V. G. Bui, Thi Minh Tu Bui, Hwai Chyuan Ong, V. Bui, Thi Thanh Xuan Nguyen, A. Atabani, Le Hoang Phu Pham, A. Hoang
The smart control of the biogas-hydrogen engine is needed to improve the overall energy efficiency of the hybrid renewable energy system. The paper focuses on studying the optimal control parameters of the engine aiming to achieve the compromise between performance and pollutant emissions of the biogas-hydrogen engine. In neat biogas fueling mode, the optimal equivalence ratio changes from 1.05 to 1.01 as the CH4 composition in biogas increases from 60% to 80%. By adding 20% hydrogen into biogas, the optimal equivalence ratio practically reaches the stoichiometric value, despite the variation of CH4 concentration. At the same operating condition and hydrogen content, an increase of 10% CH4 in biogas leads to a decrease of 2°CA in the optimal advanced ignition angle. However, at a given engine speed and biogas composition, the optimal advanced ignition angle decreased by 3°CA when adding 10% hydrogen into biogas. The optimal ignition angle is independent of the load regime. Under optimal operating conditions, the addition of 20% hydrogen content into biogas is found to improve the indicated engine cycle work by 6%, to reduce CO and HC emissions by 5-10 times; however, it increases NOx emission by 10-15% compared to neat biogas fueling mode.
{"title":"Optimizing Operation Parameters of a Spark-Ignition Engine Fueled with Biogas-Hydrogen Blend in Hybrid Renewable Energy System Working on Solar and Biomass","authors":"V. G. Bui, Thi Minh Tu Bui, Hwai Chyuan Ong, V. Bui, Thi Thanh Xuan Nguyen, A. Atabani, Le Hoang Phu Pham, A. Hoang","doi":"10.2139/ssrn.3935493","DOIUrl":"https://doi.org/10.2139/ssrn.3935493","url":null,"abstract":"The smart control of the biogas-hydrogen engine is needed to improve the overall energy efficiency of the hybrid renewable energy system. The paper focuses on studying the optimal control parameters of the engine aiming to achieve the compromise between performance and pollutant emissions of the biogas-hydrogen engine. In neat biogas fueling mode, the optimal equivalence ratio changes from 1.05 to 1.01 as the CH4 composition in biogas increases from 60% to 80%. By adding 20% hydrogen into biogas, the optimal equivalence ratio practically reaches the stoichiometric value, despite the variation of CH4 concentration. At the same operating condition and hydrogen content, an increase of 10% CH4 in biogas leads to a decrease of 2°CA in the optimal advanced ignition angle. However, at a given engine speed and biogas composition, the optimal advanced ignition angle decreased by 3°CA when adding 10% hydrogen into biogas. The optimal ignition angle is independent of the load regime. Under optimal operating conditions, the addition of 20% hydrogen content into biogas is found to improve the indicated engine cycle work by 6%, to reduce CO and HC emissions by 5-10 times; however, it increases NOx emission by 10-15% compared to neat biogas fueling mode.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81462853","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 glass relaxation under ambient conditions is essential for understanding the nature of glass state, and has stimulated scientific and general public interests for centuries. However, owing to the extremely slow dynamics, experimental characterization of glass relaxation at ambient temperatures is quite challenging, and often takes several years. Here we report evident relaxation of metallic glasses at room temperature within the observation time of less one month when the feature size of glasses is reduced. The relaxation dynamics shows a size dependence similar to that on temperature, and an equivalence between size and temperature on affecting the relaxation dynamics is established. We also showed that a MG film with a feature size of ~ 10 nm at room temperature has a fast relaxation dynamics equivalent to that of a bulk MG near the glass transition temperature, indicating that the liquid-like behavior in glasses can be induced by size reduction.
{"title":"Evident Glass Relaxation at Room Temperature Manifested by Size Effect","authors":"B. Sun, W. Cao, Zijian Wang, B. Sun, Weihua Wang","doi":"10.2139/ssrn.3919729","DOIUrl":"https://doi.org/10.2139/ssrn.3919729","url":null,"abstract":"The glass relaxation under ambient conditions is essential for understanding the nature of glass state, and has stimulated scientific and general public interests for centuries. However, owing to the extremely slow dynamics, experimental characterization of glass relaxation at ambient temperatures is quite challenging, and often takes several years. Here we report evident relaxation of metallic glasses at room temperature within the observation time of less one month when the feature size of glasses is reduced. The relaxation dynamics shows a size dependence similar to that on temperature, and an equivalence between size and temperature on affecting the relaxation dynamics is established. We also showed that a MG film with a feature size of ~ 10 nm at room temperature has a fast relaxation dynamics equivalent to that of a bulk MG near the glass transition temperature, indicating that the liquid-like behavior in glasses can be induced by size reduction.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"97 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74481066","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 this paper, two model NiCrAlY/NiAlCoCrW coating/superalloy diffusion couples, cp0 and cp15, were prepared and subjected to annealing at 1173 K for 40 h under no stress and a uniaxial compressive stress of 15 MPa, respectively. No microstructural evolution occurred in cp0, while apparent interdiffusion zones and especially a number of TCP phases developed across the interface in cp15. The TCP precipitates, majorly consisting of Ni, Cr, Co and W, were identified as μ phase. Moreover, μ-TCP phase precipitated as small granular particles along the interface perpendicular to the loading axis, while as large needle-like ones on both coating and superalloy sides parallel to the loading direction. The formation of μ-TCP phase with complex morphologies at such early stage of interdiffusion process due to the coupled effect of compressive stress and ambient temperature may seriously reduce the creep lifetime of the coatings/superalloy system.
{"title":"Stress-Induced Formation of μ-TCP Phase During the Early-Stage Interdiffusion Process in the NiCrAlY/NiAlCoCrW Model Coating/Superalloy System at Ambient Temperature","authors":"Qin Li, Shiyao Chen, Yueheng Zhang, Chunming Deng, Lijun Zhang","doi":"10.2139/ssrn.3848996","DOIUrl":"https://doi.org/10.2139/ssrn.3848996","url":null,"abstract":"In this paper, two model NiCrAlY/NiAlCoCrW coating/superalloy diffusion couples, <b>cp0</b> and <b>cp15</b>, were prepared and subjected to annealing at 1173 K for 40 h under no stress and a uniaxial compressive stress of 15 MPa, respectively. No microstructural evolution occurred in <b>cp0</b>, while apparent interdiffusion zones and especially a number of TCP phases developed across the interface in <b>cp15</b>. The TCP precipitates, majorly consisting of Ni, Cr, Co and W, were identified as μ phase. Moreover, μ-TCP phase precipitated as small granular particles along the interface perpendicular to the loading axis, while as large needle-like ones on both coating and superalloy sides parallel to the loading direction. The formation of μ-TCP phase with complex morphologies at such early stage of interdiffusion process due to the coupled effect of compressive stress and ambient temperature may seriously reduce the creep lifetime of the coatings/superalloy system.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73267209","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 tensile mechanical behaviour of tetragonal zirconia micro/nano-fibers and beams were studied with a push-to-pull (PTP) device equipped in an in-situ nanoindenter. Polycrystalline and oligocrystalline micro/nano-fibers exhibited some degree of plastic strain before fracture with the tensile strength ranging from ~0.9 GPa to 1.4 GPa. Single-crystal beams generally experienced linear elastic deformation with tensile strength of ~2.1-3.4 GPa. No martensitic transformation induced shape memory strain was detected in the zirconia fibers and beams. Further variation of dopant concentration and crystal orientation was explored for single-crystalline beams and their significance in controlling the tensile strength was assessed and discussed.
{"title":"Tensile Behavior of Tetragonal Zirconia Micro/Nano-Fibers and Beams In-Situ Tested in Push-to-Pull Devices","authors":"X. Zeng, P. Ye, Z. Du, C. Gan","doi":"10.2139/ssrn.3939455","DOIUrl":"https://doi.org/10.2139/ssrn.3939455","url":null,"abstract":"The tensile mechanical behaviour of tetragonal zirconia micro/nano-fibers and beams were studied with a push-to-pull (PTP) device equipped in an in-situ nanoindenter. Polycrystalline and oligocrystalline micro/nano-fibers exhibited some degree of plastic strain before fracture with the tensile strength ranging from ~0.9 GPa to 1.4 GPa. Single-crystal beams generally experienced linear elastic deformation with tensile strength of ~2.1-3.4 GPa. No martensitic transformation induced shape memory strain was detected in the zirconia fibers and beams. Further variation of dopant concentration and crystal orientation was explored for single-crystalline beams and their significance in controlling the tensile strength was assessed and discussed.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"110 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77336753","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}
Hung Ba Tran, H. Momida, Kazunori Sato, Y. Makino, T. Oguchi, T. Fukushima
There are two types of magnetocaloric effects that are the so-called direct and inverse effects originating from ferromagnetic-paramagnetic (FM-PM) and antiferromagnetic--ferromagnetic (AFM-FM) phase transitions, respectively. Here, the magnetocaloric effects of FeRh alloy, which exhibit both the direct and inverse effects, have been studied by combining first-principles calculations and Monte-Carlo simulations. The magnetic exchange coupling constants in the AFM and FM phases are evaluated by first-principles calculations based on the Liechtenstein formula. The Monte-Carlo calculations considering the two-phase mixtures of AFM and FM well reproduce the experimental magnetization curves at zero external magnetic field. It is also shown that the isothermal magnetic entropy changes near the AFM-FM transition temperature under magnetic fields are successfully reproduced based on the Maxwell relation. The entropy changes in a wide range of the magnetic fields near the AFM-FM and FM-PM transition temperatures are investigated and the direct and inverse magnetocaloric effects of FeRh are discussed. The giant relative cooling power of FeRh alloy is achieved due to the large saturation magnetizations and the first-order AFM-FM phase transition.
{"title":"Direct and Inverse Magnetocaloric Effects in FeRh Alloy: A Theoretical Study","authors":"Hung Ba Tran, H. Momida, Kazunori Sato, Y. Makino, T. Oguchi, T. Fukushima","doi":"10.2139/ssrn.3799705","DOIUrl":"https://doi.org/10.2139/ssrn.3799705","url":null,"abstract":"There are two types of magnetocaloric effects that are the so-called direct and inverse effects originating from ferromagnetic-paramagnetic (FM-PM) and antiferromagnetic--ferromagnetic (AFM-FM) phase transitions, respectively. Here, the magnetocaloric effects of FeRh alloy, which exhibit both the direct and inverse effects, have been studied by combining first-principles calculations and Monte-Carlo simulations. The magnetic exchange coupling constants in the AFM and FM phases are evaluated by first-principles calculations based on the Liechtenstein formula. The Monte-Carlo calculations considering the two-phase mixtures of AFM and FM well reproduce the experimental magnetization curves at zero external magnetic field. It is also shown that the isothermal magnetic entropy changes near the AFM-FM transition temperature under magnetic fields are successfully reproduced based on the Maxwell relation. The entropy changes in a wide range of the magnetic fields near the AFM-FM and FM-PM transition temperatures are investigated and the direct and inverse magnetocaloric effects of FeRh are discussed. The giant relative cooling power of FeRh alloy is achieved due to the large saturation magnetizations and the first-order AFM-FM phase transition.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87663439","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}
Raymond Akong Akong, H. Görls, J. Woods, W. Plass, A. O. Eseola
The need to explore possible benefits of molecular substituent derivatization on fluorescent chemosensor properties motivated the syntheses of six potentially pentadentate bis-(phenol-imine) fluorophores, which consist of five S-bridged O^N^S^N^O scaffolds 1 – 5 and an O-bridged O^N^O^N^O scaffold 6 . The deliberate incorporation of multiple intramolecular N … H–O donor-acceptor functions into the molecules helped to achieve Excited State Intramolecular Proton-electron Transfer (ESIPT) capability as well as the possession of low quantum yields in their ligand-only solutions. Interestingly, while the low quantum yield molecules 1 , 2 , 3 and 6 lacked the expected large Stokes shifted ESIPT fluorescence in their ligand-only solutions, they utilize the same ESIPT-oriented process to achieve varying extents of substituent-dependent fluorescent turn-on that produced sensitive and selective Al 3+ detection. In particular, while molecules 1 and 3 gave dual-band fluorescence turn-on from both primary and secondary photoexcited states, the O-bridged ligand 6 is strongly turned on only at the large Stokes shifted ESIPT emission wavelength. Thus, with a 528-fold F / F o turn-on ratio and a detection limit of 5.48 × 10 -9 M, the efficiency of molecule 6 as chemosensor towards Al 3+ detection can be considered to be outstanding. Based on results of Job plot experiment, fluorescent intensities during Al 3+ titration, single crystal structural data and 1 H-NMR spectral analyses, we conclude that a 1:1 sensor-to-analyte stoichiometry is at play in the Al 3+ sensing mechanism and that the sensor molecules form an unusual bidentate O^O coordination with the analyte as neutral iminium zwitterion. It could be concluded that synthetic designs leading to systematic substituent variation is a beneficial tool for tuning and isolating applicable molecular chemosensor species.
{"title":"ESIPT-Inspired Fluorescent Turn-On Sensitivity Towards Aluminium (III) Detection by Derivatives of O- and S-Bridged Bis-(Phenol-Imine) Molecules","authors":"Raymond Akong Akong, H. Görls, J. Woods, W. Plass, A. O. Eseola","doi":"10.2139/ssrn.3880392","DOIUrl":"https://doi.org/10.2139/ssrn.3880392","url":null,"abstract":"The need to explore possible benefits of molecular substituent derivatization on fluorescent chemosensor properties motivated the syntheses of six potentially pentadentate bis-(phenol-imine) fluorophores, which consist of five S-bridged O^N^S^N^O scaffolds 1 – 5 and an O-bridged O^N^O^N^O scaffold 6 . The deliberate incorporation of multiple intramolecular N … H–O donor-acceptor functions into the molecules helped to achieve Excited State Intramolecular Proton-electron Transfer (ESIPT) capability as well as the possession of low quantum yields in their ligand-only solutions. Interestingly, while the low quantum yield molecules 1 , 2 , 3 and 6 lacked the expected large Stokes shifted ESIPT fluorescence in their ligand-only solutions, they utilize the same ESIPT-oriented process to achieve varying extents of substituent-dependent fluorescent turn-on that produced sensitive and selective Al 3+ detection. In particular, while molecules 1 and 3 gave dual-band fluorescence turn-on from both primary and secondary photoexcited states, the O-bridged ligand 6 is strongly turned on only at the large Stokes shifted ESIPT emission wavelength. Thus, with a 528-fold F / F o turn-on ratio and a detection limit of 5.48 × 10 -9 M, the efficiency of molecule 6 as chemosensor towards Al 3+ detection can be considered to be outstanding. Based on results of Job plot experiment, fluorescent intensities during Al 3+ titration, single crystal structural data and 1 H-NMR spectral analyses, we conclude that a 1:1 sensor-to-analyte stoichiometry is at play in the Al 3+ sensing mechanism and that the sensor molecules form an unusual bidentate O^O coordination with the analyte as neutral iminium zwitterion. It could be concluded that synthetic designs leading to systematic substituent variation is a beneficial tool for tuning and isolating applicable molecular chemosensor species.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"487 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76377683","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}
B. Sahoo, S. Han, Nagendra Prasad Yerriboina, Hyun-Tae Kim, K. Ando, Tae-Gon Kim, Brown Kang, A. Klipp, Jin-Goo Park
Acoustic cavitation is used for megasonic cleaning in the semiconductor industry, especially of wafers with fragile pattern structures. Control of transient cavitation is necessary to achieve high particle removal efficiency (PRE) and low pattern damage (PD). In this study, the cleaning performance of solutions with different concentrations of dissolved gas (H2) and anionic surfactant (sodium dodecyl sulfate, SDS) in DIW (DI water) on silicon (Si) wafers was evaluated in terms of PRE and PD. When only DIW was used, PRE was low and PD was high. An increase in dissolved H2 gas concentration in DIW increased PRE; however, PD also increased accordingly. Thus, we investigated the megasonic cleaning performance of DIW and H2-DIW solutions with various concentrations of the anionic surfactant, SDS. At 20 ppm SDS in DIW, PRE reached a maximum value and then decreased with increasing concentration of SDS. PRE decreased slightly with increasing concentrations of SDS surfactant when dissolved in H2-DIW. Furthermore, PD decreased significantly with increasing concentrations of SDS surfactant in both DIW and H2-DIW cases. A high-speed camera setup was introduced to analyze bubble dynamics under a 0.96 MHz ultrasonic field. Coalescence, agglomeration, and the population of multi-bubbles affected the PRE and PD of silicon wafers differently in the presence of SDS surfactant. We developed a hypothesis to explain the change in bubble characteristics under different chemical environmental conditions.
{"title":"Controlled Megasonic Cleaning of Patterned Structures Using Solutions with Dissolved Gas and Surfactant","authors":"B. Sahoo, S. Han, Nagendra Prasad Yerriboina, Hyun-Tae Kim, K. Ando, Tae-Gon Kim, Brown Kang, A. Klipp, Jin-Goo Park","doi":"10.2139/ssrn.3873713","DOIUrl":"https://doi.org/10.2139/ssrn.3873713","url":null,"abstract":"Acoustic cavitation is used for megasonic cleaning in the semiconductor industry, especially of wafers with fragile pattern structures. Control of transient cavitation is necessary to achieve high particle removal efficiency (PRE) and low pattern damage (PD). In this study, the cleaning performance of solutions with different concentrations of dissolved gas (H<sub>2</sub>) and anionic surfactant (sodium dodecyl sulfate, SDS) in DIW (DI water) on silicon (Si) wafers was evaluated in terms of PRE and PD. When only DIW was used, PRE was low and PD was high. An increase in dissolved H<sub>2</sub> gas concentration in DIW increased PRE; however, PD also increased accordingly. Thus, we investigated the megasonic cleaning performance of DIW and H<sub>2</sub>-DIW solutions with various concentrations of the anionic surfactant, SDS. At 20 ppm SDS in DIW, PRE reached a maximum value and then decreased with increasing concentration of SDS. PRE decreased slightly with increasing concentrations of SDS surfactant when dissolved in H<sub>2</sub>-DIW. Furthermore, PD decreased significantly with increasing concentrations of SDS surfactant in both DIW and H<sub>2</sub>-DIW cases. A high-speed camera setup was introduced to analyze bubble dynamics under a 0.96 MHz ultrasonic field. Coalescence, agglomeration, and the population of multi-bubbles affected the PRE and PD of silicon wafers differently in the presence of SDS surfactant. We developed a hypothesis to explain the change in bubble characteristics under different chemical environmental conditions.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81609004","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}
Qianqian Zhang, Zhihua Tian, Peigen Zhang, Shuai Li, Yan Zhang, Yushuang Liu, Long Pan, W. He, Zhengming Sun
Metallic whiskers grown on MAX phases bring concerns on their stability, and draw intense attention because of the impressing similarity they share with the troublesome tin whiskers primarily found on Sn-based solders in electronics. Herein, we report the mushrooming of tin whiskers associated with Ti2SnC, a MAX phase, and the whisker growth propensity correlated with the decomposition degree of Ti2SnC. Tin atoms, exposed as Ti2SnC mechanochemically decomposes, have high chemical potential and therefore can fast crystallize by “short-circuit” diffusion. Fascinatingly, the similar phenomenon happens to several other MAX phases, and the composition of whiskers is adjustable, boding well a paradigm-shifting means for preparing metallic whiskers. The fundamental role of active tin atoms in whisker growth manifested here shall lay foundation for developing whisker-mitigating methods for MAX phases, and furthermore, help comprehensively understand the growth mechanism of the tin whiskers haunted electronic industry for many decades.
{"title":"Metallic Whiskers Mushrooming on Mechanochemically Decomposed MAX Phases","authors":"Qianqian Zhang, Zhihua Tian, Peigen Zhang, Shuai Li, Yan Zhang, Yushuang Liu, Long Pan, W. He, Zhengming Sun","doi":"10.2139/ssrn.3920961","DOIUrl":"https://doi.org/10.2139/ssrn.3920961","url":null,"abstract":"Metallic whiskers grown on MAX phases bring concerns on their stability, and draw intense attention because of the impressing similarity they share with the troublesome tin whiskers primarily found on Sn-based solders in electronics. Herein, we report the mushrooming of tin whiskers associated with Ti2SnC, a MAX phase, and the whisker growth propensity correlated with the decomposition degree of Ti2SnC. Tin atoms, exposed as Ti2SnC mechanochemically decomposes, have high chemical potential and therefore can fast crystallize by “short-circuit” diffusion. Fascinatingly, the similar phenomenon happens to several other MAX phases, and the composition of whiskers is adjustable, boding well a paradigm-shifting means for preparing metallic whiskers. The fundamental role of active tin atoms in whisker growth manifested here shall lay foundation for developing whisker-mitigating methods for MAX phases, and furthermore, help comprehensively understand the growth mechanism of the tin whiskers haunted electronic industry for many decades.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87776555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kalaimathi, K. Hariharan, S. Vishnu, Harishbabu Harishbabu, R. Chinnasamy
The Magnesium oxide nanoparticles were successfully synthesized using Magnesium nitrate as the precursor and extract of Tridax procumbens leaf and Myristica fragrance (Nutmeg) were used as the reducing and stabilizing agent. Two parallel synthesis of Magnesium oxide nanoparticles were carried out. Synthesized Magnesium oxide particles in nano size were characterized by FT-IR, Ultraviolet-visible SEM & XRD techniques. The formed nanoparticles were confirmed as Magnesium oxide nanoparticles by UV- Visible, FT-IR spectroscopic techniques. The structure and size of the Magnesium oxide nanoparticles were obtained from XRD analysis. The size of the Magnesium oxide nanoparticles was 20.10 nm and 9.21 nm. SEM analysis results sphere like and rhombic crystalline shape and morphology of Magnesium oxide nanoparticles.
{"title":"Parallel Synthesis and Optimization of Magnesium Oxide Nanoparticles Using Tridax Procumbens and Myristica Fragrance","authors":"M. Kalaimathi, K. Hariharan, S. Vishnu, Harishbabu Harishbabu, R. Chinnasamy","doi":"10.2139/ssrn.3902669","DOIUrl":"https://doi.org/10.2139/ssrn.3902669","url":null,"abstract":"The Magnesium oxide nanoparticles were successfully synthesized using Magnesium nitrate as the precursor and extract of Tridax procumbens leaf and Myristica fragrance (Nutmeg) were used as the reducing and stabilizing agent. Two parallel synthesis of Magnesium oxide nanoparticles were carried out. Synthesized Magnesium oxide particles in nano size were characterized by FT-IR, Ultraviolet-visible SEM & XRD techniques. The formed nanoparticles were confirmed as Magnesium oxide nanoparticles by UV- Visible, FT-IR spectroscopic techniques. The structure and size of the Magnesium oxide nanoparticles were obtained from XRD analysis. The size of the Magnesium oxide nanoparticles was 20.10 nm and 9.21 nm. SEM analysis results sphere like and rhombic crystalline shape and morphology of Magnesium oxide nanoparticles.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"204 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76943133","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}
Behnam Nourmohammadi Khiarak, Kaveh Shariati, M. Mojaddami, Zahra Zamani, A. Zekiy, A. Simchi
The development of active, durable, cost-effective, and stable electrocatalysts are of urgent need for various industrial fields including renewable energy systems. State-of-the-art catalysts suffer from poor water splitting activity in alkaline media due to sluggish kinetics, high cost and scarcity on earth to be scaled up. Herein, we present an electrochemical analysis of a nanostructured electrocatalyst based on face center cubic Cu-Ni-Fe-Co-Cr high entropy alloy (HEA) with quasi-spherical morphology. Single-phase, face-center cubic HEA was prepared by a one-step electrochemical deposition technique on a highly porous nickel substrate. Electrochemical studies determine the enhanced electrocatalytic activity of HEA induced by the synergistic effect of mixed transition metals. It is shown that the performance of the HEA electrocatalyst for both oxygen evolution reaction and hydrogen evolution reaction is superior to recently reported electrocatalysts for overall water splitting. Benefiting from its long-term durability, the material can pave a way to develop high-performance electrocatalysts for full electrochemical water splitting.
{"title":"Efficient Electrocatalytic Overall Water Splitting on a Cu-Based High Entropy Alloy: An Electrochemical Study","authors":"Behnam Nourmohammadi Khiarak, Kaveh Shariati, M. Mojaddami, Zahra Zamani, A. Zekiy, A. Simchi","doi":"10.2139/ssrn.3889206","DOIUrl":"https://doi.org/10.2139/ssrn.3889206","url":null,"abstract":"The development of active, durable, cost-effective, and stable electrocatalysts are of urgent need for various industrial fields including renewable energy systems. State-of-the-art catalysts suffer from poor water splitting activity in alkaline media due to sluggish kinetics, high cost and scarcity on earth to be scaled up. Herein, we present an electrochemical analysis of a nanostructured electrocatalyst based on face center cubic Cu-Ni-Fe-Co-Cr high entropy alloy (HEA) with quasi-spherical morphology. Single-phase, face-center cubic HEA was prepared by a one-step electrochemical deposition technique on a highly porous nickel substrate. Electrochemical studies determine the enhanced electrocatalytic activity of HEA induced by the synergistic effect of mixed transition metals. It is shown that the performance of the HEA electrocatalyst for both oxygen evolution reaction and hydrogen evolution reaction is superior to recently reported electrocatalysts for overall water splitting. Benefiting from its long-term durability, the material can pave a way to develop high-performance electrocatalysts for full electrochemical water splitting.","PeriodicalId":10639,"journal":{"name":"Computational Materials Science eJournal","volume":"134 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74711884","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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