Sample holder assembly

A TG apparatus consists of a precision balance (thermobalance), a furnace, sample holder assembly, temperature programmer and recorder and its schematic is shown in Figure 3.7. 

A schematic of a DSC sample holder assembly and instrument is shown in Figure 3.9 and a typical DSC curve for indium (standard) is shown in Figure 3.10. 

Figure 3.9 Schematic of DSC sample holder assembly and instrument.

Figure 1. Sample holder assembly, one-pass leaching system...

During the experiment, a layer of catalyst powder (or sieved meshed particles) is packed into the center tube holder. The alumina membrane disc holds the powder sample at the downstream side while allowing the reactant to flow through with minimal resistance. At the upstream side, a small amount of quartz wool is inserted to support the powder. This whole sample holder assembly is fastened to the outer connector and this whole tube assembly is enclosed in the quartz tube that is surrounded by a resistive heating unit. At each end of the tube, X-ray transparent windows are mounted. The thermocouple is placed close to the sample holder. The long gas inlet tube is heated by the tubular furnace, ensuring that the gas is preheated before it reaches the catalyst sample. The upper working temperature is 973 K, which is only limited by the materials of construction. 

Figure 16 Sample holder assembly of a monochromatic Laue camera. 1, Brass sample holder 2, collimator 3, beam stop 4, orienting arm 8, part attached to the cold tip of the cryocooler and holding the cold shroud 16, thermocouple. (From Ref. 132.)...

A wet sample was hermetically sealed in a sample pan. The empty sample pan and the sealed pan were weighed. The sealed pan was quickly frozen Inside the DSC chamber to -40 C and several minutes were allowed for the system to come to equilibrium. The sample holder assembly was then heated at a rate of 5 C/mln. A scanning speed of 5 C/mln was found to give the optimum values of peak height and peak spread. This minimized the errors In experimental measurements. After the DSC measurement, the pan was punctured... 

Figure 2. Photocalorimeter sample holder assembly S) sample cell, R) reference cell, DS) draft shield, L) UV lamp, V) quartz window.

Sample holder assembly Module of DSC (or DTA) instrument consisting of the sample and reference holders and the associated mechanical supports, electrical connections and heat sources. 

The structure of a classical differential thermal analyser is illustrated in Figure 2.1. The sample holder assembly is placed in the centre of the furnace. One holder is filled with the sample and the other with an inert reference material, such as a-alumina. The term reference material used in TA is frequently confused with the term standard reference material used for calibration, since in many other analytical techniques the same material is used for both purposes. However, a reference material in TA is a thermally inert substance which exhibits no phase change over the temperature range of the experiment. Thermocouples inserted in each holder measure the temperature difference between the sample and the reference as the temperature of the furnace is controlled by a temperature programmer. The temperature ranges and... 

When the sample holder assembly is heated at a programmed rate, the temperatures of both the sample and the reference material increase uniformly. The furnace temperature is recorded as a function of time. If the sample undergoes a phase change, energy is absorbed or emitted, and a temperature difference between the sample and the reference (AT) is detected. The minimum temperature difference which can be measured by DTA is 0.01 K. 

When measurements are made at temperatures below 40 °C, the sample holder assembly is cooled using a cooling apparatus. The most... 

The sample holder assembly, is then inserted in the acid pool (either Phosphoric acid or sulphuric acid). The temperature of the acid is maintained at the required temperature by the thermostatic bath. The acid pool contains a counter electrode to complete the circuit and a reference electrode with a lug in capillary to sense the potential at the test electrode surface. 

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