Used industrially to cross-link hydroxylic polymers, polyethyleneimine. Possesses some carcinogenic properties. Polyethyleneimine is a hygroscopic liquid used in paper manufacture to confer wet strength and in textiles, alkylated derivatives also form useful polymers.  [c.138]

The reaction is carried out in an alkaline medium, usually potassium hydroxide with some lithium hydroxide. On charging, the Fe(OH)2 is reduced to Fe and the Ni(OH)2 oxidized to nickel(III) oxide. Its discharge-voltage is only about 1 -2 V, and as compared with the lead accumulator it has a rather low current efficiency and is rather more expensive. It has some compensating advantages in lower weight and greater mechanical strength, for the electrode materials are compressed into perforated pockets of nickel-plated steel, and the accumulator can therefore withstand mechanical shocks and high rates of charge or discharge.  [c.273]

Spirits are described as so many degrees over proof (OP) or under proof (UP). Sometimes, for alcoholic liquors, spirit strength is given in degrees proof, e.g. proof spirit is 100° proof and 70° proof 30° under proof (i.e. a solution eontaining 70% of proof spirit).  [c.328]

Pyrex A trade name for a heat-resisting boro-silicate glass containing a high percentage of SiOj with some B, Al and alkalis. Pyrex has high mechanical strength, resists attacks by strong acids and alkalis, and withstands  [c.334]

The basic procedure is to increase the compression ratio of the CFR engine just to the point of obtaining a standard knocking intensity indicated by a pressure detector in the combustion chamber. The critical compression ratio thus recorded is bracketed by two values taken along with two binary heptane-isooctane of neighboring compositions. For each operation, the fuel-air ratio is taken to be that corresponding to the strongest tendency to knock. The octane number is calculated by linear interpolation determining the primary reference mixture having similar behavior as the fuel being tested.  [c.196]

Standards are generally not made into law and therefore are not enforced but depend on voluntary compliance. Their only strength lies in the consensus obtained during their preparation. There are, nevertheless, a few exceptions it can happen that a decree or directive gives a standard an obligatory nature.  [c.294]

If we consider a well trajectory from surface to total depth (TD) it is sensible to look at the shallow section and the intermediate and reservoir intervals separately. The shallow section, usually referred to as top hole consists of rather unconsolidated sediments, hence the formation strength is low and drilling parameters and equipment have to be selected accordingly.  [c.44]

A low strength formation in which open fractures are initiated by too high mud pressure in the borehole  [c.59]

The recovery factor (RF) is in the range 30-70%, depending on the strength of the natural aquifer, or the efficiency with which the injected water sweeps the oil. The high RF is an incentive for water injection into reservoirs which lack natural water drive.  [c.192]

In the open hole DST, inflatable packers are set against the open hole section to straddle the prospective interval. Migration of hydrocarbons into the annulus is prevented by the upper packer, and a good seal is required to ensure safety. Therefore the open hole DST can only be run where the open hole section is in gauge. The safe length of the open hole test section would be determined by the strength of the casing shoe. If several intervals are to be tested independently, then a oased hole DST may be considered. Only the interval of interest is perforated and allowed to flow. All other intervals remain isolated behind casing. Each interval is sealed off prior to testing another. In both types of DST it is possible to run a downhole pressure gauge, and therefore to perform a drawdown and build-up survey.  [c.224]

A Magnetic Method for Testing of High Strength Bolts.  [c.3]

A new, non destructive method has been developed for testing high strength bolts which is based on measuring the magnetic stress on the head of a bolt. The forces originating in the body of the bolt can be determined in this way since these forces are proportional to the stress state in the head of the bolt.  [c.3]

The utilization of high strength bolts in the construction of bridges has spread during the past 20-25 years. Official regulations concerned with checking the state of bridges require periodic examination of the condition of these bolts as well. Such examinations - in accordance with the relevant DIN standard - are based on the correlation between the degrees of further swivelling of the nut and the applied torque Based on experience the following objections can be raised against this method  [c.3]

The strength of an acid is measured by the value of its dissociation constant, strong acids, e.g. HCl, HNO3. being substantially fully ionized in solution and weak acids predominately unionized.  [c.12]

Strong acids completely hydrolyse cellulose to glucose very mild hydrolysis gives hydrocelluloses with shorter chains and lower viscosity and tensile strength. Under special conditions a large yield of cellobiose is obtained.  [c.86]

It is used instead of phthalic anhydride in the preparation of certain eosin dyes (phlox-ines, etc.) which are bluer and brighter than those from unchlorinated intermediates, tetracyanoethylene, TCNE, (NC)2C C(CN)j. A sublimable white crystalline solid, smelling of hydrogen cyanide, m.p. 200" C, which has high thermal and oxidative stability. Reacts with most compounds containing an active hydrogen and with dienes in typical Diels-Alder additions. It is probably the strongest r-acid known it forms a series of coloured complexes with aromatic hydrocarbons and gives salts of the radical anion with many metals, e.g. K TCNE . 7,7,8, tetracyanoquinonedimetfaaDe, TCNQ NC /= CN  [c.389]

One knows that molecular structures have vibrational states, associated with electron levels in the UV region, which are quantified that is, which can give only discrete values. If a molecular oscillator such as the carbonyl group C = 0 in a ketone is subjected to an electromagnetic beam having an energy of E = hv exactly equal to the resonant frequency, the energy will be absorbed and the oscillator passes into an excited state of vibration. The corresponding energy region is that of the infrared. These vibrations depend on the nature of the atoms making up the molecule and the strength of the bonds between them. For example, if two atoms of mass m and m2 are held together by a bond whose force constant is fe, the vibration frequency v will be as followsO )  [c.56]

The chemistry of cement slurries is complex. Additives will be used to ensure the slurry remains pumpable long enough at the prevailing downhole pressures and temperatures but sets (hardens) quickly enough to avoid unnecessary delays in the drilling of the next hole section. The cement also has to attain sufficient compressive strength to withstand the forces exerted by the formation over time. A spacer fluid is often pumped ahead of the slurry to clean the borehole of mudcake and thereby achieve a better cement bond between formation and cement.  [c.56]

The volumetries of a field, along with the anticipated recovery factors, control the reserves in the field those hydrocarbons which will be produced in the future. The value of an oil or gas company lies predominantly in its hydrocarbon reserves which are used by shareholders and investors as one indication of the strength of the company, both at present and in the future. A reliable estimate of the reserves of a company is therefore important to the current value as well as the longer term prospects of an oil or gas company.  [c.153]

See pages that mention the term Strength : [c.37]    [c.280]    [c.312]    [c.23]    [c.24]    [c.24]    [c.80]    [c.83]    [c.85]    [c.87]    [c.87]    [c.106]    [c.126]    [c.152]    [c.174]    [c.175]    [c.190]    [c.200]    [c.210]    [c.220]    [c.239]    [c.246]    [c.247]    [c.271]    [c.318]    [c.320]    [c.328]    [c.347]    [c.373]    [c.387]    [c.400]    [c.427]   
Engineering materials Ч.2 (1999) -- [ c.0 ]

Carbon materials for advanced technologies (1999) -- [ c.134 , c.144 , c.153 , c.157 , c.176 , c.190 , c.406 , c.436 , c.471 , c.508 , c.525 ]

Plastics engineering Изд.3 (2002) -- [ c.18 , c.37 , c.173 , c.232 ]

Solids under high-pressure shock compression - mechanics, physics, and chemistry (1992) -- [ c.0 ]

Mechanics of composite materials (1999) -- [ c.2 , c.26 , c.27 , c.28 , c.29 , c.30 , c.390 , c.398 , c.423 ]

Machanics of composite materials (1998) -- [ c.2 , c.26 , c.27 , c.28 , c.29 , c.30 , c.390 , c.398 , c.423 ]