Inch , conversion units

The unit inches in the denominator of the conversion factor cancels the unit inches in the given data (8.50 inches). The unit centimeters in the numerator of the conversion factor becomes the unit of the final answer. Because the numerator and denominator of a conversion factor are equal, multiplying any quantity by a conversion factor is equivalent to multiplying by the number 1 and so does not change the intrinsic value of the quantity. The length 8.50 in. is the same as the length 21.6 cm. 

It is necessary to select the type of fiber that will offer the most resistance to breakdown normally caused by chemical, temperature and mechanical conditions of the filter process. Tables 3 through 5 can serve as rough guides to proper media selection. Table 6 provides linear conversion units between mesh size, inches and... 

From Table 2-3, you can find that 1 in. = 2.54 cm. Start with the given quantity (22 cm) and multiply by the conversion factor (written so that centimeters, the unit you are converting from, is on the bottom and inches, the unit you are converting to, is on the top)... 

Unear Umts. The following procedure is used for converting linear units to the proper number of significant places the maximum and minimum limits in inches are calculated. The corresponding two values are converted exacdy into millimeters by multiplying each by the conversion factor 1 in. = 25.4 mm. The results are rounded in accordance with Table 4. 

Since it is often difficult to visualise the extent of attack in terms of depth from such mass-loss units as mdd, it is common practice to convert these mdd figures into others to indicate depth of penetration, i.e. inches per year (ipy), mils or mm y" . Such calculations suffer from the same defects as the mdd figures in that they take into account neither changes in corrosion rates with time nor non-uniform distribution of corrosion. However, since such conversions are often made it is desirable for the initial reporter of the test results to make the calculations accurately and to report corrosion rates in both mdd and mm y or similar units. 

The unit conversion of t from inches to feet does not affect the optimum LID), nor do the values of p and S, which are multiplicative constants. The modified objective function, substituting Equation (/) in Equation (j), is therefore... 

You can work all unit conversion problems by this procedure. In some cases, such as the miles to feet problem, only one step is necessary. In other cases, such as the miles to inches problem, more than one step is necessary. However, all steps are of the same type. You will cancel one unit and get a new unit. This process continues until the new unit matches the one that you are seeking. 

To use the proportion method to convert units, set up a proportion as described in Chapter 5. Keep the units consistent on both sides of the proportion. For example, if you want to convert 50.8 centimeters to inches, set up a proportion, such as meter = centimeter and substitute in tie given values on one side, tie conversion factor on tie other yyq = -yyy. Cross-multiply to get 2.54 xs=lx 50.8. Now, divide 50.8 by 2.54 to get n = 20 inches. 

Divide 7,620 by 609.6 to get 12.5 inches per second. As you can see from this example, dimensional analysis is an efficient way to convert measurement units when there are several conversions to be made. 

Note When U.S. units are used, the constant 1000 must be changed to 12. This constant is the conversion factor to change millimeters to meters or inches to feet. 

The plcint shown in Figure 1 consists of a water pretreatment plant and four sepairate blocks of "Permasep" units. All blocks cire fed by the Scime high pressure pump, cuid each block consists of 4-inch modules, reject-staged in a 2 to 1 ratio. The total conversion is about 70 percent — this means that cibout 70 percent of the feed water is converted to product, with 30 percent discarded as a brine stream. 

A conversion factor simply uses your knowledge of the relationships between units to convert from one unit to another. For example, if you know that there are 2.54 centimeters in every inch (or 2.2 pounds in every kilogram or 101.3 kilopascals in every atmosphere), then converting between those units becomes simple algebra. Peruse Table 2-3 for some useful conversion factors. And remember If you know the relationship between any two units, you can build your own conversion factor to move between those units. 

You don t need to know all possible unit conversions (between meters and inches, for example). Instead of memorizing or looking up conversion factors between all types of units, you can memorize just a handful of conversion factors and use them one after another, letting the units guide you each step of the way. 

In this chapter, I offer suggestions on how to choose the unit or units and then how to work with the unit or units you ve chosen. This chapter also covers the tricky conversions of square feet to square inches or cubic yards to cubic feet. And, of course, no discussion of units is complete without introducing meters and kilograms, so you get conversions involving metric and English measures. 

You may encounter questions that ask you to convert between units of measurement in length, weight, or time. To convert from a smaller unit (such as inches) to a larger unit (such as feet), divide the smaller unit by the number of those units necessary to equal the larger unit. To convert from a larger unit to a smaller unit, multiply the larger unit by the conversion number. 

The third calculation is the conversion of pressure units from pounds per square inch read from a guage (psig) to pounds per square inch absolute (psia). Strictly speaking, the value of barometric pressure in psi read from a barometer at the time the pressure gauge was calibrated should be added to psig to get psia. At sea level, a value of 14.7 psi is usually sufficiently accurate. 

The dimensional-analysis method gives the right answer only if the equation is set up so that the unwanted units cancel. If the equation is set up in any other way, the units won t cancel properly, and you won t get the right answer. Thus, if you were to multiply your height in inches by the incorrect conversion factor inches per meter, you would end up with an incorrect answer expressed in meaningless units ... 

This scheme differs from the various systems in use in industry and academia in that it uses the mole instead of the cc(STP) to express the quantity of matter being transported, the pascal rather than the atmosphere or the cm. Hg. to express pressure, the meter rather than the mil, the inch, or the centimeter to express length, and the second rather than the day to express time. Our experience indicates that the existing variety of unit systems leads to confusion and that calculations of related physical properties such as permeabilities, diffusion coefficients, and solubilities are easier using the SI units. More modern measurement systems which detect permeants by means of the electrical currents generated by individual atoms are easier to analyze when one uses moles rather than cc(STP) to express the amount of matter undergoing transport. Applications involving the transport of mixed permeant species are also easier to deal with on a molar basis. Conversion tables between the SI units and customary units are provided on the SRM certificate and in the appropriate standards documents (4, 5). ... 

Chemical engineers and scientists will know that the data they use are expressed in a great variety of different units. The length of a rod may be variously described as 12 in, 1 ft, 0.3048 m, 304.8 mm, etc. These lengths are all equivalent. Inch, foot, metre and millimetre define the size of the unit and 12, 1, 0.3048 and 304.8 define the number of the units in each system. There are many useful references in the literature that discuss conversion between units and tabulate conversion factors.1,4,5... 

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