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.
In the present study, magnet silica-coated Ag2WO4/Ag2S nanocomposites (FOSOAWAS) were fabricated via a multistep method to address the drawbacks related to single photocatalysts (pure Ag2WO4 and pure Ag2S) and to clarify the significant influence of semiconductor heterojunction on the enhancement of visible-light-driven organic degradation. Different techniques were performed to investigate the elemental composition, morphology, magnetic and photoelectrochemical properties of the fabricated FOSOAWAS photocatalyst. The FOSOAWAS photocatalyst (1 g/L) exhibited excellent photodegradation efficiency (99.5%) against Congo red dye (CR = 20 ppm) after 140 min of visible-light illumination. This result confirmed the ability of the heterojunction be
... Show MoreIn Iraq; there is a great demand for handling some epidemic diseases such as hyperglycemia and hyperlipidema through searching some medical plant extracts which the country is rich with and contains an important phytochemicals that may solve the incidence of such cases. Aloe vera that cultivated in Iraq, is known to be rich with biological active constituents. The aim of the present study; the plant gel extract was subjected to treat an induced diabetic lab mice through injecting streptozotocin dose with high fatty food to elevate lipid profile before induction of the gel oral treatment of the plant. In the study results: the oral administration of A.ver
... Show MoreThe study was carried out to determine the cytotoxic, antioxidant and gastro-protective effect of ethyl-4-[(3,5-di-tert-butyl-2-hydroxybenzylid ene)amino] benzoate (ETHAB) in rats.
Through research and research in the creative composition in the poetry of Zafer-Alhaddad it turned out to be superior in its systems, especially that he chose a linguistic and verbal texture accompanied by a cultural dictionary full of creativity and beauty helped this culture arrangement reflects the poetically wonderful and beautiful custom led to the harmony of colors and bodies painted by the poet brush the creative artist evaluates the metaphorical and metaphorical relations that would explain the poets idea, most of which were inspired by the wonderful spirit of nature, its beautiful landscapes and bright colors, especially that we do not forget the beautiful colors and the aesthetic touch that created a fascinating musical intera
... Show MoreTwo series of 1,n-alkylene glycol di [4{N(T-thiazolylazoÂ
nrethinyl)}2-metho y] phenyl ether and I ,n-alkylene glycol di[4{N(r-benzo-thiazolylazomethinyl)}2-methoxy]phenyl ether were synthesize-d via rea tions 2-aminothiazole and 2-aminobenzothiazole with dialdehyde • (which are synthesized from .reaction vanil.lin with
l ,n-dibromo or ehloro. alkane in the basic me'dia ) . &nb
... Show MoreAbstract: Two different shapes of offset optical fiber was studied based on coreless fiber for refractive index (RI)/concentration (con.) measurement, and compare them. These shapes are U and S-shapes, both shapes structures were formed by one segment of coreless fiber (CF) was joined between two single mode (SMF) lead in /lead out with the same displacement (12.268µm) at both sides, the results shows the high sensitive was achieved in a novel S-shape equal 98.768nm/RIU, to our knowledge, no one has ever mentioned or experienced it, it’s the best shape rather than the U-shape which equal 85.628nm/RIU. In this research, it was proved that the offset form has a significant effect on the sensitivity of the sensor. Addi
... Show MoreThe research aims to identify the effect of teaching according to the augmented reality on the technique of the visual thinking skills among scientific fifth-grade students in a biology course. In order to achieve the goal of the research, the researcher adopted the experimental approach with the partial set of the two equal groups with the dimensional test of visual thinking skills, The research population represented all the scientific students of the fifth grade for morning government schools affiliated to the General Directorate of Education of Baghdad / Karkh II, alshakerin preparatory for boys was chosen intentionally, in which two groups were chosen for this study, one group is chosen randomly as the control group via lottery, whe
... Show MoreTemperature predicting is the utilization to forecast the condition of the temperature for an upcoming date for a given area. Temperature predictions are done by gathering quantitative data in regard to the current state of the atmosphere. In this study, a proposed hybrid method to predication the daily maximum and minimum air temperature of Baghdad city which combines standard backpropagation with simulated annealing (SA). Simulated Annealing Algorithm are used for weights optimization for recurrent multi-layer neural network system. Experimental tests had been implemented using the data of maximum and minimum air temperature for month of July of Baghdad city that got from local records of Iraqi Meteorological O
... Show MoreThe stratigraphic sequence of Cenomanian-Early Turonian is composed of Ahmadi, Rumaila, and Mishrif formations in the Rifai, Noor and Halfaya Oil Fields within the Mesopotamian Zone of Iraq, which is bounded at top and bottom by unconformity surfaces. The microfacies analysis of the study wells assisted the recognition of five main environments (open marine, basinal, shallow open marine, Rudist biostrome, and lagoon); these microfacies were indicative of a normal lateral change facies from shallow water facies to deeper water and open marine sediments.
Ahmadi Formation (Early Cenomanian) is characterized by open marine sediments during the transgressive conditions, and would be
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