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Register a new userمنهجيات التصميم و التصنيع للنظم البصرية الخاضعة لإجهادات استاتيكية ناجمة عن المثبتات المعدنية و تغيرات درجة الحرارة
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ضمن إطار السعي لتوسيع مفهوم التصميم البصري ليشمل التصميم و التصنيع البصري الميكانيكي و ما يترتب من أثر للإجهادات الاستاتيكية على العناصر البصرية نتيجة شد المثبتات المعدنية و معرفة الأداء البصري الناجم، قمنا بدراسة مرجعية تبين أثر الإجهادات الاستاتيكية على العناصر البصرية نتيجة التماسات المعدنية و الحرارة و اللواصق ، كما قمنا باستخدام نمذجة عددية بطريقة العناصر المنتهية للتنبؤ بالأداء البصري للنظم البصرية.
In the frame of expanding the concept of optical design to include the designing and manufacturing of opt-mechanical systems, and the effect of static stresses on optical elements due to fastening of metal retainers and the resulting optical performance, a literature review was carried out to show the effect of static stresses on optical elements due to metallic contacts, temperature and adhesives. Numerical method of finite elements to predict the visual performance of optical systems had been performed.
References used
Robert E. Fischer, Biljana Tadic-Galeb, & Paul R. Yoder, Optical System Design, 2nd Edition, SPIE Press, McGraw Hill, NY, 2008
KEITH J.KASUNIC ,Optomechanical systems engineering [M], Published by John Wiley & Sons, Inc., Hoboken, New Jersey, 2015
K. Schwertz, H. Burge, Field Guide to Optomechanical Design and Analysis[M] , Bellingham: SPIE Press ,2012
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It is very important to the design and development of
natural isolating materials Which are used in the cover-up of solid waste landfill, clay soils or mixtures of these soils and some
additions used as an impermeable liner for construction of soli
d
waste landfill, The permeability coefficient of the materials used in the impermeable system is the most important factors to prevent water leakage into the body of landfill site and to prevent the Leachate of leak into groundwater and soil surrounding the landfillsites.
In this research has been the development and design
Oedometer cell to study volumetric distortions occurring in these
soils as a result of exposure of these soils to climatic conditions
during the implementation of impermeable layer or after
implementation due to rising temperatures in landfill because of
biological interactions taking place at these landfill.
It has been modified and the development of Oedometer
cell to become a thermal cell So that it can control the degree of
heat applied to the sample in the ring of device and then measure the volumetric changes in the sample, Oedometer cell has been linked to the permeability test system with variable head to measure the permeability of the testing sample, It was connected with the digital control , measuring and showing system for temperature and load and displacement.
Due to the importance of climate changes and their strong and increasing influences
on different human and ecological systems, It is necessary to study and understand these
changes. This research aims to determine the direction and magnitude of the
change in
temperatures and rainfall trend during 1978-2011 in Latakia, Kasaab and Slenfeh. The
study has been done through the analysis of annual, seasonal, and monthly rainfall amount
and temperature average, which showed a significant increasing in the average annual
temperature in the three regions and significant seasonally increasing except for Winter in
Latakia and Slenfeh, Autumn in Latakia. But the annual rainfall changes were nonsignificant,
while seasonally rainfall increased significantly in Slenfeh Winter and
decreased in Kasaab Winter. After dividing the entire study duration into two equal periods
1978-1995, 1995-2011 and comparing the second period with the first one, we found a
significant increasing in the average annual temperature in the three regions,
non- significant in the annual and seasonal rainfall changes. The highest significant in
seasonal temperature in Latakia, Kasaab and Slenfeh reached +1.5, +2.9, +1.8 during
September, August، and May respectively. While the annual drought showed increased
trend in Latakia and kasaab and decreased one in Slenfeh.
The retroreflection phenomenon takes place in all optical and optoelectronical
devices and systems that use optical detectors, mirrors, CCD
cameras, filters, or glasses in the focal point and in the optical measurement
instruments, in general, pro
vided that some of their optical components are
retroreflective to light even for small apertures.
The article studies a precise method to measure the retroreflection index of
optical, opto-electronical systems, and treats the optical retroreflections which
are used in applied research of light with various lasers such as: Nd:YAG first
and second harmonics, He-Ne, and laser diodes.
We have studies the conformity of our results to the theory of
retroreflectors. We found that the retroreflection coefficient depends on laser
wavelength. The article points out that at 532nm laser wavelength the
retroreflection is greater than at 1064nm laser wavelength.
The results of this paper can be used in applied research, and led to
description of a mathematical relationship between the retroreflection index
and laser wavelength.
This research aimed at studying the impact of firm characteristics on the level of
social responsibility disclosure by firms subject to the rules of The Syrian Commission on
Financial Markets and Securities. The research was applied on 38 companies
for which
data was available from 2007-2013.
To measure the level of firms’ social responsibility disclosure, the dependent
variable, an index was built based on the KLD index. Firm characteristics, the independent
variables, that were examined are: profitability, financial leverage, age, industrial sector,
size, managerial ownership, institutional ownership and foreign ownership. Data were
hand collected from the annual reports of the firms in question and analyzed following the
random effect model, of the panel data models. The results indicate that the size of the firm
and its profitability are positively linked to its social responsibility disclosure. No effect
however was detected for the age of the firm, the industrial sector, and the ownership
structure. The results also reveal that the Syrian crisis had a positive effect on the level of
social responsibility disclosure, as these firms increased disclosure of social responsibility
related to community service, particularly those related to the support of martyrs families
and war casualities.
This study was conducted at the laboratories of Food Science Department,
Faculty of Agriculture, Damascus University to assess the indicators
determining the optimum time and final critical temperature required for
forming the meat emulsions.
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