Compression calorimeter

Magee J W, Blanco J C and Deal R J 1998 High-temperature adiabatic calorimeter for constant-volume heat capacity of compressed gases and liquids J. Res. Natl Inst. Stand. Technol. 103 63... 

Adiabatic calorimeters have also been used for direct-reaction calorimetry. Kubaschewski and Walter (1939) designed a calorimeter to study intermetallic compoimds up to 700°C. The procedure involved dropping compressed powders of two metals into the calorimeter and maintaining an equal temperature between the main calorimetric block and a surrounding jacket of refractory alloy. Any rise in temperature due to the reaction of the metal powders in the calorimeter was compensated by electrically heating the surrounding jacket so that its temperature remained the same as the calorimeter. The heat of reaction was then directly a function of the electrical energy needed to maintain the jacket at the same temperature as the calorimeter. One of the main problems with this calorimeter was the low thermal conductivity of the refractory alloy which meant that it was very difficult to maintain true adiabatic conditions. 

Determination of Heat Liberated on Explosion with Calorimeter (99-104) Lead Block Expansion Test (Trauzl Test) (104-06) Compression Tests with Small Lead Blocks (106-08) Testing of Detonators, which include Sand Test and Nail Test (108-14) Water Resistance of Electric Detonators (114-15) Testing Burning (Safety) Fuse (115-18) Testing Detonating Fuse (118-19)... 

Dunkle s Syllabus (1957-1958) Shock Tube Studies in Detonation (pp 123-25) Determination of Pressure Effect (144-45) Geometrical and Mechanical Influences (145-48) Statistical Effects of Sensitivity Discussion on Impact Sensitivity Evaluation (148-49) Pressure in the Detonation Head (175) Temperature of Detonation (176) Charge Density, Porosity, and Granulation (Factors Affecting the Detonation Process) (212-16) Heats of Explosion and Detonation (243-46) Pressures of Detonation (262-63) A brief description of Trauzl Block Test, Sand Test, Plate Dent Test, Fragmentation Test, Hess Test (Lead Block Crushing Test), Kast Test (Copper Cylinder Compression Test), Quinan. Test and Hop-kinson Pressure Bar Test (264-67) Detonation Calorimeters (277-78) Measurements... 

We may classify all calorimeters into two groups when we limit the processes to those that involve only the work of expansion or compression those that operate at constant volume and those that operate at constant pressure. The application of Equation (9.1) to constant-volume calorimeters shows that the heat absorbed by the system equals the change of energy of the system for the change of state that takes place in the system. Similarly, the heat absorbed by the system in constant-pressure calorimeters is equal to the change of enthalpy for the change of state that takes place in the system according to Equation (9.2). 

It must also be introduced very slowly, so that the heat effect corresponding to the gas compression in the calorimeter may be calculated accurately, as explained by Rouquerol and Everett (Rouquerol et ai, 1980). This also helps to meet the previous requirement of efficient adsorptive pre-cooling or pre-heating. 

The liquid was first heated to a known temperature, then the tap was opened and the liquid forced by compressed air into the calorimeter. A platinum bellows type of calorimeter for corrosive liquids was described by Williams and Sivetz.4 Luginine enclosed the liquid in a platinum bulb which was heated in a vapour bath and then dropped into the calorimeter. 

Air is compressed to 22 atm. in a vessel which is kept in a water calorimeter. The work done during compression can be calculated from the initial and final pressures and volumes. The work done is completely converted into heat which is communicated to the calorimeter. The mean of several determinations by this method gave for one great calorie J = 436-1 kgm. The same experiment carried out in the reverse direction is an example of the conversion of heat into work. When the compressed gas is allowed to expand, heat is abstracted from the calorimeter and its temperature is lowered. Three experiments of this sort gave for J the values 449-8, 446-5, and 416-8 kgm. 

Rowlings, C.E. Wurster, D.E. Ramsey, P.J. Calorimetric analysis of powder compression II. The relationship between energy terms measured with a compression calorimeter and tableting behavior. Int. J. Pharm. 1995, 116, 191-200. 

The deactivated catalysts were also burned in a calorimeter under compressed air flowing at 40 ml/min. (Thermal Analysis Station TAS 100 - Rigaku - TG 8110). Analysis were performed by differential scanning calorimetry (TPO/DSC) and combustion heats were obtained by integration of the profiles and using appropriate calibration samples. 

Benzoic acid, CgHjCOOH, is often used to determine the heat capacity of a calorimeter. It is a solid that can be compressed into pellets. Its heat of combustion is accurately known ... 

For chemisorption at room temperature, equilibrium pressures are small and reversible compression by standard techniques is difficult. More than that, to permit clean operating conditions, calorimeters... 

An original route is that proposed by Ter-Minassian and Million in 1983 [44] with their pneumatic compensation calorimeter, represented in Fig 10. The tubular sample cell 4 is in good thermal contact with four metallic bulbs. Two of them operate like bulb 1 in the figure, Le. as pneumatic thermal detectors. They are filled with gas, say around 1 bar, and their pressure is compared, by means of a differential manometer, with the constant pressure of a reference reservoir 3 immersed in the surrounding thermostat block 5. Therefore, they detect any temperature change of the sample. The two oflier bulbs operate like bulb 2, i.e. as pneumatic energy-compensating devices. They are also filled with gas, say around 1 bar, but they are connected to flie piston-cylinder 7 which enables the heat of compression (or decompression) necessary to cancel the temperature difference between the sample and thermostat (as detected with the first set of bulbs) to be produced in the bulb. More recently, Zimmermaim and Keller built a comparable pneumatic compensation calorimeter whose calorimetric performances were carefully examined [45]. 

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