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During the last decade, several technological advances have taken place in the construction and fabrication industry in terms of methods, processes and tools which ultimately reduce fabrication time and costs. Fastening of metal plates with bolts and nutes in civil construction of large structures has recently been replaced by self drilling-tapping fasteners. The technique of using a self drilling-tapping fastener not only eliminates use of separate drills and drilling processes, but also eliminates the use of bolts and nuts. In addition, the time to join two plates by a self drilling-tapping fastener is significantly shorter than the time required for joining plates by conventional bolting methods. Although self drilling-tapping fasteners have many advantages, it is equally important that they demonstrate consistent performance in field applications.

A novel design of an air-gap insulated piston has been proposed which is expected to give a longer life compared to the existing designs. The new composite piston is made of a crown piece which is fitted to the base of a piston through a gasket by an interference fitting and locked by oval shaped rivets radially. A steady state two dimensional thermal analysis is performed on the piston to predict the temperature distribution, then a thermo-elastic analysis is performed to obtain thermal stress distribution. Further, a pure mechanical stress analysis is performed on the piston. These analyses are performed on a Aluminum single piece piston, as reference and an air-gap insulated Ultra High Strength Steel piston using finite element method. Constant temperatures are assumed at gas, liner and oil boundaries of the piston. Also, film coefficients on the piston boundaries are kept constant.

Wear characteristics of four bearing materials have been investigated under different sliding conditions. The bearing materials used were CDA 954, CDA 863, CDA 932, and CDA 938. Using a Taber Wear Tester, a cylinder on a flat geometry was used as a tribo contact pair. All bearing materials in the form of a thick cylindrical disk were subjected to combined sliding-rolling motion against a rotating flat disk. The flat disk was either an abrasive disk, or a very soft steel disk, or a hardened steel disk with and without lubrication. Wear was measured as weight loss after several thousand cycles of rotation. Maximum wear of the bearing materials occurred when the counter body was a very soft steel disk. These results together with the wear rate of each bearing material sliding against four different counter bodies are presented. These results are found to be of practical importance in the design and application of journal bearings made of materials used in this investigation.