Hydrogen production using Al-Sn alloys prepared by rapid solidification

Air pollution produced by the direct burning of fossil fuels is a serious problem. Therefore, there is a vital demand for renewable and clean fuel replacements for future energy source. Hydrogen, which exhibits high calorific value and is a clean burning product, could be the first choice in the future, as it is a good-looking fuel for fuel cells where the electric energy is directly gotten by the electrochemical reactions of hydrogen and oxygen. Rapidly solidified Al100-x-Snx alloy X= (0, 25, 55, 75 all in wt.%) was prepared using melt spinning technique at 800 ºC. The structural and microstructural evolutions of the phases have been studied using X-ray powder diffraction (XRD) and the Rietveld method. Al45Sn55 alloy shows the best volume of hydrogen generation which is (531 ml), this alloy has the highest number of grains (1096) than other prepared alloys in its surface which examined through a Scanning electron microscope (SEM) and analyzed using an SPM data visualization and analysis tool (Gwyddion 2.32). Differential thermal analysis (DTA) was used for calculating melting temperature for all prepared alloys. Melting temperature reduced from 933.47 K for Al pure to 500.95 K in Al45Sn55 alloy. Temperature dependence of resistivity had been performed for all prepared alloys. Electrical properties of prepared alloys show the decrease in volume of the unit cell V with increasing VEC, which means that the volume of the first Brillouin zone increases by increasing VEC since they are inversely proportional to each other

Experimental modelling of evaporation and boiling processes in a two-phase thermosyphon

A model of a closed two-phase thermosyphon was developed to study thermo-physical processes in a thermosyphon thermal condition systems of energy-saturated equipment. This model differs from the known by reasoned choice of thermocouples installation providing sealing the device during operation. In addition, the program VI (Virtual Instrument) was created in graphical environment Labview for registration of the temperatures and pressure in the thermosyphon

Teachers’ Hidden Curriculum and its Role in Promoting Citizenship Values Among Primary School Students in the Kingdom of Saudi Arabia

The aim of this study is to examine the extent to which primary school teachers in the Eastern Region of the Kingdom of Saudi Arabia practice the hidden curriculum with their students. The study also aims to identify the role of these teachers’ practices in promoting citizenship values ​​in primary school students in the Saudi community, and to provide suggestions based on the results. The researcher used a mixed approach method, with the necessary data collected by applying a questionnaire to a stratified random sample of primary school principals.  Furthermore, personal interviews were conducted with a sample of primary school teachers to identify their practices of the hidden curriculum with students, which reflected behaviors that enhance citizenship values in primary school students. The study team prepared its tools, and its psychometric properties were verified before applying them to the sample. The study population   consisted of all teachers and school principals of public primary schools in the Eastern Region of the Kingdom of Saudi Arabia. The results identified the most common practices of the hidden curriculum that teachers apply with their students. The results of the study also revealed that there are statistically significant differences in school principals’ estimation of teachers’ practices of the hidden curriculum according to the variable “years of experience”, in favor of principals with more than 10 years of experience, while there are no statistically significant differences in school principals’ estimation of the teacher’s practices of the hidden curriculum according to the “gender” variable

Mineral and heavy metals content in tilapia fish (Oreochromis niloticus) collected from the River Nile in Damietta governorate, Egypt and evaluation of health risk from tilapia consumption

This study was conducted to determine heavy metals and trace elements content in tilapia fish collected from three sources in Damietta governorate, Egypt and to evaluate the human health risk due to tilapia consumption. Tilapia samples were collected from two locations in the River Nile stream, tow fish farms and two sluiceways. Health risk assessment was evaluated based on the consumption habits of adult human. The results revealed that all samples vary in elements concentrations. The calculation of human health risk revealed that the consumption of tilapia in the three tested area does not pose any health risk except for Selenium. It could be concluded that consumption of such fish may be a risk for consumers who eat fish more than one time per week. Consequently, precautions should be taken and warning against eating tilapia fish caught from these regions should be announced.This study was conducted to determine heavy metals and trace elements content in tilapia fish collected from three sources in Damietta governorate, Egypt and to evaluate the human health risk due to tilapia consumption. Tilapia samples were collected from two locations in the River Nile stream, tow fish farms and two sluiceways. Health risk assessment was evaluated based on the consumption habits of adult human. The results revealed that all samples vary in elements concentrations. The calculation of human health risk revealed that the consumption of tilapia in the three tested area does not pose any health risk except for Selenium. It could be concluded that consumption of such fish may be a risk for consumers who eat fish more than one time per week. Consequently, precautions should be taken and warning against eating tilapia fish caught from these regions should be announced

Extrato de Panax ginseng C.A. Meyer neutraliza o stress oxidativo em ratos alimentados com dieta contaminada com multi-micotoxinas

The current study was conducted to evaluate the protective effects of Panax ginseng extract (PGE)against the toxicity and oxidative stress in rats fed aflatoxin (AFs) and/or fumonisin (FB)-contaminateddiet. Eighty female Sprague-Dawley rats were divided into eight experimental groups included thecontrol group, the group treated orally with PGE (0.5 mg/kg b.w.) and the groups fed AFs (1.4 mg/kg diet) and/or FB (20 mg/kg b.w.) contaminated diet alone or plus PGE for 11 weeks. Blood, liverand kidney tissue samples were collected at the end of treatment period for biochemical andhistological studies. The results indicated that PGE increased super oxide dismutase (SOD) levelin liver; however, the other parameters were comparable to controls. Animals fed AFs and/or FBcontaminateddiet showed a significant increase in serum biochemical parameters and oxidativestress markers accompanied with a significant decrease in antioxidant parameters levels and asevere histological changes in the liver tissue. These changes were more pronounced in the groupfed AFs plus FB. PGE succeeded to induce a significant improvement in all biochemical parametersand the histological picture towards the control although it did not normalize them. It could beconcluded that PGE is a promise candidate against the exposure to multi-mycotoxins in food.O presente estudo foi conduzido para avaliar os efeitos protetores do extrato de Panax ginseng(PGE) contra a toxicidade e estresse oxidativo em ratos alimentados com aflatoxinas (AFs) e/oudieta contaminada por fumonisina (FB). Oitenta fêmeas de ratos Sprague-Dawley foram divididasem oito grupos experimentais, incluindo o grupo controle, o grupo tratado com PGE oralmente (0,5mg/kg de peso corporal) e os grupos alimentados com as dietas contaminadas de AFs (1,4 dieta mg/kg) e/ou FB (20 mg/kg de peso corporal) isoladas ou com mais PGE durante 11 semanas. Amostrasde sangue, do fígado e do tecido do rim foram recolhidas no final do período de tratamentopara estudos bioquímicos e histológicos. Os resultados indicaram que a PGE aumenta o nível desuperóxido dismutase (SOD) no fígado, no entanto, os outros parâmetros foram comparáveis aosdo grupo controle. Animais alimentados com dieta contaminada por AF e/ou FB mostraram umaumento significativo nos parâmetros bioquímicos séricos e marcadores de estresse oxidativo,acompanhados de uma diminuição significativa nos níveis de antioxidantes e nos parâmetros dealterações histológicas graves no tecido do fígado. Essas alterações foram mais pronunciadas nogrupo alimentado com AFs mais FB. PGE obteve sucesso quanto à introdução de uma melhoriasignificativa em todos os parâmetros bioquímicos e histológicos com relação ao grupo controle,embora não os tenha normalizado. Pode-se concluir que a PGE é uma promissora candidatacontra a exposição às multimicotoxinas em alimentos

The Effect of Heat Stress on Blood Picture of Japanese Quail

This study aimed to evaluate the effect of heat stress on quail hematological parameters. A total number of 300 Japanese quail chicks (Coturnix Coturnix japonica) of 28 days old were exposed to different levels of raising temperatures (22, 29, 34, 36 and 40 ºC) for 15 days. At 42 days old, blood samples were collected from 14 birds (7 males + 7 females) that were randomly selected. The samples were used for determining red blood cells count, hemoglobin concentration, packed cell volume, total and differential white blood cells count, heterophils/ lymphocyte (H/L) ratio, mean corpuscular hemoglobin, mean corpuscular volume and mean corpuscular hemoglobin concentration. The obtained results indicated that, rearing quail birds under high environmental conditions during fattening period has a great adverse effect on these blood parameters

An Adaptive Protection Scheme for Coordination of Distance and Directional Overcurrent Relays in Distribution Systems Based on a Modified School-Based Optimizer

This paper presents an adaptive protection scheme (APS) for solving the coordination problem that deals with coordination directional overcurrent relays (DOCRs) and distance relays second zone time, in relation to coordination with DOCRs. The coordination problem becomes more complex with the impact of renewable energy sources (RES) when added to the distribution grid. This leads to a change in the grid topology, caused by the on/off states of the distribution generators (DG). The frequency of topological changes in distribution grids poses a challenge to the power system’s protection components. The change in the state of DGs leads to malfunction in reliability and miscoordination between protection relays, since that causes a direct effect to the short circuit currents. This paper used the school-based optimization (SBO) algorithm, which simulates the educational process, in order to deal with coordination problems. That algorithm is modified (MSBO) by modified both learning and teaching processes. The IEEE 8-bus test system and IEEE 14-bus distribution network are used to validate the proposed coordination system’s effectiveness when dealing with the coordination process between distance and DOCRs, at both the near- and far-end in the typical topological grid and with DGs in working order

Реорганизация структуры управления предприятием

Цель работы провести анализ деятельности существующего предприятия и дать рекомендации по реорганизации и улучшению структуры управления предприятием. В процессе исследования проводились: рассмотрение и оценка деятельности компании АО "Связной Логистика". В результате исследования: дана оценка эффективности работы данной компании, выявлены проблемы, предложены направления их решения.The purpose of the work is to analyze the activities of the existing enterprise and to give recommendations on the reorganization and improvement of the enterprise management structure. In the course of the research, the following was conducted: review and evaluation of the activity of the company Svyaznoy Logistics JSC. As a result of the study: an assessment of the performance of this company was given, problems were identified, directions for solving them were suggeste