Tribology is the science and technology of interacting solid surfaces in relative motion, and its topics include the study of lubricants, lubrication, friction, wear, and bearings. It is estimated that friction and wear cost the US economy 6% of the gross national product [1]. For example, 5% of the total energy generated in an automobile engine is lost to frictional resistance. Also notable ar...

A small base isolation system using a new device that used friction force was developed. In this paper, dynamic characteristics of the system were investigated by an experiment using artificial seismic wave. The bearing combination of three cases, four spherical metal bearings, two spherical metal and two marble plate bearings, four marble plate bearings, was done in the experiment. The peak ac...

Bearing is a component that affects the performance of a rotating machine in order to be used properly. The purpose of using ball bearing is to reduce rotational friction and support radial and axial loads. Diagnosis of bearing vibration data is an important process to identify either the bearing is normal or defect. In this paper, we consider a single bearing system that consists of one normal...

Complex motions and wide variations in relative surface velocities are likely to be experienced in mechanical systems such as an engine (e.g., piston rings, wrist pins and crankshaft main bearings in a piston type engine). Currently available tribometers use simple motions and often a constant speed. A new tribometer is designed with the capability of three types of motions: (1) unidirectional ...

In the paper, a low friction pneumatic cylinder and a sliding table, and both of them are embedded with aerostatic bearings are designed. A low friction pneumatic table is constructed by combining the pneumatic cylinder and the sliding table. The characteristics for the friction force versus velocity of the pneumatic cylinder and the pneumatic table are measured. Moreover, a hybrid self-tuning ...

A very low coefficient of friction in joints makes it difficult to define clearly the mechanism of cartilage lubrication. The present paper describes the two currently predominant and mutually complementary views aiming to elucidate this mechanism. The first mechanism, referred to as hydrostatic lubrication, involves interstitial fluid pressurization from the cartilage and its importance for th...

Friction stir welding (FSW) is a widely used solid state joining process for soft materials such as aluminium alloys because it avoids many of the common problems of fusion welding. Commercial feasibility of the FSW process for harder alloys such as steels and titanium alloys awaits the development of cost effective and durable tools which lead to structurally sound welds consistently. Material...

Variable stiffness structures that enable a wide range of efficient load-bearing and dexterous activity are ubiquitous in mammalian musculoskeletal systems but are rare in engineered systems because of their complexity, power, and cost. We present a new negative stiffness-based load-bearing structure with dynamically tunable stiffness. Negative stiffness, traditionally used to achieve novel res...

This paper analyses the problem of modelling joint friction in robotic manipulators with gear transmissions at joint velocities varying from close to zero until their maximum appearing values. It is shown that commonly used friction models that incorporate Coulomb, (linear) viscous and Stribeck components are inadequate to describe the friction behaviour for the full velocity range. A new frict...

nitro-containing heteroaromatic derivatives structurally related to nitroimidazole (metronidazole) are being extensively evaluated against helicobacter pylori isolates. on the other hand, 1,3,4-thiadiazole derivatives have also demonstrated promising antibacterial potential. in present study, we evaluated anti-h. pylori activity of novel hybrid molecules bearing nitroaryl and 1,3,4-thiadiazole ...