+ (M = Ca, Sr, and Ba) on crystallization and microstructural properties of boroaluminosilicate glass system, the SiO2-MgO-Al2O3-B2O3-MgF2-K2O-Li2O-AlPO4 glasses were prepared by single-step melt-quenching at 1500°C. Density of base glass (2.64 g·cm−3) is found to be decreased in presence of CaO and SrO. is increased by 5–10°C and decreased by 13–20°C on addition of M2+. The variation of , and decrease of thermal expansion (CTE) from 7.55 to 6.67–6.97 (×10−6/K, at 50–500°C) in substituting K+ by M2+ are attributed to the higher field-strength of Ca2+, Sr2+, and Ba2+. Opaque mica glass-ceramics were derived from the transparent boroaluminosilicate glasses by controlled heat treatment at 1050°C (duration = 4 h); and the predominant crystalline phase was identified as fluorophlogopite (KMg3AlSi3O10F2) by XRD and FTIR study. Glass-ceramic microstructure reveals that the platelike mica flake crystals predominate in presence of K2O and CaO but restructured to smaller droplet like spherical shaped mica on addition of SrO and BaO. Wide range of CTE values (9.54–13.38 × 10−6/K at 50–800°C) are obtained for such glass-ceramics. Having higher CTE value after crystallization, the CaO containing SiO2-MgO-Al2O3-B2O3-MgF2-K2O-Li2O-AlPO4 glass can be useful as SOFC sealing material.
{"title":"Effects of M2+ (M = Ca, Sr, and Ba) Addition on Crystallization and Microstructure of SiO2-MgO-Al2O3-B2O3-K2O-F Glass","authors":"Mrinmoy Garai, N. Sasmal, B. Karmakar","doi":"10.1155/2015/638341","DOIUrl":"https://doi.org/10.1155/2015/638341","url":null,"abstract":"In understanding the effect of K+ substitution by M2+ (M = Ca, Sr, and Ba) on crystallization and microstructural properties of boroaluminosilicate glass system, the SiO2-MgO-Al2O3-B2O3-MgF2-K2O-Li2O-AlPO4 glasses were prepared by single-step melt-quenching at 1500°C. Density of base glass (2.64 g·cm−3) is found to be decreased in presence of CaO and SrO. is increased by 5–10°C and decreased by 13–20°C on addition of M2+. The variation of , and decrease of thermal expansion (CTE) from 7.55 to 6.67–6.97 (×10−6/K, at 50–500°C) in substituting K+ by M2+ are attributed to the higher field-strength of Ca2+, Sr2+, and Ba2+. Opaque mica glass-ceramics were derived from the transparent boroaluminosilicate glasses by controlled heat treatment at 1050°C (duration = 4 h); and the predominant crystalline phase was identified as fluorophlogopite (KMg3AlSi3O10F2) by XRD and FTIR study. Glass-ceramic microstructure reveals that the platelike mica flake crystals predominate in presence of K2O and CaO but restructured to smaller droplet like spherical shaped mica on addition of SrO and BaO. Wide range of CTE values (9.54–13.38 × 10−6/K at 50–800°C) are obtained for such glass-ceramics. Having higher CTE value after crystallization, the CaO containing SiO2-MgO-Al2O3-B2O3-MgF2-K2O-Li2O-AlPO4 glass can be useful as SOFC sealing material.","PeriodicalId":13278,"journal":{"name":"Indian Journal of Materials Science","volume":"8 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2015-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86755441","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}
The electronic properties of magnetic cubic AuCu3 type GdX3 (X = In, Sn, Tl, and Pb) have been studied using first principles calculations based on density functional theory. Because of the presence of strong on-site Coulomb repulsion between the highly localized 4f electrons of Gd atoms, we have used LSDA
利用基于密度泛函理论的第一性原理计算，研究了磁性立方AuCu3型GdX3 (X = In, Sn, Tl，和Pb)的电子性质。由于Gd原子高度定域的4f电子之间存在强烈的库仑斥力，我们使用了LSDA
{"title":"Electronic Structure, Electronic Charge Density, and Optical Properties Analysis of GdX3 (X = In, Sn, Tl, and Pb) Compounds: DFT Calculations","authors":"J. A. Abraham, G. Pagare, S. Sanyal","doi":"10.1155/2015/296095","DOIUrl":"https://doi.org/10.1155/2015/296095","url":null,"abstract":"The electronic properties of magnetic cubic AuCu3 type GdX3 (X = In, Sn, Tl, and Pb) have been studied using first principles calculations based on density functional theory. Because of the presence of strong on-site Coulomb repulsion between the highly localized 4f electrons of Gd atoms, we have used LSDA","PeriodicalId":13278,"journal":{"name":"Indian Journal of Materials Science","volume":"78 1","pages":"1-11"},"PeriodicalIF":0.0,"publicationDate":"2015-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80057389","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}
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