323 research outputs found
Yangi tahrirdagi konstitutsiyaning fuqorolarimiz hayotida tutgan o’rni (Konstitutsiya meniki, seniki, bizniki, konstitutsiya - barchamizniki)
Ushbu maqolada joriy yilning 30-aprel sanasida referendum orqali amaliyotga joriy etilishi kutilayotgan yangi konstitutsiya, konstitutsiyaga kiritilayotgan oʻzgartishlarning xalqimiz hayotidagi oʻrni, eski konstitutsiya va tahliliy konstitutsiya oʻrtasidagi asosiy farqlar, yangi konstitutsiyaning fuqorolarimiz hayotidagi ahamiyati haqida toʻxtalib oʻtamiz
Effect of electric load and dual atmosphere on the properties of an alkali containing diopside-based glass sealant for solid oxide cells
© 2019 Elsevier B.V. All rights reserved.A new alkali-containing diopside based glass-ceramic sealant for solid oxide cells was synthesized, characterized and tested. The composition was designed to match the coefficient of thermal expansion (CTE) of Crofer22APU interconnect. The sealant has a glass transition temperature of 600°C, a crystallization peak temperature of 850°C and a maximum shrinkage temperature of 700°C, thus suggesting effective densification prior to crystallization. The CTE of the glass-ceramic is 11.5 10-6 K-1, a value which is compatible with the CTE for Crofer22APU stainless steel. Crofer22APU/glass-ceramic/Crofer22APU joined samples were tested in simulated real-life operating conditions at 800°C in dual atmosphere under an applied voltage, monitoring the electrical resistivity. The effect of two different applied voltages (0.7V and 1.3V) was evaluated. A voltage of 1.3V led to a rapid decrease in the electrical resistivity during the test;such a drop was due to the formation of Cr2O3 “bridges” that connected the two Crofer22APU plates separated by the sealant. There was no decrease in the resistivity when a voltage of 0.7V was applied. Instead,resistivity value remained stable at around 105 Ω cm for the 100h test duration. The degradation mechanisms, due to both the alkali content and the applied voltage, are investigated and discussed.Peer reviewe
MAS-NMR studies of glasses and glass-ceramics based on a clinopyroxene-fluorapatite system
HYDRODYNAMIC CALCULATION OF JOINT WORK AND BARREL GAS WELLS BOTTOMHOLE FORMATION ZONE IN THE PRESENCE OF A LIQUID PHASE
Gas industry of Uzbekistan is planned to increase gas production to 60 billion. m3. To perform this task, along with the development of major new fields of research are related to the ability to maximize the performance of each individual well, which would reduce the cost of production of gas. A necessary condition for the increase of gas production from the well is to obtain reliable information about the possibilities of gas recovery beds.Gas industry of Uzbekistan is planned to increase gas production to 60 billion. m3. To perform this task, along with the development of major new fields of research are related to the ability to maximize the performance of each individual well, which would reduce the cost of production of gas. A necessary condition for the increase of gas production from the well is to obtain reliable information about the possibilities of gas recovery beds
MORPHOFUNCTIONAL CHARACTERISTICS OF CELLULAR ELEMENTS OF RAT TESTES UNDER THE INFLUENCE OF INSECTICIDE ROVIKURT
The purpose of the study was to study the characteristics of the response of germ and somatic cells to the action of rovicurt, as well as to study some aspects of the mechanism of this action.
The research materials were the new insecticide Rovicurt, produced by the company “Hinoin” (Hungary) in the form of a 20% emulsion solution, proposed as a systemic acaricide. It mixes well with most organic solvents and consists of 23% Ambush (permethrin) and 2% tetramethrin (C21H20Cl2O3+C17H25O4).
The experiment used white male and female rats weighing 150-200 g. To study this process, male rats (132 pcs.) were taken, subjected to a single action of rovicurt in doses of 380, 150, 75 mg/kg, as well as control animals. The studies were carried out on days 1, 3, 7, 14, 21 and 70 after exposure. And with repeated administration - doses of 38, 19 mg/kg for 2.5 months, as well as control animals.
Research methods. Samples of testicular tissue were fixed in Carnoy's fluid and 2.5% glutaraldehyde solution, followed by additional fixation with 1% osmium tetroxide solution, dehydrated in alcohols of increasing strength, embedded in paraffin and in a mixture of epons. Paraffin sections were stained with hematoxylin-eosin, semi-thin sections prepared on an LKB-4800 ultratome were stained with methylene blue.
Results. When exposed to rovicurt at a dose of 380 mg/kg, the proliferation of testicular stem cells (spermatogonia) is disrupted. This process is based on degenerative changes. Different populations of germ cells react differently to a single action of rovicurt (at doses of 75 and 159 mg/kg): differentiation of early and middle spermatids is suppressed, while late spermatids are activated. When exposed to pesticides in doses of 75, 150 and 380 mg/kg, damage to the genome of spermatogenic epithelial cells is observed.
Conclusion. With acute and chronic action of pyrethroids, a change in the fine structure of the synaptonemal complex occurs, a delay in the differentiation of spermatocytes and spermatids, the appearance of multinucleated cells, as well as structural changes in sustentocytes and specialized connections between neighboring sustentocytes and germ cells
Some Suggestions to Reduce the Risk of Being into a Violent Situation
In this article was analyzed the state of crime in some countries (for some crimes). Based on a study of world statistics and experience, some suggestions were made to minimize the risk of falling into a situation of violence.
 
Glass-ceramic sealant for solid oxide fuel cells application: Characterization and performance in dual atmosphere
This document is the Accepted Manuscript version of the following article: A. G. Sabato, G. Tempura, D. Montinaro, A. Chysanthou, M. Salvo, E. Bernardo, M. Secco, F. Meacetto, ‘Glass-ceramic sealant for solid oxide fuel cells application: characterization and performance in dual atmosphere’, Journal of Power Sources, Vol. 328:262-270, October 2016, doi: http://dx.doi.org/10.1016/j.jpowsour.2016.08.010. Published by Elsevier. This manuscript version is distributed distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-ND 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.Glass-ceramic composition was designed and tested for use as a sealant in solid oxide fuel cell (SOFC) planar stack design. The crystallization behaviour was investigated by calculating the Avrami parameter (n) and the activation energy for crystallization (Ec) was obtained. The calculated values for n and Ec were 3 and 413.5 kJ/mol respectively. The results of thermal analyses indicate that this composition shows no overlap between the sintering and crystallization stages and thus an almost pore-free sealant can be deposited and sintered at 850 °C in air for 30 min. A gas tightness test has been carried out at 800 °C for 1100 h in dual atmosphere (Ar-H2 and air) without recording any leakage. Morphological and crystalline phase analyses were conducted prior and following tests in dual atmospheres in order to assess the compatibility of the proposed sealant with the metallic interconnect.Peer reviewe
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Glasses and glass-ceramics of the system CaO-MgO-Al2O3-SiO2 obtained from natural sedimentary raw materials
Common and low-cost natural sedimentary raw materials such as ball clay, dolomite, quartz sand and diatomite were used as the main constituents for the production of glasses and glass-ceramics of the system CaO-MgO-Al2O3-SiO2. The crystallization of the glassy batch was promoted by the addition of a nucleation agent (TiO2). The crystallization sequence was examined by DTA, XRD, SEM, and thermal expansion analyses. Wollastonite and diopside are the main phases detected and the amount and grain size/shape of crystals were found to be strongly dependent on titania additions and on the annealing conditions. The characterization of relevant functional parameters of glass and glass-ceramic samples revealed interesting results
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