Mário Neves

Marine spatial planning and oil spill risk analysis: finding common grounds.

A flow of key information links marine spatial planning (MSP) and oil spill risk analysis (OSRA), two distinct processes needed to achieve true sustainable management of coastal and marine areas. OSRA informs MSP on areas of high risk to oil spills allowing a redefinition of planning objectives and the relocation of activities to increase the ecosystems overall utility and resilience. Concomitantly, MSP continuously generates a large amount of data that is vital to OSRA. The Environmental Sensitivity Index (ESI) mapping system emerges as an operational tool to implement the MSP-OSRA link. Given the high level of commonalities between ESI and MSP data (both in biophysical and human dimensions), ESI tools (both paper maps and dynamic GIS-based product) are easily developed to further inform MSP and oil spill risk management. Finally, several other benefits from implementing the MSP-OSRA link are highlighted.

The value of a pumping-hydro generator in a system with increasing integration of wind power

Portugal established a strong commitment to increase the installed renewable capacity in order to decrease its external energy dependency. These goals are being achieved mainly due to increasing levels of wind power. One of the main characteristics of wind power is the inherent unpredictability and variability. By allowing the energy storage, pumped-hydro units are able to cope with this drawback, promoting the match between generation and consumption. This paper presents a model based on market prices to determine the optimal bidding strategies that enable the total profit maximization of a pumped-hydro unit. It is considered that this unit participates in the Iberian day-ahead electricity market and in the portuguese ancillary services market. The optimal bids of the unit were calculated for scenarios with different levels of wind energy in the day-ahead market. The results showed that most of the income of the pumped-hydro unit was obtained from the spinning reserve market.

Design of a linear synchronous motor with high temperature superconductor materials in the armature and in the field excitation system

The high diamagnetism observed in high temperature superconducting (HTS) materials lead to applications involving levitation such as the linear synchronous motor (LSM). Certain features taken into account in conventional LSM design cannot be applied in the HTS case, due to these materials characteristics, such as BSCCO stiffness, when used as armature windings. Also other design features, e.g. slot skewing, which reduces the space harmonics of the air gap magnetic flux density, thus influencing motor performance, plays an important role in final cost. These and other aspects such as the thrust force or the effect of motor control through an inverter are examined in this paper, where the analytical and numerical methodologies involved in the design optimisation of a LSM demonstrator with premagnetised YBCO pellets in the field excitation system and BSCCO armature windings are described. Simulation results are also included.

Chapter 6 The rock coast of continental Europe in the Atlantic

Abstract Rocky coasts occur along more than one-third (37%) of the Atlantic continental European coastline, approximately 3666 km, often forming vertical cliffs and characteristically gently sloping shore platforms. The continental European Atlantic rocky coasts show a great variability of rock types and structural contexts, as well as different wave climates and tidal ranges. Through a review of previously published data on cliff retreat rates and shore platform erosion measured on monthly, seasonal, annual and decadal timescales, this paper highlights the different processes and agents, their magnitude and frequency in shaping rocky coasts. In particular, the links between cliff retreat, shore platform evolution, present dynamics and inheritance (understood as whether platform and other rock coast features were shaped by a higher sea level than the present) comprise one of the major contributions from continental European Atlantic rocky coasts to a global understanding of rock coast coastal geomorphology.

Identification of hazardous zones combining cliff retreat rates with landslide susceptibility assessment

ABSTRACT Epifânio, B., Zêzere, J.L., Neves, M., 2013. Identification of hazardous zones combining cliff retreat with landslide susceptibility assessment. Landslides are one of the main natural hazards which affect the coastal cliffs of Lourinhã council, located in Central Portugal. In this work, a methodology for hazard evaluation on coastal cliffs is presented, which combines the calculation of cliff retreat rates with landslide susceptibility assessment essential because landslide usually do not affect the cliff top. A landslide inventory was produced by aerial photo interpretation and a systematic field survey. The entire coastal stretch was split into 50m-long areas, resulting in 261 terrain mapping units. For each unit, 9 landslide predisposing factors were derived and classified. A predictive susceptibility model was developed using the Information Value method and the respective degree of fit was assessed using standard Receiver Operator Curves (ROC). Cliff retreat rates were calculated for a 60-year period using the ESRI′s Digital Shoreline Analysis System ArcGIS extension on a set of aerial photographs (which were manually geo-referenced and ortho-rectified) and a digital orthophotomap. Subsequently, predicted susceptibility data were integrated with the computed cliff retreat rates in a hazard matrix in order to create a map of the coastal cliff hazard. Cliff retreat rates ranged from 0.013 to 0.130m/yr and landslide susceptibility ranged from very high (4.2% of terrain unit) to low (0.8 % of terrain units). Approximately half of the study rocky coast is identified as being in a high hazard class. Thus, it is essential that hazard zones are considered for land use planning and management in order to reduce the probability of future incidents related to slope instability.

Economic limitations of the HVAC transmission system when applied to offshore wind farms

With the onshore wind power potential, practically at the limit in Portugal, it is necessary to explore the offshore potential. The continental plate is very “aggressive”, from a few hundred meters of seashore, the bathymetric, falls hundreds of meters. To overcome this situation and profit the offshore potential, it is necessary to place the wind farms, in deep waters, increasing the maximum of power of the wind power turbines. The traditional HVAC (High Voltage Alternating Current) transmission, in certain circumstances may be limitative when using in submarine cables. The mechanisms of the supply systems in HVAC, in its traditional way (air-lines), are faced with constraints. This kind of subsea infrastructure imposes restrictions, just by the fact that the capacity and inductance parameters are significant, which, when dealing with energy transmission, make “impossible” the power transmission due to its high consumption of reactive power. Also the economic aspects becomes extremely relevant. With the technological evolution of the wind platforms turbines, Portugal intent to increase the power of the offshore wind farms. I this paper with was analyzed, the supply systems in HVAC, when applied to offshore wind farms present limitations. The solution can be the HVDC (High Voltage Direct Current) technology as it reveals to be the most adequate to the energy transmission associated with this offshore wind farms, in certain circumstances. In addition to the technical factors, it was also analyzed the costs associated with this to types supply systems. And some conclusions are presented in order to define a limit between this to systems.

Numerical Design Methodology for an All Superconducting Linear Synchronous Motor

One potential advantage of the application of superconducting materials in electrical machines is the possibility to build lighter and compact devices by removing iron. These machines find applications, e.g., in systems where cryogenics is already available, or in naturally cryogenic environments. The design of motors with high temperature superconductors (HTS) presents issues unconsidered in classical machines, besides considerations on cryogenics, such as HTS brittleness or mechanical restrictions. Moreover, HTS’ electromagnetic properties also degrade due to flux density components, which arise if there is no iron to guide magnetic flux. Several aspects must thus be considered in the design stage, as applications may turn less attractive or even unfeasible. In this paper these issues are detailed, and a numerical methodology for the design of an all superconducting (without iron or conventional conductors) linear synchronous motor is presented.

Disc Motor: Conventional and Superconductor Simulated Results Analysis

Taking into consideration the development and integration of electrical machines with lower dimensions and higher performance, this paper presents the design and development of a three-phase axial flux disc motor, with 50 Hz frequency supply. It is made with two conventional semi-stators and a rotor, which can be implemented with a conventional aluminum disc or a high temperature-superconducting disc. The analysis of the motor characteristics is done with a 2D commercial finite elements package, being the modeling performed as a linear motor. The obtained results allow concluding that the superconductor motor provides a higher force than the conventional one. The conventional disc motor presents an asynchronous behavior, like a conventional induction motor, while the superconductor motor presents both synchronous and asynchronous behaviors.

Geomorphology of the Arrábida Chain (Portugal)

Geomorphological maps are crucially important in geomorphology studies, allowing the representation of topographic and geological data in an interpretative, dynamic and appealing way. In this paper, a medium-scale (1:70,000) geomorphological map is presented with the objective of facilitating the analysis and interpretation of the Plio-Quaternary landscapes of the Arrábida Chain, central-west Portugal. The map results from the combination of field and laboratory techniques, including aerial-photo interpretation, digital terrain data analysis and the morphometric study of landforms.

A new open-loop control method for stepping motor driving

Stepping motors are electromagnetic incremental-motion actuators, which, when energized by a voltage and current input, index in given angular increments. Their inherent positional accuracy makes them suitable for a wide range of motion control and industrial positioning applications, especially when slow and precise movement is required. However, their speed is limited by their torque which diminishes when the applied pulse train becomes too fast. To be more adequate to the necessities of higher speed applications their behavior can be improved through better electrical controller and motor designs.