Pub Date : 2019-11-04DOI: 10.11648/J.IJMSA.20190806.12
Semih Taskaya, B. Zengin, Kursat Kaymaz, M. Aşkin
The basic logic in the finite element method is to simplify and solve a complex problem. In this method, the solution region is divided into a plurality of simple, small, connected, sub-regions called finite elements. In other words, the problem which is divided into parts connected by a plurality of joint points can be easily solved. St 37 and St 70 steels are materials used in the manufacturing of general building materials, produced by processing the hot-formed steel further through a cold drawing process. Ansys; is a computer aided engineering program where analysis and simulations can be performed in computer aided engineering studies. It enables effective studies in different disciplines such as mechanics, structural analysis, computational fluid dynamics and heat transfer. The finite element method, which enables the solution of complex engineering problems with controllable parts by simplifying, is a common and useful solution method used in many engineering applications. St and St 70 steels are modeled as three-dimensional I-beams 3 mm in thickness in Ansys program package in accordance with the finite element method. Finite element method helps simplifying complex engineering problems and solving them with controllable parts. Elastic stress analyses were performed in X, Y, Z axes by stabilizing the right and left supports of steel beams and applying a pressure of 100 MPa on the top flanges. It was observed in Ansys simulation analyses that elastic stress effect was higher in St 37 steel compared to St 70 steel.
{"title":"Elastic Stress Analysis of St 37 and St 70 Steels with Finite Element Method","authors":"Semih Taskaya, B. Zengin, Kursat Kaymaz, M. Aşkin","doi":"10.11648/J.IJMSA.20190806.12","DOIUrl":"https://doi.org/10.11648/J.IJMSA.20190806.12","url":null,"abstract":"The basic logic in the finite element method is to simplify and solve a complex problem. In this method, the solution region is divided into a plurality of simple, small, connected, sub-regions called finite elements. In other words, the problem which is divided into parts connected by a plurality of joint points can be easily solved. St 37 and St 70 steels are materials used in the manufacturing of general building materials, produced by processing the hot-formed steel further through a cold drawing process. Ansys; is a computer aided engineering program where analysis and simulations can be performed in computer aided engineering studies. It enables effective studies in different disciplines such as mechanics, structural analysis, computational fluid dynamics and heat transfer. The finite element method, which enables the solution of complex engineering problems with controllable parts by simplifying, is a common and useful solution method used in many engineering applications. St and St 70 steels are modeled as three-dimensional I-beams 3 mm in thickness in Ansys program package in accordance with the finite element method. Finite element method helps simplifying complex engineering problems and solving them with controllable parts. Elastic stress analyses were performed in X, Y, Z axes by stabilizing the right and left supports of steel beams and applying a pressure of 100 MPa on the top flanges. It was observed in Ansys simulation analyses that elastic stress effect was higher in St 37 steel compared to St 70 steel.","PeriodicalId":14116,"journal":{"name":"International Journal of Materials Science and Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76542611","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 : 2019-11-01DOI: 10.11648/J.IJMSA.20190806.11
Toshiro Okawa, I. Clark, K. Tashiro, H. Honma, K. Yoshihara, O. Takai
It becomes important to measure mechanical properties of local area of materials because of downsizing of industrial materials, and the fracture of materials often starts at the nanoscale defects. Therefore, the measurement of hardness of the local area of materials is one of key technologies to develop new materials. Nanoindentation is the depth sensing indentation method and can measure the mechanical properties of nanoscale area of materials. The hardness of materials under the controlled environment like high temperature is a big issue in energy or environment industries. Therefore, it becomes important to measure high temperature mechanical properties of nanoscale area of materials by nanoindentation. However, the shape of indenter may change when an indenter contacts to the material surface at high temperatures, and the nanoindentation at high temperatures may lead to inaccuracy of measurements. Nanoindentation does not measure indented are directly but converts the indentation depth to the indented area by area function. In order to correctly convert the indentation depth to the indented area, it is necessary to derive the area function of indented area at high temperatures. In this report, the area function is proposed that considers the change of indenter shape during repeating contact at heated materials. By using this proposed area function, nanoindentation hardness and the reduced modulus of sapphire were obtained at 303K, 473K, 673K, 873K and 1073K successfully. The nanoindentation can be used at high temperatures, if this proposed area function is used.
{"title":"Area Function for Nanoindentation at High Temperatures","authors":"Toshiro Okawa, I. Clark, K. Tashiro, H. Honma, K. Yoshihara, O. Takai","doi":"10.11648/J.IJMSA.20190806.11","DOIUrl":"https://doi.org/10.11648/J.IJMSA.20190806.11","url":null,"abstract":"It becomes important to measure mechanical properties of local area of materials because of downsizing of industrial materials, and the fracture of materials often starts at the nanoscale defects. Therefore, the measurement of hardness of the local area of materials is one of key technologies to develop new materials. Nanoindentation is the depth sensing indentation method and can measure the mechanical properties of nanoscale area of materials. The hardness of materials under the controlled environment like high temperature is a big issue in energy or environment industries. Therefore, it becomes important to measure high temperature mechanical properties of nanoscale area of materials by nanoindentation. However, the shape of indenter may change when an indenter contacts to the material surface at high temperatures, and the nanoindentation at high temperatures may lead to inaccuracy of measurements. Nanoindentation does not measure indented are directly but converts the indentation depth to the indented area by area function. In order to correctly convert the indentation depth to the indented area, it is necessary to derive the area function of indented area at high temperatures. In this report, the area function is proposed that considers the change of indenter shape during repeating contact at heated materials. By using this proposed area function, nanoindentation hardness and the reduced modulus of sapphire were obtained at 303K, 473K, 673K, 873K and 1073K successfully. The nanoindentation can be used at high temperatures, if this proposed area function is used.","PeriodicalId":14116,"journal":{"name":"International Journal of Materials Science and Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82065127","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 : 2019-10-24DOI: 10.11648/j.ijmsa.20190805.12
Sechin Chang, B. Condon, Jade Smith, Sunghyun Nam
Flame retardant behaviour was imparted using the layer-by layer assemblies of phosphorus rich casein milk protein with eco-friendly inorganic chemicals on cotton fabrics. The cotton twill fabrics were prepared using two solutions; a mixture of positively charged branched polyethylenimine (BPEI) with urea and diammonium phosphate (DAP), and negatively charged casein. Layer-by-layer assemblies for flame retardant properties were applied using the pad-dry-cure method, and each coating formula was rotated for 20 bi-layers. The effectiveness to resist flame spread on treated fabrics was evaluated using vertical (ASTM D6413-08) and 45° angle flammability test (ASTM D1230-01) methods. In most case, char lengths of fabrics that passed the vertical flammability tests were less than 50% of the original length, and after-flame and after-glow times were less than one second. Thermal properties were tested the extent of char produced by untreated and treated fabrics at 600°C by thermogravimetric analysis (TGA). Micro-scale combustion calorimeter (MCC) and Limiting oxygen indices (LOI, ASTM D2863-09) were also assessed. All untreated fabrics showed LOI values of about 21% oxygen in nitrogen. LOI values for the treated casein with BPEI/urea/DAP fabrics were greater than 29-34% between 5.80-9.59 add on wt%. Their structural characterizations were revealed by TGA/FT-IR and SEM methods. The treated fabrics exhibited improved thermal stability, as evidenced by increased ignition times and lower heat release rates. The results of this study show that flame retardant nanocoatings can be readily applied to textile fabrics using a continuous process that is ideal for commercial and industrial applications.
{"title":"Innovative Approach to Flame Retardant Cotton Fabrics with Phosphorus Rich Casein via Layer-by-Layer Processing","authors":"Sechin Chang, B. Condon, Jade Smith, Sunghyun Nam","doi":"10.11648/j.ijmsa.20190805.12","DOIUrl":"https://doi.org/10.11648/j.ijmsa.20190805.12","url":null,"abstract":"Flame retardant behaviour was imparted using the layer-by layer assemblies of phosphorus rich casein milk protein with eco-friendly inorganic chemicals on cotton fabrics. The cotton twill fabrics were prepared using two solutions; a mixture of positively charged branched polyethylenimine (BPEI) with urea and diammonium phosphate (DAP), and negatively charged casein. Layer-by-layer assemblies for flame retardant properties were applied using the pad-dry-cure method, and each coating formula was rotated for 20 bi-layers. The effectiveness to resist flame spread on treated fabrics was evaluated using vertical (ASTM D6413-08) and 45° angle flammability test (ASTM D1230-01) methods. In most case, char lengths of fabrics that passed the vertical flammability tests were less than 50% of the original length, and after-flame and after-glow times were less than one second. Thermal properties were tested the extent of char produced by untreated and treated fabrics at 600°C by thermogravimetric analysis (TGA). Micro-scale combustion calorimeter (MCC) and Limiting oxygen indices (LOI, ASTM D2863-09) were also assessed. All untreated fabrics showed LOI values of about 21% oxygen in nitrogen. LOI values for the treated casein with BPEI/urea/DAP fabrics were greater than 29-34% between 5.80-9.59 add on wt%. Their structural characterizations were revealed by TGA/FT-IR and SEM methods. The treated fabrics exhibited improved thermal stability, as evidenced by increased ignition times and lower heat release rates. The results of this study show that flame retardant nanocoatings can be readily applied to textile fabrics using a continuous process that is ideal for commercial and industrial applications.","PeriodicalId":14116,"journal":{"name":"International Journal of Materials Science and Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79362062","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 : 2019-10-23DOI: 10.11648/j.ijmsa.20190805.13
N. Kimtangar, Djidengar Lazare, Deudjonbe Baruc, B. Tibi, Nzié Wolfgang
The palmyra is a wood particularly famous for its resistance to xylophages and various bad weather. But the determining factors of this resistance are unknown. This base material is available in the form of lignocellulosic waste generated in large quantities, following its grooming, maintenance and felling. This lignocellulosic waste is not valued in Chad. Its petiole is the biovegetal material widely used in Chad for the artisanal manufacture of furniture and other works. The present study concerns the determination of its physical, chemical and mechanical characteristics. We used chemical analyzes, physical tests and mechanical tests in three-point flexion, intension and in compression. Its contents in cellulose, lignin and Hemicellulose obtained justify its resistance to physical and chemical degradation and its attack by termites. The values of its mechanical characteristics obtained place it between the category D50 and D60 of hardwoods. Those of its physical properties place it among the light woods. This study, the first on the knowledge of the scientific and technical properties of the palmyra of Chad, opens perspectives on a new field of study on the behaviour of this abundant natural raw material with a view to its valorisation and its rational use in various fields, such as pulp and building construction and public works.
{"title":"Characterization of the Palmyra Petiole as a Biovegetal Material of Artisanal Construction in Chad","authors":"N. Kimtangar, Djidengar Lazare, Deudjonbe Baruc, B. Tibi, Nzié Wolfgang","doi":"10.11648/j.ijmsa.20190805.13","DOIUrl":"https://doi.org/10.11648/j.ijmsa.20190805.13","url":null,"abstract":"The palmyra is a wood particularly famous for its resistance to xylophages and various bad weather. But the determining factors of this resistance are unknown. This base material is available in the form of lignocellulosic waste generated in large quantities, following its grooming, maintenance and felling. This lignocellulosic waste is not valued in Chad. Its petiole is the biovegetal material widely used in Chad for the artisanal manufacture of furniture and other works. The present study concerns the determination of its physical, chemical and mechanical characteristics. We used chemical analyzes, physical tests and mechanical tests in three-point flexion, intension and in compression. Its contents in cellulose, lignin and Hemicellulose obtained justify its resistance to physical and chemical degradation and its attack by termites. The values of its mechanical characteristics obtained place it between the category D50 and D60 of hardwoods. Those of its physical properties place it among the light woods. This study, the first on the knowledge of the scientific and technical properties of the palmyra of Chad, opens perspectives on a new field of study on the behaviour of this abundant natural raw material with a view to its valorisation and its rational use in various fields, such as pulp and building construction and public works.","PeriodicalId":14116,"journal":{"name":"International Journal of Materials Science and Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82750379","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 : 2019-10-11DOI: 10.11648/j.ijmsa.20190805.11
Toshiro Okawa, I. Clark, K. Tashiro, H. Honma, K. Yoshihara, O. Takai
Nowadays, industrial products are downsized, and the structure of materials is controlled with the nanometer precision, and it becomes very important to measure the mechanical properties of local area of bulk material. Especially the hardness and the elastic modulus are important mechanical properties. The orientation dependence of hardness and reduced modulus of single crystal sapphire surface was investigated by nanoindentation. The conventional technique to measure the hardness of materials using an optical micrometer cannot evaluate mechanical properties of a local region of several µm or less. However, nanoindentation can measure mechanical properties of very small surface area of materials, and is expected to detect the micro structure dependence of mechanical properties. Nanoindentation uses very small indenter made of diamond, and measures the indentation depth. The measured depth is converted to the indented area size using the area function. The area function of the indenter can be obtained using a standard material (fused quartz) in advance. Therefore nanoindentation can measure the indented area size without using an optical micrometer. In this report, it was shown that the nanoindentation could detect the structure dependence of mechanical properties of materials. The specimen was a single crystal sapphire with c - axis surface, and the indenter was Berkovich type diamond tip. It was confirmed that the nanoindentation hardness was the lowest, and the reduced modulus was the largest, when the ridge line of indenter was oriented to the m - axis of single crystal. The nanoindentation could detect the structure dependence of a local area of mechanical properties materials.
{"title":"Orientation Dependence of Hardness and Reduced Modulus of Single Crystal Sapphire Surface Measured by Nanoindentation","authors":"Toshiro Okawa, I. Clark, K. Tashiro, H. Honma, K. Yoshihara, O. Takai","doi":"10.11648/j.ijmsa.20190805.11","DOIUrl":"https://doi.org/10.11648/j.ijmsa.20190805.11","url":null,"abstract":"Nowadays, industrial products are downsized, and the structure of materials is controlled with the nanometer precision, and it becomes very important to measure the mechanical properties of local area of bulk material. Especially the hardness and the elastic modulus are important mechanical properties. The orientation dependence of hardness and reduced modulus of single crystal sapphire surface was investigated by nanoindentation. The conventional technique to measure the hardness of materials using an optical micrometer cannot evaluate mechanical properties of a local region of several µm or less. However, nanoindentation can measure mechanical properties of very small surface area of materials, and is expected to detect the micro structure dependence of mechanical properties. Nanoindentation uses very small indenter made of diamond, and measures the indentation depth. The measured depth is converted to the indented area size using the area function. The area function of the indenter can be obtained using a standard material (fused quartz) in advance. Therefore nanoindentation can measure the indented area size without using an optical micrometer. In this report, it was shown that the nanoindentation could detect the structure dependence of mechanical properties of materials. The specimen was a single crystal sapphire with c - axis surface, and the indenter was Berkovich type diamond tip. It was confirmed that the nanoindentation hardness was the lowest, and the reduced modulus was the largest, when the ridge line of indenter was oriented to the m - axis of single crystal. The nanoindentation could detect the structure dependence of a local area of mechanical properties materials.","PeriodicalId":14116,"journal":{"name":"International Journal of Materials Science and Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84637445","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 : 2019-09-06DOI: 10.11648/J.IJMSA.20190804.11
O. Ngom, M. Faye, M. Mbaye, C. Mbow, B. Ba
In this article, a detailed study of the physical phenomena in the base of a silicon heterojunction solar cell (HIT) is elaborated. To carry out this work we have established a mathematical model which is in the form of a system of two continuity equations. The latter are subjected to physical conditions of nature to define our field of study. This system of continuity equations is solved using a computational program in a digital programming language. Numerical analysis is used in this study because the mathematical system describing the transport phenomena of load carriers (electrons and excitons) in a silicon heterojunction photovoltaic cell is very complex. Thus, to facilitate numerical resolution, the dimensional parameters of the physical system are rendered dimensionless. The resulting dimensionless equations are discretized by the finite volume method. They are then implemented in a calculation program by an iterative line-by-line relaxation method of the Gauss-Siedel type. In addition, with a low density coupling coefficient b=10-16cm3s-1 that depends on the material’s properties, the influence of temperature on the diffusion lengths, on the carrier and photocurrent densities, and on the internal quantum yield is studied. This study is carried out using polychromatic illumination with ultraviolet, visible and infrared wavelengths.
{"title":"Numerical Study of the Effect of Temperature on the Performance of a Silicon Heterojunction Solar Cell (HIT) in the Presence of Excitons","authors":"O. Ngom, M. Faye, M. Mbaye, C. Mbow, B. Ba","doi":"10.11648/J.IJMSA.20190804.11","DOIUrl":"https://doi.org/10.11648/J.IJMSA.20190804.11","url":null,"abstract":"In this article, a detailed study of the physical phenomena in the base of a silicon heterojunction solar cell (HIT) is elaborated. To carry out this work we have established a mathematical model which is in the form of a system of two continuity equations. The latter are subjected to physical conditions of nature to define our field of study. This system of continuity equations is solved using a computational program in a digital programming language. Numerical analysis is used in this study because the mathematical system describing the transport phenomena of load carriers (electrons and excitons) in a silicon heterojunction photovoltaic cell is very complex. Thus, to facilitate numerical resolution, the dimensional parameters of the physical system are rendered dimensionless. The resulting dimensionless equations are discretized by the finite volume method. They are then implemented in a calculation program by an iterative line-by-line relaxation method of the Gauss-Siedel type. In addition, with a low density coupling coefficient b=10-16cm3s-1 that depends on the material’s properties, the influence of temperature on the diffusion lengths, on the carrier and photocurrent densities, and on the internal quantum yield is studied. This study is carried out using polychromatic illumination with ultraviolet, visible and infrared wavelengths.","PeriodicalId":14116,"journal":{"name":"International Journal of Materials Science and Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75327361","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 : 2019-08-27DOI: 10.11648/J.IJMSA.20190803.13
Xingyu Zhang, B. Hanes, D. Brooks, S. Niezgoda
The main purpose of this research is to determine the effect of brazing treatment on mechanical properties of both titanium Grade 2 and titanium Grade 5 alloys. The research group obtained Grade 2 and Grade 5 titanium alloys and brazing- treated them at temperatures of 680, 800, 850, 900, 920, 950, and 1000°C. Afterward, each sample was tensile tested, mounted, hardness tested, and observed by optical microscope to investigate corresponding microstructures. Based on the result sheets, it was revealed that the yield strength and tensile strength and ultimate strength of Ti Grade 2 alloys showed drastic fall after heating to 680°C, then no change up to 850°C, fall again up to 950°C, and remained unchanged strength to 1000°C However, the Ti Grade 5 samples showed completely different behavior. The yield strength was unchanged after heating to different temperatures. When heating to 680°C. It didn’t affect the strength at all, then after heating to 800°C, the strength decreased about 100MPa. But after this, higher temperatures didn’t change strength anymore. The Ultimate strength however showed a different trend as it continuously went down at elevated temperature. Meanwhile, the hardness of both alloys decreased constantly when temperature increased. Regarding Ti Grade 2 alloys, the initial drop in strength was due to annealing. Around 800°C, alpha laths started to form and that caused strength to increase. When the temperature reached at 850°C, the basketweave alpha laths were formed. Over that temperature, the grain sizes were significantly large which caused the strength to decrease. However, there was not much of change in alpha/beta ratio for Ti Grade 5 alloys. EBSD could be a helpful method since the alpha grain size can be determined from that.
{"title":"Microstructure and Strength of Titanium After Heat Treatment at Different Temperatures in the Range of 680-1000°C","authors":"Xingyu Zhang, B. Hanes, D. Brooks, S. Niezgoda","doi":"10.11648/J.IJMSA.20190803.13","DOIUrl":"https://doi.org/10.11648/J.IJMSA.20190803.13","url":null,"abstract":"The main purpose of this research is to determine the effect of brazing treatment on mechanical properties of both titanium Grade 2 and titanium Grade 5 alloys. The research group obtained Grade 2 and Grade 5 titanium alloys and brazing- treated them at temperatures of 680, 800, 850, 900, 920, 950, and 1000°C. Afterward, each sample was tensile tested, mounted, hardness tested, and observed by optical microscope to investigate corresponding microstructures. Based on the result sheets, it was revealed that the yield strength and tensile strength and ultimate strength of Ti Grade 2 alloys showed drastic fall after heating to 680°C, then no change up to 850°C, fall again up to 950°C, and remained unchanged strength to 1000°C However, the Ti Grade 5 samples showed completely different behavior. The yield strength was unchanged after heating to different temperatures. When heating to 680°C. It didn’t affect the strength at all, then after heating to 800°C, the strength decreased about 100MPa. But after this, higher temperatures didn’t change strength anymore. The Ultimate strength however showed a different trend as it continuously went down at elevated temperature. Meanwhile, the hardness of both alloys decreased constantly when temperature increased. Regarding Ti Grade 2 alloys, the initial drop in strength was due to annealing. Around 800°C, alpha laths started to form and that caused strength to increase. When the temperature reached at 850°C, the basketweave alpha laths were formed. Over that temperature, the grain sizes were significantly large which caused the strength to decrease. However, there was not much of change in alpha/beta ratio for Ti Grade 5 alloys. EBSD could be a helpful method since the alpha grain size can be determined from that.","PeriodicalId":14116,"journal":{"name":"International Journal of Materials Science and Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88589057","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 : 2019-08-23DOI: 10.11648/J.IJMSA.20190803.12
Jomana Alsenan, L. Chou
This study was designed to investigate the effect of inorganic phosphate (Pi) at different concentrations on odontogenesis of the normal human dental pulp cells (hDPCs). Normal human dental pulp cells derived from extracted pristine teeth were cultured in growth medium with supplements of inorganic phosphate (Pi) in 0 ppm, 2 ppm, 4 ppm, 5 ppm and 8 ppm, for the time intervals of 16 hours, 7, 14, and 21 days. Cell proliferation rates were measured by the optical density of crystal violet dye stained cells. ALP activity was measured by fluorometric assay. Expression of Dentin Sialoprotein (DSP) was measured by ELISA. The data were presented as the mean of triplicates. Statistical analysis was conducted using JMP Pro 12 (ver. 12.1.0) in one-way ANOVA and Tukey HSD post-hoc tests. Cell attachment efficiency was reduced significantly by additional Pi of 2, 4 and 5 ppm (P<0.05). At 21 days, cultures with 2, 4 and 5 ppm supplemental Pi displayed significantly higher cell proliferation rates compared to the control group at day 14 (P<0.05) and at day 21 (P<0.05). At day 7, cultures with 2, 4, 5 and 8 ppm supplemental Pi yield significantly higher levels of ALP activity (P<0.05) compared to the control group. At day 7, cultures with 5 ppm Pi supplement showed significantly higher levels of DSP expression (P<0.05) compared to the control group and the rest of the other groups. Supplemental Pi in concentration of 5 ppm could significantly induce proliferation and odontogenesis of hDPCs. This is the first report to demonstrate Pi-induced odontogenesis, leading to potential development and clinical application of future Pi containing dental pulp capping or root canal filling materials.
{"title":"Inorganic Phosphate Effect of on Human Dental Pulp Cell Cultures","authors":"Jomana Alsenan, L. Chou","doi":"10.11648/J.IJMSA.20190803.12","DOIUrl":"https://doi.org/10.11648/J.IJMSA.20190803.12","url":null,"abstract":"This study was designed to investigate the effect of inorganic phosphate (Pi) at different concentrations on odontogenesis of the normal human dental pulp cells (hDPCs). Normal human dental pulp cells derived from extracted pristine teeth were cultured in growth medium with supplements of inorganic phosphate (Pi) in 0 ppm, 2 ppm, 4 ppm, 5 ppm and 8 ppm, for the time intervals of 16 hours, 7, 14, and 21 days. Cell proliferation rates were measured by the optical density of crystal violet dye stained cells. ALP activity was measured by fluorometric assay. Expression of Dentin Sialoprotein (DSP) was measured by ELISA. The data were presented as the mean of triplicates. Statistical analysis was conducted using JMP Pro 12 (ver. 12.1.0) in one-way ANOVA and Tukey HSD post-hoc tests. Cell attachment efficiency was reduced significantly by additional Pi of 2, 4 and 5 ppm (P<0.05). At 21 days, cultures with 2, 4 and 5 ppm supplemental Pi displayed significantly higher cell proliferation rates compared to the control group at day 14 (P<0.05) and at day 21 (P<0.05). At day 7, cultures with 2, 4, 5 and 8 ppm supplemental Pi yield significantly higher levels of ALP activity (P<0.05) compared to the control group. At day 7, cultures with 5 ppm Pi supplement showed significantly higher levels of DSP expression (P<0.05) compared to the control group and the rest of the other groups. Supplemental Pi in concentration of 5 ppm could significantly induce proliferation and odontogenesis of hDPCs. This is the first report to demonstrate Pi-induced odontogenesis, leading to potential development and clinical application of future Pi containing dental pulp capping or root canal filling materials.","PeriodicalId":14116,"journal":{"name":"International Journal of Materials Science and Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80409167","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 : 2019-07-30DOI: 10.11648/J.IJMSA.20190803.11
Fang Xu, Yulong Liao, Huaiwu Zhang
LiZnTi ferrite ceramics with high saturation flux density (Bs), large remanence ratio (Br/Bs) and high saturation magnetization (4πMs) is a vital material for high frequency devices. In the present work, we prepared uniform and compact LiZnTiBi ferrite with large average grain size (>30μm) at 900°C. Firstly, the hybrid materials, including Li2CO3, ZnO, TiO2, Bi2O3 and Fe2O3, were pre-sintered at 850°C at O2 atmosphere. Next, composite additives composited of Li2CO3 and ZnO nanoparticles were added to control grain growth. The influences of the Li2CO3 and nano-ZnO (LZ) on the microstructure and magnetic properties of LiZnTiBi ferrite, especially for grain size, have been analyzed. SEM images demonstrated that moderate LZ additives (x=0.75 wt%) can prevent abnormal grains. Also, the ferrite samples possess compact microstructures. The phenomenon indicated that the LZ additive is a good sintering aid for low-temperature sintering LiZnTiBi ferrites. XRD patterns showed that all samples have a pure spinel phase. The magnetic properties, including Bs, Br/Bs and 4πMs, have weak change when LZ additives were added. However, due to smaller average grain size, the coercivity (Hc) gradually increased. Thus, a low-temperature sintering LiZnTiBi ferrite with high saturation flux density (Bs=311.10 mT), large remanence ratio (Br/Bs=0.86), low coercivity (Hc=244.6 A/m) and high saturation magnetization (Ms=75.40) was obtained when 1.00 wt% LZ additive was added. More important, the LiZnTiBi ferrite possessed uniform average grain. Such a sintering method (i.e., adding composite additive to control abnormal grain) should also promote synthesis of other advanced ceramics for practical applications.
LiZnTi铁氧体陶瓷具有高饱和磁通密度(Bs)、大剩磁比(Br/Bs)和高饱和磁化强度(4πMs)的特点，是高频器件的重要材料。在900℃下，制备了均匀致密、平均晶粒尺寸大(>30μm)的LiZnTiBi铁氧体。首先，将Li2CO3、ZnO、TiO2、Bi2O3和Fe2O3等杂化材料在850℃O2气氛下进行预烧结。然后，添加Li2CO3和ZnO纳米颗粒复合添加剂来控制晶粒生长。分析了Li2CO3和纳米zno (LZ)对LiZnTiBi铁氧体微观结构和磁性能的影响，特别是对晶粒尺寸的影响。SEM图像表明，适量的LZ添加剂(x=0.75 wt%)可以防止异常晶粒。此外，铁素体样品具有致密的微观结构。这一现象表明LZ添加剂是低温烧结LiZnTiBi铁氧体的良好助烧剂。XRD分析表明，所有样品均具有纯尖晶石相。添加LZ后，材料的磁性能Bs、Br/Bs和4πMs均有微弱变化。但由于平均晶粒尺寸变小，矫顽力(Hc)逐渐增大。因此，当添加1.00 wt% LZ时，可获得高饱和磁通密度(Bs=311.10 mT)、大剩磁比(Br/Bs=0.86)、低矫顽力(Hc=244.6 a /m)和高饱和磁化强度(Ms=75.40)的低温烧结LiZnTiBi铁氧体。更重要的是，litntibi铁氧体具有均匀的平均晶粒。这种烧结方法(即添加复合添加剂来控制异常晶粒)也应促进其他先进陶瓷的合成，以供实际应用。
{"title":"Influence of Li2CO3 and ZnO Nanoparticle on Microstructure and Magnetic Properties of Low-Temperature Sintering LiZnTiBi Ferrites for High-Frequency Applications","authors":"Fang Xu, Yulong Liao, Huaiwu Zhang","doi":"10.11648/J.IJMSA.20190803.11","DOIUrl":"https://doi.org/10.11648/J.IJMSA.20190803.11","url":null,"abstract":"LiZnTi ferrite ceramics with high saturation flux density (Bs), large remanence ratio (Br/Bs) and high saturation magnetization (4πMs) is a vital material for high frequency devices. In the present work, we prepared uniform and compact LiZnTiBi ferrite with large average grain size (>30μm) at 900°C. Firstly, the hybrid materials, including Li2CO3, ZnO, TiO2, Bi2O3 and Fe2O3, were pre-sintered at 850°C at O2 atmosphere. Next, composite additives composited of Li2CO3 and ZnO nanoparticles were added to control grain growth. The influences of the Li2CO3 and nano-ZnO (LZ) on the microstructure and magnetic properties of LiZnTiBi ferrite, especially for grain size, have been analyzed. SEM images demonstrated that moderate LZ additives (x=0.75 wt%) can prevent abnormal grains. Also, the ferrite samples possess compact microstructures. The phenomenon indicated that the LZ additive is a good sintering aid for low-temperature sintering LiZnTiBi ferrites. XRD patterns showed that all samples have a pure spinel phase. The magnetic properties, including Bs, Br/Bs and 4πMs, have weak change when LZ additives were added. However, due to smaller average grain size, the coercivity (Hc) gradually increased. Thus, a low-temperature sintering LiZnTiBi ferrite with high saturation flux density (Bs=311.10 mT), large remanence ratio (Br/Bs=0.86), low coercivity (Hc=244.6 A/m) and high saturation magnetization (Ms=75.40) was obtained when 1.00 wt% LZ additive was added. More important, the LiZnTiBi ferrite possessed uniform average grain. Such a sintering method (i.e., adding composite additive to control abnormal grain) should also promote synthesis of other advanced ceramics for practical applications.","PeriodicalId":14116,"journal":{"name":"International Journal of Materials Science and Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82129625","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 : 2019-07-04DOI: 10.11648/J.IJMSA.20190802.12
Danlami Umar Zuru, Balal Hassan, Muhammad Nuraddeen Bui, Aliyu Sa’ad Bk, Aliyu Jabbo Bunzah
Single walled carbon nanotubes (SWCNTs) are attractive in the nanotechnology industry where they find applications in the field of pharmacy and medicine due to high surface area capable of transporting drugs and vaccines to active sites; for fabrication of energy storing devices due to excellent electrical conductivity and accessible pore sizes; in transport for the fabrication of strong and lightweight vehicle and aircraft parts and in composite materials to enhance physical and chemical properties such as toughness, durability, conductivity and strength. The most efficient and cost effective method of obtaining these precious materials is the Chemical Vapour Deposition (CVD), however, obtaining SWCNTs of desired electronic type via this method, has remained a global challenge for over 20 years. This has limited the availability of these products in the global research and technological industries, contributing to the problem of lack of raw materials to sustain them. In this report, metallic SWCNTs (11, 8) are selectively synthesized via chemical vapor deposition (CVD) method, by the pyrolysis of C6H14/N2 feedstock on Fe2O3/Al2O3 catalyst matrix. Catalyst design and preparation was achieved by correlating the numerical magnitudes of chiral index (n, m) of the desired SWCNTs with mole fractions of metal/support, respectively. Field emission scanning electron microscopy analysis reveals densely entangled tubular bundles, while high resolution transmission electron microscopy confirms rigid arrangements of SWCNTs in the bundles. Values of the radial breathing modes, diameter and energy band gaps of the sample obtained from Raman analysis conforms to that of SWCNTs (11, 8), established via Extended Tight Binding (ETB) model. Outcome of this report suggested that our catalyst design and preparation may help alleviate the stated global challenge.
{"title":"Selective Synthesis and Characterization of Single Walled Carbon Nanotubes (11, 8)","authors":"Danlami Umar Zuru, Balal Hassan, Muhammad Nuraddeen Bui, Aliyu Sa’ad Bk, Aliyu Jabbo Bunzah","doi":"10.11648/J.IJMSA.20190802.12","DOIUrl":"https://doi.org/10.11648/J.IJMSA.20190802.12","url":null,"abstract":"Single walled carbon nanotubes (SWCNTs) are attractive in the nanotechnology industry where they find applications in the field of pharmacy and medicine due to high surface area capable of transporting drugs and vaccines to active sites; for fabrication of energy storing devices due to excellent electrical conductivity and accessible pore sizes; in transport for the fabrication of strong and lightweight vehicle and aircraft parts and in composite materials to enhance physical and chemical properties such as toughness, durability, conductivity and strength. The most efficient and cost effective method of obtaining these precious materials is the Chemical Vapour Deposition (CVD), however, obtaining SWCNTs of desired electronic type via this method, has remained a global challenge for over 20 years. This has limited the availability of these products in the global research and technological industries, contributing to the problem of lack of raw materials to sustain them. In this report, metallic SWCNTs (11, 8) are selectively synthesized via chemical vapor deposition (CVD) method, by the pyrolysis of C6H14/N2 feedstock on Fe2O3/Al2O3 catalyst matrix. Catalyst design and preparation was achieved by correlating the numerical magnitudes of chiral index (n, m) of the desired SWCNTs with mole fractions of metal/support, respectively. Field emission scanning electron microscopy analysis reveals densely entangled tubular bundles, while high resolution transmission electron microscopy confirms rigid arrangements of SWCNTs in the bundles. Values of the radial breathing modes, diameter and energy band gaps of the sample obtained from Raman analysis conforms to that of SWCNTs (11, 8), established via Extended Tight Binding (ETB) model. Outcome of this report suggested that our catalyst design and preparation may help alleviate the stated global challenge.","PeriodicalId":14116,"journal":{"name":"International Journal of Materials Science and Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76695246","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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