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Mass concentrations

In the case of solutions, the strength of the solution is usually not represented as a mass fraction, but as a mass concentration. Suppose a substance A has been dissolved in a solvent and the volume of the solution is V. The mass concentration is then represented by means of the formula  [Pg.44]


Measurements of mechanical and chemical parameters (time, dimensions, force, pressure, mass, concentration, relative molecular mass) + + + + + + -H -h... [Pg.916]

Polymer solutions are often characterized by their high viscosities compared to solutions of nonpolymeric solutes at similar mass concentrations. This is due to the mechanical entanglements formed between polymer chains. In fact, where entanglements dominate flow, the (zero-shear) viscosity of polymer melts and solutions varies with the 3.4 power of weight-average molecular weight. [Pg.435]

Although equation 35 is a simple expression, it tends to be confusing. In this equation the enthalpy difference appears as driving force in a mass-transfer expression. Enthalpy is not a potential, but rather an extensive thermodynamic function. In equation 35, it is used as enthalpy pet mole and is a kind of shorthand for a combination of temperature and mass concentration terms. [Pg.100]

In x-ray sedimentation, a collimated beam of x-rays permits particle concentration detection as a function of mass. The relationship between the fraction of x-rays transmitted and the mass concentration of particles of atomic weight >12 is expressed as in equation 13 ... [Pg.132]

Receptor models are powerful tools for source apportionment of particulates because a vast amount of particulate species characterization data have been collected at many sampling sites worldwide, and because many aerosol species are primary pollutants. Most of the information available is for elemental concentrations, eg, lead, nickel, and alurninum, although more recent measurements have provided data on concentrations of ionic species and carbonaceous compounds. At a sampling (or receptor) site, the aerosol mass concentration of each species i is... [Pg.379]

Aerosol Dynamics. Inclusion of a description of aerosol dynamics within air quaUty models is of primary importance because of the health effects associated with fine particles in the atmosphere, visibiUty deterioration, and the acid deposition problem. Aerosol dynamics differ markedly from gaseous pollutant dynamics in that particles come in a continuous distribution of sizes and can coagulate, evaporate, grow in size by condensation, be formed by nucleation, or be deposited by sedimentation. Furthermore, the species mass concentration alone does not fliUy characterize the aerosol. The particle size distribution, which changes as a function of time, and size-dependent composition determine the fate of particulate air pollutants and their... [Pg.382]

Flere C is the volume concentration of j-phase particles is the mass concentration of the analyte in the j-phase particles w is the x-ray fluorescence radiation yield t. is the mass absorption coefficient of the analyte for the primar y radiation d. is the j-phase particle effective size r fs... [Pg.113]

Suggested method characterized by relative standard deviation of 0.02-0.1 allows determination of water in organic solvents until 0.008 mass.%. Concentrations under mentioned above can not be detected by direct GC due to residual humidity of sorbent and parts of chromatographic equipment. [Pg.216]

The major purpose of ambient particulate sampling is to obtain mass concentration and chemical composition data, preferably as a function of particle diameter. This information is valuable for a variety of problems effects on human health, identification of particulate matter sources, understanding of atmospheric haze, and particle removal processes. [Pg.187]

The three major characteristics of particulate pollutants in the ambient atmosphere are total mass concentration, size distribution, and chemical composition. In the United States, the PM q concentration, particulate matter with an aerodynamic diameter <10 /nm, is the quantity measured for an air quality standard to protect human health from effects caused by inhalation of suspended particulate matter. As shown in Chapter 7, the size distribution of particulate pollutants is very important in understanding... [Pg.203]

Mass concentration units for ambient measurements are mass (/xg) per unit volume (m ). Size classification involves the use of specially designed inlet configurations, e.g., PMjq sampling. To determine mass concentration, all the particles are removed from a known volume of air and their total mass is measured. This removal is accomplished by two techniques, filtration and impaction, described in Chapter 13. Mass measurements are made by pre-and postweighing of filters or impaction surfaces. To account for the absorption of water vapor, the filters are generally equilibrated at standard conditions T = 20°C and 50% relative humidity). [Pg.204]

Other measurements important to visual air quality are pollutant related, i.e., the size distribution, mass concentration, and number concentration of airborne particles and their chemical composition. From the size distribution, the Mie theory of light scattering can be used to calculate the scattering coefficient (20). Table 14-2 summarizes the different types of visual monitoring methods (21). [Pg.209]

The most common monitoring of particulate matter is for light attenuation (opacity). Less frequently used methods exist for monitoring mass concentration, size distribution, and chemical composition. [Pg.550]

The mass concentration x can be related to the volume of adsorbed phase V by an assumed density of adsorbed phase r ... [Pg.307]

Attenuation of Provides short- or long-term TWA (e.g. up beta radiation to 8 hr, depending on model) of dust or Direct reading fume mass concentration. [Pg.355]

Airborne particulate matter, which includes dust, dirt, soot, smoke, and liquid droplets emitted into the air, is small enough to be suspended in the atmosphere. Airborne particulate matter may be a complex mixture of organic and inorganic substances. They can be characterized by their physical attributes, which influence their transport and deposition, and their chemical composition, which influences their effect on health. The physical attributes of airborne particulates include mass concentration and size distribution. Ambient levels of mass concentration are measured in micrograms per cubic meter (mg/m ) size attributes are usually measured in aerodynamic diameter. Particulate matter (PM) exceeding 2.5 microns (/i) in aerodynamic diameter is generally defined as coarse particles, while particles smaller than 2.5 mm (PMj,) are called fine particles. [Pg.15]

Hence, one can combine Eqs. (1.4)-<1.7) to develop the following expression for converting from ppm in the gas phase to mass concentration of species i ... [Pg.299]

Of particular importance is the case of wastewater with dilute pollutants at ambient temperature. In this case, one can use the following conversion from ppm to mass concentration ... [Pg.299]

Recently, much emphasis has been put on the harmful effects of small particles, i.e., particulate matter (PM), on human health. A number of standards have been established to characterize the PM fractions in the air and their effects on human health. A widely used PM standard in force in both Europe and the United States is based on the mass concentration of particles with a diameter of 10 gm or less (PMjo). However, recently the U.S. Environmental Protection Agency (EPA) proposed a new standard that is based on the aerodynamic diameter of 2.5 gm particles. This new standard emphasizes the significant impact of small particles on human health, especially on the respiratory and cardiovascular systems. 4 ... [Pg.251]

In the measurement of emission gas mass concentration at sources, a gas sample is extracted via an automatic isokinetic particulate-sampling instrument. The monitoring system generates a direct, real-time emission particulate mass... [Pg.1289]

TTie system can be used for continuous measurement of the mass concentration at a single point for up to 12 hours, for traverse measurements of stack particulate mass concentrations using sample probe extensions, with the mass transducer up to 6 m in the stack, or for intermittendy measuring particulate mass concentrations of emission gases for long-term readings (e.g.. 30-sec samples every 60 minutes. ... [Pg.1290]

In HOPC, a concentrated solution of polymer is injected. The concentration needs to be sufficiently higher than the overlap concentration c at which congestion of polymer chains occurs. The c is approximately equal to the reciprocal of the intrinsic viscosity of the polymer. In terms of mass concentration, c is quite low. For monodisperse polystyrene, c is given as (4)... [Pg.611]

For example, at MW = 4 X 10, c = 12 g/liter, and at MW = 5 X 10, c " = 62 g/liter. A polymer solution with concentration c > c is called a semidilute solution because mass concentration is low yet repulsive interactions between solutes are strong. Thermodynamics, viscoelasticity, and diffusion properties of semidilute polymer solutions have been studied extensively since the 1960s. [Pg.612]

The mass concentration (p.) of the i component (or species) in a homogeneous mixture is defined as the mass of that component present per unit volume of the... [Pg.327]

When the cell concentration is appreciable, the dilution rate must reach a specific rate (X / 0, D = ft). The cell mass concentration is defined in (6.8.1.13) as the dilution rate approaches zero the cell density is the product of yield and initial substrate concentration ... [Pg.157]

For an ideal gas, the total molar concentration Cj is constant at a given total pressure P and temperature T. This approximation holds quite well for real gases and vapours, except at high pressures. For a liquid however, CT may show considerable variations as the concentrations of the components change and, in practice, the total mass concentration (density p of the mixture) is much more nearly constant. Thus for a mixture of ethanol and water for example, the mass density will range from about 790 to 1000 kg/m3 whereas the molar density will range from about 17 to 56 kmol/m3. For this reason the diffusion equations are frequently written in the form of a mass flux JA (mass/area x time) and the concentration gradients in terms of mass concentrations, such as cA. [Pg.596]


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Aerosol characterization mass concentration

Aerosol mass concentration

Analytical techniques mass concentration

Atom concentrations, mass spectrometry

Carrier Concentration and Mobility. Effective Mass

Cell mass concentration

Concentrated solutions mass percent

Concentration Polarization or Mass Transport Losses

Concentration and Molar Mass

Concentration by mass

Concentration expression mass/volume

Concentration mass fraction

Concentration mass percent

Concentration mass volume

Concentration mass/volume percent

Concentration parts by mass

Concentration percent by mass

Concentration polarization mass transfer limitation

Concentration profiles and heights of mass transfer columns

Concentration surface mass

Concentration units mass fraction

Concentration units percent by mass

Concentrations, toluene mass distribution

ESI-MS Concentration or Mass Flow Dependent

Eddies mass transfer, concentration gradient

Elemental mass concentration

Enzyme Mass Concentration

Experimental methods mass concentration

Liquid chromatography tandem mass protein concentration

Mass Action and Concentration Dependence of Chemical Potential

Mass Fraction and Concentration

Mass Transfer Coefficient and Wall Concentration

Mass Transfer or Concentration Loss

Mass Transport or Concentration Losses

Mass and Charge Transport in the Presence of Concentration Gradients

Mass balance concentrations

Mass balance concentrations ratios

Mass balances for in gas concentration

Mass balances organic pollutants concentrated

Mass concentration calculation

Mass concentration determining

Mass concentration profiles

Mass concentration transfer coefficient

Mass convection concentration

Mass convection concentration boundary layer

Mass density concentration

Mass spectrometry measuring concentration rang

Mass spectroscopy analyte concentrations

Mass transfer between phases concentration profiles

Mass transfer concentrated systems

Mass transfer concentration

Mass transfer concentration profiles

Mass transfer driving concentration difference

Mass transfer internal concentration profiles

Mass transfer molar concentration

Mass transfer rate volatile component concentration

Mass transport concentration profile

Mass transport total metal concentration

Mass- and Volume-Based Concentration

Mass- and Volume-Based Concentration Units

Model solute mass recoveries, concentrated

Particle Concentration and Mass Flux Measurements by PDA

Particle mass concentration, flocculation

Particle removal mass concentration

Percentage concentration by mass

Polymer mass concentration

Qualitative Analysis of Concentration Profiles and Mass Transfer

Reaction mass concentration

Skill 16.4 Solving problems involving concentrations of solutions (e.g., molarity, molality, percent by mass percentage)

Solute mass concentration

Spectroscopy concentration mass

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