Performance of a measurement

The special features and properties of the individual reagent carriers are entered on the method sheets reproduced at the end. 

The instrument must be calibrated before performing measurements of reagent samples with reagent carriers if 

The following are considered optimum ambient conditions for the Seralyzer system room temperature, +15 to +32°C relative atmospheric humidity, 15 to 85%. 

The reagent carrier should remain in the instrument for at least 2 minutes, since the moisture must distribute uniformly within the hollow sphere to ensure that the inside area is well moisturised. The plug-in unit is then removed and the reagent carrier is discarded. This hydratisation of the internal area of the hollow sphere is imperative no calibrations or measurements should be performed before this has been accomplished. If this precaution is disregarded, measurements will be imprecise and incorrect. 

Too high concentrations (activities) are indicated by an error report or by a maximal value. The samples must then be diluted further and the analysis repeated. Pressing the DIL button causes automatic multiplication in the instrument, but the prescribed dilution must always be employed by the user. Samples of very low concentration (activity) will also cause an error report. These samples must then be measured by a different method. 

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The performance of a measuring instrument can be expressed in several ways. The precision or accuracy describes the instrument performance in a general and qualitative sense. Thus, these expressions cannot be characterized using numbers. 

ISO Guide 33 (1998) deals with other uses of RMs. It elaborates on various uses of RMs, excluding calibration, which is the subject of ISO Guide 32. In most cases, RMs are used as a quality control measure, i.e. to assess the performance of a measurement method. Most matrix RMs are produced with this purpose in mind. Other purposes of RMs are the maintenance of conventional scales, such as the octane number and the pH scale. ISO Guide 33 provides guidance on the proper use of RMs, and therefore it is together with ISO Guide 32 the most important document for users of CRMs. 

This example has been chosen to show that it is possible to calculate the optimal performance of a measurement protocol in conditions close to those in the field. For a set value of 6 (actually the unknown parameter) it is then possible to seek the value of x that minimizes CRB for a set number n. This optimization is often impossible to carry out analytically when n>2 and/or when matrix I has a complex... 

Performance of a measure regarding a particular accident constellation. 

In the case of a plate column the performance of a real plate is related to the performance of a theoretical one by the plate efficiency. In the case of a packed column the height equivalent to a theoretical plate HETP) gives a measure of the contacting efficiency of the packing. 

Fig. 7 shows the torque necessary to obtain the specified body force under construction conditions and in tbe state when removed from the bridge. It can well be seen that the change of the friction coefficient causes a very big scattering, and the necessary torque is much bigger than specified. The distribution of the results of a measurement performed on 1,127 bolts is presented in Figure 8. An average of 80% of nominal body force was found by the new method. The traditional method found the nuts could be swivelled much further than specified on 42 bolts, these bolts were found to have 40 - 60 % body force by the new method. 

Two usehil measures of the performance of a sound-isolating constmction are sound transmission loss (TL) and noise reduction (AIR). Sound transmission loss is defined as follows, where IH is the incident sound power (Watts) on the source side of the specimen, and W is the transmitted sound power on the receiving side (7). 

There are important figures of merit (5) that describe the performance of a photodetector. These are responsivity, noise, noise equivalent power, detectivity, and response time (2,6). However, there are several related parameters of measurement, eg, temperature of operation, bias power, spectral response, background photon flux, noise spectra, impedance, and linearity. Operational concerns include detector-element size, uniformity of response, array density, reflabiUty, cooling time, radiation tolerance, vibration and shock resistance, shelf life, availabiUty of arrays, and cost. 

An important property of a pigment is its ability to maintain its color when exposed to light, weather, heat, and chemicals. This property is seldom measured for pigments alone. Rather it is determined for the dispersion of a pigment in a desired medium, eg, paints or plastics, and in many cases it is compared to the performance of a standard pigment. The observed changes are the result of complex pigment and media reactions and their possible interactions. In aH evaluations, time of exposure plays a role. 

Much of the experimental work in chemistry deals with predicting or inferring properties of objects from measurements that are only indirectly related to the properties. For example, spectroscopic methods do not provide a measure of molecular stmcture directly, but, rather, indirecdy as a result of the effect of the relative location of atoms on the electronic environment in the molecule. That is, stmctural information is inferred from frequency shifts, band intensities, and fine stmcture. Many other types of properties are also studied by this indirect observation, eg, reactivity, elasticity, and permeabiHty, for which a priori theoretical models are unknown, imperfect, or too compHcated for practical use. Also, it is often desirable to predict a property even though that property is actually measurable. Examples are predicting the performance of a mechanical part by means of nondestmctive testing (qv) methods and predicting the biological activity of a pharmaceutical before it is synthesized. 

One measure of the performance of a control system is the variance of the controlled variable from the target. Both improving the control svstem and reducing the disturbances will lead to a lower variance in the controlled variable. 

Time-Delay Compensation Time delays are a common occurrence in the process industries because of the presence of recycle loops, fluid-flow distance lags, and dead time in composition measurements resulting from use of chromatographic analysis. The presence of a time delay in a process severely hmits the performance of a conventional PID control system, reducing the stability margin of the closed-loop control system. Consequently, the controller gain must be reduced below that which could be used for a process without delay. Thus, the response of the closed-loop system will be sluggish compared to that of the system with no time delay. 

Principles The performance of a real refrigerator is measured by the coefficient of performance, COP, defined as... 

When testing to estabhsh the thermodynamic performance of a steam turbine, the ASME Performance Test Code 6 should be followed as closely as possible. The effec t of deviations from code procedure should be carefully evaluated. The flow measurement is particularly critical, and Performance Test Code 19 gives details of flow nozzles and orifices. The test requirements should be carefully studied when the piping is designed to ensure that a meaningful test can be conducted. 

The initial direction of transport of pollutants from their source is determined by the wind direction at the source. Air pollutant concentrations from point sources are probably more sensitive to wind direction than any other parameter. If the wind is blowing directly toward a receptor (a location receiving transported pollutants), a shift in direction of as little as 5° (the approximate accuracy of a wind direction measurement) causes concentrations at the receptor to drop about 10% under unstable conditions, about 50% under neutral conditions, and about 90% under stable conditions. The direction of plume transport is very important in source impact assessment where there are sensitive receptors or two or more sources and in trying to assess the performance of a model through comparison of measured air quality with model estimates. 

Winterbone, D.E., Nikpour, B., and Alexander, G.L., 1990, Measurement of the Performance of a Radial Inflow Turbine in Conditional Steady and Unsteady Flow, IMechE, Paper No. 0405/015. 

Similar to supply inlets, no measurements exist for evaluating the inlets specific influence on contaminant concentration. The available measurements for the combinations are the same as for exhaust hoods, i.e., capture efficiencies and similar measures. Sometimes the performance of a combined system can be approximated from the performance of the incoming supply inlet and exhaust hood. 

The evaluation methods could be direct, e.g., measuring a containment index, or indirect, e.g., measuring pressure loss or velocity distribution. The direct methods are used to measure the performance of a hood or an inlet during periodic preventive maintenance. Indirect methods are used for verifying or checking on a daily basis (routine checks). How often each method is used depends on the availability of instrumentation and qualified personnel, since direct measurement of a hood s performance can be both expensive and difficult. On the other hand, indirect methods are usually easier to use and can sometimes include inexpensive, continuously monitoring instruments (pressure gauges or velocity indicators). 

Response A reaction of a living organism caused by a pollutant. Also, the reaction time of a measuring instrument or control device to perform an action. 

But for power station applications, the thermal efficiency is not the only measure of the performance of a plant. While a new type of plant may involve some reduction in running costs due to improved thermal efficiency, it may also involve additional capital costs. The cost of electricity produced is the crucial criterion within the overall economics, and this depends not only on the thermal efficiency and capital costs, but also on the price of fuel, operational and maintenance costs, and the taxes imposed. Yet another factor, which has recently become important, is the production by gas turbine plants of greenhouse gases (mainly carbon dioxide) which contribute to global warming. Many countries are now considering the imposition of a special tax on the amount of CO2 produced by a power plant, and this may adversely affect the economics. So consideration of a new plant in future will involve not only the factors listed above but also the amount of CO2 produced per unit of electricity together with the extra taxes that may have to be paid. 

It is difficult to decide what should serve as adequate column quality parameters for describing the performance of a set of GPC columns. The two most common measures are plate count and resolution. While both of these can be useful for monitoring the performance of a column set over time, it is not generally possible to a priori specify the performance needed for a specific analysis. This will depend on the nature of the polymer itself, as well as the other matrix components. 

Efficiency is a practical measure of the performance of a converter efficiency is equal to the desired form of energy divided by the total energy converted. If the light converted 100 joules of energy into 10... 

In practice, the only positive way to evaluate performance of a unit is to install it in the compressor system and observe its operation relative to noticeable system vibration, compressor performance, and measured frequency information. More recent (circa 1996) developments have continued to use the earlier analog techniques,and digital computer programs now allow an evaluation of the system prior to fab-... 

Generally, failure is described in terms of time to failure. Although in certain instances a more relevant measure for exposure before failure is necessary such as cycles to failure or miles to failure. It should also be noted that the word failure is used in a general sense to indicate any specific deterioration in performance of a unit. Additionally, if units are put into service at different times, the time in use for each unit is figured from its starting time. 

The comparison of more than two means is a situation that often arises in analytical chemistry. It may be useful, for example, to compare (a) the mean results obtained from different spectrophotometers all using the same analytical sample (b) the performance of a number of analysts using the same titration method. In the latter example assume that three analysts, using the same solutions, each perform four replicate titrations. In this case there are two possible sources of error (a) the random error associated with replicate measurements and (b) the variation that may arise between the individual analysts. These variations may be calculated and their effects estimated by a statistical method known as the Analysis of Variance (ANOVA), where the... 

This requirement also makes good sense. A calibration is nothing more than a mathematical model that relates the behavior of the measureable data to the behavior of that which we wish to predict. We construct a calibration by finding the best representation of the fit between the measured data and the predicted parameters. It is not surprising that the performance of a calibration can deteriorate rapidly if we use the calibration to extrapolate predictions for... 

One of the earliest steps in product design is to establish the configuration of the product that will form the basis on which a suitable material is selected to meet performance requirements. During this phase certain design features have to be kept in mind to avoid problems such as reduction of properties. Such features are called detractors or constraints. Most of them are responsible for the unwanted internal stresses that can reduce the available stress level for load bearing purposes. Other features may be classified as precautionary measures that may influence the favorable performance of a product if they are properly incorporated. 

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