Preferred Language
Articles
/
joe-796
Thermal Efficiency for Passive Solar Chimney with and Without Heat Storage material
...Show More Authors

In this study, a different design of passive air Solar Chimney(SC)was tested by installing it in the south wall of insulated test room in Baghdad city. The SC was designed from vertical and inclined parts connected serially together, the vertical SC (first part) has a single pass and Thermal Energy Storage Box Collector (TESB (refined paraffin wax as Phase Change Material(PCM)-Copper Foam Matrix(CFM))), while the inclined SC was designed in single pass, double passes and double pass with TESB (semi refined paraffin wax with copper foam matrix) with selective working angle ((30o, 45o and 60o). A computational model was employed and solved by Finite Volume Method (FVM) to simulate the air induced through the test room by SC effect. The governing equation of Computational Fluid Dynamic (CFD) model was developed by the effective heat capacity method equation to describe the heat storage and release from PCM-CFM. Practical and computational Results referred to increase in thermal conductivity of the paraffin wax that supported by CFM than 10 times, while the ventilation effect is still active for hours after sun set amount. The maximum ventilation mass flow rate with TESB collector was 36.651 kg/hr., when the overall discharge coefficient equals 0.371. Also, the experimental results referred to the best working angle range 45~60o, while the highest approaching temperature (between air and collector) was appeared for the double passes flat plate collector. Results gave higher heat storage efficiency 47% when the maximum solar radiation 780 W/m2 at 12.00 pm, and the energy summation through duration of charging time was 18460 kJ. Double passes SC at 60o angle presented the highest efficiency with value approaching to 73%, while TESB collector efficiency depicted highest efficiency value 70% at 12:00 pm.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Sun Jan 01 2023
Journal Name
Journal Of Clinical And Experimental Dentistry
Preventive effect of combined Er, Cr: YSGG and fluoride gel on acid resistance of the permanent tooth enamel: An in vitro study
...Show More Authors

View Publication
Crossref (4)
Crossref
Publication Date
Thu Apr 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
The Effect of organizational stress on the Performance of professor at the Faculty of Economics and Commercial Sciences / University of Djelfa / Algeria
...Show More Authors

The present study aims at identifying the effect of organizational pressure with its aspects (management, work team, nature and conditions of work, external environment) on job performance in all its dimensions (commitment and effort made, capabilities and the rapidity of performance, motivation and job satisfaction, work environment) for the university teacher at the Faculty of Economics, Commercial and Management Sciences at the University of Djelfa, Algeria.

     In this research, the descriptive analytical approach is used. Data was collected through the distribution of a questionnaire to a sample that included 130 permanent teachers before being analyzed using the (SPSS) statisti

... Show More
View Publication Preview PDF
Crossref
Publication Date
Thu Jan 29 2026
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
...Show More Authors

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

... Show More
View Publication Preview PDF
Publication Date
Wed Dec 22 2021
Journal Name
Plos One
Awareness and preparedness of healthcare workers against the first wave of the COVID-19 pandemic: A cross-sectional survey across 57 countries
...Show More Authors
Background

Since the COVID-19 pandemic began, there have been concerns related to the preparedness of healthcare workers (HCWs). This study aimed to describe the level of awareness and preparedness of hospital HCWs at the time of the first wave.

Methods

This multinational, multicenter, cross-sectional survey was conducted among hospital HCWs from February to May 2020. We used a hierarchical logistic regression multivariate analysis to adjust the influence of variables based on awareness and preparedness. We then used association rule mining to identify relationships between HCW confidence in handling suspected

... Show More
View Publication
Scopus (28)
Crossref (29)
Scopus Clarivate Crossref
Publication Date
Wed Jun 04 2025
Journal Name
Kufa Journal For Agricultural Sciences – 2025:17(2) : 56- 65
Efficacy of different Conidial concentrations, fungal Filtrations and silver nanoparticles Mycosynthesis using two isolates of Metarhizium anisoplae against Two Stored-grain Insects
...Show More Authors

Publication Date
Mon Jun 30 2025
Journal Name
مجلة القادسية للقانون والعلوم السياسية
Insurance of Unlawful Risks: Towards a Reinterpretation of Public Policy in Light of the Protection of Innocent Victims and Freedom of Contract
...Show More Authors

The issue of insurance against unlawful risks raises a jurisprudential and judicial debate between two opposing trends: the first considers coverage of these risks invalid due to their impact on public order or morals, while the second—which this research analyses—calls for the possibility of covering these risks in specific circumstances, based on contractual considerations in accordance with the principle that the contract is the law of the contracting parties, and based on the obligation to compensate the harmed third party—the victim—who has no connection to the unlawful act. In this context, our research highlights that contractual considerations can justify coverage of some unlawful risks, provided that the goal is to achieve

... Show More
View Publication
Publication Date
Wed Apr 01 2020
Journal Name
Indian Journal Of Forensic Medicine And Toxicology
Study the genotoxicity of aqueous and alcoholic extracts of adhatoda vasica on the roots of allium cepa L. By RAPD-PCR technique
...Show More Authors

Scopus (2)
Scopus
Publication Date
Thu Jan 29 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Craniometric asymmetry assessment in class I and class II skeletal relationship patients using helical computed tomography sample aged between 18-35 years
...Show More Authors

Background: Asymmetry assessment is an important component of orthodontic diagnosis and treatment planning. Several studies attempted to find the relationship between craniometric asymmetry and skeletal jaws relationship and many authors found some extent of asymmetry in individuals with normal jaws relationship. The use of Computed tomography (CT) allows for the assessment of asymmetry on a dimensionally accurate volumetric image, aim of the study is to determine if there are differences in craniometric asymmetry between patient with skeletal class I and patients with skeletal class II relationship using Helical CT scan. Materials and Methods: Ninety individuals with clinically symmetrical faces were imaged with Helical CT scan, and aging

... Show More
View Publication Preview PDF
Publication Date
Wed Jan 01 2025
Journal Name
Smart Innovation, Systems And Technologies
The Effect of Bulgarian Bag Exercises to Develop Explosive Force, Characterized by Speed and Accuracy of the Spiking Performance of Volleyball Players
...Show More Authors

The purpose of this study is to develop and assess the effectiveness of exercises using heavy and hanging ropes for handball players, focusing on enhancing specific physical abilities and shooting accuracy. The research addresses the gap in training methodologies by comparing the effects of heavy rope exercises versus hanging rope exercises. An experimental design was used in two equal groups, besides pre-testing and post-testing. The study involved 16 players from the School of Handball for the season 2022–2023. The sample included 14 players, who were then randomly divided into two experimental groups of 7 each. The first group performed heavy rope exercises, while hanging rope exercises were included in the plan of the second group. Th

... Show More
View Publication
Scopus Crossref
Publication Date
Mon Oct 22 2018
Journal Name
Journal Of Economics And Administrative Sciences
Performance Appraisal of Human Resource Management and Its Effect on Achieving the Organizational Success -A Field Search at the Ministry of Oil-
...Show More Authors

The present study addressed "Performance Appraisal of Human Resource Management and Its Effect on Achieving the Organizational Success", for the topics of performance appraisal of human resource management and the organizational success gained an increasing interest being relatively important and modern topics which had a great effect on the future of organizations.

The study aimed at revealing the pattern of appraising the performance of human resource management for the study sample, and whether it was qualified to lead the ministry towards the organizational success, for this purpose two main hypotheses were formulated: 1) there is a positive significant correlation between both variables: performanc

... Show More
View Publication Preview PDF
Crossref