Search results for "TLA"
showing 10 items of 1764 documents
Simulation approach for improving CNC milling machines accuracy for single axis motion
2010
CNC milling machines are widely used in manufacturing processes. In time, their accuracy is decreasing, which directly influences the accuracy of the manufactured parts. This research proposes a simulation-based method for improving the accuracy of the above mentioned machines, which is suitable to be applied at the shop floor level. A model of the feed drive, using a dc servomotor as actuator, is the core of the proposed approach. Matlab & Simulink based simulation diagrams were built in order to test the behavior of the system.
Integration of DC power source in micro-grid using VSI with PLL technique
2015
The looming energy crisis is becoming the greatest challenge to the world today. As a consequence of this there is an increasing attention for alternative renewable energy resources. In future, renewable energy sources will be integrated with energy storage and it will require a proper converter for integrating with the grid. In order to achieve this, various power electronics topologies have to be incorporated between the grid and the renewable source(s). This paper presents the simulation and experimental implementation of DC power source integration in micro-grid using single phase ‘Voltage Source Inverter’ (VSI) with ‘Phase Locked Loop’ (PLL) topology. Firstly the appropriateness of the…
Identification and robust control of DC/DC converter Hammerstein model
2008
Abstract—This paper deals with model-based robust control of dc/dc power electronic converters. The converter is described by means of a Hammerstein model consisting of the nonlinear static characteristics of the converter and a linear time-invariant (LTI) uncertainmodel whose parameters depend on the actual duty-cycle operating range. This suggests that the controller be designed using robust control techniques. In view of applying robust control, identification of the earlier LTI models is performed by means of simulation experiments, carried out on a converter switching model implemented onMATLAB/SIMULINK environment. Internal model control (IMC) structure is employed for the controller …
Analysis of driving cycles effects on power supply requirements of a fuel cell powered light-weight electric vehicle
2015
In this paper, fuel cell powered lightweight vehicles are addressed. A MATLAB/Simulink simulation model including motor, electrical drive, the fuel cell and power electronics systems is implemented. The model is well suited to perform the driving cycle test, which reproduces the speed pattern of an electric vehicle through urban, rural or motorway routes. This paper aims at investigating the most suited driving cycle to design high performances hybrid power supply for electric vehicles in terms of cruising range, cost and size of the power supply equipment. For this purpose, a legislative and a real-world driving cycles are selected. Effects of driving cycles on the power system requirement…
Impact of integrating photovoltaic based DG on distribution network harmonics
2017
The process of integrating various distributed generation (DG) technologies in power system networks is increasing rapidly in the recent years. One major concern about the integration of DGs is their impact on network harmonics. The aim of this paper is to investigate the effects caused by the integration of photovoltaic DG in distribution networks on system harmonics. The penetration level, number of DG units, and their location are used as parameters in order to verify the effects of DG on system harmonics. Moreover, a study of single and double tuned filters is conducted as harmonics mitigation techniques. Detailed simulations using Matlab/Simulink are inserted in order to explain and ve…
Monetary valuation of salicylic acid, methylparaben and THCOOH in a Mediterranean coastal wetland through the shadow prices methodology
2018
The presence of pharmaceutical and personal care products and drugs of abuse (PPCPs) in wastewater treatment plants (WWTPs) indicates discharge of the effluent may not be suitable for the ecological balance of water ecosystems, such as wetlands. These PPCPs degrade water quality, considered as an ecosystem service (ES), provoking serious environmental impacts. Assessing the monetary value of PPCPs can be used as a proxy for environmental status of the ES of water quality (ESWQ). Considering PPCPs as non-desirable outputs of WWTPs, the shadow prices methodology has been implemented using directional distance function to measure the environmental avoided cost of removing salicylic acid (SA), …
Plankton participation in the performance of three constructed wetlands within a Mediterranean natural park.
2019
Abstract The contribution of plankton in the performance of three constructed wetlands (CWs) within the Albufera de Valencia Natural Park has been analyzed, taxonomic group by group, over a two-year operation period in the different sectors of each CW: horizontal subsurface-flow –A–, free-water surface flow –B– and lagoons –C–. Tancat de la Pipa CW (TPCW) only contains B–C sectors, while the others have all three types. Treatment efficiency of each sector type on the taxonomic groups was evaluated by calculating frequency of phytoplankton reduction (or zooplankton production), mass removal (or production) efficiencies and rates, and accumulated removed phytoplankton mass (or produced zoopla…
Shadow prices of emerging pollutants in wastewater treatment plants: Quantification of environmental externalities.
2017
Conventional wastewater treatment plants (WWTPs) are designed to remove mainly the organic matter, nitrogen and phosphorus compounds and suspended solids from wastewater but are not capable of removing chemicals of human origin, such as pharmaceutical and personal care products (PPCPs). The presence of PPCPs in wastewater has environmental effects on the water bodies receiving the WWTP effluents and renders the effluent as unsuitable as a nonconventional water source. Considering PPCPs as non-desirable outputs, the shadow prices methodology has been implemented using the output distance function to measure the environmental benefits of removing five PPCPs (acetaminophen, ibuprofen, naproxen…
Evaluation of clogging in full-scale subsurface flow constructed wetlands
2016
Abstract Treatment processes that occur in constructed wetlands can result in gradual clogging of the porous medium. Clogging may result in hydraulic malfunction and/or reduced treatment performance. The aim of this study was to analyze the hydraulic aspects of horizontal subsurface flow (H-SSF) constructed wetlands (CWs), and, in particular, to investigate the clogging phenomena through in situ measurements of hydraulic conductivity of the gravel bed, quantification of accumulated clog matter and flow paths visualization by means of tracer tests. Removal efficiencies of chemical and physical contaminants were also assessed. Experiments were carried out in three full-scale H-SSF CWs in Sici…
Effect of Integrating Photovoltaic Systems on Electrical Network Losses Considering Load Variation
2018
Planning of Distributed Generation (DG) units in the power distribution networks is an important issue, one of the most important considerations that is directly affected by installing DG units is the power losses. Improper allocation of DG units to the grid can lead to a noticeable increase in the power losses. Moreover, the load variation is considered as critical matter when studying the optimal scenario that minimizes the power losses in the network. The aim of this paper is to investigate the effect of integrating photovoltaic (PV) units on the distribution network losses considering load variation. The optimal parameters of the DG units were calculated for the various load demands in …