scholarly journals Investigation of the films based on the uronate polysaccharides by the method of differential scanning calorimetry

2018 ◽  
Vol 12 (3) ◽  
Author(s):  
N. Коndratjuk ◽  
Ye. Pyvovarov ◽  
Т. Stepanova ◽  
Yu. Matsuk
Keyword(s):  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Calcium Ions ◽  
Total Concentration ◽  
Moisture Loss ◽  
Dynamic Mode ◽  
Scanning Calorimetry ◽  
Ionotropic Gelation ◽  
Complete Disintegration ◽  
Temperature Ranges

In this paper, the problem of studying of the films properties on the basis of uronate polysaccharides (sodium alginate and pectin low-esterified amidated), created on the principle of ionotropic gelation with the participation of calcium ions, has being considered. The purpose of the study is to determine the patterns of films formation based on the composition of the uronate polysaccharides, to determine their properties when heated and conditions of destruction or combustion. The thermophysical properties of the films in the temperature range 20–500°C were controlled by the method of differential scanning calorimetry in the dynamic mode. The temperature at which the loss of external and internal moisture is occurring have been determined. The temperatures when films are subjected to destruction have been founded. Thus, the mass loss of samples was noted in the following temperature ranges: 52–100°С and 40–100°С; the maximum moisture loss was noted at 83 and 85°C for specimens with a total concentration of uronate polysaccharides 2% and 3% respectively. Maximum external moisture losses were 6% and 9%; intra-linked moisture – 28.5 and 29% respectively. Complete disintegration of polymers occurs after 300 and 310°C for specimens with a total concentration of uronate polysaccharides 2% and 3% respectively. The investigation of the destraction temperatures of the above systems allows us to predict the principle of heat treatment of semi-finished products contained in films, created on the basis of the reaction of ionotropic gelation of polysaccharides and calcium ions.

scholarly journals Improved Processing and Properties for Polyphenylene Oxide Modified by Diallyl Orthophthalate Prepolymer

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2016
Author(s):  
Honghua Wang ◽  
Qilin Mei ◽  
Yujie Ding ◽  
Zhixiong Huang ◽  
Minxian Shi
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Phase Separation ◽  
Dilution Effect ◽  
Gradual Decrease ◽  
Gel Point ◽  
Dynamic Mode ◽  
Curing Process ◽  
Scanning Calorimetry ◽  
Polyphenylene Oxide

Diallyl orthophthalate (DAOP) prepolymer was investigated as a reactive plasticizer to improve the processability of thermoplastics. The rheology of blends of DAOP prepolymer initiated by 2,3-dimethyl-2,3-diphenylbutane (DMDPB) and polyphenylene oxide (PPO) was monitored during the curing process, and their thermal properties and morphology in separated phases were also studied. Differential scanning calorimetry (DSC) results showed that the cure degree of the reactively plasticized DAOP prepolymer was reduced with increasing PPO due to the dilution effect. The increasing amount of the DAOP prepolymer led to a gradual decrease in the viscosity of the blends and the rheology behavior was consistent with the chemical gelation of DAOP prepolymer in blends. This indicated that the addition of the DAOP prepolymer effectively improved processability. The phase separation occurring during curing of the blend and the transition from the static to dynamic mode significantly influences the development of the morphology of the blend corresponding to limited evolution of the conversion around the gel point.

scholarly journals Effect of Ca(OH)2 and Heat Treatment on The Physico-Chemical Properties of Bovine Bone Powder; a Material Useful for Medical, Catalytic, and Environmental Applications

2019 ◽  
Vol 26 (1) ◽  
pp. 114-119
Author(s):  
Naseer Ahmed KHAN ◽  
Mukhtiar AHMED ◽  
Naveed ul Hasan SYED ◽  
Matthew DREWERY
Keyword(s):  
Heat Treatment ◽  
Calcium Ions ◽  
Bone Matrix ◽  
Chemical Properties ◽  
Calcium Content ◽  
Bovine Bone ◽  
Physico Chemical ◽  
Bone Powder ◽  
Temperature Ranges ◽  
Oily Liquid

In this study the authors investigated the effect of alkali (Ca(OH)2) and heat treatment on the physico-chemical properties of bovine bone powder. For this purpose, raw and alkali treated samples were heated separately at temperatures of 400 °C, 600 °C, 800 °C, and 1000 °C. A combination of characterization techniques, such as TGA, XRD, N2-adsorbtion isotherms, and EDX were used. It was found that the boiling of cleaned solid pieces of bones in 2 molar Ca(OH)2 solution results in a mass loss of about 10 % (mainly discards oily liquid). TGA analysis affirms that the hydrocarbons of bone matrix are partially extractable (~ 10 %) in the boiling alkaline solution. The color of raw and treated bone samples remained similar, that is changing from yellowish white to grayish black before turning into white over temperatures ranging from 30 °C (room temperature), 400 – 600 °C, and 800 – 1000 °C, respectively. Moreover, XRD signatures were also comparable at unified temperature ranges, however, it was noted that carbonization due to heating engenders a significant change in the intensities of the x-ray reflections. Despite of having similarities, surface area of raw and treated bones at 400 °C, 600 °C and 800 °C were found to be different, indicative of a chemical interactions of calcium ions with bone. Quite interestingly, TGA, XRD, and N2-adsorbtion isotherms support the argument that a limited amount of calcium ions diffuses into the vacancies or interstitial sites of bone lattice. Furthermore, EDX analysis of the samples calcined at 1000 °C confirms that the Ca(OH)2 treatment increases the total calcium content of hydroxylapatite (inorganic part of bone matrix).

In vivo characterization of thermal stabilities of Aeropyrum pernix cellular components by differential scanning calorimetry

2007 ◽  
Vol 53 (9) ◽  
pp. 1038-1045 ◽  
Author(s):  
Igor Milek ◽  
Miha Črnigoj ◽  
Nataša Poklar Ulrih ◽  
Gönül Kaletunç
Keyword(s):  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Optical Data ◽  
Lag Phase ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Whole Cell ◽  
Whole Cells ◽  
Aeropyrum Pernix ◽  
Cellular Components

Revival studies of Aeropyrum pernix show that the viability of cells and cell recovery after heat treatment depends on the temperature of treatment. Differential scanning calorimetry (DSC) is used to analyze the relative thermal stabilities of cellular components of A. pernix and to identify the cellular components responsible for the observed lag phase and reduced maximum growth following a heat treatment. DSC thermograms show 5 visible endothermic transitions with 2 major transitions. DSC analysis of isolated crude ribosomes aids the assignment of the 2 major peaks observed in whole-cell thermograms to denaturation of ribosomal structures. A comparison of partial and immediate full rescan thermograms of A. pernix whole cells indicates that both major peaks represent irreversible thermal transitions. A DNA peak is also identified in the whole-cell thermogram by comparison with the optical data of isolated pure DNA. DNA melting is shown to be irreversible in dilute solution, whereas it is partially reversible in whole cells, owing at least in part, to restricted volume effects. In contrast to mesophilic organisms, hyperthermophilic A. pernix ribosomes are more thermally stable than DNA, but in both organisms, irreversible changes leading to cell death occur owing to ribosomal denaturation.

Synthesis of nanocomposite coating of electrodeposed amorphic layers of the Ni–P–W system

2020 ◽  
pp. 53-60
Author(s):  
A. V. Krasikov
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Phase Composition ◽  
Diffraction Analysis ◽  
Nanocomposite Coating ◽  
Nanocrystalline Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The processes of the formation of the nanocomposite coating of Ni–11.5% P–5%W were studied during the heat treatment of amorphous electrodeposited layers. Using the method of differential scanning calorimetry, the temperature of the onset of crystallization of the nanocrystalline phase Ni3P was determined. X-ray diffraction analysis showed that heat treatment produces Ni3P phosphides and, presumably, Ni5P2, the size of which, according to electron microscopy, is 5–50 nm. The influence of the duration of heat treatment on the phase composition and microhardness of coatings is investigated.

scholarly journals Evaluation of the Heat Inactivation of Escherichia coli and Lactobacillus plantarum by Differential Scanning Calorimetry

2002 ◽  
Vol 68 (11) ◽  
pp. 5379-5386 ◽  
Author(s):  
Jaesung Lee ◽  
Gönül Kaletunç
Keyword(s):  
Escherichia Coli ◽  
Heat Treatment ◽  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Lactobacillus Plantarum ◽  
Plate Count ◽  
Scanning Calorimetry ◽  
Whole Cells ◽  
E Coli ◽  
Thermal Stability Of

ABSTRACT Differential scanning calorimetry (DSC) is used to evaluate the thermal stability and reversibility after heat treatment of transitions associated with various cellular components of Escherichia coli and Lactobacillus plantarum. The reversibility and the change in the thermal stability of individual transitions are evaluated by a second temperature scan after preheating in the DSC to various temperatures between 40 and 130°C. The viability of bacteria after a heat treatment between 55 and 70°C in the DSC is determined by both plate count and calorimetric data. The fractional viability values based on calorimetric and plate count data show a linear relationship. Viability loss and the irreversible change in DSC thermograms of pretreated whole cells are highly correlated between 55 and 70°C. Comparison of DSC scans for isolated ribosomes shows that the thermal stability of E. coli ribosomes is greater than that of L. plantarum ribosomes, consistent with the greater thermal tolerance of E. coli observed from viability loss and DSC scans of whole cells.

scholarly journals Heat treatment of liquid egg yolk

2020 ◽  
Author(s):  
Emna Ayari ◽  
Csaba Németh ◽  
Karina Ilona Hidas ◽  
Adrienn Tóth ◽  
Dávid Láng ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Apparent Viscosity ◽  
Processing Time ◽  
Egg Yolk ◽  
Endothermic Peak ◽  
Scanning Calorimetry ◽  
New Methods ◽  
Egg Products

AbstractStarting from mechanical revolution, each day new methods and new equipment have emerged. Today, the Ultra Heat Treatment (UHT) is one of the important technologies that permits to the industry to reduce processing time while maintaining the same quality of the products. Egg and egg products are known as heat-sensitive products, so the UHT enables us to preserve their qualities after a heat treatment.Our aim is to study the effect of UHT treatment (approximately 67 °C for 190 s) on the Liquid Egg Yolk (LEY). For twenty-one days, the color and the apparent viscosity were measured every seven days, we also studied the damage of protein using DSC (Differential Scanning Calorimetry).Comparing the two graphs of DSC, the denaturation of protein is distinct. The endothermic peak decreased. This could be seen also on the rheological curves. The apparent viscosity is diminished from 231 mPa.s on the 1st day of storage to 224 mPa.s on 21st day. However, the treated LEY could be stored for longer period than the raw LEY.

Evaluation by Differential Scanning Calorimetry of the Effect of Acid, Ethanol, and NaCl on Escherichia coli

2005 ◽  
Vol 68 (3) ◽  
pp. 487-493 ◽  
Author(s):  
JAESUNG LEE ◽  
GÖNÜL KALETUNÇ
Keyword(s):  
Escherichia Coli ◽  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Cell Viability ◽  
Ribosomal Subunit ◽  
Scanning Calorimetry ◽  
Processing Technologies ◽  
Log Reduction ◽  
Minimal Reduction

The influence of acid, ethanol, and NaCl on the cellular components and inactivation of Escherichia coli were evaluated using differential scanning calorimetry. Cell viability was assessed using plate counting. The thermal stability for ribosomal subunit denaturation and the total apparent enthalpy decreased with increasing ethanol, salt, and acid concentrations. The reduction of the ribosomal subunit denaturation peak was the primary contributor to the decrease in the total apparent enthalpy. Thermograms indicated that even at concentrations at which less than a 0.4-log reduction of cell viability with a concomitant minimal reduction of total apparent enthalpy occurred, a decrease in onset temperature of ribosomal transition was evident. Acid treatments at pH 3 induced by HCl and by 0.4 M acetic acid caused the DNA denaturation temperature in vivo to decrease. Application of chemical treatment prior to heat treatment noticeably reduced the viability of E. coli cells at all the heat treatment temperatures (60, 62.5, and 65°C) compared with that of heat treatment alone, suggesting an increased sensitivity of bacteria to heat treatment. Differential scanning calorimetry in vivo can be used to assess the effectiveness of hurdles when thermal processing technologies with hurdles are designed.

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