Plant liquid nitrogen

I do not know of any case in which delivery of liquid oxygen instead of liquid nitrogen caused an explosion. But, as stated in Section 12.3.1. in one case the nitrogen was used to inert a catalyst bed. and the catalyst got hot in another case a high-oxygen-concentration alarm in the plant sounded, and in several cases check analyses showed that oxygen had been supplied. 

The general method is to drive in a ring of vertical pipes and pass chilled brine down through an inner pipe so that it flows up the annulus, to cool and eventually freeze the surrounding wet soil. This process is continued until the ice builds up a continuous wall around the proposed excavation. Depths of over 650 m have been excavated in this way. Calcium chloride brine, cooled by surface plant, is usual, but liquid nitrogen has been used on small shafts [50]. 

Liquid nitrogen is obtained from air in large liquefaction and separation plants. 

Possible contamination by chemical or biological substances is one of the most important concerns when producing pharmaceutical proteins. Plant cell cultures ensure the production of the desired protein in a controlled, sterile and sealed environment and can be adapted to cGMP conditions. Therefore, the risk of contamination is minimized and the production conditions can be modified more easily in a contained reactor than in the field. Another advantage is the ability to freeze plant suspension cells in liquid nitrogen [66, 67] so that master and working cell banks can be established, a prerequisite for cGMP procedures [68]. 

This technique is simple in basic principle. Material is first rapidly frozen to the temperature of liquid nitrogen. It is then fractured, cryo-planed to produce a flat surface for analysis, and transferred to the cryo-stage of an SEM. It is analyzed while still frozen, and thus ion movement during tissue preparation should be minimal. A more detailed scheme of a typical procedure (45,46) is given in Subheading 3.4.2.1. This is undoubtedly the most popular microanalytical method with plant scientists at present, and as Table 1 shows it has been applied to a wide range of tissues and research topics (46-53). Recent developments include a... 

The ideal solution to microanalysis would be simply to freeze the plant material rapidly to the temperature of liquid nitrogen and then section it while it is still frozen on a cryotome. The frozen sections would then be transferred to a cold stage in a TEM and analyzed. In theory, no ion movement will take place and analysis at the high resolution of TEM should be possible. Indeed, this is a useful technique for liver, kidney, and soft animal tissues, but unfortunately it is almost impossible to cut tough plant material, and maintain the sections in a reasonable state for analysis (2). Even if this problem could be overcome unstained tissues will be difficult to visualize in TEM. 

The consumption of power in this process is theo-etically very small, as much carbon monoxide should e liquefied in the coil in the vessel B as is volatilised lutside it (this is theoretically true when the pressure )f the gas passing through the coil is atmospheric) Towever, in practice, the necessity for power consump-lon arises from the fact that liquid nitrogen must )e continuously supplied to the vessel D in order to jrevent the temperature of the plant rising from ex-ernal infiltration of heat, which takes place in spite of he most effective lagging. 

Purification of Synthesis Gas. This involves the removal of carbon oxides to prevent poisoning of the NIT3 catalyst. An absorption process is used to remove the bulk of the C02, followed by methanation of the residual carbon oxides in the methanator, Modern ammonia plants use a variety of C02-removal processes with effective absorbent solutions. The principal absorbent solutions currently in use are hot carbonates and cthanolamincs. Other solutions used include methanol, acetone, liquid nitrogen, glycols, and other organic solvents. 

Freeze 50 g plant material with liquid nitrogen in a separate container of Teflon, stainless steel, or other material that can withstand temperatures of-210°C. 

Grinding the plant material in the presence of liquid nitrogen provides a uniform powdered composite sample however, some powdered materials are very hygroscopic. With such materials, it is advisable to accurately weigh the plant material (before freezing) and quantitatively transfer the powdered material with an appropriate solvent. 

Make sure that the container is completely dried before pouring the liquid nitrogen into the blender because any remaining water will freeze the blender bearings, and the blades will not revolve. If this happens, recover the material and rinse the blender with acetone and air dry. Chill the blender with small amounts of liquid nitrogen, allow to evaporate, and turn the blender on and off before adding frozen plant material. 

Willemer, H. Freeze-drying plants with modem refrigerants including liquid nitrogen. 1st. World Meeting of... 

As recently as 1960, commercial thermography was very limited for plant operations. An instrument that weighed 85 pounds, required 110 volt power supply, and was cooled by liquid nitrogen was the best equipment to produce a useful thermal picture. [13]... 

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