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Effect of Bearing Compliance on Thermo-hydrodynamic Lubrication of High Speed Misaligned Journal Bearing Lubricated with Bubbly Oil
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Abstract

In the present work  the effect of bearing compliance on the performance of high speed misaligned journal bearing lined with a compliant PTFE liner lubricated with bubbly oil at high speeds has been studied. The effect of induced oil film temperature due to shearing effect has been implemented. Hydrodynamic effect of the complaint bearing and the influence of aerated oil have been examined by the classical thermohydrodynamic lubrication theory modified to include the effect of oil film turbulence and oil film temperature with suitable models for bubbly oil viscosity and density. The effect of liner elastic deformation has been implemented by using Winkler model. The effects of variable density and specific heat on the most importantbearing parameters such as maximum pressure, maximum temperature, bearing load carrying capacity and power losses have been investigated.The results obtained show that the oil film pressure and load carrying capacity increased for the bearing lubricated with bubbly oil of higher aeration level and smaller size of air bubbles. Including the effect of elastic deformation of the bearing liner reduces the oil film pressure, load carrying capacity and frictional power loss for the misaligned bearing working at the same circumstances

Keywords: Journal bearings, hydrodynamic lubrication, THD, compliant effect, bubbly oil, misalignment effect.

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Publication Date
Sat Mar 01 2008
Journal Name
Iraqi Journal Of Physics
Effect of Pressure on the Properties of HgBa2Ca2Cu3O8+δ HTSC System
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High temperature superconductors with a nominal composition HgBa2Ca2Cu3O8+δ
for different values of pressure (0.2,0.3, 0.5, 0.6, 0.9, 1.0 & 1.1)GPa were prepared by
a solid state reaction method. It has been found that the samples were semiconductor
P=0.2GPa.while the behavior of the other samples are superconductor in the rang
(80-300) K. Also the transition temperature Tc=143K is the maximum at P is equal to
0.5GPa. X-ray diffraction showed a tetragonal structure with the decreasing of the
lattice constant c with the increasing of the pressure. Also we found an increasing of
the density with the pressure.

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Publication Date
Tue Jan 01 2019
Journal Name
Indian Journal Of Public Health Research & Development
Effect of Orthodontic Force on Salivary Levels of Lactate Dehydrogenase Enzyme
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Orthodontic tooth movement is characterized by tissue reactions, which consist of an inflammatory response in periodontal ligament and followed by bone remodeling in the periodontium depending on the forces applied. These processes trigger the secretion of various proteins and enzymes into the saliva. The purpose of this study was to evaluate the activity of the lactate dehydrogenase (LDH) in saliva during orthodontic tooth movement using different magnitude of continuous orthodontic forces. Thirty orthodontic patients (12 males and 18 females) with ages 17-23 years with class II division I malocclusion all requiring bilateral maxillary first premolar extractions. Those patients were randomly divided into 3 groups according to the magnitude

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Publication Date
Mon Jun 01 2015
Journal Name
Int. J. Adv. Appl. Math. Andmech.
The effect of external source of disease on the epidemic model
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Publication Date
Mon Jan 01 2018
Journal Name
Ournal Of Advanced Research In Dynamical And Control System
Effect of magnetic field on peristaltic transport of bingham plastic fluid
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Publication Date
Sun Dec 06 2009
Journal Name
Baghdad Science Journal
Effect of salinity on survival, development and growth of Artemia sp.
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This study aimed to determine the possibility of culturing genus Artemia in under laboratory conditions for locally culturing and producing. Different salinity concentrations were used, ranging from 5-40g/l . the results showed that the concentration 30g/l is the best for hatching. This concentration recorded hatching efficiency of 68800 nauplii/g cysts and hatching percentage of 45.86%, while the concentration 5g/l recorded less hatching efficiency and hatching percentage of 20266 nauplii/g and 13.5% respectively . Investigating the effect of salinity on individuals survival and growth using saline concentrations ranging from 30to 100g/l, revealed that the best percentage was 75.00% in the first week with 70g/l, whilst the best rates of

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Publication Date
Sun Sep 01 2019
Journal Name
Civil Engineering Journal
Effect of PolyPhosphoric Acid on Rutting Resistance of Asphalt Concrete Mixture
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The action of high repeated trucks load associated with dramatically elevated ambient temperatures leads to the most harmful distress in asphalt pavements occurred in Iraq known as rutting. Essentially, it is produced from the accumulation of irrecoverable strains, which mainly occurred in the asphalt layers. That visually demonstrated as a longitudinal depression in the wheel paths as well as small upheavals to the sides. Poly Phosphoric Acid (PPA) has been used as a means of producing modified asphalt binders and the interest to use it has increased in recent years. The PPA provides modified asphalt binder, which is relatively cheaply produced compared to polymer-modified asphalt. In this paper, PPA was used by three-percentages 1

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Publication Date
Sun Jun 12 2011
Journal Name
Baghdad Science Journal
Effect of additive polyvinyl alcohol polymer on properties of cement – Silica
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Study the effect of additives polymer polyvinyl alcohol (PVA) after solving in water by concentration 10% since represent a standard of PVA solution with added to cement – silica composite of ratio (1:2) with 5%, 10%, 15%, 20%, and 25% respectively to the standard quantity of water which using as a mortar of building. The results are demonstrate increasing on compression resistance with increase of PVA solution until 20%, and decreasing of thermal conductivity which represent a composite are increasing in thermal insulating. The results were recommended decreasing of water absorption with increase of PVA solution ratio as illustrated in this study.

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Publication Date
Sun Apr 30 2017
Journal Name
Journal Of Engineering
Effect of Construction Joints on the Behavior of Reinforced Concrete Beams
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In this study, the effect of construction joints on the performance of reinforced concrete beams was experimentally investigated. Seven beam specimens, with dimensions of 200×100×1000 mm, were fabricated. The variables were considered including; the location and configuration of the joints. One beam was cast without a joint (Reference specimen), two specimens were fabricated with a one horizontal joint located either at tension, or compression zone. The fourth
beam had two horizontal joints placed at tension, and compression area. The remaining specimens were with one or two inclined joints positioned at the shear span or beam’s mid-span. The specimens were subjected to a monotonic central concentrated loading until the failure. T

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Publication Date
Tue Oct 02 2018
Journal Name
Iraqi Journal Of Physics
Effect of chelating agents on removal of 137Cs from contaminated soil
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In the present research, the chemical washing method has been selected using three chelating agents: citric acid, acetic acid and Ethylene Diamine Tetraacetic Acid (EDTA) to remove 137Cs from two different contaminated soil samples were classified as fine and coarse grained. The factors that affecting removal efficiency such as type of soil, mixing ratio and molarity have been investigated. The results revealed that no correlation relation was found between removal efficiency and the studied factors. The results also showed that conventional chemical washing method was not effective in removing 137Cs and that there are further studies still need to achieve this objective.

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Publication Date
Sun Sep 01 2024
Journal Name
Gazi University Journal Of Science
Effect of Natural Bitumen on the Performance of Hot Asphalt Mixture‏
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For over a century, the global consumption of asphalt binder in asphalt mixture production has been substantial. In the Heet region (west of Iraq), two distinct forms of natural asphalt (NA) deposits exist: rock asphalt and sulfur spring asphalt. This study focused on using NA sourced from sulfur springs. The aim was to investigate the potential of incorporating NA into local asphalt mixtures. To achieve this, NA was heated to 163°C for varying durations. After heat treatment, laboratory tests were conducted on NA. The findings suggest that by heating NA for 20 hours, it conforms to Iraqi specifications in terms of physical properties. Furthermore, compared to conventional petroleum asphalt, treated NA showed greater

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