Measurements conversion factors

A record of all calculations performed in connection with the test, including units of measure, conversion factors, and equivalency factors. 

Quantity Per Units of Measure Conversion Factors Work Centers Conversion Yield Factors Approval... 

Flanagan RJ. Guidelines for the interpretation of analytical toxicology results and unit of measurement conversion factors. Ann Chn Biochem 1998 35 261-8. 

Manufacturing capacity in hours for production line t at facility h Unit of measure conversion factor for product p at conversion facility i (standard units/ton). (Note that different measurement units may be used at different echelons, such as tons or standard units for produefion, cubic meters for storage and distribution, and standard units or cases for sales.)... 

The system of atomic units was developed to simplify mathematical equations by setting many fundamental constants equal to 1. This is a means for theorists to save on pencil lead and thus possible errors. It also reduces the amount of computer time necessary to perform chemical computations, which can be considerable. The third advantage is that any changes in the measured values of physical constants do not affect the theoretical results. Some theorists work entirely in atomic units, but many researchers convert the theoretical results into more familiar unit systems. Table 2.1 gives some conversion factors for atomic units. 

Pressure is defined as force per unit of area. The International System of Units (SI) pressure unit is the pascal (Pa), defined as 1.0 N /m. Conversion factors from non-SI units to pascal are given in Table 1 (see also Units and conversion factors front matter). An asterisk after the sixth decimal place indicates that the conversion factor is exact and all subsequent digits are 2ero. Relationships that are not followed by an asterisk are either the results of physical measurements or are only approximate. The factors are written as numbers greater than 1 and less than 10, with 6 or fewer decimal places (1). 

Ash and Inorganic Constituents. Ash may be measured gravimetdcaHy by incineration in the presence of sulfudc acid or, more conveniendy, by conductivity measurement. The gravimetric result is called the sulfated ash. The older carbonate ash method is no longer in use. Ash content of sugar and sugar products is approximated by solution conductivity measurements using standardized procedures and conversion factors. 

B is the potential of the reference electrode, without whose identification the potential U is undefined. Potentials are conveniently calculated against a standard reference value. Section 3.2 contains further details on reference electrodes and conversion factors. Section 3.3 describes practical methods for measuring potential in the case of flowing currents. 

Converting a measurement from one unit to anotlier can conveniently be accomplished by using unit conversion factors, tliese factors are obtained from tlie simple equation that relates tlie two units numerically. The following is an example of a unit conversion factor... 

Toxicity alucs for carcinogenic effects also can be c.xprcsscd in terms of risk per unit concentration of the substance in the medium where human contact occurs. These measures, called unit risks, are calculated by dividing the slope factor by 70 kg and multiplying by the inhalation rate (20 m /day) or the water consumption rate (2 L/day), respecti ely, for risk associated with unit concentration in air or water. Where an absorption fraction less than 1.0 has been applied in deriving the slope factor, an additional conversion factor is necessary in the calculation of unit risk so that the unit risk will be on an administered dose basis. The standardized duration assumption for unit risks is understood to be continuous lifetime c.xposure. Hence, when there is no absorption conversion required ... 

It is often necessary to convert a measurement expressed in one unit (e.g., cubic centimeters) to another unit (liters). To do this we follow what is known as a conversion factor approach. For example, to convert a volume of 536 cm3 to liters, the relation... 

Use conversion factors to change the units of a measured quantity. 

Designers, manufacturers, and operators of boilers continue to use many of these terms, without undue deference to unit standardization, to define, measure, and report on plant steam-raising capacities power output) and operating parameters. (In continuance of this common practice therefore, many of these various terms are freely used in discussions throughout this book.) However, to familiarize the reader and minimize confusion, some energy terms and notes are provided here. A more complete list of units and conversion factors is provided in the appendix. 

A.20 Use the conversion factors in Appendix IB and inside the back cover to express the following measurements in the... 

Integers and exact numbers In multiplication or division by an integer or an exact number, the uncertainty of the result is determined by the measured value. Some unit conversion factors are defined exactly, even though they are not whole numbers. For example, 1 in. is defined as exactly 2.54 cm and the 273.15 in the conversion between Celsius and Kelvin temperatures is exact so 100.000°C converts into 373.150 K. 

BEIs apply to 8 hr exposures, five days a week. However, BEIs for altered working schedules can be extrapolated on pharmacokinetic and pharmacodynamic bases. BEIs should not be applied, either directly or through a conversion factor, to the determination of safe levels for non-occupational exposure to air and water pollutants, or food contaminants. The BEIs are not intended for use as a measure of adverse effects or for diagnosis of occupational illness. 

For a comparison of experimental Mossbauer isomer shifts, the values have to be referenced to a common standard. According to (4.23), the results of a measurement depend on the type of source material, for example, Co diffused into rhodium, palladium, platinum, or other metals. For Fe Mossbauer spectroscopy, the spectrometer is usually calibrated by using the known absorption spectrum of metallic iron (a-phase). Therefore, Fe isomer shifts are commonly reported relative to the centroid of the magnetically split spectrum of a-iron (Sect. 3.1.3). Conversion factors for sodium nitroprusside dihydrate, Na2[Fe(CN)5N0]-2H20, or sodium ferrocyanide, Na4[Fe(CN)]6, which have also been used as reference materials, are found in Table 3.1. Reference materials for other isotopes are given in Table 1.3 of [18] in Chap. 1. 

Quantitation is performed by the calibration technique. Construct a new calibration curve with methomyl oxime standard solutions (0.2, 0.4, 0.6, 0.8 and 1.0 xgmL in acetone) for each set of analyses. Plot the peak area against the injected amount of methomyl oxime on logarithmic paper. As the amount of alanycarb is measured in terms of its oxime derivative, a conversion factor of 3.8 (the molecular weight ratio of alanycarb to methomyl oxime) should be applied to obtain the net amount. The injection volume should be kept constant as the peak area varies with the injection volume in flame photometric detection. Before each set of measurements, check the GC system by injecting more than one standard solution containing ca 2-10 ng of methomyl oxime. 

Analytical methods for quantifying americium in environmental samples are summarized in Table 7-2. The methods that are commonly used in the analysis of americium based on activity are gross a analysis, a-spectrometry and gamma-ray spectrometry. MS detection techniques are used to measure the mass of americium in environmental samples. (The mass-activity conversion factor for 241Am is 0.29 (lCi/ lg or 3.43 ig/ p,Ci [Harvey etal. 1993]). 

Since 7 , is not an experimentally measurable quantity, it is useful to insert the solution for Ts (from the Clausius-Clapeyron equation) and solve for W h as an explicit function of RH0 and RHC. VanCampen et al. showed (using sample algebraic approximations and conversion factors) that substituting for Ts in Eq. (35) gives the useful solution... 

In measurement sciences, calibration is an operation that establish a relationship between an output quantity, qouU with an input quantity, q m for a measuring system under specified conditions (qin qout) The result of calibration is a model that may have the form of a conversion factor, a mathematical equation, or a graph. By means of this model, then it is possible to estimate q -values from measured q0Ut-values (qout qin) as can be seen in an abstracted form in Fig. 6.1. 

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