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Tracer, uses

In situ control and calibration of flare and other gas metering systems is performed by gaseous tracers using the transit time method without affecting the normal production. Details about methodology are given in / /. [Pg.1054]

The method covers the full dynamic range of linear velocities from a few centimetres/second to over 100 meters/seconds with one and the same instrumental set-up. Only the amount of tracer used per injection is varied. [Pg.1055]

The hard point with respect to high and documented precision is to obtain an accurate figure of the sensitivity of the measuring position, relative to the tracer used. [Pg.1056]

It was discovered that the tracer used in problem 19-9 was subject to decay, and the measured concentrations could reflect both nonideal mixing and tracer decay. Therefore, a study of the... [Pg.492]

Cary EE, Wood RJ, Schwartz R (1990) Stable Mg isotopes as tracers using ICP-MS. J Micronutrient Anal 8(l) 13-22... [Pg.229]

The purpose of tracer experiments is to extract information about the system in a chemical reaction engineering context, it is the mixing within the system which is of interest, as represented by the system residence time distribution. Because flow mixing is an inherently linear process, the exact form of the RTD which is recovered from a tracer response experiment should be independent both of the amount of tracer used in the test and also of the particular functional form in which the tracer was... [Pg.230]

Miller et al., 1989 n = 6 children n = 3 n — 3 Age range 11-17 years 250 mg Ca as CCM enriched with tracer in form of chewable tablets Stable dual isotope tracers used to quantify CaAbs in urine and serum. Comparison of CCM chewable versus CCM swallowable supplements and CaCOa from data collected previously in same subjects Based on urinary excretion which correlated with serum data (r = 0.85) x SD% CaAbs from chewable CCM for molar ratio 6 2 3 (41.4 8.2%) > swallowable CCM for molar ratio 5 1 1 (39.5 10.6%) > CaCOa (26.7 7.8%) Chewable CCM > CaCOa (p =. 047) and swallowable CCM > CaCO (p =. 094)... [Pg.245]

The samples were analyzed for trace metals and sulfate as well as for three fractions of particulate organic matter (POM) using sequential extraction with cyclohexane (CYC), dichloromethane (DCM) and acetone (ACE). Factor analysis was used to identify the principal types of emission sources and select source tracers. Using the selected source tracers, models were developed of the form POM = a(V) + b(Pb) + - - -, where a and b are regression coefficients determined from ambient data adjusted to constant dispersion conditions. The models for CYC and ACE together, which constitute 90% of the POM, indicate that 40% (3.0 pg/m ) of the mass was associated with oil-burning, 19% (1.4 pg/m ) was from automotive and related sources and 15% (1.1 pg/m ) was associated with soil-like particles. [Pg.197]

Table 24.5 Characteristic Data of Chemical Tracers Used for the Gas Exchange Experiment Nondimensional Henry s Law Constant, Ki3/vi, Molecular Diffusion Coefficient in Air, Dia, and Water, Diw, Octanol-Water Partition Coefficient, Kiow, All valid for 4°C (Data from Cirpka et al., 1993)... Table 24.5 Characteristic Data of Chemical Tracers Used for the Gas Exchange Experiment Nondimensional Henry s Law Constant, Ki3/vi, Molecular Diffusion Coefficient in Air, Dia, and Water, Diw, Octanol-Water Partition Coefficient, Kiow, All valid for 4°C (Data from Cirpka et al., 1993)...
It is most convenient to express this distribution in a manner which is independent of the amount of tracer used. This is done by dividing the measured concentration by a base concentration, C . C is the concentration obtained by dissolving the total tracer rn ected by the available volume of the separator. E(t) = C/Co... [Pg.194]

The distribution Is made independent of time by dividing the experimental times by the mean residence time (t) for the entire system. E (0) = C7C. vs. 6 (where 9 s l/U) is the RTD in dimensionless units. Since this distribution is independent of the amount of tracer used and of the size and flow rate through the vessel, it can be used to compare flow regions under widely different conditions. [Pg.194]

Self-Diffusion Studies. Diffusion kinetics were determined, as previously described (14 17, 18), with the appropriate scaling down in sample size for enzyme experiments. The tracer used was 65Zn as supplied by the Radiochemical Center, Amersham, and was determined in solution by... [Pg.302]

There are certain analytical methods that can be applied to all fields of tracer use. Foremost among these is isotope dilution analysis (IDA). In this section we summarize the variants of this analytical method. [Pg.122]

In order to protect the flow stability from turbulence caused by the input signal, the properties of the tracer used should be as close as possible to those of the process particles. In the investigation carried out by the author of this book the process particles are yellow millets while purplish-red rape seeds are used as the tracer, the properties of which are very similar those of the millets. The properties of the process and the tracer particles are listed in Table 3.1. The concentration of the tracer is represented in terms of mass fraction, and is measured by manually separating the tracer from the process particles according to the difference in color and weighing the amount of tracer. This is laborious and time-consuming work, but it can yield reliable data. [Pg.79]

Canuel, E.A., Cloern, J.E., Ringelborg, D.B., Guckert, J.B., and Rau, G.H. (1995) Molecular and isotopic tracers used to examine sources or organic matter and its incorporation into food webs of San Francisco Bay. Limnol. Oceanogr. 40, 67-81. [Pg.558]

The radioactive tracer used was obtained by iodine 125-labeling of the conjugate of APS-314d and histamine, according to Hunter and Greenwood s method (1962). Stored at -30 °C the iodinated tracer was stable for at least 3 months without any loss of performance. It was diluted extemporaneously in assay buffer to obtain a solution containing 80 000 cpm per ml. [Pg.653]

While adequate Intestinal absorption Is clearly required to maintain zinc sufficiency, a number of different methods are presently used for Its measurement. Intestinal absorption has been measured by clinical balance studies, tracers (using both stable and radioactive Isotopes) and serum levels after Ingestion of pharmacologic doses of stable zinc compounds. Each can be useful, but each also has limitations and It Is Important to note that different methods. In reality, measure different aspects of absorption. While results are often reported as absorption, specific nomenclature has been developed to specify the results from each method of measurement(13,14). [Pg.68]

There is no known way in which drift of agricultural chemicals can be entirely eliminated, whether applied by ground or aircraft. Drift of tracers used in air pollution studies have been authenticated as far as 22 miles, and further distances could be expected, depending on the accuracy of the means for sensing tracer chemicals. Symptoms of 2,4-D drift have been noted on grapes 8 to 12 miles from the point of application and lawsuits in Texas and Washington have been based on greater drift distance. [Pg.53]

During an experiment in a multiphase system, the tracer should not be transferred from one phase to another phase. For example, a gaseous tracer used in a gas-liquid reactor should not be absorbed by liquid and a liquid tracer used to measure the liquid-phase RTD curve should not be volatile. Similarly, a solid tracer used to measure the RTD curve for the solid phase in a gas-liquid- solid slurry reactor should not dissolve in the liquid, etc. [Pg.62]

Experimental RTD data on any equipment can be obtained by imposing at the inlet a pulse, step or sinusoidal impulse and monitoring the response at the outlet. The tracer used must have physical properties such as density and viscosity similar to the test fluid food, and it should not in any marmer alter the properties of the test fluid food. The sinusoidal impulse and response require more care and sophisticated equipment than the pulse and the step inputs. The response to a pulse impulse is called a C-curve, while the response to a step change is called a F-curve. For a closed vessel, that is, in which material passes in and out by bulk flow (i.e., no difFusion at inlet and outlet) the Cand F functions are related as ... [Pg.439]

The most common and traditional tracers used in groundwater studies in the last few decades (e.g., H, C, and C1), as well as some relatively... [Pg.2720]

Hapten molecules are often coupled to carrier proteins (e.g., coating antigens used for the development of indirect competitive assays) or to enzjune labels (e.g., tracers used for detection in competitive assays). A protein has usually many different sites to which the hapten can be coupled and the chosen chemistry should obviously be one that leaves the active site as httle affected as possible. The number of haptens that can be coupled to one protein molecule (hapten density) by a particular chemistiy is essential for the final assay outcome [106-110]. [Pg.611]


See other pages where Tracer, uses is mentioned: [Pg.93]    [Pg.95]    [Pg.92]    [Pg.565]    [Pg.17]    [Pg.183]    [Pg.374]    [Pg.46]    [Pg.97]    [Pg.113]    [Pg.351]    [Pg.40]    [Pg.503]    [Pg.481]    [Pg.15]    [Pg.199]    [Pg.8]    [Pg.22]    [Pg.173]    [Pg.778]    [Pg.1094]    [Pg.350]    [Pg.3521]    [Pg.1356]   
See also in sourсe #XX -- [ Pg.33 , Pg.89 , Pg.103 , Pg.118 , Pg.157 , Pg.165 , Pg.229 , Pg.231 ]




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