Pressurized differential scanning calorimeter

Figure 2. Heat flow vs. temperature obtained with a high pressure differential scanning calorimeter for two samples of YBa2Cu307 x.

Kodali, D.R. Oxidative stability measurement of high-stability oils by pressure differential scanning calorimeter (PDSC). J. Agric. Food Chem. 2005, 53, 7649-7653. Kris-Etherton, P.M. Harris, W.S. Appel, L.J. Fish consumption, fish oil, omega-3 fatty acids and cardiovascular disease. Circulation 2002, 106, 2747-2757. 

In the CSM laboratory, Rueff et al. (1988) used a Perkin-Elmer differential scanning calorimeter (DSC-2), with sample containers modified for high pressure, to obtain methane hydrate heat capacity (245-259 K) and heat of dissociation (285 K), which were accurate to within 20%. Rueff (1985) was able to analyze his data to account for the portion of the sample that was ice, in an extension of work done earlier (Rueff and Sloan, 1985) to measure the thermal properties of hydrates in sediments. At Rice University, Lievois (1987) developed a twin-cell heat flux calorimeter and made AH measurements at 278.15 and 283.15 K to within 2.6%. More recently, at CSM a method was developed using the Setaram high pressure (heat-flux) micro-DSC VII (Gupta, 2007) to determine the heat capacity and heats of dissociation of methane hydrate at 277-283 K and at pressures of 5-20 MPa to within 2%. See Section 6.3.2 for gas hydrate heat capacity and heats of dissociation data. Figure 6.6 shows a schematic of the heat flux DSC system. In heat flux DSC, the heat flow necessary to achieve a zero temperature difference between the reference and sample cells is measured through the thermocouples linked to each of the cells. For more details on the principles of calorimetry the reader is referred to Hohne et al. (2003) and Brown (1998). 

The simpler and most reliable approach to the use of the DIERS methodology is the use of FAUSKY s reactive system screening tool (RSST). It is an experimental autoclave which simulates actual situations that may arise in industrial systems. The RSST runs as a differential scanning calorimeter that may operate as a vent-sizing unit where data can readily be obtained and can be applied to full-scale process conditions. The unit is computerized and records plots of pressure vs. temperature, temperature vs. time, pressure vs. time, and the rates of temperature rise and pressure rise vs. the inverse of temperature. From these data it determines the potential for runaway reactions and measures the rates of temperature and pressure increases to allow reliable determinations of the energy and gas release rates. This information can be combined with simplified analytical tools to assess reactor vent size requirements. The cost of setting up a unit of this kind is close to 15,000. 

Differential Scanning Calorimeter Studies. A Perkin Elmer DSC 2 differential scanning calorimeter modified with a GE H3T7 medium pressure mercury arc lamp and a filter system was used in these studies. The apparatus is similar to that described by previous workers from this laboratory ( ). Approximately 10 mg samples of the monomer-catalyst solutions were placed in the usual aluminum cups. Except where noted, irradiations were carried out in an isothermal mode at 30°C. 

Accurate enthalpies of solid-solid transitions and solid-liquid transitions (fusion) are usually determined in an adiabatic heat capacity calorimeter. Measurements of lower precision can be made with a differential scanning calorimeter (see later). Enthalpies of vaporization are usually determined by the measurement of the amount of energy required to vaporize a known mass of sample. The various measurement methods have been critically reviewed by Majer and Svoboda [9]. The actual technique used depends on the vapour pressure of the material. Methods based on... 

A comprehensive experimental research program to investigate the effects of pressure on the products of steam gasification of biomass is currently underway. A stainless steel, tubular microreactor similar to the quartz reactor described earlier has been fabricated for the experimental work. The pyrolysis furnace used with the quartz reactor system has been replaced in the pressurized steam system by a Setaram Differential Scanning Calorimeter (DSC). The DSC provides for quantitative determination of the effects of pressure on pyrolysis kinetics and heats of reaction. 

For prediction of mold filling and flow-through dies, computer modelling is increasingly used. In addition to viscosity, measurements may be needed for specific heat, shrinkage, thermal conductivity, and pressure- volume -temperature (PVT) relationship. A differential scanning calorimeter (DSC) can be used for specific heal measurements. 

Once the polymers are manufactured further characterization takes place prior to processing or during the process itself The two key properties that are critical are Tg and Mooney viscosity. The most convenient way to measure the Tg is by differential scanning calorimeter. Mooney viscosity is an industry specific test procedure that is used for assessing the processability of the rubber. Mooney viscosity (ASTM D1646) is measured by rotation of a disk inside a cavity imder pressure. This equipment does not measure the viscosity, but rather the torque required to rotate the disk at 100°C at a rate of 2 rpm. The results are usually given as... 

The fiber diameter distribution was studied by microscopy (optical microscope, Hitachi TM-1000 scanning electron microscope). Fiber orientation was studied by using birefringence and polarization IR-spectroscopy (SPECORD M 80 IR-spectrometer). Crystalline phase of polymer was studied by differential scaiming calorimetry (DSC) (differential scanning calorimeter). The packing density of fibrous materials was calculated as a function of airflow resistance variation with a special manometric pressure unit [7]. 

DOE Department of Energy DOE Design of Experiments dp dewpoint dP differential pressure DP degree of polymerization DSC differential scanning calorimeter DSD Duales System Deutschland (German Recycling System)... 

Basically, the methods consist of a variety of calorimetric methods and a few non-calorimetric methods. In calorimetry the following methods are nsed adiabatic, isoperibol, isothermal, heat condnction, drop and differential scanning calorimeters, and differential thermal analysis. Cryoscopic, vapor pressure, and enthalpy of solution methods are considered to be non-calorimetric methods. 

The first differential scanning calorimeter was introduced by Watson et al. (1964) (Fig. 10.2(a)). A number of new developments in the instrumentation have since been made. The temperature scan is controlled, and data are collected and analysed by computers in today s instruments. Simultaneous measurements of differential temperature (AT) and sample weight, i.e. combined DTA and TG as well as combined DTA and TO A, are now commercially available. High-pressure DTA instruments have been in use since the early 1970s. In 1966, Cohen and co-workers constructed a DTA cell which could be... 

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