Background: The demand for better esthetic during orthodontic treatment has increased nowadays, so orthodontists starting using esthetic arch wires, brackets and ligatures.Tooth colored brackets were introduced in different types of materials. Sapphire ceramic brackets are one type of esthetic brackets and their color stability remains the main concern for the clinicians and patients at the same time. The present study design to evaluate the effect of three different staining materials (pepsi, black tea and cigarette smoke) on the stainability of sapphire ceramic brackets bonded with three types of light cure orthodontic adhesives which include: Resilience, Enlight and Transbond. Materials and Methods: The sample consisted of three hundred sixty sapphire brackets. The brackets were divided according to bonding materials into three groups each group consist of one hundred twenty brackets, then each subgroup farther subdivided into four groups according to the material they were immersed (distilled water, black tea, Pepsi and cigarette smoke) with thirty brackets each, then Each group with ten brackets farther subdivided according to time interval of immersion in each media into three groups one day, seven days and fourteen days at 37°C in the incubator.A UV-Visible spectrophotometer (Shimadzu, UV -1800) was used to perform a light absorption test. Results: ANOVA and LSD post Hoc tests were used to identify the significant effects of the staining materials at a significance level P ≤ 0.05.It was found that the immersion time gradually influenced the color stability of the adhesive materials with sapphire brackets with the highest activity observed at fourteen days interval. The brackets bonded with Resilience light cure adhesive are the most type affected by staining materials, then followed by the brackets bonded with Transbond and finally the brackets bonded with Enlight light cure adhesive. For the staining materials it was found that the cigarette smoke is the most powerful staining material, followed by tea and finally pepsi. Conclusions: From the above result we can conclude that the type of adhesive must take in consideration when the esthetic brackets have been used.
Geophysical and petrographic evaluation of the earth’s subsurface is of vital concern, especially prior to geotechnical and hydrogeology works. Vertical Electrical Sounding (VES) of Ire-Akari Estate of Apatapiti Community in Akure South was carried out to assess the effects of the petrographic properties of charnockitic rocks on the geotechnical and hydrogeologic systems. The three curve types identified within the study area are AA, KH and HA, with a predominance of KH curve type, which suggests that the predominant geologic sequence comprising the topsoil has a clayey content alternating with laterite. This is underlain by weathered layer and fresh bedrock. Petrographic analyses revealed the presence of plagioclase (Albite-Anort
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This research studies Reinforcing and applied load of Wear Rate for Epoxy composites contains from epoxy resin (Ep) as a matrix material and reinforced by Gawain red wood flour , Russian white wood flour , glass powder and rock wool fibers , with volume fraction (20%) for all samples in lab conditions. by using the load (10,20 ,30 ,40) Newton of iron disc for testing time(10) minute, and the results have shown that the reinforcing of epoxy resin led to decrease wear rate for all samples except the hybrid composites reinforced earth glass powder , that the wear rate values decrease from (22×10-9g/cm) to (4×10-9g/cm) of composite material(Ep+R.W.F) and thus(Ep+W.W.F) at la
... Show MoreThis paper deals with the determination of stresses and deflections of clamped circular diaphragm strengthened by one or two ring-shaped concentric ribs, under uniform static and dynamic pressures. The simulation has been achieved by using the well-known engineering software finite element package MSC/NASTRAN.
As a design study, the effect of using a clamped ring, and the effect of using a ring-shaped rib on both surfaces of diaphragm instead of one, has been discussed in this work. To show the effectiveness of this study, results of this work have been compared with published data [1].
In the conclusion, the authors underline the validity of the&n
... Show MorePolymer concrete were prepared by mixing epoxy resin with sand particles in three different grain size (150-300) , (300-600 ) and (600- 1200) μm respectively. The percentage of epoxy was 15%, 20 %, 25% and 30% wt of the total weight. Compression strength and flexural strength tests were carried out for the prepared samples.
The percentages of epoxy resin at 20% wt and 25% wt showed best mechanical properties for all grain sizes. These percentages were adopted to fill the voids between particles sand have two different size ranges (150-600) μm and {(150-300) & (600-1200)} μm respectively to obtain more dense material. The results showed that the strength of polymer composite at 20% resin is higher than 25% resin.
Background: Fiber-optic endoscopy is an important
investigation of the large intestine, whether or not the
radiologist (barium enema) has discovered a lesion in
the bowel. Colonoscopy affords a unique opportunity
to direct visualization of entire colonic mucosa. At
the same time, the physician can obtain biopsy specimens, remove polyps, and decompress volvuli.
Most experienced endoscopists and well prepared
patients can reach the cecum in over 90% of patients.
If colonoscopy is properly performed, it has a low
risk of complications, such as perforation and bleeding.
Methods: A total of 70 consecutive patients admitted
to Endoscopy department at Al-Kindy Teaching hospital from September- 2008 to July-2009.
The 2011 Iraqi Measles Control Campaign had as its aim to improve immunization coverage among young adults' 17-24years and, in the longer term, prevention of measles epidemics. The aim of the study is estimation measles vaccination and revaccination efficacy by evaluate the seroprevalence of antibody and response to reimmunization in young adults. A previously vaccinated 189 young adult medical students were tested for measles specific IgG &IgM pre and post catch-up revaccination by using commercially available ELISA. To assess the seroprevalence of antibody response pre measles reimmunization in previously vaccinated young adults; 45 were found to be seronegative. To differentiate between primary and secondary vaccine failure, anti- mea
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Background: Fiber-optic endoscopy is an important
investigation of the large intestine, whether or not the
radiologist (barium enema) has discovered a lesion in
the bowel. Colonoscopy affords a unique opportunity
to direct visualization of entire colonic mucosa. At
the same time, the physician can obtain biopsy specimens, remove polyps, and decompress volvuli.
Most experienced endoscopists and well prepared
patients can reach the cecum in over 90% of patients.
If colonoscopy is properly performed, it has a low
risk of complications, such as perforation and bleeding.
Methods: A total of 70 consecutive patients admitted
to Endoscopy department at Al-Kindy Teaching hospital from September- 2008 to July-2009.
In this study, a qualitative seismic velocity interpretation is made up through using 2D-seismic reflection data on Luhais oil field in southern of Iraq which is situated at about 105 Km to the east from the Basra city. Luhais oil field was chosen to study the type and nature of the distribution of the seismic velocities of Nahr Umr and Zubair Formations in order to show its explorational importance, where these formations contain abundant quantities of hydrocarbons. Picking of the tops of Nahr Umr and Zubair was carried out from the synthetic seismogram which is calculated from sonic-logs and check shot of well Lu-2. Velocity model was obtained via using an implementation of Petrel program version, 2013 and was corrected according to to
... Show MoreIn this study, epoxy was used as a matrix for composite materials, with E-glass fiber, jute and PVC fiber which was woven roving fiber, as reinforcement with volume fraction (Vf= 30%). There are two of prepared types of epoxy non reinforced, epoxy reinforced with E-glass, jute and PVC fibers including study of mechanical tests (Impact test, Bending test) different temperature and thermal conductivity and calculating the temperatures coefficient at different temperature. Results show that elastic modulus at rate values decrease to the increase of temperature and the impact strength, impact energy and thermal conductivity increase with increase temperature.
Abstract
We can see the phenomena of small and medium-sized enterprises, by important and a new subject contemporary, thro related between important concept that develop and add. This research focused on the important concept of small and medium-sized enterprises, in public and privet sectors. small and medium-sized enterprises discrimination by large filer ratio in the especially at the first years when they started because of the limited managerial skills, financial recourses and marketing problems. On it they will creative new procedures. this research treatment the core issues about wakens local and international enterprises, so threat. the goals of this research are extended malty dimension concept o
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