Cooling shielding

Substances applied to or incorporated in a combustible material (e.g. organic polymers, nylon, vinyl and rubber, etc.) to reduce flammability. Act by retarding ignition, control/douse burning, reduce smoke evolution. Slow down or interrupt the self-sustained combustion cycle when the heat-flux is limited. Flame retardants (FRs) improve the combustion behaviour and alter the combustion process (cool, shield, dilute, react) so that decomposition products will differ from nonflame retarded articles. FRs are usually divided into three classes ... 

Single-stage GM coolers are mainly used for communication electronics and cryop-umping, cryogen free magnets and for cooling shields. 

Inner vapour cooled shield Middle vapour cooled shield... 

Figure 6.15. The apparatus of Schnepf and Schnockel (2002) for the preparation and co-condensation of A1 (or Ga) mono-halide. 1 stainless steel vessel, 30/ 2 solvent input LM/D 3 drainage channel 4 A1 in the graphite cell with resistance heating 5 cooling shield 6 Dewar with dry ice (—78°C) 7 cooling water. HX hydrogen halide gas HV high vacuum.

Martnovskii, V. S., Cheilyakh, V. T., and Shnaid, T. N., "Thermodynamic Effectiveness of a Cooled Shield in Vacuum Low-Temperature Insulation," Isvestiya Akadami Nauk SSR, Energitika Transport, No. 2 (1971) English translation appears in reference 8, p. 263 (1980). 

The circular atom microwave spectroscopy experimental set-up is sketched on Fig. 1-a. A thermal beam of Li atoms crosses three sections of the apparatus the excitation, the microwave interaction region and the detection zone. The whole set-up is protected from room temperature thermal radiation by a liquid nitrogen cooled shield (which can be replaced in a later stage of the experiment by a liquid helium cooled one). 

The first 50 mm OD quartz reactor with pyrex flow straightner was wrapped with electrical heater tape and installed behind a large water cooled shield. The shield had a 10 cm diameter circular hole located in it for admission of the solar flux into the reactor. Behind the reactor, a water cooled semi-circular (cross section) cylindrical backplate prevented radiation from entering the work area through the back of the reactor. Unfortunately, the first reactor cracked at the pyrex/quartz joint when the upper portion of the reactor was accidentaly heated to a temperature in excess of its 100°C design operating temperature. 

A water cooled shield and thermal insulator, containing y- and n-absorbing material. 

The pressure sensors are connected close to the piston pump. Pressure can be detected with a precision of 4 kPa. The connection between the cryostat and the heating/cooling shield of the calorimetric block is made via two flexible... 

A liquid helium storage dewar utilizes a vapor cooled shield to intercept some of the heat leak into the dewar. The overall heat transfer coefficient between the warm 300 K outer container and the vapor shield is 6 mW/m K and the overall heat transfer coefficient between the vapor shield and the cold 4.2 K surface of the inner container is 8 mW/m K. The mean specific heat of the cold helium gas flowing in contact with the vapor shield is 5.39 kJ/kg K. If the heat of vaporization of the helium in the container is 19.69 kJ/kg, determine (a) the temperature of the shield, (b) the heat transfer rate to the vapor shield, and (c) the heat transfer rate to the inner container. 

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