scholarly journals Thermal Properties of the Collagen of Jellyfish (Aurelia Coerulea) and their Relation to its Thermal Behaviour

1972 ◽  
Vol 25 (6) ◽  
pp. 1361 ◽  
Author(s):  
BJ Rigby ◽  
M Hafey
Keyword(s):  
Thermal Properties ◽  
Melting Point ◽  
Melting Temperature ◽  
Thermal Behaviour ◽  
Environmental Temperature ◽  
General Assumption ◽  
General Statement ◽  
Temperature Relation ◽  
Upper Limit ◽  
Melting Tempera Ture

It has been reported elsewhere (Rigby 1968a, 1968b) that for a number of poikilotherms sudden changes occur in physiological behaviour at temperatures which are the same as the melting temperature of their molecular collagen. A more general statement, which includes the above observations, is that the upper limit of the environmental temperature for an animal corresponds with the melting tempera. ture of its molecular collagen. A number of workers have contributed to this idea and details may be found in Rigby (1968a). It is not suggested that collagen is uniquely involved in these events, although this may be so. No doubt other body proteins are altered at the same time. The useful point is that collagen is one of the few easily prepared body proteins with a characteristic melting point, and as such can serve as an indicator in studies concerned with the temperature relation of poikilotherms. For example, animals, which can be adapted to reproduce at higher or lower temperatures than is usual for them, may produce a collagen which shows a parallel alteration in its melting temperature. Such an experiment would afford a test of the general assumption that the constitution and properties of a protein are determined only by genetic coding (see also Ruda1l1968).

Effects of Molecular Weight of Chitosan on the Biodegradability and Thermal Properties of Polybutylene Succinate/Chitosan Composites

2018 ◽  
Vol 775 ◽  
pp. 26-31
Author(s):  
Sukantika Manatsittipan ◽  
Kamonthip Kuttiyawong ◽  
Kazuo Ito ◽  
Sunan Tiptipakorn
Keyword(s):  
Molecular Weight ◽  
Weight Loss ◽  
Thermal Properties ◽  
Water Absorption ◽  
Melting Temperature ◽  
Microbial Degradation ◽  
Decomposition Temperature ◽  
Molecular Weights ◽  
Significant Difference ◽  
Polybutylene Succinate

In this study, the biodegradability and thermal properties the composites of polybutylene succinate (PBS) and chitosan of different molecular weights (Mn = 104,105, and 106 Da) were prepared at chitosan contents of 0-10 wt%. After 10 days of microbial degradation, the results show that the amount of holes from degradation was increased with either decreasing Mn or increasing chitosan contents. However, the size of holes was increased with increasing Mn and chitosan contents. The results from Differential Scanning Calorimeter (DSC) present that the melting temperature (Tm) of PBS was decreased with increasing chitosan contents. Moreover, there was no significant difference between Tm of the composites with different Mn of chitosan. From the TGA thermograms, the decomposition temperature at 10% weight loss (Td10) was decreased with increasing chitosan contents. Moreover, the water absorption of PBS/chitosan composites was increased with increasing Mn and content of chitosan.

scholarly journals Brazilian gutta-percha points. Part II: thermal properties

2007 ◽  
Vol 21 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Cláudio Maniglia-Ferreira ◽  
Eduardo Diogo Gurgel-Filho ◽  
João Batista Araújo Silva Jr ◽  
Regina Célia Monteiro de Paula ◽  
Judith Pessoa Andrade Feitosa ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Physical Properties ◽  
Ambient Temperature ◽  
Amorphous Phase ◽  
Thermal Behaviour ◽  
Chemical Structure ◽  
Scanning Calorimetry ◽  
Gutta Percha ◽  
Thermal Manipulation

This study was undertaken to explore the effect of heating on gutta-percha, analyzing the occurrence of endothermic peaks corresponding to the transformation that occurs in the crystalline structure of the polymer during thermal manipulation. This study also seeked to determine the temperature at which these peaks occur, causing a transformation from the beta- to the alpha-form, and from the alpha- to the amorphous phase. Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP, Dentsply FM) and pure gutta-percha (control) were analysed using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The transition temperatures were determined and analysed. With the exception of Dentsply 0.04 and Dentsply 0.06, the majority of the products showed thermal behaviour typical of beta-gutta-percha, with two endothermic peaks, exhibiting two crystalline transformations upon heating from ambient temperature to 130°. Upon cooling and reheating, few samples presented two endothermic peaks. It was concluded that heating dental gutta-percha to 130°C causes changes to its chemical structure which permanently alter its physical properties.

scholarly journals MODELLING THE MELTING TEMPERATURE OF A LIPID‐BASED CRITICAL TEMPERATURE INDICATOR: A COMPARISION BETWEEN SIMPLEX-LATTICE AND SIMPLEX-CENTROID DESIGNS

2018 ◽  
Vol 35 (2) ◽  
Author(s):  
KARINE CRISTINE KAUFMANN ◽  
ODINEI HESS GONÇALVES ◽  
EVANDRO BONA ◽  
FERNANDA VITÓRIA LEIMANN
Keyword(s):  
Critical Temperature ◽  
Melting Point ◽  
Melting Temperature ◽  
Predictive Ability ◽  
Ternary Mixtures ◽  
Lipid Mixture ◽  
Color Changes ◽  
Lattice Design ◽  
Simplex Lattice ◽  
Improved Model

Critical temperature indicators (CTI) find applications in food industry in cases when defrost may not occur or a specific temperature may not be reached, , indicating changes through visual changes, such as melting, color changes, etc. Lipid mixtures are promising candidates to formulate CTI since the final melting point of the mixture may be manipulated by the proportion of each lipid. In this work a lipid mixture consisting of stearic acid, lard and peanut oil was used to develop a CTI mixture. Simplex-lattice and Simplex-centroid experimental designs were compared to modelling the melting temperature of the lipid mixture. Addition of axial points to the experimental design improved predictive ability of the models while the inclusion of inverse terms was necessary to improve models accuracy. Simplex-lattice design presented an improved ability to predict the melting point of binary mixtures, while the simplex-centroid design resulted in an improved model for predicting melting point of the ternary mixtures

scholarly journals How Atoms of Polycrystalline Nb 20.6 Mo 21.7 Ta 15.6 W 21.1 V 21.0 refractory High-Entropy Alloys Rearrange during the Melting Process

2021 ◽  
Author(s):  
Shin-Pon Ju ◽  
Chen-Chun Li
Keyword(s):  
Molecular Dynamics ◽  
Melting Point ◽  
Single Crystal ◽  
Melting Temperature ◽  
Md Simulation ◽  
Melting Process ◽  
Structural Rearrangement ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Melting Mechanism

Abstract The melting mechanism of single crystal and polycrystalline Nb 20.6 Mo 21.7 Ta 15.6 W 21.1 V 21.0 RHEAs was investigated by the molecular dynamics (MD) simulation using the 2NN MEAM potential. For the single crystal RHEA, the density profile displays an abrupt drop from 11.25 to 11.00 g/cm 3 at temperatures from 2910 to 2940 K, indicating all atoms begin significant local structural rearrangement. For polycrystalline RHEAs, a two-stage melting process is found. In the first melting stage, the melting of the grain boundary (GB) regions firstly occurs at the pre-melting temperature, which is relatively lower than the corresponding system-melting point. At the pre-melting temperature, most GB atoms have enough kinetic energies to leave their equilibrium positions, and then gradually induce the rearrangement of grain atoms close to GB. In the second melting stage at the melting point, most grain atoms have enough kinetic energies to rearrange, resulting in the chemical short-ranged order (CSRO) changes of all pairs.

Thermal Properties Analysis of Several N-Alkanes Eutectic Mixtures Applied in Building Envelopes

2012 ◽  
Vol 512-515 ◽  
pp. 3007-3010
Author(s):  
Jing Yu Huang ◽  
Shi Lei Lv ◽  
Chen Xi Zhang ◽  
Zhi Wei Wang
Keyword(s):  
Thermal Properties ◽  
Melting Temperature ◽  
Latent Heat ◽  
Heat Storage ◽  
Eutectic Mixture ◽  
Scanning Calorimetry ◽  
Latent Heat Storage ◽  
Building Envelopes ◽  
Eutectic Mixtures ◽  
Change Material

This study focuses on the preparation, thermal properties of alkanes eutectic mixtures (n-Octadecane/n-Eicosane, n-Octadecane/n-Docosane and n-Heptadecane /n-Eicosane) as candidate phase change material (PCM) for low temperature latent heat storage systems in building envelopes. Their melting temperature and latent heat were tested by Differential scanning calorimetry (DSC). The testing values were closed to calculation values of accepted theory that ensured the reliability of those datas. The results indicated n-Octadecane/n-Docosane eutectic mixture was more promising PCM for buildings in terms of melting temperature (25.3°C) and latent heat values of melting (158.2J/g).

The Gallium Melting-Point Standard: A Determination of the Liquid—Solid Equilibrium Temperature of Pure Gallium on the International Practical Temperature Scale of 1968

1977 ◽  
Vol 23 (4) ◽  
pp. 719-724 ◽  
Author(s):  
Donald D Thornton
Keyword(s):  
Melting Point ◽  
Melting Temperature ◽  
Temperature Scale ◽  
Equilibrium Temperature ◽  
Melting Range ◽  
Practical Temperature ◽  
Practical Temperature Scale ◽  
Gallium Melting Point

Abstract The sharpness and reproducibility of the gallium melting point were studied, and the melting temperature of gallium in terms of IPTS-68 was determined. Small melting-point cells designed for use with thermistors are described. Nine gallium cells including three levels of purity were used in 68 separate determinations of the melting point. The melting point of 99.99999% pure gallium in terms of IPTS-68 is found to be 29.7714 ± 0.0014 °C; the melting range is less than 0.0005 °C and is reproducible to ±0.0004 °C.

Synthese, Struktur und thermisches Verhalten von Thiophosphorsäuretriamid SP(NH2)3 [1] / Synthesis, Structure, and Thermal Behaviour of Phosphorothionic Triamide SP(ΝΗ2)3 [1]

1989 ◽  
Vol 44 (8) ◽  
pp. 942-945 ◽  
Author(s):  
Wolfgang Schnick
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Thermal Properties ◽  
Single Crystal ◽  
Melting Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Ray Methods ◽  
Single Bonds

Phosphorothionic triamide SP(NH2)3 is obtained by slow addition of SPCl3 dissolved in dry CH2Cl2 to a satured solution of NH3 in CH2Cl2 at —50°C. Ammonium chloride is removed from the resulting precipitate by treatment with HNEt2 followed by extraction with CH2Cl2. Coarse crystalline SP(NH2)3 is obtained after recrystallization from dry methanol. The crystal structure of SP(NH2)3 has been determined by single crystal X-ray methods (Pbca; a = 922.3(1), b = 953.8(1), c = 1058.4(2) pm, Z = 8). In the crystals the molecules show non-crystallographic point symmetry C8. The P—S bond (195.4(1) pm) is slightly longer than in SPCl3. From P—N bond lengths of about 166 pm a significant electrostatic strengthening of the P—N single bonds is assumed. Weak intermolecular hydrogen bonding interactions (N —H · · · N ≥ 329.5 pm; N — H · · · S ≥ 348.3 pm) are observed.Investigation of thermal properties shows a melting temperature of 115°C for SP(NH2)3. According to combined DTA/TG and MS investigations above this temperature the compound decomposes by evolution of H2S and NH3 to yield amorphous phosphorus(V)nitride.

Irradiation of poly(l-lactide) biopolymer reinforced with functionalized MWCNTs

RSC Advances ◽  
2015 ◽  
Vol 5 (68) ◽  
pp. 55544-55549 ◽  
Author(s):  
Ali Nabipour Chakoli ◽  
Jinmei He ◽  
Maryam Amirian Chayjan ◽  
Yudong Huang ◽  
Baode Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Properties ◽  
Melting Point ◽  
Irradiation Effect ◽  
Mechanical And Thermal Properties ◽  
Functionalized Carbon Nanotubes ◽  
Functionalized Mwcnts

The γirradiation increases the modulus and strength, decreases the melting point of poly(l-lactide) during sterilization. The functionalized carbon nanotubes accelerate the irradiation effect on mechanical and thermal properties of poly(l-lactide).

Influence of Refused Glass on Thermal Properties of Municipal Waste

2016 ◽  
Vol 832 ◽  
pp. 23-30
Author(s):  
Kateřina Žurková ◽  
Karla Kryštofová ◽  
Helena Raclavská ◽  
Hana Škrobánková
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Czech Republic ◽  
Melting Point ◽  
Fossil Fuels ◽  
Alternative Fuel ◽  
Municipal Waste ◽  
Waste To Energy ◽  
Muffle Furnace ◽  
Cause Of Formation

It is important to reduce the amount of municipal waste deposited in landfills, Czech Republic, therefore, puts more emphasis on the recovery of mixed municipal waste, which oblige and EU regulations. Production of solid alternative fuel that is suitable also due to less consumption of fossil fuels, is one of the uses of mixed municipal waste (Waste to Energy). A relatively high proportion of glass in mixed municipal waste is a major problem in the production of solid alternative fuel. The glass contained in the solid alternative fuel can be the cause of formation incrusts on heat transfer surfaces in combustion plants. For all examined types of glass, it was found that the melting temperature of the muffle furnace was 750 ° C. When using the method (ISO 540) for determining the temperature of softening , melting and flow showed no effect of the amount of glass in the ash, but the melting point was significantly higher (around 1,200 °C).

A note on the melting-point of paraffins and fatty acids

1938 ◽  
Vol 34 (3) ◽  
pp. 459-464 ◽  
Author(s):  
E. B. Moullin
Keyword(s):  
Fatty Acids ◽  
Melting Point ◽  
Melting Temperature ◽  
Smooth Curve ◽  
Melting Points ◽  
Normal Paraffin ◽  
Simple Interpretation

The purpose of this note is to draw attention to a certain correspondence between the melting-points of normal paraffins and of fatty acids and to indicate a simple interpretation of this phenomenon. If the number of carbon atoms in a normal paraffin is plotted against the corresponding melting temperature, all the points in the diagram lie very close to a smooth curve drawn among them. If a similar diagram is made for the fatty acids, the points corresponding to an even number of carbon atoms lie on a curve of the same character as that found for paraffins. The points for an odd number of carbon atoms lie on a separate but similar curve, exemplifying the well-known alternation property.

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