Sizing Requirements for Flow-Through Geochemical Tests: Theoretical Considerations and Model Results

1989 ◽  
Vol 176 ◽  
Author(s):  
James D. Hoover ◽  
Edward C. Thornton
Keyword(s):  
Residence Time ◽  
Reaction Path ◽  
Transport Processes ◽  
Test Duration ◽  
Test Conditions ◽  
Reaction Zones ◽  
Time Requirements ◽  
Flow Through ◽  
Technical Basis

ABSTRACTA methodology for evaluating test apparatus size requirements has been applied to the sizing of flow-through tests used in the evaluation of coupled reaction and transport processes. The results of the sizing evaluation constrain the apparatus dimensions and test conditions capable of yielding results representative of the processes of interest.The size requirements of flow-through tests involving a system of simplified granite and groundwater were determined in order to demonstrate the feasibility and implications of sizing evaluations. Reaction path simulations were performed using the E03/6 codes at temperatures of 25°C, 100°C, and 200°C. The determination of reaction path as a function of time was then used to obtain minimum column residence time requirements. Simulation results indicate that column lengths required for development of quasistatic equilibrium reaction zones at 200°C are three times smaller than at 100°C, and over 36 times smaller than at 25°C.A range of possible combinations of column dimensions and flow rates for a set of model test conditions exist for a given residence time. The most appropriate combinations depend on the purpose of the test, the process of interest, and factors such as test duration, sampling requirements, and engineering limitations. Size and scale evaluations thus provide a technical basis for the design and construction of flow-through tests, and have profound implications for the interpretation of test results.

Precipitation and filtration of zinc, magnesium, copper and aluminium hydroxides

1982 ◽  
Vol 47 (12) ◽  
pp. 3362-3370
Author(s):  
Otakar Söhnel ◽  
Eva Matějčková
Keyword(s):  
Residence Time ◽  
Mean Residence Time ◽  
Filtration Resistance ◽  
Filtration Pressure ◽  
Bed Porosity ◽  
The Mean ◽  
Filtration Properties

Filtration properties of batchwise precipitated suspensions of Zn(OH)2, Mg(OH)2 and Cu(OH)2 and continuously precipitated Al(OH)3 were studied. For batchwise precipitated suspensions was verified the theoretically predicted dependence of specific filtration resistance on initial supersaturation and for the continuously precipitated Al(OH)3 the relation between the specific filtration resistance and the mean residence time of suspension in the reactor. Dependences were also recorded between the bed porosity and concentration of precipitated solutions, specific filtration resistance and used filtration pressure and the effect of aging of the batchwise precipitated suspension of Mg(OH)2on its filtration properties. The used CST method for determination of filtration characteristics of Zn(OH)2 suspension was also studied.

scholarly journals Determination of cross-sectional void fraction in a two-phase water flow through a PVC pipe

2021 ◽  
Vol 655 (1) ◽  
pp. 012024
Author(s):  
O.H. Ajesi ◽  
M.B. Latif ◽  
S.T. Gbenu ◽  
C. A. Onumejor ◽  
M. K. Fasasi ◽  
...  
Keyword(s):  
Water Flow ◽  
Void Fraction ◽  
Two Phase ◽  
Cross Sectional ◽  
Flow Through ◽  
Pvc Pipe ◽  
Phase Water

Bicarbonate and CO2 transport across the skin of the leopard frog, Rana pipiens: effect of PGF2alpha

1997 ◽  
Vol 272 (2) ◽  
pp. R640-R647 ◽  
Author(s):  
O. A. Candia ◽  
T. Yorio
Keyword(s):  
Methodological Approach ◽  
Transport Processes ◽  
Leopard Frog ◽  
Bicarbonate Transport ◽  
Amphibian Skin ◽  
Acid Base ◽  
Reliable Determination ◽  
Net Flux ◽  
Unidirectional Fluxes

The amphibian skin represents an important organ for osmoregulation and, like the mammalian kidney, maintains acid-base balance by secreting protons or base. However, the lack of a reliable and accurate method to measure the contribution of unidirectional fluxes of HCO3- ions to this mechanism has been an obstacle for the determination of the role of bicarbonate in epithelial acid-base homeostasis. Recently, one of us developed a method that allows for the reliable determination of transepithelial fluxes of bicarbonate, and this method was applied to determine unidirectional fluxes of (14)CO2 and H(14)CO3 under a variety of conditions. We report that the combined CO2 and HCO3- mucosal-to-serosal flux under 5% CO2 was 40% larger than the opposing flux, giving a net flux in the mucosal-to-serosal direction. This net flux was inhibited by acetazolamide. In CO2-free conditions, there was no detectable net flux; however, acetazolamide and PGF(2alpha) attenuated the mucosal-to-serosal flux and established an apparent secretion of HCO3-. A model is presented that depicts twelve vectors or components to the CO2 plus HCO3- fluxes in the frog skin. This model can accurately reproduce the experimental values measured from unidirectional fluxes of CO2 and HCO3- under a variety of conditions and can explain the effects of PGF(2alpha) on unidirectional 14C-labeled fluxes as a consequence of inhibition of H+ secretion to the apical bath, similar to what was previously suggested by our laboratory using a different methodological approach. The present method, utilizing radiolabeled HCO3-, may be useful as a means to evaluate the mechanism of action of hormones and drugs that may regulate acid-base homeostasis by altering proton and bicarbonate transport processes.

scholarly journals Experimental determination of noble gases and SF6, as tracers of CO2 flow through porous sandstone

2018 ◽  
Vol 480 ◽  
pp. 93-104 ◽  
Author(s):  
R. Kilgallon ◽  
S.M.V. Gilfillan ◽  
K. Edlmann ◽  
C.I. McDermott ◽  
M. Naylor ◽  
...  
Keyword(s):  
Experimental Determination ◽  
Noble Gases ◽  
Porous Sandstone ◽  
Flow Through ◽  
Co2 Flow

Flow-through pH-ISFET as detector in the determination of ammonia

1990 ◽  
Vol 231 ◽  
pp. 53-58 ◽  
Author(s):  
S. Alegret ◽  
J. Alonso ◽  
J. Bartroli ◽  
M. del Valle ◽  
N. Jaffrezic-Renault ◽  
...  
Keyword(s):  
Flow Through

Method for the simultaneous quantification of n-hexane metabolites: application to n-hexane metabolism determination

1996 ◽  
Vol 15 (6) ◽  
pp. 497-503 ◽  
Author(s):  
T. Soriano ◽  
M. Menéndez ◽  
P. Sanz ◽  
M. Repetto
Keyword(s):  
Similar Pattern ◽  
Analytical Procedure ◽  
Daily Basis ◽  
Practical Application ◽  
Simultaneous Quantification ◽  
Exposed Workers ◽  
Before And After ◽  
Time Requirements ◽  
The Difference

1 The described analytical procedure permits the simultaneous determination of the main n-hexane meta bolites in urine. 2-Hexanone, 2-hexanol, 2, 5-hexanediol and 2, 5-hexanedione, were chosen to dose the rats used in this study. All urine samples were collected and analysed on a daily basis, before and after acidic hydrolysis (pH 0.1) by GC/MS. 2-Hexanone, 2, 5-dimethylfurane, γ-valerolac tone and 2, 5-hexanedione were determined before hydro lysis ; 2-hexanol and 2, 5-hexanediol, after hydrolysis; and 5-hydroxy-2-hexanone and 4, 5-dihydroxy-2-hexanone were calculated by the difference between γ-valerolactone and 2, 5-hexanedione with and without hydrolysis, respectively. 2 A metabolic scheme was proposed reflecting the biotransformations undergone by the four compounds assayed. We consider 2, 5-dimethylfurane as a 'true metabolite' because the quantities detected were always greater before hydrolysis. 3 It has been reported that human and rat n-hexane metabolism follow a similar pattern. Therefore, as a practical application and without increasing either sample or time requirements, the simultaneous quantifi cation of the different metabolites and their excretion profile could provide better information about the metabolic situation of exposed workers than the determi nation of 2, 5-hexanedione alone. According to our experimental results, 4, 5-dihydroxy-2-hexanone itself would be a good toxicity indicator.

Velocity Profiles of Liquid Flow Through Circular Tubes and How They Affect Flow Measurement

1991 ◽  
Vol 113 (3) ◽  
pp. 206-210 ◽  
Author(s):  
D. Yogi Goswami
Keyword(s):  
Transition Region ◽  
Laser Doppler Velocimetry ◽  
Flow Measurement ◽  
Velocity Profiles ◽  
Turbulent Regime ◽  
Flow Meters ◽  
Circular Tubes ◽  
Flow Through ◽  
Hydrogen Bubble Technique

This paper analyzes velocity profiles for flow through circular tubes in laminar, turbulent, and transition region flows and how they affect measurement by flow-meters. Experimental measurements of velocity profiles across the cross-section of straight circular tubes were made using laser doppler velocimetry. In addition, flow visualization was done using the hydrogen bubble technique. Velocity profiles in the laminar and the turbulent flow are quite predictable which allow the determination of meter factors for accurate flow measurement. However, the profiles can not be predicted at all in the transition region. Therefore, for the accuracy of the flowmeter, it must be ensured that the flow is completely in the laminar regime or completely in the turbulent regime. In the laminar flow a bend, even at a large distance, affects the meter factor. The paper also discusses some strategies to restructure the flow to avoid the transition region.

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