Ab – initio restricted Hartree - Fock method within the framework of large unit cell (LUC) formalism is used to investigate the electronic structure of Si and Ge nanocrystals. The surface and core properties are investigated. A large unit cell of 8 atoms is used in the present analysis. Cohesive energy, energy gap, conduction and valence band widths are obtained from the electronic structure calculations. The results are compared with available experimental data and theoretical results of other investigators. The calculated lattice constant is found to be slightly larger than the corresponding experimental value because we use only 8 atoms and we compared the results with that of the bulk crystals, nanoclusters are expected to have str

Oil well drilling fluid rheology, lubricity, swelling, and fluid loss control are all critical factors to take into account before beginning the hole's construction. Drilling fluids can be made smoother, more cost-effective, and more efficient by investigating and evaluating the effects of various nanoparticles including aluminum oxide (Al₂O₃) and iron oxide (Fe₂O₃) on their performance. A drilling fluid's performance can be assessed by comparing its baseline characteristics to those of nanoparticle (NPs) enhanced fluids. It was found that the drilling mud contained NPs in concentrations of 0,0.25, 0. 5, 0.75 and 1 g. According to the results, when drilling fluid was used without NPs, the coeff

This study was conducted to study the cytogenetic effect of both alcoholic and water extracts of propolis on mice. Three different samples of propolis were collected from three different regions of Iraq (Najaf, Arbil and Baghdad) to be used in this study. The cytotoxic effect of two different doses of each extracted sample was measured by employing cytogenetic analysis which included (mitotic index (MI), chromosomal aberrations (CAs), micronucleus index (MN) and sperm abnormalities). Results showed that significant increase in MI and significant reduction in MN, CAs and sperm abnormalities percentage were seen after treatment with both alcoholic and water extract of the three samples when compared with negative control, and alcoholic extrac

In this research work, a simulator with time-domain visualizers and configurable parameters using a continuous time simulation approach with Matlab R2019a is presented for modeling and investigating the performance of optical fiber and free-space quantum channels as a part of a generic quantum key distribution system simulator. The modeled optical fiber quantum channel is characterized with a maximum allowable distance of 150 km with 0.2 dB/km at =1550nm. While, at =900nm and =830nm the attenuation values are 2 dB/km and 3 dB/km respectively. The modeled free space quantum channel is characterized at 0.1 dB/km at =860 nm with maximum allowable distance of 150 km also. The simulator was investigated in terms of the execution of the BB84 prot

One of the most enduring expressions of urban poverty in developing countries is the proliferation of slums and informal settlements .these settlements have the most deplorable living and environmental conditions within the city and are characterized by inadequate water supply, squalid conditions of environmental sanitation .overcrowded and dilapidated habitation, hazardous location .insecure tenure and vulnerability to serious health risks among many others .its in recognition of the of the development challenges to significantly improve the lives of at least 800000 people allover the country So our objectives in this research are the ensuring of a durable improvement of housing conditions and housing environment of poor people

The aim of this study is to get practical evidence from the Egyptian business environment The Impact of Audit Committees Effectiveness and External Audit Quality on Timeliness of annual Financial Report. Design and methodology: The study based on the content analysis technique to examine the annual reports of a sample of (30) companies listed on the Egyptian Stock Exchange (EGX100) during the period (2016-2019) with a total of (120) respondents. To test the research hypotheses, the results of the study indicate that there is a negative significant impact of audit committees on timeliness of annual financial report. Moreover, while there is a negative impact on the quality of the external audit on the timing of issuing the annual

Background: The role of prophylactic antibiotics remains controversial. It is clear that actively facial fractures are considered as clean contaminated and should be treated with therapeutic antibiotics; however, there is widespread variability in the use, type, timing, and duration of prophylactic antibiotic administrated in practice today. There is an adverse effect of increased antibiotic resistance, as well as costs, it is important to review the current evidence for the role of prophylactic antibiotics in compound facial fractures. The purpose of this study is to evaluate the role and significance of preoperative, perioperative and postoperative antibiotic prophylaxis for patients when there is already an infective focus, such as co

Vascular plants that have been identified during the study seasons in the Island. The cultivated plants were 126 species belong to 103 genera and to 49 families of the year 2001-2002 . The natural vegetation in this Island has been subjected to a total disturbance and subsidence due to the comprehensive turbidity of the Island environment.Number of names of that natural vegetation has been mentioned in the study within the weed plants.The results of the study of the period of flowering and their attitudes show clear seasonal differences. During the cold months of winter, the number of the cultivated and the natural plants was at the rate of 15%.These kinds of flowers require high level of care to increase their numbers. While in the spring