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51.
Considering the htermal conduction through molecular collisions an expression for the effective thermal conductivityλ
e
of loose and granular two-phase materials at different interstitial air pressure has been derived. The dependence ofλ
e
on pore and particle sizes, characteristic pressure and radiative heat transfer is also discussed. Calculated values ofλ
e
of glass beads and loose building materials are compared with reported results. 相似文献
52.
The problem of temperature distribution and heat transfer for laminar flow through two parallel porous disks of different
permeability, has been investigated when the flow is entirely due to injection and/or suction at the two disks. Viscous dissipation
terms have been included in the energy equation and the injection and/or suction velocities at the two disks are assumed to
be small. The boundaries are kept at constant temperatures. The variation of temperature and Nusselt numbers at the two disks
has been graphically depicted for various values of the injection and suction velocities. 相似文献
53.
Shukla R Bansal V Chaudhary M Basu A Bhonde RR Sastry M 《Langmuir : the ACS journal of surfaces and colloids》2005,21(23):10644-10654
Macrophages are one of the principal immune effector cells that play essential roles as secretory, phagocytic, and antigen-presenting cells in the immune system. In this study, we address the issue of cytotoxicity and immunogenic effects of gold nanoparticles on RAW264.7 macrophage cells. The cytotoxicity of gold nanoparticles has been correlated with a detailed study of their endocytotic uptake using various microscopy tools such as atomic force microscopy (AFM), confocal-laser-scanning microscopy (CFLSM), and transmission electron microscopy (TEM). Our findings suggest that Au(0) nanoparticles are not cytotoxic, reduce the production of reactive oxygen and nitrite species, and do not elicit secretion of proinflammatory cytokines TNF-alpha and IL1-beta, making them suitable candidates for nanomedicine. AFM measurements suggest that gold nanoparticles are internalized inside the cell via a mechanism involving pinocytosis, while CFLSM and TEM studies indicate their internalization in lysosomal bodies arranged in perinuclear fashion. Our studies thus underline the noncytotoxic, nonimmunogenic, and biocompatible properties of gold nanoparticles with the potential for application in nanoimmunology, nanomedicine, and nanobiotechnology. 相似文献
54.
The weighted geometric mean of resistors considered for determining the effective thermal conductivityK E of two-phase systems has been optimised. Solutions of the equations lead to a useful set of bounds. When compared with other bounds the present bounds give the better results in estimating the upper and lower values of the effective thermal conductivity of a two-phase system. 相似文献
55.
S. Ahmad M. S. Chaudhary I. H. Qureshi 《Journal of Radioanalytical and Nuclear Chemistry》1980,57(1):185-193
An instrumental neutron activation analysis technique has been developed for simultaneous determination of 10 REE in low grade U/Zr ores and other geological materials. The samples were irradiated with reactor neutrons for 2 min to 8 hrs followed by a cooling of 30 min to 3 weeks. The γ-ray activity was measured with a semi-planar Ge(Li) detector. A precision of 5% has been obtained by the repeated analysis of NBS-SRM. The technique is relatively simple and adaptable on the routine basis. 相似文献
56.
Reshma Khemchandani Nishil Gupta Arpit Chaudhary Suresh Chandra 《Optimization Letters》2013,7(3):575-592
In this paper, we develop optimal trading strategies for a risk averse investor by minimizing the expected cost and the risk of execution. Here we consider a law of motion for price which uses a convex combination of temporary and permanent market impact. In the special case of unconstrained problem for a risk neutral investor, we obtain a closed form solution for optimal trading strategies by using dynamic programming. For a general problem, we use a quadratic programming approach to get approximate dynamic optimal trading strategies. Further, numerical examples of optimal execution strategies are provided for illustration purposes. 相似文献
57.
Sudhakar Chaudhary V.V.K. Srinivas Kumar 《Numerical Methods for Partial Differential Equations》2013,29(4):1322-1340
In this article, we give some numerical techniques and error estimates using web‐spline based mesh‐free finite element method for the heat equation and the time‐dependent Navier–Stokes equations on bounded domains. The web‐spline method uses weighted extended B‐splines on a regular grid as basis functions and does not require any grid generation. We demonstrate the method by providing numerical results for the Poisson's and stationary Stokes equation. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013 相似文献
58.
Sudhakar Chaudhary V. V. K. Srinivas Kumar 《Numerical Functional Analysis & Optimization》2013,34(3):264-283
The objective of this article is to discuss the existence and the uniqueness of a weighted extended B-spline-(WEB-spline) based discrete solution for the Maxwell equations in low frequency limit. The domain is composed of insulating and conducting regions. This problem has saddle point structure where the electric field in insulating region is the Lagrange multiplier that forces curl-free constraint on the magnetic field. 相似文献
59.
M. A.?Naveed N. U.?Rehman S.?Zeb S.?Hussain M.?ZakaullahEmail author 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(3):395-402
This paper reports the effect of helium percentage variation in a capacitive RF helium-nitrogen mixture plasma on various
plasma parameters and concentration of nitrogen active species (N2(C3Π u) and N2
+(B2Σ u
+)). Langmuir probe is used for determination of electron energy distribution functions, effective electron temperature, plasma
potential and electron density. Optical emission spectroscopy is used for determination of electron temperature from Boltzmann's
plot of He–I lines and the relative changes in the concentration of active species by measuring the emission intensities of
nitrogen (0-0) bands of the second positive and the first negative systems. The results demonstrate that electron temperature,
electron density and concentration of active species increase significantly with increase in helium percentage in the mixture
and RF power. 相似文献
60.
Mehwish Nawaz Haji Muhammad Shoaib Khan Naveed Akhtar Talha Jamshed Rubina Qaiser Hina Shoukat Mehrin Farooq 《Photochemistry and photobiology》2019,95(5):1243-1248
Solar radiations trigger the physiological alteration in skin which progress toward photoaging. Sunscreens are known to be effective against the photodamaging effects of sunlight. The purpose of this study was to evaluate the extent to which aging signs caused by real‐life sunlight exposure could be avoided by comparing various parameters between sun‐exposed and sun‐protected skin using noninvasive probes. Female volunteers (n = 11) after getting their consent were provided with marketed sunscreen product to apply onto their skin for 6 months. Measurements were scheduled every 15 days from the baseline reading for 6 months. Cutometer, Mexameter and Corneometer were used for evaluation of facial skin parameters. Clinical evaluations showed the effects of sunlight exposure on different skin parameters by comparing sun‐protected and unprotected skin, where Gross elasticity (R2), Net elasticity (R5), Viscoelasticity (R6) and Biological elasticity (R7) showed insignificant results, while Hydration, Melanin and Erythema showed significant results. Sun‐exposed skin presented 0.72%, 0.66%, 0.77%, 1.39%, 1.99%, 2.01% and 3.15% changes in R2, R5, R6 and R7, melanin, erythema and hydration, respectively, which were potentially prevented by sunscreen application. Premature aging is inhibited by following photoprotective regimen on routine basis, emphasizing the potential benefit of sunscreen against early aging signs. 相似文献