Thematische Bibliographien / PURE SOLVENT MEDIA

Inhaltsverzeichnis

Zeitschriftenartikel
Dissertationen
Buchteile
Konferenzberichte

Auswahl der wissenschaftlichen Literatur zum Thema „PURE SOLVENT MEDIA“

Autor: Grafiati

Veröffentlicht am 18. Mai 2024

Geben Sie eine Quelle nach APA, MLA, Chicago, Harvard und anderen Zitierweisen an

Wählen Sie eine Art der Quelle aus:

Machen Sie sich mit den Listen der aktuellen Artikel, Bücher, Dissertationen, Berichten und anderer wissenschaftlichen Quellen zum Thema "PURE SOLVENT MEDIA" bekannt.

Neben jedem Werk im Literaturverzeichnis ist die Option "Zur Bibliographie hinzufügen" verfügbar. Nutzen Sie sie, wird Ihre bibliographische Angabe des gewählten Werkes nach der nötigen Zitierweise (APA, MLA, Harvard, Chicago, Vancouver usw.) automatisch gestaltet.

Sie können auch den vollen Text der wissenschaftlichen Publikation im PDF-Format herunterladen und eine Online-Annotation der Arbeit lesen, wenn die relevanten Parameter in den Metadaten verfügbar sind.

Zeitschriftenartikel zum Thema "PURE SOLVENT MEDIA"

Khokarale, Santosh Govind, Piotr Jablonski, Dariush Nikjoo, Van Minh Dinh, Ola Sundman, Knut Irgum und Jyri-Pekka Mikkola. „Poly (Vinylidene Difluoride) Polymer in 1-Ethyl-3-methylimidazolium Acetate and Acetic Acid Containing Solvents: Tunable and Recoverable Solvent Media to Induce Crystalline Phase Transition and Porosity“. Sustainable Chemistry 3, Nr. 4 (29.10.2022): 455–74. http://dx.doi.org/10.3390/suschem3040028.

Der volle Inhalt der Quelle

Annotation:

In this report, 1-ethyl-3-methylimidazolium acetate, [EMIM][AcO] ionic liquid (IL) and acetic acid (AA) comprised solvents were used for the thermal treatment of poly (vinylidene difluoride), PVDF. Here, besides the various combinations of IL and AA in solvents, the pure IL and AA were also applied as a solvent upon thermal treatments. The samples obtained after the treatment were analysed for structural and crystalline phase changes, porosity, and molecular weight distribution with various analytical techniques. The Kamlet-Taft parameters measurement of the IL and AA containing solvents with different solvatochromic dyes was also performed to examine their solvent properties and correlate with the properties of the treated PVDF materials. The treatment of PVDF with pure IL results in the formation of highly carbonaceous material due to extensive dehydroflurination (DHF) as well as possibly successive cross-linking in the polymer chains. Upon IL and AA combined solvent treatment, the neat PVDF which composed of both α- and β crystalline phases was transformed to porous and β-phase rich material whereas in case of pure AA the non-porous and pure α-phase polymeric entity was obtained. A combined mixture of IL and AA resulted in a limited the DHF process and subsequent cross-linking in the polymer chains of PVDF allowed the formation of a porous material. It was observed that the porosity of the thermally treated materials was steadily decreasing with increase in the amount of AA in solvents composition and solvent with an AA:IL mole ratio of 2:1 resulted in a PVDF material with the highest porosity amongst the applied solvents. A recovery method for the IL and AA combined solvent after the thermal treatment of PVDF was also established. Hence, with varying the type of solvents in terms of composition, the highly carbonaceous materials as well as materials with different porosities as well as crystalline phases can be obtained. Most importantly here, we introduced new IL and AA containing recoverable solvents for the synthesis of porous PVDF material with the electroactive β-phase.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Bhattarai, Ajaya, Kavita Pathak und Bikash Dev. „Micellization behavior of mixed surfactants in pure water and methanol-water mixed solvent media by density methods“. BIBECHANA 13 (03.12.2015): 114–20. http://dx.doi.org/10.3126/bibechana.v13i0.13887.

Der volle Inhalt der Quelle

Annotation:

The properties of anionic-rich and cationic-rich mixtures of dodecyltrimethylammonium bromide (DTAB) and sodium dodecylsulfate (SDS) in pure water and methanol-water mixed solvent media were studied using density measurements at room temperature. The results showed that density increases with increasing concentration of surfactant mixture over the entire concentration range investigated in pure water and in the given mixed solvent media and which are found to decrease with an increase in the volume fraction of methanol in the solvent composition. The critical micelle concentration increases with the increase in volume fraction of methanol for both the anionic-rich (SDS-DTAB) and cationic-rich (DTAB-SDS) systems.BIBECHANA 13 (2016) 114-120

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Journal, Baghdad Science. „Study the Effect of solvent on the Optical Properties Performance of active polymeric laser media“. Baghdad Science Journal 4, Nr. 3 (02.09.2007): 387–92. http://dx.doi.org/10.21123/bsj.4.3.387-392.

Der volle Inhalt der Quelle

Annotation:

The paper include studies the effect of solvent of dye doped in polymeric laser sample which manufactured in primo press way, which is used as an active (R6G) tunable dye lasers. The remarks show that, when the viscosity of the solvent (from Pure Water to Ethanol), for the same concentration and thickness of the performance polymeric sample is increased, the absorption spectrum is shifts towards the long wave length (red shift), & towards short wave length (blue shift) for fluorescence spectrum, also increased the quantum fluorescence yield. The best result we obtained for the quantum fluorescence yield is (0.882) with thickness (0.25mm) in Ethanol solvent in concentration (2*10-3mole/liter), while when we used the Pure Water as a solvent, we found that the best quantum fluorescence yield is (0.72) at the same thickness & concentration of the sample.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Ghigo, Giovanni, Matteo Bonomo, Achille Antenucci, Chiara Reviglio und Stefano Dughera. „Copper-Free Halodediazoniation of Arenediazonium Tetrafluoroborates in Deep Eutectic Solvents-like Mixtures“. Molecules 27, Nr. 6 (15.03.2022): 1909. http://dx.doi.org/10.3390/molecules27061909.

Der volle Inhalt der Quelle

Annotation:

Deep Eutectic Solvent (DES)-like mixtures, based on glycerol and different halide organic and inorganic salts, are successfully exploited as new media in copper-free halodediazoniation of arenediazonium salts. The reactions are carried out in absence of metal-based catalysts, at room temperature and in a short time. Pure target products are obtained without the need for chromatographic separation. The solvents are fully characterized, and a computational study is presented aiming to understand the reaction mechanism.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Hirotsu, Shunsuke. „Phase Transition of a Polymer Gel in Pure and Mixed Solvent Media“. Journal of the Physical Society of Japan 56, Nr. 1 (15.01.1987): 233–42. http://dx.doi.org/10.1143/jpsj.56.233.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Minò, Antonio, Giuseppe Cinelli, Francesco Lopez und Luigi Ambrosone. „Optical Behavior of Nile Red in Organic and Aqueous Media Environments“. Applied Sciences 13, Nr. 1 (03.01.2023): 638. http://dx.doi.org/10.3390/app13010638.

Der volle Inhalt der Quelle

Annotation:

A simple model is proposed to calculate the dimerization constant of a dye in non-aqueous solvents. Alkan-1ols of the formula H–(CH2)n–OH are used to study the spectroscopic behavior of Nile Red dye. The number n varied from 1 to 8 to modulate the medium hydrophobicity. Generally, Nile red is used to localize lipid droplets within cells. This molecule is non-fluorescent in water and other polar solvents but undergoes fluorescence enhancement and large absorption and emission blue shifts in non-polar environments. The calculated equilibrium constants suggest that the aggregation process is solvent-assisted. The absorption and fluorescence emission spectra reveal a marked red shift, which is studied by breaking the wavelength of the maximum band into two terms, showing the contribution of the solvent and the effect of the dye concentration. Both contributions were investigated as a function of the number n, and it was found that alkan-1ols with large n tend to aggregate and produce a smaller red shift. Conversely, it was also noticed that short-chain alkan-1ols stabilize the excited state of the dye via H-bond and the red shift increases. The hydrophilicity of the medium was found to be modulated by adding pure water, in a controlled way, to the binary systems dye–H–(CH2)n–OH (n = 1–8). The quantification of solvent hydrophilicity is described with the ratio R = water moles/alcohol moles. From this investigation, we realized that the absorption spectra values are strictly connected with the R parameter. In this context, we realized that fluorescence emission spectra allow us to determine the adjustable parameters.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Hassan, Ahmed, H. A. Azab, S. A. El Gyar und Z. A. Khafagy. „Medium effect on the second-stage dissociation constant of N-(2-acetamido)imino diacetic acid (H2ADA)“. Canadian Journal of Chemistry 70, Nr. 6 (01.06.1992): 1684–87. http://dx.doi.org/10.1139/v92-211.

Der volle Inhalt der Quelle

Annotation:

The second-stage dissociation constant values of N-(2-acetamido)imino diacetic acid (H2ADA) were determined at 25 ± 0.1 °C by potentiometric titration in different mixed-solvent mixtures (methanol, ethanol, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetone, and dioxane). It was observed that the pKa value is slightly influenced as the solvent is enriched in methanol and ethanol, and remains practically constant in the presence of different amounts of DMF and DMSO. A prounounced change in the pKa value was observed as the solvent is enriched in acetone or dioxane. These results are discussed in terms of various solvent characteristics. It is concluded that the electrostatic effect has only a relatively small influence on the dissociation equilibrium of the imino group [Formula: see text]. Other solvent effects such as solvent basicity, different stabilization of the free base of the conjugate acid by hydrogen bonding interactions in aquoorganic solvent media relative to pure aqueous media, as well as proton–solvent interaction play an important role in the acid dissociation equilibrium.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Su, Chien-You, Han-Liou Yi, Li-Duan Tsai, Ming-Chou Chen und Chi-Chung Hua. „Solution properties of imidazolium-based amphiphilic polyelectrolyte in pure- and mixed-solvent media“. Physical Chemistry Chemical Physics 21, Nr. 7 (2019): 3960–69. http://dx.doi.org/10.1039/c8cp07027j.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Bhattarai, Ajaya, Sujit Kumar Shah, Ashok Kumar Yadav und Janak Adhikari. „Effect of solvent composition on the critical micelle concentration of sodium deoxycholate in ethanol-water mixed solvent media“. BIBECHANA 9 (10.12.2012): 63–68. http://dx.doi.org/10.3126/bibechana.v9i0.7176.

Der volle Inhalt der Quelle

Annotation:

The precise measurement of the specific conductivity of sodium deoxycholate in pure water and ethanolwater mixed solvent media containing 0.10 and 0.20 volume fraction of ethanol at 303.15 K are reported. The concentration were varied from ~ 0.01 mol L-1 to ~ 0.0002 mol L-1.The conductivity of sodium deoxycholate decreases with the increase in the volume fraction of ethanol. The critical micelle concentration of sodium deoxycholate increases with the increase in the volume fraction of ethanol. DOI: http://dx.doi.org/10.3126/bibechana.v9i0.7176 BIBECHANA 9 (2013) 63-68

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Bhattarai, Ajaya, Sujit Kumar Shah und Ashok Kumar Yadav. „Effect of Solvent Composition on the Critical Micelle Concentration of Cetylpyridinium Chloride in Ethanol-Water Mixed Solvent Media“. Nepal Journal of Science and Technology 13, Nr. 1 (21.01.2013): 89–93. http://dx.doi.org/10.3126/njst.v13i1.7446.

Der volle Inhalt der Quelle

Annotation:

The accurate measurement of the specific conductivity of cetylpyridinium chloride in pure water and ethanol-water mixed solvent media containing 0.10, 0.20, 0.30 and 0.40 volume fraction of ethanol at room temperature are reported. The concentrations were varied from ~ 0.005 mol l-1 to ~ 0.0002 mol l-1.The conductivity of cetylpyridinium chloride decreases with the increase in the volume fraction of ethanol. The critical micelle concentration of cetylpyridinium chloride increases with the increase in the volume fraction of ethanol. Nepal Journal of Science and Technology Vol. 13, No. 1 (2012) 89-93 DOI: http://dx.doi.org/10.3126/njst.v13i1.7446

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Mehr Quellen

Dissertationen zum Thema "PURE SOLVENT MEDIA"

Brahman, Dhiraj. „PHYSICO-CHEMICAL STUDIES OF SOME SCHIFF BASE COMPLEXES OF TRANSITION METALS IN PURE AND MIXED SOLVENT MEDIA“. Thesis, University of North Bengal, 2013. http://hdl.handle.net/123456789/973.

Der volle Inhalt der Quelle

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Buchteile zum Thema "PURE SOLVENT MEDIA"

Back, Thomas G. „Oxidations with selenium reagents“. In Organoselenium Chemistry, 93–112. Oxford University PressOxford, 1999. http://dx.doi.org/10.1093/oso/9780198501411.003.0005.

Der volle Inhalt der Quelle

Annotation:

Abstract Selenium dioxide is an oxidizing agent that was one of the earliest selenium reagents to find widespread application in organic synthesis, with early examples dating from the 1930s. Its properties, preparation and synthetic applications have been the subjects of both early1 and more recent2 reviews. Several methods exist for its preparation by the oxidation of elemental selenium, and it is also commercially available. Pure selenium dioxide is a white, crystalline solid, but the reagent sometimes has a pink coloration, probably because of the presence of elemental selenium. It can be purified by sublimation. It has limited solubility in most organic solvents and must generally be used in aqueous or alcohol media. In many applications, the active oxidant is probably selenious acid (H2SeO3), the hydrolysed form of the dioxide. Selenium dioxide is toxic and so must be handled with appropriate care. Although the compound itself is not malodorous, by-products formed during oxidations of organic substrates are often volatile and highly unpleasant.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Konferenzberichte zum Thema "PURE SOLVENT MEDIA"

Yang, Daoyong, Yunlong Li und Desheng Huang. „Quantification of Phase Behaviour and Physical Properties of Alkane Solvents/CO2/ Water/Heavy Oil Systems under Equilibrium and Nonequilibrium Conditions“. In SPE Canadian Energy Technology Conference. SPE, 2022. http://dx.doi.org/10.2118/208968-ms.

Der volle Inhalt der Quelle

Annotation:

Abstract The hybrid steam-solvent injection has been considered as a promising technique for enhancing heavy oil/bitumen recovery, while its main mechanisms including the heat transferred and dissolution of solvents (e.g., C3H8, C4H10, CO2, N2, and DME) into heavy oil/bitumen to reduce its viscosity and swell it are closely related to the phase behaviour of the solvents/water/heavy oil systems. To allow the seamless integration with the existing reservoir simulators, the traditional cubic equations of state (i.e., SRK EOS and PR EOS) have been modified and improved to accurately quantify the phase behaviour and physical properties of the aforementioned systems under equilibrium and nonequilibrium conditions. Firstly, a huge database has been built to develop the corresponding alpha functions by minimizing the deviation between the measured and calculated vapour pressures for water as well as nonhydrocarbon and hydrocarbon compounds available from the public domain. Such obtained alpha functions are further validated with enthalpy of vaporization for pure substances, and then the reduced temperature has been optimized and the eccentric factor has been redefined. Finally, a pressure-implicit strategy has been developed to optimize the binary interaction parameters (BIPs) by treating heavy oil as one pseudocomponent (PC) or multiple PCs. Also, the contributions of each solvent to the aforementioned systems have been compared and analyzed within a consistent and unified framework. In addition to new alpha functions for hydrocarbons and water, respectively, the reduced temperature is found to have its optimum value of 0.59 for the two equations of state (EOSs), while 0.60 is recommended for practical use. Such improved EOSs have been further employed to reproduce the experimentally measured multiphase boundaries (or pseudo-bubble-point pressures), density, viscosity, (mutual) solubility, and preferential mass transfer for the aforementioned mixtures under equilibrium and nonequilibrium conditions. The swelling effect for the heavy oil can be enhanced due to the addition of C3H8 and/or C4H10 or their mixtures into the CO2 stream. Due to the existence of water, isenthalpic flash leads to more accurate quantification of multiphase boundaries and physical properties for the hybrid solvent-thermal processes. Each component of a binary or ternary gas mixture is found to diffuse preferentially into heavy oil at high pressures and elevated temperatures in the absence and presence of porous media, while each of them is found to exsolve differently from gas-saturated heavy oil under nonequilibrium conditions.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Larsen, Marvin E. „Use of Contact Resistance Algorithm to Implement Jump Boundary Conditions for the Radiation Diffusion Approximation“. In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72561.

Der volle Inhalt der Quelle

Annotation:

Thermal conduction codes can be used as solvers for the diffusion approximation for radiation heat transfer. Energy fluxes and temperature distributions that result from thermal radiation in an optically-thick participating medium can be estimated. Allowing dependence on temperatures from either side of the interface, a contact resistance algorithm can be used to implement “jump” (or slip) boundary conditions appropriate for the diffusion approximation in solving the radiation transfer equation. For steady, pure radiation (no conduction) systems analytical expressions exist to specify the temperature in the radiating medium at the wall as a function of the wall temperature, wall emissivity, and extinction coefficient. Radiation and conduction solutions for gray, absorbing/emitting and conducting media bound by diffuse surfaces for the simple case of the steady planar layer are considered. Reference solutions are developed by detailed zone-methods solving the coupled differential forms of both the radiation and conduction heat transfer equations. From the reference solutions, empirical relations are developed for surface resistance as functions of the local wall and adjacent media temperatures, the wall emissivity, the absorptivity, and the thermal conductivity of the medium. Performance of the approximate solution is compared to the reference solutions.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Gairola, A., Hitesh Bindra, Gaurav Agarwal und Suneet Singh. „Lattice Boltzmann Method for Solving Time-Dependent Radiation Transport and Reactor Criticality Problems“. In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60058.

Der volle Inhalt der Quelle

Annotation:

The recently developed lattice Boltzmann equation (LBE) framework [1] for radiation transport is extended to solve time-dependent nonequilibrium neutron transport problems. Dynamics of radiation and material energy exchange is modeled by coupling the radiation transport equation with the material energy equation in a one-dimensional isotropically scattering homogenous medium. The LBE equations are obtained for corresponding radiative or neutron transport in constant source and reactor criticality search problems. Furthermore, a two-dimensional D2Q8 & D2Q16 LBEs are proposed for solving the time-dependent neutron transport equation in a heterogenous media (e.g., a checkerboard lattice with pure scattering and absorbing cells). The results obtained with LBE are in good agreement with the existing discrete ordinate method results for the benchmark problem.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Xiao, Yumin, R. S. Amano, E. K. Lee, Youn-Suk Choi und Jianhui Xie. „A Non-Source Term Methodology in Simulation of Solidification“. In ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33222.

Der volle Inhalt der Quelle

Annotation:

In this paper a non-source term method is developed to solve the energy equation. In this new method the discrete form of the energy equation remains the same and no extra source term is introduced. The mushy-zone is treated as a porous media during solidification. This method is incorporated into the existing finite volume based CFD code. Test cases analyzed in this paper include solidification of pure metal, pure metal solidification with natural convection due to the buoyancy, and binary alloy mushy flow problem with variable Cp. The calculated results are in good agreements with available published data. This method can be applied to simulate a wide range of melting/solidification processes.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Johnson, R. V., und A. R. Tanguay. „Optical beam propagation in anisotropic media“. In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1985. http://dx.doi.org/10.1364/oam.1985.fs1.

Der volle Inhalt der Quelle

Annotation:

Optical diffraction in media with arbitrary inhomogeneous anisotropies (including linear birefringence and/or optical activity) is characterized by pronounced polarization effects. These effects have typically been analyzed by the coupled wave formalism. An alternative analytical technique is the anisotropic optical beam propagation method (BPM) first proposed by Thylen and Yevick.1 The BPM is a highly intuitive approach to solving the light propagation equation in an optically inhomogeneous medium. The coupled wave approach is preferred for spectrally pure inhomogeneities (simple gratings), whereas the BPM is the preferred algorithm for spectrally rich inhomogeneities (image modulated gratings). The BPM replaces the distributed diffraction problem with an equivalent lumped element approximation consisting of infinitesimally thin phase and polarization modulation planes separated by optically homogeneous layers. The evolution of the light profile both in the near field and in the plane wave spectrum can be monitored as the light beam propagates through the anisotropic medium. In this paper we extend the analysis to include optical activity for modeling volume grating in materials such as bismuth silicon oxide. We also perform detailed numerical experiments to assess which classes of problem are better suited for the coupled wave formalism and which for the BPM formalism.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Pesavento, Francesco, Dariusz Gawin, Bernhard A. Schrefler und Marcin Koniorczyk. „Modelling Chemical Processes in Cement Based Materials by Means of Multiphase Porous Media Mechanics“. In ASME 2012 11th Biennial Conference on Engineering Systems Design and Analysis. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/esda2012-82932.

Der volle Inhalt der Quelle

Annotation:

A general approach to modelling chemical degradation processes in cement based materials, due to combined action of hygro-thermal, chemical and mechanical loads, is presented. Mechanics of multiphase porous media and damage mechanics are applied for this purpose. The mass-, energy- and momentum balance equations, and constitutive and physical relations are briefly presented, and then numerically solved with the finite element method. Several examples of the model application for analysing ions transport and degradation processes of concrete due to chemical attack of pure water, salt crystallisation and alkali-silica reaction are presented and discussed.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Huang, Y., Z. Lei, K. Lipnikov, J. D. Moulton, M. R. Sweeney, J. D. Hyman, E. Knight und P. H. Stauffer. „Modeling Coupled Thermo-Hydro-Mechanical-Chemical Processes in Subsurface Geological Media“. In 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0320.

Der volle Inhalt der Quelle

Annotation:

ABSTRACT The complex coupling interaction phenomena among rock mechanics, fluid flow, heat transfer and geochemical reactions has become a critical topic in complex subsurface systems including the production of unconventional oil and gas. In this paper, we introduce a fully coupled Thermo-Hydro-Mechanical-Chemical (THMC) framework that is being developed at Los Alamos National Laboratory (LANL). The framework integrates four LANL-developed codes: HOSS, Amanzi, dfnWorks and InyanCC. HOSS simulates deformation of the rock matrix as well as the opening, closing and shear sliding in the discrete fractures (mechanics), while Amanzi solves subsurface multiphase flow and reactive transport, dfnWorks generates meshes with complex discrete fracture networks, and InyanCC links the mechanics and flow solvers while controlling the whole simulation processes. The advantages of this coupling framework are: 1) it is based on hybrid continuum-discontinuum approaches which overcomes the limitations seen with pure continuum assumptions; 2) both mechanics and subsurface flow solvers are fully parallelized for distributed memory systems which allows the users to simulate large scale problems on HPC clusters. Different selected benchmarking problems are simulated using this THMC framework. The results show good agreement with the analytical solutions, which verifies the accuracy of the framework. INTRODUCTION Current applications of geotechnical engineering and geo-energy in the subsurface rely significantly on complex coupling process among rock mechanics, fluid flow, heat transfer and geochemical reactions, including geothermal production, unconventional oil and gas production and underground nuclear explosions. Hence, Modeling Thermo-Hydro-Mechanical-Chemical (THMC) processes is essential in understanding the coupled processes in subsurface geological media. Fully addressing the computational challenge of coupled THMC process simulation has been exacerbated by the inability to simulate coupled processes in both the rock matrix and discrete fractures. However, modern subsurface simulators taking advantage of the high-performance computation have been proposed to overcome these challenging problems. Cheng, 2016; Rutqvist et al., 2001; and Wang, 2000 proposed different approaches for modeling the evolution of pressure, stress, and temperature fields in porous media, including equations for pressure diffusion, mechanical equilibrium, and energy transport. Rutqvist and Stephansson (2003) introduced a coupled THM model based on sub-grid scale fracture networks. Min and Jing (2003) reported numerical simulations of hydro-mechanical coupling in fracture networks. These models capture the contribution of discrete fracture deformation to permeability anisotropy through the effective properties such as permeability and porosity. However, these methods have limitation in modeling time-evolving large scale THM system when the characteristic length of network structures is much larger than the grid block scale.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Kumar, Anil, und Younus Sheikh. „An Assessment of Health Hazards in Valves for Gaseous Oxygen Service: Sources and Preventive Measures“. In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-86018.

Der volle Inhalt der Quelle

Annotation:

Oxygen content in air is approximately 21% by volume. With many industrial uses, mainly in the manufacture of steel and chemicals, for metal cutting, welding ,hardening & scarfing, it is being transported as a non-liquefied gas at pressures of 138 bar (13800000 Pa) or above, also as a cryogenic fluid at pressures and temperatures below 13.8bar (1380000 Pa) & −146.5°C (126.65K). Commonly we found air separation plants produce ultra-pure oxygen (> 99.9% purity) via liquefaction of atmospheric air and separation of the oxygen by fractionation and thereby transported to the needy areas via pipelines. The research efforts directed towards technical assessment to establish the correlations between valve construction and turbulence and solving the complications in the transported ultra-pure oxygen gas in the pipelines and through mounted valves. Hence, it is necessary to study the performance, complexities and fire hazards associated with the valves transporting it and the preventive measures to avoid any catastrophic failure in ultra-pure gaseous oxygen services. The study was conducted on two isolation valves — each of ball and globe of relative size. It was realized that velocities of the ultrapure gaseous oxygen on the impingement sites inside the valve are beyond the safe limit as recommended by European Industrial Gas Association (EIGA) [4] and various other prominent industrial gas manufacturers. Moreover, globe valve gave relatively less turbulence and velocity at initial opening of the valve. The study revealed that majority of health hazards & accidents on industrial usage of ultra-pure gaseous oxygen media are the result of the inadequate awareness of the degreasing or cleaning and optimum material selection and construction of the valve and fittings on the industrial pipeline.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Feng, Yongchang, Huixiong Li und Can Cheng. „Double MRT-Lattice Boltzmann Simulation of Natural Convection Melting in a Rectangular Cavity“. In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17205.

Der volle Inhalt der Quelle

Annotation:

In this letter, a double multiple relaxation time (MRT) lattice Boltzmann method (LBM) based on double distribution lattice Boltzmann model is developed for numerical simulations of solid-liquid phase change. In contrast to previous lattice Boltzmann models, we solve the flow and temperature fields using the MRT-D2Q9 model and the MRT-D2Q5 model, respectively. The one-dimensional conduction melting and two-dimensional convection melting in a rectangular cavity for pure substance are investigated using the proposed model. Simulation results agree well with analytical solutions and scaling laws. In addition, temperature and liquid fraction fields suggest that natural convection has important influence on total melting process. We conclude by showing that the developed model is a promising tool to investigate solid-liquid phase change in complex media and geometries.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Fraces, Cedric G., und Hamdi Tchelepi. „Physics Informed Deep Learning for Flow and Transport in Porous Media“. In SPE Reservoir Simulation Conference. SPE, 2021. http://dx.doi.org/10.2118/203934-ms.

Der volle Inhalt der Quelle

Annotation:

Abstract We present our progress on the application of physics informed deep learning to reservoir simulation problems. The model is a neural network that is jointly trained to respect governing physical laws and match boundary conditions. The methodology is hereby used to simulate a 2-phase immiscible transport problem (Buckley-Leverett). The model is able to produce an accurate physical solution both in terms of shock and rarefaction and honors the governing partial differential equation along with initial and boundary conditions. We test various hypothesis (uniform and non-uniform initial conditions) and show that with the proper implementation of physical constraints, a robust solution can be trained within a reasonable amount of time and iterations. We revisit some of the limitations presented in previous work [1] and further the applicability of this method in a forward, pure hyperbolic setup. We also share some practical findings on the application of physics informed neural networks (PINN). We review various network architectures presented in the literature and show tips that helped improve their convergence and accuracy. The proposed methodology is a simple and elegant way to instill physical knowledge to machine-learning algorithms. This alleviates the two most significant shortcomings of machine-learning algorithms: the requirement for large datasets and the reliability of extrapolation. The principles presented can be generalized in innumerable ways in the future and should lead to a new class of algorithms to solve both forward and inverse physical problems.

APA, Harvard, Vancouver, ISO und andere Zitierweisen

Wir bieten Rabatte auf alle Premium-Pläne für Autoren, deren Werke in thematische Literatursammlungen aufgenommen wurden. Kontaktieren Sie uns, um einen einzigartigen Promo-Code zu erhalten!