Performance Characteristics of Lubricating Oil Film Between Rotating Disks

1960 ◽  
Vol 82 (1) ◽  
pp. 19-28 ◽  
Author(s):  
S. I. El-Sisi ◽  
G. S. A. Shawki
Keyword(s):  
Testing Machine ◽  
Lubricating Oil ◽  
Test Results ◽  
Rotating Disks ◽  
Rolling Velocity ◽  
Oil Film ◽  
Gear Teeth ◽  
Pure Rolling ◽  
Theoretical Investigations ◽  
The Subject

A testing machine has been designed to investigate the performance of the lubricating oil film between two independently driven circular disks in line contact under conditions of combined rolling and sliding, in an endeavor to study the behavior of meshing gear teeth with adequate supply of lubricant. Test results show that the ratio of sliding to rolling velocity is a prime factor in the behavior of rotating disks. Values of this ratio equal to zero and unity (conditions of pure rolling and pure sliding, respectively) give rise to critical changes in the performance of the disks, being most favorable, from a lubrication viewpoint, at pure rolling (i.e., at the gear pitch line) and least favorable at pure sliding where scuffing of surfaces may well be expected Recent theoretical investigations do not seem to be able yet to account for salient results obtained in the present study. Further work on the subject is proceeding.

Measurement of Oil-Film Thickness Between Disks by Electrical Conductivity

1960 ◽  
Vol 82 (1) ◽  
pp. 12-16 ◽  
Author(s):  
S. I. El-Sisi ◽  
G. S. A. Shawki
Keyword(s):  
Electrical Conductivity ◽  
Film Thickness ◽  
Testing Machine ◽  
Rotating Disk ◽  
Substantial Improvement ◽  
Film Resistance ◽  
Test Results ◽  
Oil Film ◽  
Gear Teeth ◽  
Special Apparatus

A special apparatus is designed to measure the oil-film thickness between two stationary disks (simulating meshing gear teeth) by applying a-c or d-c potential across the film and measuring its resistance for given gap between the disks. Experiments show that the treatment of oil with additive (sodium-petroleum sulphonate in this case) may well lead to a considerable increase in its electrical conductivity, and to a substantial improvement in the independence of the oil-film resistance of the electrical history and temperature of the oil. A reliable relationship could eventually be obtained between the oil-film resistance and relevant thickness. Test results are employed in investigating the behavior of the oil film in a rotating-disk testing machine developed by the authors for studying the performance of meshing gear teeth with adequate supply of lubricant.

IMPROVE THE INTERETATION OF STUDY SUBJECTS PANCASILA AND CITIZENSHIP EDUCATION BY APPLYING KONSTEXTUAL LEARNING MODEL BERBASIS A TASK IN CLASS INFORMATICS XI SMK BINA ECLECTUS ACADEMIC YEAR 2015/2016

EDUKASI ◽  
2016 ◽  
Vol 13 (2) ◽  
Author(s):  
Hasanudin S. Usman
Keyword(s):  
Teaching And Learning ◽  
Learning Model ◽  
Positive Influence ◽  
Motivation To Learn ◽  
Test Results ◽  
Applied Learning ◽  
Know How ◽  
Design Activities ◽  
The Subject ◽  
Academic Year

The purpose of this research is to know how to incerease the students’ learning achievement that has been applied learning contextual task-based learning model and to know the influence of contextual learning in  the task-based teaching model to improve achievemen and motivation to learn the material pe civis lesson.   This research is an action research by theree rounds. Each round consists of four phases. Design activities are observation, and revesion. The subject of the research is XI grade students of Bina Informatika Ternate accademic year 2015/2016. Data obtained in the form of a formative test results, observation sheet teaching and learning activities. The results of the research showed that students’ achivement increased from round I to III that the round 1, (70.00 % ), (92,50 %)  3 cycles, conclusions of this research is the method of cooperatif learning can be a positive influence on students motivation and achievement in material udaya politics in Indonesia. It means that this model can be used as one of the alternative learning for Pkn.            Kata  kunci: PKn, cooperative learning method

Methodology to Increase Flexibility in Inter-Region Flow Control for Urban Traffic

2021 ◽  
pp. 036119812199742
Author(s):  
Sunghoon Kim ◽  
Monica Menendez ◽  
Hwasoo Yeo
Keyword(s):  
Flow Control ◽  
Real Time ◽  
Urban Traffic ◽  
Test Results ◽  
Flow Restriction ◽  
Region Flow ◽  
The Subject ◽  
Negative Impacts ◽  
Transfer Flow ◽  
Supply Level

Perimeter control is used to regulate transfer flows between urban regions. The greedy control (GC) method takes either the minimum or the maximum for the control inputs. Although it has the advantage of simplicity for real-time feasibility, a few existing studies have shown that it can sometimes have negative impacts because of unnecessary transfer flow restrictions. To reduce unnecessary restrictions, this study provides a method that gives flexibility to ease the strict conditions of the conventional GC. First, we propose a modification as a way of granting exceptions to the flow restriction under specific conditions. Second, we develop an algorithm to determine the threshold dynamically for accepting the exception, by comparing the possible outflow loss of the subject region and the possible outflow gain of its neighboring regions. The test results show that this flexible greedy control can handle the balance between the transfer demands and the greed of regions for securing the supply level, while increasing the performance in both vehicle hours traveled and trip completion.

Creep Tests of Rotating Disks at Elevated Temperature and Comparison With Theory

1954 ◽  
Vol 21 (3) ◽  
pp. 225-235
Author(s):  
A. M. Wahl ◽  
G. O. Sankey ◽  
M. J. Manjoine ◽  
E. Shoemaker
Keyword(s):  
Elevated Temperatures ◽  
Experimental Program ◽  
Test Results ◽  
Rotating Disks ◽  
Creep Tests ◽  
Shear Theory ◽  
Heat Treated ◽  
Long Time ◽  
Average Tension ◽  
Creep Deformations

Abstract A theoretical and experimental program involving methods of calculating creep in rotating disks at elevated temperatures is described. This program consisted primarily of the following: (a) Obtaining forged disks from the same ingot of 12 per cent chrome steel, all disks being forged and heat-treated in the same manner; (b) making spin tests at 1000 F on three of these disks for periods up to about 1000 hr; ( ) making long-time tension-creep tests at 1000 F on many specimens cut out circumferentially from several of the other disks at stresses approximating those of the spin tests; (d) investigating theoretical methods of calculation of creep deformation in such disks; and (e) comparison of spin-test results with those calculated theoretically using average tension-creep data. It was found that available methods of calculating rotating disks based on the Mises criterion gave creep deformations too low compared to the test values, i.e., on the unsafe side for design. Considerably better agreement between test and theoretical results is obtained if the latter is based on the maximum-shear theory. Some discussion is given of the reasons for the better agreement obtained using the latter theory; these are believed to be related in part to the anisotropy of the forged material tested. Further tests on other materials are necessary before general conclusions can be drawn; however, in the absence of test data it is suggested that a conservative course in design for such disks is to apply the maximum-shear theory.

Experiments on Oil-Film Dampers for Turbomachinery

1976 ◽  
Vol 98 (3) ◽  
pp. 393-399 ◽  
Author(s):  
M. Botman
Keyword(s):  
Dynamic Responses ◽  
Maximum Speed ◽  
Test Results ◽  
Oil Film ◽  
Outer Race ◽  
High Speeds ◽  
Typical Test

Oil-film dampers are used in turbomachinery to suppress undesirable shaft dynamic responses. They are located at the nonrotating outer race of selected main bearings. A rig is described that was designed to evaluate the effect of damper geometry on the rotor responses. Typical test results are shown which indicate that cavitation limits the maximum speed at which dampers should be used. Below cavitation speed the effect of the damper appears predictable with existing theory. More tests are required to substantiate this. At high speeds the damper generates nonsynchronous motion. The damper may have a significant effect on the stiffness of the support felt by the rotor.

scholarly journals Are Australian Teachers Making the Grade? A Study of News Coverage of Naplan Testing

2015 ◽  
Vol 154 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Kathryn Shine
Keyword(s):  
News Media ◽  
News Coverage ◽  
Developed Countries ◽  
Testing System ◽  
Journalism Education ◽  
Test Results ◽  
National Assessment ◽  
The Subject ◽  
Standardised Testing ◽  
And Training

The standardised testing of school children has been the subject of significant news media attention in recent years in many developed countries around the world. This article examines the reporting of annual National Assessment Program Literacy and Numeracy (NAPLAN) tests in three major Australian newspapers, with a particular focus on the portrayal of school teachers in the coverage. Overall, teachers were presented as strongly opposed to NAPLAN and the publication of test results, yet the newspapers themselves supported the tests as an important accountability measure. Teachers were depicted as trying to influence the testing system through teaching to the test and cheating. They were presented as generally inadequate as teachers, and were blamed for perceived failings in the educational system. These findings point to implications for teacher recruitment and retention, and for journalism education and training.

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