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Study Effect of Central Rectangular Perforation on the Natural Convection Heat Transfer in an Inclined Heated Flat Plate
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Anumerical solutions is presented to investigate the effect of inclination angle (θ) , perforation ratio (m) and wall temperature of the plate (Tw) on the heat transfer in natural convection from isothermal square flat plate up surface heated (with and without concentrated hole). The flat plate with dimensions of (128 mm) length × (64 mm) width has been used five with square models of the flat plate that gave a rectangular perforation of (m=0.03, 0.06, 0.13, 0.25, 0.5). The values of angle of inclination were (0o, 15o 30o 45o 60o) from horizontal position and the values of wall temperature (50oC, 60 oC, 70 oC, 90 oC, 100oC). To investigate the temperature, boundary layer thickness and heat flux distributions; the numerical computation is carried out using a very efficient integral method to solve the governing equation. The results show increase in the temperature gradient with increase in the angle of inclination and the high gradient and high heat transfer coefficients located in the external edges of the plate, for both cases: with and without holed plate. There are two separation regions of heat transfer in the external edge and the internal edges. The boundary layer thickness is small in the external edge and high in the center of the plate and it decreases as the inclination angle of plate increases. Theoretical results are compared with previous result and it is found that the Nusslet numbers in the present study are higher by (22 %) than that in the previous studies. And the results show good agreement in range of Raleigh number from 105 to 106.

 

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Publication Date
Thu Nov 30 2023
Journal Name
Iraqi Journal Of Science
Study of Optical, Structural and Morphology Properties of Tin Oxide Nanoparticles by Pulse Laser Ablation and its Effect on Bacteria Staphylococcus aureus
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     Tin oxide (Sn) nanoparticles were prepared by pulsed laser ablation (PLA) method at different laser energies (400-700mJ). (UV, XRD, AFM, SEM, EDS) methods were employed to determine the properties of nanomaterials. The optical properties showed that the energy gap decreased with increasing laser power; the structural properties showed the relationship between density and angle; Miller's coefficients for net angles were determined and the morphology properties showed the element's surface shape and surface roughness. Also, Tin oxide nanoparticles with added to Staphylococcus aureus bacteria isolated from the ear and cultured by striking method on nutrient agar to know the effect of tin oxide nanoparticles on the growth o

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Publication Date
Sat Jul 27 2024
Journal Name
International Journal Of Economic Perspectives
The impact of strategic leadership on the building of intelligent organizations: A field study of a group of economic institutions in Algeria
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This study aims to highlight the role of strategic leadership in adopting the intelligent organization model. The study was conducted on 7 economic organizations in Algeria. The study population consisted of 354 leaders, of whom a random sample of 176 leaders (managers, department heads, division heads, engineers) was selected. The researcher used a questionnaire as the main tool of the study. Statistical analysis and hypothesis testing were conducted using SEM (Structural Equation Modeling) with the aid of SPSS.v26 and AMOS.v24 software. The study concluded with a set of results, most notably: there is a statistically significant direct positive effect between strategic leadership and building intelligent organizations at a significance le

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Publication Date
Fri Dec 15 2017
Journal Name
Journal Of Baghdad College Of Dentistry
The Influence of Different Fabrication and Impression Techniques on the Marginal Adaptation of Lithium Disilicate Crowns (A comparative in vitro study)
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Background: The marginal adaptation has a key role in the success and longevity of the fixed dental restoration, which is affected by the impression and the fabrication techniques .The objective of this in vitro study was to evaluate and compare the marginal fitness of lithium disilicate crowns using two different digital impression techniques (direct and indirect techniques) and two different fabrication techniques (CAD/CAM and Press techniques). Materials and Methods: Thirty two sound upper first premolar teeth of comparable size extracted for orthodontic reason were selected in this study .Standardized preparation of all teeth samples were carried out with modified dental surveyor to receive all ceramic crown restoration with 1 mm deep

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Publication Date
Tue Feb 25 2025
Journal Name
Journal Of Baghdad College Of Dentistry
The effects of bisphosphonate administration on teeth development and growth of the jaw bones in neonatal rats (histological and immunohistochemical study)
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Background: Bisphosphonates are potent inhibitors of osteoclastic bone resorption and widely used for the treatment of osteoporosis, and osteogenesis imperfecta in children. Clinical and experimental studies have demonstrated that Bisphosphonates delay or inhibit tooth eruption. This study tries to focus on the effect of bisphosphonate on teeth development and jaw bones growth. Materials and methods: The present study includes 65 neonatal rats during lactation period from 15 Albino Wister rats mother. Alendronate (one type of Bisphosphonates) was administrated orally (15 mg/kg) into 10 pregnant rats two times a week, while other 5 rats regard as control. Then the neonatal rats sacrificed in I, 6, 11, 16 and 21 days. The lower first molar we

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Publication Date
Sun Jun 03 2018
Journal Name
Baghdad Science Journal
Influence of Lead Exposure in the Expression of Calmodulin – Related Genes: A Preliminary Study on Workers Working in Industry of Batteries, In Iraq
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Most pathological effects of lead on the body are due to ability of lead to bind with important cellular molecules of various tissues and organs leading to formation abnormal molecules and thus to emergence of pathological conditions. To evaluation the risk to the health status of Iraqi workers who work in the batteries industry, expression of three types of calmodulin related genes were examined. Blood samples were collected from worker working in Iraqi industry of batteries (located in Al-Waziriya), then RNAs extraction were done thereby gene expression for Calcium/Calmodulin- dependent protein kinase2 (CaMKK2), C-X-C Chemokine receptor 4 (CXCR4) and mitogen activated protein kinase kinase 6 (MAP2K6) was done for each sample by using RT-q

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Publication Date
Sun Jan 01 2023
Journal Name
Journal Of University Of Babylon For Engineering Sciences
Introduction to Methods for Simulating Urban Heat Islands: Subject Review
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Urbanization led to significant changes in the properties of the land surface. That appends additional heat loads at the city, which threaten comfort and health of people. There is unclear understanding represent of the relationship between climate indicators and the features of the early virtual urban design. The research focused on simulation capability, and the affect in urban microclimate. It is assumed that the adoption of certain scenarios and strategies to mitigate the intensity of the UHI leads to the improvement of the local climate and reduce the impact of global warming. The aim is to show on the UHI methods simulation and the programs that supporting simulation and mitigate the effect UHI. UHI reviewed has been conducted the for

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Publication Date
Wed Apr 29 2020
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Alternating Directions Implicit Method for Solving Homogeneous Heat Diffusion Equation
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     An Alternating Directions Implicit method is presented to solve the homogeneous heat diffusion equation when the governing equation is a bi-harmonic equation (X) based on Alternative Direction Implicit (ADI). Numerical results are compared with other results obtained by other numerical (explicit and implicit) methods. We apply these methods it two examples (X): the first one, we apply explicit when the temperature .

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Publication Date
Thu Jan 01 2015
Journal Name
Journal Of Engineering
Shell and Double Concentric Tube Heat Exchanger Calculations and Analysis
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This study concerns a new type of heat exchangers, which is that of shell-and-double concentric tube heat exchangers. The case studies include both design calculations and performance calculations.

       The new heat exchanger design was conducted according to Kern method. The volumetric flow rates were 3.6 m3/h and 7.63 m3/h for the hot oil and water respectively. The experimental parameters studied were: temperature, flow rate of hot oil, flow rate of cold water and pressure drop.

A comparison was made for the theoretical and experimental results and it was found that the percentage error for the hot oil outlet temperature was (- 1.6%). The percentage

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Publication Date
Thu May 04 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
The Effect of Electromagnetic Current in the Plantlet in vitro in Cucumis sativus L.
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Seeds of three American species of cucumber:-Lot number (EM285) signed as number 1,
To CAEEN F1 signed as number 2 ,and Hybird Super Green F1 signed as number 3, were
exposed to two kinds of physical effects .They were given :- 4 frequencies of the electric
current (0,1,2and 2.5) Am for five minutes using electro- magnetic generator .Then the three
species exposed to Ultra-Violet (UV)wave for four periods (0,30,60 and 90)sec. respectively
at 254 nm using Hood light .After exposure time the seeds were planted in sterlized
media(MS) with Benzyladenine (BA)and left in the incubator for2-3 weeks .Then ,plantlets of
the three species were taken to study the root system ,shoot system ,dry and wet weight for
them

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Publication Date
Tue Nov 30 2021
Journal Name
Iraqi Journal Of Science
Clinical and Histopathological Study on Dog's Tumors in Iraq
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The study was conducted on twenty dogs from variety breeds to estimate the
incidence of tumor mass and determine the risk factors of survey to cases of a year
in veterinary hospital in Baghdad. The most common clinical signs were, ulceration,
bleeding into lesions in addition to drowsiness, anorexia, fever and the others were
depended tumor's location in dog's body like lameness, lacrimation and bloody
constipation etc.
The results showed 70% of the infected dogs were working with military forces
and 30% of them were pet dogs and we found that the highest percentage of tumor
accrued in dogs aged more than 10 years and the females recorded 60% of infection.
Terrier breed had the highest percentage of infection (

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