Preferred Language
Articles
/
alkej-503
The Effect of Surface Roughness on Thermohydrodynamic Performance in Misaligned Journal Bearings
...Show More Authors

     In this work an approach has been developed to investigate the influence of surface roughness on thermohydrodynamic performance in aligned and misaligned journal bearings by considering an average flow model and deriving the shear flow factor for various roughness configurations, similar to the pressure flow factor. An average Reynolds equation for rough surfaces is defined in term of pressure and shear flow factors, which can be obtained by numerical flow simulation, though the use of measured or numerically generated rough surfaces. Reynolds, heat conduction and energy equations are solved simultaneously by using a suitable numerical technique (Finite Difference Method) to obtain the pressure and temperature distribution through the oil film thickness of the journal bearing. These equations are obtained for isotropic surfaces and for surfaces with directional patterns. The flow factors for these surfaces are expressed as empirical relations in term of normalized oil film thickness (h/σ) and surface characteristic (γ) defined as the ratio of x and z correlation lengths . The results of this approach showed increase in load carrying capacity and maximum pressure and decrease in maximum temperature in the case of stationary surface roughness (rough bearing and smooth journal) with transverse pattern. The results obtained through this work have been compared with that published by other works and found to be in a good agreement.  

View Publication Preview PDF
Quick Preview PDF
Publication Date
Sat Dec 31 2022
Journal Name
Journal Of Economics And Administrative Sciences
The Effect of Workplace Respect on Employee Performance: A Survey Study in Abu Ghraib Dairy Factory
...Show More Authors

This paper aims to explain the effect of workplace respect on employee performance at Abu Ghraib Dairy Factory (AGDF). For achieving the research aim, the analytical and descriptive approach was chosen using a questionnaire tool for collecting data.  It covers 22 items; ten of them for the workplace respect variable and twelve items for the employee performance variable. The research population involved human resources who work at AGDF in Baghdad within two administrative levels (top and middle). We conducted a purposive stratified sample approach. It was distributed 70 questionnaire forms, and 65 forms were received. However, six of them had missing data and did not include in the final data analysis. The main results are t

... Show More
View Publication Preview PDF
Publication Date
Fri Sep 15 2017
Journal Name
Journal Of Baghdad College Of Dentistry
The Effect of Artificial Saliva on The Surface Roughness of Different Esthetic Archwires (An in Vitro Study)
...Show More Authors

Background:The demand for esthetic orthodontic appliances is increasing so that the esthetic orthodontic archwires were introduced. This in vitro study was designed to evaluate the surface roughness offiber-reinforced polymer composite (FRPC) archwires compared to coated nickel-titanium (NiTi) archwires immersed in artificial saliva. Materials and Methods:Three types of esthetic orthodontic archwires were used: FRPC (Dentaurum), Teflon coated NiTi (Dentaurum) and epoxy coated NiTi (Orthotechnology). They were round (0.018 inch) in cross section and cut into pieces of 15 mm in length.Forty pieces from each type were divided into four groups; one group was left at a dry condition and the other three groups were immersed in artificial saliva (

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Thu Jan 04 2024
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The effect of intellectual capital on sustainable competitive performance: field research in a sample of private colleges
...Show More Authors

Abstract:

                  This research seeks to test the influence of intellectual capital as an explanatory variable and its components (human capital, structural capital, relational capital) and sustainable competitive performance as a responsive variable and its components (reducing service delivery cycle time, rapid response to market demand, increasing customer satisfaction, providing better Quality of service, increasing market share)” through a field study, and here the research problem was diagnosed in an attempt to answer the following question: Is there awareness among the senior management within the private colle

... Show More
View Publication Preview PDF
Publication Date
Tue Dec 24 2024
Journal Name
Journal Of Baghdad College Of Dentistry
The Effect of Remineralizing Toothpastes on Enamel Surface Roughness after Hybrid Laser Bleaching (An In vitro Study)
...Show More Authors

Background: one of the complications of power bleaching is surface roughness of enamel which increases the possibility of post bleaching teeth discoloration. The aim of the present study is to evaluate the effect of toothpaste containing nano hydroxyapatite, NovaMin and kin sense fluoride on surface roughness of human tooth enamel after laser bleaching with 35% hydrogen peroxide bleaching gel. Materials and Methods: Twenty human enamel incisors were cleaned and their labial surface polished up to #1200, then categorized into four equal groups; first group kept without bleaching as a control group, while the remaining three experimental groups were bleached with 35% hydrogen peroxide, and each group treated with a restore paste containing o

... Show More
View Publication Preview PDF
Publication Date
Sun Sep 01 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Measuring the Social Responsibility and its Impact on the Financial Performance of Banks: Applied Research in the Iraqi National Bank
...Show More Authors

The objective of the research is to measure the impact of social responsibility on the financial performance of the National Bank of Iraq for the period from 2014 to 2016 (3 years) through discussing and analyzing the level of practice of the Bank of Baghdad for social responsibility and the impact on their financial performance during the period. To measure the independent variable (CSR), the researcher used the CSR Disclosure Index and relied on the ROA as an indicator to measure the dependent variable (financial performance). The results of the research showed the main hypothesis of the research, which states that the social responsibility of the banks has no significant impact on the financial performance. In relation to the disclosu

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Thu Jan 07 2021
Journal Name
Indian Journal Of Forensic Medicine & Toxicology
Effect of Dentifrices with Different Abrasives on the Surface Roughness of a Nano Composite Resins materials
...Show More Authors

Background: to evaluate the effect of different dentifrices on the surface roughness of two composite resins (nanofilled-based and nanoceramic – based composite resins). Materials and methods: Forty specimens (diameter 12 mm and height of 2mm) prepared from different composite resin materials: Z350 (nanofilled composite, and Ceram-X (nanoceramic) .they were subjected to brushing simulation equivalent to the period of 1 year. The groups assessed were a control group brushed with distilled water (G1), Opalescence whitening toothpasteR (G2), Colgate sensitive pro-relief (G3) and Biomed Charcoal Toothpaste (G4). The initial and final roughness of each group was tested by surface roughness tester. The results were statistically analyzed using

... Show More
View Publication
Scopus Crossref
Publication Date
Tue Jun 01 2021
Journal Name
Baghdad Science Journal
Cobalt Effect on the Growth of Cadmium Oxide Nanostructure Prepared by Spray Pyrolysis Technique
...Show More Authors

Spray pyrolysis technique (SPT) is employed to synthesize cadmium oxide nanostructure with 3% and 5% Cobalt concentrations. Films are deposited on a glass substrate at 350 ᵒC with 150 nm thickness. The XRD analysis revealed a polycrystalline nature with cubic structure and (111) preferred orientation. Structural parameters represent lattice spacing, crystallite size, lattice parameter and dislocation density. Homogeneous surfaces and regular distribution of atoms were showed by atomic force microscope (AFM) with 1.03 nm average roughness and 1.22 nm root mean square roughness. Optical properties illustrated a high transmittance more than 85% in the range of visible spectrum and decreased with Co concentration increasing. The absorption

... Show More
View Publication Preview PDF
Scopus (14)
Crossref (11)
Scopus Clarivate Crossref
Publication Date
Tue Dec 24 2024
Journal Name
Journal Of Baghdad College Of Dentistry
The effect of glass flakes reinforcement on the surface hardness and surface roughness of heat-cured poly (methyl methacrylate) denture base material
...Show More Authors

Background: Heat-cured poly (methyl methacrylate) the principal material for the fabrication of denture base have a relatively poor mechanical properties. The aim of this study was to investigate the effect of glass flakes used as reinforcement on the surface hardness and surface roughness of the heat-processed acrylic resin material. Material and method: Glass flakes (product code: GF002) pretreated with silane coupling agent were added to Triplex® denture base powder using different concentrations. A total of 100 specimens of similar dimensions (65 x 10 x 2.5) mm were prepared, subdivided into 2 main groups of 50 specimens for each of the study tests. Ten specimens for the control group and 40 specimens for each of the experimental gro

... Show More
View Publication Preview PDF
Publication Date
Tue Mar 01 2016
Journal Name
Journal Of Engineering
Dynamic Stability Analysis and Critical Speed of Rotor supported by a Worn Fluid film Journal Bearings
...Show More Authors

In this paper, the effect of wear in the fluid film journal bearings on the dynamic stability of rotor bearing system has been studied depending on the development of new analytical equations for motion, instability threshold speed and steady state harmonic response for rotor with offset disc supported by worn journal bearings. Finite element method had been used for modeling the rotor bearing system. The analytical model is verified by comparing its results with that obtained numerically for a rotor supported on the short bearings. The analytical and numerical results showed good agreement with about 8.5% percentage error in the value of critical speed and about 3.5% percentage error in the value of harmonic response. T

... Show More
View Publication Preview PDF
Publication Date
Tue Dec 24 2024
Journal Name
Journal Of Baghdad College Of Dentistry
The effect of in office bleaching on surface roughness and micro-hardness of newly developed composite materials (In vitro study)
...Show More Authors

Background: Alterations in the microhardness and roughness are commonly used to analyze the possible negative effects of bleaching products on restorative materials. This in vitro study evaluated the effect of in-office bleaching (SDI pola office +) on the surface roughness and micro-hardness of four newly developed composite materials (Z350XT –nano-filled, Z250XT-nano-hybrid, Z250-mico-hybrid and Silorane-silorane based). Materials and methods: Eighty circular samples with A3 shading were prepared by using Teflon mold 2mm thickness and 10mm in diameter. 20 samples for each material, 10 samples for base line measurement (surface roughness by using portable profillometer, and micro-hardness by usingDigital Micro Vickers Hardness Test

... Show More
View Publication Preview PDF