Specifying agent

Although the low temperature polymerization of methyl methacrylate in polar solvents such as THF was believed to proceed without termination, a more exhaustive investigation55) revealed some slow termination processes resulting from the formation of a, not yet specified agent, supposedly produced in the initiation step. Since the nature of the terminating agent is still unknown it is premature to discuss here the proposed schemes of this termination process. 

Council Directive 88/364/EEC of 9 June 1988 on the protection of workers by the banning of certain specified agents and/or certain work activities (Fourth individual Directive within the meaning of Article 8 of Directive 80/1107/EEC), Official Journal L 179,09/07/1988 P. 0044 - 0047. 

Besides the above-mentioned risk factors related to pregnant or breastfeeding workers, several prohibitions of exposure to particular agents or working conditions have been determined. The EU directive 92/85/EEC provides a list of specified agents, processes, and work conditions in annex II, which are given below ... 

The specifying agent is usually assumed to be a human being, who is in turn assumed to know—even if only informally—the intentions. Moreover, it is usually assumed that the given axioms are consistent with these intentions. 

Specifying agent human or machine often a human being... 

Product of reduction of carbonyl compound by specified reducing agent... 

USP XXII specifies that sodium iodide contains 99—101.5% Nal, calculated on an anhydrous basis (4). It is used iaterchangeably with potassium iodide as a therapeutic agent, except where sodium ion is contraindicated (see Potassium compounds). Intravenous sodium iodide formulations have been used for a variety of diseases, from thyroid deficiency to neuralgia (see Thyroid and antithyroid preparations). However, these solutions are no longer listed ia the XFXUII (4), iadicatiag that their therapeutic value has not been satisfactorily demonstrated. 

Curing Catalysts for A Methylol Agents. Many acid-type catalysts have been used in finishing formulations to produce a durable press finish. Catalyst selection must take into consideration not only achievement of the desked chemical reaction, but also such secondary effects as influence on dyes, effluent standards, formaldehyde release, discoloration of fabric, chlorine retention, and formation of odors. In much of the industry, the chemical suppher specifies a catalyst for the agent so the exact content of the catalyst may not be known by the finisher. 

Vat dyes are water-soluble ki the reduced state but extremely kisoluble ki the oxidi2ed anthraqukione state (see Dyes, anthraquinone). As an example. Figure 2 shows the soluble and oxidi2ed states for Vat Yellow 3, used as a yellow colorant ki several lenses. The water-soluble form of the dye is allowed to diffuse kito the polymer matrix for a specified amount of time. The dye is then treated with a mild oxidi2kig agent and the kisoluble form is precipitated. The tints are extremely colorfast and stable for the life of the lens however, the dyes are unstable ki the soluble form and quite expensive. 

In exposures by inhalation of airborne materials, the dose is the concentration multiplied by the time (CT), and is roughly a constant for any given material and specified effect. The CT value can be used to provide a rough approximation of other combinations of concentration and time which would have about the same effect. Although this concept must be used very cautiously and cannot be applied at extreme conditions of either concentration or time, it is most important in setting limits for airborne contaminants and physical agents in respect to environmental exposures. The worker is exposed for various periods of time, day after day, to the... 

Reference period A specified time period allowed for human exposure to a specific concentration of a biological agent or chemical. 

An antipolymerization agent such as hydroquinone may be added to the reaction mixture to inhibit the polymerization of the maleate or fumarate compound under the reaction conditions. This reaction is preferably carried out at a temperature within the range of 20°C to 150°C. This reaction is preferably carried out at atmospheric pressure. Reaction time of 16 to 24 hours have bean specified for this reaction by J.T. Cassaday. The reaction is preferably carried out in a solvent such as the low molecular weight aliphatic monohydric alcohols, ketones, aliphatic esters, aromatic hydrocarbons or trialkyl phosphates. 

The essence of a plant engineering contract will be that the plant actually performs to the criteria laid down in the design, and this must be established before a Practical Completion Certificate is even considered. Tests will need to be made to the plant, and then it will be commissioned by the contractor and left in a condition whereby it can be operated as specified. When the work within the contract is complete, a certificate should be issued by the client (or employer) to the contractor. The architect or consulting engineer acting as agent normally performs this duty. 

Water quality is important, not only from an environmental point of view but also in relation to the type of packing to be specified. Analysis of the circulating water is simple to obtain, but it is very seldom offered to the cooling tower designer. The quality, or lack of it, will determine the type of pack to be used, the selection of structural materials and whether the tower should be induced or forced draft, counterflow or crossflow. Water treatment, in the shape of chemicals to control pH and to act as counter-corrosion agents or as biocides, all has a bearing on tower selection. 

The available range of plastics is very wide with a variety of compositions and related properties within any one type description. Even when physical properties and formulation are specified, minor variations in trace additives, release agents, moulding cycles, etc. may have a considerable influence on corrosivity. Table 18.18 can therefore be considered only as a guide and even in this sense much more experimentation is needed to provide the full picture. In the present state of technology precise information is only likely to result from tests carried out on the material of interest various suitable test methods have been described in the literature ... 

Each agent is equipped with a user-specified personality - or internal value system defined by a six-component personality weight vector, m = wi,W2,. , wq),... 

In equation (q) only the fully ionised form of EDTA, i.e. the ion Y4 , has been taken into account, but at low pH values the species HY3, H2Y2, H3 Y and even undissociated H4Y may well be present in other words, only a part of the EDTA uncombined with metal may be present as Y4. Further, in equation (q) the metal ion M"+ is assumed to be uncomplexed, i.e. in aqueous solution it is simply present as the hydrated ion. If, however, the solution also contains substances other than EDTA which can complex with the metal ion, then the whole of this ion uncombined with EDTA may no longer be present as the simple hydrated ion. Thus, in practice, the stability of metal-EDTA complexes may be altered (a) by variation in pH and (b) by the presence of other complexing agents. The stability constant of the EDTA complex will then be different from the value recorded for a specified pH in pure aqueous solution the value recorded for the new conditions is termed the apparent or conditional stability constant. It is clearly necessary to examine the effect of these two factors in some detail. 

Which is the more powerful oxidizing agent under standard conditions, an acidified aqueous permanganate solution or an acidified aqueous dichromate solution Specify the cell for the spontaneous reaction of the two couples by writing a cell diagram that under standard conditions has a positive emf. Determine the standard emf of the cell and write the net ionic equation for the spontaneous cell reaction. 

Self-Test 12.9A Which metal, zinc or nickel, is the stronger reducing agent in aqueous solution under standard conditions Evaluate the standard emf of the appropriate cell, specify the cell with a cell diagram, and write the net ionic equation for the spontaneous reaction. 

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