Preferred Language
Articles
/
alkej-587
Performance Estimation of Heat Exchanger Operates By Evaporative Cooling Manner
...Show More Authors

        In this study the design and installation of evaporative air cooler was carried out using completely outdoor air (fresh air) according to two stage evaporative cooling principle. The laboratory equipment was installed by designing and manufacturing a cross flow plate heat exchanger, where aluminum plates used for this purpose with dimensions (50 × 30 × 40 cm). The surfaces of heat exchanger were covered by sawdust from wetted channels side, to increase the percentage of wetting these surfaces and hence improve the performance and efficiency of air cooler.

        An experimental study was carried out to estimate the performance of cooling system, where some of the dominant effective parameters were studied like air flow rate and flow rate and effect the static pressure drop of air and the heat transfer of performance .Air flow rate was ranged between (142.90 to 1461.50 m3 / hr) and water flow rate was varied from (144 L / hr) to (1050 L / hr).

        The experimental results showed that the optimum flow rate of air prepared by the air cooler is (824.7 m3 / hr), As it to be seen from the study that treating the heat exchanger surfaces by sawdust improves the air cooler efficiency about (10 %), but in the other hand leads to increase the static pressure drop in proportion (21%) approximately, and hence increase consumed power about (9 %).The results also show the air cooler can not be used in regions that have moisture content accedes (11.90 g moisture/kg dry air).

 

View Publication Preview PDF
Quick Preview PDF
Publication Date
Mon Jun 01 2009
Journal Name
Journal Of Economics And Administrative Sciences
Use of lower squares and restricted boxes In the estimation of the first-order self-regression parameter AR (1) (simulation study)
...Show More Authors

Use of lower squares and restricted boxes
In the estimation of the first-order self-regression parameter
AR (1) (simulation study)

View Publication Preview PDF
Crossref
Publication Date
Mon Aug 01 2022
Journal Name
Baghdad Science Journal
Subgroups and Orbits by Companion Matrix in Three Dimensional Projective Space
...Show More Authors

The aim of this paper is to construct cyclic subgroups of the projective general linear group over  from the companion matrix, and then form caps of various degrees in . Geometric properties of these caps as secant distributions and index distributions are given and determined if they are complete. Also, partitioned of  into disjoint lines is discussed.

View Publication Preview PDF
Scopus (8)
Crossref (4)
Scopus Clarivate Crossref
Publication Date
Thu Mar 01 2007
Journal Name
Al-khwarizmi Engineering Journal
An investigation into the performance of counter rotating floating ring journal under different working conditions
...Show More Authors

The steady state performance of the counter rotating floating ring Journal bearing is analyzed with isothermal finite bearing theory. The effect of different parameters affecting the performance of the bearing (namely speed ratio, clearance ratio and radii ratio), have been investigated. The load carrying capacity of the bearing increasing with decreasing the radii ratio (R2/R1) of the ring and clearance ratio (c1/c2), in the other hand, the coefficient of friction increases with increasing the clearance and radii ratios, while decreases with incre4asing the bearing to journal speed ratio (γ). It is shown during this work that different operating conditions are greatly enhanced the performance

... Show More
View Publication Preview PDF
Publication Date
Sat Jul 01 2023
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The impact of the practice of professional doubt on the quality of the auditor's performance in Iraq: بحث استطلاعي
...Show More Authors

              Due to the increasing interest in the quality of auditing by writers, researchers and regulators of the auditing profession. The matter necessitated a statement of the extent to which the auditor practices professional skepticism, because of its significant impact in discovering errors and material misrepresentations contained in the financial statements in order to give the financial community confidence in them and the success of the audit process. The research aims to clarify the concept and importance of the practice of professional skepticism and its effect on the quality of the auditor's performance in Iraq. To achieve the research objectives, the two re

... Show More
View Publication Preview PDF
Publication Date
Fri Dec 01 2023
Journal Name
Baghdad Science Journal
Effect of Chromium (VI) on the Oxidation of Methylene Blue Dye by Fe3O4/ Chitosan Composite
...Show More Authors

     Heavy metal ion removal from industrial wastewater treatment systems is still difficult because it contains organic contaminants. In this study, functional composite hydrogels with photo Fenton reaction activity were used to decompose organic contaminants. Fe3O4 Nanoparticle, chitosan (CS), and other materials make up the hydrogel. There are different factors that affected Photo-Fenton activity including (pH, H2O2 conc., temp., and exposure period). Atomic force microscopy was used to examine the morphology of the composite and its average diameter (AFM). After 60 minutes of exposure to UV radiation, CS/ Fe3O4 hydrogel composite had degraded methylene blue (M.B.)

... Show More
View Publication Preview PDF
Crossref (4)
Crossref
Publication Date
Thu Feb 07 2019
Journal Name
Iraqi Journal Of Laser
Synthesis Characterization and Optical Properties of Nanostructured Zinc Sulfide Thin Films Obtained by Spray Pyrolysis Deposition
...Show More Authors

In this work, nanostructure zinc sulfide (ZnS) thin films at temperature of substrate 450 oC and thickness (120) nm have been produced by chemical spray pyrolysis method. The X-Ray Diffraction (XRD) measurements of the film showed that they have a polycrystalline structure and possessed a hexagonal phase with strong crystalline orientation of (103). The grain size was measured using scanning electron microscope (SEM) which was approximately equal to 80 nm. The linear optical measurements showed that ZnS nanostructure has direct energy gap. Nonlinear optical properties experiments were performed using Q-switched 532 nm Nd:YAG laser Z-scan system. The nonlinear refractive index (n2) and nonlinear absorption coefficient (β) estimated for Z

... Show More
View Publication Preview PDF
Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Performance Evaluation of Mobility Models over UDP Traffic Pattern for MANET Using NS-2
...Show More Authors

  The current study presents the simulative study and evaluation of MANET mobility models over UDP traffic pattern to determine the effects of this traffic pattern on mobility models in MANET which is implemented in NS-2.35 according to various performance metri (Throughput, AED (Average End-2-end Delay), drop packets, NRL (Normalize Routing Load) and PDF (Packet Delivery Fraction)) with various parameters such as different velocities, different environment areas, different number of nodes,  different traffic rates, different traffic sources, different pause times and different simulation times .  A routing protocol.…was exploited AODV(Adhoc On demand Distance Vector) and RWP (Random Waypoint), GMM (Gauss Markov Model), RPGM (Refere

... Show More
View Publication Preview PDF
Scopus (4)
Crossref (2)
Scopus Clarivate Crossref
Publication Date
Tue Jun 15 2021
Journal Name
Al-academy
Features of the actor's performance in the ritual theater (Iraqi theater as a model): علي شخير نفل
...Show More Authors

The features of the actor's performance in the ritual theater are of great importance and chief in theatrical work since the first emergence of the theater, as the features of the performance were embodied in all Iraqi theatrical performances, but they took personal privacy in some ritual performances because of their differences and similarities between the ritual theatrical performance and the ritual show Al-Khalis, who wanted the researcher to know the similarities and differences in the features of the ritual performance and in the theatrical performance, despite the many transformations that occurred in the theater and affected the features of the performance, but it remained an important and attractive link between the recipient, t

... Show More
View Publication Preview PDF
Crossref
Publication Date
Wed Feb 10 2016
Journal Name
ألمؤتمر الدولي العلمي الخامس للاحصائيين العرب/ القاهرة
Proposition of Modified Genetic Algorithm to Estimate Additive Model by using Simulation
...Show More Authors

Often phenomena suffer from disturbances in their data as well as the difficulty of formulation, especially with a lack of clarity in the response, or the large number of essential differences plaguing the experimental units that have been taking this data from them. Thus emerged the need to include an estimation method implicit rating of these experimental units using the method of discrimination or create blocks for each item of these experimental units in the hope of controlling their responses and make it more homogeneous. Because of the development in the field of computers and taking the principle of the integration of sciences it has been found that modern algorithms used in the field of Computer Science genetic algorithm or ant colo

... Show More
Preview PDF
Publication Date
Fri Mar 01 2019
Journal Name
Al-khwarizmi Engineering Journal
Multiwavelet and Estimation by Interpolation Analysis Based Hybrid Color Image Compression
...Show More Authors

Nowadays, still images are used everywhere in the digital world. The shortages of storage capacity and transmission bandwidth make efficient compression solutions essential. A revolutionary mathematics tool, wavelet transform, has already shown its power in image processing. The major topic of this paper, is improve the compresses of still images by Multiwavelet based on estimation the high Multiwavelet coefficients in high frequencies sub band  by interpolation instead of sending all Multiwavelet coefficients. When comparing the proposed approach with other compression methods Good result obtained

View Publication Preview PDF