Solid–liquid and liquid–solid transitions in metal nanoparticles

2017 ◽  
Vol 19 (8) ◽  
pp. 5994-6005 ◽  
Author(s):  
M. Hou
Keyword(s):  
Activation Energy ◽  
Metal Nanoparticles ◽  
Latent Heat ◽  
Latent Heat Of Melting ◽  
Solid Liquid

At the nanoscale, the activation energy of solidification is found equal to the latent heat of melting.

Scale effects in the latent heat of melting in nanopores

2013 ◽  
Vol 139 (4) ◽  
pp. 044701 ◽  
Author(s):  
J.-H. Shin ◽  
J.-Y. Parlange ◽  
M. R. Deinert
Keyword(s):  
Latent Heat ◽  
Scale Effects ◽  
Latent Heat Of Melting

Solid–Liquid Diffusion and Phase Growth Kinetics in Mg-Ca Binary System

2015 ◽  
Vol 816 ◽  
pp. 418-423
Author(s):  
Xin Li ◽  
Bin Jiang ◽  
Hong Yang ◽  
Xiang Sheng Xia ◽  
Jia Hong Dai ◽  
...  
Keyword(s):  
Activation Energy ◽  
Diffusion Layer ◽  
Diffusion Mechanism ◽  
Dendritic Structure ◽  
Diffusion Time ◽  
Diffusion Couples ◽  
Phase Growth ◽  
Liquid Diffusion ◽  
Solid Liquid ◽  
Exponential Relation

The solid–liquid diffusion between Mg and Mg-10 at.% Ca alloy was studied at a temperature range of 570°C to 630°C for 10, 20, 30min, respectively. Only one compound, Mg2Ca, was observed in the diffusion couples. As the diffusion time increased, the dendritic structure of the diffusion layer became coarser. The thickness of the diffusion layer had an exponential relation to the experimental temperature. The Mg2Ca phase was observed to follow parabolic growth with diffusion time, which suggested that the growth of the Mg2Ca phase was controlled by diffusion mechanism. The activation energy was determined to be 111.28 kJ/mol.

scholarly journals Analysis of Heat Transfer and Natural Convective of a Phase Change Material

2021 ◽  
Vol 9 (VII) ◽  
pp. 3028-3037
Author(s):  
T. Ravi Kumar
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Heat Storage ◽  
Storage Device ◽  
Latent Heat Storage ◽  
Recovery System ◽  
Solid Liquid ◽  
Change Material

A phase-change material (PCM) is a substance with a high latent heat storage capacity which on melting and solidifying at a certain temperature, is capable of storing and releasing large amounts of energy. Various PCM like Paraffin wax, stearic acid are considered which are used to absorb heat from the coolant water from the engine. The conduction and convection criterion of heat transfer enable the PCM to store this heat as latent heat. The amount of convection and temperature change brought about due to the heat flux has been simulated and studied in detail using FLUENT. The thermal energy storage device (TESD) works on the effect of absorption and rejection of heat during the solid-liquid phase change of heat storage material. The overall function of the TESS is dominated by the PCM. The PCM material should be selected considering the application and the working conditions. Depending on the applications, the PCMs should first be selected based on their melting temperature for heat recovery system.

scholarly journals The Thermal Activation of Nsu Clay for Enhanced Alumina Leaching Response

2019 ◽  
Vol 16 ◽  
pp. 34-46
Author(s):  
Udochukwu Mark ◽  
Charles Nwachukwu Anyakwo ◽  
Okechukwu Onyemaobi ◽  
Chijioke Samson Nwobodo
Keyword(s):  
Activation Energy ◽  
Thermal Activation ◽  
Leach Solution ◽  
Kaolinite Clay ◽  
Alumina Production ◽  
Calcination Temperatures ◽  
Activation Conditions ◽  
Solid Liquid ◽  
Heating Up ◽  
Better Than

The thermal activation conditions for enhancing the leaching of alumina from Nsu clay from south-eastern Nigeria was investigated. The clay assayed 28.9% and 50.59% , comprising mainly kaolinite mineral (82.6%) and quartz (12.5%). Thermal activation rendered the alumina in the clay acid-soluble by transforming the clay from its crystalline nature to an amorphous phase or metakaolinite. The clay samples were heated at calcination temperatures of 500, 600, 700, 800, and 900 °C at holding times of 30, 60, and 90 minutes. Uncalcined clay samples and samples calcined at 1000 °C (holding for 60 minutes) were used in the control experiments. Leaching of alumina from the resulting clay calcines passing 300 μm sieve (-50 mesh) was done in 1M hydrochloric acid solution at room temperature using a solid/liquid ratio of 0.02g/ml and shaking speed of 100 rpm. The solubility data given by the fraction of Al ion taken into leach solution showed that the clay calcined at 700 °C (holding for 60 minutes) responded most to leaching. In general, it was observed that samples calcined for 60 minutes responded better than those held for 30 or 90 minutes. The activation energies for leaching the clay calcines were 29.50, 32.92, 26.71, 30.18, 29.18, and 33.24 kJ/mol for samples calcined for 60 minutes at 500, 600, 700, 800, 900, and 1000 °C, respectively. The activation energy of leaching for the uncalcined sample was 35.07 kJ/mol. Thus, calcines produced at 700 °C (holding for 60 minutes) had the highest leaching response for alumina and the lowest leaching activation energy of 26.71 kJ/mol. It is concluded therefore that Nsu kaolinite clay should be best calcined for alumina yield by heating up to 700 °C and holding for 60 minutes at that temperature. The clay deposit can be used as alternative resource for alumina production.

scholarly journals Enzyme-catalyzed Synthesis of Novel Solid–liquid Phase Change Energy Storage Materials Based on Levulinic Acid and 1,4 butanediol

2021 ◽  
Author(s):  
Siyu Zhai ◽  
Lihe Zhang ◽  
Xi Zhao ◽  
Qian Wang ◽  
Yin Yan ◽  
...  
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Latent Heat ◽  
Levulinic Acid ◽  
Rapid Development ◽  
Synthesis Process ◽  
Energy Storage Materials ◽  
Temperature Phase ◽  
Storage Materials ◽  
Latent Heat Of Melting

Abstract With the rapid development of society, all kinds of non-renewable energy resources are constantly developed and utilized, energy storage is one of the best ways to solve the energy shortage. In this study , levulinic acid (LA) and 1,4 butanediol (BDO) were used to synthesize a novel polyol ester (LABDO) by biological and chemical methods. The biological method exhibited excellent performance in the synthesis process, where 87.5% of LABDO yield under optimal conditions, while the chemical method had more byproducts and higher energy consumption. Finally, the thermal properties of the obtained phase change materials (PCMs) were evaluated. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed that the melting temperature of LABDO was 50.51°C, the latent heat of melting was 156.1J/g, and the pyrolysis temperature was 150-160°C. Compared with traditional paraffin wax, the prepared PCMs have suitable phase transition temperature, higher latent heat of melting and better thermal stability. The thermal conductivity can be increased to 0.34W·m-1· k-1 by adding expanded graphite. In summary, LABDO can be used as low temperature phase change energy storage materials.

scholarly journals Thermal characterization of the In–Sn–Zn eutectic alloy

10.30544/456 ◽  
2020 ◽  
Vol 25 (04) ◽  
pp. 325-334
Author(s):  
Dragan Manasijević ◽  
Ljubiša Balanović ◽  
Vladan Ćosović ◽  
Duško Minić ◽  
Milena Premović ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Melting Temperature ◽  
Latent Heat ◽  
Eutectic Alloy ◽  
Metallic Phase ◽  
Flash Method ◽  
Nominal Composition ◽  
Scanning Calorimetry ◽  
Latent Heat Of Melting

Thermal properties, including melting temperature, latent heat of melting, specific heat capacity and thermal conductivity, of a low-melting In–Sn–Zn eutectic alloy were investigated in this work. The In–Sn–Zn eutectic alloy with nominal composition 52.7In-44.9Sn-2.4Zn (at.%) was prepared by the melting of pure metals under an argon atmosphere. The conducted assessment consisted of both theoretical and experimental approaches. Differential scanning calorimetry (DSC) was used for the measurement of melting temperature and latent heat, and the obtained results were compared with the results of thermodynamic calculations. The measured melting temperature and the latent heat of melting for the In–Sn–Zn eutectic alloy are 106.5±0.1 °C and 28.3±0.1 Jg-1, respectively. Thermal diffusivity and thermal conductivity of the In–Sn–Zn eutectic alloy were studied by the xenon-flash method. The determined thermal conductivity of the investigated eutectic alloy at 25 °C is 42.2±3.4 Wm-1K-1. Apart from providing insight into the possibility for application of the investigated alloy as the metallic phase-change material, the obtained values of thermal properties can also be utilized as input parameters for various simulation processes such as casting and soldering.

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