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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
Sun Jul 01 2007
Journal Name
Journal Of The Faculty Of Medicine Baghdad
A Comparison between Topical application of Calcipotriene, Clobetasol and a combination regime of the two drugs in the treatment of Iraqi Patients with Psoriasis Vulgaris
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Back ground: Psoriasis is a chronic relapsing disorder with no life long cure, many systemic and topical modalities are available, one of these topical modalities is the vitamin D analogue
(calcipotriene) which is widely used recently to treat psoriasis and many other skin problems.
Aim of the study: Is to compare the safety, the efficacy and the tolerability of tolerability of topical calcipotriene, topical clobetasol and both of them in combination in treating Iraqi patients with psoriasis vulgaris. (The first study in Iraq that uses calcipotriene ointment in treating psoriasis and comparing it with other known topical treatments that were commonly used to treat this problem).
Patients and methods A to

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Publication Date
Sat Sep 01 2007
Journal Name
Al-khwarizmi Engineering Journal
Free Convective Heat Transfer with Different Sections Lengths Placed at the Exit of a Vertical Circular Tube subjected to a Constant Heat Flux
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A free convective heat transfer from the inside surface of a uniformly heated vertical circular tube has been experimentally investigated under a constant wall heat flux boundary condition for laminar air flow in the ranges of RaL from 6.9108 to 5109. The effect of the different sections (restrictions) lengths placed at the exit of the heated tube on the surface temperature distribution, the local and average heat transfer coefficients were examined. The experimental apparatus consists of aluminum circular tube with 900 mm length and 30 mm inside diameter (L/D=30). The exit sections (restrictions) were included circular tubes having the same inside diameter as the heated tube but with different lengths of

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Publication Date
Wed Jan 02 2013
Journal Name
Journal Of The Faculty Of Medicine Baghdad
pneumonia in childern admitted with lower respiratory tract infections.... A hospital based study
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Summary:
Background: Pneumonia is a common form of lower respiratory tract infection (LRTI) in children under five years of age and it is the leading cause of morbidity and mortality in this age group. Early management is important in decreasing its complications and mortality.
Methods: A cross sectional study of 100 patients, their ages ranged from 2 months to 5 years. They were admitted to Children Welfare Teaching Hospital Medical City–Baghdad in a period from 7th of November 2010 to 5th of May 2011, suffering from Lower Respiratory Tract Infections (fever, cough and tachypnea) and classified into two groups according to chest radiograph (CXR) findings, those with a patch (pneumonia) and others with normal or hyper inflated CX

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Publication Date
Mon Jan 28 2019
Journal Name
Iraqi Journal Of Science
Dynamics and an Optimal Policy for A Discrete Time System with Ricker Growth
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The goal of this paper is to study dynamic behavior of a sporadic model (prey-predator). All fixed points of the model are found. We set the conditions that required to investigate the local stability of all fixed points. The model is extended to an optimal control model. The Pontryagin's maximum principle is used to achieve the optimal solutions. Finally, numerical simulations have been applied to confirm the theoretical results.

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Publication Date
Mon Nov 22 2021
Journal Name
Nanomaterials
Melting Enhancement in a Triple-Tube Latent Heat Storage System with Sloped Fins
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Due to the potential cost saving and minimal temperature stratification, the energy storage based on phase-change materials (PCMs) can be a reliable approach for decoupling energy demand from immediate supply availability. However, due to their high heat resistance, these materials necessitate the introduction of enhancing additives, such as expanded surfaces and fins, to enable their deployment in more widespread thermal and energy storage applications. This study reports on how circular fins with staggered distribution and variable orientations can be employed for addressing the low thermal response rates in a PCM (Paraffin RT-35) triple-tube heat exchanger consisting of two heat-transfer fluids flow in opposites directions throug

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Publication Date
Sat Jul 31 2021
Journal Name
Iraqi Journal Of Science
Studying the Chaotic Dynamics Using Rossler-Chua Systems Combined with A Semiconductor Laser
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     In this paper, two different chaotic dynamic systems are coupled using a semiconductor laser to produce a new chaotic system. These two chaotic systems are Rossler and Chua systems. X-dynamic of Rossler system was coupled optically using optical fiber as a carrier of signal with x, y, and z-dynamics of Chua system. The results were analyzed and the behavior of Chua system was found to be changing in time series which, in turn, changed the attractor. The Chua attractor was converted from double scroll to single scroll. The results obtained from connecting two different systems in chaotic behavior showed a remarkable increase in the bandwidth of Chua system. This increase in bandwidth opens up a wide field for many

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Publication Date
Wed Feb 08 2023
Journal Name
Iraqi Journal Of Science
Embedding a Digitized Watermark Upon Colored Image Using Wavelet Transform with Comparative Technique
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A special methodology for adding a watermark for colored (RGB) image is formed and adding the wavelet transform as a tool during this paper. The watermark is added into two components. The primary one is by taking the key that contain associate eight range from (0...7) every range in it determines the actual bit position in specific component of canopy image. If that bit is analogous to the bit in watermark, (0) are hold on within the Least Significant Bit (LSB) of the watermarked image; otherwise (1) are hold on. The other is that it will add multiple secret keys victimization shift and rotate operations. The watermark is embedded redundantly over all extracted blocks in image to extend image protection. This embedding is completed with

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Publication Date
Tue Jun 30 2015
Journal Name
Al-kindy College Medical Journal
Familial Pulmonary Alveolar Microlithiasis: A Rare Case Report with Emphasis on Imaging Findings
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ABSTRACT Pulmonary alveolar microlithiasis is rare infiltrative pulmonary disease characterized by intra-alveoli deposition of microliths. We present a familial case of an adult female with complaint of progressive shortness of breath on exertion. Chest radiograph showed innumerable tiny dense nodules, diffusely involving both lungs mainly the lower zones. High-resolution CT scan illustrated widespread intra-alveolar microliths, diffuse ground-glass attenuation areas and septal thickening predominantly in the basal regions. Chest radiograph is all that is needed for the diagnosis of this case but CT scan was done to demonstrate the extent and severity of this disease

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Publication Date
Wed Apr 20 2011
Journal Name
Journal Of Al-qadisiyah For Computer Science And Mathematics
Chaos in a harvested prey-predator model with infectious disease in the prey
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A harvested prey-predator model with infectious disease in preyis investigated. It is assumed that the predator feeds on the infected prey only according to Holling type-II functional response. The existence, uniqueness and boundedness of the solution of the model are investigated. The local stability analysis of the harvested prey-predator model is carried out. The necessary and sufficient conditions for the persistence of the model are also obtained. Finally, the global dynamics of this model is investigated analytically as well as numerically. It is observed that, the model have different types of dynamical behaviors including chaos.

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Publication Date
Thu Nov 02 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
A Study on Liqid- Liquid Etraction on Iron(III) With 2,5- Diphenyi Oxazole
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A study on  liquid- liquid extraction  of Iron (III) in Benzene has  been made. The effect of different parameters such as type of medium and time of equilibration,  concentration  of metal  ion, type of organic  solvent,  and effect of cations on distribution ratio of Iron (III). Has been studies the stoichiometry   of  the  extracted  species  determined   using  slope  analysis method and found to be (M:L) (1 :3).

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