M. Islam, Kamaru zzaman, Mohammad Jellur Rahman, Md. Monjarul Alam
Natural fiber-reinforced nanocomposites (NFRCs) are proved as the best alternative for synthetic composites in view of cost and environmental effects. NFRCs have been produced from agro-waste such as banana tree fiber (BFs), because of BF are strong, light-weight, have smaller elongation. To improve the quality of BF, multiwall carbon nanotubes (MWCNTs) are used as reinforcing filler, which are functionalized by an ecofriendly radio frequency oxygen plasma processing method. cellulose nano-crystals (CNC) is extracted from BFs by double hydrolysis process and a simple dip-drying technique has been used to produce NFRCs. Field emission scanning electron micrographs and transmission electron microscopy conform the well dispersion of MWCNTs in the BF matrix. Thermal stability and mechanical strength of the NFRCs are improved owing to the incorporation of MWCNTs. Functional groups in the BFs, CNC and NFRCs are investigated by Fourier transform infrared spectroscopy. The current density of the sample is increased 1000 times and conductivity increases up to 17 Sm−1, which increases with temperature. Therefore, these light-weight biodegradable NFRCs encourage its ability as cost effective industrial conductive composite as usable in electronic devices.
{"title":"Carbon Nanotube Reinforced Natural Fibers for Biodegradable Nanocomposites","authors":"M. Islam, Kamaru zzaman, Mohammad Jellur Rahman, Md. Monjarul Alam","doi":"10.2139/ssrn.3909870","DOIUrl":"https://doi.org/10.2139/ssrn.3909870","url":null,"abstract":"Natural fiber-reinforced nanocomposites (NFRCs) are proved as the best alternative for synthetic composites in view of cost and environmental effects. NFRCs have been produced from agro-waste such as banana tree fiber (BFs), because of BF are strong, light-weight, have smaller elongation. To improve the quality of BF, multiwall carbon nanotubes (MWCNTs) are used as reinforcing filler, which are functionalized by an ecofriendly radio frequency oxygen plasma processing method. cellulose nano-crystals (CNC) is extracted from BFs by double hydrolysis process and a simple dip-drying technique has been used to produce NFRCs. Field emission scanning electron micrographs and transmission electron microscopy conform the well dispersion of MWCNTs in the BF matrix. Thermal stability and mechanical strength of the NFRCs are improved owing to the incorporation of MWCNTs. Functional groups in the BFs, CNC and NFRCs are investigated by Fourier transform infrared spectroscopy. The current density of the sample is increased 1000 times and conductivity increases up to 17 Sm−1, which increases with temperature. Therefore, these light-weight biodegradable NFRCs encourage its ability as cost effective industrial conductive composite as usable in electronic devices.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"98 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76039547","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}
O. Shrestha, A. Kapali, B. Thapa, H. Neopane, Young-Ho Lee
Several research studies have been conducted on the development of erosion-resistant alloys, coatings, and optimized hydraulic design of components to overcome sediment erosion-induced problems in hydro turbines. This research work has attempted to investigate the erosion wear on CFT blades made up of different materials and coatings, using a modified version of Rotating Disc Apparatus (RDA). The main consideration in designing the RDA is to accelerate the rotating speed and the relative velocity to achieve rapid erosion results. The materials of blades used for the experiment were SUS304, SUS440C, SUS630, SCM440, and STD11. These test specimens were exposed to a high sediment concentration of 127000 ppm. From the calculated amount of erosion and erosion rate data that the rate of erosion exhibits a strong relationship to characteristics of the material, such as mechanical and chemical properties. The estimation further suggests that the coated specimens follow a similar trend as of the parent materials’ erosion rate with an increase in the time of exposure to erosion. The numerical study was used to compare hydrodynamic flow visualization in an RDA and CFT turbine. RDA establish a similar velocity pattern and pressure along the surfaces of specimen nonetheless vortex is formed between them.
{"title":"Rotating Disc Apparatus (RDA) for Estimation of Erosion in Micro Crossflow Hydro Turbines","authors":"O. Shrestha, A. Kapali, B. Thapa, H. Neopane, Young-Ho Lee","doi":"10.2139/ssrn.3885516","DOIUrl":"https://doi.org/10.2139/ssrn.3885516","url":null,"abstract":"Several research studies have been conducted on the development of erosion-resistant alloys, coatings, and optimized hydraulic design of components to overcome sediment erosion-induced problems in hydro turbines. This research work has attempted to investigate the erosion wear on CFT blades made up of different materials and coatings, using a modified version of Rotating Disc Apparatus (RDA). The main consideration in designing the RDA is to accelerate the rotating speed and the relative velocity to achieve rapid erosion results. The materials of blades used for the experiment were SUS304, SUS440C, SUS630, SCM440, and STD11. These test specimens were exposed to a high sediment concentration of 127000 ppm. From the calculated amount of erosion and erosion rate data that the rate of erosion exhibits a strong relationship to characteristics of the material, such as mechanical and chemical properties. The estimation further suggests that the coated specimens follow a similar trend as of the parent materials’ erosion rate with an increase in the time of exposure to erosion. The numerical study was used to compare hydrodynamic flow visualization in an RDA and CFT turbine. RDA establish a similar velocity pattern and pressure along the surfaces of specimen nonetheless vortex is formed between them.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76835857","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}
Haiwei Wang, Xiao-li Zhang, J. Meng, Jinxia Yang, Yan-hong Yang, Yi-zhou Zhou, Xiao-feng Sun
The dominant factor of competitive grain growth was studied by trinary-crystal seeds during directional solidification. It was found that the grain overgrowth rate was weakly dependent on the temperature gradient when the misorientation angle of the misoriented grain was limited (£15°), which was inconsistent with the classical theoretical assumption that the grain overgrowth rate was determined by the difference of the tip undercooling between the competing grains. In contrast, the grain overgrowth rate was sensitive to the alloy composition. These phenomena were attributed to the mechanisms of solute interaction and sidebranching events, and the solute field was the dominant factor to govern the overgrowth behavior of the competing grains.
{"title":"The Dominant Factor of Competitive Grain Growth of the Nickel-Based Superalloys During Directional Solidification","authors":"Haiwei Wang, Xiao-li Zhang, J. Meng, Jinxia Yang, Yan-hong Yang, Yi-zhou Zhou, Xiao-feng Sun","doi":"10.2139/ssrn.3762200","DOIUrl":"https://doi.org/10.2139/ssrn.3762200","url":null,"abstract":"The dominant factor of competitive grain growth was studied by trinary-crystal seeds during directional solidification. It was found that the grain overgrowth rate was weakly dependent on the temperature gradient when the misorientation angle of the misoriented grain was limited (£15°), which was inconsistent with the classical theoretical assumption that the grain overgrowth rate was determined by the difference of the tip undercooling between the competing grains. In contrast, the grain overgrowth rate was sensitive to the alloy composition. These phenomena were attributed to the mechanisms of solute interaction and sidebranching events, and the solute field was the dominant factor to govern the overgrowth behavior of the competing grains.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80359676","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}
Xinxin Zhao, Jia Shi, Q. Yin, Zhuo Dong, Yan Zhang, Lixing Kang, Qiang Yu, Cheng Chen, Jie Li, Xin-Fu Liu, Kai Zhang
Recently, as an elementary material, tellurium (Te) has received widespread attention for its high carrier mobility, intriguing topological properties and excellent environmental stability. However, it is difficult to obtain two-dimensional (2D) Te with high crystalline quality due to its intrinsic helical chain structure. Herein, a facile strategy for controllable synthesis of high quality 2D Te nanoflakes through chemical vapor transport (CVT) in one step is reported. With carefully tuning the growth kinetics determined mainly by temperature, tellurium nanoflakes in lateral size of up to ~40 μm with high crystallinity can be achieved. We also investigated the second harmonic generation (SHG) of Te nanoflakes, which demonstrates that it can be used as frequency doubling crystals and has potential applications in nonlinear optical devices. In addition, field effect transistor (FET) devices based on the as-grown 2D Te nanoflakes were fabricated and exhibited excellent electrical properties with high mobility of 379 cm2 V-1s-1.
{"title":"A Facile Strategy for Controllable Synthesis of High-Quality Two-Dimensional Tellurium by Chemical Vapor Transport","authors":"Xinxin Zhao, Jia Shi, Q. Yin, Zhuo Dong, Yan Zhang, Lixing Kang, Qiang Yu, Cheng Chen, Jie Li, Xin-Fu Liu, Kai Zhang","doi":"10.2139/ssrn.3917174","DOIUrl":"https://doi.org/10.2139/ssrn.3917174","url":null,"abstract":"Recently, as an elementary material, tellurium (Te) has received widespread attention for its high carrier mobility, intriguing topological properties and excellent environmental stability. However, it is difficult to obtain two-dimensional (2D) Te with high crystalline quality due to its intrinsic helical chain structure. Herein, a facile strategy for controllable synthesis of high quality 2D Te nanoflakes through chemical vapor transport (CVT) in one step is reported. With carefully tuning the growth kinetics determined mainly by temperature, tellurium nanoflakes in lateral size of up to ~40 μm with high crystallinity can be achieved. We also investigated the second harmonic generation (SHG) of Te nanoflakes, which demonstrates that it can be used as frequency doubling crystals and has potential applications in nonlinear optical devices. In addition, field effect transistor (FET) devices based on the as-grown 2D Te nanoflakes were fabricated and exhibited excellent electrical properties with high mobility of 379 cm2 V-1s-1.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"94 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86414486","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}
E. Ze, T. Tchotang, W. Nzié, N. Billong, B. Kenmeugne
This work involves calculating the mechanical characteristics of bio-composites reinforced with plant fibers and plant particles from semi-empirical formulas and comparing them with the results obtained experimentally, the aim of this approach being to determine the analytical model which gives results close to experimental results with the aim of reducing the delays linked to the experimental characterization of composites with reinforcement of Cameroonian fibers and particles. To carry out this work, we used the mechanical characteristics of the fibers of the trunks of Carica papaya, of the petioles of Elaeis guineensis and of the particles of the nuclei canarium schweinfurthii (black fruit); these elements were collected in the regions of Center and West Cameroon. These features have been implemented in the semi-empirical models of Voigt, Reuss, Hirsch, and Alpine-Tsai. From these implementations, it emerged on the one hand a framework of the constitutive law with the longitudinal modulus resulting from each semi-empirical model. On the other hand, the models of Voigt, Hopkins-Chamis and Halpin-Tsai best approach the experimental results for fiber-reinforced composite materials (papaya trunk and oil palm petioles), while the models of Voigt and Hopkins-Chamis are ideal for composites with reinforcement of black fruit kernel particles. Regarding the transverse moduli, the Hopkins-Chamis model gives higher values than those obtained from the halpin-Tsai model. The Hopkins-Chamis and Halpin-Tsai models are best suited because they take into account the Voigt estimate.
{"title":"Analytical Determination of Mechanical Characteristics of Bio-Composites with Reinforcement of Fibers and Particles of Cameroonian's Plants","authors":"E. Ze, T. Tchotang, W. Nzié, N. Billong, B. Kenmeugne","doi":"10.2139/ssrn.3906489","DOIUrl":"https://doi.org/10.2139/ssrn.3906489","url":null,"abstract":"This work involves calculating the mechanical characteristics of bio-composites reinforced with plant fibers and plant particles from semi-empirical formulas and comparing them with the results obtained experimentally, the aim of this approach being to determine the analytical model which gives results close to experimental results with the aim of reducing the delays linked to the experimental characterization of composites with reinforcement of Cameroonian fibers and particles. To carry out this work, we used the mechanical characteristics of the fibers of the trunks of Carica papaya, of the petioles of Elaeis guineensis and of the particles of the nuclei canarium schweinfurthii (black fruit); these elements were collected in the regions of Center and West Cameroon. These features have been implemented in the semi-empirical models of Voigt, Reuss, Hirsch, and Alpine-Tsai. From these implementations, it emerged on the one hand a framework of the constitutive law with the longitudinal modulus resulting from each semi-empirical model. On the other hand, the models of Voigt, Hopkins-Chamis and Halpin-Tsai best approach the experimental results for fiber-reinforced composite materials (papaya trunk and oil palm petioles), while the models of Voigt and Hopkins-Chamis are ideal for composites with reinforcement of black fruit kernel particles. Regarding the transverse moduli, the Hopkins-Chamis model gives higher values than those obtained from the halpin-Tsai model. The Hopkins-Chamis and Halpin-Tsai models are best suited because they take into account the Voigt estimate.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87081402","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}
Chong Gao, X. Yan, Mupeng Zheng, Xin Gao, K. Zhao, Ling Li, M. Zhu, Y. Hou
Transduction coefficient ( d33 × g33 ) is the core parameter for evaluating piezoelectric energy harvesting materials. However, due to the thermodynamic constraints, the synergistic variation between piezoelectric charge constant ( d33 ) and dielectric constant ( εr ) indeed hinder the further increase of d33 × g33 . Herein, an exceptionally high d33 ×g33 of 13167×10−15m2 /N was achieved in 0.80BaTiO3 -0.10CaTiO3 -0.10BaZrO3 (BC0.1ZT) lead-free solid solution for the first time through a phase boundary engineering strategy. The high d33 × g33 mainly stems from non-synergistic variation of dielectricity and piezoelectricity in a new R-O phase boundary , in which the low εr comes from the increased domain size and reduced domain wall density , while the high configurational sensitivity of the unique domains to external electric field contributed to the high d33 on the left side of polymorphic phase boundary (PPB). Our findings provide an alternative approach for enhanced energy harvesting performance by tracing the strategy of designing phase boundary to decouple d33 and εr .
{"title":"Exceptionally High Transduction Coefficient in BaTiO 3-Based Piezoceramic Through Phase Boundary Engineering","authors":"Chong Gao, X. Yan, Mupeng Zheng, Xin Gao, K. Zhao, Ling Li, M. Zhu, Y. Hou","doi":"10.2139/ssrn.3919738","DOIUrl":"https://doi.org/10.2139/ssrn.3919738","url":null,"abstract":"Transduction coefficient ( d33 × g33 ) is the core parameter for evaluating piezoelectric energy harvesting materials. However, due to the thermodynamic constraints, the synergistic variation between piezoelectric charge constant ( d33 ) and dielectric constant ( εr ) indeed hinder the further increase of d33 × g33 . Herein, an exceptionally high d33 ×g33 of 13167×10−15m2 /N was achieved in 0.80BaTiO3 -0.10CaTiO3 -0.10BaZrO3 (BC0.1ZT) lead-free solid solution for the first time through a phase boundary engineering strategy. The high d33 × g33 mainly stems from non-synergistic variation of dielectricity and piezoelectricity in a new R-O phase boundary , in which the low εr comes from the increased domain size and reduced domain wall density , while the high configurational sensitivity of the unique domains to external electric field contributed to the high d33 on the left side of polymorphic phase boundary (PPB). Our findings provide an alternative approach for enhanced energy harvesting performance by tracing the strategy of designing phase boundary to decouple d33 and εr .","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"86 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78681541","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}
Dengshan Zhou, Yifan Bu, O. Muránsky, H. Geng, Binhan Sun, Chao Yang, Deliang Zhang
This work shows that the elongated grains that contain subgrains in bulk ultrafine-grained Al and Al-(2.5, 5 and 7.5)at.%Mg samples, fabricated by mechanical alloying and rapid powder consolidation, recrystallize to develop finer equiaxed matrix grains during subsequent annealing. The annealing also promotes formation of nanoscale oxide particles. The high number density oxide nanoparticles and fine recrystallized grains warrant high thermal stability and enhanced strength of the annealed samples while maintaining the good ductility of their as-extruded counterparts. The present experimental findings offer an exciting pathway in developing high thermal stability ultrafine-grained Al-Mg based alloys with a notable combination of high strength and good ductility.
{"title":"Annealing-Induced Grain Refinement and Hardening in Ultrafine-Grained Al and Al-Mg Alloys","authors":"Dengshan Zhou, Yifan Bu, O. Muránsky, H. Geng, Binhan Sun, Chao Yang, Deliang Zhang","doi":"10.2139/ssrn.3881876","DOIUrl":"https://doi.org/10.2139/ssrn.3881876","url":null,"abstract":"This work shows that the elongated grains that contain subgrains in bulk ultrafine-grained Al and Al-(2.5, 5 and 7.5)at.%Mg samples, fabricated by mechanical alloying and rapid powder consolidation, recrystallize to develop finer equiaxed matrix grains during subsequent annealing. The annealing also promotes formation of nanoscale oxide particles. The high number density oxide nanoparticles and fine recrystallized grains warrant high thermal stability and enhanced strength of the annealed samples while maintaining the good ductility of their as-extruded counterparts. The present experimental findings offer an exciting pathway in developing high thermal stability ultrafine-grained Al-Mg based alloys with a notable combination of high strength and good ductility.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88175934","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}
W. Geng, Gun Huang, Shengli Guo, Changbao Jiang, Ziwen Dong, Wensong Wang
Gas hazard is still one of the most severe disasters in coal mining, and its occurrence is inseparable from the interaction of coal and gas. In order to study the influence of adsorbable gas on coal pore structures and mechanical strength, coal specimens were placed in a low-pressure environment of CH4 or CO2 for 30 days to ensure that the specimens were saturated and fully interacted with the gas. Low-pressure nitrogen adsorption, scanning electron microscope, X-ray diffraction, and uniaxial compressive strength tests were employed to study coal's microstructure change and strength characteristics. The results showed that after CH4 or CO2 treatment, the proportion of macropores increases by 38.87% and 22.89%, and that of mesopores decrease by 6.34% and 3.73%, respectively, which indicates the evolution of mesopores to macropores and the formation of new pores. The microcrystalline structure parameters change obviously after long-term gas adsorption treatment. The values of d002 and d100 increase, while Lc , La , and Mc's values both decrease, resulting in a loose coal structure. Besides, a conceptual model is proposed to explain the evolution mechanism of pore structures under the effect of long-term gas adsorption.
{"title":"Experimental Study of Long-Term Gas Adsorption Effect on Pore Structures and Mechanical Strength Characteristics of Coal","authors":"W. Geng, Gun Huang, Shengli Guo, Changbao Jiang, Ziwen Dong, Wensong Wang","doi":"10.2139/ssrn.3899286","DOIUrl":"https://doi.org/10.2139/ssrn.3899286","url":null,"abstract":"Gas hazard is still one of the most severe disasters in coal mining, and its occurrence is inseparable from the interaction of coal and gas. In order to study the influence of adsorbable gas on coal pore structures and mechanical strength, coal specimens were placed in a low-pressure environment of CH4 or CO2 for 30 days to ensure that the specimens were saturated and fully interacted with the gas. Low-pressure nitrogen adsorption, scanning electron microscope, X-ray diffraction, and uniaxial compressive strength tests were employed to study coal's microstructure change and strength characteristics. The results showed that after CH4 or CO2 treatment, the proportion of macropores increases by 38.87% and 22.89%, and that of mesopores decrease by 6.34% and 3.73%, respectively, which indicates the evolution of mesopores to macropores and the formation of new pores. The microcrystalline structure parameters change obviously after long-term gas adsorption treatment. The values of d002 and d100 increase, while Lc , La , and Mc's values both decrease, resulting in a loose coal structure. Besides, a conceptual model is proposed to explain the evolution mechanism of pore structures under the effect of long-term gas adsorption.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88855343","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}
A. Abakumov, I. Bychko, O. Selyshchev, D. Zahn, M. Chen, J. Tang, P. Strizhak
Nitrogen-doped reduced graphene oxide (N-RGO) was synthesized by the treatment of graphene oxide with hydrazine. The obtained material was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman , nitrogen adsorption-desorption isotherm, and XPS. The catalytic activity of N-RGO in acetylene, ethylene hydrogenation, and preferential acetylene hydrogenation in the ethylene excess was determined. In the acetylene hydrogenation, the selectivity of 97% for ethylene is achieved. A possibility of a complete conversion of acetylene to ethylene in the acetylene-ethylene mixture with ratio 1:9 is shown.
{"title":"Highly Selective Hydrogenation of Acetylene Over Reduced Graphene Oxide Carbocatalyst","authors":"A. Abakumov, I. Bychko, O. Selyshchev, D. Zahn, M. Chen, J. Tang, P. Strizhak","doi":"10.2139/ssrn.3757897","DOIUrl":"https://doi.org/10.2139/ssrn.3757897","url":null,"abstract":"Nitrogen-doped reduced graphene oxide (N-RGO) was synthesized by the treatment of graphene oxide with hydrazine. The obtained material was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman , nitrogen adsorption-desorption isotherm, and XPS. The catalytic activity of N-RGO in acetylene, ethylene hydrogenation, and preferential acetylene hydrogenation in the ethylene excess was determined. In the acetylene hydrogenation, the selectivity of 97% for ethylene is achieved. A possibility of a complete conversion of acetylene to ethylene in the acetylene-ethylene mixture with ratio 1:9 is shown.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"135 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86380453","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}
M. Bouyer, C. Garot, P. Machillot, J. Vollaire, V. Fitzpatrick, S. Morand, J. Boutonnat, V. Josserand, G. Bettega, C. Picart
the reconstruction of large bone defects (12 cm3) remains a challenge for clinicians. We developed a new critical-size mandibular bone defect model on a mini-pig, close to human clinical issues. We analyzed the bone reconstruction obtained by a 3D printed scaffold made of clinical-grade PLA, coated with a polyelectrolyte film delivering an osteogenic bioactive molecule (BMP-2). We compared the results (CT-scan, μCT, histology) to the gold standard solution, bone autograft. We demonstrated that the dose of BMP-2 delivered from the scaffold significantly influenced the amount of regenerated bone and the repair kinetics, with a clear BMP-2 dose-dependence. Bone was homogeneously formed inside the scaffold without ectopic bone formation. The bone repair was as good as for the bone autograft. The BMP-2 doses applied in our study were reduced 20 to 75-fold compared to the commercial collagen sponges used in the current clinical applications, without any adverse effects. 3D printed PLA scaffolds loaded with reduced doses of BMP-2 can be a safe and simple solution for large bone defects faced in the clinic.
{"title":"3D Printed Scaffold Combined to 2D Osteoinductive Coatings To Repair a Critical-Size Mandibular Bone Defect","authors":"M. Bouyer, C. Garot, P. Machillot, J. Vollaire, V. Fitzpatrick, S. Morand, J. Boutonnat, V. Josserand, G. Bettega, C. Picart","doi":"10.2139/ssrn.3751567","DOIUrl":"https://doi.org/10.2139/ssrn.3751567","url":null,"abstract":"the reconstruction of large bone defects (12 cm3) remains a challenge for clinicians. We developed a new critical-size mandibular bone defect model on a mini-pig, close to human clinical issues. We analyzed the bone reconstruction obtained by a 3D printed scaffold made of clinical-grade PLA, coated with a polyelectrolyte film delivering an osteogenic bioactive molecule (BMP-2). We compared the results (CT-scan, μCT, histology) to the gold standard solution, bone autograft. We demonstrated that the dose of BMP-2 delivered from the scaffold significantly influenced the amount of regenerated bone and the repair kinetics, with a clear BMP-2 dose-dependence. Bone was homogeneously formed inside the scaffold without ectopic bone formation. The bone repair was as good as for the bone autograft. The BMP-2 doses applied in our study were reduced 20 to 75-fold compared to the commercial collagen sponges used in the current clinical applications, without any adverse effects. 3D printed PLA scaffolds loaded with reduced doses of BMP-2 can be a safe and simple solution for large bone defects faced in the clinic.","PeriodicalId":18268,"journal":{"name":"Materials Engineering eJournal","volume":"18 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91399265","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：