Preferred Language
Articles
/
ExcQs44BVTCNdQwCBVcS
Wideband sound absorption of a double-layer microperforated panel with inhomogeneous perforation
...Show More Authors

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.

Scopus Clarivate Crossref
View Publication
Publication Date
Wed Jan 08 2020
Journal Name
International Journal Of Advanced Science And Technology
The local stability of an eco-epidemiological model involving a harvesting on predator population
...Show More Authors

In this paper a prey - predator model with harvesting on predator species with infectious disease in prey population only has been proposed and analyzed. Further, in this model, Holling type-IV functional response for the predation of susceptible prey and Lotka-Volterra functional response for the predation of infected prey as well as linear incidence rate for describing the transition of disease are used. Our aim is to study the effect of harvesting and disease on the dynamics of this model.

View Publication
Scopus (3)
Scopus
Publication Date
Thu Dec 09 2021
Journal Name
Journal Of Polymer Research
A new generation of cable grade poly(vinyl chloride) containing heavy metal free modifier
...Show More Authors
Abstract<p>Many additives are used to improve the performance of cables in terms of increasing their flame retardancy, thermal stability, thermal conductivity, and other characteristics. Unfortunately, most of these additives contain heavy metals. Therefore, the main objective of this study is to introduce a material representing a new generation of environmentally friendly heavy metal-free stabilizers for cable grade poly(vinyl chloride) that can compete with traditional materials in terms of performance and distinctive properties. This unique additive is Oxydtron, a synthetic silicate or simply nanocement. The tests performed are rheological properties represented by a capillary rheometry analysis, limiting o</p> ... Show More
View Publication
Scopus (5)
Crossref (3)
Scopus Clarivate Crossref
Publication Date
Thu Oct 20 2016
Journal Name
Sociological Methods &amp; Research
Mean Monte Carlo Finite Difference Method for Random Sampling of a Nonlinear Epidemic System
...Show More Authors

In this article, a numerical method integrated with statistical data simulation technique is introduced to solve a nonlinear system of ordinary differential equations with multiple random variable coefficients. The utilization of Monte Carlo simulation with central divided difference formula of finite difference (FD) method is repeated n times to simulate values of the variable coefficients as random sampling instead being limited as real values with respect to time. The mean of the n final solutions via this integrated technique, named in short as mean Monte Carlo finite difference (MMCFD) method, represents the final solution of the system. This method is proposed for the first time to calculate the numerical solution obtained fo

... Show More
View Publication
Scopus (15)
Crossref (10)
Scopus Clarivate Crossref
Publication Date
Thu Dec 15 2022
Journal Name
Engineering, Technology & Applied Science Research (etasr)
Numerical Modeling of a Pile Group Subjected to Seismic Loading Using the Hypoplasticity Model
...Show More Authors

Various simple and complicated models have been utilized to simulate the stress-strain behavior of the soil. These models are used in Finite Element Modeling (FEM) for geotechnical engineering applications and analysis of dynamic soil-structure interaction problems. These models either can't adequately describe some features, such as the strain-softening of dense sand, or they require several parameters that are difficult to gather by conventional laboratory testing. Furthermore, soils are not completely linearly elastic and perfectly plastic for the whole range of loads. Soil behavior is quite difficult to comprehend and exhibits a variety of behaviors under various circumstances. As a result, a more realistic constitutive model is

... Show More
View Publication Preview PDF
Scopus (6)
Crossref (6)
Scopus Clarivate Crossref
Publication Date
Wed Nov 02 2022
Journal Name
Clinical Oral Investigations
Development of a remineralizing calcium phosphate nanoparticle-containing self-etching system for orthodontic bonding
...Show More Authors
Abstract<sec> <title>Objectives

This study aimed to incorporate hydroxyapatite nanoparticles (nHA) or amorphous calcium phosphate nanoparticles (nACP) into a self-etch primer (SEP) to develop a simplified orthodontic bonding system with remineralizing and enamel preserving properties.

Materials and Methods

nHA and nACP were incorporated into a commercial SEP (Transbond™ plus) in 7% weight ratio and compared with the plain SEP as a control. Shear bond strengths (SBS), enamel damage, and adhesive remnant index (ARI) scores were evaluated at 24 h

... Show More
View Publication
Scopus (12)
Crossref (11)
Scopus Clarivate Crossref
Publication Date
Sat Mar 30 2019
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Estimation of rock strength from sonic log for Buzurgan oil field: A Comparison study
...Show More Authors

It is very difficult to obtain the value of a rock strength along the wellbore.  The value of Rock strength utilizing to perform different analysis, for example, preventing failure of the wellbore, deciding a completion design and, control the production of sand.  In this study, utilizing sonic log data from (Bu-50) and (BU-47) wells at Buzurgan oil field.  Five formations have been studied (Mishrif, Sadia, Middle lower Kirkuk, Upper Kirkuk, and Jaddala) Firstly, calculated unconfined compressive strength (UCS) for each formation, using a sonic log method.  Then, the derived confined compressive rock strengthens from (UCS) by entering the effect of bore and hydrostatic pressure for each formation.  Evaluations th

... Show More
View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Sun Dec 01 2024
Journal Name
Journal Of Economics And Administrative Sciences
Nadaraya-Watson Estimation of a Circular Regression Model on Peak Systolic Blood Pressure Data
...Show More Authors

Purpose: The research aims to estimate models representing phenomena that follow the logic of circular (angular) data, accounting for the 24-hour periodicity in measurement. Theoretical framework: The regression model is developed to account for the periodic nature of the circular scale, considering the periodicity in the dependent variable y, the explanatory variables x, or both. Design/methodology/approach: Two estimation methods were applied: a parametric model, represented by the Simple Circular Regression (SCR) model, and a nonparametric model, represented by the Nadaraya-Watson Circular Regression (NW) model. The analysis used real data from 50 patients at Al-Kindi Teaching Hospital in Baghdad. Findings: The Mean Circular Erro

... Show More
View Publication Preview PDF
Crossref
Publication Date
Mon Apr 01 2019
Journal Name
Journal Of Oral And Maxillofacial Surgery
Pain Reduction in Extensive Apical Surgery of the Anterior Maxilla: A Comparative Clinical Study
...Show More Authors

View Publication
Crossref
Publication Date
Sun Jun 05 2016
Journal Name
Baghdad Science Journal
Synthesis and Characterization of Cu(I)-Folic Acid Complex A Theoretical and Experimental Study
...Show More Authors

Copper (I) complex containing folic acid ligand was prepared and characterized on the basis of metal analyses, UV-VIS, FTIR spectroscopies and magnetic susceptibility. The density functional theory (DFT) as molecular modeling calculations was used to determine the donor atoms of folic acid ligand which appear clearly at oxygen atoms binding to hydrogen. Detection of donation sights is supported by theoretical parameters such as geometry, mulliken population, mulliken charge and HOMO-LUMO gap obtained by DFT calculations.

View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Wed Sep 14 2016
Journal Name
Journal Of Baghdad College Of Dentistry
Tooth Wear in Relation to Selected Salivary Variables among a Group of Older Adults
...Show More Authors

Background: Tooth wear is one of the most concerning problems of the current dental practice especially among older subjects. The aim of this study is to determine the severity of tooth wear and its relation with selected salivary variables (salivary pH and vitamin C level) among a group of older adults in Mosul city/Iraq. Materials and methods: All subjects (30 subjects) of both gender tookpart in the current study; sixteen of them were older adults (55-65 years) and compared with fourteen middle-aged adults (30-40 years) at Textile factory in Mosul city/Iraq. Unstimulated salivary samples were collected and salivary pH was immediately measured. Salivary vitamin C level was determined colormetrically. Severity of tooth wear was determined

... Show More
View Publication Preview PDF
Crossref