Fabrication methods/technologies

The rapid expansion of reverse osmosis technology during the past two decades has resulted in the development of a variety of new membranes. Unique polymer systems and fabrication methods have led to the production of membranes with significantly improved performance and reliability. In spite of these developments little is known about chemical sensitivity or life expectancy of reverse osmosis membranes used in desalting applications. Manufacturers are consequently reluctant to guarantee their products for long runs especially in unique chemical environments. 

AECL has evaluated some of the basic information and development requirements in some detail (24, 25) and has outlined the type of fuel recycle development program which would be required. It would involve research and development of thorium fuels and fuel fabrication methods, reprocessing, demonstration of fuel management techniques and physics characteristics in existing CANDU reactors and demonstration of technology in health, safety, environmental, security and economics aspects of fuel recycle. 

Thin film technology is becoming one of the important technologies today. While there are infinite varieties of thin film fabrication methods, most amorphous thin films seem to exhibit fractal-like atomic structures. Depending on the fabrication conditions, a thin film grows on the substrate into columnar structures with many voids interdispersed in the thin film.80 These structures can be seen in the field ion microscope, and compositional variation can be analyzed with the atom-probe. In addition, formation of atomic clusters inside the thin film can be substantiated with the observation of a large fraction of cluster ions in field evaporation by the atom-probe. 

Concurrently with the advance in fabrication methods came the independent improvement of pumping practice. The positive displacement pump, predominantly the reciprocating steam-driven type, was commonly used in 1925 to transfer liquids most rein PROGRESS IN PETROLEUM TECHNOLOGY ... 

As already mentioned, the concepts of integration and miniaturization are not new in separation science, but the tools at our disposal for the realization of such systems have changed dramatically with the advent of micromechanical fabrication methods. The advantages of this technology are best appreciated by a closer look at earlier attempts to construct integrated small volume analysis systems using conventional techniques. 

The first step in caring for museum fabrics is to understand them as materials physical and chemical properties of fibers, yams, and fabrics the fabrication method and technique the design layout and color trend factors related to use and the pre- and postacquisition state. Subsequent studies should try to date the objects and determine technical and material peculiarities of each provenance and establish history and classification of fabric technology. Here, briefly, the nature of natural fibers and dyes is discussed since they form the majority of museum fabrics at present. 

The technology of ETA cells is not yet mature, and future improvements in their efficiency can reasonably be expected. Modelling calculations (Taretto and Rau, 2005) indicate that 15% efficient CdTe ETA cells are possible even at electron diffusion lengths as low as 10 nm, provided that the built-in voltage is optimised to restrict recombination over the working bias range of the cell. If efficiency improvements of this order can be achieved and fabrication methods can be satisfactorily scaled up, ETA cells could offer a low-cost, stable alternative to traditional photovoltaic cells and dye-sensitised solar cells. 

Very little information concerning fabrication methods and machinery directly is available in the form of dissertations. Equipment for fabricating plastics is expensive and is difficult for research institutions to obtain and maintain with the latest design features. Also, the needs of industry are considerably more specific than the work which can be handled by students of basic technology. For this reason the development of equipment and methods on the manufacturing level usually is done in industrial plants rather than in educational institutions. Dissertations are not likely to prove to be a fertile field for fabrication equipment development ideas. 

New research shows that ultraviolet avalanche photodiodes offer the high gain, reliability and robustness needed to detect anthrax and other bioterrorism agents in the air. The fabrication methods and device characteristics were described at the fiftieth Electronic Materials Conference in Santa Barbara on June 25, 2008. Details of the photodiodes were also published in the February 14,2008 issue of the journal Electronics Letters and the November 2007 issue of the journal IEEE Photonics Technology Letters. 

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