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Diathermal calorimeters

Adiabatic calorimeters, where the mm is to avoid any exchange of heat between the system S and the surrounding thermostat T Diathermal calorimeters, where the aim is, on the contrary, to favour the above heat exchange... [Pg.6]

Diathermal calorimeters, where the aim is, on the contrary, to favour the above heat exchange. [Pg.29]

In diathermal calorimeters, where one tries to exchange most of the heat with the surroundings, the surroundings determine the temperature which can therefore be controlled by the experimenter. [Pg.29]

Passive diathermal calorimeters are those in which good heat-exchange between the system S and the surrounding thermostat T is achieved by good thermal conduction. The sample temperature passively follows, here, the thermostat temperature and, except in transient situations, there is no heat stored in the system S, These calorimeters can also be called, quite correctly, thermal conduction calorimeters . [Pg.34]

The most common way, to-day, of measuring the heat exchanged in a passive diathermal calorimeter is to make use of a heat flowmeter (Tian-Calvet, [32-33], Wads5, [34], Du Pont heat-flux DSC, cf Figure 8). [Pg.34]

These are still diathermal calorimeters, where everything happens as if there was excellent heat exchange between the system S and the surrounding thermostat T. This means that the system temperature Ts closely follows that of the thermostat, Tj. The good heat exchange is, in reality, simulated . For that purpose, the thermal transfer between sample and thermostat is complemented or replaced by a physical phenomenon taking place in close contact with die sample and able to generate or remove heat in situ. [Pg.35]

Diathermal-conduction calorimeters-, sample temperature follows surround temperature by simple conduction. Either a heat flowmeter or a phase chc detection system is used. [Pg.62]

Diathermal-compensation calorimeters here again, sample temperature follows surroundings temperature (usually constant in adsorption experiments), but now by means of a power compensation within the sample cell (i.e. Joule or Peltier effect). This reduces the response time. [Pg.63]

Phase-change adsorption calorimetry. This was the earliest type of diathermal-conduction calorimetry and was originally developed in the form of ice calorimetry by Lavoisier and Laplace (1783), who weighed the liquid water, and by Bunsen (1870), who measured the change of volume. Dewar (1904) devised an elegant adsorption calorimeter at liquid air temperature the heat was evaluated from the volume of air vaporized. Of course, the temperature of the calorimeter is imposed by the temperature of the phase change. Because these calorimeters lack adaptability and cannot be readily automated, they are mainly of historical interest. [Pg.64]

The above adiabatic or diathermal functioning of a calorimeter can be achieved (irrespective of the final efficiency) either by simple design and construction (by means of appropriate thermal conductors or resistors R) or (see below) with the help of electronic control. Hence each of the two families above, can be further divided into two groups, which can be named passive and active , respectively. We therefore end up with four groups of calorimeters ... [Pg.29]

Comment after saying that isothermally jacketed calorimeters are an intermediate category, Skinner nevertheless ends with only two main groups, associating the isothermally jacketed calorimeters with the adiabatic ones (as is proposed in Sections 4.1 to 4.3 ). Also, he puts phase-change and conduction calorimeters in the same category. This idea was kept, under the name of passive diathermal , in section 4.4. The calorimeters forming, in section 4.5,... [Pg.39]

This classification still separates from each other the Adiabatic and the Ordinary (or Isoperibo)l calorimeters, but, under the heading of Isothermal or Extended Isothermal , introduces, as a whole, the family of calorimeters which are called, in sections 4,4. and 4,5 above, "Diathermal , a term certainly more appropriate than "Isothermal . [Pg.44]

Here, the author stresses the existence of Only two principles upon which heat measurement can be based, namely A) the law of conservation of energy and B) Newton s law for the rate of heat transfer. The same two principles are used, in section4.L, to distinguish two main families of calorimeters, namely the adiabatic and the diathermal... [Pg.48]

This type of microcalorimetry has been referred to as diathermal calorimetry and has been adopted by most adsorption calorimeters of the Tian-Calvet type [21]. [Pg.144]


See other pages where Diathermal calorimeters is mentioned: [Pg.34]    [Pg.34]    [Pg.35]    [Pg.765]    [Pg.765]    [Pg.345]    [Pg.34]    [Pg.34]    [Pg.35]    [Pg.765]    [Pg.765]    [Pg.345]    [Pg.134]    [Pg.362]   
See also in sourсe #XX -- [ Pg.29 , Pg.34 , Pg.35 ]




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