Microwave thermal analysis

Thermal desorption of solid traps by microwave energy is unsuitable for thermally labile compounds. In microwave thermal analysis [431] the (solid) sample is heated directly via interactions of the microwaves with the sample, providing more even heating and reduction of temperature gradients in comparison to heating with electrical furnaces. By passing air over a microwave-heated volatile sample evolved gases may be collected [432]. 

G. M. B. Parkes et al.. Development of a new instrument for performing microwave thermal analysis. Review of Scientific Instruments, 71, 168-175 (2000). 

Parkes, G.M.B. Barnes, P.A. Bond, G. Charsley, E.L. Qualitative and quantitative aspects of microwave thermal analysis. Thermochim. Acta 2000, 356, 85-96. 

A recent paper by Paikes and sv-workers (381 descnhes a new technique of microwave thermal analysis fiheir suggested abbreviation is M3XTA). The advantages of such a... 

In microwave thermal analysis (MWTA) microwaves heat the sample by direct interaction (rather than by conduction of heat as in conventional thermal analysis) and can penetrate up to about 2 cm [38]. This reduces temperature gradients in masses up to 0.5 g. The method allows the study of thermal and dielectric properties of materials. Microthermal analysis methods allow to reduce the amount of material observed and considerably increase the range of problems that can be tackled cfr. Chp.2.1.6.1). 

Multiphoton ionisation, c/r. MPI Microwave thermal analysis Microsample X-ray analysis Micro X-ray fluorescence (c/r fiXRF)... 

Chapters 10-12 cover important aspects of coke formation in metal tubular reactors during pyrolysis of hydrocarbons. Chapters 13 and 14 are concerned with coal and lignite pyrolysis. Chapters 15 and 16 deal with pitch formation from, respectively, heavy petroleum fraction and tar sand bitumen. Chapters 17 and 18 cover studies on the mechanisms of thermal alkylation and hydropyrolysis. Chapters 19 and 20 on oil shale deal with the properties of oil shale and shale oil as developed by techniques of microwave heating and thermal analysis. 

As indicated in the previous sections, the antioxidant content in plastic material is often determined by chromatographic methods. Another widely used technique for polymer characterization is thermal analysis with differential scanning calorimetry (DSC). When the oxygen induction time (OIT) for a sample containing a phenoHc antioxidant is measured, a significant oxidative exothermic response is obtained in the DSC when all the phenolic antioxidant in a sample is consumed. The OIT is thus directly related to the antioxidant content in the material and to the stabihzing function, i.e. the antioxidant efficiency in the sample, if the consumption of phenolic antioxidants obeys zero-order kinetics at the temperature used [44]. Table 1 shows the amount of the antioxidant Irganox 1081 in polyethylene (PE) determined by HPLC and extraction by microwave assisted extraction (MAE),... 

Trinh, V. D. and Khanh, H. C., GC Bin quartz tubes for the sampling of indoor air nicotine and analysis by microwave thermal desorption-capillary gas chromatography, J. Chromatogr. Set, 29, 179-183, 1991. 

Thermal analyses of other dental polymers have also been reported. The compositions of waxes have been studied by differential thermal analysis (DTA) [64-66] and DMA [67], Conventional DSC and DMA recently showed the superiority of microwave-processed denture base resins to those processed by the slower traditional dental laboratory heating regimen [68], In contrast, comparisons of Tg and other relevant properties for a soft denture liner that was processed by the dental laboratory procedure and a more convenient chairside procedure indicated that both procedures yielded equivalent results [69],... 

Complementary data on food and food constituents are obtained by other thermal analysis techniques, such as thermomanometry, thermogravimetry (TG), thermomicroscopy or hot stage microscopy (HSM), differential mechanical (thermal) analysis (DMA or DMTA), titration calorimetry, and microwave dielectric measurements during temperature scan. 

Around lOOX, thermal analysis measurements with open cracibles distinguish among adsorbed, absorbed, and crystal water. Thus, DSC curves, TG curves, or microwave dielectric measurements give information on water content or on the... 

M Ollivon, S Quinquenet, M Seras, M Dehnotte, C More. Microwave dielectric measurements during thermal analysis. Thermochim Acta 725 141-153 (1988). SD Holdsworth. Dehydration of food products. A review. J Food Technol 6 331-370 (1971). 

Sections are included on conventional synthesisers, microwave synthesisers, high-throughput FTIR spectroscopy, MALDI-TOF mass spectroscopy, scanning probe microscopy and nanoindentation, X-ray analysis and X-ray photoelectron spectroscopy, and thermal analysis. 

Emission spectroscopy is the analysis, usually for elemental composition, of the spectmm emitted by a sample at high temperature, or that has been excited by an electric spark or laser. The direct detection and spectroscopic analysis of ambient thermal emission, usually ia the iafrared or microwave regioas, without active excitatioa, is oftea termed radiometry. la emission methods the sigaal iateasity is directiy proportioaal to the amouat of analyte present. 

The apphed pretreatment techniques were digestion with a combination of acids in the pressurized or atmospheric mode, programmed dry ashing, microwave digestion and irradiation with thermal neutrons. The analytical methods of final determination, at least four different for each element, covered all modern plasma techniques, various AAS modes, voltammetry, instrumental and radiochemical neutron activation analysis and isotope dilution MS. Each participating laboratory was requested to make a minimum of five independent rephcate determinations of each element on at least two different bottles on different days. Moreover, a series of different steps was undertaken in order to ensure that no substantial systematic errors were left undetected. 

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