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Wideband sound absorption of a double-layer microperforated panel with inhomogeneous perforation
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Micro-perforated panel (MPP) absorber is increasingly gaining popularity as an alternative sound absorber in buildings compared to the well-known synthetic porous materials. A single MPP has a typical feature of a Helmholtz resonator with a high amplitude of absorption but a narrow absorption frequency bandwidth. To improve the bandwidth, a single MPP can be cascaded with another single MPP to form a double-layer MPP. This paper proposes the introduction of inhomogeneous perforation in the double-layer MPP system (DL-iMPP) to enhance the absorption bandwidth of a double-layer MPP. Mathematical models are proposed using the equivalent electrical circuit model and are validated with experiments with good agreement. It is revealed that the DL-iMPP produces a wider half-absorption bandwidth compared to the conventional homogeneous double-layer MPP. The absorption bandwidth to higher frequencies can be effectively controlled by reducing the air cavity between the iMPPs and to the lower frequencies by increasing the back cavity depth at the second layer.

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Publication Date
Sat Jan 31 2015
Journal Name
Journal Of Al-qadisiyah For Pure Science
synthesis ,spectral studies and antimicrobial evalution of 6,6-(1,2-benzenediazo)bis(3-amino benzoic acid) complexes with some metal ions
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Publication Date
Wed May 24 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Science
Direct and Indirect Spectrophotometric Determination of Paracetamol in Pharmaceutical Preparations By Oxidative Coupling With p-Amino-2-hydroxy Sodium Benzoate
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New simple and sensitive spectrophotometric methods for the determination of paracetamol in aqueous medium were developed. The first method is based on coupling of paracetamol with p-amino-2-hydroxy sodium benzoate (AHB) in the presence of sodium periodate, as oxidizing agent, to form a brownish-orange compound which shows a λmax at 470 nm. The molar absorptivity (εmax) of the colored product was found to be (3371) l. mole1. cm-1 and Sandel’s index 0.0449 μg. cm-2. The method follows Beer’s law in the concentration range of 12.5-500.0 μg of paracetamol in a final volume of 25 ml (0.5-20.0) μg. ml-1 with relative standard deviation percent (RSD%) ranged between 0.26-4.71% and accuracy, expressed by recovery percent, 95-106% for five

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Publication Date
Wed Apr 19 2023
Journal Name
Lasers In Medical Science
Immunohistochemistry technique for effect of gold nanoparticles, laser, and photodynamic therapy on FoxP1 level in infected mice with mammary adenocarcinoma
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Publication Date
Sun Mar 04 2012
Journal Name
Baghdad Science Journal
Synthesis and Spectral Studies of ZnII,CdII and HgII Complexes with 5-(2-Benzoic acid azo)-8-hydroxy quinoline Ligand
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Coupling reaction of 2-amino benzoic acid with 8-hydroxy quinoline gave bidentate azo ligand. The prepared ligand has been identified by Microelemental Analysis,1HNMR,FT-IR and UV-Vis spectroscopic techniques. Treatment of the prepared ligand with the following metal ions (ZnII,CdII and HgII) in aqueous ethanol with a 1:2 M:L ratio and at optimum pH, yielded a series of neutral complexes of the general formula [M(L)2]. The prepared complexes have been characterized by using flame atomic absorption, (C.H.N) Analysis, FT-IR and UV-Vis spectroscopic methods as well as conductivity measurements. The nature of the complexes formed were studied following the mole ratio and continuous variation methods, Beer's law obeyed over a concentration ra

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Publication Date
Tue Jan 02 2024
Journal Name
Turkish Archives Of Pediatrics
Evaluation of Decayed, Missing Due to Caries, and Filled Teeth Index in Children with Phenylketonuria in Comparison to Normal Population
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Publication Date
Sun Mar 02 2014
Journal Name
Baghdad Science Journal
Kinetic and thermodynamic Studies Of Alanine Aminopeptidase(AAP) Isoenzymes I,II Partially Purified From Patient's Urine With Urinary Tract Cancer
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The activity of Alanine aminopeptidase( AAP ) was measured in the urine of healthy and urinary tract cancer patients , the results showed higher activity of (AAP) in patients compared to healthy . AAP was Purified from the urine of healthy and patients with urinary tract cancer by dialysis and gel filtration (Sephadex G – 50) and two isoenzymes of (AAP) were separated from urine by using ion-exchang resin (DEAE – Sephadex A – 50 ) in previous study. The kinetics studies showed that both isoenzymes I and II obeyed Michaelis – Menton equation . with optimal concentration of alanine-4-nitroanilide as substrate for isoenzymes I and II which was (2 x 10-3 mol/L ). The two isoenzymes obeyed Arrhenius equation up two 37° C and t

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Publication Date
Thu Feb 01 2018
Journal Name
Research Journal Of Pharmaceutical,biological And Chemical Sciense
correlation of serum tumor necrosis factor alpha and high sensitive c-reactive protein with clinical periodontal parameters in osteoarthritis patients
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Publication Date
Sun Sep 01 2013
Journal Name
Baghdad Science Journal
Synthesis and Theoretical Study of 4-(2-methyl-4-oxoquinazoline-3(4H)-yl) Benzoic acid with Some Transition Metal Ions
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New complexes of the type [ML2(H2O)2] ,[FeL2(H2O)Cl] and [VOL2] were M=Co(II),Ni(II) and Cu(II) ,L=4-(2-methyl-4-oxoquinazoline-3(4H)-yl) benzoic acid were synthesized and characterized by element analysis, magnetic susceptibility ,molar conductance ,FT-IR and UV-visible. The studies indicate that the L acts as doubly monodentate bridge for metal ions and form mononuclear complexes. The complexes are found to be octahedral except V(IV) complex is square pyrimde shape . The structural geometries of compounds were also suggested in gas phase by theoretical treatments, using Hyper chem-6 program for the molecular mechanics and semi-empirical calculations, addition heat of formation(?Hf ?) and binding energy (?Eb)for the free ligan

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Publication Date
Tue Aug 05 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Antibacterial Effect of Aqueous and Alcoholic Propolis Extracts on Aggregatibacter Actinomycetemcomitans in Patients with Chronic Periodontitis (An In-vitro Study)
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Background: Propolis has received great interest because of its wide range antimicrobial activity. Propolis also called (bee glue) due to its collection by (Apismellifera) honeybees from various plants resinous substance. The aim of this study was to determine the antibacterial effect of propolis extracts (aqueous and alcoholic) on anaerobic periodontal pathogen namely Aggregatibacteractinomycetemcomitans. Materials and Methods: Strains of Aggregatibacter actinomycetemcomitans wasisolated from pockets of systemically healthy patients aged between 35-55 years old suffering from chronic periodontitis with pocket depths of 5-6 mm, the bacteria cultured on special blood Agar plates solid media. Propolis was extracted by using water and alcohol.

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Publication Date
Wed Aug 10 2016
Journal Name
Fourth International Conference On Genetics And Scientific Environment. Cairo / Arab Republic Of Egypt For The Period From July 23 To 30
Efficacy of Arbuscular mycorrhiza (AM) in inducing non-enzymatic antioxidants in tomato leaves infected with Fusarium oxysporum f. sp. Lycopersici.
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