scholarly journals RETROGRADATION PROPERTIES OF HEAT MOISTURE TREATED (HMT) SAGO AND ARENGA STARCHES

2021 ◽  
Vol 17 (2) ◽  
pp. 28
Author(s):  
Dede Robiatul Adawiyah ◽  
Tomoko Sasaki ◽  
Kaoru Kohyama
Keyword(s):  
Differential Scanning Calorimetry ◽  
Moisture Content ◽  
Significant Influence ◽  
The Other ◽  
Avrami Exponent ◽  
Avrami Equation ◽  
Sago Starch ◽  
Scanning Calorimetry ◽  
Dynamic Viscoelasticity ◽  
Starch Retrogradation

This study aimed to investigate the retrogradation rate of heat moisture treated sago and arenga starches using different approaches, including a thermal approach using DSC (differential scanning calorimetry), a rheological approach using dynamic viscoelasticity as rheological and syneresis level. The autoclaving procedures prepared the HMT starches at 20% moisture content and warmed to 120°C for 60 min and 90 min for sago and arenga starches, respectively. The Avrami equation was used to express starch retrogradation kinetics based on gelatinization enthalpy (ΔH). The Avrami exponent (n) of HMT and native starches were close to 1.0 (0.77 – 1.20) indicates rapid nuclei growth of the crystal. HMT has a significant influence on the retrogradation of sago starch, both from the values of n and k of the Avrami equation. On the other hand, it does not have a significant effect on arenga starch. Based on the thermal approach (DSC), HMT significantly affects sago starch’s retrogradation rate, but there was no effect on arenga starch. The influence of HMT on the retrogradation rate of arenga starch was observed on rheology and syneresis approaches, although it was not as high as sago starch.

scholarly journals The Influence of the Nature of Redox-Active Moieties on the Properties of Redox-Active Ionic Liquids and on Their Use as Electrolyte for Supercapacitors

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6344
Author(s):  
Philipp S. Borchers ◽  
Patrick Gerlach ◽  
Yihan Liu ◽  
Martin D. Hager ◽  
Andrea Balducci ◽  
...  
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Binary Mixtures ◽  
Thermal Characteristics ◽  
The Other ◽  
Scanning Calorimetry ◽  
Imidazolium Ionic Liquids ◽  
Redox Active

In this work, two new redox-active ionic liquids, one based on 2,2,6,6-tetramethylpiperidine-N-oxide and the other based on 4,4′-bipyridine, are synthesized and characterized. A ferrocene-based redox-active ionic liquid is used for referencing the results. All ionic liquids are formed via salt-metathesis from halogenate to bis(trifluoromethylsulfonyl)imide. Their fundamental thermal characteristics are assessed with differential scanning calorimetry. While the imidazolium ionic liquids show no melting point, the phase transition is well observable for the viologen-based ionic liquid. The properties of the neat redox-active ionic liquids and of binary mixtures containing these ionic liquids (0.1 m) and 1-butyl-1-methyl pyrrolidinium-bis(trifluoromethylsulfonyl)imide have been investigated. Finally, the use of these binary mixtures in combination with activated carbon-based electrodes has been considered in view of the use of these redox-active electrolytes in supercapacitors.

Amorphous iron oxide prepared by microwave heating

2000 ◽  
Vol 15 (10) ◽  
pp. 2176-2181 ◽  
Author(s):  
Oleg Palchik ◽  
Israel Felner ◽  
Gina Kataby ◽  
Aharon Gedanken
Keyword(s):  
Phase Transition ◽  
Differential Scanning Calorimetry ◽  
Iron Oxide ◽  
Iron Pentacarbonyl ◽  
Microwave Oven ◽  
The Other ◽  
Scanning Calorimetry ◽  
Amorphous Iron ◽  
Domestic Microwave Oven ◽  
Crystalline Phase Transition

Amorphous iron oxide (Fe2O3) was prepared by the pyrolysis of iron pentacarbonyl [Fe(CO)5] in a modified domestic microwave oven in refluxing chlorobenzene as a solvent under air. The reaction time was 20 min. Partially separated particles of iron oxide, 2–3 nm in diameter, were obtained. The other part showed aggregated spheres with a diameter of 25–40 nm. Differential scanning calorimetry measurements showed an amorphous/crystalline phase transition at about 250 °C.

Effects of desiccation on temperate recalcitrant seeds: differential scanning calorimetry, gas chromatography, electron microscopy, and moisture studies on Quercusnigra and Quercusalba

1996 ◽  
Vol 26 (10) ◽  
pp. 1813-1821 ◽  
Author(s):  
K.F. Connor ◽  
F.T. Bonner ◽  
J.A. Vozzo
Keyword(s):  
Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Cell Wall ◽  
Fatty Acid ◽  
Moisture Content ◽  
Fatty Acid Content ◽  
Heat Content ◽  
Dry Weight ◽  
Scanning Calorimetry ◽  
Seed Moisture

Investigations into the nature of desiccation-sensitive, or recalcitant, seed behavior have as yet failed to identify exact causes of this phenomenon. Experiments with Quercusnigra L. and Quercusalba L. were conducted to examine physiological and biochemical changes brought about by seed desiccation and to determine if there were predictable changes in seed moisture content, in enthalpy (heat content) of seed moisture, in the lipid fraction, or in seed ultrastructure as viability declined. Quercusnigra intact acorn moisture contents at 50% and 5% viability were 15% and less than 14%, respectively; those of intact Q. alba at 50% and 0% viability were much higher, 32% and 22%, respectively. Generally, it was found that as the seeds of both species dried, the moisture content of the axes remained high (26–27%), even after 9 days of drying. In Q. nigra acorns, there was little difference in average percent moisture lost per day among axes, proximal cotyledon tissue, and distal cotyledon tissue. Quercusalba acorns, however, lost moisture more rapidly from the axes than from the cotyledons. This was probably caused by the longitudinal splitting of the pericarp during the drying process. Lipids composed 28.4% of the dry weight of Q. nigra and 5.7% of Q. alba dry weight. Neither individual fatty acids nor total fatty acid content exhibited definite patterns of change over the course of the experiment. The most prevalent saturated fatty acid in both species was palmitic acid, and the most common unsaturated fatty acid was generally oleic acid. Electron microscopy studies of Q. nigra showed cell wall trauma after 3 days of drying (moisture content 23%); by day 7, when moisture content had dropped to 15.6%, there was a definite dissolution of cytoplasmic density and a reduction of spherosome concentration. Quercusalba exhibited similar responses to drying, but cell wall integrity was maintained. Differential scanning calorimetry studies revealed strong relationships between onset and enthalpy values of all acorn tissues and percent germination, as did regressions involving moisture content and seed germination.

Study on the β1→α+β2 Transformation Kinetics of Ti-6Al-4V Alloy by DSC

2014 ◽  
Vol 508 ◽  
pp. 110-113
Author(s):  
Rong Hua Zhang ◽  
Biao Wu ◽  
Xiao Ping Zheng
Keyword(s):  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Phase Transformation ◽  
Cooling Rate ◽  
Volume Fraction ◽  
Avrami Exponent ◽  
Transformation Kinetics ◽  
Cooling Process ◽  
Scanning Calorimetry ◽  
Kinetics Of

The temperature and duration of β1→α+β2 transformation of Ti-6Al-4V alloy in cooling process were measured by differential scanning calorimetry, and transformation activation energy and Avrami exponent of β1→α+β2 were also calculated. The results show that the cooling rate is in the range of 在5～20°C/min, the transformation temperature and the transformation duration β1→α+β2 transformation of Ti-6Al-4V alloy decreased with the increasing cooling rate, its transformation activation energy decreased with the increasing phase transformation volume fraction, and Avrami exponent was between 1 and 2 at 660°C.

The Preparation and Characteristic Research of Keratin Powder Based on TCEP

2014 ◽  
Vol 1053 ◽  
pp. 438-443
Author(s):  
Jian Yong Liu ◽  
Jie Wang ◽  
Hao Ming Li
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Moisture Content ◽  
Helical Structure ◽  
Ftir Analysis ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Β Sheet ◽  
Melting Peak Temperature ◽  
Wool Keratin

In this paper, the wool was pretreated by TCEP (Tris (2-carboxyethyl) phosphine) a certain time, and then prepared wool keratin powder by mechanical lapping. The characteristics of the keratin powder carried out by Fourier transform infrared (FTIR) and Differential scanning calorimetry (DSC). From the FTIR analysis, TCEP first role in α-helical structure of wool, making its decline, and then acting on β-sheet. From the DSC analysis, the melting peak temperature of α-crystalline with the time of TCEP effect on wool, presenting the trend of first increased and then drophave. Dissolved the keratin powder in 88% formic acid, then keratin films were maded.The characteristics of the keratin films were measured, the moisture content of keratin film increases with the time of wool treated with TCEP. And the dissolution rate and ultimate strength in line with the change of FTIR and DSC analysis results.

scholarly journals Study on Spontaneous Combustion Tendency of Coals with Different Metamorphic Grade at Low Moisture Content Based on TPO-DSC

2019 ◽  
Author(s):  
Jiuyuan Fan ◽  
Gang Wang ◽  
Jiuling Zhang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Moisture Content ◽  
Spontaneous Combustion ◽  
Metamorphic Grade ◽  
Characteristic Parameters ◽  
Scanning Calorimetry ◽  
Temperature Programmed Oxidation ◽  
Influence Effect ◽  
Temperature Programmed ◽  
Open Coal

In the environments of all kinds open coal storage sites , mining-affected coalbeds, and goafs, parts of coal body at low moisture content (≤8%) are prone to spontaneous combustion under the influence of some external environmental factors. In order to examine the influence effect of low moisture content on the spontaneous combustion tendency of coals with different metamorphic grade, we conducted temperature programmed oxidation (TPO) experiment and differential scanning calorimetry (DSC) experiment to study the spontaneous combustion characteristics of coals with different metamorphic grade at four different low moisture content, and comparatively analyzed the change laws of the characteristic parameters of four different metamorphic grade coals at four different low moisture content. The experimental results indicate that: 1) Compared other low moisture content, anthracite and fat coal at low moisture content of 1.2% show stronger tendency to undergo spontaneous combustion, long flame coal and lignite at low moisture content of 3.4% and 5.6% are more prone to spontaneous combustion. 2) Four different metamorphic grade coals at low moisture content of 7.8% are less prone to spontaneous combustion; 3) Coals with different metamorphic grade have different tendency to undergo spontaneous combustion.

scholarly journals Resin-modified Glass-ionomer Setting Reaction Competition

2009 ◽  
Vol 89 (1) ◽  
pp. 82-86 ◽  
Author(s):  
D.W. Berzins ◽  
S. Abey ◽  
M.C. Costache ◽  
C.A. Wilkie ◽  
H.W. Roberts
Keyword(s):  
Differential Scanning Calorimetry ◽  
The Other ◽  
Glass Ionomer ◽  
Light Activation ◽  
Acid Base ◽  
Scanning Calorimetry ◽  
Setting Reaction ◽  
Resin Modified Glass Ionomer ◽  
Light Curing ◽  
Setting Mechanism

Resin-modified glass ionomers (RMGI) set by at least 2 mechanisms dependent upon reactant diffusion prior to gelation. Each reaction’s kinetics and setting mechanism may rely on and/or compete with the other. In this study, we investigated RMGI setting reaction interactions using differential scanning calorimetry (DSC) by varying light-cure initiation times. A RMGI was analyzed with isothermal and dynamic temperature scan DSC with light-curing occurring immediately, or at 5 or 10 minutes after mixing as well as without light-activation. Results show that as time allowed for the acid-base reaction increased, the light-activation polymerization exotherm decreased. Conversely, analysis of DSC data suggests that earlier light-activation may limit the acid-base reaction and result in a different structured material. During early RMGI development, acid-base and light-polymerization reactions compete with and inhibit one another.

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