scholarly journals The Effect of Heterogeneity on Large Scale Solute Transport in the Unsaturated Zone

1989 ◽  
Vol 20 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Georgia Destouni ◽  
Vladimir Cvetkovic
Keyword(s):  
Solute Transport ◽  
Random Fields ◽  
Unsaturated Zone ◽  
Large Scale ◽  
Control Flow ◽  
Stochastic Methods ◽  
Solute Flux ◽  
Physical Parameters ◽  
Conductivity Water ◽  
Simple Stochastic Model

The effect of natural heterogeneity on large scale solute transport in the unsaturated zone is investigated using stochastic methods. Several of the physical parameters that control flow and solute transport in the unsaturated zone are regarded as random fields. Specifically, the influence of spatial variability in recharge applied on the surface, saturated hydraulic conductivity, water content at saturation and depth to the groundwater table, on solute flux into the groundwater, is illustrated. It is shown that the prediction of solute penetration into the groundwater through the unsaturated zone is significantly affected by the natural variability in the physical parameters. A simple stochastic model for the estimation of large scale solute flux through the unsaturated zone, is provided.

scholarly journals Comparison of Some Physical Parameters of Whole and Scored Lisinopril and Lisinopril/Hydrochlorthiazide Tablets

2008 ◽  
Vol 8 (4) ◽  
pp. 391-395 ◽  
Author(s):  
Edina Vranić ◽  
Alija Uzunović
Keyword(s):  
Large Scale ◽  
Testing Procedure ◽  
Physical Parameters ◽  
Hardness Testing ◽  
Disintegration Time ◽  
Adequate Dose ◽  
Response Information ◽  
Tablet Splitting ◽  
Good Patient Compliance ◽  
Accepted Practice

Tablets are one of the most popular and preferred solid dosage forms because they can be accurately dosed, easily manufactured and packaged on a large scale, have good physical and chemical stability, and can contribute to good patient compliance given their ease of administration. The ability to match doses to patients depends on the availability of multiple dose sizes and adequate dose-response information. These are not always provided, so splitting of the tablets is sometimes necessary, Tablet splitting is an accepted practice in dispensing medication, It has been used when a dosage form of the required strength is not available commercially. The aim of our study was to compare some physical parameters of whole and scored lisinopril and lisinopril/hydrochlorthiazide tablets and to accept or exclude their influence on the obtaining of required dosage.According to the results obtained, we may conclude that tablets from batch “I” “IL “III” and “IV” satisfied pharmacopeial requirements concerning crushing strength, friability, disintegration time and mass uniformity. The hardness testing showed acceptable reproducibility and indicate that the data variation was primarily from the irreversible changes in the structure of tablet samples. The act of compacting powders stores energy within the tablets, by shifting or compressing the intermolecular bonds within the particles. The tablets have a natural tendency to relax once pressure is removed, and this tendency works against the interparticle bonding formed during compression. Hardness testing procedure causes irreversible changes in this structure.

Claudin Tight Junction Proteins: Novel Aspects in Paracellular Transport

2008 ◽  
Vol 28 (6) ◽  
pp. 577-584 ◽  
Author(s):  
Constanze Will ◽  
Michael Fromm ◽  
Dominik Müller
Keyword(s):  
Tight Junction ◽  
Solute Transport ◽  
Molecular Mechanisms ◽  
Family Members ◽  
Transport Processes ◽  
Paracellular Transport ◽  
Solute Flux ◽  
Solute Fluxes ◽  
Essential Components ◽  
Renal Tubular

Claudins are essential components of the intercellular tight junction and major determinants of paracellular solute fluxes across epithelia and endothelia. Many members of this family display a distinct charge or size specificity, whereas others render the epithelium impermeable to transport. Due to intercellular localization, claudin-mediated transport processes are passive and driven by an electrochemical gradient. In epithelial tissues, claudins exhibit a temporal–spatial expression pattern corresponding with regional and local solute transport profiles. Whereas paracellular transport mechanisms in organs such as intestine and kidney have been extensively investigated, little is known about the molecular mechanisms determining solute transport in the peritoneum, and thus the determinants of peritoneal dialysis. Given the ubiquitous expression of claudins in endothelia and epithelia, it is predictable that claudins also contribute to pore formation and determination in the peritoneum, and that they are involved in solute flux. Therefore, we review the basic characteristics of claudin family members and their function as exemplified in renal tubular transport and give an outlook to what extent claudin family members might be of importance for solute reabsorption across the peritoneal membrane.

scholarly journals Groundwater age, brine migration, and large-scale solute transport in the Alberta Basin, Canada

Geofluids ◽  
2015 ◽  
Vol 15 (4) ◽  
pp. 608-620 ◽  
Author(s):  
I. Gupta ◽  
A. M. Wilson ◽  
B. J. Rostron
Keyword(s):  
Solute Transport ◽  
Large Scale ◽  
Groundwater Age ◽  
Brine Migration ◽  
Alberta Basin

scholarly journals Scaling of separated shear layers: an investigation of mass entrainment

2017 ◽  
Vol 826 ◽  
pp. 851-887 ◽  
Author(s):  
Francesco Stella ◽  
Nicolas Mazellier ◽  
Azeddine Kourta
Keyword(s):  
Shear Layer ◽  
Large Scale ◽  
Separated Flow ◽  
Layer Growth ◽  
Upper And Lower Bounds ◽  
Stream Velocity ◽  
Physical Parameters ◽  
Separated Shear Layer ◽  
Mass Entrainment ◽  
Recirculation Length

We report an experimental investigation of the separating/reattaching flow over a descending ramp with a $25^{\circ }$ expansion angle. Emphasis is given to mass entrainment through the boundaries of the separated shear layer emanating from the upper edge of the ramp. For this purpose, the turbulent/non-turbulent interface and the separation line inferred from image-based analysis are used respectively to mark the upper and lower bounds of the separated shear layer. The main objective of this study is to identify the physical parameters that scale the development of the separated shear layer, by giving a specific emphasis to the investigation of mass entrainment. Our results emphasise the multiscale nature of mass entrainment through the separated shear layer. The recirculation length $L_{R}$, step height $h$ and free-stream velocity $U_{\infty }$ are the dominant scales that organise the separated flow (and related large-scale quantities as pressure distribution or shear layer growth rate) and set mean mass fluxes. However, local viscous mechanisms seem to be responsible for most of local mass entrainment. Furthermore, it is shown that large-scale mass entrainment is driven by incoming boundary layer properties, since $L_{R}$ scales with $Re_{\unicode[STIX]{x1D703}}$, and in particular by its turbulent state. Surprisingly, the relationships evidenced in this study suggest that these dependencies are established over a large distance upstream of separation and that they might also extend to small scales, at which viscous entrainment is dominant. If confirmed by additional studies, our findings would open new perspectives for designing effective separation control systems.

scholarly journals Large-Scale Buildings of the Resort Establishments of the Soviet Period and their Present State in Jūrmala City, Latvia

2021 ◽  
Vol 17 (1) ◽  
pp. 29-45
Author(s):  
Baiba Vērpe
Keyword(s):  
Present State ◽  
Physical Condition ◽  
Large Scale ◽  
Soviet Period ◽  
Physical Parameters

Abstract The paper presents a summary of large-scale buildings of resort establishments of Soviet period in Jūrmala, by analysing their typology, physical parameters, scenarios of the development, architectural stylistic and the present state of physical condition and authentic substance. The research reveals that half of the large-scale resort buildings are already irreversibly lost and the rest of buildings are seriously endangered due to the tendency of extensive rebuilding.

scholarly journals Analysis of Groundwater Quality in Jabal Sarage and Charikar Districts, Parwan, Afghanistan

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Hafizullah Rasouli
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Dissolved Oxygen ◽  
Groundwater Quality ◽  
Water Temperature ◽  
Toxic Elements ◽  
Physical Parameters ◽  
Drinking And Irrigation ◽  
Conductivity Water ◽  
Irrigation Waters

This groundwater research is carried out groundwater quality in Jabal Sarage and Charikar Districts. The main objective of this research is to find out natural causes of drinking water contaminations (toxic elements and components), that are leaching from soluble arrangement of rocks,sediments and soil by surface water at the infiltration time, toward the groundwater. For completion this research I used two categories of water analysis; one is areal analysis, and another is laboratory analysis. In areal analysis ten wells have been recovered by this research in Jabal Sarage and Charikar Distracts, a number of Electro-Conductivity, water temperature,dissolved oxygen in water, Total Dissolved Soled (TDS) and the Resolved Salt in Water (SSW), determination Partible ground at areal complete. For laboratory works I used chemical device of Spectra- photo model. From comparing mean of chemical and physical parameters with standards.pH, K, Na, Mg, Cl, Fe, F, TH, Ca and SO4 all are normal and we can use them for drinking and irrigation waters. The challenges that I faced during this research are; absence of research in this area and lack of geological equipment’s.

Power spectral density of magnetic field and ion velocity fluctuations from inertial to kinetic ranges

2021 ◽  
Author(s):  
Jana Šafránková ◽  
Zdeněk Němeček ◽  
František Němec ◽  
Luca Franci ◽  
Alexander Pitňa
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Large Scale ◽  
Collisionless Plasma ◽  
Power Spectra ◽  
Physical Parameters ◽  
Particle In Cell ◽  
High Reynolds ◽  
Experimental Findings ◽  
Turbulent Cascade

<p>The solar wind is a unique laboratory to study the turbulent processes occurring in a collisionless plasma with high Reynolds numbers. A turbulent cascade—the process that transfers the free energy contained within the large scale fluctuations into the smaller ones—is believed to be one of the most important mechanisms responsible for heating of the solar corona and solar wind. The paper analyzes power spectra of solar wind velocity, density and magnetic field fluctuations that are computed in the frequency range around the break between inertial and kinetic scales. The study uses measurements of the Bright Monitor of the Solar Wind (BMSW) on board the Spektr-R spacecraft with a time resolution of 32 ms complemented with 10 Hz magnetic field observations from the Wind spacecraft propagated to the Spektr-R location. The statistics based on more than 42,000 individual spectra show that: (1) the spectra of both quantities can be fitted by two (three in the case of the density) power-law segments; (2) the median slopes of parallel and perpendicular fluctuation velocity and magnetic field components are different; (3) the break between MHD and kinetic scales as well as the slopes are mainly controlled by the ion beta parameter. These experimental results are compared with high-resolution 2D hybrid particle-in-cell simulations, where the electrons are considered to be a massless, charge-neutralizing fluid with a constant temperature, whereas the ions are described as macroparticles representing portions of their distribution function. In spite of several limitations (lack of the electron kinetics, lower dimensionality), the model results agree well with the experimental findings. Finally, we discuss differences between observations and simulations in relation to the role of important physical parameters in determining the properties of the turbulent cascade.</p>

Rapid Development of Adaptable Situation-Aware Service-based Systems

2010 ◽  
pp. 104-139 ◽  
Author(s):  
S.S. Yau ◽  
S. Mukhopadhyay ◽  
H. Davulcu ◽  
D. Huang ◽  
R. Bharadwaj ◽  
...  
Keyword(s):  
Distributed Control ◽  
Homeland Security ◽  
Situation Awareness ◽  
Service Composition ◽  
Large Scale ◽  
Rapid Development ◽  
Control Flow ◽  
Agent Platform ◽  
Service Oriented ◽  
Adaptive Workflows

Service-based systems have many applications, such as collaborative research and development, e-business, health care, military applications and homeland security. In these systems, it is necessary to provide users the capability of composing appropriate services into workflows offering higher-level functionality based on declaratively specified goals. In a large-scale and dynamic service-oriented computing environment, it is desirable that the service composition is automated and situation-aware so that robust and adaptive workflows can be generated. However, existing languages for web services are not expressive enough to model services with situation awareness (SAW) and side effects. This chapter presents an approach to rapid development of adaptable situation-aware service-based systems. This approach is based on the a-logic and a-calculus, and a declarative model for SAW. This approach consists of four major components: (1) analyzing SAW requirements using our declarative model for SAW, (2) translating the model representation to a-logic specifications and specifying a control flow graph in a-logic as the goal for situation-aware service composition., (3) automated synthesis of a-calculus terms that define situation-aware workflow agents for situation-aware service composition, and (4) compilation of a-calculus terms to executable components on an agent platform. An example of applying our framework in developing a distributed control system for intelligently and reliably managing a power grid is given.

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