Heat tolerance, decreasing

Hydrogenation of a fat and oil basestock increases the oxidative stability. As a rule, the lower the base IV the better the oxidative stability. However, as base hardness is increased, the level of hardstock required to reach a desired consistency must decrease. Hardstock reduction reduces the plastic range and heat tolerance. Therefore, oxidative stability improvements are achieved at the expense of plasticity and a wide plastic range can be at the expense of oxidative stability. The extent that one attribute can be compromised to improve another must be determined by the requirements of the intended food product. Oxidative stability is directly related to the level and type of unsaturated fatty acids present therefore, oxidative stabihty results do not average. For example, a 50 50 blend of a 40-hour AOM basestock and a 100-hour AOM basestock will not have an AOM stabihty of 70 hours, but rather will be closer to the component with the lower AOM stabihty (152). 

Casualties with side effects from chemical agent antidotes. Some of the available antidotes may have undesirable side effects when taken inappropriately, or in large enough quantities. Atropine, for instance, causes decreased heat tolerance at a dose of 1 mg. Higher doses may cause tachycardia, dryness of the mouth, and decreased sweating. Medical personnel must be aware of the side effects of the available antidotes and be alert for their appearance. 

Decrease tissue heat tolerance to facilitate cell death... 

Methods of decreasing heat tolerance of tissues to optimize the results of RF ablation are experimental at present. They include prior cellular injury from chemotherapy or radiation and prior hypoxia caused by vascular occlusion or antiangiogenesis factors (Goldberg et al. 2000b). 

In consequence, different strategies are conceivable and/or applicable to enhance the ablation process (1) improving heat conduction, (2) decreasing heat tolerance of the tumour and (3) increasing energy deposition. 

As mentioned earlier and established previously [34, 35, 44], it is well known that the degree of fatty acyl saturation in lipid species is closely related to the heat tolerance. In the studies on heat acclimation, it was also found that an increased level of fatty acyl saturation as indicated by the double-bond index in galactolipids from wild-type plants after heat acclimation is also present [6, 17]. Specifically, the double-bond index of DGDG species is reduced from 2.58 to 2.34, and the double-bond index of MGDG decreased from 2.95 to 2.84 after a heat acclimation for 24 h at 38 C. Increases in the levels of fatty acyl saturation among other major... 

Hyperthermia. - The ability to tolerate heat stress decreases with age. EPR studies on frozen liver samples from rats have revealed changes in the intensity of signals from endogenous metals and a semiquinone species. Related studies have shown that hyperthermia induces the appearance of signals from ceruloplasmin, haem-coordinated NO and a semiquinone species in the blood. These changes were attributed to increased NOS and XO activities and were proposed to underlie the observed systemic responses e.g. hypotension). Other workers have examined the mechanisms by which radicals enhance the induction of apoptosis in human lymphoma cells exposed to hyperthermia. ... 

Typically for any boiler design or type, any tolerance for deposition can be expected to decrease with increase in operating pressure. A practical tolerance limitation for the thickness of boiler deposits on heat transfer surfaces is given in Table 4.2. 

Achieving steady-state operation in a continuous tank reactor system can be difficult. Particle nucleation phenomena and the decrease in termination rate caused by high viscosity within the particles (gel effect) can contribute to significant reactor instabilities. Variation in the level of inhibitors in the feed streams can also cause reactor control problems. Conversion oscillations have been observed with many different monomers. These oscillations often result from a limit cycle behavior of the particle nucleation mechanism. Such oscillations are difficult to tolerate in commercial systems. They can cause uneven heat loads and significant transients in free emulsifier concentration thus potentially causing flocculation and the formation of wall polymer. This problem may be one of the most difficult to handle in the development of commercial continuous processes. 

Differences in sample size and composition can also affect heating rates. In the latter case, this particularly applies when ionic conduction becomes possible through the addition or formation of salts. For compounds of low-molecular weight, the dielectric loss contributed by dipole rotation decreases with rising temperature, but that due to ionic conduction increases. When working under pressure, it is essential to measure pressure. This can be used for reaction control. If pressures fall beyond acceptable upper and lower limits or the rate of pressure rise exceeds a tolerable value, operating software should automatically shut down the machine. In combination with efficient cooling this approach can avoid thermal runaways near their onset. 

The absorption of species from the atmosphere is common to all electrolyte solutions and clearly the absorption of water is the biggest issue. This is not solely confined to ionic liquids, however, as all electroplaters who deal with aqueous solutions of acids know, if the solution is not heated then the tank will overflow from absorption of atmospheric moisture after some time. In the aqueous acid the inclusion of water is not a major issue as it does not significantly affect the current efficiency or potential window of the solution. Water absorption is also not such a serious issue with eutectic-based ionic liquids and the strong Lewis acids and bases strongly coordinate the water molecules in solution. The presence of up to 1 wt.% water can be tolerated by most eutectic-based systems. Far from having a deleterious effect, water is often beneficial to eutectic-based liquids as it decreases the viscosity, increases the conductivity and can improve the rate of the anodic reaction allowing better surface finishes. Water can even be tolerated in the chloroaluminate liquids to a certain extent [139] and it was recently shown that the presence of trace HQ, that results from hydrolysis of the liquid, is beneficial for the removal of oxide from the aluminum anode [140]. 

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