Transport Number Mismatch Induced Stacking of Swept Sample Zones for Microchip-Based Sample Concentration

2000 ◽  
pp. 295-298
Author(s):  
Yingjie Liu ◽  
Robert S. Foote ◽  
Stephen C. Jacobson ◽  
Roswitha S. Ramsey ◽  
J. Michael Ramsey
Keyword(s):  
Transport Number ◽  
Sample Concentration

scholarly journals Self-Powered Point-of-Care Device for Galvanic Cell-Based Sample Concentration Measurement

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2665
Author(s):  
Albert Álvarez-Carulla ◽  
Yaiza Montes-Cebrián ◽  
Jordi Colomer-Farrarons ◽  
Pere Lluís Miribel-Català
Keyword(s):  
Low Power ◽  
Point Of Care ◽  
Linear Sweep Voltammetry ◽  
Electronic System ◽  
Concentration Measurement ◽  
Galvanic Cell ◽  
Sample Concentration ◽  
Maximum Coefficient ◽  
Self Powered ◽  
Transfer Function Gain

A novel self-powered point-of-care low-power electronics approach for galvanic cell-based sample concentration measurement is presented. The electronic system harvests and senses at the same time from the single cell. The system implements a solution that is suitable in those scenarios where extreme low power is generated from the fuel cell. The proposed approach implements a capacitive-based method to perform a non-linear sweep voltammetry to the cell, but without the need to implement a potentiostat amplifier for that purpose. It provides a digital-user readable result without the need for external non-self-powered devices or instruments compared with other solutions. The system conception was validated for a particular case. The scenario consisted of the measurement of a NaCl solution as the electrolyte, which was related to the conductivity of the sample. The electronic reader continuously measured the current with a transfer function gain of 1.012 V mA−1. The overall system exhibited a maximum coefficient of variation of 6.1%, which was an improvement compared with the state-of-the-art. The proof of concept of this electronics system was validated with a maximum power consumption of 5.8 μW using commercial-off-the-self parts.

Joule Heating Induced Temperature Gradient Focusing for Microfluidic Concentration of Samples

2010 ◽  
Author(s):  
Zhengwei Ge ◽  
Chun Yang
Keyword(s):  
Temperature Gradient ◽  
Electric Field ◽  
Joule Heating ◽  
Field Experiments ◽  
Dc Voltage ◽  
Sample Concentration ◽  
Great Achievement ◽  
Temperature Gradient Focusing ◽  
Concentration Enhancement ◽  
High Frequency Ac

Microfluidic concentration of sample species is achieved using the temperature gradient focusing (TGF) in a microchannel with a step change in the cross-section under a pure direct current (DC) field or a combined alternating current (AC) and DC electric field. Experiments were carried out to study the effects of applied voltage, buffer concentration and channel size on sample concentration in the TGF processes. These effects were analyzed and summarized using a dimensionless Joule number that is introduced in this study. In addition, Joule number effect in the Poly-dimethylsiloxane (PDMS)/PDMS microdevice was compared with the PDMS/Glass microdevice. A more than 450-fold concentration enhancement was obtained within 75 seconds in the PDMS/PDMS microdevice. Results also showed that the high frequency AC electric field which contributes to produce the temperature gradient and reduces the required DC voltage for the sample concentration. The lower DC voltage has generated slower electroosmotic flow (EOF), which reduces the backpressure effect associated with the finite reservoir size. Finally, a more than 2500-fold concentration enhancement was obtained within 14 minutes in the PDMS/PDMS microdevice, which was a great achievement in this TGF technique using inherent Joule heating effects.

Transport Number Measurements in Silica

1985 ◽  
Vol 132 (2) ◽  
pp. 310-312 ◽  
Author(s):  
J. K. Srivastava ◽  
V. B. Tare ◽  
J. B. Wagner
Keyword(s):  
Transport Number

The structure and relative transport number of sulphonated polysulphone membranes

Desalination ◽  
1977 ◽  
Vol 24 (1-3) ◽  
pp. 191-192
Author(s):  
N. Vinnikova ◽  
G.B. Tanny
Keyword(s):  
Transport Number

scholarly journals Evaluation of direct reading photoionization detector performance under various operational parameters

2021 ◽  
Vol 8 (2) ◽  
pp. 123-128
Author(s):  
Amir Hossein Khoshakhlagh ◽  
Farideh Golbabaei ◽  
Mojtaba Beygzadeh ◽  
Francisco Carrasco-Marín ◽  
Seyed Jamaleddin Shahtaheri
Keyword(s):  
Relative Humidity ◽  
Dynamic Range ◽  
Reference Method ◽  
Operational Parameters ◽  
Direct Reading ◽  
Detector Performance ◽  
Vapor Detection ◽  
Sample Concentration ◽  
Photoionization Detector ◽  
Before And After

Background: A hand-held portable direct-reading monitor, including photoionization detector (PID) is renowned for its good sensitivity, considerable dynamic range, and nondestructive vapor detection ability in comparison to the tardy response of the PID in gas chromatography (GC), which its application has been restricted. In this study, the performance of a PID system (MultiRAE Lite) was evaluated as a replacement of GC in the measurement of toluene in a dynamic adsorption system. Methods: The test was done at different relative humidity levels (30%, 50%, and 80%), temperatures (21, 30, 40° C), and toluene concentrations (20, 100, 200, and 400 ppm). Results: The PID achieved 48% of all measurements meeting the comparison criterion. The results showed that the performance of the PID could be altered by the variables. The best performance of the PID was at temperature of 21° C, the relative humidity of 50%, and concentration of 200 ppm with the percentage of readings achieving the criterion of comparison to 58%, 54%, and 52%, respectively. The averages of the PID readings (mean ± SD at 200 ppm= 207.9 ± 8.7) were higher than the reference method measurements averages (mean ± SD at 200 ppm= 203.5 ± 5.8). The regression analysis of the toluene results from the PID and the reference method results indicated that the measurements were significantly correlated (r2 = 0.93). Conclusion: According to the results, the device response is linear. Therefore, the findings are acceptable in adsorption studies. In this way, the measurement of the sample concentration should be performed using the same instrument before and after the reactor in order to calculate the adsorption efficiency.

scholarly journals MEASUREMENT AND SIGNIFICANCE OF TRANSPORT NUMBER IN FUSED SALTS

1955 ◽  
Author(s):  
R.W. Laity ◽  
F.R. Duke
Keyword(s):  
Transport Number ◽  
Fused Salts

scholarly journals The nonlinear electromigration of analytes into confined spaces

2012 ◽  
Vol 468 (2146) ◽  
pp. 3139-3152 ◽  
Author(s):  
Zhen Chen ◽  
Sandip Ghosal
Keyword(s):  
Electric Field ◽  
Background Electrolyte ◽  
Ionic Transport ◽  
Wave Shape ◽  
One Dimensional ◽  
Sample Concentration ◽  
Confined Spaces ◽  
Electrokinetic Injection ◽  
Sudden Contraction ◽  
Uniform Background

We consider the problem of electromigration of a sample ion (analyte) within a uniform background electrolyte when the confining channel undergoes a sudden contraction. One example of such a situation arises in microfluidics in the electrokinetic injection of the analyte into a micro-capillary from a reservoir of much larger size. Here, the sample concentration propagates as a wave driven by the electric field. The dynamics is governed by the Nerst–Planck–Poisson system of equations for ionic transport. A reduced one-dimensional nonlinear equation, describing the evolution of the sample concentration, is derived. We integrate this equation numerically to obtain the evolution of the wave shape and determine how the injected mass depends on the sample concentration in the reservoir. It is shown that due to the nonlinear coupling of the ionic concentrations and the electric field, the concentration of the injected sample could be substantially less than the concentration of the sample in the reservoir.

Key factors in FTIR spectroscopic analysis of DNA: the sampling technique, pretreatment temperature and sample concentration

2018 ◽  
Vol 10 (21) ◽  
pp. 2436-2443 ◽  
Author(s):  
Yahong Han ◽  
Lujia Han ◽  
Yumei Yao ◽  
Yanfei Li ◽  
Xian Liu
Keyword(s):  
Molecular Weight ◽  
Fourier Transform ◽  
Ftir Spectroscopy ◽  
Deoxyribonucleic Acid ◽  
Spectroscopic Analysis ◽  
Sampling Technique ◽  
Key Factors ◽  
Sample Concentration ◽  
Pretreatment Temperature ◽  
Molecular Weight Of Dna

Fourier transform infrared (FTIR) spectroscopy has been considered as a powerful tool for analysing the characteristics of deoxyribonucleic acid (DNA) regardless of physical states, sample amounts and the molecular weight of DNA.

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