This paper develops the work of Mary Florence et.al. on centralizer of semiprime semirings and presents reverse centralizer of semirings with several propositions and lemmas. Also introduces the notion of dependent element and free actions on semirings with some results of free action of centralizer and reverse centralizer on semiprime semirings and some another mappings.

The study aimed to identify the use of the electronic concept maps method in learning some of the skills of the floor exercises in the artistic gymnastics for third graders ,as well as to identify the best group between the two research groups (experimental And the officer to learn and retain some of the skills of the floor exercises in the artistic gymnastics of the research subject , and the experimental method was used and included the sample research on students of the collage of Physical Education and Sports Sciences/University of Baghdad, third grade, and has selected (10) Students for each group of The experimental and controlling groups randomly by lottery and after the completion of the period of implementation of the experiment wh

Mosquitoes play a serious role on public health transmitting several dangerous diseases such as malaria, filariasis and Encephalitis. So it consider as a vector diseases. Therefor it is important to control its spread using ecology friend’s factors like bacteria Bacillus thuringiensis var. israelensis and fungi Beauveria bassiana. Results revealed that the direct effect of Bacillus thuringiensis on the larvae led to the high mortality (100%) during 3 days while Beauveria bassiana have a cumulative effect on the Mosquito stage lifecycle; 7.3 X 104 more significant effect in the first day but there was no significant in the other days of treatment. In the end period of lifecycle there was no adult emergence and the adult which emergence up

Background: Heat-cured poly (methyl methacrylate) the principal material for the fabrication of denture base have a relatively poor mechanical properties. The aim of this study was to investigate the effect of glass flakes used as reinforcement on the surface hardness and surface roughness of the heat-processed acrylic resin material. Material and method: Glass flakes (product code: GF002) pretreated with silane coupling agent were added to Triplex® denture base powder using different concentrations. A total of 100 specimens of similar dimensions (65 x 10 x 2.5) mm were prepared, subdivided into 2 main groups of 50 specimens for each of the study tests. Ten specimens for the control group and 40 specimens for each of the experimental gro

Background: Polymethyl methacrylate (PMMA) is the most commonly used material in denture fabrication. The material is far from ideal in fulfilling the mechanical requirements. Midline fracture; poor thermal conductivity and water sorption, are common problem in this material. The purpose of this study was to evaluate the effect of addition of surface treated Aluminum oxide nano fillers on some properties of heat cured (PMMA). Materials and methods: In addition to controlled group of heat cured PMMA the silanized (Al2O3) nanoparticles was added to PMMA powder by weight in three different percentages 1wt%, 2wt% and 3wt%, mixed by probe ultra-sonication machine. 200 specimens were constructed and divided into 5 groups according to the test (e

Background: Polymethylmethacrylate (PMMA) has relatively unsatisfactory mechanical properties such as low flexural strength and impact strength also dimensional instability. Material and method: Zirconium silicate nanoparticles were coated with a layer of trimethoxysilylpropylmethacrylate (TMSPM) before sonication in monomer (MMA) with the percentages 1% and 1.5% by weight then mixed with powder using conventional procedure, (150) samples were prepared and divided into three groups, each group consisted of (50) samples, the first group prepared from PMMA without addition (control), another group with the addition of 1% wt Zrsio4 nanoparticles (experimental) and the third one with 1.5% wt Zrsio4 nanoparticles (experimental). Each group

The wild populations of the vinegar fly Drosophila melanogaster Meigen from two regions in Baghdad , Saidiya and Tuwaitha were selected for this study to investigating the frequency of the dominant lethality , this parameter was investigated through fecundity and egg hatchability rate which considered as main indicator for the presence of mutation . The results showed that fecundity rate in Saidiya increased with time , so the lowest rate was 65.5 eggs per female in November and the highest was 87.4 eggs in May , the same results was observed for Tuwaitha except a significantly decrease in fecundity rate that was observed in May which was 42.7 eggs , as well as another significant differences between the two regions was observed in March