Search results for "Mechanical engineering"
showing 10 items of 4245 documents
A novel renewable polygeneration system for a small Mediterranean volcanic island for the combined production of energy and water: Dynamic simulation…
2014
Abstract This paper investigates the integration of solar and geothermal energy in a novel polygeneration system producing simultaneously: electricity, thermal energy, cooling energy and fresh water. The polygeneration system under analysis includes concentrating photovoltaic/thermal solar collectors (CPVT), a Geothermal Well (GW) a multi-effect distillation (MED) system for seawater desalination, a single-stage LiBr–H2O absorption chiller and additional components, such as: storage tanks, heat exchangers and balance of plant devices. The CPVT produces simultaneously electrical energy and thermal energy, at a maximum temperature of about 100 °C. The electrical energy is delivered to the gri…
Performance evaluation of hybrid RO/MEE systems powered by a WTE plant
2008
Abstract The solid waste management is, in different contexts, a very critical issue. The use of landfills can no longer be considered a satisfactory environmental solution, therefore new methods have to be chosen and waste-to-energy (WTE) plants would provide an answer. Today's WTE plants are a far cry from their polluting predecessors. Using modern combustion and pollution control technology, WTE plants are able to retrieve considerable amounts of energy from waste combustion while minimizing emissions. As we know, is possible to recover thermal energy by combusting municipal solid waste (MSW) for electricity generation and district heating. However, with everincreasing population and rap…
Enhancing carbon dots fluorescence via plasmonic resonance energy transfer
2022
Using plasmonic interactions to engineer optical properties at the nanoscale is an important challenge of current photonics. Here we establish a general strategy to enhance the orange emission of carbon dots by coupling them to gold nanoparticles through a polymeric spacer in solution. We exploit the overlap between the surface plasmon resonance of gold and the electronic transitions of carbon dots to achieve a fivefold increase of their fluorescence in the orange region, which is usually very weak. We demonstrate that this enhancement stems from an ultrafast resonance energy transfer from the coherent plasmonic state of the gold nanoantenna to the coupled carbon dot. Our study advances the…
Active Disturbance Rejection Station-Keeping Control of Unstable Orbits around Collinear Libration Points
2014
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://10.1155/2014/410989 An active disturbance rejection station-keeping control scheme is derived and analyzed for station-keeping missions of spacecraft along a class of unstable periodic orbits near collinear libration points of the Sun-Earth system. It is an error driven, rather than model-based control law, essentially accounting for the independence of model accuracy and linearization. An extended state observer is designed to estimate the states in real time by setting an extended state, that is, the sum of unmodeled dynamic and external disturbance. This tota…
Identification of LTI Time-Delay Systems with Missing Output Data Using GEM Algorithm
2014
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2014/242145 This paper considers the parameter estimation for linear time-invariant (LTI) systems in an input-output setting with output error (OE) time-delay model structure. The problem of missing data is commonly experienced in industry due to irregular sampling, sensor failure, data deletion in data preprocessing, network transmission fault, and so forth; to deal with the identification of LTI systems with time-delay in incomplete-data problem, the generalized expectation-maximization (GEM) algorithm is adopted to estimate the model parame…
Wind Turbine Pitch Control and Load Mitigation Using an L1 Adaptive Approach
2014
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2014/719803 We present an application of L1 adaptive output feedback control design to wind turbine collective pitch control and load mitigation. Our main objective is the design of an L1 output feedback controller without wind speed estimation, ensuring that the generator speed tracks the reference trajectory with robustness to uncertain parameters and time-varying disturbances (mainly the uniform wind disturbance across the wind turbine rotor). The wind turbine model CART (controls advanced research turbine) developed by the national renewab…
Effects of Surfactants on the Performance of CeO2 Humidity Sensor
2014
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2014/723050 Nanosized CeO 2 powders were synthesized via hydrothermal method with different types of surfactants (polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB), and sodium dodecylbenzenesulfonate (SDBS)). X-ray diffraction, Raman spectroscopy, and transmission electron microscopy were utilized to characterize the phase structures and morphologies of the products. The sample with CTAB as surfactant (CeO 2 -C) has the largest specific surface area and the smallest particle size among these three samples. The humidity sensor fa…
Fault detection for network control systems with multiple communication delays and stochastic missing measurements
2014
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://10.1155/2014/690461 This paper is concerned with fault detection problem for a class of network control systems (NCSs) with multiple communication delays and stochastic missing measurements. The missing measurement phenomenon occurs in a random way and the occurrence probability for each measurement output is governed by an individual random variable. Besides, the multiple communication delay phenomenon reflects that networked control systems have different communication delays when the signals are transferred via different channels. We aim to design a fault det…
Robust Decentralized Adaptive Neural Control for a Class of Nonaffine Nonlinear Large-Scale Systems with Unknown Dead Zones
2014
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2014/841306 The problem of robust decentralized adaptive neural stabilization control is investigated for a class of nonaffine nonlinear interconnected large-scale systems with unknown dead zones. In the controller design procedure, radical basis function (RBF) neural networks are applied to approximate packaged unknown nonlinearities and then an adaptive neural decentralized controller is systematically derived without requiring any information on the boundedness of dead zone parameters (slopes and break points). It is proven that the develop…
Robust Production Planning in Fashion Apparel Industry under Demand Uncertainty via Conditional Value at Risk
2014
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2014/901861 This paper presents a mathematical model for robust production planning. The model helps fashion apparel suppliers in making decisions concerning allocation of production orders to different production plants characterized by different lead times and production costs, and in proper time scheduling and sequencing of these production orders. The model aims at optimizing these decisions concerning objectives of minimal production costs and minimal tardiness. It considers several factors such as the stochastic nature of customer demand…