ABSTRACT
This paper presents the measurement of the laser Threshold damage of an optical surface at different roughness coefficients. The study procedure is achieved
through the manufacturing of two types of parallel-sided borosilicate plate (Glass
Bk7, and SF13).
The Laser used is ND: YAG pulsed laser and the longitudinal mode TEM00 laser pulses with pulse width τ =30ns and wave length λ=1.064μm, the laser
beam is focused using F=30 mm lens. The concentrated laser beam is guided by a converging lens towards the optical surface of the parallel surface plate.
Finally, we obtained a graph of roughness coefficient is drawn in relation the optical Threshold Damage of the optical surface, Before and after processing
the optical surface. We were able to raise the threshold by about 15% after conducting thermal treatment of the optical surface.
The demand growing of energy is offset by the weakening of the generating capacity of
power due to the war conditions in Syria. As the windows are the means of optical
communication between inside and outside of the building, the source of the vent
ilation
and the natural lighting, thus having an important effect on the thermal performance of the
building, which affects the consumption of energy.
so the search relied on proposing alternatives for glass to test its thermal performance, the
choice of alternatives was based on the diversity between the values of solar radiation
permeability and the visual light in addition to enumeration of the layers, to which end the
computer simulation method was adopted and the results were compared to a model
Standard (single-transparent).
The results of the comparison showed that the amount of energy saving could be as high as
35% for the face of the sun-exposed facades directly. By reducing the permeability of the
total glass of solar radiation and increasing the permeability of the visible light to increase
the amount of natural illumination, plus the adoption of a Multi-layered glazing system ,
the study recommended that appropriate glass selection must be taken into account in the
early design phase
The research aims to evaluate the micro shear bond strength of the calcium silicate cement
(Biodentine) and the glass ionomer cement (GIC) to dentine. The study was performed using
upper or lower premolars, and samples were divided into six equal s
ubgroups according to
the time period (3 h, 1 day, 1 week, 2 weeks, 4 weeks, 8 weeks), in order to study changes in
the values of shear bond strength with time. The comparative study showed that the success
rate of adhesion in the Biodentine group was smaller than that in the GIC group for the tested
premolars after 3 hours and one day, whereas the success rate in the Biodentine group was
greater than that in the GIC group for the tested premolars after 8 weeks.
Results showed a positive correlation between the mean values of shear bond strengths and
the studied time in Biodentine group, which ranged from 1.49 ± 0.18 MPa at 3 hours to a
maximum value of 2.65 ± 0.26 MPa after 8 weeks. While there was a negative correlation
between the mean values and the studied time in the GIC group and values ranged from 3.02
± 0.13 MPa at 3 hours and 2.06 ± 0.09 MPa at 8 weeks.
The study showed the advantage of Biodentine compared with GIC in terms of
micro-bonding to dentine, which can have a clinically significant importance in preventing
the micro leakage and reducing bacterial contamination.
The aim of this study is improving the durability of precast products of Glass Fiber
Reinforced Concrete (GRC) and in the context of sustainability applications, reduction of
cement consumption and replacement of it with green materials. This study
has been done
to test the role of the natural pozzolan from Shihan Hill in As Suwayda as supplementary
cementing material by 10% -15% -20% - 25%, and to determine the effect of it on the
consistency and flexure strength over 180 days, as well as to test its role in improving the
micro-structure of the mixture by reducing the content of Ca(OH)2 and increasing C-S-H
& C-A-S-H gel, which were tested using X-Ray Diffraction (XRD) and Energy Dispersive
X-Ray (EDX) techniques, and as a result reduced the erosion of fibers as shown in images
by Scanning Electronic Electron Microscopy (SEM). Moreover the role of pozzolana has
been studied in controlling the degradation of the material over time which tested by
immersion in hot water 50° for 150 days and by drying – wetting cycles. Also the effect of
pozzolana on absorption, porosity and resistance of sulfates attacks was studied. The
results have shown that the used natural pozzolana has no negative effect on consistency or
mechanical properties, and it improved all the studied durability factors.
The use of double glass has spread largely to achieve thermal isolation and reduce the
consumption of energy in refrigerating in summer or heating in winter.
The manufacture of double glass has entered in Syria, and become very important
necessity
for achieving gain in consumption of energy, and specially in the drying process
of its before joining tow glasses together and making double panes.
The researcher has prepared mathematical model for heating exchanger which is used in
drying of panes by using Matlab program, and by this pattern the researcher has studied the
effect of different factors on design of the heating exchanger for finding the optimal design
which ensure reducing in using the energy in the drying process.
This study aimed to evaluate the fracture resistance of the E
glass Fiber Reinforced Composite when used to repair two different
kinds of dental porcelain.
In this research an experimental study has been carried out
to investigate the enhancement of Bosra Alsham´s soil (120 km
south Damascus) by using crushed glass wastes additives by using
experimental approach. The soil samples were taken from Bosr
a
(2m underground surface), which is classified as highly plastic
clayey soil CH according to unified classification.
An appropriate bond between glass‑ionomer and the superficial
resin materials is very important for the success of sandwich
technique. The aim of the present in vitro study was to evaluate the
effect of three surface treatments of conventional glass‑ionomer on
its shear bond strength to giomer
The Objective is to determined whether enamel conditioning with sodium
hypochlorite (5,25%) and EDTA prior to etching was increased shear
bond strength of orthodontic brackets bonded with resin – modified glass
ionomer. our sample consisted of 42 extracted human premolars were
randomly divided into 3 groups.
This study ains for the ability of using granite waste emerged by sawing granite in
Syria, which is considered as a negative effect on the environment , which pollutes the air ,
people, animal and planit. The chemical composition of granite waste w
as defined and it
was clear that it is same as the chemical composition of glass . so we did this work by
transforming the waste caused by granite sawmills to the glassy state.
The preparation for the glassy states were done py two methods , the first by adding
sand and sodium carbonate and second by adding borax and sodum cab ronate and the
heattreatment was done at (900-1000 c) . The assurance of getting the glassy state through
the XRD measure to the resulted samples was done . and the chemical composition of glass
resulted by alkaline melting way was identified , then doing the chemical analyses needed
to signify the percentage of oxides of the elements and in the second step of the worke ,
they have made tests on the resulted glass (its intensity, its resistance of acids and bases ).
The decrease of intensity was noticed by the increase of silica concentration , sodium
oxide and borates oxide , and it was noticed the increase of the resistance to the acids and
alkalis by the increase of silica concentration and sodium oxide , but through adding the
borates, the result was a glass less resistant to the acids and bases .
