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

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. &nbsp

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

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

Glasses and glass-ceramics in the CaO–MgO–SiO2 system: diopside containing compositions - a brief review

Among different silicate systems, CaO−MgO−SiO2 is the one of the most promising due to abundance of reagents, easier fabrication, improved performance, and wide range of application. Analysis of the current literature sources denotes that phase diagram of CaO−MgO−SiO2 system is regularly used by researchers worldwide as constitutive model for synthesis glass-ceramic materials (GCs) possessing an adequate combination of high chemical durability, mechanical and electrical properties. In recent years, materials from this system attracted extra interest for applications in bone tissue repair owing to their ability to induce hydroxyapatite formation in contact with body fluids and to be resorbed in controllable degradation rate. In this brief review diopside containing compositions are specifically discussed. The main goal is to provide critical analysis of the experimental trials directed on synthesis of GC materials in the CaO−MgO−SiO2 system. Glass compositions were analysed through the standpoint of their location in the relevant region, or phase field, within a phase diagram to guide GC production and to make educated choices of compositions and processing parameters. Apart from Introduction and Conclusions this review comprises five consecutive parts. In the first part, constitution of phase diagram of CaO−MgO−SiO2 system is comprehensively discussed with connection to melts’ crystallization path and crystalline phase formation. In the second part, special attentiveness is drawn towards diopside- containing GCs produced from wastes and non-expensive natural raw materials. In this regard and taking into consideration presence of Al2O3 in the majority types of wastes, cross sections of CaO−MgO−SiO2−Al2O3 system with 10, 15 and 20% of Al2O3 are suggested to utilize when anticipating ultimate crystalline phase(s) formation. The following parts of this review are mostly addressed to recent advancement in producing optimized diopside-containing glass–ceramic biomaterials for bone repair as well as innovative sealants for solid oxide fuel cells (SOFC). Likewise, some other active areas of research and application for diopside containing GC compositions are briefly discussed.publishe

Dolomite-foamed bioactive silicate scaffolds for bone tissue repair

The use of three-dimensional (3D) scaffolds is recognized worldwide as a valuable biomedical approach for promoting tissue regeneration in critical-size bone defects. Over the last 50 years, bioactive glasses have been intensively investigated in a wide range of different clinical applications, from orthopedics to soft tissue healing. Bioactive glasses exhibit the unique capability to chemically bond to the host tissue and, furthermore, their processing versatility makes them very appealing due to the availability of different manufacturing techniques for the production of porous and interconnected synthetic bone grafts able to support new tissue growth over the whole duration of the treatment. As a novel contribution to the broad field of scaffold manufacturing, we report here an effective and relatively easy method to produce silicate glass-derived scaffolds by using, for the first time in the biomedical field, dolomite powder as a foaming agent for the formation of 3D bone-like porous structures. Morphological/structural features, crystallization behavior, and in vitro bioactivity in a simulated body fluid (SBF) were investigated. All the tested scaffolds were found to fulfil the minimum requirements that a scaffold for osseous repair should exhibit, including porosity (65-83 vol. %) and compressive strength (1.3-3.9 MPa) comparable to those of cancellous bone, as well as hydroxyapatite-forming ability (bioactivity). This study proves the suitability of a dolomite-foaming method for the production of potentially suitable bone grafts based on bioactive glass systems