Safe dilution volume

Solvent Threshold limit value Safe dilution volume... 

The radioactivity of important radionuclides in spent fuel as a function of time after the fuel is removed from a reactor is indicated in Table 13.7. Figures 13.18 and 13.19 describe the water dilution volumes for the radionuclides in spent fuel and reprocessed waste as a function of time. (The water dilution volume is the volume of water needed to dilute the amount of a given isotope in the waste to a concentration safe for ordinary use.) Ordinant values in Figs. 13.18 and 13.19 can also be viewed as a measure of the radioactivities of the isotopes as a function of time. For both spent fuel and reprocessed waste, the chief source of radioactivity for the first 10 to 100 y is the fission products "Sr and " Cs. Thereafter, up to about 10,000 y. Am and (briefly) Pu isotopes are the dominant... 

Freshly opened bottles of these reagents are generally of the concentrations indicated in the table. This may not be true of bottles long opened and this is especially true of ammonium hydroxide, which rapidly loses its strength. In preparing volumetric solutions, it is well to be on the safe side and take a little more than the calculated volume of the concentrated reagent, since it is much easier to dilute a concentrated solution than to strengthen one that is too weak. 

SpiHs can also be diluted with large volumes of water. Care should be taken, however, because chlorosulfuric acid reacts violentiy with water Hberating heat, hydrochloric acid, and sulfuric acid mists and steam. The water should be appHed from a safe distance upwind of the spiH using a fog no22le. Remaining traces of acid should be neutrali2ed with soda ash, caustic soda, or lime before disposal. 

Asphyxiation is another invisible hazard. If the oxygen level in a room decreases below a certain level you may become unconscious and die. In general, big laboratories are better than small labs because the natural volume of the room will help to dilute these effects. Likewise, an efficiently air conditioned room will change the air in the room fairly rapidly and this will also help keep oxygen levels up. If your NMR magnet is in a small room, it may be necessary to install oxygen depletion sensors. These will alert you should the oxygen level fall below a safe value. 

However, because both acids and bases are used in cleaning, it may be possible to store these chemicals in a stirred buffer tank to allow the solution to neutralise. This solution may then may be slowly added to the concentrate waste to dilute it and allow for a safe disposal (Mauguin and Corsin 2005). Note that the volume of this discharge is much lower than both the concentrate and filter backwash discharges. 

By the definition of T (f), is the volume of the cavity in which the particular solvent is replaced by the solute. Therefore Vp depends on the particular solvent chosen for the SANS-experiment and also on concentration. For the dilute regime under consideration here the latter dependence can safely be dismissed. 

Often pesticide wastes, which require special disposal facilities, are in a dilute form and result from rinsates from containers, spray tanks, and equipment wash water. These may originate from the small applicator or large commercial operator. Such wastes should be sprayed on an area for which they are approved or placed in a safe disposal facility. Occasionally, fairly large volumes of recommended concentration dilute mixtures resulting from livestock dipping operations, overestimating the amount needed for a spray operation, etc., must be discarded. 

Instruct others to maintain a safe distance. Wear face shield and goggles, laboratory coat, and butyl rubber gloves. Cover the spill with dry sand. Scoop the resulting mixture into a pail and, in the fume hood, slowly add to an excess of butanol (10 mol l mol, 24 mL/g hydride). When the reaction is complete, dilute with water, and allow the solids to settle. Flush the solution down the drain with at least 50 times its volume of water. The solid residue may be discarded with normal refuse.16... 

Potassium metal. Instruct others to maintain a safe distance. Wear eye protection, laboratory coat, and nitrile rubber gloves. Cover with dry sodium carbonate or calcium carbonate, scoop into a dry plastic pail, and transport to fume hood.3 Behind a shield, add a little at a time to a large excess of dry lerl butyl alcohol. Allow it to stand for 24 hours, and then wash into the drain, diluting greatly with at least 50 times its volume of water.4... 

In addition, explosion protection by using inert gases can be derived from this rule in the presence of combustible substances, the oxygen content of the surrounding atmosphere will be reduced to a safe level - some per cent by volume - by dilution with an inert gas such as nitrogen or carbon dioxide. 

For ingestion the SITP is defined as the volume of water required to dilute a material to a concentration that would be safe to drink if a population were to use the mixture as its sole source of water. The derivation of SITP values is as follows ... 

The configuration of most ion exchange plants involve one or several fixed resin beds contained in cylindrical pressure vessels interconnected by pipework. Valves control and direct pumped or gravity fed liquid flows in a strictly controlled sequence, and safely designed regenerant measuring plus dilution systems are required to handle resin regeneration chemicals. Finally, instrumentation is required to monitor liquid levels, flows, pressures, volumes, and product quality. 

An air compressor provides dilution air for the ammonia to aid injection and distribution. Air to ammonia ratio of approximately 20/1 is used to stay safely below the 15% LET, for NH3, and to provide enough volume for good NH3 distribution. 

For example, EPA has developed safe standards for the toxicity of many emissions. Relative safety can then he defined in terms of safe emission levels of each. A method of accounting known as the critical volume method is used to estimate the volume of ambient air or water that would he required to dilute contaminants to acceptable safety standards. Athena EIE calculates and reports indices based on the worst offender—that is, the substance requiring the largest volume of air and water to achieve dilution to acceptable levels. 4 The hypothesis is that the same volume of air or water can contain a number of pollutants. 

Ideally, a solution of a mixture of components applied to a chromatographic column in a small volume would be totally separated and each solute eluted in the same small volume. However, as discussed previously, solute bands broaden as they move down a chromatographic column. For a column of length L we have seen that the broadening increases proportionally to /L whereas the separation of band centres is directionally proportional to L. Consequently, a sufficiently long column will always give a required separation, but in practice the solute will either be too dilute to detect, or the pressure needed to cause flow will be too high to permit safe operation of the equipment. Such problems can be overcome by a careful choice of stationary and mobile phases such that the solutes are selectively retained. The resolution (i s) of two components is a measure of how well they are separated (Fig. 2.5) and is defined by the equation ... 

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