Calorimeter system

For substances containing elements additional to C, H, O and N a rotating bomb calorimeter is generally used. A typical rotating bomb calorimeter system is shown in figure B 1.27.4. With tiiis calorimeter considerably more water is added to the combustion bomb and the continuous rotation of the bomb both about the cylindrical axis and end over... 

Anonymous, V2P2 — The Premier Process Hazard Calorimeter System, Eauske and Assoc., Burr Ridge, IL. 

Instruction Manual ofTronac Model 550 Isothermal and Isoperibol Calorimeter System. Tronac Incorporated. 

The Sikarex safety calorimeter system and its application to determine the course of adiabatic self-heating processes, starting temperatures for self-heating reactions, time to explosion, kinetic data, and simulation of real processes, are discussed with examples [1], The Sedex (sensitive detection of exothermic processes) calorimeter uses a special oven to heat a variety of containers with sophisticated control and detection equipment, which permits several samples to be examined simultaneously [2]. The bench-scale heat-flow calorimeter is designed to provide data specifically oriented towards processing safety requirements, and a new computerised design... 

There are many excellent differential scanning calorimeter systems available which can be used to measure the specific heat which, when combined with the sample density can be used to give c . The thermal diffusivity (which can be important for thermal imaging systems if the target is not reticulated) can be measured directly on a pyroelectric substrate using the laser intensity modulation method described by Lang [23],... 

FIGURE 15.15 Combustion efficiency (%) of various PC/ABS materials calculated using the THE/ML measured in the cone calorimeter, and the heat release per ML for the complete combustion of the volatiles monitored in the PCFC. Systems that do not show flame inhibition show combustion efficiencies of around 1, according to the well-ventilated fire scenario of the cone calorimeter. Systems, in which adding aryl phosphates result in flame inhibition, show combustion efficiencies of around 0.8. When the release of phosphorus is reduced by competing reactions in the solid state, combustion efficiencies of between 0.8 and 1 are observed. 

A lab technician places a 5.00 g food sample into a bomb calorimeter that is calibrated at 9.23 kJ/°C. The initial temperature of the calorimeter system is 21.0 ,C. After burning the food, the final temperature of the system is 32.0°C. What is the heat of combustion of the food in kj/g ... 

As reviewed in Section 3.1.2.3, reaction calorimeters can be used to better understand and characterize scale-related process phenomena, such as mixing and heat transfer. A heat flow calorimeter, the Mettler RCle, is shown in Figure 1. A schematic of a similar calorimeter system is shown in Figure 2 [16]. A heat flow calorimeter can be used to estimate ... 

FIGURE 1 Mettler RCle heat flow calorimeter system (www.mt.com). 

The standard calorimeter system for this series of experiments was specified as the NBS calorimeter containing the Parr fluorine combustion bomb plus sample ampoule. The standard bomb was defined as the Parr fluorine combustion bomb plus sample ampoule minus the water, the benzoic acid pellet, the Hastelloy cup containing the pellet, the oxygen, and the nitrogen used to pressurize the ampoule. 

Determine C(S), the heat capacity of the calorimeter system, from... 

In a series of publications, Stevenson et al. have demonstrated that the enthalpies of generation of polyacene dianions can be obtained by calorimetric measurements. Compared to their calculated instability in the gas-phase 70), THF solutions of polycyclic dianions are thermodynamically and kinetically stable as evidenced by their spontaneous formation and persistence. The solvation energy of the dianions plus that of two cations must overcome the repulsive interaction of the charges. This aspect has been demonstrated by Stevenson in his studies on the cyclooctatetraene dianion 70). The dianion sodium salts were prepared in THF in thin-walled glass bulbs and the bulbs were crushed under water in a calorimeter system. The heat of aquation of the solvent is taken into account and thus, the net change in the heat content of the calorimeter vs. the millimoles of dianion salt is obtained. The plots are linear and the slopes represent the enthalpies of the following reaction (Eq. 20) ... 

Thermal conductivity was measured by the hot wire method. The principle involved in the measurement has been well explained by Carislaw and Jaeger (1959). Specific heat was measured by DSC (Differential Scanning Calorimeter) System TA 2910 (DuPont, U.S.A.) with heat flux type. The temperature differences between the reference material and the target specimen were measured during heating. Measurements were conducted twice at a specified temperature and temperature is varied from room temperature to 100 °C. Relationship between specific heat and temperature was linear and the result is summarized in table 1 and figure 2. 

Fig. 3.36 Arrangement of the USSR calorimeter system / compressor 2 rotameter 3 rotameter 4 manometer 5 wattmeter 6 ignition regulator 7 stirring engine S calorimeter 9 filter 10 rotameter 11 gas washers 12 vacuum pump...

FIG. 4 (a) Schematic of Tian-Calvet type of calorimeter system and (b) thermopile response curve. 

It results from Eqs (3.12) and (3.13) that the calorimeter systems described by these equations are open and closed nonadiabatic-nonisothermal (n-n) systems. For the open calorimetric systems described by Eq. (3.12), heat and mass exchange occur simultaneously. 

For a sufficiently fine subdivision of the body, it is possible to find a suitably exact solution of the heat conduction problem. Several FEM software packages are available on the market. The ANSYS and the COMSOL systems are often used by calorimeter-developing corporations. The software can be used to define the time-dependent heat flux curves at any site of the calorimeter system and also to indicate the temperature field if this is necessary for the purposes of the discussion and for a better understanding including heat leaks of all kinds. 

Figure 6.16 Temperature-time course in the scanning calorimeter system with test substance without phase transition (top), test substance with a sudden exothermic transition middle), and test substance with an endothermic phase transition (bottom).

One method of cooling the calorimeter system is to put it inside a low-temperature thermostat (cryostat see later). This method is often used in low-temperature calorimetry and works down to temperatures well below 1K. 

Heat conduction in solid bodies is particularly suitable for quantitative measurements of heat exchanged (i.e., generated or consumed in the calorimeter system) vdth the surroundings. In a suitably designed instrument, the heat flow rate

solid body with a defined thermal resistance between the calorimeter system and the surroundings can be made entirely dependent on the temperature difference AT measured at the said thermal resistance. On these grounds, a record of the time course of this local temperature difference provides a means for the measurement of heat flow rates if the specific calibration factor K is known 0= KAT... 

The following considerations are formulated for a single heat flow calorimeter system, but they also apply analogously to a twin calorimeter. Let AT = T i — Tp be the temperature difference at the thermal resistance (see Figure 7.15). At steady state, the heat flow follows the relationship 0 = —AT/Rth (see Section 4.1). 

Isoperibol (quasi-isothermal) calorimeters are used in medicine and biology for determinations of the metabolic heats of organisms under various conditions (Dauncey, 1991). Here the calorimeter system (container or chamber) is large enough to accommodate one animal or person in relative comfort. The measurement principle is similar to the upper examples the container for the organism, positioned in thermostatized surroundings, is enclosed in a uniform layer or wall of a heat conductive material, and the temperature difference between the two... 

Hnedkovsky et al. (2002) constructed an isoperibol flow calorimeter for the determination of heat capacities of liquids at temperatures of up to 700 K and pressures of up to 35 MPa. The sample flowing through the calorimeter system is heated by an electrical heater, and the power needed for a constant temperature rise is measured relative to that for a reference fluid (e.g., water) in a second tube. In other words, this is a differential flow calorimeter that has mainly been used to measure the heat capacity of dilute solutions (with the pure solvent as the reference medium). 

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