vibration in the air slide tables of ultra precision machines prevents gaining accuracies within nanometer level. in this work, dissimilar types of internal vibration including small vibrations and pneumatic hammers have been tested and some measures have been offered to reduce their effects. this paper has also proceeded to the vibration tests on the air slide tables built with different numbe...

air pads are applicable in ultra precision machines very much. two main components of these machines, spindle and table, use the advantages of such systems. the performance and efficiency of air pads have big influence on the whole machine quality. parameters affecting pressure distribution of air tables may be considered as, 1) air compressing method, 2) air nozzle diameter, shape, and size, 3...

introduction air pollution is one of the critical challenges in metropolitans around the world. according to world health organization (who), three millions people die from air pollution annually. in some studies mortality costs by air pollution was estimated. social cost of air pollution was estimated 28990 billions rials in tehran city. the mortality cost by air pollution was estimated about ...

During the September 23, 2004 Board hearing on the proposed AB 1493 regulation, a representative of Sierra Research, Inc. (SRI) commented that the Air Resources Board (ARB) staff had overestimated the miles traveled (VMT) in a vehicle’s average lifetime. The assertion was that this had in turn resulted in an overestimation of lifetime fuel savings and an underestimation of the payback period fo...

Recently, a variety of robotic systems have been studied under the umbrella term of modular reconfigurable robotics [7,6]. Unlike conventional fixedmorphology robots, whose performance is usually confined by the operating environment and their own size, modular reconfigurable robots have the potential advantage of being able to change their morphology by rearranging the connectivity of their mo...

However, as described in the following table, the band 2 700-2 900 MHz is allocated worldwide on a primary basis to radionavigation service, used for air surveillance radars (ASR), including radars providing air surveillance and air traffic control, as well as meteorological radars that are afforded equal status to the aeronautical radionavigation system (ARNS) for operation in this band under ...