Due care

It is essential to use dry apparatus and reagents lower yields are frequently obtained, particularly on humid days, unless due care is taken. 

SemiempiricalIsotherm Models. Some of these models have been shown to have some thermodynamic inconsistencies and should be used with due care. Nevertheless, they have each been found to be useful for data correlation and interpolation, as well as for the calculation of some thermodynamic properties. 

Salts. In addition to the dangers of perchlorate salts, other salts such as nitrates, azides and diazo salts can be hazardous and due care should be taken when these are dried. Large quantities should never be prepared or stored for long periods. 

Caution Crown ethers may be toxic. Due care should be exercised in the preparation and handling of l8-croum-6. An explosion has been reported... 

Provided due care is taken with respect to predrying and to crazing tendencies, polycarbonates may also be thermoformed, used for fluidised bed coating and machined and cemented. Like metals, but unlike most thermoplastics, polycarbonates may be cold formed by punching and cold rolling. Cold rolling can in fact improve the impact resistance of the resin. 

The standard requires product safety to be addressed in the supplier s design control and process control policies and practices with special attention to due care and means to minimize potential risks to employees, customers, users, and the environment. 

As is stated in the standard, all characteristics are important and need to be controlled. However, some need special attention as excessive variation may affect product safety, compliance with government regulations, fit, form, function, appearance, or the quality of subsequent operations. Designating such characteristics with special symbols alerts planners and operators to take particular care. It also alerts those responsible for dispo-sitioning nonconforming product to exercise due care when reaching their decisions. 

Some catalysts, such as Raney nickel, are pyrophoric in themselves and will ignite when brought into contact with air. Due care should be taken in handling them. They are best kept wetted. 

Criticisms of the KS test An extensive collaborative trial was carried out on the KS test and the conclusion (Cowen, 1978) was that the test was suitable for white and clear, soluble disinfectants providing due care was taken in interpreting the pass concentration. Further modification ofthe test is necessary before it can be applied to... 

Commercially, lead azide is usually manufactured by precipitation in the presence of dextrine, which considerably modifies the crystalline nature of the product. The procedure adopted is to add a solution of dextrine to the reaction vessel, often with a proportion of the lead nitrate or lead acetate required in the reaction. The bulk solutions of lead nitrate and of sodium azide are, for safety reasons, usually in vessels on the opposite sides of a blast barrier. They are run into the reaction vessel at a controlled rate, the whole process being conducted remotely under conditions of safety for the operator. When precipitation is complete, the stirring is stopped and the precipitate allowed to settle the mother liquor is then decanted. The precipitate is washed several times with water until pure. The product contains about 95% lead azide and consists of rounded granules composed of small lead azide crystals it is as safe as most initiating explosives and can readily be handled with due care. 

So far, no systematic work has been done on the use of recyclable, solid-phase catalysts in cross-coupling reactions. Most of the examples have been obtained for cross-couplings with either arylboronic acids or terminal acetylenes. It should be noted, however, that due care should be exercised when interpreting results on the cross-coupling of arylboronic acids with aryl iodides, as this extremely facile reaction can be catalyzed by practically any palladium-containing material, including trivial Pd black,481 e.g., as a sediment on the reaction vessel. Therefore, this reaction cannot serve as a reliable test for comparison between different catalytic systems. 

The data presented in this book is intended as a guide only. Whilst due care has been taken in the compilation of this information, it is published on the basis that no responsibility or liability shall attach to Rapra Technology Limited or its employees arising out of or in connection with the utilisation in any form of the material contained within it. 

Tetrachloroethane is a toxic substance it should be handled with due care. 

A useful fingerprint of an active TS-1 catalyst is the particle size of the titanosilicate (<0.4 pm). Although the particle size influences the catalytic activity of all molecular sieves, it is especially so in the case of TS-1 and due care should be exercised in comparing samples varying in particle size (89,90). 

Caution AgC104 is potentially explosive and should be used with due care. It may often be replaced by AgOTf or AgAsF6. 

There are a number of possible explanations for the formation of more than one photodimer. First, due care is not always taken to ensure that the solid sample that is irradiated is crystallographically pure. Indeed, it is not at all simple to establish that all the crystals of the sample that will be exposed to light are of the same structure as the single crystal that was used for analysis of structure. A further possible cause is that there are two or more symmetry-independent molecules in the asymmetric unit then each will have a different environment and can, in principle, have contacts with neighbors that are suited to formation of different, topochemical, photodimers. This is illustrated by 61, which contrasts with monomers 62 to 65, which pack with only one molecule per asymmetric unit. Similarly, in monomers containing more than one olefinic bond there may be two or more intermolecular contacts that can lead to different, topochemical, dimers. Finally, any disorder in the crystal, for example due to defective structure or molecular-orientational disorder, can lead to formation of nontopochemical products in addition to the topochemical ones formed in the ordered phase. This would be true, too, in those cases where there is reaction in the liquid phase formed, for example, by local melting. 

We sometimes find that the end point is still elusive, even with due care and patience. In such cases, a Gran plot may help - a plot of log,o (emf) against volume will be linear (or at least, passably linear), and the volume at equivalence is then given by the intercept on the jc-axis. 

This material may be further purified (m.p. 99.5-100.0°) by recrystallization from pentane or methanol, or by sublimation at 85° (60 mm.). Owing to the unusually high vapor pressure of this product, large losses may be encountered on recrystallization or sublimation unless due care is exercised. 

Stepwise oxidation of organic snbstrates is often carried out with thainthreniumyl perchlorate. This oxidant will be encountered in many cases dnring the citing of materials in the following chapters. However, first, a safety warning shonld be pnt. It is a shock-sensitive solid that mnst be handled only on a small scale and with due care. 

By comparing Eq. (2.153) to Eq. (2.78) for the desired diffusion equation, while taking due care with the order of derivatives, we hnd that the two forms of the diffusion equation become equivalent if and only if... 

Microbial sensors offer a number of assets, namely (a) they are less sensitive to inhibition by solutes and more tolerant to suboptimal pH and temperature values than are enzyme electrodes b) they have longer lifetimes than enzymes and (c) they are less expensive than enzyme electrodes as they require no active enzyme to be isolated. On the other hand, they lag behind enzyme electrodes in a few other respects thus, (a) some have longer response times than their enzyme counterparts b) baseline restoration after measurement typically takes longer and (c) cells contain many enzymes and due care must be exercised to ensure adequate selectivity e.g. by optimizing the storage conditions or using specific enzyme reactions) —some mutant microorganisms lack certain enzymes. 

However, not all reactive intermediates are kind enough to provide spectroscopic signatures that allow their immediate and unambiguous identification, and it is therefore often necessary to compare those signatures to ones obtained by means of modeling calculations (the reader may note that with this we leave the realm of forensic analogy that we have perhaps already stretched too far). In fact, many recent matrix isolation studies owe their success to the tremendous advances in the field of computational chemistry, and to the increased availability of the hard- and software required to carry out such calculations. This simation provides an opportunity for much creative work in the field of reactive intermediates, but it also implies an obligation on the part of those who use such methods to apply them with due care and circumspection. 

Since the formation of the red by-product appears to depend upon the time during which the catechol is heated with hydrobromic acid, it is well to carry out the reaction as rapidly as possible due care must be taken, however, that the temperature at the head of the column does not rise prematurely above 95°... 

Caution. Although no problems were encountered in the syntheses that follow, transition metal perchlorates are potentially explosive and should be prepared in small quantities. Due care must be taken when handling perchlorate and cyanide salts. All materials are commercial samples of reagent grade unless indicated otherwise. 

Under the negligence rule, injurers are liable for damages caused by their behavior only if they don t exercise due care, and victims are responsible for other damages. Under strict liability with contributory negligence, the opposite is true injurers are responsible for all damages unless the victims did not exercise due care. Under strict liability, injurers are responsible for all damages their products cause, period. 

Accidents in which care levels of both firms and customers affect damages are called bilateral accidents. Strict liability with contributory negligence will efficiently manage risks in bilateral accidents if customers are aware of the courts due-care standard. Under strict liability with contributory negligence, consumers must engage in precautions that the court determines are cost-effective. The damages that remain after that level of care is taken are the firm s responsibility. This increases product prices and reduces purchases, an important method of accident control (Shavell 1987, 54). 

In contrast, if technologically sophisticated products are subject to the negligence rule, several difficulties impede efficiency. First, courts must determine appropriate due-care levels for firms, a difficult matter in all situations but even harder when technical or engineering information is involved. Second, even if courts select an... 

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