Measurement, methodology

It is noteworthy that several studies exhibit contradictory results for both the mechanical and thermal characteristics of the flow. This is generally due to differences in the many parameters that characterize these studies such as the geometry, shape and surface roughness of the channels, the fluid, the boundary conditions and the measuring methodology itself. These discrepancies indicate the need for extension of the experimental base to provide the necessary background to the theoretical model. 

Measurement of exposure can be made by determining levels of toxic chemicals in human serum or tissue if the chemicals of concern persist in tissue or if the exposure is recent. For most situations, neither of these conditions is met. As a result, most assessments of exposure depend primarily on chemical measurements in environmental media coupled with semi-quantitative assessments of environmental pathways. However, when measurements in human tissue are possible, valuable exposure information can be obtained, subject to the same limitations cited above for environmental measurement methodology. Interpretation of tissue concentration data is dependent on knowledge of the absorption, excretion, metabolism, and tissue specificity characteristics for the chemical under study. The toxic hazard posed by a particular chemical will depend critically upon the concentration achieved at particular target organ sites. This, in turn, depends upon rates of absorption, transport, and metabolic alteration. Metabolic alterations can involve either partial inactivation of toxic material or conversion to chemicals with increased or differing toxic properties. 

This measurement methodology and data analysis is general and can be extended to other porous media. The results from MRI moisture profiles can also be used to measure moisture diffusivity that enable moisture transport models to be developed for a wide range of materials. 

In a large survey of radon transport phenomena (Collfe et al., 1981) several exhalation measurement methodologies were reviewed. One of the laboratory techniques in that review, perhaps the most common one for exhalation measurements of small porous samples, will be scrutinized in this contribution. I am referring to the closed-can accumulation method, which means that the sample to be investigated is enclosed in a can and the exhalation of radon is determined from the radon growth in the air inside the can. 

Pikal, M. J., Shah, S. The collaps temperature in freeze-drying Dependence on measurement methodology and rate of water removal from the glassy phase. International Journal of Pharmaceutics 62, p. 165-186, 1990... 

Two important, but often under emphasized, aspects of measuring c/w values and isotherms in foods are accuracy and repeatability. Variation in and isotherm values can be due to inherent variation in biological materials, as well as differences in measurement methods, protocols, and equipment employed. Wolf et al. (1985) presented the results of a COST 90 Project on the standardization of saturated salt solution isotherm measurement methodology and Lewicki and Pomaranska-Lazuka (2003) discussed errors in the static desiccator method. 

These parameters need to be considered for reactions that go towards the intended completion as well as for possible upsets (see section C). Measuring methodologies for determining characteristic material property values (Stoffkenngrofcen), e.g., differential thermal analysis ("DTA"), calorimetry, and adiabatic experiments, and their possible use and applications are given in the literature /1, 2, 3, 41. 

The maximum permissible temperature ("TeXo") is the maximum permissible temperature at which a material or reaction mixture can just be handled without risk. This temperature needs to be defined with due consideration for the process parameters and the measuring methodology that was used to determine the material characteristics. For example, the maximum permissible temperature in a continuous process can be set at a higher level than in a batch process. This is due to the fact that in a continuous process materials are only briefly exposed to high temperatures while in a batch process materials can be exposed to high temperatures for extended periods of time. 

In what follows, we wish to describe the most important technical aspects of FFC NMR relaxometry, including both the required special hardware (magnet, power supply, etc.) and the measurement methodology (data acquisition sequences and, to some extent, the subsequent data evaluation). Naturally, the description is based primarily on our own experience which has not yet been described in detail elsewhere. 

Only a small subset of method-specific questions are shown in Table 2.3 because of the breadth of chemometric and measurement methodology. Understanding the information in Chapters 3-5 will help generate chemometric-related questions. The decision trees in these chapters can also help determine appropriate method(s) for a given situation. In time, your experience will also become a valuable resource. 

For the development of the measurement methodology, it is anticipated that the same mechanism of O2 A ) generation occurs under both one- and two-photon excitation. This expectation is reasonable due to the very short duration of the femtosecond laser pulse used for two-photon excitation. Thus,... 

Pikal, M.J., Shah, S. The collapse temperature in freeze-drying dependence on measurement methodology and rate of water removal from the glassy phase. Int. J. Pharm. 62,165-186,1990 Thijssen, H.A.C., Rulkens, W.H. Effect of freezing rate on rate of sublimation and flavour retention in freeze-drying, pp. 99-114. International Institute of Refrigeration (HR) (Comm. X, Lausanne), 1969... 

In comparing simulated and experimentally measured transport parameters one has to be aware that experimental data in the literature depending, for example, on sample preparation conditions and the chosen measurement methodology can show a considerable scatter, often reaching a factor of two or even more. It is, for example well-known that polyimides often contain residual solvent filling a part of the free volume and thus leading to systematically lower S and D values from experiments than from simulations [34]. 

Direct measurement of dietary zinc availability in humans requires development of the stable isotope tracer methodology. Several aspects of this integrated methodology are considered and briefly discussed. These are analytical isotopic measurement methodology, consequences of the finite precision of isotopic measurements, validation of in vivo measurements, and several aspects of biological labeling of human foods. It is shown that Radiochemical Neutron Activation Analysis provides a suitable method for accurate measurement of the stable isotopes Zn,... 

Consequences of Finite Precision of Measurement. The available measurement methodology indicates that overall isotopic... 

The most recent US-based measurement methodologies are based on laser sources and are of two general types, namely (a) all-laser approaches, where both US generation and detection are laser based and (b) half-laser approaches, where laser light is used either for generation or detection of US, but not both. 

Therefore a (semi-) continuous measuring methodology, like MS was considered. Trace analysis by MS via a membrane separator was known (2), but the decay times of the signal precluded breath-by-breath analysis. 

Temperature sensors for providing closed-loop feedback for APFC are being developed by Stanford University for the measurement of combustion species and temperature. Laser-diode sensors offer nonintrusive measurements of the combustion exit plane temperature pattern. A detailed description of the sensor measurement methodology can be found in the literature [1, 2]. There is... 

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