Conceptual
methods are illustrated for the development of operating
policies for batch reactive crystallization processes. Two processes,
production of barium sulfate and production of l-glutamic
acid, are studied. For barium sulfate, the critical seed loading ratio
is found to be above the practical limit, which suggests that seeding
cannot be employed to suppress nucleation. Conversely, for l-glutamic acid, the critical seed loading ratio is below the practical
limit for a wide range of seed sizes, suggesting that seeding can
be used to suppress nucleation almost entirely. These results are
verified by rigorous process simulation. Furthermore, for the barium
sulfate process, a plot of nucleation rate B versus
growth rate G is concave, indicating that an early
growth trajectory (with supersaturation highest at the beginning of
the batch) will minimize the nucleated mass, while for the l-glutamic acid process the plot is convex, indicating that a late
growth trajectory will minimize the nucleated mass. These results
are also supported by rigorous simulation and optimization.
Real-time monitoring of cardiac health is helpful for patients with cardiovascular disease. Many telemedicine systems based on ubiquitous computing and communication techniques have been proposed for monitoring the user's electrocardiogram (ECG) anywhere and anytime. Usually, wet electrodes are used in these telemedicine systems. However, wet electrodes require conduction gels and skin preparation that can be inconvenient and uncomfortable for users. In order to overcome this issue, a new non-contact electrode circuit was proposed and applied in developing a mobile electrocardiogram monitoring system. The proposed non-contact electrode can measure bio-potentials across thin clothing, allowing it to be embedded in a user's normal clothing to monitor ECG in daily life. We attempted to simplify the design of these non-contact electrodes to reduce power consumption while continuing to provide good signal quality. The electrical specifications and the performance of monitoring arrhythmia in clinical settings were also validated to investigate the reliability of the proposed design. Experimental results show that the proposed non-contact electrode provides good signal quality for measuring ECG across thin clothes.
Crystallization
is an ancient unit operation that remains vital
for the chemical process industry. Traditional single-effect evaporation
consumes a great deal of energy, and various alternatives to this
method have been proposed. In this work, the total cost of producing
a fixed quantity of different solid chemicals by crystallization from
water is determined for several different technologies: evaporative
crystallization, membrane distillation with porous hydrophobic membranes,
reverse osmosis membrane-assisted crystallization, and eutectic freeze
crystallization (EFC). Among the solute properties, the solubility
has the greatest effect on the cost of the process since it determines
the amount of water that must be removed per unit product produced.
If waste heat is available at a unit price lower than that of low-pressure
steam produced using coal or natural gas, then the assumed price of
waste heat also has a significant effect on the economics. The results
indicate that, if feasible, reverse osmosis has the lowest total annual
cost. On the other hand, for high osmotic pressure cases, EFC has
the lowest cost when cheap heating energy (waste heat) is not available.
On the contrary, a conventional single or multiple effect evaporative
crystallization has the lowest cost among the remaining options when
heating energy is cheap or solubility is high. Moreover, eutectic
temperature plays important role when determining the best technology
when solubility is between 0.2 and 0.6 kg/kg solution.
Due to the rapid development of computers, researchers have made efforts since the 1990s to develop typhoon forecasting models and stochastic typhoon simulation models to assess typhoon disasters and risks. Typhoon forecasting models are primarily used to predict and track the movement of typhoons and provide warning information to the general public before landfall. Stochastic typhoon simulation models can assess extreme wind speeds and compensate for the limitations of current observations and simulation data length. Taiwan experiences approximately three to four typhoons yearly, of varying intensities and paths. Whether the marine meteorological data includes events of strong typhoon centers passing through will affect the results of frequency analysis. The development of offshore wind power in Taiwan is closely related to the unique marine meteorological conditions throughout the lifecycle stages, including wind farm site selection, feasibility studies, planning and design, construction and installation, operation and maintenance, and decommissioning. This study references relevant research and analyzes sixty-three scenarios using nine types of maximum storm wind speed radii and seven Holland-B parameters. The data from Japan Meteorological Agency Best Track Data (JMA BTD) is utilized, explicitly selecting 20 typhoon events after 2000 for wind speed simulation using a typhoon wind speed model. After validating the typhoon wind speeds with observation data from the Central Weather Bureau (CWB) in Hsinchu and the Longdong buoy, the technique of Monte Carlo simulation is utilized to generate synthetic typhoons randomly. The average of the relative absolute errors for the simulated maximum wind speeds is calculated, and through comprehensive evaluation, optimal parameter combinations (Rm, B) are obtained.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.