Samples cooling accessories

Dynamic Mechanical Analysis and Stress Relaxation Behavior. Samples were compression molded into bars of the dimensions 38.xl2.5x0.78 0.007 mm and 65.x9.7xl.7 0.007 mm in a Carver laboratory hot press model C. A TA Instruments 983 DMA, which was operated in the fixed frequency mode, was used to characterize the storage and loss moduli as a function of temperature. Samples were scanned at fi-equencies from 0.05 to 10.0 Hz over a temperature range from -150 C to above the glass transition temperature. The displacement was 0.4 - 0.6 mm. Stress relaxation curves were determined for the same size samples at a constant strain. The sample was displaced for 10.0 minutes and then allowed to recover for 10.0 minutes. The stress data were taken in five degree increments. A microprocessor controlled Liquid Nitrogen Cooling Accessory (LNCA) was used for sub-ambient operations. 

Perkin-Elmer DSC 7 equipped with a liquid nitrogen controlled cooling accessory heating rate 5 °C min" . Sample mass ca 10 mg. 

A new sample handling accessory with which films of constant thicknesses can be prepared has been introduced by Phillips Analytical. The plastic film press contains a thermostatically controlled oven unit that is calibrated up to 300 °C. It also contains a cooling facility which may be connected to a low-pressure compressed air supply to cool the prepared films rapidly. Reproducible thickness is ensured by using a set of brass dies that can be heated and cooled quickly. The dies can produce films of 20, 50, 100, 200, and 500 pm thickness. 

The importance of the coolant of the sample holder should be emphasized. If a mechanical cooling accessory is used, it should be turned on at least 2 h prior to the actual measurements in order to achieve thermal equihbrium. 

We measured the coefficient of thermal expansion, CTE, of RX-55-AE-5 using a TA Instruments Model 2940 TMA that was controlled by a TA 500 Thermal Analyzer equipped with a TMA Mechanical Cooling Accessory [6,7]. A quartz micro-expansion probe sat on top of all samples with a force of 0.01 Newtons (N). The change in the length of the sample was as it was heated or cooled was measured by a linear transformer that converted the vertical distance of the quartz motion probe and was recorded by the TA Instrument software. Ultra high purity nitrogen carrier gas was used at a constant flow rate of 100 cm /min. Samples were heated at a linear heating rate of 3°C /min. 

Dynamic mechanical analysis was performed in a TA-Q800 DMA and a Gas Cooling Accessory (Model CFL-50) for sub-ambient experimerrts. Film samples were tested in tension mode from -130 °C to 100 °C at a heating rate of 3 C/min and frequency of 1 Hz. 

Sample preparation for more specialized work can require more intensive procedures and accessories [49]. Stages have been made for the SEM to accommodate a variety of experiments [50]. Heating, cooling, and mechanical manipulation would be useful for most pharmaceutical materials, but other... 

The macromode spectra described here are acquired with an Instruments SA Jobin Yvon Ramanor HG.2S system. Sample excitation is done with either argon or krypton ion lasers. This scanning spectrometer has a thermoelectrically cooled PMT detector and is fitted with a modified Nachet 400 microscope accessory for Raman microprobe work. The microprobe is capable of providing information from domains as small as 1 // in diameter. 

Detailed experimental procedures for obtaining infrared spectra on humic and fulvic acids have been reported previously 9,22,25-26) and will be briefly described here. Infrared spectra were taken on the size-fractionated samples by using a Fourier transform infrared spectrometer (Mattson, Polaris) with a cooled Hg/Cd/Te detector. Dried humic and fulvic materials were studied by diffuse reflectance infrared spectroscopy (Spectra Tech DRIFT accessory) and reported in K-M units, as well as by transmission absorbance in a KBr pellet. Infrared absorption spectra were obtained directly on the aqueous size-fractioned concentrates with CIR (Spectra Tech CIRCLE accessory). Raman spectra were taken by using an argon ion laser (Spectra-Physics Model 2025-05), a triple-grating monochromator (Spex Triplemate Model 1877), and a photodiode array detector system (Princeton Applied Research Model 1420). All Raman and infrared spectra were taken at 2 cm resolution. 

The diffuse reflectance accessory (model DRA-2CN, Harrick Scientific) was modified with a three-dimensional translational stage to optimally position the sample for maximum radiation throughput (15). The sample cell (model HVC-DRP, Harrick Scientific) was heated by a resistive heater contained within a post that housed a sample cup. The base of the sample cell also contained an external connector for evacuation and a second port, which was sealed with a septum and used for the introduction of pyridine by microsyringe. The sample cell cover contained a channel and connectors for water cooling and ZnSe windows (12 mm in diameter) for the IR radiation. The base and cover of the cell were sealed vacuum-right with an O-ring. 

Data collection. Two data sets are used to demonstrate the multiscale cluster analysis method and have been kindly provided by Dr. Roy Goodacre at Institute of Biological Sciences. University of Wales, Aberystwyth [64,65]. Ten microlitre aliquots of bacterial suspensions were evenly applied onto a sand-blasted aluminium plate. Prior to analysis the samples were oven-dried at 50°C for 30 min. Samples were run in triplicate. The FT-IR instrument used was the Bruker IFS28 FT-IR spectrometer (Bruker Spectro-spin, Banner Lane, Coventry, UK) equipped with an MCT (mercury-cadmium-telluride) detector cooled with liquid Ni. The aluminium plate was then loaded onto the motorised stage of a reflectance TLC accessory. The wave-... 

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