Concentration volume percent

LOC limiting oxygen concentration (volume percent oxygen)... 

TABLE 23 1 Limiting Oxygen Concentrations (Volume Percent Oxygen Concentrations above Which Combustion Can Occur)... 

When mixing two liquids to form a solution, it is easier to measure their volumes than their masses. A volume/volume percent gives the volume of solute divided by the volume of solution, expressed as a percent. The volume/volume percent is also referred to as the volume percent concentration, volume percent, percent (v/v), or the percent by volume. You can see this type of concentration on a bottle of rubbing alcohol from a drugstore. (See Figure 8.17.)... 

Figure 1 Typical phase diagram for a polydisperse polymer in solution showing upper critical solution temperature behaviour (UCST) with schematic molecular interpretations (see text of Section 4.2 for detailed explanation). CPC denotes the cloud point curve and Sp the spinodal curve in the temperature-concentration (volume percent of polymer in the solution) plane at ambient pressure. T i and are points on the CPC and Sp curve respectively. The critical state is denoted by (< c ).

The units of concentration most frequently encountered in analytical chemistry are molarity, weight percent, volume percent, weight-to-volume percent, parts per million, and parts per billion. By recognizing the general definition of concentration given in equation 2.1, it is easy to convert between concentration units. 

A stock solution is prepared by weighing out an appropriate portion of a pure solid or by measuring out an appropriate volume of a pure liquid and diluting to a known volume. Exactly how this is done depends on the required concentration units. For example, to prepare a solution with a desired molarity you would weigh out an appropriate mass of the reagent, dissolve it in a portion of solvent, and bring to the desired volume. To prepare a solution where the solute s concentration is given as a volume percent, you would measure out an appropriate volume of solute and add sufficient solvent to obtain the desired total volume. 

Usually, free-radical initiators such as azo compounds or peroxides are used to initiate the polymerization of acrylic monomers. Photochemical (72—74) and radiation-initiated (75) polymerizations are also well known. At a constant temperature, the initial rate of the bulk or solution radical polymerization of acrylic monomers is first order with respect to monomer concentration and one-half order with respect to the initiator concentration. Rate data for polymerization of several common acrylic monomers initiated with 2,2 -azobisisobutyronittile (AIBN) [78-67-1] have been determined and are shown in Table 6. The table also includes heats of polymerization and volume percent shrinkage data. 

Flammable Limits Flammable limits, or the flammable range, are the upper and lower concentrations (in volume percent) which can just be ignited by an ignition source. Above the upper limit and below the lower hmit no ignition will occur. Data are normally reported at atmospheric pressure and at a specified temperature. Flammable hm-its may be reported for atmospheres other than air and at pressures other than atmospheric. 

The main advantage of absorption is its applicability to the control of pollutant gases present in large concentrations (several percent by volume). In these applications, removal efficiencies of 98°/ or greater can be achieved. The main disadvantage is inflexibility to achieve the best performance, the gas stream components are fixed once the column is designed, (see Table 13.1.3)... 

Where the oxidant concentration is continually monitored, a safety margin of at least 2 volume percent below the measured worst credible case LOG shall be maintained, unless the LOG is less than 5 volume percent, in which case, the equipment or piping shall be operated at no more than 60% of the LOG. 

Wliere the oxidant concentration is not continually monitored, the oxidant concentration shall be maintained at no more than 60% of the LOG or 40% of the LOG if the LOG is below 5 volume percent. If the oxidant concentration is not continually monitored the oxidant concentration shall be checked on a regularly scheduled basis. 

Fig. 12. Flow curves of poly(isobutylene), containing different concentrations of active filler (acetylene carbon black). Concentration (in volume percent) is indicated near the curves. A is the region of flow for stresses exceeding the yield stress B is the region directly adjacent to the yield stress...

A series of simulations were performed to study the effect of variables such as initiator concentration, initiator half-life and activation energy on the optimum temperature and optimum time. It was assumed that initially the polymerization mixture contained S volume percent monomer, the rest of the mixture being solvent and polymer formed earlier. It was required to reduce the monomer concentration from S volume percent to 0.S volume percent in the minimum possible time. The kinetic and tbeimodyamnic parameters used are similar to those of free radical polymerization of MMA. The parameter values are given in Appendix B. 

Figure 21 Chemiluminescence from polybutadiene the effect of oxygen concentration in a mixture with nitrogen, 130°C, total flow of gas 3.6 l/h, the numbers denote the volume percent of oxygen in the mixture with nitrogen.

We assume Pb++ during imbibition of the contaminated fluid is retarded by a factor of two (R = 2 see Section 21.1). This retardation requires the metal ion to be sorbed on the ferric surface to its aqueous concentration, 1 mmolal. Accounting for the concentrations of the two forms of sorbed lead, >(w)FeOPb+ and >(s)FeOPb+, after reaction with the contaminated fluid, this retardation is expected when the sorbing mineral Fe(OH)3 makes up 0.0085 volume percent of the aquifer. 

Limiting Oxygen Concentration and Inerting Table 6-2 Limiting Oxygen Concentrations (LOCs) (volume percent oxygen concentration above which combustion can occur)1 239... 

ISOC is the in-service oxygen concentration in volume % oxygen, z is the stoichiometric coefficient for oxygen given in Equation 6-9, and LFL is the fuel concentration at the lower flammability limit, in volume percent of fuel in air. 

Limiting Oxygen Concentration (LOC) Below the limiting oxygen concentration it is not possible to support combustion, independent of the fuel concentration. The LOC is expressed in units of volume percent of oxygen. The LOC is dependent on the pressure and temperature, and on the inert gas. Table 23-1 lists a number of LOCs, and it shows that the LOC changes if carbon dioxide is the inert gas instead of nitrogen. 

FIG. 26-9 Maximum pressure as a function of volume percent concentration for methane in air in a 20-L test sphere. The initial temperature and pressure are 25°C and 1 atm. The stoichiometric concentration is 9.51% methane. [C. V. Mashuga and D. A. Crowl, Application of the Flammability Diagram for Evaluation of Fire and Explosion Hazards of Flammable Vapors," Process Safety Progress, vol. 17, no. 3 copyright 1998 American Institute of Chemical Engineers (AlChE) and reproduced with permission.]... 

If the solute is ethyl alcohol and the solvent is water, then another concentration term is used, proof. The proof of an aqueous ethyl alcohol solution is twice the volume percent. A 45.0 volume % ethyl alcohol solution would be 90.0 proof. 

Poly(carboxyalkyl methyl siloxane) and octamethyl cyclo tetrasiloxane are mixed in a monomer ratio of 1 6, hexa methyl disiloxane is added to bring the polymerization degree of the ensuing silicone to about 60, and 6 volume percent of concentrated sulfuric acid are used as equilibration catalyst. 

Source Detected in distilled water-soluble fractions of 87 octane gasoline (24.0 mg/L), 94 octane gasoline (80.7 mg/L), Gasohol (32.3 mg/L), No. 2 fuel oil (0.50 mg/L), jet fuel A (0.23 mg/L), diesel fuel (0.28 mg/L), militaryjet fuel JP-4 (17.6 mg/L) (Potter, 1996), new motor oil (0.37-0.40 jg/L), and used motor oil (195-198 Jg/L) (Chen et ah, 1994). Diesel fuel obtained from a service station in Schlieren, Switzerland contained benzene at a concentration of 76 mg/L (Schluep et al, 2001). The average volume percent and estimated mole fraction in American Petroleum Institute PS-6 gasoline were 2.082 and 0.2969, respectively (Poulsen et al, 1992). Schauer et al. (1999) reported benzene in a diesel-powered medium-duty truck exhaust at an emission rate of 2,740 pg/km. 

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