Key generation for data cryptography is vital in wireless communications security. This key must be generated in a random way so that can not be regenerated by a third party other than the intended receiver. The random nature of the wireless channel is utilized to generate the encryption key. However, the randomness of wireless channels deteriorated over time due to channel aging which casing security threats, particularly for spatially correlated channels. In this paper, the effect of channel aging on the ciphering key generations is addressed. A proposed method to randomize the encryption key each coherence time is developed which decreases the correlation between keys generated at consecutive coherence times. When compared to the

This paper studied the behaviour of reinforced reactive powder concrete (RPC) two-way slabs under static load. The experimental program included testing three simply supported slabs of 1000 mm length, 1000 mm width, and 70 mm thickness. Tested specimens were of identical properties except their steel fibers volume ratio (0.5 %, 1 %, and 1.5 %). Static test results revealed that, increasing steel fibers volume ratio from 0.5% to 1% and from 1% to 1.5%, led to an increase in: first crack load by (32.2 % and 52.3 %), ultimate load by (36.1 % and 17.0 %), ultimate deflection by (33.6 % and 3.4 %), absorbed energy by (128 % and 20.2 %), and the ultimate strain by (1.1 % and 6.73 %). The stiffness and ductility of the specimens also increased. A

The effect of different cutting fluids on surface roughness of brass alloy workpiece during turning operation was carried out in this research. This was performed with different cutting speed, while other cutting parameters had been regarded as constants(feeding rate , and depth of cut). Surface roughness of machined parts that will be tested by electronic surface roughness tester .The results show that the standard coolant gives the best values of surface roughness for fixed cutting speed ,followed by sun flower oil that has approximately the same effect, while the air stream as a coolant gave unsatisfied results for the evaluation of surface roughness.

In the other hand the best values of surface roughness were recorded for max

The present study was set to demonstrate the prevalence of toxoplasmosis infection and its effects on patients with systemic  lupus erythematosus (SLE) through determining their serum levels of anti-dsDNA and IL-18 antibodies. For this purpose, the sera from 132 SLE and/or toxoplasmosis patients and 30 healthy women, were collected. The study sample was divided into four groups of SLE, toxoplasmosis, SLE coinfected with toxoplasmosis, and healthy control. Anti-Toxoplasma IgG antibodies were examined for all the samples using ELISA kit. The results showed a high mean level of anti-Toxoplasma IgG among SLE patients coinfected with toxoplasmosis (104.8792±12.31585pg/ml) in comparison to that in toxoplasmosis patients (91.1705±12.577

This study investigates the influence of silver oxide (Ag₂O) nanoparticles on the gas-sensing properties of carbon nanotube (CNT) and poly(3-hexylthiophene) (P3HT) composite films. The goal is to enhance the sensitivity and stability of CNT/P3HT-based gas sensors for nitrogen dioxide (NO₂) detection. CNTs and P3HT are composited at various mass ratios, followed by integrating Ag₂O nanoparticles to improve gas interaction and electronic properties. Structural and morphological analyses, including x-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive x-ray spectroscopy, ascertain the successful incorporation of Ag₂O into the composites and reveal its role in impr

The aim of this study is to compare the effects of three methods: problem-based learning (PBL), PBL with lecture method, and conventional teaching on the understanding of thermodynamics, group work and self-directed learning skills among physics undergraduates. The actual sample size comprises of 122 students, who were selected randomly from the Physics Department, College of Education in Iraq, for academic year 2011-2012. In this study, the pre and posttest were done and the instruments were administered to the students for data collection. Inferential statistics were employed to analyze data. The independent variables were the PBL, the PBL with lecture method, and the conventional teaching. Dependent variables of statistical analysis were

Changes in mechanical properties of material as a result of service in different conditions can be provided by mechanical testing to assist the estimation of current internal situation of these materials, or the degree of deterioration may exist in furnaces serviced at high temperature and exceed their design life. Because of the rarity works on austenitic stainless steel material type AISI 321H, in this work, ultimate tensile strength, yield strength, elongation, hardness, and absorbed energy by impact are evaluated based on experimental data obtained from mechanical testing. Samples of tubes are extracted from furnace belong to hydrotreaterunit, also samples from un-used tube material are used to make comparisons between these properti

In this paper the effect of nonthermal atmospheric argon plasma on the optical properties of the cadmium oxide CdO thin films prepared by chemical spray pyrolysis was studied. The prepared films were exposed to different time intervals (0, 5, 10, 15, 20) min. For every sample, the transmittance, Absorbance, absorption coefficient, energy gap, extinction coefficient and dielectric constant were studied. It is found that the transmittance and the energy gap increased with exposure time, and absorption. Absorption coefficient, extinction coefficient, dielectric constant decreased with time of exposure to the argon plasma

Abrus precatorius L. is an important medicinal plant belonging to family Fabaceae. The present study was conducted to perform pre-clinical safety evaluation and study the pharmacological effects of the ethanolic seeds extract of A. precatorius in management of pain, psychiatric and neurological conditions. Acute toxicity was performed to study the general behavioural pattern of mice after treatment with the test extract (single doses of 1000, 2000, 3000,4000,5000 mg/kg, body weight) and sub-acute toxicity studies were performed to study the toxic effects of the test extract (1000,2000,3000 mg/kg, per os for 14 days) on different haematological parameters, body and organ weight and histopathology of liver and kidney. The toxicological evalua

The effect of insecticide lamda cyhalothrin on Allium cepa L.root meristem were studied cytogenetically .Using three concentrations of the insecticide 5%, 7.5%, 10% at 6,12,24hours treatments . The insecticide significantly reduced the mitotic index at all concentrations. Moreover showed its ability to induced C – metaphase in 10% .The effects were also caused chromosome aberration like stickness in anaphase, telophase, binucleated cells, Micronuclei formation. These alternations indicating that this insecticide was effective in producing disturbance of spindle fibers.