Measures continuous

Table 3-2 Survey of measuring instmments for corrosion protection measurements (continued)...

Following production launch, process capability and performance should be measured continually in order to demonstrate that your processes remain capable and the capability index continues to rise. Appropriate action should be taken on characteristics that are either unstable or non-capable. Action plans should be implemented to contain process output and continually improve performance. 

CCPS has developed guidelines for the measurement of PSM performance that provide useful ideas on measurement. Their approach for developing performance measures integrates Quality Management with a well-tested methodology for developing measures based on mathematical algorithms derived from expert assessment of system performance. The purpose was to identify well-defined, measurable, and practical indicators of performance that are updated on a schedule which makes the performance measure continuously useful. To date, measures have been developed for... 

End-of-pipe measures continue to be vitally important. The largest PSM and ESH management costs are accident and incident related. If you reduce the costs of managing PSM and ESH, yet accident and incident rates rise beyond any normal statistical variation, the new system is costing the company more. Near misses are a leading indicator for accidents and incidents and should not be neglected. 

Fig. 9.6 Method of preventing corrosion by premature condensation of acidic vapours. pH measured continuously at point X automatically controls flow of sodium hydroxide...

The chromium in the substance is converted into chromate or dichromate by any of the usual methods. A platinum indicator electrode and a saturated calomel electrode are used. Place a known volume of the dichromate solution in the titration beaker, add 10 mL of 10 per cent sulphuric acid or hydrochloric acid per 100 mL of the final volume of the solution and also 2.5 mL of 10 per cent phosphorus) V) acid. Insert the electrodes, stir, and after adding 1 mL of a standard ammonium iron)II) sulphate solution, the e.m.f. is measured. Continue to add the iron solution, reading the e.m.f. after each addition, then plot the titration curve and determine the end point. 

One of the most informative properties of any material is their mechanical behavior specifically the determination of its stress-strain curve in tension (ASTM D 638). This is usually accomplished in a testing machine by measuring continuously the elongation (strain) in a test sample as it is stretched by an... 

Equation (4.3) is exactly true only if q is an infinitesimal amount of heat, causing an infinitesimal temperature rise, dr. However, unless the heat capacity is increasing rapidly and nonlinearly with temperature, equation (4.3) gives an accurate value for Cp at the average temperature of the measurement Continued addition of heat gives the heat capacity as a function of temperature. The results of such measurements for glucose are shown in Figure 4.1.2... 

In Mexico City, several air quality parameters are measured continuously by an Automated Monitoring Network operated by the Under Secretariat of Ecology. Carbon monoxide, particulate matter, sulfur dioxide, nitrogen oxide, and ozone are the contaminants exceeding Air Quality Standards. Emissions produced by 2.7 million vehicles and 35,000 commercial and industrial outfits are not easily dispersed in a Valley located at 2240 m and surrounded by two mountain chains which hinder air circulation. An Integral Program, recently established to alleviate pollution, is briefly described. 

Seligson s group (95) has published a similar turbidimetric procedure but used nephelometry to measure continuously the effect of lipase on the light scattering of an olive oil emulsion. The instrumentation and approach is the same as that described above for the nephelometric determination of amylase. The method according to the authors is fast and precise with good specificity and sensitivity. The short time required for analysis makes it suitable for emergency use. The technical simplicity permits this method to be easily automated, and it appears to be the lipase method of choice. 

The radon in the air i/as measured continuously by electroprecipitation of the positively charged Po-218 ions in an electric field (10 kV) on a surface barrier detector (Porstendorfer, et al., 1980). For this purpose the air i/as dried, filtered and sucked into an aluminium sphere ( 2 1) with a flowrate of 0.5 lmin-1. The counts due to Po-218 and Po-214 were proportional to the radon activity concentration. Their disintegrations were directly detected by alpha spectroscopy with an energy resolution of about 80 keV. The monitor could detect down to 5 Bq m 3 with a two hour counting time and 30 % statistical accuracy. 

Figure 4b shows unmistakably a growth mode occurring at SO2 concentration 10-20 ppm injected into the mainstream at the point where the CN were injected (Droullard et al, 1984). The condensation nuclei level, as measured continuously by a TSI counter, increased to about 4 X 105 cm 3 level during the time when measurements in figure 3b were taken. Note that at size 4.2nm the counter efficiency is only 8% (Agarwal and Sem, 1980). The value 4 X 105 is corrected for that. 

The physical property and the sample temperature should be measured continuously. 

To use the OFRR as a biosensing device, the optical resonant mode is excited and the resonant frequency is measured continuously in real time. The conceptual measurement setup is illustrated in Fig. 14.3. Laser light from a distributed feedback (DFB) laser is delivered to the OFRR using fiber optic cable. One method that has been used to excite the resonant modes is to place a tapered fiber optic cable with a diameter less than 4 pm in contact with the OFRR. The evanescent field of the tapered fiber overlaps with the evanescent field outside of the capillary wall, which enables mode coupling between the two media24. 

When using a single-beam spectrometer, I0 is measured when a reagent blank is used to zero the absorbance scale. The value of I is then measured when the sample is inserted into the spectrometer. On the other hand, when using a double-beam instrument both the reagent blank, 70, and the sample, I, are measured continuously and the appropriate ratio is determined electronically. 

Groups of ten male Crl CD rats were exposed to HCN in polymethymethacrylate exposure chambers under flow-through conditions (E.I. du Pont de Nemours 1981). The chamber atmosphere was measured continuously by infrared spectrophotometry measurements were validated by gas chromatography. The experiment was performed in duplicate with one set of animals exposed head-only to the test gas while the other set was allowed free movement inside the exposure chamber. Free-moving rats inhaled concentrations of 273 to 508 ppm for 5 min, 110 to 403 ppm for 15 min, 128 to 306 ppm for 30 min, or 76 to 222 ppm for 60 min. The postexposure observation period was 14 d, during which body weights were monitored. 

The traditional acute, subchronic, and chronic toxicity studies performed in rodents and other species also can be considered to constitute multiple endpoint screens. Although the numerically measured continuous variables (body weight, food consumption, hematology values) generally can be statistically evaluated individually by traditional means, the same concerns of loss of information present in the interrelationship of such variables apply. Generally, traditional multivariate methods are not available, efficient, sensitive, or practical (Young, 1985). 

Optical fiber detectors (OFD) are devices that measure electromagnetic radiation transmitted through optical fibers to produce a quantitative signal in response to the chemical or biochemical recognition of a specific analyte. Ideally, an OFD should produce a specific and accurate measurement, continuously and reversibly, of the presence of a particular molecular species in a given sample medium. Additionally, OFD should pro vide maximum sensitivity and minimal interferences fromsuperfluous ions or molecules to obtain low detection limits. Other attractive features include the miniaturization of the fiber s tip to accommodate single-cell analysis and portable instrumentation to allow in situ analysis. 

A potentiostat is relatively expensive, especially if high power is needed. A cheaper method is to use the galvanostatic operation and to measure continuously the potential and to adapt the cell current manually (or using a computer data acquisition system) in order to adjust the... 

Enzyme reactions can be measured continuously or discontinuously, with each approach having both advantages and drawbacks. 

ELISA assays may be competitive or noncompetitive. As the name imphes, in a competitive ELISA, enzyme-labeled antigen competes with free antigen (the analyte of interest) for a fixed and limited quantity of immobihzed antibody binding sites. After incubation, the microtiter plate (sohd support) is rinsed to remove all unbound species and the enzyme substrate is added in saturating concentration. The conversion of substrate to produce can be measured continuously (kinetic assay) or, more commonly. 

Since 1968, total-oxidant concentrations have been measured continuously with a Mast ozone meter (calibrated by the California Air Resources Board method) from May through September at Rim Forest-Sky Forest.- The fall, winter, and early spring months have generally been omitted until recently, because synoptic patterns are usually not conducive to oxidant accumulation and transport. For example, average maximal hourly oxidant concentrations ffom October through April 1973 and 1974 stayed below 0.10 ppm those for April were 0.10-0.15 ppm. The main data-collection period coincides with the growing season and thus permits a reasonable estimate of the total annual dose of oxidant air pollution received by vegetation. 

It is important to separate conceptually, and in practice, the calibration process from the monitoring process. Photochemical oxidants consisting primarily of ozone were firrt continuously measured in southern California by measuring the color change of potassium iodide solutions brought into contact with the ambient air. This measurement continues to yield valid photochemical-oxidant data in California. However, it has yielded questionable data at ambient air monitoring sites elsewhere in... 

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