Author: admin
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Dehumidification
Abstract Humidification/dehumidification (H/D) is in fact a small to medium capacity desalination method driven by solar energy or waste heat. In this chapter, initially a short historical introduction is given on how this method is derived from solar distillation procedure by using separate devices (champers or towers) for evaporation and condensation processes in contrary to solar distillation where the two operations…
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Maintenance of humidity
Energy impacts Adiabatic humidification can offer an advantage if humidification is required at the same time that cooling is needed. Some type of cooling is needed most of the year for many air-handling systems. This type of humidification will provide a free cooling effect along with the humidifying. However, during the heating season adiabatic humidification can result…
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HUMIDIFIERS
The simplest method of humidifying the inspired gases is the instillation of water droplets directly into the trachea, but this is the least satisfactory technique and cannot be recommended for routine use. It carries the danger that, if the drip is run too rapidly, the water or saline instilled into the trachea may lead to a…
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Web version of Monte Carlo simulation
This page provides a limited web-based version of the Monte Carlo simulation in case you are not able to run it in IGOR Pro. There are a limited number of choices of interaction parameter, temperature and composition. Video clips generated by running the simulation in IGOR Pro show the progression from an initially disordered state…
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Monte Carlo simulation
Computer modelling is a useful tool in representing and predicting atomic processes. A simulation has been created using IGOR Pro, a powerful graphing, data analysis, and programming tool for scientists and engineers produced by WaveMetrics. IGOR Pro is available for both Windows and Macintosh and a demo version can be downloaded from the WaveMetrics website. If…
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Precipitates from solid solution
The precipitation of a solid phase from a liquid matrix is governed by a balance between the thermodynamic driving force and the energy penalty for creating new solid-liquid surface interfaces. This determines the size and shape of the precipitates. The precipitation of a solid phase from a solid parent phase is very similar. There are…
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Demonstration
A mixture of equal quantities of cyclohexane and aniline contained in a sealed vial is heated to approximately 35 ºC (i.e. just above the critical temperature), using a water bath (or water from a hot tap). The mixture is allowed to cool, and a laser is pointed at the vial so that it shines onto…
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Demonstration of phase separation
The transition from a single phase to two phases (and vice-versa) can be easily demonstrated using a mixture of two suitable liquids. A mixture of cyclohexane and aniline can exist as two separate phases or as a single phase, depending on the temperature. The thermodynamic transition between these two states can be understood by considering…
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Exsolution in phase diagrams
A binary solid solution can show a phase diagram as follows: The solidus and liquidus separate the single phase regions. This is similar to the Cu-Ni phase diagram. If the system demonstrates exsolution, then there will be a region in the solid state where two solid phases form from the solid solution. This is common and…
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Free energy
The free energy of mixing is defined as: ΔGmix = ΔHmix – TΔSmix The variation in free energy as a function of composition and temperature can be considered for three different situations: an ideal solution, a non-ideal solution with a positive enthalpy of mixing, and a non-ideal solution with a negative enthalpy of mixing. 1. Ideal solid solution, ΔHmix = 0…