Cooling in situ

Headspace SPME Routine Heating/cooling In situ chemical derivatization Volatile and semivolatile compounds Volatile and semivolatile compounds with small partition coefficients Polar compounds Any... 

In some experiments the cell, being connected to a gas flow system via long capillaries, was taken out from the low-temperature spectrometer resonator, placed in a high-temperature furnace, calcined in a gas stream, placed back in the resonator, cooled in-situ under gas flow and the ESR spectra were taken at 120"K. 

When the heating cycle is complete the mould is either cooled in situ with water sprays or moved by block and tackle to a second rocking bed for cooling so that the first machine can immediately be re-loaded with a second mould. The operator can control the direction and speed of rotation of the mould in order to achieve optimum results, and several experimental cycles are often necessary before a satisfactory product can be made. The wall thickness of the product tends to be greatest in the hottest areas of the mould. It may even be necessary to attach an insulating material such as glass fibre to certain outer areas of the mould to achieve the desired heat distribution. Similarly, it may be necessary to preheat certain detailed areas of the mould, such as rims and valve areas, with a gas flame prior to moulding to obtain a sufficient thickness. 

X ranges from -i-10°C for glasses which do not devitrify during a standard DTA or DSC run (e.g. silica glass) to —20°C for those with a small Hruby parameter. For an insulated, resistance-heated annealing furnace. Step (c) is simply achieved by switching the furnace off and allowing the sample to cool in situ. 

Several commercial grades are available fine crystals of 99 to 100% purity, large crystals, pressed lumps, rods, and granular material. Double-Decomposition Methods. Double-decomposition processes all iavolve the reaction of sodium chloride, the cheapest chlorine source, with an ammonium salt. The latter may be suppHed directiy, or generated in situ by the reaction of ammonia and a supplementary iagredient. Ammonium chloride and a sodium salt are formed. The sodium salt is typically less soluble and is separated at higher temperatures ammonium chloride is recovered from the filtrate by cooling. 

It is liquefied by conducting the gas through a condenser cooled with ice water. Where difficult to obtain, it may be prepared by passing chlorine gas through a stirred suspension of sodium tetrakis(cyano-C)zincate prepared in situ from sodium cyanide and zinc sulfate. ... 

In 10 ml of ethanol was dissolved with heating 200 mg of 2-methyl-6-(1-methoxy-2-carba-moyloxyethyl)-1,4-benzoquinone and the resulting solution was cooled. To the cooled solution was added 0.5 ml of aziridine and then the resulting mixture was allowed to stand In a refrigerator at 5°C to 8°C for 4 days. Thereafter, the crystalline substance which precipitated in situ was recovered by filtration and washed with ethanol to give 50 mg of the desired product as red crystals melting at 200°C (with decomposition). 

According to these experiments there were three processing temperature regions with three different morphologies, At high temperatures both the PP and the LCP were molten, and in situ fibrillation of the LCP component took place during cooling of the oriented... 

At lower temperatures (180-200°C) the material was processed without melting the LCP and a real composite structure with solid LCP fibers in the PP matrix was formed. When processing was done above the Tm of the LCP (280°C), all the material was molten during processing and a compositelike blend morphology was created in situ during cooling of the oriented melt phase. 

Miscellaneous There are many interesting applications that arise from time to time that are outside the main stream of industry described above. Examples include desalination plant reactor cooling water circuits automobile body corrosion in situ) marine (vessels, piling, harbour installations) aircraft (in situ) packaging and cavitation monitoring. 

Fig. 8.5 Sections of [in situ) X-ray powder patterns of a-Ca3(BN2)2 with the 220 reflection and -Ca3(BN2)2 with 200, 224, and 400 reflections. (Low-temperature) y -Ca3(BN2)2 is obtained on slow cooling...

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