The steady state laminar mixed convection and radiation through inclined rectangular duct with an interior circular tube is investigated numerically for a thermally and hydrodynamicaly fully developed flow. The two heat transfer mechanisms of convection and radiation are treated independently and simultaneously. The governing equations which used are continuity, momentum and energy equations. These equations are normalized and solved using the Vorticity-Stream function and the Body Fitted Coordinates (B.F.C) methods. The finite difference approach with the Line Successive Over-Relaxation (LSOR) method is used to obtain all the computational results. The (B.F.C) method is used to generate the grid of the problem. A computer program (Fortran 90) is built to calculate the steady state Nusselt number (Nu) for Aspect Ratio AR (0.55-1) and Geometry Ratio GR (0.1-0.9). The fluid Prandtl number is 0.7, Rayleigh number Ra = 400, Reynolds number Re = 100, Optical Thickness (0 ≤ t ≤ 10), Conduction- Radiation parameter (0 ≤ N ≤ 100) and Inclination angle λ = 45. For the range of parameters considered, results show that radiation enhance heat transfer. It is also indicated in the results that heat transfer from the surface of the circle exceeds that of the rectangular duct. Generally, Nu is increased with increasing GR, t and N but it decreased with AR increase. When the radiation effect added to the heat transfer mechanism, the heat transfer rate increased. This effect increased with increasing in GR and decreasing with AR. The increasing in radiation properties lead to increase the radiation effect. Tecplot 7 program was used to plot the curves which cleared these relations and isotherms and streamlines which illustrate the behavior of air through the channel and its variation with other parameters. A correlation equation is concluded to describe the radiation effect. Comparison of the results with the previous work shows a good agreement.
Linear discriminant analysis and logistic regression are the most widely used in multivariate statistical methods for analysis of data with categorical outcome variables .Both of them are appropriate for the development of linear classification models .linear discriminant analysis has been that the data of explanatory variables must be distributed multivariate normal distribution. While logistic regression no assumptions on the distribution of the explanatory data. Hence ,It is assumed that logistic regression is the more flexible and more robust method in case of violations of these assumptions.
In this paper we have been focus for the comparison between three forms for classification data belongs
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Background: Mouthwashes used widely as ancillary to mechanical oral hygiene methods. Little information provided about the effect of mouthwashes on ions released from orthodontic brackets. Therefore, the present study has been established to evaluate the effect of different mouthwashes on the corrosion resistance and the biocompatibility of two brands of brackets. Materials and Methods: Eighty premolar stainless steel brackets were used (40 brackets from each brand). They were subdivided into four subgroups (n=10) according to immersion media (deionized distilled water, Corsodyl, Listerine and Silca herb mouthwashes). Each bracket was stored in a closely packed glass tube filled with 15ml of the immersion media and incubated for 45 days at
... Show MoreNations are developed with education and knowledge that raise the status of society in its various segments, beyond that it leads to underdevelopment and deterioration in various sectors, whether economic, health, social, etc. If we considered the general name of The ministry of Education & Scientific Studies, then the second part seems to be not functioning, since scientific research has no material allocation and remains based on the material potential of the university professor. As for the first half of the topic, the reality of the situation reveals problems related to the Holy Trinity of Education which is (Professor - Student - the scientific method) where universities suffer at the present time from this problem, and
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Background: Acrylic resin polymer s used in prosthodontic treatment as a denture base material for several decades. Separation and debonding of artificial teeth from denture bases present a laboratory and clinical problem affect patient and dentist. The aim of this study is to evaluate the effect of oxygen plasma and argon plasma treatment of acrylic teeth and thermocycling on bonding strength to hot cured acrylic resin denture base material. Materials and Methods: Sixty denture teeth (right maxillary central incisor) are selected. The denture teeth are waxed onto the beveled surface of rectangular wax block according to Japanese standard for artificial teeth. The control group consisted of 20 denture teeth specimen without any treatment.
... Show MoreBackground: The most widely used material for fabrication of denture base is poly methyl methacrylate, despite its popularity, the main problems associated with it as a denture base material are poor strength particularly under fatigue failure inside the patient mouth, impact failure outside the patient mouth, which are the main causes for fracture of denture, several studies was done to increase mechanical properties of denture base. The present study was conducted to evaluate and compare the effect of addition single walled carbon nanotubes in different concentrations to polymethyl methacrylate on some mechanical properties (surface hardness, surface roughness, impact strength and transverse strength). Materials and methods: Forty eight
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When the financial resources of individuals and groups available, this will lead to increase the consumption ranges and sometimes reached to excessive especially to the categories that have little awareness about economic importance and its reflections. it seems that consumerism has increased in many countries including Iraq because of many factors, and the most important one is the availability of financial resources as a result of the increase in oil exports as well as the spread of consumption media department at various levels especially.
Development and progress of the fleet and the navy in Oman during
the reign of Sultan Said bin sultan from 1804 to 1856.
It had second level in Arab Gulf and Indian Ocean during the first half
of nineteenth century. The fleet of Oman in this time became after British
fleet.
Several reasons were behind the development of Omani fleet
- First : The aim of Sultan Said was to built a large navy yard in Arab Gulf
and Indian Ocean to encourage him -to made many ships factories.
- Second: Arab Gulf and Indian Ocean within the reign of Sultan Said
wittinsed the confilicts and wars between different forces it drived Sultan Said
to built agood and strong navy.
- Third The main aim of Oman during the reign of Sultan
Recent growth in transport and wireless communication technologies has aided the evolution of Intelligent Transportation Systems (ITS). The ITS is based on different types of transportation modes like road, rail, ocean and aviation. Vehicular ad hoc network (VANET) is a technology that considers moving vehicles as nodes in a network to create a wireless communication network. VANET has emerged as a resourceful approach to enhance the road safety. Road safety has become a critical issue in recent years. Emergency incidents such as accidents, heavy traffic and road damages are the main causes of the inefficiency of the traffic flow. These occurrences do not only create the congestion on the road but also increase the fuel consumption and p
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המחקר הזה עוסק באחד מהסופרים העבריים שנחשבו בעלי־השפעה בתהליך הספרות העברית החדשה על אף גילו הקצר ועל אף שהוא השאיר עזבון ספרותי מועט, אך עם זה דמותו עולה לענינו גם מתוך כתביו המעטים כאילו הם טבועים בחותם, הסופר הזה הוא מרדכי זאב פיארברג.
במחקר זה טיפלנו בחייו של המספר הזה בקיצור וגם ביצירותיו באופן כללי, ובסימנים המאפינים את גיבוריו, ובמיוחד גיבורו של הסיפור "
... Show MoreVatan ve hürriyet aşkının ilk ve en Kuvvetli örneklerinden Türkmen topraklarında yetişen yüzlerce Şairlerden biri Hıdır Lütfü’dür. Düşmana yar, öz evladına ağyar, yumuşak tabiatlı, yardımı ve milletini seven bir insandır. Şairin duygusu her dem yükseklere yücelirdi. O bilgili bir şair olduğu için şiirinde türlü türlü bilgi ile ögütleri arkasında bırakmamış onun duygusu bir bulak gibi her dem durmadan coşardı.
Onun en çok sevdiği varlıklar yurdu ile ulusuydı, ve tek acısı onların ilerleme ile yükselemesi içın bir haykırıydı.
Şair her zaman yurdunun ufukunda dolaşıp ulusunun bugünkü ve geleck torunları için yanıklı duyguları ile bir yol gosterıci gibi olmuştur.