Drying, optimum

Process Requirements. Typical inside dry-bulb temperatures and relative humidities used for preparing, processing, and manufacturing various products, and for storing both raw and finished goods, are Hsted in Table 1. In some instances, the conditions have been compromised for the sake of worker comfort and do not represent the optimum for the product. In others, the conditions Hsted have no effect on the product or process other than to increase worker efficiency. 

Harvesting ndPretrea.tment. At optimum maturity, the plants are pulled or mowed by hand or machine and, if necessary, threshed to remove seeds. The plants are spread out iu a field to dry. 

If ah of the nonfiltration operations are grouped together into a downtime, assumed to be fixed and known, an optimum filtration time in relation to p can be derived by optimizing the average dry cake production obtained from the cycle. Eor constant pressure filtration and where the medium resistance R and the specific cake resistance are constant, the fohowing equation appHes ... 

A report on the continuous flash pyrolysis of biomass at atmospheric pressure to produce Hquids iadicates that pyrolysis temperatures must be optimized to maximize Hquid yields (36). It has been found that a sharp maximum ia the Hquid yields vs temperature curves exist and that the yields drop off sharply on both sides of this maximum. Pure ceUulose has been found to have an optimum temperature for Hquids at 500°C, while the wheat straw and wood species tested have optimum temperatures at 600°C and 500°C, respectively. Organic Hquid yields were of the order of 65 wt % of the dry biomass fed, but contained relatively large quantities of organic acids. 

Lime stabilization originated in Texas after World War II, and now it is used throughout the world. Lime is most commonly applied at a 4 wt % application or ca 11 kg/m (20 Ib/yd ) for 15 cm of compacted depth. It can be applied dry as hydrated time or granular quicklime or as a wet slurry. Distribution of the latter form is dusfless. Copious amounts (as much as 5—10%) of water are always needed in excess of the optimum moisture content of the soil. Then, a requisite for success is intimate mixing with a rotary mixer, followed by compaction to a minimum of 95% Proctor density. 

Other minor raw materials are used for specific needs. Eumaric acid [110-17-8] the geometric isomer of maleic acid, is selected to maximize thermal or corrosion performance and is the sole acid esterified with bisphenol A diol derivatives to obtain optimum polymer performance. CycloaUphatics such as hydrogenated bisphenol A (HBPA) and cyclohexanedimethanol (CHDM) are used in selective formulations for electrical apphcations. TetrahydrophthaUc anhydride [85-43-8] (THPA) can be used to improve resiUence and impart useful air-drying properties to polyester resins intended for coating or lining apphcations. 

The compounding technique for latex differs from that of dry mbber and is fundamentally simpler. A critical factor of colloidal stabiUty makes necessary that each ingredient is of optimum particle size, pH, and concentration when added as an aqueous dispersion to the latex. Rubber latex is a colloidal aqueous emulsion of an elastomer and natural mbber latex is the milky exudation of certain trees and plants that of greatest commercial importance is the... 

Fast, low temperature curing mbber compounds can be prepared by initial heat prevulcanisation of the Hquid latex and are marketed commercially (Revultex, Doverstrand Corporation). Rubber deposited from these often needs tittle more heat than that required to dry the deposit, to achieve optimum tensile strength and elongation. Such compounds are often used by small companies manufacturing thin-wall dipped medical latex products, such as examination gloves, as few compound preparation facilities are needed by the dipping company. 

Prevulcanised compounds, which have undergone the necessary cross-linkage while in the liquid state, are becoming more popular in industry. Articles made from these can often be merely dried to be adequate for a purpose, but to achieve optimum physical properties it is usually necessary to give the articles a short, low temperature (ca 80°C) cure in an oven. 

Oxane bonds, M—O—Si, are hydroly2ed during prolonged exposure to water but reform when dried. Adhesion in composites is maintained by controlling conditions favorable for equiUbrium oxane formation, ie, maximum initial oxane bonding, minimum penetration of water to the interface, and optimum morphology for retention of silanols at the interface. The inclusion of a hydrophobic silane, such as phenyltrimethoxysilane [2996-92-17, with the organofunctional silane increases thermal stabiUty of the silane and make the bond more water resistant (42). 

Firing. A hot-air oven having forced circulation in a countercurrent mode is used to dry the fermented tea leaves and inactivates the key enzymes required for fermentation. The firing process generally occurs over an 18—20-min period, which is optimum for normal process efficiencies. 

Next, the amalgam must be condensed properly ia the prepared, clean, and dry cavity. In general, the maximum effective load tolerated by the patient should be used on a condenser of optimum size, to remove as much mercury from the mass as possible. The amalgam must be carved to the contour of the lost tooth tissue it is replaciag. 

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