bluuebunny/crossref_metadata_2025 huggingface dataset:
Geo-societal sense-making
Authors: Bohle Martin
Published: September 2020

At present, only geoscientists utilize geoethics. However, geoethics may have broader, societal use. To illustrate this option, one combines theoretical insights that stem from complex–adaptive dynamics, social–ecological systems, semiotic–cultural psychology and geoethics. The following qualitative framework appears. The human niche is a network of complex–adaptive social–ecological systems, which humans conceive and build to sustain themselves. Human sense-making and practices are intrinsic and non-separable parts of the human niche. The feedback of human sense-making and human practices is iterative. The resulting feedback loop is pivotal for the dynamics of social–ecological systems. Geosciences facilitate the understanding of the dynamics of social–ecological systems. Geoethics supports the sense-making of human agents, such as, currently, geoscientists acting in a professional capacity. However, geoethics is not geoscience-specific when promoting to act actor-centric, virtue-ethics-focused, responsibility-focused and knowledge-based. Therefore, geoethics may shape societal practices beyond professional geosciences. By delivering analytical insights as well as resources for affective sense-making, geoethics may enable citizens to mitigate the challenges to their sense-making that complex–adaptive social–ecological systems may pose. Hence, geoethics may offer cultural references (analytical and affective) when human agents (individual, collective and institutional) are facing the complex–adaptive (wicked) features of the human niche, such as anthropogenic pressure or participatory governance.
What do agile, lean, and ITIL mean to DevOps?
Authors: Galup Stuart , Dattero Ronald , Quan Jing
Published: September 2020

The value of learning skillsets within a trio of disciplines and the role each plays in DevOps.
Debugging incidents in Google's distributed systems
Authors: Chan Charisma , Cooper Beth
Published: September 2020

How experts debug production issues in complex distributed systems.
MadMax
Authors: Grech Neville , Kong Michael , Jurisevic Anton , Brent Lexi , Scholz Bernhard , Smaragdakis Yannis
Published: September 2020

Ethereum is a distributed blockchain platform, serving as an ecosystem for smart contracts: full-fledged intercommunicating programs that capture the transaction logic of an account. A gas limit caps the execution of an Ethereum smart contract: instructions, when executed, consume gas, and the execution proceeds as long as gas is available.

Gas-focused vulnerabilities permit an attacker to force key contract functionality to run out of gas---effectively performing a permanent denial-of-service attack on the contract. Such vulnerabilities are among the hardest for programmers to protect against, as out-of-gas behavior may be uncommon in nonattack scenarios and reasoning about these vulnerabilities is nontrivial.

In this paper, we identify gas-focused vulnerabilities and present MadMax: a static program analysis technique that automatically detects gas-focused vulnerabilities with very high confidence. MadMax combines a smart contract decompiler and semantic queries in Datalog. Our approach captures high-level program modeling concepts (such as "dynamic data structure storage" and "safely resumable loops") and delivers high precision and scalability. MadMax analyzes the entirety of smart contracts in the Ethereum blockchain in just 10 hours and flags vulnerabilities in contracts with a monetary value in billions of dollars. Manual inspection of a sample of flagged contracts shows that 81% of the sampled warnings do indeed lead to vulnerabilities.
A holistic view of future risks
Authors: Neumann Peter G.
Published: September 2020

Almost everything is somehow interrelated with everything else---and that should not surprise us.
An Accidental Nutritionist
Authors: Sommer Alfred
Published: September 2020

My career as an accidental nutritionist began with my immersion in cholera control, a cyclone disaster, a smallpox epidemic, and formal training in ophthalmology and epidemiology. Interest in blindness prevention inexplicably led me to (re)pioneer the effects, treatment, and prevention of vitamin A deficiency, while faced with intense criticism by many leading scientists in the nutrition community. The resulting efforts by the World Health Organization and UNICEF in support of programs for the global control of vitamin A deficiency still face vocal opposition by some senior scientists, despite having been estimated to have saved tens of millions of children from unnecessary death and blindness. This entire journey was largely an accident!
Vitamin A and Retinoic Acid in Cognition and Cognitive Disease
Authors: Wołoszynowska-Fraser Marta U. , Kouchmeshky Azita , McCaffery Peter
Published: September 2020

The history of vitamin A goes back over one hundred years, but our realization of its importance for the brain and cognition is much more recent. The brain is more efficient than other target tissues at converting vitamin A to retinoic acid (RA), which activates retinoic acid receptors (RARs). RARs regulate transcription, but their function in the cytoplasm to control nongenomic actions is also crucial. Controlled synthesis of RA is essential for regulating synaptic plasticity in regions of the brain involved in learning and memory, such as the hippocampus. Vitamin A deficiency results in a deterioration of these functions, and failure of RA signaling is perhaps associated with normal cognitive decline with age as well as with Alzheimer's disease. Further, several psychiatric and developmental disorders that disrupt cognition are also linked with vitamin A and point to their possible treatment with vitamin A or RA.
Drinking Water in the United States: Implications of Water Safety, Access, and Consumption
Authors: Patel Anisha I. , Hecht Christina E. , Cradock Angie , Edwards Marc A. , Ritchie Lorrene D.
Published: September 2020

Recent water quality crises in the United States, and recognition of the health importance of drinking water in lieu of sugar-sweetened beverages, have raised interest in water safety, access, and consumption. This review uses a socioecological lens to examine these topics across the life course. We review water intakes in the United States relative to requirements, including variation by age and race/ethnicity. We describe US regulations that seek to ensure that drinking water is safe to consume for most Americans and discuss strategies to reduce drinking water exposure to lead, a high-profile regulated drinking water contaminant. We discuss programs, policies, and environmental interventions that foster effective drinking water access, a concept that encompasses key elements needed to improve water intake. We conclude with recommendations for research, policies, regulations, and practices needed to ensure optimal water intake by all in the United States and elsewhere.
Policy Progress in Reducing Sodium in the American Diet, 2010–2019
Authors: Musicus Aviva A. , Kraak Vivica I. , Bleich Sara N.
Published: September 2020

Most Americans consume dietary sodium exceeding age-specific government-recommended targets of 1,500–2,300 mg/day per person. The majority (71%) of US dietary sodium comes from restaurant and packaged foods. Excess sodium intake contributes to hypertension and cardiovascular disease, which is the leading cause of death in the United States. This review summarizes evidence for policy progress to reduce sodium in the US food supply and the American diet. We provide a historical overview of US sodium-reduction policy (1969–2010), then examine progress toward implementing the 2010 National Academy of Medicine (NAM) sodium report's recommendations (2010–2019). Results suggest that the US Food and Drug Administration made no progress in setting mandatory sodium-reduction standards, industry made some progress in meeting voluntary targets, and other stakeholders made some progress on sodium-reduction actions. Insights from countries that have significantly reduced population sodium intake offer strategies to accelerate US progress toward implementing the NAM sodium-reduction recommendations in the future.
Impact of Carbon Support Structure on the Durability of PtCo Electrocatalysts
Authors: O'Brien Thomas E. , Herrera Sergio A. , Langlois David A. , Kariuki Nancy N. , Yu Haoran , Myers Deborah J. , Cullen David A. , Borup Rod L. , Mukundan Rangachary
Published: September 2020

High performing, low-Pt content fuel cell membrane electrode assemblies (MEAs) are critical to the economic viability of proton exchange membrane fuel cells (PEMFCs) for the transportation industry. Considerable research has been conducted to reduce the Pt content in fuel cells, leading to the development of transition metal alloys, such as Platinum-Cobalt (PtCo). The degree of degradation of PtCo catalysts can be impacted by the catalyst metal itself and its interactions with the carbon support. Several low-loaded PtCo MEAs were fabricated, with various combinations of porous and solid carbon cathode catalyst supports. The MEAs were subjected to an accelerated stress test (AST), and the catalyst degradation characterized using electrochemical, X-ray scattering, and electron microscopy techniques. Porous supports retain more of their electrochemically-active surface area (ECSA) and demonstrate higher performance after the AST. This is believed to be due to the ability of the porous supports to trap the metal particles within the pores, slowing their dissolution/precipitation, and agglomeration.
Nanostructuring Pt Electrocatalysts Supported on Nanocrystalline SnO2 for Polymer Electrolyte Fuel Cells
Authors: Yoshizumi Tsubasa , Noda Zhiyun , Matsuda Junko , Nishihara Masamichi , Hayashi Akari , Sasaki Kazunari
Published: September 2020

For nanostructuring PEFC electrocatalysts using oxides stable under strongly acidic conditions, freeze drying is applied as an effective fabrication procedure for highly dispersing SnO2 nanoparticles of a few nanometers in diameter, on relatively-stable conductive framework in the electrocatalyst layers. Platinum catalysts are deposited on SnO2 nanocrystals on an atomic level by applying a chemical procedure for preparing oxide-core Pt-shell electrocatalysts. Their high-resolution STEM images and preliminary electrochemical results are reported, and remaining issues are discussed.
Influence of Ammonia Contamination on HT-PEM Fuel Cell Platinum Catalyst
Authors: Dushina Anastasia , Schonvogel Dana , Fischer Yannis , Büsselmann Julian , Dyck Alexander , Wagner Peter
Published: September 2020

In this work the effect of NH3 contamination on platinum catalyst has been investigated in the frame of a high temperature polymer electrolyte membrane single fuel cell as well as rotating ring disk electrode measurements (RRDE) using phosphoric acid electrolyte. In the first part single cell operation in presence of 10 ppm NH3 in the cathode gas combined with electrochemical impedance spectroscopy was performed with a fuel cell test bench. In the second part of work RRDE experiments were accomplished in the presence of 10 and 100 ppm of NH4H2PO4 contamination in 0.5 mol L-1 H3PO4. It was revealed that platinum catalyst is strongly affected by ammonia contamination while the increasing ammonium concentrations reduce the electrochemical surface area (ECSA) of the Pt catalyst. These observed losses of ECSA were associated to adsorbed nitrogen compounds on the catalyst surface.
Porous Metal Support for Gas Diffusion Electrode of PEFCs
Authors: Ikehara Teppei , Noda Zhiyun , Matsuda Junko , Nishihara Masamichi , Hayashi Akari , Sasaki Kazunari
Published: September 2020

Carbon support, widely used for electrocatalysts of polymer electrolyte fuel cells (PEFCs), tends to corrode under high potential conditions. Therefore, metal oxides stable even under PEFC conditions have been proposed as alternative support materials. Here in this study, porous metals are applied to catalyst support materials, where stable metal oxide is formed on the outermost surface. As model materials, metallic titanium sintered sheets are examined, as their oxides (TiO2) are expected to have high durability under PEFC conditions. Porous metal sheets can also act as gas diffusion layer (GDL). Such unique structure, in which both the electrocatalyst layer and the GDL are integrated, has a potential to simplify the MEA structure and possibly fabrication processes. Such catalyst-integrated electrodes are prepared, and their microstructure and electrochemical properties are evaluated.
Electrochemical Synthesis of Polyaniline on Onion-like Carbon Nanoparticles Using the RoDSE Technique
Authors: Vargas Pérez Brenda Lee , Sanchéz Fonseca Fabiola Noemí , Gonzalez-Aponte Kattia Mitchelle , Cunci Lisandro
Published: September 2020

The main source of energy in the world is fossil fuels, but these can irreparably harm the environment. My research focuses on making a catalyst that is economical, efficient, and environmentally friendly. The ORR is an important reaction for energy conversion systems, such as fuel cells. OLC is used as a catalytic support for fuel cell applications due to its high conductivity and surface-to-volume ratio. The combination of carbon compounds with conductive polymers results in new materials and devices with possible practical applications. In my research we obtain OLC from nanodiamonds through a pyrolysis process. These particles are then polymerized using the aniline monomer to dope the OLCs with nitrogen.
Template Synthesis of Ag@Fe-N-Doped Carbon Electrocatalyst for Oxygen Reduction Reaction in Alkaline Media
Authors: Gong Chong , Wang Zhihuan , Chen Xing , Chen Yingjie , Yu Liyan , Dong Lifeng
Published: September 2020

A simple template method is proposed for the synthesis of Ag nanoparticles embedded in Fe-N-C (Ag@FeNC) as excellent oxygen reduction reaction (ORR) catalyst. Firstly, Ag@Fe3O4 nanoparticles are synthesized and loaded onto graphene oxide to form the Ag@Fe3O4-GO template. The surface of the template is then enveloped by polypyrrole. After pyrolysis at 850°C for 1 h, Ag@FeNC is synthesized and demonstrates excellent ORR catalytic activity in alkaline medium. Therefore, it provides a simple method for preparing metal@Fe-N-C hybrid catalysts.
Large-Scale Coupling Numerical Simulation of Two-Phase Flow and Electrochemical Phenomena in Alkaline Water Electrolysis
Authors: Murakami Naoki , Kiuchi Takeshi , Kodama Manabu , Hirai Shuichiro
Published: September 2020

The alkaline water electrolysis is one of large-scale hydrogen production methods. While a lot of experiments and numerical simulations have been conducted to elucidate the internal phenomena and to improve the efficiency of the alkaline water electrolysis, there still is room for improvement in the efficiency. In this study, large-scale coupling numerical simulations of two-phase flow and electrochemical phenomena are conducted to elucidate the influence of the bubble-bubble interactions on ion transport and cell overpotential. The results showed that the interaction between bubbles affects cell overpotential, and cell overpotential can be suppressed when bubbles are optimally dispersed.
Considering Two-Phase Flow in Three-Dimensional Computational Fluid Dynamics Simulations of Proton Exchange Membrane Water Electrolysis Devices
Authors: Lopata Joseph Steven , Kang Zhenye , Young James L. , Bender Guido , Weidner John W. , Cho Hyun-Seok , Shimpalee Sirivatch
Published: September 2020

Simulations help us to understand electrochemical systems and reduce the cost of research and development. Modeling proton exchange membrane water electrolysis (PEMWE) devices, especially in order to screen components such as the flow field and PTL, is challenging due to two-phase flow. However, this offers an opportunity to advance computational fluid dynamics (CFD) modeling of these systems. We employed CFD to simulate a liquid-fed, straight-channel PEMWE device, exploring the viability of an isothermal continuum model. The results agree with observations of two-phase flow recorded in literature.
Grid Scale Energy Storage: Modeling of Electrolyzer-Fuel Cell Combination and Comparison with Flow Batteries
Authors: Motupally Saagar , Pasaogullari Ugur
Published: September 2020

Life cycle cost modeling of hydrogen production via Polymer Electrolyte Membrane (PEM) and Solid Oxide (SO) electrolysis and discharge via fuel cell combination is investigated for large grid scale baseload storage applications. The cost of hydrogen in $/kg and storage energy produced in $/kWh are compared for four cases. The high-end simulations assume parameters that are capable within the next five years and low-end cases represent post significant improvements in the cost and durability of the technologies in the next couple of decades. The levelized cost of gclose to commercialization scale (low-end) for PEM and SO electrolysis is calculated to be ~$1.6 per kg. Levelized cost of energy (LCOE) calculations with this cost of hydrogen coupled with fuel cells is ~$0.10 per kWh. These values compare favorably to future flow battery potential where an LCOE of ~$0.09 per kWh is possible.
Electrocatalytic Hydrogen Evolution Reaction with Multilayer Graphene-Covered Ni Particles Synthesized by Microwave-Assisted Catalytic Methane Decomposition
Authors: Kodera Fumihiro , Yoshida Narumi , Inoue Mitsuhiro , Umeda Minoru , Miyakoshi Akihiko
Published: September 2020

We developed a new method for the production of large amounts of carbon–nickel (C–Ni) powder, which contained multilayer graphene-covered Ni particles as the main component, using multimode microwave-assisted catalytic CH4 decomposition. Electrocatalytic hydrogen evolution reaction of the C–Ni powder in acidic solution was investigated using electrochemical method. The C–Ni powder can be used as a noble metal-free electrocatalyst to implement the hydrogen evolution reaction with good electrochemical performance in the acidic solution.
(Physical and Analytical Electrochemistry Division Max Bredig Award Address In Molten Salt and Ionic Liquid Chemistry) The Ionic Melting Pot: My Research in Molten Salts and Ionic Liquids
Authors: Dai Sheng
Published: September 2020

Molten salts and ionic liquids are a unique class of solvents that offer many advantages, such as negligible vapor pressures, wide liquidus ranges, good thermal stability, and tunable solubilities of both organic and inorganic species. This presentation will provide an overview of my research in the following five areas related to molten salts and ionic liquids: (1) speciation and thermodynamics of actinides and fission products in molten salts, (2) metal-ion extraction based on ionic liquids, (3) gas separation through functionalized ionic liquids, (3) synthesis of functional materials (e.g, carbon, porous materials) using molten salts and ionic liquids as reaction media, (4) electrolytes based on task-specific ionic liquids, and (5) emerging porous ionic liquids. The overall goal of my research is to investigate fundamental principles underpinning ionic media through tailored interactions for energy-related applications.
Process Engineering Challenges for the Development of Electrolytic Reduction of Uranium Oxide in Molten LiCl-Li2O
Authors: Chamberlain Jarom L , Burak Adam J , Gonzalez Mario , Simpson Michael Forrest
Published: September 2020

Electrolytic uranium oxide reduction has the potential to be used for recycling spent fuel to a range of nuclear reactors from commercial light water reactors to advanced nuclear reactors—including molten salt reactors and sodium cooled reactors. However, several process engineering-related problems have been identified that need to be addressed to support efficient, cost-effective commercial implementation. Two keys are cathode product purity and cell current efficiency. High product purity relies upon the effective removal of LiCl-Li2O from the cathode basket and reduced uranium. Removal of the salt from the basket can be achieved via high speed spinning at 650oC. But entrained Li2O will remain and should be minimized during the reduction process. Methods for removing hydroxide impurities from the salt are reported that improve cell-current efficiency. The extent of this reduction can be determined via three distinct techniques (thermogravimetric analysis, elemental oxygen analysis, and bromine dissolution) and is key in helping determine the efficiency of the electrochemical cell.
Rare Earth Silicide Formation on Si Electrode in LiCl-KCl Melt to Establish a Novel Used Salt Treatment Process
Authors: Murakami Tsuyoshi , Sakamura Yoshiharu , Uozumi Koichi , Iizuka Masatoshi
Published: September 2020

After repeating the electrorefining of spent nuclear fuels, rare earth, alkaline earth, and alkali fission products accumulate in the used LiCl-KCl melt. This paper proposes a novel used salt treatment process where dominant fission products, rare earths, are recovered electrochemically from the used melt in a form of their silicides and the silicides are then oxidized to be dissolved in a glass matrix as the waste form. The glass waste form stabilizing a higher concentration of fission products than the conventional waste form provides a reduction in volume of the waste form. The results of cyclic voltammetry using a Si electrode in LiCl-KCl melt containing a rare earth chloride (LaCl3, CeCl3, PrCl3, NdCl3, SmCl2, EuCl2, or GdCl3) at 723 K indicated the corresponding lanthanide silicide formation. The rare earth silicides formed by potentiostatic electrolysis were analyzed by XRD and SEM-EDX. The obtained results confirmed a feasibility of rare earths recovery as silicides from the used LiCl-KCl melt, which was a key step of the proposed used salt treatment process.
Electrochemical Techniques to Monitor the Concentration of Oxide in Molten FLiNaK Salt
Authors: Choi Suhee , Strianese Andrew R. , Simpson Michael Forrest
Published: September 2020

The effect of oxide concentration in molten FLiNaK (LiF-NaF-KF) salt on square wave voltammetry (SWV) oxidation peak heights using tungsten working electrodes was determined and compared to the results of acid-base titration of solid salt samples. SWV oxidation current was observed to be more sensitive than that of cyclic voltammetry (CV), possibly due to the elimination of non-faradaic current. The in-situ measurements of the O2- concentrations in the molten salt using SWV showed good agreement with the results obtained from the acid-base titration method.
Electrochemical Reduction Behavior of Boron in Molten LiCl–KCl–KBF4
Authors: Katasho Yumi , Oishi Tetsuo
Published: September 2020

Although the electrochemical behavior of Nd and Dy in Ne-Fe-B magnets has been investigated, the behavior of B in molten salt has not been clarified yet. Herein, the electrochemical reduction behavior of B(III) is investigated in molten LiCl–KCl–KBF4 at 723 K. A comparison of the cyclic voltammograms for Ni, Mo, and Ag electrodes suggests that Ni–B compounds were formed on the Ni electrode, and that the reduction of B(III) to B(0) occurred on the Ni, Mo, and Ag electrodes. Ni2B was confirmed to form on the Ni electrode by potentiostatic electrolysis at 1.3 V vs. Li+/Li. Granular deposits were observed on the same electrode. An Ag substrate was also electrolyzed at 1.3 V. Granular deposits were observed. However, in both cases, the presence of elemental B was not confirmed yet at this time.
(Invited) Electrical Conductivity of Ceria-Based Oxide/Alkali Carbonate Eutectics Nanocomposites
Authors: Mizuhata Minoru , Kubo Hiroshi , Ichikawa Yudai , Maki Hideshi , Matsui Masaki
Published: September 2020

Thermal properties and the electrical conductivity for the SDC/ternary carbonate coexisting system was measured and the influence of the solid phase was discussed. In the ceria-based oxide/carbonate coexistence system, the melting enthalpy of carbonate disappeared when the liquid phase volume fraction was less than 45 vol%, and the melting point decreased due to the influence of the solid phase. The activation energy of conductivity increases in the region where the apparent average thickness is approximately 0.5 nm or less, the carbonate is significantly affected by the solid phase in a very narrow range, and the ceria-based oxide causes ion migration in the interface layer. It became clear that it did not inhibit. From these results, it was clarified that the low temperature characteristics are remarkably improved although the influence of the solid phase on the ionic conduction is limited.
Basic Performance of Tubular Molten Carbonate-Type Direct Carbon Fuel Cells
Authors: Ido Akifumi , Kawase Makoto
Published: September 2020

Direct carbon fuel cells (DCFCs) are expected to be useful devices that effectively utilize carbon resources. We have proposed novel tubular molten carbonate-type direct carbon fuel cells (TMC-DCFCs). In this study, basic performance of TMC-DCFCs such as influence of the difference in the cathode gas and fuel on the cell performance was investigated. I-V measurements and continuous power generation tests were conducted at 1073 K. It was shown that cell performance of TMC-DCFCs was improved by increase of O2/CO2 concentration in the cathode gas. When using carbonized wood as carbon fuel, high power density over 160 mW/cm2 was obtained as well as when using activated carbon. These results suggested that the change of the carbon/carbonate ratio is permissible to some extent and a small amount of ash hardly affects the cell performance.
Preparation and Electrochemical Properties of Ambient Temperature Molten Chlorides Based on Quaternary Ammonium Chloride and MgCl2
Authors: Matsumoto Hajime , Akai Naoto , Oyabu Rie
Published: September 2020

Magnesium metal can be used as reversible anode in a inorganic molten chloride such as alkali metal chloride, however, it is necessary to much decrease melting point of the chloride melts, to use a conventional battery components and materials in a magnesium battery. In this study, we would like to report an organic binary molten chloride based on N,N-Diethyl-N-Methyl- N-(2-methoxyethyl)ammonium chloride (DEMECl), and MgCl2, which melted near room temperature. The melting point of DEMECl (67°C) decreased with increasing amount of MgCl2. The lowest melting point of 34°C was obtained at MgCl2 - DEMECl (1:5). The physicochemical, thermal, and electrochemical properties were investigated.
Electrochemical Methods for Analysis of Hydroxide and Oxide Impurities in Li, Mg/Na, and Ca Based Molten Chloride Salts
Authors: Gonzalez Mario , Faulkner Emma , Zhang Chao , Choi Suhee , Simpson Michael Forrest
Published: September 2020

Due to their highly hygroscopic nature, molten chloride salts are known to resist complete thermal dehydration, resulting in incomplete water removal prior to use in high temperature applications. At temperatures required to melt these salts, this can result in hydrolysis, leading to formation of oxides or hydroxides. Depending on application, these hydrolytic impurities can cause further adverse effects through the formation of insoluble oxides and oxychlorides. In this paper, previously published work is reviewed to discuss electrochemical methods used for identification and measurement of hydrolytic impurities in LiCl and CaCl2 as well as their effect on electrolytic processes. Cyclic voltammetry shows that thermal dehydration of LiCl and CaCl2 promotes LiOH and CaO formation, respectively. The presence of CaO in a CaCl2-CeCl3 salt meant to emulate a typical actinide-chloride electrorefining salt causes insoluble Ce2O3 and CeClO to form, reducing electrochemical signals as the active species is precipitated as an insoluble phase.
Real-Time Monitoring for Electrochemical Analysis in Molten LiCl-KCl Eutectic Salt
Authors: Cha Han Lim , Park Jun Woo , Yun Jong-Il
Published: September 2020

In the present work, a real-time monitoring system for molten LiCl-KCl eutectic salt medium is set up with optically accessible quartz windows mounted on the furnace and the CMOS camera. Based on the designed system, the real-time monitoring was carried out to investigate the electrode behavior in various electrochemical systems, such as (1) differences in Co morphology deposited in molten CoCl2-LiCl-KCl system by various electrochemical deposition methods, (2) a reoxidation behavior of electrochemically reduced lithium, and (3) a reduction of Zr(IV) ions to Zr(III) ions in the molten ZrCl4-LiCl-KCl system. By delivering the video signal from the CMOS camera to the PC which controls the potentiostat, the visual changes can also be synced with the measured current or potential during the experiment. This enables us to compare the visualized morphological properties on the surface of the working electrode under different applied potential conditions during the application of electroanalytical methods.
Nucleation Study on Deposition of Aluminum from 1-Butyl-3-Methylimidazolium Chloride and Aluminum Chloride Ionic Liquid Electrolyte
Authors: Peng Yuxiang , Shinde Pravin , Reddy Ramana G.
Published: September 2020

The aluminum is electrodeposited from an ionic liquid comprising a eutectic mixture of 1-butyl-3-methylimidazolium chloride (BMIC) and aluminum chloride (AlCl3) at the AlCl3 mole fraction of 0.667 (molar ratio of 1:2). The electrochemical behavior of chloroaluminate species in the ionic liquid (IL) is investigated by the chronoamperometry (CA) technique at different temperatures. The diffusion coefficients (D) of Al2Cl7
– anion species in BMIC-AlCl3 IL are calculated at various temperatures based on the chronoamperometric method. The calculated number density of nucleation of Al deposits are 0.7 × 1010, 1.0 × 1010, and 1.4 × 1010 m-2 at 363 K with the applied potentials of -1.7, -1.75, and -1.8 V versus Pt, respectively. The scanning electron microscopy (SEM) result indicated that the calculated data is comparable to the experimental electrodeposition data. In addition, the rate of nucleation was also investigated during the electrodeposition experiment.
Electrochemical Behavior of Silver Halogenocomplexes in an Amide-Type Ionic Liquid
Authors: Serizawa Nobuyuki , Kuwahara Suguru , Katayama Yasushi
Published: September 2020

The electrochemical behavior of halogenocomplexes of Ag was investigated in an amide-type ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) in the presence of the corresponding halogen anion. Silver halides, AgX (X– = Cl–, Br–, and I–) were found to be soluble in BMPTFSA containing 0.5 M BMPX by forming [AgX3]2–. The cathodic reduction of [AgX3]2– to metallic Ag was possible within the electrochemical window of BMPTFSA. The reduction potentials were in the order of [AgCl3]2– > [AgBr3]2– > [AgI3]2–. The morphology of Ag deposits depended on the reduction potential. The diffusion coefficients of [AgCl3]2–, [AgBr3]2–, and [AgI3]2– were 2.5, 2.0, and 1.6 × 10–7 cm2 s–1, respectively. Formation of Ag nanoparticles dispersed in the ionic liquids was confirmed after potentiostatic cathodic reduction at –2.5 V using transmission electron microscopy.
Dissolution Behavior of SiO2 and Electrochemical Reduction of Dissolved SiO2 in Molten Chlorides
Authors: Ma Yuanjia , Yamamoto Takayuki , Yasuda Kouji , Nohira Toshiyuki
Published: September 2020

To develop a new production process for SOG-Si with high productivity and low energy consumption, the structure of silicate ions in molten eutectic NaCl–CaCl2 containing dissolved SiO2 was investigated by Raman spectroscopy. The existence of SiO3
2
− was indicated in melts containing 1.0 mol% of CaSiO3 (O2
−/SiO2 = 1.0). When 1.0 mol% of CaO was further added to the melt (O2
−/SiO2 = 2.0), the existence of SiO4
4
− was indicated. Cyclic voltammetry and potentiostatic electrolysis were conducted in molten NaCl–CaCl2 with different silicate ions. From cyclic voltammograms, XRD analysis, and SEM observation, silicate ions with different structure indicated different electrochemical reduction behavior; and the SiO3
2− ion is likely to be more suitable than SiO4
4− ion for the electrodeposition of Si.
Investigation on Operating Conditions Influencing the Aluminum Electrolysis Using Chloroaluminate Ionic Liquids
Authors: Ui Koichi , Kobayashi Satoshi , Takeguchi Tatsuya , Tsuda Tetsuya , Ueda Mikito , Nunomura Jyunji , Honkawa Yukio , Kojima Yoichi
Published: September 2020

AlCl3-EMIC (1-ethyl-3-methylimidazolium chloride) melt has attracted attention as an efficient electrolyte for Al electrolysis. However, several problems such as the low deposition rate and rough surface limit its practical use. In this study, we have investigated the influence of the electrolytic condition on the surface roughness of electrolytic Al foil by using the AlCl3-EMIC (molar ratio 2 : 1) melt with/without 20 mmol dm−3 of an OP (1,10-phenanthroline anhydrate) additive as an electrolyte. The AFM image revealed that the surface roughness (Sa) value of the electrolytic Al foil obtained on the Ti plate substrate from the melt with the OP additive at 50 ℃ was 45.8 nm at the current density of 52.6mA cm−2. A smooth electrolytic Al foil was found to be obtained even at high current density by increasing the operating temperature and adding OP to the melt.
Electroanalytical Study of Active Species to Deposit Ti Alloy from 1-Butyl-3-Methylimidazolium Chloride-Aluminum Chloride Ionic Liquid
Authors: Shinde Pravin , Peng Yuxiang , Reddy Ramana G.
Published: September 2020

The electrochemical behavior of titanium-chloroaluminate anion species in Lewis acidic 1-butyl-3-methylimidazolium chloride (BMIC)-aluminum chloride (AlCl3) ionic liquid (IL) electrolyte with 0.667 AlCl3 mole fraction is investigated at 383K by cyclic voltammetry (CV), chronoamperometry (CA), and chronopotentiometry (CP). The effect of scan rate on peak potential and peak current, constant current density, constant applied potential, and the electrolyte temperature are discussed. The redox reaction of the Ti2+/Ti0 deposition from titanium hepta-chloroaluminate ([Ti(Al2Cl7)4]2−) anions is a reversible process with a 2-electron transfer while that of Al3+/Al0 deposition from hepta-chloroaluminate ([Al2Cl7]−) anions is quasi-reversible with 3-electron transfer. The cyclic voltammograms indicated that the reduction of [Al2Cl7]− and [Ti(Al2Cl7)4]2− species to corresponding Al and Ti forms is a diffusion-controlled phenomenon. The diffusion coefficients (D) of the anion-species in BMIC-AlCl3 IL determined at 383 K using CV and CP methods are 9.74 × 10−10 m2 s−1 and 6.36 × 10−10 m2 s−1, respectively.
Synthesis of Refractory Metal Carbides on Carbon Fibers in Molten Salts and Their Electrochemical and Electrocatalytic Properties
Authors: Miklashov Dmitriy , Luneva Svetlana , Dolmatov Vladimir , Kuznetsov Sergey
Published: September 2020

TaC and NbC coatings and Mo2C crystals on the carbon fibers were obtained by the currentless transfer in molten salts. Investigation of electrocatalytic properties of these compositions in the reaction of the hydrogen peroxide decomposition was carried out. The kinetic parameters of this reaction were determined. It has been established that NbC on carbon fibers has a higher electrocatalytical properties in comparison with other carbides.
A Method of Producing Al–REE Master Alloys Using Exchange Reduction Reaction
Authors: Maksimtsev Konstantin V. , Mukhamadeev Andrey S. , Fofanov Grigoriy L. , Rebrin Oleg I. , Polovov Ilya B.
Published: September 2020

A novel method of aluminium-based master alloy manufacturing using high-temperature exchange processes between aluminium and halides of various rare-earth metals (Ce, Nd, Gd) was proposed. Samples with REE content from 1 to 10 wt. % were synthesised. The yields in excess of 90, 86, and 80% were achieved for Al–Ce, Al–Nd, and Al–Gd alloys, respectively. Microstructure of the alloys consisted of a metal matrix of aluminium in which intermetallic compounds were distributed. Mechanical properties of synthesised master alloys were determined.
Electrochemical Behavior of Titanium Complexes in the KCl-KF Melt with Additions of Alkaline Earth Metal Cations
Authors: Vetrova Daria A. , Kuznetsov Sergey
Published: September 2020

The charge transfer kinetics for the redox couple Ti(IV)/Ti(III) in the KCl-KF(10 wt.%)-K2TiF6 melt was studied. The standard rate constants of charge transfer (ks
) for the redox couple Ti(IV)/Ti(III) in the KCl-KF(10 wt.%)-K2TiF6 melt and the activation energy of charge transfer were calculated. Influence of strongly polarizing cations (Mg2+, Ca2+, Sr2+, and Ва2+) on the charge transfer kinetics was studied. It was determined the linear dependence of ks
on the ionic potential of alkaline earth metal cations. The activation energies of charge transfer in case of strongly polarizing cations addition were found.
Cationic Catalysis during the Discharge of Carbonate Anions in Molten Salts
Authors: Novoselova Inessa , Kuleshov Serhii Volodymyrovych , Omel'chuk Anatolii A , Soloviev Veniamin Vasilevich , Solovyova Natalia Veniaminovna
Published: September 2020

The paper presents a quantum-chemical model and experimental confirmation of cation catalysis mechanism during the cathodic discharge of carbonate anion in chloride melt. The model of cationized carbonate complex, which describes the effect of the acid-base properties of the melt on the electronic, energetic, structural, and electrochemical properties of the carbonate anion, was proposed. Cation-anion interaction between CO3
2- anion and the strongly polarizing cations (Li+, Ca2+, Mg2+) result either in the formation of cationized anions (metal complexes) or in anion dissociation. Dissociation of CO3
2- anions can occur directly or through an intermediate stage of formation of "short-lived" metal complexes. The changes in the electrochemical behavior of CO3
2- anion were studied by voltammetry by the sequential addition of cations with different polarizing (electrostatic) force to the Na,K,Rb|Cl eutectic. The potentiostatic electrolyses carried out in three electrolytes Na,K,Rb|Cl–Na2CO3–LiCl(CaCl2,MgCl2) at a same potential of -1.1 V against Ag/AgCl reference electrode gave a carbon powder.
Separation of Uranium and Zirconium in Alkali Chloride Melts Using Liquid Metal Cathodes
Authors: Volkovich Vladimir A. , Maltsev Dmitry S. , Soldatova Maria N. , Ryzhov Alexander A. , Ivanov Alexander B.
Published: September 2020

Cyclic voltammetry and cathodic polarization measurements were employed to study zirconium and uranium electrochemical behavior in LiCl–KCl eutectic based melts on solid (tungsten) and liquid (zinc, gallium, indium, Gz–Zn eutectic alloy) working electrodes. Deposition potentials of zirconium and uranium were determined. Ga–Zn alloy showed a difference of ca. 0.9 V in U and Zr deposition potentials. Thermodynamically achievable Zr/U separation factor in a “LiCl–KCl salt melt – liquid Ga–Zn alloy” system was experimentally determined.
Kinetics of Reaction of Oxygen with Uranium(IV) Chloride in Alkali Chloride Melts
Authors: Volkovich Vladimir A. , Ivanov Alexander B. , Ryzhov Alexander A. , Maltsev Dmitry S. , Griffiths Trevor R.
Published: September 2020

Reaction of oxygen with solutions of uranium tetrachloride in molten alkali chlorides was studied. The experiments were performed in LiCl–KCl, NaCl–KCl–CsCl, and NaCl–CsCl eutectic based melts at 450–750oC. Pure oxygen and argon–oxygen mixtures (containing ca. 1 and 10% O2) were used. Amount of oxygen passed through the melt varied from less than one to over 100 moles per mole of uranium present. In addition the reaction of oxygen with the melts containing a mixture of uranium(IV) and neodymium chlorides was investigated. The course of the reactions was followed by in situ electronic absorption spectroscopy measurements with the spectra recorded at the certain time intervals. Depending on temperature, cationic melt composition, and oxygen-to-uranium molar ratio, the reaction resulted in oxidation of uranium(IV) to soluble uranyl chloride and/or precipitation of uranium oxide. Analysis of the spectra provided the information on kinetics of U(IV) concentration change and the reaction rates were determined. Increasing temperature, O2 : U(IV) molar ratio or decreasing mean radius of alkali cations of the solvent melt resulted in faster decrease of U(IV) concentration in the melt.
Corrosion of Ceramic and Carbon-Based Materials in FLiNaK
Authors: Polovov Ilya B. , Abramov Aleksandr V. , Alimgulov Ruslan R. , Zolotarev Daniil A. , Gibadullina Alfiya F. , Trubcheninova Anastasiya I. , Volkovich Vladimir A. , Khotinov Vladislav A. , Zhilyakov Arkadiy Yu. , Belikov Sergey V.
Published: September 2020

Corrosion resistance of ceramic and carbon materials was studied in molten salt systems based on LiF–NaF–KF mixture in the temperature range 550–750°C. The rates of corrosion of silicon nitride, boron nitride, carbon-carbon composites, and high density graphite in the fluoride electrolyte were determined. The mechanisms of materials degradation after the contact with molten FLiNaK are proposed, and the effect of the salt media and the temperature on the mechanical properties of ceramic and carbon materials is considered.
Influence of Physicochemical Properties on Gas Transport Properties of Silver-Containing Ionic Liquid Mixtures for Olefin/Paraffin Membrane Separation
Authors: Park Sejoon , Freeman Benny D. , Brennecke Joan F.
Published: September 2020

Physicochemical properties, including viscosity and density, of silver salt-containing ionic liquids were measured and used to rationalize the permeability of ethane, ethylene, and helium through supported ionic liquid membranes (SILMs). Mixtures investigated included 1-hexyl-3-methylimidazolium bis(trifluoromethyl-sulfonyl)imide ([hmim][Tf2N]) and 1-hexyl-3-methylimidazolium nitrate ([hmim][NO3]) and their corresponding silver salts. The gas transport properties were very different for the two different ionic liquid/silver salt mixtures, consistent with very different behavior of viscosity and density upon silver salt dissolution. The distinctive dependence of both viscosity and density on temperature and silver salt concentration suggests different interion interactions and molecular arrangements in the two ionic liquids. Free volume and physical/chemical interactions between the anion and the gas solutes are critical in determining gas permeabilities.
Electrodeposition of Tantalum Coatings on Nitinol Stents
Authors: Kuznetsov Sergey , Makarova Olga , Dubrovskiy Anton
Published: September 2020

The electrodeposition of tantalum from the NaCl-KCl-NaF (5 wt. %)-K2TaF7 (10 wt. %) melt onto nitinol stents was investigated. The formation of several intermediate layers between the coating and substrate was found and their chemical composition was determined.
Quantum-Chemical Study of the Electron Transfer in CaTiF6+12CaCl2 Model System
Authors: Stulov Yuriy V. , Kremenetsky Vyacheslav G. , Kuznetsov Sergey A.
Published: September 2020

The electron transfer mechanism in titanium containing model system was investigated by quantum-chemical methods. The calculations were performed using the Firefly quantum-chemical package by methods of the density functional theory (DFT). The method of frontier molecular orbitals (FMO) has shown a good applicability for studying electron transfer in the CaTiF6+12CaCl2 model system. Structures with a high probability of the electron transfer from the cathode to the titanium complex were found. The analysis of systems both with a high-ordered and a low-ordered boundary layer was considered. Such an approach made it possible to reveal the values of boundary ions shift and compression of the Ti–F bonds, which describe the transition state. It was shown that the structure of the transition state is disordered compared with the initial structures. The structure of transition state corresponds to the actual state of the boundary layer near the electrode surface. Using the FMO method made it possible with a small amount of computer time to determine the structure of the transition state of the TiF6
2- complex near the electrode surface. The calculated activation energy of the electron transfer was in a good agreement with experimentally determined value.
Water Status on Micro/Nano Gap Between Galvanic Arrays and Flowing Current Around 100% in Relative Humidity
Authors: Terada Eiji , Sakamoto Yukihiro , Kawakita Jin
Published: September 2020

Dissimilar metal arrays with micron/nano gap detect water droplet and agglomerated molecules between them by galvanic action. At 100% in relative humidity (RH), dew condensation occurs on solid surface. The purpose of this study was to clarify the detection behaviour of the above-mentioned galvanic arrays around 100%RH and simultaneous measurement of galvanic current and observation of arrays and gap surface were carried out. Research results showed that the response current depended on RH owing to equilibrium of water molecules between vapor and adsorbed state on the sensor surface when RH increases up to 100%. At 100%RH, current showed steady value determined by balance between condensation of liquid water and evaporation of vapor. Once liquid water was formed on the sensor surface over 100%RH, the response current depended on the size of water determined kinetically. This dependence was observed during the decreasing process of the relative humidity over 100% and even under 100%.
Control of Heat Capacity of Moisture Sensor by Galvanic Arrays with Micro/Nano Gap
Authors: Kubota Yusuke , Satoh Norifusa , Sakamoto Yukihiro , Kawakita Jin
Published: September 2020

Occurrence of dew condensation depends on the surface temperature of the target. In order to adjust the temperature of the senor surface to that of the target, the temperature changing rate of the sensor surface was controlled by simply attaching heat sink to the backside of the sensor chip and by introducing thermal insulation around the backside of the sensor chip in this study. Experimental results demonstrated that the temperature change of the sensor surface was successfully relaxed against that of environment around the sensor surface and that the galvanic arrays with the micro/nano gaps on the sensor chip detected occurrence of dew condensation even under 100% in the relative humidity of environment. It is expected that the surface status of this sensor could be made closer to the target on application such as dew condensation detection.
Enhancement of Sensitivity Through Electrochemical Reaction Between Water and Micro/Nano Galvanic Arrays Towards Dew Condensation Prediction
Authors: Shrestha Rekha Goswami , Satoh Norifusa , Kawakita Jin
Published: September 2020

An enhancement in the detection sensitivity of microgalvanic cell termed as moisture sensor has been reported. It can detect condensed water, predict dew condensation and distinguish water droplet size with high accuracy and high speed by measuring galvanic current generated when a water droplet bridges Au and Al used as electrodes. Electrode reaction involved in a cell has been identified as cathodic O2 reduction. Coating the cathode, Au with a thin layer of Pt enhanced the cathodic reaction occurring at Pt/Au. SEM images of the surface of Pt coated Au confirmed an increase in homogenous coating of smaller Pt particles, with an increase in the thickness of Pt. This increased the active sites for the cathodic reaction, increasing the output current from the moisture sensor thus enhancing the sensitivity of a sensor.