What is a unit of measurement? Electrical quantities and units of measurement

UNITS OF MEASUREMENT, see UNITS OF WEIGHTS AND MEASURES ... Scientific and technical encyclopedic dictionary

Units- specific values, to the Crimea are assigned numerical values ​​equal to 1. C E. and. they compare and express in them other quantities that are homogeneous with them. By the decision of the General Conference on Weights and Measures (1960), the International System of Units was introduced. SI as a single... ... Dictionary of microbiology

Units- (Mida at Mishkal) Measures of weight, length, area and volume were used in ancient times, mainly for the needs of trade. There are almost no clearly defined unitary measures in the Bible, and it is not easy to establish the relationships between them. At the same time, in... Encyclopedia of Judaism

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Units of information- serve to measure the volume of information of a value calculated logarithmically. This means that when several objects are considered as one, the number of possible states is multiplied, and the amount of information is added. It doesn’t matter... ... Wikipedia

Pressure units- Pascal (newton per square meter) Bar Millimeter of mercury (torr) Micron of mercury (10−3 torr) Millimeter of water (or water) Atmosphere Physical atmosphere Technical atmosphere Kilogram force per square centimeter, ... ... Wikipedia

UNITS OF MEASUREMENT OF INFORMATION VOLUME- The basis for measuring large amounts of information is the byte. Larger units of measurement: kilobyte (1 KB = 1024 bytes), megabyte (1 MB = 1024 KB = 1048576 bytes), gigabyte (1 GB = 1024 MB = 1073741824 bytes). For example, on a sheet... ... Dictionary of business terms

Flow units- Units of flow measurement are a system of measures established in the practice of river flow research, designed to study changes in the water content of rivers over a given period of time. The units of flow measurement include: Instantaneous (second) ... Wikipedia

UNITS OF MEASUREMENT OF PHYSICAL QUANTITIES- quantities that, by definition, are considered equal to unity when measuring other quantities of the same kind. The standard unit of measurement is its physical implementation. Thus, the standard unit of measurement, meter, is a rod 1 m long. In principle, one can imagine... ... Collier's Encyclopedia

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The method for setting temperature values ​​is the temperature scale. Several temperature scales are known.

• Kelvin scale(named after the English physicist W. Thomson, Lord Kelvin).
  Unit designation: K(not “degree Kelvin” and not °K).
  1 K = 1/273.16 - part of the thermodynamic temperature of the triple point of water, corresponding to the thermodynamic equilibrium of a system consisting of ice, water and steam.
• Celsius(named after the Swedish astronomer and physicist A. Celsius).
  Unit designation: °C .
  In this scale, the melting temperature of ice at normal pressure is taken to be 0°C, and the boiling point of water is 100°C.
  The Kelvin and Celsius scales are related by the equation: t (°C) = T (K) - 273.15.
• Fahrenheit(D. G. Fahrenheit - German physicist).
  Unit symbol: °F. Widely used, particularly in the USA.
  The Fahrenheit scale and the Celsius scale are related: t (°F) = 1.8 · t (°C) + 32°C. In absolute value, 1 (°F) = 1 (°C).
• Reaumur scale(named after the French physicist R.A. Reaumur).
  Designation: °R and °r.
  This scale is almost out of use.
  Relation to degrees Celsius: t (°R) = 0.8 t (°C).
• Rankin Scale (Rankine)- named after the Scottish engineer and physicist W. J. Rankin.
  Designation: °R (sometimes: °Rank).
  The scale is also used in the USA.
  Temperature on the Rankine scale is related to temperature on the Kelvin scale: t (°R) = 9/5 · T (K).

Basic temperature indicators in units of measurement of different scales:

The SI unit of measurement is meter (m).

• Non-system unit: Angstrom (Å). 1Å = 1·10-10 m.
• Inch(from Dutch duim - thumb); inch; in; ´´; 1´ = 25.4 mm.
• Hand(English hand - hand); 1 hand = 101.6 mm.
• Link(English link - link); 1 li = 201.168 mm.
• Span(English span - span, scope); 1 span = 228.6 mm.
• Foot(English foot - leg, feet - feet); 1 ft = 304.8 mm.
• Yard(English yard - yard, corral); 1 yd = 914.4 mm.
• Fat, face(English fathom - measure of length (= 6 ft), or measure of volume of wood (= 216 ft 3), or mountain measure of area (= 36 ft 2), or fathom (Ft)); fath or fth or Ft or ƒfm; 1 Ft = 1.8288 m.
• Cheyne(English chain - chain); 1 ch = 66 ft = 22 yd = = 20.117 m.
• Furlong(eng. furlong) - 1 fur = 220 yd = 1/8 mile.
• mile(English mile; international). 1 ml (mi, MI) = 5280 ft = 1760 yd = 1609.344 m.

The SI unit is m2.

• Square foot; 1 ft 2 (also sq ft) = 929.03 cm 2.
• Square inch; 1 in 2 (sq in) = 645.16 mm 2.
• Square fathom (fesom); 1 fath 2 (ft 2; Ft 2; sq Ft) = 3.34451 m 2.
• Square Yard; 1 yd 2 (sq yd)= 0.836127 m 2 .

Sq (square) - square.

The SI unit is m3.

• Cubic foot; 1 ft 3 (also cu ft) = 28.3169 dm 3.
• Cubic Fathom; 1 fath 3 (fth 3; Ft 3; cu Ft) = 6.11644 m 3.
• Cubic Yard; 1 yd 3 (cu yd) = 0.764555 m 3.
• Cubic inch; 1 in 3 (cu in) = 16.3871 cm 3.
• Bushel (UK); 1 bu (uk, also UK) = 36.3687 dm 3.
• Bushel (USA); 1 bu (us, also US) = 35.2391 dm 3.
• Gallon (UK); 1 gal (uk, also UK) = 4.54609 dm 3.
• Gallon liquid (USA); 1 gal (us, also US) = 3.78541 dm 3.
• Gallon dry (USA); 1 gal dry (us, also US) = 4.40488 dm 3.
• Jill (gill); 1 gi = 0.12 l (US), 0.14 l (UK).
• Barrel (USA); 1bbl = 0.16 m3.

UK - United Kingdom - United Kingdom (Great Britain); US - United Stats (USA).

Specific volume

The SI unit of measurement is m 3 /kg.

• ft 3/lb; 1 ft3 / lb = 62.428 dm 3 / kg .

The SI unit of measurement is kg.

• Pound (trading) (English libra, pound - weighing, pound); 1 lb = 453.592 g; lbs - pounds. In the system of old Russian measures 1 lb = 409.512 g.
• Gran (English grain - grain, grain, grain); 1 gr = 64.799 mg.
• Stone (eng. stone - stone); 1 st = 14 lb = 6.350 kg.

Density, incl. bulk

The SI unit of measurement is kg/m3.

• lb/ft 3 ; 1 lb/ft 3 = 16.0185 kg/m 3.

Linear density

The SI unit is kg/m.

• lb/ft; 1 lb/ft = 1.48816 kg/m
• Pound/Yard; 1 lb / yd = 0.496055 kg/m

Surface density

The SI unit is kg/m2.

• lb/ft 2 ; 1 lb / ft 2 (also lb / sq ft - pound per square foot) = 4.88249 kg/m2.

Linear speed

The SI unit is m/s.

• ft/h; 1 ft/h = 0.3048 m/h.
• ft/s; 1 ft/s = 0.3048 m/s.

The SI unit is m/s2.

• ft/s 2 ; 1 ft/s2 = 0.3048 m/s2.

Mass flow

The SI unit is kg/s.

• lb/h; 1 lb/h = 0.453592 kg/h.
• lb/s; 1 lb/s = 0.453592 kg/s.

Volume flow

The SI unit of measurement is m 3 /s.

• ft 3 /min; 1 ft 3 / min = 28.3168 dm 3 / min.
• Yard 3/min; 1 yd 3 / min = 0.764555 dm 3 / min.
• Gpm; 1 gal/min (also GPM - gallon per min) = 3.78541 dm 3 /min.

Specific volume flow

• GPM/(sq·ft) - gallon (G) per (P) minute (M)/(square (sq) · foot (ft)) - gallons per minute per square foot;
  1 GPM/(sq ft) = 2445 l/(m 2 h) 1 l/(m 2 h) = 10 -3 m/h.
• gpd - gallons per day - gallons per day (day); 1 gpd = 0.1577 dm 3 /h.
• gpm - gallons per minute - gallons per minute; 1 gpm = 0.0026 dm 3 /min.
• gps - gallons per second - gallons per second; 1 gps = 438 10 -6 dm 3 /s.

Consumption of sorbate (for example, Cl 2) when filtering through a layer of sorbent (for example, activated carbon)

• Gals/cu ft (gal/ft 3) - gallons/cubic foot (gallons per cubic foot); 1 Gals/cu ft = 0.13365 dm 3 per 1 dm 3 of sorbent.

The SI unit of measurement is N.

• Pound-force; 1 lbf - 4.44822 N. (An analogue of the name of the unit of measurement: kilogram-force, kgf. 1 kgf = = 9.80665 N (exact). 1 lbf = 0.453592 (kg) 9.80665 N = = 4 .44822 N 1N=1 kg m/s 2
• Poundal (English: poundal); 1 pdl = 0.138255 N. (Poundall is the force that gives a mass of one pound an acceleration of 1 ft/s 2, lb ft/ s 2.)

Specific gravity

The SI unit of measurement is N/m 3 .

• lbf/ft 3 ; 1 lbf/ft 3 = 157.087 N/m 3.
• Poundal/ft 3 ; 1 pdl/ft 3 = 4.87985 N/m 3.

SI unit of measurement - Pa, multiple units: MPa, kPa.

In their work, specialists continue to use outdated, canceled or previously optionally accepted units of pressure measurement: kgf/cm 2; bar; atm. (physical atmosphere); at(technical atmosphere); ata; ati; m water Art.; mmHg st; torr.

The following concepts are used: “absolute pressure”, “excess pressure”. There are errors when converting some pressure units into Pa and its multiples. It should be taken into account that 1 kgf/cm 2 is equal to 98066.5 Pa (exactly), that is, for small (up to approximately 14 kgf/cm 2) pressures with sufficient accuracy for work the following can be accepted: 1 Pa = 1 kg/(m s 2) = 1 N/m 2. 1 kgf/cm 2 ≈ 105 Pa = 0.1 MPa. But already at medium and high pressures: 24 kgf/cm 2 ≈ 23.5 105 Pa = 2.35 MPa; 40 kgf/cm2 ≈ 39 · 105 Pa = 3.9 MPa; 100 kgf/cm 2 ≈ 98 105 Pa = 9.8 MPa etc.

Ratios:

• 1 atm (physical) ≈ 101325 Pa ≈ 1.013 105 Pa ≈ ≈ 0.1 MPa.
• 1 at (technical) = 1 kgf/cm 2 = 980066.5 Pa ≈ 105 Pa ≈ 0.09806 MPa ≈ 0.1 MPa.
• 0.1 MPa ≈ 760 mm Hg. Art. ≈ 10 m water. Art. ≈ 1 bar.
• 1 Torr (tor) = 1 mm Hg. Art.
• lbf/in 2 ; 1 lbf/in 2 = 6.89476 kPa (see below: PSI).
• lbf/ft 2 ; 1 lbf/ft 2 = 47.8803 Pa.
• lbf/yd 2 ; 1 lbf/yd 2 = 5.32003 Pa.
• Poundal/ft 2 ; 1 pdl/ft 2 = 1.48816 Pa.
• Foot water column; 1 ft H 2 O = 2.98907 kPa.
• Inch of water column; 1 in H 2 O = 249.089 Pa.
• Inch of mercury; 1 in Hg = 3.38639 kPa.
• PSI (also psi) - pounds (P) per square (S) inch (I) - pounds per square inch; 1 PSI = 1 lbƒ/in 2 = 6.89476 kPa.

Sometimes in the literature you can find the designation of the pressure unit lb/in 2 - this unit takes into account not lbƒ (pound-force), but lb (pound-mass). Therefore, in numerical terms, 1 lb/ in 2 is slightly different from 1 lbf/ in 2, since when determining 1 lbƒ it is taken into account: g = 9.80665 m/s 2 (at the latitude of London). 1 lb/in 2 = 0.454592 kg/(2.54 cm) 2 = 0.07046 kg/cm 2 = 7.046 kPa. Calculation of 1 lbƒ - see above. 1 lbf/in 2 = 4.44822 N/(2.54 cm) 2 = 4.44822 kg m/ (2.54 0.01 m) 2 s 2 = 6894.754 kg/ (m s 2) = 6894.754 Pa ≈ 6.895 kPa.

For practical calculations we can assume: 1 lbf/in 2 ≈ 1 lb/in 2 ≈ 7 kPa. But, in fact, equality is illegal, just like 1 lbƒ = 1 lb, 1 kgf = 1 kg. PSIg (psig) - same as PSI, but indicates gauge pressure; PSIa (psia) - the same as PSI, but emphasizes: absolute pressure; a - absolute, g - gauge (measure, size).

Water pressure

The SI unit of measurement is m.

• Head in feet (feet-head); 1 ft hd = 0.3048 m

Pressure loss during filtration

• PSI/ft - pounds (P) per square (S) inch (I)/foot (ft) - pounds per square inch/foot; 1 PSI/ft = 22.62 kPa per 1 m of filter layer.

SI unit of measurement - Joule(named after the English physicist J.P. Joule).

• 1 J - mechanical work of force 1 N when moving a body over a distance of 1 m.
• Newton (N) is the SI unit of force and weight; 1 Н is equal to the force imparting to a body weighing 1 kg an acceleration of 1 m 2 /s in the direction of the force. 1 J = 1 N m.

In heating engineering, they continue to use the abolished unit of measurement of the amount of heat - calorie (cal).

• 1 J (J) = 0.23885 cal. 1 kJ = 0.2388 kcal.
• 1 lbf ft (lbf) = 1.35582 J.
• 1 pdl ft (poundal feet) = 42.1401 mJ.
• 1 Btu (British Heat Unit) = 1.05506 kJ (1 kJ = 0.2388 kcal).
• 1 Therm (British large calorie) = 1 10 -5 Btu.

SI unit of measurement is Watt (W)- named after the English inventor J. Watt - mechanical power at which 1 J of work is performed in 1 s, or a heat flux equivalent to 1 W of mechanical power.

• 1 W (W) = 1 J/s = 0.859985 kcal/h (kcal / h).
• 1 lbf ft/s (lbf ft/s) = 1.33582 W.
• 1 lbf ft/min (lbf ft/min) = 22.597 mW.
• 1 lbf ft/h (lbf ft/h) = 376.616 µW.
• 1 pdl ft/s (poundal feet/s) = 42.1401 mW.
• 1 hp (British horsepower/s) = 745.7 W.
• 1 Btu/s (British Heat Unit/s) = 1055.06 W.
• 1 Btu/h (British Heat Unit/h) = 0.293067 W.

Surface heat flux density

The SI unit is W/m2.

• 1 W/m2 (W/m2) = 0.859985 kcal/(m2 h) (kcal/(m2 h)).
• 1 Btu/(ft 2 h) = 2.69 kcal/(m 2 h) = 3.1546 kW/m 2.

Dynamic viscosity (viscosity coefficient), η.

SI unit - Pa s. 1 Pa s = 1 N s/m2;
non-systemic unit - poise (P). 1 P = 1 dyne s/m 2 = 0.1 Pa s.

• Dina (dyn) - (from the Greek dynamic - strength). 1 dyne = 10 -5 N = 1 g cm/s 2 = 1.02 10 -6 kgf.
• 1 lbf h/ft 2 (lbf h/ft 2) = 172.369 kPa s.
• 1 lbf s / ft 2 (lbf s/ft 2) = 47.8803 Pa s.
• 1 pdl s / ft 2 (poundal-s/ft 2) = 1.48816 Pa s.
• 1 slug /(ft s) = 47.8803 Pa s. Slug (slug) is a technical unit of mass in the English system of measures.

Kinematic viscosity, ν.

Unit of measurement in SI - m 2 /s; The unit cm 2 /s is called “Stokes” (named after the English physicist and mathematician J. G. Stokes).

Kinematic and dynamic viscosity are related by the equality: ν = η / ρ, where ρ is density, g/cm 3 .

• 1 m 2 /s = Stokes / 104.
• 1 ft 2 /h (ft 2 /h) = 25.8064 mm 2 /s.
• 1 ft 2 /s (ft 2 /s) = 929.030 cm 2 /s.

The SI unit of magnetic field strength is A/m(Ammeter). Ampere (A) is the surname of the French physicist A.M. Ampere.

Previously, the Oersted unit (E) was used - named after the Danish physicist H.K. Oersted.
1 A/m (A/m, At/m) = 0.0125663 Oe (Oe)

The resistance to crushing and abrasion of mineral filter materials and, in general, of all minerals and rocks is indirectly determined using the Mohs scale (F. Mohs - German mineralogist).

In this scale, numbers in ascending order designate minerals arranged in such a way that each subsequent one is capable of leaving a scratch on the previous one. The extreme substances on the Mohs scale are talc (hardness unit 1, the softest) and diamond (10, the hardest).

• Hardness 1-2.5 (drawn with a fingernail): volskonkoite, vermiculite, halite, gypsum, glauconite, graphite, clay materials, pyrolusite, talc, etc.
• Hardness >2.5-4.5 (not drawn with a fingernail, but drawn with glass): anhydrite, aragonite, barite, glauconite, dolomite, calcite, magnesite, muscovite, siderite, chalcopyrite, chabazite, etc.
• Hardness >4.5-5.5 (not drawn with glass, but drawn with a steel knife): apatite, vernadite, nepheline, pyrolusite, chabazite, etc.
• Hardness >5.5-7.0 (not drawn with a steel knife, but drawn with quartz): vernadite, garnet, ilmenite, magnetite, pyrite, feldspars, etc.
• Hardness >7.0 (not marked with quartz): diamond, garnets, corundum, etc.

The hardness of minerals and rocks can also be determined using the Knoop scale (A. Knoop - German mineralogist). In this scale, values ​​are determined by the size of the imprint left on the mineral when a diamond pyramid is pressed into its sample under a certain load.

Ratios of indicators on the Mohs (M) and Knoop (K) scales:

SI unit of measurement - Bq(Becquerel, named after the French physicist A.A. Becquerel).

Bq (Bq) is a unit of activity of a nuclide in a radioactive source (isotope activity). 1 Bq is equal to the activity of a nuclide, at which one decay event occurs in 1 s.

Radioactivity concentration: Bq/m 3 or Bq/l.

Activity is the number of radioactive decays per unit time. The activity per unit mass is called specific.

• Curie (Ku, Ci, Cu) is a unit of activity of a nuclide in a radioactive source (isotope activity). 1 Ku is the activity of an isotope in which 3.7000 · 1010 decay events occur in 1 s. 1 Ku = 3.7000 · 1010 Bq.
• Rutherford (Рд, Rd) is an obsolete unit of activity of nuclides (isotopes) in radioactive sources, named after the English physicist E. Rutherford. 1 Rd = 1 106 Bq = 1/37000 Ci.

Radiation dose

Radiation dose is the energy of ionizing radiation absorbed by the irradiated substance and calculated per unit of its mass (absorbed dose). The dose accumulates over time of exposure. Dose rate ≡ Dose/time.

SI unit of absorbed dose - Gray (Gy, Gy). The extrasystemic unit is Rad, corresponding to the radiation energy of 100 erg absorbed by a substance weighing 1 g.

Erg (erg - from the Greek: ergon - work) is a unit of work and energy in the non-recommended GHS system.

• 1 erg = 10 -7 J = 1.02 10 -8 kgf m = 2.39 10 -8 cal = 2.78 10 -14 kW h.
• 1 rad = 10 -2 Gr.
• 1 rad (rad) = 100 erg/g = 0.01 Gy = 2.388 · 10 -6 cal/g = 10 -2 J/kg.

Kerma (abbreviated English: kinetic energy released in matter) - kinetic energy released in matter, measured in grays.

The equivalent dose is determined by comparing the nuclide radiation with X-ray radiation. The radiation quality factor (K) shows how many times the radiation hazard in the case of chronic human exposure (in relatively small doses) for a given type of radiation is greater than in the case of X-ray radiation at the same absorbed dose. For X-ray and γ-radiation K = 1. For all other types of radiation K is established according to radiobiological data.

Deq = Dpogl · K.

SI unit of absorbed dose - 1 Sv(Sievert) = 1 J/kg = 102 rem.

• BER (rem, ri - until 1963 was defined as the biological equivalent of an x-ray) - a unit of equivalent dose of ionizing radiation.
• X-ray (P, R) - unit of measurement, exposure dose of X-ray and γ-radiation. 1 P = 2.58 10 -4 C/kg.
• Coulomb (C) is an SI unit, amount of electricity, electric charge. 1 rem = 0.01 J/kg.

Equivalent dose rate - Sv/s.

Permeability of porous media (including rocks and minerals)

Darcy (D) - named after the French engineer A. Darcy, darsy (D) · 1 D = 1.01972 µm 2.

1 D is the permeability of such a porous medium, when filtering through a sample with an area of ​​1 cm 2, a thickness of 1 cm and a pressure drop of 0.1 MPa, the flow rate of a liquid with a viscosity of 1 cP is equal to 1 cm 3 /s.

Sizes of particles, grains (granules) of filter materials according to SI and standards of other countries

In the USA, Canada, Great Britain, Japan, France and Germany, grain sizes are estimated in meshes (eng. mesh - hole, cell, network), that is, by the number (number) of holes per inch of the finest sieve through which they can pass grains And the effective grain diameter is the hole size in microns. In recent years, US and UK mesh systems have been used more frequently.

The relationship between the units of measurement of grain sizes (granules) of filter materials according to SI and standards of other countries:

Mass fraction

Mass fraction shows what mass amount of a substance is contained in 100 parts by mass of a solution. Units of measurement: fractions of a unit; interest (%); ppm (‰); parts per million (ppm).

Solution concentration and solubility

The concentration of a solution must be distinguished from solubility - the concentration of a saturated solution, which is expressed by the mass amount of a substance in 100 parts by mass of a solvent (for example, g/100 g).

Volume concentration

Volume concentration is the mass amount of a dissolved substance in a certain volume of solution (for example: mg/l, g/m3).

Molar concentration

Molar concentration is the number of moles of a given substance dissolved in a certain volume of solution (mol/m3, mmol/l, µmol/ml).

Molal concentration

Molal concentration is the number of moles of a substance contained in 1000 g of solvent (mol/kg).

Normal solution

A solution is called normal if it contains one equivalent of a substance per unit volume, expressed in mass units: 1H = 1 mg eq/l = 1 mmol/l (indicating the equivalent of a specific substance).

Equivalent

The equivalent is equal to the ratio of the part of the mass of an element (substance) that adds or replaces one atomic mass of hydrogen or half the atomic mass of oxygen in a chemical compound to 1/12 of the mass of carbon 12. Thus, the equivalent of an acid is equal to its molecular weight, expressed in grams, divided by the basicity (the number of hydrogen ions); base equivalent - molecular weight divided by acidity (the number of hydrogen ions, and for inorganic bases - divided by the number of hydroxyl groups); salt equivalent - molecular weight divided by the sum of charges (valence of cations or anions); the equivalent of a compound participating in redox reactions is the quotient of the molecular weight of the compound divided by the number of electrons accepted (donated) by an atom of the reducing (oxidizing) element.

Relationships between units of measurement of the concentration of solutions
(Formula for transition from one expression of solution concentrations to another):

Accepted designations:

• ρ - solution density, g/cm 3 ;
• m is the molecular weight of the dissolved substance, g/mol;
• E is the equivalent mass of a solute, that is, the amount of substance in grams that interacts in a given reaction with one gram of hydrogen or corresponds to the transition of one electron.

According to GOST 8.417-2002 The unit of quantity of a substance is established: mole, multiples and submultiples ( kmol, mmol, µmol).

The SI unit of measurement for hardness is mmol/l; µmol/l.

In different countries, the abolished units for measuring water hardness often continue to be used:

• Russia and CIS countries - mEq/l, mcg-eq/l, g-eq/m 3 ;
• Germany, Austria, Denmark and some other countries of the Germanic group of languages ​​- 1 German degree - (Н° - Harte - hardness) ≡ 1 part CaO/100 thousand parts water ≡ 10 mg CaO/l ≡ 7.14 mg MgO/ l ≡ 17.9 mg CaCO 3 /l ≡ 28.9 mg Ca(HCO 3) 2 /l ≡ 15.1 mg MgCO 3 /l ≡ 0.357 mmol/l.
• 1 French degree ≡ 1 hour CaCO 3 /100 thousand parts water ≡ 10 mg CaCO 3 /l ≡ 5.2 mg CaO/l ≡ 0.2 mmol/l.
• 1 English degree ≡ 1 grain/1 gallon of water ≡ 1 part CaCO 3 /70 thousand parts water ≡ 0.0648 g CaCO 3 /4.546 l ≡ 100 mg CaCO3 /7 l ≡ 7.42 mg CaO/l ≡ 0.285 mmol /l. Sometimes the English degree of hardness is denoted Clark.
• 1 American degree ≡ 1 part CaCO 3 /1 million part water ≡ 1 mg CaCO 3 /l ≡ 0.52 mg CaO/l ≡ 0.02 mmol/l.

Here: part - part; the conversion of degrees into their corresponding amounts of CaO, MgO, CaCO 3, Ca(HCO 3) 2, MgCO 3 is shown as examples mainly for German degrees; Dimensions of degrees are tied to calcium-containing compounds, since calcium in the composition of hardness ions is usually 75-95%, in rare cases - 40-60%. Numbers are generally rounded to the second decimal place.

The relationship between units of water hardness:

1 mmol/l = 1 mg eq/l = 2.80°H (German degrees) = 5.00 French degrees = 3.51 English degrees = 50.04 American degrees.

A new unit of measurement of water hardness is the Russian degree of hardness - °Zh, defined as the concentration of an alkaline earth element (mainly Ca 2+ and Mg 2+), numerically equal to ½ its mole in mg/dm 3 (g/m 3).

Alkalinity units are mmol, µmol.

The SI unit of electrical conductivity is µS/cm.

The electrical conductivity of solutions and its inverse electrical resistance characterize the mineralization of solutions, but only the presence of ions. When measuring electrical conductivity, non-ionic organic substances, neutral suspended impurities, interference that distorts the results - gases, etc. cannot be taken into account. It is impossible by calculation to accurately find the correspondence between the values ​​of specific electrical conductivity and the dry residue or even the sum of all separately determined substances of the solution, since in In natural water, different ions have different electrical conductivity, which simultaneously depends on the salinity of the solution and its temperature. To establish such a dependence, it is necessary to experimentally establish the relationship between these quantities for each specific object several times a year.

• 1 µS/cm = 1 MΩ cm; 1 S/m = 1 Ohm m.

For pure solutions of sodium chloride (NaCl) in distillate, the approximate ratio is:

• 1 µS/cm ≈ 0.5 mg NaCl/l.

The same ratio (approximately), taking into account the above reservations, can be accepted for most natural waters with mineralization up to 500 mg/l (all salts are converted to NaCl).

When mineralization of natural water is 0.8-1.5 g/l, you can take:

• 1 µS/cm ≈ 0.65 mg salts/l,

and with mineralization - 3-5 g/l:

• 1 µS/cm ≈ 0.8 mg salts/l.

Content of suspended impurities in water, transparency and turbidity of water

Water turbidity is expressed in units:

• JTU (Jackson Turbidity Unit) - Jackson turbidity unit;
• FTU (Formasin Turbidity Unit, also designated EMF) - unit of turbidity for formazin;
• NTU (Nephelometric Turbidity Unit) - nephelometric turbidity unit.

It is impossible to give an exact ratio of turbidity units to suspended solids content. For each series of determinations, it is necessary to construct a calibration graph that allows you to determine the turbidity of the analyzed water in comparison with the control sample.

As a rough guide: 1 mg/l (suspended solids) ≡ 1-5 NTU units.

If the clouding mixture (diatomaceous earth) has a particle size of 325 mesh, then: 10 units. NTU ≡ 4 units JTU.

GOST 3351-74 and SanPiN 2.1.4.1074-01 equate to 1.5 units. NTU (or 1.5 mg/l for silica or kaolin) 2.6 units. FTU (EMF).

The relationship between font transparency and haze:

The relationship between transparency along the “cross” (in cm) and turbidity (in mg/l):

The SI unit of measurement is mg/l, g/m3, μg/l.

In the USA and some other countries, mineralization is expressed in relative units (sometimes in grains per gallon, gr/gal):

• ppm (parts per million) - part per million (1 · 10 -6) of a unit; sometimes ppm (parts per mille) also means a thousandth (1 · 10 -3) of a unit;
• ppb - (parts per billion) billionth (billionth) fraction (1 · 10 -9) of a unit;
• ppt - (parts per trillion) trillionth part (1 · 10 -12) of a unit;
• ‰ - ppm (also used in Russia) - thousandth (1 · 10 -3) of a unit.

The relationship between units of measurement of mineralization: 1 mg/l = 1ppm = 1 10 3 ppb = 1 10 6 ppt = 1 10 -3 ‰ = 1 10 -4%; 1 gr/gal = 17.1 ppm = 17.1 mg/l = 0.142 lb/1000 gal.

For measuring the salinity of salt waters, brines and salinity of condensates It is more correct to use units: mg/kg. In laboratories, water samples are measured by volume rather than by mass, so in most cases it is advisable to refer the amount of impurities to a liter. But for large or very small values ​​of mineralization the error will be sensitive.

According to SI, volume is measured in dm 3, but measurement is also allowed in liters, because 1 l = 1.000028 dm 3. Since 1964 1 l is equal to 1 dm 3 (exactly).

For salt waters and brines salinity units are sometimes used in degrees Baume(for mineralization >50 g/kg):

• 1°Be corresponds to a solution concentration equal to 1% in terms of NaCl.
• 1% NaCl = 10 g NaCl/kg.

Dry and calcined residue

Dry and calcined residues are measured in mg/l. The dry residue does not fully characterize the mineralization of the solution, since the conditions for its determination (boiling, drying the solid residue in an oven at a temperature of 102-110 ° C to constant weight) distort the result: in particular, part of the bicarbonates (conventionally accepted - half) decomposes and volatilizes in the form of CO 2.

Decimal multiples and submultiples of quantities

Decimal multiples and submultiple units of measurement of quantities, as well as their names and designations, should be formed using the factors and prefixes given in the table:

(based on materials from the site https://aqua-therm.ru/).

This guide has been compiled from various sources. But its creation was prompted by a small book from the Mass Radio Library, published in 1964, as a translation of O. Kroneger’s book in the GDR in 1961. Despite its antiquity, it is my reference book (along with several other reference books). I think time has no power over such books, because the fundamentals of physics, electrical and radio engineering (electronics) are unshakable and eternal.

Units of measurement of mechanical and thermal quantities.

The units of measurement of all other physical quantities can be defined and expressed through basic units of measurement. The units obtained in this way, in contrast to the basic ones, are called derivatives. To obtain a derived unit of measurement of any quantity, it is necessary to choose a formula that would express this quantity through other quantities already known to us, and assume that each of the known quantities included in the formula is equal to one unit of measurement. A number of mechanical quantities are listed below, formulas for their determination are given, and it is shown how the units of measurement of these quantities are determined. Unit of speed v- meter per second (m/sec) . Meter per second is the speed v of such uniform motion in which the body covers a path s equal to 1 m in time t = 1 second: 1v=1m/1sec=1m/sec Acceleration unit A - meters per second squared (m/sec 2). Meter per second squared - acceleration of such uniform motion, in which the speed changes by 1 m!sec in 1 second. Unit of force F - newton (And). Newton - the force that imparts an acceleration a equal to 1 m/sec 2 to a mass t of 1 kg: 1н=1 kg×1m/sec 2 =1(kg×m)/sec 2 Unit of work A and energy- joule (j). Joule -work done by a constant force F, equal to 1 n, on a path s in 1 m, traveled by a body under the influence of this force in a direction coinciding with the direction of the force: 1j=1n×1m=1n*m. Power unit W -watt (Tue). Watt - power at which work A equal to 1 J is performed in time t=-l sec: 1w=1j/1sec=1j/sec. Unit of heat quantity q - joule (j). This unit is determined from the equality: which expresses the equivalence of thermal and mechanical energy. Coefficient k taken equal to one: 1j=1×1j=1j Units of measurement of electromagnetic quantities Unit of electric current A - ampere (A). The force of an unchanging current, which, passing through two parallel straight conductors of infinite length and negligibly small circular cross-section, located at a distance of 1 m from each other in a vacuum, would cause between these conductors a force equal to 2 × 10 -7 newton. Unit of quantity of electricity (unit of electric charge) Q- pendant (To). Pendant - charge transferred through the cross-section of the conductor in 1 second at a current strength of 1 A: 1k=1a×1sec=1a×sec Unit of electrical potential difference (electrical voltage U, electromotive force E) - volt (V). Volt - the potential difference between two points of the electric field, when moving between them a charge Q of 1 k, work of 1 j is performed: 1v=1j/1k=1j/k Unit of electrical power R - watt (Tue): 1w=1v×1a=1v×a This unit is the same as the unit of mechanical power. Capacity unit WITH - farad (f). Farad - the capacitance of a conductor, the potential of which increases by 1 V if a charge of 1 k is applied to this conductor: 1f=1k/1v=1k/v Unit of electrical resistance R - ohm (ohm). - the resistance of a conductor through which a current of 1 A flows with a voltage at the ends of the conductor of 1 V: 1ohm=1v/1a=1v/a Unit of absolute dielectric constant ε- farad per meter (f/m). farad per meter - absolute dielectric constant of the dielectric, when filled with a flat capacitor with plates of area S of 1 m 2 each and a distance between the plates d~ 1 m acquires a capacity of 1 lb. Formula expressing the capacitance of a parallel-plate capacitor: From here 1f\m=(1f×1m)/1m 2 Unit of magnetic flux Ф and flux linkage ψ - volt second or weber (vb). Weber - magnetic flux, when it decreases to zero in 1 second in a circuit linked to this flux, e.m. appears. d.s. induction equal to 1 V. Faraday - Maxwell's law: E i =Δψ / Δt Where Ei- e. d.s. induction occurring in a closed loop; ΔW - change in magnetic flux coupled to the circuit during time Δ t : 1vb=1v*1sec=1v*sec Recall that for a single turn of the concept of flow Ф and flux linkage ψ match up. For a solenoid with the number of turns ω, through the cross section of which flow Ф flows, in the absence of dissipation, the flux linkage Unit of magnetic induction B - tesla (tl). Tesla - the induction of such a uniform magnetic field in which the magnetic flux φ through an area S of 1 m*, perpendicular to the direction of the field, is equal to 1 wb: 1tl = 1vb/1m 2 = 1vb/m 2 Unit of magnetic field strength N - ampere per meter (a!m). Ampere per meter - magnetic field strength created by a rectilinear infinitely long current with a force of 4 pa at a distance r = 2 m from the current-carrying conductor: 1a/m=4π a/2π * 2m Unit of inductance L and mutual inductance M - Henry (gn). - inductance of a circuit with which a magnetic flux of 1 Vb is connected, when a current of 1 A flows through the circuit: 1gn = (1v × 1sec)/1a = 1 (v×sec)/a Unit of magnetic permeability μ (mu) - henry per meter (g/m). Henry per meter - absolute magnetic permeability of a substance in which, at a magnetic field strength of 1 a/m magnetic induction is 1 tl: 1gn/m = 1vb/m 2 / 1a/m = 1vb/(a×m)

Relationships between units of magnetic quantities
in SGSM and SI systems

Non-system units

Some mathematical and physical concepts
used in radio engineering

Just like the concept of speed of movement, in mechanics and radio engineering there are similar concepts, such as the rate of change of current and voltage. They can be either averaged over the course of the process or instantaneous.

i= (I 1 -I 0)/(t 2 -t 1)=ΔI/Δt

When Δt -> 0, we obtain instantaneous values ​​of the rate of change of current. It most accurately characterizes the nature of the change in value and can be written as:

i=lim ΔI/Δt =dI/dt Δt->0

Moreover, you should pay attention - average values ​​and instantaneous values ​​can differ tens of times. This is especially clearly seen when a changing current flows through circuits with a sufficiently large inductance.

decibel

To evaluate the ratio of two quantities of the same dimension in radio engineering, a special unit is used - the decibel.

K u = U 2 / U 1 Voltage gain; K u[db] = 20 log U 2 / U 1 Voltage gain in decibels. Ki[db] = 20 log I 2 / I 1 Current gain in decibels. Kp[db] = 10 log P 2 / P 1 Power gain in decibels.

The logarithmic scale also allows you to depict functions with a dynamic range of parameter changes of several orders of magnitude on a graph of normal sizes.

To determine the signal strength in the reception area, another logarithmic unit of the DBM is used - dicibels per meter. Signal power at the receiving point in dbm:

P [dbm] = 10 log U 2 / R +30 = 10 log P + 30. [dbm];

The effective voltage across the load at a known P[dBm] can be determined by the formula:

Dimensional coefficients of basic physical quantities

Since 1963, in the USSR (GOST 9867-61 “International System of Units”), in order to unify units of measurement in all fields of science and technology, the international (international) system of units (SI, SI) has been recommended for practical use - this is a system of units of measurement of physical quantities , adopted by the XI General Conference on Weights and Measures in 1960. It is based on 6 basic units (length, mass, time, electric current, thermodynamic temperature and luminous intensity), as well as 2 additional units (plane angle, solid angle) ; all other units given in the table are their derivatives. The adoption of a unified international system of units for all countries is intended to eliminate the difficulties associated with the translation of numerical values ​​of physical quantities, as well as various constants from any one currently operating system (GHS, MKGSS, ISS A, etc.) into another.

Note. Multiple and submultiple units of measurement, with the exception of units of time and angle, are formed by multiplying them by the appropriate power of 10, and their names are added to the names of the units of measurement. It is not allowed to use two prefixes to the name of the unit. For example, you cannot write millimicrowatt (mmkW) or micromicrofarad (mmf), but you must write nanowatt (nw) or picofarad (pf). Prefixes should not be applied to the names of such units that indicate a multiple or submultiple unit of measurement (for example, micron). To express the duration of processes and designate calendar dates of events, the use of multiple units of time is allowed.

The most important units of the International System of Units (SI)

Basic units
(length, mass, temperature, time, electric current, light intensity)

Additional and derived units

Physical size is a physical property of a material object, process, physical phenomenon, characterized quantitatively.

Physical quantity value expressed by one or more numbers characterizing this physical quantity, indicating the unit of measurement.

The size of a physical quantity are the values ​​of numbers appearing in the value of a physical quantity.

Units of measurement of physical quantities.

Unit of measurement of physical quantity is a quantity of fixed size that is assigned a numerical value equal to one. It is used for the quantitative expression of physical quantities homogeneous with it. A system of units of physical quantities is a set of basic and derived units based on a certain system of quantities.

Only a few systems of units have become widespread. In most cases, many countries use the metric system.

Basic units.

Measure a physical quantity - means to compare it with another similar physical quantity taken as a unit.

The length of an object is compared with a unit of length, the mass of a body with a unit of weight, etc. But if one researcher measures the length in fathoms and another in feet, it will be difficult for them to compare the two values. Therefore, all physical quantities throughout the world are usually measured in the same units. In 1963, the International System of Units SI (System international - SI) was adopted.

For each physical quantity in the system of units there must be a corresponding unit of measurement. Standard units is its physical implementation.

The length standard is meter- the distance between two strokes applied on a specially shaped rod made of an alloy of platinum and iridium.

Standard time serves as the duration of any regularly repeating process, for which the movement of the Earth around the Sun is chosen: the Earth makes one revolution per year. But the unit of time is taken not to be a year, but give me a sec.

For a unit speed take the speed of such uniform rectilinear motion at which the body moves 1 m in 1 s.

A separate unit of measurement is used for area, volume, length, etc. Each unit is determined when choosing a particular standard. But the system of units is much more convenient if only a few units are selected as the main ones, and the rest are determined through the main ones. For example, if the unit of length is a meter, then the unit of area will be a square meter, volume will be a cubic meter, speed will be a meter per second, etc.

Basic units The physical quantities in the International System of Units (SI) are: meter (m), kilogram (kg), second (s), ampere (A), kelvin (K), candela (cd) and mole (mol).

There are also derived SI units that have their own names:

ANDmeasurements. To obtain an accurate, objective and easily reproducible description of a physical quantity, measurements are used. Without measurements, a physical quantity cannot be characterized quantitatively. Definitions such as “low” or “high” pressure, “low” or “high” temperature reflect only subjective opinions and do not contain comparisons with reference values. When measuring a physical quantity, a certain numerical value is assigned to it.

Measurements are carried out using measuring instruments. There are quite a large number of measuring instruments and devices, from the simplest to the most complex. For example, length is measured with a ruler or tape measure, temperature with a thermometer, width with calipers.

Measuring instruments are classified: by the method of presenting information (displaying or recording), by the method of measurement (direct action and comparison), by the form of presentation of readings (analog and digital), etc.

The following parameters are typical for measuring instruments:

Measuring range- the range of values ​​of the measured quantity for which the device is designed during its normal operation (with a given measurement accuracy).

Sensitivity threshold- the minimum (threshold) value of the measured value, distinguished by the device.

Sensitivity- connects the value of the measured parameter and the corresponding change in the instrument readings.

Accuracy- the ability of the device to indicate the true value of the measured indicator.

Stability- the ability of the device to maintain a given measurement accuracy for a certain time after calibration.