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570672. Steady creeping flow of an inelastic fluid past a rigid sphere
- Creator:
- Sacheti, Nirmal C. and Chandran, Pallath
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- non-Newtonian fluid, Reiner-Philippoff fluid, creeping flow, stream function, drag, nenewtonská tekutina, Reinerova-Philippova tekutina, pomalé prúdenie, prúdová funkcia, and odpor
- Language:
- Slovak
- Description:
- An analytical solution for the creeping flow of an inelastic fluid past a solid sphere has been obtained using an empirical 3-parameter fluid model. The governing equations of motion have been solved aproximately using a perturbation approach. Expressions have been obtained for the Stokes stream function and the drag experienced by the stationary sphere. It is shown that the drag for the non-Newtonian fluid is greater than the one predicted by the classical Stokes formula. and Použitím trojparametrického empirického modelu tekutiny sme získali analytické riešenie pomalého prúdenia neelastickej tekutiny okolo pevnej gule. Pohybové rovnice boli riešené približne metódou malých rozruchov. Získali sme vzťahy pre výpočet Stokesovej prúdovej funkcie a pre odpor stojacej gule. Bolo ukázané, že tento odpor z obtekania je pre nenewtonskú tekutinu väčší, ako vyplýva z klasického vzťahu Stokesa pre newtonskú tekutinu.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
570673. Steady laminar Couette flow of a dilatant fluid along a channel with suction at a bounding wall
- Creator:
- Sacheti, N.C., Chandran, P., Jaju, R.P., and Bhatt, B.S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- non-Newtonian fluid, plane Couette flow, similarity transformation, suction, skin friction, Nenewtonská tekutina, rovinné prúdenie Couette, transformácia podobnosti, sanie, and povrchové trenie
- Language:
- Slovak
- Description:
- We consider a special dilatant fluid model for which the apparent viscosity can be expressed as a polynomial in the second scalar invariant of the rate of strain tensor. The model has been used to investigate the steady plane Couette flow of a non-Newtonian fluid through a channel with suction, assumed small, at the lower porous wall. The introduction of a similarity transformation in the perturbed governing partial differential equations of the flow leads to a system of coupled non-linear ordinary differential equations. The solutions of these equations have been obtained analytically as a power series in the suction parameter . The combined effects of the non-Newtonian and the suction parameters on the longitudinal and transverse velocity profiles as well as the skin friction, have been discussed. The validity of the analytical solutions has also been checked with the corresponding numerical solutions for small values of the governing parameters. and Štúdia sa zaoberá sa špeciálnym modelom nenewtonskej tekutiny, pre ktorú sa môže skutočná viskozita vyjadriť vo forme polynomickej závislosti na druhom skalárnom invariante tenzora rýchlosti deformácie. Model bol využitý na štúdium ustáleného Couetteho rovinného prúdenia nenewtonskej tekutiny v kanáli so saním cez porézne steny. Zavedenie transformácie podobnosti do lineanizovaných parciálnych diferenciálnych rovníc vedie k systému obyčajných nelineárnych diferenciálnych rovníc. Ich riešenie sme získali vo forme potenčného radu od sacieho parametra λ. Analyzovali sme vplyv rozťažnosti tekutiny a sacieho parametra na pozdĺžny a priečny rýchlostny profil, ako aj na povrchové trenie. Platnosť analytického riešenia sme porovnali s numerickým riešením pre malé hodnoty použitých parametrov.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
570674. Steady state coexistence solutions of reaction-diffusion competition models
- Creator:
- Kang, Joon Hyuk and Lee, Jungho
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- elliptic theory and maximum principles
- Language:
- English
- Description:
- Two species of animals are competing in the same environment. Under what conditions do they coexist peacefully? Or under what conditions does either one of the two species become extinct, that is, is either one of the two species excluded by the other? It is natural to say that they can coexist peacefully if their rates of reproduction and self-limitation are relatively larger than those of competition rates. In other words, they can survive if they interact strongly among themselves and weakly with others. We investigate this phenomena in mathematical point of view. In this paper we concentrate on coexistence solutions of the competition model \[ \left\rbrace \begin{array}{ll}\Delta u + u(a - g(u,v)) = 0, \Delta v + v(d - h(u,v)) = 0& \text{in} \ \Omega , u|_{\partial \Omega } = v|_{\partial \Omega } = 0. \end{array}\right.\] This system is the general model for the steady state of a competitive interacting system. The techniques used in this paper are elliptic theory, super-sub solutions, maximum principles, implicit function theorem and spectrum estimates. The arguments also rely on some detailed properties of the solution of logistic equations.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
570675. Steady-state and induction kinetics of the photosynthetic electron transport related to donor side oxidation and acceptor side reduction of photosystem 1 in sunflower leaves
- Creator:
- Laisk, A., Oja, V., and Heber, U.
- Format:
- Type:
- model:internalpart and TEXT
- Language:
- Multiple languages
- Description:
- The photosynthetic CO2 exchange rate, chlorophyll fluorescence and P700 oxidation (absorption at 830 nm) were recorded in attached leaves of sunflower plants grown in soil by irradiance 460 pmol m'2 s‘i. Ehiring the photosynthesis in 510 cm^ m*3 CO2, 1 % O2, photosystem 1 (PS 1) effíciency was ahnost totally determined by the donor side oxidation under all irradiances. Fluorescence data showed that this control was exercised mostly by ApH-dependent plastoquinol oxidation. At 1.5 pM intracellular [CO2], the PS 1 reduction level on the acceptor side became signifícant and increased as [CO2] -> 0. ApH controlled the electron flow when the rate exceeded the value of 50 pmol(e‘) m'2 s‘i, which was close to the rate supporting photorespiration and CO2 reassimilation at CO2 compensation concentration in 21 % O2. The ApH ability to control the electron transport rate adequately prevented electron carriers reduction at PS 1 acceptor side, with stomata dosed under stress. When the low CO2 oř carbon reduction enzymes inactivation restricted the electron transport downstream of PS 1, open PS 1 centres (oxidised on acceptor sides) percentage declined in proportion to CO2 uptake rate. This makes us doubt the common belief that the rapid electron transport in photosynthesis involves interconnected, mobile electron carrier pools of plastocyanin and ferredoxin (Fd). Rather, the implications are explored in terms of supercomplexes involving cytochrome b(Jf, PC, PS 1, Fd and Fd-NADP reductase.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
570676. Steady-state buoyancy-driven viscous flow with measure data
- Creator:
- Roubíček, Tomáš
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- non-Newtonean fluids, heat equation, dissipative heat, and adiabatic heat
- Language:
- English
- Description:
- Steady-state system of equations for incompressible, possibly non-Newtonean of the p-power type, viscous flow coupled with the heat equation is considered in a smooth bounded domain Ω ⊂ ℝn, n = 2 or 3, with heat sources allowed to have a natural L1- structure and even to be measures. The existence of a distributional solution is shown by a fixed-point technique for sufficiently small data if p > 3/2 (for n = 2) or if p > 9/5 (for n = 3).
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
570677. Steady-state gadofosveset-enhanced dark lumen MR-enterography
- Creator:
- Ferda, Jiří
- Type:
- model:article and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
570678. Steatitovaja ikona "Neverie Formy" iz Krasena /
- Creator:
- Totev, Konstantin,
- Type:
- text and studie
- Subject:
- Malířství, Bulharsko, světové dějiny středověku (do r. 1492), and malířství, malíři
- Language:
- Russian
- Rights:
- unknown
570679. Steatotic rat hepatocytes in primary culture are more susceptible to the acute toxic effect of acetaminophen
- Creator:
- Otto Kučera, Al-Dury, S., Halka Lotková, Tomáš Roušar, Rychtrmoc, D., and Zuzana Červinková
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, fatty liver, acetaminophen, hepatocytes in vitro, hepatotoxicity, glutathione, 14, and 612
- Language:
- English
- Description:
- Acetaminophen (APAP) overdose is the most common cause of acute liver failure in humans. Non-alcoholic fatty liver disease is the most frequent chronic liver disease in developed countries. The aim of our work was to compare the effect of APAP on intact rat hepatocytes and hepatocytes isolated from steatotic liver in primary cultures. Male Wistar rats were fed with standard diet (10 % energy from fat) and high-fat diet (71 % energy from fat) for 6 weeks and then hepatocytes were isolated. After cell attachment, APAP (1; 2.5; 3.75 and 5 mM) was added to culture media (William´s E medium) and hepatocytes were cultured for up to 24 hours. APAP caused more severe dose-dependent damage of steatotic hepatocytes as documented by increased release of lactate dehydrogenase (LDH) and LDH leakage, decreased activity of cellular dehydrogenases (WST-1 test) and reduced albumin production. Intact steatotic hepatocytes contained lower amount of reduced glutathione (GSH). Treatment with APAP (1 and 2.5 mmol/l) caused more pronounced decrease in GSH in steatotic hepatocytes. ROS (reactive oxygen species) formation after 24-hour incubation was significantly higher in fatty hepatocytes using APAP at concentration of 3.75 and 5 mmol/l. Interleukin 6 (IL-6) production was elevated in 2.5 mM APAP-treated nonsteatotic and steatotic hepatocyte cultures at 8 hours, compared to appropriate controls. In conclusions, our results indicate that steatotic hepatocytes exert higher sensitivity to the toxic action of APAP. This sensitivity may be caused by lower content of GSH in intact steatotic hepatocytes and by more pronounced APAPinduced decrease in intracellular concentration of GSH., O. Kučera, ... [et al.]., and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
570680. Stébla
- Creator:
- PEKOVÁ, Věra
- Format:
- electronic
- Type:
- model:article and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public