SI Le Systeme International

SI (le Systeme International d UniUs) units are used in many countries to express clinical laboratory and serum drug concentration data. Instead of employing units of mass (such as micrograms), the SI system uses moles (mol) to represent the amount of a substance. A molar solution contains 1 mol (the molecular weight of the substance in grams) of the solute in 1 L of solution. The following formula is used to convert units of mass to moles (mcg/mL to pmol/L or, by substitution of terms, mg/mL to mmol/L or ng/mL to nmol/L). 

The System International [SI] Le Systeme international d Unites officially came into being in October 1960 and has been adopted by nearly all countries, though the amount of actual usage varies considerably. It is based upon 7 principal units, 1 in each of 7 different categories which are given below. Definitions of these basic units are given. Each of these units may take a prefix. From these basic units many other units are derived and named. ... 

SI Le Systeme International d Unites (International System of Units)... 

SI Le Systeme International d Unit s, or the International System of Units, which is the measurement system that is accepted worldwide SI Le Systeme International d Unit s, o el Sistema Internacional de Unidades, que es el sistema de medicidn que se acepta en todo el mundo... 

The units of measurement used in this book are normally SI (Le Systeme International d Unite s, OI, 2006). However, many industrial standards have been developed by companies working with the traditional English/American units (sometimes referred to as customary units), and these are sometimes quoted here. Also, many of the standards that are currently in use are clearly based on the... 

As explained in Chapter 1 the engineering information provided in this book generally uses the SI (Le Systeme international d unites) metric units. However, much of the information to do with regulations and standards, particularly in the United States, is based on the English or customary units such as feet (ft.) and pounds (lb.). In most cases these English measurements have been converted to metric. 

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. 

Bureau internationale de poids et mesures, Le Systeme international d unites (SI), Organisation Intergouvernemental de la Convention du Metres, Sevres, 1998. 

To communicate effectively, scientists rely on a standard system of measurement. As you have learned in previous studies, this system is called the International System of Units (Le systeme international d unites, SI). It allows scientists anywhere in the world to describe matter in the same quantitative language. There are seven base SI units, and many more units that are derived from them. The metre (m), the kilogram (kg), and the second (s) are three of the base SI units. You will learn about two more base units, the mole (mol) and the kelvin (K), later in this book. 

Bureau International des Poids et Mesures, Le Systeme International d9Unites (SI), 6th French and English Edition, BIPM, Sevres 1991. 

Molarity (moles of solute per liter of solution, symbolized by m) is a useful unit for concentration, but it is not recommended for highly accurate measurements by the international unit convention, Le Systeme International d Unites or Systeme International (SI). Nevertheless, we will use molarity in addition to the SI unit of mol m-3. We also note that SI as currently practiced allows the American spelling "liter and "meter as well as the British spelling "litre and "metre. ... 

For many years, most scientists worldwide have used the metric system. In 1960 an international agreement established a system of units called the International System (le Systeme International in French), abbreviated SI. This system is based on the metric system and the units derived from the metric system. The fundamental SI units are listed in Table A2.1. 

The General Conference on Weights and Measures updated the metric system in 1960 and renamed it the International System of Measurements. The system is commonly referred to as SI, which is short for the French name, Le Systeme International d Unites. Scientists from all around the world have adopted SI, and there has been a push in many countries to convert the general population to the SI units. 

In 1960, the metric system was standardized in the form of Le Systeme International d Unites (SI), which is French for the International System of Units. These SI units were accepted by the international scientific community as the system for measuring aU quantities. 

SI units (le Systeme International d Unites) are used to express clinical... 

The abbreviation SI comes from the French le Systeme International. 

The International System of Units, abbreviated as SI (from the French name Le Systeme International d Unites), was established in 1960 by the 11th General Conference on Weights and Measures (CGPM) as the modern metric system of measurement. The core of the Si is the seven base units for the physical quantities length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity. These base units are ... 

SI Abbreviation for the worldwide standard prepared by the International System of Units. SI is from the French name Le Systeme International d Unites. This standard gives guidance for application of the modernized metric system developed and maintained by the Group Conference on Weights and Measures (CGPM for the official French name Conference Generale des Poids et Mesures). The SI abbreviations were adopted by the eleventh CGPM in 1960. See Appendix B, Conversion Tables decimal number system measurement meter number marker. 

SI n. (1) Abbreviation for silicon or polydi-methylsiloxane. (2) Abbreviation for international systems of units , derived from the official French name, Le System International d Unites. An internationally agreed coherent system of units, derived from the MKS system, now in use for all scientific purposes and thereby replacing the cgs system and the f.p.s. system. The seven basic units are the metric (symbol m), kilogram (kg), second (s), ampere (A), Kelvin (K), mole (mol), and candela (cd). The radian (rad) and steradian (sr) are supplementary units. Derived units include the hertz (Hz), newton (N), joule (J), watt (W), coulomb (C), volt (V), farad (F), ohm (Q), weber (wb), tesla (T), henry (H), lumen (Im), and lux (lx). 

In 1960, the General Conference on Weights and Measures adopted the International System of Units (or SI, after the French, Le Systeme International d Unites). The International Bureau of Weights and Standards in Sievres, France, houses the official platinum standard measures by which all other standards are compared. The SI system has seven base units from which other units are calculated. Table 2.1 gives the SI units used in chemistry. 

In this chapter, we introduce the International System of Units (SI) on the basis of the SI brochure "Le Systeme international d unites (SI)" [2.1], supplemented by [2.2]. We give a short review of how the SI was worked out and who is responsible for the further development of the system. Following the above-mentioned publications, we explain the concepts of base physical quantities and derived physical quantities on which the SI is founded, and present a detailed description of the SI base units and of a large selection of SI derived units. We also discuss a number of non-SI units which still are in use, especially in some specialized fields. A table (Table 1.2-17) presenting the values of various energy equivalents closes the section. 

The development of the metric system, which served as the basis of the International System of Units (Le Systeme International d Unites known as SI), occurred during the French Revolution in the mid-eighteenth century. This coincided with the beginning of the age of modern science, especially chemistry and physics, as the value of physical measurements in the conduct of those pursuits became apparent. As scientific activities became more precise and founded on sound theory, the common nature of science demanded an equally consistent system of units and measurements. The units in the SI have been defined by international accord to provide consistency in all fields of endeavor. The basic units are defined for only seven fundamental properties of matter. All other consistent units are derived as functions of these seven fundamental units. 

A dimensional system comprises the fewest dimensions necessary to quantify a particular feature of Nature. The necessary dimensions form a basis set with which to describe our perceptions of Nature. The dimension basis set for the Le Systeme International d Unites (SI units) is length [L], mass [M], time [T], thermodynamic temperature [9], amount of substance [N], electric current [A], and luminous intensity [CD]. 

The International System of Units (SI) is the modem metric system of measurement. The abbreviation SI is derived from the French Le Systeme International d UniUs. The ll" General Conference on Weights and Measures (CGPM, Confirmee Ginirale des Poids et Mesures) estabhshed the system in 1960. The seven basic units in the SI system are shown in Table 1.2, the recommended prefixes in Table 1.3 and derived units of general character are shown in Table 1.4. Some constants of importance for this book are collected in Table 1.5. These tables are collected at the end of this chapter (see pp. 14ff.). 

In 1960 the General Conference of Weights and Measures adopted the International System of units (or SI, after the French le Systeme International d Unites), which is a particular choice of metric units. This system has seven SI base units, the SI units from which all others can be derived. Table 1.2 lists these base units and the symbols used to represent them. In this chapter, we will discuss four base quantities length, mass, time, and temperature. ... 

A new classification of pore sizes is proposed. It is based on prefixes defined by the Bureau International des Poids et Mesures under Le Systeme International d Unit s (SI) [1] (in particular nano-, micro- and milli-), unlike the current classification scheme defined by the International Union of Pure and Applied Chemistry (lUPAC) [2]. Thus the new classification is also consistent with other common scientific terms based on SI prefixes such as nanotechnology [3]. Further advantages are that unlike the lUPAC scheme - which is derived from physical adsorption phenomena in pores narrower than 50 nm - the new classification is entirely decoupled from any physieo-ehemieal system or process and is not biased towards small pores. However, the proposed new scheme is more complicated than the current lUPAC one, especially regarding suh-divisions of the main pore size classes. Also, the term micropore occurs in both schemes, which makes them incompatihle, at least over the micropore size range as defined in the new classification. 

Note The accepted SI unit for mass is the kilogram (kg). SI is from French meaning Le Systeme International d unites. However, as the mass of an atom, ion, or molecule is significantly less than the standard SI unit, specific mass units needed to be introduced. That accepted by the SI is the Dalton (Da). More commonly used, however, is the numerically equivalent unified atomic mass unit (u). Before 1961, the term atomic mass unit (amu) was also in use. 1 Da equates to 1.6605 X 10-27 kg. 

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