n Segmented Optical Telescope (NGST) with hexagonal segment of spherical primary mirror can provide a 3 arc minutes field of view. Extremely Large Telescopes (ELT) in the 100m dimension would have such unprecedented scientific effectiveness that their construction would constitute a milestone comparable to that of the invention of the telescope itself and provide a truly revolutionary insight into the universe. The scientific case and the conceptual feasibility of giant filled aperture telescopes was our interested. Investigating the requirements of these imply for possible technical options in the case of a 100m telescope. For this telescope the considerable interest is the correction of the optical aberrations for the coming wavefront, the modified Zernike polynomials for hexagonal aperture were used to describe the wavefront aberrations and to predict the initial state for the adaptive optics corrections.
This research is concerned with the re-analysis of optical data (the imaginary part of the dielectric function as a function of photon energy E) of a-Si:H films prepared by Jackson et al. and Ferlauto et al. through using nonlinear regression fitting we estimated the optical energy gap and the deviation from the Tauc model by considering the parameter of energy photon-dependence of the momentum matrix element of the p as a free parameter by assuming that density of states distribution to be a square root function. It is observed for films prepared by Jackson et al. that the value of the parameter p for the photon energy range is is close to the value assumed by the Cody model and the optical gap energy is which is also close to the value
... Show MoreThe lower respiratory tract of sheep was studied to determine the torsion and branching of the bronchial tree. The respiratory system of ruminants and all living organisms is one of the most important organs in the body that controls the amount of gas exchange between the heart and lungs through the airways, it is clear that in sheep it consists of a narrow bronchial tube that reaches the extent of lung tissue repercussions. He used silicon, water, acid, and at room temperature, and the substance was injected with an injection gun through the trachea and was pushed gently to spread and distribute in all parts of the lungs with moderate manual pressure. The results showed that the mold shape in the lung and the bronchial branches of
... Show MoreBackground: Mini implant stability is primarily related to local bone density; no studies have evaluated bone density related to mini implant placement for orthodontic anchorage between different age groups in the maxilla and the mandible. The present research aims to evaluate side, gender, age, and regional differences in bone density of the alveolar bone at various orthodontic implant sites. Materials and method: Fifty three individuals who were divided into two groups according to their age into: group I (ages 16-20 years) and group II (ages 21-29 years) had subjected to clinical examination, then 64-multislice computed tomography scan data were evaluated and bone density was measured in Hounsfield unit at 102 points (51 in the maxilla
... Show MoreAbstract:
The main objective of the research is to build an optimal investment portfolio of stocks’ listed at the Iraqi Stock Exchange after employing the multi-objective genetic algorithm within the period of time between 1/1/2006 and 1/6/2018 in the light of closing prices (43) companies after the completion of their data and met the conditions of the inspection, as the literature review has supported the diagnosis of the knowledge gap and the identification of deficiencies in the level of experimentation was the current direction of research was to reflect the aspects of the unseen and untreated by other researchers in particular, the missing data and non-reversed pieces the reality of trading at the level of compani
... Show MoreBackground: The anterior loop of mental nerve is commonly described as that part of the neurovascular bundle that transverses anterior and inferior to the mental foramen only to loop back to exit the mental foramen. The aim of the study is to evaluate the incidence and extension of anterior loop of mental nerve by using digital panoramic imaging system to avoid nerve damage during different surgical procedures in dentistry. Materials and Method: Panoramic image was taken for all 400 patients and stored in the computer. Then Horizontal and Vertical for the anterior loop extension when exist was measured and recorded in a special case sheet prepared for each subject. Results: Results indicated that out of 400 patients there were only 25 pat
... Show MoreThis research aims to study the radiation concentration distribution of the old District of Najaf (Iraq), where 15 samples were taken from featured sites in the District, which represents archaeological, religious, and heritage sites. Track detector CR-39 was used to calculate the concentration of three different soil weights for each sample site after being exposed for a month. Geographical information systems (GIS) were used to distribute the radioactive concentration on the sites of the samples, where two interpolation methods, namely the inverse distance weight method (IDW) and the triangle irregular network method (NIT), to study the distribution of the radioactivity concentration. The study showed that the western part of the district
... Show MoreThe problem of present study is determined by answering the following questions:
1) What is the effect of using the oral open- ended questions on Students' achievement in the third-stage of Arabic department in the college of Education? 2) What is the effect of the oral open-ended questions on developing the creative thinking of students in
... Show MoreIn this paper, experimental study has been done for temperature distribution in space conditioned with Ventilation Hollow Core Slab (TermoDeck) system. The experiments were carried out on a model room with dimensions of (1m 1.2m 1m) that was built according to a suitable scale factor of (1/4). The temperature distributions was measured by 59 thermocouples fixed in several locations in the test room. Two cases were considered in this work, the first one during unoccupied period at night time (without external load) and the other at day period with external load of 800W/m2 according to solar heat gain calculations during summer season in Iraq. All results confirm the use of TermoDeck system for ventilation and cooling/heat
... Show MoreThis paper describes a new finishing process using magnetic abrasives were newly made to finish effectively brass plate that is very difficult to be polished by the conventional machining processes. Taguchi experimental design method was adopted for evaluating the effect of the process parameters on the improvement of the surface roughness and hardness by the magnetic abrasive polishing. The process parameters are: the applied current to the inductor, the working gap between the workpiece and the inductor, the rotational speed and the volume of powder. The analysis of variance(ANOVA) was analyzed using statistical software to identify the optimal conditions for better surface roughness and hardness. Regressions models based on statistical m
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