Thermal control systems

Sulphuric acid at 93% was added to p-nitrotoluene. The temperature reached 160°C due to a failure of the thermal control system. The sulphonic acid formed decomposed violently at this temperature. The post-accident investigation showed that the decomposition started between 160 and 190 C. In fourteen minutes the temperature rose to 190-224°C and in one minute and thirty seconds to 224-270°C. A large volume of gas was then released during the eruption. The phenomena caused by the decomposition of nitrated derivatives in the presence of sulphuric acid will be addressed several times. What these incidents have in common is the formation of large carbonised volumes. This phenomenon is common with sulphonic acids. The nitro group role is to destabilise intermediate compounds and final compounds and to generate... 

A high optical transparency is a basic requirement for optical applications. However, conventional polyimides such as PMDA/ODA have a low optical transparency owing to their dark yellow coloration (they are semitransparent, not opaque). Colorless polyimides have been developed for use in space components, such as solar cells and thermal control systems for the first time. ... 

Carbon material can be used as a compact "sandwich" with cylindrical or flat heat pipes, applied as thermal control systems. The dynamic mathematical thermal model of the sorbent bed (Fig. 10) has following constituents [12] ... 

Leimkuehler TO, Spelbring C, Reeves DR, and Holt JM, Development of the next generation gas trap for the space station internal thermal control system. Report number 2003-01-2566, SAE International, 2003. 

Typically, the temperature drop between the evaporator and condenser of a heat pipe is of particular interest to the designer of heat pipe thermal control systems and is most readily found by utilizing an analogous electrothermal network. Figure 12.4 illustrates the electrothermal analogue for the heat pipe illustrated in Fig. 12.1. As shown, the overall thermal resistance is composed of nine different resistances arranged in a series-parallel combination. These nine resistances can be summarized as follows ... 

TBD. Possible causes Include thermal control system malfunction, solar radiation protection inadequate, Insufficient radiator heat rejection. 

Earlier it was stated that press manufacturers have made substantial improvements to the temperature control of platens. This work has to be extended to ensure that the moulds become integrated into the system. Some thermal control systems are available which allow such control, but cost is cited against their use to eliminate cavity-to-cavity variation. It is not logical to expect any system to maintain close temperature control over an area of half a square metre from one pair of thermocouples Greater control will pay real dividends by allowing the technologist to optimise a cure time that is based on equal crosslink density rather than the cure time required for the coldest cavity. 

Thermal Control System. The thermal control system uses active and passive methods of moving heat to maintain normal operating temperatures for critical components. Active methods include the use of heaters to warm cold objects and pump-driven fluids to move heat from hot to cold areas. Passive devices include reflective coatings and insulation. 

Cady, E.C., Blackmon, J.B., 1974. Developments in low-gravity cryogenic propellant acquisition and thermal control systems. In AIAA-74-1155, 10th Propulsion Conference, San Diego, CA, October 21-23. 

A test conducted to verify the adequacy of the thermal model, the adequacy of the thermal design, and the capability of the thermal control system to maintain thermal conditions within established mission limits. 

The thermal control system is treated with a conventional first-degree cold redundancy, with the exception of some unrehable sensors (e.g. thermistors) often mounted in majority vote. 

Over time, the orientation of a system relative to the sun will change, and at times there will be no solar flux, requiring that the thermal control system account for this absence of external heating. 

Several important observations resulted from the thermal control system efforts. These include the following ... 

The embossing machine used in the current study has been described in detail in [16]. It consists of two copper platens heated and cooled by oil flowing through several internal passages. The oil is heated and cooled in a separate thermal control system. The platens are mounted to an Instron model 5869 load fi ame, which controls the embossing force and displacement. A layer of silicone rubber provides for fine alignment and ensures an even pressure distribution across the part (Figure 1). 

Traditional injection molding method was tried to mold the nozzle plates but lail. Typical condition used was injection speed of 100 mm/s and mold tenperature of 80°C. Figure 6 shows a short shot caused by grating effect. After applying the vario-thermal control system and high injection speed fimction, good results were obtained finally. 

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