The ceramic compound Mg1-xSixAl2O4 (x= 0, 0.1, 0.2, 0.3, 0.4) was prepared from nano powder of Al2O3 and MgO doped with Nano powder of SiO2 at different molar ratios. The specimens were prepared by standard chemical solid reaction technique and sintered at 1450 oC. Structure of the specimens was analyzed by using X-ray diffraction (XRD). The X-ray patterns of the specimens showed the formation of pure simple cubic spinel structure MgAl2O4 phase with space group of ̅ . The average grain size and surface topology were studied by atomic force microscopy. The results showed that the average grain size was about 73-90 nm. The DC electrical properties of the specimen were measured. The apparent density was found to increase and the porosity and water absorption were found to decrease with increase of Si addition. Mechanical properties were characterized by Vicker’s micro hardness and Brazilian fracture test to measure the fracture toughness of the samples. The micro hardness decreased with Si addition increase. Fracture toughness increased with the increase in Si addition.
The research includes studying melodic and rhythmic properties, In the audio format for Iraqi musicians. The audio form is one of the important methodological forms in Arab music in general and Iraqi music in particular. It showcases its characteristics, features, internal form, and how important it is in Iraqi music.
Addressed ((the systematic framework)) presenting the research problem and the need for it. Its importance, purpose and limitations of its research, which included music ((Khaled Muhammad Ali)) as a human limit to reveal its characteristics in the composition of the audio form. And define the terms included in the research. And included ((theoretical framework)) on three topics .. The first: composing. The second
Mortar of ordinary Portland cement was blended with cockles shell
powder at different weight ratios to investigate the effect of powder
admixture on their strength and thermal conductivity. Results showed
that addition of cockles shell powder at 50% of mortar weight
improves hardness and compressive strength notably and reduces the
thermal conductivity of the end product. Results suggest the
possibility to incorporate cockles shell powders as constituents in
cement mortars for construction and plastering applications.
Surface water samples from different locations within Tigris River's boundaries in Baghdad city have been analyzed for drinking purposes. Correlation coefficients among different parameters were determined. An attempt has been made to develop linear regression equations to predict the concentration of water quality constituents having significant correlation coefficients with electrical conductivity (EC). This study aims to find five regression models produced and validated using electrical conductivity as a predictor to predict total hardness (TH), calcium (Ca), chloride (Cl), sulfate (SO4), and total dissolved solids (TDS). The five models showed good/excellent prediction ability of the parameters mentioned
... Show MoreObjective: The aim of the research is to prepare skilled mental exercises according to spatial and temporal perceptions and the awareness of the strength of young pole-vaulters, and to recognize the impact of these exercises on improving the indicators of electrical activity of working muscles and some special physical abilities and accomplishing this effectiveness Research methodology: The researcher used the experimental curriculum (one experimental group), and included the sample of research on (5) two joint jumpers in the Iraqi club championship, all from the center of talent in athletics, the sample is trained on the same curriculum prepared by the coach himself but accompanied by a mental training approach that Prepared by the
... Show MoreGlobal warming has a serious impact on the survival of organisms. Very few studies have considered the effect of global warming as a mathematical model. The effect of global warming on the carrying capacity of prey and predators has not been studied before. In this article, an ecological model describing the relationship between prey and predator and the effect of global warming on the carrying capacity of prey was studied. Moreover, the wind speed was considered an influencing factor in the predation process after developing the function that describes it. From a biological perspective, the nonnegativity and uniform bounded of all solutions for the model are proven. The existence of equilibria for the model and its local stability is inves
... Show MorePMMA films of different thickness (0.006, 0.0105, 0.0206, 0.0385 and 0.056cm) were synthesized by casting process. The temperature and frequency dependence of dielectric constant and AC electrical conductivity measurements at various frequencies (10kHz-10MHz) and temperatures (293-373K) were carried out. Few anomalies in dielectric studies were observed near 313 and 373 K respectively. These points were related to glass transitions temperature. The variation of activation energy and conduction behavior was studied .From the AC conduction studies, it is confirmed that the mechanism responsible for the conduction process is hopping of carriers. The variations of the dielectric constant and loss as function of frequency at different tempera
... Show MorePure Polyaniline salt, and protonation PANI by H2SO4 were synthesized by electro-chemical oxidative polymerization of aniline with acidity of H2SO4. The solution was prepared in reaction temperature equal 291 K and the acidity of aqueous solution was 1 molarities. The prepared polyaniline was characterized by FT-IR, the result indicate that the intensity is increase with increasing of applied voltage. The dc conductivity has been measured for bulk polyaniline pure and doped in the form of compressed pellet with evaporated Ohmic Al electrodes in temperature range (303-423) K. The Eav energy of the thermal rate process of the electrical conductivity was determined. The results indicate that the dc conductivity of doped samples are two or t
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