Recurring

Equation II-7 is the fundamental equation of capillarity and will recur many times in this chapter. 

It remains to investigate the zeros of Cg t) arising from having divided out by. The position and number of these zeros depend only weakly on G, but depends markedly on the fomi that the time-dependent Hamiltonian H(x, () has. It can be shown that (again due to the smallness of ci,C2,...) these zeros are near the real axis. If the Hamiltonian can be represented by a small number of sinusoidal terms, then the number of fundamental roots will be small. However, in the t plane these will recur with a period characteristic of the periodicity of the Hamiltonian. These are relatively long periods compared to the recurrence period of the roots of the previous kind, which is characteristically shorter by a factor of... 

The enzyme catalyzed reactions that lead to geraniol and farnesol (as their pyrophosphate esters) are mechanistically related to the acid catalyzed dimerization of alkenes discussed m Section 6 21 The reaction of an allylic pyrophosphate or a carbo cation with a source of rr electrons is a recurring theme m terpene biosynthesis and is invoked to explain the origin of more complicated structural types Consider for exam pie the formation of cyclic monoterpenes Neryl pyrophosphate formed by an enzyme catalyzed isomerization of the E double bond m geranyl pyrophosphate has the proper geometry to form a six membered ring via intramolecular attack of the double bond on the allylic pyrophosphate unit... 

The recurring para-substituted benzene rings and sulfur atoms form a symmetrical rigid backbone. 

In addition to alcohoHc fermentation, a malolactic fermentation by certain desirable strains of lactic acid bacteria needs to be considered. Occasionally, wild strains produce off-flavors. Malolactic fermentation is desirable in many red table wines for increased stabiUty, more complex flavor, and sometimes for decreased acidity. Selected strains are often added toward the end of alcohoHc fermentation. AH the malic acid present is converted into lactic acid, with the resultant decrease of acidity and Hberation of carbon dioxide. Obviously this has more effect on the acidity the more malic acid is present, and this is the case in wine from underripe, too-tart grapes. Once malolactic fermentation has occurred, it does not recur unless another susceptible wine is blended. 

Decision. Whereas a conclusion that conditions are to some degree unsafe requires that something be done, what should be done depends on the range and impact of the conclusion. The problem may be easy to correct, or it may no longer exist. The data may describe past conditions that do not presendy exist but may recur. It may be that the only possible decision is to undertake significant exposure reduction efforts at great cost. The possibiUty of each decision should have been anticipated when the evaluation was plarmed so that the data in hand support the decision that must be made. 

Actual water treatment challenges are multicomponent. For example, contamination of groundwater by creosote [8021-39-4], a wood (qv) preservative, is a recurring problem in the vicinity of wood-preserving faciUties. Creosote is a complex mixture of 85 wt % polycycHc aromatic hydrocarbons (PAHs) 10 wt % phenohc compounds, including methylated phenols and the remaining 5 wt % N—, S—, and O— heterocycHcs (38). Aqueous solutions of creosote are therefore, in many ways, typical of the multicomponent samples found in polluted aquifers. 

Fig. 3. Representation of the nine principal folds which recur in protein stmctures, where the codes of the representative proteins taken from the Brookhaven Protein Data Bank (PDB) (17) are given in parentheses (18) (1) globin (Ithb) (2) trefoil (lilb) (3) up—down (256b) (4) immunoglobulin folds...

Anxiety disorders and insomnia represent relatively common medical problems within the general population. These problems typically recur over a person s lifetime (3,4). Epidemiological studies in the United States indicate that the lifetime prevalence for significant anxiety disorders is about 15%. Anxiety disorders are serious medical problems affecting not only quaUty of life, but additionally may indirecdy result in considerable morbidity owing to association with depression, cardiovascular disease, suicidal behavior, and substance-related disorders. 

Polyoxyethylene Surfactants. Polyoxyethylene-solubilized nonionics (ethoxylates) were iatroduced ia the United States as textile chemicals shordy before 1940. The solubiUty of these compounds derives from recurring ether linkages ia a polyoxyethylene chain... 

Two types of approaches are available. In one, the fabric is padded with the cross-linker finish, dried, then sent to the garment cutter. The garments are then pressed and cured. In the second, the fabric is cured in fabric form, then fabricated into garments. It is then pressed and recured in hot-head presses. This double curing is particularly hard on the ceUulosic fiber in terms of strength and abrasion resistance. 

Although delayed cure cotton was the primary impetus in the rise to durable-press performance, the emergence of DP blends had the effect of reducing the importance of a tme delayed cure. The industry tended to revert back to precure fabrics and the utilisation of hot-head presses to set in creases, using the thermoplastic characteristics of the synthetic components as weU as a touch of recure from the hot-head presses. 

Two forms of lymphatic filariasis are found in India. The Bancroftian form is the most common and accounts for more than 90% of the disease whereas Bmgian filariasis accounts for the rest. In a study carried out in India (6) in 40 patients with Wuchereria Bancwfti filariasis treated with single oral doses, all of the dose levels chosen (25, 50, 100, and 200 mg/kg) were efficacious in clearing microfilariae from the blood of all patients treated. However, after three months some microfilaria recurred in the blood of most patients (Table 5). Further studies are planned and some are underway using different doses and regimens. Ivermectin still appears to hold promise as a new treatment for lymphatic filariasis. 

Nylon—any long-chain synthetic polyamide having recurring amide groups as an integral part of the polymer chain. 3.8-9.2 E F-P G F-P G 1.14 225... 

At certain speeds, rotating masses become dynamicatty unstable and cause deflection and vibration in the rotor w hich may damage the motor. The speed at w hich such instability occurs is known as critical speed and occurs at different multiples of the rated speed. The masses must therefore rotate within 20T beknv or above the critical speeds to avoid such a situation. These vibrations settle down again at higher speeds above critical and recur at the next higher critical speed. 

One recurring problem has been that a perceived shortage of a particular material has led to plans by more than one company to build large plants to produce that material, so that a shortage is then followed by a period of severe excess capacity and depressed polymer prices. 

Kletz, T.A. (1993) Lessons from Disasters How Organisations Have No Memory and Accidents Recur, Institutional Chemical Engineers, Rugby. 

Firms should be asked to provide references from clients who have received comparable services. In exploring references, it is useful to ask about long-term follow-up. After the contract was completed, did the contractor remain in contact with the client to ensure that problems did not recur ... 

Note that costs and benefits can be either one-time or recurring. Be sure to include them appropriately in your analysis. Follow these basic rules when gathering information and including costs in the ROI analysis ... 

Group of plastics composed of resins based on saturated polymeric esters whereby the recurring ester groups are an integral part of the primary polymer chain and the ester groups exist in cross-links that are present between chains. 

Group of plastics composed of resins derived principally from polymeric esters that have recurring polyester groups in the main polymer chain. These polyester groups are crosslinked by carbon/carbon bonds. 

Nylon plastics Group of plastics comprised of resins that are primarily long-chain synthetic polymeric amides. These have recurring amide groups as an integral part of principal polymer chain. 

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