Although gravity is the weakest of the four fundamental forces that keep the universe from flying apart, it is the only one that we can directly perceive. Everything on the earth that has mass experiences it, as the force of gravity pulls it toward the iron core at the center of our planet. Weight and mass are connected by gravity. The world standard unit of measurement of weight is the kilogram (kg). Even in the USA, where imperial measurements of weight, distance, and volume are still in wide public use, those units are referenced to the metric SI system. So a pound (of weight) in the USA is not defined by another imperial.
{"title":"Arduino Weighing Machine Using Load Cell and HX711 Module","authors":"Varshitha Itikala","doi":"10.2139/ssrn.3918720","DOIUrl":"https://doi.org/10.2139/ssrn.3918720","url":null,"abstract":"Although gravity is the weakest of the four fundamental forces that keep the universe from flying apart, it is the only one that we can directly perceive. Everything on the earth that has mass experiences it, as the force of gravity pulls it toward the iron core at the center of our planet. Weight and mass are connected by gravity. The world standard unit of measurement of weight is the kilogram (kg). Even in the USA, where imperial measurements of weight, distance, and volume are still in wide public use, those units are referenced to the metric SI system. So a pound (of weight) in the USA is not defined by another imperial.","PeriodicalId":10592,"journal":{"name":"Computational & Theoretical Chemistry eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91437598","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}
Chao Jiang, Yongfeng Zhang, L. Aagesen, A. Jokisaari, Cheng Sun, J. Gan
Abstract Understanding the interactions of noble gases with metals is of fundamental importance for the design of radiation-resistant structural materials for fission and fusion nuclear reactors. Here we present a unified theory for describing the energetics of He, Ne, Ar, and Kr bubbles in bcc metals in group 5B (V, Nb, Ta), 6B (Cr, Mo, W) and 8B (Fe). Our predictive analytical model is based on the effective-medium and isotropic elasticity theories, and is parameterized using density functional theory (DFT) calculations of small gas-vacancy clusters. By performing kinetic Monte Carlo (KMC) simulations driven by our analytical model, we have predicted the lifetimes of noble gas bubbles and their coarsening by Ostwald ripening. Our most notable finding is the exceptionally higher thermal stability of Ne, Ar and Kr bubbles than He bubbles in bcc metals, conferring them outstanding resistance to Ostwald ripening. The physical origin of the unexpected stability of bubbles formed by large noble gas atoms has been further elucidated. Our theoretical finding is consistent with the experimental observation of He gas bubble superlattice (GBS) coarsening under thermal annealing, and provides new insights on the exceptional stability of fission GBS in bcc U-Mo up to a high homologous temperature of 0.78. The present calculated results also compare favorably with the existing thermal helium desorption spectrometry experiments in the literature.
{"title":"Noble Gas Bubbles in Bcc Metals: Ab Initio-Based Theory and Kinetic Monte Carlo Modeling","authors":"Chao Jiang, Yongfeng Zhang, L. Aagesen, A. Jokisaari, Cheng Sun, J. Gan","doi":"10.2139/ssrn.3784442","DOIUrl":"https://doi.org/10.2139/ssrn.3784442","url":null,"abstract":"Abstract Understanding the interactions of noble gases with metals is of fundamental importance for the design of radiation-resistant structural materials for fission and fusion nuclear reactors. Here we present a unified theory for describing the energetics of He, Ne, Ar, and Kr bubbles in bcc metals in group 5B (V, Nb, Ta), 6B (Cr, Mo, W) and 8B (Fe). Our predictive analytical model is based on the effective-medium and isotropic elasticity theories, and is parameterized using density functional theory (DFT) calculations of small gas-vacancy clusters. By performing kinetic Monte Carlo (KMC) simulations driven by our analytical model, we have predicted the lifetimes of noble gas bubbles and their coarsening by Ostwald ripening. Our most notable finding is the exceptionally higher thermal stability of Ne, Ar and Kr bubbles than He bubbles in bcc metals, conferring them outstanding resistance to Ostwald ripening. The physical origin of the unexpected stability of bubbles formed by large noble gas atoms has been further elucidated. Our theoretical finding is consistent with the experimental observation of He gas bubble superlattice (GBS) coarsening under thermal annealing, and provides new insights on the exceptional stability of fission GBS in bcc U-Mo up to a high homologous temperature of 0.78. The present calculated results also compare favorably with the existing thermal helium desorption spectrometry experiments in the literature.","PeriodicalId":10592,"journal":{"name":"Computational & Theoretical Chemistry eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74302923","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}
Hao Yu, Jialing Li, Songsong Li, Jeffrey S. Moore, Charles M. Schroeder
Charge transport through π-conjugated molecules plays an essential role in biochemical redox processes and energy storage applications. In this work, we show that molecular charge transport is greatly enhanced upon dimerization of certain pyridinium molecules in the cavity of a synthetic host (cucurbit[8]uril, CB[8]). Stable, homoternary complexes are formed between pyridinium molecules and CB[8] with high binding affinity, resulting in an offset stacked geometry of two pyridiniums inside the host cavity. The charge transport properties of free and dimerized pyridiniums are characterized using a scanning tunneling microscope-break junction (STM-BJ) technique. Remarkably, our results show that π-stacked methylated pyridinium dimers exhibit a 10-fold increase in molecular conductance compared to isolated, single pyridinium molecules. Control experiments using CB[8] homologues show that the synthetic host primarily serves to facilitate dimer formation and plays a minimal role on molecular conductance. Molecular modeling is used to determine transmission functions for molecular junctions using the non-equilibrium Green’s function formalism, with simulations showing good agreement with experimental results. Density functional theory (DFT) reveals that the closely stacked pyridinium dimer has a reduced energy gap and favorable orbital energy alignment with gold electrodes, thereby resulting in enhanced molecular conductance. Overall, this work demonstrates that supramolecular assembly provides a useful approach to understand intermolecular charge transport in π-stacked molecules.
{"title":"Single-Molecule Charge Transport in Discrete, π-Stacked Pyridinium Dimers","authors":"Hao Yu, Jialing Li, Songsong Li, Jeffrey S. Moore, Charles M. Schroeder","doi":"10.2139/ssrn.3809994","DOIUrl":"https://doi.org/10.2139/ssrn.3809994","url":null,"abstract":"Charge transport through π-conjugated molecules plays an essential role in biochemical redox processes and energy storage applications. In this work, we show that molecular charge transport is greatly enhanced upon dimerization of certain pyridinium molecules in the cavity of a synthetic host (cucurbit[8]uril, CB[8]). Stable, homoternary complexes are formed between pyridinium molecules and CB[8] with high binding affinity, resulting in an offset stacked geometry of two pyridiniums inside the host cavity. The charge transport properties of free and dimerized pyridiniums are characterized using a scanning tunneling microscope-break junction (STM-BJ) technique. Remarkably, our results show that π-stacked methylated pyridinium dimers exhibit a 10-fold increase in molecular conductance compared to isolated, single pyridinium molecules. Control experiments using CB[8] homologues show that the synthetic host primarily serves to facilitate dimer formation and plays a minimal role on molecular conductance. Molecular modeling is used to determine transmission functions for molecular junctions using the non-equilibrium Green’s function formalism, with simulations showing good agreement with experimental results. Density functional theory (DFT) reveals that the closely stacked pyridinium dimer has a reduced energy gap and favorable orbital energy alignment with gold electrodes, thereby resulting in enhanced molecular conductance. Overall, this work demonstrates that supramolecular assembly provides a useful approach to understand intermolecular charge transport in π-stacked molecules.","PeriodicalId":10592,"journal":{"name":"Computational & Theoretical Chemistry eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87656706","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. Ontiveros, Ivan Plaza, J. Calero, A. Moleon, J. Ibáñez
Landslides on the flanks of stratovolcanoes can significantly modify the structure of the volcano. Macroscopic factors that determine the stability of volcanic deposits are well understood, but the microscopic interactions between particles and their impact on deposit cohesion remain poorly understood. Deposit cohesion is related to the energy of interaction between particles, and its calculation depends on the surficial properties of the eruptive materials. The purpose of this study was to perform a preliminary comparative analysis of the surficial properties of volcanic materials from various tectonic settings, including electrical (zeta potential) and thermodynamic (surface free energy) components and to calculate the total interaction energy between particles under different environmental conditions. We analyzed eruptive materials from six active volcanoes (El Hierro, Pico Do Fogo, Vulcano, Stromboli, Mt. Etna, and Deception Island). The results show that deposit cohesion varies among volcanoes, and changes drastically with the pH of the medium. Among the volcanic systems investigated, El Hierro (pH = 3) has the most cohesive materials, while Mt. Etna (pH = 8) has the least cohesive materials. Our results suggest that microscopic electrical and thermodynamic properties play a role in the stability of volcanic deposits, and confirm the need for a greater research focus in this area.
层状火山两侧的滑坡可以显著地改变火山的结构。决定火山沉积物稳定性的宏观因素已经被很好地理解，但微观颗粒之间的相互作用及其对沉积物粘聚性的影响仍然知之甚少。沉积内聚力与粒子间相互作用的能量有关，其计算取决于喷发物质的表面性质。本研究的目的是对不同构造环境下火山物质的表面特性进行初步比较分析，包括电学(zeta电位)和热力学(表面自由能)分量，并计算不同环境条件下粒子之间的总相互作用能。我们分析了6座活火山的喷发物质(El耶罗火山、Pico Do Fogo火山、Vulcano火山、Stromboli火山、埃特纳火山和欺骗岛)。结果表明，不同火山的沉积物黏结性不同，并随介质pH值的变化而剧烈变化。在所研究的火山系统中，El耶罗火山(pH = 3)的粘性物质最多，而Mt. Etna火山(pH = 8)的粘性物质最少。我们的研究结果表明，微观电学和热力学性质在火山沉积物的稳定性中起着重要作用，并证实了这一领域需要更多的研究重点。
{"title":"High Variability of Surface Free Energy and Zeta Potential of Volcanic Particles: Implications for Deposit Stability","authors":"A. Ontiveros, Ivan Plaza, J. Calero, A. Moleon, J. Ibáñez","doi":"10.2139/ssrn.3927597","DOIUrl":"https://doi.org/10.2139/ssrn.3927597","url":null,"abstract":"Landslides on the flanks of stratovolcanoes can significantly modify the structure of the volcano. Macroscopic factors that determine the stability of volcanic deposits are well understood, but the microscopic interactions between particles and their impact on deposit cohesion remain poorly understood. Deposit cohesion is related to the energy of interaction between particles, and its calculation depends on the surficial properties of the eruptive materials. The purpose of this study was to perform a preliminary comparative analysis of the surficial properties of volcanic materials from various tectonic settings, including electrical (zeta potential) and thermodynamic (surface free energy) components and to calculate the total interaction energy between particles under different environmental conditions. We analyzed eruptive materials from six active volcanoes (El Hierro, Pico Do Fogo, Vulcano, Stromboli, Mt. Etna, and Deception Island). The results show that deposit cohesion varies among volcanoes, and changes drastically with the pH of the medium. Among the volcanic systems investigated, El Hierro (pH = 3) has the most cohesive materials, while Mt. Etna (pH = 8) has the least cohesive materials. Our results suggest that microscopic electrical and thermodynamic properties play a role in the stability of volcanic deposits, and confirm the need for a greater research focus in this area.","PeriodicalId":10592,"journal":{"name":"Computational & Theoretical Chemistry eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77092946","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}
Xuning Li, Chang Chang, Sung-Fu Hung, Ying-Rui Lu, Weizheng Cai, A. Rykov, S. Miao, S. Xi, Hongbin Yang, Zehua Hu, Junhu Wang, Jiyong Zhao, E. Alp, W. Xu, T. Chan, Hao Ming Chen, Q. Xiong, Hai Xiao, Yanqiang Huang, Jun Li, Tao Zhang, Bin Liu
Summary The lack of model single-atom catalysts (SACs) and atomic-resolution operando spectroscopic techniques greatly limits our comprehension of the nature of catalysis. Herein, based on the designed model single-Fe-atom catalysts with well-controlled microenvironments, we have explored the exact structure of catalytic centers and provided insights into a spin-crossover-involved mechanism for oxygen reduction reaction (ORR) using operando Raman, X-ray absorption spectroscopies, and the developed operando 57Fe Mossbauer spectroscopy. In combination with theoretical studies, the N-FeN4C10 moiety is evidenced as a more active site for ORR. Moreover, the potential-relevant dynamic cycles of both geometric structure and electronic configuration of reactive single-Fe-atom moieties are evidenced via capturing the peroxido (∗O2−) and hydroxyl (∗OH−) intermediates under in situ ORR conditions. We anticipate that the integration of operando techniques and SACs in this work shall shed some light on the electronic-level insight into the catalytic centers and underlying reaction mechanism.
{"title":"Identification of the Electronic and Structural Dynamics of Catalytic Centers in Single-Fe-Atom Material","authors":"Xuning Li, Chang Chang, Sung-Fu Hung, Ying-Rui Lu, Weizheng Cai, A. Rykov, S. Miao, S. Xi, Hongbin Yang, Zehua Hu, Junhu Wang, Jiyong Zhao, E. Alp, W. Xu, T. Chan, Hao Ming Chen, Q. Xiong, Hai Xiao, Yanqiang Huang, Jun Li, Tao Zhang, Bin Liu","doi":"10.2139/ssrn.3713498","DOIUrl":"https://doi.org/10.2139/ssrn.3713498","url":null,"abstract":"Summary The lack of model single-atom catalysts (SACs) and atomic-resolution operando spectroscopic techniques greatly limits our comprehension of the nature of catalysis. Herein, based on the designed model single-Fe-atom catalysts with well-controlled microenvironments, we have explored the exact structure of catalytic centers and provided insights into a spin-crossover-involved mechanism for oxygen reduction reaction (ORR) using operando Raman, X-ray absorption spectroscopies, and the developed operando 57Fe Mossbauer spectroscopy. In combination with theoretical studies, the N-FeN4C10 moiety is evidenced as a more active site for ORR. Moreover, the potential-relevant dynamic cycles of both geometric structure and electronic configuration of reactive single-Fe-atom moieties are evidenced via capturing the peroxido (∗O2−) and hydroxyl (∗OH−) intermediates under in situ ORR conditions. We anticipate that the integration of operando techniques and SACs in this work shall shed some light on the electronic-level insight into the catalytic centers and underlying reaction mechanism.","PeriodicalId":10592,"journal":{"name":"Computational & Theoretical Chemistry eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79261725","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}
L. Tang, Z. J. Yang, T. Wen, K. Ho, M. Kramer, Caizhuang Wang
Molecular dynamics simulations using an interatomic potential developed by artificial neural network deep machine learning are performed to study the local structural order in Al90Tb10 metallic glass. We show that more than 80% of the Tb-centered clusters in Al90Tb10 glass have short-range order (SRO) with their 17 first coordination shell atoms stacked in a '3661' or '15551' sequence. Medium-range order (MRO) in Bergman-type packing extended out to the second and third coordination shells is also clearly observed. Analysis of the network formed by the '3661' and '15551' clusters show that ~82% of such SRO units share their faces or vertexes, while only ~6% of neighboring SRO pairs are interpenetrating. Such a network topology is consistent with the Bergman-type MRO around the Tb-centers. Moreover, crystal structure searches using genetic algorithm and the neural network interatomic potential reveal several low-energy metastable crystalline structures in the composition range close to Al90Tb10. Some of these crystalline structures have the '3661' SRO while others have the '15551' SRO. While the crystalline structures with the '3661' SRO also exhibit the MRO very similar to that observed in the glass, the ones with the '15551' SRO have very different atomic packing in the second and third shells around the Tb centers from that of the Bergman-type MRO observed in the glassy phase.
{"title":"Short- and Medium-Range Orders in Al 90Tb 10 Glass and Their Relation to the Structures of Competing Crystalline Phases","authors":"L. Tang, Z. J. Yang, T. Wen, K. Ho, M. Kramer, Caizhuang Wang","doi":"10.2139/ssrn.3692997","DOIUrl":"https://doi.org/10.2139/ssrn.3692997","url":null,"abstract":"Molecular dynamics simulations using an interatomic potential developed by artificial neural network deep machine learning are performed to study the local structural order in Al90Tb10 metallic glass. We show that more than 80% of the Tb-centered clusters in Al90Tb10 glass have short-range order (SRO) with their 17 first coordination shell atoms stacked in a '3661' or '15551' sequence. Medium-range order (MRO) in Bergman-type packing extended out to the second and third coordination shells is also clearly observed. Analysis of the network formed by the '3661' and '15551' clusters show that ~82% of such SRO units share their faces or vertexes, while only ~6% of neighboring SRO pairs are interpenetrating. Such a network topology is consistent with the Bergman-type MRO around the Tb-centers. Moreover, crystal structure searches using genetic algorithm and the neural network interatomic potential reveal several low-energy metastable crystalline structures in the composition range close to Al90Tb10. Some of these crystalline structures have the '3661' SRO while others have the '15551' SRO. While the crystalline structures with the '3661' SRO also exhibit the MRO very similar to that observed in the glass, the ones with the '15551' SRO have very different atomic packing in the second and third shells around the Tb centers from that of the Bergman-type MRO observed in the glassy phase.","PeriodicalId":10592,"journal":{"name":"Computational & Theoretical Chemistry eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83568604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In research laboratories and various industries, azo compounds are among the most effective and commonly used organic dyes. Throughout this research the interaction between human and bovine serum albumins with 5-(2-Thiazolylazo)-2,4,6-Triaminopyrimidine (TTP) was explored using methods of spectroscopy and analysis of molecular modeling. The fluorescence quenching results revealed that static and dynamic processes are the quenching mechanisms for human and bovine serum albumins, respectively. The results of the quenching experiment were used to measure thermodynamic parameters [[EQUATION]] which showed that the binding process that takes place spontaneously and revealed that human and bovine serum albumins are very firmly binding through hydrogen bonds, van der Waals forces interactions and electrostatic forces. Calculations of Fӧrster energy transfer, synchronous fluorescence spectroscopy and docking analysis showed TTP bindings in short distances to the Trp residues of human and bovine serum albumin molecules. Docking study showed that TTP molecule has four hydrogen bonds with HSA, two hydrogen bonds with BSA and several hydrophobic contacts with human and bovine serum albumins. FT-IR results showed that serum albumins interact with TTP molecule primarily through hydrophobic and hydrophilic interactions, and that the secondary structure of serum albumins is modified.
{"title":"Multi Technique Investigation on Binding Interaction between 5-(2-Thiazolylazo)-2,4,6-Triaminopyrimidine and Hsa and Bsa","authors":"H. Dezhampanah, Amineh mousazadeh moghaddam pour","doi":"10.2139/ssrn.3707243","DOIUrl":"https://doi.org/10.2139/ssrn.3707243","url":null,"abstract":"In research laboratories and various industries, azo compounds are among the most effective and commonly used organic dyes. Throughout this research the interaction between human and bovine serum albumins with 5-(2-Thiazolylazo)-2,4,6-Triaminopyrimidine (TTP) was explored using methods of spectroscopy and analysis of molecular modeling. The fluorescence quenching results revealed that static and dynamic processes are the quenching mechanisms for human and bovine serum albumins, respectively. The results of the quenching experiment were used to measure thermodynamic parameters [[EQUATION]] which showed that the binding process that takes place spontaneously and revealed that human and bovine serum albumins are very firmly binding through hydrogen bonds, van der Waals forces interactions and electrostatic forces. Calculations of Fӧrster energy transfer, synchronous fluorescence spectroscopy and docking analysis showed TTP bindings in short distances to the Trp residues of human and bovine serum albumin molecules. Docking study showed that TTP molecule has four hydrogen bonds with HSA, two hydrogen bonds with BSA and several hydrophobic contacts with human and bovine serum albumins. FT-IR results showed that serum albumins interact with TTP molecule primarily through hydrophobic and hydrophilic interactions, and that the secondary structure of serum albumins is modified.","PeriodicalId":10592,"journal":{"name":"Computational & Theoretical Chemistry eJournal","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75093218","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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