Wave boundary layer model in SWAN revisited

In this study, we extend the work presented in Du et al. (2017) to make the wave boundary layer model (WBLM) applicable for real cases by improving the wind-input and white-capping dissipation source functions. Improvement via the new source terms includes three aspects. First, the WBLM wind-input source function is developed by considering the impact of wave-induced wind profile variation on the estimation of wave growth rate. Second, the white-capping dissipation source function is revised to be not explicitly dependent on wind speed for real wave simulations. Third, several improvements are made to the numerical WBLM algorithm, which increase the model's numerical stability and computational efficiency. The improved WBLM wind-input and white-capping dissipation source functions are calibrated through idealized fetch-limited and depth-limited studies, and validated in real wave simulations during two North Sea storms. The new WBLM source terms show better performance in the simulation of significant wave height and mean wave period than the original source terms.</p

High-resolution large-scale onshore wind energy assessments: A review of potential definitions, methodologies and future research needs

The rapid uptake of renewable energy technologies in recent decades has increased the demand of energy researchers, policymakers and energy planners for reliable data on the spatial distribution of their costs and potentials. For onshore wind energy this has resulted in an active research field devoted to analysing these resources for regions, countries or globally. A particular thread of this research attempts to go beyond purely technical or spatial restrictions and determine the realistic, feasible or actual potential for wind energy. Motivated by these developments, this paper reviews methods and assumptions for analysing geographical, technical, economic and, finally, feasible onshore wind potentials. We address each of these potentials in turn, including aspects related to land eligibility criteria, energy meteorology, and technical developments of wind turbine characteristics such as power density, specific rotor power and spacing aspects. Economic aspects of potential assessments are central to future deployment and are discussed on a turbine and system level covering levelized costs depending on locations, and the system integration costs which are often overlooked in such analyses. Non-technical approaches include scenicness assessments of the landscape, constraints due to regulation or public opposition, expert and stakeholder workshops, willingness to pay/accept elicitations and socioeconomic cost-benefit studies. For each of these different potential estimations, the state of the art is critically discussed, with an attempt to derive best practice recommendations and highlight avenues for future research

Exercise and pregnancy in recreational and elite athletes: 2016/17 evidence summary from the IOC Expert Group Meeting, Lausanne. Part 3 - Exercise in the postpartum period

This is Part 3 in the series of reviews from the IOC expert committee on exercise and pregnancy in recreational and elite athletes. Part 1 focused on the effects of training during pregnancy and on the management of common pregnancy-related complaints experienced by athletes1; Part 2 addressed maternal and fetal perinatal outcomes.2 In this part, we review the implications of pregnancy and childbirth on return to exercise and on common illnesses and complaints in the postpartum period. The postpartum period can be divided into hospital-based (during hospital stay), immediate postpartum (hospital discharge to 6 weeks postpartum) and later postpartum (6 weeks to 1 year, corresponding sometimes to cessation of breast feeding).3 In the literature, the postpartum period is usually defined as the first 6 weeks after pregnancy, during which time women have not typically been encouraged to exercise, except for strength training of the pelvic floor muscles. However, 6 weeks is an arbitrary time point and, anecdotally, many elite athletes report starting exercise inside that period. For the purpose of the present review, we consider the postpartum period to be up to 12 months following birth

OPTIMIZATION AND CHARACTERISATION BY FINITE ELEMENT METHOD OF AN ELECTROMECHANICAL ACTAUTOR FOR MORE ELECTRIC AIRCRAFT APPLICATIONS

The future More Electric Aircraft (MEA) technology focus on increasing the use of electrical equipment to a larger extent, e.g. replacing conventional hydraulic and pneumatic actuators with electromechanical or electro hydrostatic actuators to reduce weight, cost and maintenance. Advances in enabling technologies of electric power generation, distribution, and utility equipment have made the use of electric actuators more competitive. Electric actuation can be based on Electro Hydrostatic (EHA), ElectroMechanical (EMA), or Magnetostrictive Actuator (MA) concepts. In this paper the experiences from a performed electromechanical actuator demonstrator program are presented together with a motor optimization method intended for future programs. The described actuator demonstrator is designed for an Unmanned Aerial Vehicle (UAV) application. The important key design criteria’s for the demonstrator have been reliability, redundancy, torque density, and reduced maintenance

Physiological Correlates of Skating Performance in Women's and Men's Ice Hockey

The purpose of the current investigation was to identify relationships between physiological off-ice tests and on-ice performance in female and male ice hockey players on a comparable competitive level. Eleven women, 24 ± 3.0 years, and 10 male ice hockey players, 23 ± 2.4 years, were tested for background variables: height, body weight (BW), ice hockey history, and lean body mass (LBM) and peak torque (PT) of the thigh muscles, [latin capital V with dot above]o2peak and aerobic performance (Onset of Blood Lactate Accumulation [OBLA], respiratory exchange ratio [RER1]) during an incremental bicycle ergometer test. Four different on-ice tests were used to measure ice skating performance. For women, skating time was positively correlated (p &lt; 0.05) to BW and negatively correlated to LBM%, PT/BW, OBLA, RER 1, and [latin capital V with dot above]o2peak (ml O2·kg-1 BW-1·min-1) in the Speed test. Acceleration test was positively correlated to BW and negatively correlated to OBLA and RER 1. For men, correlation analysis revealed only 1 significant correlation where skating time was positively correlated to [latin capital V with dot above]o2peak (L O2·min-1) in the Acceleration test. The male group had significantly higher physiological test values in all variables (absolute and relative to BW) but not in relation to LBM. Selected off-ice tests predict skating performance for women but not for men. The group of women was significantly smaller and had a lower physiological performance than the group of men and were slower in the on-ice performance tests. However, gender differences in off-ice variables were reduced or disappeared when values were related to LBM, indicating a similar capacity of producing strength and aerobic power in female and male hockey players. Skating performance in female hockey players may be improved by increasing thigh muscle strength, oxygen uptake, and relative muscle mass