Development of a balanced experimental–computational approach to understanding the mechanics of proximal femur fractures

The majority of people who sustain hip fractures after a fall to the side would not have been identified using current screening techniques such as areal bone mineral density. Identifying them, however, is essential so that appropriate pharmacological or lifestyle interventions can be implemented. A protocol, demonstrated on a single specimen, is introduced, comprising the following components; in vitro biofidelic drop tower testing of a proximal femur; high-speed image analysis through digital image correlation; detailed accounting of the energy present during the drop tower test; organ level finite element simulations of the drop tower test; micro level finite element simulations of critical volumes of interest in the trabecular bone. Fracture in the femoral specimen initiated in the superior part of the neck. Measured fracture load was 3760 N, compared to 4871 N predicted based on the finite element analysis. Digital image correlation showed compressive surface strains as high as 7.1% prior to fracture. Voxel level results were consistent with high-speed video data and helped identify hidden local structural weaknesses. We found using a drop tower test protocol that a femoral neck fracture can be created with a fall velocity and energy representative of a sideways fall from standing. Additionally, we found that the nested explicit finite element method used allowed us to identify local structural weaknesses associated with femur fracture initiation.

Modelling and Validation of a Mass Imbalance Oscillation Generator to Harvest Heart Motion Energy

An autonomous energy source within a human body is of key importance in the development of medical implants. This work deals with the modelling and the validation of an energy harvesting device which converts the myocardial contractions into electrical energy. The mechanism consists of a clockwork from a commercially available wrist watch. We developed a physical model which is able to predict the total amount of energy generated when applying an external excitation. For the validation of the model, a custom-made hexapod robot was used to accelerate the harvesting device along a given trajectory. We applied forward kinematics to determine the actual motion experienced by the harvesting device. The motion provides translational as well as rotational motion information for accurate simulations in three-dimensional space. The physical model could be successfully validated.

Jatropha mahafalensis for rural energy supply in south-western Madagascar?

In many parts of the eastern African region wood-based fuels will remain dominant sources of energy in coming decades. Pressure on forests, especially in semi-arid areas will therefore continue increasing. In this context, the role of liquid biofuels as substitutes for firewood and charcoal, to help reducing pressure on woody biomass and contributing to a better energy security of rural communities, has remained controversial among researchers and practitioners. At household level, the economic and technical feasibility of straight vegetable oil (SVO) was assessed mainly on Jatropha curcas, with unpersuasive results. So far nothing is known about the suitability as an energy carrier of Jatropha mahafalensis Jum. & H. Perrier, the only endemic representative of the Jatropha genus in Madagascar. This paper explores the potential of this plant as a biofuel feedstock in the agro-pastoral area of Soalara, in the semi-arid south-western part of Madagascar. Only hedge-based production was considered to rule out competition over land with food crops. Yield data, the length of currently existing hedges and energy consumption patterns of households were used to assess the quantitative potential and economic viability of J. mahafalensis SVO for lighting and cooking. Tests were conducted with cooking and lighting devices to assess their technical suitability at household level. The paper concludes that J. mahafalensis hedges have some potential to replace paraffin for lighting (though without much economic benefit for the concerned households), but not to replace charcoal or firewood for cooking. The paper recommends that rural energy strategies in similar contexts do not focus only on substituting current fuels with SVO, but should also take into consideration other alternatives. In the case of cooking, there seems to be substantially more potential in increasing the efficiency of current fuel production and consumption technologies (kilns and stoves); and in the case of lighting, solutions based on SVO need to be compared against other options such as portable solar devices.

Energy Efficient Multimedia Communications in IEEE 802.11 Networks

During the last decade wireless mobile communications have progressively become part of the people’s daily lives, leading users to expect to be “alwaysbest-connected” to the Internet, regardless of their location or time of day. This is indeed motivated by the fact that wireless access networks are increasingly ubiquitous, through different types of service providers, together with an outburst of thoroughly portable devices, namely laptops, tablets, mobile phones, among others. The “anytime and anywhere” connectivity criterion raises new challenges regarding the devices’ battery lifetime management, as energy becomes the most noteworthy restriction of the end-users’ satisfaction. This wireless access context has also stimulated the development of novel multimedia applications with high network demands, although lacking in energy-aware design. Therefore, the relationship between energy consumption and the quality of the multimedia applications perceived by end-users should be carefully investigated. This dissertation addresses energy-efficient multimedia communications in the IEEE 802.11 standard, which is the most widely used wireless access technology. It advances the literature by proposing a unique empirical assessment methodology and new power-saving algorithms, always bearing in mind the end-users’ feedback and evaluating quality perception. The new EViTEQ framework proposed in this thesis, for measuring video transmission quality and energy consumption simultaneously, in an integrated way, reveals the importance of having an empirical and high-accuracy methodology to assess the trade-off between quality and energy consumption, raised by the new end-users’ requirements. Extensive evaluations conducted with the EViTEQ framework revealed its flexibility and capability to accurately report both video transmission quality and energy consumption, as well as to be employed in rigorous investigations of network interface energy consumption patterns, regardless of the wireless access technology. Following the need to enhance the trade-off between energy consumption and application quality, this thesis proposes the Optimized Power save Algorithm for continuous Media Applications (OPAMA). By using the end-users’ feedback to establish a proper trade-off between energy consumption and application performance, OPAMA aims at enhancing the energy efficiency of end-users’ devices accessing the network through IEEE 802.11. OPAMA performance has been thoroughly analyzed within different scenarios and application types, including a simulation study and a real deployment in an Android testbed. When compared with the most popular standard power-saving mechanisms defined in the IEEE 802.11 standard, the obtained results revealed OPAMA’s capability to enhance energy efficiency, while keeping end-users’ Quality of Experience within the defined bounds. Furthermore, OPAMA was optimized to enable superior energy savings in multiple station environments, resulting in a new proposal called Enhanced Power Saving Mechanism for Multiple station Environments (OPAMA-EPS4ME). The results of this thesis highlight the relevance of having a highly accurate methodology to assess energy consumption and application quality when aiming to optimize the trade-off between energy and quality. Additionally, the obtained results based both on simulation and testbed evaluations, show clear benefits from employing userdriven power-saving techniques, such as OPAMA, instead of IEEE 802.11 standard power-saving approaches.

Implications of the sustainable development paradigm for Switzerland

The sustainable development paradigm raises issues of global, intra- and intergenerational social equity as well as respect for nature, and economic welfare. Switzerland is confronted by these issues within its own country, and has a moral responsibility vis-a-vis the rest of the world. Syndromes of global change are affecting many eco-regions, not only in developing and transition countries, but to a lesser extent also the affluent countries. Switzerland as a nation has an impact on syndromes through its far-reaching economic activities, which are non-sustainable. At the global level, more modest consumption patterns, a considerably slowed demographic change, a nonconsumptive but sustainable use of natural resources, and conflict transformation are the main prerequisites for improving sustainability. Switzerland's current contribution to sustainability is much less than what it could be, hence the need for additional action along general principles in,accordance with Swiss traditions and innovative potentials. A number of concrete actions could be taken immediately. These are: labelling the socially and ecologically sustainable production of goods and services, and their negotiation at WTO level; enhancing international cooperation and research; strengthening education and research for sustainability, and emphasizing energy and material flux efficiency at home and abroad.

Energy subsidies from a climate and trade perspective

A short paper for dissemination based on a research piece published by the E15Initiative: Subsidies, Clean Energy, and Climate Change, February 2015. Implemented jointly by ICTSD and the World Economic Forum, the E15Initiative convenes world-class experts and institutions to generate strategic analysis and recommendations for government, business, and civil society geared towards strengthening the global trade and investment system. The paper is also published in Spanish and Portuguese.

Subsidies, Clean Energy, and Climate Change

Estimates show that fossil fuel subsidies average USD 400–600 billion annually worldwide while renewable energy (RE) subsidies amounted to USD 66 billion in 2010 and are predicted to rise to USD 250 billion annually by 2035. Domestic political rationales for energy subsidies include promoting innovation, job creation and economic growth, energy security, and independence. Energy subsidies may also serve social and environmental goals. Whether and to what extent subsidies are effective to achieve these goals or instead lead to market distortions is a matter of much debate and the trade effects of energy subsidies are complex. This paper offers an overview of the types of energy subsidies that are used in the conventional and renewable energy sectors, and their relationship with climate change, in particular greenhouse gas emissions. While the WTO’s Agreement on Subsidies and Countervailing Measures (ASCM) is mostly concerned with harm to competitors, this paper considers the extent to which the Agreement could also discipline subsidies that cause harm to the environment as a global common. Beyond the existing legal framework, this paper surveys a number of alternatives for improving the ability of subsidies disciplines to internalize climate change costs of energy production and consumption. One option is a new multilateral agreement on subsidies or trade remedies (with an appropriate carve-out in the WTO regime to allow for it if such an agreement is concluded outside it). Alternatively, climate change-related subsidies could be included as part of another multilateral regime or as part of regional agreements. A third approach would be to incorporate rules on energy subsidies in sectorial agreements, including a Sustainable Energy Trade Agreement such as has been proposed in other ICTSD studies.