Search results for " solution"
showing 10 items of 3084 documents
Practical formula for the evaluation of high-order multiphoton absorption in thin nonlinear media
2009
We present an analytical formula for the fast and accurate evaluation of nonlinear absorption in materials exhibiting an admixture of different multiphoton processes. This approach is specifically addressed for its use in thin films when the slowly varying envelope approximation applies. The contribution of absorptions of distinct order is conveniently averaged in order to use well-known expressions for a single multiphoton process. In the latter case, therefore, our simple expression is reduced toward the exact solution.
SNAT2 silencing prevents the osmotic induction of transport system A and hinders cell recovery from hypertonic stress.
2005
AbstractUnder hypertonic conditions the induction of SLC38A2/SNAT2 leads to the stimulation of transport system A and to the increase in the cell content of amino acids. In hypertonically stressed human fibroblasts transfection with two siRNAs for SNAT2 suppressed the increase in SNAT2 mRNA and the stimulation of system A transport activity. Under the same condition, the expansion of the intracellular amino acid pool was significantly lowered and cell volume recovery markedly delayed. It is concluded that the up-regulation of SNAT2 is essential for the rapid restoration of cell volume after hypertonic stress.
ENTROPY SOLUTIONS IN THE STUDY OF ANTIPLANE SHEAR DEFORMATIONS FOR ELASTIC SOLIDS
2000
The concept of entropy solution was recently introduced in the study of Dirichlet problems for elliptic equations and extended for parabolic equations with nonlinear boundary conditions. The aim of this paper is to use the method of entropy solutions in the study of a new problem which arise in the theory of elasticity. More precisely, we consider here the infinitesimal antiplane shear deformation of a cylindrical elastic body subjected to given forces and in a frictional contact with a rigid foundation. The elastic constitutive law is physically nonlinear and the friction is described by a static law. We present a variational formulation of the model and prove the existence and the uniquen…
De Giorgi–Nash–Moser Theory
2015
We consider the second-order, linear, elliptic equations with divergence structure $$\mathrm{div} (\mathbb{A}(x)\nabla u(x))\;=\;\sum\limits^n_{i,j=1}\;\partial_{x_{i}}(a_{ij}(x)\partial_{x_{j}}u(x))\;=\;0.$$
Lithographic fabrication of soda-lime glass based microfluidics
2013
Abstract Glass is an important material for chemical processing and analysis because of its relatively low cost, mechanical strength, chemical inertness, optical transparency, and electrical insulation and temperature resistance far beyond that of most polymeric materials. We have investigated techniques for direct writing with MeV ions on soda-lime glass as well as capping procedures to form closed buried channels suitable for high-pressure driven flow. Exposure and development of open-channel structures was studied using a combination of programmable proximity aperture lithography and different developers. Unlike our previous work on MeV ion beam lithography of natural silica where an 8% …
Physiological HEPES Buffer Proposed as a Calibrator for pH Measurement in Human Blood
1999
Abstract N-(2-hydroxyethyl)-piperazine-N'-2-ethanesulfonic acid, known as HEPES buffer, with p K in the physiological range was studied for use as an alternative to conventional phosphate buffer for the calibration of pH in modern clinical analyzers. In different series of aqueous equimolar HEPES buffer, pH was measured at 37 °C with a capillary glass electrode standardized previously using phosphate, and variations due to changes in total HEPES buffer concentration (0.025 to 0.320 mol/l), and NaCl (0 to 0.250 mol/l) were monitored. For 0.05 equimolar HEPES buffer without NaCl, the pH of 7.362 ± 0.003 (n = 15) obtained coincided well with the reference pH (7.364) from the National Institute…
Comparison of adsorption equilibrium models and error functions for the study of sulfate removal by calcium hydroxyapatite microfibrillated cellulose…
2017
In the present study, the adsorption of sulfates of sodium sulfate (Na2SO4) and sodium lauryl sulfate (SLS) by calcium hydroxyapatite-modified microfibrillated cellulose was studied in the aqueous solution. The adsorbent was characterized using elemental analysis, Fourier transform infrared, scanning electron microscope and elemental analysis in order to gain the information on its structure and physico-chemical properties. The adsorption studies were conducted in batch mode. The effects of solution pH, contact time, the initial concentration of sulfate and the effect of competing anions were studied on the performance of synthesized adsorbent for sulfate removal. Adsorption kinetics indica…
Saturation excess runoff numerical simulation
2005
Saturation excess runoff is a relevant process which needs additional experimental and modeling efforts. This work is focused on its numerical modeling. The final objective is the successive interpretation of ongoing experimental monitoring results in two watersheds in different areas of Italy where the saturation excess runoff formation mechanism seems to be important. The numerical solution of the two-dimensional Richards’ equation allows the evaluation of the sensitivity to the various influent parameters : rainfall intensity, soil properties, depth and initial water content, slope and hillslope length. Also the subsurface flow is simulated at the same time, allowing the evaluation of th…
Different Type Clay Amendments for Lead Immobilization in Contaminated Soils
2014
Contamination with lead in soil is a crucial problem in industrial and military sites. Immobilization of lead by natural and modified clay as soil amendment can be an effective solution to this problem. Quaternary and Devonian clays were chosen for modification with NaCl, CaCl2, FeOOH and Ca10(PO4)6(OH)2 in different proportions of Ca/P equimolar ratio to test and compare immobilization efficiency of lead (II) on raw and modified clays by using a batch leaching test. The aim of the study is to compare different types of raw and modified clays as soil amendments by lead immobilization properties.
Modeling the acid-base properties of molybdate(VI) in different ionic media, ionic strengths and temperatures, by EDH, SIT and Pitzer equations
2017
This paper reports the results of a study on the determination of the protonation constants of MoO42 −, in NaClaq, NaNO3aq, KClaq, at different ionic strengths (0 < I/mol dm− 3 ≤ 5.0 in NaClaq, 0 < I/mol dm− 3 ≤ 3.0 in NaNO3aq and KClaq) and temperatures (278.15 ≤ T/K ≤ 318.15 in NaClaq, only 298.15 K in NaNO3aq and KClaq), by potentiometric (ISE-H+ glass electrode) and spectrophotometric (UV/Vis) titrations. After a critical analysis of results and literature findings, the proposed speciation model takes into account the formation of two monomeric and four heptameric species, namely: MoO4H−, MoO4H2, (MoO4)7H86 −, (MoO4)7H95 −, (MoO4)7H104 − and (MoO4)7H113 −. Due to the complexity of…