scholarly journals Application of Thermal Methods to Analyze the Properties of Coffee Silverskin and Oil Extracted from the Studied Roasting By-Product

2020 ◽  
Vol 10 (24) ◽  
pp. 8790
Author(s):  
Agata Górska ◽  
Rita Brzezińska ◽  
Magdalena Wirkowska-Wojdyła ◽  
Joanna Bryś ◽  
Ewa Domian ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Oxidative Stability ◽  
Reliable Data ◽  
Scanning Calorimetry ◽  
Thermal Methods ◽  
Modulated Differential Scanning Calorimetry ◽  
Coffee Silverskin ◽  
Derivative Thermogravimetry ◽  
Coffee Roasting

The aim of the study was to characterize the thermal properties of coffee silverskin and fat extracted from the material by using differential scanning calorimetry, modulated differential scanning calorimetry and thermogravimetry/derivative thermogravimetry. Additionally, the thermokinetic parameters, oxidative stability and fatty acid composition of the extracted oil were defined. Thermal decomposition of the studied coffee roasting by-product under oxygen occurred in three defined stages. The most significant changes in weight were observed in the region of 200–500 °C and correspond to polysaccharide decomposition. These results are in agreement with the data obtained from the differential scanning calorimetry curve. On the curve course of silverskin, two main exothermic peaks can be observed with a maximum at 265 and 340 °C. These exothermic events represent the transitions of hemicellulose and cellulose. Fat extracted from silverskin turned out to be a source of polyunsaturated fatty acids with the recommended n-6 to n-3 ratio reaching the value 4:1. The studied fat was characterized by low oxidative stability. Considering the obtained results, it can be stated that thermal analysis can provide fast and reliable data concerning the composition and properties of coffee silverskin and coffee silverskin oil.

Determination of Total and Free Water in Triple Superphosphate Fertilizers by Using Thermal Analysis

1985 ◽  
Vol 68 (4) ◽  
pp. 788-793
Author(s):  
Krystyna Kostyrko ◽  
Malgorzata Skoczylas ◽  
Andrzej Klee
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Free Water ◽  
Total Water ◽  
Triple Superphosphate ◽  
Scanning Calorimetry ◽  
Thermal Methods ◽  
Dehydration Processes ◽  
Derivatographic Analysis

Abstract Thermal analysis methods were used to study dehydration of triple superphosphate. A redrying procedure followed by Q-derivatographic analysis (under quasiisobaric and quasiisothermal conditions) as well as differential scanning calorimetry (DSC) was applied. Attempts were made to establish the correct drying-oven temperature for determination of water content, i.e., the temperature at which free or total water is removed from the fertilizer. Thermal decomposition of monocalcium orthophosphate monohydrate, the major component of triple superphosphate, was studied and a model was advanced for the reactions that occur during decomposition of this salt. The free water was completely released when superphosphate was heated at a constant temperature of 85°C. The total water was entirely released at 160°C. At 150°C, the process of removing the water of crystallization from the orthophosphate was disturbed by other concomitant dehydration processes which result in irreversible decomposition of this salt. The results obtained indicate that the thermal methods of analysis used are complementary.

Glass transformation, heat capacity, and structure of GexSe100−x glasses studied by temperature-modulated differential scanning calorimetry experiments

1997 ◽  
Vol 12 (7) ◽  
pp. 1892-1899 ◽  
Author(s):  
T. Wagner ◽  
S. O. Kasap ◽  
Kouji Maeda
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Heat Flow ◽  
Chalcogenide Glasses ◽  
Glass Transition Region ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Heat Flows ◽  
Glass Transformation

The recent novel temperature-modulated differential scanning calorimetry (DSC) (MDSCTM TA Instruments) technique has been applied to characterize the thermal properties of Ge–Se chalcogenide glasses in the glass transition region. All samples in this work were given the same thermal history by heating to a temperature above the glass transition, equilibrating, and then cooling at a rate of 5 °C/min to a temperature of 20 °C. The reversing and nonreversing heat flows through the glass transformation region during both heating and cooling schedules were measured, and the values of the parameters Tg, ΔH, Cp, and ΔCp, which characterize the thermal events in the glass transition region, were determined. The ability of determining the reversible heat flow in MDSC enables an accurate measurement of the true heat capacity (that normally associated with reversible heat flow), which could not be done hitherto in conventional thermal analysis where the detected heat flow is the total heat flow, the sum of reversing and nonreversing heat flows. The structurally controlled parameters Tg, ΔH, Cp, and ΔCp reveal extrema when the Ge–Se glass system reaches the average coordination number 〈r〉 = 2.67 at 33.3 at.% Ge which corresponds to the stoichiometric composition GeSe2. We also observed extrema in the composition dependence of the above thermal parameters at 20.0 and 40.0 at.% Ge which correspond to stoichiometric compositions GeSe4 and Ge2Se3 with average coordination numbers 2.40 and 2.80, respectively. No such clear local maxima below and above the 33.3 at.% Ge composition could be observed previously in thermal analysis. We compare our MDSC results with previously published works on glass transition in Ge–Se glasses and discuss the results in terms of recent structural models for chalcogenide glasses.

scholarly journals Combined thermal analysis of fluid plasticizers

2020 ◽  
Author(s):  
Chukwuemeka L. Ihemaguba ◽  
Kálmán Marossy
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Mechanical Analysis ◽  
Molecular Motions ◽  
Melting Points ◽  
Scanning Calorimetry ◽  
Thermal Methods ◽  
Thermally Stimulated Discharge Current ◽  
Butyl Phthalate

Abstract The paper deals with the study of plasticizers using different thermal methods. The literature data on the melting points of plasticizers proved uncertain; we intended to gather the data by other methods, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermally stimulated discharge (TSD). Results of ten plasticizers are demonstrated. During this work, we found that most of plasticizers have no well-defined melting point, and the solidification of plasticizer is similar to the glass transition of polymers. Only the di-n-butyl-phthalate showed regular crystallization. Thermally stimulated discharge current (TSD) method revealed that these compounds have several transitions –dispersion ranges assigned to different molecular motions.

Studies on bismaleimides and related materials: Part III. Synthesis and characterization of bismaleimiides derived from benzophenone, 1, 2-diphenylethane, 1, 4-diphenylbutane and condensed pyrazines

1994 ◽  
Vol 6 (1) ◽  
pp. 35-41
Author(s):  
P N Prestont ◽  
V K Shaht ◽  
S W Simpsont ◽  
I Soutar ◽  
N J Stewart
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Oxidative Stability ◽  
Thermal Gravimetric Analysis ◽  
Dynamic Mechanical Thermal Analysis ◽  
Synthesis And Characterization ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Scanning Calorimetry

New bismaleimides have been synthesised from diamines derived from benzophenone, 1,2-diphenylethane, 1,4-diphenylbutane, 2, 3-diphenylquinoxaline and 2, 3-diphenylnaphtho[2, 3-b]pyrazine. Cure profiles have been established by both differential scanning calorimetry (Dsc) and dynamic mechanical thermal analysis (DMTA). Cured resins prepared from the bismaleimide monomers were studied by thermal gravimetric analysis (TGA) with all materials exhibiting good thermal and thermo-oxidative stability.

scholarly journals A thermal analysis study of dithizone and dithizonates of mercury, silver and bismuth

2000 ◽  
Vol 25 (0) ◽  
pp. 9-17 ◽  
Author(s):  
Marisa CHAHUD ◽  
Marco Aurélio da Silva CARVALHO FILHO ◽  
Nedja Suely FERNANDES ◽  
Massao IONASHIRO
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Analysis Study ◽  
X Ray ◽  
Thermal Analysis Study ◽  
Derivative Thermogravimetry

Solid dithizonates of Hg(I), Ag(I) and Bi(III) have been prepared. Thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC), X ray diffraction powder patterns and elemental analysis have been used to characterize and to study the thermal stability and thermal decomposition of the dithizone and of these dithizonates.

scholarly journals Thermal analysis: basic concept of differential scanning calorimetry and thermogravimetry for beginners

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Nurul Fatahah Asyqin Zainal ◽  
Jean Marc Saiter ◽  
Suhaila Idayu Abdul Halim ◽  
Romain Lucas ◽  
Chin Han Chan
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Commercial Application ◽  
Scanning Calorimetry ◽  
Teaching Activities ◽  
Sample Decomposition ◽  
Calibration Baseline

AbstractWe present an overview for the basic fundamental of thermal analysis, which is applicable for educational purposes, especially for lecturers at the universities, who may refer to the articles as the references to “teach” or to “lecture” to final year project students or young researchers who are working on their postgraduate projects. Description of basic instrumentation [i.e. differential scanning calorimetry (DSC) and thermogravimetry (TGA)] covers from what we should know about the instrument, calibration, baseline and samples’ signal. We also provide the step-by-step guides for the estimation of the glass transition temperature after DSC as well as examples and exercises are included, which are applicable for teaching activities. Glass transition temperature is an important property for commercial application of a polymeric material, e.g. packaging, automotive, etc. TGA is also highlighted where the analysis gives important thermal degradation information of a material to avoid sample decomposition during the DSC measurement. The step-by-step guides of the estimation of the activation energy after TGA based on Hoffman’s Arrhenius-like relationship are also provided.

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