The Nano materials play a very important role in the heat transfer enhancement. An experimental investigation has been done to understand the behaviors of nano and micro materials on critical heat flux. Pool boiling experiments have used for several concentrations of nano and micro particles on a 0.4 mm diameter nickel chrome (Ni-Cr) wire heater which is heated electrically at atmospheric pressure. Zinc oxide(ZnO) and silica(SiO2) were used as a nano and micro fluids with concentrations (0.01,0.05,0.1,0.3,0.5,1 g/L), a marked enhancement in CHF have been shown in the results for nano and micro fluids for different concentrations compared to distilled water. The deposition of the nano particles on the heater surface was the reason behind the enhancement of the wettability of the surface which will increase the CHF, this nano particles deposition will form a porous layer and the mechanism of the formation of this layers is that as vapor bubbles grow, the evaporating liquid in the micro layer leaves behind Nano particles which then will be concentrated at the base of the bubble to form this pours layer. The higher wettability can produce CHF enhancement, the enhancement ratio of Nano fluid is observed to be higher than that of micro fluid, the optimum enhancement ratios of nano fluid is (1 g/l) which observed to be 9.2 % for ZnO and 8.7% for Sio2, and also (1 g/l) for micro fluid which observed to be 8.1%for ZnO and 7.4%for SiO2.
The long healing time of bone after tooth extraction in order to construct artificial teeth is uncomfortable to the patient because of aesthetic or masticatory problems in addition to the daily visit to dental clinic. The objective of this study was to evaluate the effect of 805 nm diode laser with long time intervals on repair of bone and skin incisions in rabbits through biochemical, radiological and histological findings. Eighteen New-Zealand rabbits were undergone surgical operations to make a cavity in the bone of the lower jaw, the rabbits were divided into two groups:- Group A (control group) containing nine rabbits. Group B (lased group) containing nine rabbits in which two cavities were done, one on the right side and the other
... Show MoreThe effect of 410nm with 100 mW output power and one centimetre spot size (0.128 W/cm2 power density) Diode laser irradiation at different exposure times on the growth of Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus was evaluated. Seventy swap samples were collected from burn and infected wounds of 35 patients admitted to the burn-wound unit in Al-Yarmouk Teaching Hospital in Baghdad during the period from December 2014 to February 2015. These bacteria were isolated and identified depending on their growth on selective media, cultural characteristics, Gram stain morphology and biochemical tests and finally were confirmed by Vitek 2 compact system test .Susceptibility of bacterial isolates to 15antibiotics
... Show MoreObjective: One of the most important practical deficiencies of present denture base materials is fracture, therefore many
attempts have been made to reinforce of the repaired denture base resin. A desirable objective for this service is to obtain
optimum strength for repairs, which can be achieved by making available a good bond between original and repaired
materials.
Methodology: The present study was carried out to evaluate and compare the transverse strength of acrylic specimens
repaired by two different materials (hot-cure and cold-cure acrylic resin). A total of 50 specimens were prepared by hot
(40) repair: (10) by hot with retention bead, (10) by cold with retention bead and (10) repair by hot only, (10) repair
The aim of this study to identity using Daniel's model and Driver’s model in learning a kinetic chain on the uneven bars in the artistic gymnastics for female students. The researchers used the experimental method to design equivalent groups with a preand post-test, and the research community was identified with the students of the third stage in the college for the academic year 2020-2021 .The subject was, (3) class were randomly selected, so (30) students distributed into (3) groups). has been conducted pretesting after implementation of the curriculum for (4) weeks and used the statistical bag of social sciences(SPSS)to process the results of the research and a set of conclusions was reached, the most important of which is t
... Show MoreBackground:In this study,TiO2 layer was thermally grown as a diffusion barrier on CP Ti substrate prior to electrophoretic deposition of HA coatings, to improve the coating’s compatibility also macro and micro pores in nano Hydroxyapatite dual coatings were created and their effect on the bond strength between the bone and implant was evaluated. Materials and methods: Electrophoretic Deposition technique (EPD) was used to obtain coatings for each one of four types of Hydroxyapatite(HA)on CP Ti screws (micro HA, nano HA, dual nano HA with micro pores, dual nano HA with macro pores) where carbon particles used as fugitive material to be removed by thermal treatment to create porosity.For examination of the changes occurred on the subs
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This paper has investigated experimentally the dynamic buckling behavior of AISI 303 stainless steel Aluminized and as received long columns. These columns, hot-dip aluminized and as received, are tested under dynamic buckling, 22 specimens, without aluminizing (type 1), and 50 specimens, with hot-dip aluminizing at different aluminizing conditions of dipping temperature and dipping time (type 2), are tested under dynamic compression loading and under dynamic combined loading (compression and bending) by using a rotating buckling test machine. The experimental results are compared with Perry Robertson interaction formula that used for long columns. Greenhill formula is used to get a mathematical model that descripts the buckling behavior
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Proteus mirabilis is considered as a third common cause of catheter-associated urinary tract infection, with urease production, the potency of catheter blockage due to the formation of biofilm formation is significantly enhanced. Biofilms are major virulence factors expressed by pathogenic bacteria to resist antibiotics; in this concern the need for providing new alternatives for antibiotics is getting urgent need, This study aimed to explore whether green synthesized zinc oxide nanoparticles (ZnO NPs) can function as an anti-biofilm agent produced by P.mirabilis. Bacterial cells were capable of catalyzing the biosynthesis process by producing reductive enzymes. The nanoparticles were synthesized from cell free
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Background: Alginate impression material is the irreversible hydrocolloid material that is widely used in dentistry. The contact time between alginate and gypsum cast could have a detrimental effect on the properties of the gypsum cast. The objective of this study is to evaluate the impact of various contact time intervals of Alginate impressions & type III dental stone on surface properties of stone cast. Materials and Methods: Time intervals tested were 1hour, 6 hours and 9 hours. Surface properties of stone cast evaluated were surface detail reproduction, hardness and roughness. Surface detail reproduction was determined using cylindrical brass test block in accordance with ISO 1563. Surface roughness was measured by profilometer
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Abstract
The current research aims to know the reality of the research's coefficients, to know correlation and effectiveness between the organizational Agility and high performance . The current research has been applied on the official banks , including a sample of senior administration members (120) ; besides , the research has used questionnaire that being considered as the main tool for gathering information and data . It includes 59 questions in addition to the personal interviews program as to support the questionnaire and to fulfill a great deal of reality. It has been anal
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