Preferred Language
Articles
/
OBdc4I4BVTCNdQwCYFl_
Absorption Coefficient of a Double-Layer Inhomogeneous Micro-perforated Panel Backed with Multiple Cavity Depths
...Show More Authors

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.

Scopus Clarivate Crossref
View Publication
Publication Date
Thu Jun 01 2023
Journal Name
Baghdad Science Journal
Design and construction of anair pollution detection system using a laser beam and absorption spectroscopy
...Show More Authors

Air pollution is one of the important problems facing Iraq. Air pollution is the result of uncontrolled emissions from factories, car exhaust electric generators, and oil refineries and often reaches unacceptable limits by international standards. These pollutants can greatly affect human health and regular population activities. For this reason, there is an urgent need for effective devices to monitor the molecular concentration of air pollutants in cities and urban areas. In this research, an optical system has been built consisting of aHelium-Neonlaser,5mWand at 632.8 nm, a glass cell with a defined size, and a power meter(Gentec-E-model: uno) where a scattering of the laser beam occurs due to air pollution. Two pollutants were examin

... Show More
View Publication Preview PDF
Scopus (8)
Crossref (1)
Scopus Crossref
Publication Date
Thu Jun 30 2016
Journal Name
Al-kindy College Medical Journal
Evaluation Of Risk Factors In Perforated Acute Appendicitis In Al-Kindy Teaching Hospital
...Show More Authors

Background: Appendectomy is still one of the most commonly performed emergency surgical procedures worldwide.Avoiding delays in the diagnosis in these patients may play a role in reducing observed morbidity.Aim of study:To analyze the clinico-pathological profile and outcomes of patients undergoing emergency appendectomies to determine risk factors influencingcomplicaions.Type of the study: A prospective analytic studyPatients and Methods: The study involves 108 patients underwent emergency appendectomies at Al-kindy teaching hospital from April 2014 to March 2015. Appendicitis was categorized into two groups perforated andnonperforatedappendicities. A comparison between them was made in regard to Gender, Age, clinical presentation, inve

... Show More
View Publication Preview PDF
Publication Date
Wed Mar 10 2021
Journal Name
Baghdad Science Journal
Simole matimatical technique in leaser cavity design and manufacturing
...Show More Authors

In this research design was treated gap laser mathematically and practically Bashaddam model Raasi simple and new and we have found that there is a good match in the practical and theoretical results

View Publication Preview PDF
Publication Date
Fri Jun 25 2021
Journal Name
International Journal Of Drug Delivery Technology
Oral Cavity Microbiome as Infectious Agents: Iraqi Kocuria Rosea
...Show More Authors

Scopus (1)
Scopus
Publication Date
Mon Apr 01 2024
Journal Name
Heliyon
Ground effect of an inverted double element wing diffuser on a sedan car
...Show More Authors

View Publication
Scopus (4)
Crossref (3)
Scopus Clarivate Crossref
Publication Date
Mon Jun 01 2015
Journal Name
International Journal Of Advanced Research In Computer Science And Software Engineering
Performance Comparison of Transport Layer Protocols
...Show More Authors

Transport layer is responsible for delivering data to the appropriate application process on the host computers. The two most popular transport layer protocols are Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). TCP is considered one of the most important protocols in the Internet. UDP is a minimal message-oriented Transport Layer protocol. In this paper we have compared the performance of TCP and UDP on the wired network. Network Simulator (NS2) has been used for performance Comparison since it is preferred by the networking research community. Constant bit rate (CBR) traffic used for both TCP and UDP protocols.

View Publication
Publication Date
Mon Sep 10 2018
Journal Name
Iraqi Journal Of Physics
Thermal conductivity and diffusion coefficient of polymer blend 80%EP/20%UPE reinforced with sand particles
...Show More Authors

New polymer blend with enhanced properties was prepared from (80 %) epoxy resin (Ep), (20%) unsaturated polyester resin (UPE) as a matrix material. The as-obtained polymer blend was further reinforced by adding Sand particles of particle size (53 μm) with various weight fraction (5, 10, 15, 20 %). Thermal conductivity and sorption measurements are performed in order to determine diffusion coefficient in different chemical solutions (NaOH, HCl) with concentration (0.3N) after immersion for specific period of time (30 days). The obtained results demonstrate that the addition of sand powder to (80%EP/20%UPE) blend leads to an increase of thermal conductivity, with an optimum/minimum diffusion coefficient in (HCl)/(NaOH), respectively.

View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Sat Jul 01 2023
Journal Name
Heliyon
Effect of plasma surface treatment of three different CAD/CAM materials on the micro shear bond strength with resin cement (A comparative in vitro study)
...Show More Authors

Objectives: This study aimed to evaluate and compare the effect of plasma treatment versus conventional treatment on the micro shear bond strength (μSBS), surface roughness, and wettability of three different CAD/CAM materials. Materials and methods: Sixty cylindrical specimens (5 mm diameter ×3 mm height) were prepared from three different CAD/CAM materials: Group A: Zirconia, Group B: Lithium disilicate, and Group C: Resin nano-ceramic. Each group was subdivided into two subgroups according to surface treatment used: Subgroup I: Conventional treatment, zirconia was sandblasted with Al2O3, while lithium disilicate and resin nano-ceramic were etched with hydrofluoric acid. Subgroup II: Plasma treatment, the surface of each material was tr

... Show More
View Publication Preview PDF
Scopus (19)
Crossref (13)
Scopus Clarivate Crossref
Publication Date
Fri Aug 07 2020
Journal Name
Key Engineering Materials
Compressive Strength and Shrinkage Behavior of Concrete Produced from Portland Limestone Cement with Water Absorption Polymer Balls
...Show More Authors

From the sustainability point of view a combination of using water absorption polymer balls in concrete mix produce from Portland limestone cement (IL) is worth to be perceived. Compressive strength and drying shrinkage behavior for the mixes of concrete prepared by Ordinary Portland Cement (O.P.C) and Portland limestone cement (IL) were investigated in this research. Water absorbent polymer balls (WAPB) are innovative module in producing building materials due to the internal curing which eliminates autogenous shrinkage, enhances the strength at early age, improve the durability, give higher compressive strength at early age, and reduce the effect of insufficient external curing. Polymer balls (WAPB) had been used in the mixes of thi

... Show More
Publication Date
Sat May 01 2010
Journal Name
Journal Of Baghdad College Of Dentistry
Comparison of microleakage Restorative Dentistry Comparison of microleakage in three different retrograde cavity preparations with Mineral Trioxide Aggregate as filling material
...Show More Authors

Background: The apical seal is the single most important factor in determining the success of surgical endodontics, the aim of this study was to compare the sealing ability of Mineral Trioxide Aggregate in three different cavity designs. Materials and Methods: Thirty extracted human single-rooted teeth were divided into three groups of ten teeth per group, a retrograde cavity preparation was carried out using a low speed handpiece and round bur with parallel walls in the first group, ultrasonic retrotip and unit in the second group and a low speed handpiece with a carbide inverted cone bur with undercuts in the third group, all the cavities were filled with MTA. microleakage was measured by dye penetration technique using methylene blue. Re

... Show More
Preview PDF