The pumping station became widely used in many fields. Free surface vortices at intakes of pumps are not favorable. It may cause noise, excessive vibration, damage to the pumping structure, reduction in efficiency and flow for hydro-turbines, etc. One of the important problems encountered during the pump intake design is the depth of submergence and other design parameters to avoid strong free-surface vortices formation. This study aims to compute the critical submergence depth with some geometrical and hydraulic limitations by using Computational Fluid Dynamic (CFD) package. The mathematical model was validated with a laboratory model that had been conducted. The model of three intake pipes was investigated under five different submergence depth (S), three different spaces between intake pipes (b), and five different suction velocities (v). The results showed the best operation cases when the space between intake pipes (b) equal to 4D, the submergence depth of water is equal or greater than 1.25 from the bell mouth diameter of intake pipe (D), and the suction velocity less than 2 m/s. The worst case was when the space between the suction pipe (b) was (2D), in this case, the vortex appeared at submergence depth (S/D = 2) with suction velocity 3 m/s.
This study aims to examine the sources of organizational power prevailing among the academic leaders at the University of Tabuk from the faculty members’ viewpoint. The purposes behind such an aim are: to reveal the level of administrative and technical institutional creativity, the nature of the relationship between the reality of organizational power and the level of institutional creativity, and to disclose statistically the significant differences between the averages of faculty members’ responses attributed to the demographic variables (gender, years of experience, academic degree). The study used the descriptive approach, both survey and correlational. A questionnaire was used to collect data from a simple random sample o
... Show MoreThe doping process with materials related to carbon has become a newly emerged approach for achieving an improvement in different physical properties for the obtained doped films. Thin films of CuPc: C60 with doping ratio of (100:1) were spin-coated onto pre-cleaned glass substrates at room temperature. The prepared films were annealed at different temperatures of (373, 423 and 473) K. The structural studies, using a specific diffractometry of annealed and as deposited samples showed a polymorphism structure and dominated by CuPc with preferential orientation of the plane (100) of (2θ = 7) except at temperature of 423K which indicated a small peak around (2θ = 3
Background: Incorporation of chemical additives has long been a technique used to improve properties of the gypsum products. The purpose of this work was to study the effects of adding a combination of gum Arabic and calcium hydroxide to a type III dental stone and type IV improved die stone with different proportion. The effect on water/powder ratio, and surface hardness was determined. Material and method: Both material stone and die stone were blended with two proportion of additives so that each material was mixed twice but with different proportion of gum Arabic (0.1% and 0.2%) and calcium hydroxide (0.5 % and 0.3%). Data for hardness were subjected to two-way analysis of variance. Results: The results revealed that the chemical additi
... Show MoreObjectives: This study aimed to evaluate and compare the effect of plasma treatment versus conventional treatment on the micro shear bond strength (μSBS), surface roughness, and wettability of three different CAD/CAM materials. Materials and methods: Sixty cylindrical specimens (5 mm diameter ×3 mm height) were prepared from three different CAD/CAM materials: Group A: Zirconia, Group B: Lithium disilicate, and Group C: Resin nano-ceramic. Each group was subdivided into two subgroups according to surface treatment used: Subgroup I: Conventional treatment, zirconia was sandblasted with Al2O3, while lithium disilicate and resin nano-ceramic were etched with hydrofluoric acid. Subgroup II: Plasma treatment, the surface of each material was tr
... Show MoreThe expression is a prominent feature of the Arabic language, but it is one of the characteristics that are inseparable from it. The expressive aspects of each other.
The issue of Arab differences and their impact on the divergence of meaning is one of the issues that have preoccupied the minds of the Arabic language owners and their views went to various doctrines. Introduction: (Whenever I finished a question concluded with a verse related to any download, and followed by the need for expressing, interpretation and interpretation) I found him in some of the Aarabip more than the face of some of the vocabulary raised and erected and a jar, when the verses of the Koran, resulting in a research lies between Grammar and the Koran under
The shift that caused the fading art schools and the brightness of the other, which dictate the work of art based surface and defect lasting regeneration led the researcher to stop at the color of his study, as an element of fixed and mobile at the same time, hard as a lieutenant of the painting plastic and brick construction that supports a painting, The variable that follows the doctrine of the artist and the philosophy of the community, because of the extrapolation of his biography, especially in modern art and beyond is clear that compose a variety of ways and so as to ensure continuity vital to the process of drawing, color in all modes is responsible for editing shapes on the surface imaging is, without a line, shape and dimensions
... Show MoreBackground: Expectoration of blood that originated in the lungs or bronchial tubes is a frightening symptom for patients and often is a manifestation of significant and possibly dangerous underlying disease. Tuberculosis was and still one of the common causes followed by bronchiactasis , bronchitis, and lung cancer. Objectives: The aim of this study is to find the frequency of causes of respiratory tract bleeding in 100 patients attending alkindy teaching hospital.Type of the study: : Prospective descriptive observational study Methods of a group of patients consist of one hundred consecutive adult patients, with Lower respiratory tract bleeding are studied. History, physical examination, and a group of selected investigations performed,
... Show MoreObjectives: To report the Cesarean section rate in Al-
Batool Maternity Teaching Hospital and to identify
how many of them were done for maternal and fetal
condition.
Design: A statistical cross sectional study.
Setting: The study was conducted at Al-Batool
Maternity Teaching Hospital (13000 deliveries per
year).
Participants: The patients group consists of 4556
patients admitted for delivery (vaginal and abdominal)
during a period of four months commencing from
January 2003.
Main outcome measures: calculation of all live
births, calculation of cesarean section rate, percentage
of the primary cesarean sections and the repeat
cesarean sections and listing the indications of the
operation acc
Origination for Teaching Physics at Secondary Stage main of the Educational Aims
This study carry’s out the correlation and the effect of two main variables, these variables are Job Satisfaction included six sub: wages - salaries and justice and yield, working conditions and services, pattern of supervision and the relationship with the manger, Relationship with colleagues, the content of the work and the variety of tasks, development and promotion opportunities available to an individual, and Organizational Performance included two sub variables: Efficiency, Effectiveness. This research was conducted using a questioner as a main tool, This questioner was distributed randomly to a research community composed of
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