Journal articles on the topic 'Sieverts constant'
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Pomella Lobo, Tiago, Ester Diaz-Alvarez, and Laëtitia Frances. "A Model to Simulate Gas Dissolution into/through Metals and Its Application to Deuterium in a 316L Steel Chamber with Pb-Li in a Quasi-2D Geometry." Applied Sciences 12, no. 5 (February 28, 2022): 2523. http://dx.doi.org/10.3390/app12052523.
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Liquid lead-lithium in eutectic proportions (Pb-Li) is a candidate material for Breeding Blankets (BBs) in future Fusion Power Plants (FPP). BB design depends on the diffusivity and Sieverts’ constant (solubility) of tritium in this alloy, but literature reports a large scattering of measurements for these values. A model was developed to address one possible source of this scattering in static experiments, i.e., non-negligible loss of hydrogen gas through steel walls of containers. This model simulates the dissolution of gases into, and their diffusion through, metallic barriers for diffusivity and Sieverts’ constant as inputs. When implemented, it can be used to compute the pressure decrease in a metallic chamber, and comparison of simulated curves with experimental ones allows for estimates of the diffusivity and Sieverts’ constant. This approach was used to estimate these coefficients for deuterium in stainless steel, using experiments performed with a 316L steel chamber from an existing facility (the Vacuum Sieve Tray setup) and simulations in a quasi-2D representation of this chamber. This validated the model, which was then used to simulate the chamber containing Pb-Li, as a means of planning for future experiments.
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Bolʼshov, L. A., S. K. Korneichuk, and E. L. Bolʼshova. "Thermodynamics of nitrogen solutions in liquid nickel." Izvestiya. Ferrous Metallurgy 64, no. 3 (April 9, 2021): 200–204. http://dx.doi.org/10.17073/0368-0797-2021-3-200-204.
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The simplest model of the structure and interatomic interaction is applied to nitrogen solutions in liquid alloys of Fe – Ni system, which earlier (2019) was used by the authors for nitrogen solutions in alloys of Fe – Cr system. The principles of statistical mechanics are used in this model. Thus, three formulas were obtained. The first formula expresses the Sieverts law constant for the solubility of nitrogen in liquid nickel through a similar constant for the solubility of nitrogen in liquid iron and the Wagner interaction coefficient of nitrogen with nickel in low-concentration liquid iron-base alloys. The second formula expresses the partial enthalpy of dissolution of nitrogen in liquid nickel during the formation of an infinitely dilute solution through a similar value for dissolution of nitrogen in liquid iron and the Wagner interaction coefficient of nitrogen with nickel in iron-base liquid alloys. The third formula expresses the Wagner interaction coefficient of nitrogen with iron in low-concentration liquid nickel-base alloys through the Wagner interaction coefficient of nitrogen with nickel in liquid iron-base alloys. The constant of the Sieverts law for the solubility of nitrogen in liquid iron at T = 1873 K is assumed to be 0.044 mass. %. The partial enthalpy of dissolution of nitrogen in liquid iron assumed to be 5.0 kJ/mol. For Wagner interaction coefficient of nitrogen with nickel in iron-base liquid alloys at 1873 K three variants of values were studied: 2.4, 2.6, and 2.85. For the first option, theoretical value of the Sieverts law constant for solubility of nitrogen in liquid nickel at T = 1873 K, equal to 0.00195 mass. % was obtained. Theoretical value of the enthalpy of dissolution of nitrogen in liquid nickel is 52.7 kJ/mol. Theoretical value of the Wagner interaction coefficient of nitrogen with iron in nickel-base liquid alloys is –4.0. The agreement of theory with experiment seems to be satisfactory.
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Priester, F., R. Größle, N. Bekris, and I. Cristescu. "A new facility for the measurement of the Sieverts’-constant for PbLi with tritium." Fusion Engineering and Design 191 (June 2023): 113568. http://dx.doi.org/10.1016/j.fusengdes.2023.113568.
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Bystrzycki, J., T. Czujko, R. A. Varin, and Jaroslaw Mizera. "The Effect of Milling Mode on the Hydriding Properties of Nanocrystalline Mg2Ni." Solid State Phenomena 99-100 (July 2004): 137–42. http://dx.doi.org/10.4028/www.scientific.net/ssp.99-100.137.
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The paper presents the results of studies of the hydrogen sorption properties of nanocrystalline Mg2Ni intermetallic prepared by mechanical (ball) milling under controlled shearing/impact mode. The pre-alloyed intermetallic powders were subjected to ball milling under various controlled milling conditions such as shearing, high-energy shearing and impact in a magnetic Uni-Ball-Mill 5. The hydriding properties were evaluated by monitoring the absorption PC isotherms by the conventional constant-volume method using Sieverts semi-automatic apparatus. Changes of structure during processing and hydriding properties of nanostructured Mg2Ni intermetallic powders are shown and discussed.
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Lim, Jun, Manfredi Gabriele, Alessandro Marino, Kristof Gladinez, and Alexander Aerts. "Electrochemical Measurement of Sieverts’ Constant and Solubility of Oxygen in LBE at 598–748 K." Journal of The Electrochemical Society 164, no. 12 (2017): H743—H747. http://dx.doi.org/10.1149/2.0231712jes.
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Bol’shov, L. A., and S. K. Korneichuk. "THERMODYNAMICS OF LIQUID NITROGEN SOLUTIONS IN CHROMIUM." Izvestiya. Ferrous Metallurgy 62, no. 5 (June 19, 2019): 387–93. http://dx.doi.org/10.17073/0368-0797-2019-5-387-393.
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A simple theory of thermodynamic properties of liquid nitrogen solutions in Fe – Cr alloys is proposed based on lattice model of the considered solutions. The model assumes a FCC lattice. In the sites of this lattice are the atoms of Fe and Cr. Nitrogen atoms are located in octahedral interstices. The nitrogen atom interacts only with the metal atoms located in the lattice sites neighboring to it. It is assumed that the energy of this interaction depends neither on the composition nor on the temperature. It is supposed that the solution in the Fe – Cr system is perfect. Within the framework of the proposed theory, a relation is obtained that expresses the value of the Sieverts law constant for solubility of N in liquid Cr through the similar constant for the solubility of N in liquid Fe and the Wagner N – Cr interaction coefficient in liquid Fe. A relation is also obtained to express the partial enthalpy of nitrogen dissolution in liquid Cr through the similar quantity for N in liquid Fe and Wagner N – Cr interaction coefficient in liquid Fe. A formula is deduced that establishes a connection between the Wagner N – Fe interaction coefficient in liquid Cr and N-Cr interaction coefficient in liquid Fe. Using the formulas obtained, value of the Sieverts law constant for the solubility of nitrogen in liquid Cr, the enthalpy of dissolution of N in liquid Cr and value of the Wagner N – Fe interaction coefficient in liquid Cr extrapolated to a temperature of 1873 K are calculated. The calculation results are compared with results of the experimental study of nitrogen solubility in liquid Cr carried out by different researchers using different methods. The theory results are in the best agreement with experimental data obtained by the sampling method. Values of the Wagner N – N interaction coefficient in liquid Cr and liquid Fe are discussed.
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Esteban, G. A., A. Perujo, and F. Legarda. "Study of the Isotope Effects in the Hydrogen Transport in Polycrystalline Tungsten." Materials Science Forum 480-481 (March 2005): 537–42. http://dx.doi.org/10.4028/www.scientific.net/msf.480-481.537.
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A time-dependent gas-phase isovolumetric desorption technique has been used to evaluate the diffusive transport parameters of hydrogen isotopes in polycrystalline tungsten in the temperatures range 673 to 1073 K and driving pressures from 1.3 104 to 105 Pa. Experiments have been run with both protium and deuterium obtaining their respective transport parameters diffusivity (D), Sieverts’ constant (Ks), the trap site density (Nt) and the trapping activation energy (Et). Isotope effects on these transport parameters are analysed and modelled. Because the classical isotope relation for diffusivity has not been fulfilled, quantum-statistical vibration theory has been applied to model the isotopic relation. A congruent isotopic variation of diffusion parameters related to the type of microstructure, bcc, has been confirmed.
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Suzuki, Asuka, and Hiroshi Yukawa. "A Review for Consistent Analysis of Hydrogen Permeability through Dense Metallic Membranes." Membranes 10, no. 6 (June 10, 2020): 120. http://dx.doi.org/10.3390/membranes10060120.
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The hydrogen permeation coefficient (ϕ) is generally used as a measure to show hydrogen permeation ability through dense metallic membranes, which is the product of the Fick’s diffusion coefficient (D) and the Sieverts’ solubility constant (K). However, the hydrogen permeability of metal membranes cannot be analyzed consistently with this conventional description. In this paper, various methods for consistent analysis of hydrogen permeability are reviewed. The derivations of the descriptions are explained in detail and four applications of the consistent descriptions of hydrogen permeability are introduced: (1) prediction of hydrogen flux under given conditions, (2) comparability of hydrogen permeability, (3) understanding of the anomalous temperature dependence of hydrogen permeability of Pd-Ag alloy membrane, and (4) design of alloy composition of non-Pd-based alloy membranes to satisfy both high hydrogen permeability together with strong resistance to hydrogen embrittlement.
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von der Weth, Axel, Frederik Arbeiter, Dmitry Klimenko, Volker Pasler, and Georg Schlindwein. "Permeation Data Analysis Considering a Nonzero Hydrogen Concentration on the Low Pressure Detector Side for a Purged Permeation Experiment." Defect and Diffusion Forum 391 (February 2019): 18–29. http://dx.doi.org/10.4028/www.scientific.net/ddf.391.18.
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Currently available diffusion constant and Sieverts constant experimental results are based on time dependent permeation experiments. The common principle is an analysis which is expecting that the permeating hydrogen is “transported” from the retentate chamber to the permeate chamber through the connecting membrane, with a vanishing hydrogen partial pressure on the permeate side. But reality shows a different behaviour caused by the fact that a nonzero hydrogen partial pressure in the permeate chamber is necessary for detection purposes. This nonzero pressure is mostly not considered by analysis. This issue is solved (approximatively) numerically by the procedure as described in this paper. This work is rooted in the field of fusion research, where so called purge gas with low partial pressure of tritium is contacting the structural materials (300-550°C) of the fusion reactor (blanket) and of process equipment, where the tritium losses are of interest. The developed algorithms are intended for the evaluation of an experiment termed “Q-PETE” (Q for any hydrogen isotope, PEermeation Transport Experiment), which abstracts the hydrogen transport conditions of the fusion blanket, and where the effect of nonzero hydrogen concentration on the permeate side is relevant. The algorithms are useful for all experiments, where the ratio of hydrogen pressures between retentate and peremeate side are far from infinite.
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von der Weth, Axel, Frederik Arbeiter, Kaori Nagatou, Volker Pasler, Dmitri Klimenko, and Marvin Schulz. "Numerical Analysis of an Isovolumetric Thermal Desorption Experiment." Diffusion Foundations 27 (May 2020): 122–35. http://dx.doi.org/10.4028/www.scientific.net/df.27.122.
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Our research group is currently investigating a new kind of thermal desorption experiment (TDE), which uses a hydrogen isotope by loading-unloading process yielding transport parameters. Safety issues are limiting the hydrogen loading content to 3 % at 105 Pa, while former experiments are using pure hydrogen for the loading process at nearly same pressure e. g. [1]. Especially the thermal elongation coefficient (TDE operating conditions 300° to 500 °C compatibility to stainless steel) forces to think about an alternative material of boron silicate glass for specimen containment, in this paper copper will be discussed. The analysis of TDE concerns the amount of hydrogen stored in the specimen, stored in the time variable gas phase as well as stored in the containment material. These three phases are coupled by phase equilibrium. The here developed analysis procedure can currently only be performed numerically for a two dimensional geometry. However a two dimensional analytical solution regarding the same boundary condition is currently under investigation. One part of the solution results of this problem can be compared to an additional analytical solution with simpler boundary conditions, e.g. a vanishing hydrogen amount inside the specimen containment observed in steady state. The numerical results will be used to check the suitability of several experimental scenarios, for example the usability of a copper based specimen containment. The approach currently practiced in many experiments is to simply subtract the zero rate of hydrogen without considering the phase equilibrium between the three mentioned phases. The main goal of this analysis procedure consists in the solution of the inverse problem, namely the extraction of the transport parameters like Sieverts ́-and diffusion-constant from a measured time dependent desorption pressure increase.
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Bemui de V., M. Giselle, and Augusto Cárdenas R. "Cálculo de Dosis en Braquiterapia Ocular con Hilos de ir- 192 Utilizando la Integral de Sievert y Corregida por Atenuación y Dispersión con los Polinomios de Meisberg." Revista de Investigación de Física 8, no. 02 (December 30, 2005): 51–54. http://dx.doi.org/10.15381/rif.v8i02.8558.
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La braquiterapia ocular, muchas veces única alternativa para conservar el órgano visual en pacientes de cáncer ocular, se viene realizando en el Instituto Nacional de Enfermedades Neoplásicas utilizando hilos de Ir 192; los cuales, se colocan en forma radial sobre la superficie interior de un casquete esférico de oro de 18 K; el casquete permanece en el ojo hasta alcanzar la dosis prescrita por el médico. El objetivo principal de este trabajo es poder calcular de una manera correcta y práctica el tiempo que debe durar el tratamiento de braquiterapia ocular para alcanzar la dosis prescrita por el médico. Para alcanzar este objetivo se ha utilizado la integral de Sievert corregida por efectos de atenuación y dispersión (polinomios de Meisberg); calculándola por el método de Simpson. En los cálculos mediante la integral de Sievert no se toma en cuenta la dispersión producida por el casquete de oro ni la variación de la constante de frecuencia de exposición con la distancia. Los cálculos mediante integral de Sievert son comparados con los obtenidos utilizando el código de simulación Monte Cario Penélope, donde se observa que concuerdan a distancias de la superficie del casquete mayores o iguales a 2mm
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Zhang, Kai, Xuejia Lai, Jie Guan, and Bin Hu. "Selecting Rotation Constants on SIMON-Type Ciphers." Journal of Database Management 34, no. 1 (February 24, 2023): 1–23. http://dx.doi.org/10.4018/jdm.318452.
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In 2013, a lightweight block cipher SIMON is proposed by NSA. This paper tries to investigate this design criterion in terms of resisting against impossible differential cryptanalysis. On one hand, starting from all the possible rotation constants, this paper sieves those “bad parameters” step by step, for each step, the regular patterns for those “bad parameters” are deduced. Accordingly, basic rules for selecting rotation constants on SIMON-type ciphers to construct shorter longest impossible differentials are proposed. On the other hand, the authors categorize the optimal parameters proposed in CRYPTO 2015, according to these results, some “good parameters” in terms of differential cryptanalysis may be rather “bad parameters” while considering impossible differential cryptanalysis. Finally, a concrete attack on 26-round SIMON(13,0,10) is proposed, which is a suggested SIMON variant in CRYPTO 2015 against differential cryptanalysis and linear cryptanalysis. The result in this paper indicates that it is very important to choose appropriate rotation constants when designing a new block cipher.
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Krasin, V. P., S. I. Soyustova, and I. E. Lyublinskii. "Coordination cluster model for calculating Sievert’s constant of hydrogen solutions in melts of the Pb-Bi-Li system." Inorganic Materials: Applied Research 1, no. 4 (October 2010): 324–28. http://dx.doi.org/10.1134/s2075113310040106.
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Bolʼshov, L. A., S. K. Korneichuk, and E. L. Bolʼshova. "Wagner interaction coefficient between nitrogen and cobalt in liquid nickel-based alloy." Izvestiya. Ferrous Metallurgy 64, no. 5 (June 3, 2021): 363–65. http://dx.doi.org/10.17073/0368-0797-2021-5-363-365.
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The report describes a simple theory of thermodynamic properties of nitrogen solutions in liquid Ni– Co alloys. This theory is completely analogous to the theory for liquid nitrogen solutions in alloys of the Fe– Cr system proposed previously by the authors in 2019. The theory is based on lattice model of the Ni– Co solutions. The model assumes FCC lattice. In the sites of this lattice are the atoms of Ni and Co. Nitrogen atoms are located in octahedral interstices. The nitrogen atom interacts only with the metal atoms located in the lattice sites neighbouring to it. This interaction is pairwise. The initial values for the calculation are the Sieverts law constants for nitrogen solubility of in liquid nickel and in liquid cobalt. The result of the calculation is the value of the Wagner interaction coefficient in liquid nickel-based alloys at 1873 K = –1,35. This value is in good agreement with the experimental data (Kowanda and Speidel, 2003).
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Jiang, Tao, Yingzhi Bai, Lu Li, Weiwei Tai, Yujia Wang, Haiyan Wang, and Na Sun. "The effects of templates and seeds on the properties of nanosheet SAPO-34 molecular sieves and their catalytic performance in the MTO reaction." Australian Journal of Chemistry 76, no. 2 (February 28, 2023): 81–87. http://dx.doi.org/10.1071/ch22238.
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Nanoscale SAPO-34 molecular sieves were synthesized by adding different types of seed into hydrothermal synthesis systems with tetraethylammonium hydroxide (TEAOH) and triethylamine (TEA) & tetraethylammonium bromide (TEABr) as templates. The effects of different types of template and seed on the crystal structure, morphology, grain size and acidity of the molecular sieves were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 isothermal adsorption–desorption and ammonia temperature-programmed desorption (NH3-TPD). The methanol-to-olefins (MTO) reaction performance of the synthesized samples was investigated in a fixed-bed reactor. The results showed that crystalline supernatant and seed soaking solution could be used as liquid seeds to assist in the synthesis of SAPO-34 molecular sieves with a lamellar structure. The yield of SAPO-34 synthesized by seed increased from 38.64 to 59.68%, and the methanol conversion rate was significantly improved as compared with that of SAPO-34 synthesized without seed. The nano-thickness of SAPO-34 synthesized with TEA&TEABr instead of TEAOH as template decreased from 100–150 to 40–50 nm, and the lifetime increased from 360 to 400 min with the original yield kept constant.
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Hyun, S. H., and R. P. Danner. "Adsorption equilibrium constants and intraparticle diffusivities in molecular sieves by tracer-pulse chromatography." AIChE Journal 31, no. 7 (July 1985): 1077–85. http://dx.doi.org/10.1002/aic.690310705.
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Nakhl, Michel, Mirvat Zakhour, Charbel Amine, Houssam El-Rassy, and Samir F. Matar. "Effect of the Ball Milling Conditions, under Air, on the Preliminary Hydriding Properties of the Mixtures Mg-x Wt% Graphite. Role of Solvent." Advanced Materials Research 324 (August 2011): 119–24. http://dx.doi.org/10.4028/www.scientific.net/amr.324.119.
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The effect of wet milling on the hydriding properties of magnesium based mixture has been investigated. To prepare these mixtures, magnesium was ball milled with different weight percent of graphite (5, 10 and 25), at 300 rpm under air, for various duration using a ball miller apparatus Retsch S100 (R=12). Different solvents have been used such as benzene, heptane, styrene, DMSO. The hydriding properties were studied using a manual Sievert-type apparatus, at different temperatures (25°C, 100°C, 150°C and 200°C). The mixture Mg + 5wt% graphite milled during 6 hours in presence of 5mL heptane has shown the best hydriding properties at 150°C. The improvement of these properties has been related to the dielectric constant of the solvent and to the small size of the particles. The different mixtures have been analysed by means of scanning electron microscopy and laser granulometry.
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Kelly, A. "Why engineer porous materials?" Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1838 (November 29, 2005): 5–14. http://dx.doi.org/10.1098/rsta.2005.1686.
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A number of specific examples are briefly given for the use of pores in engineering materials: a porous ceramic to produce minimum thermal conduction; thin skeleton walls in silicon to produce photoluminescence; low dielectric constant materials. The desirable nature of the pores in fuel cell electrodes and sieves is described. Further examples are given in orthopaedics, prosthetic scaffolds and sound deadening and impact resistance materials. An attempt is made to describe the desirable pore size, whether open or closed, and the useful volume fraction. This short review does not deal with flexible foams.
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Bolʼshov, L. A., S. K. Korneichuk, and E. L. Bolʼshova. "Wagner coefficient of interaction between hydrogen and nickel in liquid steel." Izvestiya. Ferrous Metallurgy 65, no. 7 (July 27, 2022): 519–25. http://dx.doi.org/10.17073/0368-0797-2022-7-519-525.
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The simplest model of the structure and interatomic interaction is applied to hydrogen solutions in liquid alloys of Fe – Ni system, which earlier (2019 – 2021) was used by the authors for nitrogen solutions in alloys of Fe – Cr, Fe – Mn, Fe – Ni, Ni – Co and Ni – Cr systems. The theory is based on lattice model of the Fe – Ni solutions. The model assumes a FCC lattice. In the sites of this lattice are the atoms of Fe and Ni. Hydrogen atoms are located in octahedral interstices. The hydrogen atom interacts only with the metal atoms located in the lattice sites neighboring to it. This interaction is pairwise. It is assumed that the energy of this interaction depends neither on the alloy composition nor on the temperature. For simplicity it was assumed that liquid solutions in the Fe – Ni system are perfect. Within the framework of the proposed theory an expression is presented for the Wagner coefficient of interaction between hydrogen and nickel in liquid steel. The right-hand part of the appropriate formula is a function of the ratio of the Sieverts law constants for hydrogen solubility in liquid iron and in liquid nickel. The values of these constants for a temperature of 1873 K are taken equal to K′H(Fe) = 0,0025, K′H(Ni) = 0,0040 wt. %. At the same time, an estimate was obtained for the Wagner coefficient of interaction between hydrogen and nickel in liquid steel εHNi = –0,54. This corresponds to the value of the Langenberg interaction coefficient eHNi = –0,002, wich is very close to the experimental estimate eHNi = –0,0022.
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Hofmański, Wojciech. "Adaptacja i porozumienie. Komunikacja dwujęzyczna w Europie Środkowej." Slavia Occidentalis, no. 75/1 (December 15, 2019): 29–40. http://dx.doi.org/10.14746/so.2018.75.3.
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Depending on the selected theoretical concept, Central Europe is a melting pot of several or over a dozen linguistic cultures which constantly interacted in the process of historical development. In this multi-national landscape, the presence of Slavs (Czechs, Poles, Slovaks as well as Lusatians, Kashubians or Lemkos) has been a constant element. The speakers have used two languages in a single act of communication which is a phenomenon of its own. This understanding is a tempting area of linguistic research. This text is dedicated to bilingual communication of Slavs with special emphasis placed on the processes of adaptation based on obtaining information from texts in written language (the seven sieves technique).
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García Nofuentes, Juan, and Roser Martínez Ramos e Iruela. "Essence-Temporality Paradigm." Estoa, no. 15 (2019): 79–93. http://dx.doi.org/10.18537/est.v008.n015.a07.
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The «tobacco curing houses» scattered across the landscape of the Vega of Granada, mean something more than the memory of a marginal, beautiful and forgotten architecture. These simple models of industrial architecture that pursue the «essence», turn into light and sensations sieves, that can be pierced by senses owing to a drilled and protagonist epidermis, with great expectations of giving shelter to the most unlike uses. From the inquiry into the infallibility of the architectural fact, coming from the observation of «permanent qualities», foreign to styles, uses, economy, social conditions or culture, which make architecture an eternal demand, the «invariants» that are being discovered from the inductive analysis of models of the embryonic architecture of this peculiar inherited heritage, are revealed, in a constant intertextual exercise.
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Jänchen, Jochen, Vladimir Penchev, Elke Löffler, Barbara Parlitz, and Helmut Stach. "Influence of Silicon Content and Nature of the Template Molecule on Physico-Chemical and Catalytic Properties of SAPO-5." Collection of Czechoslovak Chemical Communications 57, no. 4 (1992): 826–35. http://dx.doi.org/10.1135/cccc19920826.
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Two series of SAPO-5 molecular sieves were synthesized: (i) Using tripropylamine as a template and varying the Si content in the gel, and (ii) varying the template molecule at constant silicon content in the gel. The products were characterized physico-chemically and tested in toluene disproportionation. It was found that the rising silica content in the synthesis gel has only little influence on the SiO2 incorporation into the SAPO. Investigation of the acid character revealed that the concentrations of the adsorbed ammonia molecules are nearly constant and independent of the total silicon content of the crystals. The catalytic activity showed no correlation either with the silicon content of the catalysts or with the acidity measured by temperature-programmed desorption of ammonia. It is concluded that the incorporated silicon exists not only in a monomeric form and that the TPD of ammonia reflects not only the strong Bronsted acidity. The SAPO-5 sample synthesized with triethylamine possessed the strongest acidity corresponding to the highest catalytic activity. It is supposed that in the presence of TEA molecules silicon replaces mainly P atoms in the AlPO4-5 framework.
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Saharty, Abeer Al. "Phytoremediation of Heavy Metals from Wastewater Using Bean Plants." Biosciences Biotechnology Research Asia 11, no. 3 (December 30, 2014): 1373–80. http://dx.doi.org/10.13005/bbra/1529.
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The Bean Plants were used in this work as low cost adsorbent material for removal of Pb(II), Cd(II) and Zn(II) ions from aqueous solutions. The samples were prepared and sorted according to the particles diameter by standard sieves 250 - 500 µm. Batch adsorption experiments were carried out to study the adsorption process pH of adsorbent, effect of contact time, effect of adsorbent amount and effect of metal concentration were Investigated in these experiments. The effect of any one of those previously mentioned parameters on the adsorption capacity were studied while the other parameters were kept constant. The maximum adsorption capacities of beans for the removal of selected heavy metals were very high. It is suggested to use it as a low coast adsorbent material to clean up the water in the environment from toxic heavy metals.
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Wu, Xinyu, Zhongyang Bai, Lin Wang, Guangchao Cui, Mengzheng Yang, Qing Yang, Bo Ma, et al. "Magnetic Cell Centrifuge Platform Performance Study with Different Microsieve Pore Geometries." Sensors 20, no. 1 (December 20, 2019): 48. http://dx.doi.org/10.3390/s20010048.
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The detection and analysis of circulating tumor cells (CTCs) plays a crucial role in clinical practice. However, the heterogeneity and rarity of CTCs make their capture and separation from peripheral blood very difficult while maintaining their structural integrity and viability. We previously demonstrated the effectiveness of the Magnetic Cell Centrifuge Platform (MCCP), which combined the magnetic-labeling cell separation mechanism with the size-based method. In this paper, a comparison of the effectiveness of different microsieve pore geometries toward MCCP is demonstrated to improve the yield of the target cell capture. Firstly, models of a trapped cell with rectangular and circular pore geometries are presented to compare the contact force using finite element numerical simulations. The device performance is then evaluated with both constant pressure and constant flow rate experimental conditions. In addition, the efficient isolation of magnetically labeled Hela cells with red fluorescent proteins (target cells) from Hela cells with green fluorescent protein (background cells) is validated. The experimental results show that the circular sieves yield 97% purity of the target cells from the sample with a throughput of up to 2 μL/s and 66-fold sample enrichment. This finding will pave the way for the design of a higher efficient MCCP systems.
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Tiehm, A., V. Herwig, and U. Neis. "Particle size analysis for improved sedimentation and filtration in waste water treatment." Water Science and Technology 39, no. 8 (April 1, 1999): 99–106. http://dx.doi.org/10.2166/wst.1999.0395.
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Size distributions of particle mass, chemical oxygen demand (COD) and phosphorus at four municipal waste water treatment plants were investigated by fractionation of samples through 0.1-8.0 μm polycarbonate filters and 32-125 μm sieves, respectively. Particle size analysis of primary and secondary effluents at each plant showed significantly different size distribution functions. These distribution functions remained constant with respect to time under dry weather conditions so they can be considered as characteristic patterns for each sample location. Advanced treatment by deep bed filtration can be improved by taking into consideration the distribution pattern in the secondary effluents. In raw sewage and primary effluents 45-90% of COD and 35-80% of phosphorus were associated with suspended solids. In the secondary effluents particulate COD drops to 14-45% but particulate phosphorus increases to 55-80%. Conclusions are drawn for a better design of advanced contaminant reduction in connection with suspended solids removal processes.
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Vargas-Bustamante, Jaquebet, Pedro Martínez-Ortiz, Daniel Alvarado-Alvarado, Ulises Torres-Herrera, and Jorge Balmaseda. "Experimental Setup and Graphical User Interface for Zero-Length Column Chromatography." Applied Sciences 12, no. 13 (July 1, 2022): 6694. http://dx.doi.org/10.3390/app12136694.
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This work describes the design and implementation of a Zero-Length Column system to measure: diffusion coefficients, adsorption isotherm parameters of pure components and mixtures. In addition, a graphical user interface (GUI) was developed in LabVIEW for the semi-automatic operation of the system. The system is novel because it integrates all the aforementioned functionalities without using mass spectrometry. Two adsorbents, zeolite 5A and Basolite® C300 (Copper benzene-1,3,5-tricarboxylate) and two adsorbates methane and ethane were used to perform the validation of adsorption and diffusion experiments. The Henry constants and diffusion coefficients obtained reproduce those previously reported. The combination of the experimental setup and the GUI significantly reduce the amount of sample and measurement time needed in the characterization of the molecular sieves by conventional volumetric and gravimetric systems. The proposed system is relatively inexpensive, robust, easy to build, and capable of reproducing the results of other techniques.
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Djoković, Jelena M., Ružica R. Nikolić, and Jan Bujnak. "Prediction of the Fatigue Life of the Vibrational Sieve Supporting Beam." Key Engineering Materials 755 (September 2017): 274–78. http://dx.doi.org/10.4028/www.scientific.net/kem.755.274.
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Vibrational sieves are exposed to exceptionally high cyclic loading during their working life and that is the reason why the special attention should be paid to estimates of the fatigue life of their structural elements, as well as to design with respect to fatigue fracture. Any change in the design appearance of the structural component must be carefully analyzed, since even the rearrangement of the components' elements layout, with keeping all the sizes constant, can cause serious consequences to the particular component's fatigue life. The research subject considered in this paper is the remaining fatigue life of the carrying beam, as well as the suggestions for improving the working life of the vibrational sieve. The Paris' law was used for estimates of the average crack propagation rate. From the presented diagram of the initial crack length versus the remaining working life one could see that the fatigue life decreases with the crack length increase. When the initial crack length reaches a value a little less than a half of the critical crack length, the remaining fatigue life starts to drop abruptly.
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Shah, Pooja, Amish Sharma, Jayanti Gyawali, Sharma Paudel, Shanta Lall Shrestha, and Surendra Maharjan. "Dose optimization in computed tomography of brain using CARE kV and CARE Dose 4D." Radiography Open 4, no. 1 (December 30, 2018): 9. http://dx.doi.org/10.7577/radopen.3110.
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Background: Computed Tomography (CT) scan of brain is the most widely used CT examination. Latest CT scanners have the potential to deliver very low radiation dose by utilizing tube potential and tube current modulation techniques. We aim to determine the application of CARE kV (tube potential modulation) and CARE Dose4D (tube current modulation) in CT scan of brain. Both CARE kV and CARE Dose4D are well-established innovative technology of Siemens Medical Solutions.
Methodology: A prospective hospital-based study was conducted during four months at Tribhuvan University Teaching Hospital (TUTH). The data were collected on a Siemens Somatom Definition Edge 128 slices CT scanner. Non-random purposive sampling technique was employed. Ethical approval and consent to participate were taken for every participant. Non-contrast (NC) CT images were acquired without using CARE kV and CARE Dose4D, whereas during contrast-enhanced (CE) investigation, both were turned on keeping other scanning parameters constant for each individual.
Results: A total of 72 patients, 42 males and 28 females - mean age 41y (range 16-87y) participated in this study. The Body Mass Index (BMI) was 22.0, range 20.1-25.0. The mean value of Computed Tomography Dose Index (CTDI), Dose Length Product (DLP) and Effective Dose (ED) before and after switching on both CARE kV and CARE Dose4D were 58.19±0.35 and 39.67±3.59 milli-Gray (mGy), 946.67 and 652.58 mGy-cm, and 1.98 and 1.36 milli-Sievert (mSv) respectively.
Conclusion: CARE kV and CARE Dose4D can reduce radiation dose in CT scan of brain without loss of image quality.
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Megawati, Dewi Selvia Fardhyanti, Radenrara Dewi Artanti Putri, Oki Fianti, Agustin Fitrianingsi Simalango, and Afiati Estrina Akhir. "Synthesis of Silica Powder from Sugar Cane Bagasse Ash and Its Application as Adsorbent in Adsorptive-distillation of Ethanol-water Solution." MATEC Web of Conferences 237 (2018): 02002. http://dx.doi.org/10.1051/matecconf/201823702002.
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In this study, sugarcane bagasse ash (SCBA) as waste from sugarcane factory was extracted into silica powder. This powder was then used as adsorbent for ethanol purification. Prior to used, the SCBA was washed using HCl solution. The silica extraction was conducted using various NaOH concentrations (0.5; 1; 1.5 and 2 mol/L) as well as extraction times (30, 60 and 90 minutes). After that the mixture was precipitated using HCl solution. The solution was filtrated through a paper filter and its solid particle was dried until its weight was constant. The particle was grounded and sieved using 18 mesh sieves. The silica powder obtained was analysed using FTIR and its result showed that the powder has silica functional groups. The silica yield increases with increasing of concentration of NaOH solution as well as extraction time. The highest silica yield (45.5% w/w) was achieved at 2 mol/L NaOH solution at 90 min. The surface area, pore diameter, and pore volume of silica powder were measured to be 407 m2/g, 3.81Å, and 2.76 dm3/g, respectively. From application of silica powder as adsorbent in adsorptive-distillation, ethanol concentration can reach 99.3% w/w which indicates azeotropic point can be passed.
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Kim, Han-eol, Kyoung-min Nam, Hafeezur Rehman, Tae-su Kyeon, and Han-kyu Yoo. "Comparison Study on Coarseness Index and Maximum Diameter of Rock Fragments by Linear Cutting Tests." Applied Sciences 12, no. 17 (September 1, 2022): 8793. http://dx.doi.org/10.3390/app12178793.
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Rock fragments obtained by excavation can provide information for evaluating the excavation efficiency, for which the coarseness index (CI) and particle size parameters (d50, dMPS, and d′) are used. However, CI depends on the number and size of the sieves used, and the particle size parameters require mathematical calculations. In this study, the maximum diameter (dmax) of rock fragments was used as an indicator of the excavation efficiency. Linear cutting tests were performed and the rock fragments were sieved to obtain the CI and dmax. The relationship between dmax and CI was similar to that between other particle parameters and CI. dmax and CI increased with increasing penetration depth and spacing, but dmax followed a linear relationship, and CI demonstrated a power relationship. Both dmax and CI reached their maximum values at a specific ratio of spacing to penetration depth (s/p ratio) and were not affected by subsequent increases in s/p. The cutting force and volume had positive relationships with dmax and CI, linear with dmax and exponential with CI, whereas the specific energy (SE) had an inverse relationship, showing exponential and linear relationships with dmax and CI, respectively. When dmax was larger than a certain value, SE converged to a constant value. This study confirmed that dmax has an advantage over CI in determining excavation efficiency.
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Pan, Z. J., S. G. Chen, J. Tang, and R. T. Yang. "Pore Structure Alteration of a Carbon Molecular Sieve for the Separation of Hydrogen Sulfide from Methane by Adsorption." Adsorption Science & Technology 10, no. 1-4 (March 1993): 193–201. http://dx.doi.org/10.1177/0263617499010001-418.
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The equilibrium adsorption of H2S is substantially stronger than that of CH4 on carbons, including carbon molecular sieve (CMS). A carbon molecular sieve with a proper pore structure can provide a kinetic selectivity for H2S over CH4, thus further enhancing the overall selectivity (equilibrium plus kinetic) for H2S and providing the basis of natural gas desulfurization by adsorption. Kinetic selectivity requires a unique pore structure due to the small difference in the molecular dimensions of H2S and CH4 (~0.2 Å). Equilibrium and diffusion rate data for CH4 and H2S at 25°C have been measured in three commercial carbon molecular sieves: Bergbau Forschung CMS, Takeda CMS 3A and Takeda CMS 5A. The pores are either too small (in the two former carbons) or too large (in CMS 5A) for H2S/CH4 separation. Alterations to the pore structure either by controlled oxidation or carbon deposition by pyrolysis have been studied. Optimal results were obtained by pyrolysis of propylene on CMS 5A under the following conditions: 0.05 atm, 700°C, 5 min, weight gain of 0.67%. The resulting carbon molecular sieve retained the high equilibrium adsorption capacities while yielding a diffusion time constant ratio for H2S/CH4 of 8.2. This carbon is suitable for natural gas desulfurization by adsorption processes such as pressure swing adsorption. Temperature was the most important variable in pore structure alteration by carbon deposition. Under the optimal pyrolysis conditions, carbon was only deposited near the pore entrances.
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Rumbo Morales, Jesse Y., Alan F. Perez Vidal, Gerardo Ortiz Torres, Alexis U. Salas Villalobo, Felipe de J. Sorcia Vázquez, Jorge A. Brizuela Mendoza, Miguel De-la-Torre, and Jorge S. Valdez Martínez. "Adsorption and Separation of the H2O/H2SO4 and H2O/C2H5OH Mixtures: A Simulated and Experimental Study." Processes 8, no. 3 (March 4, 2020): 290. http://dx.doi.org/10.3390/pr8030290.
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Adsorption processes are characterized by their kinetics and equilibrium isotherms described by mathematical models. Nowadays, adsorption with molecular sieves is a method used to separate certain elements or molecules from a mixture and produce hydrogen, nitrogen, oxygen, ethanol, or water treatment. This study had two main objectives. The first one was focused on the use of different natural (Clinoptilolite-S.L. Potosi, Clinoptilolite-Puebla, and Heulandite-Sonora) and synthetic (Zeolite Type 3A) adsorbents to separate the mixtures H 2 O / H 2 S O 4 and H 2 O / C 2 H 5 O H . It was determined that both Zeolite Type-3A and Heulandite-Sonora have greater adsorption capacity in a shorter time compared with the Clinoptilolites at different temperatures. The second objective was the simulation of a pressure swing adsorption process to dehydrate ethanol using the parameters obtained from Zeolite Type 3A (with maximum adsorption capacity). Several configurations were considered to calculate the appropriate nominal values for the optimal process. The results illustrate that the purity of ethanol is increased when the following parameters are considered in the adsorption process: a high pressure, a constant temperature between 100 and 120 ° C, a feed composition near the azeotropic point with lower water content, and a purge pressure near the vacuum. Finally, the results show that it is possible to take advantage of the length of the absorber bed in order to reduce the energy costs by increasing the ethanol production as well as complying with the international purity standards.
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Bubnov, E. A., and D. V. Don. "Optimization of tobacco seed cleaning modes." New Technologies 16, no. 5 (December 31, 2020): 13–19. http://dx.doi.org/10.47370/2072-0920-2020-16-5-13-19.
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The process of obtaining high-quality tobacco seeds is very laborious, and at present many operations are performed manually at All-Russian Research Institute of Tobacco, Makhorka and Tobacco Products. The process of obtaining tobacco seeds at the Institute consists of the following operations: harvesting of inflorescences, drying of inflorescences, destruction of inflorescences, screening out coarse impurities, final cleaning in an air stream. An attempt was made earlier to mechanize and improve working conditions at the stage of final purification of the seed mixture. A unit for the final purification of tobacco seeds was developed, manufactured and tested. In this article other modes of final purification of the tobacco seed mixture to improve mechanization and productivity of the same unit have been tested. The seed mix of the 2019 harvest has been used in the studies. Coarse impurities have been separated from the seed mix by sieving through sieves with different hole sizes. Earlier modes of double final purification of seed mixture were proposed. In this research the previously proposed double cleaning modes have been taken as control ones, and in the experiment three-fold modes with a higher feed rate of the seed mixture have been used. As a result, the experimental modes provide identical removal of contaminants, however, the productivity of the unit increases 2 – 3 times due to the shorter total duration of purification, and mechanization is also improved due to a more uniform flow of the seed mixture. In this case, there is no need for the constant presence of an operator, and the process of final purification of the tobacco seed mixture is reduced only to its loading and unloading.
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Pha, Tran Thi, Tran Hai Dang, Ban Thi My, Oleg B. Rudakov, and Elena A. Khorokhordina. "Application of crushed shells Cristaria plicata to separation cadmium and chromium from polluted water by static sorption." Сорбционные и хроматографические процессы 20, no. 5 (November 25, 2020): 556–64. http://dx.doi.org/10.17308/sorpchrom.2020.20/3047.
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Cristaria plicata is a species of freshwater mollusk in the genus Cristaria of the family Unionidae. Cristaria plicata shells are available natural raw materials in Vietnam for the production of sorbents that can absorb many pollutants from wastewater. The most important pollutants are heavy metals. The aim of the study was to study the possibility of using powders from Cristaria plicata shells to purify contaminated water from heavy metals such as Cd and Cr by sorption method. A technology for obtaining a sorbent has been developed. After collection, the shells were washed, dried and ground to a size of no more than 0.5 mm, then the powder was soaked in distilled water for 10 hours, dried to a constant weight and sieved through sieves, collecting a fraction with a particle size of about 0.5 mm. Microscopic studies showed that the sorbent parti-cles from the shells of Cristaria plicata contained pores with a diameter of 4.5 to 8.2 microns and a length of 15.9 to 27.6 microns. The static sorption method was used. The Cd and Cr content in water samples before and after sorption was performed by atomic absorption spectrophotometry. It is shown that the sorbent from the shell material of Cristaria plicata can be used quite effectively for wastewater treatment from Cd and Cr. It was found that with an increase in the mass fraction of the powder in the treated water, the concentration of Cr and Cd in this water noticeably decreases. The Cr content drops by 29.5-45.5% after shaking for 60 minutes, while the Cd content drops by 91.6-96.9%. The absorption capacity of the sorbent from the shells of Cristaria plicata depends on the initial concentrations of Cr and Cd, the higher the initial concentration, the more pollutants are absorbed by the sorbent. The best effect of sorption purification is observed at the initial concentrations of Cd 1 mg/l and Cr 20 mg/l. For maximum Cd allocation, the recommended processing time is 40÷60 minutes, and for Cr-80÷100 minutes.
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Schwartz, Daniel S., Scott Richmond, Alice I. Smith, Alison Costello, and Christopher D. Taylor. "Hydrogen-Vacancy Effects in Pu-2 at. % Ga Alloys." MRS Proceedings 1444 (2012). http://dx.doi.org/10.1557/opl.2012.1125.
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ABSTRACTPlutonium and Pu-Ga alloys have been observed to have anomalous hydrogen solubility behavior, including a significant concentration dependence of hydrogen diffusivity in the dilute regime, a sharp drop off in the hydrogen solubility constant in the dilute regime, and a near complete absence of change in the Sieverts’ constant as the alloys are heated across phase transformation boundaries. We are investigating the possibility that a vacancy mechanism is responsible for this behavior. X-ray diffraction measurements show a 0.14% lattice contraction in Pu-2 at. % Ga alloys when they are charged with ~2 at. % hydrogen. The lattice re-expands when the hydrogen is removed. Density functional calculations show that increasing the number of hydrogen atoms associated with a vacant lattice site in Pu lowers the energy of the hydrogen-vacancy complex. These observations support the idea that vacancies are stabilized by hydrogen in the Pu lattice well beyond their thermal equilibrium concentration and could be responsible for the anomalous hydrogen response of Pu.
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Ishikawa, Kazuhiro, Shintaro Noda, Kiyonori Suzuki, and Kiyoshi Aoki. "Hydrogen absorption of C14 Laves NiTiZr-NiVNb pseudo-binary alloys." MRS Proceedings 801 (2003). http://dx.doi.org/10.1557/proc-801-bb3.2.
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ABSTRACTHydrogen absorption and desorption properties of C14 Laves NiTiZr-NiVNb and NiTiZr-NiVZr pseudo-binary alloys were investigated by using the Sieverts' apparatus, XRD and the hydrogen analyzer. The hydrogen capacity and the 50% hydrogen desorption temperature, Td, of the C14 Laves NiTiZr alloy is 1.5 (H/M) and 850 K, respectively. On the other hand, the hydrogen capacity of the C14 NiVNb alloy is 0.2 H/M. In the Ni(TiZr)1−x(VNb)x pseudo-binary system, the hydrogen capacity of the alloys is decreased with increasing x, but the 50% hydrogen desorption temperature is almost constant. The substitution of VNb reduces the hydrogen absorption capacity of the C14 Laves NiTiZr alloy. The hydrogen desorption temperature of Ni(Ti1−xVx)Zr alloy is reduced to 580 K without serious decrease of the hydrogen capacity with increasing x.
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Jing, Wenna, Jianxing Liu, Hengxin Guo, Sishu Wang, Hailin Bi, Bo Chen, Jianjun Chen, et al. "Gas- and plasma-driven hydrogen permeation behavior of stagnant eutectic-solid GaInSn/Fe double-layer structure." Chinese Physics B, September 21, 2022. http://dx.doi.org/10.1088/1674-1056/ac9365.
Full textAbstract:
Abstract Gas- and plasma-driven hydrogen permeation through GaInSn/Fe have been systematically investigated in this work. The permeation parameters of hydrogen through GaInSn/Fe, including diffusivity, Sieverts’ constant, permeability and surface recombination coefficient were obtained. The permeation flux of hydrogen through GaInSn/Fe shows a great dependence on external conditions such as temperature, hydrogen pressure, and thickness of liquid GaInSn. What’s more, the hydrogen permeation behavior through GaInSn/Fe is in good agreement with the multilayer permeation theory. In PDP and GDP experiments, hydrogen through GaInSn/Fe satisfies the diffusion-limited regime. In addition, the permeation flux of PDP is greater than that of GDP. The increase of hydrogen plasma density hardly causes the change of hydrogen PDP flux within the test scope of this work, which is due to the dissolution saturation. These findings provide guidance for a comprehensive and systematic understanding of hydrogen isotope recycling, permeation, and retention in plasma-facing components under actual conditions.
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"The influence of surface tension on the diffusion-controlled growth or dissolution of spherical gas bubbles." Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences 420, no. 1859 (December 8, 1988): 247–65. http://dx.doi.org/10.1098/rspa.1988.0126.
Full textAbstract:
Surface tension can markedly affect the growth or dissolution of small gas bubbles but, even when spherical symmetry is maintained and the interfacial concentration assumed constant, generally valid analytical solutions for the change of size with time cannot be obtained; approximations of limited validity are therefore often used. However, accurate and efficient methods for computing the diffusion-controlled growth or dissolution of spheres in such conditions have recently been developed; the results obtained when interfacial solute concentration is assumed constant have been published and validated by comparing them, where possible, with the equivalent analytical solutions. This paper extends that work to include the effects of a constant surface tension, for both Henry’s and Sievert’s laws. The numerical results are valid for as wide a range of parameters as is likely to be needed and are compared with the few analytical solutions available for particular cases. It is shown that, when surface tension is introduced, a complete description of the problem requires an additional saturation parameter as well as the dimensionless surface tension. It is also shown that Henry’s and Sievert’s laws can have very different effects on dissolving bubbles: when Sievert’s law applies a higher surface tension can increase time for a bubble to dissolve but this paradox can be resolved by examining the competing effects involved.
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Speakman, Scott A., Joachim H. Schneibel, and Dewey S. Easton. "An in-situ X-ray Diffraction Study of the Desorption of TiCl3-doped Sodium Alanate." MRS Proceedings 837 (2004). http://dx.doi.org/10.1557/proc-837-n3.3.
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ABSTRACTSodium alanate was milled with and without TiCl3. The hydrogen release and uptake was measured during temperature-programmed absorption and desorption, as well as by isothermal charging and discharging, using a Sieverts' type apparatus. These data were supplemented by in-situ X-ray diffraction studies of hydrogen desorption. Rate constants derived from XRD were slower than those derived from volumetric H2 measurements. Al formation observed in XRD exceeded that expected from the observed decomposition of NaAlH4 and Na3AlH6.
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Noel Buckley, D., and M. M. Matthiesen. "The Influence of the Arsine Source on the Purity of InGaAs Grown by Hydride VPE." MRS Proceedings 144 (1988). http://dx.doi.org/10.1557/proc-144-335.
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ABSTRACTThe relatively high background carrier concentration obtained in unintentionally doped epitaxial layers of III-V materials imposes a limitation on applications of the hydride VPE process. It is usually attributed to impurities in the gas sources. Results are presented for InGaAs grown by hydride VPE using a range of growth conditions. Carrier concentrations and growth rates for the various samples were determined using, respectively, Polaron electrochemical profiler measurements and scanning electron microscopy. It is shown that the observed background carrier concentration increased with increasing input mole fraction of arsine under conditions of constant growth rate. This strongly implicates the arsine feed gas as a predominant source of impurity. Attempts to purify the arsine feed gas using sodium alumina-silicate molecular sieves are described. Polaron electrochemical profiler measurements and Hall effect measurements on samples grown both with and without molecular sieves in the arsine feed line are presented. From a comparison of the corresponding values of carrier concentration and mobility it is shown that Type 4A molecular sieves were not effective in removing dopant impurities from the 4% arsine-hydrogen mixture used.
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Cheu, Darrell, Thomas Adams, and Shripad T. Revankar. "Hydrogen Loading System for Thin Films for Betavoltaics." Journal of Nuclear Engineering and Radiation Science, February 27, 2023, 1–9. http://dx.doi.org/10.1115/1.4056974.
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Abstract Betavoltaics are direct conversion energy devices that are ideal for low power and long-lasting, uninterruptable applications. Betavoltaics operate similarly to photovoltaics where a radioisotope irradiates beta particles into a semiconductor p-n junction that converts the kinetic energy into electrical energy. Betavoltaics are limited by their power output from the radioisotope. However, the source power density can be increased by the selection of solid-state substrates. While tritium absorbing substrates can be simulated to estimate tritium absorption levels and surface emission energies, their viability has to be physically evaluated. A state-of-the-art hydrogen loading system developed by our research group was used to evaluate different film types to understand how they perform during the hydrogen/tritium loading process. The hydrogen loading system utilizes the Sievert technique, where the temperature and volume is constant and pressure drop of the system is used to determine hydrogen uptake of a film substrate. The hydrogen loading system procedure was verified using 250 nm thick palladium films at three loading temperatures. Results clearly show uptake of hydrogen by the thin palladium films accurate to the ideal stoichiometric ratio of one hydrogen atom to host palladium atom.
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Pham Van, Chinh, Tuan Le Quang, Hieu Nguyen Tuan, and Tien Vu Dinh. "Study on calculating kinetic parameters of mathematical model describing the adsorption process of a single fixed bed of N2 gas generator working by pressure swing adsorption (PSA) and using carbon molecular sieves CMS-240." Vietnam Journal of Catalysis and Adsorption 9, no. 1 (March 10, 2021). http://dx.doi.org/10.51316/jca.2020.13.
Full textAbstract:
Nitrogen generator working by pressure swing adsorption cycle using carbon molecular sieves adsorbent is widely used in industry at small and medium scale in recent years, due to its convenience. This is equipment that uses a molecular size selective adsorption technique to separate nitrogen from air. In general, kinetic modeling and optimization are commonly used to analyze the process dynamics of the adsorption column at various operating conditions in which process parameters such as gas concentration, operating temperature and pressure are considered to be functions of time and bed height. In this paper, a mathematical model describing the adsorption column according to the pressure function is established following time and the height of the bed assuming that the velocity through area of the bed is constant at each pressure. The results of these calculations are model parameters that describe the adsorption process of the column. This model can be solved by MATLAB software to simulate the adsorption process of the column. This study was carried out on a nitrogen gas generator that was researched and designed at the Institute of Technology - General Department of Defense Industry to simulate, optimize and scale-up.
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Pham Van, Chinh, Tuan Le Quang, Hieu Nguyen Tuan, and Tien Vu Dinh. "Study on calculating kinetic parameters of mathematical model describing the adsorption process of a single fixed bed of N2 gas generator working by pressure swing adsorption (PSA) and using carbon molecular sieves CMS-240." Vietnam Journal of Catalysis and Adsorption 9, no. 1 (April 30, 2020). http://dx.doi.org/10.51316/jca.2020.001.
Full textAbstract:
Nitrogen generator working by pressure swing adsorption cycle using carbon molecular sieves adsorbent is widely used in industry at small and medium scale in recent years, due to its convenience. This is equipment that uses a molecular size selective adsorption technique to separate nitrogen from air. In general, kinetic modeling and optimization are commonly used to analyze the process dynamics of the adsorption column at various operating conditions in which process parameters such as gas concentration, operating temperature and pressure are considered to be functions of time and bed height. In this paper, a mathematical model describing the adsorption column according to the pressure function is established following time and the height of the bed assuming that the velocity through area of the bed is constant at each pressure. The results of these calculations are model parameters that describe the adsorption process of the column. This model can be solved by MATLAB software to simulate the adsorption process of the column. This study was carried out on a nitrogen gas generator that was researched and designed at the Institute of Technology - General Department of Defense Industry to simulate, optimize and scale-up.
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Favare, Henrique Guimarães De, Joadil Gonçalves De Abreu, Livia Vieira De Barros, Felipe Gomes Da Silva, Luis Miguel Mendes Ferreira, Marco Antônio Aparecido Barelli, Inácio Martins da Silva Neto, et al. "Bromatological Composition of Elephant Grass Genotypes for Bioenergy Production." Journal of Experimental Agriculture International, June 28, 2019, 1–12. http://dx.doi.org/10.9734/jeai/2019/v38i230292.
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Aimed to evaluate the bromatological composition of different genotypes of elephant grass (Pennisetum purpureum Schum.) to energy production through combustion. The experimental design was a randomized block with 3 repetition and the treatments arranged in a subdivided plots scheme, considering as a plots the thirteen genotypes and harvests (dry and rainy) as subplots. The genotypes evaluated were Cubano Pinda, Porto Rico, Vrukwona, Piracicaba 241, Cuba 116, Taiwan A-25, Mecker, Napier, Canará, Guaçu, Cameroon, CNPGL 93-41-1 and CNPGL 91-25-1 clones. The experiment lasted two consecutive years with harvests made every 6 months, with a harvest in the dry season (September) and another one in the rainy season (March), totaling 4 harvests. For dry matter content analysis, three tillers were selected at random and dried in an oven at 55ºC until reaching a constant mass. For biomass quality analysis, the samples were ground in Willey type mills with 1 mm sieves, submitted to bromatological analysis to determine the neutral detergent fiber, acid detergent fiber, hemicellulose, volatile materials, and fixed carbon content. Higher levels of dry matter (greater than 44.4%), acid detergent fiber (greater than 44.8%), volatile matter (greater than 94.3%) and higher calorific value (greater than 3,450 kcal kg-1) occur in the dry period of the year and in genotypes Mercker, Piracicaba 241, Guaçu and BRS Canará genotypes.
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Cardoso, Rodrigo Torres, Alexandre Kannebley de Oliveira, and Julio Cesar Garavello. "Longitudinal distribution of the ichthyofauna in a tributary of Tietê River with sources on the Basaltic Cuestas of São Paulo, Southeastern Brazil." Biota Neotropica 16, no. 2 (June 2016). http://dx.doi.org/10.1590/1676-0611-bn-2015-0005.
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This work aimed to study the composition and distribution of fish species at four sites along Cabeça River, an affluent of Corumbataí River, tributary of Tietê River, intending to better understand the influence of local geomorphology on the occurrence of the species along the river. Using gill nets, trawl net, cast net and sieves, five samples were taken from each site every two months. These data were analyzed from constancy of occurrence, similarity index of Jaccard, rarefaction analysis and descriptive statistical analysis of richness. 4,532 fish individuals belonging to six different orders, 17 families and 65 species were captured. Differences in composition, richness (diversity), abundance and frequency were observed at these sites along the river. The sample site near the mouth of Cabeça River, was richer (49 species) and more abundant than the other three upstream sites, which showed fewer species and equivalent amounts each other (between 22 and 29 species). Moreover, this downstream site had the highest percentage of accessory species, whereas the other samples had a greater number of constant species. Cluster analysis from the Jaccard similarity showed that each site had distinct species composition. Cabeça River basin drains a rugged terrain in the state of São Paulo, between the Basaltic Cuestas and Peripheral Depression geomorphologic provinces. In this scenario, waterfalls and rapids influence the distribution, composition and richness of fish species.
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Pasquini, Luca, Elsa Callini, Emanuela Piscopiello, Amelia Montone, Torben René Jensen, Marco Vittori Antisari, and Ennio Bonetti. "Hydrogen Sorption in Magnesium Nanoparticles: Size- and Surface-related Phenomena." MRS Proceedings 1216 (2009). http://dx.doi.org/10.1557/proc-1216-w05-04.
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AbstractThe aim of this work is the investigation of the metal-hydride transformation in magnesium (Mg) nanoparticles both as a function of particle size and in response to surface functionalization by clusters of transition metals (TM): Pd, Ni, Ti.Mg nanoparticles were synthesized by the inert-gas condensation technique, which yields single crystals with six-fold symmetry whose average size can be controlled by tuning the inert gas pressure. After the synthesis the nanoparticles were passivated by slow exposure to oxygen, obtaining a core-shell morphology where a metallic core is coated by a MgO shell of about 5 nm thickness.The material structure was investigated by Transmission Electron Microscopy (TEM), also in High Resolution (HRTEM) mode, and by X-Ray Diffraction (XRD). The sorption kinetics were analysed by a volumetric Sievert apparatus, which also allowed for a determination of the activation energies.Small nanoparticles (≈35 nm) display interesting kinetics with gravimetric capacity of 4.5 wt.% at saturation, limited by the oxide fraction. Hydride formation proceeds by one-dimensional growth controlled by diffusion through the hydride, while the reverse transformation to metal involves interface-controlled three-dimensional growth of nuclei formed at constant rate.On the contrary, large nanoparticles (≈450 nm) exhibit very low reactivity due to reduced probability of hydrogen dissociation/recombination and nucleation at the particle surface. For this reason, large nanoparticles were surface-decorated by TM through in situ evaporation in the inert-gas condensation chamber. This procedure results in clusters of 3-4 nm located over a portion of the MgO shell, as shown by XRD and HRTEM on Pd-decorated sample. This treatment results in dramatically improved hydrogen sorption behavior. In fact, previously inert nanoparticles now exhibit of up to 5.6 wt.%.Real-time diffraction studies using Synchrotron Radiation were carried out during hydrogen desorption on the Pd-decorated nanoparticles. We clearly show that a Mg-Pd intermetallic phase is formed after the first heating treatment and takes active part in the transformation.
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Barros, Fábio Lucas de Oliveira, Maria Cristina da Silva, Francisco José Victor de Castro, and Miodeli Nogueira Júnior. "Marine free-living nematodes in semiarid inland waters." Acta Limnologica Brasiliensia 33 (2021). http://dx.doi.org/10.1590/s2179-975x6520.
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Abstract: Aim This study reports the occurrence of five Nematoda genera previously considered as exclusively marine in inland waters. Methods Sediment samples were taken, weekly, during nine weeks, at a small spring at the Horto Florestal Olho D’Água da Bica, Cuité, PB, ca. 130 km away from the shoreline, between March and May 2016 and fixed in 4% formalin. Nematodes were sorted by manual elutriation through sieves with 0.5 and 0.045 mm and slides were prepared. Results The sediment was classified as coarse sand, with organic matter content ranging between 2.73 and 13.32%, temperature between 27-28°C and constant salinity of 6. From 315 nematodes were sampled among which 18 were from five genera previously thought to be exclusively marine were found. Bolbolaimus was the most common, found in 11.1% of the samples, followed by Gomphionema (3.7%), Rynchonema (7.4%), Prorynchonema (7.4%) e Sabatieria (3.7%), representing 5.7% from total of nematofauna. These genera are widely distributed worldwide, but had never been recorded from inland environments. Conclusions This study contributes with the distributional knowledge of free-living nematodes. From literature data, these genera are not restricted by low salinity, and can be found in estuarine and/or brackish water environments and body water with direct connection to the sea. In any case, the presence of marine genera in this region which is >130 km away from the nearest shoreline is noteworthy, highlighting the importance of studying nematodes from these poorly known semiarid water bodies. These new occurrences raise questionings about the dispersal mechanisms that certified the colonization of these nematodes in the semiarid.
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Bucci, M. G., M. Previtali, M. C. Araujo Dos Anjos, G. Binda, A. Mazzola, F. Airoldi, D. Tavano, et al. "1635 Catch me if you can: a rare case of two-staged MitraClip detachment." European Heart Journal - Cardiovascular Imaging 21, Supplement_1 (January 1, 2020). http://dx.doi.org/10.1093/ehjci/jez319.1025.
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Abstract Case report A 74-year-old man presented with acute heart failure and chronic obstructive pulmonary disease exacerbation. His medical history revealed: anterior myocardial infarction in 2005, treated with primary PCI of left anterior descending coronary artery followed by triple coronary artery bypass, atrial fibrillation, hypertension, diabetes mellitus and obesity. Transthoracic and transesophageal echocardiography (TEE) showed severe functional ischemic mitral regurgitation (MR) with multiple jets, the main one involving the A2-P2 scallops due to asymmetric tethering of the posterior leaflet. The vena contracta diameter (VC) was 8 mm, the effective regurgitant orifice area (EROA) 0.53 cm². Global left ventricular (LV) function was preserved with inferior-posterior wall akinesis. After "Heart Team" discussion, due to high surgical risk, the patient was referred for percutaneous mitral valve repair (PMVR) using MitraClip (MC) system (Abbott Vascular, Illinois). One clip (MC-XTR) was placed at the A3-P3 segments; subsequently, prior to releasing a second clip (MC-XTR), the first one partially detached from the posterior leaflet (Fig A). A third clip (MC-NTR) was implanted medially. The grasp was challenging but at the end of the procedure, the first clip appeared stable and marked reduction of MR was achieved (Fig B). 7 days later, the patient became symptomatic for resting dyspnea and worsened his clinical status. A control 2D-3D TEE revealed a complete detachment of the first implanted clip, visible distally into the LV, trapped in the mitral valve subchordal apparatus (Fig C). This resulted in massive MR (VC: 12 mm, EROA: 0.91 cm²) with an eccentric posteriorly directed regurgitant jet (Fig D). The patient underwent emergency surgical retrieval of the migrated clip, and removal of the torn mitral valve anterior leaflet. The other two clips were also removed (Fig E), and a bioprosthetic mitral valve was implanted. The procedure was completed uneventfully and the patient is in stable conditions at 2-months follow-up. Discussion The constant stretching and whip effect of the mitral leaflets captured between the clips arms, used in PMVR, can lead to complications. Partial clip detachment is a rare adverse event described in ∼0.7-4.9% of patients within 30 days after MC intervention*. We experienced a two-staged MC detachment that is an even rarer complication and requires emergency surgery. In addition, we highlights the usefulness of 3D TEE for early diagnosis and better imaging characterization in patients who develop complications after MC procedure. No conflict of interest. *Puls M, Lubos E, Boekstegers P, von Bardeleben RS, Ouarrak T, Butter C, Zuern CS, Bekeredjian R, Sievert H, Nickenig G, Eggebrecht H, Senges J, Schillinger W. One-year outcomes and predictors of mortality after MitraClip therapy in contemporary clinical practice: results from German transcatheter mitral valve interventions registry. Eur Heart J 2016;37:703-12. Abstract 1635 Figure.