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1

Energy flows  

NSDL National Science Digital Library

This activity introduces students to different forms of energy, energy transformations, energy storage, and the flow of energy through systems. Students learn that most energy can be traced back to nuclear fusion on the sun.

Education, Need P.

2

Characterization of activation energy for flow in metallic glasses  

SciTech Connect

The molar volume (V{sub m}) scaled flow activation energy ({Delta}E), namely as the activation energy density {rho}{sub E}={Delta}E/V{sub m}, is proposed to describe the flow of metallic glasses. Based on the energy landscape, both the shear and bulk moduli are critical parameters accounting for the {rho}{sub E} of both homogeneous and inhomogeneous flows in metallic glasses. The expression of {rho}{sub E} is determined experimentally to be a simple expression of {rho}{sub E}=(10/11)G+(1/11)K. The energy density perspective depicts a realistic picture for the flow in metallic glasses and is suggestive for understanding the glass transition and deformation in metallic glasses.

Wang, J. Q.; Wang, W. H.; Liu, Y. H.; Bai, H. Y. [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2011-01-15

3

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

ERIC Educational Resources Information Center

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)

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

1984-01-01

4

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

NASA Astrophysics Data System (ADS)

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.

Van Der Schijff, Hermanus P.

5

Active Lava Flows  

USGS Multimedia Gallery

View of the currently active flows on the pali, east of Royal Gardens subdivision. The corresponding thermal image highlights the active flow area clearly. The active flows are traveling down the east margin of the Thanksgiving Eve Breakout (TEB) flow field. The flows are being fed by a lengthening ...

2010-06-18

6

Heat and Mass Transfer in Unsteady Rotating Fluid Flow with Binary Chemical Reaction and Activation Energy  

PubMed Central

In this study, the Spectral Relaxation Method (SRM) is used to solve the coupled highly nonlinear system of partial differential equations due to an unsteady flow over a stretching surface in an incompressible rotating viscous fluid in presence of binary chemical reaction and Arrhenius activation energy. The velocity, temperature and concentration distributions as well as the skin-friction, heat and mass transfer coefficients have been obtained and discussed for various physical parametric values. The numerical results obtained by (SRM) are then presented graphically and discussed to highlight the physical implications of the simulations. PMID:25250830

Awad, Faiz G.; Motsa, Sandile; Khumalo, Melusi

2014-01-01

7

The role of high energy photons and particles in accretion flows in active nuclei  

NASA Technical Reports Server (NTRS)

The creation of high energy pairs and photons in the conversion of gravitational to thermal energy is a process common to most accretion models for active galactic nuclei. These are two observational methods designed to explore this process: direct observations of the hot photons, through hard X-ray and gamma-ray data, and indirect observations of the energetic pairs, through their polarized, nonthermal low frequency radiation. However, interpretation of these observations in terms of the conditions in the inner accretion flow requires understanding of the various processes which modify the pair and photon distributions within the hot, dense core. These processes include opacity effects within the pair/photon plasma, Compton losses on external photons, further acceleration of the pairs and further radiation by the pairs, and the dynamic interaction of the pair/photon plasma with the surrounding gas. Current observational and theoretical work is reviewed and new directions are considered in a search for constraints on or tests of accretion models of active nuclei.

Eilek, Jean A.

1988-01-01

8

Vibrating surface actuators for active flow control  

Microsoft Academic Search

Current research has shown that aircraft can gain significant aerodynamic performance benefits from active flow control (AFC). AFC seeks to control large scale flows by exploiting natural response triggered by small energy inputs. The principal target application is download alleviation of the V-22 Osprey under the DARPA sponsored Boeing Active Flow Control System program. One method of injecting energy into

Frederick T. Calkins; Dan J. Clingman

2002-01-01

9

Productivity & Energy Flow  

E-print Network

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

Mitchell, Randall J.

10

Neuroimaging and neuroenergetics: Brain activations as information-driven reorganization of energy flows  

E-print Network

Neuroimaging and neuroenergetics: Brain activations as information-driven reorganization of energy 25 January 2010 Keywords: Neuroimaging Neuroenergetics Brain activation Cortical response Deviance detection a b s t r a c t There is increasing focus on the neurophysiological underpinnings of brain

11

US energy flow, 1991  

SciTech Connect

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.

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

1992-06-01

12

Dynamo dominated accretion and energy flow: The mechanism of active galactic nuclei  

SciTech Connect

An explanation of the magnetic fields of the universe, the central mass concentration of galaxies, the massive black hole of every galaxy, and the AGN phenomena has been an elusive goal. The authors suggest here the outlines of such a theoretical understanding and point out where the physical understanding is missing. They believe there is an imperative to the sequence of mass flow and hence energy flow in the collapse of a galactic mass starting from the first non-linearity appearing in structure formation following decoupling. This first non-linearity of a two to one density fluctuation, the Lyman-{alpha} clouds, ultimately leads to the emission spectra of the phenomenon of AGN, quasars, blazars, etc. The over-arching physical principle is the various mechanisms for the transport of angular momentum. They believe they have now understood the new physics of two of these mechanisms that have previously been illusive and as a consequence they impose strong constraints on the initial conditions of the mechanisms for the subsequent emission of the gravitational binding energy. The new phenomena described are: (1) the Rossby vortex mechanism of the accretion disk {alpha}-viscosity, and (2) the mechanism of the {alpha}-{Omega} dynamo in the accretion disk. The Rossby vortex mechanism leads to a prediction of the black hole mass and rate of energy release and the {alpha}-{Omega} dynamo leads to the generation of the magnetic flux of the galaxy (and the far greater magnetic flux of clusters) and separately explains the primary flux of energy emission as force-free magnetic energy density. This magnetic flux and magnetic energy density separately are the necessary consequence of the saturation of a dynamo created by the accretion disk with a gain greater than unity.

Colgate, S.A.; Li, H.

1998-12-31

13

The Flow of Energy  

Microsoft Academic Search

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

F. Znidarsic; G. A. Robertson

2011-01-01

14

The Flow of Energy  

NASA Astrophysics Data System (ADS)

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).

Znidarsic, F.; Robertson, G. A.

15

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

16

Food Web and Energy Flow  

NSDL National Science Digital Library

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.

Galle, Janet R.; Warren, Patricia A.

2005-01-01

17

US energy flow, 1981  

NASA Astrophysics Data System (ADS)

Flow diagrams to describe the US energy situation are given. In 1981 the energy consumption was 73 quads (or 73 times 10 to the 15th power Btu). Use was down from 75 quads in 1980. Oil continues to dominate the picture as it comprises 45% of the total energy used. Net oil use (exclusive of oil purchased for the Strategic Petroleum Reserve and Exports) fell 8%; oil imports declined 14%. In contrast to oil, use of natural gas and coal remained at 1980 levels. Decreased use of residual oils, principally for electric power generating, account for much of the drop in oil use. Increased use of coal and nuclear energy for power generation almost compensated for the decrease in use of oil in that end use. Transmitted power remained at 1980 levels. The remainder of the drop in energy usage is attributed to price driven conservation, increased efficiencies in end use and the recession that prevailed during most of the year. The share of the energy drop attributable to the recession is estimated by various analysts to be on the order of 40 to 50%.

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

1982-10-01

18

Active p?hoehoe flow  

USGS Multimedia Gallery

The active front of a p?hoehoe flow near the intersection of Pikake and Warrior Street, in the Royal Gardens subdivision. The road in the lower portion of the photo is the last remaining piece of Pikake Street. ...

2010-06-18

19

Vibrating surface actuators for active flow control  

NASA Astrophysics Data System (ADS)

Current research has shown that aircraft can gain significant aerodynamic performance benefits from active flow control (AFC). AFC seeks to control large scale flows by exploiting natural response triggered by small energy inputs. The principal target application is download alleviation of the V-22 Osprey under the DARPA sponsored Boeing Active Flow Control System program. One method of injecting energy into the flow over the V22 wings is to use an active vibrating surface on the passive seal between the wing and flapperon. The active surface is an oscillating cantilevered beam which injects fluid into the flow, similar to a synthetic jet, and interacts with the flow field. Two types of actuators, or flipperons, are explored. The first is a multilayer piezoelectric polyvinylidene fluoride cantilevered bender. The second is a single crystal piezoelectric (SCP)d31 poled wafer mounted on a cantilevered spring steel substrate. This paper details the development effort including fabrication, mechanical and electrical testing, and modeling for both types of actuators. Both flipperons were mounted on the passive seal between a 1/10th scale V22 wing and flapperon and the aerodynamic performance evaluated in low speed wind tunnel. The SCP flipperon demonstrated significant cruise benefits, with increase of 10 percent lift and 20 percent angle of attack capability. The PVDF flipperon provided a 16 percent drag reduction in the hover mode.

Calkins, Frederick T.; Clingman, Dan J.

2002-07-01

20

2007 Estimated International Energy Flows  

SciTech Connect

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.

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

2011-03-10

21

ENERGY FLOWS CLIMATE CHANGE  

E-print Network

.ecd.bnl.gov/steve #12;CO , Carbon Dioxide2 #12;THE GREENHOUSE EFFECT Global average temperature -19°C or -2 °F Global average temperature 15°C or 59°F #12;ATMOSPHERIC RADIATION Power per area Energy per time per area Unit" temperature to radiative flux. #12;GLOBAL ENERGY BALANCE Global and annual average energy fluxes in watts per

Schwartz, Stephen E.

22

Active Flow Control Activities at NASA Langley  

NASA Technical Reports Server (NTRS)

NASA Langley continues to aggressively investigate the potential advantages of active flow control over more traditional aerodynamic techniques. This paper provides an update to a previous paper and describes both the progress in the various research areas and the significant changes in the NASA research programs. The goals of the topics presented are focused on advancing the state of knowledge and understanding of controllable fundamental mechanisms in fluids as well as to address engineering challenges. An organizational view of current research activities at NASA Langley in active flow control as supported by several projects 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 are to be demonstrated either in bench-top experiments, wind-tunnel investigations, or in flight as part of the fundamental NASA R&D program and then transferred to more applied research programs within NASA, DOD, and U.S. industry.

Anders, Scott G.; Sellers, William L., III; Washburn, Anthony E.

2004-01-01

23

Fluctuation-driven directional flow of energy in biochemical cycle: Electric activation of Na,K ATPase  

NASA Astrophysics Data System (ADS)

Na,K ATPase is an ion pump which uses chemical bond energy of ATP to pump Na ion out of, and K ion into living cell thus maintaining ionic and osmotic balances of the cell. Both are uphill transport reactions. Surprisingly we have found that electric energy can also substitute chemical energy to fuel the pump activity. However, in this case only electric fields of certain waveforms, amplitudes, and frequencies are effective. Waveform, amplitude and frequency are three elements of signal. In other words, Na,K ATPase can recognize, process, and harvest energy from an oscillating or a fluctuating electric field to drive an endergonic reaction. The enzyme is a molecular transducer of electric signal. This report will describe electric activation experiment to define electric signal. Electric signal will then mixed with electric noise of broad power spectrum for experiment. Effect of white noise (WN) on the efficiency of Na,K ATPase will be investigated. It will be shown that WN of appropriate power level can improve the pump efficiency when a sub-optimal electric field is used. WN can also carry a sub-threshold signal to cross over the threshold. Stochastic resonance will be discussed in reference to these observations.

Yow Tsong, Tian

1998-03-01

24

Managing talent flow. 2006 Energy and Resources  

E-print Network

Managing talent flow. 2006 Energy and Resources Talent Pulse Survey Report Consulting #12;Executive ............................................................................... 2 Addressing the talent issue ........................................................ 7 Conclusion ................................................................ 13 Contents #12;1 Managing talent flow 2006 Energy and Resources Talent Pulse Survey Report 2006

25

Drilling an Active Pahoehoe Lava Flow  

Microsoft Academic Search

Core-Drilling of an actively inflating pahoehoe lava flow on Kilauea Volcano, Hawaii has provided new insight into the timing and causes of widely recognized petrologic variations within individual basalt flows. Seven closely spaced and successively longer cores through the crust-melt interface, along with melt samples, were recovered from a single lava flow during inflation and then throughout final solidification. Petrologic

C. Thornber; L. Keszthelyi; C. Lewis-Kenedi; M. Cazeneuve; D. Goehring

2004-01-01

26

Gradient Vector Flow Fast Geometric Active Contours  

E-print Network

for boundary extraction. To this end, we combine the geodesic active contour flow [3] and the gradient vector Terms--Boundary extraction, image segmentation, gradient vector flow, geodesic active contours, level-level geometric components such as lines, circles, and ellipses [15]. Point Distribution Models: A step further

Paragios, Nikos

27

Go with the Energy Flow  

NSDL National Science Digital Library

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.

Integrated Teaching And Learning Program

28

Energy flow in periodic thermodynamics  

E-print Network

A key quantity characterizing a time-periodically forced quantum system coupled to a heat bath is the energy flowing in the steady state through the system into the bath, where it is dissipated. We derive a general expression which allows one to compute this energy dissipation rate for a heat bath consisting of a large number of harmonic oscillators, and work out two analytically solvable model examples. In particular, we distinguish between genuine transitions effectuating a change of the systems's Floquet state, and pseudo-transitions preserving that state; the latter are shown to yield an important contribution to the total dissipation rate. Our results suggest possible driving-mediated heating and cooling schemes on the quantum level. They also indicate that a driven system does not necessarily occupy only a single Floquet state when being in contact with a zero-temperature bath.

Matthias Langemeyer; Martin Holthaus

2014-01-03

29

Observing and modeling Earths energy flows  

SciTech Connect

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{sup -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.

Stevens B.; Schwartz S.

2012-05-11

30

Energy Flow through a Paper Ecosystem.  

ERIC Educational Resources Information Center

Presented is an exercise for high school students which illustrates the principle and practice of measuring energy flow through a community. Included are worksheets, instructions, a flow diagram, and a list of ecosystem parameters. (Author/CW)

Aston, T. J.

1988-01-01

31

Redox flow cells for energy conversion  

Microsoft Academic Search

Energy storage technologies provide an alternative solution to the problem of balancing power generation and power consumption. Redox flow cells are designed to convert and store electrical energy into chemical energy and release it in a controlled fashion when required. Many redox couples and cell designs have being evaluated. In this paper, redox flow systems are compared in the light

C. Ponce de Len; A. Fras-Ferrer; J. Gonzlez-Garca; D. A. Sznto; F. C. Walsh

2006-01-01

32

Redox flow cell energy storage systems  

NASA Technical Reports Server (NTRS)

The redox flow cell energy storage system being developed by NASA for use in remote power systems and distributed storage installations for electric utilities is presented. The system under consideration is an electrochemical storage device which utilizes the oxidation and reduction of two fully soluble redox couples (acidified chloride solutions of chromium and iron) 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 take place at porous carbon felt electrodes. Redox equipment has allowed the incorporation of state of charge readout, stack voltage control and system capacity maintenance (rebalance) devices to regulate cells in a stack jointly. A 200 W, 12 V system with a capacity of about 400 Wh has been constructed, and a 2 kW, 10kWh system is planned.

Thaller, L. H.

1979-01-01

33

Specific energy and temperature determination in abrasive flow machining process  

Microsoft Academic Search

A model has been proposed for the determination of specific energy and tangential forces in abrasive flow machining (AFM) process. It accounts for the process parameters of AFM e.g., grain size, applied pressure, hardness of workpiece material, number of cycles and number of active grains. Heat transfer in AFM has also been analysed considering heat flow to the workpiece and

Rajendra K Jain; V. K Jain

2001-01-01

34

California energy flow in 1992  

SciTech Connect

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.

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

1994-04-01

35

Optimal Power Flow of Multiple Energy Carriers  

Microsoft Academic Search

This paper presents an approach for combined optimization of coupled power flows of different energy infrastructures such as electricity, gas, and district heating systems. A steady state power flow model is presented that includes conversion and transmission of an arbitrary number of energy carriers. The couplings between the different infrastructures are explicitly taken into account based on the new concept

Martin Geidl; Gran Andersson

2007-01-01

36

Flow energy harvesting -- another application of the biomimetic flapping foils  

NASA Astrophysics Data System (ADS)

Imitating fish fins and insect wings, flapping foils are usually used for biomimetic propulsion. Theoretical studies and experiments have demonstrated that through specific combinations of heaving and pitching motions, these foils can also extract energy from incoming wind or current. Compared with conventional flow energy harvesting devices based upon rotating turbines, this novel design promises mitigated impact upon the environment. To achieve the required motions, existing studies focus on hydrodynamic mode coupling, in which a periodic pitching motion is activated and a heaving motion is then generated by the oscillating lifting force. Energy extraction is achieved through a damper in the heaving direction (representing the generator). This design involves a complicated control and activation system. In addition, there is always the possibility that the energy required to activate the system exceeds the energy recovered by the generator. We have discovered that a much simpler device without activation, a 2DOF foil mounted on a rotational spring and a damper undergoing flow-induced motions can achieve stable flow energy harvesting. Using Navier-Stokes simulations we predicted different behaviors of the system during flow-induced vibrations and identified the specific requirements to achieve controllable periodic motions essential for stable energy harvesting. The energy harvesting capacity and efficiency were also determined.

Zhu, Qiang; Peng, Zhangli

2009-11-01

37

Thermal energy scavenger (flow control)  

SciTech Connect

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.

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

1981-12-22

38

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

39

Novel implementation of active structural flow control  

NASA Astrophysics Data System (ADS)

Active structural flow control has emerged as an effective way to suppress the vibration of large structures by controlling in the vicinity of the disturbances with a limited number of sensors and actuators. This is in contrast with other active structural control strategies which employ distributed sensors and actuators to provide a global control of the modes of the structure. This paper presents theoretical and experimental structural intensity control results, where the instantaneous intensity is completely taken into account in the control algorithm, i.e. all the terms are considered in the real-time control process and, in particular, the evanescent waves are considered in this approach. Moreover, both the flexural and extensional waves are taken into account in the control algorithm. As they are especially well-suited for integration into structures in order to create smart materials, piezoelectric strain sensors (PVDF) are used in the sensing approach. The structural intensity is estimated from the discrete strain measurements using a finite difference scheme. A feedforward filtered-X LMS algorithm is adapted to this energy-based control problem, involving a non-positive definite quadratic form in general. In this respect, the approach is limited to cases where the geometry is such that the intensity component will have the same sign for the control source and the primary disturbance. Experimental validation of the approach is conducted on a structure made of a beam connected to a plate, where the beam is covered with viscoelastic material. A comparison of the proposed approach is made with classical acceleration control and these results show that intensity control using strain sensors allows the error sensors to be placed closer to the control source and the primary disturbance, while preserving a good control performance.

Masson, Patrice; Audrain, Pascal; Berry, Alain; Pascal, Jean-Claude; Gazengel, Bruno

2001-08-01

40

Active flow control of subsonic flow in an adverse pressure gradient using synthetic jets and passive micro flow control devices  

NASA Astrophysics Data System (ADS)

Several recent studies have shown the advantages of active and/or passive flow control devices for boundary layer flow modification. Many current and future proposed air vehicles have very short or offset diffusers in order to save vehicle weight and create more optimal vehicle/engine integration. Such short coupled diffusers generally result in boundary layer separation and loss of pressure recovery which reduces engine performance and in some cases may cause engine stall. Deployment of flow control devices can alleviate this problem to a large extent; however, almost all active flow control devices have some energy penalty associated with their inclusion. One potential low penalty approach for enhancing the diffuser performance is to combine the passive flow control elements such as micro-ramps with active flow control devices such as synthetic jets to achieve higher control authority. The goal of this dissertation is twofold. The first objective is to assess the ability of CFD with URANS turbulence models to accurately capture the effects of the synthetic jets and micro-ramps on boundary layer flow. This is accomplished by performing numerical simulations replicating several experimental test cases conducted at Georgia Institute of Technology under the NASA funded Inlet Flow Control and Prediction Technologies Program, and comparing the simulation results with experimental data. The second objective is to run an expanded CFD matrix of numerical simulations by varying various geometric and other flow control parameters of micro-ramps and synthetic jets to determine how passive and active control devices interact with each other in increasing and/or decreasing the control authority and determine their influence on modification of boundary layer flow. The boundary layer shape factor is used as a figure of merit for determining the boundary layer flow quality/modification and its tendency towards separation. It is found by a large number of numerical experiments and the analysis of simulation data that a flow control device's influence on boundary layer quality is a function of three factors: (1) the strength of the longitudinal vortex emanating from the flow control device or devices, (2) the height of the vortex core above the surface and, when a synthetic jet is present, (3) the momentum added to the boundary layer flow.

Denn, Michael E.

41

Calculated viscosity-distance dependence for some actively flowing lavas  

NASA Technical Reports Server (NTRS)

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.

Pieri, David

1987-01-01

42

Instantaneous energy separation in a jet flow  

NASA Astrophysics Data System (ADS)

"Energy separation" is the re-distribution of the total energy in a fluid flow without external work or heat, so that some portion of the fluid has higher and other portion has lower total energy (temperature) than the surrounding fluid. The mechanism of energy separation in a free jet is investigated numerically and experimentally by obtaining predictions and measurements of the instantaneous velocity and total temperature distribution. The enhancement of energy separation by acoustic excitation is also studied. The numerical study is performed by simulating two dimensional unsteady flow and total temperature field of a plane shear layer and a circular jet with varying Reynolds number. The experimental investigation consists of the flow field measurement, flow visualization and total temperature field measurement. In the flow field measurement, the instantaneous velocity is measured to characterize the motion of the coherent structure of ring vortices and its response to acoustic excitation. The coherent structure and its response to acoustic excitation are visualized by a schlieren technique. A technique of simultaneous measurement of instantaneous velocity and total temperature is developed using two parallel constant temperature hot-wire anemometers. Comparisons of the total temperature measurement results with the flow field measurement results provide information on a link between total temperature fluctuation and the motion of the coherent structure, and the enhancement of energy separation by acoustic excitation. The results show that the frequencies of dominant total temperature fluctuation coincide with those of velocity fluctuation which represent the passing frequencies of ring vortices at given locations. These confirm that the mechanism of energy separation is induced by the motion of the coherent vortical structure which generates pressure fluctuations within the flow field. The results also indicate that the enhancement of energy separation by acoustic excitation results from vortex pairing processes which are induced by acoustic excitation. By introducing the skewness of the total temperature fluctuation, the characteristics of energy separation can be identified.

Han, Bumsoo

43

Energy spectrum of Buoyancy-driven Flows  

E-print Network

Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux $\\Pi_u$, we demonstrate that for stably stratified flows, the kinetic energy spectrum $E_u(k) \\sim k^{-11/5}$, the entropy spectrum $E_\\theta(k) \\sim k^{-7/5}$, and $\\Pi_u(k) \\sim k^{-4/5}$ (Bolgiano-Obukhov scaling). This scaling is due to the depletion of kinetic energy because of buoyancy. For weaker buoyancy in stratified flows, $E_u(k)$ follows Kolmgorov's spectrum with a constant energy flux. We also argue that for Rayleigh B\\'{e}nard convection, the Bolgiano-Obukhov scaling will not hold for the bulk flow due to the positive energy supply by buoyancy and non-decreasing $\\Pi_u(k)$.

Kumar, Abhishek; Verma, Mahendra K

2014-01-01

44

Temperature-gated thermal rectifier for active heat flow control.  

PubMed

Active heat flow control is essential for broad applications of heating, cooling, and energy conversion. Like electronic devices developed for the control of electric power, it is very desirable to develop advanced all-thermal solid-state devices that actively control heat flow without consuming other forms of energy. Here we demonstrate temperature-gated thermal rectification using vanadium dioxide beams in which the environmental temperature actively modulates asymmetric heat flow. In this three terminal device, there are two switchable states, which can be regulated by global heating. In the "Rectifier" state, we observe up to 28% thermal rectification. In the "Resistor" state, the thermal rectification is significantly suppressed (<1%). To the best of our knowledge, this is the first demonstration of solid-state active-thermal devices with a large rectification in the Rectifier state. This temperature-gated rectifier can have substantial implications ranging from autonomous thermal management of heating and cooling systems to efficient thermal energy conversion and storage. PMID:25010206

Zhu, Jia; Hippalgaonkar, Kedar; Shen, Sheng; Wang, Kevin; Abate, Yohannes; Lee, Sangwook; Wu, Junqiao; Yin, Xiaobo; Majumdar, Arun; Zhang, Xiang

2014-08-13

45

Flow injection spectrophotometric assay of ?-amylase activity  

Microsoft Academic Search

A spectrophotometric flow injection method for the determination of ?-amylase activity is proposed. The method is based on the analysis of the maltose obtained during the hydrolysis of amylose in the presence of ?-amylase and relies on the reaction of 3,5 dinitrosalicylic-acid and maltose at boiling temperatures to form a brick red coloured complex, monitored spectrophotometrically at 540nm. The method

J. F van Staden; L. V Mulaudzi

2000-01-01

46

The case study of energy flow analysis and strategy in pulp and paper industry  

Microsoft Academic Search

The pulp and paper industry is a significant consumer of fossil energy in the Taiwanese manufacturing sector. The concentration of greenhouse gases (GHG) from manufacturing factory activities and vehicle emissions has increased remarkably. Notable energy savings can be achieved in the pulp and paper industry through energy flow analysis. The aim of this paper is to analyze the energy flow

Hua-Wei Chen; Chung-Hsuan Hsu; Gui-Bing Hong

2012-01-01

47

Doping dependence of the upper critical field, superconducting current density and thermally activated flux flow activation energy in polycrystalline CeFeAsO1-xFx superconductors  

NASA Astrophysics Data System (ADS)

We report the results from resistivity and magnetic measurements on polycrystalline Ce oxypnictide (CeFeAsO1-xFx) samples where x spans from 0.13 to 0.25. We find that the orbital limiting field is as high as 150 T and it systematically decreases with increasing doping. The Maki parameter is greater than one across the phase diagram and the large Maki parameter suggests that orbital and Pauli limiting effects contribute to the upper critical field. The broadening of the superconducting transition in the resistivity data was interpreted using the thermally activated flux flow (TAFF) model where we find that the TAFF activation energy, U0(B), is proportional to B-? from 1 T to high fields, and ? does not significantly change with doping. However, U0 and the superconducting critical current, Jc, are peaked in the mid-doping region (x = 0.15-0.20), and not in the low (x < 0.15) or high doping (x > 0.20) regions. Furthermore, U0 is correlated with Jc and follows the two fluid model for granular samples.

Chong, S. V.; Williams, G. V. M.; Sambale, S.; Kadowaki, K.

2014-12-01

48

Energy Flow Models for the Steel Industry  

E-print Network

Energy patterns in the U. S. steel industry are examined using several models. First is an end-use model based on data in the 1994 Manufacturing Energy Consumption Survey (MECS). Then a seven-step process model is presented and material flow through...

Hyman, B.; Andersen, J. P.

49

Energy flow observables in hadronic collisions  

E-print Network

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.

F. Hautmann

2012-05-24

50

Energy flows : empowering New Orleans  

E-print Network

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 ...

Guiraud, Florence Nathalie

2012-01-01

51

Changing Conceptions of Activation Energy.  

ERIC Educational Resources Information Center

Provides background material which relates to the concept of activation energy, fundamental in the study of chemical kinetics. Compares the related concepts of the Arrhenius activation energy, the activation energy at absolute zero, the enthalpy of activation, and the threshold energy. (CS)

Pacey, Philip D.

1981-01-01

52

Energy flows, metabolism and translation  

PubMed Central

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

Pascal, Robert; Boiteau, Laurent

2011-01-01

53

Field Flows of Dark Energy  

SciTech Connect

Scalar field dark energy evolving from a long radiation- or matter-dominated epoch has characteristic dynamics. While slow-roll approximations are invalid, a well defined field expansion captures the key aspects of the dark energy evolution during much of the matter-dominated epoch. Since this behavior is determined, it is not faithfully represented if priors for dynamical quantities are chosen at random. We demonstrate these features for both thawing and freezing fields, and for some modified gravity models, and unify several special cases in the literature.

Cahn, Robert N.; de Putter, Roland; Linder, Eric V.

2008-07-08

54

California energy flow in 1993  

SciTech Connect

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 photo voltaic demonstration plants were in operation, but their contribution remained small.

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

1995-04-01

55

Dark energy domination in the Virgocentric flow  

NASA Astrophysics Data System (ADS)

Context. The standard ?CDM cosmological model implies that all celestial bodies are embedded in a perfectly uniform dark energy background, represented by Einstein's cosmological constant, and experience its repulsive antigravity action. Aims: Can dark energy have strong dynamical effects on small cosmic scales as well as globally? Continuing our efforts to clarify this question, we now focus on the Virgo Cluster and the flow of expansion around it. Methods: We interpret the Hubble diagram from a new database of velocities and distances of galaxies in the cluster and its environment, using a nonlinear analytical model, which incorporates the antigravity force in terms of Newtonian mechanics. The key parameter is the zero-gravity radius, the distance at which gravity and antigravity are in balance. Results: 1. The interplay between the gravity of the cluster and the antigravity of the dark energy background determines the kinematical structure of the system and controls its evolution. 2. The gravity dominates the quasi-stationary bound cluster, while the antigravity controls the Virgocentric flow, bringing order and regularity to the flow, which reaches linearity and the global Hubble rate at distances ?15 Mpc. 3. The cluster and the flow form a system similar to the Local Group and its outflow. In the velocity-distance diagram, the cluster-flow structure reproduces the group-flow structure with a scaling factor of about 10; the zero-gravity radius for the cluster system is also 10 times larger. Conclusions: The phase and dynamical similarity of the systems on the scales of 1-30 Mpc suggests that a two-component pattern may be universal for groups and clusters: a quasi-stationary bound central component and an expanding outflow around it, caused by the nonlinear gravity-antigravity interplay with the dark energy dominating in the flow component.

Chernin, A. D.; Karachentsev, I. D.; Nasonova, O. G.; Teerikorpi, P.; Valtonen, M. J.; Dolgachev, V. P.; Domozhilova, L. M.; Byrd, G. G.

2010-09-01

56

California energy flow in 1993  

NASA Astrophysics Data System (ADS)

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.

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

1995-04-01

57

Electromagnetic inertia, reactive energy, and energy flow velocity  

E-print Network

In a recent paper titled "Coherent electromagnetic wavelets and their twisting null congruences," I defined the local inertia density (I), reactive energy density (R), and energy flow velocity (v) of an electromagnetic field. These are the field equivalents of the mass, rest energy, and velocity of a relativistic particle. Thus R and I are Lorentz-invariant and |v|inertia or reactive energy behind. Generic electromagnetic fields become coherent only in the far zone. Elsewhere, their energy flows at speeds |v|energy flow in several common systems: a time-harmonic electric dipole field, a time-dependent electric dipole field, and a standing plane wave. For these fields, the energy current (Poynting vector) is too weak to carry away all of the energy, thus leaving reactive energy in its wake. For the time-dependent dipole field, we find that the energy can flow both transversally and inwards, back to the source. Neither of these phenomena show up in the usual computation of the energy transport velocity which considers only averages over one period in the time-harmonic case.

Gerald Kaiser

2011-05-24

58

Energy Adventure Center. Activity Book.  

ERIC Educational Resources Information Center

Energy activities are provided in this student activity book. They include: (1) an energy walk; (2) forms of energy in the home; (3) energy conversion; (4) constructing a solar hot dog cooker (with instructions for drawing a parabola); (5) interviewing senior citizens to learn about energy use in the past; (6) packaging materials; (7) insulation;

Carlton, Linda L.

59

Activities Handbook for Energy Education.  

ERIC Educational Resources Information Center

The purpose of this handbook is to present information about energy and to translate this information into learning activities for children. Chapter 1, "Energy: A Delicate Dilemma," presents activities intended to provide an introduction to energy and energy usage. Chapter 2, "What are the Sources of Energy?" provides background information and

DeVito, Alfred; Krockover, Gerald H.

60

Redox flow cell energy storage systems  

NASA Technical Reports Server (NTRS)

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.

Thaller, L. H.

1979-01-01

61

Quantum Processes and Energy-Momentum Flow  

E-print Network

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.

B. J. Hiley; D. Robson

2014-11-28

62

Redistribution of Kinetic Energy in Turbulent Flows  

NASA Astrophysics Data System (ADS)

In statistically homogeneous turbulent flows, pressure forces provide the main mechanism to redistribute kinetic energy among fluid elements, without net contribution to the overall energy budget. This holds true in both two-dimensional (2D) and three-dimensional (3D) flows, which show fundamentally different physics. As we demonstrate here, pressure forces act on fluid elements very differently in these two cases. We find in numerical simulations that in 3D pressure forces strongly accelerate the fastest fluid elements, and that in 2D this effect is absent. In 3D turbulence, our findings put forward a mechanism for a possibly singular buildup of energy, and thus may shed new light on the smoothness problem of the solution of the Navier-Stokes equation in 3D.

Pumir, Alain; Xu, Haitao; Boffetta, Guido; Falkovich, Gregory; Bodenschatz, Eberhard

2014-10-01

63

Localized flow control with energy deposition  

NASA Astrophysics Data System (ADS)

A series of experiments with energy deposition via laser-induced optical breakdown of air, i.e., a laser spark, have been performed. These experiments have demonstrated the possibility of using a laser spark for supersonic flow control. In the first of these experiments, Rayleigh scattering flow visualization was taken for energy deposition into quiescent air. A time sequence of images showed the post breakdown fluid motion created by the laser spark for different laser energy levels. Blast wave radius and wave speed measurements were made and correlated to five different laser energy deposition levels. Laser energy was deposited upstream of a sphere in Mach 3.45 flow. The energy was deposited one sphere diameter and 0.6 diameters upstream of the front of the sphere. The frontal surface pressure on the sphere was recorded as the laser spark perturbed region interacted with the flow about the sphere. Tests for three different energy levels and two different incident laser beam diameters were completed. It has been demonstrated that the peak surface pressure associated with the Edney IV interaction can be momentarily reduced by 30% by the interaction with the thermal spot created by the laser spark. The effects of laser energy deposition on another shock interaction phenomena were studied. Laser energy deposition was used to modify the shock structure formed by symmetric wedges at Mach 3.45 within the dual solution domain. It was demonstrated experimentally that the Mach reflection could be reduced by 80% momentarily. The numerical simulations show a transition from the stable Mach reflection to a stable regular reflection. Two energy deposition methods (electric arcing and laser energy deposition) were used to force and control compressible mixing layers of axisymmetric jets. The energy deposition forcing methods have been experimentally investigated with the schlieren technique, particle image velocimetry, Mie scattering, and static pressure probe diagnostic techniques. It was demonstrated that the laser spark (capable of 40 mJ/pulse) was more effective at inducing a large-scale structure than the electric arc (capable of 1 mJ/pulse) in the compressible shear layer. (Abstract shortened by UMI.)

Adelgren, Russell Gene

64

Anisotropic flow from AGS to LHC energies  

E-print Network

Within hydrodynamics we study the effects of the initial spatial anisotropy in non-central heavy-ion collisions on the momentum distributions of the emitted hadrons. We show that the elliptic flow measured at midrapidity in 158 A GeV/c Pb+Pb collisions can be quantitatively reproduced by hydrodynamic expansion, indicating early thermalization in the collision. We predict the excitation functions of the 2nd and 4th harmonic flow coefficients from AGS to LHC energies and discuss their sensitivity to the quark-hadron phase transition.

Peter F. Kolb; Josef Sollfrank; Ulrich Heinz

1999-06-01

65

Kinetic energy fix for low internal energy flows  

NASA Astrophysics Data System (ADS)

When the kinetic energy of a flow is dominant, numerical schemes employed can encounter difficulties due to negative internal energy. A case study with several commonly used conservative schemes (MUSCL, ENO, WENO and CE/SE) shows that high order schemes may have less ability to preserve positive internal energy (MUSCL and CE/SE), or present less accurate results (WENO and ENO) when the internal energy to kinetic energy ratio is low. By analyzing the positivity property for second-order conservative schemes with large fixed CFL number conditions for time step restriction, this paper proposes the energy consistency conditions for second-order Riemann-solver type schemes and CE/SE method. According to the said energy consistency conditions, a kinetic energy fix method which limits the magnitude of kinetic energy relative to the total energy is introduced. The numerical examples show that the kinetic energy fixed CE/SE method produces reasonable results and keeps positive internal energy for flows with very low internal energy even when a vacuum occurs.

Hu, X. Y.; Khoo, B. C.

2004-01-01

66

Science Activities in Energy: Wind Energy.  

ERIC Educational Resources Information Center

Included in this science activities energy package are 12 activities related to wind energy for elementary students. Each activity is outlined on a single card and is introduced by a question. Topics include: (1) At what time of day is there enough wind to make electricity where you live?; (2) Where is the windiest spot on your schoolground?; and

Oak Ridge Associated Universities, TN.

67

Activities report in energy science  

NASA Astrophysics Data System (ADS)

Research in energy systems; solar energy equipment; energy storage techniques; high temperature solar energy conversion and solar cells; hydrogen and cryogenic energy techniques; coating techniques; and surface analysis is summarized. High energy flow lasers; HF-excited CO2 lasers; optical resonators and radiation quality; interaction between lasers and matter; laboratory laser applications; tribology; and materials research are described. Chemico-kinetic analyses of hydrocarbons-air combustion; temperature and particle concentration measurement; and combustion simulation studies are reviewed. Chemical propulsion and manufacturing techniques; missile propulsion; combustion techniques; generation of current from hydrogen; and solar energy utilization are considered.

Holtz, Hans Joachim

68

Graphene plasmonic lens for manipulating energy flow  

NASA Astrophysics Data System (ADS)

Manipulating the energy flow of light is at the heart of modern information and communication technologies. Because photons are uncharged, it is still difficult to effectively control them by electrical means. Here, we propose a graphene plasmonic (GP) lens to efficiently manipulate energy flow by elaborately designing the thickness of the dielectric spacer beneath the graphene sheet. Different from traditional metal-based lenses, the proposed graphene plasmonic lens possesses the advantages of tunability and excellent confinement of surface plasmons. It is found that the proposed lens can be utilized to focus and collimate the GP waves propagating along the graphene sheet. Particularly, the lens is dispersionless over a wide frequency range and the performance of lens can be flexibly tuned by adjusting the bias voltage. As an application of such a lens, the image transfer of two point sources with a separation of ?0/30 is demonstrated.

Wang, Guoxi; Liu, Xueming; Lu, Hua; Zeng, Chao

2014-02-01

69

Flow energy piezoelectric bimorph nozzle harvester  

NASA Astrophysics Data System (ADS)

There is a need for a long-life power generation scheme that could be used downhole in an oil well to produce 1 Watt average power. There are a variety of existing or proposed energy harvesting schemes that could be used in this environment but each of these has its own limitations. The vibrating piezoelectric structure is in principle capable of operating for very long lifetimes (decades) thereby possibly overcoming a principle limitation of existing technology based on rotating turbo-machinery. In order to determine the feasibility of using piezoelectrics to produce suitable flow energy harvesting, we surveyed experimentally a variety of nozzle configurations that could be used to excite a vibrating piezoelectric structure in such a way as to enable conversion of flow energy into useful amounts of electrical power. These included reed structures, spring mass-structures, drag and lift bluff bodies and a variety of nozzles with varying flow profiles. Although not an exhaustive survey we identified a spline nozzle/piezoelectric bimorph system that experimentally produced up to 3.4 mW per bimorph. This paper will discuss these results and present our initial analyses of the device using dimensional analysis and constitutive electromechanical modeling. The analysis suggests that an order-of-magnitude improvement in power generation from the current design is possible.

Sherrit, Stewart; Lee, Hyeong Jae; Walkemeyer, Phillip; Hasenoehrl, Jennifer; Hall, Jeffrey L.; Colonius, Tim; Tosi, Luis Phillipe; Arrazola, Alvaro; Kim, Namhyo; Sun, Kai; Corbett, Gary

2014-04-01

70

Active Learning in Fluid Mechanics: Youtube Tube Flow and Puzzling Fluids Questions  

ERIC Educational Resources Information Center

Active-learning exercises appropriate for a course in undergraduate fluid mechanics are presented. The first exercise involves an experiment in gravity-driven tube flow, with small groups of students partaking in a contest to predict the experimental flow rates using the mechanical energy balance. The second exercise takes the form of an

Hrenya, Christine M.

2011-01-01

71

Energy efficient continuous flow ash lockhopper  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

72

Dark energy domination in the Virgocentric flow  

E-print Network

The standard \\LambdaCDM cosmological model implies that all celestial bodies are embedded in a perfectly uniform dark energy background, represented by Einstein's cosmological constant, and experience its repulsive antigravity action. Can dark energy have strong dynamical effects on small cosmic scales as well as globally? Continuing our efforts to clarify this question, we focus now on the Virgo Cluster and the flow of expansion around it. We interpret the Hubble diagram, from a new database of velocities and distances of galaxies in the cluster and its environment, using a nonlinear analytical model which incorporates the antigravity force in terms of Newtonian mechanics. The key parameter is the zero-gravity radius, the distance at which gravity and antigravity are in balance. Our conclusions are: 1. The interplay between the gravity of the cluster and the antigravity of the dark energy background determines the kinematical structure of the system and controls its evolution. 2. The gravity dominates the qu...

Chernin, A D; Nasonova, O G; Teerikorpi, P; Valtonen, M J; Dolgachev, V P; Domozhilova, L M; Byrd, G G

2010-01-01

73

Money versus Time: Evaluation of Flow Control in Terms of Energy Consumption and Convenience  

E-print Network

Flow control with the goal of reducing the skin friction drag on the fluid-solid interface is an active fundamental research area, motivated by its potential for significant energy savings and reduced emissions in the transport sector. Customarily, the performance of drag reduction techniques in internal flows is evaluated under two alternative flow conditions, i.e. at constant mass flow rate or constant pressure gradient. Successful control leads to reduction of drag and pumping power within the former approach, whereas the latter leads to an increase of the mass flow rate and pumping power. In practical applications, however, money and time define the flow control challenge: a compromise between the energy expenditure (money) and the corresponding convenience (flow rate) achieved with that amount of energy has to be reached so as to accomplish a goal which in general depends on the specific application. Based on this idea, we derive two dimensionless parameters which quantify the total energy consumption an...

Frohnapfel, Bettina; Quadrio, Maurizio

2012-01-01

74

U.S. Energy Flow -- 1995  

Microsoft Academic Search

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

H. Miller; N. Mui; A. Pasternak

1997-01-01

75

Fast incorporation of optical flow into active polygons  

Microsoft Academic Search

In this paper, we first reconsider, in a different light, the addition of a prediction step to active contour-based visual tracking using an optical flow and clarify the local computation of the latter along the boundaries of continuous active contours with appropriate regularizers. We subsequently detail our contribution of computing an optical flow-based prediction step directly from the parameters of

Gozde B. Unal; Hamid Krim; Anthony J. Yezzi

2005-01-01

76

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...

77

[Energy flow in arctic aquatic ecosystems  

SciTech Connect

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.

Schell, D.M.

1985-12-31

78

NEED Project: Primary Energy Activities  

NSDL National Science Digital Library

This free activity booklet for Grades 2-4 accompanies the NEED Project's Primary Science of Energy curriculum materials. It contains an array of multisensory games, songs, graphics, and seat activities to accompany the energy instructional unit outlined in the NEED Teacher's Guide for Primary Energy. You'll also find printable assessments with answer keys and a student self-evaluation. The NEED energy curriculum is noteworthy because students are first introduced to energy as a physical science concept before being exposed to sources of energy. Using this sequence can help learners differentiate energy forms (thermal, motion, wave, chemical) from energy sources (fossil fuels, wind, geothermal, hydroelectric). See Related Materials for a link to the Teacher's Guide for this unit. 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.

2013-04-04

79

Energy flow measurements in acoustic waves in a duct.  

PubMed

Where, how much and how efficiently the energy conversion takes place in a regenerator of a thermoacoustic engine are expressed using the axial distribution of acoustic work flow and heat flow. As a first step in determining the energy flows inside the regenerator, measuring methods of the work flow are briefly described and the experimental results in an acoustic resonator are shown. Applicability of these methods to the regenerator is discussed. PMID:16987538

Biwa, Tetsushi

2006-12-22

80

Active Boundary Layer Trip for Supersonic Flows  

NASA Astrophysics Data System (ADS)

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.

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

2009-01-01

81

Energy flow in an arctic aquatic ecosystem  

SciTech Connect

This project has been using natural isotope abundances to trace major pathways of energy flow to consumers in Imnavait Creek and the tundra ecosystem of the R4D watershed with comparative work in the coastal tundra. We are processing samples collected at the R4D intensive site over the past three years and are comparing these data with similar samples collected from the coastal plain. Our approach is to determine if carbon is accumulating in upland and coastal tundra; to determine the role of eroded peat carbon in the aquatic ecosystem; and to determine the distribution of carbon and nitrogen isotopes in the tundra-pond ecosystem to establish the feasibility of using natural differences as tracers.

Schell, D.M.

1993-01-01

82

Energy flow in an arctic aquatic ecosystem  

SciTech Connect

This project has been using natural isotope abundances to trace major pathways of energy flow to consumers in Imnavait Creek and the tundra ecosystem of the R4D watershed with comparative work in the coastal tundra. We are processing samples collected at the R4D intensive site over the past three years and are comparing these data with similar samples collected from the coastal plain. Our approach is to determine if carbon is accumulating in upland and coastal tundra; to determine the role of eroded peat carbon in the aquatic ecosystem; and to determine the distribution of carbon and nitrogen isotopes in the tundra-pond ecosystem to establish the feasibility of using natural differences as tracers.

Schell, D.M.

1993-05-01

83

U.S. energy flow, 1992  

SciTech Connect

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.

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

1993-10-01

84

Analysis of flow cytometry DNA damage response protein activation kinetics after exposure to x rays and high-energy iron nuclei.  

PubMed

We developed a mathematical method to analyze flow cytometry data to describe the kinetics of ?-H2AX and pATF2 phosphorylation in normal human fibroblast cells after exposure to various qualities of low-dose radiation. Previously reported flow cytometry kinetics 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 revealed significant differences between control and low-dose samples when distributions were compared using the Kolmogorov-Smirnov test. Differences in radiation quality were found in the distribution shapes and when a nonlinear model was used to relate dose and time to the decay of the mean ratio of phospho-protein 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 ?-H2AX were higher after exposure to iron nuclei compared to X rays in G(1) cells and in S/G(2) cells. The RBE in G(1) cells for iron nuclei relative to X rays for ?-H2AX was 2.1 0.6 and 5.0 3.5 at 2 and 24 h after irradiation, respectively. For pATF2, a saturation effect was observed with reduced expression at high doses, especially for iron nuclei, with much slower characteristic repair times (>7 h) compared to X rays. RBEs for pATF2 were 0.7 0.1 and 1.7 0.5 at 2 and 24 h, respectively. Significant differences in ?-H2AX and pATF2 levels when irradiated samples were compared to controls were noted even at the lowest dose analyzed (0.05 Gy). These results show that mathematical models can be applied to flow cytometry data to identify important and subtle differences after exposure to various qualities of low-dose radiation. PMID:21128792

Chappell, Lori J; Whalen, Mary K; Gurai, Sheena; Ponomarev, Artem; Cucinotta, Francis A; Pluth, Janice M

2010-12-01

85

Army tests show stack flow restrictors save little energy  

SciTech Connect

Government performance tests of flue-stack flow restrictors made by Thermiser Ltd. and Thrifty Vents show only minor improvement in the efficiency of gas-fired furnaces. The Army tested the devices as a guideline for army bases after approaches by several vendors, and will soon release its full report on 288 separate tests. Both products are designed to reduce the amount of air to be heated. Furnace derating had the greatest effect on efficiency during the tests. Similar tests by the Naval Energy and Environmental Support Activity showed no significant savings. Both the Army and Navy tests are challenged by the manufacturers. (DCK)

Galvin, C.

1982-10-04

86

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...

87

Groundwater flow with energy transport and waterice phase change: Numerical simulations, benchmarks, and application to  

E-print Network

control heat transport, groundwater flow, and bio- logical activity. Temperature was measured over oneGroundwater flow with energy transport and water­ice phase change: Numerical simulations the transport of heat within the peat profile, the U.S. Geological Survey's SUTRA computer code was modified

Long, Bernard

88

ERDA's Fossil Energy Activities  

ERIC Educational Resources Information Center

The intended coordinative role of the Council on Environmental Quality (CEQ), as defined under the National Environmental Policy Act, is compared and contrasted with its actual activities since its formation in 1969. The Council on Environmental Quality's success has been varied and is subject to dispute. (BT)

White, Philip C.

1976-01-01

89

Energy flow in an arctic aquatic ecosystem  

SciTech Connect

Natural isotope abundances to trace major pathways of energy flow to consumers in Imnavait Creek and the tundra ecosystem of the R4D watershed with comparative work in the coastal tundra. Our overall goals are to a determine if carbon is accumulating in upland and coastal tundra; determine the role of eroded peat carbon in the aquatic ecosystem; and to determine the distribution of carbon and nitrogen isotopes in the tundra-pond ecosystem to establish the feasibility of using natural differences as tracers. Past work on fishes, birds, and the prey species of insects and aquatic crustaceans has shown that peat carbon is very important in the energy supply supporting the food webs over the course of the year. Obligate freshwater fishes from the coastal lakes and Colville River have been shown to contain up to 60 percent peat carbon at the end of the winter season. In contrast, migratory shorebirds and passerines contained much smaller radiocarbon abundances in summer, indicating a major shift to recent in situ primary production in pond and stream ecosystems in summer months. For the past two years, we have narrowed our focus to the processes supplying carbon to the beaded stream system at MS-117 and have concentrated on determining the transfer and accumulation rates of carbon in the watershed.

Schell, D.M.

1988-12-31

90

Energy flow in an arctic aquatic ecosystem  

SciTech Connect

Natural isotope abundances to trace major pathways of energy flow to consumers in Imnavait Creek and the tundra ecosystem of the R4D watershed with comparative work in the coastal tundra. Our overall goals are to a determine if carbon is accumulating in upland and coastal tundra; determine the role of eroded peat carbon in the aquatic ecosystem; and to determine the distribution of carbon and nitrogen isotopes in the tundra-pond ecosystem to establish the feasibility of using natural differences as tracers. Past work on fishes, birds, and the prey species of insects and aquatic crustaceans has shown that peat carbon is very important in the energy supply supporting the food webs over the course of the year. Obligate freshwater fishes from the coastal lakes and Colville River have been shown to contain up to 60 percent peat carbon at the end of the winter season. In contrast, migratory shorebirds and passerines contained much smaller radiocarbon abundances in summer, indicating a major shift to recent in situ primary production in pond and stream ecosystems in summer months. For the past two years, we have narrowed our focus to the processes supplying carbon to the beaded stream system at MS-117 and have concentrated on determining the transfer and accumulation rates of carbon in the watershed.

Schell, D.M.

1988-01-01

91

Field Experiments on Active Kilauea Lava Flows to Improve Cooling Models for Pahoehoe Lava Flows  

Microsoft Academic Search

Previous attempts to model the cooling of pahoehoe lava flows have shown that uncertainties in the cooling by the wind and non-equilibrium crystallization caused significant errors. New analyses of field data collected over the past decade from active pahoehoe flows on Kilauea Volcano, Hawaii, have helped reduce these uncertainties. Field measurements of the cooling of pahoehoe surfaces by the wind

L. Keszthelyi; C. Thornber; A. Harris; K. Sharma

2004-01-01

92

Active Flow Control on a Low Aspect Ratio Finite Cylinder  

NASA Astrophysics Data System (ADS)

Oftentimes, flow control about bluff bodies is investigated using quasi-2D shapes that ignore end effects, whereas real world objects are finite and thus exhibit significant three-dimensional flow fields. Therefore, synthetic-jets-based active flow control was studied on a finite cylinder of low aspect ratio (AR = 3), which incorporates large-scale end effects that must be taken into consideration. Surface pressure measurements indicated that the flow field was significantly modified by the activation of the synthetic jet actuators, when compared to the unforced case. Even with a small momentum input, the synthetic jets induce a large spanwise effect (i.e., along the cylinder span). This large scale alteration of the flow field was confirmed visually using time-averaged stereoscopic PIV measurements in the near wake, showing significant wake narrowing and vectoring, along with changes to vorticity concentrations and turbulent quantities.

Demauro, Edward; Leong, Chia Min; Amitay, Michael

2011-11-01

93

Integrated and spectral energy flows of the GLAS GCM  

NASA Technical Reports Server (NTRS)

Methods to analyze the generation, transport, and dissipation of energy to study geophysical fluid flows are discussed. Energetics analyses are pursued in several directions: (1) the longitudinal and time dependence on the energy flow to the stratosphere was examined as a function of geographical sector; (2) strong and weak energy flows were correlated by medium range forecasts; (3) the one dimensional spectral results (Fourier services around latitude circles) were extended to spherical harmonics over a global domain; (4) the validity of vertical velocities derived from mass convergence was examined for their effect on the conversion of eddy available potential energy to eddy kinetic energy.

Tennebaum, J.

1981-01-01

94

Modelling flow dynamics in an active submarine channel  

NASA Astrophysics Data System (ADS)

A novel 2.5D shallow water model, incorporating vertical stratification of flow density and velocity, has been developed to investigate the hydro- and morphodynamics of submarine meandering systems. Successfully verified against rigorous analytical and numerical test cases, the model has been applied to investigate the flow dynamics within an active submarine channel, formed at the exit of the Strait of Bosphorous in the SW Black Sea. Further, the model has been verified by comparing predicted flow hydrodynamic conditions, including velocity, density and stratification, to equivalent data directly observed within the Black Sea submarine channel. Development of the model has highlighted the importance of stratification as a primary control on submarine flow hydrodynamics. Data obtained from the Black Sea submarine channel system, and the model presented herein, demonstrates that in submarine systems density stratification acts to keep the majority of the flow bounded within the channel system, with a dilute mixing layer forming above the channel boundaries. As stratification diminishes, flow overspill from the channel increases, suggesting a degree of topographic control of flow stratification not accounted for in current empirical models of submarine flow dynamics. We also highlight the fundamental differences in flow dynamics between poorly stratified saline density currents and highly stratified turbidity currents. Specifically, we suggest that flow stratification enables turbidity currents to be contained more readily within their channel systems and therefore to develop over longer distances than equivalent saline density currents.

Dorrell, Robert; Darby, Steve; Peakall, Jeff; Parsons, Dan; Sumner, Esther; Wynn, Russell

2013-04-01

95

Directed and elliptic flow in Au + Au at intermediate energies  

E-print Network

Directed and elliptic flow for the Au + Au system at incident energies between 40 and 150 MeV per nucleon has been measured using the INDRA 4 pi multi-detector. For semi-central collisions, the elliptic flow of Z <= 2 particles switches from in-plane to out-of-plane enhancement at around 100 MeV per nucleon, in good agreement with the result reported by the FOPI Collaboration. The directed flow changes sign at a bombarding energy between 50 and 60 MeV per nucleon and remains negative at lower energies. The conditions for the appearance and possible origins of negative flow are discussed.

J. Lukasik; G. Auger; M. L. Begemann-Blaich; N. Bellaize; R. Bittiger; F. Bocage; B. Borderie; R. Bougault; B. Bouriquet; J. L. Charvet; A. Chbihi; R. Dayras; D. Durand; J. D. Frankland; E. Galichet; D. Gourio; D. Guinet; S. Hudan; P. Lautesse; F. Lavaud; A. Le Fevre; R. Legrain; O. Lopez; U. Lynen; W. F. J. Mueller; L. Nalpas; H. Orth; E. Plagnol; E. Rosato; A. Saija; C. Schwarz; C. Sfienti; B. Tamain; W. Trautmann; A. Trzcinski; K. Turzo; E. Vient; M. Vigilante; C. Volant; B. Zwieglinski

2004-10-20

96

A Field Course Based on the Community Energy Flow Approach  

ERIC Educational Resources Information Center

The concept of community energy flow provides a basis for a field course. This paper describes the methodology used in a field course for estimating parameters and for monitoring physical environmental variables. The paper culminates in the construction of a model of energy flow through the community. (Author/MA)

Townsend, Colin; Phillipson, John

1977-01-01

97

On the energy of inviscid singular flows Roman Shvydkoy 1  

E-print Network

On the energy of inviscid singular flows Roman Shvydkoy 1 Department of Mathematics, Stat. and Comp flows u t + (u · )u = - p, (1) · u = 0. (2) Email address: shvydkoy@math.uic.edu (Roman Shvydkoy). 1 is a divergence-free velocity field, and p is the internal pressure. The classi- cal law of energy conservation |u

Shvydkoy, Roman

98

Gradient Flows and Geometric Active Contour Models  

Microsoft Academic Search

Abstract: this paper. In Section 2, we discuss some of therelevant facts from Euclidean curve shortening. In Section 3, we present our modification ofthe Euclidean arc-length and the resulting active contour models. In Section 4, we considerhow these models may be extended to surfaces, i.e., for deformable surface (or 3-D contour)models. Next in Section 5, we consider the existence and

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

1995-01-01

99

The active lava flows of Kilauea volcano, Hawaii  

Microsoft Academic Search

Kilauea volcano in the Hawaiian Islands, Pacific Ocean, is the worlds most active volcano. Observations of active lava flows\\u000a of Kilauea have a great relevance to studies of older, extinct volcanic systems, such as those found in India.

Hetu Sheth

2003-01-01

100

Transport of energy by disturbances in arbitrary steady flows  

Microsoft Academic Search

An exact equation governing the transport of energy associated with disturbances in an arbitrary steady flow is derived. The result is a generalization of the familiar concept of acoustic energy and is suggested by a perturbation expansion of the general energy equation of fluid mechanics. A disturbance energy density and flux are defined and identified as exact fluid dynamic quantities

M. K. Myers

1991-01-01

101

Energy flow analysis in pulp and paper industry  

Microsoft Academic Search

This work analyzed the energy flow of the pulp and paper industry in Taiwan. The potential technology options that were examined focus on how to capture some of the energy currently lost in the processes and then identifying the areas with energy-saving potential that could also have large impacts across a variety of industries. In addition, the energy-saving potential of

Gui-Bing Hong; Chih-Ming Ma; Hua-Wei Chen; Kai-Jen Chuang; Chang-Tang Chang; Te-Li Su

2011-01-01

102

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

PubMed Central

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

Aradag, Selin

2013-01-01

103

Wind energy activities in Japan  

Microsoft Academic Search

This paper describes recent activities on wind energy in Japan. The national Sunshine Project conducted by the Ministry of International Trade and Industry, was reviewed in 1990 to map out a new energy strategy in the Age of Global Environment. As a result, a new 500kW WECS R&D project has started in FY1991 and the operation started in FY1996. A

Izumi Ushiyama

1999-01-01

104

Closed-Loop Active Flow Control Systems: Actuators  

Microsoft Academic Search

Closed-loop active flow control (CLAFC), the capability to estimate, efficiently alter and maintain a flow state, relies on the control authority of available actuators as a primary enabling technology. The requirements from the actuation\\u000a systems are outlined and a critical review of available actuation technology is offered. Since the relevance of a given actuator\\u000a depends on the application, separation control

A. Seifert

105

Underwater observations of active lava flows from Kilauea volcano, Hawaii  

Microsoft Academic Search

Underwater observation of active submarine lava flows from Kilauea volcano, Hawaii, in March-June 1989 revealed both pillow lava and highly channelized lava streams flowing down a steep and unconsolidated lava delta. The channelized streams were 0.7-1.5 m across and moved at rates of 1-3 m\\/s. The estimated flux of a stream was 0.7 m3\\/s. Jets of hydrothermal water and gas

Gordon W. Tribble

1991-01-01

106

Research of Metal Flow Behavior during Extrusion with Active Friction  

NASA Astrophysics Data System (ADS)

Using numerical simulation and experiment, the metal flow behavior mechanical mechanisms in the extrusion process with active friction were investigated. The characteristic variables, second invariant of the stress deviator J 2 and the Lodes coefficient ? were employed to partition the deformation region. It is shown that no metal flow interface occurred at the container bottom in the extrusion with active friction and the dead zone disappeared completely. The strain types of the material in the plastic deformation area decreased from three types into a single type of tension, and the homogeneity of metal deformation as well as metal flow was greatly improved. It was also indicted that the active friction was beneficial to the extrusion process and the promotion of product quality. After contrasting the result of experiment and the simulation, the displacement and the load were well correlated on both values and trends.

Li, Feng; Yuan, S. J.; Liu, G.; He, Z. B.

2008-02-01

107

Anisotropic energy flow and allosteric ligand binding in albumin  

PubMed Central

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

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

2014-01-01

108

Harvesting energy from water flow over graphene.  

PubMed

Water flow over carbon nanotubes has been shown to generate an induced voltage in the flow direction due to coupling of ions present in water with free charge carriers in the nanotubes. However, the induced voltages are typically of the order of a few millivolts, too small for significant power generation. Here we perform tests involving water flow with various molarities of hydrochloric acid (HCl) over few-layered graphene and report order of magnitude higher induced voltages for graphene as compared to nanotubes. The power generated by the flow of ?0.6 M HCl solution at ?0.01 m/sec was measured to be ?85 nW for a ?30 16 ?m size graphene film, which equates to a power per unit area of ?175 W/m(2). Molecular dynamics simulations indicate that the power generation is primarily caused by a net drift velocity of adsorbed Cl(-) ions on the continuous graphene film surface. PMID:21749100

Dhiman, Prashant; Yavari, Fazel; Mi, Xi; Gullapalli, Hemtej; Shi, Yunfeng; Ajayan, Pulickel M; Koratkar, Nikhil

2011-08-10

109

Active flow control on a 1:4 car model  

NASA Astrophysics Data System (ADS)

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 %).

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

2014-05-01

110

Active Flow Effectors for Noise and Separation Control  

NASA Technical Reports Server (NTRS)

New flow effector technology for separation control and enhanced mixing is based upon shape memory alloy hybrid composite (SMAHC) technology. The technology allows for variable shape control of aircraft structures through actively deformable surfaces. The flow effectors are made by embedding shape memory alloy actuator material in a composite structure. When thermally actuated, the flow effector def1ects into or out of the flow in a prescribed manner to enhance mixing or induce separation for a variety of applications, including aeroacoustic noise reduction, drag reduction, and f1ight control. The active flow effectors were developed for noise reduction as an alternative to fixed-configuration effectors, such as static chevrons, that cannot be optimized for airframe installation effects or variable operating conditions and cannot be retracted for off-design or fail-safe conditions. Benefits include: Increased vehicle control, overall efficiency, and reduced noise throughout all f1ight regimes, Reduced flow noise, Reduced drag, Simplicity of design and fabrication, Simplicity of control through direct current stimulation, autonomous re sponse to environmental heating, fast re sponse, and a high degree of geometric stability. The concept involves embedding prestrained SMA actuators on one side of the chevron neutral axis in order to generate a thermal moment and def1ect the structure out of plane when heated. The force developed in the host structure during def1ection and the aerodynamic load is used for returning the structure to the retracted position. The chevron design is highly scalable and versatile, and easily affords active and/or autonomous (environmental) control. The technology offers wide-ranging market applications, including aerospace, automotive, and any application that requires flow separation or noise control.

Turner, Travis L.

2011-01-01

111

The Redox flow system for solar photovoltaic energy storage  

NASA Technical Reports Server (NTRS)

A new method of storage was applied to a solar photovoltaic system. The storage method is a redox flow system which utilizes the oxidation-reduction capability of two soluble electrochemical redox couples for its storage capacity. The particular variant described separates the charging and discharging function of the system such that the electrochemical couples are simultaneously charged and discharged in separate parts of the system. The solar array had 12 solar cells; wired in order to give a range of voltages and currents. The system stored the solar energy so that a load could be run continually day and night. The main advantages of the redox system are that it can accept a charge in the low voltage range and produce a relatively constant output regardless of solar activity.

Odonnell, P.; Gahn, R. F.

1976-01-01

112

ActivityFlow: Towards Incremental Specification and Flexible Coordination of Workflow Activities  

Microsoft Academic Search

. We introduce the ActivityFlow specification language for incrementalspecification and flexible coordination of workflow activities.The most interesting features of the ActivityFlow specification languageinclude (1) a collection of specification mechanisms, which provides aworkflow designer with a uniform workflow specification interface todescribe different types (i.e., ad-hoc, administrative, or production) ofworkflows involved in their organizational processes, and helps to...

Ling Liu; Calton Pu

1997-01-01

113

Activity flow: Towards incremental specification and flexible coordination of workflow activities  

Microsoft Academic Search

We introduce the ActivityFlow specification language for incremental specification and flexible coordination of workflow activities. The most interesting features of the ActivityFlow specification language include (1) a collection of specification mechanisms, which provides a workflow designer with a uniform workflow specification interface to describe difFerent types (i.e., ad-hoc, administrative, or production) of workflows involved in their organizational processes, and helps

Ling Liu; Calton Pu

114

The Energy Transformation Limit Theorem for Gas Flow Systems  

E-print Network

The limit energy theorem which determines the possibility of transformation the energy flow in power systems in the absence of technical work is investigated and proved for such systems as gas lasers and plasmatrons, chemical gas reactors, vortex tubes, gas-acoustic and other systems, as well as a system of close stars. In the case of the same name ideal gas in the system the maximum ratio of energy conversion effectiveness is linked to the Carnot theorem, which in its turn is connected with the Nernst theorem. However, numerical analyses show that the class of flow energy systems is non-carnot one. The ratio of energy conversion effectiveness depends on the properties of the working medium; a conventional cycle in open-circuit is essentially irreversible. The proved theorem gives a more strongly worded II law of thermodynamics for the selected class of flow energy systems. Implications for astrophysical thermodynamic systems and the theory of a strong shock wave are discussed.

Volov, V T

2011-01-01

115

Flow effects on jet energy loss with detailed balance  

NASA Astrophysics Data System (ADS)

In the presence of collective flow a new model potential describing the interaction of the hard jet with scattering centers is derived based on the static color-screened Yukawa potential. The flow effect on jet quenching with detailed balance is investigated in pQCD. It turns out, considering the collective flow with velocity $v_z$ along the jet direction, the collective flow decreases the LPM destructive interference comparing to that in the static medium. The gluon absorption plays a more important role in the moving medium. The collective flow increases the energy gain from gluon absorption, however, decreases the energy loss from gluon radiation, which is $(1 - v_z )$ times as that in the static medium to the first order of opacity. In the presence of collective flow, the second order in opacity correction is relatively small compared to the first order. So that the total effective energy loss is decreased. The flow dependence of the energy loss will affect the suppression of high $p_T$ hadron spectrum and anisotropy parameter $v_2$ in high-energy heavy-ion collisions.

Cheng, Luan; Liu, Jia; Wang, EnKe

2014-11-01

116

Flow effects on jet energy loss with detailed balance  

NASA Astrophysics Data System (ADS)

In the presence of collective flow a new model potential describing the interaction of the hard jet with scattering centers is derived based on the static color-screened Yukawa potential. The flow effect on jet quenching with detailed balance is investigated in pQCD. It turns out, considering the collective flow with velocity v z along the jet direction, the collective flow decreases the LPM destructive interference comparing to that in the static medium. The gluon absorption plays a more important role in the moving medium. The collective flow increases the energy gain from gluon absorption, however, decreases the energy loss from gluon radiation, which is (1 - v z ) times as that in the static medium to the first order of opacity. In the presence of collective flow, the second order in opacity correction is relatively small compared to the first order. So that the total effective energy loss is decreased. The flow dependence of the energy loss will affect the suppression of high p T hadron spectrum and anisotropy parameter v 2 in high-energy heavy-ion collisions.

Cheng, Luan; Liu, Jia; Wang, EnKe

2014-09-01

117

Numerical simulations of laser energy deposition for supersonic flow control  

NASA Astrophysics Data System (ADS)

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 study. It was designed to predict the fluid dynamic effects of the energy deposition process in supersonic flows. The numerical model captures the key physical processes, including inverse bremsstrahlung absorption, evolution of the plasma shape and structure, air breakdown chemistry and the subsequent fluid dynamics. The model was validated and its constants were calibrated using measurements of experiments performed in quiescent air. The calibrated values of the model constants were found to accurately predict the energy absorbed by the laser spark for the different focal lengths of the converging lens; over a range of incident laser pulse energies and ambient pressures. The numerical model for energy absorption was used to deposit energy in supersonic flows. The supersonic flows considered were simplified models which mimic critical flow conditions encountered by a high speed air vehicle. First, the effects of energy deposition in three-dimensional supersonic flow past a sphere and a flow with Edney Type IV shock-shock interaction were studied. The energy deposition was found to be effective in reducing the peak surface pressure, but not as effective in lowering the surface heat transfer rate. Next, the effect of laser energy deposition on the Mach reflection of two symmetric crossing shock waves in the dual solution domain was studied. Various flow configurations (Mach number and shock angle) were considered for the energy deposition. The simulations showed that the perturbation brought about by the spark led to a transition from Mach reflection to regular reflection for certain flow configurations. Multiple sparks were used to increase the degree of perturbation for cases where no transition occurred due to a single spark. This resulted in a further reduction in the dimensions of the Mach stem, but did not lead to transition.

Kandala, Ramnath

118

Closed-Loop Active Flow Control - A Collaborative Approach  

Microsoft Academic Search

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

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

2003-01-01

119

Stochastic simulation of active grain density in abrasive flow machining  

Microsoft Academic Search

Abrasive flow machining can be applied to an impressive range of finishing operations economically and effectively. Both theoretical and experimental studies of the media topography are greatly hampered by the inherent random nature and the multiplicity of variables. A stochastic simulation model has been developed to determine the active grain density on the media surface which is in contact with

Rajendra K. Jain; V. K. Jain

2004-01-01

120

Passive and Active Flow Control by Swimming Fishes and Mammals  

E-print Network

velocimetry, flukes, biomechanics, hydrodynamics, biomimetic Abstract What mechanisms of flow control do@oeb.harvard.edu Annu. Rev. Fluid Mech. 2006. 38:193­224 The Annual Review of Fluid Mechanics is online at fluid the body and appendages both passively and actively. Passive mechanisms rely on structural

Fish, Frank

121

Pulsed-flow air classification for waste-to-energy  

Microsoft Academic Search

The development and testing of the concept of pulsed-flow air classification for waste-to-energy production are discussed. Air classifiers, a potentially valuable unit operation in waste-to-energy production facilities, currently do not meet expectations. Standard designs generally lose large amounts of combustible material as well as produce a fuel that is high in metal and glass contaminants. Pulsed-flow classification is presented as

Richard Ian Stessel; J. Jeffrey Peirce

1983-01-01

122

Multitemporal LIDAR acquisition of active lava flows at Mt. Etna  

NASA Astrophysics Data System (ADS)

Application of airborne-based light detection and ranging (LIDAR) technology in volcanology has spread rapidly over the past few years, being extremely useful for generation of high-resolution digital elevation models (DEM) and mapping eruption products. The raw output of a LIDAR survey consists of the 3D positions of a cloud of points, along with their backscatter intensity signal. The intensity signal must be normalized to account for the uneven geometric factors affecting its values such as the varying distance between the sensor and the reflecting surface during the airborne-based survey. The derived corrected intensity maps are useful for the identification and mapping of different lava flows since intensity values are a function of the age of lava emplacement. Lava flow mapping can also be obtained by the analysis of topographic changes when pre- and post-emplacement topographies are available. At Mt. Etna we carried out airborne LIDAR surveys in 2004, 2005, 2006, 2007 and 2010. The 2004 and 2006 LIDAR acquisitions were performed during ongoing effusive activities allowing precise measurements of the morphological features of active lava channels. The 2006 survey, in particular, was carried out on November 17-18 on the upper slopes of the Valle del Bove (East flank of Mt. Etna) where a compound lava flow field was emplacing. The survey flight was specifically planned as a series of crossings (about 15' apart to cover a period of 2 hours each day) over the flow field to acquire a number of strips (one at each crossing) of the active lava channels. From each strip, a high resolution DEM has been independently derived obtaining a time series of DEMs representing the evolution of this complex lava flow field. Such short period time-series of LIDAR-derived DEMs are very useful to extract detailed information about the dynamics of lava movement, emplacement processes occurring across active lava flow field, and the volumes involved. In analyzing LIDAR data, special effort must be put into three crucial technical aspects: the correction for systematic errors in raw LIDAR data, the DEM-to-DEM co-registration, and the statistical quantification of residual errors. Differences between the different DEMs derived by LIDAR time-series show that the emplacement of flow units is characterized by pulses of lava moving along channel. Lava fluxes have been calculated for several flow units. Volumes and velocities of different pulses are uneven, highlighting a complex non linear emplacement of compound lava flows.

Favalli, M.; Fornaciai, A.; Mazzarini, F.; Tarquini, S.

2012-12-01

123

Measurement of energy distribution in flowing hydrogen microwave plasmas  

NASA Technical Reports Server (NTRS)

An electrothermal propulsion concept utilizing a microwave plasma system as the mechanism to convert electromagnetic energy into kinetic energy of a flowing gas is investigated. A calorimetry system enclosing a microwave plasma system has been developed to accurately measure the energy inputs and outputs of the microwave plasma system. The rate of energy transferred to the gas can be determined to within + or - 1.8 W from an energy balance around the microwave plasma system. The percentage of the power absorbed by the microwave plasma system transferred to the hydrogen gas as it flows through the system is found to increase with the increasing flow rate, to decrease with the increasing pressure, and to be independent of the absorbed power. An upper bound for the hydrogen gas temperature is estimated from the energy content, heat capacity, and flow rate of the gas stream. A lower bound for an overall heat-transfer coefficient is then calculated, characterizing the energy loss from the hydrogen gas stream to the air cooling of the plasma discharge tube wall. The heat-transfer coefficient is found to increase with the increasing flow rate and pressure and to be independent of the absorbed power. This result indicates that a convective-type mechanism is responsible for the energy transfer.

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

1985-01-01

124

Stocks, Flows, and Prospects of Energy  

E-print Network

of knowledge on the boundaries that will impact a sustainable energy system. A more integrated view of energy for in analyses currently available. From our point of view, there is a pressing lack of knowledge with regard to ensure the well-being of current and future generations. Very roughly, sustainability of the energy

125

ACTIVITY BUDGETS, ENERGY EXPENDITURES, AND  

Microsoft Academic Search

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 18.1 kcal\\/day, whereas the adult females expended 265.3 -+ 28.3 and 294.6 34.5 kcal\\/ day. The

FERRUGINOUS HAWKS; JAMES S. WAKELEY

126

Stochastic dynamics of active swimmers in linear flows  

E-print Network

Most classical work on the hydrodynamics of low-Reynolds-number swimming addresses deterministic locomotion in quiescent environments. Thermal fluctuations in fluids are known to lead to a Brownian loss of the swimming direction. As most cells or synthetic swimmers are immersed in external flows, we consider theoretically in this paper the stochastic dynamics of a model active particle (a self-propelled sphere) in a steady general linear flow. The stochasticity arises both from translational diffusion in physical space, and from a combination of rotary diffusion and run-and-tumble dynamics in orientation space. We begin by deriving a general formulation for all components of the long-time mean square displacement tensor for a swimmer with a time-dependent swimming velocity and whose orientation decorrelates due to rotary diffusion alone. This general framework is applied to obtain the convectively enhanced mean-squared displacements of a steadily-swimming particle in three canonical linear flows (extension, simple shear, and solid-body rotation). We then show how to extend our results to the case where the swimmer orientation also decorrelates on account of run-and-tumble dynamics. Self-propulsion in general leads to the same long-time temporal scalings as for passive particles in linear flows but with increased coefficients. In the particular case of solid-body rotation, the effective long-time diffusion is the same as that in a quiescent fluid, and we clarify the lack of flow-dependence by briefly examining the dynamics in elliptic linear flows. By comparing the new active terms with those obtained for passive particles we see that swimming can lead to an enhancement of the mean-square displacements by orders of magnitude, and could be relevant for biological organisms or synthetic swimming devices in fluctuating environmental or biological flows.

Mario Sandoval; Navaneeth K. M.; Ganesh Subramanian; Eric Lauga

2014-06-17

127

Stochastic dynamics of active swimmers in linear flows  

NASA Astrophysics Data System (ADS)

Most classical work on the hydrodynamics of low-Reynolds-number swimming addresses deterministic locomotion in quiescent environments. Thermal fluctuations in fluids are known to lead to a Brownian loss of the swimming direction. As most cells or synthetic swimmers are immersed in external flows, we consider theoretically in this paper the stochastic dynamics of a model active particle (a self-propelled sphere) in a steady general linear flow. The stochasticity arises both from translational diffusion in physical space, and from a combination of rotary diffusion and run-and-tumble dynamics in orientation space. We begin by deriving a general formulation for all components of the long-time mean square displacement tensor for a swimmer with a time-dependent swimming velocity and whose orientation decorrelates due to rotary diffusion alone. This general framework is applied to obtain the convectively enhanced mean-squared displacements of a steadily-swimming particle in three canonical linear flows (extension, simple shear, and solid-body rotation). We then show how to extend our results to the case where the swimmer orientation also decorrelates on account of run-and-tumble dynamics. Self-propulsion in general leads to the same long-time temporal scalings as for passive particles in linear flows but with increased coefficients. In the particular case of solid-body rotation, the effective long-time diffusion is the same as that in a quiescent fluid, and we clarify the lack of flow-dependence by briefly examining the dynamics in elliptic linear flows. By comparing the new active terms with those obtained for passive particles we see that swimming can lead to an enhancement of the mean-square displacements by orders of magnitude, and could be relevant for biological organisms or synthetic swimming devices in fluctuating environmental or biological flows.

Sandoval, Mario; Marath, Navaneeth K.; Subramanian, Ganesh; Lauga, Eric

2014-03-01

128

Numerical modeling of energy related flows. Final report  

SciTech Connect

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)

Berger, B.S.

1984-12-05

129

Transonic flow control by means of local energy deposition  

NASA Astrophysics Data System (ADS)

Experimental data for the feasibility of transonic flow control by means of energy deposition are generalized. Energy supplied to the immediate vicinity of a body in stream before a compression shock is found to result in the nonlinear interaction of introduced disturbances with the shock and the surface in zones extended along the surface. A new, explosive gasdynamic mechanism behind the shift of the compression shock is discovered. It is shown that the nonlinear character of the interaction may considerably decrease the wave resistance of, e.g., transonic airfoils. It is found that energy supply from without stabilizes a transonic flow about an airfoilthe effect similar to the Khristianovich stabilization effect. The dependence of the energy deposition optimal frequency on the energy source parameters and Mach number of the incoming flow at which the resistance drops to the greatest extent is obtained. The influence of the real thermodynamic properties and viscosity of air is studied.

Aul'Chenko, S. M.; Zamuraev, V. P.; Kalinina, A. P.

2011-11-01

130

A new energy transfer model for turbulent free shear flow  

NASA Technical Reports Server (NTRS)

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.

Liou, William W.-W.

1992-01-01

131

Dynamics of a deformable active particle under shear flow.  

PubMed

The motion of a deformable active particle in linear shear flow is explored theoretically. Based on symmetry considerations, we propose coupled nonlinear dynamical equations for the particle position, velocity, deformation, and rotation. In our model, both, passive rotations induced by the shear flow as well as active spinning motions, are taken into account. Our equations reduce to known models in the two limits of vanishing shear flow and vanishing particle deformability. For varied shear rate and particle propulsion speed, we solve the equations numerically in two spatial dimensions and obtain a manifold of different dynamical modes including active straight motion, periodic motions, motions on undulated cycloids, winding motions, as well as quasi-periodic and chaotic motions induced at high shear rates. The types of motion are distinguished by different characteristics in the real-space trajectories and in the dynamical behavior of the particle orientation and its deformation. Our predictions can be verified in experiments on self-propelled droplets exposed to a linear shear flow. PMID:24050364

Tarama, Mitsusuke; Menzel, Andreas M; ten Hagen, Borge; Wittkowski, Raphael; Ohta, Takao; Lwen, Hartmut

2013-09-14

132

Low-Speed Active Flow Control Laboratory Developed  

NASA Technical Reports Server (NTRS)

The future of aviation propulsion systems is increasingly focused on the application of control technologies to significantly enhance the performance of a new generation of air vehicles. Active flow control refers to a set of technologies that manipulate the flow of air and combustion gases deep within the confines of an engine to dynamically alter its performance during flight. By employing active flow control, designers can create engines that are significantly lighter, are more fuel efficient, and produce lower emissions. In addition, the operating range of an engine can be extended, yielding safer transportation systems. The realization of these future propulsion systems requires the collaborative development of many base technologies to achieve intelligent, embedded control at the engine locations where it will be most effective. NASA Glenn Research Center s Controls and Dynamics Technology Branch has developed a state-of-the-art low-speed Active Flow Control Laboratory in which emerging technologies can be integrated and explored in a flexible, low-cost environment. The facility allows the most promising developments to be prescreened and optimized before being tested on higher fidelity platforms, thereby reducing the cost of experimentation and improving research effectiveness.

Culley, Dennis E.; Bright, Michelle M.

2005-01-01

133

Finite Elemente Large Eddy Simulation of Flows Past Bluff Bodies with Active Flow Control  

NASA Astrophysics Data System (ADS)

A semi-implicit fractional step finite element large eddy simulation (LES) method for unstructured grids has been developed. The turbulence models implemented into the code are the constant and dynamic coefficient Smagorinsky models as well as the stress similarity model of Liu et al. The technique was applied to analyzing the effects of active flow control by massless oscillatory blowing from a slot. Especially flows past bluff bodies (e.g. circular cylinder; download on a tiltrotor wing) were investigated. Numerical optimization was used to find optimum parameters such as slot location, slot angle, frequency, etc. The numerical results are compared with experimental PIV (Particle Image Velocimetry) and pressure measurements.

Kjellgren, Per; Taubert, Lutz; Wygnanski, I. J.

2001-11-01

134

Stochastic dynamics of active swimmers in linear flows  

E-print Network

Most classical work on the hydrodynamics of low-Reynolds-number swimming addresses deterministic locomotion in quiescent environments. Thermal fluctuations in fluids are known to lead to a Brownian loss of the swimming direction. As most cells or synthetic swimmers are immersed in external flows, we consider theoretically in this paper the stochastic dynamics of a model active particle (a self-propelled sphere) in a steady general linear flow. The stochasticity arises both from translational diffusion in physical space, and from a combination of rotary diffusion and run-and-tumble dynamics in orientation space. We begin by deriving a general formulation for all components of the long-time mean square displacement tensor for a swimmer with a time-dependent swimming velocity and whose orientation decorrelates due to rotary diffusion alone. This general framework is applied to obtain the convectively enhanced mean-squared displacements of a steadily-swimming particle in three canonical linear flows (extension, s...

Sandoval, Mario; Subramanian, Ganesh; Lauga, Eric

2014-01-01

135

Flow of energy in an urban society  

SciTech Connect

This article attempts to assess how a modern urban area consumes energy either directly or indirectly. One of the most important outcomes of this study is a complete picture of an urban energy system, i.e., the entire source-service fuel cycle involving the sources, transportation modes, distribution channels, and consumption pattern of all the energy carriers for a period of 10 years (980--90) for Bangalore, a city in southern India. The study also led to a detailed end-use analysis of energy carriers, and a source-service matrix is prepared for Bangalore. The impact of energy consumption on forests, environment, transportation, and the economy as a whole is discussed here.

Reddy, B.S. [Indira Gandhi Inst. of Development Research, Bombay (India)

1997-04-01

136

Active Flow Control on Bidirectional Rotors for Tidal MHK Applications  

SciTech Connect

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.

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

2013-08-22

137

Fluid flow and heat convection studies for actively cooled airframes  

NASA Technical Reports Server (NTRS)

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.

Mills, A. F.

1992-01-01

138

Energy momentum flows for the massive vector field  

E-print Network

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.

George Horton; Chris Dewdney

2006-09-26

139

Hydrogen-Bromine Flow Battery: Hydrogen Bromine Flow Batteries for Grid Scale Energy Storage  

SciTech Connect

GRIDS Project: LBNL is designing a flow battery for grid storage that relies on a hydrogen-bromine chemistry which could be more efficient, last longer and cost less than todays lead-acid batteries. Flow batteries are fundamentally different from traditional lead-acid batteries because the chemical reactants that provide their energy are stored in external tanks instead of inside the battery. A flow battery can provide more energy because all that is required to increase its storage capacity is to increase the size of the external tanks. The hydrogen-bromine reactants used by LBNL in its flow battery are inexpensive, long lasting, and provide power quickly. The cost of the design could be well below $100 per kilowatt hour, which would rival conventional grid-scale battery technologies.

None

2010-10-01

140

Forward Jets and Energy Flow in Hadronic Collisions  

E-print Network

We observe that at the Large Hadron Collider, using forward + central detectors, it becomes possible for the first time to carry out calorimetric measurements of the transverse energy flow due to "minijets" accompanying production of two jets separated by a large rapidity interval. We present parton-shower calculations of energy flow observables in a high-energy factorized Monte Carlo framework, designed to take into account QCD logarithmic corrections both in the large rapidity interval and in the hard transverse momentum. Considering events with a forward and a central jet, we examine the energy flow in the interjet region and in the region away from the jets. We discuss the role of these observables to analyze multiple parton collision effects.

M. Deak; F. Hautmann; H. Jung; K. Kutak

2011-12-29

141

Benefits of Active Flow Control for Wind Turbine Blades  

NASA Astrophysics Data System (ADS)

In this talk, the blade element momentum model is used to design a wind turbine and examine the benefit of active flow control. The results suggest that either the overall operational range of the wind turbine could be effectively enlarged by 80% with the same rated power output or the rated output power could be increased by 20% while maintaining the same level of operational range when the control is on. The optimal location for the actuator is found to be on the outboard of the blade beyond half of the radius. In light of these encouraging results and based on our earlier NACA 4412 flow control studies, a characteristic airfoil (e.g. DU-96-W-180) is being tested in a new anechoic wind tunnel facility at Syracuse University to determine the airfoil lift and drag characteristics with appropriate flow control while exposed to large scale flow unsteadiness. In addition, the effects of flow controllers on the noise spectrum of the wind turbine will be also assessed and measured in the anechoic chamber.

Wang, Guannan; Elhadidi, Basman; Walczak, Jakub; Glauser, Mark; Higuchi, Hiroshi

2010-11-01

142

Vortical ciliary flows actively enhance mass transport in reef corals.  

PubMed

The exchange of nutrients and dissolved gasses between corals and their environment is a critical determinant of the growth of coral colonies and the productivity of coral reefs. To date, this exchange has been assumed to be limited by molecular diffusion through an unstirred boundary layer extending 1-2 mm from the coral surface, with corals relying solely on external flow to overcome this limitation. Here, we present direct microscopic evidence that, instead, corals can actively enhance mass transport through strong vortical flows driven by motile epidermal cilia covering their entire surface. Ciliary beating produces quasi-steady arrays of counterrotating vortices that vigorously stir a layer of water extending up to 2 mm from the coral surface. We show that, under low ambient flow velocities, these vortices, rather than molecular diffusion, control the exchange of nutrients and oxygen between the coral and its environment, enhancing mass transfer rates by up to 400%. This ability of corals to stir their boundary layer changes the way that we perceive the microenvironment of coral surfaces, revealing an active mechanism complementing the passive enhancement of transport by ambient flow. These findings extend our understanding of mass transport processes in reef corals and may shed new light on the evolutionary success of corals and coral reefs. PMID:25192936

Shapiro, Orr H; Fernandez, Vicente I; Garren, Melissa; Guasto, Jeffrey S; Debaillon-Vesque, Franois P; Kramarsky-Winter, Esti; Vardi, Assaf; Stocker, Roman

2014-09-16

143

Energy Activities for the Primary Classroom. Revised.  

ERIC Educational Resources Information Center

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

Tierney, Blue, Comp.

144

Mechanical energy flow models of rods and beams  

NASA Technical Reports Server (NTRS)

It has been proposed that the flow of mechanical energy through a structural/acoustic system may be modeled in a manner similar to that of flow of thermal energy/in a heat conduction problem. If this hypothesis is true, it would result in relatively efficient numerical models of structure-borne energy in large built-up structures. Fewer parameters are required to approximate the energy solution than are required to model the characteristic wave behavior of structural vibration by using traditional displacement formulations. The energy flow hypothesis is tested in this investigation for both longitudinal vibration in rods and transverse flexural vibrations of beams. The rod is shown to behave approximately according to the thermal energy flow analogy. However, the beam solutions behave significantly differently than predicted by the thermal analogy unless locally-space-averaged energy and power are considered. Several techniques for coupling dissimilar rods and beams are also discussed. Illustrations of the solution accuracy of the methods are included.

Wohlever, J. C.; Bernhard, R. J.

1992-01-01

145

Conformal curvature flows: From phase transitions to active vision  

Microsoft Academic Search

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

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

1996-01-01

146

Conformal Curvature Flows: From Phase Transitions to Active Vision  

Microsoft Academic Search

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

Satyanad Kichenassamy; Arun Kumar

1995-01-01

147

CORRELATED NEURONAL ACTIVITY AND THE FLOW OF NEURAL INFORMATION  

PubMed Central

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 of information in the brain. PMID:11483997

Salinas, Emilio; Sejnowski, Terrence J.

2010-01-01

148

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

SciTech Connect

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 Grids devices clamp onto existing transmission lines and control the flow of power withinmuch 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 grids inability to effectively store intermittent energy from renewables for later use.

None

2012-04-24

149

An artificial energy method for calculating flows with shocks  

NASA Technical Reports Server (NTRS)

The artificial-viscosity method, first proposed by von Neumann and Richtmyer, introduces an artificial viscous pressure term in regions of compression such that an increase in entropy occurs in shock transition zones. The paper describes how dissipative flows can be induced by reducing the total energy available for adiabatic processes in shock zones. A class of inviscid fluid flows, called semiflows, is described in which the flows exhibit thermodynamic differences. Induced dissipative flows modify the pressure in regions of compression in a manner analogous to the artificial-viscosity method and for a gas, the effect is equivalent to suitably modifying the gas constant in the equation of state. By employing MacCormack's method and the usual non-adiabatic equations, numerical solutions of a Riemann problem are compared with the modified artificial energy method, showing that the dissipation effect predicted by the analytical formulation is reflected in the numerical method as well.

Rose, M. E.

1980-01-01

150

Continuous flow, evaporative-type thermal energy recovery apparatus and method for thermal energy recovery  

Microsoft Academic Search

A continuous flow, evaporative-type thermal energy recovery apparatus comprises an evaporator unit to which are supplied continuous pressurized flows of hot water and air, and in which a portion of the hot water is evaporated into the air, preferably to completely saturate the air with moisture. Connected to receive the resulting flow of pressurized, water saturated air from the evaporator

Bissell

1978-01-01

151

An integral turbulent kinetic energy analysis of free shear flows  

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

152

Vorticity of Subsurface Flows of Emerging and Decaying Active Regions  

NASA Astrophysics Data System (ADS)

We study the temporal variation of the vorticity of subsurface flows of 828 active regions and 977 quiet regions. The vorticity of these flows is derived from measured subsurface velocities. The horizontal flows are determined by analyzing high-resolution Global Oscillation Network Group Doppler data with ring-diagram analysis covering a range of depths from the surface to about 16 Mm. The vertical velocity component is derived from the divergence of the measured horizontal flows using mass conservation. We determine the change in unsigned magnetic flux density during the disk passage of each active region using Michelson Doppler Imager (MDI) magnetograms binned to the ring-diagram grid with centers spaced by 7.5 ranging 52.5 in latitude and central meridian distance with an effective diameter of 15 after apodization. We then sort the data by their flux change from decaying to emerging flux and divide the data into five subsets of equal size. We find that the vorticity of subsurface flows increases during flux emergence and decreases when active regions decay. For flux emergence, the absolute values of the zonal and meridional vorticity components show the most coherent variation with activity, while for flux decrease the strongest signature is in the absolute values of the meridional and vertical vorticity components. The temporal variation of the enstrophy (residual vorticity squared) is thus a good indicator for either flux increase or decrease. There are some indications that the increase in vorticity during flux emergence happens about a day later at depths below about 8 Mm compared to layers shallower than about 4 Mm. This timing difference might imply that the vorticity signal analyzed here is caused by the interaction between magnetic flux and turbulent flows near the solar surface. There are also hints that the vorticity decrease during flux decay begins about a day earlier at layers deeper than about 8 Mm compared to shallower ones. However, the timing difference between the change at different depths is comparable to the time step of the analysis.

Komm, R.; Howe, R.; Hill, F.

2012-04-01

153

Use DCF to save energy. [Discounted Cash Flow (DCF) program  

SciTech Connect

The Discounted Cash Flow (DCF) program is written for the TI-59 programmable calculator, and a profitability analysis can help the process engineer decide among various alternatives in an energy conservation project. The objective of the analysis is to determine the following parameters: discounted cash flow rate of return (also called earning power), present value profit (at any specified cost of capital), present value profit as a percent of the capital investment, and the payback period (undiscounted).

Doane, R.C.

1982-07-01

154

Photon field and energy flow lines behind a circular disc  

NASA Astrophysics Data System (ADS)

In order to evaluate electromagnetic energy flow (EME) lines behind a circular disc illuminated by monochromatic laser light, the Rayleigh–Sommerfeld integral is transformed to a simpler form. EME flow lines, interpreted as photon trajectories, explain the change of the intensity pattern with the distance from a circular disc very well, including the Poisson–Arago spot in the center. Possible applications of these results on the study of Poisson–Arago spot experiments with matter beams, are indicated and explained.

Arsenovi?, D.; Dimic, D.; Boi?, M.

2014-09-01

155

Active Motion in Systems with Energy Supply  

Microsoft Academic Search

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

Werner Ebeling; Frank Schweitzer

2001-01-01

156

Approximations to the Distributed Activation Energy Model  

E-print Network

Approximations to the Distributed Activation Energy Model for Pyrolysis C.P. Please, 1 M.J. Mc, then resubmitted after minor revisions in September 2002. Abstract The Distributed Activation Energy Model (DAEM effective method for estimating kinetic parameters and the distribution of activation energies. Comparison

McGuinness, Mark

157

Influence of NO-Containing Gas Flow on Various Parameters of Energy Metabolism in Erythrocytes.  

PubMed

We studied the influence of NO-containing gas phase on some parameters of energy metabolism in human erythrocytes. Whole blood samples were aerated with gas flows from the Plazon instrument (NO concentrations 800 and 80 ppm) and from the experimental generator (75 ppm). Activity of lactate dehydrogenase in direct and reverse reactions, lactate level, and a number of derived coefficients were estimated. Treatment of blood with 800 ppm NO inhibited erythrocyte energy metabolism, and its 10-fold dilution attenuated the effect. The use of ROS-free gas flow containing 75 ppm of NO promoted optimization of the process under investigation. PMID:25403392

Martusevich, A K; Solov'yova, A G; Peretyagin, S P; Karelin, V I; Selemir, V D

2014-11-01

158

U.S. energy flow - 1993  

SciTech Connect

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.

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

1994-10-01

159

Ambient wind energy harvesting using cross-flow fluttering  

NASA Astrophysics Data System (ADS)

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. We fabricated prototypes using flexible piezoelectric materials as stalks and polymer film as leaves. A series of experiments demonstrated a peak output power of approximately 600 ?W and maximum power density of approximately 2 mW/cm3 from a single leaf.

Li, Shuguang; Yuan, Jianping; Lipson, Hod

2011-01-01

160

FUNDAMENTAL EXPERIMENTAL AND NUMERICAL INVESTIGATION OF ACTIVE CONTROL OF 3-D FLOWS  

E-print Network

FUNDAMENTAL EXPERIMENTAL AND NUMERICAL INVESTIGATION OF ACTIVE CONTROL OF 3-D FLOWS Sponsor: Air, Dan Finigan PROJECT DESCRIPTION The current research is focused on Flow Control over finite wings. The effect of active flow control, via arrays of synthetic jet actuators, on the flow field around a finite

Salama, Khaled

161

Flow of Energy and Matter: Photosynthesis  

NSDL National Science Digital Library

In this chapter, the authors explore the misconception that carbon from carbon dioxide is the source of a plant's mass. They also look at other common, research-identified misconceptions that make it difficult for students to understand photosynthesis and to connect the photosynthetic processes in a plant cell to the plant and its surroundings. They focus on photosynthesis as a mechanism for harnessing energy and generating organic carbon from atmospheric carbon. In addition, they briefly discuss what happens to that carbon in the plant once photosynthesis is complete and gas exchange in plants during respiration. This free selection includes the Table of Contents, Introduction, and Index.

Tweed, Susan K.

2009-05-01

162

Energy flow in an arctic aquatic ecosystem  

SciTech Connect

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.

Schell, D.M.

1983-12-31

163

Energy flow in an arctic aquatic ecosystem  

SciTech Connect

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.

Schell, D.M.

1983-01-01

164

Biphasic flow in a chemically active porous medium  

E-print Network

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 fo...

Darmon, Alexandre; Salez, Thomas; Dauchot, Olivier

2014-01-01

165

Spontaneous flow states in active nematics: a unified picture  

E-print Network

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.

S. A. Edwards; J. M. Yeomans

2008-11-21

166

Biphasic flow in a chemically active porous medium  

E-print Network

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.

Alexandre Darmon; Michael Benzaquen; Thomas Salez; Olivier Dauchot

2014-09-08

167

Energy Storage. Teachers Guide. Science Activities in Energy.  

ERIC Educational Resources Information Center

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

Jacobs, Mary Lynn, Ed.

168

Analysis of energy flow during playground surface impacts.  

PubMed

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

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

2013-10-01

169

Active flow control for a blunt trailing edge profiled body  

NASA Astrophysics Data System (ADS)

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

Naghib Lahouti, Arash

170

Fluid flow systems analysis to save energy  

SciTech Connect

Industrial processes use rotating equipment (e.g.; pump, fan, blower, centrifugal compressor, positive displacement compressor) and pipe (or duct) to move fluid from point A to B, with many processes using electric motors as the prime mover. Most of the systems in the industry are over-designed to meet a peak load demand which might occur over a small fraction of the time or to satisfy a higher pressure demanded by a much smaller user in the same process. The system over-design will result in a selection of larger but inefficient rotating equipment and electric motor system. A careful life cycle cost and economic evaluation must be undertaken to ensure that the process audit, reengineering and equipment selections are not impacting the industrial process goals, but result in a least optimal cost over the life of the project. The paper will define, discuss, and present various process systems in chemical, hydrocarbon and pulp and paper industries. It will discuss the interactive impact of the changes in the mechanical system configuration and the changes in the process variables to better redesign the system and reduce the cost of operation. it will also present a check list of energy conservation measures (ECM) or opportunities. Such ECMs will be related to hydraulics, system components, process modifications, and system efficiency. Two or three case studies will be presented focusing on various conservation measures that improve electrical operating efficiency of a distillation column system. An incremental cost and payback analysis will be presented to assist the investment in process optimization and energy savings' measures.

Parekh, P.S.

1999-07-01

171

Snapshot of Active Flow Control Research at NASA Langley  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

172

Continuous thermal energy delivery from a periodically active energy source  

Microsoft Academic Search

An apparatus is described for continuous delivery of relatively uniform predetermined thermal energy from a cyclically active thermal energy source having an ON period substantially exceeding an OFF period in duration to an energy utilization sector of a closed working fluid conduit loop additionally comprising an energy supply sector, the energy supply sector comprising: working fluid conduit means for containment

Kardas

1988-01-01

173

Zero-Energy Rotating Accretion Flows near a Black Hole  

NASA Astrophysics Data System (ADS)

We characterize the nature of thin, axisymmetric, inviscid accretion flows of cold adiabatic gas with zero specific energy in the vicinity of a black hole by the specific angular momentum. Using two-dimensional hydrodynamic simulations in cylindrical geometry, we present various regimes in which the accretion flows behave distinctly differently. When the flow has a small angular momentum (? <~ ?b), most of the material is accreted into the black hole, forming a quasi-spherical flow or a simple disklike structure around it. When the flow has a large angular momentum (typically, larger than the marginally bound value, ? >~ ?mb), almost no accretion into the black hole occurs. Instead, the flow produces a stable standing shock with one or more vortices behind it and is deflected away at the shock as a conical, outgoing wind of higher entropy. If the flow has an angular momentum somewhat smaller than ?mb (?u <~ ? <~ ?mb), a fraction (typically 5%-10%) of the incoming material is accreted into the black hole, but the flow structure formed is similar to that for ? >~ ?mb. Some of the deflected material is accreted back into the black hole while the rest is blown away as an outgoing wind. These two cases with ? >~ ?u correspond those studied in the previous works by Molteni, Lanzafame, & Chakrabarti and Ryu et al. However, the flow with angular momentum close to the marginally stable value (?ms) is found to be unstable. More specifically, if ?b <~ ? ~ ?ms <~ ?u, the flow displays a distinct periodicity in the sense that the inner part of the disk is built and destroyed regularly. The period is roughly equal to (4-6) 103Rg/c, depending on the angular momentum of the flow. In this case, the internal energy of the flow around the black hole becomes maximum when the structure with the accretion shock and vortices is fully developed. But the mass accretion rate into the black hole reaches a maximum value when the structure collapses. Averaged over periods, more than half the incoming material is accreted into the black hole. We suggest the physical origin of these separate regimes from a global perspective. Then we discuss the possible relevance of the instability work to quasi-periodic oscillations.

Ryu, Dongsu; Chakrabarti, Sandip K.; Molteni, Diego

1997-01-01

174

Endocannabinoids Control Platelet Activation and Limit Aggregate Formation under Flow  

PubMed Central

Background The endocannabinoid system has previously been implicated in the regulation of neurons and inflammatory cells. Additionally, it has been reported that endocannabinoid receptors are present on circulating platelets, but there has been conflicting evidence on their contribution to platelet function. Objectives Our aim was to examine the role of endocannabinoids in platelet function in vitro and in vivo. Methods and Results We studied the effects of the well-characterized endogenous endocannabinoid anandamide on platelet aggregation in suspension, ?-granule release, calcium mobilization, Syk phosphorylation, as well as platelet spreading and aggregate formation under flow. Anandamide inhibits platelet aggregation and ?-granule release by collagen, collagen-derived peptide CRP-XL, ADP, arachidonic acid and thromboxane A2 analogue U46619. However, activation via thrombin receptor PAR-1 stays largely unaffected. Calcium mobilization is significantly impaired when platelets are stimulated with collagen or CRP-XL, but remains normal in the presence of the other agonists. In line with this finding, we found that anandamide prevents collagen-induced Syk phosphorylation. Furthermore, anandamide-treated platelets exhibit reduced spreading on immobilized fibrinogen, have a decreased capacity for binding fibrinogen in solution and show perturbed platelet aggregate formation under flow over collagen. Finally, we investigated the influence of Cannabis sativa consumption by human volunteers on platelet activation. Similar to our in vitro findings with anandamide, ex vivo collagen-induced platelet aggregation and aggregate formation on immobilized collagen under flow were impaired in whole blood of donors that had consumed Cannabis sativa. Conclusions Endocannabinoid receptor agonists reduce platelet activation and aggregate formation both in vitro and ex vivo after Cannabis sativa consumption. Further elucidation of this novel regulatory mechanism for platelet function may prove beneficial in the search for new antithrombotic therapies. PMID:25264625

De Angelis, Valentina; Koekman, Arnold C.; Weeterings, Cees; Roest, Mark; de Groot, Philip G.; Herczenik, Eszter; Maas, Coen

2014-01-01

175

Dark energy and the quietness of the local Hubble flow  

NASA Astrophysics Data System (ADS)

The linearity and quietness of the local (<10 Mpc) Hubble flow (LHF) in view of the very clumpy local universe is a long standing puzzle in standard and in open CDM (cold dark matter) cosmogony. The question addressed in this paper is whether the antigravity component of the recently discovered dark energy can cool the velocity flow enough to provide a solution to this puzzle. We calculate the growth of matter fluctuations in a flat universe containing a fraction ?X(t0) of dark energy obeying the time independent equation of state pX=w?X. We find that dark energy can indeed cool the LHF. However the dark energy parameter values required to make the predicted velocity dispersion consistent with the observed value vrms~=40 km/s have been ruled out by other observational tests constraining the dark energy parameters w and ?X. Therefore despite the claims of recent qualitative studies, dark energy with time independent equation of state cannot by itself explain the quietness and linearity of the local Hubble flow.

Axenides, M.; Perivolaropoulos, L.

2002-06-01

176

Groundwater Flow Demonstration Model Activities for Grades 6-12  

NSDL National Science Digital Library

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).

Farrell-Poe, Kitt

177

Power flow analysis for amplifier design and energy harvesting  

E-print Network

regenerative braking concept. As a result, some part of the external energy to the system was absorbed which or both of the flow states (velocity and current). This regenerative control strategy also affects the closed loop dynamics. The regenerative control applied to a voice-coil actuator results in a closed loop

Lindner, Douglas K.

178

Energy Flow and Rapidity Gaps Between Jets in Photoproduction  

E-print Network

Energy Flow and Rapidity Gaps Between Jets in Photoproduction Angela Wyatt October 2001 Particle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.3.1 The Liquid Argon Calorimeter . . . . . . . . . . . . . . . . . . 14 2.3.2 The Spa Evolution Mechanism . . . . . . . . . . . . . . . 37 3.3.2 The BFKL Evolution Mechanism

179

U.S. energy flow -- 1994  

SciTech Connect

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, this understates the increase of the total amount of electricity used in the nation because the amount of electricity used ``in-house`` by a growing number of self-generators is unrecorded. Imports of both fossil fuels and electricity increased. About half of the total oil consumed was imported, with Saudi Arabia being the principal supplier. Domestic oil production continued to decline; however, the sharp decline in Alaskan production was slowed. The increase in the demand for natural gas was met by both a modest increase in domestic production and imports from Canada, which comprised 10% of supply. The residential/commercial sector is the largest single consumer of natural gas; however, use by electric generators has increased annually for the past decade. The regulated utilities increased their consumption 11% in 1994. The year was noteworthy for the US nuclear power industry. Work was halted on the last nuclear power plant under construction in the country. Because of the retirement of aged and poorly performing nuclear plants and because of improved efficiencies, the capacity factor for the remaining 109 operable plants reached a record 74%.

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

1995-12-01

180

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

SciTech Connect

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.

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

181

Cellular Links between Neuronal Activity and Energy Homeostasis  

PubMed Central

Neuronal activity, astrocytic responses to this activity, and energy homeostasis are linked together during baseline, conscious conditions, and short-term rapid activation (as occurs with sensory or motor function). Nervous system energy homeostasis also varies during long-term physiological conditions (i.e., development and aging) and with adaptation to pathological conditions, such as ischemia or low glucose. Neuronal activation requires increased metabolism (i.e., ATP generation) which leads initially to substrate depletion, induction of a variety of signals for enhanced astrocytic function, and increased local blood flow and substrate delivery. Energy generation (particularly in mitochondria) and use during ATP hydrolysis also lead to considerable heat generation. The local increases in blood flow noted following neuronal activation can both enhance local substrate delivery but also provides a heat sink to help cool the brain and removal of waste by-products. In this review we highlight the interactions between short-term neuronal activity and energy metabolism with an emphasis on signals and factors regulating astrocyte function and substrate supply. PMID:22470340

Shetty, Pavan K.; Galeffi, Francesca; Turner, Dennis A.

2012-01-01

182

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

ERIC Educational Resources Information Center

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

Theiss, Nancy Stearns, Ed.; And Others

183

Energy Conservation Activity Packet, Grade 6.  

ERIC Educational Resources Information Center

This activity packet for grade 6 is one of a series 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 grade six. The packet is divided into two parts and provides the teacher with background information, concepts and

Bakke, Ruth

184

Observations of photospheric magnetic fields and shear flows in flaring active regions  

NASA Technical Reports Server (NTRS)

Horizontal flows in the photosphere and subsurface convection zone move the footpoints of coronal magnetic field lines. Magnetic energy to power flares can be stored in the corona if the flows drive the fields far from the potential configuration. Videodisk movies were shown with 0.5 to 1 arcsecond resolution of the following simultaneous observations: green continuum, longitudinal magnetogram, Fe I 5576 A line center (mid-photosphere), H alpha wings, and H alpha line center. The movies show a 90 x 90 arcsecond field of view of an active region at S29, W11. When viewed at speeds of a few thousand times real-time, the photospheric movies clearly show the active region fields being distorted by a remarkable combination of systematic flows and small eruptions of new flux. Magnetic bipoles are emerging over a large area, and the polarities are systematically flowing apart. The horizontal flows were mapped in detail from the continuum movies, and these may be used to predict the future evolution of the region. The horizontal flows are not discernable in H alpha. The H alpha movies strongly suggest reconnection processes in the fibrils joining opposite polarities. When viewed in combination with the magnetic movies, the cause for this evolution is apparent: opposite polarity fields collide and partially cancel, and the fibrils reconnect above the surface. This type of reconnection, driven by subphotospheric flows, complicates the chromospheric and coronal fields, causing visible braiding and twisting of the fibrils. Some of the transient emission events in the fibrils and adjacent plage may also be related.

Tarbell, T.; Ferguson, S.; Frank, Z.; Title, A.; Topka, K.

1988-01-01

185

Flow cytometric analysis of crayfish haemocytes activated by lipopolysaccharides  

USGS Publications Warehouse

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.

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

2004-01-01

186

The thermodynamic functions of viscous flow activation and structural features of triethylene glycol-aprotic polar solvent binary extractants  

Microsoft Academic Search

The kinematic viscosity of triethylene glycol containing small admixtures of polar aprotic solvents (dimethylsulfoxide, N-methylpyrrolidone,\\u000a and tetramethylenesulfone) was measured. The thermodynamic functions of viscous flow activation and the mean degree of association\\u000a in the binary systems specified at 2060C were calculated and analyzed. The degree of solution structuring was found to be\\u000a determined by the energy component of viscous flow

E. I. Grushova; A. I. Yusevich

2006-01-01

187

Heat and fluid flow characteristics of liquid sodium flowing past a nuclear fuel element with non-uniform energy generation  

Microsoft Academic Search

The prime objective of the present study is to analyze numerically the steady state fluid flow and heat transfer characteristics of liquid sodium as a coolant flowing past over a rectangular nuclear fuel element having non-uniform volumetric energy generation. Accordingly, employing stream function-vorticity formulation and using finite difference schemes, the equations governing the flow and thermal fields in the coolant

M. K. Ramis; G. Jilani

2010-01-01

188

Activities of the Iowa Energy Policy Council in Energy Education.  

ERIC Educational Resources Information Center

This report describes the various energy education programs and projects with which the Iowa Energy Policy Council has been involved since 1976. Briefly summarized are the Council's activities in curriculum development, inservice education, energy extension, and the organization of energy-related special events. (WB)

Heiting, W. Tony

189

Flow characteristics of expansion energy used pneumatic booster  

NASA Astrophysics Data System (ADS)

The most common booster is called input pressure reduced (IPR) booster. However, this type of booster has its own shortages, such as its small output flow, when the boosting ratio is higher, the shortage becomes more distinct. Recent research on pneumatic boosters mainly focused on the factors that influence the characteristics of the boosters, some new kinds of pneumatic booster structures were designed, but the efficiency and output flow of these boosters are still not improved sufficiently. In order to improve the output flow of the pneumatic booster, a new kind of booster, expansion energy used (EEU) booster, is proposed. Non-linear differential equations of the pneumatic booster are set up. By using the software MATLAB/Simulink for simulation, the motion characteristics of the pistons, the characteristics of the output flow of the boosters are obtained for analysis of a principle. The principle, which is used to elevate the output flow of the two kinds of boosters, is that the average pressure of the air in the driving chambers of the EEU booster is higher than that of the IPR booster. The simulation and experimental research of the output flow characteristics are done. The simulation and experimental results are in a good accordance. And the simulation and experimental results show that when the air source pressure and the output pressure are set at 0.6 MPa and 0.8 MPa, respectively, with the increase of the terminal pressure of the air in the driving chamber, the output flow of the IPR booster ascends stably. As the terminal pressure of the air in the driving chamber goes up, the output flow of the EEU booster rises, and later it almost remains constant. In addition, with the same terminal pressure, the output flow of the EEU booster is greater than that of the IPR booster, and the difference decreases when the terminal pressure grows. At last, the output pressure is set at 0.8 MPa, under the optimum work state of the EEU booster, the output flow of the two kinds of boosters all declines with the rise of the boosting ratio. Furthermore, the output flow of the EEU booster is higher than that of IPR booster by 95 L/min approximately. The proposed research lays the foundation for optimistic of the EEU booster.

Shi, Yan; Cai, Maolin; Xu, Weiqing; L, Jie

2012-09-01

190

Hypersonic Flow Control Using Upstream Focused Energy Deposition  

NASA Technical Reports Server (NTRS)

A numerical study of centerline and off-centerline power deposition at a point upstream of a two-dimensional blunt body at Mach 6.5 at 30 km altitude are presented. The full Navier-Stokes equations are used. Wave drag, lift, and pitching moment are presented as a function of amount of power absorbed in the flow and absorption point location. It is shown that wave drag is considerably reduced. Modifications to the pressure distribution in the flow field due to the injected energy create lift and a pitching moment when the injection is off-centerline. This flow control concept may lead to effective ways to improve the performance and to stabilize and control hypersonic vehicles.

Riggins David W.; Nelson, H. F.

1999-01-01

191

Active Control of Instabilities in Laminar BoundaryLayer Flow--Part I: An Overview  

E-print Network

Active Control of Instabilities in Laminar Boundary­Layer Flow-- Part I: An Overview Ronald D laminar flow in a region of the flow in which the natural instabilities, if left unattended, lead the phenomena by­which the automated studies can be used to expand knowledge of flow control. 1 This research

Erlebacher, Gordon

192

Observations of shear flows in high-energy-density plasmas  

NASA Astrophysics Data System (ADS)

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.

Harding, Eric C.

193

Two-photon microscopy to measure blood flow and concurrent brain cell activity  

E-print Network

to examine vascular dynamics and blood flow in multiple brain regions, including somatosensory cortex (4, 9-photon imaging of blood flow dynamics, concurrent with cellular activity, in the somatosenso 1 Two-photon microscopy to measure blood flow and concurrent brain cell activity Running title

Kleinfeld, David

194

OWC wave energy devices with air flow control  

Microsoft Academic Search

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

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

1999-01-01

195

Inhibition of the active lymph pump by flow in rat mesenteric lymphatics and thoracic duct  

NASA Technical Reports Server (NTRS)

There are only a few reports of the influence of imposed flow on an active lymph pump under conditions of controlled intraluminal pressure. Thus, the mechanisms are not clearly defined. Rat mesenteric lymphatics and thoracic ducts were isolated, cannulated and pressurized. Input and output pressures were adjusted to impose various flows. Lymphatic systolic and diastolic diameters were measured and used to determine contraction frequency and pump flow indices. Imposed flow inhibited the active lymph pump in both mesenteric lymphatics and in the thoracic duct. The active pump of the thoracic duct appeared more sensitive to flow than did the active pump of the mesenteric lymphatics. Imposed flow reduced the frequency and amplitude of the contractions and accordingly the active pump flow. Flow-induced inhibition of the active lymph pump followed two temporal patterns. The first pattern was a rapidly developing inhibition of contraction frequency. Upon imposition of flow, the contraction frequency immediately fell and then partially recovered over time during continued flow. This effect was dependent on the magnitude of imposed flow, but did not depend on the direction of flow. The effect also depended upon the rate of change in the direction of flow. The second pattern was a slowly developing reduction of the amplitude of the lymphatic contractions, which increased over time during continued flow. The inhibition of contraction amplitude was dependent on the direction of the imposed flow, but independent of the magnitude of flow. Nitric oxide was partly but not completely responsible for the influence of flow on the mesenteric lymph pump. Exposure to NO mimicked the effects of flow, and inhibition of the NO synthase by N (G)-monomethyl-L-arginine attenuated but did not completely abolish the effects of flow.

Gashev, Anatoliy A.; Davis, Michael J.; Zawieja, David C.; Delp, M. D. (Principal Investigator)

2002-01-01

196

Advanced Redox Flow Batteries for Stationary Electrical Energy Storage  

SciTech Connect

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 Energys 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.

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

2012-03-19

197

Wave turbulence revisited: Where does the energy flow?  

E-print Network

Turbulence in a system of nonlinearly interacting waves is referred to as wave turbulence. It has been known since seminal work by Kolmogorov, that turbulent dynamics is controlled by a directional energy flux through the wavelength scales. We demonstrate that an energy cascade in wave turbulence can be bi-directional, that is, can simultaneously flow towards large and small wavelength scales from the pumping scales at which it is injected. This observation is in sharp contrast to existing experiments and wave turbulence theory where the energy flux only flows in one direction. We demonstrate that the bi-directional energy cascade changes the energy budget in the system and leads to formation of large-scale, large-amplitude waves similar to oceanic rogue waves. To study surface wave turbulence, we took advantage of capillary waves on a free, weakly charged surface of superfluid helium He-II at temperature 1.7K. Although He-II demonstrates non-classical thermomechanical effects and quantized vorticity, waves on its surface are identical to those on a classical Newtonian fluid with extremely low viscosity. The possibility of directly driving a charged surface by an oscillating electric field and the low viscosity of He-II have allowed us to isolate the surface dynamics and study nonlinear surface waves in a range of frequencies much wider than in experiments with classical fluids.

L. V. Abdurakhimov; I. A. Remizov; A. A. Levchenko; G. V. Kolmakov; Y. V. Lvov

2014-04-03

198

Wave turbulence revisited: Where does the energy flow?  

E-print Network

Turbulence in a system of nonlinearly interacting waves is referred to as wave turbulence. It has been known since seminal work by Kolmogorov, that turbulent dynamics is controlled by a directional energy flux through the wavelength scales. We demonstrate that an energy cascade in wave turbulence can be bi-directional, that is, can simultaneously flow towards large and small wavelength scales from the pumping scales at which it is injected. This observation is in sharp contrast to existing experiments and wave turbulence theory where the energy flux only flows in one direction. We demonstrate that the bi-directional energy cascade changes the energy budget in the system and leads to formation of large-scale, large-amplitude waves similar to oceanic rogue waves. To study surface wave turbulence, we took advantage of capillary waves on a free, weakly charged surface of superfluid helium He-II at temperature 1.7K. Although He-II demonstrates non-classical thermomechanical effects and quantized vorticity, waves o...

Abdurakhimov, L V; Levchenko, A A; Kolmakov, G V; Lvov, Y V

2014-01-01

199

Waste to Energy Time Activities  

E-print Network

.D. at the National Technical University of Athens, Department of Chemical Engineering. He is an Expert in Waste University, working with Professor N.J.Themelis in projects related to the waste-to energy technologies, Columbia University, USA (www.wtert.org), 2 Waste-to-Energy Research & Technology Council-SYNERGIA Greece

200

The Flow of Energy: Primary Production to Higher Trophic Levels  

NSDL National Science Digital Library

Today we will explore some of the multiple topics related to the flow of energy in ecosystems. Energy is used up and lost as heat as it moves through ecosystems, and new energy is continually added to the earth in the form of solar radiation. As we learned in the last lecture, the earth is an open system in regard to energy.Nutrients and other materials, on the other hand, are continually recirculated within and among ecosystems, and by and large there are no new inputs or losses from the planet. In terms of materials, then, the earth is a closed system. Both energy and materials are essential to ecosystem structure, function, and composition. You have already been exposed to the basic concepts of nutrient cycles; in this lecture we focus on energy. Note that in terms of the cycling of carbon, "materials" and energy can be inter-converted. For example, we know how many calories (a measure of energy) a gram of certain carbon compounds materials such as fats or carbohydrates contain.

Klink, George

2010-04-08

201

Active flow separation control using synthetic jet actuators  

E-print Network

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...

Rao, Preetham P

2012-06-07

202

Active control of tip clearance flow in axial compressors  

E-print Network

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 ...

Bae, Jinwoo W

2001-01-01

203

CFD-based aero-optical analysis of flow fields over two-dimensional cavities with active flow control  

Microsoft Academic Search

Prediction and control of optical wave front distortions and aberrations in a high energy laser beam due to interaction with an unsteady highly non-uniform flow field is of great importance in the development of directed energy weapon systems for Unmanned Air Vehicles (UAV). The unsteady shear layer over the weapons bay cavity is the primary cause of this distortion of

Yan Tan

2005-01-01

204

Solar energy education. Renewable energy activities for general science  

SciTech Connect

Renewable energy topics are integrated with the study of general science. The literature is provided in the form of a teaching manual and includes such topics as passive solar homes, siting a home for solar energy, and wind power for the home. Other energy topics are explored through library research activities. (BCS)

Not Available

1985-01-01

205

Energy-efficiency testing activities of the Mobile Energy Laboratory  

SciTech Connect

This report summarizes energy-efficiency testing activities during the first and second quarters of fiscal year 1990 applying the Mobile Energy Laboratory (MEL) testing capabilities. Four MELs, developed by the US Department of Energy (DOE) Federal Energy Management Program (FEMP), are administered by Pacific Northwest Laboratory (PNL) for energy testing and program support functions at federal facilities. The using agencies principally fund MEL applications, while DOE/FEMP funds program administration and capability enhancement activities. This report fulfills the requirements established in the MEL Use Plan (PNL-6861) for semiannual reporting on energy-efficiency testing activities using the MEL capabilities. The MEL Use Committee, formally established in 1989, developed the MEL Use Plan and meets semiannually to establish priorities for energy-efficient testing applications using the MEL capabilities.

Parker, G.B.

1991-01-01

206

Magnetotail flows can consume as much solar wind energy as a substorm  

NASA Astrophysics Data System (ADS)

We examine an event on 17 December 1997, during which the Wind and ACE spacecraft measured an extended period of southward interplanetary magnetic field. The high values of the epsilon parameter were interpreted as strong energy input into the magnetotail. Despite this energy input, the polar cap potential and area remained constant over a period of several hours, the inner magnetotail was very quiet, and there were no substorm signatures either in the magnetotail or in the ionosphere. Comparison of data and MHD simulation results show that the energy input to the magnetosphere was enhanced and that this event was not a case where the solar wind monitor would have trouble predicting the interplanetary field reaching the Earth orbit. Both Geotail observations in the tail and the MHD simulations show that a substantial amount of energy was being consumed in the tail flow activity during this period. Order of magnitude estimates indicate that the flows indeed were sufficient to consume the incoming energy in a quasi-continuous even if bursty manner. Observations from the IMAGE meridional magnetometer network reveal that the substorm that followed several hours later was relatively small, and its size was proportional to the energy input after the substorm onset, not to the total energy input since the southward turning of the interplanetary field. It is argued that the continuous flow activity disturbed the formation of the thin current sheet in the inner magnetotail, which led to the delay in the substorm development. However, the controlling factor which finally led to the global instability remains an open issue.

Pulkkinen, T. I.; Tanskanen, E. I.; Wiltberger, M.; Slavin, J. A.; Nagai, T.; Reeves, G. D.; Frank, L. A.; Sigwarth, J. B.

2003-08-01

207

Blended Wing Body Systems Studies: Boundary Layer Ingestion Inlets With Active Flow Control  

NASA Technical Reports Server (NTRS)

A CFD analysis was performed on a Blended Wing Body (BWB) aircraft with advanced, turbofan engines analyzing various inlet configurations atop the aft end of the aircraft. The results are presented showing that the optimal design for best aircraft fuel efficiency would be a configuration with a partially buried engine, short offset diffuser using active flow control, and a D-shaped inlet duct that partially ingests the boundary layer air in flight. The CFD models showed that if active flow control technology can be satisfactorily developed, it might be able to control the inlet flow distortion to the engine fan face and reduce the powerplant performance losses to an acceptable level. The weight and surface area drag benefits of a partially submerged engine shows that it might offset the penalties of ingesting the low energy boundary layer air. The combined airplane performance of such a design might deliver approximately 5.5% better aircraft fuel efficiency over a conventionally designed, pod-mounted engine.

Geiselhart, Karl A. (Technical Monitor); Daggett, David L.; Kawai, Ron; Friedman, Doug

2003-01-01

208

An Energy Principle for Ideal MHD Equilibria with Flows  

SciTech Connect

In the standard ideal MHD energy principle for equilibria with no flows, the stability criterion, which is the defi niteness of the perturbed potential energy, is usually constructed from the linearized equation of motion. Equivalently while more straightforwardly, it can also be obtained from the second variation of the Hamiltonian calculated with proper constraints. For equilibria with flows, a stability criterion was proposed from the linearized equation of motion, but not explained as an energy principle1. In this paper, the second variation of the Hamiltonian is found to provide a stability criterion equivalent to, while more straightforward than, what was constructed from the linearized equation of motion. To calculate the variations of the Hamiltonian, a complete set of constraints on the dynamics of the perturbations is derived from the Euler-Poincare structure of the ideal MHD. In addition, a previous calculation of the second variation of the Hamiltonian was claimed to give a different stability criterion2, and in this paper we argue such a claim is incorrect.

Yao Zhou and Hong Qin

2013-03-11

209

Search for active lava flows with VIRTIS on Venus Express  

NASA Astrophysics Data System (ADS)

There are several lines of evidence suggesting that effusive volcanism still shapes the surface of Venus but the rate is not well constrained. The preservation of impact craters is consistent with a rate of 1 km3/year (comparable to Earth intraplate volcanism) as well as a rate several orders of magnitude less. It has been proposed to search images of the Venus nightside near 1 ?m for the excess thermal emission of active lava flows. The scattering of photons in the optically thick cloud cover is similar in effect to a Gaussian blur with a Full Width Half Maximum (FWHM) of 90 km. This reduces the maximum intensity of the anomalies introduced by eruptions, making detection more difficult than in a clear atmosphere, but also provides larger targets for imaging. The VIRTIS instrument on Venus Express observed surface thermal emission at 1.02 ?m wavelength between April 2006 and October 2008 at a spatial resolution of typically a few tens of km. We have searched the ~1000 images for the signatures of active lava flows in form of transient excess emission measured in several adjacent pixels. We estimate that eruptions with 1GW/?m/sr total excess specific thermal emission would be clearly visible compared to the instrumental and atmospheric noise but no such anomalies were detected. It has been shown that the total thermal emission of eruptions on Earth can be related to the lava discharge rate. We adjust this model to the Venus surface environment by adjusting observed lava surface temperature distributions and estimate that a discharge rate on the order of 1000 m3/s is required to produce an anomaly clearly identifiable in VIRTIS data. This is a relatively high value for effusive volcanism but a few historical eruptions on Earth surpassed it. Adopting a fit to the discharge rates of historical eruptions on Hawaii as a model, 4% to 10% of the eruptions in the field of view of VIRTIS images would have been detectable. In addition to the low detection probability, the low surface coverage of on average 1% of the surface per day over a period of 800 days indicates that the probability of an eruption imaged by VIRTIS was low to begin with. Therefore the VIRTIS data set fails to provide a useful constraint on the rate of volcanism on Venus. Venus Express continues to observe surface thermal emission with the Venus Monitoring camera. For future missions, near infrared imaging would profit from more frequent images of the same area than is possible from the excentric 24h orbit of Venus Express. The superrotation of the cloud cover allows to reduce atmospheric noise by averaging of images taken hours apart and the detection of eruptions with 100 m3/s lava or less might then be possible. Nevertheless, searching for lava flows emplaced between two observations of the same surface by high resolution radar imaging, altimetry or interferometry generally provides a better constraints than infrared imaging for the same observation duration and surface coverage. However, high resolution radar and low resolution infrared observations are highly complementary and could be accommodated on the same mission, preferably with a low circular polar orbit.

Mueller, N. T.; Helbert, J.; Stofan, E. R.; Smrekar, S. E.; Piccioni, G.; Drossart, P.

2012-12-01

210

Translation of SBGN maps: Process Description to Activity Flow  

PubMed Central

Background The Systems Biology Graphical Notation (SBGN) provides standard graphical languages for representing cellular processes, interactions, and biological networks. SBGN consists of three languages: Process Descriptions (PD), Entity Relationships (ER), and Activity Flows (AF). Maps in SBGN PD are often large, detailed, and complex, therefore there is a need for a simplified illustration. Results To solve this problem we define translations of SBGN PD maps into the more abstract SBGN AF maps. We present a template-based translation which allows the user to focus on different aspects of the underlying biological system. We also discuss aspects of laying out the AF map and of interactive navigation between both the PD and the AF map. The methods developed here have been implemented as part of SBGN-ED ( http://www.sbgn-ed.org). Conclusions SBGN PD maps become much smaller and more manageable when translated into SBGN AF. The flexible translation of PD into AF and related interaction methods are an initial step in translating the different SBGN languages and open the path to future research for translation methods between other SBGN languages. PMID:24176088

2013-01-01

211

Midtail plasma flows and the relationship to near-Earth substorm activity: A case study  

NASA Technical Reports Server (NTRS)

Recent simulations of magnetotail reconnection have pointed to a link between plasma flows, dipolarization, and the substorm current wedge. In particular, Hesse and Birn (1991) have proposed that earthward jetting of plasma from the reconnection region transports flux into the near-Earth region. At the inner edge of the plasma sheet this flux piles up, producing a dipolarization of the magnetic field. The vorticity produced by the east-west deflection of the flow at the inner edge of the plasma sheet gives rise to field-aligned currents that have region 1 polarity. Thus in this scenario the earthward flow from the reconnection region produces the dipolarization ad the current wedge in a self-consistent fashion. In this study we examine observations made on April 8, 1985 by the Active Magnetospheric Particle Tracer Explorers (AMPTE)/Ion Release Module (IRM), the geosynchronous satellites 1979-053, 1983-019, and 1984-037, and Syowa station, as well as AE. This event is unique because IRM was located near the neutral sheet in the midnight sector for am extended period of time. Ground data show that there was ongoing activity in the IRM local time sector for several hours, beginning at 1800 UT and reaching a crescendo at 2300 UT. This activity was also accompanied by energetic particle variations, including injections, at geosynchronous orbit in the nighttime sector. Significantly, there were no fast flows at the neutral sheet until the great intensification of activity at 2300 UT. At that time, IRM recorded fast eartheard flow simultaneous with a dipolatization of the magetic field. We conclude that while the aforementioned scenario for the creation of the current wedge encounters serious problems explaining the earlier activity, the observations at 2300 UT are consistent with the scenario of Hesse and Birn (1191). On that basis it is argued that the physics of substorms is not exclusively rooted in the development of a global tearing mode. Processes at the inner edge of the cross-tail current that cause a disruption of the current and a consequent dipolarization and current wedge may be unrelated to the formation of a macroscale reconnection region. Thus the global evolution of a substorm is probably a complicated superposition of such processes operating on a very localized scale and a global macroscale process that allows for such things as releasing te energy stored in lobe flux and creation of plasmoids.

Lopez, R. E.; Goodrich, C. C.; Reeves, G. D.; Belian, R. D.; Taktakishvili, A.

1994-01-01

212

Development of a CouetteTaylor flow device with active minimization of secondary circulation  

E-print Network

with kinematic viscosity Ga 0.3 water and density =6.3 103 kg/m3 at a temperature of 25 °C. Flows developedDevelopment of a Couette­Taylor flow device with active minimization of secondary circulation E shear flows for the study of hydrodynamic and magnetohydrodynamic instabilities which are believed

Ji, Hantao

213

Passive and Active Device for Laminar Flow Control of Swept Wing  

Microsoft Academic Search

Summary Laminar flow control of aircraft gains importance due to both economic and environmental aspects. In this paper several solutions for passive devices and one proposal for an active device for laminar flow control on swept wings are presented. The passive devices concern the anti contamination devices (ACD) which are capable to stop the spanwise propagation of fuselage-induced contaminated flow

J. V. Krier; T. Sucipto; J. P. Godard; R. Donelli; D. Arnal

214

Implementation of electric vehicle system based on solar energy in Singapore assessment of flow batteries for energy storage  

E-print Network

For large-scale energy storage application, flow battery has the advantages of decoupled power and energy management, extended life cycles and relatively low cost of unit energy output ($/kWh). In this thesis, an overview ...

Chen, Yaliang

2009-01-01

215

Policy support activities Brazil Rural Energy  

E-print Network

1 Policy support activities Brazil Rural Energy Enterprise Development (B-REED) Juan Zak UNEP Risoe, but electricity supply to rural areas is not an attractive business for them. #12;4 First policy support 1 that encourages manufacture of alternative energy equipment in Brazil. 2. Replace subsidies via CCC by extension

216

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

NASA Technical Reports Server (NTRS)

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.

Schmid, L. A.

1977-01-01

217

Kinetics of Processes Distributed in Activation Energy  

Microsoft Academic Search

The kinetic behavior of systems in which processes occur which are distributed over a range of activation energies is considered. The effects produced by the initial distribution, the order of reaction, and the frequency factor are discussed. Imaginary and actual experimental situations are used to illustrate the large errors which can result when the distribution of the processes in activation

W. Primak

1955-01-01

218

What is Energy?: Activities and Experiments  

NSDL National Science Digital Library

This website targets teachers, providing them with ideas for simple activities and experiments that can be used to demonstrate concepts related to kinetic and other forms of energy. Each activity and the science concepts involved are clearly delineated. There are also a number of challenge questions suggested to be posted to the students.

2008-06-25

219

Three-dimensional flow dynamics of an active submarine channel  

NASA Astrophysics Data System (ADS)

Field scale submarine channel gravity currents are notoriously difficult to measure and thus directly investigate due to their inaccessible location and infrequent nature, which is compounded by present sea-level high-stand. An exception to this is the almost continuous density-driven current that results from the inflow of saline Mediterranean water, via the Bosporus strait, into the Black Sea. This flow has carved a sinuous channel system in water depths of 70 to 120 m. The relatively shallow depths of the channel and the continuous nature of this current provide a rare opportunity to study three-dimensional flow dynamics and the interaction of the flow with a seafloor channel network. Thus, it provides a rare analogue for channelized dilute sediment-laden turbidity currents. Sediment erosion, transport and deposition within submarine channel bends is primarily controlled by the magnitude and direction of near bed flow. Flow around channel bends is characterized by a helical or spiralling structure. In rivers this helical flow is characterized by near-surface fluid moving toward the outer bank and near-bed fluid moving toward the inner bank. Following fierce debate over the last decade, it is now accepted that helical flow in submarine channel bends can display a variety of complex structures. Most importantly for understanding sediment transport, near bed flow can be directed towards the outer bank, which is in the opposite sense to in a river. The next challenge is to understand what the exact controls on the orientation of helical flow cells within submarine flows are, and their spatial evolution around bends. We present data from the Black Sea showing how the three-dimensional velocity and density of a submarine gravity current evolves at multiple cross sections as the flow travels around a bend. We use this data to calculate the magnitude, relative importance and interaction of centrifugal, coriolis and pressure gradients in controlling the structure of helical cells within the flow. We demonstrate the first order importance of radial pressure gradients, resulting from flow stratification, in controlling the structure of the flow as it travels around the bend.

Sumner, E. J.; Dorrell, R. M.; Peakall, J.; Darby, S. E.; Parsons, D. R.; Wynn, R.

2012-12-01

220

Flow measurement in sodium and water using pulsed-neutron activation: Part 2, experiment  

Microsoft Academic Search

A measurement of water flow on the Experimental Breeder Reactor II (EBR-II) evaporator downcomers, a measurement of sodium flow on the EBR-II secondary sodium system, and a calibration experiment at the University of Utah Water Research Laboratory are three experiments using the pulsed neutron activation (PNA) technique to determine flow rate. The EBR-II data permit calculation of flow rates and

C. C. Price; R. N. Curran; H. L. Larson; J. I. Sackett

1982-01-01

221

Flow activates an endothelial potassium channel to release an endogenous nitrovasodilator.  

PubMed Central

Flow-mediated vasodilation is endothelium dependent. We hypothesized that flow activates a potassium channel on the endothelium, and that activation of this channel leads to the release of the endogenous nitrovasodilator, nitric oxide. To test this hypothesis, rabbit iliac arteries were perfused at varying flow rates, at a constant pressure of 60 mm Hg. Increments in flow induced proportional increases in vessel diameter, which were abolished by L,N-mono-methylarginine (the antagonist of nitric-oxide synthesis). Barium chloride, depolarizing solutions of potassium, verapamil, calcium-free medium, and antagonists of the KCa channel (charybdotoxin, iberiotoxin) also blocked flow-mediated vasodilation. Conversely, responses to other agonists of endothelium-dependent and independent vasodilation were unaffected by charybdotoxin or iberiotoxin. To confirm that flow activated a specific potassium channel to induce the release of nitric oxide, endothelial cells cultured on micro-carrier beads were added to a flow chamber containing a vascular ring without endothelium. Flow-stimulated endothelial cells released a diffusible vasodilator; the degree of vasorelaxation was dependent upon the flow rate. Relaxation was abrogated by barium, tetraethylammonium ion, or charybdotoxin, but was not affected by apamin, glybenclamide, tetrodotoxin, or ouabain. The data suggest that transmission of a hyperpolarizing current from endothelium to the vascular smooth muscle is not necessary for flow-mediated vasodilation. Flow activates a potassium channel (possibly the KCa channel) on the endothelial cell membrane that leads to the release of nitric oxide. Images PMID:1719029

Cooke, J P; Rossitch, E; Andon, N A; Loscalzo, J; Dzau, V J

1991-01-01

222

Laser Activated Flow Regulator for Glaucoma Drainage Devices  

PubMed Central

Purpose To assess the capabilities of a new glaucoma drainage device regulator in controlling fluid flow as well as to demonstrate that this effect may be titratable by noninvasive means. Methods A rigid eye model with two main ports was used. On the first port, we placed a saline solution column. On the second, we placed a glaucoma shunt. We then measured the flow and flow rate through the system. After placing the regulator device on the tip of the tube, we measured again with the intact membrane and with the membrane open 50% and 100%. For the ex vivo testing we used a similar setting, using a cadaveric porcine eye, we measured again the flow and flow rate. However, this time we opened the membrane gradually using laser shots. A one-way analysis of variance and a Fisher's Least Significant Difference test were used for statistical significance. We also calculated the correlation between the numbers of laser shots applied and the main outcomes. Results The flow through the system with the glaucoma drainage device regulator (membrane intact and 50% open) was statistically lower than with the membrane open 100% and without device (P < 0.05). The flow was successfully controlled by the number of laser shots applied, and showed a positive correlation (+ 0.9). The flow rate was almost doubled every 10 shots and statistically lower than without device at all time (P < 0.05). Conclusions The glaucoma drainage device regulator can be controlled noninvasively with laser, and allows titratable control of aqueous flow. Translational Relevance Initial results and evidence from this experiment will justify the initiation of in vivo animal trials with the glaucoma drainage device regulator; which brings us closer to possible human trials and the chance to significantly improve the existing technology to treat glaucoma surgically. PMID:25374772

Olson, Jeffrey L.; Velez-Montoya, Raul; Bhandari, Ramanath

2014-01-01

223

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

Microsoft Academic Search

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, 66106 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

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

2004-01-01

224

Fluid flow and deformation at an active continental margin: The Eel River Basin, California  

Microsoft Academic Search

This dissertation addresses how active fluid flow and recent deformation are related to submarine morphology in the offshore Eel River basin along the northern California continental margin. The Eel River basin is an ideal location to study fluid flow and deformation because it is tectonically active, generates hydrocarbons at depth, and experiences rapid sediment loading. Five seismic reflection surveys of

Janet Wai Ngan Yun

2000-01-01

225

Effect of Heart Rate on Regulative Features of the Cortical Activity-Flow Coupling  

Microsoft Academic Search

Objective: Heart rate plays an important role in compensatory conditions of arterial pressure changes. Very little information, however, exists on its role in the dynamic adjustment of stimulated organ perfusion. We studied the influence of heart rate on the activity-flow coupling mechanism which adapts local cerebral blood flow in accordance with cortical activity. Since it does not affect heart rate

B. Rosengarten; C. Budden; S. Osthaus; M. Kaps

2003-01-01

226

Flow-Microcalorimetric Determination of Cellobiase Activity and Its Inhibition by Glucose  

Microsoft Academic Search

A method for measuring cellobiase activity of the Trichoderma reesei CCF 1853 cellulase complex using a Thermal Activity Monitor and a flow - mix mode is described. The kinetic constant KM and the linear dependence of dQmax\\/dt (the maximum heat flow at the total saturation of enzyme with substrate) on the enzyme concentration were determined. The process of the end

M. Beran; V. Paul?ek

1993-01-01

227

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

E-print Network

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 on models that are made up of low level geo- metric components such as lines, circles and ellipses

Paragios, Nikos

228

Control of Vibratory Energy Harvesters in the Presence of Nonlinearities and Power-Flow Constraints  

NASA Astrophysics Data System (ADS)

Over the past decade, a significant amount of research activity has been devoted to developing electromechanical systems that can convert ambient mechanical vibrations into usable electric power. Such systems, referred to as vibratory energy harvesters, have a number of useful of applications, ranging in scale from self-powered wireless sensors for structural health monitoring in bridges and buildings to energy harvesting from ocean waves. One of the most challenging aspects of this technology concerns the efficient extraction and transmission of power from transducer to storage. Maximizing the rate of power extraction from vibratory energy harvesters is further complicated by the stochastic nature of the disturbance. The primary purpose of this dissertation is to develop feedback control algorithms which optimize the average power generated from stochastically-excited vibratory energy harvesters. This dissertation will illustrate the performance of various controllers using two vibratory energy harvesting systems: an electromagnetic transducer embedded within a flexible structure, and a piezoelectric bimorph cantilever beam. Compared with piezoelectric systems, large-scale electromagnetic systems have received much less attention in the literature despite their ability to generate power at the watt--kilowatt scale. Motivated by this observation, the first part of this dissertation focuses on developing an experimentally validated predictive model of an actively controlled electromagnetic transducer. Following this experimental analysis, linear-quadratic-Gaussian control theory is used to compute unconstrained state feedback controllers for two ideal vibratory energy harvesting systems. This theory is then augmented to account for competing objectives, nonlinearities in the harvester dynamics, and non-quadratic transmission loss models in the electronics. In many vibratory energy harvesting applications, employing a bi-directional power electronic drive to actively control the harvester is infeasible due to the high levels of parasitic power required to operate the drive. For the case where a single-directional drive is used, a constraint on the directionality of power-flow is imposed on the system, which necessitates the use of nonlinear feedback. As such, a sub-optimal controller for power-flow-constrained vibratory energy harvesters is presented, which is analytically guaranteed to outperform the optimal static admittance controller. Finally, the last section of this dissertation explores a numerical approach to compute optimal discretized control manifolds for systems with power-flow constraints. Unlike the sub-optimal nonlinear controller, the numerical controller satisfies the necessary conditions for optimality by solving the stochastic Hamilton-Jacobi equation.

Cassidy, Ian L.

229

Athero-Prone Flow Activation of the SREBP2-NLRP3 Inflammasome Mediates Focal Atherosclerosis  

PubMed Central

Athero-prone flow promotes inflammation in endothelial cells, and this process is critical for pathogenesis of many chronic inflammatory conditions such as coronary and carotid artery atherosclerosis, as well as abdominal aortic aneurysm. Signal mediators activated by athero-prone (disturbed) flow that have been described include NF-?B and protein kinase C, which is very different from athero-protective (steady laminar) flow1. In this issue a publication from Shyys lab shows the critical role of sterol regulatory element binding protein 2 (SREBP2) on athero-prone flow-mediated NLRP3 inflammasome activation2. In particular, they showed that athero-prone flow induced both mature form of SREBP2 (SREBP2-N) and SREBP2 mRNA induction, which transcriptionally increase NADPH oxidase 2 (Nox2) and NLRP3 expression, thereby leading to IL-1? expression and endothelial inflammation (Figure 1). In this editorial, we will briefly review the NLRP3 inflammasome and SREBP activation system, which play a key role in modulating athero-prone flow-mediated EC inflammation. We will also discuss the following important questions for the future; the role of local NLRP3 and IL-1? expression, mechanisms for two different types of flow (athero-prone flow vs. athero-protective flow) on SREBP2 activation, and other NLRP3 activators including thioredoxin-interacting protein (TXNIP). PMID:23838164

Abe, Jun-ichi; Berk, Bradford C.

2013-01-01

230

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

Microsoft Academic Search

A dynamic analysis of future energy and carbon flows (20002050) 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

Nina Holck Sandberg; Helge Bratteb

2012-01-01

231

Sensory flow shaped by active sensing: sensorimotor strategies in electric fish.  

PubMed

Goal-directed behavior in most cases is composed of a sequential order of elementary motor patterns shaped by sensorimotor contingencies. The sensory information acquired thus is structured in both space and time. Here we review the role of motion during the generation of sensory flow focusing on how animals actively shape information by behavioral strategies. We use the well-studied examples of vision in insects and echolocation in bats to describe commonalities of sensory-related behavioral strategies across sensory systems, and evaluate what is currently known about comparable active sensing strategies in electroreception of electric fish. In this sensory system the sensors are dispersed across the animal's body and the carrier source emitting energy used for sensing, the electric organ, is moved while the animal moves. Thus ego-motions strongly influence sensory dynamics. We present, for the first time, data of electric flow during natural probing behavior in Gnathonemus petersii (Mormyridae), which provide evidence for this influence. These data reveal a complex interdependency between the physical input to the receptors and the animal's movements, posture and objects in its environment. Although research on spatiotemporal dynamics in electrolocation is still in its infancy, the emerging field of dynamical sensory systems analysis in electric fish is a promising approach to the study of the link between movement and acquisition of sensory information. PMID:23761474

Hofmann, Volker; Sanguinetti-Scheck, Juan I; Knzel, Silke; Geurten, Bart; Gmez-Sena, Leonel; Engelmann, Jacob

2013-07-01

232

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

SciTech Connect

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.

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

1994-01-01

233

A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus  

SciTech Connect

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.

Raustad, Richard A. [Florida Solar Energy Center

2013-01-01

234

Turbine Tip Clearance Active Flow Control using Plasma Actuators  

Microsoft Academic Search

A low-speed linear cascade was used to examine the tip gap leakage flow and leakage vortex that exists within the low pressure turbine stage of a gas-turbine engine. The cascade array is composed of nine Pratt & Whitney ``PakB\\

Daniel Vanness

2005-01-01

235

Quantum control of energy flow in light harvesting.  

PubMed

Coherent light sources have been widely used in control schemes that exploit quantum interference effects to direct the outcome of photochemical processes. The adaptive shaping of laser pulses is a particularly powerful tool in this context: experimental output as feedback in an iterative learning loop refines the applied laser field to render it best suited to constraints set by the experimenter. This approach has been experimentally implemented to control a variety of processes, but the extent to which coherent excitation can also be used to direct the dynamics of complex molecular systems in a condensed-phase environment remains unclear. Here we report feedback-optimized coherent control over the energy-flow pathways in the light-harvesting antenna complex LH2 from Rhodopseudomonas acidophila, a photosynthetic purple bacterium. We show that phases imprinted by the light field mediate the branching ratio of energy transfer between intra- and intermolecular channels in the complex's donor acceptor system. This result illustrates that molecular complexity need not prevent coherent control, which can thus be extended to probe and affect biological functions. PMID:12037563

Herek, Jennifer L; Wohlleben, Wendel; Cogdell, Richard J; Zeidler, Dirk; Motzkus, Marcus

2002-05-30

236

Solar Energy Project, Activities: Earth Science.  

ERIC Educational Resources Information Center

This guide contains lesson plans and outlines of science activities which present concepts of solar energy in the context of earth science experiments. Each unit presents an introduction; objectives; skills and knowledge needed; materials; method; questions; recommendations for further study; and a teacher information sheet. The teacher

Tullock, Bruce, Ed.; And Others

237

Electrochemical characterisation of activated carbon particles used in redox flow battery electrodes  

Microsoft Academic Search

The Faradaic and non-Faradaic characteristics of a series of activated carbon particles (used to produce composite carbonpolymer electrodes for redox flow cells) have been determined using aqueous electrolytes (sulfuric acid and sodium polysulfide) at 295K. The particles were mounted as a circular section (ca. 0.80cm2) shallow packed bed of 2.5mm thickness in the direction of electrolyte flow (mean linear flow

G. J. W. Radford; J. Cox; R. G. A. Wills; F. C. Walsh

2008-01-01

238

URANS Simulations of Active Flow Control on Highly Loaded Turbomachinery Blades  

Microsoft Academic Search

\\u000a Active flow control is applied on highly loaded turbomachinery blades in order to delay separation, diminish secondary flow\\u000a effects, and thus increase their efficiency. The impact is investigated separately in the context of two key configurations,\\u000a i.e. a compressor cascade and an axial fan. Unsteady Reynolds-Averaged Navier-Stokes simulations are performed to determine\\u000a beneficial flow control parameters. The results are backed

Christoph Gmelin; Mathias Steger; Erik Wassen; Frank Thiele; Andr Huppertz; Marius Swoboda

239

The Magnetic Free Energy in Active Regions  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

240

Blood flow in guinea fowl Numida meleagris as an indicator of energy expenditure by individual muscles during walking and running  

PubMed Central

Running and walking are mechanically complex activities. Leg muscles must exert forces to support weight and provide stability, do work to accelerate the limbs and body centre of mass, and absorb work to act as brakes. Current understanding of energy use during legged locomotion has been limited by the lack of measurements of energy use by individual muscles. Our study is based on the correlation between blood flow and aerobic energy expenditure in active skeletal muscle during locomotion. This correlation is strongly supported by the available evidence concerning control of blood flow to active muscle, and the relationship between blood flow and the rate of muscle oxygen consumption. We used injectable microspheres to measure the blood flow to the hind-limb muscles, and other body tissues, in guinea fowl (Numida meleagris) at rest, and across a range of walking and running speeds. Combined with data concerning the various mechanical functions of the leg muscles, this approach has enabled the first direct estimates of the energetic costs of some of these functions. Cardiac output increased from 350 ml min?1 at rest, to 1700 ml min?1 at a running speed (? 2.6 m s?1) eliciting a of 90% of . The increase in cardiac output was achieved via approximately equal factorial increases in heart rate and stroke volume. Approximately 90% of the increased cardiac output was directed to the active muscles of the hind limbs, without redistribution of blood flow from the viscera. Values of mass-specific blood flow to the ventricles, ? 15 ml min?1 g?1, and one of the hind-limb muscles, ? 9 ml min?1 g?1, were the highest yet recorded for blood flow to active muscle. The patterns of increasing blood flow with increasing speed varied greatly among different muscles. The increases in flow correlated with the likely fibre type distribution of the muscles. Muscles expected to have many high-oxidative fibres preferentially increased flow at low exercise intensities. We estimated substantial energetic costs associated with swinging the limbs, co-contraction to stabilize the knee and work production by the hind-limb muscles. Our data provide a basis for evaluating hypotheses relating the mechanics and energetics of legged locomotion. PMID:15731191

Ellerby, David J; Henry, Havalee T; Carr, Jennifer A; Buchanan, Cindy I; Marsh, Richard L

2005-01-01

241

Efficient Ionization Investigation for Flow Control and Energy Extraction  

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

242

Evaluation of nutrient removal efficiency and microbial enzyme activity in a baffled subsurface-flow constructed wetland system.  

PubMed

In this study, the enzyme activities and their relationships to domestic wastewater purification are investigated in four different types of subsurface-flow constructed wetlands (CWs), namely the traditional horizontal subsurface-flow, horizontal baffled subsurface-flow, vertical baffled subsurface-flow, and composite baffled subsurface-flow CWs. Results showed that the urease activity in the composite baffled subsurface-flow CW was significantly higher than in the other three CWs, while the phosphatase activity in the vertical baffled subsurface-flow CW were higher than in the other three CWs. There were significant and very significant correlations between the activities of urease and the removal rates of TN and NH4(+)-N for the horizontal baffled flow, horizontal subsurface flow, and composite baffled subsurface flow CWs. This study suggests that the activity of urease in the root zones of those three CWs is an important indicator for N purification from wastewaters. PMID:23982062

Cui, Lihua; Ouyang, Ying; Gu, Wenjie; Yang, Weizhi; Xu, Qiaoling

2013-10-01

243

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

SciTech Connect

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.

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

1995-06-01

244

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

Microsoft Academic Search

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.

V. Yu. Borzov; I. V. Rybka

1995-01-01

245

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

Microsoft Academic Search

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.

V. Yu. Borzov; I. V. Rybka; A. S. Yur'ev

1994-01-01

246

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

E-print Network

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 ...

Kurd, Michael Omar, 1982-

2004-01-01

247

77 FR 3544 - Meeting and Webinar on the Active Traffic and Demand Management and Intelligent Network Flow...  

Federal Register 2010, 2011, 2012, 2013

...Webinar on the Active Traffic and Demand Management and Intelligent Network Flow Optimization Operational Concepts...input on the Active Traffic and Demand Management (ADTM) and Intelligent Network Flow Optimization (INFLO)...

2012-01-24

248

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

Microsoft Academic Search

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

Hiroki Ohura; Toshihiko Imato; Yasukazu Asano; Sumio Yamasaki

1998-01-01

249

Numerical Modeling of Active Flow Control in a Boundary Layer Ingesting Offset Inlet  

Microsoft Academic Search

This investigation evaluates the numerical prediction of flow distortion and pressure recovery for a bound- ary layer ingesting offset inlet with active flow control devices. The numerical simulations are computed using a Reynolds averaged Navier-Stokes code developed at NASA. The numerical results are validated by compar- ison to experimental wind tunnel tests conducted at NASA Langley Research Center at both

Brian G. Allan; Lewis R. Owens; Bobby L. Berrier

2004-01-01

250

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

Microsoft Academic Search

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

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

2010-01-01

251

Fluid flow during active oblique convergence: A Southern Alps model from mechanical and geochemical observations  

Microsoft Academic Search

On the basis of combined mechanical modeling and isotopic observations, we propose a Southern Alps paradigm for application to fluid-flow regimes of active oblique collision zones subject to orographic precipitation. The model is derived from four spatial correlations among patterns in the distribution of mechanical forces that drive fluid flow, structural permeability, and isotopic signature. (1) A strong meteoric overprint

P. O. Koons; D. Craw; S. C. Cox; P. Upton; A. S. Templeton; C. P. Chamberlain

1998-01-01

252

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

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

253

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

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

254

Efficient chemical oxygen-iodine laser with longitudinal flow of the active medium  

SciTech Connect

A chemical oxygen-iodine laser with fast flow of the active medium along the optic axis was constructed. Lasing with an output power of 186 W and a chemical efficiency in excess of 20% were achieved. (lasers)

Zagidullin, M V; Nikolaev, V D; Svistun, M I; Khvatov, N A [Samara Branch of the P.N. Lebedev Physics Institute, Russian Academy of Sciences, Samara (Russian Federation)

1999-02-28

255

Dynamic assay of enzyme activities in single cells by flow cytometry.  

PubMed

Three enzymes in single cells were assayed dynamically by flow cytometry using four fluorogenic substrates. Acid phosphatase was determined with 7-bromo-3-hydroxy-2-naphtho-o-anisidine (naphthol AS-BI) phosphate and 4-methylumbelliferone (MU) phosphate, neutral esterase with fluorescein diacetate, and lactic dehydrogenase with NAD-sodium lactate. Fluorescence measurements obtained with the flow cytometer were converted into relative specific enzyme activities for single cells with molar fluorescence coefficients determined with a spectrofluorometer. Specific activities obtained from spectrofluorometric data were compared with activities calculated from flow cytometeric data. Flow cytometric assays gave lower specific single cell activities for 4-methylumbelliferone phosphate hydrolysis and for lactic dehydrogenase than did similar assays by standard spectrofluorometry. Product diffusion may be the greatest cause for this discrepancy. PMID:230257

Dolbeare, F

1979-12-01

256

An Active Region Model for Capturing Fractal Flow Patterns inUnsaturated Soils: Model Development  

SciTech Connect

Preferential flow commonly observed in unsaturated soils allows rapid movement of solute from the soil surface or vadose zone to the groundwater, bypassing a significant volume of unsaturated soil and increasing the risk of groundwater contamination. A variety of evidence indicates that complex preferential patterns observed from fields are fractals. In this study, we developed a relatively simple active region model to incorporate the fractal flow pattern into the continuum approach. In the model, the flow domain is divided into active and inactive regions. Flow occurs preferentially in the active region (characterized by fractals), and inactive region is simply bypassed. A new constitutive relationship (the portion of the active region as a function of saturation) was derived. The validity of the proposed model is demonstrated by the consistency between field observations and the new constitutive relationship.

Liu, Hui-Hai; Zhang, R.; Bodvarsson, Gudmundur S.

2005-06-11

257

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

SciTech Connect

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.

Ayad, S.S.

1981-11-01

258

Flow-injection-type biosensor system for salivary amylase activity  

Microsoft Academic Search

The authors aim to establish a method that can quantitatively evaluate vital reactions to stress. We have been examining the correlation between stress and salivary amylase activity in order to verify its validity as a stress index. In order to quantify human stress, which changes over time, the relationship between stress and salivary amylase activity must be verified by fast

Masaki Yamaguchi; Masashi Kanemaru; Takahiro Kanemori; Yasufumi Mizuno

2003-01-01

259

Theory of materials and energy flow analysis in ecology and economics  

Microsoft Academic Search

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

Sangwon Suha

260

STABLE BLOW UP DYNAMICS FOR THE 1-COROTATIONAL ENERGY CRITICAL HARMONIC HEAT FLOW  

E-print Network

STABLE BLOW UP DYNAMICS FOR THE 1-COROTATIONAL ENERGY CRITICAL HARMONIC HEAT FLOW PIERRE RAPHA?L AND R?MI SCHWEYER Abstract. We exhibit a stable finite time blow up regime for the 1-corotational energy where no nontrivial harmonic map exists. 1.2. Corotational flows. The existence of blow up solutions has

Raphaël, Pierre

261

Simulating Vibrational Energy Flow in Proteins: Relaxation Rate and Mechanism for Heme Cooling in Cytochrome c  

E-print Network

Simulating Vibrational Energy Flow in Proteins: Relaxation Rate and Mechanism for Heme Cooling process.4 Moreover, the recent studies suggested a mechanism of spatially anisotropic directed energy flow 02215 ReceiVed: April 30, 2003; In Final Form: July 24, 2003 The rate and mechanism of the kinetic

Straub, John E.

262

On the sensitivity of the energy of vanishing flow towards mass asymmetry of colliding nuclei  

E-print Network

We demonstrate the role of the mass asymmetry in the energy of vanishing flow by studying asymmetric reactions throughout the periodic table and over entire colliding geometry. Our results, which are almost independent of the system size and as well as of the colliding geometries indicate a sizable effect of the asymmetry of the reaction on the energy of vanishing flow.

Supriya Goyal; Rajeev K. Puri

2011-04-16

263

A comparison of the thermal characteristics of active lava flows and forest fires  

Microsoft Academic Search

Landsat TM data of active lava flows from Kilauea Volcano Hawaii (7\\/23\\/91) and forest fire within Yellowstone National Park (9\\/8\\/88) are compared to show the differences in the spectral and spatial distribution of radiance. At visible wavelengths, smoke from forest firest obscures terrain features, while active eruptions show little degassing at breakouts (ruptured lava tubes). Lava flows exhibit a gradual

Luke P. Flynn; Peter J. Mouginis-Mark

1995-01-01

264

A comparison of the thermal characteristics of active lava flows and forest fires  

Microsoft Academic Search

Landsat TM data of active lava flows from Kilauea Volcano Hawaii (7\\/23\\/91) and forest fires within Yellowstone National Park (9\\/8\\/88) are compared to show the differences in the spectral and spatial distribution of radiance. At visible wavelengths, smoke from forest fires obscures terrain features, while active eruptions show little degassing at breakouts (ruptured lava tubes). Lava flows exhibit a gradual

Luke P. Flynn; Peter J. Mouginis-Mark

1995-01-01

265

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

E-print Network

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...

Babbar, Yogesh

2011-08-08

266

Energy Expenditure During Extravehicular Activity Through Apollo  

NASA Technical Reports Server (NTRS)

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.

Paul, Heather L.

2012-01-01

267

Energy Expenditure During Extravehicular Activity Through Apollo  

NASA Technical Reports Server (NTRS)

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.

Paul, Heather L.

2011-01-01

268

Dielectric barrier plasma dynamics for active control of separated flows  

SciTech Connect

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.

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

269

Nonstationary flow in a channel with variable cross section under conditions of periodic pulsed energy supply  

NASA Astrophysics Data System (ADS)

The effect of a periodic pulsed supply of energy, equal to that of hydrogen combustion in air, on the structure of a supersonic flow in a channel of variable cross section modeling a ramjet tract has been studied. The flow has been numerically simulated based on two-dimensional gasdynamic equations. Various flow regimes are obtained depending on the configuration of energy supply zones and the excess air ratio in the channel.

Zamuraev, V. P.; Kalinina, A. P.

2007-04-01

270

Numerical Modeling of Active Flow Control in a Boundary Layer Ingesting Offset Inlet  

NASA Technical Reports Server (NTRS)

This investigation evaluates the numerical prediction of flow distortion and pressure recovery for a boundary layer ingesting offset inlet with active flow control devices. The numerical simulations are computed using a Reynolds averaged Navier-Stokes code developed at NASA. The numerical results are validated by comparison to experimental wind tunnel tests conducted at NASA Langley Research Center at both low and high Mach numbers. Baseline comparisons showed good agreement between numerical and experimental results. Numerical simulations for the inlet with passive and active flow control also showed good agreement at low Mach numbers where experimental data has already been acquired. Numerical simulations of the inlet at high Mach numbers with flow control jets showed an improvement of the flow distortion. Studies on the location of the jet actuators, for the high Mach number case, were conducted to provide guidance for the design of a future experimental wind tunnel test.

Allan, Brian G.; Owens, Lewis R.; Berrier, Bobby L.

2004-01-01

271

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

NASA Astrophysics Data System (ADS)

We investigate the regional fluid flow dynamics in a highly faulted transform area, the Tjrnes Fracture Zone in northern Iceland which is characterized by steep geothermal gradients, hydrothermal activity, and strong seismicity. We simulate fluid flow within the Tjrnes Fracture Zone using a high-resolution model that was based on the available geological and geophysical data and has the aim to represent the complex geological structures and the thermodynamical processes that drive the regional fluid flow in a physically realistic way. Our results show that convective heat flow and mixing of cold and saline seawater with deep hydrothermal fluids controls the large-scale fluid flow. The distribution of faults has a strong influence on the local hydrodynamics by focusing flow around clusters of faults. This explains the nature of isolated upflow zones of hot hydrothermal fluids which are observed in the Tjrnes Fracture Zone. An important emergent characteristic of the regional fluid flow in the Tjrnes Fracture Zone are two separate flow systems: one in the sedimentary basins, comprising more vigorous convection, and one in the crystalline basement, which is dominated by conduction. These two flow systems yield fundamental insight into the connection between regional hydrothermal fluid flow and seismicity because they form the basis of a toggle switch mechanism that is thought to have caused the hydrogeochemical anomalies recorded at Hsavik before and after the 5.8 M earthquake in September 2002.

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

2010-05-01

272

Steady flows in the chromosphere and transition-zone above active regions as observed by OSO-8  

NASA Technical Reports Server (NTRS)

Two years of data from the University of Colorado ultraviolet spectrometer aboard OSO-8 were searched for steady line-of-sight flows in the chromosphere and transition-zone above active regions. The most conspicuous pattern that emerges from this data set is that many sunspots show persistent blueshifts of transition-zone lines indicating velocities of about 20 km/s with respect to the surrounding plage areas. The data show much smaller shifts in ultraviolet emission lines arising from the chromosphere: the shifts are frequently to the blue, but sometimes redshifts do occur. Plage areas often show a redshift of the transition-zone lines relative to the surrounding quiet areas, and a strong gradient of the vertical component of the velocity is evident in many plages. One area of persistent blueshift was observed in the transition-zone above an active region filament. The energy requirement of these steady flows over sunspots is discussed.

Lites, B. W.

1980-01-01

273

Science. Iowa Developed Energy Activity Sampler, 6-12. Revised.  

ERIC Educational Resources Information Center

The revised Iowa Developed Energy Activity Sampler (IDEAS) was compiled using the original IDEAS program and the Energy Conservation Activity Packets (ECAPS). This document is one of the series of revised IDEAS booklets, and provides activities for teaching science. The activities are intended to present energy principles in an interesting manner

Iowa State Dept. of Education, Des Moines.

274

Mathematics. Iowa Developed Energy Activity Sampler, 6-12. Revised.  

ERIC Educational Resources Information Center

The revised Iowa Developed Energy Activity Sampler (IDEAS) was compiled using the original IDEAS program and the Energy Conservation Activity Packets (ECAPS). This document is one of the series of revised IDEAS booklets, and provides activities for teaching mathematics. The activities are intended to present energy principles in an interesting

Iowa State Dept. of Education, Des Moines.

275

Science. Iowa Developed Energy Activity Sampler, 6-12. Revised.  

ERIC Educational Resources Information Center

The revised Iowa Developed Energy Activity Sampler (IDEAS) was compiled using the original IDEAS program and the Energy Conservation Activity Packets (ECAPS). This document is one of a series of revised IDEAS booklets, and provides activities for teaching science. The activities are intended to present energy principles in an interesting manner

Iowa State Dept. of Education, Des Moines. Div. of Instructional Services.

276

High Energy Activation Data Library (HEAD-2009)  

E-print Network

A proton activation data library for 682 nuclides from 1-H to 210-Po 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.

Yury A. Korovin; Anatoly A. Natalenko; Alexander Yu. Konobeyev; Alexey Yu. Stankovskiy; Stepan G. Mashnik

2010-03-10

277

Transverse Energy Flow with Forward and Central Jets at the LHC  

E-print Network

At the LHC, using forward + central detectors, it becomes possible for the first time to carry out measurements of the transverse energy flow due to ``minijets" accompanying production of two jets separated by a large rapidity interval. We discuss parton-shower calculations of energy flow observables in a high-energy factorized Monte Carlo framework, and comment on the role of these observables to study high parton multiplicity effects.

M. Deak; F. Hautmann; H. Jung; K. Kutak

2011-12-29

278

Energy flow and nutrient cycling in salamander populations in the Hubbard Brook Experimental Forest, New Hampshire  

Microsoft Academic Search

Energy flow through salamander populations in the Hubbard Brook Ecosystem is about 11,000 kcal\\/ha yr (=46,000 kJ\\/ha yr). This is approx. = 0.02% of the net primary productivity, and is approx. = 20% of the energy flow through bird and mammal populations. Salamanders are efficient (60%) at converting ingested energy into new tissue and produce more new tissue annually than

T. M. Burton; G. E. Likens

1975-01-01

279

Crohn's disease activity assessed by doppler sonography: the role of aortic flow parameters  

PubMed Central

OBJECTIVES: Intestinal neovascularization and abnormal abdominal arterial flow rates have been reported in Crohn's disease. The aim of this study was to evaluate Doppler sonography as a method for assessing Crohn's disease activity based on changes in splanchnic hemodynamics. METHODS: Forty-eight patients with Crohn's disease, 22 healthy volunteers and 12 patients with irritable bowel syndrome were evaluated by Doppler ultrasound for flow parameters of the aorta and superior mesenteric artery. This evaluation included the cross-sectional area, maximum flow volume, peak systolic velocity, end diastolic velocity, resistance and the pulsatility index. Disease activity was classified according to the Crohn's disease activity index. RESULTS: Most measurements in the aorta and superior mesenteric artery were significantly different between Crohn's disease patients and both control groups. Only the aortic maximum flow volume (CC?=?0.37, p?=?0.009) and aortic peak systolic velocity (CC?=?0.30, p?=?0.035) showed a significant positive correlation with the Crohn's disease activity index. The determination of cut-off points for the aortic maximum flow volume and peak systolic velocity measurements increased the sensitivity (80 and 75% for flow volume and velocity, respectively), specificity (57 and 75%), accuracy (67 and 75%) and positive (57 and 68%) and negative (80 and 81%) predictive values. These cut-off values permitted the correct classification of most of the patients with Crohn's disease with respect to disease activity. None of the superior mesenteric artery measurements were able to discriminate patients in relation to disease activity. CONCLUSION: The aortic maximum flow volume and peak systolic velocity levels estimated by Doppler sonography reflected disease activity in Crohn's disease. Doppler sonography of the aorta is therefore a novel noninvasive adjunct method that may be useful in the clinical follow-up of patients with Crohn's disease. PMID:23778348

Andrade, Thais Guarana; Fogaca, Homero Soares; Elia, Celeste Carvalho Siqueira; Pitrowsky, Melissa Tassano; de Souza, Heitor Siffert Pereira

2013-01-01

280

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

SciTech Connect

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.

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

1983-09-30

281

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

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

Jones, John, Ed.

282

Active Control of Instabilities in Laminar BoundaryLayer Flow --Part II: Use of Sensors and Spectral Controller  

E-print Network

Active Control of Instabilities in Laminar Boundary­Layer Flow -- Part II: Use of Sensors the presumption of wave cancella­ tion. Joslin et al. 1 have definitively shown that flow control by wave automated control to external flow over an actual aircraft or to any flow which has instabilities

Erlebacher, Gordon

283

A Model for Variable Levee Formation Rates in an Active Lava Flow  

NASA Technical Reports Server (NTRS)

Channelized lava flows on Mars and the Earth often feature levees and collateral margins that change in volume along the path of the flow. Consistent with field observations of terrestrial flows, this suggests that the rate of levee formation varies with distance and other factors. Previous models have assumed a constant rate of levee growth, specified by a single parameter, lambda. The rate of levee formation for lava flows is a good indicator of the mass eruption rate and rheology of the flow. Insight into levee formation will help us better understand whether or not the effusion rate was constant during an eruption, and once local topography is considered, allows us to look at cooling and/or rheology changes downslope. Here we present a more realistic extension of the levee formation model that treats the rate of levee growth as a function of distance along the flow path. We show how this model can be used with a terrestrial flow and a long lava flow on Mars. The key statement of the new formulation is the rate of transfer from the active component to the levees (or other passive components) through an element dx along the path of the flow. This volumetric transfer equation is presented.

Glaze, L. S.; Baloga, S. M.; Mouginis-Mark, P.; Crisp, J.

2004-01-01

284

On active surge control of compressors using a mass flow Bjrnar Bhagen and Jan Tommy Gravdahl  

E-print Network

, the stable operating region of centrifugal compressors is bounded due to the occur- rence of surge. SurgeOn active surge control of compressors using a mass flow observer Bjørnar Bøhagen and Jan Tommy the drive torque of the compressors drive unit as the control variable in an active surge control system

Gravdahl, Jan Tommy

285

Temperature-Gated Thermal Rectifier for Active Heat Flow Control Kedar Hippalgaonkar,,  

E-print Network

Temperature-Gated Thermal Rectifier for Active Heat Flow Control Jia Zhu,, Kedar Hippalgaonkar. In the "Rectifier" state, we observe up to 28% thermal rectification. In the "Resistor" state, the thermal of solid-state active-thermal devices with a large rectification in the Rectifier state. This temperature

Wu, Junqiao

286

Dielectric barrier plasma dynamics for active control of separated flows Subrata Roya  

E-print Network

in propulsion,1 external aerodynamics about an aircraft wing where an efficient passive2 or active control3Dielectric barrier plasma dynamics for active control of separated flows Subrata Roya and K. P geometric and electrical operating parameters is elucidated. © 2006 American Institute of Physics. DOI: 10

Roy, Subrata

287

Experimental investigation into cutting forces and active grain density during abrasive flow machining  

Microsoft Academic Search

It is important to know cutting force components and active grain density during abrasive flow machining (AFM) as this information could be used to evaluate the mechanism involved in AFM. The results show that cutting force components and active grain density govern the surface roughness produced during AFM process. In this paper, an attempt has been made to study the

V. K Gorana; V. K Jain; G. K Lal

2004-01-01

288

Waste-Lithium-Liquid (WLL) Flow Battery for Stationary Energy Storage Applications Youngsik Kim* and Nina MahootcheianAsl  

E-print Network

Waste-Lithium-Liquid (WLL) Flow Battery for Stationary Energy Storage Applications Youngsik Kim in a Waste-Lithium-Liquid (WLL) flow battery that can be used in a stationary energy storage application. Li

Zhou, Yaoqi

289

Separated Vs. homogeneous two-phase flow in violent strombolian activity  

NASA Astrophysics Data System (ADS)

The term "violent Strombolian" was first used to describe mafic eruptions that formed ash-charged columns up to 6 km high, and dispersed material up to a few hundred km from the source (Walker, 1971). These eruptions are often discontinuous and strongly pulsatory and are typically associated with simultaneous effusive activity: they form composite deposits constituted by a cinder cone, tephra blanket, and lava flows spreading from lateral vents. This eruptive regime is typical of water-rich mafic magmas and is characterized by average mass flows (103-105 kg/s) intermediate between Hawaiian and subplinian regimes. Within this interval, there is a direct correlation between explosivity, as defined by tephra production, and magma flux. When magma flow exceeds 105 kg/s, gas segregation is no longer possible and eruptive activity takes the form of sustained columns (subplinian to plinian activity). At eruption rates below 103 kg/s passive degassing processes dominate, causing lava effusion and/or mild explosive activity (Strombolian to Hawaiian). We suggest that very shallow gas segregation processes play a fundamental role in violent strombolian dynamics, affecting both explosive and effusive activity. Simultaneous eruption of tephra from the cone and lava flows from lateral vents requires both a gas-rich mixture ascending the central conduit and gas-poor lava flowing in the lateral system. Uneven distribution of liquid and gas phases is possible only when gas and magma are characterized by different momentum, i.e. the flow is separated. At a first approximation, the phase distribution is controlled by the two-phase flow regime (bubbly, slug, churn or annular), both gas and liquid fluxes, and the ratio between conduit and dike diameters. To quantify this process, we analyze in detail the dynamics of a particularly long-lived and well-known eruption of the last century- the Paricutin eruption (1943-1952) of central Mexico. Specific two-phase flow models are then used to evaluate 1) the effect of separated flow in magma splitting between a central conduit and a lateral dike system, 2) the flow regime that can develop in the central conduit 3) the potential effect on the explosive dynamics. Our results indicate that the explosivity of the eruption was strongly increased by segregation processes, promoting shallow fragmentation of the magma, and that the pulsatory dynamics was likely related to unstable, transitional two-phase flow regimes typical of gas fluxes intermediate between slug and annular flow.

Pioli, L.; Cashman, K.; Wallace, P.

2007-12-01

290

Magnetospheric energy budget during huge geomagnetic activity using Cluster and ground-based data  

Microsoft Academic Search

The Cluster spacecraft crossed the magnetopause at the duskward flank of the tail while the European Incoherent Scatter (EISCAT) radars and magnetometers observed the ionosphere during a sequence of intense substorm-like geomagnetic activity in October 2003. We attempt to estimate the local and global energy flow from the magnetosheath into the magnetotail and the ionosphere under these extreme conditions. We

L. Rosenqvist; S. Buchert; H. Opgenoorth; A. Vaivads; G. Lu

2006-01-01

291

Experimental results using active control of traveling wave power flow  

NASA Technical Reports Server (NTRS)

Active structural control experiments conducted on a 24-ft pinned-free beam derived feedback compensators on the basis of a traveling-wave approach. A compensator is thus obtained which eliminates resonant behavior by absorbing all impinging power. A causal solution is derived for this noncausal compensator which mimics its behavior in a given frequency range, using the Wiener-Hopf. This optimal Wiener-Hopf compensator's structure-damping performance is found to exceed any obtainable by means of rate feedback. Performance limitations encompassed the discovery of frequencies above which the sensor and actuator were no longer dual and an inadvertent coupling of the control hardware to unmodeled structure torsion modes.

Miller, David W.; Hall, Steven R.

1991-01-01

292

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

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

293

Nonstationary flow in the model channel of a ramjet engine in pulse-periodic energy supply  

NASA Astrophysics Data System (ADS)

A study has been made of the influence of the pulse-periodic supply of energy that is equal to the energy released in the combustion of hydrogen in air on the structure of supersonic flow in a channel of variable cross section, modeling the duct of a ramjet engine. The flow has been modeled on the basis of two-dimensional nonstationary gas-dynamic equations. Different flow regimes have been obtained depending on the configuration of the zones of energy supply and the excess-air coefficients.

Zamuraev, V. P.; Kalinina, A. P.

2008-05-01

294

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

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

295

Active Fail-Safe Micro-Array Flow Control for Advanced Embedded Propulsion Systems  

NASA Technical Reports Server (NTRS)

The primary objective of this research effort was to develop and analytically demonstrate enhanced first generation active "fail-safe" hybrid flow-control techniques to simultaneously manage the boundary layer on the vehicle fore-body and to control the secondary flow generated within modern serpentine or embedded inlet S-duct configurations. The enhanced first-generation technique focused on both micro-vanes and micro-ramps highly-integrated with micro -jets to provide nonlinear augmentation for the "strength' or effectiveness of highly-integrated flow control systems. The study focused on the micro -jet mass flow ratio (Wjet/Waip) range from 0.10 to 0.30 percent and jet total pressure ratios (Pjet/Po) from 1.0 to 3.0. The engine bleed airflow range under study represents about a 10 fold decrease in micro -jet airflow than previously required. Therefore, by pre-conditioning, or injecting a very small amount of high-pressure jet flow into the vortex generated by the micro-vane and/or micro-ramp, active flow control is achieved and substantial augmentation of the controlling flow is realized.

Anderson, Bernhard H.; Mace, James L.; Mani, Mori

2009-01-01

296

Diffuse Elevated MIBG Activity in the Renal Parenchyma Caused by Compromised Renal Blood Flow.  

PubMed

Increased metaiodobenzylguanidine (MIBG) activity in the kidneys is usually focal and commonly attributed to radioactive urine accumulation in the renal pelvis. Hereby, we present 2 cases of abnormal diffuse MIBG activity in the kidneys caused by compromised renal blood flow. The patterns should be differentiated from physiologic renal MIBG activity, especially when the uptake is relatively symmetric as well as from regional MIBG-avid disease. PMID:24999702

Liu, Bin; Codreanu, Ion; Yang, Jigang; Servaes, Sabah; Zhuang, Hongming

2014-11-01

297

Tumulus development on lava flows: insights from observations of active tumuli and analysis of formation models  

NASA Astrophysics Data System (ADS)

Here, we use observations of active flows along with detailed morphometric field measurements of more than 70 tumuli on flows at Mount Etna (Italy), Kilauea, and Hualalai (US) volcanoes to constrain a previously published model that estimates the pressure needed to form tumuli. In an attempt to discover the nature and magnitude of pressure variations within active lava flow interiors, we then consider how tumuli differ from idealized circular plates. We incorporate observations of active tumuli and find that they may grow asymmetrically yet produce a symmetrical tumulus and can form where the flow path significantly changes direction. Bending models of clamped edges provide the most reasonable head estimates for the tumuli in our study. Tumulus formation requires the proper combination of cooling and effusion rate. If cooling is too extensive and effusion rate too low, the crust will provide too much resistance to bending. If cooling is too limited and effusion rates too high, crusts will not develop or have insufficient strength to resist fracture and subsequent breakouts. We do not find it surprising that tumuli are rarely found over well-established lava tubes that typically have rigid, walls/overlying crusts that exceed 2 m in thickness and provide too much resistance to bending. Silicic flows lack tumuli because the viscosity gradients within the flow are insufficient to concentrate stress in a localized area.

Anderson, Steven W.; Smrekar, Suzanne E.; Stofan, Ellen R.

2012-05-01

298

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

299

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

Microsoft Academic Search

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

Tainzhen Hong; Xaiobing Liu

2009-01-01

300

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

Microsoft Academic Search

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

Xiaobing Liu; Tianzhen Hong

2010-01-01

301

Optimal frequency for flow energy harvesting using flapping foils and its relation with wake instability  

Microsoft Academic Search

Inspired by the correlation between the propulsion efficiency of a flapping foil propeller and stability of the wake behind it (which leads to the optimal Strouhal number for propulsion), we numerically simulated a foil in energy harvesting mode, and investigated the relation between wake stability and the energy harvesting efficiency (defined as the portion of incoming flow energy extracted by

Qiang Zhu

2010-01-01

302

A software application for energy flow simulation of a grid connected photovoltaic system  

Microsoft Academic Search

A computer software application was developed to simulate hourly energy flow of a grid connected photovoltaic system. This software application enables conducting an operational evaluation of a studied photovoltaic system in terms of energy exchange with the electrical grid. The system model consists of a photovoltaic array, a converter and an optional generic energy storage component that supports scheduled charging\\/discharging.

Ayman A. Hamad; Mohammad A. Alsaad

2010-01-01

303

Asymptotic Approximations to the Distributed Activation Energy Model  

E-print Network

Asymptotic Approximations to the Distributed Activation Energy Model M.J.McGuinness1 , E. Donskoi2 Activation Energy Model (DAEM) also known as the multiple reaction model (MRM), which is widely used in com by a continuum distribution in activation energy of individual re- actions. An individual reaction

McGuinness, Mark

304

IBM Systems Director Active Energy Manager Installation and User's Guide  

E-print Network

IBM Systems Director Active Energy Manager Installation and User's Guide Version 4.3 #12;#12;IBM Systems Director Active Energy Manager Installation and User's Guide Version 4.3 #12;ii IBM Systems Director Active Energy Manager: Installation and User's Guide #12;About this book This book provides

305

Mathematics. Iowa Developed Energy Activity Sampler, 6-12. Revised.  

ERIC Educational Resources Information Center

The revised Iowa Developed Energy Activity Sampler (IDEAS) was compiled using the original IDEAS program and the Energy Conservation Activity Packets (ECAPS). This document contains teaching activities which are intended to strengthen students' mathematics skills and concepts, while broadening their understanding of energy concepts. Each of the 24

Iowa State Dept. of Education, Des Moines. Div. of Instructional Services.

306

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

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

307

Modeling Hot Gas Flow in the Low-luminosity Active Galactic Nucleus of NGC 3115  

NASA Astrophysics Data System (ADS)

Based on the dynamical black hole (BH) mass estimates, NGC 3115 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 1 Ms Chandra X-ray visionary project observations of the NGC 3115 nucleus resolved hot tenuous gas, which fuels the AGN. In this paper 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 from the stars and supernova explosions. We incorporate electron heat conduction as the small-scale feedback mechanism, the gravitational pull of the stellar mass, cooling, and Coulomb collisions. Fitting simulated X-ray emission to the spatially and spectrally resolved observed data, we find the best-fitting solutions with ?2/dof = 1.00 for dof = 236 both with and without conduction. The radial modeling favors a low BH mass <1.3 109 M ?. The best-fitting supernova rate and the best-fitting mass injection rate are consistent with their expected values. The stagnation point is at r st <~ 1'', so that most of the gas, including the gas at a Bondi radius rB = 2''-4'', outflows from the region. We put an upper limit on the accretion rate at 2 10-3 M ? yr-1. We find a shallow density profile nvpropr -? with ? ? 1 over a large dynamic range. This density profile is determined in the feeding region 0.''5-10'' 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 <~ 1'', and (4) the outflow at r >~ 1''. The gas temperature is close to the virial temperature Tv at any radius.

Shcherbakov, Roman V.; Wong, Ka-Wah; Irwin, Jimmy A.; Reynolds, Christopher S.

2014-02-01

308

Effects of High-Energy Particles on Accretion Flows onto a Supermassive Black Hole  

E-print Network

We study effects of high-energy particles on the accretion flows onto a supermassive black hole and luminosities of escaping particles such as protons, neutrons, gamma-rays, and neutrinos. We formulate a one-dimensional model of the two-component accretion flow consisting of thermal particles and high-energy particles, supposing that some fraction of the released energy is converted to the acceleration of the high-energy particles. The thermal component is governed by fluid dynamics while the high-energy particles obey the moment equations of the diffusion-convection equation. By solving the time evolution of these equations, we obtain advection dominated flows as the steady state solutions. Effects of the high-energy particles on the flow structures turn out to be small even if the pressure of the high-energy particles dominates over the thermal pressure. For a model in which the escaping protons take away almost all the released energy, the high-energy particles have large influence enough to make the flow ...

Kimura, Shigeo S; Takahara, Fumio

2014-01-01

309

Parallel-channel flow instabilities and active control schemes in two-phase microchannel heat exchanger systems  

Microsoft Academic Search

Parallel-channel flow mal-distribution and pressure-drop flow oscillations are two of the most severe dynamic instabilities for boiling flow especially in microchannel systems. This paper presents a framework for the transient analysis and active control of microchannel flow instabilities at a system-level view. A lumped two-phase flow system model is derived from the momentum balance equation to capture the characteristics of

TieJun Zhang; John T. Wen; Agung Julius; He Bai; Y. Peles; M. K. Jensen

2010-01-01

310

Measurement of the turbulent kinetic energy budget of a planar wake flow in pressure gradients  

Microsoft Academic Search

Turbulent kinetic energy (TKE) budget measurements were conducted for a symmetric turbulent planar wake flow subjected to constant zero, favorable, and adverse pressure gradients. The purpose of this study is to clarify the flow physics issues underlying the demonstrated influence of pressure gradient on wake development, and provide experimental support for turbulence modeling. To ensure the reliability of these notoriously

Xiaofeng Liu; Flint O. Thomas

2004-01-01

311

The dislocation distribution, flow stress, and stored energy in cold-worked polycrystalline silver  

Microsoft Academic Search

Distribution and densities of dislocations, determined by electron transmission microscopy, flow stress and stored energy measurements (by microcalorimetry) on cold-worked polycrystalline silver are correlated with each other, The dislocations are arranged in dense networks forming the boundaries of an otherwise relatively dislocation-free cell structure. The flow stress is explained quantitatively in terms of the forest intersection mechanism at the boundaries.

J. E. Bailey; P. B. Hirsch

1960-01-01

312

CHARACTERISTICS OF FAR FIELD AND ENERGY FLOW DUE TO A MOVING RADIATING SOURCE IN VARIOUS MEDIA  

E-print Network

CHARACTERISTICS OF FAR FIELD AND ENERGY FLOW DUE TO A MOVING RADIATING SOURCE IN VARIOUS MEDIA FIELD AND ENERGV FLOW DUE TO A MOVING RADIATING SOURCE IN VARIOUS MEDIA CONTENTS Acknowledgement. Abst.1 Definit.ion and physical meaning 3.2 Examples of DWS's 3.2.1 vacuum 3.2.2 isot.ropic non-dispersive media

Ng, Chung-Sang

313

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

NASA Astrophysics Data System (ADS)

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 to allow for realistic determination of lava surface temperatures from Earth orbit. This paper presents results obtained from the analysis of active lava flows using hyperspectral data acquired by NASA's Earth Observing-1 Hyperion imaging spectrometer. The contiguous nature of the measured radiance spectrum in the 0.4-2.5 micron region means that, although sensor saturation most certainly occurs, unsaturated radiance data are always available from even the hottest, and most radiant, active lava flow surfaces. The increased number of wavebands available allows for the assumption of more complex flow surface temperature distributions in the radiance-to-temperature inversion processes. The technique is illustrated by using a hyperspectral image of the active lava lake at Erta Ale volcano, Ethiopia, a well characterized calibration target. We then go on to demonstrate how this approach can be used to constrain the surface cooling rate of an active lava flow at Mount Etna, Sicily, using three images acquired during a four day period in September 2004. The cooling rate of the active channel as determined from space falls within the limits commonly assumed in numerical lava flow models. The results provide insights into the temperature-radiance mixture modeling problem that will aid in the analysis of data acquired by future hyperspectral remote sensing missions, such as NASA's proposed HyspIRI mission.

Wright, Robert; Garbeil, Harold

2010-05-01

314

Active Control of Flow Separation on a High-Lift System with Slotted Flap at High Reynolds Number  

NASA Technical Reports Server (NTRS)

The NASA Energy Efficient Transport (EET) airfoil was tested at NASA Langley's Low- Turbulence Pressure Tunnel (LTPT) to assess the effectiveness of distributed Active Flow Control (AFC) concepts on a high-lift system at flight scale Reynolds numbers for a medium-sized transport. The test results indicate presence of strong Reynolds number effects on the high-lift system with the AFC operational, implying the importance of flight-scale testing for implementation of such systems during design of future flight vehicles with AFC. This paper describes the wind tunnel test results obtained at the LTPT for the EET high-lift system for various AFC concepts examined on this airfoil.

Khodadoust, Abdollah; Washburn, Anthony

2007-01-01

315

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

E-print Network

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(110) km scales obtained ...

Nikurashin, Maxim

316

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

E-print Network

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...

Chen, Y.; Zhang, Z.

2006-01-01

317

Goal orientation, motivational climate, and dispositional flow of high school students engaged in extracurricular physical activity.  

PubMed

The purpose of this study was to examine the role of goal orientation, motivational climate, and dispositional flow in physical education lessons on extracurricular involvement in physical activity. Questionnaires were administered to 1,103 (792 athletes; 311 nonathletes) secondary school students (M age = 14.3 yr., SD = 0.7). Analysis showed significant mean differences between groups on goal orientation and dispositional flow in physical education lessons, but none for perception of motivational climate. These findings suggest that dispositional variables are related to extracurricular involvement in physical activity. PMID:16671603

Cervell, Eduardo M; Moreno, Juan A; Villodre, Nestor Alonso; Iglesias, Damin

2006-02-01

318

Fluid flow and heat convection studies for actively cooled airframes  

NASA Technical Reports Server (NTRS)

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.

Mills, A. F.

1993-01-01

319

Intensification of mixing of parallel compressible flows using a localized pulse-periodic energy supply  

NASA Astrophysics Data System (ADS)

The possibility of intensification of the mixing of supersonic and subsonic low-density gas jets that interact with an oblique shock with an ambient cocurrent supersonic flow using a localized pulse-periodic energy supply is demonstrated by means of numerical simulation. It is shown how an energy source located in front of the shock at the jet axis and also in an external flow affects the generation of large-scale vortex structures that favor the mixing process intensification.

Zheltovodov, A. A.; Pimonov, E. A.

2013-11-01

320

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

E-print Network

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.

B. Alver; for the PHOBOS Collaboration

2006-10-24

321

System size, energy, pseudorapidity, and centrality dependence of elliptic flow.  

PubMed

This Letter 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. 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. PMID:17677957

Alver, B; Back, B B; Baker, M D; Ballintijn, M; Barton, D S; Betts, R R; Bickley, A A; Bindel, R; Busza, W; Carroll, A; Chai, Z; Chetluru, V; Decowski, M P; Garca, E; Gburek, T; George, N; Gulbrandsen, K; Halliwell, C; Hamblen, J; Harnarine, I; Hauer, M; Henderson, C; Hofman, D J; Hollis, R S; Ho?y?ski, R; Holzman, B; Iordanova, A; Johnson, E; Kane, J L; Khan, N; Kulinich, P; Kuo, C M; Li, W; Lin, W T; Loizides, C; Manly, S; Mignerey, A C; Nouicer, R; Olszewski, A; Pak, R; Reed, C; Richardson, E; Roland, C; Roland, G; Sagerer, J; Seals, H; Sedykh, I; Smith, C E; Stankiewicz, M A; Steinberg, P; Stephans, G S F; Sukhanov, A; Szostak, A; Tonjes, M B; Trzupek, A; Vale, C; van Nieuwenhuizen, G J; Vaurynovich, S S; Verdier, R; Veres, G I; Walters, P; Wenger, E; Willhelm, D; Wolfs, F L H; Wosiek, B; Wo?niak, K; Wyngaardt, S; Wys?ouch, B

2007-06-15

322

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

NASA Astrophysics Data System (ADS)

This Letter 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. 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.

Alver, B.; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Chetluru, V.; Decowski, M. P.; Garca, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Harnarine, I.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Ho?y?ski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Richardson, E.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Szostak, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Walters, P.; Wenger, E.; Willhelm, D.; Wolfs, F. L. H.; Wosiek, B.; Wo?niak, K.; Wyngaardt, S.; Wys?ouch, B.

2007-06-01

323

Distributed Energy Communications & Controls, Lab Activities - Summary  

SciTech Connect

The purpose is to develop controls for inverter-based renewable and non-renewable distributed energy systems to provide local voltage, power and power quality support for loads and the power grid. The objectives are to (1) develop adaptive controls for inverter-based distributed energy (DE) systems when there are multiple inverters on the same feeder and (2) determine the impact of high penetration high seasonal energy efficiency ratio (SEER) air conditioning (A/C) units on power systems during sub-transmission faults which can result in an A/C compressor motor stall and assess how inverter-based DE can help to mitigate the stall event. The Distributed Energy Communications & Controls Laboratory (DECC) is a unique facility for studying dynamic voltage, active power (P), non-active power (Q) and power factor control from inverter-based renewable distributed energy (DE) resources. Conventionally, inverter-based DE systems have been designed to provide constant, close to unity power factor and thus not provide any voltage support. The DECC Lab interfaces with the ORNL campus distribution system to provide actual power system testing of the controls approach. Using mathematical software tools and the DECC Lab environment, we are developing and testing local, autonomous and adaptive controls for local voltage control and P & Q control for inverter-based DE. We successfully tested our active and non-active power (P,Q) controls at the DECC laboratory along with voltage regulation controls. The new PQ control along with current limiter controls has been tested on our existing inverter test system. We have tested both non-adaptive and adaptive control modes for the PQ control. We have completed several technical papers on the approaches and results. Electric power distribution systems are experiencing outages due to a phenomenon known as fault induced delayed voltage recovery (FIDVR) due to air conditioning (A/C) compressor motor stall. Local voltage collapse from FIDVR is occurring in part because modern air-conditioner and heat pump compressor motors are much more susceptible to stalling during a voltage sag or dip than older motors. These motors can stall in less than three cycles (0.05 s) when a fault, for example, on the sub-transmission system, causes voltage on the distribution system to sag to 70% or less of nominal. We completed a new test system for A/C compressor motor stall testing at the DECC Lab. The A/C Stall test system is being used to characterize when and how compressor motors stall under low voltage and high compressor pressure conditions. However, instead of using air conditioners, we are using high efficiency heat pumps. We have gathered A/C stall characterization data for both sustained and momentary voltage sags of the test heat pump. At low enough voltage, the heat pump stalls (compressor motor stops and draws 5-6 times normal current in trying to restart) due to low inertia and low torque of the motor. For the momentary sag, we are using a fast acting contactor/switch to quickly switch from nominal to the sagged voltage in cycles.

Rizy, D Tom [ORNL

2010-01-01

324

Joint moment control of mechanical energy flow during normal gait  

Microsoft Academic Search

The study purpose was to estimate the ability of joint moments to transfer mechanical energy through the leg and trunk during gait. A segmental power analysis of five healthy adult subjects revealed that internal joint extensor moments removed energy from the leg and added energy to the trunk, while flexor moments and gravity produced the opposite effects. The only exception

Karen Lohmann Siegel; Thomas M Kepple; Steven J Stanhope

2004-01-01

325

Cooling rate of an active Hawaiian lava flow from nighttime spectroradiometer measurements  

NASA Technical Reports Server (NTRS)

A narrow-band spectroradiometer has been used to make nighttime measurements of the Phase 50 eruption of Pu'u O'o, on the East Rift Zone of Kilauea Volcano, Hawaii. On February 19, 1992, a GER spectroradiometer was used to determine the cooling rate of an active lava flow. This instrument collects 12-bit data between 0.35 to 3.0 microns at a spectral resolution of 1-5 nm. Thirteen spectra of a single area on a pahoehoe flow field were collected over a 59 minute period (21:27-22:26 HST) from which the cooling of the lava surface has been investigated. A two-component thermal mixing model (Flynn, 1992) applied to data for the flow immediately on emplacement gave a best-fit crustal temperature of 768 C, a hot component at 1150 C, and a hot radiating area of 3.6 percent of the total area. Over a 52-minute period (within the time interval between flow resurfacings) the lava flow crust cooled by 358 to 410 C at a rate that was as high as 15 C/min. The observations have significance both for satellite observations of active volcanoes and for numerical models of the cooling of lava flows during their emplacement.

Flynn, Luke P.; Mouginis-Mark, Peter J.

1992-01-01

326

A Helioseismic Survey to Investigate Relationships between Subsurface Flows beneath Large Active Regions and Solar Flares  

NASA Astrophysics Data System (ADS)

A survey of the subsurface flow properties of about 120 of the largest active regions, determined from the application of helioseismic holography to Dopplergrams obtained with the HMI instrument onboard the Solar Dynamics Observatory, is being carried out. The overriding goal is to characterize differences in the subsurface flows between active regions associated with eruptive flares and the flows observed in relatively quiescent regions. Applications to flare forecasting comprise only one part of this investigation, since the potential response of the subsurface environment to eruptive events during and after their occurrence is also of scientific interest. Other priorities include understanding the limitations of the helioseismic methods, identifying and correcting systematic effects, and validating the reliability of the measurements using artificial data. While inversions to determine the variation with depth of subsurface flows are planned, preliminary results will be discussed which make use of proxies for near-surface depth-integrated properties, including the horizontal component of the flow divergence and the vertical component of the flow vorticity.This work is supported by the Solar Terrestrial Program of the National Science Foundation, through grant AGS-1127327, and by the National Oceanic and Atmospheric Administration SBIR program.

Braun, Douglas; Leka, K D.; Barnes, Graham

2014-06-01

327

Active ultrasonic cross-correlation flowmeters for mixed-phase pipe flows  

NASA Astrophysics Data System (ADS)

Two ultrasonic flowmeters which employ the active cross-correlation technique and use a simple clamp-on transducer arrangement are discussed. The flowmeter for solid/liquid flows was tested over a wide range of coal concentration in water and oil. The measured velocity based on the peak position of the cross-correlation function is consistently higher by about 15% than the average velocity measured by flow diversion. The origin of the difference results mainly from the flow velocity profiles and the transit-time probability distribution. The flowmeter that can measure particle velocity in a solid/gas flow requires acoustic decoupling arrangement between two sensing stations. The measured velocity is mainly associated with the particles near the wall. Performance of both flowmeters is presented.

Sheen, S. H.; Raptis, A. C.

328

Scheduling for Weighted Flow Time and Energy with Rejection Penalty  

E-print Network

This paper revisits the online problem of flow-time scheduling on a single processor when jobs can. Specifically, jobs are released online with arbitrary sizes, weights and penalties. Consider a schedule which.K. Lee 393 Assuming jobs have uniform penalty and unit weight, Bansal et al. [4] gave an online algorithm

Paris-Sud XI, Université de

329

Scheduling for Weighted Flow Time and Energy with Rejection Penalty  

E-print Network

This paper revisits the online problem of flow-time scheduling on a single processor when jobs can. Specifically, jobs are released online with arbitrary sizes, weights and penalties. Consider a schedule which Penalty Assuming jobs have uniform penalty and unit weight, Bansal et al. [4] gave an online algorithm

Lam, Tak-Wah

330

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

E-print Network

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.

Lawrence E. Thomas

2012-04-29

331

ANTI-PARALLEL EUV FLOWS OBSERVED ALONG ACTIVE REGION FILAMENT THREADS WITH HI-C  

SciTech Connect

Plasma flows within prominences/filaments have been observed for many years and hold valuable clues concerning the mass and energy balance within these structures. Previous observations of these flows primarily come from H? and cool extreme-ultraviolet (EUV) lines (e.g., 304 ) where estimates of the size of the prominence threads has been limited by the resolution of the available instrumentation. Evidence of 'counter-steaming' flows has previously been inferred from these cool plasma observations, but now, for the first time, these flows have been directly imaged along fundamental filament threads within the million degree corona (at 193 ). In this work, we present observations of an AR filament observed with the High-resolution Coronal Imager (Hi-C) that exhibits anti-parallel flows along adjacent filament threads. Complementary data from the Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager are presented. The ultra-high spatial and temporal resolution of Hi-C allow the anti-parallel flow velocities to be measured (70-80 km s{sup 1}) and gives an indication of the resolvable thickness of the individual strands (0.''8 0.''1). The temperature of the plasma flows was estimated to be log T (K) = 5.45 0.10 using Emission Measure loci analysis. We find that SDO/AIA cannot clearly observe these anti-parallel flows or measure their velocity or thread width due to its larger pixel size. We suggest that anti-parallel/counter-streaming flows are likely commonplace within all filaments and are currently not observed in EUV due to current instrument spatial resolution.

Alexander, Caroline E.; Walsh, Robert W.; Rgnier, Stphane [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom)] [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Cirtain, Jonathan; Winebarger, Amy R. [NASA Marshall Space Flight Center, VP 62, Huntsville, AL 35812 (United States)] [NASA Marshall Space Flight Center, VP 62, Huntsville, AL 35812 (United States); Golub, Leon; Korreck, Kelly; Weber, Mark [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kobayashi, Ken [Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35805 (United States)] [Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Platt, Simon; Mitchell, Nick [School of Computing, Engineering and Physical Sciences, University of Central Lancashire, Preston PR1 2HE (United Kingdom)] [School of Computing, Engineering and Physical Sciences, University of Central Lancashire, Preston PR1 2HE (United Kingdom); DePontieu, Bart; Title, Alan [Lockheed Martin Solar and Astrophysics Lab, 3251 Hanover Street, Org. ADBS, Bldg. 252, Palo Alto, CA (United States)] [Lockheed Martin Solar and Astrophysics Lab, 3251 Hanover Street, Org. ADBS, Bldg. 252, Palo Alto, CA (United States); DeForest, Craig [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)] [Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States); Kuzin, Sergey [P.N. Lebedev Physical institute of the Russian Academy of Sciences, Leninskii prospekt, 53, 119991 Moscow (Russian Federation)] [P.N. Lebedev Physical institute of the Russian Academy of Sciences, Leninskii prospekt, 53, 119991 Moscow (Russian Federation)

2013-09-20

332

Mass, momentum and energy flow from an MPD accelerator. Ph.D. Thesis  

NASA Technical Reports Server (NTRS)

The mass, momentum, and energy flows are measured over a current range of 8 to 50 kA and inlet mass flows of 2 to 36q/sec of argon. The momentum flux profile indicates that the accelerator produces a uniform, 2-inch diameter axial jet at the anode which expands into a Gaussian profile at an axial station 11 inches from the anode. The electromagnetic component of the thrust is found to follow the familiar quadratic dependence on arc current, while a more complex empirical relation is needed to correlate the gasdynamic contribution with the current and mass flow rate. Using available time-of-flight velocity profiles at a current of 16 kA and a mass flow of 5.9 g/sec, calculated flux profiles of mass and kinetic energy exhibit a tendency for some fraction of the inlet mass flow to leak out at a low velocity around the central high velocity core.

Cory, J. S.

1971-01-01

333

This paper presents an investigation of power and energy transduction in piezoelectric wafer active sensors (PWAS) on isotropic structure for structural health  

E-print Network

is sensed by active interrogation of the structure with elastic waves. The power and energy flow in active1 ABSTRACT This paper presents an investigation of power and energy transduction in piezoelectric wafer active sensors (PWAS) on isotropic structure for structural health monitoring (SHM). After

Giurgiutiu, Victor

334

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

E-print Network

Femtosecond chemical activation of reactions at very high thermal energies, much above the bond energyFemtosecond Chemically Activated Reactions: Concept of Nonstatistical Activation at High Thermal Energies Sang Kyu Kim, Ju Guo, J. Spencer Baskin, and Ahmed H. Zewail* Arthur Amos Noyes Chemical Physics

Kim, Sang Kyu

335

Local expansion flows of galaxies: quantifying acceleration effect of dark energy  

NASA Astrophysics Data System (ADS)

The nearest expansion flow of galaxies observed around the Local group is studied as an archetypical example of the newly discovered local expansion flows around groups and clusters of galaxies in the nearby Universe. The flow is accelerating due to the antigravity produced by the universal dark energy background. We introduce a new acceleration measure of the flow which is the dimensionless ``acceleration parameter" Q (x) = x - x-2 depending on the normalized distance x only. The parameter is zero at the zero-gravity distance x = 1, and Q(x) ? x, when x ? 1. At the distance x = 3, the parameter Q = 2.9. Since the expansion flows have a self-similar structure in normalized variables, we expect that the result is valid as well for all the other expansion flows around groups and clusters of galaxies on the spatial scales from 1 to 10 Mpc everywhere in the Universe.

Chernin, A. D.; Teerikorpi, P.

2013-08-01

336

Understanding patrons' participation in activities at entertainment malls : A study in flow  

Microsoft Academic Search

Purpose This paper aims to apply concepts from flow paradigm to examine factors contributing to participation in entertainment and shopping activities at, and future patronage intent toward, entertainment shopping malls. Design\\/methodology\\/approach Data were collected from 342 consumers via mall intercepts conducted at two major entertainment shopping malls located in major metropolitan areas in the US states of Arizona

Sherry L. Lotz; Mary Ann Eastlick; Anubha Mishra; Soyeon Shim

2010-01-01

337

Thermal radiance observations of an active lava flow during the June 1984 eruption of Mount Etna  

Microsoft Academic Search

The thermal budget of an active lava flow observed on 20 June 1984 from the Southeast crater of Mount Etna, Sicily, Italy, was analyzed from data taken by the Landsat Thematic Mapper. The Thematic Mapper images constitute one of the few satellite data sets of sufficient spatial and spectral resolution to allow calibrated measurements on the distribution and intensity of

David C. Pieri; Lori S. Glaze; Michael J. Abrams

1990-01-01

338

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

E-print Network

'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

Rose, William I.

339

Sponsored Programs Activity High Level Flow Chart OSP = Office of Sponsored Programs (PreAward)  

E-print Network

Sponsored Programs Activity High Level Flow Chart 3/3/09 OSP = Office of Sponsored Programs (PreAward) OSP-GA = Office of Sponsored Programs Grants Administrator OSP-DS = OSP's Database Specialist GCA Accepted B6 OSP-GA Negotiates Resolves Conflicts B5 OSP-GA Reviews Award and Proposal on File B4 Sponsor

Duchowski, Andrew T.

340

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

ERIC Educational Resources Information Center

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

Roelofs, Ardi

2008-01-01

341

Active control of flow-induced noise transmitted through aircraft sidewalls  

Microsoft Academic Search

In this paper, the theory and the results are presented of a study concerned with the active control of sound transmitted through aircraft sidewalls when excited by a Turbulent Boundary Layer. The motivation for this study is the control within an aircraft cabin of the flow-induced noise due to wall-pressure fluctuations over the fuselage. First, a theoretical model accounting for

Cedric Maury; Paolo Gardonio; Stephen J. Elliott

2003-01-01

342

An active region model for capturing fractal flow patterns in unsaturated soils: Model development  

Microsoft Academic Search

Preferential flow commonly observed in unsaturated soils allows rapid movement of solute from the soil surface or vadose zone to the groundwater, bypassing a significant volume of unsaturated soil and increasing the risk of groundwater contamination. A variety of evidence indicates that complex preferential patterns observed from fields are fractals. In this study, we developed a relatively simple active region

Hui-Hai Liu; R. Zhang; Gudmundur S. Bodvarsson

2005-01-01

343

Evaluation of active flow control applied to wind turbine blade section  

Microsoft Academic Search

A feasibility study for implementing active flow control (AFC) methods to improve the performance of wind turbines was performed. The experimental effort investigated the impact of zero-mass-flux (ZMF) piezofluidic actuators attempting to control boundary layer separation from thick airfoils that are suitable for wind turbine rotor blades. It was demonstrated that the ZMF actuators can replace passive vortex generators that

O. Stalnov; A. Kribus; A. Seifert

2010-01-01

344

Enabling Active Flow Manipulation in Silicon-Based Network Forwarding Engines  

Microsoft Academic Search

A significant challenge in today's Internet is the a bility to efficiently incorporate c ustomizable network intelligences in commercial high p erformance network devices. This paper tackles the c hallenge by introducing the Active Flow Manipulation (AFM) mechanism, a key enabling technology of the programmable networking platform Openet. AFM enhances the c ontrol i ntelligence of network devices through programmability.

Tal Lavian; Phil Wang; Franco Travostino; Siva Subramanian; Ramesh Durairaj; Doan B. Hoang; Vijak Sethaput; David E. Culler

2002-01-01

345

Microgrid central fuzzy controller for active and reactive power flow using instantaneous power measurements  

Microsoft Academic Search

Microgrids have become in an important research field in power electronics and play a key role in the Distributed Generation (DG) concept. In this paper, a fuzzy logic controller is proposed for Low Voltage (LV) microgrids, based on Voltage Source Converter (VSC) technology and DG. The control strat- egy designed aims the active and reactive power flow with the grid

H. R. Chamorro; G. Ramos

2011-01-01

346

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...

347

Force interaction of high pressure glow discharge with fluid flow for active separation control  

E-print Network

discharge DBD at high pressure to inhibit phenomena such as stall on airfoils, thus improving their liftForce interaction of high pressure glow discharge with fluid flow for active separation control modeling to lift limitations in the current understanding of the actuation mechanism. The present effort

Roy, Subrata

348

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

E-print Network

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

Banbara, Mutsunori

349

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

Microsoft Academic Search

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

Robert Wright; Harold Garbeil

2010-01-01

350

Active Gaze Control Improves Optic Flow-Based Segmentation and Steering  

Microsoft Academic Search

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

Florian Raudies; Ennio Mingolla; Heiko Neumann

2012-01-01

351

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

ERIC Educational Resources Information Center

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

Roelofs, Ardi; Dijkstra, Ton; Gerakaki, Svetlana

2013-01-01

352

Energy transport by kinetic-scale electromagnetic waves in fast plasma sheet flows  

NASA Astrophysics Data System (ADS)

We report observations from the THEMIS spacecraft characterizing the nature and importance of low frequency electromagnetic fluctuations on kinetic scales embedded within fast flows in the Earth's plasma sheet. A consideration of wave property variations with frequency and flow speed suggest that for spacecraft frame frequencies satisfying |vf|/i ? sc ? 100|vf|/i (or 0.2 ? fsc ? 20 Hz) these fluctuations can generally be described as kinetic Alfvn waves. Here vf is the flow speed, i the ion gyroradius, and sc and fsc are the angular and cyclical frequencies respectively in the spacecraft frame. The statistics of energy transport via Poynting flux (S) in these fluctuations and ion energy flux () in the flow follow log normal distributions with mean values of = 101.1 0.7 and = 102.4 0.4 mW/m2 respectively where the values are mapped to a reference magnetic field at 100 km altitude. Here the indices following correspond to one standard deviation. We find that = 10-1.3 0.7 or that kinetic Alfvn waves on average transport 5% of the total energy transport in the flow but note that the values larger than 25% are within one standard deviation of the mean. Our observations show that these waves are continually radiated outward from the flow toward the auroral oval, low latitude boundary layer or lobes and that over several Earth-radii the integrated energy loss from the flow channel can be comparable to the total energy content of the flow itself. We find that this plasma sheet energy loss process is particularly effective within |XGSE| ? 15 RE.

Chaston, C. C.; Bonnell, J. W.; Clausen, L.; Angelopoulos, V.

2012-09-01

353

Portable Liquid Flow Metering for Energy Conservation Programs  

E-print Network

":t';, - -:.:: ~.? - , LEI'OXY I?SI. I FR.Q!!!.2'IEW Figure 1 - Doppler Flowmeter Doppler flowmeters transmit a continuous ultrasonic beam through the pipe wall into the stream. Reflected ultrasonic waves from the entrained bubbles... 215 Sensing Lines, fittings 250 Flanges (S.S.) 250 Remote display 215 Labor (3 men, 10 hrs @ $30/hr) 900 Total installed cost $2,890 Annual Operating cost to make up press. loss 298 $3,188 4" ULTRASONIC Multipipe Portable Flow $3...

Miles, F. J.

1982-01-01

354

Energy Conservation Teaching Activities for Home Economics Classrooms.  

ERIC Educational Resources Information Center

This collection of home economics activities is intended to meet the special needs of home economics teachers who wish to include energy education activities in their curricula. The 45 activities can be used as presented, or can be modified to individual needs or local conditions. Each activity includes: (1) title, (2) objective, (3) activity

Jedlicka, Ella, Ed.

355

Simulation of activation free energies in molecular systems  

Microsoft Academic Search

A method is presented for determining activation free energies in complex molecular systems. The method relies on knowledge of the minimum energy path and bases the activation free energy calculation on moving along this path from a minimum to a saddle point. Use is made of a local reaction coordinate which describes the advance of the reaction in each segment

Eyal Neria; Stefan Fischer; Martin Karplus

1996-01-01

356

Sample Energy Conservation Education Activities for Elementary School Students.  

ERIC Educational Resources Information Center

The booklet contains learning activities for introducing energy and conservation concepts into the existing elementary school curriculum. The activities were developed by Palm Beach County teachers during a one-week workshop. A framework of ideas is divided into three functional categories: universe of energy, living systems and energy, and social

Allen, Rodney F., Ed.; LaHart, David E., Ed.

357

The Role of Preflow Topography on the Surface Morphology and Thermal Evolution of Actively Inflating Basaltic Lava Flows  

Microsoft Academic Search

In an attempt to test hypotheses regarding the role of underlying topography on lava flow surface morphology, we acquired pre-, syn- and post-flow topographic data from active pahoehoe flows advancing over hummocky topography at Kilauea volcano, Hawaii. Kilauea volcano (HI) is in a state of eruption that has persisted almost without interruption for over 20 years, and is in a

S. W. Anderson; M. S. Ramsey; D. A. Crown; J. M. Byrnes; E. R. Stofan

2005-01-01

358

Generalization and extension of the law of acoustic energy conservation in a nonuniform flow  

NASA Technical Reports Server (NTRS)

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.

Myers, M. K.

1986-01-01

359

Energy Harvesting from Fluid Flow in Water Pipelines for Smart Metering Applications  

NASA Astrophysics Data System (ADS)

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.

Hoffmann, D.; Willmann, A.; Gpfert, R.; Becker, P.; Folkmer, B.; Manoli, Y.

2013-12-01

360

Energy flow through an Apatani village ecosystem of Arunachal Pradesh in northeast India  

Microsoft Academic Search

The energy flow through the ecosystem of a typical Apatani village in Arunachal Pradesh in northeastern India was studied. The energy and economic efficiency of the rice agro-ecosystem of this region is exceptionally high, and rice is exported after meeting local needs. The cropping pattern varies depending upon the amount of organic residues recycled into the system. Where recycling is

Anil Kumar I; P. S. Ramakrishnan

1990-01-01

361

Leaf litter processing and energy flow through macroinvertebrates in a woodland pond (Switzerland)  

Microsoft Academic Search

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,

B. Oertli

1993-01-01

362

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...

363

Computational Science Technical Note CSTN-050 Energy Flow and Conservation in an Artificial Life Agent Model  

E-print Network

in an Artificial Life Agent Model}, booktitle = {Proc. 2008 International Conference on Artificial Intelligence0 Computational Science Technical Note CSTN-050 Energy Flow and Conservation in an Artificial Life-based artificial life models are commonly constructed without a strict energy conservation rule. We report

Hawick, Ken

364

When Do Variable Flow Fume Hoods Save Energy? Implications for lab design and behavior  

E-print Network

local climate, energy rates, efficiency to calc $/cfm & load costs http://fumehoodcalculator.lbl.gov/index.php #12;National Impact of Fume Hoods � Mills and Sartor 2006 paper � Significant energy use in US: ~750 maintains constant face velocity, varies flow rate � High capital cost but lower operating costs

Hutyra, Lucy R.

365

Are preferential flow paths perpetuated by microbial activity in the soil matrix? A review  

NASA Astrophysics Data System (ADS)

SummaryRecently, the interactions between soil structure and microbes have been associated with water transport, retention and preferential or column flow development. Of particular significance is the potential impact of microbial extracellular polymeric substances (EPS) on soil porosity (i.e., hydraulic conductivity reduction or bioclogging) and of exudates from biota, including bacteria, fungi, roots and earthworms on the degree of soil water repellency. These structural and surface property changes create points of wetting instability, which under certain infiltrating conditions can often result in the formation of persistent preferential flow paths. Moreover, distinct differences in physical and chemical properties between regions of water flow (preferential flow paths) and no-flow (soil matrix) provide a unique set of environmental living conditions for adaptable microorganisms to exist. In this review, special consideration is given to: (1) the functional significance of microbial activity in the host porous medium in terms of feedback mechanisms instigated by irregular water availability and (2) the related physical and chemical conditions that force the organization and formation of unique microbial habitats in unsaturated soils that prompt and potentially perpetuate the formation of preferential flow paths in the vadose zone.

Morales, Vernica L.; Parlange, J.-Yves; Steenhuis, Tammo S.

2010-10-01

366

Numerical Modeling and Simulations on Electo-Active Polymer Flow Control  

NASA Astrophysics Data System (ADS)

The primary focus of this study is to identify the effects of vibrating Electro-Active Polymer (EAP) flow control on the flow field, specifically within the boundary layer. The EAPs represent a light-weight and adaptable flow control solution for micro-air vehicles (MAV). In this study, the interaction of the flow field over a flat plate and NACA 0009 airfoil are modeled at a Reynolds number of 20,000 using an Arbitrary Lagrangian Eulerian finite element formulation. In the simulations, the EAP vibration is prescribed based on the measurements from the experiments. The results show the EAPs do alter the boundary layer flow field and the size of the separation bubble. Three different diameter EAPs are examined on the flat plate model: 6mm, 9mm, and 12mm. Each is evaluated at different vibrational frequencies and maximum amplitudes. The performance of the EAPs on the NACA 0009 model are also evaluated while the airfoil is experiencing a pitching motion and gusts. Both instantaneous and time averaged flow fields are analyzed. The results from the numerical simulations are compared to baseline CFD simulations and wind tunnel results.

Weddle, Andrew; Amitay, Michael; Zhang, Lucy

2011-11-01

367

Energy Conservation Activity Packet, Grade 6. Revised Edition.  

ERIC Educational Resources Information Center

This activity notebook for grade 6 is one of a series 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 grade six. The packet is divided into two parts and provides the teacher with background information, concepts and

Pohlman, Betty; And Others

368

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

ERIC Educational Resources Information 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

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

369

Energy Conservation Activity Packet, Grade 5. Revised Edition.  

ERIC Educational Resources Information Center

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

Pohlman, Betty; And Others

370

TRITON-3HE Relative and Differential Flows and the High Density Behavior of Nuclear Symmetry Energy  

NASA Astrophysics Data System (ADS)

Using a transport model coupled with a phase-space coalescence after-burner we study the triton-3He relative and differential transverse flows in semi-central 132Sn + 124Sn reactions at a beam energy of 400 MeV/nucleon. We find that the triton-3He pairs carry interesting information about the density dependence of the nuclear symmetry energy. The t-3He relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy.

Yong, Gao-Chan; Li, Bao-An; Chen, Lie-Wen

371

Active Control of Flow around NACA 0015 Airfoil by Using DBD Plasma Actuator  

NASA Astrophysics Data System (ADS)

In this study, effect of plasma actuator on a flat plate and manipulation of flow separation on NACA0015 airfoil with plasma actuator at low Reynolds numbers were experimentally investigated. In the first section of the study, plasma actuator which consists of positive and grounded electrode couple and dielectric layer, located on a flat plate was actuated at different frequencies and peak to peak voltages in range of 3-5 kHz and 6-12 kV respectively. Theinduced air flow velocity on the surface of flat plate was measured by pitot tube at different locations behind the actuator. The influence of dielectricthickness and unsteady actuation with duty cycle was also examined. In the second section, the effect of plasma actuator on NACA0015 airfoil was studied atReynolds number 15000 and 30000. Four plasma actuators were placed at x/C = 0.1, 0.3, 0.5 and 0.9, and different electrode combinations were activated by sinusoidal signal. Flow visualizations were done when the attack angles were 0, 5, 10, 15 and 20. The results indicate that up to the 15 attack angle, the separated flow was reattached by plasma actuator at 12kV peak to peak voltage and 4 kHz frequency. However, 12 kVpp voltage was insufficient to reattach the flow at 20 angle of attack. The separated flow could be reattached by increasing the voltage up to 13 kV. Lift coefficient was also increased by the manipulated flow over the airfoil. Results showed that even high attack angles, the actuators can control the flow separation and prevent the airfoil from stall at low Reynolds numbers.

Akansu, Y. E.; Karakaya, F.; ?anl?soy, A.

2013-04-01

372

Surface free energy activated high-throughput cell sorting.  

PubMed

Cell sorting is an important screening process in microbiology, biotechnology, and clinical research. Existing methods are mainly based on single-cell analysis as in flow cytometric and microfluidic cell sorters. Here we report a label-free bulk method for sorting cells by differentiating their characteristic surface free energies (SFEs). We demonstrated the feasibility of this method by sorting model binary cell mixtures of various bacterial species, including Pseudomonas putida KT2440, Enterococcus faecalis ATCC 29212, Salmonella Typhimurium ATCC 14028, and Escherichia coli DH5?. This method can effectively separate 10(10) bacterial cells within 30 min. Individual bacterial species can be sorted with up to 96% efficiency, and the cell viability ratio can be as high as 99%. In addition to its capacity of sorting evenly mixed bacterial cells, we demonstrated the feasibility of this method in selecting and enriching cells of minor populations in the mixture (presenting at only 1% in quantity) to a purity as high as 99%. This SFE-activated method may be used as a stand-alone method for quickly sorting a large quantity of bacterial cells or as a prescreening tool for microbial discrimination. Given its advantages of label-free, high-throughput, low cost, and simplicity, this SFE-activated cell sorting method has potential in various applications of sorting cells and abiotic particles. PMID:25184988

Zhang, Xinru; Zhang, Qian; Yan, Tao; Jiang, Zeyi; Zhang, Xinxin; Zuo, Yi Y

2014-09-16

373

Reduction of vortex shedding intensity from a cylinder using semi-active flow control  

NASA Astrophysics Data System (ADS)

Experiments were performed in the open water channel at the Waterpower Laboratory, NTNU, Norway, with the aim of reducing vortex shedding intensity by semi-active flow control. The test rig consisted of a perforated steel tube lined by a rubber bellows. The holes (d/D=0.6) formed a line at the leading edge, one tube diameter apart. Two flow control modes were attainable; (1) lining being flush with the cylinder wall, and (2) pressurized lining creating leading edge bumps. Upstream flow conditions were monitored, and used as input for the control loop governing the pressure of the lining. A flat metal rod, onto which strain gauges were glued, was positioned in the wake. It was assumed that the motion of the rod corresponded to the velocity components normal to the main flow direction. Thus the motion of the rod described the vortex shedding from the tube. Strouhal numbers were found to be approximately 0.3. It was the assumption that the bumps would disrupt vortex formation and reduce the vortex intensity. Tests showed that the assumption was plausible, with observed intensity reductions of 15-30% for ReD [20000 to 50000]. Plots also appear to show a breakdown of organization in the wake when the tube is in activated mode. It was shown that semi-active control of vortex shedding behind a cylinder is achievable.

Ekanger, Jarle V.; Kjeldsen, Morten

2011-11-01

374

Renewable energy activities in Senegal: a review  

Microsoft Academic Search

Like many countries in Africa, Senegal is facing economical decline, energy crisis and serious desertification problem in rural areas. These issues could be removed if renewable energy is used as a primary source of energy in rural areas. What is required is a strategy to implement renewable energy technologies at large scale. The government and many non-governmental organisations (NGOs) have

I. Youm; J. Sarr; M. Sall; M. M. Kane

2000-01-01

375

Comparison of High-Energy Gas Flow Experiments  

Microsoft Academic Search

The results of three experiments which used Voitenko compressors to produce high-energy gas jets of Ne, O2, and CO2 are described here. Velocities of various components of the jets were obtained by monitoring the luminosity of the jets as they passed through evacuated outlet pipes. The slight velocity attenuation observed in these jets is briefly compared with other high-energy gas

H. D. Glennt; B. K. Crowley

1971-01-01

376

Transient radiative energy transfer in incompressible laminar flows  

NASA Technical Reports Server (NTRS)

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.

Tiwari, S. N.; Singh, D. J.

1987-01-01

377

Aircraft energy efficiency laminar flow control wing design study  

NASA Technical Reports Server (NTRS)

An engineering design study was performed in which laminar flow control (LFC) was integrated into the wing of a commercial passenger transport aircraft. A baseline aircraft configuration was selected and the wing geometry was defined. The LFC system, with suction slots, ducting, and suction pumps was integrated with the wing structure. The use of standard aluminum technology and advanced superplastic formed diffusion bonded titanium technology was evaluated. The results of the design study show that the LFC system can be integrated with the wing structure to provide a structurally and aerodynamically efficient wing for a commercial transport aircraft.

Bonner, T. F., Jr.; Pride, J. D., Jr.; Fernald, W. W.

1977-01-01

378

National Alliance of Clean Energy Incubator Activities - Final Technical Report  

SciTech Connect

Summary of activity related to development of the Alliance of Clean Energy Business Incubators and incubation services provided to the clean energy sector by the Advanced Technology Development Center at the Georgia Institute of Technology.

Chris Downing, P.E.

2004-12-14

379

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

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

380

Daily Activity Energy Expenditure and Mortality Among Older Adults  

Microsoft Academic Search

Context Exercise is associated with mortality benefits but simply expending energy through any activity in an individual's free-living environment may confer survival ad- vantages. Objective To determine whether free-living activity energy expenditure is associ- ated with all-cause mortality among older adults. Design, Setting, and Participants Free-living activity energy expenditure was assessed in 302 high-functioning, community-dwelling older adults (aged 70-82 years).

Todd M. Manini; James E. Everhart; Kushang V. Patel; Dale A. Schoeller; Lisa H. Colbert; Marjolein Visser; Frances Tylavsky; Douglas C. Bauer; Bret H. Goodpaster; Tamara B. Harris

2007-01-01

381

Phase transition model of water flow irradiated by high-energy laser in a chamber  

NASA Astrophysics Data System (ADS)

In the absorption chamber of a high-energy laser energy meter, water is directly used as an absorbing medium and the interaction of the high-power laser and the water flow can produce a variety of physical phenomena such as phase transitions. The unit difference method is adopted to deduce the phase transition model for water flow irradiated by a high-energy laser. In addition, the model is simulated and verified through experiments. Among them, the experimental verification uses the photographic method, shooting the distribution and the form of the air mass of water flow in different operating conditions, which are compared with the simulation results. The research shows that it is achievable to reduce the intensity of the phase transition by increasing the water flow, reducing the power intensity of the beam, shortening the distance the beam covers, reducing the initial water temperature or adopting a shorter wavelength laser. The study's results will provide the reference for the design of a water-direct-absorption-type high-energy laser energy meter as well as an analysis of the interaction processes of other similar high-power lasers and water flow.

Wei, Ji-Feng; Sun, Li-Qun; Zhang, Kai; Hu, Xiao-Yang

2014-07-01

382

[Influence of laser energy on measurement of unburned carbon in fly Ash particle flow].  

PubMed

The fly ash particle flow was produced by a screw feeder and then ablated by a pulse laser to create plasma. The emission spectra of fly ash were detected by laser-induced breakdown spectroscopy. The present paper focused on the influence of laser energy on the measurement of unburned carbon. Seven groups of pulse laser in the range of 40 to 130 mJ were used to ablate the fly ash particle flow. The results show that the carbon line intensity is increased linearly with the increases in laser energy, but the SNR of carbon line increases in the range of 40 to 90 mJ and then trends to saturation, while the elimination rate of false data decreases. In this experiment, laser energy ranging from 90 to 100 mJ can enhance the plasma emission signal and improve the true spectral data of fly ash particle flow. So laser energy has close correlations with the ablation of the particle flow and the carbon line intensity. Reasonable laser energy is good for the effective ablation of the fly ash particle flow to get plasma spectra signals with good SNR. PMID:25095448

Bai, Kai-Jie; Tian, Hao-Chen; Yao, Shun-Chun; Zhang, Bo; Shen, Yue-Liang; Xu, Qi-Sheng; Lu, Ji-Dong

2014-05-01

383

Preferential flow in connected soil structures and the principle of "maximum energy dissipation": A thermodynamic perspective  

NASA Astrophysics Data System (ADS)

"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.

Zehe, E.; Blume, T.; Bloeschl, G.

2009-04-01

384

Electronics Design for Dual Energy Gamma-Ray Multiphase Flow Meter  

NASA Astrophysics Data System (ADS)

There are two ways to design nuclear electronics for a dual energy ? ray multiphase flow meter. The advanced way is based on high speed A/D data acquisition and DSP digital signal processing, but it involves a complicated system structure and a huge data flow; the conventional way is based on the technique of photon pulse counter, which is complicated in electrical design, but simple in system structure due to its low data flow. Both systems are studied in the Multiphase Flow Laboratory, Institute of Mechanics, Chinese Academy of Sciences. In this paper, the instrumental designs on the technique of photon pulse counter will be mainly discussed, including the ? ray sensor's characteristics, signals of sensor, preamplifier, filter and shaping amplifier, DC base shift correcting circuit, narrow windows of energy spectroscopy, programmable pulse count acquisition system.

Li, Donghui; Wu, Yingxiang; Wang, Keren

2007-06-01

385

Nonlinear energy transfers and phase diagrams for geostrophically balanced rotating-stratified flows.  

PubMed

Equilibrium statistical mechanics tools have been developed to obtain indications about the natural tendencies of nonlinear energy transfers in two-dimensional and quasi-two-dimensional flows like rotating and stratified flows in geostrophic balance. In this article we consider a simple model of such flows with a nontrivial vertical structure, namely, two-layer quasigeostrophic flows, which remain amenable to analytical study. We obtain the statistical equilibria of the system in the case of a linear vorticity-stream function relation, build the corresponding phase diagram, and discuss the most probable outcome of nonlinear energy transfers, both on the horizontal and on the vertical, in the presence of stratification and rotation. PMID:24730938

Herbert, Corentin

2014-03-01

386

Energy and materials flows in the copper industry  

SciTech Connect

The copper industry comprises both the primary copper industry, which produces 99.9%-pure copper from copper ore, and the secondary copper industry, which salvages and recycles copper-containing scrap metal to extract pure copper or copper alloys. The United States uses about 2 million tons of copper annually, 60% of it for electrical applications. Demand is expected to increase less than 4% annually for the next 20 years. The primary copper industry is concentrated in the Southwest; Arizona produced 66% of the 1979 total ore output. Primary production uses about 170 x 10/sup 12/ Btu total energy annually (about 100 x 10/sup 6/ Btu/ton pure copper produced from ore). Mining and milling use about 60% of the total consumption, because low-grade ore (0.6% copper) is now being mined. Most copper is extracted by smelting sulfide ores, with concomitant production of sulfur dioxide. Clean air regulations will require smelters to reduce sulfur emissions, necessitating smelting process modifications that could also save 20 x 10/sup 12/ Btu (10 x 10/sup 6/ Btu/ton of copper) in smelting energy. Energy use in secondary copper production averages 20 x 10/sup 6/ Btu/ton of copper. If all copper products were recycled, instead of the 30% now salvaged, the energy conservation potential would be about one-half the total energy consumption of the primary copper industry.

Gaines, L.L.

1980-12-01

387

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

NASA Technical Reports Server (NTRS)

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.

Axdahl, Erik; Kumar, Ajay; Wilhite, Alan

2013-01-01

388

Satellite-Borne and Field-Based Hyperspectral Measurements of Active Lava Flows at Kilauea Volcano, Hawaii  

Microsoft Academic Search

A better understanding of the evolving surface thermal structure of active lava flow fields is possible with the synoptic view and high spatial resolution afforded by satellite-borne hyperspectral instruments such as the Hyperion sensor aboard Earth Observing-1. Hyperion data collected on March 21, 2001, over the active Kilauea flow field, allow us to examine the surface structure of each thermally

L. R. Geschwind; L. P. Flynn; A. J. Harris; S. Sahetapy-Engel

2002-01-01

389

Algebraic structure of general electromagnetic fields and energy flow  

SciTech Connect

Highlights: > Algebraic structure of general electromagnetic fields in stationary spacetime. > Eigenvalues and eigenvectors of the electomagnetic field tensor. > Energy-momentum in terms of eigenvectors and Killing vector. > Explicit form of reference frame with vanishing Poynting vector. > Application of formalism to Bessel beams. - Abstract: The algebraic structures of a general electromagnetic field and its energy-momentum tensor in a stationary space-time are analyzed. The explicit form of the reference frame in which the energy of the field appears at rest is obtained in terms of the eigenvectors of the electromagnetic tensor and the existing Killing vector. The case of a stationary electromagnetic field is also studied and a comparison is made with the standard short-wave approximation. The results can be applied to the general case of a structured light beams, in flat or curved spaces. Bessel beams are worked out as example.

Hacyan, Shahen, E-mail: hacyan@fisica.unam.mx [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apdo. Postal 20-364, Mexico D.F. 01000 (Mexico)

2011-08-15

390

Development of a Cl-impregnated activated carbon for entrained-flow capture of elemental mercury.  

PubMed

Efforts to discern the role of an activated carbon's surface functional groups on the adsorption of elemental mercury (Hg0) and mercuric chloride demonstrated that chlorine (Cl) impregnation of a virgin activated carbon using dilute solutions of hydrogen chloride leads to increases (by a factor of 2-3) in fixed-bed capture of these mercury species. A commercially available activated carbon (DARCO FGD, NORITAmericas Inc. [FGD])was Cl-impregnated (Cl-FGD) [5 lb (2.3 kg) per batch] and tested for entrained-flow, short-time-scale capture of Hg0. In an entrained flow reactor, the Cl-FGD was introduced in Hg0-laden flue gases (86 ppb of Hg0) of varied compositions with gas/solid contact times of about 3-4 s, resulting in significant Hg0 removal (80-90%), compared to virgin FGD (10-15%). These levels of Hg0 removal were observed across a wide range of very low carbon-to-mercury weight ratios (1000-5000). Variation of the natural gas combustion flue gas composition, by doping with nitrogen oxides and sulfur dioxide, and the flow reactor temperature (100-200 degrees C) had minimal effects on Hg0 removal bythe Cl-FGD in these carbon-to-mercury weight ratios. These results demonstrate significant enhancement of activated carbon reactivity with minimal treatment and are applicable to combustion facilities equipped with downstream particulate matter removal such as an electrostatic precipitator. PMID:12387423

Ghorishi, S Behrooz; Keeney, Robert M; Serre, Shannon D; Gullett, Brian K; Jozewicz, Wojciech S

2002-10-15

391

An Experimental Comparison of Min-Cut\\/Max-Flow Algorithms for Energy Minimization in Vision  

Microsoft Academic Search

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

Yuri Boykov; Vladimir Kolmogorov

2004-01-01

392

An Experimental Comparison of Min-cut\\/Max-flow Algorithms for Energy Minimization in Vision  

Microsoft Academic Search

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

Yuri Boykov; Vladimir Kolmogorov

2001-01-01

393

MAGNETIC ENERGY AND HELICITY IN TWO EMERGING ACTIVE REGIONS IN THE SUN  

SciTech Connect

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.

Liu, Y. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States); Schuck, P. W. [Space Weather Laboratory, Code 674, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2012-12-20

394

Residual-Energy-Activated Cooperative Transmission (REACT) to Avoid the Energy Hole  

E-print Network

Residual-Energy-Activated Cooperative Transmission (REACT) to Avoid the Energy Hole Jin Woo Jung. We develop this idea into a distributed pro- tocol which we call "Residual-Energy-Activated, the nodes that are one hop away from the Sink die first and cause an "energy hole," because they must

Ingram, Mary Ann

395

Energy Conservation Activities for Elementary Grades (Or: How To Help Slim Down the Energy Monster). Iowa Developed Energy Activities Sampler, Primary K-2. Revised.  

ERIC Educational Resources Information Center

The revised Iowa Developed Energy Activity Sampler (IDEAS) was compiled using the original IDEAS program and the Energy Conservation Activity Packets (ECAPS). This booklet provides activities for teachers to use in the primary elementary grades (K-2). The activities are organized into nine units, with units 1 through 8 containing three activities

Iowa State Dept. of Education, Des Moines.

396

System size, energy and pseudorapidity dependence of directed and elliptic flow at RHIC  

E-print Network

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.

S. Manly

2005-10-10

397

Redox ion flow cell for solar energy storage  

Microsoft Academic Search

Redox cells which can be used as a storage system with solar cell or wind powered electrical generating plants are explored. Fluid reaction partners are a means to provide reversible processes that can withstand long-term cycling and still be economical. A redox cell stores energy in the form of solutions of metal ion pairs at different oxidation states, such as

H. Cnobloch; W. Kellermann; H. Nischik; K. Pantel; G. Siemsen

1983-01-01

398

Experimental Studies of Active and Passive Flow Control Techniques Applied in a Twin Air-Intake  

PubMed Central

The flow control in twin air-intakes is necessary to improve the performance characteristics, since the flow traveling through curved and diffused paths becomes complex, especially after merging. The paper presents a comparison between two well-known techniques of flow control: active and passive. It presents an effective design of a vortex generator jet (VGJ) and a vane-type passive vortex generator (VG) and uses them in twin air-intake duct in different combinations to establish their effectiveness in improving the performance characteristics. The VGJ is designed to insert flow from side wall at pitch angle of 90 degrees and 45 degrees. Corotating (parallel) and counterrotating (V-shape) are the configuration of vane type VG. It is observed that VGJ has the potential to change the flow pattern drastically as compared to vane-type VG. While the VGJ is directed perpendicular to the side walls of the air-intake at a pitch angle of 90 degree, static pressure recovery is increased by 7.8% and total pressure loss is reduced by 40.7%, which is the best among all other cases tested for VGJ. For bigger-sized VG attached to the side walls of the air-intake, static pressure recovery is increased by 5.3%, but total pressure loss is reduced by only 4.5% as compared to all other cases of VG. PMID:23935422

Joshi, Shrey; Jindal, Aman; Maurya, Shivam P.; Jain, Anuj

2013-01-01

399

Experimental studies of active and passive flow control techniques applied in a twin air-intake.  

PubMed

The flow control in twin air-intakes is necessary to improve the performance characteristics, since the flow traveling through curved and diffused paths becomes complex, especially after merging. The paper presents a comparison between two well-known techniques of flow control: active and passive. It presents an effective design of a vortex generator jet (VGJ) and a vane-type passive vortex generator (VG) and uses them in twin air-intake duct in different combinations to establish their effectiveness in improving the performance characteristics. The VGJ is designed to insert flow from side wall at pitch angle of 90 degrees and 45 degrees. Corotating (parallel) and counterrotating (V-shape) are the configuration of vane type VG. It is observed that VGJ has the potential to change the flow pattern drastically as compared to vane-type VG. While the VGJ is directed perpendicular to the side walls of the air-intake at a pitch angle of 90 degree, static pressure recovery is increased by 7.8% and total pressure loss is reduced by 40.7%, which is the best among all other cases tested for VGJ. For bigger-sized VG attached to the side walls of the air-intake, static pressure recovery is increased by 5.3%, but total pressure loss is reduced by only 4.5% as compared to all other cases of VG. PMID:23935422

Paul, Akshoy Ranjan; Joshi, Shrey; Jindal, Aman; Maurya, Shivam P; Jain, Anuj

2013-01-01

400

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

SciTech Connect

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.

Kehler, P.

1982-03-01

401

Salivary Alpha-Amylase Activity and Salivary Flow Rate in Young Adults  

PubMed Central

The secretion of salivary alpha-amylase (sAA) is more associated with psychoneuroendocrinological response to stress than with the flow rate and age. The aim of this cross sectional study is to build an explanatory model based on patterns of relationship between age 20-39 in resting and stimulated saliva under no stressful condition in healthy volunteers. Both resting and stimulated saliva were collected from 40 subjects. The sAA values were log-transformed, the normality assumption was verified with the Shapiro-Wilk test and the reliability of the measurements was estimated by the Pearsons r correlation coefficient. The estimated model was based on the theory of the Linear Mixed Models. Significant mean changes were observed in flow rate and sAA activity between resting and stimulated saliva. The final model consists of two components, the first revealed a positive correlation between age and sAA while the second one revealed a negative correlation between the interaction of age flow rate in its condition (resting or stimulated saliva), with sAA. Both flow rate and age influence sAA activity. PMID:23524385

Arhakis, Aristidis; Karagiannis, Vasilis; Kalfas, Sotirios

2013-01-01

402

Numerical simulation of material and energy flow in an e-beam melt furnace  

SciTech Connect

A numerical analysis is made of the material and energy flow in an electron-beam furnace. Energy from an electron beam vaporizes metal confined in a water-cooled crucible. At the beam impact site a. recirculating liquid metal pool is surrounded by a shell of its own solid. A Galerkin finite element method is modified to solve for the flow and temperature fields along with interface locations. The deforming mesh is parameterized using spines that pivot and stretch as the interfaces move. Results are given for an aluminum vaporizer in which parametric variations are made in the e-beam power and liquid viscosity. The calculations reveal the importance of the coupling between the free boundaries and the flow and energy fields.

Westerberg, K.W.; McClelland, M.A. [Lawrence Livermore National Lab., CA (United States); Finlayson, B.A. [Washington Univ., Seattle, WA (United States). Dept. of Chemical Engineering

1993-12-01

403

Reduced order modeling and active flow control of an inlet duct  

NASA Astrophysics Data System (ADS)

Many aerodynamic applications require the modeling of compressible flows in or around a body, e.g., the design of aircraft, inlet or exhaust duct, wind turbines, or tall buildings. Traditional methods use wind tunnel experiments and computational fluid dynamics (CFD) to investigate the spatial and temporal distribution of the flows. Although they provide a great deal of insight into the essential characteristics of the flow field, they are not suitable for control analysis and design due to the high physical/computational cost. Many model reduction methods have been studied to reduce the complexity of the flow model. There are two main approaches: linearization based input/output modeling and proper orthogonal decomposition (POD) based model reduction. The former captures mostly the local behavior near a steady state, which is suitable to model laminar flow dynamics. The latter obtains a reduced order model by projecting the governing equation onto an "optimal" subspace and is able to model complex nonlinear flow phenomena. In this research we investigate various model reduction approaches and compare them in flow modeling and control design. We propose an integrated model-based control methodology and apply it to the reduced order modeling and active flow control of compressible flows within a very aggressive (length to exit diameter ratio, L/D, of 1.5) inlet duct and its upstream contraction section. The approach systematically applies reduced order modeling, estimator design, sensor placement and control design to improve the aerodynamic performance. The main contribution of this work is the development of a hybrid model reduction approach that attempts to combine the best features of input/output model identification and POD method. We first identify a linear input/output model by using a subspace algorithm. We next project the difference between CFD response and the identified model response onto a set of POD basis. This trajectory is fit to a nonlinear dynamical model to augment the linear input/output model. Thus, the full system is decomposed into a dominant linear subsystem and a low order nonlinear subsystem. The hybrid model is then used for control design and compared with other modeling methods in CFD simulations. Numerical results indicate that the hybrid model accurately predicts the nonlinear behavior of the flow for a 2D diffuser contraction section model. It also performs best in terms of feedback control design and learning control. Since some outputs of interest (e.g., the AIP pressure recovery) are not observable during normal operations, static and dynamic estimators are designed to recreate the information from available sensor measurements. The latter also provides a state estimation for feedback controller. Based on the reduced order models and estimators, different controllers are designed to improve the aerodynamic performance of the contraction section and inlet duct. The integrated control methodology is evaluated with CFD simulations. Numerical results demonstrate the feasibility and efficacy of the active flow control based on reduced order models. Our reduced order models not only generate a good approximation of the nonlinear flow dynamics over a wide input range, but also help to design controllers that significantly improve the flow response. The tools developed for model reduction, estimator and control design can also be applied to wind tunnel experiment.

Ge, Xiaoqing

404

Catalytic electrodes for the Redox Flow Cell energy storage device  

Microsoft Academic Search

Several porous electrode materials have been studied for the redox couple Cr3+\\/Cr2+. The electrochemically active surface area, the hydrogen evolution overpotential and the limiting current of the chromium redox reactions were measured. Useful kinetic parameters can be deduced although their accuracies are limited due to the porous nature of the materials studied. The results presented will primarily be for one

C. Y. Yang

1982-01-01

405

Analysis of transient sound energy flow in impact noise  

NASA Astrophysics Data System (ADS)

The formative mechanism and characteristics of the initial transient sound field caused by the transient vibration response of a clamped circular plate are analyzed using an external point force with a squared half-period sine-wave time history. The dynamic and acoustic responses of a circular plate are expressed by using both the dimensionless parameter beta introduced by the group velocity of the dominant frequency component and the dimensionless parameter gamma introduced by the sound speed in the acoustic medium. From the analysis the following results were obtained. First, the propagation of kinetic energy can be seen by observing the period from about 0 to 2/beta. Second, dimensionless sound energy radiation patterns from the plate rely on beta. Third, the maximum instantaneous sound intensity on the axis of symmetry is formed by sound radiated from principal modal bending waves which are reflected at the edge of the circular plate.

Nakagawa, Noritoshi; Iwatsubo, Takuzo; Sahara, Shinsuke

1988-09-01

406

Chemical energy release and dynamics of transitional, reactive shear flows  

Microsoft Academic Search

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

F. F. Grinstein; K. Kailasanath

1992-01-01

407

The signature of dark energy on the local Hubble flow  

Microsoft Academic Search

Using N-body simulations of flat, dark energy-dominated cosmologies, we show that galaxies around simulated binary systems resembling the Local Group (LG) have low peculiar velocities, in good agreement with observational data. We have compared results for LG-like systems selected from large, high-resolution simulations of three cosmologies: a LambdaCDM model, a LambdaWDM model with a 2-keV warm dark matter candidate, and

Andrea V. Macci; Fabio Governato; Cathy Horellou

2005-01-01

408

Maneuvering Aspects and 3D Effects of Active Airfoil Flow Control  

Microsoft Academic Search

An active flow control experiment was conducted on a cropped NACA 0018 airfoil to study 3D effects and maneuverability aspects\\u000a made possible by a segmented actuation system installed in the airfoil. The 14 piezo-fluidic actuators were installed at the\\u000a corner of the cropped region, inclined at 30 to the local surface, facing downstream. Operating all actuators at unison significantly\\u000a increased

Itay Timor; Eli Ben-Hamou; Yair Guy; Avi Seifert

2007-01-01

409

Analysis of active lava flows on Kilauea volcano, Hawaii, using SIR-C radar correlation measurements  

Microsoft Academic Search

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). A coastal site downslope from the Pu'u O'o vent was imaged once per day, on each of the four days of October 7 10, 1994. Day-to-day decorrelation due to resurfacing was determined by

Howard A. Zebker; Paul Rosen; Scott Hensley; Peter J. Mouginis-Mark

1996-01-01

410

Cooling rate of an active Hawaiian lava flow from nighttime spectroradiometer measurements  

Microsoft Academic Search

A narrow-band spectroradiometer has been used to make nighttime measurements of the Phase 50 eruption of Pu'u O'o, on the East Rift Zone of Kilauea Volcano, Hawaii. On February 19, 1992, a GER spectroradiometer was used to determine the cooling rate of an active lava flow. This instrument collects 12-bit data between 0.35 to 3.0 microns at a spectral resolution

Luke P. Flynn; Peter J. Mouginis-Mark

1992-01-01

411

Cooling rate of an active Hawaiian lava flow from nighttime spectroradiometer measurements  

Microsoft Academic Search

A narrow-band spectroradiometer has been used to make nighttime measurements of the Phase 50 eruption of Pu'u O'o, on the East Rift Zone of Kilauea Volcano, Hawaii. On February 19, 1992, a GER spectroradiometer was used to determine the cooling rate of an active lava flow. This instrument collects 12-bit data between 0.35 to 3.0 ?m at a spectral resolution

Luke P. Flynn; Peter J. Mouginis-Mark

1992-01-01

412

Exhausting handgrip exercise reduces the blood flow in the active calf muscle exercising at low intensity  

Microsoft Academic Search

The calf and forearm blood flows (Q\\u000acalf and Q\\u000aforearm respectively), blood pressure, heart rate and oxygen uptake of six men and women were studied during combined leg and handgrip exercise to determine whether a reduction of exercise-induced hyperaemia would occur in the active leg when exhausting rhythmic handgrip exercise at 50% maximal voluntary contraction (MVC) was superimposed upon

Atsuko Kagaya; Mitsuru Saito; Futoshi Ogita; Minoru Shinohara

1994-01-01

413

Valuing uncertain cash flows from investments that enhance energy efficiency.  

PubMed

There is a broad consensus that investments to enhance energy efficiency quickly pay for themselves in lower energy bills and spared emission allowances. However, investments that at first glance seem worthwhile usually are not undertaken. One of the plausible, non-excluding explanations is the numerous uncertainties that these investments face. This paper deals with the optimal time to invest in an energy efficiency enhancement at a facility already in place that consumes huge amounts of a fossil fuel (coal) and operates under carbon constraints. We follow the Real Options approach. Our model comprises three sources of uncertainty following different stochastic processes which allows for application in a broad range of settings. We assess the investment option by means of a three-dimensional binomial lattice. We compute the trigger investment cost, i.e., the threshold level below which immediate investment would be optimal. We analyze the major drivers of this decision thus aiming at the most promising policies in this regard. PMID:23295678

Abadie, Luis M; Chamorro, Jos M; Gonzlez-Eguino, Mikel

2013-02-15

414

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

This document contains material and energy flows for lithium-ion batteries with an active cathode material of lithium manganese oxide (LiMnO). 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

J. B. Dunn; L. Gaines; M. Barnes; M. Wang; J. Sullivan

2012-01-01

415

Pressure distribution and energy flow in the focal region of two different electromagnetic shock wave sources.  

PubMed

In extracorporeal shock wave lithotripsy there is still a lack of knowledge about the basic physical terms that are essential for a scientific comparison of lithotripters with different technologies. The main goal of this article is to introduce the relation between pressure distribution, acoustic energy flow and intensity. The procedure of how these data can be achieved quantitatively is described. Technical data of two different commercially available electromagnetic shock wave sources are presented. The results show that acoustic energy flow and intensity depend on the variation of the shock wave parameters and the focal area. PMID:10149172

Folberth, W; Khler, G; Rohwedder, A; Matura, E

1992-01-01

416

Estimation of activity energy expenditure: accelerometer approach.  

PubMed

A novel algorithm estimating the calorie expenditure during physical activities is introduced. The physical activity is quantified by the integration of the accelerometer signals obtained from the 3D accelerometer fixed at the waist level of the human body. Simultaneous measurements of activity and calorie expenditure using 3D accelerometer and gas analyzer show the activity calorie expenditure increases as the activity increases with different rates depending on the type of activities (e.g., walking, running) as well as the physical characteristics of the subjects (e.g., gender, age, mass, and height). Based on the experimental data gathered from 94 subjects, we suggest a new algorithm estimating the activity calorie expenditure dependent on the demographic data of the subjects and the types of the activity. PMID:17281065

Hyun Choi, Jee; Lee, Jeongwhan; Tai Hwang, Hyun; Pal Kim, Jong; Chan Park, Jae; Shin, Kunsoo

2005-01-01

417

Serum metabolites related to cardiorespiratory fitness, physical activity energy expenditure, sedentary time and vigorous activity.  

PubMed

The aim of our study was to investigate the relationship between objectively measured physical activity (PA) and cardiorespiratory fitness (CRF) and serum metabolites measured by targeted metabolomics in a population- based study. A total of 100 subjects provided 2 fasting blood samples and engaged in a CRF and PA measurement at 2 visits 4 months apart. CRF was estimated from a step test, whereas physical activity energy expenditure (PAEE), time spent sedentary and time spend in vigorous activity were measured by a combined heart rate and movement sensor for a total of 8 days. Serum metabolite concentrations were determined by flow injection analysis tandem mass spectrometry (FIA-MS/MS). Linear mixed models were applied with multivariable adjustment and p-values were corrected for multiple testing. Furthermore, we explored the associations between CRF, PA and two metabolite factors that have previously been linked to risk of Type 2 diabetes. CRF was associated with two phosphatidylcholine clusters independently of all other exposures. Lysophosphatidylcholine C14:0 and methionine were significantly negatively associated with PAEE and sedentary time. CRF was positively associated with the Type 2 diabetes protective factor. Vigorous activity was positively associated with the Type 2 diabetes risk factor in the mutually adjusted model. Our results suggest that CRF and PA are associated with serum metabolites, especially CRF with phosphatidylcholines and with the Type 2 diabetes protective factor. PAEE and sedentary time were associated with methionine. The identified metabolites could be potential mediators of the protective effects of CRF and PA on chronic disease risk. PMID:24226038

Wientzek, Angelika; Floegel, Anna; Knppel, Sven; Vigl, Matthaeus; Drogan, Dagmar; Adamski, Jerzy; Pischon, Tobias; Boeing, Heiner

2014-04-01

418

Solar Energy Education. Renewable energy activities for chemistry and physics  

SciTech Connect

Information on renewable energy sources is provided for students in this teachers' guide. With the chemistry and physics student in mind, solar energy topics such as absorber plate coatings for solar collectors and energy collection and storage methods are studied. (BCS)

Not Available

1985-01-01

419

Lightstick Magic: Determination of the Activation Energy with PSL.  

ERIC Educational Resources Information Center

Presents experiments with lightsticks in which the activation energy for the light-producing reaction is determined. Involves monitoring the light intensity of the lightstick as a function of temperature. Gives students the opportunity to explore the concepts of kinetics and activation energies and the world of computer-interfaced experimentation

Bindel, Thomas H.

1996-01-01

420

Biomass I. Science Activities in Energy [and] Teacher's Guide.  

ERIC Educational Resources Information Center

Designed for science students in fourth, fifth, and sixth grades, the activities in this unit illustrate principles and problems related to biomass as a form of energy. (The word biomass is used to describe all solid material of animal or vegetable origin from which energy may be extracted.) Twelve student activities using art, economics,

Oak Ridge Associated Universities, TN.

421

Energy Conservation Activity Packet, Grade 3. Revised Edition.  

ERIC Educational Resources Information Center

This notebook for grade 3 is one of a series 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 grade three. The packet is divided into two parts and provides the teacher with background information, concepts and

Pohlman, Betty; And Others

422

Energy Conservation Activities for Elementary Grades (Or: How to Help Slim Down the Energy Monster). Iowa Developed Energy Activities Sampler, Intermediate 3-5.  

ERIC Educational Resources Information Center

The revised Iowa Developed Energy Activity Sampler (IDEAS) was compiled using the original IDEAS program and the Energy Conservation Activity Packets (ECAPS). This booklet provides activities for teachers in the intermediate elementary grades (3-5) and is designed to enable students to develop a comprehensive understanding of energy concepts. Each

Iowa State Dept. of Education, Des Moines. Div. of Instructional Services.

423

Energy Conservation Activities for Elementary Grades (Or: How To Help Slim Down the Energy Monster). Iowa Developed Energy Activities Sampler, Intermediate 3-5. Revised.  

ERIC Educational Resources Information Center

The revised Iowa Developed Energy Activity Sampler (IDEAS) was compiled using the original IDEAS program and the Energy Conservation Activity Packets (ECAPS). This booklet provides activities for teachers in the intermediate elementary grades (3-5) and is designed to enable students to develop a comprehensive understanding of energy concepts. Each

Iowa State Dept. of Education, Des Moines.

424

Energy flux fluctuations in a finite volume of turbulent flow  

E-print Network

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.

Mahesh Bandi; Walter Goldburg; John Cressman Jr.; Alain Pumir

2006-07-19

425

Boltzmann rovibrational collisional coarse-grained model for internal energy excitation and dissociation in hypersonic flows  

NASA Astrophysics Data System (ADS)

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 N2-N interactions. The coarse-grained model is constructed by lumping the rovibrational energy levels of the N2 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.

Munaf, A.; Panesi, M.; Magin, T. E.

2014-02-01

426

Progress Towards Fuselage Drag Reduction via Active Flow Control: A Combined CFD and Experimental Effort  

NASA Technical Reports Server (NTRS)

A combined computational and experimental effort has been undertaken to study fuselage drag reduction on a generic, non-proprietary rotorcraft fuselage by the application of active ow control. Fuselage drag reduction is an area of research interest to both the United States and France and this area is being worked collaboratively as a task under the United States/France Memorandum of Agreement on Helicopter Aeromechanics. In the first half of this task, emphasis is placed on the US generic fuselage, the ROBIN-mod7, with the experimental work being conducted on the US side and complementary US and French CFD analysis of the baseline and controlled cases. Fuselage simulations were made using Reynolds-averaged Navier-Stokes ow solvers and with multiple turbulence models. Comparisons were made to experimental data for numerical simulations of the isolated fuselage and for the fuselage as installed in the tunnel, which includes modeling of the tunnel contraction, walls, and support fairing. The numerical simulations show that comparisons to the experimental data are in good agreement when the tunnel and model support are included. The isolated fuselage simulations compare well to each other, however, there is a positive shift in the centerline pressure when compared to the experiment. The computed flow separation locations on the rear ramp region had only slight differences with and without the tunnel walls and model support. For the simulations, the flow control slots were placed at several locations around the flow separation lines as a series of eight slots that formed a nearly continuous U-shape. Results from the numerical simulations resulted in an estimated 35% fuselage drag reduction from a steady blowing flow control configuration and a 26% drag reduction for unsteady zero-net-mass flow control configuration. Simulations with steady blowing show a delayed flow separation at the rear ramp of the fuselage that increases the surface pressure acting on the ramp, thus decreasing the overall fuselage pressure drag.

Schaefler, Norman W.; Allan, Brian G.; Lienard, Caroline; LePape, Arnaud

2010-01-01

427

Transferring the concept of minimum energy dissipation from river networks to subsurface flow patterns  

NASA Astrophysics Data System (ADS)

Principles of optimality provide an interesting alternative to modeling hydrological processes in detail on small scales and have received growing interest in the last years. Inspired by the more than 20 years old concept of minimum energy dissipation in river networks, we present a corresponding theory for subsurface flow in order to obtain a better understanding of preferential flow patterns in the subsurface. The concept describes flow patterns which are optimal in the sense of minimizing the total energy dissipation at a given recharge under the constraint of a given total porosity. Results are illustrated using two examples: two-dimensional flow towards a spring with a radial symmetric distribution of the porosity and dendritic flow patterns. The latter are found to be similar to river networks in their structure and, as a main result, the model predicts a power-law distribution of the spring discharges. In combination with two data sets from the Austrian Alps, this result is used for validating the model. Both data sets reveal power-law-distributed spring discharges with similar scaling exponents. These are, however, slightly larger than the exponent predicted by the model. As a further result, the distributions of the residence times strongly differ between homogeneous porous media and optimized flow patterns, while the mean residence times are similar in both cases.

Hergarten, S.; Winkler, G.; Birk, S.

2014-10-01

428

Active energy harvesting from microbial fuel cells at the maximum power point without using resistors.  

PubMed

Microbial fuel cell (MFC) technology offers a sustainable approach to harvest electricity from biodegradable materials. Energy production from MFCs has been demonstrated using external resistors or charge pumps, but such methods can only dissipate energy through heat or receive electrons passively from the MFC without any controllability. This study developed a new approach and system that can actively extract energy from MFC reactors at any operating point without using any resistors, especially at the peak power point to maximize energy production. Results show that power harvesting from a recirculating-flow MFC can be well maintained by the maximum power point circuit (MPPC) at its peak power point, while a charge pump was not able to change operating point due to current limitation. Within 18-h test, the energy gained from the MPPC was 76.8 J, 76 times higher than the charge pump (1.0 J) that was commonly used in MFC studies. Both conditions resulted in similar organic removal, but the Coulombic efficiency obtained from the MPPC was 21 times higher than that of the charge pump. Different numbers of capacitors could be used in the MPPC for various energy storage requirements and power supply, and the energy conversion efficiency of the MPPC was further characterized to identify key factors for system improvement. This active energy harvesting approach provides a new perspective for energy harvesting that can maximize MFC energy generation and system controllability. PMID:22486712

Wang, Heming; Park, Jae-Do; Ren, Zhiyong

2012-05-01

429

Energy Prediction Based on Resident's Activity Washington State University  

E-print Network

Energy Prediction Based on Resident's Activity Chao Chen Washington State University Pullman, WA environment research, little attention has been given to monitoring, analyzing, and predicting energy usage envision that a potential application of this smart environment technology is predicting the energy would

Cook, Diane J.

430

Highlands County Energy Education Activities--High School Level.  

ERIC Educational Resources Information Center

Presented are five instructional units, developed by the Tri-County Teacher Education Center, for the purpose of educating secondary school students on Florida's unique energy problems. Unit one provides a series of value clarification and awareness activities as an introduction to energy. Unit two uses mathematics exercises to examine energy

Allen, Rodney F., Ed.

431

The Horizontal Component of Photospheric Plasma Flows During the Emergence of Active Regions on the Sun  

NASA Astrophysics Data System (ADS)

The dynamics of horizontal plasma flows during the first hours of the emergence of active region magnetic flux in the solar photosphere have been analyzed using SOHO/MDI data. Four active regions emerging near the solar limb have been considered. It has been found that extended regions of Doppler velocities with different signs are formed in the first hours of the magnetic flux emergence in the horizontal velocity field. The flows observed are directly connected with the emerging magnetic flux; they form at the beginning of the emergence of active regions and are present for a few hours. The Doppler velocities of flows observed increase gradually and reach their peak values 4 - 12 hours after the start of the magnetic flux emergence. The peak values of the mean (inside the 500 m s-1 isolines) and maximum Doppler velocities are 800 - 970 m s-1 and 1410 - 1700 m s-1, respectively. The Doppler velocities observed substantially exceed the separation velocities of the photospheric magnetic flux outer boundaries. The asymmetry was detected between velocity structures of leading and following polarities. Doppler velocity structures located in a region of leading magnetic polarity are more powerful and exist longer than those in regions of following polarity. The Doppler velocity asymmetry between the velocity structures of opposite sign reaches its peak values soon after the emergence begins and then gradually drops within 7 - 12 hours. The peak values of asymmetry for the mean and maximal Doppler velocities reach 240 - 460 m s-1 and 710 - 940 m s-1, respectively. An interpretation of the observable flow of photospheric plasma is given.

Khlystova, A.

2013-06-01

432

Energy consumption and economic activities in Iran  

Microsoft Academic Search

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 19672003. 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

Mehrzad Zamani

2007-01-01

433

Conical Euler analysis and active roll suppression for unsteady vortical flows about rolling delta wings  

NASA Technical Reports Server (NTRS)

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.

Lee-Rausch, Elizabeth M.; Batina, John T.

1993-01-01

434

Investigation of Active Flow Control to Improve Aerodynamic Performance of Oscillating Wings  

NASA Technical Reports Server (NTRS)

The objective of this effort is to design a promising active flow control concept on an oscillating airfoil for on-blade alleviation of dynamic stall. The concept must be designed for a range of representative Mach numbers (0.2 to 0.5) and representative reduced frequency characteristics of a full-scale rotorcraft. Specifications for a sweeping-jet actuator to mitigate the detrimental effects of retreating blade stall experienced by edgewise rotors in forward flight has been performed. Wind tunnel modifications have been designed to accommodate a 5x6 test section in the Oran W. Nicks Low Speed Wind Tunnel at Texas A&M University that will allow the tunnel to achieve Mach 0.5. The flow control design is for a two-dimensional oscillating VR-7 blade section with a 15- inch chord at rotor-relevant flow conditions covering the range of reduced frequencies from 0.0 to 0.15 and Mach numbers from 0.2 to 0.5. A Computational Fluid Dynamics (CFD) analysis has been performed to influence the placement of the flow control devices for optimal effectiveness.

Narducci, Robert P.; Bowersox, Rodney; Bussom, Richard; McVeigh, Michael; Raghu, Surya; White, Edward

2014-01-01

435

Active Flow Separation Control of a Stator Vane Using Surface Injection in a Multistage Compressor Experiment  

NASA Technical Reports Server (NTRS)

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.

Culley, Dennis E.; Bright, Michelle M.; Prahst, Patricia S.; Strazisar, Anthony J.

2003-01-01

436

Design of a high-lift experiment in water including active flow control  

NASA Astrophysics Data System (ADS)

This paper describes the structural design of an active flow-control experiment. The aim of the experiment is to investigate the increase in efficiency of an internally blown Coanda flap using unsteady blowing. The system uses tailor-made microelectromechanical (MEMS) pressure sensors to determine the state of the oncoming flow and an actuated lip to regulate the mass flow and velocity of a stream near a wall over the internally blown flap. Sensors and actuators are integrated into a highly loaded system that is extremely compact. The sensors are connected to a bus system that feeds the data into a real-time control system. The piezoelectric actuators using the d 33 effect at a comparable low voltage of 120 V are integrated into a lip that controls the blowout slot height. The system is designed for closed-loop control that efficiently avoids flow separation on the Coanda flap. The setup is designed for water-tunnel experiments in order to reduce the free-stream velocity and the systems control frequency by a factor of 10 compared with that in air. This paper outlines the function and verification of the systems main components and their development.

Beutel, T.; Sattler, S.; El Sayed, Y.; Schwerter, M.; Zander, M.; Bttgenbach, S.; Leester-Schdel, M.; Radespiel, R.; Sinapius, M.; Wierach, P.

2014-07-01

437

Energy Conservation Activities for Elementary Grades (Or: How to Help Slim Down the Energy Monster). Iowa Developed Energy Activities Sampler, Primary K-2.  

ERIC Educational Resources Information Center

The revised Iowa Developed Energy Activity Sampler (IDEAS) was compiled using the original IDEAS program and the Energy Conservation Activity Packets (ECAPS). This booklet provides activities for teachers to use in the primary elementary grades (K-2). The activities are organized into nine units, with units I through VIII containing three

Iowa State Dept. of Education, Des Moines. Div. of Instructional Services.

438

Airfoil leading-edge suction and energy conservation for compressible flow  

SciTech Connect

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.

Amiet, R.K.

1995-04-01

439

Energy elastic effects and the concept of temperature in flowing polymeric liquids  

Microsoft Academic Search

The incorporation of energy elastic effects in the modeling of flowing polymeric liquids is discussed. Since conformational\\u000a energetic effects are determined by structural features much smaller than the end-to-end vector of the polymer chains, commonly\\u000a employed single conformation tensor models are insufficient to describe energy elastic effects. The need for a local structural\\u000a variable is substantiated by studying a microscopic

Markus Htter; Clarisse Luap; Hans Christian ttinger

2009-01-01

440

Measurement of anisotropic energy transport in flowing polymers by using a holographic technique  

PubMed Central

Almost no experimental data exist to test theories for the nonisothermal flow of complex fluids. To provide quantitative tests for newly proposed theories, we have developed a holographic grating technique to study energy transport in an amorphous polymer melt subject to flow. Polyisobutylene with weight-averaged molecular mass of 85 kDa is sheared at a rate of 10 s1, and all nonzero components of the thermal conductivity tensor are measured as a function of time, after cessation. Our results are consistent with proposed generalizations to the energy balance for microstructural fluids, including a generalized Fourier's law for anisotropic media. The data are also consistent with a proposed stress-thermal rule for amorphous polymer melts. Confirmation of the universality of these results would allow numerical modelers to make quantitative predictions for the nonisothermal flow of polymer melts. PMID:15340152

Schieber, Jay D.; Venerus, David C.; Bush, Kendall; Balasubramanian, Venkat; Smoukov, Stoyan

2004-01-01

441

Measurement of anisotropic energy transport in flowing polymers by using a holographic technique.  

PubMed

Almost no experimental data exist to test theories for the nonisothermal flow of complex fluids. To provide quantitative tests for newly proposed theories, we have developed a holographic grating technique to study energy transport in an amorphous polymer melt subject to flow. Polyisobutylene with weight-averaged molecular mass of 85 kDa is sheared at a rate of 10 s(-1), and all nonzero components of the thermal conductivity tensor are measured as a function of time, after cessation. Our results are consistent with proposed generalizations to the energy balance for microstructural fluids, including a generalized Fourier's law for anisotropic media. The data are also consistent with a proposed stress-thermal rule for amorphous polymer melts. Confirmation of the universality of these results would allow numerical modelers to make quantitative predictions for the nonisothermal flow of polymer melts. PMID:15340152

Schieber, Jay D; Venerus, David C; Bush, Kendall; Balasubramanian, Venkat; Smoukov, Stoyan

2004-09-01

442

Numerical Simulation on the Continuous Operation of an Aquifer Thermal Energy Storage System Under Regional Groundwater Flow  

Microsoft Academic Search

A three-dimensional numerical model for groundwater flow and heat transport is used to analyze an aquifer thermal energy storage system operating under a continuous flow regime. This study emphasizes the influence of regional groundwater flow on the performance of the system under various operation scenarios. The pressure gradient across the system, which determines the direction and velocity of regional groundwater

K. S. Lee

2011-01-01

443

A two-phase shallow debris flow model with energy F. Bouchut  

E-print Network

. This model is derived from a 3D two-phase model based on the equations proposed by Jackson [R. Jackson within the two phases, i.e. two vector and two scalar equations. This system has five unknowns: the solidA two-phase shallow debris flow model with energy balance F. Bouchut , E.D. Fern´andez-Nieto , A

Recanati, Catherine