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Experimental Study on the Effect of Using Metallic Brushes on the Charging and Discharging Time of Thermal Energy Storage Unit
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Phase change materials are known to be good in use in latent heat thermal energy storage (LHTES) systems, but one of their drawbacks is the slow melting and solidification processes. So that, in this work, enhancing heat transfer of phase change material is studied experimentally for in charging and discharging processes by the addition of high thermal conductive material such as copper in the form of brushes, which were added in both PCM and air sides. The additions of brushes have been carried out with different void fractions (97%, 94% and 90%) and the effect of four different air velocities was tested. The results indicate that the minimum brush void fraction gave the maximum heat transfer in PCM and reduced the time for melting for (ϵ=90%) up to 4.49 times as compare with the case of no brush. It can be seen that the addition of brushes in air side helped to reduce the solidification time and increase the convection heat transfer coefficient as the brush void fraction decreased. Also the minimum velocity (v = 1 m/s) gave maximum outlet temperature.

 

 

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Publication Date
Wed Mar 29 2023
Journal Name
Journal Of The College Of Education For Women
A Cognitive Linguistic Study of the Present Simple: An Experimental Study in the University of Baghdad
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Some research reports that cognitive grammar (CG) theory has good contributions to teaching English as a foreign language. In this research, the researchers seek to apply this theory and its principles when teaching the simple present tense to Iraqi students who face difficulties in differentiating between the multiple usages of this tense. To achieve this objective, the researchers have conducted an experimental study on a group of 60 Iraqi students in the University of Baghdad, College of Education for Women. Langacker’s (2003) theory has been adopted in the analysis of the cognitive relations to understand the common and different connections of these usages of the simple present. The study has concluded that the cognitive grammar t

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Publication Date
Thu Aug 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
Factors that Effect on the Level of Accounting Conservatism A sample study Of insurance companies which listed on the Amman Stock Exchange (2005-2016)
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This study aimed to measure  the accounting conservatism  and the lemited factors which  affected on it in the annual financial reports of insurance companies which listed on the Amman Stock Exchange during the period from 2005 to 2016, these factors were represented by firm age, firm debt and firm size.

Using the market value model (MV) To book value  ( BV) Beaver and Ryan (2000) The level of the accounting conservatism was measured. The study found that the insurance companies which are listed on the ASE exercise the accounting conservatism when they were  preparing financial reports. And when conducting a process  of the test of the affected of the factors (The age of the

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Publication Date
Thu Oct 02 2025
Journal Name
Journal Of Baghdad College Of Dentistry
The surface roughness of new fluoride releasing material after using three polishing protocols and storage in artificial saliva
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Background: Prophylaxis methods are used to mechanically remove plaque and stain from tooth surfaces; such methods give rise to loss of superficial structure and roughen the surface of composites as a result of their abrasive action. This study was done to assess the effect of three polishing systems on surface texture of new anterior composites after storage in artificial saliva. Materials and methods: A total of 40 Giomer and Tetric®N-Ceram composite discs of 12 mm internal diameter and 3mm height were prepared using a specially designed cylindrical mold and were stored in artificial saliva for one month and then samples were divided into four groups according to surface treatment: Group A (control group):10 specimens received no surfa

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Publication Date
Fri Jan 01 2021
Journal Name
Journal Of Economics And Administrative Sciences
Measuring and analyzing the effect of foreign debt on the gross domestic product in Morocco for the period 1990-2017 using the ARDL Test
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The research aims to identify the magnitude of the impact of external debt on the gross domestic product in Morocco, and the importance of research lies in the role that external debt plays in addressing structural imbalances, if it is best disposed of according to well-studied economic plans by specialists in this regard, especially if these debts are directed with Other resources, as it helps pay the costs of these debts (debt servicing) that the external debt also raises the level of gross domestic product, and the research starts from the hypothesis that: There is an effect of foreign debt on the GDP in Morocco, has contributed in one way or another to The exacerbation of the external debt, which affected the m

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Publication Date
Fri Oct 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
The effect of the marketing channel of the service on marine insurance losses: a case study in the Iraqi insurance company
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All businesses seek to improve their levels of profits through various means, most notably their marketing channels, which ensure the delivery of their products to their customers in a safe manner in a timely manner. It considers losses to a minimum and that insurance companies place great interest in marine insurance losses because they often constitute huge amounts compared to other losses, hence the problem of research, which is centred on the type and size of the impact owned by the channel The Iraqi insurance company was chosen to be applied according to the intentional sample method because this company is closely related to the subject matter. The research has reached a set of conclusions, most notably that the choice of i

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Publication Date
Tue Aug 15 2023
Journal Name
Sumer 1
Evaluation of the effects of Curcumin gel against Periodontopathic Bacteria (Porphyromonas gingivalis) using real-time time-polymerase chain reaction technology
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Periodontal disease is typically treated with mechanical debridement of the tooth surface. It may, however, be insufficient to eradicate pathogenic microorganisms on its own. Because of the microbial etiology of periodontitis, systemic or local antibiotic therapy is used as an adjunct treatment. The present study aimed to determine the effects of curcumin gel on Porphyromonas gingivalis. Eleven patients with stage II and III periodontitis were registered in the study. A double-blinded split-mouth design followed. Periodontal pockets were distributed into 2 groups; the test group received scaling and root planing along with curcumin gel, while the control group received scaling and root planing along with a placebo gel. Plaque index,

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Publication Date
Thu Oct 02 2025
Journal Name
Iraqi Journal Of Mechanical And Material Engineering
STUDY ON THE PARAMETER OPTIMIZATION INMAGNETIC ABRASIVE POLISHING FORBRASS CUZN33PLATE USING TAGUCHI METHOD
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This paper describes a new finishing process using magnetic abrasives were newly made to finish effectively brass plate that is very difficult to be polished by the conventional machining processes. Taguchi experimental design method was adopted for evaluating the effect of the process parameters on the improvement of the surface roughness and hardness by the magnetic abrasive polishing. The process parameters are: the applied current to the inductor, the working gap between the workpiece and the inductor, the rotational speed and the volume of powder. The analysis of variance(ANOVA) was analyzed using statistical software to identify the optimal conditions for better surface roughness and hardness. Regressions models based on statistical m

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Publication Date
Thu Oct 02 2025
Journal Name
Journal Of Baghdad College Of Dentistry
The effect of curvature angle and rotational speed on the cyclic fatigue of three types of rotary instrument (In vitro): comparative study
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Background: The fracture of instruments within root canal during endodontic treatment is a common incidence, fracture because of fatigue through flexure occurs due to metal fatigue, this study aimed to assess the effect of curvature angle and rotational speed on the cyclic fatigue of different type of Endodontic NiTi Rotary Instruments and compare among them. Materials and method: Three types of rotary instruments with tip size 0.25: ProTaPer F2 (Densply, Malifier) Revo-S SU( 0.06 taper, MicroMega) and RaCe system (0.06 taper, FKG, Dentaire), Forty file of each instrument were used within two canals with angle of curvature (40 &60 )at two speed (250&400)RPM, twelve group were formed for all instruments(total number=120),ten file fo

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Publication Date
Sat Jun 06 2020
Journal Name
Journal Of The College Of Education For Women
Spatial Analysis of Soil Characteristics and its Effect on Determining the Susceptibility of lands of the RasheedRegion: A Study in Soil Geography
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Twelve pends were selected and distributed on three verticals transects paths on the Tigers river in Al Rasheed county.Passing through land covers, that classified and covers the whole region. Based on the 8 Landsat of the year 2015. It was oriental classified by using Erdas 10.2 . The pedons were distributed on the area of each varicty of these classes. the series of soil according of the transect series (DW74,MMg,DMu6 , Df96) respectively were represented P1 , P2 , P3 , P4  .

The second transits series(DM97,MM5,DM96,DF115) respectively were  represented P5 , P6 , P7 , P8  .The third  transits series(DM46,MMg,MF12,MM11) re

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Publication Date
Mon Nov 01 2021
Journal Name
International Journal Of Hydrogen Energy
Experimental study on combustion stability and performance of hydrogen-enriched compressed natural gas of a free-piston linear generator
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