System SI Metric Units

International System of Units (SI), to the extent possible, is used in most specifications, assays, and tests in this Food Chemicals Codex. The SI metric units, and other units and abbreviations commonly employed, are as follows ... 

The International Metric System (SI) of units has been used throughout this subsection. Where possible, the estimation equations are set up in dimensionless groups. This makes transparent any conversion factors that should be applied to obtain the property in a desired set of units and eliminates the requirement of specific units for variables. For example, rather than use as a variable with defined units, the dimensionless group P / Pa is used. When a value for P expressed in... 

In the past, several systems of metric units were commonly used by scientists, each system having its advantages and disadvantages. Recently international agreement was reached on the use of a single set of units for the various physical quantities, as well as on a recommended set of symbols for the units and for the physical quantities themselves. The SI will be used in this book with only a few additions. Because of its importance in defining the standard state of pressure, the atmosphere will be retained as a unit of pressure in... 

We use the International System (SI) of units, commonly referred to as the metric system, to measure in engineering and scientific fields. In the metric system, we... 

Consistent units of measure used in the calculation formulas (calculators) are a must. For example, each calculator is either in US or SI (metric) units (Appendix B). To use these calculators, it may be necessary to convert the units of measure to match those in the formula (Tables 4-1 and 4-2). The calculators here are simplified, often with the constants already incorporating the conversion factors. The derivation of the simplified calculators is given in Appendix D. Chemical feed calculators are provided for the most common treatment situations. Combinations of these calculators may he needed for other treatment systems. 

NOTE Copyright SPE-AIME, The SI Metric System of Units and SFE s Tentative Mehic Standai d, Society of Petroleum Engineers, Dallas, 1977. 

Applicable dimensional units are shown individuaUy with each equation. The International Metric System (SI) is used when feasible otherwise commonly used U.S. engineering units are employed. The reader is referred to Sec. 1 for unit conversion fac tors. 

Metric Units of Measiu ement. For the purpose of this Code, metric units of measurement are in accordance with the modernized metric system known as the International System of Units (SI). 

As you can see from this discussion, a wide number of different units can be used to express measured quantities in the metric system. Ibis proliferation of units has long been of concern to scientists. In 1960 a self-consistent set of metric units was proposed. This so-called International System of Units (SI) is discussed in Appendix 1. The SI units for the four quantities discussed are... 

Scientists measure many different quantities—length, volume, mass (weight), electric current, temperature, pressure, force, magnetic field intensity, radioactivity, and many others. The metric system and its recent extension, Systeme International d Unites (SI), were devised to make measurements and calculations as simple as possible. In this chapter, length, area, volume, and mass will be introduced. Temperature will be introduced in Sec. 2.7 and used extensively in Chap. 11. The quantities to be discussed here are presented in Table 2-1. Their units, abbreviations of the quantities and units, and the legal standards for the quantities are also included. 

SI (Systeme International d Unites) a modern version of the metric system. significant digits significant figures. 

Basic study skills needed to study chemistry Macroscopic and microscopic properties of matter The SI (Metric) system Basic problem solving techniques Unit Conversion Method Significant figures... 

Chemistry is full of calculations. Our basic goal is to help you develop the knowledge and strategies you need to solve these problems. In this chapter, you will review the Metric system and basic problem solving techniques, such as the Unit Conversion Method. Your textbook or instructor may call this problem solving method by a different name, such as the Factor-Label Method and Dimensional Analysis. Check with your instructor or textbook as to for which SI (Metric) prefixes and SI-English relationships will you be responsible. Finally, be familiar with the operation of your calculator. (A scientific calculator will be the best for chemistry purposes.) Be sure that you can correctly enter a number in scientific notation. It would also help if you set your calculator to display in scientific notation. Refer to your calculator s manual for information about your specific brand and model. Chemistry is not a spectator sport, so you will need to Practice, Practice, Practice. 

The measurement system that you will most likely encounter is the SI (Metric) system. Each quantity (such as mass and volume) has a base unit and a prefix that modifies the base unit. The prefixes are the same for all quantities and are based on a decimal system. Below are some basic SI units we will introduce others in later chapters ... 

The "Systeme International" (S ) units, based on the metric system, were designed to achieve maximum internal consistency. The SI system is based on the following set of defined units ... 

The metric system, or Systeme International d Unites (SI system as it is commonly known), is the predominant system of measurement in the world. In fact, the United States is one of only about three countries that do not commonly use the metric system. The metric system attempts to eliminate odd and often difircult-to-remember conversions for measurements (5,280 feet in a mile, for example). It is a decimal-based system with standard terminology for measurements of length, volume, and mass (weight). It also uses standard prefixes to measure multiples of the standard units. 

In 1960 the International General Conference on Weights and Measures adopted an improved form of the metric system, The International System of Units (SI). The units of mass, length, and time are the kilogram (kg), meter (m), and second (s). The following prefixes are used for fractions and multiples ... 

SI (Systeme International de Unites) The International System of units a collection of definitions of units and their employment. It is an extension and rationalization of the metric system. 

Under an international agreement concluded in 1960, scientists throughout the world now use the International System of Units for measurement, abbreviated SI for the French Systeme Internationale d Unites. Based on the metric system, which is used in all industrialized countries of the world except the United States, the SI system has seven fundamental units (Table 1.3). These seven fundamental units, along with others derived from them, suffice for all scientific measurements. We ll look at three of the most common units in this chapter—those for mass, length, and temperature—and will discuss others as the need arises in later chapters. 

Convert 3.50 yards to (a) millimeters, (b) meters. According to Table 1-2, the conversion factor used to move between the English and metric system (SI) units is 1 in/2.54cm (2.54 x 10-2 m). 

The SI (metric) system of units is the primary one for the text. Because the Btu-ft-pound system is still in wide use, answers and intermediate steps to examples are occasionally stated in these units. A few examples and problems are completely in English units. Some figures have dual coordinates that show both systems of units. These displays will enable the student to develop a bilingual capability during the period before full metric conversion is achieved. 

The relationship between shearing stress and rate of shear can be used to define the flow properties of materials. In the simplest case, the shearing stress is directly proportional to the mean rate of shear x = fly (Figure 8-5). The proportionality constant T is called the viscosity coefficient, or dynamic viscosity, or simply the viscosity of the liquid. The metric unit of viscosity is the dyne.s cm-2, or Poise (P). The commonly used unit is 100 times smaller and called centiPoise (cP). In the SI system, t is expressed in N.s/m2. or... 

The net quantity of contents (in terms of weight or mass, measure, or numerical count) shall be separately and accurately stated in a uniform location upon the principal display panel of that label, using the most appropriate units of both the customary inch/pound system of measure, as provided in paragraph (3) of this subsection, and, except as provided in paragraph (3)(A)(ii) or paragraph (6) of this subsection, the SI metric system ... 

The metric system and its more modem counterpart SI (for Systeme International d Unites) are systems of units designed to make calculations as easy as possible. It was designed to make every word mean one and only one thing. Its subdivisions and multiples of units are powers of 10 times a primary unit. Each of its prefixes means the same thing, no matter what unit it is attached to. The abbreviations for the quantities and prefixes are easy to remember. All these features have been built into the metric system to make it easy. Contrast this lack of ambiguity with the ambiguity in the English system, as illustrated in Example 2.4. 

The cubic meter (m ) is the primary unit of volume in SI. A smaller unit, the liter, is the primary unit of volume in the metric system. The abbreviation for hter is L. We need to know both the cubic meter and the liter. Table 2.3 summarizes the primary metric units of distance, mass, and volume. 

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