Measuring variables, researchable

In order to perform the various tasks mentioned in Section 11.1.2, it is necessary to use one or several methods to gather information by NMR spectroscopy. Typically, chemical shift and coupling constant information, 2D-NMR measurements, variable temperature or pressure studies are used. If appropriate, specific examples of the particular topic as applied in homogeneous hydrogenation research are detailed below. 

Once a hypothesis is formulated, an experiment is conducted to test the hypothesis. Experimentation is what distinguishes chemistry, and other experimental science, from other disciplines. In simple experiments, the researcher designs the experiment to examine one independent variable and attempts to hold all other variables constant. Again, using the battery example, if the experiment was designed to test battery life in flashlights, then battery life would be the dependent variable. It would be im-portant to define in exact terms the variable battery life and exactly how it would be measured. The researcher would then attempt to control all other variables, except for one indepen-... 

In the last two decades, the researchers interest has been focused mainly on quantitative model-based methods, based on the concept of analytical or functional redundancy, which use a mathematical model of the process to obtain the estimates of a set of variables characterizing the behavior of the monitored system. The inconsistencies between estimated and measured variables provide a set of residuals,... 

Response to P2-agonists ean be expressed as the change in FEVi from baseline after either a single dose or 12 weeks of treatment. The American Thoracic Society defines an increase of more than 12% and at least 200 mL in FEVi as a significant bronchodilator response [7], An increase of 8% or less is considered within measurement variability. A 12% to 15% increase in FEVi is the common arbitrary threshold used in clinical research reports to separate patients who respond well to p2-agonists from those who respond poorly [13]. 

Analytical methods such as thin layer chromatography with flame ionization detection (TLC-FID) (Karlsen barter, 1991) are widely used in the oil industry. These solubdity based separation methods allow for the investigation of crude oil components based on polarity. However they can yield very different amounts of Saturates, Aromatics, Resins and Asphaltenes (SARA) depending on the nature of solvents used in the sepraration. At a p>anel discussion on standardization of petroleum fractions held at the 2009 Petrophase conference, a need to unify and improve the separation methods for asphaltenes and resins was expressed (Merino-Garcia et al., 2010). The diversity of operating definitions employed and measurement variability affect the ability of researchers to determine whether compound classes are present and to draw cross-comp>arisons among measurements from different... 

Three kinds of averages are defined from data that have been obtained for research questions. The mean is the point around which the values in the distribution balance it is the mathematical or arithmetic average. In order to calculate a mean, at least internal-level data exist. The median gives information about the value of the middle position in the distribntion. It is the point in the distribution of values at which 50 percent of the scores fall below and 50 percent of the scores fall above. In order to calculate a median, you must have at least an ordinally measured variable. Mode represents the most freqnent value in distribution. The mode is the simplest measure of averages and is, therefore, not viewed as an overly precise or informative measure of average. In addition, the mode is the only measure that is appropriate for nominal data. 

As any industrial facility, research reactors and critical facilities have many process variables to be measured. Table 1 is a typical list of process variables measured in research reactors. What follows is a discussion of the available sensors used to measure process variable, mainly temperature, pressure, level and flow. 

Other correlations based partially on theoretical considerations but made to fit existing data also exist (71—75). A number of researchers have also attempted to separate from a by measuring the latter, sometimes in terms of the wetted area (76—78). Finally, a number of correlations for the mass transfer coefficient itself exist. These ate based on a mote fundamental theory of mass transfer in packed columns (79—82). Although certain predictions were verified by experimental evidence, these models often cannot serve as design basis because the equations contain the interfacial area as an independent variable. 

To solve a flow problem or characterize a given fluid, an instmment must be carefully selected. Many commercial viscometers are available with a variety of geometries for wide viscosity ranges and shear rates (10,21,49). Rarely is it necessary to constmct an instmment. However, in choosing a commercial viscometer a number of criteria must be considered. Of great importance is the nature of the material to be tested, its viscosity, its elasticity, the temperature dependence of its viscosity, and other variables. The degree of accuracy and precision required, and whether the measurements are for quaUty control or research, must be considered. The viscometer must be matched to the materials and processes of interest otherwise, the results may be misleading. 

Valid emission factors for each source of pollution are the key to the emission inventory. It is not uncommon to find emission factors differing by 50%, depending on the researcher, variables at the time of emission measurement, etc. Since it is possible to reduce the estimating errors in the... 

In this test for transparent plastics, the loss of optical effects is measured when a specimen is exposed to the action of a special abrading wheel. In one type of test the amount of material lost by a specimen is determined when the specimen is exposed to falling abrasive particles or to the action of an abrasive belt. In another test, the loss of gloss due to the dropping of loose abrasive on the specimen is measured. The results produced by the different tests may be of value for research and development work when it is desired to improve a material with respect to one of the test methods. The variables that enter into tests of this type are... 

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