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Absorption Coefficient of a Double-Layer Inhomogeneous Micro-perforated Panel Backed with Multiple Cavity Depths
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Double-layer micro-perforated panels (MPPs) have been studied extensively as sound absorption systems to increase the absorption performance of single-layer MPPs. However, existing proposed models indicate that there is still room for improvement regarding the frequency bands of absorption for the double-layer MPP. This study presents a double-layer MPP formed with two single MPPs with inhomogeneous perforation backed by multiple cavities of varying depths. The theoretical formulation is developed using the electrical equivalent circuit method to calculate the absorption coefficient under a normal incident sound. The simulation results show that the proposed model can produce absorption coefficient with wider absorption bandwidth compared with the conventional double- and even triple-layer MPPs. The bandwidth can be increased to higher frequency by decreasing the cavity depth behind a sub-MPP with small hole diameter and a high perforation ratio, and to lower frequency by increasing the cavity depth behind a sub-MPP with large hole diameter and a small perforation ratio. The experimental data, measured by impedance tube, are in good agreement with the predicted results.

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Publication Date
Wed May 10 2017
Journal Name
Australian Journal Of Basic And Applied Sciences
Photometric Viewpoint to the Structure of Spiral Galaxy NGC 3351 with griz-Filters
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The term ‘photometry’ refers to the accurate determination of the apparent brightness of an astronomical object. Until roughly 1980, nearly all astronomical photometry was done by means of analog measurements of photographic plates, or by analog or digital (photon-counting) techniques with photomultipliers. These photometers produced brightness readings which were typically displayed on dials, plotted on strip charts or printed on strips of paper, and it was often quite practical to analyse these raw data with pencil, paper and a slide rule or table of logarithms. However, during the late 1970s electronic area detectors for astronomy became more advanced: first, for a brief period, television-type cameras were employed, but these were s

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Publication Date
Sun Jun 03 2012
Journal Name
Baghdad Science Journal
Histological study of Culex pipiens pipiens larvae and adults infected with Beauveria bassiana
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This study aimed to show the histological changes that 0ccured in Culex pipiens pipiens larvae and adults infected with Beauveria bassiana . The 4th instar larvae and adult mosquitoes were infected with B.bassiana in 10-4 spore/ml dilution, after 96 hours histological section was studied showing that the fungi infected all the body parts specially Cuticle , Epiderms, fat bodies and midgut. After 120 hours of exposure to the fungi the insect have a white appearance and covered with a thick coat of hyphea. Thus study shows biological control of B .bassiana on mosquitoes.

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Publication Date
Sat Oct 01 2011
Journal Name
Journal Of Engineering
THERMAL BUCKLING OF RECTANGULAR PLATES WITH DIFFERENT TEMPERATURE DISTRIBUTION USING STRAIN ENERGY METHOD
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By using governing differential equation and the Rayleigh-Ritz method of minimizing the total potential energy of a thermoelastic structural system of isotropic thermoelastic thin plates, thermal buckling equations were established for rectangular plate with different fixing edge conditions and with different aspect ratio. The strain energy stored in a plate element due to bending, mid-plane thermal force and thermal bending was obtained. Three types of thermal distribution have been considered these are: uniform temperature, linear distribution and non-linear thermal distribution across thickness. It is observed that the buckling strength enhanced considerably by additional clamping of edges. Also, the thermal buckling temperatures and

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Publication Date
Thu Jan 07 2016
Journal Name
Ibn Al-haitham Jour. For Pure & Appl. Sci.
Determination of Some Trace Element Levels in Iraqi Male patients with Colorectal Cancer
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Alterations of trace element concentrations adversely affect biological processes and could promote carcinogenesis. Trace element deficiency or excess is implicated in the development or progression of some cancers like colorectal cancer. The aim of the present study was to compare the serum copper (Cu) and zinc (Zn) concentrations in patients with colorectal cancer from Iraqi male patient with those of healthy subjects. During the period of March 2015 until august 2015, a total of 25 patients with metastatic colon cancer and 20 healthy volunteers were enrolled from the Al-Kadhimia Teaching Hospital after the diagnosis using a histopathological examination for the malignant tumor; their age was between (38-60) years. Higher levels o

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Publication Date
Tue Dec 05 2023
Journal Name
Baghdad Science Journal
Antifungal Potential of Cladosporium sp. (Endophytic fungi) Associated with Olea europaea L. Leaves
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In the leaves of Olea europaea L. Olive trees an endophytic fungus was discovered. Cladosporium sp. was identified to be the fungus based on its morphological characteristics and nuclear ribosomal DNA ITS sequence analysis and was registered in NCBI as the Cladosporium genus has been registered under the number (0P939922.1) The species was not specified, and it was considered of unknown species after comparing it to global isolates. In comparison to olive leaf extract, Cladosporium sp. including total flavonoid, total phenolic, total terpenoid, and total saponins, Which were 121.9%, 198.1%, 89.13%, and 29.87 % respectively compared to its content in olive leaf extract, which was 61.54 %, 67.88 % , 17.1

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Publication Date
Sat Apr 15 2023
Journal Name
Iraqi Journal Of Science
Real-Time PCR Detection of Respiratory Syncytial virus (RSV) among Adults with Pneumonia
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This study aimed to confirm the presence of RSV using real-time PCR in nasal
and throat swabs which had no visible cytopathic effect in tissue culture technique
from adults of moderate-to-severe pneumonia with influenza-like illness. Results of
real-time RT-PCR found that viral RNA in 11.63% (5/43) of adult with pneumonia
and flu-like illness symptoms. A significant incidence of RSV infection in Dec. and
Jan. 2014 was appeared among patients aged more than 45 years. The results
showed that viral load significantly associated with disease severity. In conclusion,
multiplex RT-PCR is recommended to diagnose RSV and influenza viruses in
winter season in older patients with pneumonia and can decrease sever illness in

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Publication Date
Sat Nov 28 2020
Journal Name
Iraqi Journal Of Science
Serum Level of Interleukin-35 in Patients with Chronic Hepatitis B Virus Infection
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Interleukin-35 (IL-35) is a new member of IL-12 family of cytokines, and its role in pathogenesis of hepatitis B virus (HBV) infection has been recently suggested. Accordingly, a case-control study was conducted during June - October 2018 to determine IL-35 serum level in Iraqi patients with chronic HBV infection. The results revealed that IL-35 level was significantly decreased in patients as compared to control (163 vs. 301 pg/ml; p < 0.001). However, such decreased level was more pronounced in patients at the age groups < 40 and 40 – 50 years (165 and 145 pg/ml, respectively) as compared to the corresponding age groups in control (482 and 234 pg/ml, respectively). In the case of gender groups, both male

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Publication Date
Wed Feb 02 2022
Journal Name
Journal Of University Of Shanghai For Science And Technology
Antiparasitic activity of Artemether and combination Artemether with Artemisinin against Leishmaniasis, in vitro.
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The Leishmania donovani parasite causes visceral leishmaniasis (VL), an acute and fatal form of leishmaniasis. Because traditional therapy alternatives, such as glucantime and other pentavalent medicines, are toxic and have side effects, new treatments with fewer negative effects are needed. Only a handful of drugs are clinically beneficial to treatments of the disease, but considerable limitations threaten their very usage. Novel, safe, and efficient drugs, including those against antimalaria and leishmaniasis co-infections, are so essential. Artemether (ATM) is an Artemisinin derivative that has been demonstrated to be useful in the treatment of malaria and, more recently, leishmaniasis. The current research was carried out to evaluate th

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Publication Date
Wed Feb 05 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Assessment of serum and salivary ceruloplasmin level in patients with oral lichen planus
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Background: Oxidative stress is a deleterious process that can be an important mediator of damage to cell structures and consequently various disease states. Exposure to free radicals from a variety of sources has led organisms to produce a series of defense mechanisms. The antioxidant ceruloplasmin is a copper-containing ferroxidase that can oxidize ferrous iron (Fe2+) to its nontoxic ferric (Fe3+) form. Ferrous iron (Fe2+) is extremely damaging because of its ability to generate toxic free radicals. Oral lichen planus (OLP) is a chronic inflammatory oral mucosal disease of unknown etiology. Previous studies reported that reactive oxygen species may be involved in the pathogenesis of lichen planus. The aim of this study was to estimate the

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Publication Date
Fri Jan 26 2024
Journal Name
Iraqi Journal Of Science
The Dynamics of Holling Type IV Prey Predator Model with Intra- Specific Competition
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In this paper a prey-predator model involving Holling type IV functional response
and intra-specific competition is proposed and analyzed. The local stability analysis of
the system is carried out. The occurrence of a simple Hopf bifurcation is investigated.
The global dynamics of the system is investigated with the help of the Lyapunov
function and poincare-bendixson theorem. Finally, the numerical simulation is used to
study the global dynamical behavior of the system. It is observed that, the system has
either stable point or periodic dynamics.

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