Tidal current power effects on nearby sandbanks: a case study in the Race of Alderney.

A validated numerical model of tidal flows and sediment transport around the Alderney South Banks was used to investigate the potential effects of large (300 MW) tidal turbine arrays at different locations in Alderney territorial waters. Two methods were used, firstly looking at hydrodynamic changes only and secondly modelling sediment transport over a non-erodible bed. The baseline hydrodynamic model was validated relative to ADCP velocity data collected in the immediate vicinity of the sandbank. Real-world sand transport rates were inferred from sand-wave migrations and agree favourably with sediment transport residuals calculated from model outputs. Outputs from the sediment model reproduced realistic morphological behaviours over the bank. Seventeen different locations were considered; most did not result in significant hydrodynamic changes over the South Banks; however, three array locations were singled out as requiring extra caution if development were to occur. The results provide a case for optimizing the array locations for twin objectives of maximizing array power and minimizing impacts on the sandbanks. This article is part of the theme issue 'New insights on tidal dynamics and tidal energy harvesting in the Alderney Race'.

Dataset of the livability performance of the city of Birmingham, UK, as measured by its citizen wellbeing, resource security, resource efficiency and carbon emissions.

This data article presents the UK City LIFE1 data set for the city of Birmingham, UK. UK City LIFE1 is a new, comprehensive and holistic method for measuring the livable sustainability performance of UK cities. The Birmingham data set comprises 346 indicators structured simultaneously (1) within a four-tier, outcome-based framework in order to aid in their interpretation (e.g., promote healthy living and healthy long lives, minimize energy use, uncouple economic vitality from CO2 emissions) and (2) thematically in order to complement government and disciplinary siloes (e.g., health, energy, economy, climate change). Birmingham data for the indicators are presented within an Excel spreadsheet with their type, units, geographic area, year, source, link to secondary data files, data collection method, data availability and any relevant calculations and notes. This paper provides a detailed description of UK city LIFE1 in order to enable comparable data sets to be produced for other UK cities. The Birmingham data set is made publically available at http://epapers.bham.ac.uk/3040/ to facilitate this and to enable further analyses. The UK City LIFE1 Birmingham data set has been used to understand what is known and what is not known about the livable sustainability performance of the city and to inform how Birmingham City Council can take action now to improve its understanding and its performance into the future (see "Improving city-scale measures of livable sustainability: A study of urban measurement and assessment through application to the city of Birmingham, UK" Leach et al. [2]).

Infrastructural challenges to better health in maternity facilities in rural Kenya: community and healthworker perceptions.

BACKGROUND: The efforts and commitments to accelerate progress towards the Millennium Development Goals for maternal and newborn health (MDGs 4 and 5) in low and middle income countries have focused primarily on providing key medical interventions at maternity facilities to save the lives of women at the time of childbirth, as well as their babies. However, in most rural communities in sub-Saharan, access to maternal and newborn care services is still limited and even where services are available they often lack the infrastructural prerequisites to function at the very basic level in providing essential routine health care services, let alone emergency care. Lists of essential interventions for normal and complicated childbirth, do not take into account these prerequisites, thus the needs of most health facilities in rural communities are ignored, although there is enough evidence that maternal and newborn deaths continue to remain unacceptably high in these areas. METHODS: This study uses data gathered through qualitative interviews in Kitonyoni and Mwania sub-locations of Makueni County in Eastern Kenya to understand community and provider perceptions of the obstacles faced in providing and accessing maternal and newborn care at health facilities in their localities. RESULTS: The study finds that the community perceives various challenges, most of which are infrastructural, including lack of electricity, water and poor roads that adversely impact the provision and access to essential life-saving maternal and newborn care services in the two sub-locations. CONCLUSIONS: The findings and recommendations from this study are important for the attention of policy makers and programme managers in order to improve the state of lower-tier health facilities serving rural communities and to strengthen infrastructure with the aim of making basic routine and emergency obstetric and newborn care services more accessible.

Marine current energy conversion: the dawn of a new era in electricity production.

Marine currents can carry large amounts of energy, largely driven by the tides, which are a consequence of the gravitational effects of the planetary motion of the Earth, the Moon and the Sun. Augmented flow velocities can be found where the underwater topography (bathymetry) in straits between islands and the mainland or in shallows around headlands plays a major role in enhancing the flow velocities, resulting in appreciable kinetic energy. At some of these sites where practical flows are more than 1 m s(-1), marine current energy conversion is considered to be economically viable. This study describes the salient issues related to the exploitation of marine currents for electricity production, resource assessment, the conversion technologies and the status of leading projects in the field. This study also summarizes important issues related to site development and some of the approaches currently being undertaken to inform device and array development. This study concludes that, given the highlighted commitments to establish favourable regulatory and incentive regimes as well as the aspiration for energy independence and combating climate change, the progress to multi-megawatt arrays will be much faster than that achieved for wind energy development.

Tribological design constraints of marine renewable energy systems.

Against the backdrop of increasing energy demands, the threat of climate change and dwindling fuel reserves, finding reliable, diverse, sustainable/renewable, affordable energy resources has become a priority for many countries. Marine energy conversion systems are at the forefront of providing such a resource. Most marine renewable energy conversion systems require tribological components to convert wind or tidal streams to rotational motion for generating electricity while wave machines typically use oscillating hinge or piston within cylinder geometries to promote reciprocating linear motion. This paper looks at the tribology of three green marine energy systems, offshore wind, tidal and wave machines. Areas covered include lubrication and contamination, bearing and gearbox issues, biofouling, cavitation erosion, tribocorrosion, condition monitoring as well as design trends and loading conditions associated with tribological components. Current research thrusts are highlighted along with areas needing research as well as addressing present-day issues related to the tribology of offshore energy conversion technologies.