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Impact of using Double Layers Perforated Liners on the Acoustic Treatments of the Combustor Systems
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The response of the combustor’s liner to the air-flow that passes through it is the key reason for the combustion chambers noise, hence the instabilities of those chambers that decreases the mechanical efficiency of such sections, by increased its mechanical vibrations, which increases the failure rate created during originating of the cracks spreading by the shakes producing by the series of high-level frequencies. Accordingly, any work debating the impact of the context of liners in the combustion chamber can provide grasping for the combustion noise generated by the undesirable vibrations, and benefits the industrial firms to design an ideal production procedure which increases the lifespan of the combustor. The goal of this work is to examine the influence of the acoustic treatment using a double layers cylindrical perforated liner on the acoustic transmission loss of gas turbines. The liners layout influences on this acoustic parameter was examined using an experimental data gained by the insertion of a full scale single and double patterns of perforated liners into the unique large scale acoustic wind tunnel at the acoustic research center at Hull University. The experimental tests under-designed acoustic signals were established firstly using 0m/s air cross-flow velocity, then by changed velocities with interval 5m/s ranging between 10m/s to 25m/s. MATLAB script was used to simulate, analyze, and figure out the data collected the insertion of single and double layer patterns of the perforated liner. The experiments demonstrated that, if the perforation acoustic treatments are applied, the acoustic transmission loss will decrease, particularly obvious at higher level frequencies. Further, the results exposed that the air tunnel with the insertion of the liner with double layers reveals an improved perforation acoustic treatment.

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Publication Date
Thu Apr 30 2026
Journal Name
International Journal Of Engineering Pedagogy (ijep)
The Impact of Intelligent Adaptive Learning on Flexible Thinking and Academic Achievement for Undergraduate Students
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In the knowledge society, artificial intelligence (AI) forms a cornerstone of global education. This quasi-experimental study examines the impact of an Intelligent Adaptive Learning Strategy (IALS) on flexible thinking (FT) and academic achievement among 60 3rd-year undergraduate students at the College of Education/University of Baghdad (experimental n = 30; control n = 30). The IALS was implemented via an AI-supported educational platform, while the control group received conventional instruction. Post-test intervention assessments included an FT test (10 items, content validity = 0.89, Cronbach’s α = 0.87) and an achievement test (10 objective items, α = 0.85). Results revealed statistically significant superiority of the exp

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Publication Date
Sun Mar 15 2020
Journal Name
Journal Of Baghdad College Of Dentistry
The impact of dental environment stress on caries experience, salivary flow rate and uric acid
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Background: Several pathologies of the oral cavity have been associated with stress. Dental students need to gain assorted proficiencies as theoretical knowledge, clinical proficiencies, and interpersonal dexterity which is accompanied with high level of stress. Uric acid is the major antioxidant in saliva. The aim of this study is to assess the dental caries experience among dental students with different levels of dental environment stress in relation to physicochemical characteristics of whole unstimulated saliva.

Materials and Methods: the total sample is composed of 300 dental students (73 males, 227 female) aged 22-23 years old, from collage of dentistry / university of Baghdad, from the 4t

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Publication Date
Sun Jan 01 2023
Journal Name
Aip Conference Proceedings
Impact of geographical locations of the water treatment plants in Baghdad City on quality of supplied water
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In this study, the water treatment plants located on the Tigris River within Baghdad city were subjected to qualitative and quantitative assessments. Based on location, the plants from upstream to downstream are Al-Karkh, East Tigris, Al-Karamah, Al-Wathbah, Al-Wehdah, Al-Kadiseyah, Al-Dora, and Al-Rashid. Data from 2009 to 2020 on the turbidity, total dissolved solids, Alkalinity, hardness, chloride, calcium, and temperature were used in the qualitative assessment while data on the treated water production and population served were used in the quantitative assessment. The above Data was acquired from the Municipality of Baghdad. The turbidity was mainly used as a fair gauge to assess the performance of the water treatment plants in Baghda

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Publication Date
Sun Dec 27 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Analysis of factors affecting the desire of the customer and their impact on the market share in a competitive market National Insurance Company
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The research aims to identify the factors affecting the customer and their impact desire for market share in a competitive market National Insurance Company, where he was after the tremendous developments that have taken place in the insurance sector, crowded markets, private companies and the intensified competition among those companies on one side and public sector companies, including national insurance company on the other hand, increased attention and study in a big way the customer and the factors influencing the desire. As the national insurance company ascertains its targets once the sale of insurance documents only, but by knowing the tendencies and aspirations of current and prospective customers a way that helps to strengthen

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Publication Date
Mon Feb 12 2024
Journal Name
Mustansiriyah Journal Of Sports Science
The impact of the use of numbered head and brainstorming strategies to learn handspring on the Vault table in artistic gymnastics for Men
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The aim of the study was to identify the use of the strategies of numbered heads and brainstorming in learning handspring on the Vault table in artistic gymnastics for Men for the third grade students in the collage of Physical Education and Sport Sciences, as well as to identify the best group among the three research groups (number of heads numbered,, brainstorming strategies And the traditional style group) to learn the skill under study. Using the experimental method, the research subject included the third grade students in the collage of Physical Education and Sports Sciences / University of Baghdad, and randomly by lot, 12 students were selected for each of the three research groups. The study consisted of the arithmetic mean

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Publication Date
Mon Aug 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
The impact of production elements responsible on the environmental management system requirements of ISO 14001 - 2004 field study in the North Gas Company
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Abstract

         Most of the industrial organization in the world became suffering from the problem of the pollution of the poisonous chemicals things, this urged to depend on the principle of the responsible production, because it has the positive role by dealing with these chemical things and to safe the health of the society, due to the main goal of this study is to restrict the role responsible production in accomplishing the system of the environmental management through an actual study in the northern gas company in Kirkuk province, the topic has acquired a big importance bacause there were a limited number of studies and res

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Publication Date
Sat Mar 01 2014
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The exercise of citizenship behaviors and their impact on customer loyalty: Analytical study from the standpoint of employees in the National Insurance Company
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The exercise of citizenship behaviors and their impact on customer loyalty (An analytical study from the perspective of workers in the National Insurance Company).

The Research aims to find out the degree of customers National Insurance company for customer citizenship behavior and its impact on the level oh loyalty from the perspective of employess in the company, as well as the statement of the differences in the answers of employees according to their personality traits. To achieve the goals of research has been the use of the questionnaire as a tool for the collection and distribution of data on a sample of (90) individuals, as was the use of statistical program (SPSS) in the process of statistical analysis methods (mean, sta

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Publication Date
Mon Mar 07 2022
Journal Name
Journal Of Educational And Psychological Researches
The impact of the Roundtable and Self-Questioning strategies on achievement and self-efficacy For students of the Faculty of Education in the subject of research curricula
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The current research aims to identify "the impact of the round table strategies and the question of self-achievement and self-efficacy among students of the Faculty of Education in research methodology course.” The research sample consisted of (75) male and female-third stage students in the department of Life Sciences / College of Education for Pure Sciences / University of Dhi Qar for the academic year (2018-2019. The researcher adopted the experimental approach to achieving the study objectives. The researcher prepared two tools: the achievement test and the self-efficacy scale were applied to the collected sample to obtain the needed data. The result showed that there was a statistically significant difference at the level (0.05) b

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Publication Date
Fri Dec 01 2023
Journal Name
Political Sciences Journal
Impact of the Rising of China in Restructuring the International System
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It is no secret to everyone that the Arab individual suffers from poor self-awareness and political awareness, which made the state and the importance of its existence and preserving its institutions not among his interests, which made researchers wonder about the possibility of strengthening it and the extent of its impact on the future of building the contemporary Arab state. So, the study attempts to addressing the issue of community awareness and its impact on building the state through a clear intellectual vision that blended what is social and political to define the concept of community awareness and highlight its importance and role as a basic pillar in shaping and building modern Arab countries in the Arab world and ways to enha

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Publication Date
Thu Apr 30 2020
Journal Name
Journal Of Economics And Administrative Sciences
The impact of empowerment strategies on the characteristics of work enrichment An exploratory research to the views of a sample of the leaders of the Ministry of Oil in Iraq
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The study aimed to investigate the relationship between empowerment strategies and their impact on the success of enrichment work, it included the dimensions of empowerment strategies (power, knowledge, information, rewards), The dimensions of Job enrichment are (Skill variety, Task identity, Task significance, Autonomy, Feedback). The study was conducted at the headquarters of the Iraqi Oil Ministry in Baghdad and was based on a sample of the leadership of the ministry of managers consisting of 215 people. The data were collected using the questionnaire method based on scientific standards adopted in previous st

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