Preferred Language
Articles
/
lRfweY4BVTCNdQwC-EnE
Investigation of phase change characteristics for refrigerant R-134a flow in a double pipe heat exchanger with the use of thermal non-equilibrium model
...Show More Authors

Almost all thermal systems utilize some type of heat exchanger. In a lot of cases, evaporators are important for systems like organic Rankine cycle systems. Evaporators give a share in a large portion of the capital cost, and their cost is significantly attached to their size or transfer area. Open-cell metal foams with high porosity are taken into consideration to enhance thermal performance without increase the size of heat exchangers. Numerous researchers have tried to find a representation of the temperature distribution closer to reality due to the different properties between the liquid and solid phases. Evaporation heat transfer in an annular pipe of double pipe heat exchanger (DPHEX) filled with cooper foam is investigated numerically with utilizing the local thermal non-equilibrium (LTNE) model. Warm water with constant inlet conditions flows in the inner pipe while R143a is used as cooling fluid in the annular pipe. The effects of pores per inch (PPI), mass flux of R134a and copper foam porosity on solid and fluid temperatures, liquid saturation and heat transfer coefficient are analysed and illustrated. Forchheimer-extended Darcy flow model is utilized with the adopting of the two-phase mixture model (TPMM). The governing equations in two-dimensional steady state regime were written in LTNE model. These equations were discretized using the finite volume method and a MATLAB program was built to solve these equations with its initial and boundary conditions. The obtained data illustrates that LTNE effect in metal foam is important for lower porosity, lower pore density and higher mass flux. The ratio of liquid will arrive its lowest value at the outlet, and it decreases with PPI increase and it increases with porosity and mass flux increase. The mean heat transfer coefficient approximately doubled when PPI increased from 10 to 50 and it increased by 70% when porosity decreased from 0.95 to 0.85.

Scopus Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Sun Jun 12 2011
Journal Name
Baghdad Science Journal
Hybrid(Luminescent and Fresnel ) Concentrators to Improve Solar Panel Conversion Efficiency
...Show More Authors

The spectral response of the Si solar cell does not coincidence with the sun irradiance spectrum, so the efficiency of the Si solar cell is not high. To improve the Si solar cell one try to make use of most region of the sun spectrum by using dyes which absorb un useful wavelengths and radiate at useful region of spectrum (by stock shift). Fluorescence's dye is used as luminescent concentrator to increase the efficiency of the solar cell. The results show that the performance efficiency and out power for crystalline silicon solar cells are improved.

View Publication Preview PDF
Crossref
Publication Date
Tue Jun 30 2015
Journal Name
Al-kindy College Medical Journal
Knowledge, attitude and practice regarding measles vaccine campaign among medical and engineering students: Baghdad, 2011
...Show More Authors

Background: The strategy for eliminating measles from Iraq includes conducting mass immunization campaign against measles, within the framework of the national strategic plan for the elimination of this disease. Awareness about this campaign is fundamental for their success.Objective: The study aims at finding out the knowledge, attitudes and practices regarding vaccination against measles among two groups of students in two different colleges ( medical and engineering) .To report uptake of Measles vaccine and reasons for declining the vaccine among medical and non-medical students in the campaignMethod: Across sectional study has been conducted at Al-Kindy College of Medicine/ Baghdad University and University of Technology for the peri

... Show More
View Publication Preview PDF
Publication Date
Sat Apr 13 2024
Journal Name
مجلة واسط للعلوم الریاضیة
تمرينات تنافسية لتطوير التوافق والتوازن وتأثيرها في مهارة التصويب السلمي للاعبات كرة السلة دون (18) سنة
...Show More Authors

Shooting skill in basketball is one of the most important offensive skills and the final stage of the team's attack and the culmination of all skills in which points are scored, including the skill of peaceful shooting. The research aims to prepare competitive exercises and understand the impact of competitive exercises on developing coordination and balance for basketball players under 18 years old. The researcher used the experimental method with the single experimental group approach, including the research community of female athletes in the public directorates of education in Baghdad, totaling (6) directorates and (72) players. The research sample was selected intentionally, consisting of female athletes in the sports activity of the D

... Show More
View Publication Preview PDF
Publication Date
Sun Jul 01 2012
Journal Name
Journal Of Educational And Psychological Researches
Arabic Calligraphy quality standards and teaching methods
...Show More Authors

Arabic calligraphy is one of the ancient arts rooted in history, And that he grew up conflicting views and writings addressed as a, communication tool for the linguistic The teaching calligraphy note an art and science because it depends on the fixed assets and precise rules in his art because centered Beauty It targets teach Arabic calligraphy speed as the education and recitation helps to write fast Which have great interest in the field of education and in life both Also accompanied Arabic calligraphy and scientific renaissance significant knowledge in the Ara

... Show More
View Publication Preview PDF
Publication Date
Mon May 20 2019
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
An Improved Image Compression Technique Using EZW and SPHIT Algorithms
...Show More Authors

 Uncompressed form of the digital images are needed a very large storage capacity amount, as a consequence requires large communication bandwidth for data transmission over the network. Image compression techniques not only minimize the image storage space but also preserve the quality of image. This paper reveal image compression technique which uses distinct image coding scheme based on wavelet transform that combined effective types of compression algorithms for further compression. EZW and SPIHT algorithms are types of significant compression techniques that obtainable for lossy image compression algorithms. The EZW coding is a worthwhile and simple efficient algorithm. SPIHT is an most powerful technique that utilize for image

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Tue Mar 30 2021
Journal Name
College Of Islamic Sciences
Divine orders Divine orders directed to his prophets (peace be upon them): Divine orders directed to his prophets (peace be upon them)
...Show More Authors

 

ملخص البحث:

    ان الله تعالى هو الذي خلق جميع المخلوقات ، والذي بيده الموت والحياة وان كل هذه المخلوقات تحتاج الى اوامر ، وهذه الاوامر الالهية وجهها الله لعبادة بوساطة انبياءه ( عليهم السلام) فكانوا هم اول المستسلمين والمنقادين لأوامره ، فجاءت الآيات الكريمة مخاطبة للأنبياء واقوامهم بشكل عام ولنبينا محمد (r) بشكل خاص.

اما عن المضمون البحثي فقد جاءت مادته مقسمة الى ثل

... Show More
View Publication Preview PDF
Publication Date
Sun Jan 01 2023
Journal Name
International Conference Of Computational Methods In Sciences And Engineering Iccmse 2021
Fibrewise totally topological spaces
...Show More Authors

View Publication Preview PDF
Scopus (1)
Scopus Crossref
Publication Date
Mon Oct 10 2016
Journal Name
Iraqi Journal Of Science
Satellite image classification using KL-transformation and modified vector quantization
...Show More Authors

In this work, satellite images classification for Al Chabaish marshes and the area surrounding district in (Dhi Qar) province for years 1990,2000 and 2015 using two software programming (MATLAB 7.11 and ERDAS imagine 2014) is presented. Proposed supervised classification method (Modified Vector Quantization) using MATLAB software and supervised classification method (Maximum likelihood Classifier) using ERDAS imagine have been used, in order to get most accurate results and compare these methods. The changes that taken place in year 2000 comparing with 1990 and in year 2015 comparing with 2000 are calculated. The results from classification indicated that water and vegetation are decreased, while barren land, alluvial soil and shallow water

... Show More
Publication Date
Tue Feb 01 2022
Journal Name
Baghdad Science Journal
Securing Text Messages Using Graph Theory and Steganography
...Show More Authors

      Data security is an important component of data communication and transmission systems. Its main role is to keep sensitive information safe and integrated from the sender to the receiver. The proposed system aims to secure text messages through two security principles encryption and steganography. The system produced a novel method for encryption using graph theory properties; it formed a graph from a password to generate an encryption key as a weight matrix of that graph and invested the Least Significant Bit (LSB) method for hiding the encrypted message in a colored image within a green component. Practical experiments of (perceptibility, capacity, and robustness) were calculated using similarity measures like PSNR, MSE, and

... Show More
View Publication Preview PDF
Scopus (9)
Crossref (4)
Scopus Clarivate Crossref
Publication Date
Tue Sep 01 2020
Journal Name
Baghdad Science Journal
Some Game via Ἷ-Semi-g-Separation Axioms
...Show More Authors

The research demonstrates new species of the games by applying separation axioms via  sets, where the relationships between the various species that were specified and the strategy of winning and losing to any one of the players, and their relationship with the concepts of separation axioms via  sets have been studied.

View Publication Preview PDF
Scopus Clarivate Crossref