Preferred Language
Articles
/
joe-1979
MIXED CONVECTIVE AND RADIATIVE HEAT TRANSFER IN A HORIZONTAL CONCENTRIC AND ECCENTRIC CYLINDRICAL ANNULI
...Show More Authors

A numerical investigation has been performed to study the effect of eccentricity on unsteady state, laminar aiding mixed convection in a horizontal concentric and eccentric cylindrical annulus. The outer cylinder was kept at a constant temperature
while the inner cylinder was heated with constant heat flux. The study involved numerical solution of transient momentum (Navier-Stokes) and energy equation using finite difference method (FDM), where the body fitted coordinate system (BFC) was
used to generate the grid mesh for computational plane. The governing equations were transformed to the vorticity-stream function formula as for momentum equations and to the temperature and stream function for energy equation.
A computer program (Fortran 90) was built to calculate the bulk Nusselt number (Nub) after reaching steady state condition for fluid Prandtl number fixed at 0.7 (air) with radius ratio ( =2.6), Rayleigh number (Ra=200), Reynolds number (Re=50) for both concentric and eccentric cylindrical annulus with different eccentricity ratios (ε=0, 0.25, 0.50, 0.75) and angular positions (φo=0o
, 45o , 90o , 135o , 180o ).
The results show a reasonable representation to the relation between Nusselt number and (ε, φo). Generally, Nub decreased with the increase in (ε and φo). Also, results show that the best thermal performance for the inner cylinder was at the angular
position (φo=0o ) for eccentricity ratio (ε=0.25), while the maximum reduction in the rate of heat transfer for the inner cylinder was at the angular position (φo=180o) for eccentricity ratio (ε=0.75).
Comparison of the result with the previous work shows a good agreement.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Wed Jun 30 2021
Journal Name
Journal Of Economics And Administrative Sciences
Evaluation of the reality of applying a number of Iraqi institutional accreditation standards/study in a number of Iraqi public and private universities
...Show More Authors

     The study aims to find out the extent to which several Iraqi institutional accreditation standards (governance and administration, scientific research, curricula) are applied in two public universities (Baghdad and Middle Technical University) and two private universities (Uruk and Al-Mansour College) by diagnosing strengths and weaknesses and proposing a mechanism and procedures to help educational institution aims to reduce or eliminate the gap. The study stems from the extent of application of several Iraqi institutional accreditation standards represented as it was worked on through observation and field coexistence to reach scientific and practical facts. The method of case study and comparison betwe

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Jun 30 2017
Journal Name
Journal Of Engineering
Performance Evaluation of a PID and a Fuzzy PID Controllers Designed for Controlling a Simulated Quadcopter Rotational Dynamics Model
...Show More Authors

This work is concerned with designing two types of controllers, a PID and a Fuzzy PID, to be used
for flying and stabilizing a quadcopter. The designed controllers have been tuned, tested, and
compared using two performance indices which are the Integral Square Error (ISE) and the Integral
Absolute Error (IAE), and also some response characteristics like the rise time, overshoot, settling
time, and the steady state error. To try and test the controllers, a quadcopter mathematical model has
been developed. The model concentrated on the rotational dynamics of the quadcopter, i.e. the roll,
pitch, and yaw variables. The work has been simulated with “MATLAB”. To make testing the
simulated model and the controllers m

... Show More
View Publication Preview PDF
Publication Date
Mon Jan 13 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation of the effect of addition of polyester fiber on some mechanical properties of heat cure acrylic resin
...Show More Authors

Background: This study aimed to evaluate the effect addition of polyester fibers on the some mechanical properties of heat cured acrylic resin (implant strength, flexural strength and hardness) Materials and methods: Ninety specimens were used in the study. Thirty specimens were used for impact strength measurements (80mm X 10mm X 4mm) length, width and thickness respectively. The specimens divided into three test groups (n=10), first group formed from heat cure acrylic resin without fiber reinforcement. Second group was formed from heat cure acrylic resin was reinforced with 2 mm length polyester fiber and third group was formed from heat cure acrylic resin reinforced with 4mm length polyester fiber, impact strength measured by impact test

... Show More
View Publication Preview PDF
Publication Date
Sun Apr 22 2018
Journal Name
Al-nahrain Journal For Engineering Sciences
Numerical Analysis of the Effect of Scanning Speed on the Temperature Field Distribution for Laser Heat Treatment Applications
...Show More Authors

One of the unique properties of laser heating applications is its powerful ability for precise pouring of energy on the needed regions in heat treatment applications. The rapid rise in temperature at the irradiated region produces a high temperature gradient, which contributes in phase metallurgical changes, inside the volume of the irradiated material. This article presents a comprehensive numerical work for a model based on experimentally laser heated AISI 1110 steel samples. The numerical investigation is based on the finite element method (FEM) taking in consideration the temperature dependent material properties to predict the temperature distribution within the irradiated material volume. The finite element analysis (FEA) was carried

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Thu Sep 01 2011
Journal Name
Journal Of Economics And Administrative Sciences
360 degree reverse feedback / comparative analytical study for a sample of managers and heads of departments in the Central Electricity DepartmentAnd the General Directorate of Water and Sewage
...Show More Authors

يسعى البحث إلى الاهتمام بإحدى الوظائف المهمة في إدارة الموارد البشرية وهي تقويم الأداء التي تواجه مجموعة من الانتقادات والآراء السلبية، اذ ظهر في الأّونة الأخيرة أنموذج جديد يمكن إن يتجاوز تلك السلبيات وهو أنموذج التغذية العكسية المتعدد المصادر درجة .وقد حاول الباحثان توظيف هذا المفهوم في اثنتين من المنظمات العامة العراقية هما (دائرة كهرباء الوسط) التابعة لوزارة الكهرباء
و (دائرة الماء والمجاري) ال

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Fri Jan 26 2024
Journal Name
Iraqi Journal Of Science
Purification and Properties of β-Galactosidase From A Thermophilic Fungus Rhizmmucor Pusillus IB8.
...Show More Authors

An extracellular β-galactosidase from the thermophilic fungus Rhizomucor
Pusillus IB8 has been purified via several steps included precipitation by ammonium
sulphate at 80 % saturation, DEAE- Cellulose Ion exchange chromatography and gel filteration on sepharose CL-6B column. The Final purification folds and the yield of the enzyme were 42.5 and 24.8 % respectively. The purified β-galactosidase has an optimum pH for its activity between 4.5 to 5, while the optimum pH for enzyme stability was between 5 to 5.5. Futhermore, it was found that the optimum temperature for its activity was 60 C°. The purified enzyme retained approximatly 98% of its original activity when incubated at 60 C° for 60 min. However, 25 % of its activity was

... Show More
View Publication Preview PDF
Publication Date
Sat Dec 30 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
A New Biological System For Detecting Environmetal Carcinogens And /Or Mutagenes And Their Adversary
...Show More Authors

A  new  test  system  for  detecting  environment  carcinogenes and/or  mutagenes  and  their  adversary  It  has  been  induced.  One hundred and fifty   mutants   were isolated from   the basidiomycete fungus Coprinus cinereus   which were   resistant to guanine analogue S- az.aguanine .All the spontaneous and induced with UV light origin mutants were isolated from the wild type strains Bc9/6.6 and  Hd5.5

.These mutants were te ted on selective medium containing  different

concentrations of the analogue and also to their ability to usc purine bases and their degredated &nbs

... Show More
View Publication Preview PDF
Publication Date
Sun Jul 01 2018
Journal Name
Vacuum
Stability, electronic and vibrational properties of GaAlN wurtzoid molecules and nanocrystals: A DFT study
...Show More Authors

View Publication
Scopus (7)
Crossref (6)
Scopus Clarivate Crossref
Publication Date
Tue Feb 02 2010
Journal Name
Advances In Software Engineering
A Strategy for Automatic Quality Signing and Verification Processes for Hardware and Software Testing
...Show More Authors

We propose a novel strategy to optimize the test suite required for testing both hardware and software in a production line. Here, the strategy is based on two processes: Quality Signing Process and Quality Verification Process, respectively. Unlike earlier work, the proposed strategy is based on integration of black box and white box techniques in order to derive an optimum test suite during the Quality Signing Process. In this case, the generated optimal test suite significantly improves the Quality Verification Process. Considering both processes, the novelty of the proposed strategy is the fact that the optimization and reduction of test suite is performed by selecting only mutant killing test cases from cumulating t-way test ca

... Show More
View Publication
Crossref (7)
Crossref
Publication Date
Thu Aug 24 2017
Journal Name
Clinical Case Reports
Primary hypogonadism, partial alopecia, and Müllerian hypoplasia: report of a fifth family and review
...Show More Authors
Key Clinical Message<p>Primary hypogonadism combined with Müllerian hypoplasia and partial alopecia are common features of this syndrome, which was reported only in four earlier families from areas where consanguineous marriage is prevalent. An autosomal recessive pattern of inheritance was suggested earlier and is supported by this report.</p>
View Publication
Crossref