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The FBISE was established under the FBISE Act 1975. [2] It is an autonomous body of working under the Ministry of Federal Education and Professional Training. [3] The official website of FBISE was launched on June 7, 2001, and was inaugurated by Mrs. Zobaida Jalal, the Minister for Education [4] The first-ever online result of FBISE was announced on 18 August 2001. [5]
Commercial refrigeration. Refrigeration is any of various types of cooling of a space, substance, or system to lower and/or maintain its temperature below the ambient one (while the removed heat is ejected to a place of higher temperature). [1] [2] Refrigeration is an artificial, or human-made, cooling method. [1] [2]
Below 10 K one uses magnetic materials which are specially developed for this application. The so-called coefficient of performance (COP; denoted ξ {\displaystyle \xi } ) of coolers is defined as the ratio between the cooling power Q ˙ L {\displaystyle {\dot {Q}}_{\text{L}}} and the compressor power P .
Adsorption refrigeration has been extensively researched in recent years because the technology is often noiseless, non-corrosive and environmentally friendly. [5] The heat source for adsorption refrigeration can be fossil fuel , biomass fuel , nuclear fission , geothermal energy , waste heat , or solar thermal energy .
The refrigeration process uses a mixture of two isotopes of helium: helium-3 and helium-4. When cooled below approximately 870 millikelvins , the mixture undergoes spontaneous phase separation to form a 3 He-rich phase (the concentrated phase) and a 3 He-poor phase (the dilute phase).
A cascade refrigeration cycle is a multi-stage thermodynamic cycle. An example two-stage process is shown at right. (Bottom on mobile) The cascade cycle is often employed for devices such as ULT freezers. [1] In a cascade refrigeration system, two or more vapor-compression cycles with different refrigerants are used.
An enhanced electronic version, known as ASHRAE Handbook Online is a web-based version updated annually that contains the four latest volumes as well as extra content such as calculations, demonstration videos, and spreadsheets. The various versions of the Handbook are typically available to the public via technical, and other, libraries and ...
A pot-in-pot refrigerator, clay pot cooler [1] or zeer (Arabic: زير) is an evaporative cooling refrigeration device which does not use electricity. It uses a porous outer clay pot (lined with wet sand) containing an inner pot (which can be glazed to prevent penetration by the liquid) within which the food is placed.