Development of manufacturability constraints for press forming of sheet metal components

http://www.worldcat.org/oclc/2869757

Measuring the solar potential of a city and its implications on energy policy

This research investigates the maximum potential energy that can be made available by efficiently installing PV systems on buildings throughout a city, from the central business district (CBD) out to low density suburbs. The purpose of this is to evaluate the contribution that electricity from PVs can make to reduce the electricity load of a city, supply the needs of a mixture of building types, reduce peak electricity demand and contribute towards the charging of electric vehicles (EVs). A sample of the main urban building types have been taken and reassembled into a representative typical cross-section of a city. The application of PVs for all the building types is investigated and then the potential electricity distribution is evaluated for different urban densities and dispersion patterns. This research is concerned not only with how individual buildings may gain from distributed generation (DG) but, more importantly, how a city as a whole may benefit. The results indicate that low dense suburbia is not only the most efficient collector of solar energy but that enough excess electricity can be generated to power daily transport needs of suburbia and also contribute to peak daytime electrical loads in the city centre. This challenges conventional thinking that suburbia is energy inefficient. While a compact city may be more efficient for the internal combustion engine vehicles, a dispersed city is more efficient when DG solar power is the main energy source and EVs are the means of transport

Bio-inspired variable-stiffness flaps for hybrid flow control, tuned via reinforcement learning

A bio-inspired, passively deployable flap attached to an airfoil by a torsional spring of fixed stiffness can provide significant lift improvements at post-stall angles of attack. In this work, we describe a hybrid active-passive variant to this purely passive flow control paradigm, where the stiffness of the hinge is actively varied in time to yield passive fluid-structure interaction (FSI) of greater aerodynamic benefit than the fixed-stiffness case. This hybrid active-passive flow control strategy could potentially be implemented using variable stiffness actuators with less expense compared with actively prescribing the flap motion. The hinge stiffness is varied via a reinforcement learning (RL)-trained closed-loop feedback controller. A physics-based penalty and a long-short-term training strategy for enabling fast training of the hybrid controller are introduced. The hybrid controller is shown to provide lift improvements as high as 136\% and 85\% with respect to the flap-less airfoil and the best fixed-stiffness case, respectively. These lift improvements are achieved due to large-amplitude flap oscillations as the stiffness varies over four orders of magnitude, whose interplay with the flow is analyzed in detail

Incorporating voltage security into the planning, operation and monitoring of restructured electric energy markets

As open access market principles are applied to power systems, significant changes are happening in their planning, operation and control. In the emerging marketplace, systems are operating under higher loading conditions as markets focus greater attention to operating costs than stability and security margins. Since operating stability is a basic requirement for any power system, there is need for newer tools to ensure stability and security margins being strictly enforced in the competitive marketplace. This dissertation investigates issues associated with incorporating voltage security into the unbundled operating environment of electricity markets. It includes addressing voltage security in the monitoring, operational and planning horizons of restructured power system. This dissertation presents a new decomposition procedure to estimate voltage security usage by transactions. The procedure follows physical law and uses an index that can be monitored knowing the state of the system. The expression derived is based on composite market coordination models that have both PoolCo and OpCo transactions, in a shared stressed transmission grid. Our procedure is able to equitably distinguish the impacts of individual transactions on voltage stability, at load buses, in a simple and fast manner. This dissertation formulates a new voltage stability constrained optimal power flow (VSCOPF) using a simple voltage security index. In modern planning, composite power system reliability analysis that encompasses both adequacy and security issues is being developed. We have illustrated the applicability of our VSCOPF into composite reliability analysis. This dissertation also delves into the various applications of voltage security index. Increasingly, FACT devices are being used in restructured markets to mitigate a variety of operational problems. Their control effects on voltage security would be demonstrated using our VSCOPF procedure. Further, this dissertation investigates the application of steady state voltage stability index to detect potential dynamic voltage collapse. Finally, this dissertation examines developments in representation, standardization, communication and exchange of power system data. Power system data is the key input to all analytical engines for system operation, monitoring and control. Data exchange and dissemination could impact voltage security evaluation and therefore needs to be critically examined

Transported snapshot model order reduction approach for parametric, steady-state fluid flows containing parameter dependent shocks

In this thesis, a new model order reduction approach is proposed for parametric steady-state nonlinear fluid flows characterized by shocks and discontinuities whose spatial locations and orientations are strongly parameter dependent. In this method, solutions in the predictive regime are approximated using a linear superposition of parameter-dependent basis. The sought after parametric reduced-basis arise from solutions of linear transport equations. Key to the proposed approach is the observation that the optimal transport velocities are typically smooth and continuous, despite the solution themselves not being so. As a result, the transport fields can be accurately expressed using a low-order polynomial expansion. Similar to traditional projection-based model order reduction approaches, the proposed method is formulated mathematically as a residual minimization problem for the generalized coordinates. The method is successfully applied to the reduction of a parametric 1-D flow in a converging-diverging nozzle, a parametric 2-D supersonic flow over a forward facing step and a parametric 2-D jet diffusion flame in a combustor

Are probiotics a feasible intervention for prevention of diarrhoea in the developing world?

With more than 1.4 million of the 9 million child deaths being attributed to diarrhoea in 2008 and 49% of them occurring in five countries namely, India, Nigeria, Democratic Republic of the Congo, Pakistan and China, there is an urgent need for intervention to prevent and control diarrhoeal diseases. Of the various interventions, probiotics offer immense potential. The past decade has witnessed the validation of their utility for the prevention, treatment and management of a variety of infective and non infective disorders. The most investigated field continues to remain infectious diarrhoea and compelling evidence comes from randomized placebo controlled trials. While results from these studies are encouraging most of them reflect the outcomes of the developed world. Developing countries like India continue to struggle with nutritional and health challenges and bear the greatest burden of diarrhoea. A paucity of data from the developing countries limits the definite recommendation of probiotics. In these countries curd, often confused for a probiotic, is practiced as an integral part of the culture. While the nutritional benefits of these products cannot be understated, it is still uncertain whether these products can be classified as a probiotic. The emergence of probiotic foods which are scientifically validated for their efficacy and impart defined health benefits offer an excellent opportunity to improve public health. A recent randomized controlled trial conducted by the National Institute of Cholera and Enteric Diseases in Kolkata, India demonstrated a protective efficacy of 14% in preventing diarrhoea among children who received a probiotic. For the developing world however the vision for probiotics would mean a fundamental change in perception and developing a well planned strategy to allow interventions like probiotics to permeate to impoverished settings, where the assault of micro organisms is on a daily basis. This would mean that probiotics are ingrained into the public health system without being seen as a medicine

Health impact of probiotics - vision and opportunities

Our understanding of the role of the microbiota in our gut and other sites in our body is rapidly emerging and could lead to many new and innovative approaches for health care. The promise of the potential role of probiotics for the prevention and treatment of enteric and other infections as an effective solution needs to be realized. The meeting report summarizes the insights and learning from a recent symposium, "Health Impact of Probiotics - Vision and Opportunities" conducted in Mumbai by the Yakult India Microbiota and Probiotic Science Foundation and P.D. Hinduja National Hospital, Mumbai. The symposium reflected its objective of unraveling the potential role of probiotics for health benefits through presentations and discussions. Experts clearly highlighted the role of probiotics in improving various aspects of health and in immune modulation. The report also captures the debate and discussions on the challenges that are likely to be encountered for the use of probiotics in the country