Ultrasonic absorption, velocity, viscosity, adiabatic compressibility, relaxation time and relaxation amplitude measurements are reported on different concentrations of poly(acrylic acid) solutions in common solvent water using pulsed ultrasonic apparatus technique operating at 26 kHz and 30 ºC. Results show an increase of velocity, viscosity, and absorption coefficient ،relaxation time and relaxation amplitude values with the increasing concentrations of the poly(acrylic acid) solutions, which might be the result of structural fluctuations of polymer molecules such as the segmental motions of the polymer chains. In contrast the compressibility decreases with the increasing concentration of this polymer. This study suggests there i

This study investigates the possibility of using waste plastic as one of the components of expired lead-acid batteries to produce lightweight concrete. Different percentages of lead-acid battery plastic were used in the production of lightweight concrete. The replacements were (70, 80 and 100%) by volume of the fine and coarse aggregate. Results demonstrated that a reduction of approximately 23.6% to 35% in the wet density was observed when replacement of 70% to 100% of the natural aggregate by lead-acid battery plastic. Also, the compressive strength decreased slightly with the increase in plastic content at different curing ages of 7, 28, 60, 90, 120 days. The lowest value of compressive strength was (20.7 MPa) for (wa

A green and low-cost method was used to prepare graphene oxide (GO) and reduced graphene oxide (rGO) by chemical exfoliation of graphite powder by modified Hummers method, followed by reduction using ascorbic acid. X-ray diffractometry (XRD) and field emission scanning electron microscopy (FE-SEM) were used to analyze the structure and morphology of the synthesized materials. Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy were used to identify the formation of the GO and rGO

A piezoelectric cantilever beam with a tip mass at its free end is a common energy harvester configuration. This article introduces a new principle of designing such a harvester that increases the generated power without changing the resonance frequency of the harvester: the attraction force between two permanent magnets is used to add stiffness to the system. This magnetic stiffening counters the effect of the tip mass on the efficient operation frequency. Five set-ups incorporating piezoelectric bimorph cantilevers of the same type in different mechanical configurations are compared theoretically and experimentally to investigate the feasibility of this principle: theoretical and experimental results show that magnetically stiffened harve

Abstract

The study aims to identify the degree of citizenship values practiced by Bisha University students and identify the impact of gender, college, and academic level, on the degree of the practice of University students for citizenship values. The researcher used the descriptive-analytical method including a questionnaire of (44) items. To process the data, the researcher applied the computational averages, standard deviations, percentages, and T-test. The questionnaire was implemented on a sample of (600) of the 2 and 8 levels during the second semester of the academic year (2020-2019) at Bisha University. The study findings revealed that the degree of the pra

This research aims at investigating pupils’ ability in using discourse markers which are identified in the English textbooks of secondary schools. Four texts are chosen from third intermediate class. The four texts are short stories of different topics.                                                  

        This research hypothesizes that there are no statistical significant differences among Iraqi intermediate pupils’ ability in using textual

An experimental study was conducted to determine the performance of a solar electric refrigeration system. The system contained flat photovoltaic solar panel which absorbs the solar energy and convert it to electrical energy, used to run the refrigeration cycle. Two refrigeration cycles with electrical solar panel were used over a period of 12 months, the first one with classical parts known in refrigeration cycle, while the second one introduced heat exchanger which improves the coefficient of performance by saving the consumed energy. The coefficient of performance of these refrigeration cycles with compressor efficiency 85% are 2.102 and 2.57 respectively. The overall efficiency of the two systems are 18.9% and 23.13%.

  The main aim of this research to study and recognize the specifications and main concepts of  (Fuzzy Logic) and its components and studying the practical experiments  of the (Fuzzy Logic)  techniques in the electrical engineering field through by using the (Fuzzy Logic) for controlling the three-phase AC induction motor by using (Matlab_ simulation_7) for modeling the system by using the computer

Westiellopsis prlifica was exposed to 1, 2, 3, 5, 7 and 10 ppm from both lead & Cadmium, in order to measure their capacity to remove these metals from the polluted aquatic environment and to study its ability to tolerant them. The algae were grown under optimum conditions.
Westiellopsis prlifica had the ability to remove the lead with percentages about 31.57, 54.42, 62.35, 61.8, 57.02 and 68.34% for the concentrations 1, 2, 3, 5, 7 and 10 ppm, respectively, but it was found that these percentages were be better in the last day of the experiment for some of the concentrations 1, 2 and 3 ppm, While the tolerant of it to lead was up to the concentration 10 ppm.
Westiellopsis prlifica appears ability to remove Cadmium with percent