Safe chemical reaction scale up

2005 ◽  
Vol 12 (6) ◽  
pp. 29-35 ◽  
Author(s):  
Dennis C. Hendershot ◽  
Aaron Sarafinas
Keyword(s):  
MRS Bulletin ◽  
1994 ◽  
Vol 19 (1) ◽  
pp. 14-19
Author(s):  
Ikuo Sawada ◽  
Hiroyuki Tanaka ◽  
Masahiro Tanaka

Computational fluid dynamics was born principally in the aerospace field as a method for fluid flow and heat transfer research methods following experimental and analytical approaches. Along with progress in the cost performance of computers, computational fluid dynamics is now establishing itself as a tool to improve production processes and product quality in the steel, nonferrous metals, glass, plastics, and composite materials industries.Materials manufacturers use computational fluid dynamics for diverse purposes:1. Reduction in experimental conditions and costs;2. Detailed analysis of mechanisms with multifaceted information unobtainable through experimentation;3. Universal tool for scale-up; and4. Evaluation of novel processes.It can be readily imagined that accuracy, flexibility, and other requirements of computational fluid dynamics should vary with specific applications.Fluids generally observed in materials manufacturing processes are molten materials such as metal, glass, and plastics, and gases for stirring and refining. In the flow of such fluids, materials quality and process characteristics are governed by the following:1. Transport phenomena in the bulk region (where fluid flow is normally turbulent);2. Chemical reaction at interfaces;3. Transport phenomena in boundary layers near the interfaces; and4. Complex coupled phenomena (heat transfer, diffusion, chemical reaction, phase transformation like solidification, free surface, electromagnetic force, and bubble flow).


Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.


Author(s):  
Dai Dalin ◽  
Guo Jianmin

Lipid cytochemistry has not yet advanced far at the EM level. A major problem has been the loss of lipid during dehydration and embedding. Although the adoption of glutaraldehyde and osmium tetroxide accelerate the chemical reaction of lipid and osmium tetroxide can react on the double bouds of unsaturated lipid to from the osmium black, osmium tetroxide can be reduced in saturated lipid and subsequently some of unsaturated lipid are lost during dehydration. In order to reduce the loss of lipid by traditional method, some researchers adopted a few new methods, such as the change of embedding procedure and the adoption of new embedding media, to solve the problem. In a sense, these new methods are effective. They, however, usually require a long period of preparation. In this paper, we do research on the fiora nectary strucure of lauraceae by the rapid-embedding method wwith PEG under electron microscope and attempt to find a better method to solve the problem mentioned above.


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