Dispersion of oil spilled under solid ice cover

2014 ◽  
Vol 11 (5) ◽  
pp. 495-506
Author(s):  
Nirmala Ratchagar ◽  
S. Hemalatha
Keyword(s):  
Particle Concentration ◽  
Dispersion Model ◽  
Perturbation Technique ◽  
Ice Cover ◽  
Axial Distance ◽  
Dimensionless Time ◽  
Pure Solvent ◽  
The Mean ◽  
Mean Concentration ◽  
Generalized Dispersion Model

The model, presented here, is developed to study the axial dispersion and distribution of oil particle concentration in the presence of coriolis force of oil spilled under solid ice cover. The movement of oil slick is obtained by employing perturbation technique and the dispersion of oil is studied using generalized dispersion model proposed by Gill (1967). The mean concentration is computed by introducing a slug of finite length separated from pure solvent using suitable impermeable barriers by varying the dimensionless time, axial distance and length of solute slug. The results obtained are discussed in detail with the help of graphs and tables.

Effect of couple stress and magnetic field on the unsteady convective diffusion in blood flow

2014 ◽  
Vol 11 (4) ◽  
pp. 403-412 ◽  
Author(s):  
Nirmala Ratchagar ◽  
R. Kumar
Keyword(s):  
Magnetic Field ◽  
Couple Stress ◽  
Dispersion Coefficient ◽  
Convective Diffusion ◽  
Dispersion Model ◽  
Artificial Organs ◽  
Axial Distance ◽  
The Mean ◽  
The Magnetic Field ◽  
Mean Concentration

The effect of magnetic field on unsteady convective diffusion in a couple stress fluid (blood) is studied using a time dependent dispersion model. This model is used to calculate the mean concentration distribution of a solute, bounded by the porous layer and is expressed as a function of dimensionless axial distance and time. The magnetic field, arising as a body couple in the governing equations is shown to increase the axis dispersion coefficient. This is useful to the control of haemolysis caused by artificial organs implanted or extracorporeal. Dispersion coefficient and mean concentration are computed for different values of Hartmann number (M), Couple Stress Parameter (a) and Porous Parameter (σ).

Observations of dispersion of entrained fluid in the self-preserving region of a turbulent jet

1987 ◽  
Vol 183 ◽  
pp. 163-173 ◽  
Author(s):  
D. Joseph Shlien
Keyword(s):  
Large Scale ◽  
Peak Velocity ◽  
Turbulent Jet ◽  
Axial Distance ◽  
Large Scale Structures ◽  
Jet Nozzle ◽  
The Mean ◽  
Scale Structures ◽  
Processing Techniques ◽  
Mean Concentration

Ambient fluid of a submerged water jet was continuously tagged with fluorescent dye at a point outside the turbulent region (at 33 jet nozzle diameters from the jet exit). This made it possible to follow the tagged entrained fluid to 73 jet diameters downstream of the exit, a distance unattainable by other methods. The dispersion of the tagged fluid in a plane containing the jet axis and the tagging source was observed and recorded using photography and simple digital image-processing techniques. Most of the entrainment activity appeared to be the result of engulfment by the large-scale structures over an axial distance of ± 1.7B from the source where B is the half-peak velocity radius. The entrained fluid crossed the jet centreline within a downstream distance of Δx = 1.5B.Downstream of the entrainment region, the spread rate of the tagged entrained fluid was close to that of the turbulent jet fluid. However, the peak mean concentration of the tagged entrained fluid was located near the r/x = 0.1 line closest to the tagging source and shifted very slowly towards the jet centreline. A self-preserving distribution of the mean concentration appears to have been approached after a distance of 6B downstream from the tagging source but further verification is needed owing to experimental uncertainties.A small fraction of the tagged entrained fluid was found on the side of the jet remote from the tagging source. On rare occurrences, tagged entrained fluid was observed at the interface most remote from the source.

Study on the Mean Value of Particle Concentration Signal in Silicon Power Fluidized Bed

2012 ◽  
Vol 550-553 ◽  
pp. 2936-2940
Author(s):  
Xing Yong Liu ◽  
Hu Yang ◽  
You Cheng Wang ◽  
Zhuo Xu Deng
Keyword(s):  
Neural Network ◽  
Fluidized Bed ◽  
Particle Concentration ◽  
Rbf Neural Network ◽  
Radial Distance ◽  
Mean Value ◽  
Operating Conditions ◽  
Axial Distance ◽  
The Mean ◽  
Concentration Signal

The particle concentration signals of silicon powder in the fluidizing gas i.e. air under different operating conditions were determined. The diameter of silicon particles, operating velocity, radial distance and axial distance are used as input vector; the mean value of particle concentration signal in the silicon power fluidized bed is used as a target vector. The RBF neural network is applied to build the predicted model of the mean value in silicon power fluidized bed. The result shows that the prediction of mean value through the RBF neural network is prior to that by BP neural network, and its error is less than 0.2%.

Dispersion in Laminar Flow Through Tubes by Simultaneous Diffusion and Convection

1981 ◽  
Vol 48 (2) ◽  
pp. 217-223 ◽  
Author(s):  
J. S. Yu
Keyword(s):  
Laminar Flow ◽  
Molecular Diffusion ◽  
Solute Concentration ◽  
Dimensionless Time ◽  
Mean Flow ◽  
Round Tube ◽  
Flow Through ◽  
The Mean ◽  
Time Required ◽  
Mean Concentration

The dispersion of a small quantity of a solute initially injected into a round tube in which steady-state laminar flow exists is critically examined. It is shown that the mean solute concentration profile is far from being symmetric at small dimensionless times after injection. The mean concentration and the axial location at the peak of the profile are presented in detail as functions of time for flow with various Peclet numbers. It is suggested that such results may be useful for determining either the molecular diffusion coefficient or the mean flow velocity or both from experimental measurements. A previously established criterion in terms of the Peclet number for determining the minimum dimensionless time required for applying Taylor’s theory of dispersion is graphically illustrated. Although the complete generalized dispersion equation of Gill’s model is exact, the truncated two-term form of it with time-dependent coefficients is exact only asymptotically at large values of time; however, at small Peclet numbers, the two-term approximation is shown graphically to be reasonably satisfactory over all values of time. The exact series solution is compared with the solution of Tseng and Besant through the use of Fourier transform.

Study of Two-Dimensional, all – Time Dispersion of a Solute in a Fluid – Saturated Porous Medium

2017 ◽  
Vol 13 (3) ◽  
pp. 67-85
Author(s):  
Pranesh S
Keyword(s):  
Porous Medium ◽  
Dispersion Coefficient ◽  
Dispersion Model ◽  
Saturated Porous Medium ◽  
Mathematical Formulation ◽  
Unidirectional Flow ◽  
Time Dispersion ◽  
Flow Through ◽  
Mean Concentration ◽  
Generalized Dispersion Model

The paper presents the mathematical formulation which describes the dispersion of solute in a laminar flow in a sparsely packed porous medium. The effect of interphase mass transfer on dispersion in a unidirectional flow through a horizontally extent of infinite porous channel is examined using the generalized dispersion model of Sankarasubramanian and Gill. The model brings into focus three important coefficients namely the exchange coefficient, the convection coefficient and the dispersion coefficient. The time-dependent dispersion coefficient and mean concentration distribution are computed and results are represented graphically. The problem finds many applications in waste water management, in chromatography and in biomechanical problems.

Instabilities of fully developed rapid flow of a granular material in a channel

1997 ◽  
Vol 342 ◽  
pp. 179-197 ◽  
Author(s):  
CHI-HWA WANG ◽  
R. JACKSON ◽  
S. SUNDARESAN
Keyword(s):  
Granular Material ◽  
Particle Concentration ◽  
Travelling Waves ◽  
Equations Of Motion ◽  
Axial Direction ◽  
Small Perturbations ◽  
Rapid Flow ◽  
The Mean ◽  
The Stability ◽  
Mean Concentration

The equations of motion for ‘rapid’ flow of a granular material have fully developed solutions representing flow driven by a body force, such as gravity, along a channel bounded by plane parallel walls. The stability of these solutions to small perturbations is investigated. For given properties of the particles and the channel walls it is found that the condition of critical stability is a relation between the mean concentration of the particles and the width of the channel. When the base state is unstable the fastest growing modes are travelling waves propagating in the axial direction and these induce characteristic patterns of variations in particle concentration, as well as velocity. These instabilities are contrasted with those found for Couette shearing in an earlier publication.

Instant 99mTc-Labelled Glucoheptonate Kit for Kidney Imaging

1983 ◽  
Vol 22 (05) ◽  
pp. 246-250 ◽  
Author(s):  
M. Al-Hilli ◽  
H. M. A. Karim ◽  
M. H. S. Al-Hissoni ◽  
M. N. Jassim ◽  
N. H. Agha
Keyword(s):  
Sodium Hydroxide Solution ◽  
Normal Subjects ◽  
Organ Distribution ◽  
Stable Complex ◽  
Scintillation Camera ◽  
Ph Adjustment ◽  
The Mean ◽  
The Stability ◽  
Kidney Imaging ◽  
Mean Concentration

Gelchromatography column scanning has been used to study the fractions of reduced hydrolyzed 99mTc, 99mTc-pertechnetate and 99mTc-chelate in a 99mTc-glucoheptonate (GH) preparation. A stable high labelling yield of 99mTc-GH complex in the radiopharmaceutical has been obtained with a concentration of 40-50 mg of glucoheptonic acid-calcium salt and not less than 0.45 mg of SnCl2 2 H2O at an optimal pH between 6.5 and 7.0. The stability of the complex has been found significantly affected when sodium hydroxide solution was used for the pH adjustment. However, an alternative procedure for final pH adjustment of the preparation has been investigated providing a stable complex for the usual period of time prior to the injection. The organ distribution and the blood clearance data of 99mTc-GH in rabbits were relatively similar to those reported earlier. The mean concentration of the radiopharmaceutical in both kidneys has been studied in normal subjects for one hour with a scintillation camera and the results were satisfactory.

PROGESTERONE IN THE HUMAN PERIPHERAL BLOOD IN THE PREOVULATORY PERIOD OF THE MENSTRUAL CYCLE

1967 ◽  
Vol 55 (1) ◽  
pp. 91-96 ◽  
Author(s):  
Benno Runnebaum ◽  
Josef Zander
Keyword(s):  
Menstrual Cycle ◽  
Corpus Luteum ◽  
Peripheral Blood ◽  
Human Peripheral Blood ◽  
Progesterone Concentration ◽  
Plasma Progesterone ◽  
Progesterone Secretion ◽  
Graafian Follicle ◽  
The Mean ◽  
Mean Concentration

ABSTRACT Progesterone was determined and identified in human peripheral blood during the preovulatory period of the menstrual cycle, by combined isotope derivative and recrystallization analysis. The mean concentration of progesterone in 1.095 ml of plasma obtained 9 days before ovulation was 0.084 μg/100 ml. However, the mean concentration of progesterone in 1.122 ml of plasma obtained 4 days before ovulation was 0.279 μg/100 ml. These data demonstrate a source of progesterone secretion other than the corpus luteum. The higher plasma-progesterone concentration 4 days before ovulation may indicate progesterone secretion of the ripening Graafian follicle of the ovary.

scholarly journals The Relationship between Inflammation Markers (CRP, IL-6, sCD40L) and Colorectal Cancer Stage, Grade, Size and Location

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1382
Author(s):  
Olga Martyna Koper-Lenkiewicz ◽  
Violetta Dymicka-Piekarska ◽  
Anna Justyna Milewska ◽  
Justyna Zińczuk ◽  
Joanna Kamińska
Keyword(s):  
Colorectal Cancer ◽  
Linear Regression ◽  
Tumor Size ◽  
Distal Colon ◽  
Proximal Colon ◽  
Model Parameters ◽  
Grade Group ◽  
Who Grade ◽  
The Mean ◽  
Mean Concentration

The aim of the study was the evaluation whether in primary colorectal cancer (CRC) patients (n = 55): age, sex, TNM classification results, WHO grade, tumor location (proximal colon, distal colon, rectum), tumor size, platelet count (PLT), mean platelet volume (MPV), mean platelet component (MCP), levels of carcinoembryonic antigen (CEA), cancer antigen (CA 19-9), as well as soluble lectin adhesion molecules (L-, E-, and P-selectins) may influence circulating inflammatory biomarkers: IL-6, CRP, and sCD40L. We found that CRP concentration evaluation in routine clinical practice may have an advantage as a prognostic biomarker in CRC patients, as this protein the most comprehensively reflects clinicopathological features of the tumor. Univariate linear regression analysis revealed that in CRC patients: (1) with an increase in PLT by 10 × 103/μL, the mean concentration of CRP increases by 3.4%; (2) with an increase in CA 19-9 of 1 U/mL, the mean concentration of CRP increases by 0.7%; (3) with the WHO 2 grade, the mean CRP concentration increases 3.631 times relative to the WHO 1 grade group; (4) with the WHO 3 grade, the mean CRP concentration increases by 4.916 times relative to the WHO 1 grade group; (5) with metastases (T1-4N+M+) the mean CRP concentration increases 4.183 times compared to non-metastatic patients (T1-4N0M0); (6) with a tumor located in the proximal colon, the mean concentration of CRP increases 2.175 times compared to a tumor located in the distal colon; (7) in patients with tumor size > 3 cm, the CRP concentration is about 2 times higher than in patients with tumor size ≤ 3 cm. In the multivariate linear regression model, the variables that influence the mean CRP value in CRC patients included: WHO grade and tumor localization. R2 for the created model equals 0.50, which indicates that this model explains 50% of the variance in the dependent variable. In CRC subjects: (1) with the WHO 2 grade, the mean CRP concentration rises 3.924 times relative to the WHO 1 grade; (2) with the WHO 3 grade, the mean CRP concentration increases 4.721 times in relation to the WHO 1 grade; (3) with a tumor located in the rectum, the mean CRP concentration rises 2.139 times compared to a tumor located in the distal colon; (4) with a tumor located in the proximal colon, the mean concentration of CRP increases 1.998 times compared to the tumor located in the distal colon; if other model parameters are fixed.

Sign in / Sign up

Export Citation Format

Share Document