Sample records for flow activation energy

  1. Surface diffusion and flow activation energies of perfluoropolyalkylether

    Microsoft Academic Search

    Teresa M. O'Connor; Myung S. Jhon; Charles L. Bauer; Byung G. Min; Do Y. Yoon; Thomas E. Karis

    1995-01-01

    Surface diffusion of perfluoropolyalkylether (PFPE) Fomblin Z15 and Fomblin Zdol (hydroxyl terminated PFPE) on silicon wafers was investigated over the temperature range of 25 to 50°C using scanning microellipsometry. Zdol exhibits a much lower mobility and a distinctly different thickness profile as compared to Z15. The activation energy for surface diffusion of Zdol is higher than that of Z15, reflecting

  2. Energy Flow

    NSDL National Science Digital Library

    The representation depicts the transfer of energy in a food chain. The resource is an interactive illustration of a farm scene depicting the flow of energy between the sun, a cornfield, a cow and a human through a food chain. To view the illustration, select Continue, then select Energy Flow button.

  3. Determination of the Arrhenius Activation Energy Using a Temperature-Programmed Flow Reactor.

    ERIC Educational Resources Information Center

    Chan, Kit-ha C.; Tse, R. S.

    1984-01-01

    Describes a novel method for the determination of the Arrhenius activation energy, without prejudging the validity of the Arrhenius equation or the concept of activation energy. The method involves use of a temperature-programed flow reactor connected to a concentration detector. (JN)

  4. Activation energy for superplastic flow in aluminum matrix composites exhibiting high-strain-rate superplasticity

    Microsoft Academic Search

    M. Mabuchi; K. Higashi

    1996-01-01

    The activation energy for superplastic flow in a variety of Si3N4Al composites exhibiting high-strain-rate superplasticity was analyzed. The activation energy in a solid state including no liquid was in agreement with the one for lattice self-diffusion. However, the activation energy was increased by the presence of a liquid phase. The behaviors of the Al-Cu-Mg(2124) alloy composites were different from those

  5. Active flow control integrated diffuser (afcid) for increased energy efficiency in variable air volume systems

    NASA Astrophysics Data System (ADS)

    Van Der Schijff, Hermanus P.

    Variable air volume (VAV) air terminals are designed to save energy by reducing airflow into a given space based on occupancy and required load. Systems are typically designed to operate at peak load, however as load is reduced, performance is compromised due to inadequate throw. As a result, fans are installed to adjust for the losses, negating many of the energy savings. Additionally flow is vectored by the use of vanes, a basic passive type of flow control. An experimental investigation was performed to study the application of flow control on that of a HVAC diffuser using synthetic jets distributed evenly along the diffuser edge parallel to the flow field. The study was conducted on a 1:3 scale typical office space (150 ft2), which included a simulated scale HVAC system supplied by compressed air. Two different jet blowing ratios were investigated for system loads of 60% and 90%. The flow field was established using hot wire anemometry and Particle Image Velocimetry (PIV). This study demonstrates the effectiveness of synthetic jet based active flow control at controlling airflow, showing ability to affect throw parameters for changing flow rates within the test chamber. Vectoring of up to 20% and improvement in jet spread of 200% was demonstrated. The use of such devices has the potential to improve air quality and air distribution in building while simultaneously lowering energy demands of HVAC systems.

  6. Active Lava Flow

    USGS Multimedia Gallery

    Flows continue to be active south of the Kalapana access road, heading in a generally eastward direction. These breakouts were active just a few hundred meters east of the County lava viewing area....

  7. On the possibility of estimating weak interactions of macromolecules in solutions from the experimental viscous flow activation energies data

    Microsoft Academic Search

    E. P. Varfolomeeva; V. Ya. Grinberg; V. B. Tolstogusov

    1980-01-01

    The initial viscosity and activation energy in viscous flow of the systems: water(W)-casein(C)-polysaccharide(PS) (gum arabic(G),de-xtran(D), extran sulfat (DS)) have been determined for various ionic strengths corresponding to total or limited thermodynamic compatibility of macrocomponents. Excess activation energy ?H?E due to the protein-polysaccharide interactions has been calculated. It is positive for systems with total compatibility and negative for systems with limited

  8. Productivity & Energy Flow

    E-print Network

    Mitchell, Randall J.

    1 Productivity & Energy Flow Ecosystem approach, focuses: on flow of energy, water, and nutrients (capture) of energy by autotrophs Gross (total) Net (total ­ costs) Secondary productivity- capture of energy by herbivores http://sciencebitz.com/?page_id=204 What Controls the Primary Productivity

  9. Active Flow Control Integrated Diffuser for increased Energy Efficiency in Variable Air Volume Systems

    NASA Astrophysics Data System (ADS)

    van der Schijff, Hermanus; Menicovich, David; Vollen, Jason; Amitay, Michael

    2013-11-01

    An experimental investigation was performed to study the application of flow control on an HVAC diffuser using synthetic jets distributed evenly along the diffuser edges. The study was conducted on 1:3 scale typical office space (150 ft2) , which included a simulated scale HVAC system supplied by compressed air. Two different jet momentum coefficients were investigated for two inlet flow rates of 40 and 60 CFM. The flow field was measured using hot wire anemometry and Particle Image Velocimetry. Current Variable Air Volume HVAC systems vary the incoming airflow to adjust to changing temperature conditions in the conditioned space. However, when the air flow rate drops below ideal, air distribution becomes inefficient. This study demonstrates the effectiveness of synthetic jets at controlling the incoming airflow and the distribution in the room, showing ability to affect throw coefficient parameters for different flow rates within the test chamber. The use of such devices has the potential to improve air quality and air distribution in building while simultaneously lowering energy demands of HVAC systems.

  10. Activation energy for mobility of dyes and proteins in polymer solutions: from diffusion of single particles to macroscale flow.

    PubMed

    Soza?ski, Krzysztof; Wi?niewska, Agnieszka; Kalwarczyk, Tomasz; Ho?yst, Robert

    2013-11-27

    We measure the activation energy Ea for the diffusion of molecular probes (dyes and proteins of radii from 0.52 to 6.9 nm) and for macroscopic flow in a model complex liquid-aqueous solutions of polyethylene glycol. We cover a broad range of polymer molecular weights, concentrations, and temperatures. Fluorescence correlation spectroscopy and rheometry experiments reveal a relationship between the excess of the activation energy in polymer solutions over the one in pure solvent ?Ea and simple parameters describing the structure of the system: probe radius, polymer hydrodynamic radius, and correlation length. ?Ea varies by more than an order of magnitude in the investigated systems (in the range of ca. 1-15 kJ/mol) and for probes significantly larger than the polymer hydrodynamic radius approaches the value measured for macroscopic flow. We develop an explicit formula describing the smooth transition of ?Ea from the diffusion of molecular probes to macroscopic flow. This formula is a reference for the quantitative analysis of specific interactions of moving nano-objects with their environment as well as active transport. For instance, the power developed by a molecular motor moving at constant velocity u is proportional to u2exp(Ea/RT). PMID:24329475

  11. Activation Energy for Mobility of Dyes and Proteins in Polymer Solutions: From Diffusion of Single Particles to Macroscale Flow

    NASA Astrophysics Data System (ADS)

    Soza?ski, Krzysztof; Wi?niewska, Agnieszka; Kalwarczyk, Tomasz; Ho?yst, Robert

    2013-11-01

    We measure the activation energy Ea for the diffusion of molecular probes (dyes and proteins of radii from 0.52 to 6.9 nm) and for macroscopic flow in a model complex liquid—aqueous solutions of polyethylene glycol. We cover a broad range of polymer molecular weights, concentrations, and temperatures. Fluorescence correlation spectroscopy and rheometry experiments reveal a relationship between the excess of the activation energy in polymer solutions over the one in pure solvent ?Ea and simple parameters describing the structure of the system: probe radius, polymer hydrodynamic radius, and correlation length. ?Ea varies by more than an order of magnitude in the investigated systems (in the range of ca. 1-15kJ/mol) and for probes significantly larger than the polymer hydrodynamic radius approaches the value measured for macroscopic flow. We develop an explicit formula describing the smooth transition of ?Ea from the diffusion of molecular probes to macroscopic flow. This formula is a reference for the quantitative analysis of specific interactions of moving nano-objects with their environment as well as active transport. For instance, the power developed by a molecular motor moving at constant velocity u is proportional to u2exp?(Ea/RT).

  12. US energy flow, 1991

    SciTech Connect

    Borg, I.Y.; Briggs, C.K.

    1992-06-01

    Trends in energy consumption and assessment of energy sources are discussed. Specific topics discussed include: energy flow charts; comparison of energy use with 1990 and earlier years; supply and demand of fossil fuels (oils, natural gas, coal); electrical supply and demand; and nuclear power.

  13. NEED Project: Energy Flows

    NSDL National Science Digital Library

    This teaching module for Grades 6-8 introduces energy transfers and transformations and the flow of energy through systems. The core of the lesson is its 14 custom graphics developed by the NEED project to show energy flow in real-life systems, from start to finish. The graphics (much easier to digest than Sankey diagrams) were designed to help students understand that energy can be transferred and converted into other forms, but never destroyed. It includes a unique "Energy Flow Card" game, where students engage in creative dramatics to act out energy transformations by connecting the cards correctly. The NEED Project is a national initiative to bring innovative curriculum materials in energy education to teachers and learners from the primary grades through college.

  14. Food Web and Energy Flow

    NSDL National Science Digital Library

    Janet R. Galle

    2005-01-01

    This chapter discusses the concept of a food web and energy flow. Its activities will assist students in defining and constructing an energy pyramid. These activities can be incorporated into lessons which teach students how to create a food web and and identify the interdependencies within that habitat. Students will learn how to identify and illustrate parts of the water cycle, the carbon-oxygen cycle, and the nitrogen cycle. This section also offers students the tools to demonstrate active knowledge of conservation measures.

  15. The Flow of Energy

    Microsoft Academic Search

    F. Znidarsic; G. A. Robertson

    2011-01-01

    In this paper, the flow of energy in materials is presented as mechanical waves with a distinct velocity or speed of transition. This speed of transition came about through the observations of cold fusion experiments, i.e., Low Energy Nuclear Reactions (LENR) and superconductor gravity experiments, both assumed speculative by mainstream science. In consideration of superconductor junctions, the LENR experiments have

  16. Energy Flow Energy Flow Energy Flow A.Ukleja, T.Tymieniecka, I.Skillicorn 1 Azimuthal asymmetry

    E-print Network

    Energy Flow Energy Flow Energy Flow A.Ukleja, T.Tymieniecka, I.Skillicorn 1 Azimuthal asymmetry using energy flow method Azimuthal angle distribution at Q2 >100 GeV2 Energy flow method.Ukleja on behalf of the ZEUS Collaboration #12; Energy Flow Energy Flow Energy Flow A.Ukleja, T.Tymieniecka, I

  17. The Flow of Energy

    NASA Astrophysics Data System (ADS)

    Znidarsic, F.; Robertson, G. A.

    In this paper, the flow of energy in materials is presented as mechanical waves with a distinct velocity or speed of transition. This speed of transition came about through the observations of cold fusion experiments, i.e., Low Energy Nuclear Reactions (LENR) and superconductor gravity experiments, both assumed speculative by mainstream science. In consideration of superconductor junctions, the LENR experiments have a similar speed of transition, which seems to imply that the reactions in the LENR experiment are discrete quantized reactions (energy - burst vs. continuous). Here an attempt is made to quantify this new condition as it applies to electrons; toward the progression of quantized energy flows (discrete energy burst) as a new source of clean energy and force mechanisms (i.e, propulsion).

  18. Radiant Energy Flow

    NSDL National Science Digital Library

    The Concord Consortium

    2011-12-11

    How does energy flow in and out of our atmosphere? Explore how solar and infrared radiation enters and exits the atmosphere with an interactive model. Control the amounts of carbon dioxide and clouds present in the model and learn how these factors can influence global temperature. Record results using snapshots of the model in the virtual lab notebook where you can annotate your observations.

  19. Correlation between viscous-flow activation energy and phase diagram in four systems of Cu-based alloys

    Microsoft Academic Search

    Shuang Ning; Xiufang Bian; Zhenfeng Ren

    2010-01-01

    Activation energy is obtained from temperature dependence of viscosities by means of a fitting to the Arrhenius equation for liquid alloys of Cu–Sb, Cu–Te, Cu–Sn and Cu–Ag systems. We found that the changing trend of activation energy curves with concentration is similar to that of liquidus in the phase diagrams. Moreover, a maximum value of activation energy is in the

  20. Actuators for Active Flow Control

    NASA Astrophysics Data System (ADS)

    Cattafesta, Louis N., III; Sheplak, Mark

    2011-01-01

    Actuators are transducers that convert an electrical signal to a desired physical quantity. Active flow control actuators modify a flow by providing an electronically controllable disturbance. The field of active flow control has witnessed explosive growth in the variety of actuators, which is a testament to both the importance and challenges associated with actuator design. This review provides a framework for the discussion of actuator specifications, characteristics, selection, design, and classification for aeronautical applications. Actuator fundamentals are discussed, and various popular actuator types used in low-to-moderate speed flows are then described, including fluidic, moving object/surface, and plasma actuators. We attempt to highlight the strengths and inevitable drawbacks of each and highlight potential future research directions.

  1. A Critical Review of Thermodiffusion Models: Role and Significance of the Heat of Transport and the Activation Energy of Viscous Flow

    NASA Astrophysics Data System (ADS)

    Eslamian, Morteza; Saghir, M. Ziad

    2009-06-01

    In this paper thermodiffusion models developed to estimate the thermal diffusion factor in nonideal liquid mixtures are reviewed; the merits and shortcomings of each model are discussed in detail. Most of these models are multicomponent in principle; however our focus here is on binary mixtures. Two rather different groups of models are identified: models needing a matching parameter to be obtained usually from the outside of thermodynamics, and the self-contained or independent models. Derivation of the matching parameter models using linear non-equilibrium thermodynamics and the details of how to find the matching parameters are investigated. The physical meaning of parameters such as the net heat of transport and the activation energy of viscous flow is elucidated, as the literature is overwhelmed with confusing and misleading information. The so-called dynamic and static models and their relations to the matching and non-matching parameter models are also discussed. We conclude that modeling the net heat of transport by the activation energy of self-diffusion may provide better results than approximating it by the activation energy of viscous flow. Nonetheless, the matching parameter models, which use the activation energy of viscous flow, are more dynamic and predict the thermal diffusion factor better than the non-matching parameter or static models, such as those of Kempers and Haase.

  2. Boeing active flow control system

    NASA Astrophysics Data System (ADS)

    Jacot, A. Dean; Calkins, Frederick T.

    2000-06-01

    The Boeing Active Flow Control (AFC) System (BAFCS) is a DARPA sponsored program to develop AFC technology to achieve a significant increase in payload for the V-22 tiltrotor vehicle. The program includes Computational Fluid Dynamics analysis, wind tunnel testing and development of smart materials based AFC actuators. This paper will provide an overview of the program and its interrelationships, as well as concentrating on the development of the AFC actuators.

  3. 2007 Estimated International Energy Flows

    SciTech Connect

    Smith, C A; Belles, R D; Simon, A J

    2011-03-10

    An energy flow chart or 'atlas' for 136 countries has been constructed from data maintained by the International Energy Agency (IEA) and estimates of energy use patterns for the year 2007. Approximately 490 exajoules (460 quadrillion BTU) of primary energy are used in aggregate by these countries each year. While the basic structure of the energy system is consistent from country to country, patterns of resource use and consumption vary. Energy can be visualized as it flows from resources (i.e. coal, petroleum, natural gas) through transformations such as electricity generation to end uses (i.e. residential, commercial, industrial, transportation). These flow patterns are visualized in this atlas of 136 country-level energy flow charts.

  4. Energy flow or Particle flow The technique of "energy flow" for pedestrians.

    E-print Network

    Boyer, Edmond

    and the other to a muon pair. But most often hadronic jets with rather low energy tracks populate the detector it makes the low energy tracks curl around to end up in the end caps. This is even clearer in the figure 6Energy flow or Particle flow The technique of "energy flow" for pedestrians. Henri Videau LLR

  5. Visible and Thermal Images: Active Flows

    USGS Multimedia Gallery

    Flows continue to be active on the pali and are advancing southward. The flow front this morning was approximately 1.4 km (0.9 miles) north of the County viewing area. Letters A and B denote corresponding points in the photograph (top) and thermal image (bottom). The active flows show up clearly in ...

  6. Gradient Vector Flow Fast Geometric Active Contours

    E-print Network

    Paragios, Nikos

    Gradient Vector Flow Fast Geometric Active Contours Nikos Paragios, Olivier Mellina-Gottardo, and Visvanathan Ramesh Abstract--In this paper, we propose an edge-driven bidirectional geometric flow for boundary extraction. To this end, we combine the geodesic active contour flow [3] and the gradient vector

  7. Transverse Energy Flow at HERA

    E-print Network

    K. Golec-Biernat; J. Kwiecinski; A. D. Martin; P. J. Sutton

    1994-05-27

    We calculate the transverse energy flow accompanying small $x$ deep-inelastic events and compare with recent data obtained at HERA. In the central region between the current jet and the remnants of the proton we find that BFKL leading $\\ln(1/x)$ dynamics gives a distinctively large transverse energy distribution, in approximate agreement with recent data.

  8. Carbon Energy Flows Belowground

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants use photosynthesis to convert carbon dioxide in the atmosphere and energy from sunlight into energy-containing, carbon-based foodstuffs (i.e. carbohydrates such as sugars and starches) that provide the building blocks for all life on Earth. Without photosynthesis, sunlight would not be a goo...

  9. US energy flow, 1990

    SciTech Connect

    Borg, I.Y.; Briggs, C.K.

    1991-06-01

    Energy consumption in the US changed only slightly in 1990. Transportation used was close to 1988 and 1989 levels. Improvements in automobile efficiency were compensated by an increase in the number of miles driven. A larger energy use in the industrial sector was offset by decreases in the residential/commercial sector. Energy use in the latter sector was influenced by a relatively mild, nation-wide summer and winter. All end-use sectors were affected by the high fuel prices related to the Kuwait-Iraq war in the last half of the year and by an attendant economic downturn. Electrical use rose slightly and thus deviated from the 3-4% annual increases recorded in the previous decade. Nuclear energy's contribution to electrical generation increased to almost 21%, and capacity factors reached 66%, an all time high in the US. Renewable sources of energy apart from hydroelectric power showed negligible growth. Domestic natural gas and coal production rose, and oil production continued its steady decline. As oil constitutes 41% of US energy consumption, failing domestic production has been augmented by imports. Collectively energy imports constituted two-thirds of the US trade deficit in 1990. The ratio between energy consumption and GNP declined slightly in 1990 as it has for almost every year since 1972. The Services'' component of the GNP increased in 1990 and the Goods'' and Structures'' components declined in keeping with an even longer trend. 29 refs., 7 figs., 4 tabs.

  10. Composite Photo of Active Flow Front

    USGS Multimedia Gallery

    This composite image combines a thermal image with a normal photograph, and shows the active flow front in Kalapana. The flow is abutting the raised ground of the Hakuma horst, which is diverting the flows to the east and bringing them closer to residences....

  11. Visual tracking, active vision, and gradient flows

    Microsoft Academic Search

    Allen Tannenbaum; Anthony Yezzi

    In this note, we discuss the minimization of certain functionals and the resulting gradient flows for problems in active vision.\\u000a In particular, we consider how these techniques may be applied to deformable contours, and L\\u000a 1-based methods for optical flow. Such techniques are becoming essential tools in the emerging field of controlled active vision.

  12. Thermal and Visible Imagery: Active Flows

    USGS Multimedia Gallery

    This comparison of thermal images over the coastal plain shows the advancement of the active flows over the past week. At the top, a normal photograph from April 15 gives reference. The middle frame, from April 15, shows that the flows were approaching the bottom of the pali last week. In the bottom...

  13. Terrestrial Photogrammetry of Active Lava Flows

    Microsoft Academic Search

    M. James; S. Robson

    2006-01-01

    In order to improve our understanding of how lavas flow, cool and stop, accurate and frequent DEMs and associated temperature measurements of active flows are required. We describe the use of terrestrial photogrammetric techniques which allow detailed measurements to be carried out rapidly, frequently and over relevant spatial scales. Furthermore, the equipment required is sufficiently small and light to be

  14. Energy Flow in the Atmosphere

    NSDL National Science Digital Library

    2012-08-03

    This textbook chapter introduces the concepts of static and dynamic equilibrium, and discusses contemporary climate change. The greenhouse effect is presented in a discussion of Mars, Venus and Earth, the "Goldilocks" planet. Two investigations support the chapter. The resource includes links to current news articles, and a suite of pre- and post-unit assessments. A teacher's guide supports classroom use. This is the sixth chapter in the unit, Energy Flow, exploring the flow of energy through the atmosphere, oceans, land, and living things over short and long timescales. The resource is part of Global System Science (GSS), an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact.

  15. Energy and material flows of megacities.

    PubMed

    Kennedy, Christopher A; Stewart, Iain; Facchini, Angelo; Cersosimo, Igor; Mele, Renata; Chen, Bin; Uda, Mariko; Kansal, Arun; Chiu, Anthony; Kim, Kwi-Gon; Dubeux, Carolina; Lebre La Rovere, Emilio; Cunha, Bruno; Pincetl, Stephanie; Keirstead, James; Barles, Sabine; Pusaka, Semerdanta; Gunawan, Juniati; Adegbile, Michael; Nazariha, Mehrdad; Hoque, Shamsul; Marcotullio, Peter J; González Otharán, Florencia; Genena, Tarek; Ibrahim, Nadine; Farooqui, Rizwan; Cervantes, Gemma; Sahin, Ahmet Duran

    2015-05-12

    Understanding the drivers of energy and material flows of cities is important for addressing global environmental challenges. Accessing, sharing, and managing energy and material resources is particularly critical for megacities, which face enormous social stresses because of their sheer size and complexity. Here we quantify the energy and material flows through the world's 27 megacities with populations greater than 10 million people as of 2010. Collectively the resource flows through megacities are largely consistent with scaling laws established in the emerging science of cities. Correlations are established for electricity consumption, heating and industrial fuel use, ground transportation energy use, water consumption, waste generation, and steel production in terms of heating-degree-days, urban form, economic activity, and population growth. The results help identify megacities exhibiting high and low levels of consumption and those making efficient use of resources. The correlation between per capita electricity use and urbanized area per capita is shown to be a consequence of gross building floor area per capita, which is found to increase for lower-density cities. Many of the megacities are growing rapidly in population but are growing even faster in terms of gross domestic product (GDP) and energy use. In the decade from 2001-2011, electricity use and ground transportation fuel use in megacities grew at approximately half the rate of GDP growth. PMID:25918371

  16. Analysis of Flow Cytometry DNA Damage Response Protein Activation Kinetics Following X-rays and High Energy Iron Nuclei Exposure

    SciTech Connect

    Universities Space Research Association; Chappell, Lori J.; Whalen, Mary K.; Gurai, Sheena; Ponomarev, Artem; Cucinotta, Francis A.; Pluth, Janice M.

    2010-12-15

    We developed a mathematical method to analyze flow cytometry data to describe the kinetics of {gamma}H2AX and pATF2 phosphorylations ensuing various qualities of low dose radiation in normal human fibroblast cells. Previously reported flow cytometry kinetic results for these DSB repair phospho-proteins revealed that distributions of intensity were highly skewed, severely limiting the detection of differences in the very low dose range. Distributional analysis reveals significant differences between control and low dose samples when distributions are compared using the Kolmogorov-Smirnov test. Radiation quality differences are found in the distribution shapes and when a nonlinear model is used to relate dose and time to the decay of the mean ratio of phosphoprotein intensities of irradiated samples to controls. We analyzed cell cycle phase and radiation quality dependent characteristic repair times and residual phospho-protein levels with these methods. Characteristic repair times for {gamma}H2AX were higher following Fe nuclei as compared to X-rays in G1 cells (4.5 {+-} 0.46 h vs 3.26 {+-} 0.76 h, respectively), and in S/G2 cells (5.51 {+-} 2.94 h vs 2.87 {+-} 0.45 h, respectively). The RBE in G1 cells for Fe nuclei relative to X-rays for {gamma}H2AX was 2.05 {+-} 0.61 and 5.02 {+-} 3.47, at 2 h and 24-h postirradiation, respectively. For pATF2, a saturation effect is observed with reduced expression at high doses, especially for Fe nuclei, with much slower characteristic repair times (>7 h) compared to X-rays. RBEs for pATF2 were 0.66 {+-} 0.13 and 1.66 {+-} 0.46 at 2 h and 24 h, respectively. Significant differences in {gamma}H2AX and pATF2 levels comparing irradiated samples to control were noted even at the lowest dose analyzed (0.05 Gy) using these methods of analysis. These results reveal that mathematical models can be applied to flow cytometry data to uncover important and subtle differences following exposure to various qualities of low dose radiation.

  17. Acoustic energy in non-uniform flows

    Microsoft Academic Search

    C. L. Morfey

    1971-01-01

    The concept of acoustic energy is extended to non-uniform fluid flows. In general, the resulting energy balance equation exhibits acoustic energy production or dissipation within the flow, but in an important special case the production term is zero, implying conservation of acoustic energy. The acoustic energy equations used in classical and geometric acoustics are recovered from the general formulation by

  18. Go with the Energy Flow

    NSDL National Science Digital Library

    2014-09-18

    Students learn about energy and nutrient flow in various biosphere climates and environments. They learn about herbivores, carnivores, omnivores, food chains and food webs, seeing the interdependence between producers, consumers and decomposers. Students are introduced to the roles of the hydrologic (water), carbon, and nitrogen cycles in sustaining the worlds' ecosystems so living organisms survive. This lesson is part of a series of six lessons in which students use their growing understanding of various environments and the engineering design process, to design and create their own model biodome ecosystems.

  19. Observing and Modeling Earth's Energy Flows

    NASA Astrophysics Data System (ADS)

    Stevens, Bjorn; Schwartz, Stephen E.

    2012-07-01

    This article reviews, from the authors' perspective, progress in observing and modeling energy flows in Earth's climate system. Emphasis is placed on the state of understanding of Earth's energy flows and their susceptibility to perturbations, with particular emphasis on the roles of clouds and aerosols. More accurate measurements of the total solar irradiance and the rate of change of ocean enthalpy help constrain individual components of the energy budget at the top of the atmosphere to within ±2 W m-2. The measurements demonstrate that Earth reflects substantially less solar radiation and emits more terrestrial radiation than was believed even a decade ago. Active remote sensing is helping to constrain the surface energy budget, but new estimates of downwelling surface irradiance that benefit from such methods are proving difficult to reconcile with existing precipitation climatologies. Overall, the energy budget at the surface is much more uncertain than at the top of the atmosphere. A decade of high-precision measurements of the energy budget at the top of the atmosphere is providing new opportunities to track Earth's energy flows on timescales ranging from days to years, and at very high spatial resolution. The measurements show that the principal limitation in the estimate of secular trends now lies in the natural variability of the Earth system itself. The forcing-feedback-response framework, which has developed to understand how changes in Earth's energy flows affect surface temperature, is reviewed in light of recent work that shows fast responses (adjustments) of the system are central to the definition of the effective forcing that results from a change in atmospheric composition. In many cases, the adjustment, rather than the characterization of the compositional perturbation (associated, for instance, with changing greenhouse gas concentrations, or aerosol burdens), limits accurate determination of the radiative forcing. Changes in clouds contribute importantly to this adjustment and thus contribute both to uncertainty in estimates of radiative forcing and to uncertainty in the response. Models are indispensable to calculation of the adjustment of the system to a compositional change but are known to be flawed in their representation of clouds. Advances in tracking Earth's energy flows and compositional changes on daily through decadal timescales are shown to provide both a critical and constructive framework for advancing model development and evaluation.

  20. Psychophysiological correlates of flow during daily activities.

    PubMed

    Gaggioli, Andrea; Cipresso, Pietro; Serino, Silvia; Riva, Giuseppe

    2013-01-01

    Flow is an optimal experience characterized by the perception of high challenges and high skills, positive affect, complete absorption in the activity carried out and intrinsic motivation. Although much research has examined the psychological features of flow, little is known about its biological underpinnings. The present study aimed at contributing to this gap by investigating the psychophysiological correlates of flow experience during daily routines. To this end, 15 university students took part in an experience sampling study, in which they provided real-time information on daily activities and associated experience while cardiac activity was monitored. After seven days of observation, 32 flow events were identified among 10 participants. A multilevel regression analysis revealed a significant correlation between optimal experience and specific cardiovascular indexes. In particular, the experience of flow was associated with increased heart rate and increased LF/HF ratio, suggesting relative sympathetic enhancement. These findings are in line with those obtained by previous related studies and indicate the feasibility of investigating physiological correlates of subjective experience in ecological contexts. PMID:23792845

  1. California energy flow in 1992

    SciTech Connect

    Borg, I.Y.; Briggs, C.K.

    1994-04-01

    For the past 16 years energy flow diagrams for the State of California have been prepared from available data by members of the Lawrence Livermore National Laboratory. They have proven to be useful tools in graphically expressing energy supply and use in the State as well as illustrating the difference between particular years and between the State and the US as a whole. As far as is possible, similar data sources have been used to prepare the diagrams from year to year and identical assumptions{sup la-le} concerning conversion efficiencies have been made in order to minimize inconsistencies in the data and analyses. Sources of data used in this report are given in Appendix B and C; unavoidably the sources used over the 1976--1993 period have varied as some data bases are no longer available. In addition, we continue to see differences in specific data reported by different agencies for a given year. In particular, reported data on supply and usage in industrial/commercial/residential end-use categories have shown variability amongst the data gathering agencies, which bars detailed comparisons from year to year. Nonetheless, taken overall, valid generalizations can be made concerning gross trends and changes.

  2. Calculated viscosity-distance dependence for some actively flowing lavas

    NASA Technical Reports Server (NTRS)

    Pieri, David

    1987-01-01

    The importance of viscosity as a gauge of the various energy and momentum dissipation regimes of lava flows has been realized for a long time. Nevertheless, despite its central role in lava dynamics and kinematics, it remains among the most difficult of flow physical properties to measure in situ during an eruption. Attempts at reconstructing the actual emplacement viscosities of lava flows from their solidified topographic form are difficult. Where data are available on the position of an advancing flow front as a function of time, it is possible to calculate the effective viscosity of the front as a function of distance from the vent, under the assumptions of a steady state regime. As an application and test of an equation given, relevant parameters from five recent flows on Mauna Loa and Kilauea were utilized to infer the dynamic structure of their aggregate flow front viscosity as they advanced, up to cessation. The observed form of the viscosity-distance relation for the five active Hawaiian flows examined appears to be exponential, with a rapid increase just before the flows stopped as one would expect.

  3. Energy efficiency study on axial flow impellers

    Microsoft Academic Search

    Jie Wu; Lachlan J. Graham; Bon Nguyen; M. Nabil Noui Mehidi

    2006-01-01

    Theoretical equations are developed to relate the flow velocities in a tank with impeller power consumption, flow circulation efficiency index NQ\\/P01\\/3 and other parameters. A non-dimensional parameter ?=V\\/((P\\/(?T2))1\\/3) has been used to characterise the velocity energy efficiency. Laser Doppler velocimetry measurement studies were carried out on the flow field produced by a few commercial axial flow hydrofoil impellers and pitch

  4. Magnetic energy flow in the solar wind.

    NASA Technical Reports Server (NTRS)

    Modisette, J. L.

    1972-01-01

    Discussion of the effect of rotation (tangential flow) of the solar wind on the conclusions of Whang (1971) suggesting an increase in the solar wind velocity due to the conversion of magnetic energy to kinetic energy. It is shown that the effect of the rotation of the sun on the magnetic energy flow results in most of the magnetic energy being transported by magnetic shear stress near the sun.

  5. Observing and modeling Earths energy flows

    Microsoft Academic Search

    Stevens B; Schwartz S

    2012-01-01

    This article reviews, from the authors perspective, progress in observing and modeling energy flows in Earth's climate system. Emphasis is placed on the state of understanding of Earth's energy flows and their susceptibility to perturbations, with particular emphasis on the roles of clouds and aerosols. More accurate measurements of the total solar irradiance and the rate of change of ocean

  6. Science Activities in Energy: Solar Energy.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Presented is a science activities in energy package which includes 12 activities relating to solar energy. Activities are simple, concrete experiments for fourth, fifth, and sixth grades, which illustrate principles and problems relating to energy. Each activity is outlined on a single card which is introduced by a question. A teacher's supplement…

  7. Transitioning Active Flow Control to Applications

    Microsoft Academic Search

    Ronald D. Joslin; Lucas G. Horta; Fang-Jenq Chen

    1999-01-01

    Active Flow Control Programs at NASA, the U.S.Air Force, and DARPA have been initiated with thegoals of obtaining revolutionary advances inaerodynamic performance and maneuveringcompared to conventional approaches. Theseprograms envision the use of actuators, sensors,and controllers on applications such as aircraftwings\\/tails, engine nacelles, internal ducts,nozzles, projectiles, weapons bays, andhydrodynamic vehicles. Anticipated benefits offlow control include reduced weight, part...

  8. Energy Flow: Flow Charts Illustrating United States Energy Resources and Usage, from Lawrence Livermore National Laboratory

    DOE Data Explorer

    Decision makers have long recognized the importance of visualizing energy and material flows in a way that distinguishes between resources, transformations and services. Research priorities can be defined in terms of changes to the flows, and the consequences of policy or technology shifts can be traced both upstream and downstream. The usefulness of this top-down view is limited by the level of detail that can be conveyed in a single image. We use two techniques to balance information content with readability. First we employe visualization techniques, such as those embodied in the energy Sankey diagram below (Figure 1), to display both qualitative (relative line weight) and quantitative (listed values) information in a reader-friendly package. The second method is to augment static images with dynamic, scalable digital content containing multiple layers (e.g. energy, carbon and economic data). This transitions the audience from that of a passive reader to an active user of the information. When used in conjunction these approaches enable relatively large, interconnected processes to be described and analyzed efficiently. [copied from the description at http://en.openei.org/wiki/LLNL_Energy_Flow_Charts#cite_note-1

  9. Introduction to Alternative and Renewable Energy: Energy Flow Analytics

    NSDL National Science Digital Library

    This module is intended for use in a college-level introductory course in alternative and renewable energy. The document covers energy flow analytics. Several useful graphics are included which provide data on energy flow and consumption as well as US transportation consumption. This module may be downloaded in PDF file format.

  10. Thermal energy scavenger (flow control)

    SciTech Connect

    Hochstein, P.A.; Milton, H.W.; Pringle, W.L.

    1981-12-22

    A thermal energy scavenger assembly is described including a plurality of temperature-sensitive wires made of material which exhibits shape memory due to a thermoelastic, martensitic phase transformation. The wires are placed in tension between fixed and movable plates which are, in turn, supported by a pair of wheels which are rotatably supported by a housing for rotation about a central axis. A pair of upper and lower cams are fixed to the housing and cam followers react with the respective cams. Each cam transmits forces through a pair of hydraulic pistons. One of the pistons is connected to a movable plate to which one end of the wires are connected whereby a stress is applied to the wires to strain the wires during a first phase and whereby the cam responds to the unstraining of the wires during a second phase. A housing defines fluid compartments through which hot and cold fluid passes and flows radially through the wires whereby the wires become unstrained and shorten in length when subjected to the hot fluid for causing a reaction between the cam followers and the cams to effect rotation of the wheels about the central axis of the assembly, which rotation of the wheels is extracted through beveled gearing. The wires are grouped into a plurality of independent modules with each module having a movable plate, a fixed plate and the associated hydraulic pistons and cam follower. The hydraulic pistons and cam follower of a module are disposed at ends of the wires opposite from the ends of the wires at which the same components of the next adjacent modules are disposed so that the cam followers of alternate modules react with one of the cams and the remaining cam followers of the remaining modules react with the other cam. There is also including stress limiting means in the form of coil springs associated with alternate ends of the wires for limiting the stress or strain in the wires.

  11. Energy flow in acoustic black holes

    SciTech Connect

    Choy, K.; Kruk, T.; Carrington, M.E.; Fugleberg, T.; Zahn, J.; Kobes, R.; Kunstatter, G.; Pickering, D. [Department of Physics, Brandon University, Brandon, Manitoba, R7A 6A9 (Canada) and Winnipeg Institute for Theoretical Physics, Winnipeg, Manitoba (Canada); Department of Physics, University of Winnipeg, Winnipeg, Manitoba, R7A 6A9 (Canada) and Winnipeg Institute for Theoretical Physics, Winnipeg, Manitoba (Canada); Department of Mathematics, Brandon University, Brandon, Manitoba, R7A 6A9 (Canada)

    2006-05-15

    We present the results of an analysis of superradiant energy flow due to scalar fields incident on an acoustic black hole. In addition to providing independent confirmation of the recent results in [E. Berti, V. Cardoso, and J. P. S. Lemos, Phys. Rev. D 70, 124006 (2004).], we determine in detail the profile of energy flow everywhere outside the horizon. We confirm explicitly that in a suitable frame the energy flow is inward at the horizon and outward at infinity, as expected on physical grounds.

  12. Colony Rheology: Active Arthropods Generate Flows

    NASA Astrophysics Data System (ADS)

    Daniels, Karen; Mann, Michael; Charbonneau, Patrick

    2015-03-01

    Hydrodynamic-like flows are observed in biological systems as varied as bacteria, insects, birds, fish, and mammals. Both the phenomenology (e.g. front instabilities, milling motions) and the interaction types (hydrodynamic, direct contact, psychological, excluded-volume) strongly vary between systems, but a question common to all of them is to understand the role of particle-scale fluctuations in controlling large-scale rheological behaviors. We will address these questions through experiments on a new system, Tyrolichus casei (cheese mites), which live in dense, self-mixing colonies composed of a mixture of living mites and inert flour/detritus. In experiments performed in a Hele-Shaw geometry, we observe that the rheology of a colony is strongly dependent on the relative concentration of active and inactive particles. In addition to spreading flows, we also observe that the system can generate convective circulation and auto-compaction.

  13. Spectral finite elements combined with energy flow techniques: Hybrid approach for the energy flow parameters evaluation

    Microsoft Academic Search

    Mohammed Ichchou; Louis Jezequel

    2002-01-01

    Energy flow parameters involved in many energy flow techniques (statistical energy analysis, or its local formats) are mainly deduced from pure analytical basic theories. However, in practice, application of SEA or alternatives to complex realistic structures suffers from the choice of subsystems and needed relevant inputs. This paper proposes a procedure which reuses existing reduced finite element modeling of the

  14. Flow control using energy deposition at Mach 5

    NASA Astrophysics Data System (ADS)

    Leichao, L.

    In recent years, energy deposition has been suggested as a novel flow control technique in high-speed flow with preferable characteristics like non-intrusive, easy arrangement and high actuation frequency. The motivation of this work is to experimentally explore the flow behaviour after the certain amount of energy is deposited in Mach 5 flow. The energy deposition is implemented using a thermal bump (surface energy deposition) and laser beam focusing (volumetric energy deposition). This work starts with the development of a measurement technique of luminescent paint for the present challenging hypersonic testing environment, which is used for the further energy deposition experiment. The successes of the luminescent paint development is demonstrated both on two-dimensional and axisymmetric models. The luminescent paint shows high spatial resolution and the accuracy comparing to the pressure transducer reading. The surface energy deposition is performed using an embedded heating element (thermal bump) on a flat plate. Qualitative and quantitative measurement techniques are utilised to study the modification to the flow structure and the alteration to the distribution of pressure and heat transfer rate after thermal bump is activated. For the volumetric energy deposition, the laser beam is firstly focused in quiescent air in order to understand the induced flow pattern and the impingement to a solid plate. High-speed schlieren photography is utilised to provide an insight to the dynamic evolution of the induced shock wave propagation and plasma kernel development after laser-induced air breakdown. Then, the laser energy deposition is conducted over a flat plate with the presence of Mach 5 flow. The outward motion of the induced shock wave significantly distorts the boundary layer and changes the surface pressure distribution.

  15. Supersonic flow with feeding of energy

    NASA Technical Reports Server (NTRS)

    Zaremba, W.

    1985-01-01

    The present work discusses the results of some experimental studies on the possibility of attenuating shock waves in a supersonic flow. The shock waves were formed by an external source of electrical energy. An electromechanical method is described that permits partial recovery of the expended energy.

  16. Energy flow observables in hadronic collisions

    E-print Network

    F. Hautmann

    2012-05-24

    We present recent QCD calculations of energy flow distributions associated with the production of jets at wide rapidity separations in high-energy hadron collisions, and discuss the role of these observables to analyze contributions from parton showering and from multiple parton collisions.

  17. Energy flows : empowering New Orleans

    E-print Network

    Guiraud, Florence Nathalie

    2012-01-01

    This thesis claims to develop alternative energy-harvesting systems by looking at their implementation at the residential scale in order to facilitate the economical autonomy of a community and thus improve its living ...

  18. Energy flows, metabolism and translation.

    PubMed

    Pascal, Robert; Boiteau, Laurent

    2011-10-27

    Thermodynamics provides an essential approach to understanding how living organisms survive in an organized state despite the second law. Exchanges with the environment constantly produce large amounts of entropy compensating for their own organized state. In addition to this constraint on self-organization, the free energy delivered to the system, in terms of potential, is essential to understand how a complex chemistry based on carbon has emerged. Accordingly, the amount of free energy brought about through discrete events must reach the strength needed to induce chemical changes in which covalent bonds are reorganized. The consequence of this constraint was scrutinized in relation to both the development of a carbon metabolism and that of translation. Amino acyl adenylates involved as aminoacylation intermediates of the latter process reach one of the higher free energy levels found in biochemistry, which may be informative on the range in which energy was exchanged in essential early biochemical processes. The consistency of this range with the amount of energy needed to weaken covalent bonds involving carbon may not be accidental but the consequence of the above mentioned thermodynamic constraints. This could be useful in building scenarios for the emergence and early development of translation. PMID:21930587

  19. Energy flows, metabolism and translation

    PubMed Central

    Pascal, Robert; Boiteau, Laurent

    2011-01-01

    Thermodynamics provides an essential approach to understanding how living organisms survive in an organized state despite the second law. Exchanges with the environment constantly produce large amounts of entropy compensating for their own organized state. In addition to this constraint on self-organization, the free energy delivered to the system, in terms of potential, is essential to understand how a complex chemistry based on carbon has emerged. Accordingly, the amount of free energy brought about through discrete events must reach the strength needed to induce chemical changes in which covalent bonds are reorganized. The consequence of this constraint was scrutinized in relation to both the development of a carbon metabolism and that of translation. Amino acyl adenylates involved as aminoacylation intermediates of the latter process reach one of the higher free energy levels found in biochemistry, which may be informative on the range in which energy was exchanged in essential early biochemical processes. The consistency of this range with the amount of energy needed to weaken covalent bonds involving carbon may not be accidental but the consequence of the abovementioned thermodynamic constraints. This could be useful in building scenarios for the emergence and early development of translation. PMID:21930587

  20. Activities for Teaching Solar Energy.

    ERIC Educational Resources Information Center

    Mason, Jack Lee; Cantrell, Joseph S.

    1980-01-01

    Plans and activities are suggested for teaching elementary children about solar energy. Directions are included for constructing a flat plate collector and a solar oven. Activities for a solar field day are given. (SA)

  1. Redox flow cell energy storage systems

    NASA Technical Reports Server (NTRS)

    Thaller, L. H.

    1979-01-01

    NASA-Redox systems are electrochemical storage devices that use two fully soluble Redox couples, anode and cathode fluids, as active electrode materials separated by a highly selective ion exchange membrane. The reactants are contained in large storage tanks and pumped through a stack of Redox flow cells where the electrochemical reactions (reduction and oxidation) take place at porous carbon felt electrodes. A string or stack of these power producing cells is connected in series in a bipolar manner. Redox energy storage systems promise to be inexpensive and possess many features that provide for flexible design, long life, high reliability and minimal operation and maintenance costs. These features include independent sizing of power and storage capacity requirements and inclusion within the cell stack of a cell that monitors the state of charge of the system as a whole, and a rebalance cell which permits continuous correction to be made for minor side reactions that would tend to result in the anode fluid and cathode fluids becoming electrochemically out of balance. These system features are described and discussed.

  2. Two-phase refrigerant flow instability analysis and active control in transient electronics cooling systems

    E-print Network

    Peles, Yoav

    -generation electronic systems, such as radar, di- rected-energy lasers, and electromagnetic weapons, will exceed 1000 WTwo-phase refrigerant flow instability analysis and active control in transient electronics cooling Accepted 26 July 2010 Available online 21 August 2010 Keywords: Electronics cooling Flow instability

  3. California energy flow in 1991

    SciTech Connect

    Borg, I.Y.; Briggs, C.K.

    1993-04-01

    Energy consumption in California fell in 1991 for the first time in five years. The State`s economy was especially hard hit by a continuing national recession. The construction industry for the second year experienced a dramatic downturn. Energy use in the industrial sector showed a modest increase, but consumption in other end-use categories declined. The decrease in energy used in transportation can be traced to a substantial fall in the sales of both highway diesel fuels and vessel bunkering fuels at California ports, the latter reflecting a mid-year increase in taxes. Gasoline sales by contrast increased as did the number of miles traveled and the number of automobiles in the State. Production in California`s oil and gas fields was at 1990 levels thus arresting a steady decline in output. Due to enlarged steam flooding operations, production at several fields reached record levels. Also countering the decline in many of California fields was new production from the Port Arguello offshore field. California natural gas production, despite a modest 1991 increase, will not fill the use within the State. Petroleum comprised more than half of the State`s energy supply principally for transportation. Natural gas use showed a small increase. Oil products play virtually no role in electrical production. The largest single source of electricity to the State is imports from the Pacific Northwest and from coal-fired plants in the Southwest. Combined contributions to transmitted electricity from renewable and alternate sources declined as hydropower was constrained by a prolonged drought and as geothermal power from the largest and oldest field at The Geysers fell. Windpower grew slightly; however solar power remained at 1990 levels and made no substantial contribution to total power generation.

  4. Science Activities in Energy: Solar Energy II.

    ERIC Educational Resources Information Center

    Oak Ridge Associated Universities, TN.

    Included in this science activities energy package are 14 activities related to solar energy for secondary students. Each activity is outlined on a single card and is introduced by a question such as: (1) how much solar heat comes from the sun? or (2) how many times do you have to run water through a flat-plate collector to get a 10 degree rise in…

  5. California energy flow in 1993

    NASA Astrophysics Data System (ADS)

    Borg, I. Y.; Briggs, C. K.

    1995-04-01

    Energy consumption in the state of California decreased about 3% in 1993 reflecting continuation of the recession that was manifest in a moribund construction industry and a high state unemployment that ran counter to national recovery trends. Residential/commercial use decreased slightly reflecting a mild winter in the populous southern portion of the state, a decrease that was offset to some extent by an increase in the state population. Industrial consumption of purchased energy declined substantially as did production of self-generated electricity for in-house use. Consumption in the transportation sector decreased slightly. The amount of power transmitted by the utilities was at 1992 levels; however a smaller proportion was produced by the utilities themselves. Generation of electricity by nonutilities, primarily cogenerators and small power producers, was the largest of any state in the US. The growth in the number of private power producers combined with increased amounts of electricity sold to the public utilities set the stage for the sweeping proposals before the California Public Utility Commission to permit direct sales from the nonutilities to retail customers. California production of both oil and natural gas declined; however, to meet demand only the imports of natural gas increased. A break in the decade-long drought during the 1992-1993 season resulted in a substantial increase in the amount of hydroelectricity generated during the year. Geothermal energy's contribution increased substantially because of the development of new resources by small power producers. Decline in steam production continued at The Geysers, the state's largest field, principally owned and managed by a public utility. Increases in windpower constituted 1-1/2% of the total electric supply, up slightly from 1992. Several solar photovoltaic demonstration plants were in operation, but their contribution remained small.

  6. The Evolution of Photospheric Flows in Active Regions

    NASA Astrophysics Data System (ADS)

    Muglach, K.; Schuck, P. W.; Hoeksema, J. T.; Sun, X.; Liu, Y.

    2010-12-01

    We will present first results of an analysis of the photospheric flow field in and around active region AR 11066. It emerged on 2nd May, 2010 near central meridian and developed into a small active region with simple bipolar structure. We will use SDO/HMI data to estimate the photospheric flow field applying the optical flow technique DAVE4VM (differential affine velocity estimator for vector magnetograms). Using both line-of-sight and vector magnetograms we will study the evolution of the photospheric flow velocity during the early stage of development of the active region.

  7. ENTRAINED-FLOW ADSORPTION OF MERCURY USING ACTIVATED CARBON

    EPA Science Inventory

    Bench-scale experiments were conducted in a flow reactor to simulate entrained-flow capture of elemental mercury (Hg) by activated carbon. Adsorption of Hg by several commercial activated carbons was examined at different carbon-to-mercury (C:Hg) ratios (by weight) (600:1 - 29000...

  8. Soap film flow visualization investigations of oscillating wing energy harvesters

    NASA Astrophysics Data System (ADS)

    Kirschmeier, Benjamin; Bryant, Matthew

    2015-03-01

    With increasing population and proliferation of wireless electronics, significant research attention has turned to harvesting energy from ambient sources such as wind and water flows at scales ranging from micro-watt to mega-watt levels. One technique that has recently attracted attention is the application of bio-inspired flapping wings for energy harvesting. This type of system uses a heaving and pitching airfoil to extract flow energy and generate electricity. Such a device can be realized using passive devices excited by aeroelastic flutter phenomena, kinematic mechanisms driven by mechanical linkages, or semi-active devices that are actively controlled in one degree of freedom and passively driven in another. For these types of systems, numerical simulations have showed strong dependence on efficiency and vortex interaction. In this paper we propose a new apparatus for reproducing arbitrary pitch-heave waveforms to perform flow visualization experiments in a soap film tunnel. The vertically falling, gravity driven soap film tunnel is used to replicate flows with a chord Reynolds number on the order of 4x104. The soap film tunnel is used to investigate leading edge vortex (LEV) and trailing edge vortex (TEV) interactions for sinusoidal and non-sinusoidal waveforms. From a qualitative analysis of the fluid structure interaction, we have been able to demonstrate that the LEVs for non-sinusoidal motion convect faster over the airfoil compared with sinusoidal motion. Signifying that optimal flapping frequency is dependent on the motion profile.

  9. Quantum Processes and Energy-Momentum Flow

    E-print Network

    B. J. Hiley; D. Robson

    2014-11-28

    In this paper we focus on energy flows in simple quantum systems. This is achieved by concentrating on the quantum Hamilton-Jacobi equation. We show how this equation appears in the standard quantum formalism in essentially three different but related ways, from the standard Schr\\"{o}dingier equation, from Lagrangian field theory and from the von Neumann-Moyal algebra. This equation allows us to track the energy flow using the energy-momentum tensor, the components of which are related to weak values of the four-momentum operator. This opens up a new way to explore these components empirically. The algebraic approach enables us to discuss the physical significance of the underlying non-commutative symplectic geometry, raising questions as to the structure of particles in quantum systems.

  10. Dark energy in flows of galaxies

    NASA Astrophysics Data System (ADS)

    Chernin, A. D.

    2015-06-01

    It has traditionally been taken for granted that Hubble's law is the key relation in cosmology, while it is surprisingly mysterious on the local scales of 1-30 Mpc where it was originally discovered. The progress in observational cosmology and, in particular, the discovery of dark energy have changed the views, and now we see that Hubble's law works hardly at truly cosmological distances, but it rules very well on local scales. Recent observations with the HST, in combination with a theory model of the local expansion flows, give a clear evidence to the presence of dark energy in the local universe. It is dark energy that dominates the dynamics of the local flows and introduces to them the approximately linear velocity-distance relation with nearly universal expansion time-rate.

  11. Energy End-Use Flow Maps for the Buildings Sector

    SciTech Connect

    Belzer, David B.

    2006-12-04

    Graphical presentations of energy flows are widely used within the industrial sector to depict energy production and use. PNNL developed two energy flow maps, one each for the residential and commercial buildings sectors, in response to a need for a clear, concise, graphical depiction of the flows of energy from source to end-use in the building sector.

  12. Active control of flow and heat transfer in silicon microchannels

    NASA Astrophysics Data System (ADS)

    Liu, Guohua; Xu, Jinliang; Yang, Yongping; Zhang, Wei

    2010-04-01

    Boiling heat transfer in silicon microchannels needs high walls and liquid superheats for bubble nucleation, leading to a strong thermal non-equilibrium between vapor and liquid phases, which not only damages the heat transfer device at the start-up stage, but also causes two-phase flow instabilities. In this paper, the seed bubble technique is used as an active control strategy to improve the flow and heat transfer in silicon microchannels. Seed bubbles are miniature bubbles of micron size, which are produced on a set of microheaters upstream of microchannels driven by pulse voltage signal. They flow downstream of microchannels after they depart from microheaters to decrease and control the thermal non-equilibrium between vapor and liquid phases in microchannels. The working fluid was methanol and the hydraulic diameter of the microchannels was 100 µm. The demand curves of pressure drops versus mass fluxes were examined with and without active control. Four regions (I, II, III and IV) of demand curves were identified. For the flow without active control, the four regions were the subcooled liquid flow, the superheated liquid flow, the unstable boiling flow and the vapor flow at high-vapor-mass qualities. Alternatively, for the flow with active control, the four regions were the subcooled liquid flow, the seed-bubble-triggered boiling flow, the seed-bubble-stabilized boiling flow and the vapor flow at high-vapor-mass qualities. The linear part of the demand curves is shortened when the seed bubble technique is used. The points at which the demand curves deviate from the linear part coincide into one point at different seed bubble frequencies. The seed bubbles have no influence on the subcooled liquid flow (region I) and the vapor flow at high-vapor-mass qualities (region IV). However, seed bubbles not only convert a superheated liquid flow into a quasi-stable boiling flow in region II, but also convert an unstable boiling flow into a quasi-stable boiling flow in region III. Besides, heat transfer coefficients with active control are several times those without active control in regions II and III. The higher the seed bubble frequencies, the more the heater surface temperatures decrease.

  13. Activation of cyclic electron flow by hydrogen peroxide in vivo

    PubMed Central

    Strand, Deserah D.; Livingston, Aaron K.; Satoh-Cruz, Mio; Froehlich, John E.; Maurino, Veronica G.; Kramer, David M.

    2015-01-01

    Cyclic electron flow (CEF) around photosystem I is thought to balance the ATP/NADPH energy budget of photosynthesis, requiring that its rate be finely regulated. The mechanisms of this regulation are not well understood. We observed that mutants that exhibited constitutively high rates of CEF also showed elevated production of H2O2. We thus tested the hypothesis that CEF can be activated by H2O2 in vivo. CEF was strongly increased by H2O2 both by infiltration or in situ production by chloroplast-localized glycolate oxidase, implying that H2O2 can activate CEF either directly by redox modulation of key enzymes, or indirectly by affecting other photosynthetic processes. CEF appeared with a half time of about 20 min after exposure to H2O2, suggesting activation of previously expressed CEF-related machinery. H2O2-dependent CEF was not sensitive to antimycin A or loss of PGR5, indicating that increased CEF probably does not involve the PGR5-PGRL1 associated pathway. In contrast, the rise in CEF was not observed in a mutant deficient in the chloroplast NADPH:PQ reductase (NDH), supporting the involvement of this complex in CEF activated by H2O2. We propose that H2O2 is a missing link between environmental stress, metabolism, and redox regulation of CEF in higher plants. PMID:25870290

  14. Energy efficient continuous flow ash lockhopper

    NASA Technical Reports Server (NTRS)

    Collins, Earl R., Jr. (inventor); Suitor, Jerry W. (inventor); Dubis, David (inventor)

    1989-01-01

    The invention relates to an energy efficient continuous flow ash lockhopper, or other lockhopper for reactor product or byproduct. The invention includes an ash hopper at the outlet of a high temperature, high pressure reactor vessel containing heated high pressure gas, a fluidics control chamber having an input port connected to the ash hopper's output port and an output port connected to the input port of a pressure letdown means, and a control fluid supply for regulating the pressure in the control chamber to be equal to or greater than the internal gas pressure of the reactor vessel, whereby the reactor gas is contained while ash is permitted to continuously flow from the ash hopper's output port, impelled by gravity. The main novelty resides in the use of a control chamber to so control pressure under the lockhopper that gases will not exit from the reactor vessel, and to also regulate the ash flow rate. There is also novelty in the design of the ash lockhopper shown in two figures. The novelty there is the use of annular passages of progressively greater diameter, and rotating the center parts on a shaft, with the center part of each slightly offset from adjacent ones to better assure ash flow through the opening.

  15. Piezoelectric energy harvesting from flow-induced vibration

    Microsoft Academic Search

    D.-A. Wang; H.-H. Ko

    2010-01-01

    A new piezoelectric energy harvester for harnessing energy from flow-induced vibration is developed. It converts flow energy into electrical energy by piezoelectric conversion with oscillation of a piezoelectric film. A finite element model is developed in order to estimate the generated voltage of the piezoelectric laminate subjected to a distributed load. Prototypes of the energy harvester are fabricated and tested.

  16. Flow dimensions on daily activities with the Spanish version of the Flow Scale (DFS).

    PubMed

    Rufi, Sergi; Javaloy, Federico; Batista-Foguet, Joan M; Solanas, Antonio; Páez, Darío

    2014-01-01

    A sample of 250 students of psychology with an average age of 20.37 years, answered the Flow Q questionnaire indicating their favorite flow activity, and the Spanish version of the Dispositional Flow Scale (DFS). A confirmatory factor analysis assessed the DFS construct validity of the flow model on daily activities. Both a hierarchical model of eight first order factors reflecting a second order global flow factor, and a model with eight formative first order flow dimensions, showed good fit and discriminant power. Most optimal activities were found to be individual and structured, such as studying, reading and certain forms of individual sports. Leisure activities turned out to be more rewarding than studying. Sports displayed more flow, clear goals, merging of action and awareness, and autotelic experience. Reading also showed more flow, balance of challenge and skills, feedback, merging of action and awareness, and loss of self-consciousness. On the other hand, studying displayed less flow, merging of action and awareness, and autotelic experience. PMID:25012500

  17. ELEMENTAL MERCURY CAPTURE BY ACTIVATED CARBON IN A FLOW REACTOR

    EPA Science Inventory

    The paper gives results of bench-scale experiments in a flow reactor to simulate the entrained-flow capture of elemental mercury (Hgo) using solid sorbents. Adsorption of Hgo by a lignite-based activated carbon (Calgon FGD) was examined at different carbon/mercury (C/Hg) rat...

  18. U.S. Energy Flow - 1999

    SciTech Connect

    Kaiper, G V

    2001-03-01

    Lawrence Livermore National Laboratory (LLNL) has prepared similar flow charts of U.S. energy consumption since 1972. The chart follows the flow of individual fuels and compares these on the basis of a common energy unit of quadrillion British thermal units (Btu). A quadrillion, or ''quad,'' is 10{sup 15}. One Btu is the quantity of heat needed to raise the temperature of 1 pound of water by 1 F at or near 39.2 F. The width of each colored line across this chart is in proportion to the amount of quads conveyed. (Exception: lines showing extremely small amounts have been made wide enough to be clearly visible.) In most cases, the numbers used in this chart have been rounded to the nearest tenth of a quad, although the original data was published in hundredths or thousandths of a quad. As a consequence of independent rounding, some of the summary numbers may not appear to be a precise total of their various components. The first chart in this document uses quadrillion Btu's to conform with data from the U.S. Department of Energy's Energy Information Administration (EIA). However, the second chart is expressed in exajoules. A joule is the metric unit for heat. One Btu equals 1,055.06 joules; and one quadrillion Btu's equals 1.055 exajoules (an exajoule is 10{sup 18} joules).

  19. Active solar energy market trends

    Microsoft Academic Search

    D. M. Freidman; P. E. Mihlmester

    1983-01-01

    The analyses presented in this paper summarize the U.S. active solar market shifts or trends as depicted by the 1980 and 1981 market surveys developed for the Energy Information Administration (EIA) of the U.S. Department of Energy (DOE). The trends identified and analyzed represent the first such analyses based on extensive survey data obtained from questionnaires sent out annually to

  20. Active Shape Modeling with Electric Flows

    Microsoft Academic Search

    Herng-Hua Chang; Daniel J. Valentino; Woei-Chyn Chu

    2010-01-01

    Physics-based particle systems are an effective tool for shape modeling. Also, there has been much interest in the study of shape modeling using deformable contour approaches. In this paper, we describe a new deformable model with electric flows based upon computer simulations of a number of charged particles embedded in an electrostatic system. Making use of optimized numerical techniques, the

  1. Active Boundary Layer Trip for Supersonic Flows

    NASA Astrophysics Data System (ADS)

    Schloegel, F.; Panigua, G.; Tirtey, S.

    2009-01-01

    The last decade has been full of excitement and success for the hypersonic community thanks to various Scramjet ground tests and launches. These studies have shown promising potentials but the viability to perform commercial flights at Mach 8 is still to be demonstrated. An ideal Scramjet is one which is capable of self- starting over a wide range of angles of attack and Mach number. The Scramjet designer has to ensure that the boundary layer over the inlet ramp is fully turbulent where shocks impact, hence reducing the risks of chocked flow conditions. Most studies have issued the efficiency of roughness trip to trigger the boundary layer transition. At hypersonic speed, heat transfer and drag dramatically increase resulting in skin friction averaging at 40% of the overall drag. This study investigates the possibility of triggering transition using perpendicular air jets on a flat plate place in a hypersonic cross-flow. Experiments were conducted in the von Karman Institute hypersonic blow down wind tunnel H3. This facility is mounted with a Mach 6 contoured nozzles and provides flows with Reynolds number in the range of 10x106/m to 30x106/m. The model consist of a flat plate manufactured with a built -in settling chamber, equipped with a pressure tap and a thermocouple to monitor the jet conditions. A first flat plate was manufactured with a black-coated Plexiglas top, for surface heat transfer measurement using an infrared camera. On the second model, a Upilex sheet equipped with 32 thin film gages was glued, time dependent heat transfer measurements up to 60kHz. The jet injection conditions have been varied and a Mach number of 5.5 kept constant. The flow topology was investigated using fast schlieren techniques and oil flow, in order to gain a better understanding.

  2. U.S. Energy Flow -- 1995

    Microsoft Academic Search

    H. Miller; N. Mui; A. Pasternak

    1997-01-01

    Energy consumption in 1995 increased slightly for the fifth year in a row (from 89 to 91 quadrillion [1015<\\/sup>Btu). U.S. economic activity slowed from the fast-paced recovery of 1994, even with the continued low unemployment rates and low inflation rates. The annual increase in U.S. real GDP dropped to 4.6% from 1994�s increase of 5.8%. Energy consumption in all major

  3. High energy density Z-pinch plasmas using flow stabilization

    NASA Astrophysics Data System (ADS)

    Shumlak, U.; Golingo, R. P.; Nelson, B. A.; Bowers, C. A.; Doty, S. A.; Forbes, E. G.; Hughes, M. C.; Kim, B.; Knecht, S. D.; Lambert, K. K.; Lowrie, W.; Ross, M. P.; Weed, J. R.

    2014-12-01

    The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes - Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and scaling analyses will be presented. In addition to studying fundamental plasma science and high energy density physics, the ZaP and ZaP-HD experiments can be applied to laboratory astrophysics.

  4. Irreversible energy flow in forced Vlasov dynamics

    NASA Astrophysics Data System (ADS)

    Plunk, Gabriel G.; Parker, Joseph T.

    2014-10-01

    The recent paper of Plunk [G.G. Plunk, Phys. Plasmas 20, 032304 (2013)] considered the forced linear Vlasov equation as a model for the quasi-steady state of a single stable plasma wavenumber interacting with a bath of turbulent fluctuations. This approach gives some insight into possible energy flows without solving for nonlinear dynamics. The central result of the present work is that the forced linear Vlasov equation exhibits asymptotically zero (irreversible) dissipation to all orders under a detuning of the forcing frequency and the characteristic frequency associated with particle streaming. We first prove this by direct calculation, tracking energy flow in terms of certain exact conservation laws of the linear (collisionless) Vlasov equation. Then we analyze the steady-state solutions in detail using a weakly collisional Hermite-moment formulation, and compare with numerical solution. This leads to a detailed description of the Hermite energy spectrum, and a proof of no dissipation at all orders, complementing the collisionless Vlasov result. Contribution to the Topical Issue "Theory and Applications of the Vlasov Equation", edited by Francesco Pegoraro, Francesco Califano, Giovanni Manfredi and Philip J. Morrison.

  5. Aerodynamic Flow Control using Distributed Active Bleed

    NASA Astrophysics Data System (ADS)

    Kearney, John M.; Glezer, Ari

    2010-11-01

    The aerodynamic effects of large-area air bleed that is driven through surface openings by pressure differences across a lifting airfoil and regulated by addressable, arrays of integrated louvers have been investigated in wind tunnel experiments. Time-dependent interactions between the bleed and cross flows alter the apparent aerodynamic shape of the lifting surface and consequently the distributions of aerodynamic forces and moments. The lift and pitching moment can be significantly altered over a wide range of angles of attack from pre- to post-stall by independently-controlled bleed near the leading (LE) and trailing (TE) edges. While TE bleed effects nearly-linear variation of the pitching moment with minimal changes in lift, LE bleed leads to large variations in lift and pitching moment with minimal drag penalty. Phase-locked PIV shows the effects of the bleed on the flow on the suction surface and in the near wake. Supported by AFOSR

  6. Numerical simulations of laser energy deposition for supersonic flow control

    Microsoft Academic Search

    Ramnath Kandala

    2005-01-01

    This thesis deals with the computational study of localized laser energy deposition in supersonic flows. This study is part of an effort to develop dynamic flow control mechanisms which can tackle critical flow conditions occurring due to shock-shock interactions in high speed flight. A model for Nd:YAG laser energy deposition in air has been developed for the purpose of this

  7. Sleep Management on Multiple Machines for Energy and Flow Time

    E-print Network

    Lam, Tak-Wah

    Sleep Management on Multiple Machines for Energy and Flow Time Sze-Hang Chan Tak-Wah Lam Lap extends the traditional study of online flow-time scheduling on multiple machines to take sleep management machine to further optimize energy usage. Like the previous work on the tradeoff between flow time

  8. [Energy flow in arctic aquatic ecosystems

    SciTech Connect

    Schell, D.M.

    1985-01-01

    This study is aimed at determining the major pathways of energy flow in freshwater ecosystems of the Alaskan arctic coastal plain. Selected sites for study of the processes supplying energy to streams and lakes to verify the generality of past findings will be surveyed for collection of organisms including the Colville River drainage and the lake region around Teshekpuk Lake. Specific objectives are to collect food web apex organisms (fish and birds) from a variety of sites in the coastal plain to verify descriptive models of ecosystem structure and food web pathways and to compare the utilization rates by insect larvae of fresh litter and in situ primary production relative to more refractory peaty materials through seasonal sampling for isotopic analysis.

  9. [Energy flow in arctic aquatic ecosystems

    SciTech Connect

    Schell, D.M.

    1985-12-31

    This study is aimed at determining the major pathways of energy flow in freshwater ecosystems of the Alaskan arctic coastal plain. Selected sites for study of the processes supplying energy to streams and lakes to verify the generality of past findings will be surveyed for collection of organisms including the Colville River drainage and the lake region around Teshekpuk Lake. Specific objectives are to collect food web apex organisms (fish and birds) from a variety of sites in the coastal plain to verify descriptive models of ecosystem structure and food web pathways and to compare the utilization rates by insect larvae of fresh litter and in situ primary production relative to more refractory peaty materials through seasonal sampling for isotopic analysis.

  10. Forward energy flow and diffraction at ATLAS

    E-print Network

    Staroba, P; The ATLAS collaboration

    2012-01-01

    First measurements of forward energy flow and diffractive dissociation processes at ATLAS are presented. Measurements are based on 7 TeV minimum bias (7.1?b?1) and dijet (585?b?1) data samples taken during March-May 2010 in the low pileup accelerator setup. Measurement of transverse energy density as a function of pseudorapidity was performed using the full acceptance of ATLAS detectors. Stable charged particles with PT > 500 MeV and stable neutral particles with PT > 200 MeV were included. Manifestation of diffractive processes of three classes (single, double and central diffractive dissociation) was studied using inelastic differential cross section in forward rapidity gap size ??F bins. Experimental distributions are compared with several Monte Carlo predictions (PYTHIA6, PYTHIA8, PHOJET, HERWIG++ and EPOS) using different tunes.

  11. Predicting flow at work: investigating the activities and job characteristics that predict flow states at work.

    PubMed

    Nielsen, Karina; Cleal, Bryan

    2010-04-01

    Flow (a state of consciousness where people become totally immersed in an activity and enjoy it intensely) has been identified as a desirable state with positive effects for employee well-being and innovation at work. Flow has been studied using both questionnaires and Experience Sampling Method (ESM). In this study, we used a newly developed 9-item flow scale in an ESM study combined with a questionnaire to examine the predictors of flow at two levels: the activities (brainstorming, planning, problem solving and evaluation) associated with transient flow states and the more stable job characteristics (role clarity, influence and cognitive demands). Participants were 58 line managers from two companies in Denmark; a private accountancy firm and a public elder care organization. We found that line managers in elder care experienced flow more often than accountancy line managers, and activities such as planning, problem solving, and evaluation predicted transient flow states. The more stable job characteristics included in this study were not, however, found to predict flow at work. PMID:20364915

  12. Active Control of Tip Leakage Flows

    NASA Astrophysics Data System (ADS)

    Breuer, Kenneth; Bae, Jinwoo; Kang, Eugene; Tan, Choon

    1999-11-01

    The performance of axial compressors is degraded by the leakage of fluid from the high-pressure side of the blade to the low pressure side through the narrow gap between the rotating blade and the stationary casing. Controlling such leakage can improve stage performance and improve compressor stability. We report on two methods to control such tip leakage flows using momentum injection located on the casing wall. The first method uses a synthetic jet to create a fluidic wall which reduces the effective gap between the blade and the casing and thus reduces mass flow for a given pressure difference. The second control method artificially forces the tip leakage jet at its natural frequency, increasing its spreading rate, and thus reducing the total pressure loss in the compressor passage. Experimental results from both prototypical experimental rigs and a full compressor cascade rig are presented illustrating the dependence on actuator amplitude, forcing frequency, and geometric variations on the success and cost of both control methods.

  13. Portable Liquid Flow Metering for Energy Conservation Programs 

    E-print Network

    Miles, F. J.

    1982-01-01

    Flow metering is absolutely required for evaluation of energy usage. In fact, determining usages and heat balances without metering are simply educated guesses. Recent technological innovations in flow metering have produced ...

  14. improved regularity of harmonic map flows with holder continuous energy

    E-print Network

    Topping, Peter

    improved regularity of harmonic map flows with h¨older continuous energy Peter Topping Abstract For a smooth harmonic map flow u : M × [0, T) N with blow-up as t T, it has been asked ([6], [5], [7 the harmonic map energy to be E(v) := 1 2 M | v|2 . (1.1) The harmonic map flow is the L2-gradient flow

  15. The Electrochemical Flow Capacitor: Capacitive Energy Storage in Flowable Media

    NASA Astrophysics Data System (ADS)

    Dennison, Christopher R.

    Electrical energy storage (EES) has emerged as a necessary aspect of grid infrastructure to address the increasing problem of grid instability imposed by the large scale implementation of renewable energy sources (such as wind or solar) on the grid. Rapid energy recovery and storage is critically important to enable immediate and continuous utilization of these resources, and provides other benefits to grid operators and consumers as well. In past decades, there has been significant progress in the development of electrochemical EES technologies which has had an immense impact on the consumer and micro-electronics industries. However, these advances primarily address small-scale storage, and are often not practical at the grid-scale. A new energy storage concept called "the electrochemical flow capacitor (EFC)" has been developed at Drexel which has significant potential to be an attractive technology for grid-scale energy storage. This new concept exploits the characteristics of both supercapacitors and flow batteries, potentially enabling fast response rates with high power density, high efficiency, and long cycle lifetime, while decoupling energy storage from power output (i.e., scalable energy storage capacity). The unique aspect of this concept is the use of flowable carbon-electrolyte slurry ("flowable electrode") as the active material for capacitive energy storage. This dissertation work seeks to lay the scientific groundwork necessary to develop this new concept into a practical technology, and to test the overarching hypothesis that energy can be capacitively stored and recovered from a flowable media. In line with these goals, the objectives of this Ph.D. work are to: i) perform an exploratory investigation of the operating principles and demonstrate the technical viability of this new concept and ii) establish a scientific framework to assess the key linkages between slurry composition, flow cell design, operating conditions and system performance. To achieve these goals, a combined experimental and computational approach is undertaken. The technical viability of the technology is demonstrated, and in-depth studies are performed to understand the coupling between flow rate and slurry conductivity, and localized effects arising within the cell. The outlook of EFCs and other flowable electrode technologies is assessed, and opportunities for future work are discussed.

  16. Optimal active power dispatch by network flow approach

    SciTech Connect

    Carvalho, M.F. (Instituto de Automacao Centro Tecnologico para Informatica Rod. SP 340 Km 105 13081 Campinas, SP (BR)); Soares, S.; Ohishi, T. (Faculdade de Engenharia Eletrica, Universidade de Campinas - UNICAMP, Caixa Postal 6101 13081 Campinas SP (BR))

    1988-11-01

    In this paper the optimal active power dispatch problem is formulated as a nonlinear capacitated network flow problem with additional linear constraints. Transmission flow limits and both Kirchhoff's laws are taken into account. The problem is solved by a Generalized Upper Bounding technique that takes advantage of the network flow structure of the problem. The new approach has potential applications on power systems problems such as economic dispatch, load supplying capability, minimum load shedding, and generation-transmission reliability. The paper also reviews the use of transportation models for power system analysis. A detailed illustrative example is presented.

  17. Driving magnetic activity: differential rotation, flow structures, and surface patterns

    NASA Astrophysics Data System (ADS)

    Strassmeier, Klaus G.

    2015-03-01

    The interplay between stellar rotation and turbulent flows is a major ingredient for vertical angular momentum transport in stellar convection zone. Combined with the centrifugal force and the buoyancy force due to pole-equator temperature gradients one can expect a large-scale flow structure that is usually referred to as differential rotation and meridional flows. I review such observations for stars other than the Sun, mostly for stars significantly more active, and ask the question whether such observations can constrain the dynamo process.

  18. Flow of cortical activity underlying a tactile decision in mice

    PubMed Central

    Guo, Zengcai V.; Li, Nuo; Huber, Daniel; Ophir, Eran; Gutnisky, Diego; Ting, Jonathan T.; Feng, Guoping; Svoboda, Karel

    2014-01-01

    Summary Perceptual decisions involve distributed cortical activity. Does information flow sequentially from one cortical area to another, or do networks of interconnected areas contribute at the same time? Here we delineate when and how activity in specific areas drives a whisker-based decision in mice. A short-term memory component temporally separated tactile “sensation” and “action” (licking). Using optogenetic inhibition (spatial resolution, 2 mm; temporal resolution, 100 ms) we surveyed the neocortex for regions driving behavior during specific behavioral epochs. Barrel cortex was critical for sensation. During the short-term memory, unilateral inhibition of anterior lateral motor cortex biased responses to the ipsilateral side. Consistently, barrel cortex showed stimulus-specific activity during sensation, whereas motor cortex showed choice-specific preparatory activity and movement-related activity, consistent with roles in motor planning and movement. These results suggest serial information flow from sensory to motor areas during perceptual decision making. PMID:24361077

  19. Flow of cortical activity underlying a tactile decision in mice.

    PubMed

    Guo, Zengcai V; Li, Nuo; Huber, Daniel; Ophir, Eran; Gutnisky, Diego; Ting, Jonathan T; Feng, Guoping; Svoboda, Karel

    2014-01-01

    Perceptual decisions involve distributed cortical activity. Does information flow sequentially from one cortical area to another, or do networks of interconnected areas contribute at the same time? Here we delineate when and how activity in specific areas drives a whisker-based decision in mice. A short-term memory component temporally separated tactile "sensation" and "action" (licking). Using optogenetic inhibition (spatial resolution, 2 mm; temporal resolution, 100 ms), we surveyed the neocortex for regions driving behavior during specific behavioral epochs. Barrel cortex was critical for sensation. During the short-term memory, unilateral inhibition of anterior lateral motor cortex biased responses to the ipsilateral side. Consistently, barrel cortex showed stimulus-specific activity during sensation, whereas motor cortex showed choice-specific preparatory activity and movement-related activity, consistent with roles in motor planning and movement. These results suggest serial information flow from sensory to motor areas during perceptual decision making. PMID:24361077

  20. Energy of eigenmodes in magnetohydrodynamic flows of ideal fluids

    SciTech Connect

    Khalzov, I. V.; Smolyakov, A. I. [University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N5E2 (Canada); Russian Research Center 'Kurchatov Institute', 1 Kurchatov Sq., Moscow, 123182 (Russian Federation); Ilgisonis, V. I. [Russian Research Center 'Kurchatov Institute', 1 Kurchatov Sq., Moscow, 123182 (Russian Federation)

    2008-05-15

    Energy of eigenmodes in magnetohydrodynamic (MHD) flows of ideal fluids is studied analytically. It is shown that the energy of unstable modes is zero, while the energy of stable oscillatory modes (waves) can assume both positive and negative values. Negative energy waves always correspond to eigenmodes with a finite component of the wave-vector along the flow. Coupling of negative and positive energy waves is shown to be a universal mechanism of MHD instabilities in flowing media. As an example, the energy of eigenmodes of magnetorotational instability is calculated.

  1. U.S. energy flow, 1992

    SciTech Connect

    Borg, I.Y.; Briggs, C.K.

    1993-10-01

    This report discusses energy consumption in the United States which rose slightly in 1992, reflecting partial recovery from the economic recession that prevailed during the previous year. Increases were registered in all major end use sectors with the largest occurring in the industrial sector. Energy consumed for transportation, which reflects improved passenger fleet efficiencies and a growing population as well as economic activity, returned to 1989--1990 levels. The United States depended on petroleum for 41 % of its energy supply. Imports of crude oil and petroleum products increased to compensate for decline in domestic production. Imports rose to 44% of supply. Because domestic production of natural gas was close to 1991`s, increased demand was accommodated by larger (16%) imports from Canada. Coal production was virtually unchanged from 1991 and thus well below 1990 production. Nonetheless coal supplied about one quarter of US energy needs, primarily for electrical generation. For the third year electricity transmitted by utilities departed from historic growth trends; it remained at 1991 levels. The Energy Policy Act of 1992 was signed into law in October. Among its many provisions, this act encourages independent power producers to compete with the utilities in wholesale production of electricity, streamlines the licensing of nuclear power plants, promotes the development of renewable energy sources through tax incentives, imposes efficiency standards on many manufacturing items, requires federal and private fleets to buy vehicles that run on alternative fuels, and requires the Secretary of Energy to develop a plan to decrease oil consumption, increase the use of renewable energy, improve conversion efficiencies, and limit the emission of greenhouse gases.

  2. Improving wind turbine array efficiency through active flow control

    NASA Astrophysics Data System (ADS)

    Velarde, John-Michael; Wang, Guannan; Shea, Patrick; Glauser, Mark; Castillo, Luciano

    2013-11-01

    We attempted to demonstrate the capability of instrumenting three wind turbine blades with an air delivery system that provided active flow control in an effort to improve turbine performance in the presence of the wake turbulence that is inherent in a turbine array. Presently, turbines are being designed for set conditions, such as steady incoming wind and a set velocity profile, however conditions can be drastically different in the field - thus causing poor performance from the turbines. The blades were instrumented with pressure transducers which measured the suction surface pressure; the sensor setup was such that three unique blade configurations existed: spanwise sensors, chord-wise sensors, and a reference sensor. The compressed air was delivered through a rotary union connected to the turbine hub with tubing attached to the suction side of the blades. The primary purpose of this test was to demonstrate the ability to deliver air to a rotating frame for active flow control. We collected data under three test conditions using an open-section wind tunnel, courtesy of Texas Tech University: static with no flow control, rotation with no flow control, and rotation with active flow control.

  3. ACTIVITY BUDGETS, ENERGY EXPENDITURES, AND

    Microsoft Academic Search

    FERRUGINOUS HAWKS; JAMES S. WAKELEY

    Daily energT expenditures of two pairs of nesting Ferruginous Hawks were esti- mated from activity budgets, and were compared with energy intakes determined from observed prey captures. In 1974 and 1975 respectively, the adult males expended 330.9 -+ 37.8 (SD) and 374.3 ñ 18.1 kcal\\/day, whereas the adult females expended 265.3 -+ 28.3 and 294.6 ñ 34.5 kcal\\/ day. The

  4. Active flow control on a 1:4 car model

    NASA Astrophysics Data System (ADS)

    Heinemann, Till; Springer, Matthias; Lienhart, Hermann; Kniesburges, Stefan; Othmer, Carsten; Becker, Stefan

    2014-05-01

    Lift and drag of a passenger car are strongly influenced by the flow field around its rear end. The bluff body geometry produces a detached, transient flow which induces fluctuating forces on the body, affecting the rear axle, which may distress dynamic stability and comfort significantly. The investigations presented here deal with a 1:4 scale model of a simplified test car geometry that produces fluctuating lift and drag due to its strongly rounded rear geometry. To examine the influence of active flow control on this behavior, steady air jets were realized to exhaust from thin slots across the rear in three different configurations. Investigations were performed at and included the capturing of effective integral lift and drag, velocity measurements in the surrounding flow field with Laser Doppler Anemometry, surface pressure measurements and surface oil flow visualization on the rear. The flow field was found to be dominated by two longitudinal vortices, developing from the detachment of the flow at the upper C-pillar positions, and a recirculating, transverse vortex above the rear window. With an air jet emerging from a slot across the surface right below the rear window section, tangentially directed upstream toward the roof section, total lift could be reduced by more than 7 %, with rear axle lift reduction of about 5 % and negligible drag affection (1 %).

  5. AN ACTIVE FRACTURE MODEL FOR UNSATURATED FLOW AND TRANSPORT

    SciTech Connect

    Liu, Hui-Hai; Bodvarsson, Gudmundur S.; Doughty, Christine

    1999-09-15

    Fracture/matrix (F/M) interaction is a key factor affecting flow and transport in unsaturated fractured rocks. In classic continuum approaches (Warren and Root, 1963), it is assumed that flow occurs through all the connected fractures and is uniformly distributed over the entire fracture area, which generally gives a relatively large F/M interaction. However, fractures seem to have limited interaction with the surrounding matrix at Yucca Mountain, Nevada, as suggested by geochemical nonequilibrium between the perched water (resulting mainly from fracture flow) and pore water in the rock matrix. Because of the importance of the F/M interaction and related issues, there is a critical need to develop new approaches to accurately consider the interaction reduction inferred from field data at the Yucca Mountain site. Motivated by this consideration, they have developed an active fracture model based on the hypothesis that not all connected fractures actively conduct water in unsaturated fractured rocks.

  6. Active QoS Flow Maintenance in Controlled Mobile Networks

    E-print Network

    Shenoy, Prashant

    Active QoS Flow Maintenance in Controlled Mobile Networks John D. Sweeney, Roderic Grupen to control mobility of the nodes and be aware of their internal state is that a routing fault can of Massachusetts Amherst {sweeney,grupen, shenoy}@cs.umass.edu Abstract-- Applications involving teams of mobile

  7. Correlated neuronal activity and the flow of neural information

    Microsoft Academic Search

    Emilio Salinas; Terrence J. Sejnowski

    2001-01-01

    For years we have known that cortical neurons collectively have synchronous or oscillatory patterns of activity, the frequencies and temporal dynamics of which are associated with distinct behavioural states. Although the function of these oscillations has remained obscure, recent experimental and theoretical results indicate that correlated fluctuations might be important for cortical processes, such as attention, that control the flow

  8. Closed-Loop Active Flow Control - A Collaborative Approach

    Microsoft Academic Search

    M. Samimy; M. Debiasi; E. Caraballo; J. DeBonis; J. H. Myatt

    2003-01-01

    The Collaborative Center of Control Science (CCCS) at The Ohio State University was founded very recently with funding from the Air Force Research Laboratory to conduct multidisciplinary research in the area of feedback control, with applications such as cooperative control of unmanned air vehicles (UAVs), guidance and control of hypersonic vehicles, and closed-loop active flow control. The last topic is

  9. Issues in active flow control: theory, control, simulation, and experiment

    Microsoft Academic Search

    S. Scott Collis; Ronald D. Joslin; Avi Seifert; Vassilis Theofilis

    2004-01-01

    The goal of this paper is to provide a perspective on the current status and future directions for active flow-control technology with particular emphasis on oscillatory control. This is not a comprehensive review of the literature; rather, certain issues that are often neglected in studies are highlighted showing their importance or impact on the reported observations and targeted outcomes. Feasible

  10. Oklahoma Energy Awareness Education, Energy Education Activities, Grades K-3.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Education, Oklahoma City.

    This publication contains energy education activities for grades K through 3 and is part of a set of three publications. These activities are organized under five energy concepts: (1) energy is so basic that nothing moves without it; (2) conservation of energy; (3) there are other energy alternatives; (4) society depends on energy; and (5) the…

  11. Energy principle for magnetohydrodynamic flows and Bogoyavlenskij's transformation

    E-print Network

    Ilin, Konstantin

    Energy principle for magnetohydrodynamic flows and Bogoyavlenskij's transformation K. I. Ilin 1 magnetohydrodynamic flows of an inviscid incompressible fluid is studied using the energy method. It is shown that certain symmetry transformations of steady solutions of the equations of ideal magnetohydrodynamics have

  12. Activation energy measurements in rheological analysis of cheese

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activation energy of flow (Ea) was calculated from temperature sweeps of cheeses with contrasting characteristics to determine its usefulness in predicting rheological behavior upon heating. Cheddar, Colby, whole milk Mozzarella, low moisture part skim Mozzarella, Parmesan, soft goat, and Queso Fre...

  13. Numerical laser energy deposition on supersonic cavity flow and sensor placement strategies to control the flow.

    PubMed

    Yilmaz, Ibrahim; Aradag, Selin

    2013-01-01

    In this study, the impact of laser energy deposition on pressure oscillations and relative sound pressure levels (SPL) in an open supersonic cavity flow is investigated. Laser energy with a magnitude of 100?mJ is deposited on the flow just above the cavity leading edge and up to 7?dB of reduction is obtained in the SPL values along the cavity back wall. Additionally, proper orthogonal decomposition (POD) method is applied to the x-velocity data obtained as a result of computational fluid dynamics simulations of the flow with laser energy deposition. Laser is numerically modeled using a spherically symmetric temperature distribution. By using the POD results, the effects of laser energy on the flow mechanism are presented. A one-dimensional POD methodology is applied to the surface pressure data to obtain critical locations for the placement of sensors for real time flow control applications. PMID:24363612

  14. Numerical Laser Energy Deposition on Supersonic Cavity Flow and Sensor Placement Strategies to Control the Flow

    PubMed Central

    Aradag, Selin

    2013-01-01

    In this study, the impact of laser energy deposition on pressure oscillations and relative sound pressure levels (SPL) in an open supersonic cavity flow is investigated. Laser energy with a magnitude of 100?mJ is deposited on the flow just above the cavity leading edge and up to 7?dB of reduction is obtained in the SPL values along the cavity back wall. Additionally, proper orthogonal decomposition (POD) method is applied to the x-velocity data obtained as a result of computational fluid dynamics simulations of the flow with laser energy deposition. Laser is numerically modeled using a spherically symmetric temperature distribution. By using the POD results, the effects of laser energy on the flow mechanism are presented. A one-dimensional POD methodology is applied to the surface pressure data to obtain critical locations for the placement of sensors for real time flow control applications. PMID:24363612

  15. Energy transfer process of anisothermal wall-bounded flows

    NASA Astrophysics Data System (ADS)

    Aulery, Frédéric; Toutant, Adrien; Bataille, Françoise; Zhou, Ye

    2015-07-01

    Strong temperature gradients introduce a major external agency into the wall-bounded turbulent flows. In these flows, the temperature field and the turbulent velocity field are highly correlated. In fact, standard RANS turbulent models are not able to accurately reproduce these flows. In order to improve the performance of the models, we need to understand how the energy is produced, transferred, and dissipated in a strong anisothermal wall-bounded flow. This letter presents a first detailed investigation on the roles played by each contributor in the energy transfer equation.

  16. Active Motion in Systems with Energy Supply

    Microsoft Academic Search

    Werner Ebeling; Frank Schweitzer

    2001-01-01

    Biological motion, human traffic and many other types of active motion rely on the supply of energy. In order to derive a rather general approach for active motion, we have proposed a model of active Brownian particles, which have the ability to take up energy from their environment, to store it in an internal energy depot and to convert internal

  17. Bootstrapping the Energy Flow in the Beginning of Life

    Microsoft Academic Search

    R. Hengeveld; M. A. Fedonkin

    2007-01-01

    This paper suggests that the energy flow on which all living structures depend only started up slowly, the low-energy, initial\\u000a phase starting up a second, slightly more energetic phase, and so on. In this way, the build up of the energy flow follows\\u000a a bootstrapping process similar to that found in the development of computers, the first generation making possible

  18. 77 FR 28669 - Pipeline Safety: Information Collection Activities, Excess Flow Valve Census

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-15

    ...Information Collection Activities, Excess Flow Valve Census AGENCY: Pipeline and Hazardous...Information Collection (IC) on Excess Flow Valves (EFVs). PHMSA will request approval...Information Collection on Excess Flow Valves.'' In 1996, PHMSA's...

  19. Active Flow Control: Instrumentation Automation and Experimental Technique

    NASA Technical Reports Server (NTRS)

    Gimbert, N. Wes

    1995-01-01

    In investigating the potential of a new actuator for use in an active flow control system, several objectives had to be accomplished, the largest of which was the experimental setup. The work was conducted at the NASA Langley 20x28 Shear Flow Control Tunnel. The actuator named Thunder, is a high deflection piezo device recently developed at Langley Research Center. This research involved setting up the instrumentation, the lighting, the smoke, and the recording devices. The instrumentation was automated by means of a Power Macintosh running LabVIEW, a graphical instrumentation package developed by National Instruments. Routines were written to allow the tunnel conditions to be determined at a given instant at the push of a button. This included determination of tunnel pressures, speed, density, temperature, and viscosity. Other aspects of the experimental equipment included the set up of a CCD video camera with a video frame grabber, monitor, and VCR to capture the motion. A strobe light was used to highlight the smoke that was used to visualize the flow. Additional effort was put into creating a scale drawing of another tunnel on site and a limited literature search in the area of active flow control.

  20. Slow Magnetosonic Waves and Fast Flows in Active Region Loops

    NASA Technical Reports Server (NTRS)

    Ofman, L.; Wang, T. J.; Davila, J. M.

    2012-01-01

    Recent extreme ultraviolet spectroscopic observations indicate that slow magnetosonic waves are present in active region (AR) loops. Some of the spectral data were also interpreted as evidence of fast (approx 100-300 km/s) quasiperiodic flows. We have performed three-dimensional magnetohydrodynamic (3D MHD) modeling of a bipolar AR that contains impulsively generated waves and flows in coronal loops. The model AR is initiated with a dipole magnetic field and gravitationally stratified density, with an upflow-driven steadily or periodically in localized regions at the footpoints of magnetic loops. The resulting flows along the magnetic field lines of the AR produce higher density loops compared to the surrounding plasma by injection of material into the flux tubes and the establishment of siphon flow.We find that the impulsive onset of flows with subsonic speeds result in the excitation of damped slow magnetosonic waves that propagate along the loops and coupled nonlinearly driven fast-mode waves. The phase speed of the slow magnetosonic waves is close to the coronal sound speed. When the amplitude of the driving pulses is increased we find that slow shock-like wave trains are produced. When the upflows are driven periodically, undamped oscillations are produced with periods determined by the periodicity of the upflows. Based on the results of the 3D MHD model we suggest that the observed slow magnetosonic waves and persistent upflows may be produced by the same impulsive events at the bases of ARs.

  1. Energy Activities for the Primary Classroom. Revised.

    ERIC Educational Resources Information Center

    Tierney, Blue, Comp.

    An energy education program at the primary level should help students to understand the nature and importance of energy, consider different energy sources, learn about energy conservation, prepare for energy related careers, and become energy conscious in other career fields. The activities charts, readings, and experiments provided in this…

  2. The Redox Flow System for solar photovoltaic energy storage

    Microsoft Academic Search

    P. Odonnell; R. F. Gahn; W. Pfeiffer

    1976-01-01

    The interfacing of a Solar Photovoltaic System and a Redox Flow System for storage was workable. The Redox Flow System, which utilizes the oxidation-reduction capability of two redox couples, in this case iron and titanium, for its storage capacity, gave a relatively constant output regardless of solar activity so that a load could be run continually day and night utilizing

  3. Conformal curvature flows: From phase transitions to active vision

    Microsoft Academic Search

    Satyanad Kichenassamy; Arun Kumar; Peter Olver; Allen Tannenbaum; Anthony Yezzi

    1996-01-01

    In this paper, we analyze geometric active contour models from a curve evolution point of view and propose some modifications based on gradient flows relative to certain new feature-based Riemannian metrics. This leads to a novel edge-detection paradigm in which the feature of interest may be considered to lie at the bottom of a potential well. Thus an edge-seeking curve

  4. Conformal Curvature Flows: From Phase Transitions to Active Vision

    Microsoft Academic Search

    Satyanad Kichenassamy; Arun Kumar

    1995-01-01

    In this paper, we analyze geometric active contour models from a curve evolutionpoint of view and propose some modifications based on gradient flows relative to certainnew feature-based Riemannian metrics. This leads to a novel edge-detection paradigmin which the feature of interest may be considered to lie at the bottom of a potentialwell. Thus an edge-seeking curve is attracted very naturally

  5. Boeing active flow control system (BAFCS)-II

    NASA Astrophysics Data System (ADS)

    Jacot, A. Dean; Calkins, Frederick T.; Mabe, Jim H.

    2001-06-01

    The Boeing Active Flow Control (AFC) System (BAFCS) is a DARPA sponsored program to develop AFC technology to achieve a significant increase in payload for rotorcraft applications such as the V-22 tiltrotor vehicle. The program includes Computational Fluid Dynamics (CFD) analysis, wind tunnel testing and development of smart material based AFC actuators. This paper will provide an overview of the program, concentrating on the development of the AFC actuators, and is an update of reference 1,2.

  6. The Role of Water Vapour in Earth's Energy Flows

    NASA Astrophysics Data System (ADS)

    Allan, Richard P.

    2012-07-01

    Water vapour modulates energy flows in Earth's climate system through transfer of latent heat by evaporation and condensation and by modifying the flows of radiative energy both in the longwave and shortwave portions of the electromagnetic spectrum. This article summarizes the role of water vapour in Earth's energy flows with particular emphasis on (1) the powerful thermodynamic constraint of the Clausius Clapeyron equation, (2) dynamical controls on humidity above the boundary layer (or free-troposphere), (3) uncertainty in continuum absorption in the relatively transparent "window" regions of the radiative spectrum and (4) implications for changes in the atmospheric hydrological cycle.

  7. Gaseous micro-emboli activity during cardiopulmonary bypass in adults: pulsatile flow versus nonpulsatile flow.

    PubMed

    Dodonov, Mikhail; Milano, Aldo; Onorati, Francesco; Dal Corso, Bruno; Menon, Tiziano; Ferrarini, Daniele; Tessari, Maddalena; Faggian, Giuseppe; Mazzucco, Alessandro

    2013-04-01

    Cardiopulmonary bypass (CPB) has a risk of cerebral injury, with an important role of gaseous micro-emboli (GME) coming from the CPB circuit. Pulsatile perfusion is supposed to perform specific conditions for supplementary GME activity. We aimed to determine whether pulsatile CPB augments production and delivery of GME and evaluate the role of different events in GME activity during either type of perfusion. Twenty-four patients who underwent on-pump coronary artery bypass grafting surgery at the University of Verona were divided equally into two groups-pulsatile perfusion (PP) group and nonpulsatile perfusion (NP) group. The circuit included a JostraHL-20 roller pump set in pulsatile or nonpulsatile mode, an open Sorin Synthesis membrane oxygenator with integrated screen-type arterial filter, and phosphorylcholine-coated tubes. Hemodynamic flow evaluation was performed in terms of energy equivalent pressure and surplus hemodynamic energy (SHE). GME were counted by means of a GAMPT BCC200 bubble counter (GAMPT, Zappendorf, Germany) with two probes placed at postpump and postarterial filter positions. Results were evaluated in terms of GME number, GME volume, number of over-ranged GME from both probes, and series of filtering indexes. In PP mode, the pump produced and delivered along the circuit significantly higher amounts of SHE than in NP mode. At the venous postpump site, GME number was significantly higher during PP but no difference was found in terms of GME volume or number of over-ranged bubbles. No significant difference in GME number, GME volume, or number of over-ranges was found at the postarterial filter site. Filtering indexes were similar between the two groups. Neither type of perfusion was shown to contribute to excessive GME production during the most important perfusionist manipulation. Pulsatility leads to GME increment by splitting and size diminishing of the existing bubbles but not by additional gas production. PP augmented GME number at the venous postpump site, while mean volume remained comparable with NP. Sorin Synthesis oxygenator showed high efficacy in GME removal during either type of perfusion. Supplementary GME production and delivery during typical perfusionist manipulations did not depend on perfusion type. PMID:23489040

  8. Fluid flow and heat convection studies for actively cooled airframes

    NASA Astrophysics Data System (ADS)

    Mills, A. F.

    1992-10-01

    The work done during the progress report period from May-October 1992 is summarized. The effect of wall thermal boundary conditions on flows over a step or rib when repeated rib roughness is used for heating augmentation is examined. In numerical investigations of various such laminar and turbulent flows, the local heat transfer coefficients on a forward-facing step or on a rib were found to be very sensitive to the wall thermal boundary condition. For the computation of constant property laminar flow, the wall thermal boundary conditions were either a uniform heat flux or a uniform temperature. Results (Nusselt number and isotherms) of the studies are included. The second part of the work consisted of using PHOENICS to solve the conjugate heat transfer problem of flow over a rib in channel. Finally, the algebraic stress model in the TEAM (Turbulent Elliptic Algorithm-Manchester) code was tested for jet impingement flow, but there needs to be an addition of the energy equation to the code.

  9. Radiant energy receiver having improved coolant flow control means

    DOEpatents

    Hinterberger, H.

    1980-10-29

    An improved coolant flow control for use in radiant energy receivers of the type having parallel flow paths is disclosed. A coolant performs as a temperature dependent valve means, increasing flow in the warmer flow paths of the receiver, and impeding flow in the cooler paths of the receiver. The coolant has a negative temperature coefficient of viscosity which is high enough such that only an insignificant flow through the receiver is experienced at the minimum operating temperature of the receiver, and such that a maximum flow is experienced at the maximum operating temperature of the receiver. The valving is accomplished by changes in viscosity of the coolant in response to the coolant being heated and cooled. No remotely operated valves, comparators or the like are needed.

  10. Entrainment of coarse particles in turbulent flows: An energy approach

    NASA Astrophysics Data System (ADS)

    Valyrakis, Manousos; Diplas, Panayiotis; Dancey, Clint L.

    2013-03-01

    The entrainment of coarse sediment particles under the action of fluctuating hydrodynamic forces is investigated from an energy perspective. It is demonstrated that the entrainment of a grain resting on the channel boundary is possible when the instantaneous flow power transferred to it exceeds a critical level. Its complete removal from the bed matrix occurs only if the impinging flow events supply sufficient mechanical energy. The energy-based criterion is formulated theoretically for entrainment of individual spherical particles in both saltation and rolling modes. Out of the wide range of flow events that can perform mechanical work on a coarse grain, only those with sufficient power and duration or equivalent energy density and characteristic length scale may accomplish its complete dislodgement. The instantaneous velocity upstream of a mobile particle is synchronously recorded with its position, enabling the identification of the flow events responsible for grain entrainment by rolling at near incipient motion flow conditions. For each of the entrainment events, the energy transfer coefficient defined as the ratio of the mechanical work performed on the particle to the mean energy of the flow event responsible for its dislodgement obtains values ranging from 0.04 to 0.10. At the examined low-mobility flow conditions, the majority (about 80%) of the energetic structures leading to complete particle entrainment have a characteristic length of about two to four particle diameters.

  11. Active Flow Control on Bidirectional Rotors for Tidal MHK Applications

    SciTech Connect

    Shiu, Henry [Research Engineer; van Dam, Cornelis P. [Professor

    2013-08-22

    A marine and hydrokinetic (MHK) tidal turbine extracts energy from tidal currents, providing clean, sustainable electricity generation. In general, all MHK conversion technologies are confronted with significant operational hurdles, resulting in both increased capital and operations and maintenance (O&M) costs. To counter these high costs while maintaining reliability, MHK turbine designs can be simplified. Prior study found that a tidal turbine could be cost-effectively simplified by removing blade pitch and rotor/nacelle yaw. Its rotor would run in one direction during ebb and then reverse direction when the current switched to flood. We dubbed such a turbine a bidirectional rotor tidal turbine (BRTT). The bidirectional hydrofoils of a BRTT are less efficient than conventional hydrofoils and capture less energy, but the elimination of the pitch and yaw systems were estimated to reduce levelized cost of energy by 7.8%-9.6%. In this study, we investigated two mechanisms for recapturing some of the performance shortfall of the BRTT. First, we developed a novel set of hydrofoils, designated the yy series, for BRTT application. Second, we investigated the use of active flow control via microtabs. Microtabs are small deployable/retractable tabs, typically located near the leading or trailing edge of an air/hydrofoil with height on the order of the boundary layer thickness (1% - 2% of chord). They deploy approximately perpendicularly to the foil surface and, like gurney flaps and plain flaps, globally affect the aerodynamics of the airfoil. By strategically placing microtabs and selectively deploying them based on the direction of the inflow, performance of a BRTT rotor can be improved while retaining bidirectional operation. The yy foils were computationally designed and analyzed. They exhibited better performance than the baseline bidirectional foil, the ellipse. For example, the yyb07cn-180 had 14.7% higher (l/d)max than an ellipse of equal thickness. The yyb07cn family also had higher c{sub p,min} than equivalently thick ellipses, indicating less susceptibility to cavitation. Microtabs applied on yy foils demonstrated improved energy capture. A series of variable speed and constant speed rotors were developed with the yyb07cn family of hydrofoils. The constant speed yyb07cn rotor (yy-B02-Rcs,opt) captured 0.45% more energy than the equivalent rotor with ellipses (e-B02-Rcs,opt). With microtabs deployed (yy?t-B02-Rcs,opt), the energy capture increase over the rotor with ellipses was 1.05%. Note, however, that microtabs must be applied judiciously to bidirectional foils. On the 18% thick ellipse, performance decreased with the addition of microtabs. Details of hydrofoil performance, microtab sizing and positioning, rotor configurations, and revenue impacts are presented herein.

  12. Anisotropic energy flow and allosteric ligand binding in albumin

    NASA Astrophysics Data System (ADS)

    Li, Guifeng; Magana, Donny; Dyer, R. Brian

    2014-01-01

    Allosteric interactions in proteins generally involve propagation of local structural changes through the protein to a remote site. Anisotropic energy transport is thought to couple the remote sites, but the nature of this process is poorly understood. Here, we report the relationship between energy flow through the structure of bovine serum albumin and allosteric interactions between remote ligand binding sites of the protein. Ultrafast infrared spectroscopy is used to probe the flow of energy through the protein backbone following excitation of a heater dye, a metalloporphyrin or malachite green, bound to different binding sites in the protein. We observe ballistic and anisotropic energy flow through the protein structure following input of thermal energy into the flexible ligand binding sites, without local heating of the rigid helix bundles that connect these sites. This efficient energy transport mechanism enables the allosteric propagation of binding energy through the connecting helix structures.

  13. Anisotropic energy flow and allosteric ligand binding in albumin

    PubMed Central

    Li, Guifeng; Magana, Donny; Dyer, R. Brian

    2014-01-01

    Allosteric interactions in proteins generally involve propagation of local structural changes through the protein to a remote site. Anisotropic energy transport is thought to couple the remote sites, but the nature of this process is poorly understood. Here, we report the relationship between energy flow through the structure of bovine serum albumin and allosteric interactions between remote ligand binding sites of the protein. Ultrafast infrared spectroscopy is used to probe the flow of energy through the protein backbone following excitation of a heater dye, a metalloporphyrin or malachite green, bound to different binding sites in the protein. We observe ballistic and anisotropic energy flow through the protein structure following input of thermal energy into the flexible ligand binding sites, without local heating of the rigid helix bundles that connect these sites. This efficient energy transport mechanism enables the allosteric propagation of binding energy through the connecting helix structures. PMID:24445265

  14. Energy Storage. Teachers Guide. Science Activities in Energy.

    ERIC Educational Resources Information Center

    Jacobs, Mary Lynn, Ed.

    Included in this science activities energy package for students in grades 4-10 are 12 activities related to energy storage. Each activity is outlined on the front and back of a single sheet and is introduced by a key question. Most of the activities can be completed in the classroom with materials readily available in any community. Among the…

  15. Analysis of changing hidden energy flow in Vietnam

    Microsoft Academic Search

    Nguyen Thi Anh Tuyet; Keiichi N. Ishihara

    2006-01-01

    The energy consumption in production process is changing especially in developing countries by substituting technology. Input–output analysis for energy flows has been developing and is one of the best solutions for investigating macroscopic exchanges of both economy and energy. Since each element in the Leontief inverse contains both direct and indirect effects of any change in final demand, to separate

  16. Ambient wind energy harvesting using cross-flow fluttering

    Microsoft Academic Search

    Shuguang Li; Jianping Yuan; Hod Lipson

    2011-01-01

    In this experimental study, we propose and test a bioinspired piezo-leaf architecture which converts wind energy into electrical energy by wind-induced fluttering motion. While conventional fluttering devices are arranged in parallel with the flow direction, here we explore a dangling cross-flow stalk arrangement. This architecture amplifies the vibration by an order of magnitude, making it appropriate for low-cost organic piezomaterials.

  17. Energy Conservation Activity Packet, K-2.

    ERIC Educational Resources Information Center

    Bakke, Ruth

    This book was developed in response to the concern for energy conservation. It contains activities that stress an energy conservation ethic and includes many values clarification activities for grades K-2. The teacher is provided with some background information on energy, an extensive teacher's annotated bibliography, and a list of resources. The…

  18. Numerical modeling of energy related flows. Final report

    SciTech Connect

    Berger, B.S.

    1984-12-05

    After a brief review of the theoretical and computational results obtained for various kinds of fluid flows, several papers are appended covering: viscous, incompressible, time-dependent fluid flow around a circular cylinder; asymptotic approximation and perturbation stream functions for viscous flow calculations; velocity and vorticity correlations; a finite difference approximation for the mean vorticity and covariance equation of the MVC closure; the motion of a circular cylinder for a viscous, incompressible crossflow; the symmetry of the Eulerian correlation function; the vibration of a circular cylinder in a crossflow; energy and vorticity dynamics in decaying isotropic turbulence; wall turbulence at the k-epsilon closure; a method for computing three-dimensional turbulent flows; and balance of turbulent energy in the linear wall region of channel flow. (LEW)

  19. Two-phase flow in a chemically active porous medium

    E-print Network

    Alexandre Darmon; Michael Benzaquen; Thomas Salez; Olivier Dauchot

    2014-11-20

    We study the problem of the transformation of a given reactant species into an immiscible product species, as they flow through a chemically active porous medium. We derive the equation governing the evolution of the volume fraction of the species -- in a one-dimensional macroscopic description --, identify the relevant dimensionless numbers, and provide simple models for capillary pressure and relative permeabilities, which are quantities of crucial importance when tackling multiphase flows in porous media. We set the domain of validity of our models and discuss the importance of viscous coupling terms in the extended Darcy's law. We investigate numerically the steady regime and demonstrate that the spatial transformation rate of the species along the reactor is non-monotonous, as testified by the existence of an inflection point in the volume fraction profiles. We obtain the scaling of the location of this inflection point with the dimensionless lengths of the problem. Eventually, we provide key elements for optimization of the reactor.

  20. Spontaneous flow states in active nematics: a unified picture

    E-print Network

    S. A. Edwards; J. M. Yeomans

    2008-11-21

    Continuum hydrodynamic models of active liquid crystals have been used to describe dynamic self-organising systems such as bacterial swarms and cytoskeletal gels. A key prediction of such models is the existence of self-stabilising kink states that spontaneously generate fluid flow in quasi-one dimensional channels. Using simple stability arguments and numerical calculations we extend previous studies to give a complete characterisation of the phase space for both contractile and extensile particles (ie pullers and pushers) moving in a narrow channel as a function of their flow alignment properties and initial orientation. This gives a framework for unifying many of the results in the literature. We describe the response of the kink states to an imposed shear, and investigate how allowing the system to be polar modifies its dynamical behaviour.

  1. Stocks, Flows, and Prospects of Energy

    SciTech Connect

    Loschel, Andrea [The Centre for European Economic Research (ZEW); Johnston, John [Exxon Mobil Research and Engineering; Delucchi, Mark A [University of California, Davis; Demayo, Trevor N [Chevron, USA; Gautier, Donald L [U.S. Geological Survey; Greene, David L [ORNL; Ogden, Joan [University of California, Davis; Rayner, Steve [University of Oxford; Worrell, Ernst [Ecofys

    2009-01-01

    Analyses of future energy systems have typically focused on energy suffi ciency and climate change issues. While the potential supply of energy services will probably not constrain us in the immediate future, there are limits imposed on the energy system by climate change considerations, which, in turn, are inextricably bound up with land, water, and nonrenewable mineral resources issues. These could pose constraints to energy systems that may not have been fully accounted for in current analyses. There is a pressing lack of knowledge on the boundaries that will impact a sustainable energy system. A more integrated view of energy sustainability is necessary to ensure the well-being of current and future generations. This chapter proposes a set of measures related to sustainability within the context of selected energy scenarios and develops a methodology to define and measure relevant quantities and important links to other resource areas.

  2. Stocks, Flows, and Prospects of Energy

    SciTech Connect

    Loschel, Andrea [The Centre for European Economic Research (ZEW); Johnston, John [Exxon Mobil Research and Engineering; Delucchi, Mark A [University of California, Davis; Demayo, Trevor N [Chevron, USA; Gautier, Donald L [U.S. Geological Survey; Greene, David L [ORNL; Ogden, Joan [University of California, Davis; Rayner, Steve [University of Oxford; Worrell, Ernst [Ecofys

    2010-01-01

    Analyses of future energy systems have typically focused on energy sufficiency and climate change issues. While the potential supply of energy services will probably not constrain us in the immediate future, there are limits imposed on the energy system by climate change considerations, which, in turn, are inextricably bound up with land, water, and nonrenewable mineral resources issues. These could pose constraints to energy systems that may not have been fully accounted for in current analyses. There is a pressing lack of knowledge on the boundaries that will impact a sustainable energy system. A more integrated view of energy sustainability is necessary to ensure the well-being of current and future generations. This chapter proposes a set of measures related to sustainability within the context of selected energy scenarios and develops a methodology to define and measure relevant quantities and important links to other resource areas.

  3. A new energy transfer model for turbulent free shear flow

    NASA Technical Reports Server (NTRS)

    Liou, William W.-W.

    1992-01-01

    A new model for the energy transfer mechanism in the large-scale turbulent kinetic energy equation is proposed. An estimate of the characteristic length scale of the energy containing large structures is obtained from the wavelength associated with the structures predicted by a weakly nonlinear analysis for turbulent free shear flows. With the inclusion of the proposed energy transfer model, the weakly nonlinear wave models for the turbulent large-scale structures are self-contained and are likely to be independent flow geometries. The model is tested against a plane mixing layer. Reasonably good agreement is achieved. Finally, it is shown by using the Liapunov function method, the balance between the production and the drainage of the kinetic energy of the turbulent large-scale structures is asymptotically stable as their amplitude saturates. The saturation of the wave amplitude provides an alternative indicator for flow self-similarity.

  4. Snapshot of Active Flow Control Research at NASA Langley

    NASA Technical Reports Server (NTRS)

    Washburn, A. E.; Gorton, S. Althoff; Anders, S. G.

    2002-01-01

    NASA Langley is aggressively investigating the potential advantages of active flow control as opposed to more traditional aerodynamic techniques. Many of these techniques will be blended with advanced materials and structures to further enhance payoff. Therefore a multi-disciplinary approach to technology development is being attempted that includes researchers from the more historical disciplines of fluid mechanics. acoustics, material science, structural mechanics, and control theory. The overall goals of the topics presented are focused on advancing the state of knowledge and understanding of controllable fundamental mechanisms in fluids rather than on specific engineering problems. An organizational view of current research activities at NASA Langley in active flow control as supported by several programs such as the Morphing Project under Breakthrough Vehicle Technologies Program (BVT). the Ultra-Efficient Engine Technology Program (UEET), and the 21st Century Aircraft Technology Program (TCAT) is presented. On-center research as well as NASA Langley funded contracts and grants are discussed at a relatively high level. The products of this research, as part of the fundamental NASA R and D (research and development) program. will be demonstrated as either bench-top experiments, wind-tunnel investigations, or in flight tests. Later they will be transferred to more applied research programs within NASA, DOD (Department of Defense), and U.S. industry.

  5. Active flow control for a blunt trailing edge profiled body

    NASA Astrophysics Data System (ADS)

    Naghib Lahouti, Arash

    Flow in the wake of nominally two-dimensional bluff bodies is dominated by vortex shedding, beyond a very small threshold Reynolds number. Vortex shedding poses challenges in the design of structures, due to its adverse effects such as cyclic aerodynamic loads and fatigue. The wake vortices are often accompanied by large- and small-scale secondary instabilities, which manifest as dislocations in the primary wake vortices, and/or pairs of counter-rotating streamwise vortices, depending on the dominant instability mode(s), which in turn depends on the profile geometry and Reynolds number. The secondary instabilities interact with the wake vortices through several mechanisms. Therefore, manipulation of the secondary instabilities can be used as a means to alter the wake vortices, in order to reduce their adverse effects. In the present study, flow in the wake of a blunt trailing edge profiled body, composed of an elliptical leading edge and a rectangular trailing edge, has been studied at Reynolds numbers ranging from Re(d) = 500 to 2150 where d is thickness of the body, to identify the secondary instabilities. Various tools, including numerical simulations, Laser Induced Fluorescence (LIF), and Particle Image Velocimetry (PIV) have been used for this study. Proper Orthogonal Decomposition (POD) has been applied to analyze the velocity field data. The results indicate the existence of small-scale instabilities with a spanwise wavelength of 2.0d to 2.5d in the near wake. The mechanism of the instability is similar to the Mode-A instability of a circular cylinder; however, it displays features that are specific to the blunt trailing edge profiled body. An active three-dimensional flow control mechanism based on the small-scale instabilities has been designed and evaluated. The mechanism comprises a series of trailing edge injection ports, with a spanwise spacing equal to the wavelength of the small-scale instabilities. Following preliminary evaluation of the control mechanism through numerical simulations, and experimental study of the effect of injection flow rate, extensive PIV experiments have been conducted to investigate the effectiveness of the flow control mechanism, and its effects on the wake flow structure, at Reynolds numbers ranging from Re(d ) = 700 to 1980. Measurements have been carried out at multiple spanwise locations, to establish a comprehensive image of the effect of the flow control mechanism on parameters such as drag force, wake width, and formation length. POD analysis and frequency spectrums are used to describe the process by which the mechanism affects the wake parameters and drag force. The results indicate that the flow control mechanism is able to reduce drag force by 10%. It is also shown that the best effectiveness in terms of suppression of the drag component resulting from velocity fluctuations is achieved when the flow control actuation wavelength closely matches the wavelength of the small-scale instabilities. KEYWORDS: Blunt Trailing Edge Profiled Body, Vortex Shedding, Wake Instability, Streamwise Vortex, Flow Control, Drag Reduction, Particle Image Velocimetry (PIV), Laser Induced Fluorescence (LIF), Flow Visualization, Numerical Simulation

  6. K.E.E.P. - Kentucky's Energy Education Program Activities for the Classroom, 7-12.

    ERIC Educational Resources Information Center

    Theiss, Nancy Stearns, Ed.; And Others

    Seventy-four multidisciplinary activities for grades seven through twelve are contained in this revised edition of energy education lessons for Kentucky students. Section I helps students understand energy and the current crisis by studying laws which govern energy flow and using examples of how these laws illustrate stable energy utilization…

  7. Groundwater Flow Demonstration Model Activities for Grades 6-12

    NSDL National Science Digital Library

    Kitt Farrell-Poe

    This set of activities is designed to use a demonstration model available through the Uath County Cooperative Extension Services or from Project WET. They demonstrate such concepts as aquifers, groundwater flow, water table, the relationship between groundwater and surface water, recharge, and others. A glossary and standards correlations to the Utah Core Curriculum for Science are included. The physical model can be obtained through the Utah County Cooperative Extension Service, the Utah Water Resources Education Program, or for sale from Project WET (Water Education for Teachers).

  8. Boeing active flow control system (BAFCS)-III

    NASA Astrophysics Data System (ADS)

    Jacot, A. Dean; Calkins, Frederick T.; Smith, Josef

    2002-07-01

    The Boeing Active Flow Control (AFC) System is a DARPA sponsored program to develop AFC technology to achieve a significant increase in payload and/or range for rotorcraft applications such as the V-22 tiltrotor vehicle. The program includes Computational Fluid Dynamics analysis, 0.1 scale wind tunnel and 3D testing and development of smart material based AFC actuators. This paper will provide an overview of the program, concentrating on the development and testing of the AFC actuators, and is an update of references to 1 to 3.

  9. Energy Flow Analysis of Photoactive Yellow Protein

    NASA Astrophysics Data System (ADS)

    Ishikura, Takakazu; Kawaguchi, Kazutomo; Watanabe, Hiroshi; Yamato, Takahisa

    2006-03-01

    The signal transduction of photosensory receptors is intimately related to the energy relaxation associated with the relevant functional motion. To understand this energy conversion process, it is useful to analyse the energy flux vector field in a polypeptide chain matrix. Recently, we developed a new formalism for energy flux, JAB, between two different sites A and B in a protein. Flexibility is one of the attractive points of this method, namely, sites A/B can be consisted of an atom or any groups of atoms. In addition, huge computation resource is not required for this method. Since this method is based on the linear response theory, the energy flux, JAB, can be obtained from a classical molecular dynamics simulation trajectory. We can define energy conductivity between the sites A and B in terms of the time-correlation function of JAB. This quantity corresponds to the transport coefficient of heat and potential energy, representing the strength of the direct energetic coupling between the two sites. We applied this method to a photosensory receptor, photoactive yellow protein (PYP). We calculated the energy conductivity between the chromophore and the surrounding amino acid residues, Tyr42, Glu46, Thr50, Arg52, and Tyr98. As a result, we observed the values of energy conductivity decreased in this order. We will discuss the possibility of finding energy transfer pathway in PYP with this method.

  10. Flow of energy in the outer retina in darkness and in light

    PubMed Central

    Linton, Jonathan D.; Holzhausen, Lars C.; Babai, Norbert; Song, Hongman; Miyagishima, Kiyoharu J.; Stearns, George W.; Lindsay, Ken; Wei, Junhua; Chertov, Andrei O.; Peters, Theo A.; Caffe, Romeo; Pluk, Helma; Seeliger, Mathias W.; Tanimoto, Naoyuki; Fong, Kimberly; Bolton, Laura; Kuok, Denise L. T.; Sweet, Ian R.; Bartoletti, Theodore M.; Radu, Roxana A.; Travis, Gabriel H.; Zagotta, Willam N.; Townes-Anderson, Ellen; Parker, Ed; Van der Zee, Catharina E. E. M.; Sampath, Alapakkam P.; Sokolov, Maxim; Thoreson, Wallace B.; Hurley, James B.

    2010-01-01

    Structural features of neurons create challenges for effective production and distribution of essential metabolic energy. We investigated how metabolic energy is distributed between cellular compartments in photoreceptors. In avascular retinas, aerobic production of energy occurs only in mitochondria that are located centrally within the photoreceptor. Our findings indicate that metabolic energy flows from these central mitochondria as phosphocreatine toward the photoreceptor’s synaptic terminal in darkness. In light, it flows in the opposite direction as ATP toward the outer segment. Consistent with this model, inhibition of creatine kinase in avascular retinas blocks synaptic transmission without influencing outer segment activity. Our findings also reveal how vascularization of neuronal tissue can influence the strategies neurons use for energy management. In vascularized retinas, mitochondria in the synaptic terminals of photoreceptors make neurotransmission less dependent on creatine kinase. Thus, vasculature of the tissue and the intracellular distribution of mitochondria can play key roles in setting the strategy for energy distribution in neurons. PMID:20445106

  11. Structure of urban movements: polycentric activity and entangled hierarchical flows.

    PubMed

    Roth, Camille; Kang, Soong Moon; Batty, Michael; Barthélemy, Marc

    2011-01-01

    The spatial arrangement of urban hubs and centers and how individuals interact with these centers is a crucial problem with many applications ranging from urban planning to epidemiology. We utilize here in an unprecedented manner the large scale, real-time 'Oyster' card database of individual person movements in the London subway to reveal the structure and organization of the city. We show that patterns of intraurban movement are strongly heterogeneous in terms of volume, but not in terms of distance travelled, and that there is a polycentric structure composed of large flows organized around a limited number of activity centers. For smaller flows, the pattern of connections becomes richer and more complex and is not strictly hierarchical since it mixes different levels consisting of different orders of magnitude. This new understanding can shed light on the impact of new urban projects on the evolution of the polycentric configuration of a city and the dense structure of its centers and it provides an initial approach to modeling flows in an urban system. PMID:21249210

  12. Structure of Urban Movements: Polycentric Activity and Entangled Hierarchical Flows

    PubMed Central

    Roth, Camille; Kang, Soong Moon; Batty, Michael; Barthélemy, Marc

    2011-01-01

    The spatial arrangement of urban hubs and centers and how individuals interact with these centers is a crucial problem with many applications ranging from urban planning to epidemiology. We utilize here in an unprecedented manner the large scale, real-time ‘Oyster’ card database of individual person movements in the London subway to reveal the structure and organization of the city. We show that patterns of intraurban movement are strongly heterogeneous in terms of volume, but not in terms of distance travelled, and that there is a polycentric structure composed of large flows organized around a limited number of activity centers. For smaller flows, the pattern of connections becomes richer and more complex and is not strictly hierarchical since it mixes different levels consisting of different orders of magnitude. This new understanding can shed light on the impact of new urban projects on the evolution of the polycentric configuration of a city and the dense structure of its centers and it provides an initial approach to modeling flows in an urban system. PMID:21249210

  13. Energy momentum flows for the massive vector field

    E-print Network

    George Horton; Chris Dewdney

    2006-09-26

    We present a causal trajectory interpretation for the massive vector field, based on the flows of rest energy and a conserved density defined using the time-like eigenvectors and eigenvalues of the stress-energy-momentum tensor. This work extends our previous work which used a similar procedure for the scalar field. The massive, spin-one, complex vector field is discussed in detail and solutions are classified using the Pauli-Lubanski spin vector. The flows of energy-momentum are illustrated in a simple example of standing waves in a plane.

  14. Flow cytometric analysis of crayfish haemocytes activated by lipopolysaccharides

    USGS Publications Warehouse

    Cardenas, W.; Dankert, J.R.; Jenkins, J.A.

    2004-01-01

    Lipopolysaccharides (LPS) from Gram-negative bacteria are strong stimulators of white river crayfish, Procambarus zonangulus, haemocytes in vitro. Following haemocyte treatment with LPS and with LPS from rough mutant R5 (LPS Rc) from Salmonella minnesota, flow cytometric analysis revealed a conspicuous and reproducible decrease in cell size as compared to control haemocytes. These LPS molecules also caused a reduction in haemocyte viability as assessed by flow cytometry with the fluorescent dyes calcein-AM and ethidium homodimer. The onset of cell size reduction was gradual and occurred prior to cell death. Haemocytes treated with LPS from S. minnesota without the Lipid A moiety (detoxified LPS) decreased in size without a reduction of viability. The action of LPS on crayfish haemocytes appeared to be related to the activation of the prophenoloxidase system because phenoloxidase (PO)-specific activity in the supernatants from control and detoxified LPS-treated cells was significantly lower than that from LPS and LPS-Rc treated cells (P < 0.05). Furthermore, addition of trypsin inhibitor to the LPS treatments caused noticeable delays in cell size and viability changes. These patterns of cellular activation by LPS formulations indicated that crayfish haemocytes react differently to the polysaccharide and lipid A moieties of LPS, where lipid A is cytotoxic and the polysaccharide portion is stimulatory. These effects concur with the general pattern of mammalian cell activation by LPS, thereby indicting commone innate immune recognition mechanisms to bacterial antigens between cells from mammals and invertebrates. These definitive molecular approaches used to verify and identify mechanisms of invertbrate haemocyte responses to LPS could be applied with other glycoconjugates, soluble mediators, or xenobiotic compounds.

  15. Managing talent flow. 2006 Energy and Resources

    E-print Network

    and market growth in mining, utilities, oil and gas have been relatively stagnant, prompting many young such as the energy sector, the result is a chronic shortage of qualified workers. And the problem is only going of 332,000 workers1 . The impending shortage has already caused concern among energy sector organizations

  16. An integral turbulent kinetic energy analysis of free shear flows

    NASA Technical Reports Server (NTRS)

    Peters, C. E.; Phares, W. J.

    1973-01-01

    Mixing of coaxial streams is analyzed by application of integral techniques. An integrated turbulent kinetic energy (TKE) equation is solved simultaneously with the integral equations for the mean flow. Normalized TKE profile shapes are obtained from incompressible jet and shear layer experiments and are assumed to be applicable to all free turbulent flows. The shear stress at the midpoint of the mixing zone is assumed to be directly proportional to the local TKE, and dissipation is treated with a generalization of the model developed for isotropic turbulence. Although the analysis was developed for ducted flows, constant-pressure flows were approximated with the duct much larger than the jet. The axisymmetric flows under consideration were predicted with reasonable accuracy. Fairly good results were also obtained for the fully developed two-dimensional shear layers, which were computed as thin layers at the boundary of a large circular jet.

  17. Mechanical energy and power flow of the upper extremity in manual wheelchair propulsion

    Microsoft Academic Search

    Lan-Yuen Guo; Fong-Chin Su; Hong-Wen Wu

    2003-01-01

    Objective. To investigate the characteristics of mechanical energy and power flow of the upper limb during wheelchair propulsion. Design. Mechanical energy and power flow of segments were calculated. Background. Very few studies have taken into account the mechanical energy and power flow of the musculoskeletal system during wheelchair propulsion. Mechanical energy and power flow have proven to be useful tools

  18. Distributed Power Flow Control: Distributed Power Flow Control using Smart Wires for Energy Routing

    SciTech Connect

    None

    2012-04-24

    GENI Project: Smart Wire Grid is developing a solution for controlling power flow within the electric grid to better manage unused and overall transmission capacity. The 300,000 miles of high-voltage transmission line in the U.S. today are congested and inefficient, with only around 50% of all transmission capacity utilized at any given time. Increased consumer demand should be met in part with more efficient and an economical power flow. Smart Wire Grid’s devices clamp onto existing transmission lines and control the flow of power within—much like how internet routers help allocate bandwidth throughout the web. Smart wires could support greater use of renewable energy by providing more consistent control over how that energy is routed within the grid on a real-time basis. This would lessen the concerns surrounding the grid’s inability to effectively store intermittent energy from renewables for later use.

  19. Gradient Vector Flow Fast Geodesic Active Contours Nikos Paragios Olivier Mellina-Gottardo

    E-print Network

    Paragios, Nikos

    Gradient Vector Flow Fast Geodesic Active Contours Nikos Paragios Olivier Mellina flow for boundary extraction. The proposed framework is inspired by the geodesic active contour model to a spatial diffusion of the boundary informa- tion. According to the proposed flow, the traditional bound

  20. Magnetotail Flow Bursts: Association to Global Magnetospheric Circulation, Relationship to Ionospheric Activity and Direct Evidence for Localization

    NASA Technical Reports Server (NTRS)

    Angelopoulos, V.; Phan, T. D.; Larson, D. E.; Mozer, F. S.; Lin, R. P.; Parks, G. K.; Brittnacher, M. J.; Germany, G. A.; Spann, J. F., Jr.

    1998-01-01

    A series of bursty bulk flow events (BBFs) were observed by GEOTAIL and WIND in the geomagnetotail. IMP8 at the solar wind showed significant energy coupling into the magnetosphere, while the UVI instrument of POALR evidenced significant energy transfer to the ionosphere during two substorms. There was good correlation between BBFs and ionospheric activity observed by UVI even when ground magnetic signatures were absent, suggesting that low ionospheric conductivity at the active sector may be responsible for this observation. During the second substorm no significant flux transport was evidenced past WIND in stark contrast to GEOTAIL and despite the small intersatellite separation ((3.54, 2.88, -0.06) Re). Throughout the intervals studied there were significant differences in the individual flow bursts at the two satellites, even during longitudinally extended ionospheric activations. We conclude that the half-scale-size of transport bearing flow bursts is less than 3 Re.

  1. Physical activity, energy balance and obesity.

    PubMed

    Luís Griera, José; María Manzanares, José; Barbany, Montserrat; Contreras, José; Amigó, Pilar; Salas-Salvadó, Jordi

    2007-10-01

    Obesity appears when energy intake exceeds energy expenditure. The most important variable compound of energy expenditure is physical activity. The global epidemics of obesity seem closely related to reduced physical activity and sedentariness widely increasing nowadays. Once obesity has developed, caloric intake becomes similar to energy expenditure. To lose weight, besides decreasing energy intake, energy expenditure must be increased. The promotion of physical activity is difficult and so the results of treatment of obesity are discouraging for doctors, other health professionals and patients. Proactive efforts from patients and health providers with an intensive feedback between them may be extremely helpful. Nevertheless, more studies are needed to provide better approaches on the role of physical activity for the prevention and treatment of obesity and for long-term weight-loss maintenance. PMID:17903330

  2. Allosteric Ligand Binding and Anisotropic Energy Flow in Albumin

    NASA Astrophysics Data System (ADS)

    Dyer, Brian

    2014-03-01

    Protein allostery usually involves propagation of local structural changes through the protein to a remote site. Coupling of structural changes at remote sites is thought to occur through anisotropic energy transport, but the nature of this process is poorly understood. We have studied the relationship between allosteric interactions of remote ligand binding sites of the protein and energy flow through the structure of bovine serum albumin (BSA). We applied ultrafast infrared spectroscopy to probe the flow of energy through the protein backbone following excitation of a heater dye, a metalloporphyrin or malachite green, bound to different binding sites in the protein. We observe ballistic flow through the protein structure following input of thermal energy into the flexible ligand binding sites. We also observe anisotropic heat flow through the structure, without local heating of the rigid helix bundles that connect these sites. We will discuss the implications of this efficient energy transport mechanism with regard to the allosteric propagation of binding energy through the connecting helix structures.

  3. Energy Flow Models for the Steel Industry 

    E-print Network

    Hyman, B.; Andersen, J. P.

    1998-01-01

    amount of 654x 10 12 Btu in Table 1 to Process Heat. Other Energy Sources Except Net Steam. As discussed in more detail later, this consists mostly of coke oven gas and blast furnace gas, so the entire 460x10 12 Btu is allocated to Process Heat... gas and blast furnace gas as byproduct energy. Thus, we devote the rest of this paper to discussing a calibrated model of the production and utilization of coal, coke, coke oven gas, and blast furnace gas in these two steps. Our first effort...

  4. Elliptic flow and system size dependence of transition energies at intermediate energies

    E-print Network

    Yingxun Zhang; Zhuxia Li

    2006-06-02

    The elliptic flow for $Z\\le2$ particles in heavy ion collisions at energies from several tens to several hundreds MeV per nucleon is investigated by means of transport model,i.e. a new version of the Improved Quantum Molecular Dynamics model (ImQMD05). In this model, a complete Skyrme potential energy density functional is employed. The influence of different effective interactions and medium corrections of nucleon-nucleon cross sections on the elliptic flow are studied. Our results show that a soft nuclear equation of state and incident energy dependent in-medium nucleon-nucleon cross sections are required for describing the excitation function of the elliptic flow at intermediate energies. The size dependence of transition energies for the elliptic flow at intermediate energies is also studied. The system size dependence of transition energies fits a power of system size with a exponent of 0.223.

  5. Relationship between streaming current and activation energy

    Microsoft Academic Search

    S. Watanabe; M. Fujii; K. Tanabe; A. Ohashi; W. Z. Han; M. Benyamina; G. Touchard

    1988-01-01

    When a liquid with good insulating properties flows through a pipe an electrical charge is generated. In the author's previous investigations of charge volume in such cases, the charge was found to depend on the product of (1) the quantity of dissociated ions in the liquid and (2) the quantity of energy required to transfer these ions to the interface

  6. U.S. energy flow -- 1994

    Microsoft Academic Search

    I. Y. Borg; C. K. Briggs

    1995-01-01

    Energy consumption in 1994 increased for the fourth year in a row, reaching an all-time high. It was associated with a robust economy, low inflation, and low unemployment rates. Of the populous states, California lagged substantially behind the national recovery. Consumption in all major end-use sectors reached historic highs. Transmission of electrical power by the utilities increased almost 3%. However,

  7. Sulphur-impregnated flow cathode to enable high-energy-density lithium flow batteries

    NASA Astrophysics Data System (ADS)

    Chen, Hongning; Zou, Qingli; Liang, Zhuojian; Liu, Hao; Li, Quan; Lu, Yi-Chun

    2015-01-01

    Redox flow batteries are promising technologies for large-scale electricity storage, but have been suffering from low energy density and low volumetric capacity. Here we report a flow cathode that exploits highly concentrated sulphur-impregnated carbon composite, to achieve a catholyte volumetric capacity 294?Ah?l?1 with long cycle life (>100 cycles), high columbic efficiency (>90%, 100 cycles) and high energy efficiency (>80%, 100 cycles). The demonstrated catholyte volumetric capacity is five times higher than the all-vanadium flow batteries (60?Ah?l?1) and 3–6 times higher than the demonstrated lithium-polysulphide approaches (50–117?Ah?l?1). Pseudo-in situ impedance and microscopy characterizations reveal superior electrochemical and morphological reversibility of the sulphur redox reactions. Our approach of exploiting sulphur-impregnated carbon composite in the flow cathode creates effective interfaces between the insulating sulphur and conductive carbon-percolating network and offers a promising direction to develop high-energy-density flow batteries.

  8. Quantitative Assessment of Mycoplasma Hemadsorption Activity by Flow Cytometry

    PubMed Central

    García-Morales, Luis; González-González, Luis; Costa, Manuela; Querol, Enrique; Piñol, Jaume

    2014-01-01

    A number of adherent mycoplasmas have developed highly complex polar structures that are involved in diverse aspects of the biology of these microorganisms and play a key role as virulence factors by promoting adhesion to host cells in the first stages of infection. Attachment activity of mycoplasma cells has been traditionally investigated by determining their hemadsorption ability to red blood cells and it is a distinctive trait widely examined when characterizing the different mycoplasma species. Despite the fact that protocols to qualitatively determine the hemadsorption or hemagglutination of mycoplasmas are straightforward, current methods when investigating hemadsorption at the quantitative level are expensive and poorly reproducible. By using flow cytometry, we have developed a procedure to quantify rapidly and accurately the hemadsorption activity of mycoplasmas in the presence of SYBR Green I, a vital fluorochrome that stains nucleic acids, allowing to resolve erythrocyte and mycoplasma cells by their different size and fluorescence. This method is very reproducible and permits the kinetic analysis of the obtained data and a precise hemadsorption quantification based on standard binding parameters such as the dissociation constant Kd. The procedure we developed could be easily implemented in a standardized assay to test the hemadsorption activity of the growing number of clinical isolates and mutant strains of different mycoplasma species, providing valuable data about the virulence of these microorganisms. PMID:24498118

  9. Two-phase flow in a chemically active porous medium.

    PubMed

    Darmon, Alexandre; Benzaquen, Michael; Salez, Thomas; Dauchot, Olivier

    2014-12-28

    We study the problem of the transformation of a given reactant species into an immiscible product species, as they flow through a chemically active porous medium. We derive the equation governing the evolution of the volume fraction of the species, in a one-dimensional macroscopic description, identify the relevant dimensionless numbers, and provide simple models for capillary pressure and relative permeabilities, which are quantities of crucial importance when tackling multiphase flows in porous media. We set the domain of validity of our models and discuss the importance of viscous coupling terms in the extended Darcy's law. We investigate numerically the steady regime and demonstrate that the spatial transformation rate of the species along the reactor is non-monotonous, as testified by the existence of an inflection point in the volume fraction profiles. We obtain the scaling of the location of this inflection point with the dimensionless lengths of the problem. Eventually, we provide key elements for optimization of the reactor. PMID:25554172

  10. A Stable Vanadium Redox-Flow Battery with High Energy Density for Large-scale Energy Storage

    SciTech Connect

    Li, Liyu; Kim, Soowhan; Wang, Wei; Vijayakumar, M.; Nie, Zimin; Chen, Baowei; Zhang, Jianlu; Xia, Guanguang; Hu, Jian Z.; Graff, Gordon L.; Liu, Jun; Yang, Zhenguo

    2011-05-01

    Low cost, high performance redox flow batteries are highly demanded for up to multi-megawatt levels of renewable and grid energy storage. Here, we report a new vanadium redox flow battery with a significant improvement over the current technologies. This new battery utilizes a sulfate-chloride mixed solution, which is capable of dissolving more than 2.5 M vanadium or about a 70% increase in the energy storage capacity over the current vanadium sulfate system. More importantly, the new electrolyte remains stable over a wide temperature range of -5 to 60oC, potentially eliminating the need of active heat management. Its high energy density, broad operational temperature window, and excellent electrochemical performance would lead to a significant reduction in the cost of energy storage, thus accelerating its market penetration.

  11. U.S. energy flow - 1993

    SciTech Connect

    Borg, I.Y.; Briggs, C.K.

    1994-10-01

    With continued improvement in the economic health of the nation, energy consumption in 1993 increased by almost 2.5%. Use of energy in all major end-use sectors increased, with the largest gains registered in the residential/commercial sector. In this sector, substantial increase in the use of natural gas reflected a harsh 1993-1994 winter as well as broader availability of the fuel for space heating. Crude oil imports rose 8% but stood below the all-time high set in 1977. About half of the increase reflected declining domestic oil production. Imports of natural gas, principally from Canada, increased as they have every year since 1986. They comprise 11% of supply and supplement domestic production, which has similarly risen over the same time span. Increased demand for natural gas is evident in most sectors but especially in the industrial sector, where a growing number of cogenerators of electricity burn natural gas. Although coal consumption in the United States rose 3% in 1993, domestic coal production declined by a greater margin due to a coal strike. Because of increased international competition, exports fell 27%. Electricity transmitted by the utilities again increased, following a decade-long trend interrupted only in 1992 by the national economic recession. The provisions of the Energy Policy Act of 1992 dealing with transport of nonutility-generated electricity by the public utilities began to be implemented in 1993. The provisions of the Energy Policy Act as well as those of the Public Utility Regulatory Policies Act of 1978 are setting the stage for increased competition for customers and for what promises to be a restructuring of the historically monopolistic industry. Nuclear power from the United States`s 109 operable reactors constituted 21% of utility-generated electricity. With the continued retirement of outmoded and flawed reactors, nuclear capacity factors attained 71 in 1993, up from 56% a decade earlier.

  12. Analysis of energy flow during playground surface impacts.

    PubMed

    Davidson, Peter L; Wilson, Suzanne J; Chalmers, David J; Wilson, Barry D; Eager, David; McIntosh, Andrew S

    2013-10-01

    The amount of energy dissipated away from or returned to a child falling onto a surface will influence fracture risk but is not considered in current standards for playground impact-attenuating surfaces. A two-mass rheological computer simulation was used to model energy flow within the wrist and surface during hand impact with playground surfaces, and the potential of this approach to provide insights into such impacts and predict injury risk examined. Acceleration data collected on-site from typical playground surfaces and previously obtained data from children performing an exercise involving freefalling with a fully extended arm provided input. The model identified differences in energy flow properties between playground surfaces and two potentially harmful surface characteristics: more energy was absorbed by (work done on) the wrist during both impact and rebound on rubber surfaces than on bark, and rubber surfaces started to rebound (return energy to the wrist) while the upper limb was still moving downward. Energy flow analysis thus provides information on playground surface characteristics and the impact process, and has the potential to identify fracture risks, inform the development of safer impact-attenuating surfaces, and contribute to development of new energy-based arm fracture injury criteria and tests for use in conjunction with current methods. PMID:23182916

  13. Autonomous Motility of Active Filaments due to Spontaneous Flow-Symmetry Breaking

    E-print Network

    Gayathri Jayaraman; Sanoop Ramachandran; Somdeb Ghose; Abhrajit Laskar; M. Saad Bhamla; P. B. Sunil Kumar; R. Adhikari

    2012-10-10

    We simulate the nonlocal Stokesian hydrodynamics of an elastic filament which is active due a permanent distribution of stresslets along its contour. A bending instability of an initially straight filament spontaneously breaks flow symmetry and leads to autonomous filament motion which, depending on conformational symmetry, can be translational or rotational. At high ratios of activity to elasticity, the linear instability develops into nonlinear fluctuating states with large amplitude deformations. The dynamics of these states can be qualitatively understood as a superposition of translational and rotational motion associated with filament conformational modes of opposite symmetry. Our results can be tested in molecular-motor filament mixtures, synthetic chains of autocatalytic particles, or other linearly connected systems where chemical energy is converted to mechanical energy in a fluid environment.

  14. An experiment with reactive data-flow tasking in active robot vision

    E-print Network

    Paris-Sud XI, Université de

    An experiment with reactive data-flow tasking in active robot vision Eric Rutten, Eric Marchand: formal specification methods, reactive systems, data flow, task preemption, robotics, active vision. 1 in robot vision: active visual recon- struction. This application consists of the specification of a system

  15. Energy flow in an arctic aquatic ecosystem

    SciTech Connect

    Schell, D.M.

    1983-01-01

    This component of the terrestrial-aquatic interaction group seeks to use the natural stable carbon isotope ratios and radiocarbon abundances to trace the movement of photosynthate from the terrestrial environment to the stream system at MS-117. In addition to estimating the total flux, we will also attempt to describe the relative fractions derived from modern primary production and that derived from delayed inputs of eroded peat. We will also seek to determine the coupling efficiency of these energy sources to the invertebrate faunal populations in the tundra soils and streams.

  16. Energy flow in an arctic aquatic ecosystem

    SciTech Connect

    Schell, D.M.

    1983-12-31

    This component of the terrestrial-aquatic interaction group seeks to use the natural stable carbon isotope ratios and radiocarbon abundances to trace the movement of photosynthate from the terrestrial environment to the stream system at MS-117. In addition to estimating the total flux, we will also attempt to describe the relative fractions derived from modern primary production and that derived from delayed inputs of eroded peat. We will also seek to determine the coupling efficiency of these energy sources to the invertebrate faunal populations in the tundra soils and streams.

  17. Study of energy flows in Pantanal - Brazil

    NASA Astrophysics Data System (ADS)

    Santanna, F. B.; Arruda, P. H. Z. D.; Pinto-Jr, O. B.

    2014-12-01

    The main goal of this work was to estimate fluxes using the eddy covariance method in a wetland area, basically with herb-shrub physiognomy, sparse woody vegetation and approximately 4m height. The geographical position of the Pantanal, altitude, latitude, longitude, climate and weather conditions are determined by the dynamics of the atmosphere that affects the whole South America and consequently influence the ecological framework of ecosystems. The results shown by the components considered in the energy balance were more significant during the day, which the atmospheric boundary layer extends from the ground to about 50 or 100 meters height, showing greater instability and turbulence (u* > 0.2 m / s), and this turbulence is what justifies the use of the eddy covariance method to estimate the sensible and latent heat flux. The Pantanal presents seasonal difference between the densities estimates of sensible (H) and latent (LE) heat flux. During the rainy season the sensible heat flux (H) was 30% and the latent heat flux (LE) 58%. During the dry season the sensible heat flux (H) was 46% and the latent heat flux (LE) 40% of the energy budget.

  18. Fully localised nonlinear energy growth optimals in pipe flow

    NASA Astrophysics Data System (ADS)

    Pringle, Chris C. T.; Willis, Ashley P.; Kerswell, Rich R.

    2015-06-01

    A new, fully localised, energy growth optimal is found over large times and in long pipe domains at a given mass flow rate. This optimal emerges at a threshold disturbance energy below which a nonlinear version of the known (streamwise-independent) linear optimal [P. J. Schmid and D. S. Henningson, "Optimal energy density growth in Hagen-Poiseuille flow," J. Fluid Mech. 277, 192-225 (1994)] is selected and appears to remain the optimal up until the critical energy at which transition is triggered. The form of this optimal is similar to that found in short pipes [Pringle et al., "Minimal seeds for shear flow turbulence: Using nonlinear transient growth to touch the edge of chaos," J. Fluid Mech. 702, 415-443 (2012)], but now with full localisation in the streamwise direction. This fully localised optimal perturbation represents the best approximation yet of the minimal seed (the smallest perturbation which is arbitrarily close to states capable of triggering a turbulent episode) for "real" (laboratory) pipe flows. Dependence of the optimal with respect to several parameters has been computed and establishes that the structure is robust.

  19. Energy Flow: A Multimodal `Ready' Indication For Electric Vehicles

    E-print Network

    Energy Flow: A Multimodal `Ready' Indication For Electric Vehicles Abstract The lack of sound and vibration while starting the drive system of an electric vehicle (EV) is one of the major differences; Electric Vehicle; User Experience Introduction The slow but consistently increasing distribution

  20. Energy flow along the medium-induced parton cascade

    E-print Network

    Jean-Paul Blaizot; Yacine Mehtar-Tani

    2015-01-14

    We discuss the dynamics of parton cascades that develop in dense QCD matter, and contrast their properties with those of similar cascades of gluon radiation in vacuum. We argue that such cascades belong to two distinct classes that are characterized respectively by an increasing or a constant (or decreasing) branching rate along the cascade. In the former class, of which the BDMPS, medium-induced, cascade constitutes a typical example, it takes a finite time to transport a finite amount of energy to very soft quanta, while this time is essentially infinite in the latter case, to which the DGLAP cascade belongs. The medium induced cascade is accompanied by a constant flow of energy towards arbitrary soft modes, leading eventually to the accumulation of the initial energy of the leading particle at zero energy. It also exhibits scaling properties akin to wave turbulence. These properties do not show up in the cascade that develops in vacuum. There, the energy accumulates in the spectrum at smaller and smaller energy as the cascade develops, but the energy never flows all the way down to zero energy. Our analysis suggests that the way the energy is shared among the offsprings of a splitting gluon has little impact on the qualitative properties of the cascades, provided the kernel that governs the splittings is not too singular.

  1. Waste to Energy Time Activities

    E-print Network

    :40-10:10 Presentation of Dr. Kalogirou, "Waste to Energy: An Integral Part of Worldwide Sustainable Waste Management" 10 recovery from solid wastes, potable water resources, ozone sterilization technologies. He has a PhD and Post-Doctorate in waste management. She is the founder and chief Scientist of ALKEMY, a US - company

  2. Irreducible Representations of Oscillatory and Swirling Flows in Active Soft Matter

    NASA Astrophysics Data System (ADS)

    Ghose, Somdeb; Adhikari, R.

    2014-03-01

    Recent experiments imaging fluid flow around swimming microorganisms have revealed complex time-dependent velocity fields that differ qualitatively from the stresslet flow commonly employed in theoretical descriptions of active matter. Here we obtain the most general flow around a finite sized active particle by expanding the surface stress in irreducible Cartesian tensors. This expansion, whose first term is the stresslet, must include, respectively, third-rank polar and axial tensors to minimally capture crucial features of the active oscillatory flow around translating Chlamydomonas and the active swirling flow around rotating Volvox. The representation provides explicit expressions for the irreducible symmetric, antisymmetric, and isotropic parts of the continuum active stress. Antisymmetric active stresses do not conserve orbital angular momentum and our work thus shows that spin angular momentum is necessary to restore angular momentum conservation in continuum hydrodynamic descriptions of active soft matter.

  3. Irreducible representations of oscillatory and swirling flows in active soft matter.

    PubMed

    Ghose, Somdeb; Adhikari, R

    2014-03-21

    Recent experiments imaging fluid flow around swimming microorganisms have revealed complex time-dependent velocity fields that differ qualitatively from the stresslet flow commonly employed in theoretical descriptions of active matter. Here we obtain the most general flow around a finite sized active particle by expanding the surface stress in irreducible Cartesian tensors. This expansion, whose first term is the stresslet, must include, respectively, third-rank polar and axial tensors to minimally capture crucial features of the active oscillatory flow around translating Chlamydomonas and the active swirling flow around rotating Volvox. The representation provides explicit expressions for the irreducible symmetric, antisymmetric, and isotropic parts of the continuum active stress. Antisymmetric active stresses do not conserve orbital angular momentum and our work thus shows that spin angular momentum is necessary to restore angular momentum conservation in continuum hydrodynamic descriptions of active soft matter. PMID:24702422

  4. Active control of tip clearance flow in axial compressors

    E-print Network

    Bae, Jinwoo W

    2001-01-01

    Control of compressor tip clearance flows is explored in a linear cascade using three types of fluidic actuators; Normal Synthetic Jet (NSJ; unsteady jet normal to the mean flow with zero net mass flux), Directed Synthetic ...

  5. Active flow separation control using synthetic jet actuators 

    E-print Network

    Rao, Preetham P

    2000-01-01

    The use of synthetic jet actuators for controlling the boundary layer flow and flow separation over a wing is investigated. A theory for the optimum design of actuators using motors is developed. A motor driven synthetic jet actuator is built...

  6. Active flow separation control using synthetic jet actuators

    E-print Network

    Rao, Preetham P

    2000-01-01

    The use of synthetic jet actuators for controlling the boundary layer flow and flow separation over a wing is investigated. A theory for the optimum design of actuators using motors is developed. A motor driven synthetic jet actuator is built...

  7. An overview of active flow control actuators and applications (presentation video)

    NASA Astrophysics Data System (ADS)

    Brzozowski, Daniel; Whalen, Edward A.

    2014-04-01

    Active Flow Control (AFC) is an emerging technology which promises performance enhancements to both military and civilian aircraft. A technique which uses energy input at discrete locations to manipulate the flow over an aerodynamic surface, AFC may be used to reduce drag, prevent flow separation, and enable otherwise-infeasible aerodynamic designs. Additional applications include shear layer and turbulence control for aero-optics applications and mixing enhancement for thermal applications. Many AFC applications call for a high frequency fluidic perturbation provided by an electrically-powered actuator. In these instances, piezoelectric (PZT) materials have served as the workhorse for flow control actuators, such as the widely-studied synthetic jet. Because the PZT materials form the critical component of the actuator, the maximum performance of the synthetic jet (velocity and momentum output) is limited by the physical limitations of the PZT material. The purpose of this presentation is to provide a high level overview of AFC actuators and applications in an attempt to engage the smart materials community and encourage advanced material development in support of these crucial applications.

  8. Nematomorph parasites drive energy flow through a riparian ecosystem

    USGS Publications Warehouse

    Sato, Takuya; Wtanabe, Katsutoshi; Kanaiwa, Minoru; Niizuma, Yasuaki; Harada, Yasushi; Lafferty, Kevin D.

    2011-01-01

    Parasites are ubiquitous in natural systems and ecosystem-level effects should be proportional to the amount of biomass or energy flow altered by the parasites. Here we quantified the extent to which a manipulative parasite altered the flow of energy through a forest-stream ecosystem. In a Japanese headwater stream, camel crickets and grasshoppers (Orthoptera) were 20 times more likely to enter a stream if infected by a nematomorph parasite (Gordionus spp.), corroborating evidence that nematomorphs manipulate their hosts to seek water where the parasites emerge as free-living adults. Endangered Japanese trout (Salvelinus leucomaenis japonicus) readily ate these infected orthopterans, which due to their abundance, accounted for 60% of the annual energy intake of the trout population. Trout grew fastest in the fall, when nematomorphs were driving energy-rich orthopterans into the stream. When infected orthopterans were available, trout did not eat benthic invertebrates in proportion to their abundance, leading to the potential for cascading, indirect effects through the forest-stream ecosystem. These results provide the first quantitative evidence that a manipulative parasite can dramatically alter the flow of energy through and across ecosystems.

  9. Energy harvesting efficiency of piezoelectric flags in axial flows

    E-print Network

    Michelin, Sebastien

    2012-01-01

    Self-sustained oscillations resulting from fluid-solid instabilities, such as the flutter of a flexible flag in axial flow, can be used to harvest energy if one is able to convert the solid energy into electricity. Here, this is achieved using piezoelectric patches attached to the surface of the flag that convert the solid deformation into an electric current powering purely resistive output circuits. Nonlinear numerical simulations in the slender-body limit, based on an explicit description of the coupling between the fluid-solid and electric systems, are used to determine the harvesting efficiency of the system, namely the fraction of the flow kinetic energy flux effectively used to power the output circuit, and its evolution with the system's parameters. The role of the tuning between the characteristic frequencies of the fluid-solid and electric systems is emphasized, as well as the critical impact of the piezoelectric coupling intensity. High fluid loading, classically associated with destabilization by ...

  10. Dimensions of Flow in Academic and Social Activities among Summer Music Camp participants

    ERIC Educational Resources Information Center

    Diaz, Frank M.; Silveira, Jason M.

    2013-01-01

    The purpose of this study was to investigate the occurrence of flow experiences among high school music students attending a two-week summer instrumental music camp. Specifically, the study sought to determine if: (1) students do indeed experience flow in summer camp settings; (2) what activities are conducive to flow; (3) what is the relationship…

  11. Horizontal Flows in the Photosphere and Subphotosphere of Two Active Regions

    NASA Technical Reports Server (NTRS)

    Liu, Yang; Zhao, Junwei; Schuck, P. W.

    2012-01-01

    We compare horizontal flow fields in the photosphere and in the subphotosphere (a layer 0.5 megameters below the photosphere) in two solar active regions: AR11084 and AR11158. AR11084 is a mature, simple active region without significant flaring activity, and AR11158 is a multipolar, complex active region with magnetic flux emerging during the period studied. Flows in the photosphere are derived by applying the Differential Affine Velocity Estimator for Vector Magnetograms (DAVE4VM) on HMI-observed vector magnetic fields, and the subphotospheric flows are inferred by time-distance helioseismology using HMI-observed Dopplergrams. Similar flow patterns are found for both layers for AR11084: inward flows in the sunspot umbra and outward flows surrounding the sunspot. The boundary between the inward and outward flows, which is slightly different in the photosphere and the subphotosphere, is within the sunspot penumbra. The area having inward flows in the subphotosphere is larger than that in the photosphere. For AR11158, flows in these two layers show great similarities in some areas and significant differences in other areas. Both layers exhibit consistent outward flows in the areas surrounding sunspots. On the other hand, most well-documented flux-emergence-related flow features seen in the photosphere do not have counterparts in the subphotosphere. This implies that the horizontal flows caused by flux emergence do not extend deeply into the subsurface.

  12. Water flow based geometric active deformable model for road network

    NASA Astrophysics Data System (ADS)

    Leninisha, Shanmugam; Vani, Kaliaperumal

    2015-04-01

    A width and color based geometric active deformable model is proposed for road network extraction from remote sensing images with minimal human interception. Orientation and width of road are computed from a single manual seed point, from which the propagation starts both right and left hand directions of the starting point, which extracts the interconnected road network from the aerial or high spatial resolution satellite image automatically. Here the propagation (like water flow in canal with defined boundary) is restricted with color and width of the road. Road extraction is done for linear, curvilinear (U shape and S shape) roads first, irrespective of width and color. Then, this algorithm is improved to extract road with junctions in a shape of L, T and X along with center line. Roads with small break or disconnected roads are also extracts by a modified version of this same algorithm. This methodology is tested and evaluated with various remote sensing images. The experimental results show that the proposed method is efficient and extracting roads accurately with less computation time. However, in complex urban areas, the identification accuracy declines due to the various sizes of obstacles, over bridges, multilane etc.

  13. Harvesting energy via fluttering piezoelectric beams in viscous flow

    NASA Astrophysics Data System (ADS)

    Akcabay, Deniz; Young, Yin

    2011-11-01

    This work explores the idea of harvesting energy from ambient flows using flexible piezoelectric beams. Beams lose their stability and flutter above a critical length or flow speed or below a critical stiffness. During flutter, beams oscillate in increasing amplitude until they enter a self-sustained limit cycle oscillation, which could be exploited to harvest energy. The objectives of this study are to: (i) identify the flutter boundary of a flexible beam in viscous flow; (ii) explore the energy harvesting potential; and (iii) identify critical non-dimensional parameters and parametric relations that govern the response and stability of thin composite beams vibrating in a viscous fluid. Two-dimensional Navier-Stokes equations are solved with a nonlinear beam model coupled with a linear piezoelectric material constitutive model. The harvested energy potential for various solid/fluid combinations is investigated by varying the critical non-dimensional parameters, which are defined in terms of beam length, density, thickness, and stiffness; fluid speed and density; and piezoelectric material properties.

  14. Observations of shear flows in high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Harding, Eric C.

    The research discussed in this thesis represents work toward the demonstration of experimental designs for creating a Kelvin-Helmholtz (KH) unstable shear layer in a high-energy-density (HED) plasma. Such plasmas are formed by irradiating materials with several kilo-Joules of laser light over a few nanoseconds, and are defined as having an internal pressure greater than one-million atmospheres. Similar plasmas exist in laboratory fusion experiments and in the astrophysical environment. The KH instability is a fundamental fluid instability that arises when strong velocity gradients exist at the interface between two fluids. The KH instability is important because it drives the mixing of fluids and initiates the transition to turbulence in the flow. Until now, the evolution of the KH instability has remained relatively unexplored in the HED regime This thesis presents the observations and analysis of two novel experiments carried out using two separate laser facilities. The first experiment used 1.4 kJ from the Nike laser to generate a supersonic flow of Al plasma over a low-density, rippled foam surface. The Al flow interacted with the foam and created distinct features that resulted from compressible effects. In this experiment there is little evidence of the KH instability. Nevertheless, this experimental design has perhaps pioneered a new method for generating a supersonic shear flow that has the potential to produce the KH instability if more laser energy is applied. The second experiment was performed on the Omega laser. In this case 4.3 kJ of laser energy drove a blast wave along a rippled foam/plastic interface. In response to the vorticity deposited and the shear flow established by the blast wave, the interface rolls up into large vorticies characteristic of the KH instability. The Omega experiment was the first HED experiment to capture the evolution of the KH instability.

  15. Relative Activity of Brook Trout and Walleyes in Response to Flow in a Regulated River

    Microsoft Academic Search

    Karen J. Murchie; Karen E. Smokorowski

    2004-01-01

    Coded electromyogram telemetry transmitters were used to examine the effects of varying flows on the relative activity of brook trout Salvelinus fontinalis and walleye Sander vitreus in a regulated river. The relative activity levels of two brook trout and two walleyes were continuously monitored for a minimum of 24 h, and measurements were compared with river flow values logged at

  16. The propagation of kinetic energy across scales in turbulent flows

    E-print Network

    Cardesa, José I; Dong, Siwei; Jiménez, Javier

    2015-01-01

    A temporal study of energy transfer across length scales is performed in 3D numerical simulations of homogeneous shear flow and isotropic turbulence, at Reynolds numbers in the range $Re_{\\lambda}=107-384$. The average time taken by perturbations in the energy flux to travel between scales is measured and shown to be additive, as inferred from the agreement between the total travel time from a given scale to the smallest dissipative motions, and the time estimated from successive jumps through intermediate scales. Our data suggests that the propagation of disturbances in the energy flux is independent of the forcing and that it defines a `velocity' that determines the energy flux itself. These results support that the cascade is, on average, a scale-local process where energy is continuously transmitted from one scale to the next in order of decreasing size.

  17. Magnetic Energy Storage in Coronal Active Regions

    NASA Astrophysics Data System (ADS)

    Wolfson, Richard; Drake, C.; Kennedy, M.

    2011-05-01

    We consider magnetic energy storage in a force-free coronal model that simulates an active region by superposing a strong, localized magnetic bipole on a global background dipole. As we found earlier for dipolar and quadrupolar boundary conditions, our solutions develop detached flux ropes, whose energy can exceed that of the corresponding open field; this excess energy is available to power eruptive events such as coronal mass ejections. Our earlier work, and that of others on related magnetic configurations, has generally yielded excess energies of at most approximately 25 percent of the corresponding potential-field energy. Our new active-region models greatly exceed that value, with stressed force-free fields whose energy excess above the open-field state can be well over 100 percent of the energy stored in the associated potential field. Moving the model active region poleward increases the maximum value of this excess stored energy. This work is funded by NSF grant AGS0940503 to Middlebury College.

  18. The evolution of an active silicic lava flow field: an ETM+ perspective

    Microsoft Academic Search

    Andrew J. L Harris; Luke P Flynn; Otoniel Matias; William I Rose; Julio Cornejo

    2004-01-01

    An active dacitic lava flow began advancing down the south flank of the Caliente dome unit (Santiaguito Volcano, Guatemala) during July 1999. By January 2002 continued activity had built a ?1-km2, 66×106 m3 flow field. Using a time series of Landsat 7 ETM+ images and field observations the evolution and characteristics of this flow field are described. Throughout the period

  19. Flow Structures and Energy Capture from an Oscillating Hydrofoil

    NASA Astrophysics Data System (ADS)

    Franck, Jennifer; Frank, Sarah; Mandre, Shreyas

    2013-11-01

    The flow surrounding an oscillating hydrofoil in a uniform freestream is computationally investigated for hydrokinetic energy capture. Simulations are performed on an elliptical hydrofoil using 2D Direct Numerical Simulation (DNS) for low Reynolds number and 3D Large-Eddy Simulations (LES) for high Reynolds number simulations at 80,000. A non-inertial reference frame is utilized for rigid-body motion of the hydrofoil, which is prescribed a sinusoidal motion in pitch and heave. The kinematic parameters are varied and the resulting flow features are correlated with positive or negative energy capture. In an effort to optimize the stroke, variations in the sinusoidal heave and pitch signals are systematically explored and analyzed for future closed-loop control.

  20. Energy function for an interline power-flow controller

    Microsoft Academic Search

    V. Azbe; R. Mihalic

    2009-01-01

    An IPFC may be applied for steady-state power-flow and voltage control as well as for mastering dynamic phenomena like transient-stability margin enhancement, oscillation damping, etc. For these tasks the Lyapunov energy-function approach is frequently used as a convenient way to control or analyze the electric-power system (EPS). The basis for the implementation of such an approach is to know the

  1. OWC wave energy devices with air flow control

    Microsoft Academic Search

    A. F. de O. Falcão; P. A. P. Justino

    1999-01-01

    A theoretical model is developed to simulate the energy conversion, from wave to turbine shaft, of an oscillating-water-column (OWC) plant equipped with a Wells air-turbine and with a valve (in series or in parallel with the turbine) for air-flow control. Numerical simulations show that the use of a control valve, by preventing or reducing the aerodynamic stall losses at the

  2. Advanced Redox Flow Batteries for Stationary Electrical Energy Storage

    SciTech Connect

    Li, Liyu; Kim, Soowhan; Xia, Guanguang; Wang, Wei; Yang, Zhenguo

    2012-03-19

    This report describes the status of the advanced redox flow battery research being performed at Pacific Northwest National Laboratories for the U.S. Department of Energy’s Energy Storage Systems Program. The Quarter 1 of FY2012 Milestone was completed on time. The milestone entails completion of evaluation and optimization of single cell components for the two advanced redox flow battery electrolyte chemistries recently developed at the lab, the all vanadium (V) mixed acid and V-Fe mixed acid solutions. All the single cell components to be used in future kW-scale stacks have been identified and optimized in this quarter, which include solution electrolyte, membrane or separator; carbon felt electrode and bi-polar plate. Varied electrochemical, chemical and physical evaluations were carried out to assist the component screening and optimization. The mechanisms of the battery capacity fading behavior for the all vanadium redox flow and the Fe/V battery were discovered, which allowed us to optimize the related cell operation parameters and continuously operate the system for more than three months without any capacity decay.

  3. Bidirectional control system for energy flow in solar powered flywheel

    SciTech Connect

    Nola, F.J.

    1987-03-10

    An energy supply system is described for a spacecraft for supplying energy to at least one spacecraft load, the system comprising: a flywheel; an electric motor connected to the flywheel for selectively supplying electrical power to the spacecraft load; solar energy conversion means for receiving solar energy and for converting the received solar energy into an output voltage for supply to the spacecraft load; and electrical control means for (1) sensing the spacecraft load voltage, and feeding back the sensed voltage to regulate the voltage supplied to the spacecraft load when the spacecraft load voltage changes, and for (2) comparing the output voltage from the solar energy conversion means with a threshold voltage and, when the threshold voltage is exceeded, activating a speed control loop including the motor so as to accelerate the flywheel to a constant speed to thereby convert the electrical energy supplied from the solar energy conversion means into mechanical energy. When the threshold voltage is not exceeded, the speed control loop is deactivated and a voltage control loop is activated for controlling the amount of mechanical energy from the flywheel which is converted into an electrical energy output from the motor for supply to the spacecraft load in according with the sensed load voltage.

  4. Flow-induced nonequilibrium self-assembly in suspensions of stiff, apolar, active filaments

    E-print Network

    Pandey, Ankita; Adhikari, R

    2014-01-01

    Active bodies in viscous fluids interact hydrodynamically through self-generated flows. Here we study spontaneous aggregation induced by hydrodynamic flow in a suspension of stiff, apolar, active filaments. Lateral hydrodynamic attractions in extensile filaments lead, independent of volume fraction, to anisotropic aggregates which translate and rotate ballistically. Lateral hydrodynamic repulsion in contractile filaments lead, with increasing volume fractions, to microstructured states of asters, clusters, and incipient gels where, in each case, filament motion is diffusive. Our results demonstrate that the interplay of active hydrodynamic flows and anisotropic excluded volume interactions provides a generic nonequilibrium mechanism for hierarchical self-assembly of active soft matter.

  5. Flow-induced nonequilibrium self-assembly in suspensions of stiff, apolar, active filaments

    E-print Network

    Ankita Pandey; P. B. Sunil Kumar; R. Adhikari

    2014-08-02

    Active bodies in viscous fluids interact hydrodynamically through self-generated flows. Here we study spontaneous aggregation induced by hydrodynamic flow in a suspension of stiff, apolar, active filaments. Lateral hydrodynamic attractions in extensile filaments lead, independent of volume fraction, to anisotropic aggregates which translate and rotate ballistically. Lateral hydrodynamic repulsion in contractile filaments lead, with increasing volume fractions, to microstructured states of asters, clusters, and incipient gels where, in each case, filament motion is diffusive. Our results demonstrate that the interplay of active hydrodynamic flows and anisotropic excluded volume interactions provides a generic nonequilibrium mechanism for hierarchical self-assembly of active soft matter.

  6. Low angular momentum flow model of Sgr A* activity

    E-print Network

    B. Czerny; M. Moscibrodzka

    2008-08-21

    Sgr A* is the closest massive black hole and can be observed with the highest angular resolution. Nevertheless, our current understanding of the accretion process in this source is very poor. The inflow is almost certainly of low radiative efficiency and it is accompanied by a strong outflow and the flow is strongly variable but the details of the dynamics are unknown. Even the amount of angular momentum in the flow is an open question. Here we argue that low angular momentum scenario is better suited to explain the flow variability. We present a new hybrid model which describes such a flow and consists of an outer spherically symmetric Bondi flow and an inner axially symmetric flow described through MHD simulations. The assumed angular momentum of the matter is low, i.e. the corresponding circularization radius in the equatorial plane of the flow is just above the innermost stable circular orbit in pseudo-Newtonian potential. We compare the radiation spectrum from such a flow to the broad band observational data for Sgr A*.

  7. Chemical activation through super energy transfer collisions.

    PubMed

    Smith, Jonathan M; Nikow, Matthew; Ma, Jianqiang; Wilhelm, Michael J; Han, Yong-Chang; Sharma, Amit R; Bowman, Joel M; Dai, Hai-Lung

    2014-02-01

    Can a molecule be efficiently activated with a large amount of energy in a single collision with a fast atom? If so, this type of collision will greatly affect molecular reactivity and equilibrium in systems where abundant hot atoms exist. Conventional expectation of molecular energy transfer (ET) is that the probability decreases exponentially with the amount of energy transferred, hence the probability of what we label "super energy transfer" is negligible. We show, however, that in collisions between an atom and a molecule for which chemical reactions may occur, such as those between a translationally hot H atom and an ambient acetylene (HCCH) or sulfur dioxide, ET of chemically significant amounts of energy commences with surprisingly high efficiency through chemical complex formation. Time-resolved infrared emission observations are supported by quasi-classical trajectory calculations on a global ab initio potential energy surface. Results show that ?10% of collisions between H atoms moving with ?60 kcal/mol energy and HCCH result in transfer of up to 70% of this energy to activate internal degrees of freedom. PMID:24428264

  8. Velocity fluctuations and energy amplification in laminar fluid flows

    NASA Astrophysics Data System (ADS)

    Ortiz de Zarate, Jose M.; Sengers, Jan V.

    2008-11-01

    We present a systematic procedure for evaluating the intrinsic velocity fluctuations and the resulting intrinsic energy amplification that are always present in laminar fluid flows. For this purpose we formulate a stochastic Orr-Sommerfeld equation and a stochastic Squire equation by applying a fluctuation-dissipation theorem for the random part of the dissipative stresses. From the solution of the stochastic Orr- Sommerfeld and Squire equations the intrinsic energy amplification can be deduced. As an illustration of the procedure we present an explicit solution for the case of planar Couette flow. We first solve the fluctuating hydrodynamics equations in the bulk, obtaining an exact representation of the spatial spectrum of the velocity fluctuations valid for large wave numbers. The resulting energy amplification is proportional to Re^3/2. Next, we show how to a good approximation confinement can be incorporated by a simple Galerkin projection technique. The effect of the boundary conditions is to reduce the energy amplification to a logarithmic dependence on Re. We shall also indicate how an exact solution for the case of confined geometries can be obtained by an expansion into a set of hydrodynamic modes, conveniently expressed in terms of Airy functions.

  9. Energy Activities for Junior High Social Studies.

    ERIC Educational Resources Information Center

    Minnesota State Energy Agency, St. Paul.

    The document contains seven learning activities for junior high students on the energy situation. Objectives are to help students gain understanding and knowledge about the relationships between humans and their social and physical environments; solve problems and clarify issues; examine personal beliefs and values; and recognize the relationships…

  10. Solar Energy Project, Activities: Chemistry & Physics.

    ERIC Educational Resources Information Center

    Tullock, Bruce, Ed.; And Others

    This guide contains lesson plans and outlines of science activities which present concepts of solar energy in the context of chemistry and physics experiments. Each unit presents an introduction to the unit; objectives; required skills and knowledge; materials; method; questions; recommendations for further work; and a teacher information sheet.…

  11. Active separation control of high-Re turbulent separated flow over a wall-mounted hump using RANS, DES, and LES turbulence modeling approaches

    NASA Astrophysics Data System (ADS)

    Gan, Subhadeep

    Most practical flows in engineering applications are turbulent, and exhibit separation which is generally undesirable because of its adverse effects on performance and efficiency. Therefore, control of turbulent separated flows has been a topic of significant interest as it can reduce separation losses. Often, flow control work employs passive techniques to manipulate the flow. Passive-flow control does not require any additional energy source to achieve the control, but is accompanied by additional viscous losses. It is more desirable to employ active techniques as these can be turned on and off, depending on the flow control requirement. The primary goal of the present work is to numerically investigate a high Reynolds number turbulent separated flow. It is Case 3 of the 2004 CFD Validation on Synthetic Jets and Turbulent Separation Control Workshop, http://cfdval2004.larc.nasa.gov/case3.html, conducted by NASA for the flow over a wall-mounted hump. Followed by the baseline flow simulation, i.e., without flow control, active flow control will be investigated using both steady suction jet as well as a "synthetic" jet. Use of synthetic jets has gained popularity in recent times for active flow control because of their ability to transfer linear momentum to the flow system without net-mass injection across the boundary in the vicinity of separation. The present work also implements the use of two jets (steady suction and synthetic jets) as have not been previously implemented for this flow model. For the synthetic-jets case, the work also studies the effect of two jets in opposite phase. The secondary goal of this work is to bring together a variety of turbulence models and simulation approaches for one flow problem. Turbulent Couette flow was used as a model flow problem to validate the flow solver and investigate the performance of different turbulence models and approaches. The flow is simulated using steady and unsteady-state three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations-based turbulence models and three-dimensional time-dependent Detached Eddy Simulation (DES) and Large-Eddy Simulation (LES) methods. Multiple turbulence modeling approaches help to ascertain what models are most appropriate for capturing the physics of this complex separated flow. The various turbulence modeling cases are simulated with the same grid and solution methodology, and the turbulence models' equations are solved with the same numerical method. This ensures that the variances amongst the results obtained with different models are exclusively due to use of the different turbulence models, and indeed enable assessment of the performance of these models with respect to one another. The results will help us better decide what models to choose for flows with adverse pressure gradients, flow separation and control of separated flows. Validation work using Turbulent Couette flow demonstrates that, for LES, a fine enough grid is required throughout the computational domain and not just near the wall, to capture the turbulent flow structures and flow physics. For the flow over the wall-mounted hump, the simulation results agree well with experiment. Significant computational-resources savings was realized by using an analytical exit velocity profile for the active flow control jets, instead of simulating the entire flow-control manifold without sacrificing the quality of the work. Results compared with experimental values were surface pressure coefficient, skin friction coefficient, mean velocity profiles, Reynolds stresses and flow reattachment locations. Simulation results show some degree of variation with experimental results in the separated flow region. The steady-suction active control was able to reduce the reattachment length the most. The region of negative streamwise velocity was the smallest in the active flow control with steady suction. The multiple jets cases, with steady suction and synthetic jets, were able to reduce the length of separation bubble in comparison to the corresponding single jet cases. Th

  12. Mass and Energy Flow Through the Jovian Magnetosphere

    NASA Astrophysics Data System (ADS)

    Bagenal, F.; Delamere, P. A.

    2010-12-01

    We a simple model of the flow of mass and energy through the jovian magnetosphere based on Voyager, Galileo and Cassini data. Combining the observed distribution of mass with conservation of the ~500 kg/s flux of Iogenic material we derive net radial flows that reach the local Alfven speed around 50-60 Rj. Estimates of mass ejected down the magnetotail in plasmoids only add up to a few percent of the source, suggesting most of the material must either be lost as a steady drizzle down the tail or leak out of the magnetopause. Approximately 230 tons of solar wind protons bombard the magnetopause each second. Thus, only a few percent leaking into the magnetosphere would swamp the mass source at Io. The dominance of sulfur and oxygen ions in the inner and middle magnetosphere indicate that little of such a solar wind source penetrates far into the magnetosphere. But mixing of iogenic and solar wind plasma (such as via Kelvin-Helmholtz instabilities) may be prevalent in the outer regions. The flow of energy through the system is not so clear to understand. Models of the physical chemistry of the Io plasma torus are consistent with a substantial source of energy from ion pick-up. But additional energy must also be pumped into the population of hot electrons (perhaps via plasma waves or as a dissipative by-product of fluxtube interchange motions). Most of the power going into the torus is radiated as UV line emission (1.2-2.5 TW) with only a little being carried by the outwardly diffusing plasma. As the plasma expands out into the large volumes of the middle and outer magnetosphere one would expect the plasma to cool. But the plasma temperature is observed to increase with distance and one of the major unresolved mysteries of the magnetosphere is how the plasma is in fact heated as it moves outwards. Approximately 0.6-3 TW of kinetic energy and 2.7-15 TW of thermal energy must be added to the plasma in the plasma disk. The ultimate source of this energy is likely Jupiter's rotation (coupled to the magnetodisk via the magnetic field) but some of the 2 x 10^4 TW of kinetic energy of the solar wind impinging on the magnetotail is likely tapped in the outer magnetosphere.

  13. Energy dissipation in oscillating flow through straight and coiled pipes

    SciTech Connect

    Olson, J.R.; Swift, G.W. [Condensed Matter and Thermal Physics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1996-10-01

    The energy dissipation is reported for oscillating flow in U-shaped pipes with 180{degree}, 540{degree}, and 900{degree} curves at the base of the U. Analysis permits separation of the dissipation in the straight and curved portions of the pipe. Using water, water/glycerine mixtures, liquid nitrogen, and helium gas, the dissipation was measured for fluid flow regimes (Reynolds number, quality factor, and pipe curvature) which have not previously been reported. Measured loss in the straight portion is compared to numerical solutions using a turbulent quasisteady representation of the wall shear stress. Measured loss in the curved portion is compared to simple theory. The results are applicable to thermoacoustic devices. {copyright} {ital 1996 Acoustical Society of America.}

  14. The Magnetic Free Energy in Active Regions

    NASA Technical Reports Server (NTRS)

    Metcalf, Thomas R.; Mickey, Donald L.; LaBonte, Barry J.

    2001-01-01

    The magnetic field permeating the solar atmosphere governs much of the structure, morphology, brightness, and dynamics observed on the Sun. The magnetic field, especially in active regions, is thought to provide the power for energetic events in the solar corona, such as solar flares and Coronal Mass Ejections (CME) and is believed to energize the hot coronal plasma seen in extreme ultraviolet or X-rays. The question remains what specific aspect of the magnetic flux governs the observed variability. To directly understand the role of the magnetic field in energizing the solar corona, it is necessary to measure the free magnetic energy available in active regions. The grant now expiring has demonstrated a new and valuable technique for observing the magnetic free energy in active regions as a function of time.

  15. Numerical studies of the application of active flow control to subsonic and transonic airfoil flows using a synthetic jet actuator

    Microsoft Academic Search

    Jose L. Vadillo

    2005-01-01

    Active control of flow over airfoils is currently an area of heightened interest in the aerospace community because of its potential in reducing drag, eliminating separation at high angles of attack, and modulating the aerodynamic forces and moments. We study these possibilities by performing several numerical simulations. Numerical simulations are performed by employing an Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations solver

  16. Solar Energy Education. Renewable energy activities for earth science

    SciTech Connect

    Not Available

    1980-01-01

    A teaching manual is provided to aid teachers in introducing renewable energy topics to earth science students. The main emphasis is placed on solar energy. Activities for the student include a study of the greenhouse effect, solar gain for home heating, measuring solar radiation, and the construction of a model solar still to obtain fresh water. Instructions for the construction of apparatus to demonstrate a solar still, the greenhouse effect and measurement of the altitude and azimuth of the sun are included. (BCS)

  17. Flow based vs. demand based energy-water modelling

    NASA Astrophysics Data System (ADS)

    Rozos, Evangelos; Nikolopoulos, Dionysis; Efstratiadis, Andreas; Koukouvinos, Antonios; Makropoulos, Christos

    2015-04-01

    The water flow in hydro-power generation systems is often used downstream to cover other type of demands like irrigation and water supply. However, the typical case is that the energy demand (operation of hydro-power plant) and the water demand do not coincide. Furthermore, the water inflow into a reservoir is a stochastic process. Things become more complicated if renewable resources (wind-turbines or photovoltaic panels) are included into the system. For this reason, the assessment and optimization of the operation of hydro-power systems are challenging tasks that require computer modelling. This modelling should not only simulate the water budget of the reservoirs and the energy production/consumption (pumped-storage), but should also take into account the constraints imposed by the natural or artificial water network using a flow routing algorithm. HYDRONOMEAS, for example, uses an elegant mathematical approach (digraph) to calculate the flow in a water network based on: the demands (input timeseries), the water availability (simulated) and the capacity of the transmission components (properties of channels, rivers, pipes, etc.). The input timeseries of demand should be estimated by another model and linked to the corresponding network nodes. A model that could be used to estimate these timeseries is UWOT. UWOT is a bottom up urban water cycle model that simulates the generation, aggregation and routing of water demand signals. In this study, we explore the potentials of UWOT in simulating the operation of complex hydrosystems that include energy generation. The evident advantage of this approach is the use of a single model instead of one for estimation of demands and another for the system simulation. An application of UWOT in a large scale system is attempted in mainland Greece in an area extending over 130×170 km². The challenges, the peculiarities and the advantages of this approach are examined and critically discussed.

  18. Experiments on active control of vibrational power flow using piezoceramic actuators and sensors

    NASA Technical Reports Server (NTRS)

    Gibbs, Gary P.; Fuller, Chris R.

    1990-01-01

    The active control of flexural power flow in both semiinfinite and finite elastic beams is experimentally investigated. The experimental results demonstrate that piezoceramic transducers when used in conjunction with an adaptive least mean squares controller, can effectively control flexural power flow in thin beam systems. The piezoceramic transducers offer distinct size and weight advantages over conventional transducers. The experiments also demonstrate the use of an axial scanning laser vibrometer to determine out of plane velocity and power flow.

  19. UML 2 activity model support for systems engineering functional flow diagrams

    Microsoft Academic Search

    Conrad Bock

    2003-01-01

    This article compares Activity models of the Unified Modeling Language, version 2 (UML 2) (OMG (Object Management Group), UML 2.0 superstructure specification, August 2003, http:\\/\\/www.omg.org\\/cgi-bin\\/doc?ptc\\/03-08-02), to a widely-used systems engineering (SE) flow diagram, the Enhanced Functional Flow Block Diagram (EFFBD) (J. Long, Relationships between common graphical representations in system engineering, ViTech Corporation, 2002), and to the requirements for functional flow

  20. Symmetry energy from elliptic flow in 197Au + 197Au

    E-print Network

    P. Russotto; P. Z. Wu; M. Zoric; M. Chartier; Y. Leifels; R. C. Lemmon; Q. Li; J. Lukasik; A. Pagano; P. Pawlowski; W. Trautmann

    2011-01-12

    The elliptic-flow ratio of neutrons with respect to protons or light complex particles in reactions of neutron-rich systems at relativistic energies is proposed as an observable sensitive to the strength of the symmetry term in the equation of state at supra-normal densities. The results obtained from the existing FOPI/LAND data for 197Au + 197Au collisions at 400 MeV/nucleon in comparison with the UrQMD model favor a moderately soft symmetry term with a density dependence of the potential term proportional to rho/rho_0^gamma with gamma = 0.9 +- 0.4.

  1. Variational energy principle for compressible, baroclinic flow. 2: Free-energy form of Hamilton's principle

    NASA Technical Reports Server (NTRS)

    Schmid, L. A.

    1977-01-01

    The first and second variations are calculated for the irreducible form of Hamilton's Principle that involves the minimum number of dependent variables necessary to describe the kinetmatics and thermodynamics of inviscid, compressible, baroclinic flow in a specified gravitational field. The form of the second variation shows that, in the neighborhood of a stationary point that corresponds to physically stable flow, the action integral is a complex saddle surface in parameter space. There exists a form of Hamilton's Principle for which a direct solution of a flow problem is possible. This second form is related to the first by a Friedrichs transformation of the thermodynamic variables. This introduces an extra dependent variable, but the first and second variations are shown to have direct physical significance, namely they are equal to the free energy of fluctuations about the equilibrium flow that satisfies the equations of motion. If this equilibrium flow is physically stable, and if a very weak second order integral constraint on the correlation between the fluctuations of otherwise independent variables is satisfied, then the second variation of the action integral for this free energy form of Hamilton's Principle is positive-definite, so the action integral is a minimum, and can serve as the basis for a direct trail and error solution. The second order integral constraint states that the unavailable energy must be maximum at equilibrium, i.e. the fluctuations must be so correlated as to produce a second order decrease in the total unavailable energy.

  2. THE EVALUATION OF AN AXIAL FLOW, LIFT TYPE TURBINE FOR HARNESSING THE KINETIC ENERGY IN A TIDAL FLOW

    Microsoft Academic Search

    W. J. Swenson

    The paper covers the evaluation of an axial flow lift type turbine carried out as part of the research to determine the feasibility of developing a kinetic energy tidal power generator. The evaluation was carried out on a test unit deployed at a site with a relatively high water velocity. The first turbine evaluated was an axial flow drag type

  3. Energy Flow and Group Velocity of Electromagnetic Surface Wave in Hydrodynamic Approximation

    Microsoft Academic Search

    Etsuo Matsuo; Mikio Tsuji

    1978-01-01

    Expressions for the energy density and the energy flow are derived for the electromagnetic surface wave (surface plasmon) on a semi-infinite metal surface by using the hydrodynamic approximation. A proof is given for the equality between the group velocity and the energy velocity. It is also shown that the direction of the energy flow in the metal is the same

  4. Energy Analysis of Flow Induced Harmonic Motion in Blood Vessel Walls

    Microsoft Academic Search

    Istvan Horvath; David J. Foran; Frederick H. Silver

    2005-01-01

    Energy is transferred between the flowing blood and the vessel walls during pulsatile blood flow (a normal pulse cycle) resulting in storage and dissipation of elastic energy. This allows the elastic and muscular arteries to act as an auxiliary pump to propel the blood fluid forward during systole and maintain a basal blood pressure during diastole. The pulsatile flow pattern

  5. Bayesian Modeling of Perceived Surface Slant from Actively-Generated and Passively-Observed Optic Flow

    Microsoft Academic Search

    Corrado Caudek; Carlo Fantoni; Fulvio Domini; Hans P. Op. de Beeck

    2011-01-01

    We measured perceived depth from the optic flow (a) when showing a stationary physical or virtual object to observers who moved their head at a normal or slower speed, and (b) when simulating the same optic flow on a computer and presenting it to stationary observers. Our results show that perceived surface slant is systematically distorted, for both the active

  6. ACTIVE VORTICAL FLOW CONTROL FOR ALLEVIATION OF TWIN-TAIL BUFFET OF GENERIC FIGHTER AIRCRAFT

    Microsoft Academic Search

    E. F. SHETA; V. J. HARRAND; L. J. HUTTSELL

    2001-01-01

    A multidisciplinary computational investigation has been conducted to examine the feasibility of controlling the buffet problem using different active flow control methods. Tangential central blowing (TCB), tangential vortex blowing (TVB), and tangential spanwise blowing (TSB) methods were used to inject high-momentum fluid into the vortical flow of generic fighter aircraft flying at 30° angle of attack. The effect of blowing

  7. Hydrothermal fluid flow within a tectonically active rift-ridge transform junction: Tjörnes Fracture Zone, Iceland

    Microsoft Academic Search

    M. Lupi; S. Geiger; C. M. Graham

    2010-01-01

    We investigate the regional fluid flow dynamics in a highly faulted transform area, the Tjörnes Fracture Zone in northern Iceland which is characterized by steep geothermal gradients, hydrothermal activity, and strong seismicity. We simulate fluid flow within the Tjörnes Fracture Zone using a high-resolution model that was based on the available geological and geophysical data and has the aim to

  8. Potentiometric flow injection determination of amylase activity by using hexacyanoferrate(III)-hexacyanoferrate(II) potential buffer

    Microsoft Academic Search

    Hiroki Ohura; Toshihiko Imato; Yasukazu Asano; Sumio Yamasaki

    1998-01-01

    A highly sensitive potentiometric flow injection determination of amylase activity was carried out, utilizing a redox reaction of hexacyanoferrate(III) in alkaline media with reducing sugar as product of the enzymatic hydrolysis reaction of starch with amylase. The analytical method is based on the potential change detection of a flow-through type redox electrode detector due to the composition change of a

  9. American Institute of Aeronautics and Astronautics Microjet Based Active Flow Control on a Fixed Wing UAV

    E-print Network

    . Since PIV cannot be conducted on the UAV during flight, tufts were installed to the aircraft to serve of active flow and noise control applications. These actuators are capable of reducing oscillations disturbances in supersonic impinging jets2 , and delaying/eliminating flow separation induced by adverse

  10. Vibration signal classification by wavelet packet energy flow manifold learning

    NASA Astrophysics Data System (ADS)

    He, Qingbo

    2013-04-01

    This paper proposes a new study to explore the wavelet packet energy (WPE) flow characteristics of vibration signals by using the manifold learning technique. This study intends to discover the nonlinear manifold information from the WPE flow map of vibration signals to characterize and discriminate different classes. A new feature, called WPE manifold feature, is achieved by three main steps: first, the wavelet packet transform (WPT) is conducted to decompose multi-class signals into a library of time-frequency subspaces; second, the WPE is calculated in each subspace to produce a feature vector for each signal; and finally, low-dimensional manifold features carrying class information are extracted from the WPE library for either training or testing samples by using the manifold learning algorithm. The new feature reveals the nonlinear WPE flow structure among various redundant time-frequency subspaces. It combines the benefits of time-frequency characteristics and nonlinear information, and hence exhibits valuable properties for vibration signal classification. The effectiveness and the merits of the proposed method are confirmed by case studies on vibration analysis-based machine fault classification.

  11. Observations of subsonic and supersonic shear flows in laser driven high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Harding, E. C.

    2009-11-01

    Shear layers containing strong velocity gradients appear in many high-energy-density (HED) systems and play important roles in mixing and the transition to turbulence. Yet few laboratory experiments have been carried out to study their detailed evolution in this extreme environment where plasmas are compressible, actively ionizing, often involve strong shock waves and have complex material properties. Many shear flows produce the Kelvin-Helmholtz (KH) instability, which initiates the mixing at a fluid interface. We present results from two dedicated shear flow experiments that produced overall subsonic and supersonic flows using novel target designs. In the subsonic case, the Omega laser was used to drive a blast wave along a rippled interface between plastic and foam, shocking both the materials to produce two fluids separated by a sharp shear layer. The interface subsequently rolled-upped into large KH vortices that were accompanied by bubble-like structures of unknown origin. This was the first time the evolution of a well-resolved KH instability was observed in a HED plasma in the laboratory. We have analyzed the properties and dynamics of the plasma based on the data and fundamental models, without resorting to simulated values. In the second, supersonic experiment the Nike laser was used to drive a supersonic flow of Al plasma along a rippled, low-density foam surface. Here again the flowing plasma drove a shock into the second material, so that two fluids were separated by a shear layer. In contrast to the subsonic case, the flow developed shocks around the ripples in response to the supersonic flow of Al. Collaborators: R.P. Drake, O.A. Hurricane, J.F. Hansen, Y. Aglitskiy, T. Plewa, B.A. Remington, H.F. Robey, J.L. Weaver, A.L. Velikovich, R.S. Gillespie, M.J. Bono, M.J. Grosskopf, C.C. Kuranz, A. Visco.

  12. Energy Management and RD & D Activities for Energy Conservation in TEPCO 

    E-print Network

    Ohmori, M.; Yoshihama, K.

    1981-01-01

    The followings are mentioned on the experiences and results through performance of energy management and RD & D activities for energy conservation in TEPCO. - Public Relations and Energy Audit Activities. - RD & D Activities (1) Demand...

  13. Energy Expenditure During Extravehicular Activity Through Apollo

    NASA Technical Reports Server (NTRS)

    Paul, Heather L.

    2012-01-01

    Monitoring crew health during manned space missions has always been an important factor to ensure that the astronauts can complete the missions successfully and within safe physiological limits. The necessity of real-time metabolic rate monitoring during extravehicular activities (EVAs) came into question during the Gemini missions, when the energy expenditure required to complete EVA tasks exceeded the life support capabilities for cooling and humidity control and, as a result, crew members ended the EVAs fatigued and overworked. This paper discusses the importance of real-time monitoring of metabolic rate during EVAs, and provides a historical look at energy expenditure during EVAs through the Apollo Program.

  14. Energy Expenditure During Extravehicular Activity Through Apollo

    NASA Technical Reports Server (NTRS)

    Paul, Heather L.

    2011-01-01

    Monitoring crew health during manned space missions has always been an important factor to ensure that the astronauts can complete the missions successfully and within safe physiological limits. The necessity of real-time metabolic rate monitoring during extravehicular activities (EVAs) came into question during the Gemini missions, when the energy expenditure required to complete EVA tasks exceeded the life support capabilities for cooling and humidity control and crewmembers (CMs) ended the EVAs fatigued and overworked. This paper discusses the importance of real-time monitoring of metabolic rate during EVA, and provides a historical look at energy expenditure during EVA through the Apollo program.

  15. Subsurface Flows Near Active Regions and Filaments as Determined by Local Helioseismology

    NASA Astrophysics Data System (ADS)

    Haber, D. A.

    Subsurface flows, determined by local-helioseismic techniques such as time-distance tomography, ring analysis, and acoustic holography, are often stronger and more organized near magnetic activity than in areas of quiet Sun. Markedly different behavior is seen depending on the strength of magnetic activity and depth of observed flows. On the larger scales generally used by ring-analysis techniques, converging flows are seen near the surface around most active regions, while diverging flows are seen below 10 Mm for the largest complexes. On smaller scales --- those used mainly by time-distance tomography, acoustic holography, and high-resolution ring analysis --- diverging moat flows are observed in the near-surface layers around sunspots. This paper is a review of what we have learned so far about long-lasting flows (? 8h) in and around active regions, as determined by the various local helioseismic techniques, as well as how these flows may influence magnetic structures and activity higher in the solar atmosphere.

  16. Misperception of rigidity from actively generated optic flow.

    PubMed

    Fantoni, Carlo; Caudek, Corrado; Domini, Fulvio

    2014-01-01

    It is conventionally assumed that the goal of the visual system is to derive a perceptual representation that is a veridical reconstruction of the external world: a reconstruction that leads to optimal accuracy and precision of metric estimates, given sensory information. For example, 3-D structure is thought to be veridically recovered from optic flow signals in combination with egocentric motion information and assumptions of the stationarity and rigidity of the external world. This theory predicts veridical perceptual judgments under conditions that mimic natural viewing, while ascribing nonoptimality under laboratory conditions to unreliable or insufficient sensory information--for example, the lack of natural and measurable observer motion. In two experiments, we contrasted this optimal theory with a heuristic theory that predicts the derivation of perceived 3-D structure based on the velocity gradients of the retinal flow field without the use of egomotion signals or a rigidity prior. Observers viewed optic flow patterns generated by their own motions relative to two surfaces and later viewed the same patterns while stationary. When the surfaces were part of a rigid structure, static observers systematically perceived a nonrigid structure, consistent with the predictions of both an optimal and a heuristic model. Contrary to the optimal model, moving observers also perceived nonrigid structures in situations where retinal and extraretinal signals, combined with a rigidity assumption, should have yielded a veridical rigid estimate. The perceptual biases were, however, consistent with a heuristic model which is only based on an analysis of the optic flow. PMID:24610953

  17. Energy flows in graphene: hot carrier dynamics and cooling.

    PubMed

    Song, Justin C W; Levitov, Leonid S

    2015-04-29

    Long lifetimes of hot carriers can lead to qualitatively new types of responses in materials. The magnitude and time scales for these responses reflect the mechanisms governing energy flows. We examine the microscopics of two processes which are key for energy transport, focusing on the unusual behavior arising due to graphene's unique combination of material properties. One is hot carrier generation in its photoexcitation dynamics, where hot carriers multiply through an Auger type carrier-carrier scattering cascade. The hot-carrier generation manifests itself through elevated electronic temperatures which can be accessed in a variety of ways, in particular optical conductivity measurements. Another process of high interest is electron-lattice cooling. We survey different cooling pathways and discuss the cooling bottleneck arising for the momentum-conserving electron-phonon scattering pathway. We show how this bottleneck can be relieved by higher-order collisions—supercollisions—and examine the variety of supercollision processes that can occur in graphene. PMID:25834944

  18. Wind Tunnel and Flight Testing of Active Flow Control on a UAV 

    E-print Network

    Babbar, Yogesh

    2011-08-08

    WIND TUNNEL AND FLIGHT TESTING OF ACTIVE FLOW CONTROL ON A UAV A Thesis by YOGESH BABBAR Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE May 2010 Major Subject: Aerospace Engineering WIND TUNNEL AND FLIGHT TESTING OF ACTIVE FLOW CONTROL ON A UAV A Thesis by YOGESH BABBAR Submitted to the Office of Graduate Studies of Texas A&M University in partial...

  19. Cross-flow microfiltration of activated sludge using submerged membrane with air bubbling

    Microsoft Academic Search

    Yasutoshi Shimizu; Katsushi Uryu; Yu-Ichi Okuno; Atsuo Watanabe

    1996-01-01

    For the purpose of developing a wastewater treatment membrane bioreactor system, cross-flow microfiltration of intermittently aerated activated sludge was carried out, as a part of the solid-liquid separation process in the bioreactor. The tubular alumina microfiltration membrane, having a pore size of 0.5 ?m, was submerged in the activated sludge. A cross-flow stream over the membrane surface was produced by

  20. Active Control by Conservation of Energy Concept

    NASA Technical Reports Server (NTRS)

    Maestrello, Lucio

    2000-01-01

    Three unrelated experiments are discussed; each was extremely sensitive to initial conditions. The initial conditions are the beginnings of the origins of the information that nonlinearity displays. Initial conditions make the phenomenon unstable and unpredictable. With the knowledge of the initial conditions, active control requires far less power than that present in the system response. The first experiment is on the control of shocks from an axisymmetric supersonic jet; the second, control of a nonlinear panel response forced by turbulent boundary layer and sound; the third, control of subharmonic and harmonics of a panel forced by sound. In all three experiments, control is achieved by redistribution of periodic energy response such that the energy is nearly preserved from a previous uncontrolled state. This type of active control improves the performance of the system being controlled.

  1. Energy Adventure Center. Activity Book. Revised [and Expanded] Edition.

    ERIC Educational Resources Information Center

    Wichita Unified School District 259, KS.

    A variety of energy activities are provided, including instructions for and questions related to energy films. The activities are organized into five sections. Section 1 (work) includes an activity focusing on movement and change. Section 2 (forms of energy) includes activities related to mechanical (movement), radiant (light), chemical (burning),…

  2. Active Feedback Control of a Web Flutter Using Flow Control Devices

    NASA Astrophysics Data System (ADS)

    Hayashi, Yusuke; Watanabe, Masahiro; Hara, Kensuke

    This paper develops a non-contact active feedback control of web flutter in a narrow passage by using movable plates set at inlet and outlet of the passage. The strategy of this active feedback control is based on the flow-control which cancels the exciting fluid force acting on the web, i.e., cancels the self-excited feedback mechanism. In this paper, suppression of the web flutter by the active feedback control is demonstrated experimentally. In the experiments, a web (film), as a controlled object, is subjected to air flow in a narrow passage. The web flutter occurs to the web in the translational motion over the critical flow velocity. And the web flutter is actively controlled and suppressed by the movable plate motion which changes the air flow in the passage. The critical flow velocity under controlled condition is examined with changing the controller gain and phase-shift between the web motion and the movable plate motion. As a result, it is indicated that the active feedback control increases the critical flow velocity, and suppress the web flutter effectively. Moreover, the control performance is examined experimentally, and stabilization mechanism by the active feedback control is discussed.

  3. Numerical study of active control of mixing in electro-osmotic flows by temperature difference using lattice Boltzmann methods.

    PubMed

    Alizadeh, A; Wang, J K; Pooyan, S; Mirbozorgi, S A; Wang, M

    2013-10-01

    In this paper, the effect of temperature difference between inlet flow and walls on the electro-osmotic flow through a two-dimensional microchannel is investigated. The main objective is to study the effect of temperature variations on the distribution of ions and consequently internal electric potential field, electric body force, and velocity fields in an electro-osmotic flow. We assume constant temperature and zeta potential on walls and use the mean temperature of each cross section to characterize the Boltzmann ion distribution across the channel. Based on these assumptions, the multiphysical transports are still able to be described by the classical Poisson-Boltzmann model. In this work, the Navier-Stokes equation for fluid flow, the Poisson-Boltzmann equation for ion distribution, and the energy equation for heat transfer are solved by a couple lattice Boltzmann method. The modeling results indicate that the temperature difference between walls and the inlet solution may lead to two symmetrical vortices at the entrance region of the microchannel which is appropriate for mixing enhancements. The advantage of this phenomenon for active control of mixing in electro-osmotic flow is the manageability of the vortex scale without extra efforts. For instance, the effective domain of this pattern could broaden by the following modulations: decreasing the external electric potential field, decreasing the electric double layer thickness, or increasing the temperature difference between inlet flow and walls. This work may provide a novel strategy for design or optimization of microsystems. PMID:23859813

  4. An active piezoelectric energy extraction method for pressure energy harvesting

    NASA Astrophysics Data System (ADS)

    Deterre, M.; Lefeuvre, E.; Dufour-Gergam, E.

    2012-08-01

    This paper presents an energy harvesting technique to power autonomous systems and more particularly active implantable medical devices. We employ a piezoelectric diaphragm placed in a fluidic environment such as blood subjected to very low frequency (2 Hz) pressure variations that is deflected in a quasi-static manner and transduces mechanical energy into electrical energy. In order to maximize energy generation and to get the most out of a given piezoelectric device, we propose to apply an optimized method to extract the piezoelectrically generated charge through the application of a controlled voltage. We believe that this method could be one of the improvement levers to achieve self-powered miniaturized implants. An analytical model is presented and shows that within its validity domain, the extracted energy is proportional to the desired applied voltage. Taking power electronics losses into account can yield a theoretical increase in the extracted energy of several thousand per cent. Experimental measurements in a pressure chamber have been carried out whose results corroborate the proposed model. For the tested setup, the application of a 10 V peak amplitude square-wave voltage increased the extracted energy by a factor of nine compared to a classical rectifier-based energy harvesting method.

  5. High energy activation data library (HEAD-2009)

    SciTech Connect

    Mashnik, Stepan G [Los Alamos National Laboratory; Korovin, Yury A [NON LANL; Natalenko, Anatoly A [NON LANL; Konobeyev, Alexander Yu [NON LANL; Stankovskiy, A Yu [NON LANL

    2010-01-01

    A proton activation data library for 682 nuclides from 1 H to 210Po in the energy range from 150 MeV up to 1 GeV was developed. To calculate proton activation data, the MCNPX 2.6.0 and CASCADE/INPE codes were chosen. Different intranuclear cascade, preequilibrium, and equilibrium nuclear reaction models and their combinations were used. The optimum calculation models have been chosen on the basis of statistical correlations for calculated and experimental proton data taken from the EXFOR library of experimental nuclear data. All the data are written in ENDF-6 format. The library is called HEPAD-2008 (High-Energy Proton Activation Data). A revision of IEAF-2005 neutron activation data library has been performed. A set of nuclides for which the cross-section data can be (and were) updated using more modern and improved models is specified, and the corresponding calculations have been made in the present work. The new version of the library is called IEAF-2009. The HEPAD-2008 and IEAF-2009 are merged to the final HEAD-2009 library.

  6. Energy dynamics in a turbulent channel flow using the Karhunen-Loéve approach

    NASA Astrophysics Data System (ADS)

    Webber, G. A.; Handler, R. A.; Sirovich, L.

    2002-12-01

    The dynamical equations for the energy in a turbulent channel flow have been developed by using the Karhunen-Loéve modes to represent the velocity field. The energy balance equations show that all the energy in the flow originates from the applied pressure gradient acting on the mean flow. Energy redistribution occurs through triad interactions, which is basic to understanding the dynamics. Each triad interaction determines the rate of energy transport between source and sink modes via a catalyst mode. The importance of the proposed method stems from the fact that it can be used to determine both the rate of energy transport between modes as well as the direction of energy flow. The effectiveness of the method in determining the mechanisms by which the turbulence sustains itself is demonstrated by performing a detailed analysis of triad interactions occurring during a turbulent burst in a minimal channel flow. The impact on flow modification is discussed.

  7. Numerical studies of the application of active flow control to subsonic and transonic airfoil flows using a synthetic jet actuator

    NASA Astrophysics Data System (ADS)

    Vadillo, Jose L.

    2005-07-01

    Active control of flow over airfoils is currently an area of heightened interest in the aerospace community because of its potential in reducing drag, eliminating separation at high angles of attack, and modulating the aerodynamic forces and moments. We study these possibilities by performing several numerical simulations. Numerical simulations are performed by employing an Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations solver in conjunction with a two-equation Shear-Stress-Transport (SST) turbulence model. In particular, the computations are performed for the following three classes of flows: (1) Subsonic flow past a 24% thick Clark-Y airfoil with a triangular bump on the upper surface with and without a synthetic jet actuator. The goal is to perform numerical simulations of this experimentally observed fluidic modification of airfoil pressure distributions leading to reduced pressure drag. The computations are compared with experiments performed at Georgia Tech. (2) Transonic flow past a NACA64A010 airfoil with a synthetic jet actuator. The goal is to control the shock/boundary layer interaction on the airfoil using a synthetic jet actuator to reduce drag as well to achieve desired modulation of aerodynamic forces and moments. (3) Subsonic flow past a commercial supercritical airfoil leveraging the presence of a Gurney flap with a synthetic jet actuator. The goal is again to improve the aerodynamic performance (increase or maintain lift and reduce drag) by using a synthetic jet actuator integrated in a bump on the pressure surface of the airfoil near the trailing edge. The computations are compared with the experiments performed at Georgia Tech. The computations as well as the experiments show the feasibility of active flow control in reducing the drag of airfoils and in achieving the desired modulation of aerodynamic forces and moments.

  8. Energy and Man's Environment Activity Guide: An Interdisciplinary Teacher's Guide to Energy and Environmental Activities, Section One - Sources of Energy.

    ERIC Educational Resources Information Center

    Jones, John, Ed.

    This publication presents the activities pertaining to the first goal of this activity guide series. The activities in this publication focus primarily on the availability of resources, forms of energy, natural laws, and socioeconomic considerations. These materials are appropriate for middle school and junior high school students. These…

  9. Ambiguous hydraulic heads and 14C activities in transient regional flow.

    PubMed

    Schwartz, Franklin W; Sudicky, Edward A; McLaren, Robert G; Park, Young-Jin; Huber, Matthew; Apted, Mick

    2010-01-01

    A regional flow and transport model is used to explore the implications of significant variability in Pleistocene and Holocene climates on hydraulic heads and (14)C activity. Simulations involve a 39 km slice of the Death Valley Flow System through Yucca Mountain toward the Amargosa Desert. The long-time scale over which infiltration has changed (tens-of-thousands of years) is matched by the large physical extent of the flow system (many tens-of-kilometers). Estimated paleo-infiltration rates were estimated using a juniper pollen percentage that extends from the last interglacial (LIG) period (approximately 120 kyrbp) to present. Flow and (14)C transport simulations show that groundwater flow changes markedly as a function of paleoclimate. At the last glacial maximum (LGM, 21 kyrbp), the recharge to the flow system was about an order-of-magnitude higher than present, and water table was more than 100 m higher. With large basin time constants, flow is complicated because hydraulic heads at a given location reflect conditions of the past, but at another location the flow may reflect present conditions. This complexity is also manifested by processes that depend on flow, for example (14)C transport. Without a model that accounts for the historical transients in recharge for at least the last 20,000 years, there is no simple way to deconvolve the (14)C dates to explain patterns of flow. PMID:20015221

  10. Analysis of energy and carbon flows in the future Norwegian dwelling stock

    Microsoft Academic Search

    Nina Holck Sandberg; Helge Brattebø

    2012-01-01

    A dynamic analysis of future energy and carbon flows (2000–2050) is performed on the aggregated residential building stock in Norway. The basis for the analysis is a dynamic material flow analysis of floor areas and the main building materials. By adding energy intensity assumptions for space heating, water heating, domestic electrical appliances and embodied energy in construction materials, the future

  11. Fluxes and energy dissipation in thermal convection and shear flows

    NASA Astrophysics Data System (ADS)

    Eckhardt, B.; Grossmann, S.; Lohse, D.

    2007-04-01

    We expose analogies between turbulence in a fluid heated from below (Rayleigh-Bénard (RB) flow) and shear flows: The unifying theory for RB flow (see Grossmann S. and Lohse D., J. Fluid Mech., 407 (2000) 27 and subsequent refinements) can be extended to the flow between rotating cylinders (Taylor-Couette flow) and pipe (Poiseuille) flow. We identify "wind" dissipation rates and momentum fluxes that are analogous to the dissipation rate and heat flux in RB flow. The proposed unifying description for the three cases is consistent with the experimental data.

  12. Chemical energy release and dynamics of transitional, reactive shear flows

    NASA Astrophysics Data System (ADS)

    Grinstein, F. F.; Kailasanath, K.

    1992-10-01

    Results are reported from numerical studies of a compressible, subsonic reactive mixing layer, on the the effects of chemical-reaction exothermicity on the shear-layer development, and the dependence of these effects on initial conditions. The model solves the unsteady, conservation equations for mass, momentum, energy, and species concentrations. The convective transport equations are solved using the flux-corrected transport (FCT) algorithm and appropriate inflow and outflow boundary conditions. A one-step, irreversible, Arrhenius chemical reaction rate, and realistic (species- and temperature-dependent) modeling of diffusive transport are coupled with the convective transport using time-step splitting. The system studied consists of nonpremixed coflowing streams, where both the fuel (faster stream, hydrogen) and the oxidizer (slower stream, oxygen) are diluted in nitrogen. To facilitate the analysis of the results the flow is organized by low-level, single-frequency velocity perturbation at the inflow. The simulations show that energy release has the effect of reducing the shear layer growth and the amount of chemical product formed-relative to the corresponding cases for which exothermicity is not accounted for, in qualitative agreement with results from previous investigations. The relative mixing-layer growth reduction becomes more pronounced for larger energy release and lower Re, and is significant in terms of both, Reynolds stress, ?u'v', and the velocity-fluctuation correlation u'v'. In spite of the relatively fast flows studied, for the regimes considered, the results on the initial mixing-layer growth are significantly sensitive to diffusive transport effects-more so in terms of Reynolds stress, than in terms of product formation. With larger energy release here associated to larger free-stream reactant molar fractions c0, the amount of chemical product in absolute terms is found to increase with energy release-but slower than c0, so that the product formation becomes effectively less efficient. The results of the present work highlight the difficulties involved in making general statements about the effects of exothermicity on the mixing-layer growth, indicating that a careful conceptualization of these properties in terms of initial conditions and other characteristic parameters of the reactive systems under study is required.

  13. Dielectric barrier plasma dynamics for active control of separated flows

    SciTech Connect

    Roy, Subrata; Singh, K.P.; Gaitonde, Datta V. [Computational Plasma Dynamics Laboratory, Mechanical Engineering, Kettering University, Flint, Michigan 48504 (United States); Computational Sciences Branch, Air Vehicles Directorate, Air Force Research Laboratory, Wright Patterson AFB, Ohio 45433 (United States)

    2006-03-20

    The dynamics of separation mitigation with asymmetric dielectric barrier discharges is explored by considering the gas flow past a flat plate at an angle of attack. A self-consistent model utilizing motion of electrons, ions, and neutrals is employed to couple the electric force field to the momentum of the fluid. The charge separation and concomitant electric field yield a time-averaged body force which is oriented predominantly downstream, with a smaller transverse component towards the wall. This induces a wall-jet-like feature that effectively eliminates the separation bubble. The impact of several geometric and electrical operating parameters is elucidated.

  14. Vortex-enhanced mixing through active and passive flow control methods

    NASA Astrophysics Data System (ADS)

    Depuru Mohan, N. K.; Greenblatt, D.; Nayeri, C. N.; Paschereit, C. O.; Panchapakesan, N. R.

    2015-03-01

    This study aims to understand the underlying physics of vortex-enhanced mixing through active and passive flow control methods. To find a best flow control method that enhances turbulent mixing through the generation of streamwise vortices, an experimental investigation was carried out to compare active and passive flow control methods of an incompressible axisymmetric jet. For active flow control, the lip of the circular jet was equipped with a single small flap deflected away from the jet stream at an angle of 30° to the jet axis. The flap incorporated a flow control slot through which steady and oscillatory suction were implemented. The active flow control methods require power input to the suction devices. For passive flow control, the lip of the circular jet was equipped with a single small delta tab deflected into the jet stream at an angle of 30° to the jet axis. The chord lengths of the flap and delta tab were one-sixth of the jet diameter. The momentum of jet increased in the case of active flow control by entraining the ambient fluid, whereas momentum decreased in the case of passive flow control. The effect of steady suction saturated for volumetric suction coefficient values greater than 0.82 %. The strength of streamwise vortices generated by the flap were greater than those generated by the delta tab. Steady suction produced positive pressures just downstream of the flow control slot in the central portion of the flap and negative pressures at the flap edges. Oscillatory suction was highly dependent on dimensionless frequency ( F +) based on the distance from the flow control slot to the flap trailing edge; the pressures on the central portion of the flap increased for F + ? 0.11 and then decreased for greater F +; finally attained negative pressures at F + = 0.44. The increase in jet momentum and turbulence intensity, combined with the induced streamwise vorticity, makes steady suction a potential concept for increasing propulsion efficiency through vortex-enhanced mixing. The flow control methods modify the jet flow, which in turn would alter the jet noise spectra.

  15. A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus

    SciTech Connect

    Raustad, Richard A. [Florida Solar Energy Center

    2013-01-01

    This paper provides an overview of the variable refrigerant flow heat pump computer model included with the Department of Energy's EnergyPlusTM whole-building energy simulation software. The mathematical model for a variable refrigerant flow heat pump operating in cooling or heating mode, and a detailed model for the variable refrigerant flow direct-expansion (DX) cooling coil are described in detail.

  16. A comparison of energy flow in micelle and vesicle structures.

    PubMed

    Pratama, Fredy; Blanchard, G J

    2015-02-19

    We have investigated the vibrational population relaxation dynamics and state-dependent orientational relaxation behavior of perylene in micelles and vesicles formed using the same amphiphile(s). Decanoic acid and its conjugate base sodium decanoate can form either micelle or vesicle structures in aqueous solution depending on amphiphile concentration and solution pH. The issue of interest in this work is whether or not different assemblies of a given amphiphile manifest different efficiencies with the dissipation of energy. Vibrational population relaxation data show that initial energy flow from the chromophore to the amphiphile aliphatic chains is more efficient in micelles than in vesicles. Longer time scale relaxation, gauged by transient local heating induced by the dissipation of excess energy from perylene shows that the local environment formed by micelles experiences greater temperature change than the local environment formed by vesicles. This finding suggests that the strength of coupling between the bath and the amphiphiles differs for the two structural motifs. PMID:25601286

  17. Nonequilibrium velocity fluctuations and energy amplification in planar Couette flow

    NASA Astrophysics Data System (ADS)

    Ortiz de Zárate, José M.; Sengers, Jan V.

    2009-04-01

    In this paper we investigate intrinsic thermally excited nonequilibrium velocity fluctuations in laminar planar Couette flow. For this purpose we have complemented the solution of the stochastic Orr-Sommerfeld equation for the intensity of the fluctuations of the wall-normal velocity, presented in a previous publication, with a solution of the stochastic Squire equation for the intensity of the fluctuations of the wall-normal vorticity. We have obtained exact solutions of these equations without boundary conditions and solutions in a Galerkin approximation when appropriate boundary conditions are included. These results enable us to make a quantitative assessment of the intensity of these nonequilibrium fluctuations, as well as of the related energy amplification, which are always present, even in the absence of any externally imposed noise.

  18. Nonequilibrium velocity fluctuations and energy amplification in planar Couette flow.

    PubMed

    Ortiz de Zárate, José M; Sengers, Jan V

    2009-04-01

    In this paper we investigate intrinsic thermally excited nonequilibrium velocity fluctuations in laminar planar Couette flow. For this purpose we have complemented the solution of the stochastic Orr-Sommerfeld equation for the intensity of the fluctuations of the wall-normal velocity, presented in a previous publication, with a solution of the stochastic Squire equation for the intensity of the fluctuations of the wall-normal vorticity. We have obtained exact solutions of these equations without boundary conditions and solutions in a Galerkin approximation when appropriate boundary conditions are included. These results enable us to make a quantitative assessment of the intensity of these nonequilibrium fluctuations, as well as of the related energy amplification, which are always present, even in the absence of any externally imposed noise. PMID:19518334

  19. A Wide-Range Active and Reactive Power Flow Controller for a Solid Oxide Fuel Cell Power Conditioning System

    Microsoft Academic Search

    Sung-Yeul Park; Chien-Liang Chen; Jih-Sheng Jason Lai

    2008-01-01

    A wide-range active and reactive power flow controller is designed to operate the inverter in pure leading, pure lagging, and the mix with active and reactive power conditions. The key to achieving lagging power flow control is to ensure sufficiently high enough DC bus voltage to avoid duty cycle saturation. The key to achieving precision power flow control for a

  20. Energy and power limits for microbial activity

    NASA Astrophysics Data System (ADS)

    LaRowe, D.; Amend, J.

    2014-12-01

    The goal of this presentation is to describe a quantitative framework for determining how energy limits microbial activity, biomass and, ultimately, biogeochemical processes. Although this model can be applied to any environment, its utility is demonstrated in marine sediments, which are an attractive test habitat because they encompass a broad spectrum of energy levels, varying amounts of biomass and are ubiquitous. The potential number of active microbial cells in Arkonas Basin (Baltic Sea) sediments are estimated as a function of depth by quantifying the amount of energy that is available to them and the rate at which it is supplied: power. The amount of power supplied per cubic centimeter of sediment is determined by calculating the Gibbs energy of fermentation and sulfate reduction in combination with the rate of particulate organic carbon, POC, degradation. The Reactive Continuum Model (Boudreau and Ruddick, 1991), RCM, is used to determine the rate at which POC is made available for microbial consumption. The RCM represents POC as containing a range of different types of organic compounds whose ability to be consumed by microorganisms varies as a function of the age of the sediment and on the distribution of compound types that were initially deposited. The sediment age model and RCM parameters determined by (Mogollon et al., 2012) are used. The power available for fermentation and sulfate reduction coupled to H2 and acetate oxidation varies from 10-8 W cm-3 at the sediment water interface to between 10-11 - 10-12 W cm-3 at 3.5 meters below the seafloor, mbsf. Using values of maintenance powers for each of these catabolic activities taken from the literature, the total number of active cells in these sediments similarly decreases from just less than 108 cell cm-3 at the SWI to 4.6 x 104 cells cm-3 at 3.5 mbsf. The number of moles of POC decreases from 2.6 x 10-5 to 9.5 x 10-6, also becoming more recalcitrant with depth. Boudreau, B. P. and Ruddick, B. R. (1991) On a reactive continuum representation of organic matter diagenesis. Amer. J. Sci. 291, 507-538. Mogollon, J. M., Dale, A. W., Fossing, H. and Regnier, P. (2012) Timescales for the development of methanogenesis and free gas layers in recently-deposited sediments of Arkona Bason (Baltic Sea). Biogeosciences 9, 1915-1933.

  1. Pigouvian taxation of energy for flow and stock externalities and strategic, noncompetitive energy pricing

    SciTech Connect

    Wirl, F. (Technical Univ. of Vienna (Austria))

    1994-01-01

    The literature on energy and carbon taxes is by and large concerned about the derivation of (globally) efficient strategies. In contrast, this paper considers the dynamic interactions between cartelized energy suppliers and a consumers' government that collectively taxes energy carriers for Pigouvian motives. Two different kinds of external costs are associated with energy consumption: flow (e.g., acid rain) and stock externalities (e.g., global warming). The dynamic interactions between a consumers' government and a producers' cartel are modeled as a differential game with a subgame perfect Nash equilibrium in linear and nonlinear Markov strategies. The major implications are that the nonlinear solutions are Pareto-inferior to the linear strategies and energy suppliers may preempt energy taxation and thereby may raise the price at front; however, this effect diminishes over time because the producers' price declines, while taxes increase. 22 refs., 5 figs., 1 tab.

  2. Activation of G proteins mediates flow-induced prostaglandin E2 production in osteoblasts

    NASA Technical Reports Server (NTRS)

    Reich, K. M.; McAllister, T. N.; Gudi, S.; Frangos, J. A.

    1997-01-01

    Interstitial fluid flow may play a role in load-induced bone remodeling. Previously, we have shown that fluid flow stimulates osteoblast production of cAMP inositol trisphosphate (IP3), and PGE2. Flow-induced increases in cAMP and IP3 were shown to be a result of PG production. Thus, PGE2 production appears to be an important component in fluid flow induced signal transduction. In the present study, we investigated the mechanism of flow-induced PGE2 synthesis. Flow-induced a 20-fold increase in PGE2 production in osteoblasts. Increases were also observed with ALF4-(10mM) (98-fold), an activator of guanidine nucleotide-binding proteins (G proteins), and calcium ionophore A23187 (2 microM) (100-fold) in stationary cells. We then investigated whether flow stimulation is mediated by G proteins and increases in intracellular calcium. Flow-induced PGE2 production was inhibited by the G protein inhibitors GDP beta S (100 microM) and pertussis toxin (1 microgram/ml) by 83% and 72%, respectively. Chelation of extracellular calcium by EGTA (2 mM) and intracellular calcium by quin-2/AM (30 microM) blocked flow stimulation by 87% and 67%, respectively. These results suggest that G proteins and calcium play an important role in mediating mechanochemical signal transduction in osteoblasts.

  3. Energy Conservation Activities for the Classroom K-12.

    ERIC Educational Resources Information Center

    Kentucky Dept. of Energy, Frankfort.

    After a brief introduction entitled "Where Does the Energy We Use Come From," this unit presents 86 activities. Each activity gives the title, concept, objectives, subject area, level, time involved, materials needed, procedures, and related career activities. Topics cover everything from housing insulation to alternate sources of energy to energy

  4. Thermally activated flux flow and fluctuation conductivity in LiFeAs single crystal

    NASA Astrophysics Data System (ADS)

    Song, Yoo Jang; Kang, Byeongwon; Rhee, Jong-Soo; Kwon, Yong Seung

    2012-02-01

    The thermally activated flux flow (TAFF) of a LiFeAs single crystal was studied in magnetic fields up to 9?T. The thermally activated energy (TAE) was analyzed using a conventional Arrhenius relation and a modified TAFF theory. The modified TAFF method results are in better agreement with experimental data than the Arrhenius ones. Through the analysis of the modified TAFF method, we found that the LiFeAs superconductor is regarded as a three-dimensional (3D) system in the TAFF region. In addition, we obtained the vortex-glass temperature Tg from the linear region of the (dln??/dT)- 1. And the fluctuation conductivity was analyzed for the LiFeAs superconductor using Aslamazov-Larkin (AL) theory and the lowest Landau level (LLL) scaling, in zero and nonzero magnetic fields. With the determined values of Tc(H), the fluctuation conductivity was scaled within a 3D-LLL approach. Compared with the NMR result of the 2D antiferromagnetic spin fluctuation, these results imply that LiFeAs exhibited a 2D-3D crossover of the fluctuation conductivity (FC) with decreasing temperature.

  5. Calculation of Activation Energy in Multiphase Reaction

    NASA Astrophysics Data System (ADS)

    Chou, Kuo-Chih; Zhang, Guo-Hua

    2012-06-01

    Most of reactions in the metallurgy are heterogeneous that have a complicated mechanism, for which the kinetic treatment is complex. In general, one has to find the controlling step first, and based on which to derive the corresponding kinetic formula to describe the kinetic behavior. Currently, the most popular method to determine the controlling step is so called the Sharp method, that is, deriving a series of formulae based on different assumed controlling steps in a consecutive heterogeneous reaction, then comparing the experimental data with various kinds of formulae to decide which formula can meet the experiment data well, and from which to select the most suitable controlling step. Nevertheless, because all these formulae used in estimating the controlling step involve some unknown parameters, for instance, the Jander equation, Gingstling-Brounshtein equation, parabolic equation… etc. all involve an unknown parameter "k", that will prevent us from obtaining an accurate activation energy. In this article, we will give a new method based on our series of new formulae concerning the kinetics of multiphase reactions, in which all parameters contained have clear physical meanings, therefore, when they have been used to fit the experimental data, one can obtain a more accurate activation energy and the least relative errors. Some examples have been presented to show the advantages of this new method.

  6. Effect of local energy supply to a hypersonic flow on the drag of bodies with different nose bluntness

    SciTech Connect

    Borzov, V.Yu.; Rybka, I.V.; Yur`ev, A.S. [A.F. Mozhaisky Military Space Engineering Academy, St. Petersburg (Russian Federation)

    1995-06-01

    Parameters of the axisymmetric flow around bodies with different bluntness are compared in the case of constant energy supply to the main hypersonic flow. Flow structures, drag coefficients, and expenditure of energy on overcoming drag are analyzed with the effect of thermal energy on the flow taken into account for different bodies with equal volume.

  7. Closed Loop Active Flow Separation Detection and Control in a Multistage Compressor

    NASA Technical Reports Server (NTRS)

    Bright, Michelle M.; Culley, Dennis E.; Braunscheidel, Edward P.; Welch, Gerard E.

    2005-01-01

    Active closed loop flow control was successfully demonstrated on a full annulus of stator vanes in a low speed axial compressor. Two independent methods of detecting separated flow conditions on the vane suction surface were developed. The first technique detects changes in static pressure along the vane suction surface, while the second method monitors variation in the potential field of the downstream rotor. Both methods may feasibly be used in future engines employing embedded flow control technology. In response to the detection of separated conditions, injection along the suction surface of each vane was used. Injected mass flow on the suction surface of stator vanes is known to reduce separation and the resulting limitation on static pressure rise due to lowered diffusion in the vane passage. A control algorithm was developed which provided a proportional response of the injected mass flow to the degree of separation, thereby minimizing the performance penalty on the compressor system.

  8. Endothelial Cells Inhibit Flow-Induced Smooth Muscle Cell Migration Role of Plasminogen Activator Inhibitor1

    Microsoft Academic Search

    Eileen M. Redmond; John P. Cullen; Paul A. Cahill; James V. Sitzmann; Steingrimur Stefansson; Daniel A. Lawrence; S. Steve Okada

    Background—The endothelium may play a pivotal role in hemodynamic force-induced vascular remodeling. We investigated the role of endothelial cell (EC) plasminogen activator inhibitor-1 (PAI-1) in modulating flow-induced smooth muscle cell (SMC) migration. Methods and Results—Human SMCs cocultured with or without human ECs were exposed to static (0 mL\\/min) or flow (26 mL\\/min; shear stress 23 dyne\\/cm2) conditions for 24 hours

  9. Gravitational field-flow fractionation for the characterisation of active dry wine yeast

    Microsoft Academic Search

    R Sanz; L Puignou; P Reschiglian; M. T Galceran

    2001-01-01

    Gravitational field-flow fractionation (GrFFF) is applied to the fractionation of active dry wine yeast. An experimental approach to the analysis of the effects that field variation by changing mobile phase composition and flow-rate have on the fractionation process of standard particles (polystyrene) was first developed to further obtain effective fractionation of wine yeast by GrFFF. Scanning electron microscopy and Coulter

  10. Analysis of Active Lava Flows on Kilauea Volcano, Hawaii, Using SIR-C Radar Correlation Measurements

    NASA Technical Reports Server (NTRS)

    Zebker, H. A.; Rosen, P.; Hensley, S.; Mouginis-Mark, P. J.

    1995-01-01

    Precise eruption rates of active pahoehoe lava flows on Kilauea volcano, Hawaii, have been determined using spaceborne radar data acquired by the Space Shuttle Imaging Radar-C (SIR-C). Measurement of the rate of lava flow advance, and the determination of the volume of new material erupted in a given period of time, are among the most important observations that can be made when studying a volcano.

  11. The Limit of Free Magnetic Energy in Active Regions

    NASA Technical Reports Server (NTRS)

    Moore, Ron; Falconer, David; Sterling, Alphonse

    2012-01-01

    By measuring from active-region magnetograms a proxy of the free energy in the active region fs magnetic field, it has been found previously that (1) there is an abrupt upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region fs magnetic flux content, and (2) the free energy is usually near its limit when the field explodes in a CME/flare eruption. That is, explosive active regions are concentrated in a main-sequence path bordering the free-energy ]limit line in (flux content, free-energy proxy) phase space. Here, from measurement of Marshall Space Flight Center vector magnetograms, we find the magnetic condition that underlies the free ]energy limit and the accompanying main sequence of explosive active regions. Using a suitable free ]energy proxy measured from vector magnetograms of 44 active regions, we find that (1) in active regions at and near their free ]energy limit, the ratio of magnetic-shear free energy to the non ]free magnetic energy the potential field would have is approximately 1 in the core field, the field rooted along the neutral line, and (2) this ratio is progressively less in active regions progressively farther below their free ]energy limit. This shows that most active regions in which this core-field energy ratio is much less than 1 cannot be triggered to explode; as this ratio approaches 1, most active regions become capable of exploding; and when this ratio is 1 or greater, most active regions are compelled to explode. From these results we surmise the magnetic condition that determines the free ]energy limit is the ratio of the free magnetic energy to the non-free energy the active region fs field would have were it completely relaxed to its potential ]field configuration, and that this ratio is approximately 1 at the free-energy limit and in the main sequence of explosive active regions.

  12. Numerical model for the flow within the tower of a tornado-type wind energy system

    SciTech Connect

    Ayad, S.S.

    1981-11-01

    A two-equation turbulence model is used to predict numerically the flow within the tower of a tornado-type wind energy system. Calculations are carried out for a tower in a uniform flow. Both cases of closed-bottom tower and simulated turbine flow with a variety of turbine-to-tower diameter ratios and turbine flow rates are considered. Calculated values of pressure for closed-bottom tower are compared with experimental values. 11 refs.

  13. Efficient Ionization Investigation for Flow Control and Energy Extraction

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Kamhawi, Hani; Blankson, Isaiah M.

    2009-01-01

    Nonequilibrium ionization of air by nonthermal means is explored for hypersonic vehicle applications. The method selected for evaluation generates a weakly ionized plasma using pulsed nanosecond, high-voltage discharges sustained by a lower dc voltage. These discharges promise to provide a means of energizing and sustaining electrons in the air while maintaining a nearly constant ion/neutral molecule temperature. This paper explores the use of short approx.5 nsec, high-voltage approx.12 to 22 kV, repetitive (40 to 100 kHz) discharges in generating a weakly ionized gas sustained by a 1 kV dc voltage in dry air at pressures from 10 to 80 torr. Demonstrated lifetimes of the sustainer discharge current approx.10 to 25 msec are over three orders of magnitude longer than the 5 nsec pulse that generates the electrons. This life is adequate for many high speed flows, enabling the possibility of exploiting weakly ionized plasma phenomena in flow-fields such as those in hypersonic inlets, combustors, and nozzles. Results to date are obtained in a volume of plasma between electrodes in a bell jar. The buildup and decay of the visible emission from the pulser excited air is photographed on an ICCD camera with nanosecond resolution and the time constants for visible emission decay are observed to be between 10 to 15 nsec decreasing as pressure increases. The application of the sustainer voltage does not change the visible emission decay time constant. Energy consumption as indicated by power output from the power supplies is 194 to 669 W depending on pulse repetition rate.

  14. The material and energy flow through the abrasive waterjet machining and recycling processes

    E-print Network

    Kurd, Michael Omar, 1982-

    2004-01-01

    The purpose of this thesis was to investigate the material and energy flow through the abrasive waterjet machine and the WARD recycling machine. The goal was to track all of the material, water, abrasive, energy, air, and ...

  15. Energy and momentum flow in electromagnetic fields and plasma. [solar wind-magnetospheric interaction

    NASA Technical Reports Server (NTRS)

    Parish, J. L.; Raitt, W. J.

    1983-01-01

    The energy momentum tensor for a perfect fluid in a magnetic field is used to predict the momentum density, energy density, momentum flow, and energy flow of the fluid and the electromagnetic field. It is shown that taking the momentum flow from the energy momentum tensor, rather than starting with differential magnetohydrodynamic equations, can produce more accurate results on the basis of magnetic field data. It is suggested that the use of the energy momentum tensor has the potential for application to analysis of data from the more dynamic regions of the solar system, such as the plasma boundaries of Venus, the Jovian ionosphere, and the terrestrial magnetopause.

  16. Measurements of energy distribution and wall temperature in flowing hydrogen microwave plasma systems

    NASA Technical Reports Server (NTRS)

    Chapman, R.; Finzel, M.; Hawley, M. C.

    1985-01-01

    An electrothermal propulsion concept utilizing a microwave plasma system as the mechanism to convert electromagnetic energy into translational energy of the flowing gas is being investigated. A calorimetric experimental system has been designed and built enclosing the microwave plasma system to accurately determine the net energy transferred to the flowing gas. For a flow rate of 8900 micromoles/sec, a pressure of 7.4 torr, and an absorbed power level of 80 W, an energy transfer efficiency of 50 percent has been measured. A heat transfer model that characterizes the energy transfer processes in the plasma is developed. A wall temperature for the plasma system is calculated.

  17. Flows at the Edge of an Active Region: Observation and Interpretation

    NASA Astrophysics Data System (ADS)

    Boutry, C.; Buchlin, E.; Vial, J.-C.; Régnier, S.

    2012-06-01

    Upflows observed at the edges of active regions have been proposed as the source of the slow solar wind. In the particular case of Active Region (AR) 10942, where such an upflow has been already observed, we want to evaluate the part of this upflow that actually remains confined in the magnetic loops that connect AR 10942 to AR 10943. Both active regions were visible simultaneously on the solar disk and were observed by STEREO/SECCHI EUVI. Using Hinode/EIS spectra, we determine the Doppler shifts and densities in AR 10943 and AR 10942 in order to evaluate the mass flows. We also perform magnetic field extrapolations to assess the connectivity between AR 10942 and AR 10943. AR 10943 displays a persistent downflow in Fe XII. Magnetic extrapolations including both ARs show that this downflow can be connected to the upflow in AR 10942. We estimate that the mass flow received by AR 10943 areas connected to AR 10942 represents about 18% of the mass flow from AR 10942. We conclude that the upflows observed on the edge of active regions represent either large-scale loops with mass flowing along them (accounting for about one-fifth of the total mass flow in this example) or open magnetic field structures where the slow solar wind originates.

  18. FLOWS AT THE EDGE OF AN ACTIVE REGION: OBSERVATION AND INTERPRETATION

    SciTech Connect

    Boutry, C.; Buchlin, E.; Vial, J.-C. [Universite Paris Sud, Institut d'Astrophysique Spatiale, UMR8617, 91405 Orsay (France); Regnier, S., E-mail: eric.buchlin@ias.u-psud.fr [Jeremiah Horrocks Institute, University of Central Lancashire, Preston, PR1 2HE (United Kingdom)

    2012-06-10

    Upflows observed at the edges of active regions have been proposed as the source of the slow solar wind. In the particular case of Active Region (AR) 10942, where such an upflow has been already observed, we want to evaluate the part of this upflow that actually remains confined in the magnetic loops that connect AR 10942 to AR 10943. Both active regions were visible simultaneously on the solar disk and were observed by STEREO/SECCHI EUVI. Using Hinode/EIS spectra, we determine the Doppler shifts and densities in AR 10943 and AR 10942 in order to evaluate the mass flows. We also perform magnetic field extrapolations to assess the connectivity between AR 10942 and AR 10943. AR 10943 displays a persistent downflow in Fe XII. Magnetic extrapolations including both ARs show that this downflow can be connected to the upflow in AR 10942. We estimate that the mass flow received by AR 10943 areas connected to AR 10942 represents about 18% of the mass flow from AR 10942. We conclude that the upflows observed on the edge of active regions represent either large-scale loops with mass flowing along them (accounting for about one-fifth of the total mass flow in this example) or open magnetic field structures where the slow solar wind originates.

  19. Automatic management of energy flows of a stand-alone renewable energy with support of hydrogen

    Microsoft Academic Search

    M. Calderón; A. J. Calderón; A. Ramiro; J. F. González

    This work deals with the design and built of an automation system for controlling the electric energy flows that take place at the continuous current bus (DC Bus) of a wind-solar system with support of hydrogen. The automation system is based on a Siemens PLC s7_313C_2DP. This PLC has been equipped with a Micro Memory Card (MMC) of 2 MB

  20. Automatic management of energy flows of a stand-alone renewable energy supply with hydrogen support

    Microsoft Academic Search

    M. Calderón; A. J. Calderón; A. Ramiro; J. F. González

    2010-01-01

    This work deals with the design and construction of an automation system for controlling the electric energy flows that take place at the continuous current bus (DC Bus) of a wind–solar system with hydrogen support. The automation system is based on a Siemens PLC s7_313C_2DP. This PLC was equipped with a Micro Memory Card (MMC) of 2MB in order to

  1. Hot-Film and Hot-Wire Anemometry for a Boundary Layer Active Flow Control Test

    NASA Technical Reports Server (NTRS)

    Lenahan, Keven C.; Schatzman, David M.; Wilson, Jacob Samuel

    2013-01-01

    Unsteady active flow control (AFC) has been used experimentally for many years to minimize bluff-body drag. This technology could significantly improve performance of rotorcraft by cleaning up flow separation. It is important, then, that new actuator technologies be studied for application to future vehicles. A boundary layer wind tunnel was constructed with a 1ft-x-3ft test section and unsteady measurement instrumentation to study how AFC manipulates the boundary layer to overcome adverse pressure gradients and flow separation. This unsteady flow control research requires unsteady measurement methods. In order to measure the boundary layer characteristics, both hot-wire and hot-film Constant Temperature Anemometry is used. A hot-wire probe is mounted in the flow to measure velocity while a hot-film array lays on the test surface to measure skin friction. Hot-film sensors are connected to an anemometer, a Wheatstone bridge circuit with an output that corresponds to the dynamic flow response. From this output, the time varying flow field, turbulence, and flow reversal can be characterized. Tuning the anemometers requires a fan test on the hot-film sensors to adjust each output. This is a delicate process as several variables drastically affect the data, including control resistance, signal input, trim, and gain settings.

  2. Energy management and control of active distribution systems

    NASA Astrophysics Data System (ADS)

    Shariatzadeh, Farshid

    Advancements in the communication, control, computation and information technologies have driven the transition to the next generation active power distribution systems. Novel control techniques and management strategies are required to achieve the efficient, economic and reliable grid. The focus of this work is energy management and control of active distribution systems (ADS) with integrated renewable energy sources (RESs) and demand response (DR). Here, ADS mean automated distribution system with remotely operated controllers and distributed energy resources (DERs). DER as active part of the next generation future distribution system includes: distributed generations (DGs), RESs, energy storage system (ESS), plug-in hybrid electric vehicles (PHEV) and DR. Integration of DR and RESs into ADS is critical to realize the vision of sustainability. The objective of this dissertation is the development of management architecture to control and operate ADS in the presence of DR and RES. One of the most challenging issues for operating ADS is the inherent uncertainty of DR and RES as well as conflicting objective of DER and electric utilities. ADS can consist of different layers such as system layer and building layer and coordination between these layers is essential. In order to address these challenges, multi-layer energy management and control architecture is proposed with robust algorithms in this work. First layer of proposed multi-layer architecture have been implemented at the system layer. Developed AC optimal power flow (AC-OPF) generates fair price for all DR and non-DR loads which is used as a control signal for second layer. Second layer controls DR load at buildings using a developed look-ahead robust controller. Load aggregator collects information from all buildings and send aggregated load to the system optimizer. Due to the different time scale at these two management layers, time coordination scheme is developed. Robust and deterministic controllers are developed to maximize the energy usage from rooftop photovoltaic (PV) generation locally and minimize heat-ventilation and air conditioning (HVAC) consumption while maintaining inside temperature within comfort zone. The performance of the developed multi-layer architecture has been analyzed using test case studies and results show the robustness of developed controller in the presence of uncertainty.

  3. Oklahoma Energy Awareness Education, Energy Education Activities, Grades 4-12.

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Education, Oklahoma City.

    This publication contains energy education activities for grades 4 through 12 and is part of a set of three publications. These activities are organized under five energy concepts: (1) energy is so basic that nothing moves without it; (2) conservation of energy; (3) there are other energy alternatives; (4) society depends on energy; and (5) the…

  4. Theory of materials and energy flow analysis in ecology and economics

    Microsoft Academic Search

    Sangwon Suh

    2005-01-01

    Materials and energy flow analysis (MEFA) has been widely utilized in ecology and economics, occupying unique positions in both disciplines. The various approaches to materials and energy flow analysis in ecology are reviewed, the focus being on the linear network system introduced from input–output economics. After its introduction in the early 1970s, the calculus and system definition for materials and

  5. Material and energy flow through the UK iron and steel sector. Part 1: 1954–1994

    Microsoft Academic Search

    Peter Michaelis; Tim Jackson

    2000-01-01

    This paper reports on a historical materials and energy flow analysis of the UK steel sector. The flow of raw materials, steel, steel products and steel scrap are quantified for the period from 1954 to 1994. On the basis of this analysis, the authors calculate the consumption of exergy (or available energy) associated with the UK steel sector taking into

  6. Process for producing energy from water flowing down a borehole and recovery same

    Microsoft Academic Search

    Daly

    1992-01-01

    This patent describes a system for producing energy from water flow. It comprises: providing a vertical borehole of sufficient depth to convert liquid water to steam through geothermal energy as the water travels theredown; positioning an internal feed pipe into the borehole; providing an air turbine on the upper end of the feed pipe to allow air flowing into the

  7. Coupling of neural activity to blood flow in olfactory glomeruli is mediated by astrocytic pathways

    PubMed Central

    Petzold, Gabor C.; Albeanu, Dinu F.; Sato, Tomokazu F.; Murthy, Venkatesh N.

    2010-01-01

    SUMMARY Functional neuroimaging uses activity-dependent changes in cerebral blood flow to map brain activity, but the contributions of pre- and postsynaptic activity are incompletely understood, as are the underlying cellular pathways. Using intravital multiphoton microscopy, we measured presynaptic activity, postsynaptic neuronal and astrocytic calcium responses, and erythrocyte velocity and flux in olfactory glomeruli during odor stimulation in mice. Odor-evoked functional hyperemia in glomerular capillaries was highly correlated with glutamate release, but did not require local postsynaptic activity. Odor stimulation induced calcium transients in astrocyte endfeet, and an associated dilation of upstream arterioles. Calcium elevations in astrocytes and functional hyperemia depended on astrocytic metabotropic glutamate receptor 5 and cyclooxygenase activation. Astrocytic glutamate transporters also contributed to functional hyperemia through mechanisms independent of calcium rises and cyclooxygenase activation. These local pathways initiated by glutamate account for a large part of the coupling between synaptic activity and functional hyperemia in the olfactory bulb. PMID:18579080

  8. Active flow control for maximizing performance of spark ignited stratified charge engines. Final report

    SciTech Connect

    Fedewa, Andrew; Stuecken, Tom; Timm, Edward; Schock, Harold J.; Shih, Tom-I.P.; Koochesfahani, Manooch; Brereton, Giles

    2002-10-15

    Reducing the cycle-to-cycle variability present in stratified-charge engines is an important step in the process of increasing their efficiency. As a result of this cycle-to-cycle variability, fuel injection systems are calibrated to inject more fuel than necessary, in an attempt to ensure that the engines fire on every cycle. When the cycle-to-cycle variability is lowered, the variation of work per cycle is reduced and the lean operating limit decreases, resulting in increased fuel economy. In this study an active flow control device is used to excite the intake flow of an engine at various frequencies. The goal of this excitation is to control the way in which vortices shed off of the intake valve, thus lowering the cycle-to-cycle variability in the flow field. This method of controlling flow is investigated through the use of three engines. The results of this study show that the active flow control device did help to lower the cycle-to-cycle variability of the in-cylinder flow field; however, the reduction did not translate directly into improved engine performance.

  9. Improved Algorithm for Gradient Vector Flow Based Active Contour Model Using Global and Local Information

    PubMed Central

    Chen, Bingyu; Sun, Mingui; Jia, Wenyan; Yuan, Zhiyong

    2013-01-01

    Active contour models are used to extract object boundary from digital image, but there is poor convergence for the targets with deep concavities. We proposed an improved approach based on existing gradient vector flow methods. Main contributions of this paper are a new algorithm to determine the false part of active contour with higher accuracy from the global force of gradient vector flow and a new algorithm to update the external force field together with the local information of magnetostatic force. Our method has a semidynamic external force field, which is adjusted only when the false active contour exists. Thus, active contours have more chances to approximate the complex boundary, while the computational cost is limited effectively. The new algorithm is tested on irregular shapes and then on real images such as MRI and ultrasound medical data. Experimental results illustrate the efficiency of our method, and the computational complexity is also analyzed. PMID:24223506

  10. Free energy source for flow shear driven instabilities in electron-magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Sundar, Sita; Das, Amita

    2010-04-01

    The paper discusses the free energy source for the flow shear driven instability in the context of electron-magnetohydrodynamic (EMHD) system. In EMHD as the electron flow velocity also corresponds to the current in the system, the flow shear driven instability has often been identified both as the fluid Kelvin-Helmholtz (KH)-like mode and as the current gradient driven sausage and kinklike modes. It has been shown here that the free energy source for the flow shear driven instability is the kinetic energy of the electron flow and the instability is essentially a fluid KH mode. The manuscript also provides interpretations for certain characteristic features, such as existence of a threshold wavenumber along the flow direction, the order of magnitude estimation of the growth rate, etc., from physical considerations.

  11. Isospin effects on pt-differential flow in heavy ion collisions at intermediate energies

    NASA Astrophysics Data System (ADS)

    Bansal, Rubina; Jain, Anupriya; Kumar, Suneel

    2014-10-01

    This paper aims to study the role of isospin degree of freedom in heavy-ion collisions through the transverse momentum (pt), neutron to proton ratio and system mass dependence of pt-differential transverse flow. Our study shows that (pt)-differential transverse flow dependence can act as sensitive probe to study symmetry energy and its density dependence compared to the energy of vanishing flow. Symmetry energy and its density dependence play a dominant role over the isospin-dependence of nucleon-nucleon cross-section at Fermi energy.

  12. Energy Conservation Activity Packet, Grade 5. Revised Edition.

    ERIC Educational Resources Information Center

    Pohlman, Betty; And Others

    This activity notebook for grade 5 is one of a series developed in response to energy conservation. It contains activities that stress an energy conservation ethic and includes many values clarification activities for grade five. The packet is divided into two parts and provides the teacher with background information, concepts and objectives, and…

  13. Energy Around Us. A Fall Activity Packet for Fourth Grade.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on energy uses, energy

  14. Active control of instabilities in laminar boundary-layer flow. Part 1: An overview

    NASA Technical Reports Server (NTRS)

    Joslin, Ronald D.; Erlebacher, Gordon; Hussaini, M. Yousuff

    1994-01-01

    This paper (the first in a series) focuses on using active-control methods to maintain laminar flow in a region of the flow in which the natural instabilities, if left unattended, lead to turbulent flow. The authors review previous studies that examine wave cancellation (currently the most prominent method) and solve the unsteady, nonlinear Navier-Stokes equations to evaluate this method of controlling instabilities. It is definitely shown that instabilities are controlled by the linear summation of waves (i.e., wave cancellation). Although a mathematically complete method for controlling arbitrary instabilities has been developed (but not yet tested), the review, duplication, and physical explanation of previous studies are important steps for providing an independent verification of those studies, for establishing a framework for subsequent work which will involve automated transition control, and for detailing the phenomena by which the automated studies can be used to expand knowledge of flow control.

  15. Controlling ill-behaved flows with active queue management in DiffServ networks

    NASA Astrophysics Data System (ADS)

    Shu, Yantai; Gao, Deyun; Yang, Oliver W. W.; Qi, Lantao

    2003-08-01

    In this paper, we propose a new active queue management mechanism called the RIO-SD (RED IN and OUT with Selective Dropping) to control ill-behaved flows in DiffServ networks. Under this scheme, core routers are not required to maintain per-flow state, and the ill-behaved flows can be identified based on the drop history of the "OUT-profile" virtual queue. Control is effected by placing two pre-filters in front of the "IN-profile" and "OUT-profile" virtual queues respectively. Simulation results indicate that our approach can also improve the performance of other normal flows. Our work demonstrates that our algorithm is robust and simple to use.

  16. Flow instability of a centrifugal pump determined using the energy gradient method

    NASA Astrophysics Data System (ADS)

    Li, Yi; Dong, Wenlong; He, Zhaohui; Huang, Yuanmin; Jiang, Xiaojun

    2015-02-01

    The stability of the centrifugal pump has not been well revealed because of the complexity of internal flow. To analyze the flow characteristics of a centrifugal pump operating at low capacity, methods of numerical simulation and experimental research were adopted in this paper. Characteristics of the inner flow were obtained. Standard k-? turbulence models were used to calculate the inner flow of the pump under off-design conditions. The distribution of the energy gradient function K was obtained by three-dimensional numerical simulation at different flow rates. The relative velocity component was acquired from the absolute velocity obtained in particle image velocimetry. By comparing with experimental results, it was found that flow instability occurs at the position of maximum K. The flow stability reduces with an increasing flow rate. The research results provide a theoretical basis for the optimization design of a centrifugal pump.

  17. Reconstructing spatio-temporal patterns of debris-flow activity using dendrogeomorphological methods

    NASA Astrophysics Data System (ADS)

    Bollschweiler, Michelle; Stoffel, Markus; Ehmisch, Melanie; Monbaron, Michel

    2007-07-01

    Debris flows are a major threat in many parts of the Alps, where they repeatedly cause severe damage to infrastructure and transportation corridors or even loss of life. Nonetheless, the spatial behavior of past debris-flow activity and the analysis of areas affected during particular events have been widely neglected in reconstructions so far. It was therefore the purpose of this study to reconstruct spatio-temporal patterns of past debris flows on a forested cone in the Swiss Alps (Bruchji torrent, Blatten, Valais). The analysis of past events was based on a detailed geomorphic map (1:1000) of all forms related to debris flows as well as on tree-ring series from 401 heavily affected trees ( Larix decidua Mill. and Picea abies (L.) Karst.) growing in or next to deposits. The samples were analyzed and growth disturbances related to debris-flow activity assessed, such as tangential rows of traumatic resin ducts, the onset of reaction wood or abrupt growth suppression or release. In total, 960 growth disturbances were identified in the samples, belonging to 40 different event years between A.D. 1867 and 2005. In addition, the coupling of tree-ring data with the geomorphic map allowed reconstruction of eleven formerly active channels and spatial representation of individual events. Based on our results we believe that before 1935, debris flows preferentially used those channels located in the western part of the cone, whereas the eastern part of the cone remained widely unaffected. The spatial representation of the 40 events also allowed identification of five different spatial patterns for debris flows at the study site.

  18. Energy Conservation Activity Packet, K-2. Revised Edition.

    ERIC Educational Resources Information Center

    Pohlman, Betty; And Others

    This notebook was developed in response to the concern for energy conservation. It contains activities that stress an energy conservation ethic and includes many values clarification activities for grades K-2. The teacher is provided with some background information on energy, an extensive revised teacher's annotated bibliography, and a list of…

  19. Selected Energy Education Activities for Pennsylvania Middle School Grades. Draft.

    ERIC Educational Resources Information Center

    Hack, Nancy; And Others

    These activities are intended to help increase awareness and understanding of the energy situation and to encourage students to become energy conservationists. The document is divided into sections according to discipline area. A final section is devoted to interdisciplinary activities involving several discipline areas integrated with the energy

  20. Active Gaze Control Improves Optic Flow-Based Segmentation and Steering

    Microsoft Academic Search

    Florian Raudies; Ennio Mingolla; Heiko Neumann

    2012-01-01

    An observer traversing an environment actively relocates gaze to fixate objects. Evidence suggests that gaze is frequently directed toward the center of an object considered as target but more likely toward the edges of an object that appears as an obstacle. We suggest that this difference in gaze might be motivated by specific patterns of optic flow that are generated

  1. Blood flow and oxygen delivery to human brain during functional activity: Theoretical modeling and experimental data

    Microsoft Academic Search

    Mark A. Mintun; Brian N. Lundstrom; Abraham Z. Snyder; Andrei G. Vlassenko; Gordon L. Shulman; Marcus E. Raichle

    2001-01-01

    Coupling of cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) in physiologically activated brain states remains the subject of debates. Recently it was suggested that CBF is tightly coupled to oxidative metabolism in a nonlinear fashion. As part of this hypothesis, mathematical models of oxygen delivery to the brain have been described in which disproportionately large increases

  2. Active QoS Flow Maintenance in Robotic, Mobile, Ad Hoc Networks

    E-print Network

    Shenoy, Prashant

    Active QoS Flow Maintenance in Robotic, Mobile, Ad Hoc Networks John D. Sweeney, Roderic Grupen used in ad hoc network research [4], the mobility model in this setting assume that the nodes are able of Massachusetts Amherst {sweeney, grupen, shenoy}@cs.umass.edu Abstract This paper considers a system of mobile

  3. Respiratory muscle activity related to flow and lung volume in preterm infants compared with term infants

    Microsoft Academic Search

    G. J. Hutten; Eykern van L. A; P. Latzin; C. Thamrin; Aalderen van W. M; U. Frey

    2010-01-01

    Infants with chronic lung disease (CLD) have a capacity to maintain functional lung volume despite alterations to their lung mechanics. We hypothesize that they achieve this by altering breathing patterns and dynamic elevation of lung volume, leading to differences in the relationship between respiratory muscle activity, flow and lung volume. Lung function and transcutaneous electromyography of the respiratory muscles (rEMG)

  4. 1. Flow of research activity and information research 2. What are journal articles?

    E-print Network

    Banbara, Mutsunori

    1. Flow of research activity and information research 2. What are journal articles? 3. Keywords & databases --difference between book and journal article-- 4. Let's find articles in article databases 5. How to access article databases --through Kobe university library's web site-- 6. Core article databases

  5. EFFECTS OF FLOW EQUALIZATION ON THE OPERATION AND PERFORMANCE OF AN ACTIVATED SLUDGE PLANT

    EPA Science Inventory

    A plant-scale research program was carried out for more than a year to evaluate the impact of flow equalization on the 14,000 cu m/day (3.7 mgd) upgraded activated sludge plant at Ypsilanti Township, Michigan. Process streams were characterized under both equalized and unequalize...

  6. The Cooling Rate of an Active Aa Lava Flow Determined Using an Orbital Imaging Spectrometer

    Microsoft Academic Search

    Robert Wright; Harold Garbeil

    2010-01-01

    The surface temperature of an active lava flow is an important physical property to measure. Through its influence on lava crystallinity, cooling exerts a fundamental control on lava rheology. Remotely sensed thermal radiance data acquired by multispectral sensors such as Landsat Thematic Mapper and the Terra Advanced Spaceborne Thermal Emission and Reflection Radiometer, are of insufficient spectral and radiometric fidelity

  7. The evolution of an active silicic lava flow field: an ETM+ perspective

    E-print Network

    Rose, William I.

    'i, 2525 Correa Road, Honolulu, HI 96822, USA b INSIVUMEH, 7a Av. 14-57, Zona 13, Guatemala City, Guatemala, Houghton, MI 49931, USA d Santa Maria Volcano Observatory, c/o INSIVUMEH, 7a Av. 14-57, Zona 13, Guatemala City, Guatemala Accepted 5 December 2003 Abstract An active dacitic lava flow began advancing down

  8. Assessing the spatial dynamics of debris-flow activity on a forested cone using dendroecological methods

    E-print Network

    Butler, David R. - Department of Geography, Texas State University

    Assessing the spatial dynamics of debris-flow activity on a forested cone using dendroecological big events may eliminate entire forest stands and therefore render the application approaches ­ dendrogeomorphology and minimum age dating ­ so as to reconstruct the spatial dynamics of past

  9. Tracing Attention and the Activation Flow of Spoken Word Planning Using Eye Movements

    ERIC Educational Resources Information Center

    Roelofs, Ardi

    2008-01-01

    The flow of activation from concepts to phonological forms within the word production system was examined in 3 experiments. In Experiment 1, participants named pictures while ignoring superimposed distractor pictures that were semantically related, phonologically related, or unrelated. Eye movements and naming latencies were recorded. The…

  10. Modeling of Word Translation: Activation Flow from Concepts to Lexical Items

    ERIC Educational Resources Information Center

    Roelofs, Ardi; Dijkstra, Ton; Gerakaki, Svetlana

    2013-01-01

    Whereas most theoretical and computational models assume a continuous flow of activation from concepts to lexical items in spoken word production, one prominent model assumes that the mapping of concepts onto words happens in a discrete fashion (Bloem & La Heij, 2003). Semantic facilitation of context pictures on word translation has been taken to…

  11. REGISTRATION OF MULTIPLE REGIONS DERIVED FROM THE OPTICAL FLOW MODEL AND THE ACTIVE CONTOUR FRAMEWORK

    Microsoft Academic Search

    Xavier Bresson; Nawal Houhou; Meritxell Bach Cuadra; Jean-Philippe Thiran

    In this paper, we present a new paradigm to carry out the non- rigid registration of multiple regions with a dense deformation field derived from the optical flow model and the active contour frame- work. The method can merge different tasks such as registration, segmentation and incorporation of prior knowledge into a single framework. The technique is based on finding

  12. Fluid flow and heat convection studies for actively cooled airframes

    NASA Technical Reports Server (NTRS)

    Mills, A. F.

    1993-01-01

    This report details progress made on the jet impingement - liquid crystal - digital imaging experiment. With the design phase complete, the experiment is currently in the construction phase. In order to reach this phase two design related issues were resolved. The first issue was to determine NASP leading edge active cooling design parameters. Meetings were arranged with personnel at SAIC International, Torrance, CA in order to obtain recent publications that characterized expected leading edge heat fluxes as well as other details of NASP operating conditions. The information in these publications was used to estimate minimum and maximum jet Reynolds numbers needed to accomplish the required leading edge cooling, and to determine the parameters of the experiment. The details of this analysis are shown in Appendix A. One of the concerns for the NASP design is that of thermal stress due to large surface temperature gradients. Using a series of circular jets to cool the leading edge will cause a non-uniform temperature distribution and potentially large thermal stresses. Therefore it was decided to explore the feasibility of using a slot jet to cool the leading edge. The literature contains many investigations into circular jet heat transfer but few investigations of slot jet heat transfer. The first experiments will be done on circular jets impinging on a fiat plate and results compared to previously published data to establish the accuracy of the method. Subsequent experiments will be slot jets impinging on full scale models of the NASP leading edge. Table 1 shows the range of parameters to be explored. Next a preliminary design of the experiment was done. Previous papers which used a similar experimental technique were studied and elements of those experiments adapted to the jet impingement study. Trade-off studies were conducted to determine which design was the least expensive, easy to construct, and easy to use. Once the final design was settled, vendors were contacted to verify that equipment could be obtained to meet our specifications. Much of the equipment required to complete the construction of the experiment has been ordered or received. The material status list is shown in Appendix B.

  13. Pulsed-flow air classification for waste to energy production. Final report

    SciTech Connect

    Peirce, J.J.; Vesilind, P.A.

    1983-09-30

    The development and testing of pulsed-flow air classification for waste-to-energy production are discussed. Standard designs generally permit large amounts of combustible material to escape as reject while producing a fuel that is high in metal and glass contaminants. Pulsed-flow classification is presented as a concept which can avoid both pitfalls. Each aspect of theory and laboratory testing is summarized: particle characteristics, theory of pulsed-flow classification, laboratory testing, and pulsed-flow air classification for waste-to-energy production. Conclusions from the research are summarized.

  14. Determinants of the Choice of Reporting the Direct Method or Indirect Method of Cash Flow from Operating Activities: Malaysian Evidence

    Microsoft Academic Search

    Salleh Hassan; Theo Christopher

    2007-01-01

    This study examines the incentives motivating listed companies in Malaysia to voluntarily choose the Direct Method over the Indirect Method in reporting cash flow from operating (CFO) activities in their 1997 annual financial reports following the adoption of the IAS 7 (Revised) Statement of Cash Flows (SCF), which was used prior to the current standard MASB No. 5 Cash Flow

  15. Dynamic simulation of energy consumption in mixed traffic flow considering highway toll station

    NASA Astrophysics Data System (ADS)

    Qian, Yong-Sheng; Zhang, Xiao-Long; Zeng, Jun-Wei; Shao, Xiao-Ming; Wang, Neng

    2015-01-01

    An improved model of energy consumption including toll station is presented in this paper. Using the model, we study the influences of mixed ratio, the idling energy consumption of vehicle, vehicle peak velocity, dwell time and random deceleration probability on energy consumption of Electronic Toll Collection or Manual Toll Collection mixed traffic flow on single lane under periodic condition. Simulating results indicate that the above five parameters are all increasing functions of total energy consumption, in which the idling energy consumption represents the major amounts with the increase of mixed ratio and occupancy rate. Thus, the existence of toll station has significant effect on the energy consumption of mixed traffic flow.

  16. Energy of eigen-modes in magnetohydrodynamic flows of ideal fluids

    E-print Network

    I. V. Khalzov; A. I. Smolyakov; V. I. Ilgisonis

    2007-12-11

    Analytical expression for energy of eigen-modes in magnetohydrodynamic flows of ideal fluids is obtained. It is shown that the energy of unstable modes is zero, while the energy of stable oscillatory modes (waves) can assume both positive and negative values. Negative energy waves always correspond to non-symmetric eigen-modes -- modes that have a component of wave-vector along the equilibrium velocity. These results suggest that all non-symmetric instabilities in ideal MHD systems with flows are associated with coupling of positive and negative energy waves. As an example the energy of eigen-modes is calculated for incompressible conducting fluid rotating in axial magnetic field.

  17. Coupling nutrient uptake and energy flow in headwater streams

    SciTech Connect

    Mulholland, Patrick J [ORNL; Fellows, Christine [Griffith University, Nathan, Queensland, Australia; Valett, H. Maurice [Virginia Polytechnic Institute and State University (Virginia Tech); Dahm, Cliff [University of New Mexico, Albuquerque; Thomas, Steve [University of Nebraska

    2006-08-01

    Nutrient cycling and energy flow in ecosystems are tightly linked through the metabolic processes of organisms. Greater uptake of inorganic nutrients is expected to be associated with higher rates of metabolism [gross primary production (GPP) and respiration (R)], due to assimilatory demand of both autotrophs and heterotrophs. However, relationships between uptake and metabolism should vary with the relative contribution of autochthonous and allochthonous sources of organic matter. To investigate the relationship between metabolism and nutrient uptake, we used whole-stream and benthic chamber methods to measure rates of nitrate-nitrogen (NO{sub 3}-N) uptake and metabolism in four headwater streams chosen to span a range of light availability and therefore differing rates of GPP and contributions of autochthonous carbon. We coupled whole-stream metabolism with measures of NO{sub 3}-N uptake conducted repeatedly over the same stream reach during both day and night, as well as incubating benthic sediments under both light and dark conditions. NO{sub 3}-N uptake was generally greater in daylight compared to dark conditions, and although day-night differences in whole-stream uptake were not significant, light-dark differences in benthic chambers were significant at three of the four sites. Estimates of N demand indicated that assimilation by photoautotrophs could account for the majority of NO{sub 3}-N uptake at the two sites with relatively open canopies. Contrary to expectations, photoautotrophs contributed substantially to NO{sub 3}-N uptake even at the two closed-canopy sites, which had low values of GPP/R and relied heavily on allochthonous carbon to fuel R.

  18. Chemiluminescence lateral flow immunoassay based on Pt nanoparticle with peroxidase activity.

    PubMed

    Park, Jong-Min; Jung, Ha-Wook; Chang, Young Wook; Kim, Hyung-Seok; Kang, Min-Jung; Pyun, Jae-Chul

    2015-01-01

    A lateral flow immunoassay (LF-immunoassay) with an enhanced sensitivity and thermostability was developed by using Pt nanoparticles with a peroxidase activity. The Pt nanoparticles were synthesized by citrate reduction method, and the peroxidase activity of Pt nanoparticles was optimized by adjusting reaction conditions. The peroxidase activity was estimated by using Michaelis-Menten kinetics model with TMB as a chromogenic substrate. The kinetics parameters of KM and Vmax were calculated and compared with horseradish peroxidase (HRP). The thermal stability of the Pt nanoparticles was compared with horseradish peroxidase (HRP) according to the storage temperature and long-term storage period. The feasibility of lateral flow immunoassay with a chemiluminescent signal band was demonstrated by the detection of human chorionic gonadotropin (hCG) as a model analyte, and the sensitivity was determined to be improved by as much as 1000-fold compared to the conventional rapid test based on colored gold-colloids. PMID:25467480

  19. Estimating activity energy expenditure: how valid are physical activity questionnaires?1-3

    Microsoft Academic Search

    Heather K Neilson; Paula J Robson; Christine M Friedenreich; Ilona Csizmadi

    Activity energy expenditure (AEE) is the modifiable component of total energy expenditure (TEE) derived from all activities, both volitional and nonvolitional. Because AEE may affect health, there is interest in its estimation in free-living people. Physical activity questionnaires (PAQs) could be a feasible approach to AEE estima- tion in large populations, but it is unclear whether or not any PAQ

  20. Femtosecond Chemically Activated Reactions: Concept of Nonstatistical Activation at High Thermal Energies

    E-print Network

    Kim, Sang Kyu

    Femtosecond Chemically Activated Reactions: Concept of Nonstatistical Activation at High Thermal Femtosecond chemical activation of reactions at very high thermal energies, much above the bond energy of reactions have been central to chemical kinetics and dynamics. Ideally, with lasers, one wishes to deposit

  1. Kinetic model for the vibrational energy exchange in flowing molecular gas mixtures. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Offenhaeuser, F.

    1987-01-01

    The present study is concerned with the development of a computational model for the description of the vibrational energy exchange in flowing gas mixtures, taking into account a given number of energy levels for each vibrational degree of freedom. It is possible to select an arbitrary number of energy levels. The presented model uses values in the range from 10 to approximately 40. The distribution of energy with respect to these levels can differ from the equilibrium distribution. The kinetic model developed can be employed for arbitrary gaseous mixtures with an arbitrary number of vibrational degrees of freedom for each type of gas. The application of the model to CO2-H2ON2-O2-He mixtures is discussed. The obtained relations can be utilized in a study of the suitability of radiation-related transitional processes, involving the CO2 molecule, for laser applications. It is found that the computational results provided by the model agree very well with experimental data obtained for a CO2 laser. Possibilities for the activation of a 16-micron and 14-micron laser are considered.

  2. Modeling preferential water flow and solute transport in unsaturated soil using the active region model

    SciTech Connect

    Sheng, F.; Wang, K.; Zhang, R.; Liu, H.H.

    2009-03-15

    Preferential flow and solute transport are common processes in the unsaturated soil, in which distributions of soil water content and solute concentrations are often characterized as fractal patterns. An active region model (ARM) was recently proposed to describe the preferential flow and transport patterns. In this study, ARM governing equations were derived to model the preferential soil water flow and solute transport processes. To evaluate the ARM equations, dye infiltration experiments were conducted, in which distributions of soil water content and Cl{sup -} concentration were measured. Predicted results using the ARM and the mobile-immobile region model (MIM) were compared with the measured distributions of soil water content and Cl{sup -} concentration. Although both the ARM and the MIM are two-region models, they are fundamental different in terms of treatments of the flow region. The models were evaluated based on the modeling efficiency (ME). The MIM provided relatively poor prediction results of the preferential flow and transport with negative ME values or positive ME values less than 0.4. On the contrary, predicted distributions of soil water content and Cl- concentration using the ARM agreed reasonably well with the experimental data with ME values higher than 0.8. The results indicated that the ARM successfully captured the macroscopic behavior of preferential flow and solute transport in the unsaturated soil.

  3. Active Flow Control Techniques for use on Three Dimensional Hemispherical Turrets

    NASA Astrophysics Data System (ADS)

    Shea, Patrick; Wallace, Ryan; Glauser, Mark

    2009-11-01

    Hemispherical turrets have been a topic of considerable interest over the past several decades with studies focusing on airborne optical device applications. Highly three dimensional, turbulent flows develop in the wake of a turret, especially when a flat, optical aperture is in place on the hemisphere. Both open and closed-loop flow control have been successfully applied to this geometry to control the turbulent flow over the aperture, but control of large scale structures in the wake using open-loop flow control have been less effective. Fluctuating loads on the turret, which can induce undesired structural loading, have been attributed to strong, turbulent fluctuations in the velocity of the turret wake. The current work involves developing a more robust active control system (both open and closed-loop using suction based actuators) that will not only allow for the control of the flow over the aperture as Syracuse University is currently studying, but will also allow for control of the large scale flow structures that develop in the wake of a turret.

  4. Properties of Near-surface Flows around Active Regions from Helioseismic Holography

    NASA Astrophysics Data System (ADS)

    Braun, D. C.; Wan, K.

    2011-01-01

    A variety of local-helioseismic analyses have shown ~50 m/s flows converging on active regions (ARs). We have examined the average properties of both the 75 strongest converging and 75 strongest diverging flows present in Carrington rotation CR1988 within the uppermost 3 Mm of the Sun. The flows, averaged over 5 days, were deduced from calibrated helioseismic holography measurements applied to MDI observations of CR1988. Inflows associated with ARs typically have maximum speed of between 20 and 60 m/s at about 3 heliocentric degrees from their centers and fall to zero by a radius of 7 degrees. Similar converging flows, however, are prevalent in the quiet Sun. Outflows of similar spatial extent, but signficantly larger speeds, are present diverging from sunspots (i.e. the moat flows). Many of the converging flows in ARs appear to simply mark the boundaries of the moats while others converge on plage regions. In general, large ARs containing sunspots contain a complex mixture of both inflows and outflows which, aside from sunspot moats, also appear similar in property to convective components of the quiet Sun.

  5. Active Control of Flow Separation and Structural Vibrations of a Wind Turbine Blade

    NASA Astrophysics Data System (ADS)

    Maldonado, Victor; Amitay, Michael; Gressick, William

    2008-11-01

    The feasibility of using arrays of synthetic jet actuators to control flow separation and blade vibrations of a wind turbine blade (S809 airfoil) model was explored in wind tunnel experiments. Using this technique, the global flow field over the finite span blade was altered such that at high angles of attack flow separation was mitigated. This resulted in a significant decrease in the vibration of the blade. In addition, flow control was implemented at low angles of attack using a spanwise distribution of active Gurney flaps, instrumented with synthetic jet actuators. The moments and forces on the blade were measured using a six component wall-mounted load cell. In addition, PIV technique was used to quantify the flow field over the blade. The structural vibrations were quantified using strain gauges, placed near the blade's root, and accelerometers, located near the blade's tip. Using synthetic jets, the flow over the blade was either fully or partially reattached, depending on the angle of attack, the spanwise location along the blade, and the Reynolds number. This resulted in a significant reduction in blade's vibrations, where the amplitude of the tip deflection was found to be proportionally controllable by either changing the momentum coefficient, the number of synthetic jets used, or their driving waveform.

  6. Active control of panel vibrations induced by a boundary layer flow

    NASA Technical Reports Server (NTRS)

    Chow, Pao-Liu

    1995-01-01

    The problems of active and passive control of sound and vibration has been investigated by many researchers for a number of years. However, few of the articles are concerned with the sound and vibration with flow-structure interaction. Experimental and numerical studies on the coupling between panel vibration and acoustic radiation due to flow excitation have been done by Maestrello and his associates at NASA/Langley Research Center. Since the coupled system of nonlinear partial differential equations is formidable, an analytical solution to the full problem seems impossible. For this reason, we have to simplify the problem to that of the nonlinear panel vibration induced by a uniform flow or a boundary-layer flow with a given wall pressure distribution. Based on this simplified model, we have been able to consider the control and stabilization of the nonlinear panel vibration, which have not been treated satisfactorily by other authors. Although the sound radiation has not been included, the vibration suppression will clearly reduce the sound radiation power from the panel. The major research findings are presented in three sections. In section two we describe results on the boundary control of nonlinear panel vibration, with or without flow excitation. Sections three and four are concerned with some analytical and numerical results in the optimal control of the linear and nonlinear panel vibrations, respectively, excited by the flow pressure fluctuations. Finally, in section five, we draw some conclusions from research findings.

  7. Wave energy flow conservation for propagation in inhomogeneous Vlasov--Maxwell equilibria

    SciTech Connect

    Kull, H.J.; Berk, H.L.; Morrison, P.J.

    1989-01-01

    Wave energy flow conservation is demonstrated for Hermitian differential operators that arise in the Vlasov--Maxwell theory for propagation perpendicular to a magnetic field. The energy flow can be related to the bilinear concomitant, for a solution and its complex conjugate, by using the Lagrange identity of the operator. This bilinear form obeys a conservation law and is shown to describe the usual Wentzel--Kramers--Brillouin (WKB) energy flow for asymptotically homogeneous regions. The additivity and lack of uniqueness of the energy flow expression is discussed for a general superposition of waves with real and complex wave-numbers. Furthermore, a global energy conservation theorem is demonstrated for an inhomogeneity in one dimension and generalized reflection and transmission coefficients are thereby obtained.

  8. Spontaneous Flows and Accumulation of Active Particles in Connected Micro-Chambers

    E-print Network

    M. Paoluzzi; R. Di Leonardo; L. Angelani

    2014-12-02

    We numerically study the dynamics of run-and-tumble particles in two confining vessels connected by thin channels. Two dominant dynamical behaviors emerge: (i) an oscillatory pumping state, in which particles alternatively fill the two vessels and (ii) a circulating flow state, dynamically maintaining a near constant population level in the containers when connected by two channels. The narrowness of channels and the out-of-equilibrium nature of the system give rise to accumulation phenomena and long-lived spontaneous flows of active particles.

  9. Influence of ofloxacin on photosystems I and II activities of Microcystis aeruginosa and the potential role of cyclic electron flow.

    PubMed

    Deng, Chunnuan; Pan, Xiangliang; Zhang, Daoyong

    2015-02-01

    Pollution with antibiotics poses a great risk to aquatic ecosystems. Although some toxic effects of antibiotics on photosystem II (PSII) have been documented, their toxicity to photosystem I (PSI) is still unclear. In this study, effects of ofloxacin on activities of both PSI and PSII of Microcystis aeruginosa (Kützing) Kützing were investigated. Exposure to 0.1 mg L(-)(1) ofloxacin led to increases in contents of chlorophyll a and carotenoids and photosynthetic activity of M. aeruginosa. PSI activity and its electron transport were not affected by 0.1 mg L(-)(1) ofloxacin. When M. aeruginosa was exposed to ?10 mg L(-)(1) ofloxacin, the electron transport rates of PSI and PSII, the yield of cyclic electron flow (CEF) and the contribution of linear electron flow (LEF) to PSI decreased whereas Y(NA) (limitation of donor side of PSI) and Y(NO) (the quantum yield of non-regulated energy dissipation in PSII) significantly increased. CEF had a significant contribution to alleviating the inhibitory effect of ofloxacin on PSI of M. aeruginosa treated with low concentrations of ofloxacin. The protective role CEF for tolerance of PSI to the toxicity of ofloxacin decreased with increasing ofloxacin concentration. PMID:25209631

  10. Magnetic Energy and Helicity in Two Emerging Active Regions in the Sun

    NASA Technical Reports Server (NTRS)

    Liu, Y.; Schuck, P. W.

    2012-01-01

    The magnetic energy and relative magnetic helicity in two emerging solar active regions, AR 11072 and AR 11158,are studied. They are computed by integrating over time the energy and relative helicity fluxes across the photosphere. The fluxes consist of two components: one from photospheric tangential flows that shear and braid field lines (shear term), the other from normal flows that advect magnetic flux into the corona (emergence term). For these active regions: (1) relative magnetic helicity in the active-region corona is mainly contributed by the shear term,(2) helicity fluxes from the emergence and the shear terms have the same sign, (3) magnetic energy in the corona (including both potential energy and free energy) is mainly contributed by the emergence term, and(4) energy fluxes from the emergence term and the shear term evolved consistently in phase during the entire flux emergence course.We also examine the apparent tangential velocity derived by tracking field-line footpoints using a simple tracking method. It is found that this velocity is more consistent with tangential plasma velocity than with the flux transport velocity, which agrees with the conclusion by Schuck.

  11. Observation of Forward Shocks and Stagnated Ejecta Driven by High-Energy-Density Plasma Flow

    NASA Astrophysics Data System (ADS)

    Drake, R. P.; Glendinning, S. G.; Estabrook, Kent; Remington, B. A.; McCray, Richard; Wallace, R. J.; Suter, L. J.; Smith, T. B.; Carroll, J. J., III; London, R. A.; Liang, E.

    1998-09-01

    Laboratory studies of hydrodynamic effects driven by a flowing, expanding plasma of high-energy density and high Mach number are reported. The flowing plasma is the ejecta from matter accelerated and heated by an ablative shock. X-ray backlighting diagnoses the structure produced when this plasma impacts low-density foam. We observe the forward shock driven into the foam and the stagnated ejecta which drives a reverse shock into the flow.

  12. Numerical study of the air-flow in an oscillating water column wave energy converter

    Microsoft Academic Search

    J. M. Paixão Conde; L. M. C. Gato

    2008-01-01

    The paper presents a numerical study of the air-flow in a typical pneumatic chamber geometry of an oscillating water column (OWC)-type wave energy converter (WEC), equipped with two vertical-axis air turbines, asymmetrically placed on the top of the chamber. Outwards and inwards, steady and periodic, air-flow calculations were performed to investigate the flow distribution at the turbines’ inlet sections, as

  13. Influence of radionuclide adsorption on detection efficiency and energy resolution for flow-cell radiation detectors

    Microsoft Academic Search

    T. A. DeVol; M. E. Keillor; L. W. Burggraf

    1996-01-01

    Flow-cell and batch test experiments were performed to determine the uranyl ion adsorption onto and\\/or complexation with CaF2:Eu scintillator as a function of pH. The flow-cell experiments were modeled with an energy dispersive Monte Carlo algorithm. At pH 2, the flow-cell and batch tests gave consistent results, detection efficiency ~60% and distribution coefficient (Kd ) ~0.3-0.7 mL\\/g, with the model.

  14. Efficiency of energy separation at compressible gas flow in a planar duct

    NASA Astrophysics Data System (ADS)

    Makarov, M. S.; Makarova, S. N.

    2014-12-01

    The method of energy separation in a high-speed flow proposed by A.I. Leontyev is investigated numerically. The adiabatic compressible gas flow (of a helium-xenon mixture) with a low Prandtl number in a planar narrow duct and a flow with heat exchange in a duct partitioned by a heat-conducting wall are analysed. The temperature recovery factor on the adiabatic wall, degree of cooling the low-speed flow part, temperature efficiency, and the adiabatic efficiency in a duct with heat exchange are estimated. The data are obtained for the first time, which make it possible to compare the efficiency of energy separation in a high-speed flow with the efficiency of similar processes in vortex tubes and other setups of gas-dynamic energy separation.

  15. Efficiency of energy separation at compressible gas flow in a planar duct

    NASA Astrophysics Data System (ADS)

    Makarov, M. S.; Makarova, S. N.

    2013-12-01

    The method of energy separation in a high-speed flow proposed by A.I. Leontyev is investigated numerically. The adiabatic compressible gas flow (of a helium-xenon mixture) with a low Prandtl number in a planar narrow duct and a flow with heat exchange in a duct partitioned by a heat-conducting wall are analysed. The temperature recovery factor on the adiabatic wall, degree of cooling the low-speed flow part, temperature efficiency, and the adiabatic efficiency in a duct with heat exchange are estimated. The data are obtained for the first time, which make it possible to compare the efficiency of energy separation in a high-speed flow with the efficiency of similar processes in vortex tubes and other setups of gas-dynamic energy separation.

  16. NADH augments blood flow in physiologically activated retina and visual cortex

    PubMed Central

    Ido, Yasuo; Chang, Katherine; Williamson, Joseph R.

    2004-01-01

    The mechanism(s) that increase retinal and visual cortex blood flows in response to visual stimulation are poorly understood. We tested the hypothesis that increased transfer of electrons and protons from glucose to cytosolic free NAD+, reducing it to NADH, evoked by increased energy metabolism, fuels redox-signaling pathways that augment flow. The near-equilibrium between free cytosolic NADH/NAD+ and lactate/pyruvate ratios established by lactate dehydrogenase predicts that transfer of additional electrons and protons from injected lactate to NAD+ will augment the elevated blood flows in stimulated retina and cortex, whereas transfer of electrons and protons from NADH to injected pyruvate will attenuate the elevated flows. These predictions were tested and confirmed in rats. Increased flows evoked by stimulation also were prevented by inhibition of nitric oxide synthase. These findings support an important role for cytosolic free NADH in fueling a signaling cascade that increases •NO production, which augments blood flow in photostimulated retina and visual cortex. PMID:14704275

  17. Subgrid-scale energy transfer in the near-wall region of turbulent flows

    Microsoft Academic Search

    Carlos Härtel; Leonhard Kleiser; Friedemann Unger; Rainer Friedrich

    1994-01-01

    Direct numerical simulation databases of turbulent channel and pipe flow have been used in order to assess the energy transfer between resolved and unresolved motions in large-eddy simulations. To this end, the velocity fields are split into three parts: a statistically stationary mean flow, the resolved, and the unresolved turbulent fluctuations. The distinction between the resolved and unresolved motions is

  18. Active Flow Control on Low-Aspect Ratio, Low-Reynolds Number Airfoils

    NASA Astrophysics Data System (ADS)

    Munson, Matthew; Kim, Daegyoum; Dickson, William; Gharib, Morteza

    2008-11-01

    Insect flight observations show high-lift mechanisms that rely on leading-edge vortex stabilization. These processes are intimately coupled to the flapping motion of the insect wing. In fixed wing applications, suitable for micro-air vehicles, active flow control may be capable of providing similar influence over vortex formation and stabilization. Steady and pulsed mass injection strategies are used to explore the open-loop response of both the evolution of the flow structures and the forces experienced by the wing. Flow structures will be quantitatively visualized using Defocused Digital Particle Image Velocimetry (DDPIV) and forces measured via a six-axis balance. Insect flight typically occurs at Reynolds numbers of 10^2 to 10^4, and aspect ratios near three. For this investigation, Reynolds numbers are approximately 10^3. The airfoil models are NACA 0012 profiles with aspect ratio two.

  19. Mitigation of Autoignition Due to Premixing in a Hypervelocity Flow Using Active Wall Cooling

    NASA Technical Reports Server (NTRS)

    Axdahl, Erik; Kumar, Ajay; Wilhite, Alan

    2013-01-01

    Preinjection of fuel on the forebody of an airbreathing vehicle is a proposed method to gain access to hypervelocity flight Mach numbers. However, this creates the possibility of autoignition either near the wall or in the core of the flow, thereby consuming fuel prematurely as well as increasing the amount of pressure drag on the vehicle. The computational fluid dynamics code VULCAN was used to conduct three dimensional simulations of the reacting flow in the vicinity of hydrogen injectors on a flat plate at conditions relevant to a Mach 12 notional flight vehicle forebody to determine the location where autoignition occurs. Active wall cooling strategies were formulated and simulated in response to regions of autoignition. It was found that tangential film cooling using hydrogen or helium were both able to nearly or completely eliminate wall autoignition in the flow domain of interest.

  20. Active-distributed temperature sensing to continuously quantify vertical flow in boreholes

    NASA Astrophysics Data System (ADS)

    Read, T.; Bour, O.; Selker, J. S.; Bense, V. F.; Borgne, T. Le; Hochreutener, R.; Lavenant, N.

    2014-05-01

    We show how a distributed borehole flowmeter can be created from armored Fiber Optic cables with the Active-Distributed Temperature Sensing (A-DTS) method. The principle is that in a flowing fluid, the difference in temperature between a heated and unheated cable is a function of the fluid velocity. We outline the physical basis of the methodology and report on the deployment of a prototype A-DTS flowmeter in a fractured rock aquifer. With this design, an increase in flow velocity from 0.01 to 0.3 m s-1 elicited a 2.5°C cooling effect. It is envisaged that with further development this method will have applications where point measurements of borehole vertical flow do not fully capture combined spatiotemporal dynamics.

  1. Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems

    Microsoft Academic Search

    Tainzhen Hong; Xaiobing Liu

    2009-01-01

    With the current movement toward net zero energy buildings, many technologies are promoted with emphasis on their superior energy efficiency. The variable refrigerant flow (VRF) and ground source heat pump (GSHP) systems are probably the most competitive technologies among these. However, there are few studies reporting the energy efficiency of VRF systems compared with GSHP systems. In this article, a

  2. Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems

    Microsoft Academic Search

    Xiaobing Liu; Tianzhen Hong

    2010-01-01

    With the current movement towards net zero energy buildings, many technologies are promoted with emphasis on their superior energy efficiency. The variable refrigerant flow (VRF) and ground source heat pump (GSHP) systems are probably the most competitive technologies among these. However, there are few studies reporting the energy efficiency of VRF systems compared with GSHP systems. In this article, a

  3. Energy flow and charged particle spectra in deep inelastic scattering at HERA

    Microsoft Academic Search

    I. Abt; T. Ahmed; V. Andreev; S. Aid; B. Andrieu; R.-D. Appuhn; M. Arpagaus; A. Babaev; H. Bärwolff; J. Bán; P. Baranov; E. Barrelet; W. Bartel; U. Bassler; H. P. Beck; H.-J. Behrend; A. Belousov; Ch. Berger; H. Bergstein; G. Bernardi; R. Bernet; G. Bertrand-Coremans; M. Besançon; P. Biddulph; E. Binder; J. C. Bizot; V. Blobel; K. Borras; P. C. Bosetti; V. Boudry; C. Bourdarios; A. Braemer; F. Brasse; U. Braun; W. Braunschweig; V. Brisson; D. Bruncko; L. Büngener; J. Bürger; F. W. Büsser; A. Buniatian; S. Burke; G. Buschhorn; A. J. Campbell; T. Carli; F. Charles; J. Chyla; D. Clarke; A. B. Clegg; M. Colombo; J. A. Coughlan; A. Courau; Ch. Coutures; G. Cozzika; L. Criegee; J. Cvach; S. Dagoret; J. B. Dainton; M. Danilov; A. W. E. Dann; W. D. Dau; M. David; E. Deffur; B. Delcourt; L. Del Buono; M. Devel; A. De Roeck; P. Di Nezza; P. Dingus; C. Dollfus; J. D. Dowell; H. B. Dreis; A. Drescher; J. Duboc; D. Düllmann; O. Dünger; H. Duhm; R. Ebbinghaus; M. Eberle; J. Ebert; T. R. Ebert; G. Eckerlin; V. Efremenko; S. Egli; H. Ehrlichmann; S. Eichenberger; R. Eichler; F. Eisele; E. Eisenhandler; N. N. Ellis; R. J. Ellison; E. Elsen; M. Erdmann; E. Evrard; L. Favart; A. Fedotov; D. Feeken; R. Felst; J. Feltesse; I. F. Fensome; J. Ferencei; F. Ferrarotto; K. Flamm; W. Flauger; M. Fleischer; M. Flieser; G. Flügge; A. Fomenko; B. Fominykh; M. Forbush; J. Formánek; J. M. Foster; G. Franke; E. Fretwurst; P. Fuhrmann; E. Gabathuler; K. Gamerdinger; J. Garvey; J. Gayler; M. Gebauer; A. Gellrich; M. Gennis; H. Genzel; R. Gerhards; L. Godfrey; U. Goerlach; L. Goerlich; N. Gogitidze; M. Goldberg; D. Goldner; A. M. Goodall; I. Gorelov; P. Goritchev; C. Grab; H. Grässler; T. Greenshaw; H. Greif; G. Grindhammer; A. Gruber; C. Gruber; J. Haack; D. Haidt; L. Hajduk; O. Hamon; M. Hampel; E. M. Hanlon; M. Hapke; J. Harjes; R. Haydar; W. J. Haynes; J. Heatherington; V. Hedberg; G. Heinzelmann; R. C. W. Henderson; H. Henschel; R. Herma; I. Herynek; W. Hildesheim; P. Hill; C. D. Hilton; J. Hladký; K. C. Hoeger; M. Höppner; Ph. Huet; H. Hufnagel; N. Huot; M. Ibbotson; H. Itterbeck; M.-A. Jabiol; A. Jacholkowska; C. Jacobsson; M. Jaffre; T. Jansen; L. Jönsson; K. Johannsen; D. P. Johnson; L. Johnson; H. Jung; P. I. P. Kalmus; D. Kant; S. Kazarian; R. Kaschowitz; P. Kasselmann; U. Kathage; H. H. Kaufmann; I. R. Kenyon; S. Kermiche; C. Keuker; C. Kiesling; M. Klein; C. Kleinwort; G. Knies; W. Ko; T. Köhler; H. Kolanoski; F. Kole; S. D. Kolya; V. Korbel; M. Korn; P. Kostka; S. K. Kotelnikov; M. W. Krasny; D. Krücker; U. Krüger; J. P. Kubenka; H. Küster; M. Kuhlen; T. Kurca; J. Kurzhöfer; B. Kuznik; D. Lacour; F. Lamarche; R. Lander; M. P. J. Landon; W. Lange; R. Langkau; P. Lanius; J. F. Laporte; A. Lebedev; A. Leuschner; C. Leverenz; S. Levonian; D. Lewin; Ch. Ley; A. Lindner; G. Lindström; F. Linsel; J. Lipinski; P. Loch; H. Lohmander; G. C. Lopez; D. Lüers; D. Lüke; N. Magnussen; E. Malinovski; S. Mani; P. Marage; J. Marks; R. Marshall; J. Martens; R. Martin; H.-U. Martyn; J. Martyniak; S. Masson; A. Mavroidis; S. J. Maxfield; S. J. McMahon; A. Mehta; K. Meier; D. Mercer; T. Merz; C. A. Meyer; H. Meyer; J. Meyer; S. Mikocki; E. Monnier; F. Moreau; J. Moreels; J. V. Morris; K. Müller; P. Murín; S. A. Murray; V. Nagovizin; B. Naroska; Th. Naumann; P. R. Newman; D. Newton; D. Neyret; H. K. Nguyen; F. Niebergall; C. Niebuhr; R. Nisius; G. Nowak; G. W. Noyes; M. Nyberg; H. Oberlack; U. Obrock; J. E. Olsson; S. Orenstein; F. Ould-Saada; C. Pascaud; G. D. Patel; E. Peppel; S. Peters; H. T. Phillips; J. P. Phillips; Ch. Pichler; W. Pilgram; D. Pitzl; S. Prell; R. Prosi; G. Rädel; F. Raupach; K. Rauschnabel; P. Reimer; S. Reinshagen; P. Ribarics; V. Riech; J. Riedlberger; S. Riess; M. Rietz; S. M. Robertson; P. Robmann; R. Roosen; K. Rosenbauer; A. Rostovtsev; C. Royon; M. Rudowicz; M. Ruffer; S. Rusakov; K. Rybicki; N. Sahlmann; E. Sanchez; D. P. C. Sankey; M. Savitsky; P. Schacht; P. Schleper; W. von Schlippe; C. Schmidt; D. Schmidt; W. Schmitz; A. Schöning; V. Schröder; E. Schuhmann; M. Schulz; B. Schwab; A. Schwind; W. Scobel; U. Seehausen; R. Sell; A. Semenov; V. Shekelyan; I. Sheviakov; H. Shooshtari; L. N. Shtarkov; G. Siegmon; U. Siewert; Y. Sirois; I. O. Skillicorn; P. Smirnov; J. R. Smith; Y. Soloviev; H. Spitzer; M. Steenbock; P. Steffen; R. Steinberg; B. Stella; K. Stephens; J. Stier; U. Stösslein; J. Strachota; U. Straumann; W. Struczinski; J. P. Sutton; R. E. Taylor; V. Tchernyshov; C. Thiebaux; G. Thompson; I. Tichomirov; P. Truöl; J. Turnau; J. Tutas; L. Urban; A. Usik; S. Valkar; A. Valkarova; C. Vallée; P. Van Esch; A. Vartapetian; Y. Vazdik; M. Vecko; P. Verrecchia; R. Vick; G. Villet; E. Vogel; K. Wacker; I. W. Walker; A. Walther; G. Weber; D. Wegener; A. Wegener; H. P. Wellisch; L. R. West; S. Willard; M. Winde; G.-G. Winter; Th. Wolff; L. A. Womersley; A. E. Wright

    1994-01-01

    Global properties of the hadronic final state in deep inelastic scattering events at HERA are investigated. The data are corrected for detector effects and are compared directly with QCD phenomenology. Energy flows in both the laboratory frame and the hadronic centre of mass system and energy-energy correlations in the laboratory frame are presented. Comparing various QCD models, the colour dipole

  4. Linear stability, transient energy growth, and the role of viscosity stratification in compressible plane Couette flow.

    PubMed

    Malik, M; Dey, J; Alam, Meheboob

    2008-03-01

    Linear stability and the nonmodal transient energy growth in compressible plane Couette flow are investigated for two prototype mean flows: (a) the uniform shear flow with constant viscosity, and (b) the nonuniform shear flow with stratified viscosity. Both mean flows are linearly unstable for a range of supersonic Mach numbers (M). For a given M , the critical Reynolds number (Re) is significantly smaller for the uniform shear flow than its nonuniform shear counterpart; for a given Re, the dominant instability (over all streamwise wave numbers, alpha ) of each mean flow belongs to different modes for a range of supersonic M . An analysis of perturbation energy reveals that the instability is primarily caused by an excess transfer of energy from mean flow to perturbations. It is shown that the energy transfer from mean flow occurs close to the moving top wall for "mode I" instability, whereas it occurs in the bulk of the flow domain for "mode II." For the nonmodal transient growth analysis, it is shown that the maximum temporal amplification of perturbation energy, G(max), and the corresponding time scale are significantly larger for the uniform shear case compared to those for its nonuniform counterpart. For alpha=0 , the linear stability operator can be partitioned into L ~ L+Re(2) L(p), and the Re-dependent operator L(p) is shown to have a negligibly small contribution to perturbation energy which is responsible for the validity of the well-known quadratic-scaling law in uniform shear flow: G(t/Re) ~ Re(2). In contrast, the dominance of L(p) is responsible for the invalidity of this scaling law in nonuniform shear flow. An inviscid reduced model, based on Ellingsen-Palm-type solution, has been shown to capture all salient features of transient energy growth of full viscous problem. For both modal and nonmodal instability, it is shown that the viscosity stratification of the underlying mean flow would lead to a delayed transition in compressible Couette flow. PMID:18517526

  5. Energy simulation in the variable refrigerant flow air-conditioning system under cooling conditions

    Microsoft Academic Search

    Y. P. Zhou; J. Y. Wu; R. Z. Wang; S. Shiochi

    2007-01-01

    As a high-efficiency air-conditioning scheme, the variable refrigerant flow (VRF) air-conditioning system is finding its way in office buildings. However, there is no well-known energy simulation software available so far which can be used for the energy analysis of VRF. Based on the generic dynamic building energy simulation environment, EnergyPlus, a new VRF module is developed and the energy usage

  6. Exploiting a nonlinear restoring force to improve the performance of flow energy harvesters

    NASA Astrophysics Data System (ADS)

    Bibo, Amin; Alhadidi, Ali H.; Daqaq, Mohammed F.

    2015-01-01

    This paper investigates employing a nonlinear restoring force to improve the performance of flow energy harvesters (FEHs). To that end, a galloping FEH possessing a quartic potential energy function of the form V =1/2 ?y2+1/4 ?y4 is considered. This potential function is used to model either a softening (? > 0, ? < 0), hardening (? > 0, ? > 0), or bi-stable (? < 0, ? > 0) restoring force. A physics-based model of the harvester is obtained assuming piezoelectric transduction and a quasi-steady flow field. The model is validated against experimental data and used to obtain a closed-form solution of the response by employing a multiple scaling perturbation analysis using the Jacobi elliptic functions. The attained solution is subsequently used to investigate the influence of the nonlinearity on the performance of the harvester and to illustrate how to optimize the restoring force in order to maximize the output power for given design conditions and airflow parameters. Specifically, it is shown that for similar design parameters and equal magnitudes of ?, and ?, a bi-stable energy harvester outperforms all other configurations as long as the inter-well motions are activated. On the other hand, if the motion of the bi-stable harvester is limited to a single well, then a harvester incorporating a softening nonlinear restoring force outperforms all other configurations. Furthermore, when comparing two FEHs incorporating the same type of restoring force at the optimal load and similar values of ?, then the FEH with the smaller ? is shown to provide higher output power levels.

  7. Energy-Saving Design for Pressure Difference Control in Variable Flow Air Conditioning Systems 

    E-print Network

    Chen, Y.; Zhang, Z.

    2006-01-01

    Zhang Senior Engineer Postgraduate Wuhan Architectural Design Institute, Wuhan, China, 430014 Chenyh918@263.net Abstract: This paper analyzes energy-saving design for pressure-difference control in a variable flow air...

  8. Energy-Saving Design for Pressure Difference Control in Variable Flow Air Conditioning Systems

    E-print Network

    Chen, Y.; Zhang, Z.

    2006-01-01

    This paper analyzes energy-saving design for pressure-difference control in a variable flow air conditioning system, including the application of a pressure-difference control valve and the installation position of a pressure-difference transducer...

  9. Title: Scalable Low-Head Axial-Type Venturi-Flow Energy Principal Investigator: Nadipuram Prasad

    E-print Network

    Johnson, Eric E.

    for an axial-flow hydropower generating system will show the technical feasibility to harvest or scavenge: Nadipuram Prasad Sponsor: U.S. Department of Energy Summary: In-depth studies of the turbine dynamics

  10. Global energy conversion rate from geostrophic flows into internal lee waves in the deep ocean

    E-print Network

    Nikurashin, Maxim

    A global estimate of the energy conversion rate from geostrophic flows into internal lee waves in the ocean is presented. The estimate is based on a linear theory applied to bottom topography at O(1–10) km scales obtained ...

  11. Modeling Hot Gas Flow in the Low-Luminosity Active Galactic Nucleus of NGC3115

    NASA Astrophysics Data System (ADS)

    Shcherbakov, Roman V.; Wong, K.; Irwin, J.; Reynolds, C. S.

    2014-01-01

    Based on the dynamical estimates of the black hole (BH) mass, NGC3115 hosts the closest billion solar mass BH. Deep studies of the center revealed a very underluminous active galactic nucleus (AGN) immersed in an old massive nuclear star cluster. Recent 1Ms Chandra X-ray visionary project observations of the NGC3115 nucleus resolved hot tenuous gas, which fuels the AGN. In this work we connect the processes in the nuclear star cluster with the feeding of the supermassive BH. We model the hot gas flow sustained by the injection of matter and energy by the stars and supernova explosions. We incorporate electron heat conduction, the gravitational pull of the stellar mass, cooling, and Coulomb collisions. We reach reduced ?i^2=1 fitting simulated X-ray emission to the spatially and spectrally resolved observed X-ray data. Radial modeling favors a low BH mass <1.3*10^{9}Msun. The best-fitting supernova rate and the best-fitting mass injection rate are consistent with their expected values. The stagnation point is at r_ s 1arcsec, so that most of gas, including the gas at a Bondi radius r_B=2-4arcsec, outflows from the region. We put an upper limit on the accretion rate at 2*10^{-3}Msun/yr. We find a shallow density profile r^{-?} with ? 1 over a large dynamic range. This density profile is determined in the feeding region 0.5-10arcsec as an interplay of four processes and effects: (1) the radius-dependent mass injection, (2) the effect of the galactic gravitational potential, (3) the accretion flow onset at r<1arcsec, and (4) the outflow at r>1arcsec. Conduction makes the density profile shallow only very close to the BH at r<0.1arcsec. The gas temperature is close to the virial temperature T_v at any radius. The temperature profile is shallow outside of the Bondi radius because the enclosed stellar mass is proportional to radius M_en r, which leads to flat virial temperature profile.

  12. Active and reactive power in stochastic resonance for energy harvesting

    E-print Network

    Kubota, Madoka; Hikihara, Takashi

    2015-01-01

    A power allocation to active and reactive power in stochastic resonance is discussed for energy harvesting from mechanical noise. It is confirmed that active power can be increased at stochastic resonance, in the same way of the relationship between energy and phase at an appropriate setting in resonance.

  13. REDUCED CEREBRAL BLOOD FLOW WITH ORTHOSTASIS PRECEDES HYPOCAPNIC HYPERPNEA, SYMPATHETIC ACTIVATION AND POTS

    PubMed Central

    Del Pozzi, Andrew T.; Schwartz, Christopher E.; Tewari, Deepali; Medow, Marvin S.; Stewart, Julian M.

    2014-01-01

    Hyperventilation, and reduced cerebral blood flow velocity can occur in postural tachycardia syndrome (POTS). We studied orthostatically intolerant patients, with suspected POTS, with a chief complaint of upright dyspnea. Based on our observations of an immediate reduction of cerebral blood flow velocity with orthostasis, we hypothesize that the resulting ischemic hypoxia of the carotid body causes chemoreflex activation, hypocapnic hyperpnea, sympathetic activation, and increased heart rate and blood pressure in this subset of POTS. We compared 11 dyspneic POTS subjects to 10 healthy controls during a 70° head-up tilt. In POTS subjects during initial orthostasis prior to BP recovery; central blood volume and mean arterial pressure were reduced (P<0.025) resulting in a significant (P<0.001) decrease in cerebral blood flow velocity, which temporally preceded (17±6 s; P<0.025) a progressive increase in minute ventilation and decrease in end tidal CO2 (P<0.05), compared to controls. Sympathoexcitation, measured by muscle sympathetic nerve activity, was increased in POTS, (P<0.01), and inversely proportional to end tidal CO2 and resulted in an increase in heart rate, (P<0.001), total peripheral resistance (P<0.025), and a decrease in cardiac output (P<0.025). The decrease in cerebral blood flow velocity and mean arterial pressure during initial orthostasis was greater (P<0.025) in POTS. Our data suggest that exaggerated initial central hypovolemia during initial orthostatic hypotension in POTS results in reduced cerebral blood flow velocity and postural hypocapnic hyperpnea that perpetuates cerebral ischemia. We hypothesize that sustained hypocapnia and cerebral ischemia produce sympathoexcitation, tachycardia and a statistically significant increase in blood pressure. PMID:24711524

  14. Active Control of Panel Vibrations Induced by a Boundary Layer Flow

    NASA Technical Reports Server (NTRS)

    Chow, Pao-Liu

    1998-01-01

    In recent years, active and passive control of sound and vibration in aeroelastic structures have received a great deal of attention due to many potential applications to aerospace and other industries. There exists a great deal of research work done in this area. Recent advances in the control of sound and vibration can be found in the several conference proceedings. In this report we will summarize our research findings supported by the NASA grant NAG-1-1175. The problems of active and passive control of sound and vibration has been investigated by many researchers for a number of years. However, few of the articles are concerned with the sound and vibration with flow-structure interaction. Experimental and numerical studies on the coupling between panel vibration and acoustic radiation due to flow excitation have been done by Maestrello and his associates at NASA/Langley Research Center. Since the coupled system of nonlinear partial differential equations is formidable, an analytical solution to the full problem seems impossible. For this reason, we have to simplify the problem to that of the nonlinear panel vibration induced by a uniform flow or a boundary-layer flow with a given wall pressure distribution. Based on this simplified model, we have been able to study the control and stabilization of the nonlinear panel vibration, which have not been treated satisfactorily by other authors. The vibration suppression will clearly reduce the sound radiation power from the panel. The major research findings will be presented in the next three sections. In Section II we shall describe our results on the boundary control of nonlinear panel vibration, with or without flow excitation. Section III is concerned with active control of the vibration and sound radiation from a nonlinear elastic panel. A detailed description of our work on the parametric vibrational control of nonlinear elastic panel will be presented in Section IV. This paper will be submitted to the Journal of Acoustic Society of America for publication.

  15. Directional shear flow and Rho activation prevent the endothelial cell apoptosis induced by micropatterned anisotropic geometry

    PubMed Central

    Wu, Chia-Ching; Li, Yi-Shuan; Haga, Jason H.; Kaunas, Roland; Chiu, Jeng-Jiann; Su, Fong-Chin; Usami, Shunichi; Chien, Shu

    2007-01-01

    To study the roles of anisotropic cell morphology and directionality of mechanical force in apoptosis, the spreading of human umbilical vein endothelial cells (HUVECs) was constrained by growing on micropatterned (MP) strips of fibronectin (FN, 20 ?g/cm2) with widths of 15, 30, and 60 ?m on silicone membrane. Cells on 30- and 60-?m strips, like cells on a nonpatterned (NP) surface coated with FN, showed clear actin stress fibers with anchoring spots of phosphorylated focal adhesion kinase (p-FAK) and no significant apoptosis. On 15-?m strips, cells had few stress fibers, no p-FAK, and significant apoptosis. After seeding for 12 h, the cells were subjected to pulsatile shear stress (12 ± 4 dyn/cm2) parallel or perpendicular to MP strips, or kept under static condition. Parallel flow caused cell elongation with enhanced stress fibers and p-FAK, and a reduction in apoptosis, but perpendicular flow did not. The Rho inhibitory C3 exoenzyme abolished the effects of parallel flow. RhoV14, the constitutively active Rho, enhanced stress fibers and p-FAK, and prevented apoptosis of HUVECs on 15-?m strips under static condition. RhoV14 also reduced cell apoptosis under both parallel and perpendicular flows. Our results indicate that cell apoptosis can be modulated by changes in ECM micropatterning, anisotropic cell morphology, and mechanical forces. These extracellular microenvironment factors affect cell survival through alterations in Rho GTPase activity, stress fiber organization, and FAK phosphorylation. PMID:17229844

  16. Analysis of up-flow aerated biological activated carbon filter technology in drinking water treatment.

    PubMed

    Lu, Shaoming; Liu, Jincui; Li, Shaowen; Biney, Elizabeth

    2013-01-01

    Problems have been found in the traditional post-positioned down-flow biological activated carbon filter (DBACF), such as microorganism leakage and low biodegradability. A pilot test was carried out to place a BACF between the sediment tank and the sand filter; a new technology of dual media up-flow aerated biological activated carbon filter (UBACF) was developed. Results showed that in terms of the new process, the up-flow mode was better than the down-flow. Compared with the DBACF, the problem of microorganism leakage could be well resolved with the UBACF process by adding disinfectant before the sand filtration, and a similar adsorption effect could be obtained. For the tested raw water, the COD(Mn) and NH3-N removal rate was 54.6% and 85.0%, respectively, similar to the waterworks with the DBACF process. The UBACF greatly enhanced oxygen supply capability and mass transfer rate via aeration, and the NH3-N removal ability was significantly improved from 1.5 mg/L to more than 3 mg/L. Influent to the UBACF with higher turbidity could be coped with through the primary filtration of the ceramisite layer combined with fluid-bed technology, which gave the carbon bed a low-turbidity environment of less than 1.0 NTU. The backwashing parameters and carbon abrasion rate of the two processes were almost the same. PMID:24350490

  17. Energy flow and power phenomena in electrical circuits: illusions and reality

    Microsoft Academic Search

    L. S. Czarnecki

    2000-01-01

    Contents  ?Common opinions respective to the nature of the reactive power, energy flow and oscillations, as well as the notion of the\\u000a apparent power in single- and in three-phase systems are discussed in this paper. It is shown that some interpretations of\\u000a powers and energy flow in linear, single-phase circuits are often generalized for more complex situations where these interpretations\\u000a are

  18. Theoretical analysis of the current and energy flow to the anode in the diffuse vacuum arc

    Microsoft Academic Search

    C. Wieckert; W. Egli

    1989-01-01

    The current energy flow to the anode in a diffuse vacuum arc is investigated using a simple multicathode-spot fluid description of the interelectrodic plasma. Decisive for the current constriction and the energy flow to the anode center is the space-charge sheath in front of the anode. This sheath not only determines the current-density distribution at the anode, but also may

  19. Symmetry energy and isospin dependence of cross- section: sensitivity to transverse flow

    E-print Network

    Sakshi Gautam

    2011-12-13

    We study the relative contribution of the symmetry energy and isospin dependence of the nucleon-nucleon cross section to the collective transverse in-plane flow for the reactions of Ca+Ca having N/Z varying from 1.0, 1.6 and 2.0. We see that role of symmetry energy to the flow increases with N/Z of the system.

  20. Flow limitation and regulation of functional residual capacity during exercise in a physically active aging population.

    PubMed

    Johnson, B D; Reddan, W G; Pegelow, D F; Seow, K C; Dempsey, J A

    1991-05-01

    In 29 older (69 +/- 1 yr), physically active subjects (VO2max = 44 +/- 2 ml.kg-1.min-1), we determined the effect of an age-related decline in elastic lung recoil (i.e., Vmax50 = 65% of 30-yr-old adults) on the ventilatory response to progressive exercise. More specifically, we assessed if expiratory airflow limits were achieved and how this may modulate the regulation of end-expiratory lung volume (EELV). We found that with only mild to moderate (50 to 75% VO2max) exercise, the mean EELV was reduced 0.38 +/- 0.07 L, and that expiratory flow limitation was present over 25 +/- 4% of the VT. In 11 subjects during this intensity of exercise, EELV was within their closing capacity. As exercise intensity progressed, VT plateaued at 58 +/- 2% of the vital capacity, and increased expiratory air flow rates were achieved by significantly increasing the EELV back to near resting levels, thereby moving a portion of the expiratory tidal flow-volume envelope away from the constraints of the effort independent portion of the maximal flow-volume curve. During heavy exercise, end-inspiratory lung volume (EILV) approached 90% of TLC. To achieve greater expiratory flow with maximal exercise, EELV remained similar to the previous intensity, and a significantly greater portion of the tidal expiratory flow-volume envelope (greater than 40% of the VT) became flow-limited. Despite this significant expiratory limitation, a rise in EELV, and an EILV approaching TLC, TI/Ttot remained constant throughout exercise, and the ventilatory response for the metabolic demand (VA/VCO2) was appropriate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2024851

  1. Flow measurement by pulsed-neutron activation techniques at the PKL facility at Erlangen (Germany). [PWR

    SciTech Connect

    Kehler, P.

    1982-03-01

    Flow velocities in the downcomer at the PKL facility (in Erlangen, Germany) were measured by the Pulsed-Neutron Activation (PNA) techniques. This was the first time that a fully automated PNA system, incorporating a dedicated computer for on-line data reduction, was used for flow measurements. A prototype of a portable, pulsed, high-output neutron source, developed by the Sandia National Laboratories for the US Nuclear Regulatory Commission, was also successfully demonstrated during this test. The PNA system was the primary flow-measuring device used at the PKL, covering the whole range of velocities of interest. In this test series, the PKL simulated small-break accidents similar to the one that occurred at TMI. The flow velocities in the downcomer were, therefore, very low, ranging between 0.03 and 0.35 m/sec. Two additional flow-measuring methods were used over a smaller range of velocities. Wherever comparison was possible, the PNA-derived velocity values agreed well with the measurements performed by the two more conventional methods.

  2. The study of surface-active element oxygen on flow patterns and penetration in A-TIG welding

    NASA Astrophysics Data System (ADS)

    Zhao, Yuzhen; Shi, Yaowu; Lei, Yongping

    2006-06-01

    A three-dimensional mathematical model was developed to simulate the flow patterns and temperature distributions in a moving A-TIG weld pool of 304 stainless steels with different oxygen content using PHOENICS software. It is shown that the surface-active element, oxygen, is important, because it affects the weld shape by changing the flow patterns in the weld pool. The weld bead penetration and the depth/width ratio increase first sharply and then remain nearly a constant with increasing oxygen content. Depending upon the oxygen contents, three, one, or two vortexes that have different positions, strength, and directions may be found in the weld pool. Oxygen can cause significant changes in the weld shape by varying the sign of the surface tension coefficient. The situation with the maximum surface tension moves from the edge to the center with increasing oxygen content. As oxygen content exceeds a critical value, a positive surface tension coefficient dominates the flow patterns. The vortexes with opposite directions caused by positive surface tension coefficient can efficiently transfer the thermal energy from the arc, creating a deep weld pool. The critical oxygen content increases with the increase of the welding current.

  3. System Size, Energy, Pseudorapidity, and Centrality Dependence of Elliptic Flow

    E-print Network

    B. Alver; for the PHOBOS Collaboration

    2006-10-24

    This paper presents measurements of the elliptic flow of charged particles as a function of pseudorapidity and centrality from Cu-Cu collisions at 62.4 and 200 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider (RHIC). The elliptic flow in Cu-Cu collisions is found to be significant even for the most central events. For comparison with the Au-Au results, it is found that the detailed way in which the collision geometry (eccentricity) is estimated is of critical importance when scaling out system-size effects. A new form of eccentricity, called the participant eccentricity, is introduced which yields a scaled elliptic flow in the Cu-Cu system that has the same relative magnitude and qualitative features as that in the Au-Au system.

  4. Transport of a dilute active suspension in pressure-driven channel flow

    E-print Network

    Ezhilan, Barath

    2015-01-01

    Confined suspensions of active particles show peculiar dynamics characterized by wall accumulation, as well as upstream swimming, centerline depletion and shear-trapping when a pressure-driven flow is imposed. We use theory and numerical simulations to investigate the effects of confinement and non-uniform shear on the dynamics of a dilute suspension of Brownian active swimmers by incorporating a detailed treatment of boundary conditions within a simple kinetic model where the configuration of the suspension is described using a conservation equation for the probability distribution function of particle positions and orientations, and where particle-particle and particle-wall hydrodynamic interactions are neglected. Based on this model, we first investigate the effects of confinement in the absence of flow, in which case the dynamics is governed by a swimming Peclet number, or ratio of the persistence length of particle trajectories over the channel width, and a second swimmer-specific parameter whose inverse...

  5. Continuous monitoring of a large active earth flow using an integrated GPS - automatic total station approach

    Microsoft Academic Search

    A. Corsini

    2009-01-01

    Landslide monitoring has evolved as a crucial tool in civil protection to mitigate and prevent disasters. The research presents an approach to continuous monitoring of a large-scale active earth flow using a system that integrates surface measurements obtained by a GPS and an automatic total station. With the data obtained from the system the landslide can be monitored in near-real-time

  6. Sustained hyperglycaemia increases muscle blood flow but does not affect sympathetic activity in resting humans

    Microsoft Academic Search

    P. J. M. van Gurp; G. A. Rongen; J. W. M. Lenders; A. K. M. Al Nabawy; H. J. L. M. Timmers; C. J. J. Tack

    2005-01-01

    An increase in capillary blood flow and pressure in response to diabetes mellitus may lead to microangiopathy. We hypothesize that these haemodynamic changes are caused by a decreased activity of the sympathetic nervous system due to episodes of sustained hyperglycaemia. Twelve healthy volunteers consecutively underwent a hyperglycaemic experiment (HYPER), with the plasma glucose level maintained at 20 mmol.l-1 for 6 h by

  7. Gradient vector flow based active shape model for lung field segmentation in chest radiographs.

    PubMed

    Xu, Tao; Mandal, Mrinal; Long, Richard; Basu, Anup

    2009-01-01

    Accurate lung field segmentation is crucial to computer-aided diagnosis (CAD) of lung diseases such as lung cancer and tuberculosis (TB). In this paper, we propose a modified gradient vector flow based active shape model (GVF-ASM) for lung field extraction from chest radiographs. Experimental results show that the proposed technique provides around 3-5% improvement over the ASM techniques. PMID:19964999

  8. Persistent energy flow for a stochastic wave equation model in nonequilibrium statistical mechanics

    E-print Network

    Thomas, Lawrence E

    2012-01-01

    We consider a one-dimensional partial differential equation system modeling heat flow around a ring. The system includes a Klein-Gordon wave equation for a field satisfying spatial periodic boundary conditions, as well as Ornstein-Uhlenbeck stochastic differential equations with finite rank dissipation and stochastic driving terms modeling heat baths. There is an energy flow around the ring. In the case of a linear field with different (fixed) bath temperatures, the energy flow can persist even when the interaction with the baths is turned off. A simple example is given.

  9. Persistent energy flow for a stochastic wave equation model in nonequilibrium statistical mechanics

    NASA Astrophysics Data System (ADS)

    Thomas, Lawrence E.

    2012-09-01

    We consider a one-dimensional partial differential equation system modeling heat flow around a ring. The system includes a Klein-Gordon wave equation for a field satisfying spatial periodic boundary conditions, as well as Ornstein-Uhlenbeck stochastic differential equations with finite rank dissipation and stochastic driving terms modeling heat baths. There is an energy flow around the ring. In the case of a linear field with different (fixed) bath temperatures, the energy flow can persist even when the interaction with the baths is turned off. A simple example is given.

  10. Application Study of the Pump Water Flow Station for Building Energy Consumption Monitoring and Control Optimization

    E-print Network

    Liu, G.; Liu, M.

    2006-01-01

    ICEBO2006, Shenzhen, China HVAC Technologies for Energy Efficiency, Vol. V-1-1 Application Study of the Pump Water Flow Station for Building Energy Consumption Monitoring and Control Optimization Guopeng Liu Mingsheng Liu, Ph.D., P... conditions. The curve is sometimes called the head-capacity curve (H-Q) for the pump. The pump water-flow station (PWS) was developed by Liu et al. (2006) recently. The PWS can measure the water flow through the pumps using the pump speed, pump head...

  11. Flows at the Edge of an Active Region: Observation and Interpretation

    E-print Network

    Boutry, Céline; Vial, Jean-Claude; Régnier, Stéphane

    2012-01-01

    Upflows observed at the edges of active regions have been proposed as the source of the slow solar wind. In the particular case of Active Region (AR) 10942, where such an upflow has been already observed, we want to evaluate the part of this upflow that actually remains confined in the magnetic loops that connect AR10942 to AR10943. Both active regions were visible simultaneously on the solar disk and were observed by STEREO/SECCHI EUVI. Using Hinode/EIS spectra, we determine the Doppler shifts and densities in AR10943 and AR10942, in order to evaluate the mass flows. We also perform magnetic field extrapolations to assess the connectivity between AR10942 and AR10943. AR10943 displays a persistent downflow in Fe XII. Magnetic extrapolations including both ARs show that this downflow can be connected to the upflow in AR10942. We estimate that the mass flow received by AR10943 areas connected to AR10942 represents about 18% of the mass flow from AR10942. We conclude that the upflows observed on the edge of acti...

  12. Active Control of Jets in Cross-Flow for Film Cooling Applications

    NASA Technical Reports Server (NTRS)

    Nikitopoulos, Dimitris E.

    2003-01-01

    Jets in cross-flow have applications in film cooling of gas turbine vanes, blades and combustor liners. Their cooling effectiveness depends on the extent to which the cool jet-fluid adheres to the cooled component surface. Lift-off of the cooling jet flow or other mechanisms promoting mixing, cause loss of cooling effectiveness as they allow the hot "free-stream" fluid to come in contact with the component surface. The premise of this project is that cooling effectiveness can be improved by actively controlling (e.9. forcing, pulsing) the jet flow. Active control can be applied to prevent/delay lift-off and suppress mixing. Furthermore, an actively controlled film-cooling system coupled with appropriate sensory input (e.g. temperature or heat flux) can adapt to spatial and temporal variations of the hot-gas path. Thus, it is conceivable that the efficiency of film-cooling systems can be improved, resulting in coolant fluid economy. It is envisioned that Micro Electro-Mechanical Systems (MEMS) will play a role in the realization of such systems. As a first step, a feasibility study will be conducted to evaluate the concept, identify actuation and sensory elements and develop a control strategy. Part of this study will be the design of a proof-of-concept experiment and collection of necessary data.

  13. Energy Dependence of Fast-Neutron Activation Cross Sections

    Microsoft Academic Search

    A. E. Johnsrud; M. G. Silbert; H. H. Barschall

    1959-01-01

    Fast-neutron capture cross sections of 24 nuclides ranging from A=51 to A=197 have been measured by an activation method, in the neutron energy region from 0.15 to 6.2 Mev. The neutron energy spreads were of the order of 0.1 Mev so that cross sections averaged over many energy levels of the compound nucleus were measured. Activities induced in samples by

  14. Solar Energy Education. Home economics: student activities. Field test edition

    SciTech Connect

    Not Available

    1981-03-01

    A view of solar energy from the standpoint of home economics is taken in this book of activities. Students are provided information on solar energy resources while performing these classroom activities. Instructions for the construction of a solar food dryer and a solar cooker are provided. Topics for study include window treatments, clothing, the history of solar energy, vitamins from the sun, and how to choose the correct solar home. (BCS)

  15. Flow control for a high energy laser turret using trapped vortices

    NASA Astrophysics Data System (ADS)

    Burd, J. E.

    1981-12-01

    The Department of Defense is concerned with the viability of an airborne high energy laser system. The laser is housed in a blunt turret atop a NKC-135 aircraft. Turbulence generated by flow separation around the turret causes optical distortion of the laser beam. Control of flow separation is needed to improve laser beam performance especially for aft-aimed turrets. One technique proposed for flow control is a fairing design which will stabilize shed vortices by suction. A two dimensional computer model was used to design a fairing compatible with present test equipment. Experimental research of this fairing design was conducted in wind tunnel tests. Although flow mapping demonstrated improved flow performance through the use of suction, total quiescent flow was never achieved. A more adequate three dimensional model is needed to design a fairing that will stabilize trapped vortices.

  16. Drag Reduction by Polymers in Turbulent Channel Flows: Energy Redistribution Between Invariant Empirical Modes

    E-print Network

    Elisabetta De Angelis; Carlo M. Casciola; Victor S. L'vov; Renzo Piva; Itamar Procaccia

    2002-10-29

    We address the phenomenon of drag reduction by dilute polymeric additive to turbulent flows, using Direct Numerical Simulations (DNS) of the FENE-P model of viscoelastic flows. It had been amply demonstrated that these model equations reproduce the phenomenon, but the results of DNS were not analyzed so far with the goal of interpreting the phenomenon. In order to construct a useful framework for the understanding of drag reduction we initiate in this paper an investigation of the most important modes that are sustained in the viscoelastic and Newtonian turbulent flows respectively. The modes are obtained empirically using the Karhunen-Loeve decomposition, allowing us to compare the most energetic modes in the viscoelastic and Newtonian flows. The main finding of the present study is that the spatial profile of the most energetic modes is hardly changed between the two flows. What changes is the energy associated with these modes, and their relative ordering in the decreasing order from the most energetic to the least. Modes that are highly excited in one flow can be strongly suppressed in the other, and vice versa. This dramatic energy redistribution is an important clue to the mechanism of drag reduction as is proposed in this paper. In particular there is an enhancement of the energy containing modes in the viscoelastic flow compared to the Newtonian one; drag reduction is seen in the energy containing modes rather than the dissipative modes as proposed in some previous theories.

  17. Flow depth and energy coefficient relatiohnships for stepped spillways

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A multi-year, large-scale physical model study of stepped chutes was conducted over a broad range of design parameters (i.e. step heights, slopes, and unit discharges). Air entrainment developed naturally as the flow descended the chute. Air entrainment began to develop downstream of the surface i...

  18. Multicomponent flow compressor: A new concept for efficient energy conversion

    NASA Astrophysics Data System (ADS)

    Minardi, J. E.; Vonohain, H. P.; Lawson, M. O.; Newman, R. K.; Wattendorf, F. L.

    1986-12-01

    The research is based on an innovative concept of tailoring a multicomponent flow by controlled injection of uniform-size, several-micron-diameter particles in a gas flow, such as air or helium for admission to a compressor rotor, to obtain greatly improved compressor performance characteristics: three such major improvements are lowest work of compression (essentially isothermal), low rotor tip speeds, and very high compressor pressure ratios in a single stage. The objectives of the first phase were to demonstrate the effects of tailoring the multicomponent flow on the compressor pressure rise and to provide the conceptual design of the major elements of the multicomponent flow compressor system. A high specific speed rotor with 40 blades was designed and built. The rotor was housed in a vaneless diffuser and scroll designed to diffuse the particle laden gas. Preliminary data obtained with the compressor rig shows a 40% increase in pressure using particles when compared to the air only values. However, theory indicates that substantial gains in performance are still possible. Modifications to the compressor rig are presented and will be used to obtain additional data at higher particle loadings.

  19. 78 FR 64414 - Assistance to Foreign Atomic Energy Activities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-29

    ...NNSA), Department of Energy (DOE). ACTION: Notice...Assistance to Foreign Atomic Energy Activities since 1986...consistent with current global civil nuclear trade practices...subject to the Secretary of Energy's specific authorization...time for the public to review and comment on the...

  20. ENERGY DEPENDENCE OF FAST-NEUTRON ACTIVATION CROSS SECTIONS

    Microsoft Academic Search

    A. E. Johnsrud; M. G. Silbert; H. H. Barschall

    1959-01-01

    Fast-neutron capture cross sections of 24 nuclides ranging from A = 51 ; to A = 197 were measured by an activation method, in the neutron energy region ; from 0.15 to 6.2 Mev. The neutron energy spreads were of the order of 0.1 Mev so ; that cross sections averaged over many energy levels of the compound nucleus were

  1. Energy consumption and economic activities in Iran

    Microsoft Academic Search

    Mehrzad Zamani

    2007-01-01

    The causal relationship between overall GDP, industrial and agricultural value added and consumption of different kinds of energy are investigated using vector error correction model for the case of Iran within 1967–2003. A long-run unidirectional relationship from GDP to total energy and bidirectional relationship between GDP and gas as well as GDP and petroleum products consumption for the whole economy

  2. Energy flow in high speed perforation and cutting

    SciTech Connect

    van Thiel, M.

    1980-10-07

    It is demonstrated that effects of long rod penetrators on targets can be modeled by introducing a high pressure (energy) column on the penetration path in place of the projectile. This energy can be obtained from the kinetic energy of the penetrator; the equations of state of the materials used and a Bernoulli penetration condition. The model is supported by detailed hydro calculations.

  3. Determination of transient stability constrained line flow limits: an application of linearized techniques for the transient energy function method

    Microsoft Academic Search

    V. Vittal; Jolene LeAnne Gleason

    1989-01-01

    An effort is made to determine how line flow changes affect the robustness of the power system using the energy margin sensitivities to power generation shifts and power flow distribution factors. A method to obtain stability constrained line flow limits is proposed. The major difference between this research work and other research in transient energy function sensitivity techniques for line

  4. Bayesian modeling of perceived surface slant from actively-generated and passively-observed optic flow.

    PubMed

    Caudek, Corrado; Fantoni, Carlo; Domini, Fulvio

    2011-01-01

    We measured perceived depth from the optic flow (a) when showing a stationary physical or virtual object to observers who moved their head at a normal or slower speed, and (b) when simulating the same optic flow on a computer and presenting it to stationary observers. Our results show that perceived surface slant is systematically distorted, for both the active and the passive viewing of physical or virtual surfaces. These distortions are modulated by head translation speed, with perceived slant increasing directly with the local velocity gradient of the optic flow. This empirical result allows us to determine the relative merits of two alternative approaches aimed at explaining perceived surface slant in active vision: an "inverse optics" model that takes head motion information into account, and a probabilistic model that ignores extra-retinal signals. We compare these two approaches within the framework of the bayesian theory. The "inverse optics" bayesian model produces veridical slant estimates if the optic flow and the head translation velocity are measured with no error; because of the influence of a "prior" for flatness, the slant estimates become systematically biased as the measurement errors increase. The bayesian model, which ignores the observer's motion, always produces distorted estimates of surface slant. Interestingly, the predictions of this second model, not those of the first one, are consistent with our empirical findings. The present results suggest that (a) in active vision perceived surface slant may be the product of probabilistic processes which do not guarantee the correct solution, and (b) extra-retinal signals may be mainly used for a better measurement of retinal information. PMID:21533197

  5. Bayesian Modeling of Perceived Surface Slant from Actively-Generated and Passively-Observed Optic Flow

    PubMed Central

    Caudek, Corrado; Fantoni, Carlo; Domini, Fulvio

    2011-01-01

    We measured perceived depth from the optic flow (a) when showing a stationary physical or virtual object to observers who moved their head at a normal or slower speed, and (b) when simulating the same optic flow on a computer and presenting it to stationary observers. Our results show that perceived surface slant is systematically distorted, for both the active and the passive viewing of physical or virtual surfaces. These distortions are modulated by head translation speed, with perceived slant increasing directly with the local velocity gradient of the optic flow. This empirical result allows us to determine the relative merits of two alternative approaches aimed at explaining perceived surface slant in active vision: an “inverse optics” model that takes head motion information into account, and a probabilistic model that ignores extra-retinal signals. We compare these two approaches within the framework of the Bayesian theory. The “inverse optics” Bayesian model produces veridical slant estimates if the optic flow and the head translation velocity are measured with no error; because of the influence of a “prior” for flatness, the slant estimates become systematically biased as the measurement errors increase. The Bayesian model, which ignores the observer's motion, always produces distorted estimates of surface slant. Interestingly, the predictions of this second model, not those of the first one, are consistent with our empirical findings. The present results suggest that (a) in active vision perceived surface slant may be the product of probabilistic processes which do not guarantee the correct solution, and (b) extra-retinal signals may be mainly used for a better measurement of retinal information. PMID:21533197

  6. THE MAGNETIC ENERGY-HELICITY DIAGRAM OF SOLAR ACTIVE REGIONS

    SciTech Connect

    Tziotziou, Kostas; Georgoulis, Manolis K. [Research Center for Astronomy and Applied Mathematics (RCAAM), Academy of Athens, 4 Soranou Efesiou Street, Athens, GR-11527 (Greece); Raouafi, Nour-Eddine [Johns Hopkins University Applied Physics Laboratory (JHU/APL), 11100 Johns Hopkins Rd. Laurel, MD 20723-6099 (United States)

    2012-11-01

    Using a recently proposed nonlinear force-free method designed for single-vector magnetograms of solar active regions, we calculate the instantaneous free magnetic energy and relative magnetic helicity budgets in 162 vector magnetograms corresponding to 42 different active regions. We find a statistically robust, monotonic correlation between the free magnetic energy and the relative magnetic helicity in the studied regions. This correlation implies that magnetic helicity, in addition to free magnetic energy, may be an essential ingredient for major solar eruptions. Eruptive active regions appear well segregated from non-eruptive ones in both free energy and relative helicity with major (at least M-class) flares occurring in active regions with free energy and relative helicity exceeding 4 Multiplication-Sign 10{sup 31} erg and 2 Multiplication-Sign 10{sup 42} Mx{sup 2}, respectively. The helicity threshold agrees well with estimates of the helicity contents of typical coronal mass ejections.

  7. Emplacement and inflation of pahoehoe sheet flows: observations and measurements of active lava flows on Kilauea volcano, Hawaii

    USGS Publications Warehouse

    Hon, K.; Kauahikaua, J.; Denlinger, R.; Mackay, K.

    1994-01-01

    Inflated pahoehoe sheet flows have a distinctive horizontal upper surface, which can be several hundred meters across, and are bounded to steep monoclinal uplifts. The inflated sheet flows studied ranged from 1 to 5 m in thickness, but initially propagated as thin sheets of fluid pahoehoe lava, generally 20-30 cm thick. The morphology of the lava as flow advanced is described. Inflated sheet flows from Kilauea and Mauna Loa are morphologically similar to some thick Icelandic and submarine sheet flows, suggesting a similar mechanism of emplacement. -from Authors

  8. Kinetic analysis of the energy transport of bursty bulk flows in the plasma sheet

    NASA Astrophysics Data System (ADS)

    Cao, Jinbin; Ma, Yuduan; Parks, George; Reme, Henri; Dandouras, Iannis; Zhang, Tielong

    2013-01-01

    The energy transport of bursty bulk flows (BBFs) is very important to the understanding of substorm energy transport. Previous studies all use the MHD bulk parameters to calculate the energy flux density of BBFs. In this paper, we use the kinetic approach, i.e., ion velocity distribution function, to study the energy transport of an earthward bursty bulk flow observed by Cluster C1 on 30 July 2002. The earthward energy flux density calculated using kinetic approach QKx is obviously larger than that calculated using MHD bulk parameters QMHDx. The mean ratio QKx/QMHDx in the flow velocity range 200-800 km/s is 2.7, implying that the previous energy transport of BBF estimated using MHD approach is much underestimated. The underestimation results from the deviation of ion velocity distribution from ideal Maxwellian distribution. The energy transport of BBF is mainly provided by ions above 10 keV although their number density Nf is much smaller than the total ion number density N. The ratio QKx/QMHDx is basically proportional to the ratio N/Nf. The flow velocity v(E) increases with increasing energy. The ratio Nf/N is perfectly proportional to flow velocity Vx. A double ion component model is proposed to explain the above results. The increase of energy transport capability of BBF is important to understanding substorm energy transport. It is inferred that for a typical substorm, the ratio of the energy transport of BBF to the substorm energy consumption may increase from the previously estimated 5% to 34% or more.

  9. Flow Activation of AMP-Activated Protein Kinase in Vascular Endothelium Leads to Krüppel-Like Factor 2 Expression

    PubMed Central

    Young, Angela; Wu, Wei; Sun, Wei; Larman, Harry B.; Wang, Nanping; Li, Yi-Shuan; Shyy, John Y.; Chien, Shu; García-Cardeña, Guillermo

    2009-01-01

    Objective Vascular endothelial cells (ECs) confer atheroprotection at locations of the arterial tree where pulsatile laminar flow (PS) exists with a high shear stress and a large net forward direction. We investigated whether the PS-induced expression of the transcription factor Krüppel-Like Factor 2 (KLF2) in cultured ECs and its expression in the mouse aorta is regulated by AMP-activated protein kinase (AMPK). Methods and Results AMPK inhibition by Compound C or siRNA had a significant blocking effect on the PS-induced KLF2 expression. The induction of KLF2 by PS led to the increase in eNOS and the suppression of ET-1, which could be reversed by KLF2 siRNA. In addition, PS induced the phosphorylation of ERK5 and MEF2 which are necessary for the KLF2 expression. These mechanotransduction events were abrogated by the blockade of AMPK. Furthermore, the phosphorylation levels of ERK5 and MEF2, as well as the expression of KLF2, were significantly reduced in the aorta of AMPK?2 knockout mice when compared with wild-type control mice. Conclusion The flow-mediated AMPK activation is a newly defined KLF2 regulatory pathway in vascular endothelium that acts via ERK5/MEF2. PMID:19696400

  10. Conical Euler analysis and active roll suppression for unsteady vortical flows about rolling delta wings

    NASA Technical Reports Server (NTRS)

    Lee-Rausch, Elizabeth M.; Batina, John T.

    1993-01-01

    A conical Euler code was developed to study unsteady vortex-dominated flows about rolling, highly swept delta wings undergoing either forced motions or free-to-roll motions that include active roll suppression. The flow solver of the code involves a multistage, Runge-Kutta time-stepping scheme that uses a cell-centered, finite-volume, spatial discretization of the Euler equations on an unstructured grid of triangles. The code allows for the additional analysis of the free to-roll case by simultaneously integrating in time the rigid-body equation of motion with the governing flow equations. Results are presented for a delta wing with a 75 deg swept, sharp leading edge at a free-stream Mach number of 1.2 and at 10 deg, 20 deg, and 30 deg angle of attack alpha. At the lower angles of attack (10 and 20 deg), forced-harmonic analyses indicate that the rolling-moment coefficients provide a positive damping, which is verified by free-to-roll calculations. In contrast, at the higher angle of attack (30 deg), a forced-harmonic analysis indicates that the rolling-moment coefficient provides negative damping at the small roll amplitudes. A free-to-roll calculation for this case produces an initially divergent response, but as the amplitude of motion grows with time, the response transitions to a wing-rock type of limit cycle oscillation, which is characteristic of highly swept delta wings. This limit cycle oscillation may be actively suppressed through the use of a rate-feedback control law and antisymmetrically deflected leading-edge flaps. Descriptions of the conical Euler flow solver and the free-to roll analysis are included in this report. Results are presented that demonstrate how the systematic analysis of the forced response of the delta wing can be used to predict the stable, neutrally stable, and unstable free response of the delta wing. These results also give insight into the flow physics associated with unsteady vortical flows about delta wings undergoing forced motions and free-to-roll motions, including the active suppression of the wing-rock type phenomenon. The conical Euler methodology developed is directly extend able to three-dimensional calculations.

  11. Natural cytotoxic activity of gilthead seabream (Sparus aurata L.) leucocytes. Assessment by flow cytometry and microscopy.

    PubMed

    Cuesta, A; Esteban, M A; Meseguer, J

    1999-11-30

    This paper describes an easy and sensitive flow cytometric assay for assessing the non-specific cytotoxic activity of gilthead seabream (Sparus aurata L.) head-kidney leucocytes against tumor target cells. Concomitantly, the cytotoxic process and the cell types involved were microscopically studied. The assay was based on the consecutive use of two fluorochromes. The targets were preincubated with 3,3'-dioctadecyloxacarbocyanine perchlorate (DiO) and then mixed with effectors. At the end of incubation time propidium iodide (PI) was added. While live effectors were non-fluorescent, live and dead targets retained the DiO (green) fluorescence and non-viable targets and effectors showed PI (red) fluorescence staining. The kinetics of the cytotoxic activity was studied from 10 to 240 min. Lymphocytes, monocyte-macrophages and granulocytes showed non-specific cytotoxic activity, as demonstrated by light and electron microscopy. In conclusion, the technique presented validates the effectiveness of a dual-color flow cytometric assay for assessing the activity of non-specific cytotoxic cells in fish. PMID:10587298

  12. Energy utilization rates during shuttle extravehicular activities

    Microsoft Academic Search

    J. M. Waligora; K. V. Kumar

    1995-01-01

    The work rates or energy utilization rates during EVA are major factors in sizing of life support systems. These rates also provide a measure of ease of EVA and its cost in crew fatigue. From the first Shuttle EVA on the STS-6 mission in 1983, we have conducted 59 man-EVA and 341 man-hours of EVA. Energy utilization rates have been

  13. Active Flow Separation Control of a Stator Vane Using Surface Injection in a Multistage Compressor Experiment

    NASA Technical Reports Server (NTRS)

    Culley, Dennis E.; Bright, Michelle M.; Prahst, Patricia S.; Strazisar, Anthony J.

    2003-01-01

    Micro-flow control actuation embedded in a stator vane was used to successfully control separation and improve near stall performance in a multistage compressor rig at NASA Glenn. Using specially designed stator vanes configured with internal actuation to deliver pulsating air through slots along the suction surface, a research study was performed to identify performance benefits using this microflow control approach. Pressure profiles and unsteady pressure measurements along the blade surface and at the shroud provided a dynamic look at the compressor during microflow air injection. These pressure measurements lead to a tracking algorithm to identify the onset of separation. The testing included steady air injection at various slot locations along the vane. The research also examined the benefit of pulsed injection and actively controlled air injection along the stator vane. Two types of actuation schemes were studied, including an embedded actuator for on-blade control. Successful application of an online detection and flow control scheme will be discussed. Testing showed dramatic performance benefit for flow reattachment and subsequent improvement in diffusion through the use of pulsed controlled injection. The paper will discuss the experimental setup, the blade configurations, and preliminary CFD results which guided the slot location along the blade. The paper will also show the pressure profiles and unsteady pressure measurements used to track flow control enhancement, and will conclude with the tracking algorithm for adjusting the control.

  14. Energy Harvesting from Fluid Flow in Water Pipelines for Smart Metering Applications

    NASA Astrophysics Data System (ADS)

    Hoffmann, D.; Willmann, A.; Göpfert, R.; Becker, P.; Folkmer, B.; Manoli, Y.

    2013-12-01

    In this paper a rotational, radial-flux energy harvester incorporating a three-phase generation principle is presented for converting energy from water flow in domestic water pipelines. The energy harvester together with a power management circuit and energy storage is used to power a smart metering system installed underground making it independent from external power supplies or depleting batteries. The design of the radial-flux energy harvester is adapted to the housing of a conventional mechanical water flow meter enabling the use of standard components such as housing and impeller. The energy harvester is able to generate up to 720 mW when using a flow rate of 20 l/min (fully opened water tab). A minimum flow rate of 3 l/min is required to get the harvester started. In this case a power output of 2 mW is achievable. By further design optimization of the mechanical structure including the impeller and magnetic circuit the threshold flow rate can be further reduced.

  15. What Happens to Physical Activity Behavior, Motivation, Self-Concept, and Flow After Completing School? A Longitudinal Study

    Microsoft Academic Search

    Andrew J. Martin; Gregory Arief D. Liem; Leandra Coffey; Carissa Martinez; Philip P. Parker; Herbert W. Marsh; Susan A. Jackson

    2010-01-01

    With particular focus on the year following completion of high school, the present study sought to establish the status of young people's physical activity behavior, physical activity motivation, physical activity flow, and physical self-concept. Among a sample of 213 Australian participants assessed in their final year of school and then one year later, findings suggested a significant increase in physical

  16. Actual activation energy of electrode process under mixed kinetics conditions

    Microsoft Academic Search

    F. I. Danilov; V. S. Protsenko

    2009-01-01

    In the case of a single-electron reaction with account for slow diffusion of reagents, equations for actual (experimentally\\u000a determined) activation energies of two types were derived and analyzed: real energy A f, i.e., the energy measured at a constant electrode polarization value ? = const) and formal energy (?f, i.e., the value measured at a constant value of potential vs.

  17. The effect of amphetamine on regional cerebral blood flow during cognitive activation in schizophrenia

    SciTech Connect

    Daniel, D.G.; Weinberger, D.R.; Jones, D.W.; Zigun, J.R.; Coppola, R.; Handel, S.; Bigelow, L.B.; Goldberg, T.E.; Berman, K.F.; Kleinman, J.E. (Clinical Brain Disorders Branch, Saint Elizabeths, National Institute of of Mental Health, WA (USA))

    1991-07-01

    To explore the role of monoamines on cerebral function during specific prefrontal cognitive activation, we conducted a double-blind placebo-controlled crossover study of the effects of 0.25 mg/kg oral dextroamphetamine on regional cerebral blood flow (rCBF) as determined by 133Xe dynamic single-photon emission-computed tomography (SPECT) during performance of the Wisconsin Card Sorting Test (WCST) and a sensorimotor control task. Ten patients with chronic schizophrenia who had been stabilized for at least 6 weeks on 0.4 mg/kg haloperidol participated. Amphetamine produced a modest, nonsignificant, task-independent, global reduction in rCBF. However, the effect of amphetamine on task-dependent activation of rCBF (i.e., WCST minus control task) was striking. Whereas on placebo no significant activation of rCBF was seen during the WCST compared with the control task, on amphetamine significant activation of the left dorsolateral prefrontal cortex (DLPFC) occurred (p = 0.0006). Both the mean number of correct responses and the mean conceptual level increased (p less than 0.05) with amphetamine relative to placebo. In addition, with amphetamine, but not with placebo, a significant correlation (p = -0.71; p less than 0.05) emerged between activation of DLPFC rCBF and performance of the WCST task. These findings are consistent with animal models in which mesocortical catecholaminergic activity modulates and enhances the signal-to-noise ratio of evoked cortical activity.

  18. Novel gradient vector flow-based balloon force for active contours

    NASA Astrophysics Data System (ADS)

    Zhu, Guopu; Zhang, Shuqun; Chen, Xijun; Wang, Changhong

    2009-04-01

    Active contours, as a technique for boundary extraction, have been successfully used in image processing and computer vision. One of the knotty problems of active contours is to conform to the object boundary with complex shape, which could bring heavy manual work at the initialization procedure. The gradient vector flow (GVF) field has been one of the most popular external forces that can increase the capture range of active contours and bidirectionally evolve the active contours toward the object boundary. However, it has a poor performance when dealing with some complex shapes, such as semi-closed concave, screwy concave, hooked concave, as well as the others presented in our experiments. We propose a novel GVF-based balloon force, which can efficiently assist the GVF field in driving active contours toward the complex object shapes. This additional force is used only when the active contours are prevented from evolving toward the object boundary by the saddle and/or stationary points in the GVF field. Therefore, it can maintain the bidirectional evolution property of the GVF and meanwhile take advantage of the power of the balloon force in segmenting complex shapes. Various experimental results on image segmentation are presented to show the good performance of the proposed active contour model that uses the GVF field and the proposed balloon force together.

  19. Development of high-lift laminar wing using steady active flow control

    NASA Astrophysics Data System (ADS)

    Clayton, Patrick J.

    Fuel costs represent a large fraction of aircraft operating costs. Increased aircraft fuel efficiency is thus desirable. Laminar airfoils have the advantage of reduced cruise drag and increased fuel efficiency. Unfortunately, they cannot perform adequately during high-lift situations (i.e. takeoff and landing) due to low stall angles and low maximum lift caused by flow separation. Active flow control has shown the ability to prevent or mitigate separation effects, and increase maximum lift. This fact makes AFC technology a fitting solution for improving high-lift systems and reducing the need for slats and flap elements. This study focused on experimentally investigating the effects of steady active flow control from three slots, located at 1%, 10%, and 80% chord, respectively, over a laminar airfoil with 45 degree deflected flap. A 30-inch-span airfoil model was designed, fabricated, and then tested in the Bill James 2.5'x3' Wind Tunnel at Iowa State University. Pressure data were collected along the mid-span of the airfoil, and lift and drag were calculated. Five test cases with varying injection locations and varying C? were chosen: baseline, blown flap, leading edge blowing, equal blowing, and unequal blowing. Of these cases, unequal blowing achieved the greatest lift enhancement over the baseline. All cases were able to increase lift; however, gains were less than anticipated.

  20. Blood flow to long bones indicates activity metabolism in mammals, reptiles and dinosaurs

    PubMed Central

    Seymour, Roger S.; Smith, Sarah L.; White, Craig R.; Henderson, Donald M.; Schwarz-Wings, Daniela

    2012-01-01

    The cross-sectional area of a nutrient foramen of a long bone is related to blood flow requirements of the internal bone cells that are essential for dynamic bone remodelling. Foramen area increases with body size in parallel among living mammals and non-varanid reptiles, but is significantly larger in mammals. An index of blood flow rate through the foramina is about 10 times higher in mammals than in reptiles, and even higher if differences in blood pressure are considered. The scaling of foramen size correlates well with maximum whole-body metabolic rate during exercise in mammals and reptiles, but less well with resting metabolic rate. This relates to the role of blood flow associated with bone remodelling during and following activity. Mammals and varanid lizards have much higher aerobic metabolic rates and exercise-induced bone remodelling than non-varanid reptiles. Foramen areas of 10 species of dinosaur from five taxonomic groups are generally larger than from mammals, indicating a routinely highly active and aerobic lifestyle. The simple measurement holds possibilities offers the possibility of assessing other groups of extinct and living vertebrates in relation to body size, behaviour and habitat. PMID:21733896

  1. Relationships Among the Energy, Emergy, and Money Flows of the United States From 1900 to 2011

    EPA Science Inventory

    In this paper, we examine the relationships among the energy, emergy, and money flows of the United States from 1900 to 2011. To establish a theoretical basis for understanding these relationships, Energy Systems Language models of the resource base for the World System and of e...

  2. Leaf litter processing and energy flow through macroinvertebrates in a woodland pond (Switzerland)

    Microsoft Academic Search

    B. Oertli

    1993-01-01

    Energy generated by leaf litter processing and its flow through the associated macroinvertebrate community was quantified in a pond near Geneva (Switzerland). Annual density, biomass, and production on oak (Quercus robur) leaf litter were assessed for all macroinvertebrate taxa with emphasis on predators. Empirical energetic relations provided an energy budget for the macroinvertebrate community. On 1 m2 of pond bottom,

  3. The Energy Function of a General Multimachine System With a Unified Power Flow Controller

    Microsoft Academic Search

    Valentin Azbe; Uros Gabrijel; Dusan Povh; Rafael Mihalic

    2005-01-01

    In order to be able to successfully apply direct methods or other energy-function-based calculations in power systems, which include flexible AC transmission systems (FACTS) devices, the influence of those devices should be properly considered. This is currently not always possible in power systems incorporating unified power flow controllers (UPFCs) because the present energy functions for electric power systems do not

  4. Magnetic and Thermal Energy Flow During Disruptions in DIII--D

    Microsoft Academic Search

    A. W. Hyatt; R. L. Lee; D. A. Humphreys; A. G. Kellman; P. L. Taylor; J. W. Cuthbertson

    1996-01-01

    A plasma disruption results in the rapid loss of stored thermal and magnetic energy. We measure the spatial distribution and temporal evolution of energy flows during disruptions in DIII--D using magnetics, bolometry and toroidally separated infrared video (IRTV) cameras. Bolometer tomography and IRTV data are used to separate divertor heat flux into radiation and conduction components. A Poynting flux analysis

  5. Research on the energy-saving potentiality of electro-hydraulic Power Steering System based on energy flow

    Microsoft Academic Search

    Zhu Renxue; Gao Lanfang; Li Xuezhi

    2010-01-01

    The development and design of new energy-saving system of electro-hydraulic power steering (EHPS) has extensive application prospect. EHPS system is analyzed by using energy flow method, system model based on energy cost is established, and relevant compute simulation is performed. Tests are carried out on the hardware-in-the-loop (HIL) bench. The results showed that system voltage supply, PWM duty cycle, pump

  6. Grain size reduction in granular flows of spheres - The effects of critical impact energy

    NASA Technical Reports Server (NTRS)

    Richman, M. W.; Oyediran, A. A.

    1992-01-01

    Methods employed to derive recent kinetic theories for rapid noncomminuting granular flows are extended to homogeneous flows in which a fraction of the repeated collisions produce tiny fractures on the particles' peripheries and gradually reduce their effective diameters. The theory consists of balance equations for mass, momentum, and energy, as well as constitutive relations for the presence tensor and collisional rates of mass and energy lost. The work of Richman and Chou (1989) is improved by incorporating into the constitutive theory the critical impact energy below which no mass loss occurs in a binary collision. The theory is applied to granular shear flows and, for fixed shear rates, predicts the time variations of the solid fraction granular temperature, and induced stresses, as well as their extreme sensitivities to small changes in the critical impact energy.

  7. A cortico-hippocampal learning rule shapes inhibitory microcircuit activity to enhance hippocampal information flow

    PubMed Central

    Basu, Jayeeta; Srinivas, Kalyan V.; Cheung, Stephanie K.; Taniguchi, Hiroki; Huang, Z. Josh

    2013-01-01

    Summary How does coordinated activity between distinct brain regions implement a set of learning rules to sculpt information processing in a given neural circuit? Using interneuron cell-type specific optical activation and pharmacogenetic silencing in vitro, we show that temporally precise pairing of direct entorhinal perforant path (PP) and trisynaptic Schaffer collateral (SC) inputs to CA1 pyramidal cells selectively suppresses SC-associated perisomatic inhibition from cholecystokinin (CCK) expressing interneurons. The CCK interneurons provide a surprisingly strong feed-forward inhibitory drive to effectively control the coincident excitation of CA1 pyramidal neurons by convergent inputs. Thus, in-phase cortico-hippocampal activity provides a powerful heterosynaptic learning rule for long-term gating of information flow through the hippocampal excitatory macrocircuit by the silencing of the CCK inhibitory microcircuit. PMID:24050406

  8. On the possibility of negative activation energies in bimolecular reactions

    NASA Technical Reports Server (NTRS)

    Jaffe, R. L.

    1978-01-01

    The temperature dependence of the rate constants for model reacting systems was studied to understand some recent experimental measurements which imply the existence of negative activation energies. A collision theory model and classical trajectory calculations are used to demonstrate that the reaction probability can vary inversely with collision energy for bimolecular reactions occurring on attractive potential energy surfaces. However, this is not a sufficient condition to ensure that the rate constant has a negative temperature dependence. On the basis of these calculations, it seems unlikely that a true bimolecular reaction between neutral molecules will have a negative activation energy.

  9. Generalization and extension of the law of acoustic energy conservation in a nonuniform flow

    NASA Technical Reports Server (NTRS)

    Myers, M. K.

    1986-01-01

    An exact conservation equation is derived which generalizes the familiar acoustic energy equations. The new relation is valid for arbitrary disturbances to a viscous, compressible flow. It is suggested by a development of the acoustic energy equation by means of a regular perturbation expansion of the general energy equation of fluid mechanics. A perturbation energy density and flux are defined and identified as the exact physical quantities whose leading order perturbation representations are the usual acoustic energy density and flux. The conservation equation governing the perturbation energy quantities is shown to yield previously known results for several special cases.

  10. Material and energy flows in the materials production, assembly, and end-of-life stages of the automotive lithium-ion battery life cycle

    Microsoft Academic Search

    J. B. Dunn; L. Gaines; M. Barnes; M. Wang; J. Sullivan

    2012-01-01

    This document contains material and energy flows for lithium-ion batteries with an active cathode material of lithium manganese oxide (LiMnâOâ). These data are incorporated into Argonne National Laboratory's Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model, replacing previous data for lithium-ion batteries that are based on a nickel\\/cobalt\\/manganese (Ni\\/Co\\/Mn) cathode chemistry. To identify and determine the mass

  11. Influence of internal energy on the stability of relativistic flows

    E-print Network

    Manuel Perucho; Michal Hanasz; Jose Maria Marti; Helene Sol

    2002-12-05

    A set of simulations concerning the influence of internal energy on the stability of relativistic jets is presented. Results show that perturbations saturate when the amplitude of the velocity perturbation approaches the speed of light limit. Also, contrary to what predicted by linear stability theory, jets with higher specific internal energy appear to be more stable.

  12. Energy flow for integrated apple production in Greece

    Microsoft Academic Search

    Argiro V. Strapatsa; George D. Nanos; Constantinos A. Tsatsarelis

    2006-01-01

    Integrated production requires constant improvement of methods employed to achieve high fruit quality and yield with minimal inputs. This work was undertaken to evaluate the energy inputs for apple production, to identify the highest energy consuming operations and propose ways to improve them. Integrated production methods were employed during 1999 and 2000 at 26 apple (Malus domestica Borkh.) orchards in

  13. Observations of the effect of wind on the cooling of active lava flows

    USGS Publications Warehouse

    Keszthelyi, L.; Harris, A.J.L.; Dehn, J.

    2003-01-01

    We present the first direct observations of the cooling of active lava flows by the wind. We confirm that atmospheric convective cooling processes (i.e., the wind) dominate heat loss over the lifetime of a typical pahochoe lava flow. In fact, the heat extracted by convection is greater than predicted, especially at wind speeds less than 5 m/s and surface temperatures less than 400??C. We currently estimate that the atmospheric heat transfer coefficient is about 45-50 W m-2 K-1 for a 10 m/s wind and a surface temperature ???500??C. Further field experiments and theoretical studies should expand these results to a broader range of surface temperatures and wind speeds.

  14. Example of active circulation control of the unsteady separated flow past a semi-infinite plate

    NASA Astrophysics Data System (ADS)

    Cortelezzi, L.; Leonard, A.; Doyle, J. C.

    1994-02-01

    Active circulation control of the two-dimensional unsteady separated flow past a semi-infinite plate with transverse motion is considered. The rolling-up of the separated shear layer is modelled by a point vortex whose time-dependent circulation is predicted by an unsteady Kutta condition. A suitable vortex shedding mechanism is introduced. A control strategy able to maintain constant circulation when a vortex is present is derived. An exact solution for the nonlinear controller is then obtained. Dynamical systems analysis is used to explore the performance of the controlled system. The control strategy is applied to a class of flows and the results are discussed. A procedure to determine the position and the circulation of the vortex, knowing the velocity signature on the plate, is derived. Finally, a physical explanation of the control mechanism is presented.

  15. Preferential flow in connected soil structures and the principle of "maximum energy dissipation": A thermodynamic perspective

    NASA Astrophysics Data System (ADS)

    Zehe, E.; Blume, T.; Bloeschl, G.

    2009-04-01

    "There is preferential flow at all scales"? This was a key message in a talk on ?Idle thoughts on a unifying theory of catchment hydrology? given by Bloeschl (2006). In this context ?preferential flow? was used to address rapid water flow along spatially connected flow paths of minimum flow resistance. Preferential flow seems in fact rather the rule than the exception. It occurs locally in non capillary macropores, at the hillslope scale in surface rills or through subsurface pipes. Rapid flow in connected biopores or sometimes shrinkage cracks is today accepted to play a key role for transport of agrochemicals in cohesive soils. The spatial distribution of worm burrows in the landscape may, furthermore, exert crucial control on rainfall runoff response and sediment yields at the hillslope and catchment scales. However, even if the population of connected biopores/macropores is known in soil we struggle in predicting onset, timing and strength of preferential flow events. Preferential flow is an intermittent, threshold phenomenon. Onset and intensity seems to be determined by the strength of the rainfall forcing and the wetness state of the soil. Furthermore, burrows of deep digging aenecic earthworms can ? even when being abandoned ? persist over decades as suggested by accumulation of clay particles or even radio nuclides. Thus, these structures ?survive? severe rainfall and subsurface flow events and still remain functional in the hydrological system. Why is it sometimes ?favourable? to take flow paths of minimum flow resistance and sometimes not? Why do these flow paths/ structures persist such a long time? Following Kleidon and Schimansky (2008) we suggest that a thermodynamic perspective ? looking at soil water flow as dissipative process in an open, non equilibrium thermodynamic system ? may help unrevealing these questions. However, we suggest a complementary perspective on soil water flow focusing rather on entropy production but on dissipation of Helmholtz free energy. Thermodynamic equilibrium is a state of minimum free energy. The latter is determined by potential energy and capillary energy in soil, which in turn strongly depends on soil moisture, pore size distribution and depth to groundwater. The objective of this study is threefold. First, we will introduce the necessary theoretical background. Second we suggest ? based on simulations with a physically based hydrological model ? that water flow in connected preferential pathways assures a faster relaxation towards thermodynamic equilibrium through a faster drainage of ?excess water? and a faster redistribution of ?capillary water? within the soil. The latter process is of prime importance in case of cohesive soils where the pore size distribution is dominated by medium and small pores. Third, an application of a physically based hydrological model to predict water flow and runoff response from a pristine catchment in the Chilenean Andes underpins this hypothesis. Behavioral model structures that allow a good match of the observed hydrographs turned out to be most efficient in dissipating free energy by means of preferential flow. It seems that a population of connected preferential pathways is favourable both for resilience and stability of these soils during extreme events and to retain water resources for the ecosystem at the same time. We suggest that this principle of ?maximum energy dissipation? may on the long term help us to better understand why soil structures remain stable, threshold nature of preferential as well as offer a means to further reduce model structural uncertainty. Bloeschl, G. 2006. Idle thoughts on a unifying theory of catchment Hydrology. Geophysical Research Abstracts, Vol. 8, 10677, 2006 SRef-ID: 1607-7962/gra/EGU06-A-10677 European Geosciences Union 2006 Kleidon, A., and S. Schymanski (2008), Thermodynamics and optimality of the water budget on land: A review, Geophys. Res. Lett., 35, L20404, doi:10.1029/ 2008GL035393.

  16. Vortex shedding induced energy harvesting from piezoelectric materials in heating, ventilation and air conditioning flows

    NASA Astrophysics Data System (ADS)

    Weinstein, L. A.; Cacan, M. R.; So, P. M.; Wright, P. K.

    2012-04-01

    A cantilevered piezoelectric beam is excited in a heating, ventilation and air conditioning (HVAC) flow. This excitation is amplified by the interactions between (a) an aerodynamic fin attached at the end of the piezoelectric cantilever and (b) the vortex shedding downstream from a bluff body placed in the air flow ahead of the fin/cantilever assembly. The positioning of small weights along the fin enables tuning of the energy harvester to operate at resonance for flow velocities from 2 to 5 m s-1, which are characteristic of HVAC ducts. In a 15 cm diameter air duct, power generation of 200 ?W for a flow speed of 2.5 m s-1 and power generation of 3 mW for a flow speed of 5 m s-1 was achieved. These power outputs are sufficient to power a wireless sensor node for HVAC monitoring systems or other sensors for smart building technology.

  17. Transient radiative energy transfer in incompressible laminar flows

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Singh, D. J.

    1987-01-01

    Analysis and numerical procedures are presented to investigate the transient radiative interactions of nongray absorbing-emitting species in laminar fully-developed flows between two parallel plates. The particular species considered are OH, CO, CO2, and H2O and different mixtures of these. Transient and steady-state results are obtained for the temperaure distribution and bulk temperature for different plate spacings, wall temperatures, and pressures. Results, in general, indicate that the rate of radiative heating can be quite high during earlier times. This information is useful in designing thermal protection systems for transient operations.

  18. Energy monitoring system based on human activity in the workplace

    NASA Astrophysics Data System (ADS)

    Mustafa, Nur Hanim; Husain, Mohd Nor; Aziz, Mohamad Zoinol Abidin Abdul; Othman, Mohd Azlishah; Malek, Fareq

    2015-05-01

    Human behaviors always related to day routine activities in a smart house directly give the significant factor to manage energy usage in human life. An Addition that, the factor will contribute to the best efficiency of the system. This paper will focus on the monitoring efficiency based on duration time in office hours around 8am until 5pm which depend on human behavior at working place. Besides that, the correlation coefficient method is used to show the relation between energy consumption and energy saving based on the total hours of time energy spent. In future, the percentages of energy monitoring system usage will be increase to manage energy saving based on human behaviors. This scenario will help to see the human activity in the workplace in order to get the energy saving and support world green environment.

  19. Energy-momentum tensor from the Yang-Mills gradient flow

    E-print Network

    Hiroshi Suzuki

    2015-06-17

    The product of gauge fields generated by the Yang-Mills gradient flow for positive flow times does not exhibit the coincidence-point singularity and a local product is thus independent of the regularization. Such a local product can furthermore be expanded by renormalized local operators at zero flow time with finite coefficients that are governed by renormalization group equations. Using these facts, we derive a formula that relates the small flow-time behavior of certain gauge-invariant local products and the correctly-normalized conserved energy-momentum tensor in the Yang-Mills theory. Our formula provides a possible method to compute the correlation functions of a well-defined energy-momentum tensor by using lattice regularization and Monte Carlo simulation.

  20. Energy utilization rates during shuttle extravehicular activities.

    PubMed

    Waligora, J M; Kumar, K V

    1995-01-01

    The work rates or energy utilization rates during EVA are major factors in sizing of life support systems. These rates also provide a measure of ease of EVA and its cost in crew fatigue. From the first Shuttle EVA on the STS-6 mission in 1983, we have conducted 59 man-EVA and 341 man-hours of EVA. Energy utilization rates have been measured on each of these EVA. Metabolic rate was measured during each EVA using oxygen utilization corrected for suit leakage. From 1981-1987, these data were available for average data over the EVA or over large segments of the EVA. Since 1987, EVA oxygen utilization data were available at 2-minute intervals. The average metabolic rate on Shuttle EVA (194 kcal/hr.) has been significantly lower than metabolic rates during Apollo and Skylab missions. Peak rates have been below design levels, infrequent, and of short duration. The data suggest that the energy cost of tasks may be inversely related to the degree of training for the task. The data provide insight on the safety margins provided by life support designs and on the energy cost of Station construction EVA. PMID:11540993

  1. Energy utilization rates during shuttle extravehicular activities

    NASA Astrophysics Data System (ADS)

    Waligora, J. M.; Kumar, K. V.

    The work rates or energy utilization rates during EVA are major factors in sizing of life support systems. These rates also provide a measure of ease of EVA and its cost in crew fatigue. From the first Shuttle EVA on the STS-6 mission in 1983, we have conducted 59 man-EVA and 341 man-hours of EVA. Energy utilization rates have been measured on each of these EVA. Metabolic rate was measured during each EVA using oxygen utilization corrected for suit leakage. From 1981-1987, these data were available for average data over the EVA or over large segments of the EVA. Since 1987, EVA oxygen utilization data were available at 2-minute intervals. The average metabolic rate on Shuttle EVA (194 kcal/hr.) has been significantly lower than metabolic rates during Apollo and Skylab missions. Peak rates have been below design levels, infrequent, and of short duration. The data suggest that the energy cost of tasks may be inversely related to the degree of training for the task. The data provide insight on the safety margins provided by life support designs and on the energy cost of Station construction EVA.

  2. A review of UK wind energy activities

    Microsoft Academic Search

    P. J. Musgrove

    1982-01-01

    Wind power activities in Great Britain are reviewed, including a brief summary of historical windmill usage and details of developmental efforts in large and small wind turbines. An annual average resource of 5 m\\/sec at 10 m has been extrapolated to predict an 8-10 m\\/sec resource at the hub heights of large wind turbines. Initial estimates indicate that at least

  3. Fluctuation analysis of activity biosensor images for the study of information flow in signaling pathways

    PubMed Central

    Vilela, Marco; Halidi, Nadia; Besson, Sebastien; Elliott, Hunter; Hahn, Klaus; Tytell, Jessica

    2014-01-01

    Comprehensive understanding of cellular signal transduction requires accurate measurement of the information flow in molecular pathways. In the past, information flow has been inferred primarily from genetic or protein-protein interactions. Although useful for overall signaling, these approaches are limited in that they typically average over populations of cells. Single cell data of signaling states are emerging, but these data are usually snapshots of a particular time point or limited to averaging over a whole cell. However, many signaling pathways are activated only transiently in specific subcellular regions. Protein activity biosensors allow measurement of the spatiotemporal activation of signaling molecules in living cells. These data contain highly complex, dynamic information that can be parsed out in time and space and compared with other signaling events as well as changes in cell structure and morphology. We describe in this chapter the use of computational tools to correct, extract, and process information from timelapse images of biosensors. These computational tools allow one to explore the biosensor signals in a multiplexed approach in order to reconstruct the sequence of signaling events and consequently the topology of the underlying pathway. The extraction of this information, dynamics and topology, provides insight into how the inputs of a signaling network are translated into its biochemical or mechanical outputs. PMID:23280114

  4. Incident-energy and system-size dependence of directed flow

    E-print Network

    Gang Wang

    2007-02-14

    We present STAR's measurements of directed flow for charged hadrons in Au+Au and Cu+Cu collisions at $\\sqrt{s_\\mathrm{NN}} = 200$ GeV and 62.4 GeV, as a function of pseudorapidity, transverse momentum and centrality. We find that directed flow depends on the incident energy, but not on the system size. We extend the validity of limiting fragmentation hypothesis to different collision systems.

  5. An Experimental Comparison of Min-Cut\\/Max-Flow Algorithms for Energy Minimization in Vision

    Microsoft Academic Search

    Yuri Boykov; Vladimir Kolmogorov

    2004-01-01

    Abstract After [15, 31, 19, 8, 25, 5] minimum cut\\/maximum flow algorithms on graphs emerged as an increasingly useful tool for exact or approximate,energy minimization,in low-level vision. The combinatorial,optimization,literature provides many,min-cut\\/max-flow algorithms with different polynomial time complexity. Their practical efficiency, however, has to date been studied mainly,outside the scope of computer,vision. The goal of this paper is to provide an

  6. An Experimental Comparison of Min-cut\\/Max-flow Algorithms for Energy Minimization in Vision

    Microsoft Academic Search

    Yuri Boykov; Vladimir Kolmogorov

    2001-01-01

    After (15, 31, 19, 8, 25, 5) minimum cut\\/maximum flow algorithms on graphs emerged as an increasingly useful tool for exact or approximate energy minimization in low-level vision. The combinatorial optimization literature provides many min-cut\\/max-flow algorithms with different polynomial time complexity. Their practical efficiency, however, has to date been studied mainly outside the scope of computer vision. The goal of

  7. A Unified Three-Phase Power-Flow Analysis Model For Electronically Coupled Distributed Energy Resources

    Microsoft Academic Search

    Mohamed Zakaria Kamh; Reza Iravani

    2011-01-01

    This paper develops and presents a unified and generic three-phase, steady-state, fundamental-frequency, se- quence-frame-based model of the voltage-sourced converter (VSC) for power-flow analysis of VSC-interfaced Distributed Energy Resource (DER) units. The model is unified since it represents: 1) three-wire and four-wire VSC configurations; 2) balanced and unbalanced power-flow scenarios; 3) various VSC control strategies and options; and 4) operating limits

  8. System size, energy and pseudorapidity dependence of directed and elliptic flow at RHIC

    E-print Network

    S. Manly

    2005-10-10

    PHOBOS measurements of elliptic flow are presented as a function of pseudorapidity, centrality, transverse momentum, energy and nuclear species. The elliptic flow in Cu-Cu is surprisingly large, particularly for the most central events. After scaling out the geometry through the use of an alternative form of eccentricity, called the participant eccentricity, which accounts for nucleon position fluctuations in the colliding nuclei, the relative magnitude of the elliptic flow in the Cu-Cu system is qualitatively similar to that measured in the Au-Au system.

  9. Sympathetic activation increases basilar arterial blood flow in normotensive but not hypertensive rats.

    PubMed

    Chang, Hsi-Hsien; Lee, Yuan-Chieh; Chen, Mei-Fang; Kuo, Jon-Son; Lee, Tony J F

    2012-03-01

    The close apposition between sympathetic and parasympathetic nerve terminals in the adventitia of cerebral arteries provides morphological evidence that sympathetic nerve activation causes parasympathetic nitrergic vasodilation via a sympathetic-parasympathetic interaction mechanism. The decreased parasympathetic nerve terminals in basilar arteries (BA) of spontaneously hypertensive rat (SHR) and renovascular hypertensive rats (RHR) compared with Wistar-Kyoto rats (WKY), therefore, would diminish this axo-axonal interaction-mediated neurogenic vasodilation in hypertension. Increased basilar arterial blood flow (BABF) via axo-axonal interaction during sympathetic activation was, therefore, examined in anesthetized rats by laser-Doppler flowmetry. Electrical stimulation (ES) of sympathetic nerves originating in superior cervical ganglion (SCG) and topical nicotine (10-30 ?M) onto BA of WKY significantly increased BABF. Both increases were inhibited by tetrodotoxin, 7-nitroindazole (neuronal nitric oxide synthase inhibitor), and ICI-118,551 (?(2)-adrenoceptor antagonist), but not by atenolol (?(1)-adrenoceptor antagonist). Topical norepinephrine onto BA also increased BABF, which was abolished by atenolol combined with 7-nitroindazole or ICI-118,551. Similar results were found in prehypertensive SHR. However, in adult SHR and RHR, ES of sympathetic nerves or topical nicotine caused minimum or no increase of BABF. It is concluded that excitation of sympathetic nerves to BA in WKY causes parasympathetic nitrergic vasodilation with increased BABF. This finding indicates an endowed functional neurogenic mechanism for increasing the BABF or brain stem blood flow in coping with increased local sympathetic activities in acutely stressful situations such as the "fight-or-flight response." This increased blood flow in defensive mechanism diminishes in genetic and nongenetic hypertensive rats due most likely to decreased parasympathetic nitrergic nerve terminals. PMID:22210747

  10. Performance of a piezoelectric energy harvester driven by air flow

    NASA Astrophysics Data System (ADS)

    Kitio Kwuimy, C. A.; Litak, G.; Borowiec, M.; Nataraj, C.

    2012-01-01

    A turbulent wind source for possible energy harvesting is considered. To increase the amplitude of vibration, we apply a magnetopiezoelastic oscillator having a double well Duffing potential. The output voltage response of the system for different level of wind excitations is analyzed. The energy harvesting appeared to be the most efficient for the conditions close to the stochastic resonance region where the potential barrier was overcame.

  11. Equipartition of Energy and Local Isotropy in Turbulent Flows

    Microsoft Academic Search

    Mahinder S. Uberoi

    1957-01-01

    Homogeneous turbulence in which ?v2? = ?w2? ? ?u2? was produced experimentally, where ?u2?, ?v2?, and ?w2? are the mean-square turbulent velocities in x, y, and z direction, respectively. The decay of turbulence and the energy transfer between ?u2? and (?v2?+?w2?) were measured, and it was found that the larger components (?v2? and ?w2?) are losing more energy due to

  12. Distribution of activation energies in high temperature superconductors

    NASA Astrophysics Data System (ADS)

    Griessen, R.; Hagen, C. W.; Lensink, J.; de Groot, D. G.

    1989-12-01

    The inversion scheme of Hagen and Griessen is used to determine the distribution m(E ?) of activation energies E ? for thermally activated flux motion from experimental data on magnetization relaxation in a Bi 2CaSr 2Cu 2O 8 single crystal and YBa 2Cu 3O 7 thin films.

  13. A compact low energy multibeam gamma-ray densitometer for pipe-flow measurements

    NASA Astrophysics Data System (ADS)

    Tjugum, Stein-Arild; Frieling, Joop; Johansen, Geir Anton

    2002-12-01

    A compact low-energy multibeam gamma-ray densitometer for oil/water/gas pipe-flow measurement has been built at the University of Bergen (UoB). The instrument consists of one Am-241 source and three detectors, all collimated and embedded in the pipe wall. Only the 59.5 keV radiation energy of the source is utilized. Two of the detectors measure transmitted radiation across the pipe flow, and one measure scattered radiation at a 90° angle. The purpose of the multibeam measurement geometry is to acquire flow regime information and to reduce the flow regime dependency of the gas volume fraction (GVF) measurements. The measurement of scattered radiation enables the dual modality densitometry (DMD) measurement principle to be exploited. Its basic principle is to combine the measurement of scattered and transmitted radiation in order to obtain salinity independent GVF measurements. The salinity dependency is otherwise strongly significant when using low-energy radiation. It is also possible to measure the salinity by using this principle. The instrument is a laboratory prototype, and it has been used for characterising the measurement principle and to test different detector alternatives. The testing of the instrument includes static tests on plastic phantoms, tests on simulated water/gas flow and three phase flow loop tests. Both the multibeam measurement principle and the DMD principle have been verified to provide valuable information. This paper presents the physics behind, experimental results and an evaluation of the system.

  14. Ultrahigh Energy Activity in Giant Magnetar Outbursts

    E-print Network

    David Eichler

    2005-04-20

    The recent superflare of 27 December 2004 from the magnetar SGR 1806-20 was the brightest extrasolar flash ever recorded in the modern era. The chances for seeing exotic ultrahigh energy (UHE) radiation - neutrons, neutrinos, gamma rays and charged cosmic rays - from it are far better from an energetic point of view than from cosmological gamma ray bursts (GRBs). The chances for detecting the various components are discussed in light of recent data from the 27 December event.

  15. Whole Blood Activation Results in Altered T Cell and Monocyte Cytokine Production Profiles by Flow Cytometry

    NASA Technical Reports Server (NTRS)

    Crucian, Brian E.; Sams, Clarence F.

    2001-01-01

    An excellent monitor of the immune balance of peripheral circulating cells is to determine their cytokine production patterns in response to stimuli. Using flow cytometry, a positive identification of cytokine producing cells in a mixed culture may be achieved. Recently, the ability to assess cytokine production following a whole-blood activation culture has been described. In this study, whole blood activation was compared to traditional PBMC activation and the individual cytokine secretion patterns for both T cells, T cell subsets and monocytes was determined by flow cytometry. RESULTS: For T cell cytokine assessment (IFNg/IL-10 and IL-21/L-4) following PMA +ionomycin activation: (1) a Significantly greater percentages of T cells producing IFNgamma and IL-2 were observed following whole-blood culture and (2) altered T cell cytokine production kinetics were observed by varying whole blood culture times. Four-color analysiS was used to allow assessment of cytokine production by specific T cell subsets. It was found that IFNgamma production was significantly elevated in the CD3+/CD8+ T cell population as compared to the CD3+/CD8- population following five hours of whole blood activation. Conversely, IL-2 and IL-10 production were Significantly elevated in the CD3+/CD8- T cell population as compared to the CD3+/CD8+ population. Monocyte cytokine production was assessed in both culture systems following LPS activation for 24 hours. A three-color flow cytometric was used to assess two cytokines (IL-1a/IL-12 and TNFa/IL-10) in conjunction with CD14. Nearly all monocytes were stimulated to produce IL-1a, IL-12 and TNFa. equally well in both culture systems, however monocyte production of IL-10 was significantly elevated in whole blood culture as compared to PBMC culture. IL-12 producing monocytes appeared to be a distinct subpopulation of the IL-1a producing set, whereas IL-10 and TNFa producing monocytes were largely mutually exclusive. IL-10 and TNFa producing monocytes may represent distinct monocyte subsets with unique functions. CONCLUSIONS: Whole blood culture eliminates the need to purify cell populations prior to culture and may have Significant utility for the routine monitoring of the cytokine balances of the peripheral blood T cell and monocyte populations. In addition, there are distinct advantages to performing whole-blood (WB) activation as compared to PBMC activation. These advantages would include retaining all various cell-cell interactions as well as any soluble factors present in serum that influence cell activation. In this study, alterations in cytokine production are demonstrated between whole blood and PBMC activation. It is likely that whole blood activation more accurately represents the in-vivo immune balance than PBMC activation.

  16. Control of metabolic energy by space systems. Part 1: Theoretical reports of space flow structure and function

    Microsoft Academic Search

    B. L Reid; C Bourke

    2003-01-01

    In past papers, a notion emerged that space had elements common to the energy of atomic shells to which it could flow by paths to control metabolic energy of animate systems. This paper examines several authors on the structure and function of space energy wave bundle flows seeking mechanisms for metabolic control. The application of time to these waves provides

  17. A SEA-LIKE APPROACH FOR THE DERIVATION OF ENERGY FLOW COEFFICIENTS WITH A FINITE ELEMENT MODEL

    Microsoft Academic Search

    C. R. Fredö

    1997-01-01

    The Finite Element method is combined with a Statistical Energy Analysis-like (SEAL) energy flow balance to derive the power transmission between two thin plates. A fundamental difference between SEA and the SEAL procedure is that former is applied to ensembles, while the latter addresses the individual case. Energy Flow Coefficients (EFCs) are derived and explicit use of the non-resonant part

  18. Energy Conservation Activity Guide, Grades 9-12. Bulletin 1602.

    ERIC Educational Resources Information Center

    Fraser, Mollie; And Others

    As an interdisciplinary, non-sequential teaching guide, this publication was developed to increase awareness and understanding of the energy situation and to encourage individuals to become energy conservationists. Sections provide background information for the teacher followed by a variety of student activities using different subject areas for…

  19. Momentum and energy approximations for elementary squeeze-film damper flows

    NASA Astrophysics Data System (ADS)

    Crandall, S. H.; El-Shafei, A.

    1993-09-01

    To provide understanding of the effects of inertia on squeeze-film damper performance, two elementary flow patterns are studied. These elementary flows each depend on a single generalized motion coordinate whereas general planar motions of a damper are described by two independent generalized coordinates. Momentum and energy approximations for the elementary flows are compared with exact solutions. It is shown that the energy approximation, not previously applied to squeeze films, is superior to the momentum approximation in that at low Reynolds number the energy approximations agree with the exact solutions to first order in the Reynolds number whereas there are 20 percent errors in the first-order terms of the momentum approximations.

  20. National Energy Education Development: Curriculum Guides and Activities

    NSDL National Science Digital Library

    The National Energy Education Development (NEED) project develops and distributes comprehensive, hands-on energy education programs to schools nationwide. These resources are correlated to the National Science Education Standards, and to many state standards as well. Resources on this page include 'Energy Infobooks' on energy types (biomass, geothermal, uranium, coal, electricity, wind, and gas) which include downloadable teacher guides and class activities for all grade levels. Also available is the Plug Loads Booklet which guides students through an in-depth investigation of electricity usage by appliances and machines in their school building. Students gather data and calculate energy consumption and economic and environmental costs over time.

  1. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery

    PubMed Central

    Li, Bin; Nie, Zimin; Vijayakumar, M.; Li, Guosheng; Liu, Jun; Sprenkle, Vincent; Wang, Wei

    2015-01-01

    Redox flow batteries are receiving wide attention for electrochemical energy storage due to their unique architecture and advantages, but progress has so far been limited by their low energy density (~25?Wh?l?1). Here we report a high-energy density aqueous zinc-polyiodide flow battery. Using the highly soluble iodide/triiodide redox couple, a discharge energy density of 167?Wh?l?1 is demonstrated with a near-neutral 5.0?M ZnI2 electrolyte. Nuclear magnetic resonance study and density functional theory-based simulation along with flow test data indicate that the addition of an alcohol (ethanol) induces ligand formation between oxygen on the hydroxyl group and the zinc ions, which expands the stable electrolyte temperature window to from ?20 to 50?°C, while ameliorating the zinc dendrite. With the high-energy density and its benign nature free from strong acids and corrosive components, zinc-polyiodide flow battery is a promising candidate for various energy storage applications. PMID:25709083

  2. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery.

    PubMed

    Li, Bin; Nie, Zimin; Vijayakumar, M; Li, Guosheng; Liu, Jun; Sprenkle, Vincent; Wang, Wei

    2015-01-01

    Redox flow batteries are receiving wide attention for electrochemical energy storage due to their unique architecture and advantages, but progress has so far been limited by their low energy density (~25?Wh?l(-1)). Here we report a high-energy density aqueous zinc-polyiodide flow battery. Using the highly soluble iodide/triiodide redox couple, a discharge energy density of 167?Wh?l(-1) is demonstrated with a near-neutral 5.0?M ZnI2 electrolyte. Nuclear magnetic resonance study and density functional theory-based simulation along with flow test data indicate that the addition of an alcohol (ethanol) induces ligand formation between oxygen on the hydroxyl group and the zinc ions, which expands the stable electrolyte temperature window to from -20 to 50?°C, while ameliorating the zinc dendrite. With the high-energy density and its benign nature free from strong acids and corrosive components, zinc-polyiodide flow battery is a promising candidate for various energy storage applications. PMID:25709083

  3. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery

    NASA Astrophysics Data System (ADS)

    Li, Bin; Nie, Zimin; Vijayakumar, M.; Li, Guosheng; Liu, Jun; Sprenkle, Vincent; Wang, Wei

    2015-02-01

    Redox flow batteries are receiving wide attention for electrochemical energy storage due to their unique architecture and advantages, but progress has so far been limited by their low energy density (~25?Wh?l?1). Here we report a high-energy density aqueous zinc-polyiodide flow battery. Using the highly soluble iodide/triiodide redox couple, a discharge energy density of 167?Wh?l?1 is demonstrated with a near-neutral 5.0?M ZnI2 electrolyte. Nuclear magnetic resonance study and density functional theory-based simulation along with flow test data indicate that the addition of an alcohol (ethanol) induces ligand formation between oxygen on the hydroxyl group and the zinc ions, which expands the stable electrolyte temperature window to from ?20 to 50?°C, while ameliorating the zinc dendrite. With the high-energy density and its benign nature free from strong acids and corrosive components, zinc-polyiodide flow battery is a promising candidate for various energy storage applications.

  4. Measurement and analysis of energy flow in Stirling-type pulse tube refrigerator

    NASA Astrophysics Data System (ADS)

    Ki, Taekyung; Jeong, Sangkwon; Seo, Mansu; Park, Inmyong

    2012-06-01

    The analysis of energy flow is a useful method for understanding a system. This paper focuses on the instantaneous measurement of physical conditions and analysis of energy flow in the Stirling-type pulse tube refrigerator. For measuring physical conditions of the working fluid such as the mass flow rate, the temperature, and the pressure, several cryogenic sensors are installed in the Stirling-type pulse tube refrigerator optimally designed in the operating condition of 60 Hz and 2.5 MPa. The physical conditions of the working fluid in the Stirling-type pulse tube refrigerator are carefully measured as varying the operating frequency and the charging pressure. From the measured results, the enthalpy, the PV work, and the loss are quantified in each location of the PTR and the conversion of energy flows is experimentally confirmed. The results of this paper can be used for understanding the optimal operating condition and modifying correlations of various losses in the Stirling-type pulse tube refrigerator. KEYWORDS: Energy flow, Loss, Pulse tube refrigerator

  5. Effects of Surface Area and Flow Rate on Marine Bacterial Growth in Activated Carbon Columns

    PubMed Central

    Shimp, Robert J.; Pfaender, Frederic K.

    1982-01-01

    The colonization of granular activated carbon columns by bacteria can have both beneficial and potentially detrimental consequences. Bacterial growth on the carbon surface can remove adsorbed organics and thus partially regenerate the carbon bed. However, growth can also increase the levels of bacteria in the column effluents, which can adversely affect downstream uses of the treated water. This study of a sand column and several activated carbon columns demonstrated that considerable marine bacterial growth occurred in both sand and carbon columns and that this growth increased the number of bacteria in column effluents. Activated carbon supported approximately 50% more bacteria than did sand. Bacterial growth on activated carbon was reduced by increasing the flow rate through a carbon column and increasing the carbon particle size. Scanning electron micrographs showed that bacteria preferred to attach in the protected crevices on both the sand and carbon surface. The results of this study indicated that the colonization of activated carbon by marine bacteria was enhanced because of carbon's high surface area, its rough surface texture, and its ability to absorb organic materials. Images PMID:16346080

  6. Energy flow in quantum critical systems far from equilibrium

    NASA Astrophysics Data System (ADS)

    Bhaseen, M. J.; Doyon, Benjamin; Lucas, Andrew; Schalm, Koenraad

    2015-06-01

    Characterizing the behaviour of strongly coupled quantum systems out of equilibrium is a cardinal challenge for both theory and experiment. With diverse applications ranging from the dynamics of the quark-gluon plasma to transport in novel states of quantum matter, establishing universal results and organizing principles out of equilibrium is crucial. We present a universal description of energy transport between quantum critical heat baths in arbitrary dimension. The current-carrying non-equilibrium steady state (NESS) is a Lorentz-boosted thermal state. In the context of gauge/gravity duality this reveals an intimate correspondence between far-from-equilibrium transport and black hole uniqueness theorems. We provide analytical expressions for the energy current and the generating function of energy current fluctuations, together with predictions for experiment.

  7. Chemical energy release and dynamics of transitional, reactive shear flows

    NASA Astrophysics Data System (ADS)

    Grinstein, F. F.; Kailasanath, K.

    1992-10-01

    Using a numerical model, the effects of diffusive transport, chemical energy release, and the free-stream-reactant molar fraction on the development of shear-layer in a compressible subsonic chemically reacting mixing layer are investigated together with the dependence of these effects on initial conditions. The system studied consisted of a (single-frequency) forced mixing layer formed by dilute nonpremixed subsonic streams of hydrogen and oxygen, which are allowed to react with and without energy release in a nominally inviscid and a fully viscous configuration. Results show that the energy release has the effect of reducing the shear layer growth and the amount of chemical product formed, relative to the corresponding cases for which exothermicity was not accounted for.

  8. Social-psychological correlates of household energy-conservation activities

    Microsoft Academic Search

    1987-01-01

    Energy-conservation programs have been concentrated in the residential sector. An understanding of the variables that affect household energy conservation can lead to more-effective consumer energy policies. In this study, four categories of variables relevant to household conservation were examined - demographics, household structure, conservation experience and attitudes, and conservation-policy preferences. A distinction was made between two types of conservation activities

  9. Perceived surface slant is systematically biased in the actively-generated optic flow.

    PubMed

    Fantoni, Carlo; Caudek, Corrado; Domini, Fulvio

    2012-01-01

    Humans make systematic errors in the 3D interpretation of the optic flow in both passive and active vision. These systematic distortions can be predicted by a biologically-inspired model which disregards self-motion information resulting from head movements (Caudek, Fantoni, & Domini 2011). Here, we tested two predictions of this model: (1) A plane that is stationary in an earth-fixed reference frame will be perceived as changing its slant if the movement of the observer's head causes a variation of the optic flow; (2) a surface that rotates in an earth-fixed reference frame will be perceived to be stationary, if the surface rotation is appropriately yoked to the head movement so as to generate a variation of the surface slant but not of the optic flow. Both predictions were corroborated by two experiments in which observers judged the perceived slant of a random-dot planar surface during egomotion. We found qualitatively similar biases for monocular and binocular viewing of the simulated surfaces, although, in principle, the simultaneous presence of disparity and motion cues allows for a veridical recovery of surface slant. PMID:22479473

  10. The altitude effect on the climatic factors controlling debris flows activation: the Marderello Torrent case study

    NASA Astrophysics Data System (ADS)

    Palladino, Michela; Turconi, Laura; Savio, Gabriele; Tropeano, Domenico

    2015-04-01

    The left Cenischia valley includes some of the best known alpine basins prone to debris flow in Northwestern Italian Alps. In particular, in the Marderello catchment (6,6 km²), a left tributary of the Cenischia river, 31 important debris flood/flow events occurred during the last one hundred years. According to the chronicles of the last three centuries, events with significant volumes are on the average liable to take place every 3-4 years, whereas minor events may occur even twice per year. Due to the high frequency of activations, the site is of relevant interest for monitoring purposes. Since the early nineties, the CNR IRPI equipped the Marderello basin with meteorological monitoring devices. The rainfall monitoring network consists of four rain gauges, placed at different elevations, between 800 m a.s.l. and 2854 m a.s.l. Other meteorological data (air moisture and temperature, atmospheric pressure, wind speed and direction) are provided by three stations located at 3150, 2150 and 830 m a.s.l. The main objective of the monitoring is the investigation of the triggering conditions for debris flows initiation. In the scientific literature the prediction of debris flows is often tackled by the use of empirical methods, based on the analysis of past activation and related rainfall triggering conditions. The effectiveness of these methods strictly depends on the representativeness of the meteorological monitoring stations used to collect the data. In complex orography sites, as the Alpine catchments are, the remarkable elevation gaps between the source areas of debris flows and the rain gauges position make it difficult to identify the triggering rainfall. To attain more reliable results, the elevation effect must be considered. In fact, elevation influences the precipitation in terms of cumulative values and, as a result of the temperature gradient, it controls the nature of the precipitation (rain/snow). In the present study we use the rainfall and temperature monitoring data collected in the Marderello basin to investigate the effect of the elevation on the recorded precipitation. The capability to find a correlation between elevation and rainfall can be useful to have a better comprehension of triggering mechanisms, to identify the source areas and to produce reliable event predictions.

  11. Pahoehoe Flow

    USGS Multimedia Gallery

    A small active p?hoehoe flow overplating an older 'a'? flow on the upper TEB flow field. There were a few small scattered breakouts above the pali, but the majority of the surface activity was flowing through Royal Gardens and onto the coastal plain....

  12. Flow direction variations of low energy ions as measured by the ion electron sensor (IES) flying on board of Rosetta

    NASA Astrophysics Data System (ADS)

    Szegö, Karoly; Nemeth, Zoltan; Foldy, Lajos; Burch, James L.; Goldstein, Raymond; Mandt, Kathleen; Mokashi, Prachet; Broiles, Tom

    2015-04-01

    The Ion Electron Sensor (IES) simultaneously measures ions and electrons with two separate electrostatic plasma analyzers in the energy range of 4 eV- 22 keV for ions. The field of view is 90ox360o, with angular resolution 5ox45o for ions, with a sector containing the solar wind being further segmented to 5o × 5o. IES has operated continuously since early 2014. In the ion data a low energy (<50-100 eV) component is well separated from the higher energy ions. Here we analyze the arrival direction of this low energy component. The origin of these low energy ions is certainly the ionized component of the neutral gas emitted due to solar activity from comet 67P/Churiumov-Gerasimenko. The low energy component in general shows a 6h periodicity due to cometary rotation. The data show, however, that the arrival direction of the low energy ions is smeared both in azimuth and elevation, due possibly to the diverse mechanisms affecting these ions. One of these effects is the spacecraft potential (~-10V), which accelerates the ions towards the spacecraft omnidirectionally. To characterize the flow direction in azimuth-elevation, we have integrated over the lowest 8 energy channels using weighted energy: sum(counts * energy)/sum(counts); and considered only cases when the counts are above 30. When we apply higher cut for counts, the flow direction became more definite. For this analysis we use data files where the two neighbouring energy values and elevation values are collapsed; and the azimuthal resolution is 45o, that is the solar wind azimuthal segmentation is also collapsed. Here we use day 2014.09.11. as illustration. On that day a solar wind shock reached the spacecraft at about ~10 UT. After the shock transition the energy of the solar wind became higher, and after ~12 UT the flow direction of the solar wind fluctuated, sometimes by 35o. On this day Rosetta flew at about 29.3-29.6 km from the nucleus. In the azimuth-elevation plots summed over "weighted energy" (as defined above) we were able to identify two flow directions: one close to the anti-solar direction, and one perpendicular to it. The occurrence and variations of these directions are still under investigation. A possible cause of the acceleration of low energy ions along the solar wind might be that electrons produced by the ionization of neutrals are immediately picked up by the solar wind generating a polarization electric field that accelerates the ions. This effect is similar to the generation of ionospheric holes at Venus [Hartle and Grebowsky, Adv. Space Res., 4, 1995]. The acceleration perpendicular to the solar wind might be due to the v x B electric field. The variations of the low energy flow direction is analyzed in detail in the presentation.

  13. Magnetic and Thermal Energy Flow During Disruptions in DIII--D

    NASA Astrophysics Data System (ADS)

    Hyatt, A. W.; Lee, R. L.; Humphreys, D. A.; Kellman, A. G.; Taylor, P. L.; DIII-D Team; Cuthbertson, J. W.

    1996-11-01

    A plasma disruption results in the rapid loss of stored thermal and magnetic energy. We measure the spatial distribution and temporal evolution of energy flows during disruptions in DIII--D using magnetics, bolometry and toroidally separated infrared video (IRTV) cameras. Bolometer tomography and IRTV data are used to separate divertor heat flux into radiation and conduction components. A Poynting flux analysis based on the poloidal flux, ?(r,t), generated by the equilibrium reconstruction code EFIT measures the flow of electromagnetic energy into a volume defined by the vacuum chamber inner wall. The measured inflow/outflow of energy from this volume throughout a disruption's thermal and current quench phases will be presented for various types of disruptions: radiative collapse, high beta, VDE, etc. From these measurements we construct an energy balance which accounts for all energy flows to about 10%. We find that a radiative collapse disruption conducts significantly less energy to the divertor than others, and that an accurate energy balance requires toroidally asymmetric heat flux measurements.

  14. The Energy Dependence of Flow in Ni Induced Collisions from 400A to 1970A MeV

    NASA Astrophysics Data System (ADS)

    Chance, J.; Albergo, S.; Bieser, F.; Brady, F. P.; Caccia, Z.; Cebra, D.; Chacon, A. D.; Choi, Y.; Costa, S.; Elliott, J. B.; Gilkes, M.; Hauger, J. A.; Hirsch, A. S.; Hjort, E. L.; Insolia, A.; Justice, M.; Keane, D.; Kintner, J. C.; Lisa, M. A.; Matis, H. S.; McMahan, M.; McParland, C.; Olson, D. L.; Partlan, M. D.; Porile, N. T.; Potenza, R.; Rai, G.; Rasmussen, J.; Ritter, H. G.; Romanski, J.; Romero, J. L.; Russo, G. V.; Scharenberg, R.; Scott, A.; Shao, Y.; Srivastava, B.; Symons, T. J.; Tincknell, M.; Tuvé, C.; Wang, S.; Warren, P.; Wieman, H. H.; Wienold, T.; Wolf, K.

    1997-03-01

    We study the energy dependence of collective (hydrodynamic-like) nuclear matter flow in (400-1970)A MeV Ni+Au and (1000-1970)A MeV Ni+Cu reactions. The flow increases with energy, appears to reach a maximum, and then to decrease at higher energies. A way of comparing the energy dependence of flow values for different projectile-target mass combinations is introduced, which demonstrates a more-or-less common scaling behavior among flow values from different systems.

  15. Chiral nihility effects on energy flow in chiral materials

    Microsoft Academic Search

    Cheng-Wei Qiu; Nawaz Burokur; Saïd Zouhd; Le-Wei Li

    2008-01-01

    The propagation of electromagnetic plane waves in an isotropic chiral medium is characterized, and a special interest is shown in chiral nihility and the effects of chirality on energy transmission. In particular, the wave impedance is matched to that of free space. Moreover, the refractive index n is also matched in impedance to that of free space when an appropriate

  16. Energy dissipation in inelastic flow of cohesionless granular media

    Microsoft Academic Search

    Naoyuki Okada

    1992-01-01

    In a granular mass which supports the externally applied loads through contact friction, the external work is partly stored and partly dissipated by friction or other mechanisms. In many applications involving relatively small pressures and hard granules, the dissipation by frictional sliding constitutes the major energy absorbing mechanism. Based on micromechanics, it is shown that the external work supplied to

  17. Impact of Groundwater Flow and Energy Load on Multiple Borehole Heat Exchangers.

    PubMed

    Emad Dehkordi, S; Schincariol, Robert A; Olofsson, Bo

    2015-07-01

    The effect of array configuration, that is, number, layout, and spacing, on the performance of multiple borehole heat exchangers (BHEs) is generally known under the assumption of fully conductive transport. The effect of groundwater flow on BHE performance is also well established, but most commonly for single BHEs. In multiple-BHE systems the effect of groundwater advection can be more complicated due to the induced thermal interference between the boreholes. To ascertain the influence of groundwater flow and borehole arrangement, this study investigates single- and multi-BHE systems of various configurations. Moreover, the influence of energy load balance is also examined. The results from corresponding cases with and without groundwater flow as well as balanced and unbalanced energy loads are cross-compared. The groundwater flux value, 10(-7) m/s, is chosen based on the findings of previous studies on groundwater flow interaction with BHEs and thermal response tests. It is observed that multi-BHE systems with balanced loads are less sensitive to array configuration attributes and groundwater flow, in the long-term. Conversely, multi-BHE systems with unbalanced loads are influenced by borehole array configuration as well as groundwater flow; these effects become more pronounced with time, unlike when the load is balanced. Groundwater flow has more influence on stabilizing loop temperatures, compared to array characteristics. Although borehole thermal energy storage (BTES) systems have a balanced energy load function, preliminary investigation on their efficiency shows a negative impact by groundwater which is due to their dependency on high temperature gradients between the boreholes and surroundings. PMID:25227154

  18. Drainage basin morphometry controls on the active depositional area of debris flow fans

    NASA Astrophysics Data System (ADS)

    Mihir, Monika; Wasklewicz, Thad; Malamud, Bruce

    2015-04-01

    A majority of the research on understanding the connection between alluvial fans and drainage basins to date has focused on coarse-scale relations between total fan area and drainage basin area. Here we take a new approach where we assess relationships between active fan depositional area and drainage basin morphometry using 52 debris flow fans (32 from the White Mountains and 20 from the Inyo Mountains) on the eastern side of Owens Valley, California, USA. The boundaries for fans, drainage basin and active depositional areas were delineated from 10m digital elevation models and 1 m aerial photographs. We examined the relationships between the normalised active depositional area of the fan (Afad/Af, where Afad is the fan active depositional area and Af the entire fan area) and the following four variables for drainage basin: (i) area (Adb), (ii) total stream length (Ls), (iii) relief (BHH), (iv) roughness (R). We find a statistically significant (r2 > 0.40) inverse power-law relationship between recent sediment contribution to the fan and drainage basin area (Afad/Af = 0.29Adb-0.167) drainage network length (Afad/Af = 0.39Ls-0.161) and basin relief (Afad/Af = 3.90BHH-0.401), and a statistically weak (r2 = 0.22) inverse power law with basin roughness (Afad/Af = 0.32R0.5441). Drainage basin size combined with other morphometric variables may largely determine efficiency in sediment transport and delivery to the fan surface. A large proportion of the total fan area of smaller fans are flooded by debris flow indicating less sediment storage in the drainage basins and greater efficiency in sediment delivery. The findings signify the importance of coarse-scale relationships to both long- and short-term fan evolution.

  19. Fiber optic DTS in sealed and heated boreholes for active groundwater flow characterization

    NASA Astrophysics Data System (ADS)

    Coleman, Thomas; Parker, Beth; Cherry, John; Mondanos, Michael

    2013-04-01

    In recent years, advances in technology have allowed temperature profiling to evolve to offer new insight into fractured rock hydrogeology. Temperature profiles in open boreholes within fractured rock have long been used to identify and characterize flow in the rock formation and/or in the borehole. An advance in temperature logging makes use of precision temperature profiles collected using wireline trolling methods in a heated borehole to identify fractures with active groundwater flow by creating a thermal disequilibrium and monitoring the temperature response. A second development is based on collecting wireline temperature profiles within a sealed borehole to eliminate short circuiting effects caused by the open borehole conduit. The borehole is temporarily sealed with a flexible impervious fabric liner so that the water column in the borehole is static and cross-connection is eliminated. Though highly precise temperature and spatial measurements are possible using these techniques, the temporal resolution is limited by the rate at which the wireline probe can be raised and lowered in the borehole. There is a need to measure temperature profiles continuously over time to characterize transient processes. Fibre optic distributed temperature sensing (DTS) is a technique that allows for collecting temperature profiles continuously. This tool was advanced by the oil and gas industry for collecting temperature data in multi kilometer deep boreholes over relatively coarse measurement scales. In contrast, very fine spatial and temperature resolutions are needed for freshwater contaminant fractured rock hydrogeology where the scale of interest is much more acute. Recent advances in the spatial, temperature, and temporal resolution of DTS systems allow this technology to be adapted well to the shallow subsurface environment. This project demonstrates the first application of DTS used in conjunction with flexible borehole liners in a heated borehole environment. The integration of DTS, active heating, and lined boreholes was tested in the context of fractured rock site characterization. DTS heat pulse tests were carried out in two boreholes located at a well characterized research site in Guelph, ON, Canada. The capabilities for long-term and high temporal resolution site monitoring and characterization from the developed methods were assessed. The results of this technique are promising and indicate evidence for identifying active groundwater flow. Advancements to the DTS heat pulse method are possible to offer further improved insight into natural groundwater flow systems.

  20. Energy Consumption of Actively Beating Flagella

    NASA Astrophysics Data System (ADS)

    Chen, Daniel; Nicastro, Daniela; Dogic, Zvonimir

    2012-02-01

    Motile cilia and flagella are important for propelling cells or driving fluid over tissues. The microtubule-based core in these organelles, the axoneme, has a nearly universal ``9+2'' arrangement of 9 outer doublet microtubules assembled around two singlet microtubules in the center. Thousands of molecular motor proteins are attached to the doublets and walk on neighboring outer doublets. The motors convert the chemical energy of ATP hydrolysis into sliding motion between adjacent doublet microtubules, resulting in precisely regulated oscillatory beating. Using demembranated sea urchin sperm flagella as an experimental platform, we simultaneously monitor the axoneme's consumption of ATP and its beating dynamics while key parameters, such as solution viscosity and ATP concentration, are varied. Insights into motor cooperativity during beating and energetic consequences of hydrodynamic interactions will be presented.

  1. Energy-aware Activity Classification using Wearable Sensor Networks

    PubMed Central

    Dong, Bo; Montoye, Alexander; Moore, Rebecca; Pfeiffer, Karin; Biswas, Subir

    2014-01-01

    This paper presents implementation details, system characterization, and the performance of a wearable sensor network that was designed for human activity analysis. Specific machine learning mechanisms are implemented for recognizing a target set of activities with both out-of-body and on-body processing arrangements. Impacts of energy consumption by the on-body sensors are analyzed in terms of activity detection accuracy for out-of-body processing. Impacts of limited processing abilities for the on-body scenario are also characterized in terms of detection accuracy, by varying the background processing load in the sensor units. Impacts of varying number of sensors in terms of activity classification accuracy are also evaluated. Through a rigorous systems study, it is shown that an efficient human activity analytics system can be designed and operated even under energy and processing constraints of tiny on-body wearable sensors. PMID:25075266

  2. ZaP-HD: High Energy Density Z-Pinch Plasmas using Sheared Flow Stabilization

    NASA Astrophysics Data System (ADS)

    Shumlak, U.; Nelson, B. A.; Golingo, R. P.; Bowers, C. A.; Doty, S. A.; Forbes, E. G.; Goldstone, D.; Hughes, M. C.; Kim, B.; Knecht, S. D.; Lambert, K. K.; Lowrie, W.; Ross, M. P.; Weed, J. R.

    2014-10-01

    The ZaP-HD flow Z-pinch project investigates scaling the sheared flow Z-pinch to HEDP conditions by using sheared flow stabilization. Z-pinch plasmas have been produced that are 100 cm long with a 1 cm radius and are quiescent for many radial Alfven times and axial flow times. Quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes: Mach2, WARPX, and NIMROD. A sheared flow profile is observed to be coincident with the quiescent period and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements of density, flow, electron & ion temperature, and magnetic field. Wall stabilization is investigated computationally and experimentally by removing 70% of the surrounding conducting wall. The flow Z-pinch concept provides an approach to achieve HED plasmas, which are large and persist for extended durations. The new experiment, ZaP-HD, has been built to investigate this approach. Experimental results and scaling analyses are presented. This work is supported by grants from US DoE and NNSA.

  3. Tracking epithelial cell junctions in C. elegans embryogenesis with active contours guided by SIFT flow.

    PubMed

    Kang, Sukryool; Lee, Chen-Yu; Gonçalves, Monira; Chisholm, Andrew D; Cosman, Pamela C

    2015-04-01

    Quantitative analysis of cell shape in live samples is an important goal in developmental biology. Automated or semi-automated segmentation and tracking of cell nuclei has been successfully implemented in several biological systems. Segmentation and tracking of cell surfaces has been more challenging. Here, we present a new approach to tracking cell junctions in the developing epidermis of C. elegans embryos. Epithelial junctions as visualized with DLG-1::GFP form lines at the subapical circumference of differentiated epidermal cells and delineate changes in epidermal cell shape and position. We develop and compare two approaches for junction segmentation. For the first method (projection approach), 3-D cell boundaries are projected into 2D for segmentation using active contours with a nonintersecting force, and subsequently tracked using scale-invariant feature transform (SIFT) flow. The resulting 2-D tracked boundaries are then back-projected into 3-D space. The second method (volumetric approach) uses a 3-D extended version of active contours guided by SIFT flow in 3-D space. In both methods, cell junctions are manually located at the first time point and tracked in a fully automated way for the remainder of the video. Using these methods, we have generated the first quantitative description of ventral epidermal cell movements and shape changes during epidermal enclosure. PMID:24771564

  4. Global vs local energy dissipation: the energy cycle of the turbulent Von K\\'arm\\'an flow

    E-print Network

    Kuzzay, Denis; Dubrulle, Bérengère

    2015-01-01

    In this paper, we investigate the relations between global and local energy transfers in a turbulent Von K\\'arm\\'an flow. The goal is to understand how and where energy is dissipated in such a flow and to reconstruct the energy cycle in an experimental device where local as well as global quantities can be measured. We use PIV measurements and we model the Reynolds stress tensor to take subgrid scales into account. This procedure involves a free parameter that is calibrated using angular momentum balance. We then estimate the local and global mean injected and dissipated power for several types of impellers, for various Reynolds numbers and for various flow topologies. These PIV-estimates are then compared with direct injected power estimates provided by torque measurements at the impellers. The agreement between PIV-estimates and direct measurements depends on the flow topology. In symmetric situations, we are able to capture up to 90% of the actual global energy dissipation rate. However, our results become...

  5. A review of UK wind energy activities

    NASA Astrophysics Data System (ADS)

    Musgrove, P. J.

    1982-01-01

    Wind power activities in Great Britain are reviewed, including a brief summary of historical windmill usage and details of developmental efforts in large and small wind turbines. An annual average resource of 5 m/sec at 10 m has been extrapolated to predict an 8-10 m/sec resource at the hub heights of large wind turbines. Initial estimates indicate that at least half of Great Britain's annual electricity consumption can be produced from windpowered generators. The potential of offshore large WECS siting is being examined, although the wind-derived electricity from those regions are projected to cost three times that of land-based operation. Recorded wind patterns with 12-48 hr. duration have indicated that at least 20% penetration into the national grid is acceptable. A test 250 kW machine is being built as a model for a 3.7 MW machine, both intended for installation at Orkney, Scotland. Additionally, construction has begun on a 25-m diameter, vertical axis, variable geometry Musgrove wind turbine. The straight-bladed machine will produce a maximum of 130 kW, and is a prototype of multi-MW offshore units.

  6. Physical Activity Energy Expenditure in Dutch Adolescents: Contribution of Active Transport to School, Physical Education, and Leisure Time Activities

    ERIC Educational Resources Information Center

    Slingerland, Menno; Borghouts, Lars B.; Hesselink, Matthijs K. C.

    2012-01-01

    Background: Detailed knowledge about physical activity energy expenditure (PAEE) can guide the development of school interventions aimed at reducing overweight in adolescents. However, relevant components of PAEE have never been objectively quantified in this population. This study investigated the contribution of active transport to and from…

  7. Subsonic and Supersonic shear flows in laser driven high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Harding, E. C.; Drake, R. P.; Gillespie, R. S.; Grosskopf, M. J.; Kuranz, C. C.; Visco, A.; Ditmar, J. R.; Aglitskiy, Y.; Weaver, J. L.; Velikovich, A. L.; Hurricane, O. A.; Hansen, J. F.; Remington, B. A.; Robey, H. F.; Bono, M. J.; Plewa, T.

    2009-05-01

    Shear flows arise in many high-energy-density (HED) and astrophysical systems, yet few laboratory experiments have been carried out to study their evolution in these extreme environments. Fundamentally, shear flows can initiate mixing via the Kelvin-Helmholtz (KH) instability and may eventually drive a transition to turbulence. We present two dedicated shear flow experiments that created subsonic and supersonic shear layers in HED plasmas. In the subsonic case the Omega laser was used to drive a shock wave along a rippled plastic interface, which subsequently rolled-upped into large KH vortices. In the supersonic shear experiment the Nike laser was used to drive Al plasma across a low-density foam surface also seeded with a ripple. Unlike the subsonic case, detached shocks developed around the ripples in response to the supersonic Al flow.

  8. Modeling of turbulent shear flows

    NASA Technical Reports Server (NTRS)

    Liou, William W.

    1992-01-01

    The current progress is documented in the research and development of modeling techniques for turbulent shear flows. These include a two-scale model for compressible turbulent flows and a new energy transfer model. The former represents the status of the efforts to identify compressibility effects in turbulence. The energy transfer model refines a weakly nonlinear wave model developed earlier, which models directly the turbulent large structures. The objective of these activities is to develop second-order closures for compressible turbulent flows.

  9. Boltzmann rovibrational collisional coarse-grained model for internal energy excitation and dissociation in hypersonic flows.

    PubMed

    Munafò, A; Panesi, M; Magin, T E

    2014-02-01

    A Boltzmann rovibrational collisional coarse-grained model is proposed to reduce a detailed kinetic mechanism database developed at NASA Ames Research Center for internal energy transfer and dissociation in N(2)-N interactions. The coarse-grained model is constructed by lumping the rovibrational energy levels of the N(2) molecule into energy bins. The population of the levels within each bin is assumed to follow a Boltzmann distribution at the local translational temperature. Excitation and dissociation rate coefficients for the energy bins are obtained by averaging the elementary rate coefficients. The energy bins are treated as separate species, thus allowing for non-Boltzmann distributions of their populations. The proposed coarse-grained model is applied to the study of nonequilibrium flows behind normal shock waves and within converging-diverging nozzles. In both cases, the flow is assumed inviscid and steady. Computational results are compared with those obtained by direct solution of the master equation for the rovibrational collisional model and a more conventional multitemperature model. It is found that the proposed coarse-grained model is able to accurately resolve the nonequilibrium dynamics of internal energy excitation and dissociation-recombination processes with only 20 energy bins. Furthermore, the proposed coarse-grained model provides a superior description of the nonequilibrium phenomena occurring in shock heated and nozzle flows when compared with the conventional multitemperature models. PMID:25353565

  10. Energy flux fluctuations in a finite volume of turbulent flow

    E-print Network

    Mahesh Bandi; Walter Goldburg; John Cressman Jr.; Alain Pumir

    2006-07-19

    The flux of turbulent kinetic energy from large to small spatial scales is measured in a small domain B of varying size R. The probability distribution function of the flux is obtained using a time-local version of Kolmogorov's four-fifths law. The measurements, made at a moderate Reynolds number, show frequent events where the flux is backscattered from small to large scales, their frequency increasing as R is decreased. The observations are corroborated by a numerical simulation based on the motion of many particles and on an explicit form of the eddy damping.

  11. Transient unidirectional energy flow and diode-like phenomenon induced by non-Markovian environments

    E-print Network

    Jun Jing; Dvira Segal; Baowen Li; Lian-Ao Wu

    2015-07-03

    Relying on an exact time evolution scheme, we identify a novel transient energy transfer phe- nomenon in an exactly-solvable quantum microscopic model consisting of a three-level system coupled to two non-Markovian zero-temperature bosonic baths through two separable quantum channels. The dynamics of this model can be solved exactly using the quantum-state-diffusion equation formalism, demonstrating finite intervals of unidirectional energy flow across the system, typically, from the non-Markovian environment towards the more Markovian bath. Furthermore, when introducing a spatial asymmetry into the system, an analogue of the rectification effect is realized. In the long time limit, the dynamics arrives at a stationary state and the effects recede. Understanding temporal characteristics of directional energy flow will aid in designing microscopic energy transfer devices.

  12. Observation of a two-temperature ion energy distribution in regions of polar wind flow

    NASA Technical Reports Server (NTRS)

    Maier, E. J.; Hoffman, J. H.

    1974-01-01

    Study of deviations from thermal equilibrium among the ions in the ionosphere by considering that the 'light' ions H(+) and He(+) may be at a different temperature from the 'heavy' ion O(+). In particular, the case in which thermal protons are observed to be flowing relative to the assumed static ambient oxygen ions is considered. The proton flow is assumed to be along the direction of the magnetic field. Of the cases tested, it is found that the measured proton temperature is from one to ten times the measured oxygen ion temperature. Such temperature enhancements may be expected both because of the energy transfer associated with the ion flow and as a consequence of the preferential energy coupling from the light-ion distribution in the exosphere.

  13. Linear feedback control of transient energy growth and control performance limitations in subcritical plane Poiseuille flow

    E-print Network

    Martinelli, F; McKernan, J; Whidborne, J F

    2011-01-01

    Suppression of the transient energy growth in subcritical plane Poiseuille flow via feedback control is addressed. It is assumed that the time derivative of any of the velocity components can be imposed at the walls as control input, and that full-state information is available. We show that it is impossible to design a linear state-feedback controller that leads to a closed-loop flow system without transient energy growth. In a subsequent step, full-state feedback controllers -- directly targeting the transient growth mechanism -- are designed, using a procedure based on a Linear Matrix Inequalities approach. The performance of such controllers is analyzed first in the linear case, where comparison to previously proposed linear-quadratic optimal controllers is made; further, transition thresholds are evaluated via Direct Numerical Simulations of the controlled three-dimensional Poiseuille flow against different initial conditions of physical interest, employing different velocity components as wall actuation...

  14. Flow dependence of high p{sub T} parton energy loss in heavy-ion collisions

    SciTech Connect

    Renk, Thorsten; Ruppert, Joerg [Department of Physics, Duke University, P.O. Box 90305, Durham, North Carolina 27708 (United States)

    2005-10-01

    The measured transverse momentum spectra and HBT correlations of bulk (i.e., low p{sub T}) matter can be well explained by assuming that the soft sector of particles produced in ultrarelativistic heavy-ion collisions is (approximately) thermalized and undergoes collective accelerated expansion in both longitudinal and transverse direction. However, this implies that bulk matter will have a nonvanishing flow component transverse to the trajectory of a high p{sub T} partonic jets. In general, this will increase the energy loss experienced by the jet parton and modify the shape of the jet cone. In this paper, we present a systematic study of the magnitude of the additional energy loss induced by flow under realistic assumptions for the medium evolution. We argue that a perturbative QGP description may be sufficient for the measured R{sub AA} if flow during the medium evolution is taken into account properly.

  15. Common patterns of energy flow and biomass distribution on weighted food webs

    NASA Astrophysics Data System (ADS)

    Zhang, Jiang; Feng, Yuanjing

    2014-07-01

    Weights of edges and nodes on food webs which are available from the empirical data hide much information about energy flows and biomass distributions in ecosystem. We define a set of variables related to weights for each species i, including the throughflow Ti, the total biomass Xi, and the dissipated flow Di (output to the environment) to uncover the following common patterns in 19 empirical weighted food webs: (1) DGBD distributions (Discrete version of a Generalized Beta Distribution), a kind of deformed Zipf's law, of energy flow and storage biomass; (2) The allometric scaling law Ti?Xi?, which can be viewed as the counterpart of the Kleiber's 3/4 law at the population level; (3) The dissipation law Di?Ti?; and (4) The gravity law, including univariate version f?( and bivariate approvement f?Ti?1Tj?2. These patterns are very common and significant in all collected webs, as a result, some remarkable regularities are hidden in weights.

  16. Time-like flows of energy momentum and particle trajectories for the Klein-Gordon equation

    Microsoft Academic Search

    George Horton; Chris Dewdney; Alexei Nesteruk

    2000-01-01

    The Klein-Gordon equation is interpreted in the de Broglie-Bohm manner as a single-particle relativistic quantum mechanical equation that defines unique time-like particle trajectories. The particle trajectories are determined by the conserved flow of the intrinsic energy density, which can be derived from the specification of the Klein-Gordon energy-momentum tensor in an Einstein-Riemann space. The approach is illustrated by application to

  17. A direct contact condenser model for high energy laser exhaust flows

    NASA Astrophysics Data System (ADS)

    Schreiber, Hardy; Truman, C. Randall; Acebal, Robert

    1988-06-01

    A heat transfer model is developed for estimating the thermal performance of direct contact packed bed condensers operating in the effluent stream of a high energy chemical laser. Using a control volume approach, mass and energy balances are applied to the process fluids in conjunction with an empirical correlation for the condenser's volumetric heat transfer coefficient. The model is demonstrated both independently and as an extension to a steam ejector program analyzing pressure recovery of laser exhaust flows.

  18. Regional blood flow and skeletal muscle energy status in endotoxemic rats

    Microsoft Academic Search

    M. M. Jepson; M. Cox; P. C. Bates; N. J. Rothwell; M. J. Stock; E. B. Cady; D. J. Millward

    1987-01-01

    Endotoxins induce muscle wasting in part as a result of depressed protein synthesis. To investigate whether these changes reflect impaired energy transduction, blood flow, Oâ extraction, and high-energy phosphates in muscle and whole-body Oâ consumption (Voâ) have been measured. Voâ was measured for 6 h after an initial sublethal dose of endotoxin (Escherichia coli lipopolysaccharide 0.3 mg\\/100 g body wt

  19. Radial flow has little effect on clusterization at intermediate energies in the framework of the Lattice Gas Model

    E-print Network

    C. B. Das; L. Shi; S. Das Gupta

    2004-09-14

    The Lattice Gas Model was extended to incorporate the effect of radial flow. Contrary to popular belief, radial flow has little effect on the clusterization process in intermediate energy heavy-ion collisions except adding an ordered motion to the particles in the fragmentation source. We compared the results from the lattice gas model with and without radial flow to experimental data. We found that charge yields from central collisions are not significantly affected by inclusion of any reasonable radial flow.

  20. Numerical investigations of flow and energy fields near a thermoacoustic couple

    Microsoft Academic Search

    Haruko Ishikawa; David J. Mee

    2002-01-01

    The flow field and the energy transport near thermoacoustic couples are simulated using a 2D full Navier-Stokes solver. The thermoacoustic couple plate is maintained at a constant temperature; plate lengths, which are ``short'' and ``long'' compared with the particle displacement lengths of the acoustic standing waves, are tested. Also investigated are the effects of plate spacing and the amplitude of

  1. Exergy accounting of energy and materials flows in steel production systems

    Microsoft Academic Search

    Márcio Macedo Costa; Roberto Schaeffer; Ernst Worrell

    2001-01-01

    A life-cycle inventory (LCI) of steel based on exergy values is presented. Exergy accounting of energy and materials flows for distinct steel production processes — conventional integrated, semi-integrated and new integrated with smelt reduction — is used to calculate and compare exergy losses and efficiencies for each case. The exergy LCI provides an integrated measure of resources, products and wastes

  2. Self-Excited Energy Harvesting in Uniform Fluid Flows Using Piezoelectric Generators

    Microsoft Academic Search

    Dogus Akaydin; Niell Elvin; Yiannis Andreopoulos

    2010-01-01

    A novel energy harvesting configuration consisting of a circular cylinder attached to a piezoelectric beam is investigated experimentally in this study. The cylinder is attached to the free end of a cantilever beam and undergoes bending deformation due to vortex shedding under uniform fluid flow. The periodic change of strain along the piezoelectric beam generates an alternating voltage that can

  3. Modelling energy flow in the vocal tract with applications to glottal closure and opening detection

    Microsoft Academic Search

    D. M. Brookes; H. P. Loke

    1999-01-01

    The pitch-synchronous analysis that is used in several areas of speech processing often requires robust detection of the instants of glottal closure and opening. In this paper we derive expressions for the flow of acoustic energy in the lossless-tube model of the vocal tract and show how linear predictive analysis may be used to estimate the waveform of acoustic input

  4. Production of marine trematode cercariae: a potentially overlooked path of energy flow in benthic systems

    Microsoft Academic Search

    David W. Thieltges; Xavier de Montaudouin; Brian Fredensborg; K. Thomas Jensen; Janet Koprivnikar; Robert Poulin

    2008-01-01

    Parasites, in particular trematodes, are unseen but ubiquitous components of marine intertidal ecosystems. Although parasites are known to affect population dynamics and food web structure, their potential function as an unrecognized path of energy flow in these ecosystems is yet to be quantified. We use published data on rates at which trematodes produce free-swimming infec- tive larvae (cercariae) that are

  5. Study of nuclear dynamics of neutron-rich colliding pair at energy of vanishing flow

    E-print Network

    Sakshi Gautam

    2011-07-28

    We study nuclear dynamics at the energy of vanishing flow of neutron-rich systems having N/Z ratio 1.0, 1.6 and 2.0 throughout the mass range at semi central colliding geometry. In particular we study the behavior of average and maximum density with N/Z dependence of the system.

  6. Mode Conversion and Energy Partitioning at Active Volcanoes

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.; Nishimura, T.; Tsutsui, T.; Iguchi, M.

    2010-12-01

    It has recently been shown that correlations of seismic noise and coda wave provide rich information on the Green’s function between observation sites. Such technique, known as seismic interferometry, are often based on the assumption of equipartitioning, and thus the energy partitioning of diffuse waves has been widely studies from the view points of wave theory and experimental/field observations. Recently, using an active seismic experiment at Asama volcano, Japan, Yamamoto and Sato (2010) quantified the scattering characteristics of multiple scattering and conversion scattering, and pointed out that P energy from active sources is rapidly converted to S energy and it takes only a few seconds that the local energy ratio approaches the equipartition based on the radiative transfer modeling using the estimated scattering parameters. To obtain a direct evidence of mode conversion and energy partitioning in shallow heterogeneous structure of active volcanoes and have implications for seismic interferometry, we conducted a seismic array observation in Nov. 2008 as a part of an active seismic experiment at Sakurajima volcano, Japan. We deployed a small square-shaped array composed of four three-component short-period seismometers, and decomposed the observed wavefield into P and S energies. Observed seismograms are characterized by spindle-like envelopes having small P-onsets and long codas lasting for more than 10 sec, and the decomposed P and S energies show the following characteristics in high frequency bands (4-8Hz and 8-12Hz): S energy rapidly increase just after the arrival of direct P wave, and S energy exceed P energy about 2 sec after the first arrival; the ratio of P and S energies make the gradual transition to the equipartition over about 5-10 sec. These behaviors can be well explained by the radiative transfer theory including mode conversion in a medium having the mean free path of about 1km. Another interesting finding from the array observation is that the local energy ratios in ambient noise and coda wave are almost the same. The fact indicates that even the ambient noise, which is basically generated by random excitation of ballistic waves, is in equipartition state due to strong scattering in heterogeneous volcanic environment. Observed good correlation between the site amplification factors estimated from ambient noise and coda wave also supports the hypothesis that these wave fields share almost same composition. These results suggest that the mode conversion and multiple scattering have an indispensable effect on the seismic wave propagation in heterogeneous volcanic environments. We expect our results on the energy partitioning and its transition to be of help to justify the applicability of seismic interferometry and pseudo-reflection method at active volcanoes.

  7. Aqueous Lithium-Iodine Solar Flow Battery for the Simultaneous Conversion and Storage of Solar Energy.

    PubMed

    Yu, Mingzhe; McCulloch, William D; Beauchamp, Damian R; Huang, Zhongjie; Ren, Xiaodi; Wu, Yiying

    2015-07-01

    Integrating both photoelectric-conversion and energy-storage functions into one device allows for the more efficient solar energy usage. Here we demonstrate the concept of an aqueous lithium-iodine (Li-I) solar flow battery (SFB) by incorporation of a built-in dye-sensitized TiO2 photoelectrode in a Li-I redox flow battery via linkage of an I3(-)/I(-) based catholyte, for the simultaneous conversion and storage of solar energy. During the photoassisted charging process, I(-) ions are photoelectrochemically oxidized to I3(-), harvesting solar energy and storing it as chemical energy. The Li-I SFB can be charged at a voltage of 2.90 V under 1 sun AM 1.5 illumination, which is lower than its discharging voltage of 3.30 V. The charging voltage reduction translates to energy savings of close to 20% compared to conventional Li-I batteries. This concept also serves as a guiding design that can be extended to other metal-redox flow battery systems. PMID:26102317

  8. Energy Efficient Engine Low Pressure Subsystem Flow Analysis

    NASA Technical Reports Server (NTRS)

    Hall, Edward J.; Lynn, Sean R.; Heidegger, Nathan J.; Delaney, Robert A.

    1998-01-01

    The objective of this project is to provide the capability to analyze the aerodynamic performance of the complete low pressure subsystem (LPS) of the Energy Efficient Engine (EEE). The analyses were performed using three-dimensional Navier-Stokes numerical models employing advanced clustered processor computing platforms. The analysis evaluates the impact of steady aerodynamic interaction effects between the components of the LPS at design and off-design operating conditions. Mechanical coupling is provided by adjusting the rotational speed of common shaft-mounted components until a power balance is achieved. The Navier-Stokes modeling of the complete low pressure subsystem provides critical knowledge of component aero/mechanical interactions that previously were unknown to the designer until after hardware testing.

  9. Airfoil leading-edge suction and energy conservation for compressible flow

    SciTech Connect

    Amiet, R.K.

    1995-04-01

    The leading-edge suction force produced when a flat-plate airfoil at zero angle of attack encounters a vertical gust was examined for compressible flow with a time-dependent gust. A simple derivation of the thrust force shows that the acoustic energy can be calculated using compact assumptions at low frequency, but that it must be calculated non-compactly at high frequency. For a general gust, the work done on the airfoil equals the energy taken from the fluid. For a sinusoidal gust the energy contained in the incident gust equals the sum of the energy remaining in the wake, the work done on the airfoil and the acoustic energy radiated away. Also, the relative proportions of the energy going to these three energy types depend on the gust frequency.

  10. Second Activation Energy in the Fractional Quantum Hall Effect

    Microsoft Academic Search

    Junichi Wakabayashi; Satoru Sudou; Shinji Kawaji; Kazuhiko Hirakawa; Hiroyuki Sakaki

    1987-01-01

    The temperature dependence of the resistivity minima of the 2\\/3 effect in the fractional quantum Hall effect has been measured for a GaAs\\/AlGaAs heterostructure with a backside gate. The results at the highest negative gate bias have shown a single activated conduction. The systematic change of the temperature dependence controlled by the gate bias indicates that this activation energy does

  11. Stress versus temperature dependence of activation energies for creep

    NASA Technical Reports Server (NTRS)

    Freed, A. D.; Raj, S. V.; Walker, K. P.

    1992-01-01

    The activation energy for creep at low stresses and elevated temperatures is associated with lattice diffusion, where the rate controlling mechanism for deformation is dislocation climb. At higher stresses and intermediate temperatures, the rate controlling mechanism changes from dislocation climb to obstacle-controlled dislocation glide. Along with this change in deformation mechanism occurs a change in the activation energy. When the rate controlling mechanism for deformation is obstacle-controlled dislocation glide, it is shown that a temperature-dependent Gibbs free energy does better than a stress-dependent Gibbs free energy in correlating steady-state creep data for both copper and LiF-22mol percent CaF2 hypereutectic salt.

  12. Energy intake during activity enhanced video game play.

    PubMed

    Mellecker, Robin R; Lanningham-Foster, Lorraine; Levine, James A; McManus, Alison M

    2010-10-01

    The purpose of this study was to examine whether the addition of a motor component to video gaming alters energy consumption. To address this problem we used an experimental manipulation design with 9-13 year olds incorporating 'seated video game' and 'activity enhanced video game' conditions, whilst allowing snacks ad libitum. No difference in snacking between the two video gaming conditions was apparent. The children consumed 374 and 383kcalh(-1) during seated and activity enhanced video gaming, respectively. A secondary purpose was to examine consistency of energy intake during free choice video game play. We found no difference in energy intake between four 1h free choice video gaming sessions. Snacking energy intake whilst video gaming was 166% more than the calories required during resting conditions. This study has shown that the addition of a motor component to the video game environment does not alter snack energy intake. However, the high calorific consumption during both seated and activity enhanced video game play highlights the need for an active attempt to restrict snacking whilst playing video games. PMID:20655345

  13. Detection of endogenous alkaline phosphatase activity in intact cells by flow cytometry using the fluorogenic ELF-97 phosphatase substrate

    NASA Technical Reports Server (NTRS)

    Telford, W. G.; Cox, W. G.; Stiner, D.; Singer, V. L.; Doty, S. B.

    1999-01-01

    BACKGROUND: The alkaline phosphatase (AP) substrate 2-(5'-chloro-2'-phosphoryloxyphenyl)-6-chloro-4-(3H)-quinazolinone (ELF((R))-97 for enzyme-labeled fluorescence) has been found useful for the histochemical detection of endogenous AP activity and AP-tagged proteins and oligonucleotide probes. In this study, we evaluated its effectiveness at detecting endogenous AP activity by flow cytometry. METHODS: The ELF-97 phosphatase substrate was used to detect endogenous AP activity in UMR-106 rat osteosarcoma cells and primary cultures of chick chondrocytes. Cells were labeled with the ELF-97 reagent and analyzed by flow cytometry using an argon ultraviolet (UV) laser. For comparison purposes, cells were also assayed for AP using a Fast Red Violet LB azo dye assay previously described for use in detecting AP activity by flow cytometry. RESULTS: The ELF-97 phosphatase substrate effectively detected endogenous AP activity in UMR-106 cells, with over 95% of the resulting fluorescent signal resulting from AP-specific activity (as determined by levamisole inhibition of AP activity). In contrast, less than 70% of the fluorescent signal from the Fast Red Violet LB (FRV) assay was AP-dependent, reflecting the high intrinsic fluorescence of the unreacted components. The ELF-97 phosphatase assay was also able to detect very low AP activity in chick chondrocytes that was undetectable by the azo dye method. CONCLUSIONS: The ELF-97 phosphatase assay was able to detect endogenous AP activity in fixed mammalian and avian cells by flow cytometry with superior sensitivity to previously described assays. This work also shows the applicability of ELF-97 to flow cytometry, supplementing its previously demonstrated histochemical applications. Copyright 1999 Wiley-Liss, Inc.

  14. From the Cover: Context sensitivity of activity-dependent increases in cerebral blood flow

    NASA Astrophysics Data System (ADS)

    Caesar, Kirsten; Gold, Lorenz; Lauritzen, Martin

    2003-04-01

    Functional neuroimaging in humans is used widely to study brain function in relation to human disease and cognition. The neural basis of neuroimaging signals is probably synaptic activity, but the effect of context, defined as the interaction between synaptic inhibition, excitation, and the electroresponsive properties of the targeted neurons, is not well understood. We examined here the effect of interaction of synaptic excitation and net inhibition on the relationship between electrical activity and vascular signals in the cerebellar cortex. We show that stimulation of the net inhibitory parallel fibers simultaneously with stimulation of the excitatory climbing fibers leads to a further rise in total local field potentials (LFP) and cerebral blood flow (CBF) amplitudes, not a decrease, as predicted from theoretical studies. However, the combined stimulation of the parallel and climbing fiber systems produced changes in CBF and LFP that were smaller than their algebraic sum evoked by separate stimulation of either system. This finding was independent of the starting condition, i.e., whether inhibition was superimposed on a state of excitation or vice versa. The attenuation of the increases in LFP and CBF amplitudes was similar, suggesting that synaptic activity and CBF were coupled under these conditions. The result might be explained by a relative neuronal refractoriness that relates to the intrinsic membrane properties of Purkinje cells, which determine the recovery time of these cells. Our work implies that neuronal and vascular signals are context-sensitive and that their amplitudes are modulated by the electroresponsive properties of the targeted neurons.

  15. Temporal clustering analysis of cerebral blood flow activation maps measured by laser speckle contrast imaging

    NASA Astrophysics Data System (ADS)

    Wang, Zheng; Luo, Qingming

    2004-05-01

    Temporal and spatial orchestration of neurovascular coupling in the brain neuronal activity is crucial for us to comprehend mechanism of functional cerebral metabolism and pathophysiology. Laser speckle contrast imaging (LSCI) through a thinned skull over the somatosensory cortex was utilized to map the spatiotemporal characteristics of local cerebral blood flow (CBF) in anesthetized rats during sciatic nerve stimulation. Since the time course of signals from all spatial loci among the massive dataset is hard to analyze, especially for the thousands of images each of which composes of millions of pixels, we introduced a temporal clustering analysis (TCA) method, which was proved as an efficient method to analyze functional magnetic resonance imaging (fMRI) data in the temporal domain. The timing and location of CBF activation showed that contralateral hindlimb sensory cortical microflow was activated to increase promptly in less than 1 s after the onset of 2 s electrical stimulation then evolved in different discrete regions. This pattern is similar but slightly elaborated to the results obtained from laser Doppler flowmetry (LDF) and fMRI. We presented this combination to investigate interacting brain regions and provided network-level analyses, which might possibly lead to a better understanding of the nature of brain parcellation and effective connectivity.

  16. Measuring activity of endocytosis-regulating factors in T-lymphocytes by flow cytometry.

    PubMed

    Beltran-Sastre, Violeta; Navarro, Estanislau

    2015-05-01

    Elucidation of the mechanisms regulating membrane traffic of lymphocyte receptors is of great interest to manipulate the immune response, as well as for accurately delivering drugs and nanoprobes to cells. Aiming to detect and characterize regulators of endocytosis and intracellular traffic, we have modified the FACS-based endocytosis assay to measure and quantify the activity of putative endocytic regulators as EGFP chimeras. To study the activity of putative endocytosis regulators, we transfected Jurkat T-lymphocytes with EGFP-tagged constructs of the regulators to be tested. Cells were then incubated with a ?CD3(APC) antibody, and were allowed to internalize the label. After acid-washing the cells, APC fluorescence was measured by flow cytometry in cells gated for EGFP(+), as well as in their EGFP(-) (transfection-resistant) counterparts that were taken as internal controls. This approach facilitated intra- and inter-assay normalization of endocytic rates/loads by comparison with the internal control. We have used this assay to test the regulatory activity of polarity kinase EMK1, and here we substantiate a role for EMK1 in the control of receptor internalization in T-lymphocytes. The method here presented gives quantitative measures of internalization, and will facilitate the development of tools to modulate endocytic rates or the intracellular fate of internalized materials. PMID:24504563

  17. The Influence of Flow on the Concentration of Platelet Active Substances in the Vicinity of Mural Microthrombi

    Microsoft Academic Search

    GERHARD KARNER; KARL PERKTOLD

    1998-01-01

    The flow effect on the concentration of platelet active substances in the vicinity of a mural microthrombus is investigated numerically. A three-dimensional model is employed in which the mural microthrombus is modelled as a semisphere attached to a plane surface. The description of the blood flow uses the three-dimensional incompressible Navier-Stokes equations for Newtonian fluids, and the mass transport and

  18. On the ill-conditioning of the multiphase flow measurement by prompt gamma-ray neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Meric, Ilker; Johansen, Geir A.; Mattingly, J.; Gardner, R. P.

    2014-02-01

    Prompt gamma-ray neutron activation analysis (PGNAA) in conjunction with the so-called Monte Carlo library least-square (MCLLS) approach for the quantitative analysis is currently considered for rapid, non-intrusive and online measurements of multiphase oil/gas/seawater flow. The results of this work indicate that the current method would be feasible for measurements of multiphase flow provided that the ill-conditioning in the MCLLS approach could be treated appropriately.

  19. Dynamics of energy flow from CH overtone excitations: Theoretical and experimental studies of CH3C?CH

    Microsoft Academic Search

    P. Hofmann; R. B. Gerber; M. A. Ratner; L. C. Baylor; E. Weitz

    1988-01-01

    A study has been made of the vibrational energy flow mechanisms and time scales pertaining to the overtone stretch excitations of methyl and acetylenic CH stretches in propyne. Classical trajectories are used to interpret the experimental data for the overtone linewidths, as well as to analyze the role that individual modes play in determining energy flow. The full anharmonic potential

  20. A Multiperiod Generalized Network Flow Model of the U.S. Integrated Energy System: Part I—Model Description

    Microsoft Academic Search

    Ana Quelhas; Esteban Gil; James D. McCalley; Sarah M. Ryan

    2007-01-01

    This paper is the first of a two-part paper presenting a multiperiod generalized network flow model of the integrated energy system in the United States. Part I describes the modeling approach used to evaluate the economic efficiencies of the system-wide energy flows, from the coal and natural gas suppliers to the electric load centers. Under the proposed problem formulation, fuel