65 research outputs found
Carbon Dioxide Capture in Metal–Organic Frameworks
No full textAbstract not availableKenji Sumida, David L. Rogow, Jarad A. Mason, Thomas M. McDonald, Eric D. Bloch, Zoey R. Herm, Tae-Hyun Bae, Jeffrey R. Lon
Assessment of Cavitation Erosion with a Multiphase Reynolds-Averaged Navier-Stokes Method
No full textCavitation erosion is one of the remarkable catastrophic consequences of cavitation. Predicting the cavitation aggressiveness quantitatively and predicting the most probable location of cavitation erosion are complex problems that currently still motivate an important amount of basic and applied research in the fields of hydrodynamics, physics and metallurgy. The work addresses two main issues: Numerical simulations of cavitating flows over hydrofoils; and an assessment of the risk of cavitation erosion on the surface of hydrofoils. The capability of the multiphase RANS method to predict the relevant and critical unsteady cavitation dynamics in the flow over hydrofoils has been investigated on two NACA hydrofoils (NACA0015 hydrofoil and NACA0018-45 hydrofoil) in the 2D and 3D domain, respectively. It was found that the large-scale structures and the typical unsteady cavitation dynamics predicted by the RANS method implemented in FLUENT were in fair agreement with the observations from experiments. To find the best criteria for an assessment of the risk of cavitation erosion, current erosion risk assessment models and methodologies that use computational fluid dynamic tools or experimental results as input were reviewed and evaluated. An erosion intensity function was proposed based on the mean value of those values of the time derivative of the local pressure that exceeds a certain threshold, and was evaluated for the NACA0015 hydrofoil and NACA0018-45 hydrofoil. A good correlation was found between the locations with the high erosion risk obtained from the computations and the damage area observed from paint tests.Marine & Transport TechnologyMechanical, Maritime and Materials Engineerin
Processing real time road traffic data from probe vehicles using a hybrid micro-macro road traffic model
No full textThe utilisation of probe vehicles is an advancing technique for real time road traffic monitoring. A hybrid stochastic road traffic model has been developed based on micro and macro traffic theories to process received probe vehicle data and extract relevant information for DTM purposes. With Bayes' rule for conditional probabilities, the hybrid micro-macro model is analysed. The pdfs for individual as well as the mean speed is used, together with the qvdiagram. With different estimators the actual road link speed is estimated, based on N probe messages for the distinct applications of ATIS and ATMS.Applied SciencesElectrical EngineeringTelecommunications and Traffic Control Systems Grou
Numerical methods for the implementation of the Cahn-Hilliard equation in one dimension and dynamic boundary condition in two dimensions
No full textThis project can be divided into two parts. The goal of the first part is to numerically implement the Cahn-Hilliard equation in one dimension both explicitly and implicitly. This will be done using Matlab. The goal of the second part is to validate the coupled Cahn-Hilliard-Navier-Stokes equation and the dynamic boundary condition for moving contact lines of (Carlson et al, 2011, p.9) by considering a two-dimensional spreading droplet case. This will be done using the CFD software OpenFOAM. In Chapter 1, the theory of positive and negative diffusion, including the normal diffusion equation and the Cahn-Hilliard equation, are discussed. Some background is given regarding the thermodynamics of the Cahn-Hilliard equation and its steady-state solution. After that, the theory of the coupled Cahn-Hilliard-Navier-Stokes equation, the dynamic boundary condition for moving contact lines and the case which is implemented in OpenFOAM, are discussed. In Chapters 2 and 3, the diffusion equation and the Cahn-Hilliard equation are implemented in one dimension, using the Euler Forward scheme. In implementing the Cahn-Hilliard equation, two different discretizations are used, of which only one gives the desired results. Next, an extensive stability analysis is done, using a linearization of the Cahn-Hilliard equation as well as numerical experiments. The stability condition is increasingly severe with increasing interface width. Regarding the results of the evolving interface, a qualitative analysis is done which discusses three subjects: the deviation of the solutions with the steady-state solution, the interface width for different parameters and grid sizes and the interface overshoot, which is an unphysical appearence. In Chapter 4, two semi-implicit methods and one implicit iterative method, are discussed. The implementations of the two semi-implicit methods, Implicit-Explicit (ImEx) and Modified Furihata, are succesful and their stability conditions are better than the stability condition of the Euler Forward scheme, for most interface widths. The results regarding the evolving interface are nearly identical to the results of the Euler Forward scheme, therefore the qualitative analysis is also similar. The implicit iterative method, which involves the use of the G\^ateaux derivative, has not been succesfully implemented, eventhough two different discretizations are used. The results regarding the evolving interface are behaving in a positive diffusive way, which results in a flattening interface with time. In Chapter 5, the coupled Cahn-Hilliard-Navier-Stokes equation and a dynamic boundary condition for moving contact lines are used to model a spreading droplet on a flat surface. The implemented model is validated using different cases in which the steady-state contact angle and the friction factor of the surface varies. Next, parametric studies are done regarding the interface width, the surface tension and the ratio of the surface tension and the friction factor. The conclusions are that the modeled system differs too much from the system in literature to make an absolute comparison but, qualitatively, the model behaves as expected.Transport PhenomenaChemical EngineeringApplied Science
Согласование интересов страны-реципиента и трудящихся-мигрантов
No full textThe contribution is devoted actual problems of external labour migration in the Russian Federation. The author construction of system of necessary conditions for the optimum coordination of interests of the country-recipient and workers-migrants is offered. Also actual problems of a migratory policy are considered, blanks in the legislation of two countries concerning labour migration are opened.Статья посвящена актуальным проблемам внешней трудовой миграции на примере Российской Федерации и Республики Таджикистан. Автором предложено построение системы необходимых условий для оптимального согласования интересов страны-реципиента и трудящихся-мигрантов. Также рассмотрены актуальные проблемы миграционной политики, раскрыты пробелы в законодательстве двух стран относительно трудовой миграции
Metal-organic frameworks as adsorbents for hydrogen purification and precombustion carbon dioxide capture
No full textSelected metal−organic frameworks exhibiting representative properties—high surface area, structural flexibility, or the presence of open metal cation sites—were tested for utility in the separation of CO2 from H2 via pressure swing adsorption. Single-component CO2 and H2 adsorption isotherms were measured at 313 K and pressures up to 40 bar for Zn4O(BTB)2 (MOF-177, BTB3− = 1,3,5-benzenetribenzoate), Be12(OH)12(BTB)4 (Be-BTB), Co(BDP) (BDP2− = 1,4-benzenedipyrazolate), H3[(Cu4Cl)3(BTTri)8] (Cu-BTTri, BTTri3− = 1,3,5-benzenetristriazolate), and Mg2(dobdc) (dobdc4− = 1,4-dioxido-2,5-benzenedicarboxylate). Ideal adsorbed solution theory was used to estimate realistic isotherms for the 80:20 and 60:40 H2/CO2 gas mixtures relevant to H2 purification and precombustion CO2 capture, respectively. In the former case, the results afford CO2/H2 selectivities between 2 and 860 and mixed-gas working capacities, assuming a 1 bar purge pressure, as high as 8.6 mol/kg and 7.4 mol/L. In particular, metal−organic frameworks with a high concentration of exposed metal cation sites, Mg2(dobdc) and Cu-BTTri, offer significant improvements over commonly used adsorbents, indicating the promise of such materials for applications in CO2/H2 separations
Students' perceptions of the nature of evolutionary theory
No full textThis study explored how some college students understand the nature of the theory of evolution and how they evaluate its scientific status. We conducted semistructured interviews with 15 college biology seniors in which we asked them to explain why they think evolution assumes the status of a scientific theory, how it compares to other scientific theories, and what criteria do they use to determine if an explanation is scientific or not. Students' responses encompassed five themes that include evidence, certainty, experimentation, method of theory generation, and prediction. Those themes focused on the theory's empirical dimension which seemed to be derived from a generic and simplistic model of physical science theories that valued direct evidence. Demanding that evolutionary theory conform to this model reveals a misunderstanding of its nature. This misunderstanding was expressed in relation to aspects of methodology, explanation, and prediction. The findings underscore the need for using explicit discipline- and context-specific approaches to teaching and learning about scientific theories. © 2005 Wiley Periodicals, Inc.Abd-El-Khalick F., 2001, J SCI TEACHER ED, V12, P215, DOI DOI 10.1023-A:1016720417219; Abd-El-Khalick F, 2000, INT J SCI EDUC, V22, P665, DOI 10.1080-09500690050044044; Abd-El-Khalick F, 2000, J RES SCI TEACH, V37, P1057, DOI 10.1002-1098-2736(200012)37:101057::AID-TEA33.0.CO;2-C; ALEIXANDRE MJ, 1992, INT J SCI ED, V14, P51; American Association for the Advancement of Science, 1990, SCI ALL AM; Anderson DL, 2002, J RES SCI TEACH, V39, P952, DOI 10.1002-tea.10053; Bartholomew H, 2004, SCI EDUC, V88, P655, DOI 10.1002-sce.10136; BISHOP BA, 1990, J RES SCI TEACH, V27, P415, DOI 10.1002-tea.3660270503; Brem SK, 2003, SCI EDUC, V87, P181, DOI 10.1002-sce.10105; Brickhouse N. W., 2002, SCI ED, V11, P573, DOI 10.1023-A:1019693819079; Cartwright N., 1983, HOW LAWS PHYS LIE; CLOUGH M, 1995, AM BIOL TEACH, V5, P401; Dagher ZR, 2004, INT J SCI EDUC, V26, P735, DOI 10.1080-0950069032000138806; Dagher ZR, 1997, J RES SCI TEACH, V34, P429, DOI 10.1002-(SICI)1098-2736(199705)34:5429::AID-TEA23.0.CO;2-S; Driver R., 1996, YOUNG PEOPLES IMAGES; Duschl R. A., 1990, RESTRUCTURING SCI ED; Elgin M, 2003, PHILOS SCI, V70, P1380, DOI 10.1086-377415; Ferrari M, 1998, INT J SCI EDUC, V20, P1231, DOI 10.1080-0950069980201005; Fysh R., 1998, RES SCI EDUC, V28, P399, DOI 10.1007-BF02461507; Ghiselin Michael T., 1997, METAPHYSICS ORIGIN S; GIBBS A, 1992, AM BIOL TEACH, V54, P137; DEMASTES SS, 1995, SCI EDUC, V79, P637, DOI 10.1002-sce.3730790605; Griffiths A. K., 1995, SCH SCI MATH, V95, P248, DOI DOI 10.1111-J.1949-8594.1995.TB15775.X; JACKSON D, 1995, J RES SCI TEACH, V34, P93; Khishfe R, 2002, J RES SCI TEACH, V39, P551, DOI 10.1002-tea.10036; Leach J, 2003, SCI EDUC, V87, P831, DOI 10.1002-sce.10072; Lemke J. L, 1990, TALKING SCI; Mahner M., 1997, FDN BIOPHILOSOPHY; Matthews M., 2000, TIME SCI ED TEACHING; Mayr E., 1982, GROWTH BIOL THOUGHT; Mayr E., 2001, WHAT EVOLUTION IS; MCCOMAS W, 1909, NATURE SCI SCI ED RA, P3; McComas W. F., 1998, NATURE SCI SCI ED RA, P41; Meyling H., 1997, SCI EDUC, V6, P397, DOI 10.1023-A:1017908916810; National Academy of Sciences, 1998, TEACH EV NAT SCI; National Research Council, 1996, NAT SCI ED STAND; NORRIS S, 1995, J RES SCI TEACH, V22, P817; Osborne J, 2003, J RES SCI TEACH, V40, P692, DOI 10.1002-tea.10105; Passmore C, 2002, J RES SCI TEACH, V39, P185, DOI 10.1002-tea.10020; Root-Bernstein R., 1984, P64; Rose Steven, 1998, LIFELINES BIOL DETER; Roth WM, 1997, J RES SCI TEACH, V34, P145, DOI 10.1002-(SICI)1098-2736(199702)34:2145::AID-TEA43.0.CO;2-T; Rudolph JL, 2000, J CURRICULUM STUD, V32, P403, DOI 10.1080-002202700182628; Ruse M., 1988, PHILOS BIOL TODAY; RYAN AG, 1992, SCI EDUC, V76, P559, DOI 10.1002-sce.3730760602; Sandoval WA, 2003, J RES SCI TEACH, V40, P369, DOI 10.1002-tea.10081; Schwab J. J., 1962, TEACHING SCI, P1; Shipman HL, 2002, SCI EDUC, V86, P526, DOI 10.1002-sce.10029; Sinatra GM, 2003, J RES SCI TEACH, V40, P510, DOI 10.1002-tea.10087; Sober E., 1993, PHILOS BIOL; SOLOMON J, 1992, J RES SCI TEACH, V29, P409, DOI 10.1002-tea.3660290408; Stewart J, 2001, SCI EDUC, V85, P207, DOI 10.1002-sce.1006; Strauss A. L., 1987, QUALITATIVE ANAL SOC34323
Dostoevsky's traditions in the novel “Doctor Faustus” by T. Mann
No full textThis paper makes analyses of the different research points of the Dostoevsky's traditions in the novel “Doctor Faustus” by T. Mann . On this case, Reception of ideas of F. Dostoevsky's in the novel “Doctor Faustus” by T. Mann . Finally, conclusions of the author done to make further analyses on the topic
On the issue of territorial construction of the system of courts of general jurisdiction
No full textКісіль З. Р. До питання територіальної побудови системи судів загальної юрисдикції / З. Р. Кісіль // Наукові записки Львівського університету бізнесу та права. - 2013. - Вип. 10. - С. 186-189.У статті проаналізовано принцип територіальності як один із передбачених Конституцією
України принципів побудови системи судів загальної юрисдикції. Запропоновано авторські
визначення понять «апеляційний округ», «судовий округ», які дають підстави для перегляду
напрямів побудови судової системи України. In the article the principle of territorialness as one of the stated by Constitution of Ukraine principles of
construction of general jurisdiction courts system is analyzed. Author determinations of concepts «appellate
district», «judicial district» are offered, that forms the ground for the revision of directions of formation of
judicial system of Ukraine
CO2/CH4, CH4/H-2 and CO2/CH4/H-2 separations at high pressures using Mg-2(dobdc)
No full textHigh-pressure separations of binary and ternary mixtures of CO2, CH4, and H2 are relevant to carbon dioxide capture as well as hydrogen and natural gas purification. Metal-organic frameworks represent a class of porous materials that could be used to accomplish these separations, and Mg2(dobdc) (dobdc4− = 1,4-dioxido-2,5-benzenedicarboxylate), also sometimes referred to as Mg-MOF-74 or CPO-27-Mg, is an especially lightweight metal-organic framework with a high concentration of coordinatively-unsaturated metal sites decorating its interior surfaces. High pressure CH4 adsorption isotherms presented here, together with CO2 and H2 adsorption behavior, are analyzed using the Ideal Adsorbed Solution Theory to model CO2/CH4, CH4/H2, and CO2/CH4/H2 mixture separations using Mg2(dobdc). The selectivities, working capacities and breakthrough performances for these three mixtures are reported, and Mg2(dobdc) is shown to outperform zeolite 13X in each scenario
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