scholarly journals Extending Cooling Rate Performance of Fast Scanning Chip Calorimetry by Liquid Droplet Cooling

2021 ◽  
Vol 11 (9) ◽  
pp. 3813
Author(s):  
Evgeny Zhuravlev ◽  
Jing Jiang ◽  
Dongshan Zhou ◽  
René Androsch ◽  
Christoph Schick
Keyword(s):  
Cooling Rate ◽  
Liquid Droplet ◽  
Large Samples ◽  
Chip Calorimetry ◽  
Different Temperatures ◽  
Temperature Ranges ◽  
Gas Cooling ◽  
The Common ◽  
Fast Scanning Chip Calorimetry ◽  
Cooling Technique

The liquid droplet cooling technique for fast scanning chip calorimetry (FSC) is introduced, increasing the cooling rate for large samples on a given sensor. Reaching higher cooling rates and using a gas as the cooling medium, the common standard for ultra-fast temperature control in cooling requires reducing the lateral dimensions of the sample and sensor. The maximum cooling rate is limited by the heat capacity of the sample and the heat exchange between the gas and the sample. The enhanced cooling performance of the new liquid droplet cooling technique is demonstrated for both metals and polymers, on examples of solidification of large samples of indium, high-density polyethylene (HDPE) and poly (butylene 2,6-naphthalate) (PBN). It was found that the maximum cooling rate can be increased up to 5 MK/s in room temperature environment, that is, by two orders of magnitude, compared to standard gas cooling. Furthermore, modifying the droplet size and using coolants at different temperatures provide options to adjust the cooling rate in the temperature ranges of interest.

scholarly journals Extending Cooling Rate Performance of Fast Scanning Chip Calorimetry by Liquid Droplet Cooling

2021 ◽  
Author(s):  
Evgeny Zhuravlev ◽  
Jing Jiang ◽  
Dongshan Zhou ◽  
René Androsch ◽  
Christoph Schick
Keyword(s):  
Cooling Rate ◽  
Liquid Droplet ◽  
Large Samples ◽  
Chip Calorimetry ◽  
Different Temperatures ◽  
Temperature Ranges ◽  
Gas Cooling ◽  
The Common ◽  
Fast Scanning Chip Calorimetry ◽  
Cooling Technique

The liquid droplet cooling technique for fast scanning chip calorimetry (FSC) is introduced, increasing the cooling rate for large samples on a given sensor. Reaching higher cooling rates and using a gas as the cooling medium, the common standard for ultra-fast temperature control in cooling, requires reducing the lateral dimensions of the sample and sensor. The maximum cooling rate is limited by the heat capacity of the sample and the heat exchange between the gas and the sample. The enhanced cooling performance of the new liquid droplet cooling technique is demonstrated for both metals and polymers, on examples of solidification of large samples of indium, high-density polyethylene (HDPE), and poly (butylene 2,6-naphthalate) (PBN). It was found that the maximum cooling rate can be increased up to 5 MK/s in room temperature environment, that is, by 2 orders of magnitude, compared to standard gas cooling. Furthermore, modifying the droplet size and using coolants at different temperatures provide options to adjust the cooling rate in the temperature ranges of interest.

Evaluation of Space Radiator Performance by Simulation of Infrared Emission

1988 ◽  
Vol 42 (1) ◽  
pp. 114-120 ◽  
Author(s):  
Koji Ohta ◽  
Robert T. Graf ◽  
Hatsuo Ishida
Keyword(s):  
Temperature Dependence ◽  
Cooling Rate ◽  
Liquid Droplet ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Fourth Power ◽  
Emissive Power ◽  
Different Temperatures ◽  
Effective Radiation ◽  
Total Emittance

The total performance of a droplet space radiator has been predicted by simulation of infrared emission spectra. Emission spectra for a droplet are simulated with the use of exact optical theory from the optical constant spectra of a low-molecular-weight silicone, which is a candidate for use as an emission medium of the radiator. Emissive power and total emittance are calculated from the simulated emission spectra for a droplet at different temperatures. It is found that the fourth-power temperature dependence of the emissive power of the blackbody and the temperature dependence of the emissivity inherent to the materials govern the emissive power of the droplet. The progressive decreases in temperature of a droplet and a droplet sheet in space are also simulated. A droplet with a diameter of 1 μm is predicted to cool from 500 K to 252 K in two seconds. The effects of the size of a droplet and the number density of the droplets in the sheet on the cooling rate are estimated. A smaller droplet is essential for obtaining effective radiation in the liquid droplet radiator. A dense cloud of the droplet sheet will retard the cooling rate of the droplets because of the reabsorption of the emitted light.

scholarly journals Crystallization of Random Metallocene-Catalyzed Propylene-Based Copolymers with Ethylene and 1-Hexene on Rapid Cooling

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2091
Author(s):  
Daniela Mileva ◽  
Jingbo Wang ◽  
René Androsch ◽  
Katalee Jariyavidyanont ◽  
Markus Gahleitner ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Metallocene Catalyst ◽  
Nucleating Agent ◽  
Random Copolymers ◽  
Rapid Cooling ◽  
Significant Difference ◽  
Chip Calorimetry ◽  
High Cooling Rates ◽  
Fast Scanning Chip Calorimetry

Propylene-based random copolymers with either ethylene or 1-hexene as comonomer, produced using a metallocene catalyst, were studied regarding their crystallization behaviors, with a focus on rapid cooling. To get an impression of processing effects, fast scanning chip calorimetry (FSC) was used in addition to the characterization of the mechanical performance. When comparing the comonomer type and the relation to commercial grades based on Ziegler–Natta-type catalysts, both an interaction with the catalyst-related regio-defects and a significant difference between ethylene and 1-hexene was observed. A soluble-type nucleating agent was found to modify the behavior, but to an increasingly lesser degree at high cooling rates.

scholarly journals Fast-Scanning Chip-Calorimetry Measurement of Crystallization Kinetics of Poly(Glycolic Acid)

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 891
Author(s):  
Yongxuan Chen ◽  
Kefeng Xie ◽  
Yucheng He ◽  
Wenbing Hu
Keyword(s):  
Crystallization Kinetics ◽  
Temperature Region ◽  
Glycolic Acid ◽  
Crystal Nucleation ◽  
Side Group ◽  
Half Time ◽  
Temperature Range ◽  
Chip Calorimetry ◽  
Kinetics Of ◽  
Fast Scanning Chip Calorimetry

We report fast-scanning chip-calorimetry measurement of isothermal crystallization kinetics of poly(glycolic acid) (PGA) in a broad temperature range. We observed that PGA crystallization could be suppressed by cooling rates beyond -100 K s−1 and, after fast cooling, by heating rates beyond 50 K s-1. In addition, the parabolic curve of crystallization half-time versus crystallization temperature shows that PGA crystallizes the fastest at 130 °C with the minimum crystallization half-time of 4.28 s. We compared our results to those of poly(L-lactic acid) (PLLA) with nearby molecular weights previously reported by Androsch et al. We found that PGA crystallizes generally more quickly than PLLA. In comparison to PLLA, PGA has a much smaller hydrogen side group than the methyl side group in PLLA; therefore, crystal nucleation is favored by the higher molecular mobility of PGA in the low temperature region as well as by the denser molecular packing of PGA in the high temperature region, and the two factors together decide the higher crystallization rates of PGA in the whole temperature range.

Modeling of Liquid-Liquid Demixing Curve in Lead-Zinc Binary System

2018 ◽  
Vol 18 ◽  
pp. 49-54
Author(s):  
Naceur Amel ◽  
Adjadj Fouzia
Keyword(s):  
Mathematical Model ◽  
Free Energy ◽  
Phase Separation ◽  
Binary System ◽  
Free Energies ◽  
Common Tangent ◽  
Different Temperatures ◽  
Lead Zinc ◽  
The Common ◽  
Zn Alloys

In this work we discussed the modeling of the demixing curve in the liquid state in the Lead – Zinc binary system. We are interested to recalculate the free energies relating on Pb-Zn alloys for several temperatures based on the thermodynamic data collected in the bibliography. This calculation allows us to trace the curve of phase separation from a program after obtaining the mole fractions corresponding to the common tangent to the curve of the free energy with two minima at different temperatures. To do this, we used the Matlab 7.1 as the programming language and the Redlich-Kister polynomial as a mathematical model of development. The results obtained are very satisfactory by comparing them with those of the bibliography.

scholarly journals Mineral Composition and Antioxidant Potential in the Common Poppy (Papaver rhoeas L.) Petal Infusions

2020 ◽  
Vol 199 (1) ◽  
pp. 371-381
Author(s):  
Janda Katarzyna ◽  
Jakubczyk Karolina ◽  
Kupnicka Patrycja ◽  
Bosiacki Mateusz ◽  
Gutowska Izabela
Keyword(s):  
Vitamin C ◽  
Mineral Content ◽  
Antioxidant Potential ◽  
Effect Of Temperature ◽  
Total Polyphenol ◽  
Spectrophotometric Methods ◽  
Inflammatory Conditions ◽  
Different Temperatures ◽  
The Common ◽  
Increasing Temperature

AbstractThe flowers of the common poppy are used for medicinal purposes, both internally and externally. They are reported to have antispasmodic and antitussive properties, to alleviate inflammatory conditions and soothe anxiety-related digestive problems. The aim of the study was to determine the antioxidant potential and the content of vitamin C, polyphenols, and minerals in infusions made from the petals of the common poppy at different temperatures. The infusions were made at various temperatures (25 °C, 70 °C, 80 °C, and 90 °C). The antioxidant potential and the content of polyphenols and vitamin C were determined by spectrophotometric methods. The mineral content was determined using the ICP-OES method. The total polyphenol content ranged from 135.2 to 137.24 ppm and that of vitamin C—from 15.47 to 15.78 mg/100 mL. The temperature of the water used to make the infusions did not appear to have a significant effect on these parameters. The temperature did, however, significantly affect the antioxidant potential of the infusions—the highest antioxidant activity (71.21% DPPH inhibition) was observed in the infusion prepared using water at 80 °C. The infusions included in the study contained a number of minerals. No significant effect of temperature was found for the content of K, Zn, Cu, Fe, and Ni in the infusions. On the other hand, the content of Ca in the infusions was significantly correlated with the increasing temperature of the water. It was concluded that poppy petal infusions may serve as a valuable dietary supplement, providing antioxidants and minerals required by the human body to function properly.

Steady-State Crystal Nucleation Rate of Polyamide 66 by Combining Atomic Force Microscopy and Fast-Scanning Chip Calorimetry

2020 ◽  
Vol 53 (13) ◽  
pp. 5560-5571 ◽  
Author(s):  
Rui Zhang ◽  
Evgeny Zhuravlev ◽  
Jürn W. P. Schmelzer ◽  
René Androsch ◽  
Christoph Schick
Keyword(s):  
Atomic Force Microscopy ◽  
Steady State ◽  
Nucleation Rate ◽  
Crystal Nucleation ◽  
Polyamide 66 ◽  
Force Microscopy ◽  
Atomic Force ◽  
Chip Calorimetry ◽  
Fast Scanning Chip Calorimetry

Seed germination at different temperatures and seedling emergence at different depths of Rhamnus spp

2014 ◽  
Vol 9 (5) ◽  
pp. 569-578 ◽  
Author(s):  
Hanan Aou-ouad ◽  
Hipólito Medrano ◽  
Ahmed Lamarti ◽  
Javier Gulías
Keyword(s):  
Seed Germination ◽  
Seedling Recruitment ◽  
Seedling Emergence ◽  
Burial Depth ◽  
Temperature Regimes ◽  
Mediterranean Shrubs ◽  
Different Temperatures ◽  
Temperature Ranges ◽  
Different Depths ◽  
Rhamnus Alaternus

AbstractRhamnus alaternus and R. ludovici-salvatoris, two Mediterranean shrubs with different geographic distributions, have shown important differences in seedling recruitment capacity. The objectives of this work were to determine the ability of these species to germinate seeds under different temperature ranges, as well as the capacity of seedlings to emerge from different burial depths, in order to better understand their regeneration processes. Two different experiments were performed. In the first one, seed germination was studied in Petri dishes and in the dark at different temperature regimes: a) 5–15°C, b) 10–20°C and c) 15–25°C (12h/12h). In the second experiment, seedling emergence capacity from different burial depths (0.5, 2 and 5 cm) was tested. R. ludovici-salvatoris showed a significantly higher final germination rates, a lower dormancy period, and average time response at 10–20°C than at other temperature ranges, although differences were much greater when seeds were subjected to the 5–15°C temperature regime. By contrast, R. alaternus did not show significant differences between treatments (5–15°C and 10–20°C) in germination behavior. Seedling emergence of both species was lower and slower when seeds were buried at 5 cm. However, R. ludovici-salvatoris always showed a lower seedling emergence capacity than R. alaternus at any burial depth. The low ability of R. ludovici-salvatoris to germinate seeds and emerge between 5–15°C, even from shallow depths, is discussed in relation to its low regeneration capacity and declining geographic distribution.

Thermal Reactor Synthesis of Nanoscale Ceramic Powders using Organosilazane Aerosols

1991 ◽  
Vol 249 ◽  
Author(s):  
Tongsan D. Xiao ◽  
Peter R. Strutt ◽  
Kenneth E. Gonsalves ◽  
V. Shankar
Keyword(s):  
Particle Size ◽  
Cooling Rate ◽  
Thermal Conversion ◽  
Thermal Reactor ◽  
Ceramic Powders ◽  
Powder Synthesis ◽  
Critical Feature ◽  
Ceramic Particles ◽  
Sic Ceramic ◽  
Gas Cooling

ABSTRACTThis investigation involves the thermal conversion of an organosilazane precursors into ultrafine ceramic particles. In this process, aerosols of a reactive organosilazane precursor, [CH3SiHNH]n n = 3 or 4, are injected into a hot furnace to obtain Si3N4/SiC ceramic powders. One critical feature examined in this process was the rapidity of the powder synthesis, in a reaction which involves (i) elimination of ligand groups, (ii) formation of ceramic species, and (iii) condensation of ceramic species into ultrafine ceramic particles. Accompanying studies a model has been formulated to determine the gas cooling rate and particle size.

scholarly journals Determination of the effect of exposure conducted in KOH solutions at different temperatures on the properties of electrochromic Ni(OH)2-PVA films

2021 ◽  
Vol 4 (6(112)) ◽  
pp. 60-66
Author(s):  
Valerii Kotok ◽  
Vadym Kovalenko ◽  
Rovil Nafeev ◽  
Volodymyr Verbitskiy ◽  
Elena Lominoga ◽  
...  
Keyword(s):  
Treatment Temperature ◽  
Electrochemical Activity ◽  
Operating Conditions ◽  
Electrochromic Device ◽  
Electrochemical Characteristics ◽  
Composite Electrodes ◽  
Hot Climate ◽  
Different Temperatures ◽  
Temperature Ranges ◽  
Electrochemical Cycling

To determine the effect of exposure of film composite electrodes based on Ni(OH)2-polyvinyl alcohol to an alkaline solution at high temperatures on the electrochromic and electrochemical characteristics, a series of films was obtained. The films were obtained on a glass substrate coated with fluorine-doped tin oxide. The coating of the substrates was carried out by the cathodic template method under the same conditions. The resulting precipitates were treated by keeping them in an alkali solution at different temperatures: 30, 40, 50, 60, and 70 °C for 8 hours, thereby simulating the operating conditions of an electrochromic device in a hot climate. It was found that the exposure temperature directly affected the electrochemical and electrochromic properties of the treated films. In this case, the cyclic volt-ampere curves showed a decrease in the peak values of the current densities and a lower rate of establishment of characteristics with an increase in the treatment temperature. At a maximum treatment temperature of 70 °C, the properties of the film significantly changed towards deterioration. According to the results of the experiments, three temperature ranges of treatment were identified. The first one was in the range up to 40 °C, in which the films showed significant electrochromic and electrochemical activity after treatment. The second interval was between 40 and 60 °C, in which the coatings showed a reversible deterioration in electrochromic and electrochemical activity. After treatment in the second interval, the films gradually restored their performance during electrochemical cycling. The third interval was from 70 °C and above. The films treated in this temperature range irreversibly lost their electrochemical and electrochromic activity. The study also proposed mechanisms to explain changes in the characteristics of electrodes during treatment, as well as possible ways to combat temperature degradation.

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