scholarly journals Mathematical modeling of the effect of temperature on the activity and thermal stability of the inulinase of Kluyveromyces marxianus NRRL Y- 7571

2015 ◽  
pp. 303-312
Author(s):  
Jesús Diestra Balta ◽  
Lucas Margarito Aguilar ◽  
Roberto Vega Paulino ◽  
Augusto Castillo Calderón
Keyword(s):  
Mathematical Modeling ◽  
Thermal Stability ◽  
Kluyveromyces Marxianus ◽  
Effect Of Temperature ◽  
Thermal Stability Of

scholarly journals Effect of High Temperature on the Electrochemical and Optical Properties of Emeraldine Salt Doped with DBSA and Sulfuric Acid

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Salma Gul ◽  
Anwar-ul-Haq Ali Shah ◽  
Salma Bilal
Keyword(s):  
Thermal Stability ◽  
Cyclic Voltammetry ◽  
Sulfuric Acid ◽  
Effect Of Temperature ◽  
Visible Spectroscopy ◽  
Emeraldine Salt ◽  
Higher Temperature ◽  
Stability Effect ◽  
Thermal Stability Of ◽  
Comprehensive Study

A comprehensive study of thermally treated polyaniline in its emeraldine salt form is presented here. It offers an understanding of the thermal stability of the polymer. Emeraldine salt was prepared by a novel emulsion polymerization pathway using dodecylbenzene sulfonic acid and sulfuric acid together as dopants. The effect of temperature and heating rate on the degradation of this emeraldine salt was studied via thermogravimetric analysis. The thermally analyzed sample was collected at various temperatures, that is, 250, 490, 500, and 1000°C. The gradual changes in the structure of the emeraldine salt were followed through cyclic voltammetry, Fourier transform infrared spectroscopy, and ultraviolet-visible spectroscopy. Results demonstrate that emeraldine salt shows high thermal stability up to 500°C. This is much higher working temperature for the use of emeraldine salt in higher temperature applications. Further heat treatment seems to induce deprotonation in emeraldine salt. Cyclic voltammetry and ultraviolet-visible spectroscopy revealed that complete deprotonation takes place at 1000°C where it loses its electrical conductivity. It is interesting to note that after the elimination of the dopants, the basic backbone of emeraldine salt was not destroyed. The results reveal that the dopants employed have a stability effect on the skeleton of emeraldine salt.

THE EFFECTS OF TEMPERATURE UPON PANCREATIC AMYLASE IN SELECTED REPTILES AND AN AMPHIBIAN

1967 ◽  
Vol 45 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Yvette Abrahamson ◽  
Michael Maher
Keyword(s):  
Thermal Stability ◽  
Amylase Activity ◽  
Effect Of Temperature ◽  
Maximum Temperature ◽  
Pancreatic Amylase ◽  
Optimum Temperature ◽  
Preferred Temperatures ◽  
Effects Of Temperature ◽  
Subcellular Level ◽  
Thermal Stability Of

The effect of temperature on pancreatic amylase was studied on three species of reptiles and one amphibian. Pancreata were removed from the animals, homogenized, and assayed for amylase activity by the Caraway procedure. Assays were conducted at various temperatures to determine the optimum temperature of activity and the maximum temperature for thermal stability of pancreatic amylase. It appears that between reptiles and amphibians, and also among species of reptiles, there are thermally dependent differences at the subcellular level which are similar to the differences in the preferred temperatures of the animals.

Effect of ZnO Nano-Particles on The Dielectric Relaxation Behavior and Thermal Stability of Polycarbonate Host

2011 ◽  
Vol 24 (6) ◽  
pp. 837-852 ◽  
Author(s):  
A.A. Al Jaafari ◽  
A.S. Ayesh
Keyword(s):  
Thermal Stability ◽  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Zno Nanoparticles ◽  
Relaxation Behavior ◽  
Nano Particles ◽  
Effect Of Temperature ◽  
Frequency Range ◽  
Dielectric Relaxation Behavior ◽  
Thermal Stability Of

The influence of ZnO nanoparticles on the dielectric properties, dielectric relaxation behavior, and thermal stability of PC host was investigated at different ZnO nanoparticles concentration. The dielectric study was carried out over a frequency range from 500 Hz up to 1 MHz as a function of ZnO concentration. Results obtained from the best fitting of relative permittivity data with Yan and Rhodes model reveal that the dielectric relaxation is not a single relaxation process and there are two values of relaxation time for each nanocomposite at room temperature and domain frequency range. Furthermore, addition of ZnO nanoparticles to PC host changes the dielectric properties of PC, mainly, increases relative permittivity, dielectric loss, and AC conductivity while decreases the impedance values of PC host. Moreover, effect of temperature on AC conductivity of ZnO-PC nanocomposites at 1 kHz was also considered. Besides, dielectric relaxation behavior of PC was investigated at 165°C (above the glass transition temperature of PC) in the domain frequency range. At this elevated temperature (165°C), dielectric loss data shows a single relaxation peak (α-relaxation) in the domain frequency range and was successfully fitted with Debye equation. Also, it was found that as the content of ZnO nanoparticles increases in the PC host the frequency of the peak maximum ( fmax) shifts toward higher frequency value and as a result decreases the value of relaxation time. Additionally, this study shows that the isothermal effect of ZnO nano particles on the α-relaxation of PC host is similar to the effect of temperature. Both of them have a linear dependence with ln( fmax). Furthermore, addition of ZnO nanoparticles to PC host will decrease the thermal stability and glass transition temperature of PC host. Finally, there is a strong evidence from the obtained dielectric and thermal results that addition of ZnO nanoparticles to PC host will highly enhance the chain mobility and also increase the polar character of PC host.

scholarly journals Thermal Stability of 0.9% Sodium Chloride IV Fluid exposed to Short- and Long-Term Extreme Conditions

2020 ◽  
Author(s):  
Mohammed Akkbik ◽  
Mohamed Izham Mohamed Ibrahim ◽  
Mohammad Diab ◽  
Ayad Moslih ◽  
Ahmed Makhlouf ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Sodium Chloride ◽  
Normal Saline ◽  
Real Life ◽  
Exchange Chromatography ◽  
Effect Of Temperature ◽  
Long Term Study ◽  
Short And Long Term ◽  
Thermal Stability Of

Purpose: 0.9% sodium chloride IV fluid (normal saline) is critical in a clinical setting and may save lives. Data on thermal stability of normal saline, in out-of-hospital settings, are lacking. The purpose of this study was to evaluate the effect of temperature on normal saline stability. Method: Normal saline provided in flexible plastic containers (Qatar Pharma, BA:1929013008, n=96) were stored at constant temperature of 22, 50, or 70°C, and at cyclic temperature of 70°C for 8 hours and 22°C for 16 hours for a period up to 28 days. The containers were sampled at 0, 12, 24, 48 and 72 hours and at 1, 2, 3, and 4 weeks in the short- and long-term study, respectively. Fluid inside containers was evaluated for discoloration, turbidity, bulging, and pH. A 1 mL of normal saline was withdrawn from each container and stored at 4°C until analysis. A 20 µL was diluted in 12 mL distilled water to be injected into ion exchange chromatography instrument (Metrohm, 850 Professional IEC) for the measurement of sodium and chloride levels. Results: Discoloration or turbidity of normal saline fluid was not observed at any temperature or exposure period. The container slightly bulged at 50˚C and largely bulged at 70˚C & cyclic. The pH was 5.59±0.08 at 22˚C, 5.73±0.04 at 50˚C, 5.86±0.02 at 70˚C and 5.79±0.03 at cyclic. Remaining sodium and chloride levels ranged from 100.2±0.26% to 111.27±4.22% and from 99.04±0.76 to 110.95±2.62%, respectively. Conclusion: Normal saline containers are stable up to 4 weeks under simulated constant and cyclic high temperatures. Storage in the cabinet of ambulance vehicles during hot summer season in an arid country like Qatar is to be assessed in real-life conditions.

scholarly journals Structure and Thermal Stability of wtRop and RM6 Proteins through All-Atom Molecular Dynamics Simulations and Experiments

2021 ◽  
Vol 22 (11) ◽  
pp. 5931
Author(s):  
Maria Arnittali ◽  
Anastassia N. Rissanou ◽  
Maria Amprazi ◽  
Michael Kokkinidis ◽  
Vagelis Harmandaris
Keyword(s):  
Molecular Dynamics ◽  
Thermal Stability ◽  
Structural Integrity ◽  
Md Simulations ◽  
Effect Of Temperature ◽  
Key Factors ◽  
Loop Region ◽  
Dynamics Simulations ◽  
Experimental Findings ◽  
Thermal Stability Of

In the current work we study, via molecular simulations and experiments, the folding and stability of proteins from the tertiary motif of 4-α-helical bundles, a recurrent motif consisting of four amphipathic α-helices packed in a parallel or antiparallel fashion. The focus is on the role of the loop region in the structure and the properties of the wild-type Rop (wtRop) and RM6 proteins, exploring the key factors which can affect them, through all-atom molecular dynamics (MD) simulations and supporting by experimental findings. A detailed investigation of structural and conformational properties of wtRop and its RM6 loopless mutation is presented, which display different physical characteristics even in their native states. Then, the thermal stability of both proteins is explored showing RM6 as more thermostable than wtRop through all studied measures. Deviations from native structures are detected mostly in tails and loop regions and most flexible residues are indicated. Decrease of hydrogen bonds with the increase of temperature is observed, as well as reduction of hydrophobic contacts in both proteins. Experimental data from circular dichroism spectroscopy (CD), are also presented, highlighting the effect of temperature on the structural integrity of wtRop and RM6. The central goal of this study is to explore on the atomic level how a protein mutation can cause major changes in its physical properties, like its structural stability.

scholarly journals Device for investigating thermal stability of characteristics of voltage-to-frequiency converters

2021 ◽  
pp. 9-16
Author(s):  
V. A. Zavadsky ◽  
R. Yu. Kharchenko ◽  
S. M. Dranchuk ◽  
V. I. Tsatsko
Keyword(s):  
Thermal Stability ◽  
Mechanical Stress ◽  
Frequency Converter ◽  
Temperature Stability ◽  
Automatic Measurement ◽  
Effect Of Temperature ◽  
Frequency Converters ◽  
Wide Range ◽  
Output Characteristics ◽  
Thermal Stability Of

The article presents the research results on a device for automatic measurement of the temperature stability of the output characteristics of voltage-to-frequency converters. The device can be used to measure mechanical stresses in the ship's hull. The main source of information on the state of the mechanical stress on the hull of the ship is the integrated monitoring system. Monitoring methods are based on measuring the frequency of the output signals from the sensors based on strain gages, which have a wide scatter of values for parameters and characteristics and depend on external factors. A possible solution to this problem is to use a device that would convert the analog sensor signal into a more noise-immune signal of another type, for example, voltage-to-frequency converter. It is for such systems based on synchronous integrated converters that the authors have developed a device for automatic measurement of the temperature stability of the output characteristics of frequency converters. Such device can measure the thermal stability of the convertor automatically, which makes it possible to analyze the effect of temperature on the output characteristics of the converter and to experimentally study the sensors in a wide range of operating temperatures (from room temperature to 70℃). The study of the thermal stability of the characteristics of such sensors made it possible to confirm the quality of its electronic components and to determine which parameters need to be adjusted. The device is a set of units, one of them being a control circuit based on the ATmega-16 RISC microcontroller. This design and the developed algorithm for the device operation makes it possible to determine the output frequency with a high accuracy (with a measurement time of 1 sec, the accuracy reaches 0.05%). The developed device allows finding the ways to increase the thermal stability of mechanical stress sensors based on integral converters.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

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