DEVELOPMENT OF A METHODOLOGY FOR SMALL SCALE CASING WEAR TESTING

2019 ◽  
Author(s):  
Edja Iandeyara Freitas Moura ◽  
Juliano Oséias de Moraes ◽  
João Pedro Costa Cardoso ◽  
Joseir Percy ◽  
Sinésio Franco
Keyword(s):  
Wear Testing ◽  
Small Scale ◽  
Casing Wear

The Frictional Stability of Wet Clutch Friction Materials Investigated on a Small Scale Test-Rig

2005 ◽  
Author(s):  
W. Ost ◽  
P. De Baets
Keyword(s):  
Relative Velocity ◽  
Normal Load ◽  
Wear Testing ◽  
Small Scale ◽  
Mechanical Parameters ◽  
Test Rig ◽  
Friction Materials ◽  
Wet Clutch ◽  
Friction Clutch ◽  
Scale Test

The work presented in this paper is part of a European project (COST 532, project E2) to study clutch shudder and its influences, together with wear testing of clutch materials. The relation between the friction force and the relative velocity, and the dynamics thereof are investigated for typical wet clutch materials (oil lubricated paper/steel contact) on a small scale test rig, using a ground and polished steel ring onto which a coupon from a friction clutch plate was slid. The results clearly show that although momentarily the relative velocity of the sliders vs. the rotating ring reaches zero, no stick episode ensues. The mechanical parameters (stiffness, damping and normal load) of the test-rig were varied and the influence thereupon on the friction during sliding was investigated.

An Investigation of the Thermal Sprayed Molybdenum Coatings Behaviour to Micro-Abrasion Wear

2016 ◽  
Vol 841 ◽  
pp. 15-20
Author(s):  
Gheorghe Matache ◽  
Alexandru Paraschiv ◽  
Cristian Puscasu
Keyword(s):  
Experimental Data ◽  
Wear Rate ◽  
Electric Arc ◽  
Wear Testing ◽  
Wear Behaviour ◽  
Small Scale ◽  
Wear Rates ◽  
Wear Mode ◽  
Three Body Abrasion ◽  
Three Body

The wear behaviour of thick molybdenum coatings deposited by electric arc thermal spray on steel support was investigated by micro-abrasion, a relatively recent introduced method for small scale wear testing. The wear mechanisms and wear rates without coatings penetration were investigated with respect of time corresponding to primary and secondary wear stages. The micro-abrasion of Mo coatings using SiC abrasive slurry have been discussed and wear scar characteristics were evaluated based on the experimentally results. The worn surfaces of the tested specimen were examined by SEM and the specific wear rate was calculated from experimental data. For the testing durations used it was identified the change from grooving to rolling wear corresponding to the transition of wear mode from two-body to three body-abrasion.

Evaluation of Worn Tubulars from DEA-42 and Small-Scale Casing Wear Testers

2011 ◽  
Author(s):  
Abbe E.R. Doering ◽  
Daniel Robert Danks ◽  
Salah E. Mahmoud ◽  
Joe Lynn Scott
Keyword(s):  
Small Scale ◽  
Casing Wear

Reasons to strike first

2019 ◽  
Vol 42 ◽  
Author(s):  
William Buckner ◽  
Luke Glowacki
Keyword(s):  
Intergroup Conflict ◽  
Small Scale

Abstract De Dreu and Gross predict that attackers will have more difficulty winning conflicts than defenders. As their analysis is presumed to capture the dynamics of decentralized conflict, we consider how their framework compares with ethnographic evidence from small-scale societies, as well as chimpanzee patterns of intergroup conflict. In these contexts, attackers have significantly more success in conflict than predicted by De Dreu and Gross's model. We discuss the possible reasons for this disparity.

Exploring Coronal Structures with SOHO

2000 ◽  
Vol 179 ◽  
pp. 403-406
Author(s):  
M. Karovska ◽  
B. Wood ◽  
J. Chen ◽  
J. Cook ◽  
R. Howard
Keyword(s):  
Solar Corona ◽  
Image Enhancement ◽  
Coronal Mass Ejections ◽  
Dynamical Evolution ◽  
Small Scale ◽  
Low Contrast ◽  
Contrast Structures ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Coronal Structures

AbstractWe applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.

Scanning tunneling microscopy and atomic force microscopy: New tools for biology

1989 ◽  
Vol 47 ◽  
pp. 778-779
Author(s):  
CE Bracker ◽  
P. K. Hansma
Keyword(s):  
Physical Property ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Small Scale ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
New Family ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.

TEM sample preparation of wear-tested room-temperature pulsed-laser-deposited thin films of MoS2 by ultramicrotomy

1993 ◽  
Vol 51 ◽  
pp. 1118-1119
Author(s):  
Pamela F. Lloyd ◽  
Scott D. Walck
Keyword(s):  
Thin Films ◽  
Sample Preparation ◽  
Room Temperature ◽  
High Vacuum ◽  
Pulsed Laser ◽  
Ultra High Vacuum ◽  
Wear Testing ◽  
Preparation Technique ◽  
Cross Sectional ◽  
Aerospace Applications

Pulsed laser deposition (PLD) is a novel technique for the deposition of tribological thin films. MoS2 is the archetypical solid lubricant material for aerospace applications. It provides a low coefficient of friction from cryogenic temperatures to about 350°C and can be used in ultra high vacuum environments. The TEM is ideally suited for studying the microstructural and tribo-chemical changes that occur during wear. The normal cross sectional TEM sample preparation method does not work well because the material’s lubricity causes the sandwich to separate. Walck et al. deposited MoS2 through a mesh mask which gave suitable results for as-deposited films, but the discontinuous nature of the film is unsuitable for wear-testing. To investigate wear-tested, room temperature (RT) PLD MoS2 films, the sample preparation technique of Heuer and Howitt was adapted.Two 300 run thick films were deposited on single crystal NaCl substrates. One was wear-tested on a ball-on-disk tribometer using a 30 gm load at 150 rpm for one minute, and subsequently coated with a heavy layer of evaporated gold.

Superstructures and ordering phenomena in ceramic superconductors

1996 ◽  
Vol 54 ◽  
pp. 710-711
Author(s):  
R. Gronsky
Keyword(s):  
Domain Growth ◽  
Small Displacement ◽  
Small Scale ◽  
Ceramic Superconductors ◽  
Oxygen Sublattices ◽  
Tweed Contrast ◽  
Diffraction Patterns ◽  
Representative Image ◽  
Static Lattice ◽  
Modulation Wavelength

It is now well established that the phase transformation behavior of YBa2Cu3O6+δ is significantly influenced by matrix strain effects, as evidenced by the formation of accommodation twins, the occurrence of diffuse scattering in diffraction patterns, the appearance of tweed contrast in electron micrographs, and the generation of displacive modulation superstructures, all of which have been successfully modeled via simple Monte Carlo simulations. The model is based upon a static lattice formulation with two types of excitations, one of which is a change in oxygen occupancy, and the other a small displacement of both the copper and oxygen sublattices. Results of these simulations show that a displacive superstructure forms very rapidly in a morphology of finely textured domains, followed by domain growth and a more sharply defined modulation wavelength, ultimately evolving into a strong <110> tweed with 5 nm to 7 nm period. What is new about these findings is the revelation that both the small-scale deformation superstructures and coarser tweed morphologies can result from displacive modulations in ordered YBa2Cu3O6+δ and need not be restricted to domain coarsening of the disordered phase. Figures 1 and 2 show a representative image and diffraction pattern for fully-ordered (δ = 1) YBa2Cu3O6+δ associated with a long-period <110> modulation.

Indirect Assessment of Attitudes with Response-Time-Based Measures

2006 ◽  
Vol 37 (3) ◽  
pp. 131-139 ◽  
Author(s):  
Juliane Degner ◽  
Dirk Wentura ◽  
Klaus Rothermund
Keyword(s):  
Social Cognitive ◽  
Incremental Validity ◽  
Self Report ◽  
Small Scale ◽  
Implicit Measures ◽  
Scale Theory ◽  
Starting Point ◽  
Self Reports ◽  
Predicting Behavior ◽  
Social Cognitive Theories

Abstract: We review research on response-latency based (“implicit”) measures of attitudes by examining what hopes and intentions researchers have associated with their usage. We identified the hopes of (1) gaining better measures of interindividual differences in attitudes as compared to self-report measures (quality hope); (2) better predicting behavior, or predicting other behaviors, as compared to self-reports (incremental validity hope); (3) linking social-cognitive theories more adequately to empirical research (theory-link hope). We argue that the third hope should be the starting point for using these measures. Any attempt to improve these measures should include the search for a small-scale theory that adequately explains the basic effects found with such a measure. To date, small-scale theories for different measures are not equally well developed.

Small-Scale Science to Large-Scale Profession

2000 ◽  
Vol 45 (4) ◽  
pp. 396-398
Author(s):  
Roger Smith
Keyword(s):  
Large Scale ◽  
Small Scale
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