Alternative Heat Treatment

The great advantage of steel as an engineering material is its versatiUty. Properties can be controlled and changed by heat treatment. Thus, if steel is to be formed into some intricate shape, it can be made very soft and ductile by heat treatment on the other hand, alternative heat treatments can also impart high strength. 

Austempering. Lower bainite is generally as strong as and somewhat more ductile than tempered martensite. Austempering, which is an isothermal heat treatment that results in lower bainite, offers an alternative heat treatment for obtaining optimum strength and ductility if the specimens are sufficiently small. 

The testpiece assembly shall be prepared from a mild steel containing not more than 0.20%C, 0.35%Si, 0.05%S. Prior to use the testpiece shall be degassed at a temperature and time sufficient to remove all hydrogen, e.g. 650 °C for 1 hour. If these conditions are not suitable, reference should be made to Fig. 5.2-5.8 to select an alternative heat treatment. 

A second development has been the move toward cell-free extracts by the deUberate lysis of cells to overcome simultaneously transport as well as compartmentaUzation hmitations [18]. However, the resultant catalyst soup is rich in other enzymes, necessitating the addition of inhibitors (or alternatively using genetic engineering to massively overexpress the desired enzymes over other proteins). Alternatively heat treatment can be used in cases where thermostable isoenzymes are available. Likewise, cell debris is present in the reaction medium, necessitating the combination of microfiltration as well as ultrafiltration for recovery (and potential reuse). 

Lipoproteins may denature on heating and if present during pasteurization can result in the formation of haze or turbidity in the final product. This material was removed traditionally by filtration through asbestos (qv) sheets (6) however, health hazards associated with asbestos have led to its replacement by alternative filter materials (23,37,193). These media have been less effective than asbestos and further measures have been required to ensure the visual clarity of albumin products, eg, further filtration developments for Hpid removal (194), preferential denaturation of contaminants using in-process heat treatment, and anion-exchange chromatography (49). 

Choices of alternative materials. Corrosion probes are carefully chosen to be as close as possible to the alloy composition, heat treatment, and stress condition of the material that is being monitored. Care must be taken to ensure that the environment at the probe matches the service environment. Choices of other alloys or heat treatments and other conditions must be made by comparison. Laboratory testing or coupon testing in the process stream can be used to examine alternatives to the current material, but the probes and the monitors can only provide information about the conditions which are present during the test exposure and cannot extrapolate beyond those conditions. 

Seek alternatives to chlorine for water treatment and disinfecting applications. For example, sodium hypochlorite has been used both in industrial and municipal water treatment applications (Somerville, 1990). Other alternatives include calcium hypochlorite, ozone, ultraviolet radiation and heat treatment (Negron, 1994 Mizerek, 1996). 

In view of the difficulties in controlling the electroplating of speculum and bronze coatings, alternative preparation routes through the heat treatment of duplex tin and copper electroplated finishes have been proposed. ... 

Thiopyranopyrrolizines can be prepared readily from the enamine 170 upon treatment with DMAD. Alternatively, heating of the thiacyclooctadiene derivative 171 in methanol gives the same tricycle 172, but this time as a 5 2 mixture with the (Z,E)-isomer of the precursor 171. These reactions probably involve the the intermediacy of an unstable cyclobutene and/or a zwitterionic diene, as shown in Scheme 51 <1984JA1341>. 

Methyl bromide has been identified as an ozone-depleting substance and is being gradually removed from world markets. Current legislation and plans call for the elimination of methyl bromide in most industrial countries by 2005, with possible exemptions for quarantine (UNEP, 1996). Currently there is an extensive search worldwide for products that are alternatives to methyl bromide (Kawakami, 1999). These alternatives are broadly defined and include components of management plans such as sanitation, monitoring, contact insecticides, heat treatments, and modified atmospheres, in addition to new fumigants (Batchelor, 1998). 

Heating an assembly in a furnace should be used when practical however, the size or shape of the unit or the adverse effect of a desired heat treatment on one or more components, where dissimilar materials are involved, may dictate alternative procedures. 

When warranted by experience or knowledge of service conditions, alternative methods of heat treatment or exceptions to the basic heat treatment provisions of para. GR-3.6.1 may be adopted as provided in paras. GR-3.7.1 and GR-3.7.2. 

Spiced Layer Cake. Investigation was undertaken to evaluate navy bean hulls as an alternative source of dietary fiber in spice-flavored layer cakes and to compare hull flour from beans with no heat treatment to hull flour from beans roasted for 2 min at 240°C. Results of the objective analyses performed on both the batter and the cakes indicated that the addition of 15% navy bean hulls resulted in a thicker batter, due to the high water absorbancy of the hulls however, only the batter containing the unroasted hulls was significantly more viscous than the control batter. Cakes prepared with the roasted navy bean hulls tended to be slightly more... 

Few differences were attributed to roasting of the navy bean hulls however, color of the hulls improved with heat treatment. Cakes prepared with either unheated or roasted bean hulls compared favorably to the control. Consequently, navy bean hulls are an acceptable source of dietary fiber in a flavored cake. More research should be initiated to investigate alternative uses for navy bean hulls as a dietary fiber source. 

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