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- 摘要
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- 实验方案
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Suppression of crystallization in ZBLAN glass by rapid heating and cooling processing
摘要： ZBLAN glass is a heavy metal fluoride glass that tends to undergo heavy devitrification, resulting in a crystalline material. It has many applications, including its use as an optical waveguide for fibre optic technology. However, when the glass is processed with traditional casting techniques, crystallites form readily that act as scattering centres, which results in large attenuation losses. In this study, it has been experimentally demonstrated that processing ZBLAN rapidly with a heating rate of 25,000 K/min and cooling rate of 4,000 K/min yields test samples that are fully amorphous and retain a disordered molecular arrangement characteristic of its molten state. This novel method was developed using a specifically designed equipment named a Rapid Electro-thermal Processing Device, or “REPD”. The REPD applies ohmic heating and thermal conduction to a heat sink to rapidly process the ZBLAN material. The absence of crystallites in the rapidly processed ZBLAN test samples were verified using transmission electron microscopy (TEM) analysis. Applying a theoretical algorithm, the critical cooling rate for yielding fully amorphous ZBLAN glass was determined to be 1081 K/min for a sample volume of 9.4 x 10-8 m3.
关键词： rapid cooling,microscopy,crystallization,ohmic heating,cooling rate,Joule heating,rapid heating,diffraction experiment,ZBLAN
更新于2025-09-23 15:23:52
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Energy and exergy performance assessment of a novel solar-based integrated system with hydrogen production
摘要： In this study, a new solar power assisted multigeneration system designed and thermodynamically analyzed. In this system, it is designed to perform heating, cooling, drying, hydrogen and power generation with a single energy input. The proposed study consists of seven sub-parts which are namely parabolic dish solar collector, Rankine cycle, organic Rankine cycle, PEM-electrolyzer, double effect absorption cooling, dryer and heat pump. The effects of varying reference temperature, solar irradiation, input and output pressure of high-pressure turbine and pinch point temperature heat recovery steam generator are investigated on the energetic and exergetic performance of integration system. Thermodynamic analysis result outputs show that the energy and exergy performance of overall study are computed as 48.19% and 43.57%, respectively. Moreover, the highest rate of irreversibility has the parabolic dish collector with 24,750 kW, while the lowest rate of irreversibility is calculated as 5745 kW in dryer. In addition, the main contribution of this study is that the solar-assisted multi-generation systems have good potential in terms of energy and exergy efficiency.
关键词： Exergy,Energy,Solar energy,Heating-cooling,Hydrogen,Multigeneration
更新于2025-09-09 09:28:46