Difference engine

Designing for robustness has also been associated with the DFM guidelines (Russell and Taylor, 1995). Robust design has different meanings to different engineering communities. For example, the three descriptions below focus on three different but connected aspects of product design ... 

The concept of a ductile-to-brittle transition temperature in plastics is likewise well known in metals, notched metal products being more prone to brittle failure than unnotched specimens. Of course there are major differences, such as the short time moduli of many plastics compared with those in steel, that may be 30 x 106 psi (207 x 106 kPa). Although the ductile metals often undergo local necking during a tensile test, followed by failure in the neck, many ductile plastics exhibit the phenomenon called a propagating neck. Tliese different engineering characteristics also have important effects on certain aspects of impact resistance. 

To model is to represent reality, and modeling as an essential task of any engineering activity is always contextual. Within the scope of differing engineer-... 

Desulfurization of other diesel feedstocks from Total Raffinage was also reported by EBC. In these studies, different engineered biocatalysts were used. Two different middle distillate fractions, one containing 1850 ppm sulfur and other containing 650 ppm sulfur, were tested. R. erythropolis sp. RA-18 was used in one experiment and was reported to desulfurize the diesel from 1850 to < 1200ppm sulfur within 24 hours. On the other hand, it removed sulfur from a middle distillate with 650ppm sulfur to below 200 ppm sulfur [222], Various Pseudomonas strains were also tested in this study and reported to remove less amounts of sulfur. A favorable characteristic of the Pseudomonas strains is their inability to form stable emulsions, which can be useful trait for product recovery. 

Results clearly indicated effects of diesel exhausts from different engine operating conditions on the cells already after 1 h of exposure. However, a 1-h continuous exposure to a therapeutic aerosol is probably of limited clinical relevance. To study the effect of drugs administered by typical pharmaceutical single-dose inhalers (MDI, DPI) effective deposition of one puff within the time of one breathing maneuver ( 5 s) is probably more relevant. 

Zeolite particles are incorporated into a number of different engineered forms, including smaU spherical parhcles for fluidized bed appHcations and smaU granules for powdered detergents. Larger forms include extruded peUets with various cross-sectional shapes and beads made by bead-forming processes. 

Inorganic ceramic oxide supports for catalysts, such as alumina and silica, are used extensively in the catalysis industry because they are strong, they can have a range of shapes for different engineering needs and they are economical. They provide high surface areas for catalysis, ranging from 50 to 500 m g and can have pore sizes ranging from 2 to 20 nm in diameter. 

Engineering is a divided profession, and different codes of ethics govern different engineers. Here we compare two very different codes of ethics ... 

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