Jin Cui, Xihua Wang, Li Huang, Chengwei Zhang, Ye Yuan, Yibin Li
Biomass-derived porous carbon has attracted tremendous attention in many research fields due to its cheap and feasible strategy. In this work, bark-derived porous carbon composites (Co@PC) for microwave absorption applications was successfully prepared through a simple method. The minimum reflection loss (RLmin) of Co@PC (carbonized at 800°C, Co2+ concentration is 0.15 mol/L) is -49.2 dB at 10 GHz and a wide effective absorption bandwidth (EAB) of 6.16 GHz was obtained. Further, by adjusting carbonization temperature of the bark, the microwave absorption performance could be further enhanced. The results show that the RLmin could be -58.4 dB at 8.6 GHz when the bark was carbonized at 900°C. The retained channel structures of the bark played an important role in this excellent microwave absorbing performance. The channel walls with Co nanoparticles form a three-dimensional conductive network, endow conductive loss and magnetic loss of microwave energies. The channel structures provide transmission path for microwaves, which is not only cause multiple reflections and scattering of microwaves, but also benefit to the impedance matching. In addition, radar cross section (RCS) simulation results also demonstrates that Co@PC can be applied in the field of microwave absorption.
{"title":"Environmentally Friendly Bark-Derived Co-Doped Porous Carbon Composites for Microwave Absorption","authors":"Jin Cui, Xihua Wang, Li Huang, Chengwei Zhang, Ye Yuan, Yibin Li","doi":"10.2139/ssrn.3929268","DOIUrl":"https://doi.org/10.2139/ssrn.3929268","url":null,"abstract":"Biomass-derived porous carbon has attracted tremendous attention in many research fields due to its cheap and feasible strategy. In this work, bark-derived porous carbon composites (Co@PC) for microwave absorption applications was successfully prepared through a simple method. The minimum reflection loss (RLmin) of Co@PC (carbonized at 800°C, Co2+ concentration is 0.15 mol/L) is -49.2 dB at 10 GHz and a wide effective absorption bandwidth (EAB) of 6.16 GHz was obtained. Further, by adjusting carbonization temperature of the bark, the microwave absorption performance could be further enhanced. The results show that the RLmin could be -58.4 dB at 8.6 GHz when the bark was carbonized at 900°C. The retained channel structures of the bark played an important role in this excellent microwave absorbing performance. The channel walls with Co nanoparticles form a three-dimensional conductive network, endow conductive loss and magnetic loss of microwave energies. The channel structures provide transmission path for microwaves, which is not only cause multiple reflections and scattering of microwaves, but also benefit to the impedance matching. In addition, radar cross section (RCS) simulation results also demonstrates that Co@PC can be applied in the field of microwave absorption.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"66 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73758588","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}
R. Al-Mukadam, I. K. Goetz, M. Stolpe, J. Deubener
Fast-scanning calorimetry was applied to retrieve the viscosity of supercooled liquids of the Zr-based bulk metallic glasses (BMGs) Vitreloy 105 and AMZ4 for temperatures from standard glass transition down to ~0.78Tg/T. Characteristic temperatures of the glass transition were translated into viscosity values by means of composition-independent shift factors based on the equivalency between structural relaxation and viscous flow. The extended MYEGA model with a fragile term dominant at high-temperatures and a strong term dominant at low-temperatures describes the entire viscous range. The analysis revealed that Vitreloy 105 and AMZ4 are strong liquids for log10η ≥ 4.9–5.5. In turn, the fragile-to-strong crossover is centred on 0.69Tg/T for Vitreloy 105 and on 0.66Tg/T for AMZ4. The extent of the fragile-to-strong transition was found to be larger for Vitreloy 105 than for AMZ4, while their values agreed well with the inverse relation between transition factor and kinetic fragility of the strong regime established for BMG-forming liquids.
{"title":"Viscosity of Metallic Glass-Forming Liquids Based on Zr by Fast-Scanning Calorimetry","authors":"R. Al-Mukadam, I. K. Goetz, M. Stolpe, J. Deubener","doi":"10.2139/ssrn.3848997","DOIUrl":"https://doi.org/10.2139/ssrn.3848997","url":null,"abstract":"Fast-scanning calorimetry was applied to retrieve the viscosity of supercooled liquids of the Zr-based bulk metallic glasses (BMGs) Vitreloy 105 and AMZ4 for temperatures from standard glass transition down to ~0.78<i>T<sub>g</sub>/T</i>. Characteristic temperatures of the glass transition were translated into viscosity values by means of composition-independent shift factors based on the equivalency between structural relaxation and viscous flow. The extended MYEGA model with a fragile term dominant at high-temperatures and a strong term dominant at low-temperatures describes the entire viscous range. The analysis revealed that Vitreloy 105 and AMZ4 are strong liquids for log<sub>10</sub>η ≥ 4.9–5.5. In turn, the fragile-to-strong crossover is centred on 0.69<i>T<sub>g</sub>/T</i> for Vitreloy 105 and on 0.66<i>T<sub>g</sub>/T</i> for AMZ4. The extent of the fragile-to-strong transition was found to be larger for Vitreloy 105 than for AMZ4, while their values agreed well with the inverse relation between transition factor and kinetic fragility of the strong regime established for BMG-forming liquids.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85240728","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}
Huan Zhang, Yaqi Zhang, P. Yu, Li-Min Wang, Gong Li
Abstract Vitrification of Tellurium-based(Te) chalcogenid semiconductors is explored as a new route to enhance their thermoelectric properties by maximizing the degree of structural disorder to produce the minimum thermal conductivity. Ga2Te3-SnTe systems are focused in this paper and the optimized glass-forming composition is identified. Complete bulk (Ga2Te3)34(SnTe)66 glass is successfully prepared by a spark plasma sintering technique and exhibited an ultralow low thermal conductivity and high Seebeck coefficient. Together with the tunable electrical conductivity, the newly obtained Ga2Te3-SnTe glasses broaden the research scope of Te-based semiconductor glasses and also provide a new option for the development of high-performance thermoelectric materials.
{"title":"Preparation and Thermoelectric Properties of Novel Tellurium-Based Glassy Semiconductors","authors":"Huan Zhang, Yaqi Zhang, P. Yu, Li-Min Wang, Gong Li","doi":"10.2139/ssrn.3826730","DOIUrl":"https://doi.org/10.2139/ssrn.3826730","url":null,"abstract":"Abstract Vitrification of Tellurium-based(Te) chalcogenid semiconductors is explored as a new route to enhance their thermoelectric properties by maximizing the degree of structural disorder to produce the minimum thermal conductivity. Ga2Te3-SnTe systems are focused in this paper and the optimized glass-forming composition is identified. Complete bulk (Ga2Te3)34(SnTe)66 glass is successfully prepared by a spark plasma sintering technique and exhibited an ultralow low thermal conductivity and high Seebeck coefficient. Together with the tunable electrical conductivity, the newly obtained Ga2Te3-SnTe glasses broaden the research scope of Te-based semiconductor glasses and also provide a new option for the development of high-performance thermoelectric materials.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"05 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86303990","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}
Abstract In flowable slurry electrodes, charge transfer coincides with particle/particle and particle/current collector interactions, and it is challenging to investigate these effects experimentally. We present a novel CFD-DEM approach by introducing the charge transfer efficiency coefficient to model the charge transfer process in slurry electrodes. For the first time, we investigate the effects of contact and electrolyte resistances, and current collector shapes and configurations on percolation threshold and electric conductivity of slurry electrodes. Our results show that contact and electrolyte resistances play a vital role on efficiency of slurry electrodes. We show that, with a perpendicular current collector configuration the conductivity of slurry electrodes doubles as the velocity increases almost 3 orders of magnitude, while with a traditional parallel configuration it decreases by approximately 50% over the same velocity range. Additionally, we demonstrate that the charge percolation network associated with rapid increases in conductivity forms after 12 vol% with a perpendicular current collector and after 20 vol% with a parallel configuration. HTAB surfactant (5 mM) is used in the slurries to avoid agglomeration and sedimentation of the carbon particles in the channel. It decreased the conductivity of slurry electrodes by roughly 10% while reducing the viscosity by 30%.
{"title":"Effects of Current Collector Shape and Configuration on Charge Percolation and Electric Conductivity of Slurry Electrodes for Electrochemical Systems","authors":"A. Heidarian, S. Cheung, R. Ojha, G. Rosengarten","doi":"10.2139/ssrn.3893404","DOIUrl":"https://doi.org/10.2139/ssrn.3893404","url":null,"abstract":"Abstract In flowable slurry electrodes, charge transfer coincides with particle/particle and particle/current collector interactions, and it is challenging to investigate these effects experimentally. We present a novel CFD-DEM approach by introducing the charge transfer efficiency coefficient to model the charge transfer process in slurry electrodes. For the first time, we investigate the effects of contact and electrolyte resistances, and current collector shapes and configurations on percolation threshold and electric conductivity of slurry electrodes. Our results show that contact and electrolyte resistances play a vital role on efficiency of slurry electrodes. We show that, with a perpendicular current collector configuration the conductivity of slurry electrodes doubles as the velocity increases almost 3 orders of magnitude, while with a traditional parallel configuration it decreases by approximately 50% over the same velocity range. Additionally, we demonstrate that the charge percolation network associated with rapid increases in conductivity forms after 12 vol% with a perpendicular current collector and after 20 vol% with a parallel configuration. HTAB surfactant (5 mM) is used in the slurries to avoid agglomeration and sedimentation of the carbon particles in the channel. It decreased the conductivity of slurry electrodes by roughly 10% while reducing the viscosity by 30%.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87266389","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}
Summary Metal penetration into a solid electrolyte (SE) is one of the critical problems impeding the practical application of solid-state batteries. In this study, we investigate the conditions under which electronic conductivity of the SE can lead to metal deposition and fracture within the SE. Three different stages for void filling (metal plating initiation, metal growth, and metal compression) in the SE are identified. We show that a micron-size isolated void in the SE near the anode can be quickly filled in by metal and fractured when the developed pressure in the void grows larger than the maximum pressure the SE material can sustain. We find that the anode voltage and applied current density play a significant role in determining the vulnerability to metal deposition. We discuss several strategies to prevent electronic conductivity-driven metal propagation in electrolytes that are not fully dense, including the densified layers between the anode and SE.
{"title":"Understanding Metal Propagation in Solid Electrolytes Due to Mixed Ionic–Electronic Conduction","authors":"Qingsong Tu, Tan Shi, S. Chakravarthy, G. Ceder","doi":"10.2139/ssrn.3834690","DOIUrl":"https://doi.org/10.2139/ssrn.3834690","url":null,"abstract":"Summary Metal penetration into a solid electrolyte (SE) is one of the critical problems impeding the practical application of solid-state batteries. In this study, we investigate the conditions under which electronic conductivity of the SE can lead to metal deposition and fracture within the SE. Three different stages for void filling (metal plating initiation, metal growth, and metal compression) in the SE are identified. We show that a micron-size isolated void in the SE near the anode can be quickly filled in by metal and fractured when the developed pressure in the void grows larger than the maximum pressure the SE material can sustain. We find that the anode voltage and applied current density play a significant role in determining the vulnerability to metal deposition. We discuss several strategies to prevent electronic conductivity-driven metal propagation in electrolytes that are not fully dense, including the densified layers between the anode and SE.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76545836","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}
After a brief discussion about recommended velocities of the water in a disinfection channel, this paper presents a justification for allowing the use of higher velocities in the channel and consequently the need for smaller cross areas into which it would be easier to distribute disinfectant.
{"title":"Design of Disinfection Channel","authors":"Arturo Murillo M.","doi":"10.2139/ssrn.3915241","DOIUrl":"https://doi.org/10.2139/ssrn.3915241","url":null,"abstract":"After a brief discussion about recommended velocities of the water in a disinfection channel, this paper presents a justification for allowing the use of higher velocities in the channel and consequently the need for smaller cross areas into which it would be easier to distribute disinfectant.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85661505","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 : 2021-08-31DOI: 10.15587/2519-4852.2021.238806
K. Khokhlova, L. Vyshnevska, O. Zdoryk, O. Filatova
The aim of this work was to improve the approaches for standardization of Thymus L. species by development of HPTLC identification of phenolic compounds (flavonoids and phenylpropanoids) and terpenoids (essential oils and triterpenoids) and quantitative determination of rosmarinic acid and flavonoids for six Thymus L. species of Ukraine flora, as well as determination of chromatographic profiles of Thymus L. species’ extracts obtained using different extraction methods. Materials and methods. Objects were: samples of dry herb of Th.serpyllum, Th.vulgaris, Th.Marschallianus, Th.Pallasianus, Th.calcareus, and Th.moldavicus of Ukraine origin collected in 2019-2021 years or acquired commercially on Ukraine market. Instruments: CAMAG HPTLC Herbal System, visionCats 2.5. The analytical grade reagents were used. Reference substances were purchased from Extrasynthese, Sigma Aldrich. Chromatography was performed on HPTLC plates Si 60 F254, Merck according to the developed methods. Results. A new approach for quality control of different Thymus L. species of Ukraine flora included the development of HPTLC methods for identification of main groups of bioactive substances of these species, such as flavonoids and phenylpropanoids, essential oils, triterpenoids; development of quantification method of rosmarinic acid and assay of total flavonoids, expressed as luteolin-7-O-glucoside. The characteristic HPTLC fingerprints of six Thymus L. species in three mobile phases of different polarities that cover a wide range of bioactive substances were established. The content of rosmarinic acid in different Thymus L. species samples was in the range of 0,11-0,72 %: Th.moldavicus – 0,11 %; Th.Marschallianus – 0,19-0,27 %; Th.serpyllum – 0,38 %; Th.vulgaris – 0,51 %; Th.calcareus – 0,56 %; T.Pallasianus – 0,72 %. The total flavonoids content, expressed as luteolin-7-O-glucoside, was in the range of 0,8-2,72 %: Th.moldavicus – 0,8 %; Th.serpyllum – 0,87 %; Th.vulgaris – 1,06 %; Th.Pallasianus – 1,28 %; Th.Marschallianus – 1,89 %; Th.calcareus – 2,72 %. Conclusions. The proposed scientific approach for quality evaluation of Thymus L. species using HPTLC allows to determine comprehensive information of chemical composition and content of active substances of multiple samples in parallel, in a cost and time-efficient manner
{"title":"Application of Approach for Development of HPTLC Identification and Quantification Methods for Determination of Phenolic Compounds and Terpenoids of Several Thymus L. Species","authors":"K. Khokhlova, L. Vyshnevska, O. Zdoryk, O. Filatova","doi":"10.15587/2519-4852.2021.238806","DOIUrl":"https://doi.org/10.15587/2519-4852.2021.238806","url":null,"abstract":"The aim of this work was to improve the approaches for standardization of Thymus L. species by development of HPTLC identification of phenolic compounds (flavonoids and phenylpropanoids) and terpenoids (essential oils and triterpenoids) and quantitative determination of rosmarinic acid and flavonoids for six Thymus L. species of Ukraine flora, as well as determination of chromatographic profiles of Thymus L. species’ extracts obtained using different extraction methods. \u0000Materials and methods. Objects were: samples of dry herb of Th.serpyllum, Th.vulgaris, Th.Marschallianus, Th.Pallasianus, Th.calcareus, and Th.moldavicus of Ukraine origin collected in 2019-2021 years or acquired commercially on Ukraine market. Instruments: CAMAG HPTLC Herbal System, visionCats 2.5. The analytical grade reagents were used. Reference substances were purchased from Extrasynthese, Sigma Aldrich. Chromatography was performed on HPTLC plates Si 60 F254, Merck according to the developed methods. \u0000Results. A new approach for quality control of different Thymus L. species of Ukraine flora included the development of HPTLC methods for identification of main groups of bioactive substances of these species, such as flavonoids and phenylpropanoids, essential oils, triterpenoids; development of quantification method of rosmarinic acid and assay of total flavonoids, expressed as luteolin-7-O-glucoside. The characteristic HPTLC fingerprints of six Thymus L. species in three mobile phases of different polarities that cover a wide range of bioactive substances were established. The content of rosmarinic acid in different Thymus L. species samples was in the range of 0,11-0,72 %: Th.moldavicus – 0,11 %; Th.Marschallianus – 0,19-0,27 %; Th.serpyllum – 0,38 %; Th.vulgaris – 0,51 %; Th.calcareus – 0,56 %; T.Pallasianus – 0,72 %. The total flavonoids content, expressed as luteolin-7-O-glucoside, was in the range of 0,8-2,72 %: Th.moldavicus – 0,8 %; Th.serpyllum – 0,87 %; Th.vulgaris – 1,06 %; Th.Pallasianus – 1,28 %; Th.Marschallianus – 1,89 %; Th.calcareus – 2,72 %. \u0000Conclusions. The proposed scientific approach for quality evaluation of Thymus L. species using HPTLC allows to determine comprehensive information of chemical composition and content of active substances of multiple samples in parallel, in a cost and time-efficient manner","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84852541","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 : 2021-08-31DOI: 10.15587/1729-4061.2021.236984
N. Sytnik, Ekaterina Kunitsia, V. Mazaeva, V. Kalyna, A. Chernukha, S. Vazhynskyi, O. Yashchenko, Murat Maliarov, O. Bogatov, B. Bolibrukh
As a result of alkaline neutralization of oils, a significant amount of soapstock is formed, the utilization of which creates an environmental and economic problem. The production of fatty acids from soapstock using sulfuric acid decomposition is investigated in this work. The peculiarity of the work is the determination of regression dependences of the yield and neutralization number of fatty acids on the soapstock processing conditions: temperature and duration. Soapstock obtained after neutralization of sunflower oil was used as raw material. Soapstock indicators: mass fraction of moisture – 15.4 %, total fat – 71.9 %, fatty acids – 64.5 %, neutral fat – 7.4 %. Rational conditions of soapstock processing are determined: temperature (90–95) °С, duration 40 min. Under these conditions, the fatty acid yield is 79.0 %, the neutralization number is 180.0 mg KOH/g. Quality indicators of the obtained fatty acids: mass fraction of moisture and volatile substances – 1.8 %, mass fraction of total fat – 97.0 %, cleavage depth – 64.5 % of oleic acid, the presence of mineral acids – no. Fatty acids correspond to fatty acids of the first grade according to DSTU 4860 (CAS 61788-66-7). An increase in the temperature and duration of soapstock contact with sulfuric acid increases the yield and neutralization number of fatty acids. This is due to a decrease in the viscosity of the reaction medium, an increase in the depth of cleavage of soapstock soaps with sulfuric acid, an increase in the intensity and duration of mass transfer. The developed rational conditions allow obtaining fatty acids from soapstock, which correspond in composition to fatty acids from refined deodorized sunflower oil. The results allow solving a number of economic and environmental problems associated with soapstock utilization and can be implemented in oil refineries and fatty acid production
{"title":"Rational Conditions of Fatty Acids Obtaining by Soapstock Treatment with Sulfuric Acid","authors":"N. Sytnik, Ekaterina Kunitsia, V. Mazaeva, V. Kalyna, A. Chernukha, S. Vazhynskyi, O. Yashchenko, Murat Maliarov, O. Bogatov, B. Bolibrukh","doi":"10.15587/1729-4061.2021.236984","DOIUrl":"https://doi.org/10.15587/1729-4061.2021.236984","url":null,"abstract":"As a result of alkaline neutralization of oils, a significant amount of soapstock is formed, the utilization of which creates an environmental and economic problem. The production of fatty acids from soapstock using sulfuric acid decomposition is investigated in this work.\u0000The peculiarity of the work is the determination of regression dependences of the yield and neutralization number of fatty acids on the soapstock processing conditions: temperature and duration.\u0000Soapstock obtained after neutralization of sunflower oil was used as raw material. Soapstock indicators: mass fraction of moisture – 15.4 %, total fat – 71.9 %, fatty acids – 64.5 %, neutral fat – 7.4 %.\u0000Rational conditions of soapstock processing are determined: temperature (90–95) °С, duration 40 min. Under these conditions, the fatty acid yield is 79.0 %, the neutralization number is 180.0 mg KOH/g. Quality indicators of the obtained fatty acids: mass fraction of moisture and volatile substances – 1.8 %, mass fraction of total fat – 97.0 %, cleavage depth – 64.5 % of oleic acid, the presence of mineral acids – no. Fatty acids correspond to fatty acids of the first grade according to DSTU 4860 (CAS 61788-66-7).\u0000An increase in the temperature and duration of soapstock contact with sulfuric acid increases the yield and neutralization number of fatty acids. This is due to a decrease in the viscosity of the reaction medium, an increase in the depth of cleavage of soapstock soaps with sulfuric acid, an increase in the intensity and duration of mass transfer.\u0000The developed rational conditions allow obtaining fatty acids from soapstock, which correspond in composition to fatty acids from refined deodorized sunflower oil.\u0000The results allow solving a number of economic and environmental problems associated with soapstock utilization and can be implemented in oil refineries and fatty acid production","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74385245","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 : 2021-08-31DOI: 10.15587/1729-4061.2021.238266
Zheng Hu, Oleksii Vambol, Shiping Sun, Q. Zeng
Composite lattice ring structures are known for their lightweight and high efficiency, which have a strong attraction in the aeronautical and aerospace industries. The general manufacturing process for such structures is to use wet filament winding technology. Due to the anisotropic properties of continuous fibers, the filament winding trajectory determines the mechanical properties of the composite lattice ring structures. In this work, a topology optimization method is proposed to generate the efficient filament winding trajectory, which follows the load transfer path of the composite part and can offer higher mechanical strengths. To satisfy the periodicity requirement of the structure, the design space is divided into a prescribed number of identical substructures during the topology optimization process. In order to verify the effectiveness and capability of the proposed approach, the topological design of ring structures with the different number of substructures, the ratio of outer to inner radius and the loading case is investigated. The results reflect that the optimal topology shape strongly depends on the substructure numbers, radius ratio and loading case. Moreover, the compliance of the optimized structures increases with the total number of substructures, while the structural efficiency of the optimized structures decreases with the radius ratio. Finally, taking the specified topological structure as the object, the conceptual design of a robotic filament winding system for manufacturing the composite lattice ring structure is presented. In particular, the forming tooling, integrated deposition system, winding trajectory and manufacturing process are carefully defined, which can provide valuable references for practical production in the future
{"title":"Development of a Topology Optimization Method for the Design of Composite Lattice Ring Structures","authors":"Zheng Hu, Oleksii Vambol, Shiping Sun, Q. Zeng","doi":"10.15587/1729-4061.2021.238266","DOIUrl":"https://doi.org/10.15587/1729-4061.2021.238266","url":null,"abstract":"Composite lattice ring structures are known for their lightweight and high efficiency, which have a strong attraction in the aeronautical and aerospace industries. The general manufacturing process for such structures is to use wet filament winding technology. Due to the anisotropic properties of continuous fibers, the filament winding trajectory determines the mechanical properties of the composite lattice ring structures. In this work, a topology optimization method is proposed to generate the efficient filament winding trajectory, which follows the load transfer path of the composite part and can offer higher mechanical strengths. To satisfy the periodicity requirement of the structure, the design space is divided into a prescribed number of identical substructures during the topology optimization process. In order to verify the effectiveness and capability of the proposed approach, the topological design of ring structures with the different number of substructures, the ratio of outer to inner radius and the loading case is investigated. The results reflect that the optimal topology shape strongly depends on the substructure numbers, radius ratio and loading case. Moreover, the compliance of the optimized structures increases with the total number of substructures, while the structural efficiency of the optimized structures decreases with the radius ratio. Finally, taking the specified topological structure as the object, the conceptual design of a robotic filament winding system for manufacturing the composite lattice ring structure is presented. In particular, the forming tooling, integrated deposition system, winding trajectory and manufacturing process are carefully defined, which can provide valuable references for practical production in the future","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"29 48","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91417730","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 : 2021-07-31DOI: 10.15587/2706-5448.2021.237447
V. Pashynskyi, I. Boyko
The object of research is hard alloys with a morphology of the carbide phase skeleton structure, in which particles contact with each other, and the gaps between them are filled with a binder phase. The mechanical and service characteristics of such materials depend on the degree of development of the skeleton structure. One of the most problematic areas is the lack of non-destructive methods for determining the parameters of the structure. The introduction of such techniques will allow obtaining objective information on the structure of the material and using it to evaluate the quality of products. In the course of the study, the parameters of the scattering of elastic vibrations in inhomogeneous media were determined. The main hypothesis of the study is the assumption that the processes of energy dissipation occur both in the structural elements themselves (carbide grains and bond areas) and at their boundaries. Therefore, the evaluation of dissipation processes will allow obtaining a quantitative estimation of the alloys structure parameters, and will allow assessing the quality of the material. The following characteristics were chosen as the parameters characterizing the propagation of ultrasonic oscillations: the speed of the oscillations propagation, the scattering background level in relation to the amplitude of the bottom reflection, the oscillations attenuation coefficient. The parameters were determined and compared with the characteristics of the quality of the products and the parameters of the microstructure, which were determined by the methods of quantitative metallography and the statistical characteristics of the relationship between the parameters, were determined. As a result, new quality control procedures for carbide products have been developed. The contiguity characteristics of the carbide skeleton of the sintered cemented carbide were determined by measuring the propagation speed of ultrasonic oscillations. The assessment of the level of porosity with a pore size of less than 1 mm was carried out according to the results of measuring the relative amplitude of the background scattering of ultrasonic oscillations. The proposed methods are non-destructive and are carried out in one cycle with ultrasonic flaw detection, to which 100% of the products are subjected. These techniques have been introduced in the production of carbide rolls by the method of controlled hot vacuum pressing. They have become an integral part of the quality control system for carbide rolls.
{"title":"Development of Quality Control and Structure Parameters Determination Methods for Large Size Products From Sintered Hard Alloys WC-(Co+Ni+Cr) Based on Analysis of the Ultrasonic Oscillations Spreading Parameters","authors":"V. Pashynskyi, I. Boyko","doi":"10.15587/2706-5448.2021.237447","DOIUrl":"https://doi.org/10.15587/2706-5448.2021.237447","url":null,"abstract":"The object of research is hard alloys with a morphology of the carbide phase skeleton structure, in which particles contact with each other, and the gaps between them are filled with a binder phase. The mechanical and service characteristics of such materials depend on the degree of development of the skeleton structure. One of the most problematic areas is the lack of non-destructive methods for determining the parameters of the structure. The introduction of such techniques will allow obtaining objective information on the structure of the material and using it to evaluate the quality of products. In the course of the study, the parameters of the scattering of elastic vibrations in inhomogeneous media were determined. The main hypothesis of the study is the assumption that the processes of energy dissipation occur both in the structural elements themselves (carbide grains and bond areas) and at their boundaries. Therefore, the evaluation of dissipation processes will allow obtaining a quantitative estimation of the alloys structure parameters, and will allow assessing the quality of the material. The following characteristics were chosen as the parameters characterizing the propagation of ultrasonic oscillations: the speed of the oscillations propagation, the scattering background level in relation to the amplitude of the bottom reflection, the oscillations attenuation coefficient. The parameters were determined and compared with the characteristics of the quality of the products and the parameters of the microstructure, which were determined by the methods of quantitative metallography and the statistical characteristics of the relationship between the parameters, were determined. As a result, new quality control procedures for carbide products have been developed. The contiguity characteristics of the carbide skeleton of the sintered cemented carbide were determined by measuring the propagation speed of ultrasonic oscillations. The assessment of the level of porosity with a pore size of less than 1 mm was carried out according to the results of measuring the relative amplitude of the background scattering of ultrasonic oscillations. The proposed methods are non-destructive and are carried out in one cycle with ultrasonic flaw detection, to which 100% of the products are subjected. These techniques have been introduced in the production of carbide rolls by the method of controlled hot vacuum pressing. They have become an integral part of the quality control system for carbide rolls.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"82 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81969895","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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