LN2 = liquid nitrogen

A toI heat transfer coefficient from the heating medium to the sublimation front s LN2 liquid nitrogen... 

LC Level controller LDV Let down valve LHV Lower heating value LH2 or LH2 Liquid hydrogen LN2 or LN2 Liquid nitrogen LNG Liquefied natural gas LSH High level switch LP Low pressure LT Level transmitter... 

FI = front illuminated BI = back illuminated BI-UV = back illuminated, UV enhanced. LN2 = liquid nitrogen cooling TE = thermoelectric cooling. 

A precooling of dewar with liquid nitrogen (LN2) from 300 to 77 K saves a large amount of LHe liquid N2 has a vaporization heat 60 times that of LHe and a cost 20 times less. Moreover, the enthalpy of materials (es. A1) between 77 and 300 K (162 J/g) is much higher than that between 4 and 77 K (9 J/g). 

Partial pressure of those vapors which can be liquefied at the temperature of liquid nitrogen (LN2). 

The freezing of a slice of beef in direct contact with a model liquid has been used to demonstrate the influence of the two terms w and u. To freeze a product for freeze-drying, two methods are mainly used (i) freezing of the product in trays or in vials on cooled surfaces or (ii) in a flow of cold air. If these methods do not result in a sufficient freezing rate, liquid nitrogen (LN2) in direct contact with the vials is used (see Figures 2.2.1 and 2.2.2) or droplets of the product are sprayed into LN2 (see Section 2.1.4). 

Fig. 1.73.3. DR as a function of drying time of 10% mannitol solution frozen in LN2 in 130 vials. Plot 1 product is collapsed because 380 vials have been loaded (also confirmed by visual inspection of the dry product) after a short time ofSD, the water evaporates with difficulty from the highly viscous concentrates. Plot 3 in liquid nitrogen frozen at a rate of 30-60 °C/min, below DR = 0.3%/h the unfrozen water in viscous inclusions is difficult...

Cooling of the shelf heat transfer system and of the condenser is effected by compressor cooling systems. Nowadays cooling with liquid nitrogen (LN2) is being carried out more and more. 

Fig. 2.31. LN2 evaporator plate - cross-section. The cross-sections of the channels from the liquid nitrogen inlet to the gaseous nitrogen outlet are increasing considering the expansion of the gas.

The evaporation of liquid nitrogen (LN2) in HE-1 brings down the H2 temperature below its inversion point. In the process of liquefaction, one must consider this inversion point temperature (-5°C, or -95°F), because the behavior of H2 changes (reverses) at this point. Below the inversion temperature, when the pressure is reduced, the temperature of H2 will drop. Above that temperature the opposite occurs a drop in pressure causes a rise in temperature. 

R. Cully, Refrigerants, the environment and the liquid nitrogen option. International Society of Pharmaceutical Engineering (ISPE), Antwerpen, 1994. AMSCO-Finn-Aqua Product Information Condenser with LN2 Cooler FA 00.20.02./ 10.91. 

Work with disposable gloves. 3-5g of flies are ground in liquid nitrogen (LN2) with porcelane mortar and pestle until a fine powder is obtained. 

Traditionally the condenser cooling and freezing is achieved by direct expansion of frigorific fluids (HFCs allowed by the Montreal protocol), or nowadays liquid nitrogen (LN2), in the coils or the plates of the ice condenser. 

In liquid nitrogen (LN2) cooled detectors, the detector element (and in some cases preamplifier components), are housed in a clean vacuum chamber, which is attached to or inserted in a LN2 Dewar. The detector is in thermal contact with the liquid nitrogen, which cools it to around 77°K or —200°C. At these temperatures, reverse leakage currents are in the range of 10 —10 amperes. A cross-sectional view of a typical liquid nitrogen cryostat is shown in Fig. 6.2. 

During operation, the HPGe detector must be cooled to liquid nitrogen (LNa) temperature. A 40-liter "mother dewar sized to store enough LN2 for weeks of... 

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