Jacking

Drilling Jackets are small steel platform structures which are used in areas of shallow and calm water. A number of wells may be drilled from one jacket. If a jacket is too small to accommodate a drilling operation, a jack-up rig (see below) is usually cantilevered over the jacket and the operation carried out from there. Once a viable development has been proven It is extremely cost effective to build and operate jackets in a shallow... 

Semi-submersible rigs are often referred to as semis , and are a floating type of rig. Like the jack-up, a semi is self contained. The structure is supported by large pontoons which are ballasted with water to provide the required stability and height. The rig is held in position by anchors and mooring lines or dynamically positioned by thrusters. A large diameter steel pipe ( riser ) is connected to the sea-bed and serves as a conduit for the drill string. The blowout preventer (BOP) is also located at the sea-bed ( sub sea stack ). 

Semis are often used in water depths too deep for jack-ups. However, anehor handling and the length of the riser eventually impose a limit on the operating depth. Their stability makes them suitable vessels for hostile offshore environments. 

Particularly for jack-up rigs, site surveys may have to be carried out prior to each reemployment to ensure that the rig is positioned away from the previously formed footprints (depressions on the sea-bed left by the jack-up legs on a previous job). 

Dr. Jack Collins. Molecular Research Institute. Palo Alto. CA. 

Jack A and M Levitt 1978. Refinement of Large Structures by Simultaneous Minimization of Energy and R-factor. Acta Crystallographica A34 931-929. 

Ltease test. The enzyme uretwe hydrolyses urea to ammonium carbonate (p. 519). The reaction is sp ific and is frequently used for solu tions of urea to which the biuret test cannot be applied. Add about 5 drops of phenohred to o 2 g. of urea dissolved in 5 ml. of water. To this yellow solution, add 0 2 g. of jack bean meal suspended in 2 ml. of water containing. also 5 drops of phenol-red. The colour changes to red as the solution becomes alkaline. 

Urease soya bean, jack bean urea ammonium carbonate 7-2-7 9... 

The chief sources of this important enzyme are (a) the jack bean (Canavalia ensiformis). (b) the soy (or soja) bean (Glycine hispida). The enzyme is of great value in identifying and estimating urea. The action of urease on urea is specific, the reaction catalysed being ... 

Urease is one of the enzymes which have been obtained in the crystalline state. This has been done by stirring jack bean meal with 30°o aqueous acetone, filtering and allowing the filtrate to remain at o for several hours. The urease which crystallises out is separated by centrifuging and is then recrystallised. Like crystalline pepsin and trypsin, it is a protein. 

Place about 0 2 g. of jack-bean meal in a test-tube, add 2 ml. of water and about 5 drops of phenol-red. Mix thoroughly and allow the faintly yellow solution to stand while the urea solution is being made up. 

Urease solution. Place about 5 g. of jack-bean meal in a mortar and grind up with about 10 ml. of water, t hen add about 90 ml. of water, mix thoroughly and allow to stand for some time in order to deposit starch and other insoluble substances. Decant off the supernatant liquid into a conical flask and cork the latter. 

Underwriters Laboratories 333 Pfingsten Road Northbrook, Id. 60062 Standards for Safety is ahst of more than 200 standards that provide specifications and requirements for constmetion and performance under test and in actual use of a broad range of electrical apparatus and equipment, including household appHances, fire-extinguishing and fire protection devices and equipment, and many other nongenerady classifiable items, eg, ladders, sweeping compounds, waste cans, and roof jacks for trader coaches. 

Lake states jack pine and red pine white pine and tamarack red oak, aspen, and maple birch... 

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