Separation of isotopes of light elements in a gas-solid-phase system. 1. Isotope effects in a hydrogen-metal hydride and intermetallic-compound hydride system

Atomic Energy ◽  
1998 ◽  
Vol 84 (2) ◽  
pp. 114-121 ◽  
Author(s):  
B. M. Andreev ◽  
É. P. Magomedbekov ◽  
I. L. Selivanenko
Keyword(s):  
Intermetallic Compound ◽  
Metal Hydride ◽  
Solid Phase ◽  
Isotope Effects ◽  
Phase System ◽  
Light Elements ◽  
Separation Of Isotopes ◽  
System 1

scholarly journals INVESTIGATION OF EFFECTS OF HEAT RELEASE IN ELECTROCHEMICAL SYSTEMS AND THEIR USE IN TECHNOLOGIES FOR PRODUCTION OF ENERGY-INTENSIVE SOURCES FOR AIRCRAFT

2019 ◽  
Vol 62 (1) ◽  
pp. 46-53 ◽  
Author(s):  
Yuri N. Shalimov ◽  
Igor K. Shuklin ◽  
Vladimir I. Parfenyuk ◽  
Vladimir I. Korolkov ◽  
Alexander V. Russu ◽  
...  
Keyword(s):  
Porous Structure ◽  
Metal Hydride ◽  
Thermal Effects ◽  
Power Plants ◽  
Hydrogen Reduction ◽  
Solid Phase ◽  
Transport Systems ◽  
Phase System ◽  
Electrochemical Systems ◽  
Kinetics Of

The search for new, more energy-intensive types of fuel for the operation of the power plants of aircraft is the most important task in aviation. The unique fuel that has no analogues is hydrogen. The paper attempts to substantiate the technology of metal hydride hydrogen storage in electrochemical systems based on aluminum and its alloys as the most affordable materials from fossil metals, since the traditional methods based on the use of cylinders and cryostats are not effective in transport systems. It is shown that the volumetric storage of hydrogen in the porous structure of metals with the formation of hydrides on atomic bond defects is maximally suitable for the implementation of the system, eliminating the excessive pressure and the low temperatures. The porous structure of the material provides both a high degree of availability of the electrolyte solution to the electrode for the accumulation of hydrides in the entire volume of the metal, and not only on its surface, but also the conditions for the realization of the reduction effect that excludes the explosive nature of hydrogen extraction. The problem of increasing the temperature in the reaction zone, which sometimes causes a slowdown in the rate of certain stages of the electrochemical process, is considered. Using the example of galvanic chrome plating, it has been established that an increase in the temperature inhibits the process of the reducing of the metallic chromium. Therefore, the detailed account of the thermal effects in the electrochemical system allows us to determine the mechanism of the processes. The work revealed that the thermal effects arising at the cathode determine the kinetics of the hydrogen reduction processes during the formation of a hydride. And the thermal effects at the anode determine the kinetics of the formation of a porous structure in the metal. The authors proposed to use the principle of action associated with the transition to the technologies of the volumetric storage of hydrogen in a solid-phase system based on a metal hydride compound for the formation of a new class of aircraft - diaplan.

Interphase distribution of 2-furylethylenes

1985 ◽  
Vol 50 (8) ◽  
pp. 1642-1647 ◽  
Author(s):  
Štefan Baláž ◽  
Anton Kuchár ◽  
Ernest Šturdík ◽  
Michal Rosenberg ◽  
Ladislav Štibrányi ◽  
...  
Keyword(s):  
Partition Coefficient ◽  
Partition Coefficients ◽  
Transport Rate ◽  
Phase System ◽  
Two Phase ◽  
Interphase Distribution ◽  
Distribution Kinetics ◽  
System 1 ◽  
Kinetics Of

The distribution kinetics of 35 2-furylethylene derivatives in two-phase system 1-octanol-water was investigated. The transport rate parameters in direction water-1-octanol (l1) and backwards (l2) are partition coefficient P = l1/l2 dependent according to equations l1 = logP - log(βP + 1) + const., l2 = -log(βP + 1) + const., const. = -5.600, β = 0.261. Importance of this finding for assesment of distribution of compounds under investigation in biosystems and also the suitability of the presented method for determination of partition coefficients are discussed.

Influence of biomass on hydrodynamics of an internal loop airlift reactor

2006 ◽  
Vol 60 (6) ◽  
Author(s):  
M. Juraščík ◽  
M. Hucík ◽  
I. Sikula ◽  
J. Annus ◽  
J. Markoš
Keyword(s):  
Aspergillus Niger ◽  
Gluconic Acid ◽  
Solid Phase ◽  
Biomass Concentration ◽  
Airlift Reactor ◽  
Phase System ◽  
Two Phase ◽  
Experimental Conditions ◽  
Internal Loop ◽  
Three Phase

AbstractThe effect of the biomass presence on the overall circulation velocity, the linear velocities both in the riser and the downcomer and the overall gas hold-up was studied in a three-phase internal loop airlift reactor (ILALR). The measured data were compared with those obtained using a two-phase system (air—water). All experiments were carried out in a 40 dm3 ILALR at six different biomass concentrations (ranging from 0 g dm−3 to 7.5 g dm−3), at a temperature of 30°C, under atmospheric pressure. Air and water were used as the gas and liquid model media, respectively. Pellets of Aspergillus niger produced during the fermentation of glucose to gluconic acid in the ILALR were considered solid phase. In addition, liquid velocities were measured during the fermentation of glucose to gluconic acid using Aspergillus niger. All measurements were performed in a bubble circulation regime. At given experimental conditions the effect of the biomass on the circulation velocities in the ILALR was negligible. However, increasing of the biomass concentration led to lower values of the total gas hold-up.

scholarly journals Comparing hydrogen absorption kinetics of the samples of intermetallic compound and metal hydride compact on its basis

2021 ◽  
Vol 2057 (1) ◽  
pp. 012043
Author(s):  
I A Romanov ◽  
V I Borzenko ◽  
A N Kazakov
Keyword(s):  
Intermetallic Compound ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
Reaction Rate ◽  
Nickel Foam ◽  
High Confidence ◽  
Compact Sample ◽  
Kinetics Of ◽  
Rate Controlling Step ◽  
Absorption Of Hydrogen

Abstract This work is devoted to an experimental study and comparison of the kinetics of hydrogen absorption by an intermetallic compound LaNi4.4Al0.3Fe0.3 in form of pure intermetallic compound free backfill and a compact based on it obtained by cold pressing with a spiral matrix of nickel-foam. To calculate the kinetic parameters of the hydrogen absorption reaction, the initial rates method is used. The PCT absorption isotherms are measured at temperatures of 313, 333, and 353 K. The experimental data are described with quite high confidence by the chosen model, which assumes that the reaction rate controlling step is the dissociative absorption of hydrogen on the surface of the a-phase. The rate of hydrogen absorption increases with increasing pressure drop and temperature. It is shown that the rate of hydrogen absorption by the sample of pure IMC is significantly less dependent on temperature compared to the compact sample. In addition, the reaction rate at temperatures of 313 and 333 K is higher for the free backfill sample, and at 353 K it is higher for the metal hydride compact. The values of the absorption constant and the activation energy of the hydrogen absorption reaction are determined for both samples.

Synthesis of Al – Fe/SiO2 and Al – Co/SiO2 catalysts by solid-phase method

2021 ◽  
Vol 2 ◽  
pp. 72-79
Author(s):  
V. A. Artyukh ◽  
◽  
V. N. Borshch ◽  
V. S. Yusupov ◽  
S. Ya. Zhuk ◽  
...  
Keyword(s):  
Intermetallic Compound ◽  
Solid Phase ◽  
Iron Silicide ◽  
Phase Method ◽  
Thermal Synthesis ◽  
Annealing Conditions ◽  
Developed Surface ◽  
Solid Phase Method ◽  
Sio2 Support ◽  
Fe3al Intermetallic

Powders of catalysts from aluminides Fe and Co on a SiO2 support (33.3 wt. %) were obtained by mechano-thermal synthesis. The formation of large powder fractions (> 100 μm) was experimentally established. The fractions of these fractions for Fe – Al – SiO2 and Co – Al – SiO2 respectively amounted to ~ 43 % and ~ 55 %, which is a positive result for further catalytic studies. After annealing the powders at 700 and 900 °C in vacuum, the SiO2 support and compounds: Co27Al73 (close in composition to CoAl3, Co4Al13 type intermetallic compounds), Fe3Al intermetallic compound with iron silicide type Fe0.9Si0.1 and compound Al0,3Fe3Si0.7 in small volumes. On the synthesis of cobalt aluminides, a conclusion has been made about more efficient annealing at 900 °C than at 700 °C. For Fe – Al – SiO2 powders, it is advisable to anneal in the temperature range 700 – 750 °C with the assumption that the SiO2 support influences the thermosynthesis of iron aluminides. An experimental analysis of the morphology and elemental composition of the surface of the obtained samples is presented. It was found that the catalyst powders have medium sphericity and angularity. Fe – Al – SiO2 powders have a more developed surface than Co – Al – SiO2. Lower intermetallics are predominantly formed on the surface of the Co – Al – SiO2 sample. The correction of the mechanical alloying modes by means of the fragmentation of the process, changes in the intensity of its parameters, and various annealing conditions for Co – Al – SiO2 and Fe – Al – SiO2 are proposed.

scholarly journals Application of Hollow Fibre-Liquid Phase Microextraction Technique for Isolation and Pre-Concentration of Pharmaceuticals in Water

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 311
Author(s):  
Lawrence Mzukisi Madikizela ◽  
Vusumzi Emmanuel Pakade ◽  
Somandla Ncube ◽  
Hlanganani Tutu ◽  
Luke Chimuka
Keyword(s):  
Liquid Phase ◽  
Solid Phase ◽  
Deep Eutectic Solvents ◽  
Enrichment Factors ◽  
Hollow Fibre ◽  
Phase System ◽  
Phase Extraction ◽  
Liquid Phase Microextraction ◽  
Three Phase ◽  
Set Up

In this article, a comprehensive review of applications of the hollow fibre-liquid phase microextraction (HF-LPME) for the isolation and pre-concentration of pharmaceuticals in water samples is presented. HF-LPME is simple, affordable, selective, and sensitive with high enrichment factors of up to 27,000-fold reported for pharmaceutical analysis. Both configurations (two- and three-phase extraction systems) of HF-LPME have been applied in the extraction of pharmaceuticals from water, with the three-phase system being more prominent. When compared to most common sample preparation techniques such as solid phase extraction, HF-LPME is a greener analytical chemistry process due to reduced solvent consumption, miniaturization, and the ability to automate. However, the automation comes at an added cost related to instrumental set-up, but a reduced cost is associated with lower reagent consumption as well as shortened overall workload and time. Currently, many researchers are investigating ionic liquids and deep eutectic solvents as environmentally friendly chemicals that could lead to full classification of HF-LPME as a green analytical procedure.

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