Determination of 137Cs and 85Sr transport parameters in fucoidic sand columns and groundwater system

AbstractThe determination is based on the evaluation of experimentally obtained breakthrough curves using the erfc-function. The first method is founded on the assumption of a reversible linear sorption/desorption isotherm of radionuclides on solid phase with constant distribution and retardation coefficients, whereas the second one is based on the assumption of a reversible non-linear sorption/desorption isotherm described with the Freundlich equation, i.e., with non-constant distribution and retardation coefficients. Undisturbed cores of 5 cm in diameter and 10 cm long were embedded in the Eprosin-type cured epoxide resin column. In this study the so-called Cenomanian background groundwater was used as transport medium. The groundwater containing radionuclides was introduced at the bottom of the columns at about 4 mL h−1 constant flow-rate. The results have shown that in the investigated fucoidic sands: (i) the sorption was in principle characterized by linear isotherms and the corresponding retardation coefficients of 137Cs and 85Sr, depending on the type of sample, were approximately 13 or 44 and 5 or 15, respectively; (ii) the desorption was characterized by non-linear isotherms, and the retardation coefficients of the same radionuclides ranged between 23–50 and 5–25, respectively. The values of the hydrodynamic dispersion coefficients of these radionuclides varied between 0.43–1.2 cm2 h−1.

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Hydrodynamic dispersion characteristics of lateral inflow into a river tested by a laboratory model

Hydrology and Earth System Sciences ◽

10.5194/hess-13-217-2009 ◽

2009 ◽

Vol 13 (2) ◽

pp. 217-228 ◽

Cited By ~ 3

Author(s):

P. Y. Chou ◽

G. Wyseure

Keyword(s):

Pore Water ◽

Transport Model ◽

Column Experiment ◽

Breakthrough Curves ◽

Water Velocity ◽

Laboratory Model ◽

Hydrodynamic Dispersion ◽

Transport Parameter ◽

Transport Parameters ◽

Pore Water Velocity

Abstract. Groundwater and river-water have a different composition and interact in and below the riverbed. The riverbed-aquifer flux interactions have received growing interest because of their role in the exchange and transformation of nutrients and pollutants between rivers and the aquifer. In this research our main purpose is to identify the physical processes and characteristics needed for a numerical transport model, which includes the unsaturated recharge zone, the aquifer and the riverbed. In order to investigate such lateral groundwater inflow process, a laboratory J-shaped column experiment was designed. This study determined the transport parameters of the J-shaped column by fitting an analytical solution of the convective-dispersion equation for every flux on individual segments to the observed breakthrough curves of the resident concentration, and by inverse modelling for every flux simultaneously over the entire flow domain. The obtained transport-parameter relation was tested by numerical simulation using HYDRUS 2-D/3-D. Four steady-state flux conditions (i.e. 0.5 cm hr−1, 1 cm hr−1, 1.5 cm hr−1 and 2 cm hr−1) were applied, transport parameters including pore water velocity and dispersivity were determined for both unsaturated and saturated sections along the column. Results showed that under saturated conditions the dispersivity was fairly constant and independent of the flux. In contrast, dispersivity under unsaturated conditions was flux dependent and increased at lower flux. For our porous medium the dispersion coefficient related best to the quotient of the pore water velocity divided by the water content. A simulation model of riverbed-aquifer flux interaction should take this into account.

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Effects of Nonequilibrium Adsorption on Nuclide Transport in a Porous Rock

MRS Proceedings ◽

10.1557/proc-333-739 ◽

1993 ◽

Vol 333 ◽

Cited By ~ 1

Author(s):

Shi-Ping Teng ◽

Ching-Hor Lee

Keyword(s):

Analytical Solution ◽

Concentration Profile ◽

Solid Phase ◽

Radioactive Decay ◽

Breakthrough Curves ◽

Equilibrium Adsorption ◽

Hydrodynamic Dispersion ◽

Advective Transport ◽

Porous Rock ◽

Adsorption Rates

ABSTRACTAn analytical solution covering the entire range of adsorption properties of rock has been derived for the migration of radiionuclide in a porous rock matrix. The analysis takes into account the advective transport, hydrodynamic dispersion, adsorption between solid phase and liquid phase, and the radioactive decay. For adsorption of nuclide within the rock, the effects of no adsorption, linear nonequilibrium adsorption, and linear equilibrium adsorption are integrated into a generic transient analytical solution. The results indicate that the assumption of equilibrium adsorption can result in underestimation of the concentration profile in the early stages of migration. However, both the equilibrium and nonequilibrium profiles eventually approach the same value. It is also noted that for the case of nonequilibrium adsorption, plateaus appear in the concentration profile of the breakthrough curves. The effects of different adsorption rates are also analyzed.

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Application of linear and non-linear P-sorption models for describing phosphate transport.

Netherlands Journal of Agricultural Science ◽

10.18174/njas.v37i4.16625 ◽

1989 ◽

Vol 37 (4) ◽

pp. 387-390

Author(s):

S.E.A.T.M. van der Zee ◽

F. Leus ◽

M.J.P.F. Louer

Keyword(s):

Linear Model ◽

Phosphate Transport ◽

Breakthrough Curves ◽

Sorption Model ◽

P Sorption ◽

Simple Linear Model ◽

Precipitation Model ◽

Linear Sorption ◽

Non Linear ◽

Good Agreement

Phosphate transport in small columns was described using a two-site linear sorption model and a non-linear adsorption-precipitation model. Both approaches gave reasonable to good agreement with experimental breakthrough curves. This indicates the applicability of the simple linear model for engineering purposes, besides the general use of the more complex non-linear model. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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Modeling of transport of radionuclides in beds of crushed crystalline rocks under equilibrium non-linear sorption isotherm conditions

Radiochimica Acta ◽

10.1524/ract.2010.1729 ◽

2010 ◽

Vol 98 (6) ◽

Cited By ~ 12

Author(s):

S. Palágyi ◽

Karel Stamberg

Keyword(s):

Sorption Isotherm ◽

Regression Function ◽

Breakthrough Curves ◽

Simple Method ◽

Pulse Input ◽

Advection Dispersion ◽

Freundlich Equation ◽

Linear Sorption ◽

Retardation Coefficient ◽

Non Linear

AbstractA simple method for fitting the values of the experimental breakthrough curves in the form of pulse response obtained in dynamic flow column experiments is presented. It is based on the equation obtained by the analytical solution of a 1-D advection-dispersion equation (ADE) under defined conditions (equilibrium dynamics, linear sorption isotherm, constant bed height, pulse input), where the concentration (or activity) dependence on the number of pore volumes is expressed explicitly. It is shown that the method can be used in the case of validity of a non-linear Freundlich sorption isotherm if the experimental data are fitted by means of a Newton-Raphson multidimensional non-linear regression procedure in which the regression function consists of the above mentioned ADE equation and of the equation for a retardation coefficient including the first derivative of the Freundlich equation. Values of four parameters, namely, Freundlich equation parameters (

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Rapid simultaneous determination of organophosphorus pesticides in human serum and urine by liquid chromatography-mass spectrometry

Vojnosanitetski pregled ◽

10.2298/vsp1009717z ◽

2010 ◽

Vol 67 (9) ◽

pp. 717-722

Author(s):

Milica Zlatkovic ◽

Miodrag Jovanovic ◽

Dragana Djordjevic ◽

Slavica Vucinic

Keyword(s):

Mass Spectrometry ◽

Liquid Chromatography ◽

Solid Phase ◽

Organophosphorus Pesticides ◽

Extraction Procedure ◽

Liquid Chromatography Mass Spectrometry ◽

Aim Analysis ◽

Constant Flow Rate ◽

Chromatography Mass Spectrometry

Background/Aim. Analysis of organophosphosphorus compounds and their metabolites in a biological material includes the use of numerous methods, covering both preparation of samples for analysis and their identification that is considered to be very complex. Low concentrations monitoring requires implementation of highly sensitive analytical techniques. The aim of this study was to develop and validate an original and sensitive method for the detection and quantitation of organophosphorus pesticides (dimethoate, diazinon, malathion and malaoxon) in human biological matrices (serum, urine). Methods. This method was based on a solid-phase extraction procedure, a chromatographic separation using an ACQUITY UPLC ? HSST3 column and mass spectrometric detection in the positve ion mode. Mobile phase: was consited of Solvent A (5 mM ammonium formate pH 3.0) and Solvent B (0.1% acetic formate in methanol), in a linear gradient (constant flow-rate 0.3 mL/min). Results. The standard curve was linear in the range of 0.05-5.00 mg/L for malathion and malaoxon, 0.10-5.00 mg/L for dimethoate and 0.05-2.50 mg/L for diazinon. The correlation coefficient was r ? 0.99. Extraction recoveries were satisfactory and ranged between 90-99%. The limits of detection (LOD) was between 0.007- 0.07 mg/L and the limits of quantitation (LOQ) ranged between 0.022-0.085 mg/L. Intra- and interassay precision and accuracy were satisfactory for all of the pesticides analyzed. Conclusion. The method of liquid chromatography - mass spectrometry is simple, accurate, and useful for the determination of organophosphorus pesticides in both clinical and forensic toxicology.

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218. Determination of Formaldehyde Using Solid Phase Microextraction for Both Instantaneous and Timeweighted Average Sampling

10.3320/1.2762606 ◽

1999 ◽

Author(s):

P.A. Martos ◽

J. Pawliszyn

Keyword(s):

Solid Phase Microextraction ◽

Solid Phase ◽

Average Sampling

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Modern determinants of endometrium hyperplastic processes pathogenesis

HEALTH OF WOMAN ◽

10.15574/hw.2016.111.137 ◽

2016 ◽

pp. 137-142

Author(s):

V.O. Benyuk ◽

◽

V.M. Goncharenko ◽

T.R. Nykoniuk ◽

◽

...

Keyword(s):

Conservative Therapy ◽

Solid Phase ◽

Research Direction ◽

Immunohistochemical Method ◽

Results Of Treatment ◽

Treatment And Prevention ◽

Receptor Phenotype ◽

The Relationship ◽

Endometrial Proliferation

The objective: to еxplore the relationship between the activity of endometrial proliferation and the state of the local immune response in the uterus in the conditions berprestasi process. Patients and methods. Examined 228 women of reproductive and perimenopausal age with endometrial pathology using ultrasound and then performing hysteroresectoscopy. Determination of the concentrations of the cytokines IL-1, IL-2, IL-6 and TNF was performed by solid phase ELISA. Results. Found a trend that confirms the loss of sensitivity to hormones at the stage of malignancy of the endometrium and can be used as diagnostic determinants in determining the nature of intrauterine pathology and criterion of the effectiveness of conservative therapy. Conclusion. Improving etiopatogenetice approach to the therapy of hyperplastic proce.sses of endometrium with determination of receptor phenotype of the endometrium is a research direction in modern gynecology, which will help to improve the results of treatment and prevention of intrauterine pathology. Key words: endometrial hyperplasia,the receptors for progesterone and estrogen, immunohistochemical method.

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Determination of Concrete Cube Strength from Used Samples / Určení Krychelné Pevnosti Betonu U Použitých Zkušebních Trámců

Transactions of the VŠB - Technical University of Ostrava Civil Engineering Series ◽

10.2478/v10160-012-0033-3 ◽

2012 ◽

Vol 12 (2) ◽

pp. 186-194 ◽

Cited By ~ 2

Author(s):

Oldřich Sucharda ◽

David Mikolášek ◽

Jiří Brožovský

Keyword(s):

Compressive Strength ◽

Concrete Beams ◽

Linear Analysis ◽

Bending Tests ◽

Cube Strength ◽

Non Linear ◽

Compressive Strength Of Concrete ◽

Concrete Cube

Abstract This paper deals with the determination of compressive strength of concrete. Cubes, cylinders and re-used test beams were tested. The concrete beams were first subjected to three-point or fourpoint bending tests and then used for determination of the compressive strength of concrete. Some concrete beams were reinforced, while others had no reinforcement. Accuracy of the experiments and calculations was verified in a non-linear analysis.

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