In the present work the Buildup factor for gamma rays were studied in shields from epoxy reinforced by lead powder and by aluminum powder, for NaI(Tl) scintillation detector size ( ×? ), using two radioactive sources (Co-60 and Cs-137). The shields which are used (epoxy reinforced by lead powder with concentration (10-60)% and epoxy reinforced by aluminum powder with concentration (10-50)% by thick (6mm) and epoxy reinforced by lead powder with concentration (50%) with thick (2,4,6,8,10)mm. The experimental results show that: The linear absorption factor and Buildup factor increase with increase the concentration for the powders which used in reinforcement and high for aluminum powder than the lead powder and decrease with inc

Acinetobacter baumannii ability to form biofilm makes it to be opportunistic pathogen causing of nosocomial infections and to be good survivor in adverse environmental conditions including medical devices and hospital environments. Six isolates of A. baumannii were isolated from drinking water and tested to investigate biofilm formation capacity on three different type of abiotic surface, also several factors were examined such as hydrophobicity, PH and temperature. All A. baumannii isolates displayed a positive biofilm on congored aga test CRA (pigmented colonies with black color) and Christensen's test (adhesive layer of stained material to the inside surface of the tube).The obtained data of microbial adhesion to hydrocarbons assay (MATH

ABSTRACT Purpose: the aim of this in vitro study was to compare the marginal gap and internal fitness between single crowns and the crowns within three-unit bridges of zirconium fabricated by CAD-CAM system. Materials and methods: A standard model from ivoclar company was used as a pattern to simulate three-units bridge (upper first molar and upper first premolar) as abutments used to fabricate stone models, eight single crowns for premolar and eight of three units bridges. Crowns and bridges fabricated by CAD-CAM system were cemented on their respective stone models then sectioned at the mid-point buccolingaully and misiodistaly and examined under stereomicroscope. Result: the marginal gap in premolar crowns and premolar within bridge we

We demonstrate a behavior of laser pulse grows through fiber laser inside and output cavity with a soliton fiber laser based on the multi-wall carbon nanotube saturable absorber (SA), we investigate the effects of a saturable absorber parameter on the mode-locking of a realistic Erbium fiber ring laser. Generalized nonlinear Schrodinger equation including the nonlinear effects as gain dispersion, second anomalous group velocity dispersion (GVD), self phase modulation (SPM), and two photon absorption used to describe pulse evolution. An analytical method has been used to understand and to quantify the role of the SA parameter on the propagation dynamics of pulse laser. We compute the chirp, power, width and phase of the soliton for range

Background: Bone mineral density (BMD) has been assessed using Dual-Energy X-ray absorptiometry (DEXA). This procedure is considered to be of vital importance in assessing the general condition of individuals concerning their skeletal mineralization. BMD is measured according to the results of the DEXA examination of the vertebral column and pelvis. Although diabetes mellitus (D.M.)is known to affect BMD, the information regarding this relationship is not currently particularly clear. Objective: This study concentrates on the point that the assessment of BMD for the vertebral column is insuffi-cient to give a realistic and correct picture of the mineralization of the remaining part of the skeleton. Besides, this study elicited a gen

This study investigates the role of Enterprise Resources Planning (ERP) systems in improving human resources management (HRM) processes. The rapid environmental changes led to increased demand on the ERP systems, which have changed the manual effort to technology-based processes, providing solutions focusing on the integration of all departments to achieve goals for the entire organization. HRM processes are mainly made up of two classes: strategic and operational HRM. An ERP system works to integrate both of them, making HRM processes more efficient, effective and feasible to provide support to the organization as a whole (inside and outside). In this article, a modest framework is proposed to describe HRM process integrity in relation to

The article emphasizes that 3D stochastic positive linear system with delays is asymptotically stable and depends on the sum of the system matrices and at the same time independent on the values and numbers of the delays. Moreover, the asymptotic stability test of this system with delays can be abridged to the check of its corresponding 2D stochastic positive linear systems without delays. Many theorems were applied to prove that asymptotic stability for 3D stochastic positive linear systems with delays are equivalent to 2D stochastic positive linear systems without delays. The efficiency of the given methods is illustrated on some numerical examples. HIGHLIGHTS Various theorems were applied to prove the asymptoti

An investigation was conducted for the study of extraction of metal ions using aqueous biphasic systems. The extraction of iron, zinc and copper from aqueous sulphate media at different kinds of extractants SCN− , Cl- and I- , different values of pH of the feed solution, phase ratio, concentration of metals, concentration of extractant, concentration of polymer, and concentration of salt was investigated. Atomic absorption spectrophotometer was used to measure the concentration of iron, zinc and copper in the aqueous phase throughout the experiments. The results of the extraction experiments showed the use of SCN− as extractant, pH=2.5, phase ratio=1.5, concentration of metals 1g/l, concentration of extractant 0.06 %, concentration o

Nowadays, the power plant is changing the power industry from a centralized and vertically integrated form into regional, competitive and functionally separate units. This is done with the future aims of increasing efficiency by better management and better employment of existing equipment and lower price of electricity to all types of customers while retaining a reliable system. This research is aimed to solve the optimal power flow (OPF) problem. The OPF is used to minimize the total generations fuel cost function. Optimal power flow may be single objective or multi objective function. In this thesis, an attempt is made to minimize the objective function with keeping the voltages magnitudes of all load buses, real outp