The Effect of Chemistry and Cooling Rate on the Latent Heat Released during the Solidification of the 3XX Series of Aluminum Alloys

2007 ◽  
pp. 299-304 ◽  
Author(s):  
Mile B. Djurdjevic ◽  
Jerry Sokolowski ◽  
Witold T. Kierkus ◽  
Glenn E. Byczynski
Keyword(s):  
Aluminum Alloys ◽  
Cooling Rate ◽  
Latent Heat ◽  
Heat Released

The Effect of Chemistry and Cooling Rate on the Latent Heat Released during the Solidification of the 3XX Series of Aluminum Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 299-304 ◽  
Author(s):  
Mile B. Djurdjevic ◽  
Jerry Sokolowski ◽  
Witold T. Kierkus ◽  
Glenn E. Byczynski
Keyword(s):  
Aluminum Alloys ◽  
Latent Heat ◽  
Solidification Process ◽  
Hypoeutectic Alloy ◽  
The Novel ◽  
Cooling Rates ◽  
Novel Concept ◽  
The Given ◽  
Heat Released ◽  
Different Levels

The latent heat of solidification of any alloy depends on its chemistry that consequently affects the macro and microstructures for the given solidification conditions. In order to analyze the effects of chemistry on the release of latent heat during solidification of the industrial 3XX series of aluminum alloys, four different levels of silicon (5, 7, 9 and 11wt% Si) and three different levels of copper (1, 2 and 4 wt% of Cu) were taken into consideration. The solidification process was studied at cooling rates of 6 and 10°C/minute. The solidification path of these alloys was determined and the corresponding latent heat released during the solidification process was measured using a Differential Scanning Calorimeter (DSC). The tested hypoeutectic alloy chemical composition was expressed by the novel concept of silicon equivalency. The findings indicate that increases in the cooling rates shift the characteristic temperatures toward lower values without having a significant effect on the amount of released latent heat.

scholarly journals Calorimetric analysis of ice onset temperature during cryoablation: a model approach to identify early predictors of effective applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elena Campagnoli ◽  
Andrea Ballatore ◽  
Valter Giaretto ◽  
Matteo Anselmino
Keyword(s):  
Cooling Rate ◽  
Latent Heat ◽  
Bovine Liver ◽  
Onset Temperature ◽  
Ice Formation ◽  
Scanning Calorimetry ◽  
Calorimetric Analysis ◽  
Early Predictors ◽  
Latent Heat Capacity ◽  
Model Approach

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.

Microstructure and Properties of Rapidly Solidified Al-Zn-Mg-Cu Alloy

2020 ◽  
Vol 993 ◽  
pp. 203-207
Author(s):  
Wei Min Ren ◽  
Zi Yong Chen ◽  
Zhi Lei Xiang ◽  
Li Hua Chai
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Cooling Rate ◽  
Rapid Solidification ◽  
Second Phase ◽  
Alloy Strip ◽  
Roller Speed ◽  
Microstructure And Properties ◽  
Cu Alloy ◽  
Rapidly Solidified

Refining grain plays an important role in improving the mechanical properties of aluminum alloys. However, the conventional casting method with a slow cooling rate can be easy to cause coarseness of the microstructure and serious segregation. In this paper, the rapid solidification of Al-Zn-Mg-Cu alloy was prepared by the single-roller belt method. The alloy strip was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and hardness test to study the microstructure and properties of the rapidly solidified aluminum alloy. The results show that the roller speed was an important parameters affecting the formability of the alloy. When the roller speed was 15 m/s, the aluminum alloy produced a thin bandwidth of 5 mm and a thickness of 150 um. As the rotation speed of the roller increased, the cooling rate of the melt increased, and the microstructure of the rapidly solidified Al-Zn-Mg-Cu aluminum alloy strip improved in grains refinement. Compared with the conventionally cast Al-Zn-Mg-Cu aluminum alloys, the Al-Zn-Mg-Cu aluminum alloys prepared by rapid solidification showed much finer crystal grains, and enhanced solid solubility of alloying elements with less precipitation of second phase and high hardness.

Microstructural Evolution during Ingot Preheat in 7xxx Aluminium Alloys for Thick Semiproduct Applications

2006 ◽  
Vol 519-521 ◽  
pp. 549-554 ◽  
Author(s):  
Seong Taek Lim ◽  
Yong Yun Lee ◽  
Il Sang Eun
Keyword(s):  
Aluminum Alloys ◽  
Cooling Rate ◽  
Temperature Interval ◽  
Microstructural Evolution ◽  
Aluminium Alloys ◽  
S Phase ◽  
Constitutional Change ◽  
Preheat Temperature ◽  
Quaternary Phase ◽  
M Phase

Recent 7xxx aluminum alloys have been designed for the finite use of thick semiproduct with contolled amount of constituent phases which mostly evolve during ingot preheat. In this study, the effects of constitutional change and preheat conditions of 7175 and 7050 type alloys on the evolution of constituent phases [M-, T-, S-phase and dispersoid] are presented. The constiuents evolve depending on the constitutional effect, primarily the change of Zn:Mg ratio, preheat condition comprising temperature and cooling rate following preheat. T- and M-phase are reprecipitated during cooling after preheat, depending on the alloy constitutions. S-phase is evolved depending on the constitution and preheat temperature, rather than preheat cooling rate. Prominent precipitation temperature interval of constituents are discussed in view of quaternary phase evolutions. In addition, evolutions of dispersoids together with M-phase are discussed. Specific alloy designs and preheat conditions could provide controlled microstructures for the thick 7xxx semiproducts.

Effect of Latent Heat Released by Freezing Droplets during Frost Wave Propagation

Langmuir ◽  
2018 ◽  
Vol 34 (22) ◽  
pp. 6636-6644 ◽  
Author(s):  
Shreyas Chavan ◽  
Deokgeun Park ◽  
Nitish Singla ◽  
Peter Sokalski ◽  
Kalyan Boyina ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Latent Heat ◽  
Heat Released

scholarly journals Numerical Simulation of the Effect of Cloud Condensation Nuclei Concentration on the Microphysical Processes in Typhoon Usagi

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Xiying Ye ◽  
Qimin Cao ◽  
Baolin Jiang ◽  
Wenshi Lin
Keyword(s):  
Latent Heat ◽  
Cloud Condensation Nuclei ◽  
Cloud Water ◽  
Weather Research And Forecasting ◽  
Forecasting Model ◽  
Condensation Nuclei ◽  
Microphysics Scheme ◽  
Sensitivity Tests ◽  
Microphysical Processes ◽  
Heat Released

The Weather Research and Forecasting model version 3.2.1 with the Lin microphysics scheme was used herein to simulate super typhoon Usagi, which occurred in 2013. To investigate the effect of the concentration of cloud condensation nuclei (CCN) on the development of typhoon Usagi, a control simulation was performed with a CCN concentration of 100 cm−3, together with two sensitivity tests: C10 and C1000, having CCN concentrations of 10 cm−3 and 1000 cm−3, respectively. The path, intensity, precipitation, microphysical processes, and the release of latent heat resulting from the typhoon in all three simulations were analyzed to show that an increase in CCN concentration leads to decreases in intensity and precipitation, an increase of the cloudless area in the eye of the typhoon, a more disordered cloud system, and less latent heat released through microphysical processes, especially the automatic conversion of cloud water into rainwater. Overall, an increase in CCN concentration reduces the total latent heat released during the typhoon suggesting that typhoon modification by aerosol injection may be optimized using numerical simulations to ensure the strongest release of latent heat within the typhoon.

Effect of Cell Density on Post-Thaw Viability in Cryopreserved Artificial Tissue

2000 ◽  
Author(s):  
Masanobu Ujihira ◽  
Yumi Matsumura ◽  
Chinatsu Kuroda ◽  
Koji Okaniwa ◽  
Kiyoshi Mabuchi
Keyword(s):  
Cooling Rate ◽  
Cell Density ◽  
Latent Heat ◽  
Human Fibroblasts ◽  
Test Chamber ◽  
Freezing Process ◽  
Cell Contact ◽  
Slow Cooling ◽  
Trypan Blue Exclusion ◽  
Artificial Tissue

Abstract The effect of cell density on the post-thaw viability of cells in cryopreserved artificial tissue was studied. Human fibroblasts were three-dimensionally cultured for 2 days in a collagen sponge (ϕ20×1mm) as an extracellular matrix to imitate biological tissue (artificial tissue). Different cell densities for the artificial tissue were used, from 104 to 107 cells/cm3. Four artificial tissues were first stacked in a test chamber, then frozen at a slow or fast cooling rate (either 1 or 50°C/min) in a solution of Dulbecco’s Modified Eagle Medium, 20% Fetal Bovine Serum, and 10% dimethylsulfoxide, then kept frozen at −196°C for 2 hours, and finally thawed. The collagen matrix of the artificial tissue was dissolved using collagenase. Post-thaw viability of fibroblasts was evaluated by using a trypan blue exclusion assay. The experiments were prepared, and then the latent heat of artificial tissue (3.5×3.5×1mm) during the freezing process was measured by using a differential scanning calorimeter. Results show that with increasing cell density, the post-thaw viability decreased, whereas the latent heat was almost independent of cell density. With increasing cell density at the slow cooling rate, the degree of supercooling of the intracellular solution increased with decreasing temperature, possibly leading to intracellular freezing. Moreover, when the cell density was high, cell-to-cell contact or an obstruction to dehydration seemed to induce intracellular freezing. Therefore, the post-thaw viability seems to decrease as the number of cells exhibiting intracellular freezing increased.

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