Production of many synthetic lubricants starts with base stocks which are syntbesised from high volume hydrocarbon intermediates. For example, polyalphaolefin base fluids are synthesised from ethylene. Some, however, start with very basic raw materials. for example, silicone base fluids are made from sand (SiO2), require considerable energy, and there are many steps in their manufacture including handling of very corrosive materials. These variable manufacturing requirements account for the broad price range for synthetics and the much higher price for the ‘exotics’ such as fluorosilicones. Unlike mineral oil base stocks, which are a complex mixture of naturally‐occurring hydrocarbons refined from crude oil, synthetic base stocks are man‐made, having controlled molecular structure with predictable properties. As with all present‐day fluid lubricants, synthetics are formulated by combining the base stocks with selected additives.
The design of an electromagnet needle (EMN) has been numerically optimized based on finite element analysis of the detailed interaction between an EMN and a typical superparamagnetic microparticle. The nonlinear magnetization curves of the core materials and particles are considered; the model calculates the force acting on the particle without far-field simplifications. The EMN optimized for maximum force per unit of heating power generates over 40 000 times the force per unit of heating power of typical optical tweezers. The EMN optimized for a fixed high power level produced 56.7nN, a ten-fold improvement over prior EMNs.
Explosions of coal dust are a major safety concern within the coal mining industry. The explosion and subsequent fires caused by coal dust can result in significant property damage, loss of life in underground coal mines and damage to coal processing facilities. The United States Bureau of Mines conducted research on coal dust explosions until 1996 when it was dissolved. In the following years, the American Society for Testing and Materials (ASTM) developed a test standard, ASTM E1226, to provide a standard test method characterizing the "explosibility" of particulate solids of combustible materials suspended in air. The research presented herein investigates the explosive characteristic of Pulverized Pittsburgh Coal dust using the ASTM E1226-12 test standard. The explosibility characteristics include: maximum explosion pressure, (P max ); maximum rate of pressure rise, (dP/dt) max ; and explosibility index, (K st ). Nine Pulverized Pittsburgh Coal dust concentrations, ranging from 30 to 1,500 g/m 3 , were tested in a 20-Liter Siwek Sphere. The newly recorded dust explosibility characteristics are then compared to explosibility characteristics published by the Bureau of Mines in their 20 liter vessel and procedure predating ASTM E1126-12. The information presented in this paper will allow for structures and devices to be built to protect people from the effects of coal dust explosions.
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