bluuebunny/crossref_metadata_2025 huggingface dataset:
Nature Teaching Structures
Authors: Wester Ture
Published: March 2010

If one is looking for an example of a conceptual design which is extremely appropriate in its morphology, well adapted to the surroundings, structurally and functionally optimised, and has a refined and appropriate appearance – all in one single configuration – you have either an exceptional and rare piece of fine architecture – or a common organism in Nature. That is why Nature makes an excellent object for architectural students to study structures from a conceptual and a morphological point of view. And that is why Nature – who has developed her structural systems by trial-and-error through millions of years – acts as an excellent teacher of these topics. At the same time, the idiom of Nature seems to possess a considerable attraction for students and is able to convey inspiration and imagination to the creative process of shaping architectural structures. In our surrounding living and nonliving nature a number of striking statical and kinematical peculiarities have been observed. The paper will try to isolate and describe some of these observations and their relation to our engineered structures based on human thinking. The paper will deal with basic aspects as geometry, topology, redundancy and kinematic stability of structures in Nature and in architecture.
Studies in Structural Concepts: An Introduction to Spatial Structures
Authors: Srivastava N. K.
Published: March 2010

The paper deals with teaching structural concepts as a first course in undergraduate structural engineering. The course is an attempt to initiate and introduce spatial thinking and to prepare a student to visualise and create by means of physical modelling, graphical modelling and simplified analytical or computer modelling of structural systems in 3D space and their components. The paper includes the desired objectives, the attempted approach, details of the content, some experiences of teaching such a course and a few suggestions for improvement.
Teaching of Morphology
Authors: Chassagnoux Alain , Dudon Michel , Aubry Didier , Chassagnoux J. , Chomarat A. , Diacon C. , Miguet F. , Savel J.
Published: March 2010

The concept of form is central to the process of architectural creation. In the contemporary conditions where architects enjoy a great formal liberty, by lack of any corpus and the development of powerful tools, it is important to teach science of form in the faculties of architecture. The Ecole d'Architecture de Nantes has developed an original teaching of morphology, based on three axes: theory, simulation by physical and/or numerical models and experimentation on a larger scale. A workshop machine tool and specific teaching materials have been developed in order to give students rapid access to complex models.
A Techno-Economic Analysis of a Proposed 1.5 MW Wind Turbine with a Hydrostatic Drive Train
Authors: Browning James R. , Manwell James F. , McGowan Jon G.
Published: March 2010

This paper presents a techno-economic feasibility study for a proposed 1.5 MW wind turbine utilizing a continuously variable ratio hydrostatic drive train between the rotor and the generator. The estimated cost of energy is compared to that of a conventional wind turbine of equivalent rated power. The annual energy production is estimated for the hydrostatic turbine using an assumed wind speed distribution and a turbine power curve resulting from a steady state performance model of the turbine. The initial capital cost of the turbine is estimated using cost models developed for various components unique to the hydrostatic turbine as well as economic parameters and models developed by the National Renewable Energy Lab (NREL) in the WindPACT advanced wind turbine drive train study. The resulting cost of energy, along with various performance characteristics of interest, are presented and compared to those of the WindPACT baseline turbine intended to represent a conventional utility scale wind turbine.
Design of Dual Mode Linguistic Hedge Fuzzy Logic Controller for an Isolated Wind-Diesel Hybrid Power System with Lossy Magnetic Energy Storage Unit
Authors: Ansari M. Md. Thameem , Velusami S.
Published: March 2010

In this paper, a dual mode linguistic hedge fuzzy logic controller for an isolated wind-diesel hybrid power system with lossy magnetic energy storage unit is proposed. The design methodology is a hybrid model based on the concepts of dual mode control, the linguistic hedges and the hybrid genetic algorithm-simulated annealing algorithms. The system is simulated with the dual mode linguistic hedge fuzzy logic controller and the frequency deviation resulting from the step load disturbance is presented. It is observed from the result that with the application of the proposed controller, the system performance is improved significantly. It has been also found that the proposed controller is less sensitive to the changes in the parameters of the system and also under different operating modes of the hybrid power system.
Environmental Regulations and Interfuel Substitution in the Power Sector: A Generalized Leontief Model
Authors: Söderholm Patrik
Published: March 2010

This paper analyzes short-run interfuel substitution between fossil fuels in West European power generation, and the impact of SO2 regulations on fossil fuel choices. These problems are studied within a short-run Generalized Leontief cost function. The empirical results indicate that price-induced interfuel substitution in existing power plants is substantial in West Europe, especially that between oil and gas. This is consistent with the notion that short-run fuel substitution primarily occurs in multi-fired plants, by switching load between different single-fired plants, and/or by converting power plants to be able to burn alternate fuels as well. With regard to the impact of the SO2 regulations, the empirical investigation provides few conclusive answers. In general it is hard to separate the individual effects of the SO2 regulations on the one hand, and other fuel affecting policies on the other. Still, during the last 20 years the aggregate effect of public energy policies seems to have been coal and gas promoting and oil discouraging.
The Impact of Oil Price Volatility on the Future of the U.S. Economy
Authors: Boyd Roy , Doroodian K. , Thornton Dennis
Published: March 2010

This paper examines the impact of a foreign oil price shock on domestic energy markets as well as the U.S. economy as a whole. The analytical approach employed in the analysis consisted of a dynamic CGE model composed of eight production sectors, eight consumption sectors, three household categories classified by income, foreign sector, and the government. The results show that oil price shocks will have, as expected, a significantly positive effect on crude oil production. We also find that such price shocks negatively affect the refinery sector as input costs rise there. A decline in per-well productivity has the effect of dampening the rise in crude oil extraction and causing a further decline in refinery output. Economy-wide, the impact of a new series of oil price shocks is quite limited with overall welfare falling, but nowhere near the levels experienced in the 1970s and early 1980s.
Thermophotovoltaics: Can They Make a Significant Contribution?
Authors: Haywood S.K.
Published: March 2010

Recently, a number of research initiatives have focused on thermophotovoltaic (TPV) cells as a means of generating electricity from infra-red radiation. This may be from waste heat, as in the hybrid car which uses TPV technology to charge its battery, or it may involve co-generation of electricity from processes where heat is the primary product. One example is the provision of electrical power from the burner of a domestic boiler in a remote location. In this article, the principles of TPV technology are outlined and its present capabilities discussed. An analysis is made of the efficiency that can be achieved now and in the future and the cost of implementing the technology for different applications. The potential of TPV for domestic, space and military applications is discussed.
Musical Chairs in Power Engineering: Could the Environment Be Left Standing?
Authors: Thomas Steve
Published: March 2010

Concentration in the power engineering business is increasing and nuclear assets are being sold cheaply. Who is buying what and is there an environmental dimension? This view point piece provides recent facts and some speculation.
AIR Quality Management: Challenges and Solutions in Delivering Air Quality Action Plans
Authors: Beattie C. I. , Longhurst J. W. S. , Woodfield N. K.
Published: March 2010

The Air Quality Strategy for England, Scotland, Wales and Northern Ireland (DETR, 20001) has the aim of showing how improved local air quality in the UK may be delivered. Through a process of reviewing and assessing local air quality in both urban and rural localities, a clear picture is emerging of areas of the UK where air quality objectives are not likely to be met. The next challenge will be the identification of the required actions and new ways of working to achieve specific air quality objectives. The declaration of air quality management areas, where objectives are not predicted to be met by their target years, involves co-ordinated local action and collaborative working, which can only be effective with support across local authority departments and external stakeholders. This paper provides a background to the relevant legislation underpinning local air quality management and summarises the review and assessment process. It then comments on future directions in relation to the designation of Air Quality Management Areas and considers the requirements of action plans to deliver the goal of cleaner air in the UK. It is concluded that the UK has developed a highly sophisticated system of air quality management over a relatively short period of time, and with it has brought a new way of local authority working. The challenge of the next stage of the process is likely to be in implementing cost effective and proportional solutions to identified problems at the local level.
Methane Mitigation Conference Report
Authors: Schultz Karl H
Published: March 2010

The Second International Methane Mitigation Conference, held June 18–23, 2000, in Novosibirsk, Russia, drew 200 participants from nearly 30 countries to address opportunities and issues related to methane mitigation. Methane is a potent greenhouse gas, and, depending on the source, implementing reduction strategies can improve operational efficiency, provide a viable energy source, or improve agricultural productivity. During the conference, participants developed a stronger understanding of the specific measures that can lead to the most pragmatic and cost-effective emission reductions, and set forth recommendations to improve conditions for the development of projects.

The Conference, jointly organized by the Russian Academy of Sciences and the U.S. Environmental Protection Agency, with co-sponsorship by a number of private and governmental bodies, included presentations on a variety of topics related to greater project realization, such as project finance, markets for emission credits, institutional barriers, technical options, and project opportunities. During the conference's source-specific technical sessions, participants shared information and experiences on mitigating methane emissions from coal mining, natural gas systems, solid waste landfills, and agricultural and natural sources. This exchange of information was further developed during field trips, where conference participants had the opportunity to visit methane sources in southwestern Siberia, and to meet with local experts to discuss technical merits of different methane mitigation measures. Throughout the conference, participants were asked to seek answers to these four basic questions: 1) Analyses indicate that methane mitigation is often very cost-effective. What steps are necessary for greater project realization? 2) International institutions are looking for greenhouse gas reduction projects that are reliable and measurable. How well do methane mitigation projects meet these criteria, and what work needs to be undertaken to make this clear? 3) How are technical advances impacting project attractiveness? What is in store for the future? 4) What roles can industry, governments, multi-lateral institutions, and researchers play to promote methane mitigation? What collaborative efforts should be undertaken?

At the end of each source-specific technical session, participants gathered to formulate findings, conclusions, and recommendations to present during the concluding plenary session. These recommendations are presented in the next section.
Is the Enhancement of Global Warming Important?
Authors: Symons Martyn C. R. , Barrett Jack
Published: March 2010

There is no doubt that global warming [1] is important; without it the Earth's surface would have a mean temperature of 33°C lower than it has currently. The IPCC [2] maintains that human activities are to blame for the observed increase in the concentration of carbon dioxide in the atmosphere since pre-industrial times. There are some doubts about whether global warming is being enhanced by the activities of the human race. This article reviews these doubts and the proposed remedies to the alleged enhancement.
Crystal Balls, Virtual Realities and ‘Storylines’
Authors: Courtney Richard S
Published: March 2010

“Projections” of anthropogenic climate change reported in the Third Assessment Report (TAR) of the UN Intergovernmental Panel on Climate Change (IPCC) are assessed to be based on pseudo-science.
Views on Methane Hydrate for Zero-Emission Energy
Authors: Kikuchi Ryunosuke
Published: March 2010

Application of a fuel cell whose energy source is hydrogen and oxygen is considered useful and even desirable, but hydrogen is not easy to obtain. Though methane hydrate reserves are abundant and are distributed worldwide, they have not yet been well utilized. This paper discusses the concept of devising a practical fuel cell by combining the idea of applying a catalyst to fuel cells with a proposal for developing methane hydrate reserves in order to reduce the dependence on current fossil fuels and cut polluting emissions. Even if the methane hydrate exploitation should not prove feasible, the use of a chemical reaction converting methane to hydrogen without greenhouse gas formation would be extremely beneficial because natural gas consists primarily of methane, and worldwide application of the proposed catalytic process can reduce significantly the generation of greenhouse gases.
Nuclear Power in the UK Electricity Market: From a Limited Future to Eternal Life and Back Again?
Authors: Thomas Steve
Published: March 2010

In 1990, the privatisation of the British electricity supply industry revealed how uneconomic Britain's nuclear power plants were. The nuclear sector was withdrawn from privatisation and it seemed likely that by 2000, most of Britain's nuclear power plants would be closed. However, operating costs were dramatically reduced and in 1996, most of the nuclear plants were privatised in British Energy. Nuclear output made an important contribution to the reduction of greenhouse gas emissions and the future looked secure for the existing plants. However, the early success of British Energy was based on an inflated wholesale electricity price and by 2000, British Energy was struggling to cover its costs. The British government is now conducting a review of energy policy. The economic case for new nuclear power plants is poor but the need to meet greenhouse gas emission targets and the influence British Energy and BNFL may ensure the long-term future of the existing plants.
Key Aspects of Global Climate Change
Authors: Kondratyev K. Ya.
Published: March 2010

As a contribution to the World Climate Change Conference (WCCC 2003, Moscow September 29 – October 3), an analysis was made of the key issues in the scientific understanding of contemporary global climate change. The focus of this analysis is a discussion of the uncertainties relating to existing observational data and of the results of numerical modelling. The necessity for analysing current models for their ability to simulate real climate change is emphasized. Real climate change results from the non-linear interactions between numerous components of the climatic system, also taking into account potential contributions from cosmic factors such as solar activity. It is concluded that current models are unable to simulate real climate adequately and should not be used for policy-making predicated on future ‘predicted’ climate.
A 2004 View of the Kyoto Protocol
Authors: Singer Fred
Published: March 2010

It may not be a household word, but by now the Kyoto Protocol has become a well-known political slogan. It is either “fundamentally flawed” (George W. Bush) or it is essential for saving the climate and humanity (Al Gore). There seems to be no in between. The Kyoto Protocol is a treaty to limit (i.e., ration) the use of energy to satisfy the concerns of environmental groups and other believers in global warming catastrophes. This group includes not only certified kooks but also such notables as former Treasury Secretary Paul O'Neill and Sir David King, chief scientific adviser to Her Majesty's government who equates the threat of warming with that of international terrorism. But Kyoto is quite ineffective, that is, it cannot really affect climate or even change the composition of the atmosphere. It is costly. And it is probably also defunct.

Where did this treaty come from? Why is it being adopted by some countries but not by others? And what is its likely future?
Productivity Effects of Technology Diffusion Induced by an Energy Tax
Authors: Walz Rainer
Published: March 2010

In the political discussion, the economy-wide effects of an energy tax have gained considerable attention. So far, macroeconomic analyses have focused on either (positive or negative) costs triggered by an energy tax, or on the efficiency gains resulting from new energy taxes combined with lower distortionary taxes. By contrast, the innovative effects of climate protection measures have not yet been thoroughly analysed. This paper explores the productivity effects of a 50 per cent energy tax in the German industry sector employing a technology-based, three-step bottom-up approach. In the first step, the extensive IKARUS database is used to identify the technological adjustments arising from an energy tax. In the second step, the technologies are classified into different clusters. In the third step, the productivity effects generated by the technological adjustments are examined. The results imply that an energy tax induces mainly sector-specific and process-integrated technologies rather than add-on and cross-cutting technologies. Further, it is shown that the energy-saving technologies tend to increase productivity. This is particularly the case for process-integrated, sector-specific technologies.
Ecological Modernisation in UK Science-Policy Communities: The Case of Acid Rain and Critical Loads
Authors: Tickle A.K.
Published: March 2010

This paper attempts to follow the political resolution of uncertainty within the acid rain debate in relation to science-policy processes in the UK from 1970 to the present day. It is suggested that the emergence of an epistemic community of scientists, policy-makers, and NGOs cohering around the key concept of critical loads, has been a necessary condition for the evolution of ecomodernist air pollution control policies. Finally it is suggested that although the epistemic community has been influential in diffusing critical loads-based approaches to air pollution control within the major supranational environmental regimes in Europe (the UN ECE and European Community), structural political and economic factors still remain the most important drivers of final policy.
Designing Effective Environmental Regimes: The Case of the Convention on Long-Range Transboundary Air Pollution (CLRTAP)
Authors: Wettestad Jørgen
Published: March 2010

This paper analyses the impact of the design of the UNECE Convention on Long-Range Transboundary Air Pollution (CLRTAP) on the control of transboundary air pollution in Europe. The history of CLTRAP is reviewed briefly: its origin as part of the East-West détente process of the 1970's has had considerable influence on its design. Germany's shift from environmental laggard to environmental leader in 1982 had a crucial impact on the effectiveness of the regime. Although transboundary air pollution in Europe has been reduced considerably, it is considered that the CLTRAP regime was only moderately effective in promoting this: much of it would have happened anyway. It has, however, been very effective in raising awareness of air pollution issues and providing a negotiating forum. [Abstract supplied by editor].
A Unified Approach to Some Recent Developments in Jet Noise Theory
Authors: Goldstein M.E.
Published: March 2010

There have been a number of recent developments in the theory of jet noise, many of which are generalizations of Lighthill's original acoustic analogy approach. The purpose of this article is to derive a generic set of equations that provides a structure for reviewing and categorizing these ideas.
Experimental Design Methods — A Review
Authors: Achten Henri H.
Published: March 2010

Experimental design methods are applied in all phases of the design process and by almost every party involved in the design process. In this paper, we aim to give an overview of the background, applications, and technologies involved. A limited simple metric is introduced for assessing the degree of innovation. Future developments are outlined.
Approximation of Poles and Branch Points of Solutions to Certain Nonlinear Differential Equations Using Modified Piecewise Pade Approximations
Authors: From S. G. , Maloney J. P.
Published: March 2010

A simple method is presented to numerically approximate the location of poles and branch point singularities of solutions to certain nonlinear differential equations. The general method uses a modified piecewise-Pade type of approximation. The formulas greatly simplify in the case of second order nonlinear differential equations. Several numerical examples are presented which demonstrate the ease of implementation and efficiency of the methods.
Understanding Cavity Flows Using Proper Orthogonal Decomposition and Signal Processing
Authors: Lawson S.J. , Barakos G.N. , Simpson A.
Published: March 2010

Computational Fluid Dynamics (CFD) is increasingly being used to analyse complex flows. However, to perform a comprehensive analysis over a given time period, a large amount of data is provided and therefore a method for reducing the storage requirements is considered. The Proper Orthogonal Decomposition (POD) is a widely used technique that obtains low–dimensional approximate descriptions of high–dimensional processes. To demonstrate the potential for reduction in data storage, and the potential use of POD in CFD, the cavity flow case is used. This case is a challenge for CFD due to its unsteady nature and high frequency content. The POD modes were constructed using flow–field snapshots taken at regular intervals. Spatial POD modes for the cavity case showed that the modes came in pairs with a 90° phase shift. The lower modes represented the large dynamics of the shear layer and the higher modes the small scale turbulent structures. Reconstructions of the flow–fields showed that the very large dynamics could be represented with as few as 11 modes. However, approximately 101 modes (85% of the flow energy) were needed to approximate the frequency spectra below 1 kHz. Therfore a reduction of 70% in disk storage would be achieved over storing the complete set of flow–field snapshots produced by CFD.
Simulation of Axial Combustion Instability Development and Suppression in Solid Rocket Motors
Authors: Greatrix David R.
Published: March 2010

In the design of solid-propellant rocket motors, the ability to understand and predict the expected behaviour of a given motor under unsteady conditions is important. Research towards predicting, quantifying, and ultimately suppressing undesirable strong transient axial combustion instability symptoms necessitates a comprehensive numerical model for internal ballistic simulation under dynamic flow and combustion conditions. An updated numerical model incorporating recent developments in predicting negative and positive erosive burning, and transient, frequency-dependent combustion response, in conjunction with pressure-dependent and acceleration-dependent burning, is applied to the investigation of instability-related behaviour in a small cylindrical-grain motor. Pertinent key factors, like the initial pressure disturbance magnitude and the propellant's net surface heat release, are evaluated with respect to their influence on the production of instability symptoms. Two traditional suppression techniques, axial transitions in grain geometry and inert particle loading, are in turn evaluated with respect to suppressing these axial instability symptoms.
Dynamics of Practical Premixed Flames, Part I: Model Structure and Identification
Authors: Huber A. , Polifke W.
Published: March 2010

For the analysis of thermoacoustic instabilities it is most important to determine the dynamic flame response to acoustic disturbances. Premixed flames are often modelled as single-input single-output system, where the “output” (the overall rate of heat release) responds to a single “input” variable (often the velocity at the exit of the burner nozzle). However, for practical premixed flames, where perturbations of pressure or velocity at the fuel injector will modulate the fuel equivalence ratio, the heat release rate will respond to fluctuations of equivalence ratio as well as nozzle mass flow rate. In this case, a multiple-input, single-output (MISO) model structure for the flame is appropriate. Such a model structure is developed in the present paper. Staged fuel injection as well as fuel line impedances can be taken into account, the integration with low-order or finite-element based models for stability analysis is straightforward.

In order to determine unit impulse and frequency response functions for such a model structure, an identification scheme based on unsteady CFD calculation with broadband excitation followed by correlation analysis is proposed and validated successfully. Identification of MISO model coefficients is a challenging task, especially in the presence of noise. Therefore criteria are introduced which allow to ascertain a posteriori how well the identified model represents the true system dynamics. Using these criteria, it is investigated how excitation signal type, time series length and signal-to-noise ratio influence the results of the identification process.

Consequences for passive design strategies based on multi-stage fuel injection and experimental work on practical premixed flame dynamics are discussed.
Validation of a Grid Independent Spray Model and Fuel Chemistry Mechanism for Low Temperature Diesel Combustion
Authors: Yoshikawa Takeshi , Reitz Rolf D.
Published: March 2010

Spray and combustion submodels used in a Computational Fluid Dynamics (CFD) code, KIVACHEMKIN, were validated for Low Temperature Combustion (LTC) in a diesel engine by comparing measured and model predicted fuel spray penetrations, and in-cylinder distributions of OH and soot. The conditions considered were long ignition delay, early and late fuel injection cases. It was found that use of a grid independent spray model, called the GASJET model, with an improved n-heptane chemistry mechanism can well predict the heat release rate, not only of the main combustion stage, but also of the cool flame stage. Additionally, the GASJET model appropriately predicts the distributions of OH and soot in the cylinder even when the resolution of the computational mesh is decreased by half, which significantly reduces the required computational time.
Critical Slow Dynamics of Detonation in a Gas with Non-Uniform Initial Temperature and Composition: A Large-Activation-Energy Analysis
Authors: Vidal Pierre
Published: March 2010

We study the dynamic conditions of existence of the self-sustained detonation regime in gases with non-uniform initial temperature and dilution in the case where the gradients of initial state are parallel to the propagation direction. We analyze the slow dynamics of the detonation supposing that the initial variations have the same order of smallness as the unsteadiness and curvature of the leading shock of the detonation front. We obtain a hyperbolic evolution law for the detonation shock front as a solution to an eigenvalue problem solved in the asymptotic limit of large activation energies for which the induction time of the chemical decomposition process is considered much larger than the heat-release time. We study the effect of the shock dynamics of this self-sustained detonation front on the induction time and we integrate the evolution law for some examples of distinct or combined, dispersive or localized, initial variations in the temperature and diluent mass fraction. We show the existence of a bifurcation set of initial conditions that separates the self-sustained detonations that will continuously achieve the CJ regime from those whose dynamics eventually fail to initiate the chemical decomposition because the dynamic induction length becomes too long. We find that the characteristic critical lengths associated with the initial or boundary conditions are larger than the reference CJ characteristic chemical length by several orders of magnitude, a well-established experimental feature of gaseous detonations. We identify subcritical and supercritical limits which, respectively, give necessary and sufficient conditions for detonation. Below the subcritical limit, the combustion front cannot be coupled to the shock front because the volumetric expansion rate behind the shock is too large. Above the supercritical limit, the relaxation from an overdriven detonation regime to the self-sustained regime is a continuous process, without decoupling and recoupling of the combustion and shock fronts. We interpret the critical domain between these limits as the parametric zone in which experiments show successive decouplings and transverse recouplings of the combustion and shock fronts before the final self-sustained CJ regime.
Performance Flight Testing of Small, Electric Powered Unmanned Aerial Vehicles
Authors: Ostler Jon N. , Bowman W. Jerry , Snyder Deryl O. , McLain Timothy W.
Published: March 2010

Flight testing methods are developed to find the drag polar for small unmanned aerial vehicles powered by electric motors with fixed-pitch propellers. Wind tunnel testing was used to characterize the propeller-motor efficiency. The drag polar was constructed using data from flight tests. This drag polar was then used to find the following performance parameters: maximum velocity, minimum velocity, velocity for maximum range, velocity for maximum endurance, maximum rate of climb, maximum climb angle, minimum turn radius, maximum turn rate, and maximum bank angle. The developed flight testing methods are used to characterize the performance of a small UAV.
High-Amplitude Pitch of a Flat Plate: An Abstraction of Perching and Flapping
Authors: Ol Michael V. , Eldredge Jeff D. , Wang Chengjie
Published: March 2010

We compare water tunnel experiment and 2D vortex-particle computation for a generalization of the classical problem of flat-plate constant-rate pitch and related motions, at frequencies and Reynolds numbers relevant to Micro Air Vehicle applications. The motivation is problems of maneuvering, perching and gust response. All of the examined flows evince a strong leading edge vortex. Increasing pitch rate tends to tighten the leading edge vortex and to produce a trailing-edge vortex system dominated by a counter-rotating pair. Pitch pivot point location is crucial to the leading edge vortex size and formation history, and to its subsequent behavior in convecting over the airfoil suction-side. Despite the respective limitations of the experiment and computations, agreement in vorticity fields between the two at an overlapping case at Re = 10,000 is good, whence it is possible to use the computation to obtain integrated force data unavailable in the experiment. These were studied for Re= 100 and 1000. Lift prediction from the computation shows a direct proportionality of lift to the pitch rate on the pitch upstroke. Finally, we compare pitch vs. plunge, and find that quasi-steady prediction is reasonably successful in predicting a combined pitch-plunge that effectively cancels the leading edge vortex, but not in canceling the trailing vortex system.
Innovations in University Education in Innovation: Moving Beyond the B.S.
Authors: Boult T. , Chamillard A. , Lewis R. , Polok N. , Stock G. , Wortman D.
Published: March 2010

This article focuses on university education in innovation. We examine and present a novel system we have developed that is achieving our vision of instantiating a robust education that teaches, develops, and grades innovation in the education system. This paper is discussing a paradigm shift, offering new degrees with a common core focused on innovation, with teams of students learning and practicing the key elements of the innovation process. First we examine the motivation and need for a radically new approach, not a new major or a course, that is based upon a new common core and family of degrees. We describe how we knew that to effectively reach our goals the program had to span across departments, college boundaries, and beyond the very core of the university. Second, we show how in doing so we created a family of degrees that moved us beyond the centuries-old B.S. and B.A. educational constraints with a new, innovative "Bachelor of Innovation™" (B.I.) family of degrees that includes a core built around multi-disciplinary multi-year innovation partnering with real companies. Lastly we summarize the unique aspects of the program and the rationale behind them, from the 3-year multi-disciplinary team experience to the trademarked name. We present our B.I. program as its own case study in innovation within higher education, reviewing the key challenges we faced so that other innovative institutions and departments may learn from our experience. We conclude with lessons learned and the future of the B.I. family of degrees.
Modeling Bubble Flow and Current Density Distribution in an Alkaline Electrolysis Cell
Authors: Jupudi Ravichandra S. , Zhang Hongmei , Zappi Guillermo , Bourgeois Richard
Published: March 2010

The effect of bubbles on the current density distribution over the electrodes of an alkaline electrolyzer cell is studied using a two-dimensional computational fluid dynamics model. Model includes Eulerian-Eulerian two-phase flow methodology to model the multiphase flow of Hydrogen and Oxygen with water and the behavior of each phase is accounted for using first principle. Hydrogen/Oxygen evolution, flow field and current density distribution are incorporated in the model to account for the complicated physics involved in the process. Fluent 6.2 is used to solve two-phase flow and electrochemistry is incorporated using UDF (User Defined Function) feature of Fluent. Model is validated with mesh refinement study and by comparison with experimental measurements. Model is found to replicate the effect of cell voltage and inter-electrode gap (distance between the electrodes) on current density accurately. Further, model is found to capture the existence of optimum cell height. The validated model is expected to be a very useful tool in the design and optimization of alkaline electrolyzer cells.
Interfacial Area Transport Equations for Gas-Liquid Flow
Authors: Hibiki Takashi , Ishii Mamoru
Published: March 2010

In relation to the modeling of the interfacial transfer terms in the two-fluid model, the concept of the interfacial area transport equation has been proposed to develop a constitutive relation for the interfacial area concentration. The interfacial area transport equation can replace the traditional flow regime maps and regime transition criteria. The changes in the two-phase flow structure can be predicted mechanistically and the effects of the boundary conditions and flow development are efficiently modeled by this transport equation. A successful development of the interfacial area transport equation can make a significant improvement in the two-fluid model formulation and the prediction accuracy of three-dimensional two-phase flow simulations. In this paper, the basic concept of the interfacial area transport equation and its formulation have been briefly described. Available models of the interfacial area sink and source terms and existing databases have been reviewed and the interfacial area transport equation has been benchmarked using adiabatic bubbly flow and condensation bubbly flow data. Future direction for this research has been suggested.
Two-Fluid Models for Simulating Dispersed Multiphase Flows-A Review
Authors: Zhou L.X.
Published: March 2010

The development of two-fluid models for simulating dispersed multiphase flows (gas-particle, gas-droplet, bubble-liquid, liquid-particle flows) by the present author within the last 20 years is systematically reviewed. The two-fluid models based on Reynolds expansion, time averaging and mass-weighed averaging, and also PDF transport equations are described. Different versions of two-phase turbulence models, including the unified second-order moment (USM) and k-ε-kp models, the DSM-PDF model, the SOM-MC model, the nonlinear k-e-kp model, and the USM-Θ model for dense gas-particle flows and their application and experimental validation are discussed.
Multi-Size Particulate Flow through Rotating Channel — Modeling and Validation Using Three Turbulence Models
Authors: Gupta Pankaj K. , Pagalthivarthi Krishnan V.
Published: March 2010

A comparison of three turbulence models in modeling and validating dense multi-size particulate flow through rotating channel is presented. All the three turbulence models incoporate a rotation modification to the production term in the turbulent kinetic energy equation. In the first model, rotation-modified k – ε equations are used to compute the eddy viscosity of pure carrier which is then modified for the presence of particles. In the other two models, rotation-modified km – εm equations are solved for the mixture directly. The eddy viscosities are then computed from km and εm. The predicted results of all three models show excellent mesh independence. The coarsest mesh satisfied the mass conservation to within 0.1%. The code based on pure carrier-phase eddy viscosity (modified for concentration) is computationally 2–3 times more efficient than the other two (mixture-based) models. The predicted results using all three turbulence models are compared against applicable experimental results in the open literature. Regression between the computed and experimental results shows excellent agreement between the two.
A Review of Population Balance Modelling for Isothermal Bubbly Flows
Authors: Cheung Sherman C.P. , Yeoh Guan Heng , Tu Jiyuan
Published: March 2010

In this article, we present a review of the state-of-the-art population balance modelling techniques that have been adopted to describe the phenomenological nature of isothermal bubbly flows. The main focus of the review can be broadly classified into three categories: (i) Numerical approaches or solution algorithms of the PBE; (ii) Applications of the PBE in practical gas-liquid multiphase problems and (iii) Possible aspects of the future development in population balance modelling. For the first category, details of solution algorithms based on both method of moment (MOM) and discrete class method (CM) that have been proposed in the literature are provided. Advantages and drawbacks of both approaches are also discussed from the theoretical and practical viewpoints. For the second category, applications of existing population balance models in practical multiphase problems that have been proposed in the literature are summarized. Selected existing mathematical closures for modelling the “birth” and “death” rate of bubbles in gas-liquid bubbly flows are introduced. Particular attention is devoted to assess the capability of some selected models in predicting bubbly flow conditions through detail validation studies against experimental data. These studies demonstrate that good agreement can be achieved by the present model by comparing the predicted results against measured data with regards to the radial distribution of void fraction and sauter mean bubble diameter. Finally, weaknesses and limitations of the existing models are revealed are suggestions for further development are discussed. Emerging topics for future population balance studies are provided as to complete the aspect of population balance modelling.
Assessment of Interface Capturing Methods in Computational Fluid Dynamics (CFD) Codes — A Case Study
Authors: Yeoh Guan Heng , Barber Tracie
Published: March 2010

This paper reports on an exemplary study of the performance of Computational Fluid Dynamics (CFD) computer codes for the case study of interfacial flows including surface tension. The finite volume codes of ANSYS, Inc., Fluent and CFX have been evaluated by performing CFD-simulations of collapsing water columns with and without an obstacle within enclosures. In both of these computer codes, the interfaces are treated by the volume of fluid method. The main difference is attributed to the absence of any surface reconstruction algorithms in ANSYS, Inc., CFX. Rather, the so-called “compressive scheme” is applied instead to overcome numerical diffusion and smearing of the interface. ANSYS, Inc., Fluent, however, employs the geometric reconstruction algorithm based on the Piecewise Linear Interface Construction (PLIC) method. The study assesses the simulation results obtained through the two computer codes by comparing against experimental observations and measurements as well as numerical predictions from other CFD codes if available.
Detection of Pathological Myopia by PAMELA with Texture‐Based Features through an SVM Approach
Authors: Liu Jiang , Wong Damon W. K. , Lim Joo Hwee , Tan Ngan Meng , Zhang Zhuo , Li Huiqi , Yin Fengshou , Lee Benghai , Saw Seang Mei , Tong Louis , Wong Tien Yin
Published: March 2010

Pathological myopia is the seventh leading cause of blindness worldwide. Current methods for the detection of pathological myopia are manual and subjective. We have developed a system known as PAMELA (Pathological Myopia Detection Through Peripapillary Atrophy) to automatically assess a retinal fundus image for pathological myopia. This paper focuses on the texture analysis component of PAMELA which uses texture features, clinical image context and support vector machine‐based classification to detect the presence of pathological myopia in a retinal fundus image. Results on a test image set from the Singapore Eye Research Institute show an accuracy of 87.5% and a sensitivity and specificity of 0.85 and 0.90 respectively. The results show good promise for PAMELA to be developed as an automatic tool for pathological myopia detection.
Semi‐Automatic Anatomical Tree Matching for Landmark‐Based Elastic Registration of Liver Volumes
Authors: Drechsler Klaus , Laura Cristina , Chen Yufei , Erdt Marius
Published: March 2010

One promising approach to register liver volume acquisitions is based on the branching points of the vessel trees as anatomical landmarks inherently available in the liver. Automated tree matching algorithms were proposed to automatically find pair‐wise correspondences between two vessel trees. However, to the best of our knowledge, none of the existing automatic methods are completely error free. After a review of current literature and methodologies on the topic, we propose an efficient interaction method that can be employed to support tree matching algorithms with important pre‐selected correspondences or after an automatic matching to manually correct wrongly matched nodes. We used this method in combination with a promising automatic tree matching algorithm also presented in this work. The proposed method was evaluated by 4 participants and a CT dataset that we used to derive multiple artificial datasets.
Water-Uptake Capacity of Bentonites
Authors: Kaufhold S. , Dohrmann R. , Klinkenberg M.
Published: March 2010

The present study compares the water-vapor adsorption capacity of bentonites (natural cation population) with the Enslin-Neff method. Water-vapor adsorption at 50% r.h. (relative humidity) or 70% r.h. is known to depend heavily on the amount of permanent charge and on the type of exchangeable cation. At ~80% r.h. Na+- and Ca2+/Mg2+-dominated bentonites take up equal amounts of water. Comparing the water-uptake capacity at 80% r.h. with the cation exchange capacity (CEC) revealed a close correlation between these two variables. Appreciable scatter apparent from this plot, however, suggests that additional factors influence the water-uptake capacity.Water adsorption at external surfaces was considered to be one of these factors and was, in fact, implicated by N2-adsorption data. The ratio of external/internal water ranged from 0 to 1, which suggests that water-adsorption values cannot be applied in the calculation of the internal surface area without correction for external water.

The Enslin-Neff water-uptake capacity, on the other hand, is unaffected by microstructural features (e.g. specific surface area and porosity). The amount of exchangeable Na+ is themost important factor. However, the relationship between the Na+ content and the Enslin value is not linear but may be explained by percolation theory.
Stacking Disorder in a Sedimentary Kaolinite
Authors: Kogure Toshihiro , Elzea-Kogel Jessica , Johnston Cliff T. , Bish David L.
Published: March 2010

Although structural disorder in kaolinite has been investigated extensively, it is still not understood properly. To investigate the problem, a kaolinite specimen of sedimentary origin from Capim, Brazil, was examined, mainly by transmission electron microscopy (TEM). Selected-area electron diffraction (SAED) along the Xi ([100], [110], and []) directions shows various features, from completely discrete patterns to heavily streaked ones along the c* direction, suggesting that the degree of stacking disorder is variable among individual grains. High-resolution TEM images indicate that stacking faults are mainly caused by disorder of alternating t1 (~ −a/3) and t2 (−a/3 +b/3) layer displacements. Furthermore, stacking faults have been observed (1) as isolated stacking faults (e.g. insertion of an isolated t2 `fault' in an ordered sequence with t1 layer displacement) and (2) as interstratification of two kinds of multilayer blocks having regular t1 and t2 layer displacements. A mixture of grains with various degrees and modes of disorder with alternating t1 and t2 layer displacements may explain the experimental profile of the 02, 11 X-ray diffraction band.

Faults related to displacement of the octahedral vacancy and/or to layer rotation were also observed in HRTEM images. The SAED patterns along the Yi ([010], [310], and []) directions occasionally have extra spots and/or streaks, suggesting the presence of stacking sequences with (±60°, 180°) mutual layer rotation and/or with (0, ±b/3) layer displacements. The local dickite or nacrite-like fragments formed by these faults are in qualitative agreement with recent low-temperature FTIR results from this sample, where distinct ν(OH) absorption bands reflect multiple interlayer O-H⋯O environments that are possibly ascribed to dickite and nacrite.