Meter definition

Unit of Length Abbreviation Number of Meters Definition... 

The temperature compensator on a pH meter varies the instrument definition of a pH unit from 54.20 mV at 0°C to perhaps 66.10 mV at 60°C. This permits one to measure the pH of the sample (and reference buffer standard) at its actual temperature and thus avoid error due to dissociation equilibria and to junction potentials which have significant temperature coefficients. 

Equations 11.19-11.21 are defined for a potentiometric electrochemical cell in which the pH electrode is the cathode. In this case an increase in pH decreases the cell potential. Many pH meters are designed with the pH electrode as the anode so that an increase in pH increases the cell potential. The operational definition of pH then becomes... 

By contrast, in SI units, the coulomb (C) is the unit of charge and is defined as an ampere second (A sec). To reconcile this with newtons and meters, the units of F and r, respectively, a proportionality constant that is numerically different from unity and which has definite units is required. For charges under vacuum we write... 

In order to increase the precision of realization of the base unit meter, the definition based on the wavelength of a krypton-86 radiation was replaced in 1983 by one based on the speed of light. Also added were the prefixes zetta (Z) for 10, zepto (z) for 10 , yotta (Y) for 10 , and yocto (y) for 10 . 

The easiest thing to do is to get the pump curve from the manufacturer because it has the NPSHr listed at different flows. Nowadays, you can get the pump curve on the Internet with an e-mail to the manufacturer, you can send a fax, or request the curve in the mail or with a local call to the pump representative or distributor. If you wanted to verify the NPSHr on your pump, you ll need a complete set of instrumentation a barometer gauge, compound pressure gauges corrected to the centerline of the pump, a flow meter, a velocity meter, and a thermometer. Definitely, it s easier to get the curve from your supplier. 

Threshold lamit Value - The term refers to toxicity by inhalation. The abbreviation used is TLV. The TLV is usually expressed in units of parts per million (ppm) - i.e., the parts of vapor (gas) per million parts of contaminated air by volume at 25 °C (77°F) and atmospheric pressure. For chemicals that form a fine mist or dust, the concentration is given in milligrams per cubic meter (mg/m ). The TLV is defined as the concentration of the chemical in air that can be breathed for five consecutive eight-hour workdays (i.e., 40 hours per week) by most people without suffering adverse health effiects. This is the definition given by the American Conference of Governmental Industrial Hygienists. 

Specific gravity The weight of a material in kg that would occupy one cubic meter under a definite state of conditions. 

C 0.5012 mol 2 at 15°C). It is clearly unwise to associate a pH meter reading too closely with pH unless under very controlled conditions, and still less sensible to relate the reading to the actual hydrogen-ion concentration in solution. For further discussion of pH mea.surements, see Pure Appl. Chem. 57, 531-42 (1985) Definition of pH Scales, Standard Reference Values, Measurement of pH and Related Terminology. Also C E News, Oct. 20. 1997. p. 6. 

Another important use of RMs is the maintenance of conventional scales. The octane number of gasoline is an example of such a scale. The scale is defined through chemicals. This definition can be realized through RMs. Another example is the pH scale, which is defined by buffers with pH = 4, pH = 7, and pH = 10. These buffers are defined as mixtures of salts, dissolved in water. These define the pH scale can be used by laboratories for the purpose of calibrating their pH meters. 

The numerical values of most physical quantities are expressed in terms of units. The distance between two points, for example, can be specified by the number of meters (or feet, Angstroms, etc.). Similarly, time cap be expressed in seconds, days or, say, years. However, the number of days per year varies from one year to another. The quantities, distance (length) and time, as well as mass, are usually chosen to be primary quantities. In terms of them Newton s second law for the force on an object, can be written as force = mass, distance/(time)2. The definition of the primary quantities allows dimensional expressions to be written, such as [force] — MLT-2 in the present example. Note, however, that in everyday life one speaks of the weight of an object (or a person). Of course the weight is not the mass, but rather the force acting on the object by the acceleration due to gravity [acceleration] = LT 2. 

This equation defines the flow coefficient, Cv. Here, SG is the fluid specific gravity (relative to water), pw is the density of water, and hv is the head loss across the valve. The last form of Eq. (10-29) applies only for units of Q in gpm and hv in ft. Although Eq. (10-29) is similar to the flow equation for flow meters, the flow coefficient Cv is not dimensionless, as are the flow meter discharge coefficient and the loss coefficient (Af), but has dimensions of [L3][L/M]1/2. The value of Cv is thus different for each valve and also varies with the valve opening (or stem travel) for a given valve. Values for the valve Cv are determined by the manufacturer from measurements on each valve type. Because they are not dimensionless, the values will depend upon the specific units used for the quantities in Eq. (10-29). More specifically, the normal engineering (inconsistent) units of Cv are gpm/ (psi)1/2. [If the fluid density were included in Eq. (10-29) instead of SG, the dimensions of Cv would be L2, which follows from the inclusion of the effective valve flow area in the definition of Cv]. The reference fluid for the density is water for liquids and air for gases. 

For the most part, in this book we use SI dimensions and units (SI stands for le systeme international d unites). A dimension is a name given to a measurable quantity (e.g., length), and a unit is a standard measure of a dimension (e.g., meter (for length)). SI specifies certain quantities as primary dimensions, together with their units. A primary dimension is one of a set, the members of which, in an absolute system, cannot be related to each other by definitions or laws. All other dimensions are secondary, and each can be related to the primary dimensions by a dimensional formula. The choice of primary dimensions is, to a certain extent, arbitrary, but their minimum number, determined as a matter of experience, is not. The number of primary dimensions chosen may be increased above the minimum number, but for each one added, a dimensional constant is required to relate two (or more) of them. 

The vehicle for a framework is a generic, or template, form of package. Inside the template, some types and their features can be defined using placeholder names. Looking at its definition in the library, we find that the Observation template has two type placeholders Subject and Observer we have imported that package, substituting Stock and Meter. The sustituted definition becomes part of the model. In other words, whatever attributes and operations are defined for Subject within the template s definition are now defined for Stock. Other names can be substituted, too. The template uses an attribute called value for the aspect of the Subject that we want observed so we substitute it for the Stock s level. 

Soil pH is perhaps the most critical and common soil measurement where a definite amount of water is added before a measurement is made. Soil pH is a particularly complicated measurement because the proton can and does exist as a hydronium ion in the soil solution, as an exchangeable ion on the cation exchange sites, and bonded to various soil constituents. Because of these complexities, a soil sample is usually brought to a standard moisture content before a pH measurement is made. By bringing different soils to a common moisture content, they can be compared and analytical results from different laboratories will be comparable. Although there is a number of ways to measure soil pH, typically it is carried out using a pH meter and a pH electrode. 

In the following some aspects of the guidelines are given in detail. Guideline VDI 3881 consists of four parts. The drafts of parts 1, 2, and 3 were published in the VDI handbook. Part 4 is in preparation. The draft of part 1 was already revised. The new version will be published in a few months. The most important result of the revision is the definition of odour concentration expressed as odour units per cubic meter (GE/m 3). According to this definition one odour unit is the amount of odorants in one cubic meter of air at odour threshold level. The new definition is a real concentration and gives a better form of input parameter for dispersion models. 

At this stage no definite answer can be given about the date and required capacity, but it is generally accepted that by the end of the century, Israel will have to develop 500 to 700 million cubic meters of additional water capacity. Of this 100-200 million cubic meters would probably have to be supplied by desalting. At least a part of the required capacity will be obtained by desalting brackish waters which can not be used directly for agriculture. 

The quantity (symbolized by p) of electrical charge per unit volume, equal to Q/V, with SI units of coulombs per cubic meter. More technically, this definition refers to the volume charge density. See Surface Charge Density... 

The rate constant (sometimes called the specific reaction rate) is commonly designated by k. The SI unit of time is the second (symbolized by s). Thus, unimolecular rate constants are typically expressed in s and unimolecular processes are by definition concentration-independent reactions. A slight difficulty arises regarding SI units and bi- and termolecular rate constants. Concentrations in the SI system would be mol per cubic meter, but in chemistry concentrations are expressed in mobdm (or more commonly mol-L or simply M ). Thus, a bimolecular rate constant typically has units of M s whereas a termolecular rate constant is expressed with units of... 

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