CAD/CAE application in centering EDM machine design
The centering EDM machine can be completed online centering hole processing. Traveling by the high speed line feed mechanism, low speed line feed mechanism, rotating body, lifting body, auto body for baseball, Swing components, such as buffer baffle. The advantage of this approach is: a small device, processing consistency, and efficient processing, process automation, and effective in the elimination round billet rolling wear puncher into a capillary formed by the iron handle. In order to design the machine, the CAD/CAE technology, basing on the conception of global structure, dwelling on selecting motor, 3D modeling with solidworks, dynamic simulation with cosmosmotion, and analysis the key parts using finite element method were presented.
Development of new material and heat treatment for tools ensuring high performance in hot seamless tube rolling
Abstract A new technology has been developed to improve the life of tools used for high temperature steel rolling in seamless tube manufacturing. It is a joint technology combining a new chemical composition and a special heat treatment. The new steel tool material has high Cr, C, and Ni contents compared with those of the conventional tools in order to increase the volume fraction of carbide which increases wear resistance. Through the new heat treatment, the macroscopic distribution pattern of eutectic carbide changes from meshlike to granular form increasing resistance against crack propagation. The validity of the results in the laboratory has been verified on the production line.
The Liverpool Cholera Epidemic of 1832 and Anatomical Dissection--Medical Mistrust and Civil Unrest
Asiatic cholera reached Britain for the first time in late 1831, with the main epidemic occurring during 1832. The disease caused profuse diarrhea, severe dehydration, collapse, and often death. There was widespread public fear, and the political and medical response to this new disease was variable and inadequate. In the summer of 1832, a series of "cholera riots" occurred in various towns and cities throughout Britain, frequently directed against the authorities, doctors, or both. The city of Liverpool, in the northwest of England, experienced more riots than elsewhere. Between 29 May and 10 June 1832, eight major street riots occurred, with several other minor disturbances. The object of the crowd's anger was the local medical fraternity. The public perception was that cholera victims were being removed to the hospital to be killed by doctors in order to use them for anatomical dissection. "Bring out the Burkers" was one cry of the Liverpool mobs, referring to the Burke and Hare scandal four years earlier, when two men had murdered people in Edinburgh in order to sell their bodies for dissection to the local anatomy school. This issue was of special concern to the Liverpool citizenry because in 1826, thirty-three bodies had been discovered on the Liverpool docks, about to be shipped to Scotland for dissection. Two years later a local surgeon, William Gill, was tried and found guilty of running an extensive local grave-robbing system to supply corpses for his dissection rooms. The widespread cholera rioting in Liverpool was thus as much related to local anatomical issues as it was to the national epidemic. The riots ended relatively abruptly, largely in response to an appeal by the Roman Catholic clergy read from church pulpits, and also published in the local press. In addition, a respected local doctor, James Collins, published a passionate appeal for calm. The Liverpool Cholera Riots of 1832 demonstrate the complex social responses to epidemic disease, as well as the fragile interface between the public and the medical profession.