Minimum mass of air that would be crossed by solar radiation if the star was in the zenith, for a facility located at sea level, in the case of clear sky (standard conditions). Note: The mass of air actually crossed varies depending on the inverse sine of the height of the Sun (see Height of the Sun) and increases as a function of the atmospheric turbidity.

Level of the upstream water plane, indicating the point where it is measured.

The ampere is the intensity of a constant current which, held in two parallel, rectilinear conductors of infinite length, of negligible circular cross-section and placed at a distance of 1 m from each other in the void, would produce between these conductors a force equal to 2 x 10 -7 N per meter in length. [CIPM (1946), Resolution 2 adopted by the 9th CGPM [(1948)].

Fixing of tethers or bolts in holes made through the layers adjacent to excavations for the purpose of supporting them. The risers may be roof, sill or stem, depending on their location.

Energy that, under certain thermodynamic conditions, is not convertible into another form of energy.

Angle between the line connecting the center of the solar disk to the observation point and the normal to the plane of observation. Note: The point of the celestial sphere defined by the normal plane of observation is called zenith.

In addition to the known numbers of their production, geological, technical or economic parameters will vary over time the reserve values of a reservoir. Both the development work and a better knowledge of the deposit or the implementation of new technical means generally increase us. A tax or contractual change, or a change in market prices, may cause them to decrease or increase. Moreover, the values announced by a company or a state can be very conservative or, on the contrary, very optimistic, depending on the objective (economic, political or financial).

The average change over the last twelve months compares the level of the average price index of the last twelve months with the immediately previous twelve months. Because it is a moving average, this rate of change is less sensitive to sporadic changes in prices. The value obtained in December has been used as a reference in the social concertation plan, and is therefore associated with the annual inflation rate

Storage in which the reservoir has an annual filling and emptying cycle.

Relation between the average annual load of an energy system and the maximum load of the system throughout the year. It is expressed in percentage and can be used in forecasting variations in consumption. In order to take into account climatic variations, when comparing one year with another, the actual load factor can be corrected to take account of average climatic conditions.

The American Petroleum Institute (API) has adopted a scale to measure the density of crude oils and petroleum products, expressed in degrees: API ° = (141.5 / g) -131.5 where g is the oil density at 60 ° F.

Product (at effective values) of the current by electromotive force or voltage, regardless of phase relationship between voltage and current.
Note: It is an important feature in the design of an electrical equipment.

Mass of volume unit occupied by bulk fuel; the conditions under which the measurement is made must be indicated.

Combustion wastes from the mineral impurities contained in the fuel; May also contain unburned fuel.

Combustion residues obtained when the fuel is calcined at a temperature of 815 ° C under certain conditions.

Solid residue resulting from the burning of fuel caused by mineral impurities contained therein. It may also contain unburned fuel. The fly ash, of fine granulometry, is dragged by the combustion gases. Coarse-grained slag accumulates at the bottom of the combustion chamber.

Proportion of certain ash elements, expressed as oxides and acid residues. Ash testing is generally limited to the determination of silicon, aluminum, iron, calcium, magnesium, potassium, sodium, titanium, phosphorus and sulfur.

Voltage between phases whose effective value is greater than 45 kV and equal to or less than 110 kV.

Transformer substation between high and low voltage networks.

There are a number of physical processes associated with biomass conversion technologies for their prior conditioning: compaction, granulation, grinding, densification, etc., drying, pressing or filtering, to reduce the high initial water content or to recover the Products obtained (eg drilling of manure fields in which deep layers form methane by in situ fermentation, distillation, decantation and other product separation processes).