Bragg Reflectors consist of periodic dielectric layers having an optical path length of quarter wavelength for each layer giving them important properties and makes them suitable for optoelectronics applications. The reflectivity can be increased by increasing the number of layers of the mirror to get the required value. For example for an 8 layers Bragg mirror (two layers for each dielectric pair), the contrast of the refractive index has to be equal to 0.275 for reaching reflectivity > 99%. Doubling the number of layers results in a reflectivity of 99.99%. The high reflectivity is purely caused by multiple-interference effects. It can be analyzed by using different matrix methods such as the transfer matrix method (TMM) which is the simplest method to study the characteristic of devices with different alternating layers.
ان الهدف من البحث الحالي هو تقويم كتاب الفيزياء للصف الرابع العلمي وفق معايير تصميم وانتاج الانفوجرافيك ومن اجل تحقيق هذا الهدف تم اختيار المنهج الوصفي(تحليل المحتوى) وحدد مجتمع البحث بكتاب الفيزياء للمرحلة الاعدادية الرابع العلمي, المقررة للعام الدراسي 2020-2019 ـ اما عينة البحث فكانت جميع الرسوم والاشكال والمخططات المتضمنة في هذا الكتاب. تم اعداد اداة التحليل المتمثلة بقائمة معايير تصميم وانتاج الانفوجرافيك
... Show Moreان الهدف من هذا البحث هو تحليل كتاب الفيزياء للصف الخامس العلمي للمرحلة الاعدادية في ضوء معايير تصميم وانتاج الانفوجرافيك. ويتم التحقق من هدف البحث من خلال الاجابة عن الاسئلة الاتية: ما هي المعايير التي يمكن في ضوئها تقويم كتاب الفيزياءلصف الخامس العلمي؟ ما النسبة الواجب توافرها لمعايير تصميم وانتاج الانفوجرافيك في كتاب الفيزياء لصف الخامس العلمي؟ ما مدى توفر معايير تصميم وانتاج الانفوجرافيك في كتاب الفيزي
... Show MoreThis study investigated a novel application of forward osmosis (FO) for oilfield produced water treatment from the East Baghdad oilfield affiliated to the Midland Oil Company (Iraq). FO is a part of a zero liquid discharge system that consists of oil skimming, coagulation/flocculation, forward osmosis, and crystallization. Treatment of oilfield produced water requires systems that use a sustainable driving force to treat high-ionic-strength wastewater and have the ability to separate a wide range of contaminants. The laboratory-scale system was used to evaluate the performance of a cellulose triacetate hollow fiber CTA-HF membrane for the FO process. In this work, sodium chloride solution was used as a feed solution (FS) with a concentratio
... Show MoreThis study included isolation and characterization of extremely halophilic bacteria from Al-Massab Al-Aam region in South of Iraq Fifty isolates were identified by using numerical taxonomy 40 strains belonged to the genus Halobacterium which inclucted Hb. halobium Hb. cutirubrum Hb. salinarium Hb. saccharovorum Hb. valismortis and Hb. volcanii. Ten strains belonged to the genus Halococcus which included Hc. morrhuae Hc. saccharolyticus. Growth curves were sensitive mutants determined for wild type and salt Generation time in logarthmic phase was measured and found to be (10.37 2hr 7 0.59) for Hb. salinarium / 18 (6.490 hr 0.24) for Hb. cutirubrum / 32, (6.700 hr + 0.488) for Hb. valismortis / 20, (11.243 hr + 0.96) for Hb. volcanii / 7. (7
... Show MoreThe research aims to identify: 1-Designing a test to measure the movement compatibility of the eye and the leg for the students of the Faculty of Physical Education and Sports Sciences, Samarra University. 2-Codification (setting scores and standard levels) for the results of the motor compatibility test for the eye and the leg for students of the Faculty of Physical Education and Sports Sciences, Samarra University. The researchers reached the some following conclusions: 1-A test to measure the movement compatibility of the eye and the leg for the students of the Faculty of Physical Education and Sports Sciences. 2-There is a discrepancy in the standard levels of the research sample.
In this study, the effect of design parameters such as pipe diameter, pipe wall thickness, pipe material and the effect of fluid velocity on the natural frequency of fluid-structure interaction in straight pipe conveying fully developed turbulent flow were investigate numerically,analytically and experimentally. Also the effect of support conditions, simply-simply and clamped-clamped was investigated. Experimentally, pipe vibrations were characterized by accelerometer mounted on the pipe wall. The natural frequencies of vibration were analyzed by using Fast Fourier Transformer (FFT). Five test sections of two different pipe diameters of 76.2
mm and 50.8 mm with two pipe thicknesses of 3.7 mm and 2.4 mm and two pipe materials,stainles
The influence of anodization time with the electrochemical cell design on the fabrication process of porous silicon (PS) nanostructures based on two electrochemical anodization cells (designed single tank cell and double tank cell) with two anodization times (10 and 30 minutes) was studied. Atomic force Microscopy (AFM) characterization had revealed three types of pores, mesopores, mesopore fill of mesopores, and macropore fill of mesopores were obtained from designed single tank cell with (10 and 30 minutes) of anodization time, whilst for double tank cell has not revealed precise information about the size and type of pores. Pores formation have been further approved by current-voltage (I-V) measurement and pho
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Seeking pharmacist advice about minor ailments is a common practice among Iraqi patients because such advice is free and quick. Unfortunately, the assessment and management of minor ailments by Iraqi pharmacists were inappropriate. Therefore, this study aimed to develop a model for a mobile application that can assist community pharmacists in the diagnosis and management of minor ailments.
The scientific content of the application was based on the information in the symptoms in the pharmacy and British Nati
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Each era has advantages in terms of innovation and development in form, technology, style, and design in ceramic vessels, both at the level of functional and aesthetic performance, so this study aimed to demonstrate the importance of geometrical foundations in the design structure of contemporary ceramic vessels, and also to reveal the constructive skills in The structure of the ceramic figure.
The researchers used the descriptive analytical approach to suit the nature of the study, and they described and analyzed the ceramic works in terms of geometric shape systems, elements and foundations of design in construction, formal diversity in the general design of ceramic vessels, and references and sources of artwork. In addition to th
Since the invention of the automobile, no aspect of American life, including crime and its control, has remained untouched by this far-reaching innovation in transportation. Vehicular "hot pursuit"-when suspects in motor vehicles use excessive speed in attempting to elude the police. Unfortunately, accounts of wild chases across crowded inner city streets, through tree-lined suburban boulevards, and over remote country roads are very real and not merely fictional material created for entertaining television and motion picture audiences. The specter of "hot pursuit," complete with screaming sirens and red or blue flashing lights, has become a recurring fact of modem life.1 So, too, are the mishaps involving police vehicles or the vehicles pu
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