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1

Hydrogen Dilatation of V-Based Composite Membranes

Panichkin Alexander, Mamaeva Axaule, Kenzhegulov Aidar, Karboz Zhanar

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

767--772

EN

One of the problems limiting the use of vanadium as hydrogen permeable membranes is its high dilatation upon hydrogen dissolution in it. The information available for the dilatation coefficient value (Δυ/Ω) is contradictory, experimental information on the hydrogen solubility in vanadium within 100-1000 kPa at from 250 to 700°С is very limited. It does not enable to calculate the membrane dilatation. The article contains the measuring results for dilatation of strips made of vanadium foil 100 μm thick in a hydrogen atmosphere in the pressure range from 75 to 1000 kPa, temperatures from 250 to 700°С. The dilatation coefficient (Δυ/Ω) of polycrystalline vanadium was calculated based on the data obtained for dilatation and data previously published for the hydrogen concentration in the α-solid solution at 400°С. It is 0.165. Isobars for the temperature dependence of the hydrogen concentration in vanadium are calculated and constructed using the dilatation measuring results and the dilatation coefficient values. These data are agreed with theoretical and experimental data published previously. The limiting change in concentration and linear dimensions over the cross section of a hydrogen-permeable membrane from V was estimated at various temperatures and operating pressures at the membrane outlet based on the isobars plotted for temperature dependences of the CH/V. The conclusions are made on the optimal working conditions of Pd/V/Pd membranes when hydrogen is released from hydrogen-containing gas mixtures in accordance with Fick’s 1st law and data published previously for hydrogen concentration value at which solid hydrogen solutions in vanadium become brittle.

2

Theoretical approach to the physics of fuel cells

Wijewardena Gamalath K. A. I. L., Peiris B. M. P.

International Letters of Chemistry, Physics and Astronomy

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2012

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Vol. 2

15-27

EN

Ion transport rate of PAFC, AFC, PEMFC, DMFC and SOFC fuel cells under the influence of an electric field and concentration gradient were evaluated for static electrolytes. AFC are the best fuel cells for high er current applications while direct methanol fuel cells DMFC are the best for lower current applications AT lower temperatures. An equation for voltage output of a general fuel cell was obtained in terms of temperature and partial pressure of reactants. Performance of a 2D fuel cell was analyzed by simulating polarization and power curves for a fuel cell operating at 60 ?C with a limiting current density of 1.5 A cm- 2. The maximum power for this fuel cell was 8.454 W delivering 82% of maximum loading current density. When the temperature was increased by one third of its original value, the maximum power increased by 6.75% and at 60 ?C for a 10 times increment of partial pressure of reactants, the maximum power increased by 2.43%.The simulated power curves of the fuel cells were best described by cubic fits.

3

Wpływ ciśnienia na konwersję paliw gazowych w strukturalnych reaktorach katalitycznych

Budzianowski W. M.

Inżynieria i Aparatura Chemiczna

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2010

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Nr 1

21-22

PL

Zbadano wpływ wysokiego ciśnienia na konwersję i gradienty stężeniowe w procesie spalania i oksyformowania węglowodorów w strukturalnym reaktorze katalitycznym. Zdefiniowano, scharakteryzowano i wykorzystano w przykładzie wyrażenia S przydatne w analizie oporów dyfuzyjnych występujących w reaktorach strukturalnych wysokociśnieniowych. Zaproponowano metodykę nastawiania ciśnienia w reaktorach strukturalnych.

EN

The paper investigated the effect of high pressure on conversion and concentration gradients in combustion and oxyforming of hydrocarbons in structured catalytic reactors. The terms S were defined, characterized and used for the analysis of transport resistances exhibited in high-pressure structured reactors. The method for pressure elevation in structured reactors was proposed.

4

Variations in the physical properties of surf generated aerosols with altitude

Zieliński T.

Oceanologia

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2003

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No. 45 (4)

643-653

EN

Vertical profiles of marine aerosol size distribution and concentration in the marine boundary layer over surf zones depend strongly on wind speed, direction and duration as well as the sea bottom profile. The measurements in the present study were carried out in various seasons of the year with all these factors being taken into consideration. The data with respect to offshore winds were neglected in the calculations, since in such cases the major aerosol contribution was from terrigenous and anthropogenic particles. It was confirmed that in the range of wind speeds from 1 m s-1 to 12 m s-1 there were measurable differences in the concentrations, particularly in the size distribution of marine aerosol particles at two stations differing with respect to their sea bottom profiles.

5

A System for Measuring Vertical Concentration Profiles of Gaseous Pollutants, Using Carbon Dioxide as a Case Study

Micallef A., Deuchar C. N., Colls J. J.

International Journal of Occupational Safety and Ergonomics

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1998

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Vol. 4, No. 3

333--346

EN

An electronically-controlled sampling system, characterised by its organ pipe design, has been developed for sampling air sequentially, at different heights within the breathing zone. Data are automatically logged at the different receptor levels, for the determination of the average vertical concentration profile of gaseous pollutants. The system has been coupled to a carbon dioxide monitor and used in a brief study of the spatial and temporal variation of indoor carbon dioxide concentration. The system can easily be extended for different heights or modified for use with other types of gas monitor. The results of a trial run, which was carried out in a coffee room, are presented and applications of the Organ Pipe Sequential Sampling (OPSS) system are discussed.