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The influence of shifting the class I cavity position prepared in posterior teeth buccally and lingualy on stress distribution (Finite element analysis study)
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Background: Rehabilitation of the carious tooth to establish tooth structure integrity required cavity design that show a benign stress distribution. The aim of this study was to investigate the influence of the cavity position on the stress values in the reamining tooth structure restored with amalgam or resin composite. Materials and methods: Seven 2-D models of maxillary first premolar include class I cavity design was prepared, one sound tooth (A) 3 composite (B1, B2, and B3) and 3 amalgam (C1, C2, and C3). In design (BI and C1) the cavity position is in the mid distance between bacc-lingual cusp tip, design (B2 and C2) and (B3 and C3) shifted toward the buccal cusp and the lingual cusp for 0.5 mm respectively. One hundred N vertical load was applied and stress analysis was applied using Ansys v14 software. Results: The maximum Von Mises stress 585.35 MPa in the sound tooth and (899,46, 690.46, and 941.47) in central, buccal, and lingual cavities position filled with a composite restoration respectively. Whereas, the highest stress (1540.37 MPa), (1233.09 MPa) and (1214.34 MPa) appears with a central, buccal and lingual cavities filled with amalgam respectively. Conclusion: Reestablishment of the stress level of maxillary premolars subjected to class I cavity preparations are cavity bacc-lingual position and restorative-system-dependent. Key words: Cavity position, class I, amalgam, composite, stress level.

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Publication Date
Sun Mar 01 2020
Journal Name
Fisheries & Aquatic Life
Directional fluctuating asymmetry in certain morphological characters as a pollution indicator: Tigris catfish (<i>Silurus triostegus</i>) collected from the Euphrates, Tigris, and Shatt al-Arab Rivers in Iraq
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Abstract<p>The relationship between pollution levels in river sediment and fluctuating asymmetry of resident silurid fish species, <italic>Silurus triostegus</italic> Heckel, was assessed. Eight bilateral body proportions were analyzed in 1,500 fish from eight river locations. Sediment pollution was measured based on the analysis of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) and organochlorine pesticides (DDT, DDD, DDE, chlordane, dieldrin, and lindane). The mean quotient approach (mERMq) was used to characterize sediment toxicity, which ranged from low to moderate levels for heavy metals and from low to severe for organochlorides. Variation was noted in the measurements of fish body mor</p> ... Show More
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Publication Date
Thu Apr 03 2025
Journal Name
Engineering, Technology &amp; Applied Science Research
Application of the One-Step Second-Derivative Method for Solving the Transient Distribution in Markov Chain
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Markov chains are an application of stochastic models in operation research, helping the analysis and optimization of processes with random events and transitions. The method that will be deployed to obtain the transient solution to a Markov chain problem is an important part of this process. The present paper introduces a novel Ordinary Differential Equation (ODE) approach to solve the Markov chain problem. The probability distribution of a continuous-time Markov chain with an infinitesimal generator at a given time is considered, which is a resulting solution of the Chapman-Kolmogorov differential equation. This study presents a one-step second-derivative method with better accuracy in solving the first-order Initial Value Problem

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Publication Date
Thu Nov 30 2023
Journal Name
Iraqi Geological Journal
A Review on Pressure Transient Analysis in Multilayer Reservoir: South Iraq Case Study
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Multilayer reservoirs are currently modeled as a single zone system by averaging the reservoir parameters associated with each reservoir zone. However, this type of modeling is rarely accurate because a single zone system does not account for the fact that each zone's pressure decreases independently. Pressure drop for each zone has an effect on the total output and would result in inter-flow and the premature depletion of one of the zones. Understanding reservoir performance requires a precise estimation of each layer's permeability and skin factor. The Multilayer Transient Analysis is a well-testing technique designed to determine formation properties in more than one layer, and its effectiveness over the past two decades has been

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Publication Date
Mon Oct 12 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation of fracture strength of endodontically treated teeth restored by milled zirconia post and core with different post and core systems (An in vitro comparative study)
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Background: Restoration of root canal treated teeth with a permanent restoration affect in the success of endodontically treated teeth. This in vitro study was performed to evaluate and compare the fracture strength of endodontically treated teeth restored by using custom made zirconium posts and cores, prefabricated carbon fiber, glass fiber and zirconium ceramic posts. Materials and method: Forty intact human mandibular second premolars were collected for this study and were divided into five groups. Each group contains 8 specimens: Group1: Teeth restored with Carbon Fiber Posts; Group2: Teeth restored with Glass Fiber Posts; Group3: Teeth restored with Zirconium Ceramic prefabricated Posts; Group4: Teeth restored with Zirconium Posts

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Publication Date
Mon Oct 12 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation of tissue displacement in posterior palatal seal area with different impression techniques with varying palatal forms
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Background: This study was designed to measure the displacement pattern of posterior palatal seal (pps) area in different forms of the palate and with different impression techniques. Materials and method: This study was used to measure the displacement pattern of (pps)in different palatal shapes by using different impression materials Korrecta wax No.4,Green compound and design of House for pps for each palatal forms by using a 3D Scanner of CAD/CAM and measuring the distance between 2 points in pps area by using Caural Threw. Result: The results show highly significant differences between these techniques and the control group (impression with light body) Conclusion: The physiological impression technique of pps with Korecta wax no.4

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Publication Date
Mon Mar 01 2010
Journal Name
Journal Of Economics And Administrative Sciences
Estimating the general exponential distribution parameters using the simulation method
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The main aim of this paper is to study how the different estimators of the two unknown parameters (shape and scale parameter) of a generalized exponential distribution behave for different sample sizes and for different parameter values. In particular, 

. Maximum Likelihood, Percentile and Ordinary Least Square estimators had been implemented for different sample sizes (small, medium, and large) and assumed several contrasts initial values for the two parameters. Two indicators of performance Mean Square Error and Mean Percentile Error were used and the comparisons were carried out between different methods of estimation  by using monte carlo simulation technique .. It was obse

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Publication Date
Wed Jan 01 2014
Journal Name
Journal Of The College Of Languages (jcl)
The Influence of Manipulating the Virtual Library in Comparison with the Individual Learning via Computer Use in English Language
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The study aims at investigating the effectiveness of the Virtual Library Technology, in developing the achievement of the English Language Skills in the Center of Development and Continuous Education, in comparison with the individual learning via personal computer to investigate the students' attitude towards the use of both approaches. The population of the study includes the participants in the English Language course arranged in the Center. The sample includes 60 students who were randomly chosen from the whole population (participants in English Courses for the year 2009-2010). The sample is randomly chosen and divided into two experimental groups. The first group has learned through classroom technology; while the other group has l

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Publication Date
Sat May 01 2021
Journal Name
Turkish Journal Of Computer And Mathematics Education
Analysis of The Chemistry Book for The Third Grade Medium on The Skills of The 21st Century
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The current study aims to analyze the content of the chemistry book for the third middle grade according to the skills of the 21st century for the academic year (2020-2021). To achieve this goal, a list of 21st century skills to be included in the chemistry book for the third grade was built after a series of literature, research and previous studies, as the 21st century skills tool was built with its main and sub-skills in its initial form consisted of (68) indicators distributed in three main groups and presented the list to a group of specialists in the field of curriculum and teaching methods, Thus the tool was formed in its final form of (59) subissue, and then analyzed the content of the chemistry book for the third grade intermediate

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Publication Date
Wed Jun 29 2022
Journal Name
Journal Of The College Of Education For Women
The Chicago School in Urban Sociology: A Socio-Historical Approach on the Pragmatic Thought Influence as a Theoretical Frame of Reference in it-1892-2020
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The present theoretical study analyzes the legacy of the Chicago School of Urban Sociology and evaluates it in the light of the growth and development of Chicago City and the establishment of sociology in it. Sociology has become an academic discipline recognized in the United States of America in the late nineteenth century, particularly, after the establishment of the first department of sociology in the University of Chicago in 1892. That was during the period of the rapid industrialization and sustainable growth of the Chicago City. The Chicago School relied on Chicago City in particular, as one of the American cities that grew and expanded rapidly in the first two decades of the twentieth century. At the end of the nineteenth centur

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Publication Date
Fri Jan 01 2016
Journal Name
Journal Of Engineering
Mobile position estimation using artificial neural network in CDMA cellular systems
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Using the Neural network as a type of associative memory will be introduced in this paper through the problem of mobile position estimation where mobile estimate its location depending on the signal strength reach to it from several around base stations where the neural network can be implemented inside the mobile. Traditional methods of time of arrival (TOA) and received signal strength (RSS) are used and compared with two analytical methods, optimal positioning method and average positioning method. The data that are used for training are ideal since they can be obtained based on geometry of CDMA cell topology. The test of the two methods TOA and RSS take many cases through a nonlinear path that MS can move through that region. The result

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