Browsing by Issue Date, starting with "2018-09-12"
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- A review of fault tolerant design in wave energy convertersPublication . Kamarlouei, Mojtaba; Gaspar, José F.; Guedes, Carlos; Cruz, B. F.; Mendes, Mário J. G. C.The main objective of this pape is to presente a review on typical faults including the actual development and application of the fault tolerant design techniques in WEC systems and subsystems. Also, various WEC devices are studied and categorized in three diferente maintenance levels based on the defined criteria in maintenance standard. In this paper, the oscillating body and structure, power take-off system and transmission units, control,safety and survivability units are considered as the essencial componentes of the WEC for fault and failure study. Moreover, several faults are identified and fault tolerant design techniques are proposed for these systems. Moreover, several faults are identified and fault tolerant design techniques are proposed for these systems.
- Prototyping and wave tank testing of a floating platform with point absorbersPublication . Kamarlouei, Mojtaba; Gaspar, José F.; Calvário, M.; Hallak, Thiago S.; Soares, Carlos Guedes; Mendes, Mário J. G. C.; Thiebaut, FlorentThe main aim of this paper is to present the experimental results of a concept of a platform, with several point energy absorbers. A floating circular array of point absorbers, in 1-27 scale, was tested in the wave tank. The hydrodynamic behavior of the platform was studied in different configurations. Moreover, the performance of the platform was assessed in different sea states with and without point absorbers attached to the platform.
- Comparison of portable emissions measurement systems (PEMS) with laboratory grade equipmentPublication . Varella, Roberto Aliandro; Giechaskiel, Barouch; Sousa, Luís; Duarte, GonçaloReal-driving emissions (RDE) testing with portable emissions measurement systems (PEMS) during the type approval and in-service conformity of light-duty vehicles was recently introduced in the European Union legislation. In this paper, three PEMS were compared with laboratory analyzers connected to the tailpipe and the dilution tunnel. The tests were conducted with two Euro 6 vehicles (one gasoline and one diesel) performing the World harmonized Light vehicles Test Cycle (WLTC) and a pre-recorded RDE cycle on a chassis dynamometer. The results showed that the differences of the PEMS gas analyzers compared to the laboratory references were typically within 2% for CO2 and 5% for NOx. The CO2 and NOx mass emissions were within 10% and 15%, respectively, with only a few exceptions. The exhaust flow rate measurements were within 10% at low speeds (urban conditions), and 5% at higher speeds. These results confirm the legislated permitted tolerances and the 2017 PEMS uncertainty estimates.