Calorimetric analysis of the crystallization of PBT considering the dynamic cooling condition of real processing

AbstractAim of the present study is to analyze thermal events occurring during cryoablation. Different bovine liver samples underwent freezing cycles at different cooling rate (from 0.0075 to 25 K/min). Ice onset temperature and specific latent heat capacity of the ice formation process were measured according to differential scanning calorimetry signals. A computational model of the thermal events occurring during cryoablation was compiled using Neumann’s analytical solution. Latent heat (#1 = 139.8 ± 7.4 J/g, #2 = 147.8 ± 7.9 J/g, #3 = 159.0 ± 4.1 J/g) of all liver samples was independent of the ice onset temperature, but linearly dependent on the water content. Ice onset temperature was proportional to the logarithm of the cooling rate in the range 5 ÷ 25 K/min (#3a = − 12.2 °C, #3b = − 16.2 °C, #3c = − 6.6 °C at 5K/min; #3a = − 16.5 °C, #3b = − 19.3 °C, #3c = − 11.6 °C at 25 K/min). Ice onset temperature was associated with both the way in which the heat involved into the phase transition was delivered and with the thermal gradient inside the tissue. Ice onset temperature should be evaluated in the early phase of the ablation to tailor cryoenergy delivery. In order to obtain low ice trigger temperatures and consequent low ablation temperatures a high cooling rate is necessary.

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Experimental Comparison of Innovative Composite Sorbents for Space Heating and Domestic Hot Water Storage

Crystals ◽

10.3390/cryst11050476 ◽

2021 ◽

Vol 11 (5) ◽

pp. 476

Author(s):

Vincenza Brancato ◽

Larisa G. Gordeeva ◽

Angela Caprì ◽

Alexandra D. Grekova ◽

Andrea Frazzica

Keyword(s):

Silica Gel ◽

Xrd Analysis ◽

Complete Characterization ◽

Operating Conditions ◽

Hot Water ◽

Experimental Comparison ◽

Space Heating ◽

Calorimetric Analysis ◽

Domestic Hot Water ◽

Composite Sorbents

In this study, the development and comparative characterization of different composite sorbents for thermal energy storage applications is reported. Two different applications were targeted, namely, low-temperature space heating (SH) and domestic hot water (DHW) provision. From a literature analysis, the most promising hygroscopic salts were selected for these conditions, being LiCl for SH and LiBr for DHW. Furthermore, two mesoporous silica gel matrixes and a macroporous vermiculite were acquired to prepare the composites. A complete characterization was performed by investigating the porous structure of the composites before and after impregnation, through N2 physisorption, as well as checking the phase composition of the composites at different temperatures through X-ray powder diffraction (XRD) analysis. Furthermore, sorption equilibrium curves were measured in water vapor atmosphere to evaluate the adsorption capacity of the samples and a detailed calorimetric analysis was carried out to evaluate the reaction evolution under real operating conditions as well as the sorption heat of each sample. The results demonstrated a slower reaction kinetic in the vermiculite-based composites, due to the larger size of salt grains embedded in the pores, while promising volumetric storage densities of 0.7 GJ/m3 and 0.4 GJ/m3 in silica gel-based composites were achieved for SH and DHW applications, respectively.

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Sedimentary Clays as Geopolymer Precursor

International Journal of Engineering Research in Africa ◽

10.4028/www.scientific.net/jera.39.97 ◽

2018 ◽

Vol 39 ◽

pp. 97-111

Author(s):

F. Mostefa ◽

Nasr Eddine Bouhamou ◽

H.A. Mesbah ◽

Salima Aggoun ◽

D. Mekhatria

Keyword(s):

Sodium Hydroxide ◽

Mineralogical Composition ◽

Cementitious Materials ◽

Raw Material ◽

X Ray Diffraction ◽

Calcination Time ◽

Calorimetric Analysis ◽

X Ray ◽

Before And After ◽

Mechanical Performances

This work aims to study the feasibility of making a geopolymer cement based on dredged sediments, from the Fergoug dam (Algeria) and to evaluate their construction potential particularly interesting in the field of special cementitious materials. These sediments due to their mineralogical composition as aluminosilicates; are materials that can be used after heat treatment. Sedimentary clays were characterized before and after calcination by X-ray diffraction, ATG / ATD, spectroscopy (FTIR) and XRF analysis. The calcination was carried out on the raw material sieved at 80 μm for a temperature of 750 ° C, for 3.4 and 5 hours. The reactivity of the calcined products was measured using isothermal calorimetric analysis (DSC) on pastes prepared by mixing an alkaline solution of sodium hydroxide (NaOH) 8 M in an amount allowing to have a Na / Al ratio close to 1 (1: 1). Also, cubic mortar samples were prepared with a ratio L / S: 0.8, sealed and cured for 24 hours at 60 ° C and then at room temperature until the day they were submited to mechanical testing. to check the extent of geopolymerization. The results obtained allowed to optimize the calcination time of 5 hours for a better reactivity of these sediments, and a concentration of 8M of sodium hydroxide and more suitable to have the best mechanical performances.

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Calorimetric analysis of the polymerization reaction of a phenolic resin

Thermochimica Acta ◽

10.1016/0040-6031(95)02356-9 ◽

1995 ◽

Vol 269-270 ◽

pp. 201-211 ◽

Cited By ~ 30

Author(s):

J.M. Kenny ◽

G. Pisaniello ◽

F. Farina ◽

S. Puzziello

Keyword(s):

Phenolic Resin ◽

Polymerization Reaction ◽

Calorimetric Analysis

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Real-Time Temperature Estimation in a Multiple Device Power Electronics System Subject to Dynamic Cooling

IEEE Transactions on Power Electronics ◽

10.1109/tpel.2015.2443034 ◽

2016 ◽

Vol 31 (4) ◽

pp. 2709-2719 ◽

Cited By ~ 10

Author(s):

Jonathan N. Davidson ◽

David A. Stone ◽

Martin P. Foster ◽

Daniel T. Gladwin

Keyword(s):

Power Electronics ◽

Real Time ◽

Temperature Estimation ◽

Dynamic Cooling

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