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Gresham B.,STLE
Tribology and Lubrication Technology | Year: 2012

The article reviews the basic types of bearings, both plain and rolling element, and the role of lubrication in their functioning. A plain bearing, also known as a plane bearing or a friction bearing, is the simplest type of bearing, comprising just a bearing surface. Plain bearings are the least expensive type of bearing. They are also compact, lightweight and have a high load-carrying capacity. Lubrication is generally provided by grooving that supplies and distributes the grease or oil. When up to speed, the lubrication regime is hydrodynamic. The next major class of bearings is rolling element bearings, which the ball bearing is one of the most common. Ball bearings tend to have lower load capacity for their size than other kinds of rolling element bearings due to the smaller contact area between the balls and races. Source

Gresham R.M.,TLT | Gresham B.,STLE
Tribology and Lubrication Technology | Year: 2015

Dr. Brandon Krick from Lehigh University, with Dr. Greg Sawyer from the University of Florida, presented an article on the dentition of dinosaurs. The researchers found six different materials making up the hadrosaur?s teeth. By scratching the different tissues with a very fine diamond-tipped stylus and measuring the abrasion, Krick found that the different tissues had differing resistances to abrasion. Thus, as the tooth underwent wear, the softer parts wore preferentially. This resulted in the surrounding harder areas acting like six levels of a sharpened tool. In effect, the tooth surface was, over time, in a dynamic state of change resulting in constant resurfacing of the tooth as it wore. This process kept the surface of the tooth rough in texture with degrees of high hard places and some with hard sharp edges, all good for grinding. Source

Matsumoto K.,Honda Corporation | Sasaki A.,STLE | Yoshida N.,Kyushu University
Society of Tribologists and Lubrication Engineers Annual Meeting and Exhibition 2015 | Year: 2015

Recently it has been reported that bearing damages of gear boxes for wind power generators are often caused by wear and failure due to electric discharges. Electric discharges also occur in gear boxes for automobiles but do not end up in failure. Therefore, electric discharge simulation tests were carried on the surfaces of bearing balls that had been operated well for a long time. The test results showed that the brown film on the surface of used bearing balls was non-crystalline carbon film and that the film protected the surface metal structure from melting and damaging when electric discharge was caused. The voltage from sliding was estimated as roughly 0.05 kV, however, this suppression was observed at 1.5 kV, which far exceeded this estimation. Depositing this non-crystalline carbon film or similar diamond-like carbon (DLC) film on the sliding surface would protect the surface from damage by electric discharge. Source

Gresham R.M.,STLE
Tribology and Lubrication Technology | Year: 2013

The article focuses on the need of making maximum use of sun energy with the help of sustainable products created using innovative technologies. Sustainability really deals with resource management, and those resources ultimately come from the sun in the form of energy. Through innovation researchers must improve on the existing technologies, look for ways to reduce waste and recycle through green chemistry. Those first two goals, if researchers want to be sustainable, are fairly self-evident. There are often various synthetic pathways in organic chemistry, leading to a given final product. The new way of thinking is not just about how elegantly I make some material but, rather, which of the possible syntheses utilize a greener pathway, use greener reagents and solvents, involve greener intermediates and end-products and which syntheses are inherently safer and use more waste-free chemistry. Source

Gresham B.,STLE
Tribology and Lubrication Technology | Year: 2014

The article explains how a little bit of variation can lead to a lot of problems with the customers when it comes to meeting product specifications. This is where organizations like the American Society for Testing and Materials come in. Working with a cross-section of industry, ASTM develops standards for materials and test methods. Through calibration, bias generally can be reduced or eliminated. Precision has to do with the variability of the test method itself. Reproducibility addresses the difference between two single and independent results obtained by different operators working in different laboratories on identical test material in the normal and correct operation of the test method. The method's worked penetration variability for more than one lab and operator is 20 units. Clearly, in the design and specification of various systems, consideration of our ability to measure and verify the components that make up the system needs to be given priority at the very beginning. Source

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