Liquid nitrogen injection

Since beverage cans, particularly two-piece cans, are made with very thin side walls, their ability to resist vertical top loads is limited. It is not until they have been filled with carbonated product and the product has reached room temperature that cans achieve full top-load strength. For non-carbonated products this can be a problem however, there are systems available which can inject a precise volume of liquid nitrogen into a filled can, just before the end is seamed on to the can body. As the liquid converts to a gaseous state, it expands. This helps to expel excess oxygen from the headspace, which may otherwise affect shelf life, and provides the internal pressure required for side-wall strength and package stability. 

By adjustment of the injection time and duration, PET bottles too can be pressurised in this way when they are used for non-carbonated products. The advantage of nitrogen is that the gas does not go into solution with the product to change a still product into a fizzy drink. 

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Direct injection of liquid nitrogen is also used on the larger vehicles. This is carried in metal vacuum flasks and the vehicle will he reliant on depots where the liquid nitrogen flask can he refilled. The only mechanical equipment will he a thermostatically controlled solenoid injection valve. 

The JC-enriched butadiene samples were transferred and sealed in nmr tubes, along with the solvent and initiator, under a vacuum of about 10 torr. They were held at liquid nitrogen temperatures before warming to the reaction temperature. The non-enriched butadiene monomer was syringed from a hydrocarbon solution and injected through a rubber septum into an nmr tube containing solvent and initiator at liquid nitrogen temperature. The tube was then sealed under vacuum. 

One of the key developments in the development of thermal desorption devices was the possibility for cryofocusing systems that have the advantage of injection-like samples. A short section of capillary tubing at liquid nitrogen temperatures (i.e., -160°C) traps the volatiles. When capillary columns replaced packed columns as the standard, complete flow from the desorption trap (5 ml/min minimum) to the capillary columns ( 1 ml/min) was possible through the use of cryofocusing. The split injection interface was another development that splits the flow so that only a part of the desorbed volatiles entered the column. While this allowed the need for cryofocusing to be circumvented, sensitivity was lost due to the split. 

Bis[phenyltelluro]propane2 (Tellurium Insertion) A suspension of 12.8 g (0.1 mol) of tellurium powder in 100 ml tetrahydrofuran is frozen in a liquid nitrogen bath. 55.6 ml of a 1.8 molar solution of phenyl lithium (0.1 mol) in cyclohexane/dielhyl ether are injected. The mixture is allowed to thaw and is then stirred for 0.5 h at 20°. The mixture is then frozen again. 10.1 g (0.05 mol) of 1,3-dibromopropane are added, the mixture is allowed to thaw, magnetically stirred at 20° for 1 h, then hydrolyzed with 100 ml of an aqueous sodium chloride solution. The organic phase is separated, the aqueous phase extracted several times with... 

Anaesthetized mice (female, SKH-1, from Simonsen, injected intraperitoneally with sodium pentobarbital, 50 mg/kg body weight) were irradiated on one flank with light from the solar simulator. Mice were killed by cervical dislocation immediately after irradiation, and irradiated skin as well as control, non-irradiated skin from the contralateral flank were removed. Adhering fat and subcutis were gently scraped free and the samples were frozen in liquid nitrogen. 

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