Preferred Language
Articles
/
alkej-409
Enhancement of Heat Exchanger Performance by Using Dimpled Tube
...Show More Authors

The enhancement of heat exchanger performance was investigated using dimpled tubes tested at different Reynolds numbers, in the present work four types of dimpled tubes with a specified configuration manufactured, tested and then compared performance with the smooth tube and other passive techniques performance. Two dimpled arrangements along the tube were investigated, these are inline and staggered at constant pitch ratio X/d=4, the test results showed that Nusselts number (heat transfer) of the staggered array is higher than the inline array by 13%.  The effect of different depths of the dimple (14.5 mm and 18.5 mm) has been also investigated; a tube with large dimple diameter enhanced the Nusselts number by about 25% for the range of Reynolds number between 4000- 20000. The overall enhancement ratio was used to differentiate the passive technique and comparison of different configurations for the technique itself, the result depicted that the 10 mm dimple diameter with a pitch ratio of X/d= 4 gives better performance than the static mixer and twisted tape techniques. The overall enhancement ratio of the 10 mm dimple diameter is varied from (1.21 to 1.65) that means good performance for a range of Reynolds numbers (4000-20000). This indicates that 21- 65 % of heat transfer area can be saved at the same pumping power compared with the smooth tube heat exchanger. 

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Tue Jun 21 2022
Journal Name
مجلة جامعة الانبار للعلوم الانسانية
تطوير المدارس الثانوية باستخدام مفهوم المدرسة المتعلمة
...Show More Authors

Publication Date
Fri Jun 29 2018
Journal Name
Journal Of The College Of Education For Women
HandWritten Numerals Recognition System
...Show More Authors

  Recognition is one of the basic characteristics of human brain, and also for the living   creatures. It is possible to recognize images, persons, or patterns according to their characteristics. This recognition could be done using eyes or dedicated proposed methods. There are numerous applications for pattern recognition such as recognition of printed or handwritten letters, for example reading post addresses automatically and reading documents or check reading in bank.

      One of the challenges which faces researchers in character recognition field is the recognition of digits, which are written by hand. This paper describes a classification method for on-line handwrit

... Show More
View Publication Preview PDF
Publication Date
Fri Jun 01 2007
Journal Name
Journal Of Economics And Administrative Sciences
تقدير النموذج اللوجستي باستخدام اوزان بيز المتسلسل
...Show More Authors

تقدير النموذج اللوجستي باستخدام اوزان بيز المتسلسل

View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Sun Dec 01 2013
Journal Name
Baghdad Science Journal
Flow injection analysis for the photometric determination of promethazine-HCl in pure and pharmaceutical preparation via oxidation by persulphate using Ayah 3SX3-3D solar micro photometer
...Show More Authors

The first flow injection spectrophotometric method is characterized by its speed and sensitivity which have been developed for the determination of promethazine-HCl in pure and pharmaceutical preparation. It is based on the in situ detection of colored cationic radicals formed via oxidation of the drug with sodium persulphate to pinkish-red species and the same species was determined by using homemade Ayah 3SX3-3D solar flow injection photometer. Optimum conditions were obtained by using the high intensive green light emitted diode as a source. Linear dynamic range for the absorbance versus promethazine-HCl concentration was 0-7 mmol.L-1, with the correlation coefficient (r) was 0.9904 while the percentage linearity (r2%) was 98.09%. the L.

... Show More
View Publication Preview PDF
Crossref
Publication Date
Wed Jan 01 2025
Journal Name
Journal Of The Indian Chemical Society
Inspection the impact of mixing and external resistance on the Microbial Desalination Cell for electricity generation and desalination efficiency by using Macroalgae as a bio-cathode
...Show More Authors

View Publication Preview PDF
Scopus (7)
Crossref (7)
Scopus Clarivate Crossref
Publication Date
Mon Jun 10 2024
Journal Name
Iraqi Journal For Computer Science And Mathematics
Solving tri-criteria: total completion time, total late work, and maximum earliness by using exact, and heuristic methods on single machine scheduling problem
...Show More Authors

The presented study investigated the scheduling regarding  jobs on a single machine. Each  job will be processed with no interruptions and becomes available for the processing at time 0. The aim is finding a processing order with regard to jobs, minimizing total completion time , total late work , and maximal tardiness  which is an NP-hard problem. In the theoretical part of the present work, the mathematical formula for the examined problem will be presented, and a sub-problem of the original problem of minimizing the multi-objective functions  is introduced. Also, then the importance regarding the dominance rule (DR) that could be applied to the problem to improve good solutions will be shown. While in the practical part, two

... Show More
View Publication
Scopus (6)
Crossref (3)
Scopus Crossref
Publication Date
Fri Jan 11 2019
Journal Name
Iraqi Journal Of Physics
Porous silicon prepared by photo electrochemical etching assisted by laser
...Show More Authors

Porous silicon (PS) layers are prepared by anodization for
different etching current densities. The samples are then
characterized the nanocrystalline porous silicon layer by X-Ray
Diffraction (XRD), Atomic Force Microscopy (AFM), Fourier
Transform Infrared (FTIR). PS layers were formed on n-type Si
wafer. Anodized electrically with a 20, 30, 40, 50 and 60 mA/cm2
current density for fixed 10 min etching times. XRD confirms the
formation of porous silicon, the crystal size is reduced toward
nanometric scale of the face centered cubic structure, and peak
becomes a broader with increasing the current density. The AFM
investigation shows the sponge like structure of PS at the lower
current density porous begi

... Show More
View Publication Preview PDF
Crossref (4)
Crossref
Publication Date
Sat Jun 25 2022
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Measuring the extent to which listed companies comply with sustainability accounting standards by improving performance and financial reporting to enhance confidence in financial statements: بحث تطبيقي مقارن في عينة من الشركات العراقية والعربية
...Show More Authors

The objective of this research is to know the extent to which Iraqi and Arab companies apply the criteria of accounting for sustainability and disclosure, as well as to analyze the content of the annual financial reports of the companies listed in the financial market to determine their compliance with the Sustainability Accounting Standards Board )SASB(. Annual Report The commitment of telecommunications companies to implement sustainability issues related to the standard of telecommunications services reached a general average of (54%) for the sample of the research sample. This means that there is a degree of admissibility in applying the standard. As well as the highest level of reporting to the criterion of the (Jordan Telec

... Show More
View Publication Preview PDF
Publication Date
Thu Mar 18 2021
Journal Name
Egyptian Journal Of Chemistry
Investigation of the Influence of Membrane Type on the Performance of Microbial Fuel Cell
...Show More Authors

View Publication
Scopus (3)
Crossref (1)
Scopus Clarivate Crossref
Publication Date
Tue Dec 30 2008
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
The Effect of TCE Addition on the Performance of Catalytic Isomerization of n-Hexane
...Show More Authors

n-Hexane conversion enhancement was studied by adding TCE (Trichloro-ethylene) on feed stream using 0.3%Pt/HY zeolite catalyst. All experiments were achieved at atmospheric pressure and on a continuous laboratory unit with a fixed bed reactor at a temperature range 240-270◦C, LHSV 1-3h-1, H2/nC6 mole ratio 1-4.
By adding 435 ppm of TCE, 49.5 mole% conversion was achieved at LHSV 1h-1, temperature of 270ºC and H2/nC6 mole ratio of 4, while the conversion was 18.3 mol% on the same catalyst without adding TCE at the same conditions. The activation energy decreased from 98.18 for pure Pt/HY zeolite to 82.83 kJ/mole by adding TCE. Beside enhancement the activity, selectivity and product distribution enhanced by providing DMB (Dimethyl b

... Show More
View Publication Preview PDF