Pub Date : 2020-12-22DOI: 10.15587/1729-4061.2020.217674
A. V. Sagalovych, V. Popov, Vladislav Sagalovуch, S. Dudnik, Vladimir Bogoslavzev, N. Stadnichenko, A. Edinovych
This paper reports comparative tribotechnical tests of surfaces, hardened by cementation and plasma nitriding Avinit N, for contact fatigue strength at friction in rolling with slipping. Following the cementation, the samples' hardened layer thickness was 1.2 mm; on nitriding, the thickness of the hardened layer was 0.25 mm. The tests were carried out using an acoustic emission method, which is extremely sensitive when registering the transition of tribosystems' operation from the normal (mechanochemical) wear to the initial surface destruction of a fatigue nature.
The tests have shown that the average number of cycles before the initial destruction due to fatigue for the samples hardened by the Avinit nitriding technology is 1.82-time higher compared to the cementation-hardened samples. The depth of damage at the surface of the cemented samples could vary between 0.01 and 0.027 mm depending on the diameter of the damage. For the nitrided surfaces, the depth of damage did not exceed 0.003 mm.
The samples' resistance to the fatigue wear (destruction) was determined by tests based on 1,000,000 cycles at contact loads σmax=1,140 MPa, typical of medium-loaded surfaces. The test results demonstrated that the integrated multicyclic resistance to fatigue wear (destruction) of the samples, hardened by nitriding, is more than 10 times higher than that of the cementation-hardened samples.
The study reported here confirms the effectiveness of using the Avinit ion-plasma nitriding technology instead of cementing, to improve the contact strength of the parts' surfaces. At the same time, worth noting are the advantages of this technology to maintain the size and high quality of surface treatment, which eliminates the need to mechanically finish them after hardening.
{"title":"Comparative Analysis of the Fatigue Contact Strength of Surfaces Hardened by Cementation and the Ion Plasma Nitriding Аvinit N","authors":"A. V. Sagalovych, V. Popov, Vladislav Sagalovуch, S. Dudnik, Vladimir Bogoslavzev, N. Stadnichenko, A. Edinovych","doi":"10.15587/1729-4061.2020.217674","DOIUrl":"https://doi.org/10.15587/1729-4061.2020.217674","url":null,"abstract":"This paper reports comparative tribotechnical tests of surfaces, hardened by cementation and plasma nitriding Avinit N, for contact fatigue strength at friction in rolling with slipping. Following the cementation, the samples' hardened layer thickness was 1.2 mm; on nitriding, the thickness of the hardened layer was 0.25 mm. The tests were carried out using an acoustic emission method, which is extremely sensitive when registering the transition of tribosystems' operation from the normal (mechanochemical) wear to the initial surface destruction of a fatigue nature.<br><br>The tests have shown that the average number of cycles before the initial destruction due to fatigue for the samples hardened by the Avinit nitriding technology is 1.82-time higher compared to the cementation-hardened samples. The depth of damage at the surface of the cemented samples could vary between 0.01 and 0.027 mm depending on the diameter of the damage. For the nitrided surfaces, the depth of damage did not exceed 0.003 mm.<br><br>The samples' resistance to the fatigue wear (destruction) was determined by tests based on 1,000,000 cycles at contact loads σmax=1,140 MPa, typical of medium-loaded surfaces. The test results demonstrated that the integrated multicyclic resistance to fatigue wear (destruction) of the samples, hardened by nitriding, is more than 10 times higher than that of the cementation-hardened samples.<br><br>The study reported here confirms the effectiveness of using the Avinit ion-plasma nitriding technology instead of cementing, to improve the contact strength of the parts' surfaces. At the same time, worth noting are the advantages of this technology to maintain the size and high quality of surface treatment, which eliminates the need to mechanically finish them after hardening.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76079306","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 : 2020-12-22DOI: 10.15587/1729-4061.2020.217819
V. Kvasnytskyi, V. Korzhyk, V. Kvasnytskyi, H. Mialnitsa, C. Dong, T. Pryadko, M. Matviienko, Ye.A. Buturlia
One of the most promising structural materials in gas turbine engineering is the alloys based on an intermetallide, the type of Ni 3 Al, with an equiaxial and directional columnar structure. These materials make it possible to increase the working temperature of blades to 1,220 °C. The blades are made by the method of precise casting in a vacuum; in this case, it is necessary to technologically join the nozzle blades into blocks, to fix the signal holes in cooled blades, to correct casting defects. Welding by melting intermetallide materials, as well as other cast heat-resistant nickel alloys (HNA), does not yield positive results. Therefore, various brazing techniques are used such as TLP-Bonding (Transient Liquid Phase Bonding). Filler metals' melting point is lower than that of the main metal. The key issue related to the technology of brazing HNA, including the design of appropriate filler metals, is the improvement of the physical-mechanical and operational properties of brazed joints. This paper reports the established rational doping of a filler metal base, as well as depressants, the critical temperatures and surface properties of filler metals, their chemical composition, the structure and properties of brazed joints, the mode parameters, and brazing technology. To improve the stability of the structure and the high-temperature strength of the brazed joints, the filler metal was alloyed with rhenium and tantalum. Mechanical tests of brazed joints at 900 °C were conducted in Ukraine; at a temperature of 1,100 °C ‒ in the People's Republic of China. The test results showed that the short-term strength of alloy compounds with an equiaxial structure based on the Ni 3 Al-type intermetallide at 1,100 °C is 0.98 of the strength of the main metal. The long-lasting strength at the same temperature meets the requirements for the strength of the main metal
{"title":"Designing Brazing Filler Metal for Heat-Resistant Alloys Based on NI 3AL Intermetallide","authors":"V. Kvasnytskyi, V. Korzhyk, V. Kvasnytskyi, H. Mialnitsa, C. Dong, T. Pryadko, M. Matviienko, Ye.A. Buturlia","doi":"10.15587/1729-4061.2020.217819","DOIUrl":"https://doi.org/10.15587/1729-4061.2020.217819","url":null,"abstract":"One of the most promising structural materials in gas turbine engineering is the alloys based on an intermetallide, the type of Ni 3 Al, with an equiaxial and directional columnar structure. These materials make it possible to increase the working temperature of blades to 1,220 °C. The blades are made by the method of precise casting in a vacuum; in this case, it is necessary to technologically join the nozzle blades into blocks, to fix the signal holes in cooled blades, to correct casting defects. Welding by melting intermetallide materials, as well as other cast heat-resistant nickel alloys (HNA), does not yield positive results. Therefore, various brazing techniques are used such as TLP-Bonding (Transient Liquid Phase Bonding). Filler metals' melting point is lower than that of the main metal. The key issue related to the technology of brazing HNA, including the design of appropriate filler metals, is the improvement of the physical-mechanical and operational properties of brazed joints. This paper reports the established rational doping of a filler metal base, as well as depressants, the critical temperatures and surface properties of filler metals, their chemical composition, the structure and properties of brazed joints, the mode parameters, and brazing technology. To improve the stability of the structure and the high-temperature strength of the brazed joints, the filler metal was alloyed with rhenium and tantalum. Mechanical tests of brazed joints at 900 °C were conducted in Ukraine; at a temperature of 1,100 °C ‒ in the People's Republic of China. The test results showed that the short-term strength of alloy compounds with an equiaxial structure based on the Ni 3 Al-type intermetallide at 1,100 °C is 0.98 of the strength of the main metal. The long-lasting strength at the same temperature meets the requirements for the strength of the main metal","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"14 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90419994","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}
Progress in molecular electronics (ME) is largely based on improved understanding of the properties of single molecules (SM) trapped for seconds or longer to enable their detailed characterization. We present a plasmon-supported break-junction (PBJ) platform to significantly increase the lifetime of SM junctions of 1,4-benzendithiol (BDT) without the need for chemical modification of molecule or electrode. Moderate far-field power densities of ca. 11 mW/µm2 lead to a >10-fold increase in minimum lifetime compared to laser-OFF conditions. The nearfield trapping efficiency is twice as large for bridge-site contact compared to hollow-site geometry, which can be attributed to the difference in polarizability. Current measurements and tip-enhanced Raman spectra confirm that native structure and contact geometry of BDT are preserved during the PBJ experiment. By providing a non-invasive pathway to increase short lifetimes of SM junctions, PBJ is a valuable approach for ME, paving the way for improved SM sensing and recognition platforms.
{"title":"Nearfield Trapping Increases Lifetime of Single-Molecule Junction by One Order of Magnitude","authors":"Albert C. Aragonès, Katrin F. Domke","doi":"10.2139/ssrn.3751804","DOIUrl":"https://doi.org/10.2139/ssrn.3751804","url":null,"abstract":"\u0000 Progress in molecular electronics (ME) is largely based on improved understanding of the properties of single molecules (SM) trapped for seconds or longer to enable their detailed characterization. We present a plasmon-supported break-junction (PBJ) platform to significantly increase the lifetime of SM junctions of 1,4-benzendithiol (BDT) without the need for chemical modification of molecule or electrode. Moderate far-field power densities of ca. 11 mW/µm2 lead to a >10-fold increase in minimum lifetime compared to laser-OFF conditions. The nearfield trapping efficiency is twice as large for bridge-site contact compared to hollow-site geometry, which can be attributed to the difference in polarizability. Current measurements and tip-enhanced Raman spectra confirm that native structure and contact geometry of BDT are preserved during the PBJ experiment. By providing a non-invasive pathway to increase short lifetimes of SM junctions, PBJ is a valuable approach for ME, paving the way for improved SM sensing and recognition platforms.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"86 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90813597","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 : 2020-12-11DOI: 10.15587/1729-4061.2020.216610
P. Tretiakov, A. Toporov, O. Aleksieieva, O. Kostina, Viacheslav Borovlov
Operating conditions of thermal units for processing raw materials predetermine defects in refractory elements resulting in their gradual accumulation, which leads to a change in technical condition. A large number of defects, their development, and the achievement of critical values lead to difficulties in modeling the physical processes of changing the technical condition of refractory elements.This study has investigated the mechanism of the occurrence, development, and accumulation of defects in refractory elements, as well as the processes of cumulative accumulation of damages; a probability model of their degradation has been constructed. The model was built using Markov chains; it describes the sequences of change in the states of refractory element damage and the probability of transitions between these states. Based on the statistical data about a change in the state of damage, the model makes it possible to assess the probability of a defect reaching the critical condition following the predefined number of load cycles. A special feature of the model is the possibility of its application to individual defects, as well as to refractory elements on which defects occur and develop, as well as to assemblies where such refractory elements are installed.The main patterns of change in the technical condition of refractory elements of coke ovens have been established: the distribution of cracks of a certain length according to the number of coke oven output cycles; the probability of the occurrence of a crack of a critical length at a certain point during operation; the dependence of the probability of a refractory element failure on the predefined number of coke oven output cycles.Based on the modeling results, it has been proposed, in order to prevent the degradation of refractory elements, to strengthen the structure of the surface layer of the refractory element by cold gas-dynamic spraying, to arrange laying elements that would stop the evolution of defects, and to make up schedules of hot repairs based on the time when the defects may reach critical values, determined during modeling
{"title":"Revealing the Patterns of Change in the Technical Condition of Refractory Elements in Thermal Units During Operation","authors":"P. Tretiakov, A. Toporov, O. Aleksieieva, O. Kostina, Viacheslav Borovlov","doi":"10.15587/1729-4061.2020.216610","DOIUrl":"https://doi.org/10.15587/1729-4061.2020.216610","url":null,"abstract":"Operating conditions of thermal units for processing raw materials predetermine defects in refractory elements resulting in their gradual accumulation, which leads to a change in technical condition. A large number of defects, their development, and the achievement of critical values lead to difficulties in modeling the physical processes of changing the technical condition of refractory elements.This study has investigated the mechanism of the occurrence, development, and accumulation of defects in refractory elements, as well as the processes of cumulative accumulation of damages; a probability model of their degradation has been constructed. The model was built using Markov chains; it describes the sequences of change in the states of refractory element damage and the probability of transitions between these states. Based on the statistical data about a change in the state of damage, the model makes it possible to assess the probability of a defect reaching the critical condition following the predefined number of load cycles. A special feature of the model is the possibility of its application to individual defects, as well as to refractory elements on which defects occur and develop, as well as to assemblies where such refractory elements are installed.The main patterns of change in the technical condition of refractory elements of coke ovens have been established: the distribution of cracks of a certain length according to the number of coke oven output cycles; the probability of the occurrence of a crack of a critical length at a certain point during operation; the dependence of the probability of a refractory element failure on the predefined number of coke oven output cycles.Based on the modeling results, it has been proposed, in order to prevent the degradation of refractory elements, to strengthen the structure of the surface layer of the refractory element by cold gas-dynamic spraying, to arrange laying elements that would stop the evolution of defects, and to make up schedules of hot repairs based on the time when the defects may reach critical values, determined during modeling","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"475 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79634455","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}
Tingkun Liu, M. Olszta, B. Gwalani, Changyong Park, S. Mathaudhu, A. Devaraj
Abstract Non-hydrostatic compression of materials using a diamond anvil cell (DAC) can transform the equilibrium microstructure of an alloy to novel, potentially metastable states. In this study, in situ synchrotron X-ray diffraction (XRD) during compression up to 24 GPa and subsequent ex-situ, high resolution analytical electron microscopy (AEM) after decompression of an Al-Si alloy provided insight into the crystallographic changes during the compression as well as microstructural refinement, and defect structures caused by such a high pressure compression-decompression process. Pressure resolved in-situ synchrotron XRD was used to detail the phase transformation pathway of the eutectic Si phase in Al-Si alloy, from Si-I → Si-XI → Si-V during compression, and a final transformation predominantly to Si-III after decompression. Using scanning and transmission electron microscopy (S/TEM), site specific analysis of the alloy immediately underneath the anvil contact surface demonstrated a highly complex microstructure. A narrow region of thick amorphous Al oxide interspersed with nanocrystalline grains was found at the top surface. Underneath this Al oxide, while the majority of the eutectic Si was transformed into highly-deformed, polycrystalline (PC) Si-III, a complex intermediate layer was discovered at the interface between Al and Si, comprised of a small fraction of Al nanocrystals and a majority of nanocrystalline Si-I. This combination of pressure resolved in-situ synchrotron XRD coupled with subsequent high resolution, electron microscopy resolved the phase transformation as well as non-equilibrium microstructures in a metallic alloy induced by a non-hydrostatic high pressure compression followed by decompression.
{"title":"Phase Transformations, Microstructural Refinement and Defect Evolution Mechanisms in Al-Si Alloys Under Non-Hydrostatic Diamond Anvil Cell Compression","authors":"Tingkun Liu, M. Olszta, B. Gwalani, Changyong Park, S. Mathaudhu, A. Devaraj","doi":"10.2139/ssrn.3746796","DOIUrl":"https://doi.org/10.2139/ssrn.3746796","url":null,"abstract":"Abstract Non-hydrostatic compression of materials using a diamond anvil cell (DAC) can transform the equilibrium microstructure of an alloy to novel, potentially metastable states. In this study, in situ synchrotron X-ray diffraction (XRD) during compression up to 24 GPa and subsequent ex-situ, high resolution analytical electron microscopy (AEM) after decompression of an Al-Si alloy provided insight into the crystallographic changes during the compression as well as microstructural refinement, and defect structures caused by such a high pressure compression-decompression process. Pressure resolved in-situ synchrotron XRD was used to detail the phase transformation pathway of the eutectic Si phase in Al-Si alloy, from Si-I → Si-XI → Si-V during compression, and a final transformation predominantly to Si-III after decompression. Using scanning and transmission electron microscopy (S/TEM), site specific analysis of the alloy immediately underneath the anvil contact surface demonstrated a highly complex microstructure. A narrow region of thick amorphous Al oxide interspersed with nanocrystalline grains was found at the top surface. Underneath this Al oxide, while the majority of the eutectic Si was transformed into highly-deformed, polycrystalline (PC) Si-III, a complex intermediate layer was discovered at the interface between Al and Si, comprised of a small fraction of Al nanocrystals and a majority of nanocrystalline Si-I. This combination of pressure resolved in-situ synchrotron XRD coupled with subsequent high resolution, electron microscopy resolved the phase transformation as well as non-equilibrium microstructures in a metallic alloy induced by a non-hydrostatic high pressure compression followed by decompression.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"71 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83859310","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}
Jan Bartsch, T. Dehling, F. Lauf, S. Meister, A. Sunyaev
When using today's internet services and platform ecosystems, data of consumers is often harvested and shared without their consent; that is, consumers seized to be sovereigns of their own data. Due to the rapid and abundant nature of interactions in today's platform ecosystems, manual consent management is impracticable. To support development of semi-automated solutions for this problem, we investigated the use of policy definition languages as machine-readable and enforceable mechanism to re-establish data sovereignty for consumers. Based on an expert literature review, we develop a framework of the chances and challenges of leveraging policy definition languages as central building blocks for data sovereignty in platform ecosystems.
{"title":"Let the Computer Say NO! The Neglected Potential of Policy Definition Languages for Data Sovereignty","authors":"Jan Bartsch, T. Dehling, F. Lauf, S. Meister, A. Sunyaev","doi":"10.2139/ssrn.3646415","DOIUrl":"https://doi.org/10.2139/ssrn.3646415","url":null,"abstract":"When using today's internet services and platform ecosystems, data of consumers is often harvested and shared without their consent; that is, consumers seized to be sovereigns of their own data. Due to the rapid and abundant nature of interactions in today's platform ecosystems, manual consent management is impracticable. To support development of semi-automated solutions for this problem, we investigated the use of policy definition languages as machine-readable and enforceable mechanism to re-establish data sovereignty for consumers. Based on an expert literature review, we develop a framework of the chances and challenges of leveraging policy definition languages as central building blocks for data sovereignty in platform ecosystems.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"32 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73691566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Philadelphia & Reading was conceived to transport anthracite coal from the mining regions of Pennsylvania to the tidewater at Philadelphia. It built its roads and other system infrastructure during one of the worst economic depressions in U.S. history (the Panic of 1837, Crisis of 1839, and Collapse of 1842) by incurring massive amounts of indebtedness, which was in default for nonpayment of interest by 1842 when, teetering on bankruptcy, the P&R commenced operations. The P&R needed locomotives to generate revenue but had no cash to expend on engine purchases. In 1843 Locks & Canals agreed to build twelve engines for the P&R on a deferred payment basis. Despite its critical need for the engines, and rather curiously, in 1844 the P&R sold one of the precious engines (the twelfth engine), which was only fifteenth months of age. More perplexing, the engine was sold to the Central Railroad of Michigan, which was also in diminished financial circumstances, unable to pay cash for the engines, and in the process of being sold by Michigan.
The twelve engines are given passing mention in the literature. Some railroad historians, even those focusing on P&R engines, ignore them completely. The failure to explore the sale of the twelfth engine and the superficial treatment given all twelve engines in the literature are a bit surprising because they were among the first locomotives purchased by the P&R as it became operational and because the financing arrangements for their sale to the P&R were critical first steps in the developmental lineage of the equipment financing structure that has predominated continuously from the mid-1800s to the present.
This paper is one of two exploring a story not previously told: sale of the twelfth engine. This paper focuses on identification of the twelfth engine and its fate. The companion paper focuses on related questions. From the perspectives of the P&R and the Central Railroad, why was the engine sold and purchased?
{"title":"The Twelfth Engine: Tracks of the Mohegan","authors":"Michael J. T. McMillen","doi":"10.2139/ssrn.3454171","DOIUrl":"https://doi.org/10.2139/ssrn.3454171","url":null,"abstract":"The Philadelphia & Reading was conceived to transport anthracite coal from the mining regions of Pennsylvania to the tidewater at Philadelphia. It built its roads and other system infrastructure during one of the worst economic depressions in U.S. history (the Panic of 1837, Crisis of 1839, and Collapse of 1842) by incurring massive amounts of indebtedness, which was in default for nonpayment of interest by 1842 when, teetering on bankruptcy, the P&R commenced operations. The P&R needed locomotives to generate revenue but had no cash to expend on engine purchases. In 1843 Locks & Canals agreed to build twelve engines for the P&R on a deferred payment basis. Despite its critical need for the engines, and rather curiously, in 1844 the P&R sold one of the precious engines (the twelfth engine), which was only fifteenth months of age. More perplexing, the engine was sold to the Central Railroad of Michigan, which was also in diminished financial circumstances, unable to pay cash for the engines, and in the process of being sold by Michigan. <br><br>The twelve engines are given passing mention in the literature. Some railroad historians, even those focusing on P&R engines, ignore them completely. The failure to explore the sale of the twelfth engine and the superficial treatment given all twelve engines in the literature are a bit surprising because they were among the first locomotives purchased by the P&R as it became operational and because the financing arrangements for their sale to the P&R were critical first steps in the developmental lineage of the equipment financing structure that has predominated continuously from the mid-1800s to the present.<br><br>This paper is one of two exploring a story not previously told: sale of the twelfth engine. This paper focuses on identification of the twelfth engine and its fate. The companion paper focuses on related questions. From the perspectives of the P&R and the Central Railroad, why was the engine sold and purchased?","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"173 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91445561","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 : 2020-12-09DOI: 10.15587/1729-4061.2020.216754
O. Zaichuk, Аleksandra Amelina, Y. Hordieiev, Y. Kalishenko, N. Sribniak, S. Halushka, D. Borodai, A. Borodai
To create heat-resistant structural materials capable of operating at high temperatures (up to 1,400 °C), glass crystalline materials based on the SrO–Al 2 O 3 –SiO 2 system are promising. This paperreports the results of studying strontium-anorthite ceramics modified with boron-containing glass of the spodumene composition. It was established that in order to achieve a set of high physical and technical indicators of ceramics at reduced firing temperatures (1,200‒1,300 °C), it is necessary to introduce glass in the amount of 20‒30 % by weight. In this case, densely baked materials with low TCLE values were obtained (32.0–33.4)·10 -7 degrees -7 , which predetermine their high thermal resistance (not lower than 850 °C). The principal crystalline phase of the examined ceramics is a monoclinic modification of strontium anorthite that mainly forms its microstructure. The strontium anorthite crystals measuring from 1‒2 µm to 3–4 µm are tightly connected via thin layers of the residual glass phase. In the glass phase, the β-spodumene crystals the size of 0.1–0.3 µm are evenly distributed. The observed microstructure features of ceramics determine zero values of water absorption and open porosity, as well as high density values (2.40–2.50 g/cm 3 ) and mechanical compression strength values (237–246 MPa). The dense microstructure also makes it possible to achieve high dielectric indicators (e=4.4–4.8; tgδ=0.005–0.007) in an ultra-high-frequency electromagnetic field. Therefore, the designed materials are promising as radio-translucent materials, including structural ones. In addition, the enrichment of the residual glass phase with the refractory components of the SAS system in the process of firing the examined ceramics predetermines its increased resistance to high-temperature heating during operation
{"title":"Patterns in the Synthesis Processes, the Microstructure and Properties of Strontium Anorthite Ceramics Modified by Glass of Spodumene Composition","authors":"O. Zaichuk, Аleksandra Amelina, Y. Hordieiev, Y. Kalishenko, N. Sribniak, S. Halushka, D. Borodai, A. Borodai","doi":"10.15587/1729-4061.2020.216754","DOIUrl":"https://doi.org/10.15587/1729-4061.2020.216754","url":null,"abstract":"To create heat-resistant structural materials capable of operating at high temperatures (up to 1,400 °C), glass crystalline materials based on the SrO–Al 2 O 3 –SiO 2 system are promising. This paperreports the results of studying strontium-anorthite ceramics modified with boron-containing glass of the spodumene composition. It was established that in order to achieve a set of high physical and technical indicators of ceramics at reduced firing temperatures (1,200‒1,300 °C), it is necessary to introduce glass in the amount of 20‒30 % by weight. In this case, densely baked materials with low TCLE values were obtained (32.0–33.4)·10 -7 degrees -7 , which predetermine their high thermal resistance (not lower than 850 °C). The principal crystalline phase of the examined ceramics is a monoclinic modification of strontium anorthite that mainly forms its microstructure. The strontium anorthite crystals measuring from 1‒2 µm to 3–4 µm are tightly connected via thin layers of the residual glass phase. In the glass phase, the β-spodumene crystals the size of 0.1–0.3 µm are evenly distributed. The observed microstructure features of ceramics determine zero values of water absorption and open porosity, as well as high density values (2.40–2.50 g/cm 3 ) and mechanical compression strength values (237–246 MPa). The dense microstructure also makes it possible to achieve high dielectric indicators (e=4.4–4.8; tgδ=0.005–0.007) in an ultra-high-frequency electromagnetic field. Therefore, the designed materials are promising as radio-translucent materials, including structural ones. In addition, the enrichment of the residual glass phase with the refractory components of the SAS system in the process of firing the examined ceramics predetermines its increased resistance to high-temperature heating during operation","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"173 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79573855","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}
Adsorption is a widely used technique for wastewater remediation. The process is effective and economical for the removal of various pollutants from wastewater, including dyes. Moreover, Besides commercial activated carbon, different low-cost materials such as agricultural and industrial wastes are now used as adsorbents. The present review focused on the removal of a teratogenic and carcinogenic dye, orange G (OG) via adsorption using several adsorbents, together with the experimental conditions and their adsorption capacities. Based on the information compiled, various adsorbents have shown promising potential for OG removal.
{"title":"Removal of Orange G Dye from Aqueous Solution by Adsorption: A Short Review","authors":"S. Imam, Atika Muhammad, H. F. Babamale, Z. Zango","doi":"10.47277/jett/9(1)327","DOIUrl":"https://doi.org/10.47277/jett/9(1)327","url":null,"abstract":"Adsorption is a widely used technique for wastewater remediation. The process is effective and economical for the removal of various pollutants from wastewater, including dyes. Moreover, Besides commercial activated carbon, different low-cost materials such as agricultural and industrial wastes are now used as adsorbents. The present review focused on the removal of a teratogenic and carcinogenic dye, orange G (OG) via adsorption using several adsorbents, together with the experimental conditions and their adsorption capacities. Based on the information compiled, various adsorbents have shown promising potential for OG removal.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84156275","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}
Peng Zhang, K. Shi, J. Bian, Jinyu Zhang, Yong Peng, Gang Liu, A. Deschamps, Jun Sun
The natural aging (NA) response of a commercial Al-Zn-Mg alloy has been tracked to investigate the effects of solute clusters on its mechanical properties. It is observed that the increase of yield strength during NA is not accompanied by a degeneration of uniform elongation due to the simultaneously enhanced strain hardening ability. As a consequence, the Al-Zn-Mg alloy with dense solute clusters shows a comparative yield strength, better strain hardening ability and ductility relative to its artificially aged counterparts containing precipitates. This positive effect of solute clusters on strain hardening has been systematically studied by tracing the microstructure evolution during deformation through the synchrotron X-ray diffraction and atom probe tomography techniques. We found that the dislocation multiplication dominates over the entire deformation until failure in NA alloys; however, no effect of solute clusters on the dislocation density evolution can be identified. On the other hand, solute clusters themselves dramatically evolve, showing a dissolution-to-coarsening transition during deformation, which can be understood on the basis of a kinetic model. The experimental phenomena strongly suggest that the dislocation storage and strain-induced evolution of solute clusters are far from adequate to account for the observed high strain hardening rate, and contribution from other possible mechanisms are estimated in a semi-quantitative manner.
{"title":"Solute Cluster Evolution During Deformation and High Strain Hardening Capability in Naturally Aged Al-Zn-Mg Alloy","authors":"Peng Zhang, K. Shi, J. Bian, Jinyu Zhang, Yong Peng, Gang Liu, A. Deschamps, Jun Sun","doi":"10.2139/ssrn.3737324","DOIUrl":"https://doi.org/10.2139/ssrn.3737324","url":null,"abstract":"The natural aging (NA) response of a commercial Al-Zn-Mg alloy has been tracked to investigate the effects of solute clusters on its mechanical properties. It is observed that the increase of yield strength during NA is not accompanied by a degeneration of uniform elongation due to the simultaneously enhanced strain hardening ability. As a consequence, the Al-Zn-Mg alloy with dense solute clusters shows a comparative yield strength, better strain hardening ability and ductility relative to its artificially aged counterparts containing precipitates. This positive effect of solute clusters on strain hardening has been systematically studied by tracing the microstructure evolution during deformation through the synchrotron X-ray diffraction and atom probe tomography techniques. We found that the dislocation multiplication dominates over the entire deformation until failure in NA alloys; however, no effect of solute clusters on the dislocation density evolution can be identified. On the other hand, solute clusters themselves dramatically evolve, showing a dissolution-to-coarsening transition during deformation, which can be understood on the basis of a kinetic model. The experimental phenomena strongly suggest that the dislocation storage and strain-induced evolution of solute clusters are far from adequate to account for the observed high strain hardening rate, and contribution from other possible mechanisms are estimated in a semi-quantitative manner.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78944518","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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