A simulated ion/electron optical transport and focusing system has been put forward to
be mounted on high voltage transmission electron microscope for in situ investigations.
The suggested system consists of three axially symmetric electrostatic lenses namely an
einzel lens, an accelerating immersion lens, and a decelerating immersion lens, in addition
to an electrostatic quadrupole doublet lens placed on the image side. The electrodes
profile of these lenses is determined from the proposed axial field distributions. The
optical properties of the whole system have been computed together with the trajectory of
the accelerated charged-particles beam along the optical axis of the system. The computed
dimensions of the final image have been found to be electron-optically acceptable
Background: White spot lesions are esthetic problems caused by subsurface enamel demineralization that seen as white opacity. Aim of the study: This study aimed to evaluate and to compare the color change after the treatment of the white spot lesions with resin nϔtrton and micro abrasion. Materials and Methods: rtϔ white spot lesions were generated on 48 premolar teeth by the use of a demineralization solution. The teeth were randomly divided using the Diagnodent into three study groups (16 teeth for each group) depending on the depth of the induced lesions: outer enamel, inner enamel and outer dentine. Then each group was fatherly subdivided into two groups (8 teeth for each group) the ϔrst group was treated wit
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Purpose of this study is to investigate the relationship between Advertising Appeals, Attitudes toward Advertising, and Consumer Buying Behavior for Smart Phone The study was carried out on the students of Middle East University (MEU) In Amman- Jordan. A measurement scales with acceptable reliability and validity is developed to capture the dimensions of study variables. Four hypotheses were tested using Statistical package (SPSS-17). A two-step detailed statistical analysis of data was involved. First, descriptive statistics was performed to understand the underlying components of study variables; second, regression analysis and Path analysis using AMOS 7 were performed t
... Show MoreThis study aimed to assess orthodontic postgraduate students’ use of social media during the COVID-19 lockdown. Ninety-four postgraduate students (67 master’s students and 27 doctoral students) were enrolled in the study and asked to fill in an online questionnaire by answering questions regarding their use of social media during the COVID-19 lockdown. The frequency distributions and percentages were calculated using SPSS software. The results showed that 99% of the students used social media. The most frequently used type of social media was Facebook, 94%, followed by YouTube, 78%, and Instagram, 65%, while Twitter and Linkedin were used less, and no one used Blogger. About 63% of the students used elements of social media to l
... Show MorePremature degradation is the problem of maxillofacial silicones, significantly affected by ultraviolet exposure, contributing to silicones photodegradation. Degradation necessitates frequent replacement of prostheses that increase the total cost of rehabilitation.
This study evaluated the effect of bisoctrizole on the ultraviolet absorption properties of silicone material and the stability of this absorption over time. Also, the bisoctrizole effect on the surface roughness of silicone was evaluated.
Hydrogen and nanocarbon were produced by the catalytic decomposition of electrocracking gas obtained by the pyrolysis of liquid organic waste via electric arc discharge. The GIAP-16 (NiO-Al2O3) industrial catalyst was used to reduce the maximum decomposition temperature to 700 °C. In a fixed-bed reactor, under atmospheric pressure, reasonable amounts of high-purity hydrogen were produced, accompanied by deposits of nanocarbon by-product. The NiO-Al2O3 catalyst showed excellent catalytic activity. X-ray powder diffraction analysis of the NiO-Al2O3 composite revealed the presence of cubic NiO and rhombohedral Al2O3, which were chemically stable. However, above 500 °C, NiAl2O4 began to appear. The specific surface area of the catalyst was de
... Show MoreThe purpose of the study is to analyze the extent of the impact of liquidity as an independent variable on profitability as an intermediate variable and the value of banks listed in the Iraq Stock Exchange as a dependent variable, as the research problem is summarized by the fact that most banks focus on profitability as a phased goal without focusing on maximizing its value as a strategic goal by enhancing the wealth of owners and shareholders. On the long term, the research community is represented by the banks listed on the Iraq Stock Exchange, while the research sample was deliberately chosen, which included three private banks such as Baghdad Commercial Bank, the Iraqi Commercial Bank and the Iraqi Investment Bank, an
... Show MoreThere is no doubt that Agricultural Policy is the main responsible for the degrading in Agricultural sector in Iraq during the period 2003-2013, and that was very clear from magnitude of indicators because of little sharing of each of agricultural product in GDP because it was (9.38%) in average during the study period and the annual changing of it was negative (-5.82%), and there is increasing in deficit of trade balance in Agriculture during the study period about (4185.73) million US$, and the percentage of agricultural exports from total exports was (0.14%) in average only. The foreign trade policy in Agricultural products also cannot determine map of Revealed Comparative Advantage (RCA) of Agricultural products and crops. The study sh
... Show MoreThe enhancement of the thermal and thermo-hydraulic performance of a semi-circular solar air collector (SCSAC) is numerically investigated using porous semi-circular obstacles made of metal foam with and without longitudinal porous Y-shaped fins. Two 10 and 40 PPI porous material samples are examined. Three-dimensional models are built to simulate the performance of SCSAC: model (I) with clear air passage; model (II) with only metal foam obstacles, and model (III) with metal foam obstacles as well as porous Y-fins. COMSOL Multiphysics software version 6.2 based on finite element methodology is employed. A conjugate heat transfer with a (k-ε) turbulence model is selected to simulate both heat transfer and fluid flow across the entir
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