Diffusion Coefficient of Oxygen in Solid Copper by the Steady State Current Method using a Solid Electrolyte

1972 ◽  
Vol 63 (2) ◽  
pp. 70-73
Author(s):  
Avasarala Ramana ◽  
Vasudeo Tare
Keyword(s):  
Diffusion Coefficient ◽  
Steady State ◽  
Solid Electrolyte ◽  
Current Method ◽  
Steady State Current ◽  
Diffusion Coefficient Of Oxygen ◽  
Solid Copper

scholarly journals The Steady-State Transport of Oxygen through Hemoglobin Solutions

1966 ◽  
Vol 49 (4) ◽  
pp. 663-679 ◽  
Author(s):  
K. H. Keller ◽  
S. K. Friedlander
Keyword(s):  
Diffusion Coefficient ◽  
Brownian Motion ◽  
Steady State ◽  
Effective Diffusion ◽  
Close Correlation ◽  
Oxygen Electrode ◽  
Low Oxygen ◽  
Diffusion Rates ◽  
Oxygen Tensions ◽  
Diffusion Coefficient Of Oxygen

The steady-state transport of oxygen through hemoglobin solutions was studied to identify the mechanism of the diffusion augmentation observed at low oxygen tensions. A novel technique employing a platinum-silver oxygen electrode was developed to measure the effective diffusion coefficient of oxygen in steady-state transport. The measurements were made over a wider range of hemoglobin and oxygen concentrations than previously reported. Values of the Brownian motion diffusion coefficient of oxygen in hemoglobin solution were obtained as well as measurements of facilitated transport at low oxygen tensions. Transport rates up to ten times greater than ordinary diffusion rates were found. Predictions of oxygen flux were made assuming that the oxyhemoglobin transport coefficient was equal to the Brownian motion diffusivity which was measured in a separate set of experiments. The close correlation between prediction and experiment indicates that the diffusion of oxyhemoglobin is the mechanism by which steady-state oxygen transport is facilitated.

Nanocomposite Based Electrolytes for Lithium-Ion Batteries

1999 ◽  
Vol 575 ◽  
Author(s):  
M.W. Riley ◽  
P.S. Fedkiw ◽  
S.A. Khan
Keyword(s):  
Steady State ◽  
Elastic Modulus ◽  
Lithium Ion Batteries ◽  
Room Temperature ◽  
Ethylene Carbonate ◽  
Lithium Ion ◽  
Current Method ◽  
Transference Numbers ◽  
Steady State Current ◽  
Nanocomposite Electrolytes

ABSTRACTNanocomposite electrolytes based on lithium hectorite (LiHect) clay dispersed in highdielectric organic solvents such as ethylene carbonate (EC) and propylene carbonate (PC) are shown to exhibit room-temperature conductivities exceeding 10−4 S/cm. The LiHect-based composites reveal lithium ion transference numbers of ∼0.8, as measured by the steady-state current method. In addition, dynamic rheological techniques show this system to be mechanically stable with elastic modulus G' exceeding 107 dynes/cm 2 and yield stress exceeding 104 dynes/cm2.

scholarly journals Laser Induced Temperature Perturbation on Ultramicroelectrodes: Unsupported Solutions in Nonaqueous Methanol

2022 ◽  
Author(s):  
Salvador Gutierrez-Portocarrero ◽  
Pradeep Subedi ◽  
Mario A. Alpuche-Aviles
Keyword(s):  
Diffusion Coefficient ◽  
Steady State ◽  
Temperature Dependence ◽  
Continuous Wave ◽  
High Resistivity ◽  
Temperature Perturbation ◽  
Colloidal Systems ◽  
Steady State Current ◽  
Before And After ◽  
Electron Transfer Processes

Abstract Temperature dependence studies of electrochemical parameters provide insight into electron transfer processes. In cases where adding excess electrolyte experimental causes complications colloidal systems, organic or biological samples it is preferable to deal with the high resistivity of the medium. We validate the use of unsupported and weakly supported solutions in thermoelectrochemical experiments. The temperature dependence of the diffusion coefficient allows calibration of the steady-state current to measure changes when a continuous wave (CW) ultraviolet laser, λ=325 nm, illuminates an ultramicroelectrode (UME) from the front. Calibrating the steady-state current ratios before and after heating with a thermostatic bath allows temperature measurements within an accuracy of 0.6 K. The solutions are without supporting electrolytes in methanol, a volatile solvent, and we use a model that accurately describes the viscosity and temperature dependence of the solvent. We calculated the temperature and derived an equation to estimate the temperature measurement error. A numeric method yields satisfactory results, considering the changes for both diffusion coefficients and viscosity explicitly, and predict the thermostatic temperature bath, agreeing with the theoretical model's error. In unsupported solutions, the ferrocene diffusion coefficient and the iodide apparent diffusion coefficient follow the expected increase with temperature. Under CW laser illumination ΔT=4±1 K.

scholarly journals Transient Current Density in a Pair of Long Parallel Conductors

2021 ◽  
Vol 11 (15) ◽  
pp. 6920
Author(s):  
Oldřich Coufal
Keyword(s):  
Steady State ◽  
Cross Section ◽  
Current Density ◽  
Circular Cross Section ◽  
Transient Current ◽  
Constant Current ◽  
Voltage Source ◽  
Sinusoidal Voltage ◽  
Steady State Current ◽  
Maximum Current

Two infinitely long parallel conductors of arbitrary cross section connected to a voltage source form a loop. If the source voltage depends on time, then due to induction there is no constant current density in the loop conductors. It is only recently that a method has been published for accurately calculating current density in a group of long parallel conductors. The method has thus far been applied to the calculation of steady-state current density in a loop connected to a sinusoidal voltage source. In the present article, the method is used for an accurate calculation of transient current using transient current density. The transient current is analysed when connecting and short-circuiting the sources of sinusoidal, constant and sawtooth voltages. For circular cross section conductors, the dependences of maximum current density, maximum current and the time of achieving steady state on the source frequency, the distance of the conductors and their resistivity when connecting the source of sinusoidal voltage are examined.

The stirring of the medium by bull spermatozoa

1963 ◽  
Vol 157 (969) ◽  
pp. 461-472 ◽  
Keyword(s):  
Diffusion Coefficient ◽  
Short Range ◽  
Short Range Order ◽  
Effective Diffusion ◽  
Sperm Head ◽  
Special Shape ◽  
Bull Semen ◽  
Sperm Density ◽  
Bull Sperm ◽  
Diffusion Coefficient Of Oxygen

1. Bull semen diluted 1/5 or 1/10 respired at the same rate whether the manometers were stationary or shaken. 2. Respirometric experiments using a manometer flask of special shape showed that bull sperm suspensions achieve this result by increasing the effective diffusion coefficient of oxygen in the suspending medium by 900%. 3. The hypothesis is put forward ( a ) that these results are caused by the existence of short-range order, as opposed to disorder, in bull sperm suspensions, even at comparatively low sperm densities (dilution 1/8 to 1/20); ( b ) that this order produces group sperm velocities greater than those of isolated spermatozoa; and ( c ) that as a result, larger volumes of the suspending medium are convected with the ordered sperm groups, causing an augmented ‘diffusion’ of oxygen. 4. This hypothesis was examined by taking photomicrographs of sperm suspensions at different dilutions and temperatures and determining from them the distributions of (i) the distance between pairs of nearest spermatozoa; (ii) the angle of inclination of a sperm head relative to that of the spermatozoon nearest to it; and (iii) the relative position of the nearest spermatozoon. 5. Comparison of the observed distributions and the corresponding random ones showed that the spermatozoa attracted each other, so that transient sperm groups were formed, in which the spermatozoa tended to swim in the same direction. A reduction in temperature or sperm density decreased the sperm order.

scholarly journals Redox mediation at poly(o-aminophenol) coated electrodes: Mechanistic diagnosis from steady state polarization curves

2018 ◽  
Author(s):  
Gabriel Ybarra ◽  
Carlos Moina ◽  
María Inés Florit ◽  
Dionisio Posadas
Keyword(s):  
Steady State ◽  
Polarization Curve ◽  
Experimental Measurements ◽  
Steady State Current ◽  
Thermodynamical Parameters ◽  
Reduction And Oxidation ◽  
Mediated Reduction ◽  
Coated Electrodes ◽  
Current Potential ◽  
Potential Curves

<p class="PaperAbstract"><span lang="EN-US">In this work, the mediated reduction and oxidation of Fe(CN)<sub>6</sub><sup>3-/4-</sup> and Fe<sup>3+ </sup>in poly(o-aminophenol) coated electrodes is analyzed by means of diagnosis diagram based on the features of steady state current-potential curves. This analysis allows to identify the current determining process and to reproduce the experimental characteristics of the polarization curve from the relevant kinetic and thermodynamical parameters with a minimum amount of experimental measurements. </span></p>

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