05.07.2009

When mining an economic seam such as metal ores or coal, this is normally the rock left on the roof of the mine gallery

The concept is to charge a very high tariff during these peak hours in return for a reduction in tariff during the remainder of the year. The objective is to provide incentives to high consumers to cut down either partly or completely their electricity consumption from the grid during peak consumption hours.

For instance, rolling peak schemes prescribe for time of use consumers a particularly high tariff for 100 hours a year in which demand is particularly high and, in consideration, the consumers in this arrangement enjoy reduced time of use tariff during other peak and shoulder clusters

Intentionally engineered electrical power outage caused due to lack of available resources (electricity) to meet demand during peak hours.

The arrangement is meant for large electricity consumers such as factories, kibbutzim, hotels and governmental offices that agree to cut themselves off from the grid during peak consumption hours – and use private generators – in order to cut the load from the grid. These consumers undertake to activate their generators during certain hours (up to 100 hours per year) in return for a financial incentive for each KwH not consumed. The objective of the arrangement is to reduce hundreds of megawatts of consumption during peak hours in order to help cope with the emergency situation in Israel’s electricity economy. In November 2009, the PUA passed new regulations regarding rolling blackout arrangements according to which IEC is entitled to cut off large consumers for longer periods than agreed in the arrangement but must compensate them with even lower tariff

The Rockwell Hardness test is a hardness measurement based on the net increase in depth of impression as a load is applied. Hardness has been variously defined as resistance to local penetration, scratching, machining, wear or abrasion, and yielding. The multiplicity of definitions, and corresponding multiplicity of hardness measuring instruments, together with the lack of a fundamental definition, indicates that hardness may not be a fundamental property of a material, but rather a composite one including yield strength, work hardening, true tensile strength, modulus of elasticity, and others. The Rockwell hardness test method consists of indenting the test material with a diamond cone or hardened steel ball indenter