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Search results for: HYDROGEN GENERATION
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NUMERICAL ANALYSIS OF SPECIES DIFFUSION AND METHANOL DECOMPOSITION IN THERMOCATALYTIC REACTOR BASED ON THE INTERMETALLIC PHASE OF Ni3Al FOR LOW REYNOLDS NUMBERS
PublicationNumerical modelling of hydrogen production by means of methanol decomposition in a thermocatalytic reactor using corrugated foil made of the Ni3Al intermetallic phase is shown in the paper. Experimental results of the flow analysis of mixtures containing helium and methanol in a thermocatalytic reactor with microchannels were used for the initial calibration of the CFD calculations (calculations based on the Computational Fluid...
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Investigating BiMeVOx compounds as potential photoelectrochemical and electrochemical materials for renewable hydrogen production
PublicationIn this study, BiMeVOx compounds (where Me: Co, Mo, Ce, Zr) were synthesized and characterized as potential photoelectrochemical materials for solar water splitting, the hydrogen evolution reaction (HER), and oxygen evolution reaction (OER). The analysis confirmed the successful formation of phase BiMeVOx compounds with the desired crystal structure. Among the tested materials, BiCoVOx(800) showed the highest photocurrent density...
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Molybdenum sulfide modified with nickel or platinum nanoparticles as an effective catalyst for hydrogen evolution reaction
PublicationIn this study, we investigate the catalytic performance of molybdenum sulfide (MoS2) modified with either nickel (Ni) or platinum (Pt) nanoparticles as catalysts for the hydrogen evolution reaction (HER). The MoS2 was prepared on the TiO2 nanotube substrates via a facile hydrothermal method, followed by the deposition by magnetron sputtering of Ni or Pt nanoparticles on the MoS2 surface. Structural and morphological characterization...
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Low-Barrier Hydrogen Bond Determines Target-Binding Affinity and Specificity of the Antitubercular Drug Bedaquiline
PublicationThe role of short strong hydrogen bonds (SSHB) in ligand-target binding remains largely unexplored, thereby hin- dering a potentially important avenue in the rational drug de- sign. Here, we investigate the interaction between bedaquiline (Bq), a potent anti-tuberculosis drug, and the mycobacterial ATP synthase, to unravel the role of a specific hydrogen bond to a conserved acidic residue in the target affinity and specificity....
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Absorptive Desulfurization of Model Biogas Stream Using Choline Chloride-Based Deep Eutectic Solvents
PublicationThe paper presents a synthesis of deep eutectic solvents (DESs) based on choline chloride (ChCl) as hydrogen bond acceptor and phenol (Ph), glycol ethylene (EG), and levulinic acid (Lev) as hydrogen bond donors in 1:2 molar ratio. DESs were successfully used as absorption solvents for removal of dimethyl disulfide (DMDS) from model biogas steam. Several parameters affecting the absorption capacity and absorption rate have been...
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Interplay between Aryl···Perfluoroaryl and Hydrogen Bonding Interactions in Cocrystals of Pentafluorophenol with Molecules of Trigonal Symmetry
PublicationCocrystals of seven star-shaped triaryl compounds with pentafluorophenol (pfp) were prepared and structurally characterized by the single-crystal X-ray diffraction method. Cocrystallization of pfp with planar (or almost planar) compounds gave six 3:1 molecular complexes with well-defined layered structures. The layers are composed of alternating pfp3 trimers, linked by hydrogen bonding, and triaryl molecules held together in planes...
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Effect of choline chloride based natural deep eutectic solvents on aqueous solubility and thermodynamic properties of acetaminophen
PublicationIn this work, natural deep eutectic solvents (NADESs) containing choline chloride as hydrogen bond acceptor and 1,2-propanediol, malic acid and tartaric acid as hydrogen bond donors have been synthesized and applied to enhance the aqueous solubility of model sparingly water-soluble drug – acetaminophen. The results indicate that the greatest impact on the solubility of acetaminophen have deep eutectic solvents based on 1,2-propanediol...
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EFFECT OF ANTIOXIDANTS ON THE STABILITY OF PITCH- BASED POLYMER TO THERMO-OXIDATIVE ACTION
PublicationThe influence of stabilizers – hydrogen donors – on the processes of thermooxidative destruction of pitch-based polymer has been investigated. It is shown that Irganox has not stabilizing effect on pitch-based polymer and melamine slightly retards the destructive process. A mixture of melamine and Irganox exhibits synergetic stabilizing effect and at the optimum ratio it can be used to prevent unwanted thermooxidative processes...
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Why the Solvation Water around Proteins Is More Dense than Bulk Water
PublicationThe main aim of this work is to propose a rational explanation of the commonly observed phenomenon of increasing water density within solvation shell of proteins. We have observed that the geometry of the water–water hydrogen bond network within solvation layer differs from the one in bulk water, and it is the result of interactions of water molecules with protein surface. Altered geometry of the network reflects changes in the...
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Why the solvation water around proteins is more dense than bulk water
PublicationThe main aim of this work is to propose a rational explanation of commonly observed phenomenon of increasing water density within solvation shell of proteins. We have observed that geometry of the water-water hydrogen bond network within solvation layer differs from the one in bulk water and it is the effect of interactions of water molecules with protein surface. Altered geometry of the network reflects changes in the structure...
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Effect of Some Sulphur Additives on The Degradation of 9Cr-1Mo Steel After Its 10 Years Service in The CCR Platforming Unit
PublicationThe work shows the results of the tests of 9Cr-1Mo steel, which was for 10 years operated in the CCR platforming unit in Group Lotos SA in Gdańsk, and then in the laboratory was sulphidised during 166 h at a temperature of 600 °C. Sulphidation was performed in a mixture of H2-H2S gases at the vapour pressure of sulphur 4.1·10-14 atm, so the order of magnitude of vapour pressure was less than that of the dissociation pressure of...
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Deep eutectic solvents based highly efficient extractive desulfurization of fuels – Eco-friendly approach
PublicationThe developed process is based on alternative, green and cheap solvents for efficient desulfurization of fuels. Several deep eutectic solvents (DESs) were successfully synthesized and studied as extraction solvents for desulfurization of model fuel containing thiophene (T), benzothiophene (BT) and dibenzothiophene (DBT). The most important extraction parameters (i.e. kind of DES, DES: fuel volume ratio, hydrogen bond acceptor:...
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Effective degradation of sulfide ions and organic sulfides in cavitation-based Advanced Oxidation Processes (AOPs)
PublicationThe paper presents the results of investigations on the effectiveness and reaction rate constants of the oxidation of sulfide ions and organic sulfides in real industrial effluents from the production of bitumens (2000 mg S2- L-1) using hydrodynamic and acoustic cavitation. The content of the effluents was analysed in terms carbon disulfide, dimethyl sulfide, and di-tert-butyl disulfide concentration. A possibility of complete...
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Synthesis and hydrogen evolving catalysis of a panchromatic photochemical molecular device
PublicationA dinuclear hydrogen evolution photocatalyst [(tbbpy)2Os(tpphz)PtI2](PF6)2 (tbbpy = 4,4′-tert-butyl-2,2′-bipyridine; tpphz = tetrapyrido[3,2-a:2′,3′-c:2′′,3′′-h:2′′′,3′′′-j]phenazine) is synthesized in order to make use of the broader range of visible light absorption mitigated by the osmium center. In a first step, the activity of the complex for hydrogen evolution is investigated by evaluating the role of different electron donors...
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Deep Eutectic Solvents or Eutectic Mixtures? Characterization of Tetrabutylammonium Bromide and Nonanoic Acid Mixtures
PublicationDeep eutectic solvents have quickly attracted the attention of researchers because they better meet the requirements of green chemistry and thus have the potential to replace conventional hazardous organic solvents in some areas. To better understand the nature of these mixtures, as well as expand the possibilities of their use in different industries, a detailed examination of their physical properties, such as density, viscosity,...
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Stabilization of N-, N,N-, N,N'-Methylated and Unsubstituted Simple Amidine Salts by Multifurcated Hydrogen Bonds
PublicationIn the light of the usefulness of amidines in medicinal chem., this paper considers the effects on biol. properties and chem. reactivities of org. mols. affected by intramol. interactions. The study of chem. shifts has been an important source of information on the electronic structure of amidine salts and their ability to form non-covalent bonds with nucleic acids. The NMR and IR results demonstrate that hydrogen bonds are...
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Preparation and Characterization of Films Based on Disintegrated Bacterial Cellulose and Montmorillonite
PublicationThe food packaging materials from natural polymers including polysaccharides offer an ecologically important alternative to commonly used synthetic, non-biodegradable counterparts. The purpose of this work was to modify of bacterial cellulose (BC) leading to the improvement of its functional properties in terms of use as a food packaging material. Effects of disintegration of BC and addition of montmorillonite (MMT) on its water...
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The impedance of hydrogen oxidation reaction in a proton exchange membrane fuel cell in the presence of carbon monoxide in hydrogen stream
PublicationEvaluation of performance of a proton exchange membrane fuel cell, which is affected by carbon monoxide that pollutes the hydrogen stream, was presented. This influence was studied for carbon monoxide concentration of 125–325 ppb, which are close to values specified in ISO 14687:2019 standard. Performed studies provided crucial information for further development of fuel cell as an energy source for automotive application. Impedance...
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Correlation between partial inhibition of hydrogen evolution using thiourea and catalytic activity of AB5-type hydrogen storage alloy towards borohydride electrooxidation
PublicationDirect borohydride fuel cells (DBFCs) are devices which directly convert the chemical energy stored in the borohydride ion and oxidant into electrical energy as a result of redox reactions. Unfortunately, a significant amount of fuel is lost as a result of the undesirable hydrolysis reaction. The selection of an efficient borohydride hydrolysis inhibitor requires detailed knowledge regarding the interaction mechanism between the...
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Extractive detoxification of feedstocks for the production of biofuels using new hydrophobic deep eutectic solvents – Experimental and theoretical studies
PublicationThe paper presents a synthesis of novel hydrophobic deep eutectic solvents (DESs) composed of natural components, which were used for removal of furfural (FF) and 5-hydroxymethylfurfural (HMF) from lignocellulosic hydrolysates. The main physicochemical properties of DESs were determined, followed by explanation of the DES formation mechanism, using 1H NMR, 13C NMR and FT-IR analysis and density functional theory (DFT). The most...
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Nanotechnologies in Development of Structural Materials and Biomaterials
PublicationThe nanometric materials and technologies resulted in nanostructures are reviewed. The examples of nanomaterials are shown. The typical nanotechnologies, including plastic deformation, mechanical attrition, controlled detonation, hot plasma jet synthesis, laser vaporisation, CVD and PVD, mechanical milling, annealing, ultrasonic irradiation, nanolithography, electrocrystallisation, electrospinning, sol-gel method, cryogenic laser-enhanced...
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High temperature corrosion and corrosion protection of porous Ni22Cr alloys
PublicationIn this work corrosion kinetics of the porous IN625 alloy is studied in the temperature range of 700 °C – 800 °C in air and humidified hydrogen for up to 1000 hours. Moreover, an effective and simple method of reducing corrosion rates of porous alloys by the infiltration of the rare earths elements is shown. Modification by the yttrium containing precursor reduces the corrosion rate by a factor of 50 in air at 700 °C so that the...
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Simultaneous impedance and volumetric studies and additionally potentiodynamic polarization measurements of molasses as a carbon steel corrosion inhibitor in 1M hydrochloric acid solution
PublicationThe inhibition effect of molasses on the corrosion of low carbon steel in 1M hydrochloric acid solution was investigated by volumetric and electrochemical measurements. Potentiodynamic polarization and dynamic electrochemical impedance spectroscopy (DEIS) results were obtained and compared with to those, obtained with the hydrogen evolution technique. All results indicate that molasses functioned as a good inhibitor in 1M hydrochloric...
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Crystal Structure of N-(2-Benzoyl-4,5-dimethoxyphenethyl)-2-phenylacetamide
PublicationThe crystal structure of N-(2-benzoyl-4,5-dimethoxyphenethyl)-2-phenylacetamide indicates that the compound crystallizes in the monoclinic C2/c space group with eight molecules in the unit cell. The heteroatoms from the amide group form a chain of intermolecular N-H ··· O hydrogen bonds propagating along the b axis. The carbonyl group from the benzoyl substituent participates in short contacts with two H-atoms from the ethyl or...
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Molecular hydrogen solvated in water – A computational study
PublicationThe aqueous hydrogen molecule is studied with molecular dynamics simulations at ambient temperature and pressure conditions, using a newly developed flexible and polarizable H2 molecule model. The design and implementation of this model, compatible with an existing flexible and polarizable force field for water, is presented in detail. The structure of the hydration layer suggests that first-shell water molecules accommodate the...
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Study of the Anti-Staphylococcal Potential of Honeys Produced in Northern Poland
PublicationThe antimicrobial activity of 144 samples of honeys including 95 products from apiaries located in Northern Poland was evaluated. The antibacterial activity of those natural products, their thermal stability, and activity in the presence of catalase was investigated by microdilution assays in titration plates. The MTT assay was performed for the determination of anti-biofilm activity. Spectrophotometric assays were used for the...
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Physical crosslinking of hyaluronic acid in the presence of phospholipids in an aqueous nano-environment
PublicationHyaluronic acid and phospholipids are two components in the synovial joint cavity that contribute to joint lubrication synergistically. Molecular dynamics simulations were performed and hydrogen bonds in hyaluronic acid were analyzed to identify specific sites that are responsible for its physical cross-linking. Two molecular masses of hyaluronic acid, 10 kDa and 160 kDa, were considered. We use molecular dynamics simulations and...
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Enhanced boron doping of thin diamond films grown in deuterium-rich microwave plasma
PublicationThe boron-doped diamond thin films were growth in deuterium rich microwave plasma in CVD process. The mechanism of influence of plasma composition on boron doping level was studied using optical emission spectroscopy. Deuterium rich plasma results in an increased dissociation of B2H6 precursor and intense boron-radicals' production. In consequence, a higher doping level of diamond films was observed by means of Laser Induced Breakdown...
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Hydrophobic deep eutectic solvents in microextraction techniques–A review
PublicationOver the past decade, deep eutectic solvents (DES) have been widely studied and applied in sample preparation techniques. Until recently, most of the synthesized DES were hydrophilic, which prevented their use in the extraction of aqueous samples. However, after 2015 studies on the synthesis and application of hydrophobic deep eutectic solvents (HDES) has rapidly expanded. Due to unique properties of HDES i.e. density, viscosity,...
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Hyaluronan-Chondroitin Sulfate Anomalous Crosslinking Due to Temperature Changes
PublicationGlycosaminoglycans are a wide class of biopolymers showing great lubricating properties due to their structure and high affinity to water. Two of them, hyaluronic acid and chondroitin sulfate, play an important role in articular cartilage lubrication. In this work, we present results of the all-atom molecular dynamics simulations of both molecules placed in water-based solution. To mimic changes of the physiological conditions,...
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Computational Study of Molecular Interactions in ZnCl2(urea)2 Crystals as Precursors for Deep Eutectic Solvents
PublicationDeep eutectic solvents (DESs) are now enjoying an increased scientific interest due to their interesting properties and growing range of possible applications. Computational methods are at the forefront of deciphering their structure and dynamics. Type IV DESs, composed of metal chloride and a hydrogen bond donor, are among the less studied systems when it comes to their understanding at a molecular level. An important example...
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Storage of High-Strength Steel Flux-Cored Welding Wires in Urbanized Areas
PublicationThe condition of the consumables is a key factor determining the waste reduction in the welding processes and the quality of the welded joint. The paper presents the results of tests of four types of fux-cored wires dedicated for welding high-strength steels, stored for 1 month and 6 months in Poland in two urbanized areas: in a large seaside city (Gdańsk) and in Warsaw, located in the center of the country. The wires were subjected...
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A novel (Ti/Ce)UiO-X MOFs@TiO2 heterojunction for enhanced photocatalytic performance: Boosting via Ce4+/Ce3+ and Ti4+/Ti3+ redox mediators
PublicationTitanium-substituted cerium-oxo-based UiO MOFs with terephthalate linkers modified by various groups (–Br, –NH2, –NO2) or their derivatives (N-heterocyclic or biphenyl groups) were combined with titanium dioxide in a multistep route to obtain a core-shell-like architecture. DFT simulations showed that Ce- and bimetallic Ti/Ce- MOFs exhibited different charge compensation. Extended characterization revealed the formation of heterojunctions between...
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Experimental and predicted physicochemical properties of monopropanolamine-based deep eutectic solvents
PublicationIn this work, the novel deep eutectic solvents (DESs) based on 3-amino-1-propanol (AP) as hydrogen bond donor (HBD) and tetrabutylammonium bromide (TBAB) or tetrabutylammonium chloride (TBAC) or tetraethylammonium chloride (TEAC) as hydrogen bond acceptors (HBAs) were synthesized with different molar ratios of 1:4, 1:6 and 1:8 salt to AP. Fourier Transform Infrared Spectroscopy measurements were performed to provide an evidence...
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Influence of Annealing Atmospheres on Photoelectrochemical Activity of TiO2 Nanotubes Modified with AuCu Nanoparticles
PublicationIn this article, we studied the annealing process of AuCu layers deposited on TiO2 nanotubes (NTs) conducted in various atmospheres such as air, vacuum, argon, and hydrogen in order to obtain materials active in both visible and UV–vis ranges. The material fabrication route covers the electrochemical anodization of a Ti plate, followed by thin AuCu film magnetron sputtering and further thermal treatment. Scanning electron microscopy...
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Experimental and predicted physicochemical properties of monopropanolamine-based deep eutectic solvents
PublicationIn this work, the novel deep eutectic solvents (DESs) based on 3-amino-1-propanol (AP) as hydrogen bond donor (HBD) and tetrabutylammonium bromide (TBAB) or tetrabutylammonium chloride (TBAC) or tetraethylammonium chloride (TEAC) as hydrogen bond acceptors (HBAs) were synthesized with different molar ratios of 1: 4, 1: 6 and 1: 8 salt to AP. Fourier Transform Infrared Spectroscopy measurements were performed to provide an evidence...
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Method of sacrificial anode dual transistor-driving in stray current field
PublicationIn order to control a magnesium anode in a stray current interference field, a dual transistor driving system has been proposed. It consisted of a combination of PNP and NPN transistors. Dual transistor driven system and direct anode to cathode connection were electrochemically tested in 3% NaCl solution. The dual transistor driven system increased the anode efficiency and reduced hydrogen evolution and the risk of embrittlement....
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Hydrogen migration observed in fragmentation of the pyridine molecules in collisions with the H+, H2+, He+and He++cations
PublicationThe hydrogen atom migration preceding fragmentation of the pyridine molecules by the H+, H2+, He+ and He++ collisions has been investigated in the 5-2000 eV energy range. The pyridine molecule structure is lacking of the NH group, thus formation of the NH radicals is an evidence of the H atom relocation prior to the cation-induced fragmentation. The NH(A3Π) fragmentation yields measured by detecting its A3Π→X3Σ− fluorescence show...
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The properties of reduced Ge-Sb-O glasses for thermoelectric devices
PublicationThe structural and electrical properties of germanium-antimonate glasses after heat treatment in hydrogen have been determined. In the case of 50GeO2-50Sb2O3 glass reduced at 340°C even for less than 1 hour a continuous layer of antimony granules is formed and its electrical properties determine the surface conductivity of the reduced sample. The bulk electrical conductivity at 100°C of this sample was determined as 1000 Scm-1...
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Synthesis and Testing of BCZY/LNZ Mixed Proton–electron Conducting Composites for Fuel Cell Applications
PublicationA composite of BaCe0.6Zr0.2Y0.2O3–δ and Li2O:NiO:ZnO was investigated for fuel cell applications. The composite was successfully synthesized and its phase stability was confirmed at temperatures up to 900 °C. The influence of sintering and pressing aids on density was also investigated. Electrical properties were measured. DC electrical conductivity was about 8•10-4 S/m at 845 K. Open circuit voltage measurements in wet hydrogen...
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Electron Scattering on X(CH3)4 Molecules: Applicability of Simple Additivity Rule and Role of Methylation
PublicationTo investigate influence of target methylation (substitution of a hydrogen atom by methyl group) on electron-collision processes we compare absolute total cross sections for XH4 and X(CH3)4 molecules, where X is Si and Ge, respectively. We also compare experimental TCSs energy dependencies with estimated data obtained using simple formula and TCSs for methyl group and those for SiH4 and GeH4. Electron-scattering TCSs for mentioned...
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Electrical properties of Y0.08Sr0.92Ti0.92Nb0.08O3-δ after reduction in different reducing conditions
PublicationElectrical properties of perovskite Y0.08Sr0.92Ti0.92Nb0.08O3−ı after reduction in different conditions were studied. Relatively high electrical conductivity in samples reduced in ammonia was observed. The conductivity of Y0.08Sr0.92Ti0.92Nb0.08O3−ı reduced in ammonia at 1500 ◦C was of about 600 S/cm at 200 ◦C. Conductivity after reduction in ammonia at 1500 ◦C was stable both in hydrogen and oxygen atmosphere up to 600 ◦C. Reduction...
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Method of sacrificial anode transistor-driving in cathodic protection system
PublicationA magnesium anode driving system has been proposed. A PNP driving transistor has been used. Electrochemical testing in 3%NaCl, results and comparison of the driving system and classic direct anode to cathode connection are presented. The driving system reduced the protection current and stabilized the working conditions of the anode. Higher anode efficiency was achieved. Overprotection and hydrogen embrittlement threats were prevented...
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Factors causing degradation of sulfadimetoxine
PublicationSulfadimetoxine is a representative of sulfonamide drugs which presence inhibits growth of activated sludge bacteria, rhat is necessary for the effective mineralization of organic and inorganic contaminants. Therefore factors which con prevent this situation are searched. Aim of this study is selection of conditions causing efficien degradation of the drug- sulfadimetoxine. The impact of such aspects as : the type of oxidizing...
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A General Synthesis of Diaryl Cyclic Diamidines
PublicationA convenient and general method has been developed for directly converting bis-nitriles, e.g., I, to cyclic diamidines, e.g., II, using reagents derived from diaminoalkanes, e.g., H2NCH2CH2NH2, satd. with hydrogen sulfide. A 1:1 mixt. of a diaminoalkane and Et alc. (or without) was effective in most cases (72-88%). The synthetic utility of this methodol. in the prepn. of tetrakis(cyclic amidino)pyrenes III (R = H, Me) from 1,3,6,8-tetracyanopyrene...
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EFFECT OF SURFACE STATE AND STRESS ON AN OXIDATION OF THE ZIRCALOY-2 ALLOY
PublicationZr alloys are widely used as materials for nuclear fuel pellets in the nuclear industry. In the case of the LOCA or RIA happen, a temperature may locally reach high values. Even if the high temperature maintains shortly, the zirconium oxides may become permeable, absorb hydrogen appearing in cooling water from decomposition reaction and crack because of formation and brittle failure of hydrides. Such model cannot so far take into...
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The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c, d, or e mimics
PublicationBacteriochlorophylls (BChls) c, d, and e are the main light-harvesting pigments of green photosynthetic bacteria that self-assemble into nanostructures within the chlorosomes forming the most efficient antennas of photosynthetic organisms. All previous models of the chlorosomal antennae, which are quite controversially discussed because no single crystals could be grown so far from these organelles, involve a strong hydrogen-bonding...
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Communication: Inside the water wheel: Intrinsic differences between hydrated tetraphenylphosphonium and tetraphenylborate ions
PublicationTetraphenylphosphonium tetraphenylborate (TPTB) is a common reference electrolyte in physical chemistry of solutions allowing for a convenient partitioning of thermodynamic properties into single-ion contributions. Here, we compute on the basis of ab initio molecular dynamics simulations the infrared (IR) spectra for hydrated constituent ions of the TPTB assumption. Using spectral decomposition techniques, we extract important...
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Combined effect of nitrogen-doped carbon and NiCo2O4 for electrochemical water splitting
PublicationElectrocatalytic water splitting for green hydrogen production necessitates effective electrocatalysts. Currently, commercial catalysts are primarily platinum-based. Therefore, finding catalysts with comparable catalytic activity but lower cost is essential. This paper describes spinel-structured catalysts containing nickel cobaltite NiCo2O4, graphene, and additionally doped with heteroatoms. The structure and elemental composition...
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Plasticity of Bead-On-Plate Welds Made with the Use of Stored Flux-Cored Wires for Offshore Applications
PublicationExtreme atmospheric conditions in the marine and offshore industry are harmful to engineering materials, especially to welded joints, and may cause degradation of their properties. This article presents the results of research on the plasticity of bead-on-plate welds made using two types of seamless, copper plated flux-cored wires. Before welding, spools with wire were stored for 1 month in two distinct locations with different...