scholarly journals Determination of Natural Flow Rates of Some Chickpea Varieties on Different Surfaces and Surface Angles

2021 ◽  
Vol 35 (3) ◽  
pp. 259-264
Author(s):  
Yusuf Çiftci ◽  
Keziban Yalçın Dokumacı ◽  
Mehmet Hakan Sonmete
Keyword(s):  
Flow Rates ◽  
Natural Flow

Determination of specific interfacial areas in swirled two-phase flow

1983 ◽  
Vol 48 (3) ◽  
pp. 842-853
Author(s):  
Kurt Winkler ◽  
František Kaštánek ◽  
Jan Kratochvíl
Keyword(s):  
Interfacial Area ◽  
Liquid Volume ◽  
Upward Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Mist Flow ◽  
Interfacial Areas ◽  
Correlation Parameters ◽  
Flow Components

Specific gas-liquid interfacial area in flow tubes 70 mm in diameter of the length 725 and 1 450 mm resp. containing various swirl bodies were measured for concurrent upward flow in the ranges of average gas (air) velocities 11 to 35 ms-1 and liquid flow rates 13 to 80 m3 m-2 h-1 using the method of CO2 absorption into NaOH solutions. Two different flow regimes were observed: slug flow swirled annular-mist flow. In the latter case the determination was carried out separately for the film and spray flow components, respectively. The obtained specific areas range between 500 to 20 000 m3 m-2. Correlation parameters are energy dissipation criteria, related to the geometrical reactor volume and to the static liquid volume in the reactor.

Determination of trace concentrations of copper by FIA-FAAS after preconcentration on chelating sorbents

1989 ◽  
Vol 54 (7) ◽  
pp. 1785-1794 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Josef Komárek ◽  
Zbyněk Zdráhal
Keyword(s):  
Sampling Frequency ◽  
Copper Determination ◽  
Flow Rates ◽  
Sample Injection ◽  
Injection Flow ◽  
Chelating Sorbents ◽  
Set Up ◽  
Trace Concentrations ◽  
Better Than

A FIA-FAAS apparatus containing a six-channel sorption equipment with five 3 x 26 mm microcolumns packed with Spheron Oxin 1 000, Ostsorb Oxin and Ostsorb DTTA was set up. Combined with sorption from 0.002M acetate buffer at pH 4.2 and desorption with 2M-HCl, copper can be determined at concentrations up to 100, 150 and 200 μg l-1, respectively. For sample and eluent flow rates of 5.0 and 4.0 ml min-1, respectively, and a sample injection time of 5 min, the limit of copper determination is LQ = 0.3 μg l-1, repeatability sr is better than 2% and recovery is R = 100 ± 2%. The enrichment factor is on the order of 102 and is a linear function of time (volume) of sample injection up to 5 min and of the sample injection flow rate up to 11 ml min-1 for Spheron Oxin 1 000 and Ostsorb DTTA. For times of sorption of 60 and 300 s, the sampling frequency is 70 and 35 samples/h, respectively. The parameters of the FIA-FAAS determination (acetylene-air flame) are comparable to or better than those achieved by ETA AAS. The method was applied to the determination of traces of copper in high-purity water.

scholarly journals Comparison of different models to calculate the viscosity of biogas and biomethane in order to accurately measure flow rates for conformity assessment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Karine Arrhenius ◽  
Oliver Büker
Keyword(s):  
Binary Mixtures ◽  
Flow Rate ◽  
Correction Method ◽  
Gas Mixtures ◽  
Conformity Assessment ◽  
Flow Rates ◽  
Unknown Composition

AbstractThe study presents an optimised method to correct flow rates measured with a LFE flowmeter pre-set on methane while used for gas mixtures of unknown composition at the time of the measurement. The method requires the correction of the flow rate using a factor based on the viscosity of the gas mixtures once the composition is accurately known. The method has several different possible applications inclusive for the sampling of biogas and biomethane onto sorbent tubes for conformity assessment for the determination of siloxanes, terpenes and VOC in general. Five models for the calculation of the viscosity of the gas mixtures were compared and the models were used for ten binary mixtures and four multi-component mixtures. The results of the evaluation of the different models showed that the correction method using the viscosity of the mixtures calculated with the model of Reichenberg and Carr showed the smallest biases for binary mixtures. For multi-component mixtures, the best results were obtained when using the models of Lucas and Carr.

Determination of the water use of two pairs of soybean isolines differing in stomatal frequency using a heat balance stem flow gauge

1995 ◽  
Vol 75 (1) ◽  
pp. 99-103 ◽  
Author(s):  
C. S. Tan ◽  
B. R. Buttery
Keyword(s):  
Soil Moisture ◽  
Water Use ◽  
Heat Balance ◽  
Sap Flow ◽  
Stomatal Frequency ◽  
Flow Rates ◽  
High Soil Moisture ◽  
Stem Flow ◽  
Glycine Max L

Using heat-balance stem flow gauges, we were able to measure directly and continuously the sap flow rates in two pairs of soybean [Glycine max (L.) Merr.] isolines differing in stomatal frequency. Plants with high stomatal frequency transpired significantly more water than the low stomatal frequency plants at high soil moisture levels. Under low soil moisture levels, the water use rate decreased greatly for the high stomatal frequency plants. Plants with low stomatal frequency were able to maintain greater sap flow rates than those with high stomatal frequency. Higher leaf temperatures associated with the low stomatal frequency plants were likely due to lower transpiration rates which reduced evaporative cooling especially under well-watered conditions. Key words:Glycine max (L.) Merr., transpiration, water deficits

TCA cycle flux estimates from NMR- and GC-MS-determined [13C]glutamate isotopomers in liver

1997 ◽  
Vol 272 (6) ◽  
pp. C2049-C2062 ◽  
Author(s):  
J. A. Vogt ◽  
D. M. Yarmush ◽  
Y. M. Yu ◽  
C. Zupke ◽  
A. J. Fischman ◽  
...  
Keyword(s):  
Tca Cycle ◽  
Gas Chromatography Mass Spectrometry ◽  
Flow Rates ◽  
13C Nuclear Magnetic Resonance ◽  
Two Factors ◽  
Subsequent Measurement ◽  
System 1 ◽  
Relative Flow

Infusion of 13C-labeled lactate into rabbits and the subsequent measurement of glutamate isotopomers by 13C nuclear magnetic resonance (NMR) spectroscopy enables one to calculate relative flow rates associated with the tricarboxylic acid (TCA) cycle, albeit with a lower precision than one would obtain using a perfused organ. Two factors contribute to the lower precision in the determination of relative flow rates for the in vivo system: 1) a poorly defined pyruvate input and 2) low levels of 13C-enriched oxaloacetate and acetyl-CoA isotopomers, which give rise to weaker glutamate isotopomer NMR signals. To help overcome these limitations, we introduce a procedure to 1) include experimental data from gas chromatography-mass spectrometry (GC-MS) and 2) account for the uncertainty in the labeling of the input to pyruvate by creating the labeling as a measurement that is subject to measurement error. The effects of the uncertainties in the input labeling, NMR data, and MS data are evaluated via a Monte Carlo method. The change in the precision of the relative fluxes for the cases of high/low NMR and high/low MS precision is given. An uncertainty in the lactate measurements of up to 10% does not add significantly to the imprecision of the relative flow rates.

Determination of Anode-Pore Tortuosity from Gas and Current Flow Rates in SOFCs

2009 ◽  
pp. 127-140
Author(s):  
V. Hugo Schmidt ◽  
Chih-Long Tsai ◽  
Laura Lediaev
Keyword(s):  
Current Flow ◽  
Flow Rates

Clearance of Levofloxacin by an in Vitro Model of Continuous Venovenous Hemodialysis (CVVHD)

2007 ◽  
Vol 30 (10) ◽  
pp. 889-895 ◽  
Author(s):  
S. Siewert ◽  
B. Drewelow ◽  
S.C. Mueller
Keyword(s):  
In Vitro Model ◽  
Urea Clearance ◽  
Flow Rates ◽  
Dialysate Flow ◽  
Dialysate Flow Rate ◽  
Continuous Venovenous Hemodialysis ◽  
Vitro Model ◽  
Positive Correlations

Information about the elimination and the adequate dosing of levofloxacin during renal replacement therapy is scarce. The aim of this study was to characterize in vitro the elimination of levofloxacin during continuous venovenous hemodialysis (CVVHD) and to investigate whether the CVVHD clearances of creatinine and urea are correlated with the levofloxacin clearance in order to facilitate dosage adjustments. An in vitro model of CVVHD was established using five dialyzer membranes at varying dialysate flow rates applied in the clinical setting (8, 16, 25, 33 and 41 ml/min). Plasma and dialysate samples were drawn for determination of levofloxacin, creatinine and urea concentrations to evaluate clearances by CVVHD. During CVVHD, the clearance of levofloxacin varied between 9.02 and 33.30 ml/min, depending on the chosen setup. Positive correlations (p<0.001) were received for: dialysate flow rate (QD) and creatinine/urea clearances (R>0.93); QD and levofloxacin clearance (R 0.59–0.71); levofloxacin and creatinine clearance (R 0.69–0.75); and levofloxacin and urea clearance (R 0.56–0.75) as well. When dosing critically ill patients, therefore, extracorporeal as well as total clearance of levofloxacin should be considered.

Experimental Determination of Two-Phase Flow Rates of Hydrocarbons Through Restrictions

2006 ◽  
Vol 84 (1) ◽  
pp. 40-53 ◽  
Author(s):  
S.M. Richardson ◽  
G. Saville ◽  
S.A. Fisher ◽  
A.J. Meredith ◽  
M.J. Dix
Keyword(s):  
Experimental Determination ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Rates

High Pressure Liquid Chromatographic Determination of Aflatoxins by Using Radial Compression Separation

1982 ◽  
Vol 65 (3) ◽  
pp. 665-671
Author(s):  
Eric C Shepherd ◽  
Timothy D Phillips ◽  
Norman D Heidelbaugh ◽  
A Wallace Hayes
Keyword(s):  
High Pressure ◽  
Retention Time ◽  
Rapid Determination ◽  
Chromatographic Determination ◽  
Peak Height ◽  
Radial Compression ◽  
Good Resolution ◽  
Separation System ◽  
Flow Rates

Abstract A rapid method for the determination of aflatoxins was developed using high pressure liquid chromatography and a radial compression separation system. A standard solution of aflatoxins B1, B1, G1, G2, and M1 was analyzed at flow rates of 2.0 and 6.0 mL/min. Retention times, peak heights, and peak areas were reproducible over a 3-day period. Coefficients of variation for aflatoxin B1 at 2.0 and 6.0 mL/min were, respectively, 1.04 and 0.87% (retention time); 2.9 and 4.7% (peak height); and 8.2 and 4.7% (peak area). At 6.0 mL/min there was an approximate 25% loss in sensitivity but a greater than 50% reduction in retention time. Separation of all the aflatoxins was excellent using a dual flow rate of 2.0 mL/min with a change to 8.0 mL/min at 15 min post-injection. The applicability of the radial compression separation system for the rapid determination of aflatoxins in human tissues was also tested. Spiked samples of liver, serum, and urine showed good resolution of all aflatoxin peaks at the higher flow rates.

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