in the conditions in which terrorist attacks on facilities and civilian places increase more and more attention to design of structures against impact loads of explosion is more important and needs special considerations. study of nature of blast loads and methods of applying it on the structure is one of the important problems. explosion is a sudden and rapid release of a great amount of energ...

aa8090 is an extra light and deformable group of lithium containing aluminum alloys which have recently replaced some aerospace aluminum alloys, such as 2000 and 7000 series, due to their higher elastic modulus and lower specific weight. in this study, aa8090 matrix composites containing 3, 6 and 9 vol.% sic were cast using a modified stir casting method. the casting billets were deformed thoug...

A protonmotive force (pmf) across the cell's inner membrane powers the flagellar rotary motor of Escherichia coli. Speed is known to be proportional to pmf when viscous loads are heavy. Here we show that speed also is proportional to pmf when viscous loads are light. Two motors on the same bacterium were monitored as the cell was slowly deenergized. The first motor rotated the entire cell body ...

Adhesion and friction between metallic materials are of importance to many dynamic mechanical systems, particularly to those at nanoor micro-scales. Under light loads, friction is mainly dependent on the adhesion between two surfaces in contact, to which valence electrons have the predominant contribution. However, the correlation between the electronic behavior and adhesion as well as friction...

under the contemporary scenario of global climate change and increasing coastal eutrophication, baseline studies of phytoplankton diversity and distribution in relation to habitat conditions constitute the first approach to evaluate potential shifts at the base of the food webs. here we present data of phytoplankton species composition and environmental variables in winter 2006 in a temperate ...

the efficiency of induction motors decreases at light loads. efficiency optimizer control systemsadjust the motor flux value to achieve the best efficiency in a wide range of load variations. reduced fluxoperation has some other benefits such as power factor improvement and torque ripple reduction. the latter isan important issue in a direct torque controlled induction motor drive. in this pape...