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.
Appeared in the light of globalization growing convergence of the distances between the countries in world, this convergence is causing mixing of cultures to become culture is a universal one culture, There are positives and negatives of this mixing and mingling of cultures, consider Loss of cultural identity is one of the biggest negatives the Arab cultural infrastructure in general and Iraq in special. In addition consider subject to not keep the cultural identity is the most important Arab issues and dangerous to our Arab identity in various fields, including design and architecture, highlights here the subject of research on the impact of globalization on the identity of the interior spaces, cafés of Baghdadi, one of the historical
... Show MoreVitamins k is an important fat-soluble vitamin that can be obtained from plants, bacteria and animals and is necessary for the blood clotting. It plays a key function as a cofactor in the synthesizing of blood clotting proteins in the liver; recently, the interest for its functions in extra-hepatic tissue has increased. Vitamin k deficiency is usually caused by abnormal absorption rather than in the lack of vitamin in food. Apart from its impact on clotting, chronic subclinical deficiency of vitamin K maybe a risk factor for many diseases such as osteoporosis, atherosclerosis, cancer, insulin resistance, neurodegenerative diseases and others, while current food intake guidelines be focused on the daily dose necessary to avoid blood loss.
... Show MoreAcademia Open Vol 8 No 2 (2023): December DOI: 10.21070/acopen.8.2023.8087 . Article type: (Medicine)Impact of COVID-19 on Dental Students' Psychological Health Maryam Hameed Alwan, [email protected], (1) Department of Oral Diagnosis, College of Dentistry, Baghdad University, Iraq, Iraq (1) Corresponding author Abstract This study investigates the psychological impact of the COVID-19 pandemic on dental students at Baghdad University College of Dentistry. Conducted between December 2021 and January 2022, this cross-sectional survey aligns with ethical guidelines and the Helsinki Declaration. The study utilized Cochran's equation to determine a sample size of at least 400, ensuring a 95% confidence level with a 5% margin of e
... Show MoreThis study was undertaken to diagnose routine settling problems within a third-party oil and gas companies’ Mono-Ethylene Glycol (MEG) regeneration system. Two primary issues were identified including; a) low particle size (<40 μm) resulting in poor settlement within high viscosity MEG solution and b) exposure to hydrocarbon condensate causing modification of particle surface properties through oil-wetting of the particle surface. Analysis of oil-wetted quartz and iron carbonate (FeCO₃) settlement behavior found a greater tendency to remain suspended in the solution and be removed in the rich MEG effluent stream or to strongly float and accumulate at the liquid-vapor interface in comparison to naturally water-wetted particles. As su
... Show MoreThe study deals with reactivity insertion linear and non linear and/or Ramp reactivity expressed as a polynomial in time in the presence of two Feedback mechanisms, using the neutronic-thermohydraulic coupling in order to predict the neutron behavior as a function of time in terms of reactor power. Also, a comparative study has been achieved in the case of the presence of the feedback mechanisms. Insertion of Ramp reactivities in terms of polynomial in time to study the behavior of power and reactivity as a function of time in the presence of two feedback mechanisms (fuel and coolant) has been carried out and the results are displayed as plots, and showed this results corresponding with international results. The present study shows t
... Show MoreThe research aims to find out the impact of cognitive strategies in the mathematical competence of the students of the fourth scientific in the preparatory mahmoudiyah in the Directorate General of The Education of Karkh 2. A post-test of the mathematical competence prepared by (Jassim, 2018) was applied to the sample of (65) students, distributed into two groups of (33) students as experimental group and (32) students as a control group. The results found there are significant differences between the experimental group and the control group in testing the mathematical competence of students for the experimental group.
The research aims at identifying the importance of scientific research for researchers and in creating new knowledge، development and utilization of mental and cognitive energies and developed them with the ability to research، extrapolation، meditation and then conclusion. The information was collected by interviewing the Secretary-General of the Central Library and by distributing questionnaire forms to the (33) teaching staff of the College of Higher Education. The responses of the society were analyzed the result and the recommendations were the most important 1. Information specialist and all employees of the administrators and technicians in the centers of information sources (libraries) and in the field are considered scientific r
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