17,352 research outputs found
Single cell performance studies on the Fe/Cr Redox Energy Storage System using mixed reactant solutions at elevated temperature
Experimental studies in a 14.5 sq cm single cell system using mixed reactant solutions at 65 C are described. Systems were tested under isothermal conditions i.e., reactants and the cell were at the same temperature. Charging and discharging performance were evaluted by measuring watt-hour and coulombic efficiencies, voltage-current relationships, hydrogen evolution and membrane resistivity. Watt-hour efficiencies ranged from 86% at 43 ma/sq cm to 75% at 129 ma/sq cm with corresponding coulombic efficiencies of 92% and 97%, respectively. Hydrogen evolution was less than 1% of the charge coulombic capacity during charge-discharge cycling. Bismuth and bismuth-lead catalyzed chromium electrodes maintained reversible performance and low hydrogen evolution under normal and adverse cycling conditions. Reblending of the anode and cathode solutions was successfully demonstrated to compensate for osmotic volume changes. Improved performance was obtained with mixed reactant systems in comparison to the unmixed reactant systems
Coherent population trapping and dynamical instability in the nonlinearly coupled atom-molecule system
We study the possibility of creating a coherent population trapping (CPT)
state, involving free atomic and ground molecular condensates, during the
process of associating atomic condensate into molecular condensate. We
generalize the Bogoliubov approach to this multi-component system and study the
collective excitations of the CPT state in the homogeneous limit. We develop a
set of analytical criteria based on the relationship among collisions involving
atoms and ground molecules, which are found to strongly affect the stability
properties of the CPT state, and use it to find the stability diagram and to
systematically classify various instabilities in the long-wavelength limit.Comment: 11 pages, 8 figure
Particulate matter air pollution exposure: role in the development and exacerbation of chronic obstructive pulmonary disease
Due to the rapid urbanization of the world population, a better understanding of the detrimental effects of exposure to urban air pollution on chronic lung disease is necessary. Strong epidemiological evidence suggests that exposure to particulate matter (PM) air pollution causes exacerbations of pre-existing lung conditions, such as, chronic obstructive pulmonary disease (COPD) resulting in increased morbidity and mortality. However, little is known whether a chronic, low-grade exposure to ambient PM can cause the development and progression of COPD. The deposition of PM in the respiratory tract depends predominantly on the size of the particles, with larger particles deposited in the upper and larger airways and smaller particles penetrating deep into the alveolar spaces. Ineffective clearance of this PM from the airways could cause particle retention in lung tissues, resulting in a chronic, low-grade inflammatory response that may be pathogenetically important in both the exacerbation, as well as, the progression of lung disease. This review focuses on the adverse effects of exposure to ambient PM air pollution on the exacerbation, progression, and development of COPD
Effective DBHF Method for Asymmetric Nuclear Matter and Finite Nuclei
A new decomposition of the Dirac structure of nucleon self-energies in the
Dirac Brueckner-Hartree-Fock (DBHF) approach is adopted to investigate the
equation of state for asymmetric nuclear matter. The effective coupling
constants of , , and mesons with a density
dependence in the relativistic mean field approach are deduced by reproducing
the nucleon self-energy resulting from the DBHF at each density for symmetric
and asymmetric nuclear matter. With these couplings the properties of finite
nuclei are investigated. The agreement of charge radii and binding energies of
finite nuclei with the experimental data are improved simultaneously in
comparison with the projection method. It seems that the properties of finite
nuclei are sensitive to the scheme used for the DBHF self-energy extraction. We
may conclude that the properties of the asymmetric nuclear matter and finite
nuclei could be well described by the new decomposition approach of the G
matrix.Comment: 16 pages, 5 figure
Large N, chiral approach to M at finite temperature
We study the temperature dependence of the eta and eta[prime] meson masses within the framework of U(3)LΓU(3)R chiral perturbation theory, up to next-to-leading order in a simultaneous expansion in momenta, quark masses and number of colors. We find that both masses decrease at low temperatures, but only very slightly. We analyze higher order corrections and argue that large Nc suggests a discontinuous drop of Meta[prime] at the critical temperature of deconfinement Tc, consistent with a first order transition to a phase with approximate U(1)A symmetry
Quality and robustness improvement for real world industrial systems using a fuzzy particle swarm optimization
This paper presents a novel fuzzy particle swarm optimization with cross-mutated (FPSOCM) operation, where a fuzzy logic system developed based on the knowledge of swarm intelligence is proposed to determine the inertia weight for the swarm movement of particle swarm optimization (PSO) and the control parameter of a newly introduced cross-mutated operation. Hence, the inertia weight of the PSO can be adaptive with respect to the search progress. The new cross-mutated operation intends to drive the solution to escape from local optima. A suite of benchmark test functions are employed to evaluate the performance of the proposed FPSOCM. Experimental results show empirically that the FPSOCM performs better than the existing hybrid PSO methods in terms of solution quality, robustness, and convergence rate. The proposed FPSOCM is evaluated by improving the quality and robustness of two real world industrial systems namely economic load dispatch system and self-provisioning systems for communication network services. These two systems are employed to evaluate the effectiveness of the proposed FPSOCM as they are multi-optima and non-convex problems. The performance of FPSOCM is found to be significantly better than that of the existing hybrid PSO methods in a statistical sense. These results demonstrate that the proposed FPSOCM is a good candidate for solving product or service engineering problems which have multi-optima or non-convex natures
Potential of Augmented Reality for Intelligent Transportation Systems
Rapid advances in wireless communication technologies coupled with ongoing
massive development in vehicular networking standards and innovations in
computing, sensing, and analytics have paved the way for intelligent
transportation systems (ITS) to develop rapidly in the near future. ITS
provides a complete solution for the efficient and intelligent management of
real-time traffic, wherein sensory data is collected from within the vehicles
(i.e., via their onboard units) as well as data exchanged between the vehicles,
between the vehicles and their supporting roadside infrastructure/network,
among the vehicles and vulnerable pedestrians, subsequently paving the way for
the realization of the futuristic Internet of Vehicles. The traditional intent
of an ITS system is to detect, monitor, control, and subsequently reduce
traffic congestion based on a real-time analysis of the data pertinent to
certain patterns of the road traffic, including traffic density at a
geographical area of interest, precise velocity of vehicles, current and
predicted travelling trajectories and times, etc. However, merely relying on an
ITS framework is not an optimal solution. In case of dense traffic
environments, where communication broadcasts from hundreds of thousands of
vehicles could potentially choke the entire network (and so could lead to fatal
accidents in the case of autonomous vehicles that depend on reliable
communications for their operational safety), a fall back to the traditional
decentralized vehicular ad hoc network (VANET) approach becomes necessary. It
is therefore of critical importance to enhance the situational awareness of
vehicular drivers so as to enable them to make quick but well-founded manual
decisions in such safety-critical situations.Comment: In: Lee N. (eds) Encyclopedia of Computer Graphics and Games.
Springer, Cham, 201
Thermal performance of an active-passive ventilation wall with phase change material in solar greenhouses
Β© 2018 Elsevier Ltd Using phase change material (PCM) in the north wall of solar greenhouses has been recommended as an efficient solution for promoting their indoor thermal environment. In this type of walls, however, there is always a thermal-stable layer, which would greatly decrease their heat storage capacity. To solve this problem, an active-passive ventilation wall with PCM has been developed in this study, and a comparative study was carried out using both experimental and numerical methods to justify its advantages over conventional walls. Several important parameters have been monitored or calculated to reflect the contribution of the newly proposed method to the performance of the middle layer of the wall, the indoor thermal environment and the plantsβ growth. The obtained results confirmed the great effectiveness of the proposed wall in promoting the temperature of its middle layer and irradiated surface. In the newly proposed wall, there was no thermal-stable layer observed, resulting in a minimum temperature rise of 1.34 Β°C. The proposed solution also enhanced the wall's heat storage capacity by 35.27β47.89% and the heat release capacity by 49.93β60.21%, resulting in an average increase of indoor air temperature, daily effective accumulative temperature and soil temperature by 1.58β4.16 Β°C, 33.33β55.06% and 0.53β1.09 Β°C, respectively. The plant height, stem diameter and fruit yield have been increased by 30%, 25% and 28%, respectively
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