WorldWideScience

Sample records for deliver mechanical energy

  1. Energy Provider: Delivered Energy Efficiency: A global stock-taking based on case studies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-06-01

    In 2011 the IEA and the Regulatory Assistance Project (RAP) took on a work programme focused on the role of energy providers in delivering energy efficiency to end-users. This work was part of the IEA’s contribution to the PEPDEE Task Group, which falls under the umbrella of the International Partnership on Energy Efficiency Cooperation (IPEEC). In addition to organizing regional dialogues between governments, regulators, and energy providers, the PEPDEE work stream conducted global stock-takings of regulatory mechanisms adopted by governments to obligate or encourage energy providers to delivery energy savings and the energy savings activities of energy providers. For its part the IEA conducted a global review of energy provider-delivered energy savings programmes. The IEA reached out to energy providers to identify the energy savings activities they engaged in. Some 250 energy saving activities were considered, and 41 detailed case studies spanning 18 countries were developed. Geographic balance was a major consideration, and much effort was expended identifying energy provider-delivered energy savings case studies from around the world. Taken together these case studies represent over USD 1 billion in annual spending, or about 8% of estimated energy provider spending on energy efficiency.

  2. Energy Servers Deliver Clean, Affordable Power

    Science.gov (United States)

    2010-01-01

    K.R. Sridhar developed a fuel cell device for Ames Research Center, that could use solar power to split water into oxygen for breathing and hydrogen for fuel on Mars. Sridhar saw the potential of the technology, when reversed, to create clean energy on Earth. He founded Bloom Energy, of Sunnyvale, California, to advance the technology. Today, the Bloom Energy Server is providing cost-effective, environmentally friendly energy to a host of companies such as eBay, Google, and The Coca-Cola Company. Bloom's NASA-derived Energy Servers generate energy that is about 67-percent cleaner than a typical coal-fired power plant when using fossil fuels and 100-percent cleaner with renewable fuels.

  3. Geothermal Energy: Delivering on the Global Potential

    Directory of Open Access Journals (Sweden)

    Paul L. Younger

    2015-10-01

    Full Text Available Geothermal energy has been harnessed for recreational uses for millennia, but only for electricity generation for a little over a century. Although geothermal is unique amongst renewables for its baseload and renewable heat provision capabilities, uptake continues to lag far behind that of solar and wind. This is mainly attributable to (i uncertainties over resource availability in poorly-explored reservoirs and (ii the concentration of full-lifetime costs into early-stage capital expenditure (capex. Recent advances in reservoir characterization techniques are beginning to narrow the bounds of exploration uncertainty, both by improving estimates of reservoir geometry and properties, and by providing pre-drilling estimates of temperature at depth. Advances in drilling technologies and management have potential to significantly lower initial capex, while operating expenditure is being further reduced by more effective reservoir management—supported by robust models—and increasingly efficient energy conversion systems (flash, binary and combined-heat-and-power. Advances in characterization and modelling are also improving management of shallow low-enthalpy resources that can only be exploited using heat-pump technology. Taken together with increased public appreciation of the benefits of geothermal, the technology is finally ready to take its place as a mainstream renewable technology, exploited far beyond its traditional confines in the world’s volcanic regions.

  4. Delivering sound energy along an arbitrary convex trajectory.

    Science.gov (United States)

    Zhao, Sipei; Hu, Yuxiang; Lu, Jing; Qiu, Xiaojun; Cheng, Jianchun; Burnett, Ian

    2014-10-15

    Accelerating beams have attracted considerable research interest due to their peculiar properties and various applications. Although there have been numerous research on the generation and application of accelerating light beams, few results have been published on the generation of accelerating acoustic beams. Here we report on the experimental observation of accelerating acoustic beams along arbitrary convex trajectories. The desired trajectory is projected to the spatial phase profile on the boundary which is discretized and sampled spatially. The sound field distribution is formulated with the Green function and the integral equation method. Both the paraxial and the non-paraxial regimes are examined and observed in the experiments. The effect of obstacle scattering in the sound field is also investigated and the results demonstrate that the approach is robust against obstacle scattering. The realization of accelerating acoustic beams will have an impact on various applications where acoustic information and energy are required to be delivered along an arbitrary convex trajectory.

  5. What is mechanical energy ?

    CERN Document Server

    Heitkamp, Kristina Lyn

    2017-01-01

    Energy is everywhere. Introduce young readers to mechanical energy with this visually engaging text. Mechanical energy is defined through accessible language, explaining basic concepts such as potential and kinetic energy. Learn how mechanical energy has been harnessed in inventive ways over the course of history. Readers discover different sources of mechanical energy and how it can be transformed through real-world examples. The text also shares opportunities to observe and measure mechanical energy in the classroom and beyond, and it features questions that encourage the reader to investigate the topic further.

  6. Gender as a factor in delivering sustainable energy

    NARCIS (Netherlands)

    Clancy, Joy S.; Islam, A.K.M.S.; Infield, D.G.

    2002-01-01

    This paper reviews the role of energy in contributing to the solution of a major development objective: moving people out of poverty. Understanding gender issues, especially the crucial role women play in household energy provision, is important in the design and implementation of appropriate energy

  7. Gender as a factor in delivering sustainable energy

    NARCIS (Netherlands)

    Clancy, J.S.; Islam, A.K.M.S.; Infield, D.G.

    2002-01-01

    This paper reviews the role of energy in contributing to the solution of a major development objective: moving people out of poverty. Understanding gender issues, especially the crucial role women play in household energy provision, is important in the design and implementation of appropriate energy

  8. BIOMASS TO ENERGY IN THE SOUTHERN UNITED STATES: SUPPLY CHAIN AND DELIVERED COST

    Directory of Open Access Journals (Sweden)

    Ronalds W. Gonzalez

    2011-06-01

    Full Text Available Supply chain and delivered cost models for seven feedstocks (loblolly pine, Eucalyptus, natural hardwood, switchgrass, Miscanthus, sweet sorghum, and corn stover were built, simulating a supply of 453,597 dry tons per year to a biorefinery. Delivered cost of forest-based feedstocks ranged from $69 to $71 per dry ton. On the other hand, delivered cost of agricultural biomass ranged from $77.60 to $102.50 per dry ton. The total production area required for fast growing feedstocks was estimated as between 22,500 to 27,000 hectares, while the total production area for feedstocks with lower biomass productivity ranged from 101,200 to 202,300 hectares (corn stover and natural hardwood, respectively. Lower delivered cost per ton of carbohydrate and million BTU were found for loblolly pine, Eucalyptus, and natural hardwood. In addition, agricultural biomass had higher delivered costs for carbohydrate and energy value.

  9. Waste energy harvesting mechanical and thermal energies

    CERN Document Server

    Ling Bing, Kong; Hng, Huey Hoon; Boey, Freddy; Zhang, Tianshu

    2014-01-01

    Waste Energy Harvesting overviews the latest progress in waste energy harvesting technologies, with specific focusing on waste thermal mechanical energies. Thermal energy harvesting technologies include thermoelectric effect, storage through phase change materials and pyroelectric effect. Waste mechanical energy harvesting technologies include piezoelectric (ferroelectric) effect with ferroelectric materials and nanogenerators. The book aims to strengthen the syllabus in energy, materials and physics and is well suitable for students and professionals in the fields.

  10. Method and apparatus for delivering high power laser energy over long distances

    Energy Technology Data Exchange (ETDEWEB)

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2015-04-07

    Systems, devices and methods for the transmission and delivery of high power laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

  11. Method and apparatus for delivering high power laser energy over long distances

    Energy Technology Data Exchange (ETDEWEB)

    Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

    2013-08-20

    Systems, devices and methods for the transmission of 1 kW or more of laser energy deep into the earth and for the suppression of associated nonlinear phenomena. Systems, devices and methods for the laser drilling of a borehole in the earth. These systems can deliver high power laser energy down a deep borehole, while maintaining the high power to advance such boreholes deep into the earth and at highly efficient advancement rates.

  12. Kagome fiber based ultrafast laser microsurgery probe delivering micro-Joule pulse energies.

    Science.gov (United States)

    Subramanian, Kaushik; Gabay, Ilan; Ferhanoğlu, Onur; Shadfan, Adam; Pawlowski, Michal; Wang, Ye; Tkaczyk, Tomasz; Ben-Yakar, Adela

    2016-11-01

    We present the development of a 5 mm, piezo-actuated, ultrafast laser scalpel for fast tissue microsurgery. Delivery of micro-Joules level energies to the tissue was made possible by a large, 31 μm, air-cored inhibited-coupling Kagome fiber. We overcome the fiber's low NA by using lenses made of high refractive index ZnS, which produced an optimal focusing condition with 0.23 NA objective. The optical design achieved a focused laser spot size of 4.5 μm diameter covering a 75 × 75 μm(2) scan area in a miniaturized setting. The probe could deliver the maximum available laser power, achieving an average fluence of 7.8 J/cm(2) on the tissue surface at 62% transmission efficiency. Such fluences could produce uninterrupted, 40 μm deep cuts at translational speeds of up to 5 mm/s along the tissue. We predicted that the best combination of speed and coverage exists at 8 mm/s for our conditions. The onset of nonlinear absorption in ZnS, however, limited the probe's energy delivery capabilities to 1.4 μJ for linear operation at 1.5 picosecond pulse-widths of our fiber laser. Alternatives like broadband CaF2 crystals should mitigate such nonlinear limiting behavior. Improved opto-mechanical design and appropriate material selection should allow substantially higher fluence delivery and propel such Kagome fiber-based scalpels towards clinical translation.

  13. Kagome fiber based ultrafast laser microsurgery probe delivering micro-Joule pulse energies

    Science.gov (United States)

    Subramanian, Kaushik; Gabay, Ilan; Ferhanoğlu, Onur; Shadfan, Adam; Pawlowski, Michal; Wang, Ye; Tkaczyk, Tomasz; Ben-Yakar, Adela

    2016-01-01

    We present the development of a 5 mm, piezo-actuated, ultrafast laser scalpel for fast tissue microsurgery. Delivery of micro-Joules level energies to the tissue was made possible by a large, 31 μm, air-cored inhibited-coupling Kagome fiber. We overcome the fiber’s low NA by using lenses made of high refractive index ZnS, which produced an optimal focusing condition with 0.23 NA objective. The optical design achieved a focused laser spot size of 4.5 μm diameter covering a 75 × 75 μm2 scan area in a miniaturized setting. The probe could deliver the maximum available laser power, achieving an average fluence of 7.8 J/cm2 on the tissue surface at 62% transmission efficiency. Such fluences could produce uninterrupted, 40 μm deep cuts at translational speeds of up to 5 mm/s along the tissue. We predicted that the best combination of speed and coverage exists at 8 mm/s for our conditions. The onset of nonlinear absorption in ZnS, however, limited the probe’s energy delivery capabilities to 1.4 μJ for linear operation at 1.5 picosecond pulse-widths of our fiber laser. Alternatives like broadband CaF2 crystals should mitigate such nonlinear limiting behavior. Improved opto-mechanical design and appropriate material selection should allow substantially higher fluence delivery and propel such Kagome fiber-based scalpels towards clinical translation. PMID:27896003

  14. Energy Management in Small Commercial Buildings: A Look at How HVAC Contractors Can Deliver Energy Efficiency to this Segment

    Energy Technology Data Exchange (ETDEWEB)

    Hult, Erin; Granderson, Jessica; Mathew, Paul

    2014-07-01

    While buildings smaller than 50,000 sq ft account for nearly half of the energy used in US commercial buildings, energy efficiency programs to-date have primarily focused on larger buildings. Interviews with stakeholders and a review of the literature indicate interest in energy efficiency from the small commercial building sector, provided solutions are simple and low-cost. An approach to deliver energy management to small commercial buildings via HVAC contractors and preliminary demonstration findings are presented. The energy management package (EMP) developed includes five technical elements: benchmarking and analysis of monthly energy use; analysis of interval electricity data (if available), a one-hour onsite walkthrough, communication with the building owner, and checking of results. This data-driven approach tracks performance and identifies low-cost opportunities, using guidelines and worksheets for each element to streamline the delivery process and minimize the formal training required. This energy management approach is unique from, but often complementary to conventional quality maintenance or retrofit-focused programs targeting the small commercial segment. Because HVAC contractors already serve these clients, the transaction cost to market and deliver energy management services can be reduced to the order of hundreds of dollars per year. This business model, outlined briefly in this report, enables the offering to benefit the contractor and client even at the modest expected energy savings in small buildings. Results from a small-scale pilot of this approach validated that the EMP could be delivered by contractors in 4-8 hours per building per year, and that energy savings of 3-5percent are feasible through this approach.

  15. Solar power satellites: our next generation of satellites will deliver the sun's energy to Earth

    Science.gov (United States)

    Flournoy, Don M.

    2009-12-01

    The paper addresses the means for gathering energy from sunlight in space and transmitting it to Earth via Solar Power Satellites. The motivating factor is that the output of our sun is the largest potential energy source available, with the capability of providing inexhaustible quantities of clean electrical energy to every location on Earth. The challenge is that considerable financial, intellectual and diplomatic resources must be focused on designing and implementing new types of energy infrastructures in space and on the ground. These include: 1) next-generation space platforms, arrays, and power transmission systems; 2) more flexible and powerful launch vehicles for delivering materials to space; 3) specialized receivers, converters and storage systems on earth, and the in-orbit position allocations, spectrum and software that make these systems work together efficiently and safely.

  16. Low-energy mechanical ventilation

    DEFF Research Database (Denmark)

    Andersen, Claus Wessel; Hviid, Christian Anker

    2014-01-01

    and with as little energy consumption as 41.1 kWh/m2/year including heating and all building services with no use of renewable energy such as PVcells or solar heating. One of the key means of reaching the objectives was to implement mechanical ventilation with low pressure loss and therefore low energy consumption....... The project consists of two buildings, building one is 6 stories high, and building two is 4 stories high. The buildings have a gross area of 50,500 m2 including underground parking. The ventilation and indoor climate concept was to use mechanical ventilation together with mechanical cooling and fanassisted...

  17. Using Information Processing Techniques to Forecast, Schedule, and Deliver Sustainable Energy to Electric Vehicles

    Science.gov (United States)

    Pulusani, Praneeth R.

    As the number of electric vehicles on the road increases, current power grid infrastructure will not be able to handle the additional load. Some approaches in the area of Smart Grid research attempt to mitigate this, but those approaches alone will not be sufficient. Those approaches and traditional solution of increased power production can result in an insufficient and imbalanced power grid. It can lead to transformer blowouts, blackouts and blown fuses, etc. The proposed solution will supplement the ``Smart Grid'' to create a more sustainable power grid. To solve or mitigate the magnitude of the problem, measures can be taken that depend on weather forecast models. For instance, wind and solar forecasts can be used to create first order Markov chain models that will help predict the availability of additional power at certain times. These models will be used in conjunction with the information processing layer and bidirectional signal processing components of electric vehicle charging systems, to schedule the amount of energy transferred per time interval at various times. The research was divided into three distinct components: (1) Renewable Energy Supply Forecast Model, (2) Energy Demand Forecast from PEVs, and (3) Renewable Energy Resource Estimation. For the first component, power data from a local wind turbine, and weather forecast data from NOAA were used to develop a wind energy forecast model, using a first order Markov chain model as the foundation. In the second component, additional macro energy demand from PEVs in the Greater Rochester Area was forecasted by simulating concurrent driving routes. In the third component, historical data from renewable energy sources was analyzed to estimate the renewable resources needed to offset the energy demand from PEVs. The results from these models and components can be used in the smart grid applications for scheduling and delivering energy. Several solutions are discussed to mitigate the problem of overloading

  18. Increasing self-regulatory energy using an Internet-based training application delivered by smartphone technology.

    Science.gov (United States)

    Cranwell, Jo; Benford, Steve; Houghton, Robert J; Golembewski, Michael; Golembewksi, Michael; Fischer, Joel E; Hagger, Martin S

    2014-03-01

    Self-control resources can be defined in terms of "energy." Repeated attempts to override desires and impulses can result in a state of reduced self-control energy termed "ego depletion" leading to a reduced capacity to regulate future self-control behaviors effectively. Regular practice or "training" on self-control tasks may improve an individual's capacity to overcome ego depletion effectively. The current research tested the effectiveness of training using a novel Internet-based smartphone application to improve self-control and reduce ego depletion. In two experiments, participants were randomly assigned to either an experimental group, which received a daily program of self-control training using a modified Stroop-task Internet-based application delivered via smartphone to participants over a 4-week period, or a no-training control group. Participants assigned to the experimental group performed significantly better on post-training laboratory self-control tasks relative to participants in the control group. Findings support the hypothesized training effect on self-control and highlight the effectiveness of a novel Internet-based application delivered by smartphone as a practical means to administer and monitor a self-control training program. The smartphone training application has considerable advantages over other means to train self-control adopted in previous studies in that it has increased ecological validity and enables effective monitoring of compliance with the training program.

  19. Prospects of concentrating solar power to deliver key energy services in a developing country

    Directory of Open Access Journals (Sweden)

    Charikleia Karakosta, Charalampos Pappas, John Psarras

    2011-09-01

    Full Text Available One of today's greatest challenges is the response to the worldwide continuously increasing energy demand. The need for supply of electricity is getting greater year by year. In addition, climate change problems and the limited fossil resources require new sustainable electricity generation options, which utilize Renewable Energy Sources (RES and are economical in the meantime. Concentrating Solar Power (CSP generation is a proven renewable energy technology that has the potential to become cost-effective in the future. This analysis explores for Chile the potential of CSP to deliver key energy services for the country. The specific technology has a significant technical potential within Chile, but ‘somehow’ do not receive sufficient attention from relevant stakeholders, because of gaps either in stakeholders awareness of the technology or in domestic research and development and/or public/private investment. The aim of this paper is to establish a well-informed discussion on the feasibility and potential of the specific sustainable energy technology, namely the CSP technology, within a given country context and particularly Chile. It provides an overview of the fundamental (macro-economic forces within an economy and identifies some of the blockages and barriers that can be expected when introducing a new technology.

  20. Application of laser pulse stretching scheme for efficiently delivering laser energy in photoacoustic imaging

    Science.gov (United States)

    Wang, Tianheng; Kumavor, Patrick D.; Zhu, Quing

    2012-06-01

    High-energy and short-duration laser pulses are desirable to improve the photoacoustic image quality when imaging deeply seated lesions. In many clinical applications, the high-energy pulses are coupled to tissue using optical fibers. These pulses can damage fibers if the damage threshold is exceeded. While keeping the total energy under the Food and Drug Administration limit for avoiding tissue damage, it is necessary to reduce the peak intensity and increase the pulse duration for minimizing fiber damage and delivering sufficient light for imaging. We use laser-pulse-stretching to address this problem. An initial 17-ns pulse was stretched to 27 and 37 ns by a ring-cavity laser-pulse-stretching system. The peak power of the 37-ns stretched pulse reduced to 42% of the original, while the fiber damage threshold was increased by 1.5-fold. Three ultrasound transducers centered at 1.3-, 3.5-, and 6-MHz frequencies were simulated, and the results showed that the photoacoustic signal of a 0.5-mm-diameter target obtained with 37-ns pulse was about 98, 91, and 80%, respectively, using the same energy as the 17-ns pulse. Simulations were validated using a broadband hydrophone. Quantitative comparisons of photoacoustic images obtained with three corresponding transducers showed that the image quality was not affected by stretching the pulse.

  1. Energy Saving Recommended: Delivering improved product standards, market presence and quality

    Energy Technology Data Exchange (ETDEWEB)

    Lock, Tom; Galvanoni, Frances [Energy Saving Trust (United Kingdom)

    2007-07-01

    CO{sub 2} emissions from the home equate to 27 % of UK total emissions. In order for consumers to use less energy, and reduce their environmental impact, the Energy Saving Recommended (ESR) voluntary product labelling scheme for domestic energy saving products was established to direct the consumer to choose better products and make smarter choices. With over 2000 certified products, ESR is present across 5 sectors and covers 24 product categories; 9 sets of standards were reviewed and revised in 2005/6 and a further 13 were delivered in 2006/7. ESR is now implementing existing and developing new standards in consumer electronics - from integrated digital televisions and recorders, to intelligent mains sockets and set-top-boxes, as well as assessing the feasibility of endorsing domestic ICT equipment. The Energy Saving Trust, through its marketing activities, acts as an enabler to make energy saving action simpler, easier and cheaper for the consumer to undertake. Using a variety of communication strategies the trade is engaged through the provision of value added member benefits; a holistic approach is taken with key partners to integrate energy efficiency throughout their businesses. Merchandising support helps product standards to be implemented in the market place; evaluation and research work demonstrates that markets can be changed and shows a 1 in 3 label recognition rate. The credibility and integrity of the label are reinforced through compliance testing, in-store and online label monitoring and legal enforcement, frequent data checks and the integration of ISO best practice standards through the certification system.

  2. Delivering organisational adaptation through legislative mechanisms: Evidence from the Adaptation Reporting Power (Climate Change Act 2008).

    Science.gov (United States)

    Jude, S R; Drew, G H; Pollard, S J T; Rocks, S A; Jenkinson, K; Lamb, R

    2017-01-01

    There is increasing recognition that organisations, particularly in key infrastructure sectors, are potentially vulnerable to climate change and extreme weather events, and require organisational responses to ensure they are resilient and adaptive. However, detailed evidence of how adaptation is facilitated, implemented and reported, particularly through legislative mechanisms is lacking. The United Kingdom Climate Change Act (2008), introduced the Adaptation Reporting Power, enabling the Government to direct so-called reporting authorities to report their climate change risks and adaptation plans. We describe the authors' unique role and experience supporting the Department for Environment, Food and Rural Affairs (Defra) during the Adaptation Reporting Power's first round. An evaluation framework, used to review the adaptation reports, is presented alongside evidence on how the process provides new insights into adaptation activities and triggered organisational change in 78% of reporting authorities, including the embedding of climate risk and adaptation issues. The role of legislative mechanisms and risk-based approaches in driving and delivering adaptation is discussed alongside future research needs, including the development of organisational maturity models to determine resilient and well adapting organisations. The Adaptation Reporting Power process provides a basis for similar initiatives in other countries, although a clear engagement strategy to ensure buy-in to the process and research on its long-term legacy, including the potential merits of voluntary approaches, is required. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Modelling the Contribution of Domestic Heat Pumps to Delivering UK Energy Policy Objectives

    Directory of Open Access Journals (Sweden)

    Paul Rowley

    2013-03-01

    Full Text Available The UK Government has ambitious targets for CO2 emissions reductions, particularly for the domestic housing stock. One technology that is expected to contribute significantly is heat pumps, both air and ground source. However, recent field trial results suggest that heat pumps in the UK are not delivering to performance expectations. This paper looks at the implications of these results for the UK housing stock’s future CO2 emissions. The English Housing Condition Survey dataset is used as the basis for a Monte Carlo simulation in order to model CO2 emissions and energy consumption for the whole of English housing stock out to 2050. The results suggest that, given the current UK electricity grid CO2 emission factor, in the short term poor heat pump performance could lead to a rise in emissions where natural gas boilers are displaced. In the longer term, heat pumps can realise emissions reductions when installed at high penetration levels when combined with a grid decarbonisation strategy. Until grid decarbonisation occurs, an alternative phased strategy is proposed that includes phased replacement of resistive electric heating, first in households in fuel poverty and then the remainder of properties with this heating type. Following this phased strategy, real emissions savings are possible along with a potential reduction in fuel poverty.

  4. Guide to Setting Thermal Comfort Criteria and Minimizing Energy Use in Delivering Thermal Comfort

    Energy Technology Data Exchange (ETDEWEB)

    Regnier, Cindy

    2012-08-31

    Historically thermal comfort in buildings has been controlled by simple dry bulb temperature settings. As we move into more sophisticated low energy building systems that make use of alternate systems such as natural ventilation, mixed mode system and radiant thermal conditioning strategies, a more complete understanding of human comfort is needed for both design and control. This guide will support building designers, owners, operators and other stakeholders in defining quantifiable thermal comfort parameters?these can be used to support design, energy analysis and the evaluation of the thermal comfort benefits of design strategies. This guide also contains information that building owners and operators will find helpful for understanding the core concepts of thermal comfort. Whether for one building, or for a portfolio of buildings, this guide will also assist owners and designers in how to identify the mechanisms of thermal comfort and space conditioning strategies most important for their building and climate, and provide guidance towards low energy design options and operations that can successfully address thermal comfort. An example of low energy design options for thermal comfort is presented in some detail for cooling, while the fundamentals to follow a similar approach for heating are presented.

  5. Guide to Setting Thermal Comfort Criteria and Minimizing Energy Use in Delivering Thermal Comfort

    Energy Technology Data Exchange (ETDEWEB)

    Regnier, Cindy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-08-01

    Historically thermal comfort in buildings has been controlled by simple dry bulb temperature settings. As we move into more sophisticated low energy building systems that make use of alternate systems such as natural ventilation, mixed mode system and radiant thermal conditioning strategies, a more complete understanding of human comfort is needed for both design and control. This guide will support building designers, owners, operators and other stakeholders in defining quantifiable thermal comfort parameters?these can be used to support design, energy analysis and the evaluation of the thermal comfort benefits of design strategies. This guide also contains information that building owners and operators will find helpful for understanding the core concepts of thermal comfort. Whether for one building, or for a portfolio of buildings, this guide will also assist owners and designers in how to identify the mechanisms of thermal comfort and space conditioning strategies most important for their building and climate, and provide guidance towards low energy design options and operations that can successfully address thermal comfort. An example of low energy design options for thermal comfort is presented in some detail for cooling, while the fundamentals to follow a similar approach for heating are presented.

  6. Frequency Activated Fast Power Reserve for Wind Power Plant Delivered from Stored Kinetic Energy in the Wind Turbine Inertia

    DEFF Research Database (Denmark)

    Knüppel, Thyge; Thuring, P.; Kumar, S

    2011-01-01

    is proposed that delivers a short-term power reserve from the kinetic energy in the wind turbine (WT) inertia, while considering the inherent characteristics of a wind power plant. The aim is to contribute with a fast power reserve to stabilize the frequency drop during large and sudden production deficits...

  7. Mechanisms of Light Energy Harvesting in Dendrimers and Hyperbranched Polymers

    Directory of Open Access Journals (Sweden)

    David L. Andrews

    2011-12-01

    Full Text Available Since their earliest synthesis, much interest has arisen in the use of dendritic and structurally allied forms of polymer for light energy harvesting, especially as organic adjuncts for solar energy devices. With the facility to accommodate a proliferation of antenna chromophores, such materials can capture and channel light energy with a high degree of efficiency, each polymer unit potentially delivering the energy of one photon—or more, when optical nonlinearity is involved. To ensure the highest efficiency of operation, it is essential to understand the processes responsible for photon capture and channelling of the resulting electronic excitation. Highlighting the latest theoretical advances, this paper reviews the principal mechanisms, which prove to involve a complex interplay of structural, spectroscopic and electrodynamic properties. Designing materials with the capacity to capture and control light energy facilitates applications that now extend from solar energy to medical photonics.

  8. Renewable Energy Zones: Delivering Clean Power to Meet Demand, Greening the Grid

    Energy Technology Data Exchange (ETDEWEB)

    Hurlbut, David; Chernyakhovskiy, Ilya; Cochran, Jaquelin

    2016-05-01

    Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid. This document describes the renewable energy zone concept that has emerged as a transmission planning tool to help scale up the penetration of solar, wind, and other resources on the power system.

  9. Methods and apparatus for delivering high power laser energy to a surface

    Energy Technology Data Exchange (ETDEWEB)

    Faircloth, Brian O; Zediker, Mark S; Rinzler, Charles C; Koblick, Yeshaya; Moxley, Joel F

    2013-04-23

    There is provided a system, apparatus and methods for providing a laser beam to borehole surface in a predetermined and energy deposition profile. The predetermined energy deposition profiles may be uniform or tailored to specific downhole applications. Optic assemblies for obtaining these predetermined energy deposition profiles are further provided.

  10. Field Experience from Li-Ion BESS Delivering Primary Frequency Regulation in the Danish Energy Market

    DEFF Research Database (Denmark)

    Swierczynski, Maciej Jozef; Stroe, Daniel Ioan; Lærke, Rasmus

    2014-01-01

    In this paper it is presented the practical experience from operating a 1.6 MW/ 0.4 MWh lithium ion battery energy storage system, which is providing primary frequency regulation service on the Danish energy market. Aspects of the battery system requirements and the used control strategy...

  11. NAMAs as a tool to deliver energy efficiency measures in buildings

    DEFF Research Database (Denmark)

    Karavai, Maryna; Petrichenko, Ksenia

    -makers on designing and implementing NAMAs aimed at improving energy efficiency in the building sector with a particular focus on tropical and sub-tropical climates. The paper covers the following topics: • generic background for the NAMA concept, it origin and founding principles • potential areas for NAMA...... interventions, policy and technology • technological measures in buildings in hot and humid climates • development process for policy NAMAs that aim to improve energy efficiency in buildings The paper concludes on future prospects for policy NAMAs related to energy efficient buildings and the necessary actions...... greenhouse gas emissions and transforming their development towards sustainable pathways. One of the sectors, which offer significant mitigation potential in developing countries, is the building sector; especially taking into account rapid urbanisation, increase in access to energy, population and economic...

  12. Energy Harvesting By Optimized Piezo Transduction Mechanism

    CERN Document Server

    Boban, Bijo; Satheesh, U; Devaprakasam, D

    2014-01-01

    We report generation of electrical energy from nonlinear mechanical noises available in the ambient environment using optimized piezo transduction mechanisms. Obtaining energy from an ambient vibration has been attractive for remotely installed standalone microsystems and devices. The mechanical noises in the ambient environment can be converted to electrical energy by a piezo strip based on the principle of piezoelectric effect. In this work, we have designed and developed a standalone energy harvesting module based on piezo transduction mechanisms. Using this designed module we harvested noise energy and stored electrical energy in a capacitor. Using NI-PXI workstation with a LabVIEW programming, the output voltage of the piezo strip and voltage of the capacitor were measured and monitored. In this paper we discuss about the design, development, implementation, performance and characteristics of the energy harvesting module.

  13. Frequency Activated Fast Power Reserve for Wind Power Plant Delivered from Stored Kinetic Energy in the Wind Turbine Inertia

    DEFF Research Database (Denmark)

    Knüppel, Thyge; Thuring, P.; Kumar, S

    2011-01-01

    With increased penetration of converter interfaced generation, synchronous generators may start to be displaced to keep the overall power balance. As a consequence the resulting inertia in the system may decrease and make the power system more exposed to frequency excursions. Here, a control...... is proposed that delivers a short-term power reserve from the kinetic energy in the wind turbine (WT) inertia, while considering the inherent characteristics of a wind power plant. The aim is to contribute with a fast power reserve to stabilize the frequency drop during large and sudden production deficits...

  14. A SEASONAL AND MONTHLY APPROACH FOR PREDICTING THE DELIVERED ENERGY QUANTITY IN A PHOTOVOLTAIC POWER PLANT IN ROMANIA

    Directory of Open Access Journals (Sweden)

    George Căruțașu

    2016-12-01

    Full Text Available In this paper, we present solutions that facilitate the forecasting of the delivered energy quantity in a photovoltaic power plant using the data measured from the solar panels' sensors: solar irradiation level, present module temperature, environmental temperature, atmospheric pressure and humidity. We have developed and analyzed a series of Artificial Neural Networks (ANNs based on the Levenberg-Marquardt algorithm, using seasonal and monthly approaches. We have also integrated our developed Artificial Neural Networks into callable functions that we have compiled using the Matlab Compiler SDK. Thus, our solution can be accessed by developers through multiple Application Programming Interfaces when programming software that predicts the photovoltaic renewable energy production considering the seasonal particularities of the Romanian weather patterns

  15. Electrochemical to Mechanical Energy Conversion

    Science.gov (United States)

    2010-02-01

    10 mAh) showing the principal curvature axis of larger curvature. Significant permanent damage is seen on the top surface where the lithium...capacity of 10 mAh) showing the principal curvature axis of larger curvature. Significant permanent damage is seen on the top surface where the lithium...the Mechanics and Physics of Solids 48, 1159- 1174(2000). 5. Giannakopoulos, A. et al. Elastoplastic analysis of thermal cycling: layered materials

  16. Methodologies of Measuring Mechanical Power Delivered at the Shaft of an Induction Motor Driven by VFD

    Directory of Open Access Journals (Sweden)

    Mariana MANEA

    2012-12-01

    Full Text Available Measuring precise power used by a load of an induction motor driven by a VFD implies a few facts that need to be considered. First, the real electric power. When dealing with waveforms of electric current that contain harmonics, traditional methods of power measuring could lead to inaccurate results. Therefore, further investigation needs to be performed in order to provide meaningful values. Then there is the efficiency. Motor losses are to be taken into account for finding out exactly how much power is being used for a specific application.This paper shows a method of measuring and calculating the electric real power of fundamental harmonic and of extracting an actual output value of mechanical power at the motor shaft. For this purpose we used a data acquisition system made of a basic power quality analyzer and data acquisition software. Harmonic analysis of the waveforms is considered, combined with the use of the true power factor.

  17. ‘Command Without Control’: Are Market Mechanisms Capable of Delivering Ecological Integrity to REDD?

    Directory of Open Access Journals (Sweden)

    Simon West

    2010-12-01

    Full Text Available Market mechanisms have been increasingly touted over the last 40 years as the most ecologically effective and economically efficient way to solve environmental problems. The problem of deforestation has been increasingly recognised in the climate change regime over the last 15 years as a major source of greenhouse gas emissions. Correspondingly many politicians, academics and commentators believe that linking forestry conservation projects to international carbon markets is potentially a cost-efficient way of reducing emissions and stabilising temperature rise below two degrees Celsius. This belief has been translated into a broad set of policy proposals generally named REDD (reducing emissions from deforestation and forest degradation. This paper will assess whether a market-linked REDD programme is in fact capable of preventing deforestation efficiently and within the timescale needed. The history of forestry activities within the climate regime will be outlined, before proposals for a market-linked REDD are analysed in the context of contemporary academic discourse and in the context of ‘real-world’ experience. The ability of a market-linked REDD mechanism to ensure adequate measurement, reporting and verification (MRV, land tenure, public participation, and public-private interaction is questioned. Indeed, the paper concludes by suggesting that the lessons drawn from studying previous market-linked schemes for environmental protection indicate that a market-linked REDD scheme will not achieve the desired reductions in greenhouse gasses in the timescale required, and could in fact be an expensive distraction from other simpler and faster methods of carbon reduction.

  18. A mechanical energy analysis of gait initiation

    Science.gov (United States)

    Miller, C. A.; Verstraete, M. C.

    1999-01-01

    The analysis of gait initiation (the transient state between standing and walking) is an important diagnostic tool to study pathologic gait and to evaluate prosthetic devices. While past studies have quantified mechanical energy of the body during steady-state gait, to date no one has computed the mechanical energy of the body during gait initiation. In this study, gait initiation in seven normal male subjects was studied using a mechanical energy analysis to compute total body energy. The data showed three separate states: quiet standing, gait initiation, and steady-state gait. During gait initiation, the trends in the energy data for the individual segments were similar to those seen during steady-state gait (and in Winter DA, Quanbury AO, Reimer GD. Analysis of instantaneous energy of normal gait. J Biochem 1976;9:253-257), but diminished in amplitude. However, these amplitudes increased to those seen in steady-state during the gait initiation event (GIE), with the greatest increase occurring in the second step due to the push-off of the foundation leg. The baseline level of mechanical energy was due to the potential energy of the individual segments, while the cyclic nature of the data was indicative of the kinetic energy of the particular leg in swing phase during that step. The data presented showed differences in energy trends during gait initiation from those of steady state, thereby demonstrating the importance of this event in the study of locomotion.

  19. Monte Carlo simulation to evaluate the contamination in an energy modulated carbon ion beam for hadron therapy delivered by cyclotron.

    Science.gov (United States)

    Morone, M Cristina; Calabretta, Luciano; Cuttone, Giacomo; Fiorini, Francesca

    2008-11-07

    Protons and carbon ion beams for hadron therapy can be delivered by cyclotrons with a fixed energy. In order to treat patients, an energy degrader along the beam line will be used to match the particle range with the target depth. Fragmentation reactions of carbon ions inside the degrader material could introduce a small amount of unwanted contaminants to the beam, giving additional dose to the patient out of the target volume. A simulation study using the FLUKA Monte Carlo code has been carried out by considering three different materials as the degrader. Two situations have been studied: a realistic one, lowering the carbon beam energy from 300 MeV/n to 220 MeV/n, corresponding to a range of 10 cm in water, and the worst possible case, lowering the carbon energy to 50 MeV/n, corresponding to the millimeter range. The main component of the contaminant is represented by alpha particles and protons, with a typical momentum after the degrader greater than that of the primary beam, and can be eliminated by the action of a momentum analyzing system and slits, and by a second thin absorber. The residual component of fragments reaching the patient is negligible with respect to the fragment quantity generated by the primary beam inside the patient before arriving at the end of the target volume.

  20. Quantum mechanical theory behind "dark energy"?

    CERN Multimedia

    Colin Johnson, R

    2007-01-01

    "The mysterious increase in the acceleration of the universe, when intuition says it should be slowing down, is postulated to be caused by dark energy - "dark" because it is undetected. Now a group of scientists in the international collaboration Essence has suggested that a quantum mechanical interpretation of Einstein's proposed "cosmological constant" is the simplest explanation for dark energy. The group measured dark energy to within 10 percent." (1,5 page)

  1. Falsification of dark energy by fluid mechanics

    OpenAIRE

    Carl H. Gibson

    2012-01-01

    The 2011 Nobel Prize in Physics was awarded for the discovery of accelerating supernovae dimness, suggesting a remarkable change in the expansion rate of the Universe from a decrease since the big bang to an increase, driven by anti-gravity forces of a mysterious dark energy material comprising 70% of the Universe mass-energy. Fluid mechanical considerations falsify both the accelerating expansion and dark energy concepts. Kinematic viscosity is neglected in current standard models of self-gr...

  2. A narrow-band wavelength-tunable laser system delivering high-energy 300 ps pulses in the near-infrared

    NARCIS (Netherlands)

    Brandi, F.; Velchev, I.; Neshev, D.; Hogervorst, W.; Ubachs, W.M.G.

    2003-01-01

    We report on the operation of a novel laser system delivering high-energy pulses in the near-infrared region. The pulses are nearly Fourier-transform limited (time-bandwidth product of 0.48), providing narrow-band radiation (similar to1.5 GHz), with an energy of 225 mJ and 10 Hz repetition rate. The

  3. Mechanical Energy Changes in Perfectly Inelastic Collisions

    Science.gov (United States)

    Mungan, Carl E.

    2013-01-01

    Suppose a block of mass "m"[subscript 1] traveling at speed "v"[subscript 1] makes a one-dimensional perfectly inelastic collision with another block of mass "m"[subscript 2]. What else does one need to know to calculate the fraction of the mechanical energy that is dissipated in the collision? (Contains 1 figure.)

  4. Mechanical Energy Change in Inertial Reference Frames

    Science.gov (United States)

    Ghanbari, Saeed

    2016-01-01

    The mechanical energy change of a system in an inertial frame of reference equals work done by the total nonconservative force in the same frame. This relation is covariant under the Galilean transformations from inertial frame S to S', where S' moves with constant velocity relative to S. In the presence of nonconservative forces, such as normal…

  5. Mechanical Characterization of Energy Materials at DTU Energy

    DEFF Research Database (Denmark)

    Tadesse Molla, Tesfaye; Han, Li; Frandsen, Henrik Lund

    go hand in hand with understanding and improving their mechanical reliability at operational conditions. With this regard, DTU energy has a dedicated team and facilities working on characterization of metallic as well as ceramic materials used in energy conversion and storage technologies. The poster......Due to the ever growing demand for sustainable energy alternatives, increasing the efficiency as well as reliability of energy conversion and storage technologies is becoming paramount challenge for the research community in the field. To achieve this, the innovation of new material systems should...... presents the unique capabilities in the department including high throughput and high temperature strength and deformational behavior characterization of materials in a controlled atmosphere. The characterization techniques mainly focus on materials being developed to be used in solid oxide fuel...

  6. Falsification of dark energy by fluid mechanics

    CERN Document Server

    Gibson, Carl H

    2012-01-01

    The 2011 Nobel Prize in Physics was awarded for the discovery of accelerating supernovae dimness, suggesting a remarkable change in the expansion rate of the Universe from a decrease since the big bang to an increase, driven by anti-gravity forces of a mysterious dark energy material comprising 70% of the Universe mass-energy. Fluid mechanical considerations falsify both the accelerating expansion and dark energy concepts. Kinematic viscosity is neglected in current standard models of self-gravitational structure formation, which rely on cold dark matter CDM condensations and clusterings that are also falsified by fluid mechanics. Weakly collisional CDM particles do not condense but diffuse away. Photon viscosity predicts superclustervoid fragmentation early in the plasma epoch and protogalaxies at the end. At the plasma-gas transition, the plasma fragments into Earth-mass gas planets in trillion planet clumps (proto-globular-star-cluster PGCs). The hydrogen planets freeze to form the dark matter of galaxies ...

  7. Aftershock Energy Distribution by Statistical Mechanics Approach

    Science.gov (United States)

    Daminelli, R.; Marcellini, A.

    2015-12-01

    The aim of our work is to research the most probable distribution of the energy of aftershocks. We started by applying one of the fundamental principles of statistical mechanics that, in case of aftershock sequences, it could be expressed as: the greater the number of different ways in which the energy of aftershocks can be arranged among the energy cells in phase space the more probable the distribution. We assume that each cell in phase space has the same possibility to be occupied, and that more than one cell in the phase space can have the same energy. Seeing that seismic energy is proportional to products of different parameters, a number of different combinations of parameters can produce different energies (e.g., different combination of stress drop and fault area can release the same seismic energy). Let us assume that there are gi cells in the aftershock phase space characterised by the same energy released ɛi. Therefore we can assume that the Maxwell-Boltzmann statistics can be applied to aftershock sequences with the proviso that the judgment on the validity of this hypothesis is the agreement with the data. The aftershock energy distribution can therefore be written as follow: n(ɛ)=Ag(ɛ)exp(-βɛ)where n(ɛ) is the number of aftershocks with energy, ɛ, A and β are constants. Considering the above hypothesis, we can assume g(ɛ) is proportional to ɛ. We selected and analysed different aftershock sequences (data extracted from Earthquake Catalogs of SCEC, of INGV-CNT and other institutions) with a minimum magnitude retained ML=2 (in some cases ML=2.6) and a time window of 35 days. The results of our model are in agreement with the data, except in the very low energy band, where our model resulted in a moderate overestimation.

  8. Power Generation Using Mechanical Wave Energy Converter

    Directory of Open Access Journals (Sweden)

    Srinivasan Chandrasekaran

    2012-03-01

    Full Text Available Ocean wave energy plays a significant role in meeting the growing demand of electric power. Economic, environmental, and technical advantages of wave energy set it apart from other renewable energy resources. Present study describes a newly proposed Mechanical Wave Energy Converter (MEWC that is employed to harness heave motion of floating buoy to generate power. Focus is on the conceptual development of the device, illustrating details of component level analysis. Employed methodology has many advantages such as i simple and easy fabrication; ii easy to control the operations during rough weather; and iii low failure rate during normal sea conditions. Experimental investigations carried out on the scaled model of MWEC show better performance and its capability to generate power at higher efficiency in regular wave fields. Design Failure Mode and Effect Analysis (FMEA shows rare failure rates for all components except the floating buoy.

  9. Mechanical vibration to electrical energy converter

    Science.gov (United States)

    Kellogg, Rick Allen; Brotz, Jay Kristoffer

    2009-03-03

    Electromechanical devices that generate an electrical signal in response to an external source of mechanical vibrations can operate as a sensor of vibrations and as an energy harvester for converting mechanical vibration to electrical energy. The devices incorporate a magnet that is movable through a gap in a ferromagnetic circuit, wherein a coil is wound around a portion of the ferromagnetic circuit. A flexible coupling is used to attach the magnet to a frame for providing alignment of the magnet as it moves or oscillates through the gap in the ferromagnetic circuit. The motion of the magnet can be constrained to occur within a substantially linear range of magnetostatic force that develops due to the motion of the magnet. The devices can have ferromagnetic circuits with multiple arms, an array of magnets having alternating polarity and, encompass micro-electromechanical (MEM) devices.

  10. Quantum mechanics/molecular mechanics dual Hamiltonian free energy perturbation.

    Science.gov (United States)

    Polyak, Iakov; Benighaus, Tobias; Boulanger, Eliot; Thiel, Walter

    2013-08-14

    The dual Hamiltonian free energy perturbation (DH-FEP) method is designed for accurate and efficient evaluation of the free energy profile of chemical reactions in quantum mechanical/molecular mechanical (QM/MM) calculations. In contrast to existing QM/MM FEP variants, the QM region is not kept frozen during sampling, but all degrees of freedom except for the reaction coordinate are sampled. In the DH-FEP scheme, the sampling is done by semiempirical QM/MM molecular dynamics (MD), while the perturbation energy differences are evaluated from high-level QM/MM single-point calculations at regular intervals, skipping a pre-defined number of MD sampling steps. After validating our method using an analytic model potential with an exactly known solution, we report a QM/MM DH-FEP study of the enzymatic reaction catalyzed by chorismate mutase. We suggest guidelines for QM/MM DH-FEP calculations and default values for the required computational parameters. In the case of chorismate mutase, we apply the DH-FEP approach in combination with a single one-dimensional reaction coordinate and with a two-dimensional collective coordinate (two individual distances), with superior results for the latter choice.

  11. Power flow in a small electromagnetic energy harvesting system excited by mechanical motion

    CERN Document Server

    Helseth, Lars Egil

    2014-01-01

    In this study the power flow in a coupled mechanical and electromagnetic harvesting system in presence of both positional and electrical fluctuations is analyzed. Explicit expressions for the power into and out of the mechanical and electrical parts of the system are found in the case of weak coupling, and it is shown how the power flows between the domains consistent with energy conservation. The case of thermal fluctuations is considered in particular, and use of the fluctuation-dissipation theorem explicitly demonstrates that the power delivered to the mechanical system from the electrical system is the same as the power delivered to the electrical system from the mechanical system. On the other hand, the power dissipated in the electrical circuit is not the same as the power transferred from the mechanical domain if the electrical circuit contains its own current fluctuations. The electrical noise power dissipated in a load resistor is calculated, and found to consist of a component due to electromagnetic...

  12. The Dark Energy Spectroscopic Instrument (DESI) instrument mechanism control systems

    Science.gov (United States)

    Coker, Carl T.; Pappalardo, Daniel; Pogge, Richard; Martini, Paul; Derwent, Mark; O'Brien, Thomas P.; Honscheid, Klaus

    2016-08-01

    The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the Universe using the Baryon Acoustic Oscillation technique. The spectra of 40 million galaxies over 14,000 sq deg will be measured during the life of the experiment. A new prime focus corrector for the KPNO Mayall telescope will deliver light to 5,000 fiber optic positioners. The fibers in turn feed ten broad-band spectrographs. We present the design details of the instrument mechanism control systems for the spectrographs. Each spectrograph has a stand-alone mechanism control box that operates the unit's four remotely-operated mechanisms (two shutters and two Hartmannn doors), and provides a suite of temperature and humidity sensors. Each control box is highly modular, and is operated by a dedicated on-board Linux computer to provide all of the control and monitoring functions. We describe our solution for integrating a number of network-connected devices within each unit spectrograph, and describe the basic software architecture.

  13. Falsification of Dark Energy by Fluid Mechanics

    Science.gov (United States)

    Gibson, Carl H.

    2012-03-01

    The 2011 Nobel Prize in Physics was awarded for the discovery of accelerating super- novae dimness, suggesting a remarkable reversal in the expansion rate of the Universe from a decrease to an increase, driven by anti-gravity forces of a mysterious dark energy material comprising 70% of the Universe mass-energy. Fluid mechanics and Herschel- Planck-Spitzer-Hubble etc. space telescope observations falsify both the accelerating ex- pansion rate and dark energy concepts. Kinematic viscosity is neglected in models of self-gravitational structure formation. Large plasma photon viscosity predicts protosu- perclustervoid fragmentation early in the plasma epoch and protogalaxies at the end. At the plasma-gas transition, the gas protogalaxies fragment into Earth-mass rogue plan- ets in highly persistent, trillion-planet clumps (proto-globular-star-cluster PGCs). PGC planets freeze to form the dark matter of galaxies and merge to form their stars, giving the hydrogen triple-point (14 K) infrared emissions observed. Dark energy is a system- atic dimming error for Supernovae Ia caused by partially evaporated planets feeding hot white dwarf stars at the Chandrasekhar carbon limit. Planet atmospheres may or may not dim light from SNe-Ia events depending on the line of sight.

  14. Theories of Dark Energy with Screening Mechanisms

    CERN Document Server

    Khoury, Justin

    2010-01-01

    Despite the overwhelming evidence for the existence of dark energy and dark matter, their underlying fundamental physics remains unknown. This review article explores the tantalizing possibility that the dark sector includes new light degrees of freedom that mediate long-range forces on cosmological scales. To ensure consistency with laboratory and solar system tests of gravity, some screening mechanism is necessary to "hide" these degrees of freedom locally. I will focus on two broad classes of screening theories, chameleons and symmetrons, which rely respectively on the scalar field acquiring a large mass or weak coupling in the presence of large ambient matter density.

  15. Nonextensive statistical mechanics and high energy physics

    Directory of Open Access Journals (Sweden)

    Tsallis Constantino

    2014-04-01

    Full Text Available The use of the celebrated Boltzmann-Gibbs entropy and statistical mechanics is justified for ergodic-like systems. In contrast, complex systems typically require more powerful theories. We will provide a brief introduction to nonadditive entropies (characterized by indices like q, which, in the q → 1 limit, recovers the standard Boltzmann-Gibbs entropy and associated nonextensive statistical mechanics. We then present somerecent applications to systems such as high-energy collisions, black holes and others. In addition to that, we clarify and illustrate the neat distinction that exists between Lévy distributions and q-exponential ones, a point which occasionally causes some confusion in the literature, very particularly in the LHC literature

  16. Calculations of Solvation Free Energy through Energy Reweighting from Molecular Mechanics to Quantum Mechanics.

    Science.gov (United States)

    Jia, Xiangyu; Wang, Meiting; Shao, Yihan; König, Gerhard; Brooks, Bernard R; Zhang, John Z H; Mei, Ye

    2016-02-09

    In this work, the solvation free energies of 20 organic molecules from the 4th Statistical Assessment of the Modeling of Proteins and Ligands (SAMPL4) have been calculated. The sampling of phase space is carried out at a molecular mechanical level, and the associated free energy changes are estimated using the Bennett Acceptance Ratio (BAR). Then the quantum mechanical (QM) corrections are computed through the indirect Non-Boltzmann Bennett's acceptance ratio (NBB) or the thermodynamics perturbation (TP) method. We show that BAR+TP gives a minimum analytic variance for the calculated solvation free energy at the Gaussian limit and performs slightly better than NBB in practice. Furthermore, the expense of the QM calculations in TP is only half of that in NBB. We also show that defining the biasing potential as the difference of the solute-solvent interaction energy, instead of the total energy, can converge the calculated solvation free energies much faster but possibly to different values. Based on the experimental solvation free energies which have been published before, it is discovered in this study that BLYP yields better results than MP2 and some other later functionals such as B3LYP, M06-2X, and ωB97X-D.

  17. The effect of location and facility demand on the marginal cost of delivered wood chips from energy crops: A case study of the state of Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Graham, R.L.; Liu, W.; Downing, M. [Oak Ridge National Lab., TN (United States). Biofuels Feedstock Development Program; Noon, C.; Daly, M. [Univ. of Tennessee, Knoxville, TN (United States). Management Science Program; Moore, A. [Dept. of Trade and Industry, Harwell (United Kingdom). Energy Technology Support Unit

    1995-12-31

    Cost-supply curves for delivered wood chips from short rotation woody crops were calculated for 21 regularly-spaced locations spanning the state of Tennessee. These curves were used to systematically evaluate the combined effects of location and facility demand on wood chip feedstock costs in Tennessee. The cost-supply curves were developed using BRAVO, a GIS-based decision support system which calculates marginal cost of delivering wood chips to a specific location given road network maps and maps of farmgate prices and supplies of woody chips from short rotation energy crops. Marginal costs of delivered chips varied by both facility location in the state and facility demand. Marginal costs were lowest in central Tennessee unless the facility demand was greater than 2.7 million dry Mg per year (3 million dry tons per year) in which case west Tennessee was the lowest cost region. Marginal costs rose rapidly with increasing facility demand in the mountainous eastern portion of the state. Transportation costs accounted for 18 to 29% of the delivered cost and ranged between $8 and $18/dry Mg ($7 and $16/dry ton). Reducing the expected farmer participation rate from 100% to 50% or 25% dramatically raised the marginal costs of feedstock supply in the east and central regions of the state. The analysis demonstrates the need to use geographically-specific information when projecting the potential costs and supplies of biomass feedstock.

  18. Energy losses in mechanically modified bacterial magnetosomes

    Science.gov (United States)

    Molcan, Matus; Gojzewski, Hubert; Skumiel, Andrzej; Dutz, Silvio; Kovac, Jozef; Kubovcikova, Martina; Kopcansky, Peter; Vekas, Ladislau; Timko, Milan

    2016-09-01

    Magnetosomes are isolated from the Magnetospirillum magneticum strain AMB-1 bacteria. Two samples are compared: magnetosomes normally prepared of a ‘standard’ length and magnetosomes of a short length. Chains of magnetosomes are shortened by mechanical modification (cleavage) by means of sonication treatment. They represent a new geometry of magnetosomes that have not been investigated before. The effect of the sonication is analysed using transmission and electron microscopy, atomic force microscopy, and dynamic light scattering. Scanning imaging reveals three types of shortening effect in a sample of shortened magnetosomes, namely, membrane collapse, membrane destruction, and magnetosome cleavage. Dynamic light scattering shows a reduction of hydrodynamic diameter in a sample of shortened magnetosomes. The magnetic properties of magnetosomes are analysed and compared in DC and AC magnetic fields based on the evaluation of quasi-static hysteresis loops (energy losses) and calorimetric hyperthermia measurements (specific absorption rate), respectively. A sample of shortened magnetosomes behaves magnetically in a different manner, showing that both the energy loss and the specific absorption rate are reduced, and thereby indicates a variation in the heating process. The magnetic properties of magnetosomes, together with the new and stable geometry, are balanced, which opens the way for a better adaptation of the magnetic field parameters for particular applications.

  19. Energy implications of mechanical and mechanical-biological treatment compared to direct waste-to-energy.

    Science.gov (United States)

    Cimpan, Ciprian; Wenzel, Henrik

    2013-07-01

    Primary energy savings potential is used to compare five residual municipal solid waste treatment systems, including configurations with mechanical (MT) and mechanical-biological (MBT) pre-treatment, which produce waste-derived fuels (RDF and SRF), biogas and/or recover additional materials for recycling, alongside a system based on conventional mass burn waste-to-energy and ash treatment. To examine the magnitude of potential savings we consider two energy efficiency levels (state-of-the-art and best available technology), the inclusion/exclusion of heat recovery (CHP vs. PP) and three different background end-use energy production systems (coal condensing electricity and natural gas heat, Nordic electricity mix and natural gas heat, and coal CHP energy quality allocation). The systems achieved net primary energy savings in a range between 34 and 140 MJprimary/100 MJinput waste, in the different scenario settings. The energy footprint of transportation needs, pre-treatment and reprocessing of recyclable materials was 3-9.5%, 1-18% and 1-8% respectively, relative to total energy savings. Mass combustion WtE achieved the highest savings in scenarios with CHP production, nonetheless, MBT-based systems had similarly high performance if SRF streams were co-combusted with coal. When RDF and SRF was only used in dedicated WtE plants, MBT-based systems totalled lower savings due to inherent system losses and additional energy costs. In scenarios without heat recovery, the biodrying MBS-based system achieved the highest savings, on the condition of SRF co-combustion. As a sensitivity scenario, alternative utilisation of SRF in cement kilns was modelled. It supported similar or higher net savings for all pre-treatment systems compared to mass combustion WtE, except when WtE CHP was possible in the first two background energy scenarios. Recovery of plastics for recycling before energy recovery increased net energy savings in most scenario variations, over those of full

  20. The influence of home-delivered dietary approaches to stop hypertension meals on body mass index, energy intake, and percent of energy needs consumed among older adults with hypertension and/or hyperlipidemia.

    Science.gov (United States)

    Racine, Elizabeth F; Lyerly, Jordan; Troyer, Jennifer L; Warren-Findlow, Jan; McAuley, William J

    2012-11-01

    It is unclear whether participation in home-delivered meal programs similar to the Older Americans Act home-delivered meals program influence weight status among older adults with hypertension and/or hyperlipidemia. To examine the influence of a home-delivered Dietary Approaches to Stop Hypertension (DASH) meal intervention on body mass index (BMI), energy consumed, and percent of energy needs consumed. A 1-year randomized control trial of home-delivered DASH meals and medical nutrition therapy conducted from 2003 through 2005. Participants who received DASH meals were compared with those who did not receive meals. Data were collected in participants' homes at baseline, 6 months, and 12 months. The study sample was composed of 298 adults aged >60 years with hypertension and/or hyperlipidemia residing in a county in the southeastern part of North Carolina. Participants in the meals intervention group received seven frozen meals per week for 1 year. The meals were designed to meet one third of participants' energy and nutrient needs and to comply with the DASH diet. Change in BMI, energy consumed, and percent of energy needs consumed. Difference-in-differences models were used to estimate the effects of the meal intervention on BMI, energy consumed, and percent of daily energy needs consumed. Analyses were conducted among the full sample and by subgroup (ie, race, income, and baseline obesity status). In the full sample, receipt of meals did not have a significant effect on BMI, energy consumed, or percent of daily energy needs consumed. Among those living at or above the 165% poverty threshold, receipt of home-delivered meals was significantly associated with a decrease in energy consumed and, therefore, percent of daily energy needs consumed. Participation in a home-delivered DASH meal program did not lead to weight gain or weight loss in a group of mostly overweight or obese older adults with hypertension and/or hyperlidemia. Copyright © 2012 Academy of Nutrition

  1. Energy Harvesting from Mechanical Shocks Using A Sensitive Vibration Energy Harvester

    Directory of Open Access Journals (Sweden)

    Zdenek Hadas

    2012-11-01

    Full Text Available This paper deals with a unique principle of energy harvesting technologies. An energy harvesting device generates electric energy from its surroundings using some kind of energy conversion method. Therefore, the considered energy harvesting device does not consume any fuel or substance. The presented energy harvesting system is used forenergy harvesting of electrical energy from mechanical shocks. The presented energy harvesting system uses a very sensitive vibration energy harvester, which was developed for an aeronautic application at Brno University of Technology. This energy harvesting system is a complex mechatronic device, which consists of a precise mechanical part, an electromagnetic converter, power electronics (power management and a load (e.g., wireless sensor. The very sensitive vibration energy harvester is capable of usingthe mechanical energy of mechanical shocks and it can harvest useful energy. This energy harvesting system is used with a wireless temperature sensor and measured results are presented in this paper.

  2. Energy Harvesting from Mechanical Shocks Using a Sensitive Vibration Energy Harvester

    Directory of Open Access Journals (Sweden)

    Zdenek Hadas

    2012-11-01

    Full Text Available This paper deals with a unique principle of energy harvesting technologies. An energy harvesting device generates electric energy from its surroundings using some kind of energy conversion method. Therefore, the considered energy harvesting device does not consume any fuel or substance. The presented energy harvesting system is used forenergy harvesting of electrical energy from mechanical shocks. The presented energy harvesting system uses a very sensitive vibration energy harvester, which was developed for an aeronautic application at Brno University of Technology. This energy harvesting system is a complex mechatronic device, which consists of a precise mechanical part, an electromagnetic converter, power electronics (power management and a load (e.g., wireless sensor. The very sensitive vibration energy harvester is capable of usingthe mechanical energy of mechanical shocks and it can harvest useful energy. This energy harvesting system is used with a wireless temperature sensor and measured results are presented in this paper.

  3. Autonomy-oriented mechanisms for efficient energy distribution

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiming; Shi, Benyun

    2010-09-15

    Due to the uneven geographical availability of energy resources, it is essential for the energy suppliers and consumers in different countries/regions to most efficiently, economically, as well as reliably distribute energy resources. In this paper, starting from a specific energy distribution problem, we present a decentralized behavior-based paradigm that draws on the methodology of autonomy-oriented computing. The goal is twofold: (i) to characterize the underlying mechanism of the energy distribution systems, (ii) to provide scalable solutions for efficient energy distribution. We conjecture that efficient energy trading markets can emerge from appropriate behavior-based mechanisms, which can autonomously improve energy distribution efficiency.

  4. Food and nutritional security requires adequate protein as well as energy, delivered from whole-year crop production

    DEFF Research Database (Denmark)

    Coles, Graeme D; Wratten, Stephen D; Porter, John Roy

    2016-01-01

    Human food security requires the production of sufficient quantities of both high-quality protein and dietary energy. In a series of case-studies from New Zealand, we show that while production of food ingredients from crops on arable land can meet human dietary energy requirements effectively......, requirements for high-quality protein are met more efficiently by animal production from such land. We present a model that can be used to assess dietary energy and quality-corrected protein production from various crop and crop/animal production systems, and demonstrate its utility. We extend our analysis...... with an accompanying economic analysis of commercially-available, pre-prepared or simply-cooked foods that can be produced from our case-study crop and animal products. We calculate the per-person, per-day cost of both quality-corrected protein and dietary energy as provided in the processed foods. We conclude...

  5. Food and nutritional security requires adequate protein as well as energy, delivered from whole-year crop production

    DEFF Research Database (Denmark)

    Coles, Graeme D; Wratten, Stephen D; Porter, John Roy

    2016-01-01

    Human food security requires the production of sufficient quantities of both high-quality protein and dietary energy. In a series of case-studies from New Zealand, we show that while production of food ingredients from crops on arable land can meet human dietary energy requirements effectively......, requirements for high-quality protein are met more efficiently by animal production from such land. We present a model that can be used to assess dietary energy and quality-corrected protein production from various crop and crop/animal production systems, and demonstrate its utility. We extend our analysis...... with an accompanying economic analysis of commercially-available, pre-prepared or simply-cooked foods that can be produced from our case-study crop and animal products. We calculate the per-person, per-day cost of both quality-corrected protein and dietary energy as provided in the processed foods. We conclude...

  6. Energy Harvesting from Mechanical Shocks Using A Sensitive Vibration Energy Harvester

    OpenAIRE

    Zdenek Hadas; Vojtech Vetiska; Vladislav Singule; Ondrej Andrs; Jiri Kovar; Jan Vetiska

    2012-01-01

    This paper deals with a unique principle of energy harvesting technologies. An energy harvesting device generates electric energy from its surroundings using some kind of energy conversion method. Therefore, the considered energy harvesting device does not consume any fuel or substance. The presented energy harvesting system is used forenergy harvesting of electrical energy from mechanical shocks. The presented energy harvesting system uses a very sensitive vibration energy harvester, which w...

  7. Energy Harvesting from Mechanical Shocks Using A Sensitive Vibration Energy Harvester

    OpenAIRE

    Zdenek Hadas; Vojtech Vetiska; Vladislav Singule; Ondrej Andrs; Jiri Kovar; Jan Vetiska

    2012-01-01

    This paper deals with a unique principle of energy harvesting technologies. An energy harvesting device generates electric energy from its surroundings using some kind of energy conversion method. Therefore, the considered energy harvesting device does not consume any fuel or substance. The presented energy harvesting system is used forenergy harvesting of electrical energy from mechanical shocks. The presented energy harvesting system uses a very sensitive vibration energy harvester, which w...

  8. Food and nutritional security requires adequate protein as well as energy, delivered from whole-year crop production.

    Science.gov (United States)

    Coles, Graeme D; Wratten, Stephen D; Porter, John R

    2016-01-01

    Human food security requires the production of sufficient quantities of both high-quality protein and dietary energy. In a series of case-studies from New Zealand, we show that while production of food ingredients from crops on arable land can meet human dietary energy requirements effectively, requirements for high-quality protein are met more efficiently by animal production from such land. We present a model that can be used to assess dietary energy and quality-corrected protein production from various crop and crop/animal production systems, and demonstrate its utility. We extend our analysis with an accompanying economic analysis of commercially-available, pre-prepared or simply-cooked foods that can be produced from our case-study crop and animal products. We calculate the per-person, per-day cost of both quality-corrected protein and dietary energy as provided in the processed foods. We conclude that mixed dairy/cropping systems provide the greatest quantity of high-quality protein per unit price to the consumer, have the highest food energy production and can support the dietary requirements of the highest number of people, when assessed as all-year-round production systems. Global food and nutritional security will largely be an outcome of national or regional agroeconomies addressing their own food needs. We hope that our model will be used for similar analyses of food production systems in other countries, agroecological zones and economies.

  9. Conservation of Mechanical Energy Using Dry Ice Slider-Projectiles

    Science.gov (United States)

    Gales, Jenna; Baker, Blane

    2008-01-01

    Energy concepts are fundamentally important for describing and analyzing systems ranging from subatomic particles to spiral galaxies. In general, students first encounter such concepts in introductory courses that typically focus on forms of energy, energy transfer, and conservation laws. Within these courses, conservation of mechanical energy is…

  10. INCREASE OF ACCURACY ESTIMATION OF BRAKING MECHANISM ENERGY LOADING

    Directory of Open Access Journals (Sweden)

    V. Shein

    2011-01-01

    Full Text Available The components of the energy balance of the braking vehicle that can be used at braking mechanisms energy loading for specified algorithm of qualimetric estimation carrying out are deter-mined.

  11. The United Kingdom`s renewable energy support mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, J.

    1997-06-01

    This report focuses on the UK`s programme of grid-connected non-fossil fuel obligated (NFFO) energy operation, and outlines the objectives of the support mechanisms, and the support mechanism for England, Wales, Scotland and Northern Ireland. The results of the renewable support mechanism are summarised covering capacities and numbers, contract price, successes and failures, incentives and finance mechanisms. (UK)

  12. Energy phase shift as mechanism for catalysis

    KAUST Repository

    Beke-Somfai, Tamás

    2012-05-01

    Catalysts are agents that by binding reactant molecules lower the energy barriers to chemical reaction. After reaction the catalyst is regenerated, its unbinding energy recruited from the environment, which is associated with an inevitable loss of energy. We show that combining several catalytic sites to become energetically and temporally phase-shifted relative to each other provides a possibility to sustain the overall reaction by internal \\'energy recycling\\', bypassing the need for thermal activation, and in principle allowing the system to work adiabatically. Using an analytical model for superimposed, phase-shifted potentials of F 1-ATP synthase provides a description integrating main characteristics of this rotary enzyme complex. © 2012 Elsevier B.V. All rights reserved.

  13. Compensatory mechanisms activated with intermittent energy restriction

    DEFF Research Database (Denmark)

    Coutinho, Sílvia Ribeiro; Halset, Eline Holli; Gåsbakk, Sigrid

    2017-01-01

    : 39 ± 9 y) with obesity (BMI: 36 ± 4 kg/m2) were randomized to lose a similar weight with an IER (N = 18) or a CER (N = 17) diet over a 12 week period. Macronutrient composition and overall energy restriction (33% reduction) were similar between groups. Body weight/composition, RMR, fasting......) were measured before and after WL. Results: Changes in body weight (≈12.5% WL) and composition were similar in both groups. Fasting RQ and ExEff at 10 W increased in both groups. Losing weight, either by IER or CER dieting, did not induce significant changes in subjective appetite ratings. RMR......Background & aims: Strong compensatory responses, with reduced resting metabolic rate (RMR), increased exercise efficiency (ExEff) and appetite, are activated when weight loss (WL) is achieved with continuous energy restriction (CER), which try to restore energy balance. Intermittent energy...

  14. The mechanical energy equation for total flow in open channels

    Institute of Scientific and Technical Information of China (English)

    刘士和; 范敏; 薛娇

    2014-01-01

    The mechanical energy equation is a fundamental equation of a 1-D mathematical model in Hydraulics and Engineering Fluid Mechanics. This equation for the total flow used to be deduced by extending the Bernoulli’s equation for the ideal fluid in the streamline to a stream tube, and then revised by considering the viscous effect and integrated on the cross section. This derivation is not rigorous and the effect of turbulence is not considered. In this paper, the energy equation for the total flow is derived by using the Navier-Stokes equations in Fluid Mechanics, the results are as follows:(1) A new energy equation for steady channel flows of in-compressible homogeneous liquid is obtained, which includes the variation of the turbulent kinetic energy along the channel, the for-mula for the mechanical energy loss of the total flow can be determined directly in the deduction process. (2) The theoretical solution of the velocity field for laminar flows in a rectangular open channel is obtained and the mechanical energy loss in the energy equa-tion is calculated. The variations of the coefficient of the mechanical energy loss against the Reynolds number and the width-depth ratio are obtained. (3) The turbulent flow in a rectangular open channel is simulated using 3-D Reynolds averaged equations closed by the Reynolds stress model (RSM), and the variations of the coefficient of the mechanical energy loss against the Reynolds number and the width-depth ratio are discussed.

  15. A Better 2-D Mechanical Energy Conservation Experiment

    Science.gov (United States)

    Paesler, Michael

    2012-01-01

    A variety of simple classical mechanics energy conservation experiments are used in teaching laboratories. Typical one-dimensional (1-D) setups may involve falling balls or oscillating springs. Many of these can be quite satisfying in that students can confirm--within a few percent--that mechanical energy is conserved. Students generally have…

  16. An Energy Model of a Failure Mechanism and its Application

    Institute of Scientific and Technical Information of China (English)

    MA Xiao-ning; LU Zhen-zhou

    2003-01-01

    The energy expression is presented for a failure mechanism, and it is applied in an Accelerated Life Test (ALT) and an Accelerated Reliability Growth Test (ARGT). The conditions of the common failure mechanism are obtained. The essential relationship between the conditions and the Accelerated Factor (Af) is proposed by using the energy model.

  17. Mechanical engineers' handbook, energy and power

    CERN Document Server

    Kutz, Myer

    2015-01-01

    The engineer's ready reference for mechanical power and heat Mechanical Engineer's Handbook provides the mostcomprehensive coverage of the entire discipline, with a focus onexplanation and analysis. Packaged as a modular approach, thesebooks are designed to be used either individually or as a set,providing engineers with a thorough, detailed, ready reference ontopics that may fall outside their scope of expertise. Each bookprovides discussion and examples as opposed to straight data andcalculations, giving readers the immediate background they needwhile pointing them toward more in-depth infor

  18. Nanoscale mechanical energy harvesting using piezoelectricity and flexoelectricity

    Science.gov (United States)

    Liang, Xu; Hu, Shuling; Shen, Shengping

    2017-03-01

    Due to the electromechanical coupling effect, mechanical energy can be converted into electrical energy in certain materials. A theoretical framework is established to investigate the circuit voltage, electric power of nanoscale mechanical energy harvesting, in which the mechanical vibration energy was converted into electrical energy by piezoelectric and flexoelectric effects. Analytical solutions for the maximum electric potential, circuit voltage and electric power generated in bent BaTiO3 (BT), ZnO nanowires (NWs) and Pb(Mg1/3Nb2/3)O3 (PMN) nanofilms (NFs) were derived. Static and dynamic analyses are conducted to obtain the fundamental information of these mechanical energy harvestings. Different from the previous studies, the flexoelectric-mechanism are included in the fundamental mechanical frameworks. The maximum electric potential generated in the BT, ZnO NWs and PMN NF is found to be enhanced by flexoelectricity in the static case, meanwhile the circuit voltage and electric power are dramatic enhanced by flexoelectricity when the geometric dimensions shrinks to dozens of nanometers. The mechanical limitation condition is employed to calculate the practical maximum electric potential, circuit voltage and electric power. This work tries to provide a comprehensive understanding of the mechanical energy harvesting capability of these nanoscale structures and provide valuable information for designing flexoelectricity-based nanogenerator devices.

  19. Efficiency of a gyroscopic device for conversion of mechanical wave energy to electrical energy

    DEFF Research Database (Denmark)

    Carlsen, Martin; Darula, Radoslav; Gravesen, Jens;

    2011-01-01

    We consider a recently proposed gyroscopic device for conversion of mechanical ocean wave energy to electrical energy. Two models of the device derived from standard engineering mechanics from the literature are analysed, and a model is derived from analytical mechanics considerations. From...

  20. Rotary triboelectric nanogenerator based on a hybridized mechanism for harvesting wind energy.

    Science.gov (United States)

    Xie, Yannan; Wang, Sihong; Lin, Long; Jing, Qingshen; Lin, Zong-Hong; Niu, Simiao; Wu, Zhengyun; Wang, Zhong Lin

    2013-08-27

    Harvesting mechanical energy is becoming increasingly important for its availability and abundance in our living environment. Triboelectric nanogenerator (TENG) is a simple, cost-effective, and highly efficient approach for generating electricity from mechanical energies in a wide range of forms. Here, we developed a TENG designed for harvesting tiny-scale wind energy available in our normal living environment using conventional materials. The energy harvester is based on a rotary driven mechanical deformation of multiple plate-based TENGs. The operation mechanism is a hybridization of the contact-sliding-separation-contact processes by using the triboelectrification and electrostatic induction effects. With the introduction of polymer nanowires on surfaces, the rotary TENG delivers an open-circuit voltage of 250 V and a short-circuit current of 0.25 mA, corresponding to a maximum power density of ~39 W/m(2) at a wind speed of ~15 m/s, which is capable of directly driving hundreds of electronic devices such as commercial light-emitting diodes (LEDs), or rapidly charging capacitors. The rotary TENG was also applied as a self-powered sensor for measuring wind speed. This work represents a significant progress in the practical application of the TENG and its great potential in the future wind power technology. This technology can also be extended for harvesting energy from ocean current, making nanotechnology reaching our daily life a possibility in the near future.

  1. Nanogenerators Convert Mechanical Energy into Electricity

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Nano-devices are at the most active research frontier in today's world thanks to their unmatched features such as miniature dimension, lowenergy consumption, high sensitivity in performance. Researchers have developed a broad range of nanodevices with various applications including in situ, real-time biomedical monitoring and detection,but their use has been limited by the sources of energy available to power them. Conventional batteries make the nanoscale systems too large, and the toxic contents of batteries limit their use in human body.

  2. An estimate of spherical impactor energy transfer for mechanical frequency up-conversion energy harvester

    Science.gov (United States)

    Corr, L. R.; Ma, D. T.

    2016-08-01

    Vibration energy harvesters, which use the impact mechanical frequency up-conversion technique, utilize an impactor, which gains kinetic energy from low frequency ambient environmental vibrations, to excite high frequency systems that efficiently convert mechanical energy to electrical energy. To take full advantage of the impact mechanical frequency up-conversion technique, it is prudent to understand the energy transfer from the low frequency excitations, to the impactor, and finally to the high frequency systems. In this work, the energy transfer from a spherical impactor to a multi degree of freedom spring / mass system, due to Hertzian impact, is investigated to gain insight on how best to design impact mechanical frequency up-conversion energy harvesters. Through this academic work, it is shown that the properties of the contact (or impact) area, i.e., radius of curvature and material properties, only play a minor role in energy transfer and that the equivalent mass of the target system (i.e., the spring / mass system) dictates the total amount of energy transferred during the impact. The novel approach of utilizing the well-known Hertzian impact methodology to gain an understanding of impact mechanical frequency up-conversion energy harvesters has made it clear that the impactor and the high frequency energy generating systems must be designed together as one system to ensure maximum energy transfer, leading to efficient ambient vibration energy harvesters.

  3. Improved Scheduling Mechanisms for Synchronous Information and Energy Transmission.

    Science.gov (United States)

    Qin, Danyang; Yang, Songxiang; Zhang, Yan; Ma, Jingya; Ding, Qun

    2017-06-09

    Wireless energy collecting technology can effectively reduce the network time overhead and prolong the wireless sensor network (WSN) lifetime. However, the traditional energy collecting technology cannot achieve the balance between ergodic channel capacity and average collected energy. In order to solve the problem of the network transmission efficiency and the limited energy of wireless devices, three improved scheduling mechanisms are proposed: improved signal noise ratio (SNR) scheduling mechanism (IS2M), improved N-SNR scheduling mechanism (INS2M) and an improved Equal Throughput scheduling mechanism (IETSM) for different channel conditions to improve the whole network performance. Meanwhile, the average collected energy of single users and the ergodic channel capacity of three scheduling mechanisms can be obtained through the order statistical theory in Rayleig, Ricean, Nakagami-m and Weibull fading channels. It is concluded that the proposed scheduling mechanisms can achieve better balance between energy collection and data transmission, so as to provide a new solution to realize synchronous information and energy transmission for WSNs.

  4. Energy efficiency of error correcting mechanisms for wireless communications

    NARCIS (Netherlands)

    Havinga, Paul J.M.

    We consider the energy efficiency of error control mechanisms for wireless communication. Since high error rates are inevitable to the wireless environment, energy efficient error control is an important issue for mobile computing systems. Although good designed retransmission schemes can be optimal

  5. Conservation of Mechanical and Electric Energy: Simple Experimental Verification

    Science.gov (United States)

    Ponikvar, D.; Planinsic, G.

    2009-01-01

    Two similar experiments on conservation of energy and transformation of mechanical into electrical energy are presented. Both can be used in classes, as they offer numerous possibilities for discussion with students and are simple to perform. Results are presented and are precise within 20% for the version of the experiment where measured values…

  6. Determination of total mechanical energy of the universe within the framework of Newtonian mechanics

    CERN Document Server

    Valev, Dimitar

    2009-01-01

    The recent astronomical observations indicate that the expanding universe having a finite event horizon is homogeneous, isotropic and asymptotically flat. The Euclidean geometry of the universe enables to determine the total kinetic and gravitational energies of the universe within the framework of the Newtonian mechanics. It has been shown that almost the entire kinetic energy of the universe ensues from the cosmological expansion. Both, the total kinetic and gravitational energies of the universe have been determined in relation to an observer at arbitrary location. It is amazing that the modulus of the total gravitational energy differs from the total kinetic energy with a multiplier close to a unit. Thus, the total mechanical energy of the universe has been found close to zero. Both, the total kinetic energy and the modulus of total gravitational energy of the universe are estimated to 3/10 of its total rest energy M*c^2.

  7. Mechanical energy oscillations of two brachiation gaits: measurement and simulation.

    Science.gov (United States)

    Bertram, J E; Chang, Y H

    2001-08-01

    How do arm-swinging apes locomote effectively over a variety of speeds? One way to reduce the metabolic energy cost of locomotion is to transfer energy between reversible mechanical modes. In terrestrial animals, at least two transfer mechanisms have been identified: 1) a pendulum-like mechanism for walking, with exchange between gravitational potential energy and translational kinetic energy, and 2) a spring-like mechanism for running, where the elastic strain energy of stretched muscle and tendon is largely returned to reaccelerate the animal. At slower speeds, a brachiator will always have at least one limb in contact with the support, similar to the overlap of foot contact in bipedal walking. At faster speeds, brachiators exhibit an aerial phase, similar to that seen in bipedal running. Are there two distinct brachiation gaits even though the animal appears to simply swing beneath its overhead support? If so, are different exchange mechanisms employed? Our kinetic analysis of brachiation in a white-handed gibbon (Hylobates lar) indicates that brachiation is indeed comprised of two mechanically distinct gaits. At slower speeds in "continuous contact" brachiation, the gibbon utilizes a simple pendulum-like transfer of mechanical energy within each stride. At faster speeds in "ricochetal" brachiation, translational and rotational kinetic energy are exchanged in a novel "whip-like" transfer. We propose that brachiators utilize the transfer between translational and rotational kinetic energy to control the dynamics of their swing. This maneuver may allow muscle action at the shoulder to control the transfer and adjust the ballistic portion of the step to meet the requirements for the next hand contact.

  8. Losing energy in classical, relativistic and quantum mechanics

    NARCIS (Netherlands)

    Atkinson, David

    2007-01-01

    A Zenonian supertask involving an infinite number of colliding balls is considered, under the restriction that the total mass of all the balls is finite. Classical mechanics leads to the conclusion that momentum, but not necessarily energy, must be conserved. In relativistic mechanics, however, neit

  9. Energy conversion via ferroic materials: Materials, mechanisms, and applications

    Science.gov (United States)

    Chin, Huai-An

    Energy conversion is a process converting one form of energy into another. Significant research effort has been dedicated to energy conversion mechanisms for portable energy conversion. Specifically, mechanisms based on ferroic materials have been widely explored for this goal. Ferroic materials include ferromagnetic, ferroelectric and ferroelastic materials. This thesis is focused on two ferroic materials: ferromagnetic TbxDy1-xFe2 (x ˜ 0.3, Terfenol-D), and ferroelectric barium strontium titanate (BST) including its paraelectric phase, for their energy conversion mechanisms. We grew and characterized these materials, followed by device fabrication to study potential energy conversion mechanisms in resulting devices. With Terfenol-D, we demonstrated a wireless energy-conversion process via the Villari effect, i.e. magnetic flux change induced by mechanical input. A new technique of transfer-printing a Terfenol-D film onto a flexible substrate was developed to study this mechanism. The transferred Terfenol-D showed a high saturation magnetization (˜ 1.3 T) and flexibility (strain ˜ 1.9 %). Subsequently, the Villari effect was successfully utilized to convert mechanical energy, from a mechanical source and a simulated biomechanical source, into electricity. For next projects, another ferroic material, a high-permittivity (dielectric constant ˜ 200) BST was sputtered on Pt/SiO2/Si or stainless steels to form a metal-insulator(BST)-metal heterostructure. The BST was found to be paraelectric when grown upon Pt/SiO2/Si, whereas it was ferroelectric when grown on the stainless steel. Two different mechanisms were therefore studied on these two modifications. In the paraelectric BST we found a new thermal-electric response via a flexoelectricity-mediated mechanism, which was enabled by a large strain gradient (> 104/m) produced by lattice mismatch. With the enhanced flexoelectricity from the large strain gradient, electrical output was generated under thermal cycling

  10. Flexible hybrid energy cell for simultaneously harvesting thermal, mechanical, and solar energies.

    Science.gov (United States)

    Yang, Ya; Zhang, Hulin; Zhu, Guang; Lee, Sangmin; Lin, Zong-Hong; Wang, Zhong Lin

    2013-01-22

    We report the first flexible hybrid energy cell that is capable of simultaneously or individually harvesting thermal, mechanical, and solar energies to power some electronic devices. For having both the pyroelectric and piezoelectric properties, a polarized poly(vinylidene fluoride) (PVDF) film-based nanogenerator (NG) was used to harvest thermal and mechanical energies. Using aligned ZnO nanowire arrays grown on the flexible polyester (PET) substrate, a ZnO-poly(3-hexylthiophene) (P3HT) heterojunction solar cell was designed for harvesting solar energy. By integrating the NGs and the solar cells, a hybrid energy cell was fabricated to simultaneously harvest three different types of energies. With the use of a Li-ion battery as the energy storage, the harvested energy can drive four red light-emitting diodes (LEDs).

  11. Electric power emergency management mechanism considering the access of new energy and renewable energy

    Science.gov (United States)

    Zhang, Baoqun; Ma, Longfei; Gong, Cheng; Jiao, Ran; Shi, Rui; Chi, Zhongjun; Ding, Yifeng

    2017-01-01

    Scholars at home and abroad have had a thorough research about the theory system and the frame of emergency management on the background of traditional grid, but for the improvement of the emergency mechanism when new energy and renewable energy access the grid, more work should be done. This paper will summarize the predecessors' work on emergency management, discuss the impact of emergency management while new energy and renewable energy access the grid and some suggestions are given.

  12. Mechanisms linking energy balance and reproduction: impact of prenatal environment.

    Science.gov (United States)

    Rhinehart, Erin M

    2016-01-01

    The burgeoning field of metabolic reproduction regulation has been gaining momentum due to highly frequent discoveries of new neuroendocrine factors regulating both energy balance and reproduction. Universally throughout the animal kingdom, energy deficits inhibit the reproductive axis, which demonstrates that reproduction is acutely sensitive to fuel availability. Entrainment of reproductive efforts with energy availability is especially critical for females because they expend large amounts of energy on gestation and lactation. Research has identified an assortment of both central and peripheral factors involved in the metabolic regulation of reproduction. From an evolutionary perspective, these mechanisms likely evolved to optimize reproductive fitness in an environment with an unpredictable food supply and regular bouts of famine. To be effective, however, the mechanisms responsible for the metabolic regulation of reproduction must also retain developmental plasticity to allow organisms to adapt their reproductive strategies to their particular niche. In particular, the prenatal environment has emerged as a critical developmental window for programming the mechanisms responsible for the metabolic control of reproduction. This review will discuss the current knowledge about hormonal and molecular mechanisms that entrain reproduction with prevailing energy availability. In addition, it will provide an evolutionary, human life-history framework to assist in the interpretation of findings on gestational programming of the female reproductive function, with a focus on pubertal timing as an example. Future research should aim to shed light on mechanisms underlying the prenatal modulation of the adaptation to an environment with unstable resources in a way that optimizes reproductive fitness.

  13. A new mechanism for energy conservation technology services

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Feng

    1996-12-31

    In the ninth-five year plan of China, the socialist market economy model will be developed. In the stage of transferring from planning economy to market economy, the energy conservation technology services industry in China has met new challenges. Over the past ten to fifteen years, there has developed a new mechanism for financing energy efficiency investments in market economies. The process is simple. After inspecting an enterprise or an entity for energy saving opportunities, an Energy Service Company (ESCO) which business aimed at making money will review the recommended energy conservation opportunities with the enterprise or the entity (user) and implement those measures acceptable to the user at no front end cost to the user. The ESCO then guarantees that the energy savings will cover the cost of the capital renovations using the Performance Contracting.

  14. Comparison of film measurements and Monte Carlo simulations of dose delivered with very high-energy electron beams in a polystyrene phantom

    Energy Technology Data Exchange (ETDEWEB)

    Bazalova-Carter, Magdalena; Liu, Michael; Palma, Bianey; Koong, Albert C.; Maxim, Peter G., E-mail: Peter.Maxim@Stanford.edu, E-mail: BWLoo@Stanford.edu; Loo, Billy W., E-mail: Peter.Maxim@Stanford.edu, E-mail: BWLoo@Stanford.edu [Department of Radiation Oncology, Stanford University, Stanford, California 94305-5847 (United States); Dunning, Michael; McCormick, Doug; Hemsing, Erik; Nelson, Janice; Jobe, Keith; Colby, Eric; Tantawi, Sami; Dolgashev, Valery [SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2015-04-15

    Purpose: To measure radiation dose in a water-equivalent medium from very high-energy electron (VHEE) beams and make comparisons to Monte Carlo (MC) simulation results. Methods: Dose in a polystyrene phantom delivered by an experimental VHEE beam line was measured with Gafchromic films for three 50 MeV and two 70 MeV Gaussian beams of 4.0–6.9 mm FWHM and compared to corresponding MC-simulated dose distributions. MC dose in the polystyrene phantom was calculated with the EGSnrc/BEAMnrc and DOSXYZnrc codes based on the experimental setup. Additionally, the effect of 2% beam energy measurement uncertainty and possible non-zero beam angular spread on MC dose distributions was evaluated. Results: MC simulated percentage depth dose (PDD) curves agreed with measurements within 4% for all beam sizes at both 50 and 70 MeV VHEE beams. Central axis PDD at 8 cm depth ranged from 14% to 19% for the 5.4–6.9 mm 50 MeV beams and it ranged from 14% to 18% for the 4.0–4.5 mm 70 MeV beams. MC simulated relative beam profiles of regularly shaped Gaussian beams evaluated at depths of 0.64 to 7.46 cm agreed with measurements to within 5%. A 2% beam energy uncertainty and 0.286° beam angular spread corresponded to a maximum 3.0% and 3.8% difference in depth dose curves of the 50 and 70 MeV electron beams, respectively. Absolute dose differences between MC simulations and film measurements of regularly shaped Gaussian beams were between 10% and 42%. Conclusions: The authors demonstrate that relative dose distributions for VHEE beams of 50–70 MeV can be measured with Gafchromic films and modeled with Monte Carlo simulations to an accuracy of 5%. The reported absolute dose differences likely caused by imperfect beam steering and subsequent charge loss revealed the importance of accurate VHEE beam control and diagnostics.

  15. Energy Monitoring and Management Mechanism for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Papadakis Andreas

    2016-01-01

    Full Text Available In this work we discuss a mechanism for the monitoring and management of energy consumption in Wireless Sensor Networks. We consider that the Wireless Sensor Network consists of nodes that operate individually and collaborate with each other. After briefly discussing the typical network topologies and associating with the expected communications needs, we describe a conceptual framework for monitoring and managing the energy consumption on per process basis.

  16. Thermo-mechanical modelling of high energy particle beam impacts

    CERN Document Server

    Scapin, M; Dallocchio, A

    2010-01-01

    The unprecedented energy intensities of modern hadron accelerators yield special problems with the materials that are placed close to or into the high intensity beams. The energy stored in LHC in a single beam is equivalent to about 80 kg of TNT explosive, stored in a transverse beam area of 0.2 mm×0.2 mm. The materials placed close to the beam are used at, or even beyond, their damage limits. However, it is very difficult to predict structural efficiency and robustness accurately: beam-induced damage occurs in a regime where practical experience does not exist. This study is performed in order to estimate the damage on a copper component due to the impact with a 7 TeV proton beam generated by LHC. The case study represents an accidental case consequent to an abnormal release of the beam, in which 8 bunches irradiate the target directly. The energy delivered on the component is calculated using the FLUKA code and then used as input in the numerical simulations, that are carried out via the FEM code LS-DYNA. ...

  17. Bottlenecks to vibrational energy flow in OCS: Structures and mechanisms

    CERN Document Server

    Paškauskas, R; Uzer, T

    2008-01-01

    Finding the causes for the nonstatistical vibrational energy relaxation in the planar carbonyl sulfide (OCS) molecule is a longstanding problem in chemical physics: Not only is the relaxation incomplete long past the predicted statistical relaxation time, but it also consists of a sequence of abrupt transitions between long-lived regions of localized energy modes. We report on the phase space bottlenecks responsible for this slow and uneven vibrational energy flow in this Hamiltonian system with three degrees of freedom. They belong to a particular class of two-dimensional invariant tori which are organized around elliptic periodic orbits. We relate the trapping and transition mechanisms with the linear stability of these structures.

  18. Toward Low-Frequency Mechanical Energy Harvesting Using Energy-Dense Piezoelectrochemical Materials.

    Science.gov (United States)

    Cannarella, John; Arnold, Craig B

    2015-12-02

    The piezoelectrochemical coupling between mechanical stress and electrochemical potential is explored in the context of mechanical energy harvesting and shown to have promise in developing high-energy-density harvesters for low-frequency applications (e.g., human locomotion). This novel concept is demonstrated experimentally by cyclically compressing an off-the-shelf lithium-ion battery and measuring the generated electric power output.

  19. Human Energy Expenditure and Postural Coordination on the Mechanical Horse.

    Science.gov (United States)

    Baillet, Héloïse; Thouvarecq, Régis; Vérin, Eric; Tourny, Claire; Benguigui, Nicolas; Komar, John; Leroy, David

    2017-01-01

    The authors investigated and compared the energy expenditure and postural coordination of two groups of healthy subjects on a mechanical horse at 4 increasing oscillation frequencies. Energy expenditure was assessed from the oxygen consumption, respiratory quotient, and heart rate values, and postural coordination was characterized by relative phase computations between subjects (elbow, head, trunk) and horse. The results showed that the postural coordination of the riders was better adapted (i.e., maintenance of in-phase and antiphase) than that of the nonriders, but the energy expenditure remains the same. Likewise, we observed an energy system shifting only for nonriders (from aerobic to lactic anaerobic mode). Finally, cross-correlations showed a link between energy expenditure and postural coordination in the riders (i.e., effectiveness).

  20. Conversion of the zero-point energy of the quantum vacuum into classical mechanical energy

    Energy Technology Data Exchange (ETDEWEB)

    Turtur, Claus Wilhelm

    2010-07-01

    A perpetual motion machine - this can never exist. But energy sources nearly disregarded up to now - they exist. These are energy sources, which have been hardly under investigation, so that mankind did not yet learn how to get benefit from them. Most part of the universe consists of such energy, which is still called 'invisible'. A part of this energy is to be found within the so called zero-point oscillations of the quantum vacuum, thus within the empty void from the perspective of quantum physics. The author of the book is physicist. He theoretically developed and then experimentally verified a method for the conversion of vacuum energy into classical mechanical energy. His technique is one of the very few approaches known up to know. The most prominent approaches to convert vacuum energy are described in this book in many scientific details, and they are compared with other known proposals for the use of vacuum energy. (orig.)

  1. Quantitative Financial Analysis of Alternative Energy Efficiency Shareholder Incentive Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Cappers, Peter; Goldman, Charles; Chait, Michele; Edgar, George; Schlegel, Jeff; Shirley, Wayne

    2008-08-03

    Rising energy prices and climate change are central issues in the debate about our nation's energy policy. Many are demanding increased energy efficiency as a way to help reduce greenhouse gas emissions and lower the total cost of electricity and energy services for consumers and businesses. Yet, as the National Action Plan on Energy Efficiency (NAPEE) pointed out, many utilities continue to shy away from seriously expanding their energy efficiency program offerings because they claim there is insufficient profit-motivation, or even a financial disincentive, when compared to supply-side investments. With the recent introduction of Duke Energy's Save-a-Watt incentive mechanism and ongoing discussions about decoupling, regulators and policymakers are now faced with an expanded and diverse landscape of financial incentive mechanisms, Determining the 'right' way forward to promote deep and sustainable demand side resource programs is challenging. Due to the renaissance that energy efficiency is currently experiencing, many want to better understand the tradeoffs in stakeholder benefits between these alternative incentive structures before aggressively embarking on a path for which course corrections can be time-consuming and costly. Using a prototypical Southwest utility and a publicly available financial model, we show how various stakeholders (e.g. shareholders, ratepayers, etc.) are affected by these different types of shareholder incentive mechanisms under varying assumptions about program portfolios. This quantitative analysis compares the financial consequences associated with a wide range of alternative incentive structures. The results will help regulators and policymakers better understand the financial implications of DSR program incentive regulation.

  2. Identification of energy dissipation mechanisms in CNT-reinforced nanocomposites

    Science.gov (United States)

    Gardea, Frank; Glaz, Bryan; Riddick, Jaret; Lagoudas, Dimitris C.; Naraghi, Mohammad

    2016-03-01

    In this paper we present our recent findings on the mechanisms of energy dissipation in polymer-based nanocomposites obtained through experimental investigations. The matrix of the nanocomposite was polystyrene (PS) which was reinforced with carbon nanotubes (CNTs). To study the mechanical strain energy dissipation of nanocomposites, we measured the ratio of loss to storage modulus for different CNT concentrations and alignments. CNT alignment was achieved via hot-drawing of PS-CNT. In addition, CNT agglomeration was studied via a combination of SEM imaging and Raman scanning. We found that at sufficiently low strains, energy dissipation in composites with high CNT alignment is not a function of applied strain, as no interfacial slip occurs between the CNTs and PS. However, below the interfacial slip strain threshold, damping scales monotonically with CNT content, which indicates the prevalence of CNT-CNT friction dissipation mechanisms within agglomerates. At higher strains, interfacial slip also contributes to energy dissipation. However, the increase in damping with strain, especially when CNT agglomerates are present, does not scale linearly with the effective interface area between CNTs and PS, suggesting a significant contribution of friction between CNTs within agglomerates to energy dissipation at large strains. In addition, for the first time, a comparison between the energy dissipation in randomly oriented and aligned CNT composites was made. It is inferred that matrix plasticity and tearing caused by misorientation of CNTs with the loading direction is a major cause of energy dissipation. The results of our research can be used to design composites with high energy dissipation capability, especially for applications where dynamic loading may compromise structural stability and functionality, such as rotary wing structures and antennas.

  3. The mechanism of mechanical energy accumulation in a nonwetting liquid-nanoporous solid system

    NARCIS (Netherlands)

    Borman, VD; Belogorlov, AA; Grekhov, AM; Lisichkin, GV; Tronin, VN; Troyan, [No Value

    2004-01-01

    The mechanism of mechanical energy accumulation in a nanoporous solid-nonwetting liquid system has been experimentally studied by filling a silica gel based nanoporous sorbent (Libersorb 2U-8) with an aqueous ethylene glycol solution. Interpretation of the experimental data within the framework of t

  4. Hierarchical energy management mechanisms for an electricity market with microgrids

    Directory of Open Access Journals (Sweden)

    Hong-Tzer Yang

    2014-08-01

    Full Text Available This study addresses a micro-grid electricity market (MGEM with day-ahead (DA and real-time market mechanisms integrated. The bidding mechanisms for the market are described in this study, considering the generation cost of different distributed energy resources (DERs, like distributed generator, energy storage system and demand response. Including load and renewable generation forecasting systems and a fuzzy decision supporting system, a hierarchical micro-grid energy management system (MG-EMS is then proposed to ensure the benefits of involved micro-grid central controller, DER owners and customers. To verify the feasibility of the proposed system, the whole-year historical pricing and load data for New England independent system operator are employed. The numerical results show that the proposed MG-EMS is promising and effective for the operations of MGEM.

  5. Rotating-Sleeve Triboelectric-Electromagnetic Hybrid Nanogenerator for High Efficiency of Harvesting Mechanical Energy.

    Science.gov (United States)

    Cao, Ran; Zhou, Tao; Wang, Bin; Yin, Yingying; Yuan, Zuqing; Li, Congju; Wang, Zhong Lin

    2017-08-22

    Currently, a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG) have been hybridized to effectively scavenge mechanical energy. However, one critical issue of the hybrid device is the limited output power due to the mismatched output impedance between the two generators. In this work, impedance matching between the TENG and EMG is achieved facilely through commercial transformers, and we put forward a highly integrated hybrid device. The rotating-sleeve triboelectric-electromagnetic hybrid nanogenerator (RSHG) is designed by simulating the structure of a common EMG, which ensures a high efficiency in transferring ambient mechanical energy into electric power. The RSHG presents an excellent performance with a short-circuit current of 1 mA and open-circuit voltage of 48 V at a rotation speed of 250 rpm. Systematic measurements demonstrate that the hybrid nanogenerator can deliver the largest output power of 13 mW at a loading resistance of 8 kΩ. Moreover, it is demonstrated that a wind-driven RSHG can light dozens of light-emitting diodes and power an electric watch. The distinctive structure and high output performance promise the practical application of this rotating-sleeve structured hybrid nanogenerator for large-scale energy conversion.

  6. Real single ion solvation free energies with quantum mechanical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, Timothy TS; Baer, Marcel D.; Schenter, Gregory K.; Mundy, Christopher J.

    2017-09-01

    Single ion solvation free energies are one of the most important properties of electrolyte solution and yet there is ongoing debate about what these values are. Experimental methods can only determine the values for neutral ion pairs. Here, we use DFT interaction potentials with molecular dynamics simulation (DFT-MD) combined with a modified version of the quasi chemical theory (QCT) to calculate these energies for the lithium and fluoride ions. A new method to rigorously correct for the error in the DFT functional is developed and very good agreement with the experimental value for the lithium fluoride pair is obtained. Moreover, this method partitions the energies into physically intuitive terms such as surface potential, cavity and charging energies which are amenable to descriptions with reduced models. Our research suggests that lithium’s solvation energy is dominated by the free energetics of a charged hard sphere, whereas fluoride exhibits significant quantum mechanical behavior that cannot be simply described with a reduced model. We would like to thank Thomas Beck, Shawn Kathmann and Sotiris Xantheas for helpful discussions. Computing resources were generously allocated by PNNLs Institutional Computing program. This research also used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. TTD, GKS and CJM were supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. MDB was supported by MS3 (Materials Synthesis and Simulation Across Scales) Initiative, a Laboratory Directed Research and Development Program at Pacific Northwest National Laboratory (PNNL). PNNL is a multi-program national laboratory operated by Battelle for the U.S. Department of Energy.

  7. Prototype device for converting freezing energy into mechanical work

    Energy Technology Data Exchange (ETDEWEB)

    Habeebullah, B.; Zaki, G.M.; Akyurt, M. [Fakieh Center for Applied Research, Makkah Al-Mukarramah (Saudi Arabia)

    2003-01-01

    Certain properties of ice are reviewed. The phenomenon of freezing of water is discussed, with special emphasis on the blockage and bursting of water pipes. Several concepts are discussed that are related to achieving the freezing of water, the design of the container where freezing occurs and the conversion into mechanical energy. A conceptual design is presented for one type of ice energy converter. Certain design details for this machine are provided. Initial test results are furnished for this device, which was manufactured and tested. Conclusions are drawn and recommendations are made. (author)

  8. Energy implications of mechanical and mechanical–biological treatment compared to direct waste-to-energy

    DEFF Research Database (Denmark)

    Cimpan, Ciprian; Wenzel, Henrik

    2013-01-01

    Primary energy savings potential is used to compare five residual municipal solid waste treatment systems, including configurations with mechanical (MT) and mechanical–biological (MBT) pre-treatment, which produce waste-derived fuels (RDF and SRF), biogas and/or recover additional materials...... for recycling, alongside a system based on conventional mass burn waste-to-energy and ash treatment. To examine the magnitude of potential savings we consider two energy efficiency levels (state-of-the-art and best available technology), the inclusion/exclusion of heat recovery (CHP vs. PP) and three different...... background end-use energy production systems (coal condensing electricity and natural gas heat, Nordic electricity mix and natural gas heat, and coal CHP energy quality allocation). The systems achieved net primary energy savings in a range between 34 and 140 MJprimary/100 MJinput waste, in the different...

  9. Power and energy ratios in mechanical CVT drive control

    Science.gov (United States)

    Balakin, P. D.; Stripling, L. O.

    2017-06-01

    Being based on the principle of providing the systems with adaptation property to the real parameters and operational condition, the mechanical system capable to control automatically the components of convertible power is offered and this allows providing stationary operation of the vehicle engine in the terms of variable external loading. This is achieved by drive control integrated in the power transmission, which implements an additional degree of freedom and operates on the basis of the laws of motion, with the energy of the main power flow by changing automatically the kinematic characteristics of the power transmission, this system being named CVT. The power and energy ratios found allow performing the necessary design calculations of the sections and the links of the mechanical CVT scheme.

  10. Mechanical Energy Recovery during Walking in Patients with Parkinson Disease

    Science.gov (United States)

    Dipaola, Mariangela; Pavan, Esteban E.; Cattaneo, Andrea; Frazzitta, Giuseppe; Pezzoli, Gianni; Cavallari, Paolo; Frigo, Carlo A.

    2016-01-01

    The mechanisms of mechanical energy recovery during gait have been thoroughly investigated in healthy subjects, but never described in patients with Parkinson disease (PD). The aim of this study was to investigate whether such mechanisms are preserved in PD patients despite an altered pattern of locomotion. We consecutively enrolled 23 PD patients (mean age 64±9 years) with bilateral symptoms (H&Y ≥II) if able to walk unassisted in medication-off condition (overnight suspension of all dopaminergic drugs). Ten healthy subjects (mean age 62±3 years) walked both at their ‘preferred’ and ‘slow’ speeds, to match the whole range of PD velocities. Kinematic data were recorded by means of an optoelectronic motion analyzer. For each stride we computed spatio-temporal parameters, time-course and range of motion (ROM) of hip, knee and ankle joint angles. We also measured kinetic (Wk), potential (Wp), total (WtotCM) energy variations and the energy recovery index (ER). Along with PD progression, we found a significant correlation of WtotCM and Wp with knee ROM and in particular with knee extension in terminal stance phase. Wk and ER were instead mainly related to gait velocity. In PD subjects, the reduction of knee ROM significantly diminished both Wp and WtotCM. Rehabilitation treatments should possibly integrate passive and active mobilization of knee to prevent a reduction of gait-related energetic components. PMID:27258183

  11. Piezoelectric compliant mechanism energy harvesters under large base excitations

    Science.gov (United States)

    Ma, Xiaokun; Trolier-McKinstry, Susan; Rahn, Christopher D.

    2016-09-01

    A piezoelectric compliant mechanism (PCM) energy harvester is designed, modeled, and analyzed that consists of a polyvinylidene diflouoride, PVDF unimorph clamped at its base and attached to a compliant mechanism at its tip. The compliant hinge stiffness is carefully tuned to approach a low frequency first mode with an efficient (nearly quadratic) shape that provides a uniform strain distribution. A nonlinear model of the PCM energy harvester under large base excitation is derived to determine the maximum power that can be generated by the device. Experiments with a fabricated PCM energy harvester prototype show that the compliant mechanism introduces a stiffening effect and a much wider bandwidth than a benchmark proof mass cantilever design. The PCM bridge structure self-limits the displacement and maximum strain at large excitations compared with the proof mass cantilever, improving the device robustness. The PCM outperforms the cantilever in both average power and power-strain sensitivity at high accelerations due to the PCM axial stretching effect and its more uniform strain distribution.

  12. Mechanical Energy Recovery during Walking in Patients with Parkinson Disease.

    Directory of Open Access Journals (Sweden)

    Mariangela Dipaola

    Full Text Available The mechanisms of mechanical energy recovery during gait have been thoroughly investigated in healthy subjects, but never described in patients with Parkinson disease (PD. The aim of this study was to investigate whether such mechanisms are preserved in PD patients despite an altered pattern of locomotion. We consecutively enrolled 23 PD patients (mean age 64±9 years with bilateral symptoms (H&Y ≥II if able to walk unassisted in medication-off condition (overnight suspension of all dopaminergic drugs. Ten healthy subjects (mean age 62±3 years walked both at their 'preferred' and 'slow' speeds, to match the whole range of PD velocities. Kinematic data were recorded by means of an optoelectronic motion analyzer. For each stride we computed spatio-temporal parameters, time-course and range of motion (ROM of hip, knee and ankle joint angles. We also measured kinetic (Wk, potential (Wp, total (WtotCM energy variations and the energy recovery index (ER. Along with PD progression, we found a significant correlation of WtotCM and Wp with knee ROM and in particular with knee extension in terminal stance phase. Wk and ER were instead mainly related to gait velocity. In PD subjects, the reduction of knee ROM significantly diminished both Wp and WtotCM. Rehabilitation treatments should possibly integrate passive and active mobilization of knee to prevent a reduction of gait-related energetic components.

  13. Transfer and temporary storage of mechanical energy through rotary movement; Uebertragung und voruebergehende Speicherung mechanischer Energie mithilfe der Drehbewegung

    Energy Technology Data Exchange (ETDEWEB)

    Hamerak, Kurt

    2012-07-01

    One of the most important form of mechanical energy is the rotational energy. By means of this rotational energy, mechanical energy is transferred from the actuating driving motor to the driven machine. Under this aspect, the author of the contribution under consideration reports on the transfer of mechanical energy by means of rotary motion. The author describes the circular movement, rotational energy of a rigid body, angular momentum, performance and angular momentum of an asynchronous motor, transfer of rotational energy through a shaft, gear as a transformer for the rotational energy, Coriolis effect.

  14. PDB ligand conformational energies calculated quantum-mechanically.

    Science.gov (United States)

    Sitzmann, Markus; Weidlich, Iwona E; Filippov, Igor V; Liao, Chenzhong; Peach, Megan L; Ihlenfeldt, Wolf-Dietrich; Karki, Rajeshri G; Borodina, Yulia V; Cachau, Raul E; Nicklaus, Marc C

    2012-03-26

    (RSCC). We repeated these calculations with the solvent model IEFPCM, which yielded energy differences that were generally somewhat lower than the corresponding vacuum results but did not produce a qualitatively different picture. Torsional sampling around the crystal conformation at the molecular mechanics level using the MMFF94s force field typically led to an increase in energy. © 2012 American Chemical Society

  15. Mechanism and activation energy of magnetic skyrmion annihilation obtained from minimum energy path calculations

    Science.gov (United States)

    Lobanov, Igor S.; Jónsson, Hannes; Uzdin, Valery M.

    2016-11-01

    The mechanism and activation energy for the annihilation of a magnetic skyrmion is studied by finding the minimum energy path for the transition in a system described by a Heisenberg-type Hamiltonian extended to include dipole-dipole, Dzyaloshinskii-Moriya, and anisotropy interactions so as to represent a Co monolayer on a Pt(111) surface. The annihilation mechanism involves isotropic shrinking of the skyrmion and slow increase of the energy until the transition state is reached after which the energy drops abruptly as the ferromagnetic final state forms. The maximum energy along the minimum energy path, which gives an estimate of the activation energy within the harmonic approximation of transition state theory, is found to be in excellent agreement with direct Langevin dynamics simulations at relatively high temperature carried out by Rohart et al. [Phys. Rev. B 93, 214412 (2016), 10.1103/PhysRevB.93.214412]. The dipole-dipole interaction, the computationally most demanding term in the Hamiltonian, is found to be important but its effect on the stability of the skyrmion and shape of the transition path can be mimicked accurately by reducing the anisotropy constant in the Hamiltonian.

  16. A nonlinear piezoelectric energy harvester for various mechanical motions

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Kangqi, E-mail: kangqifan@gmail.com [School of Mechano-Electronic Engineering, Xidian University, Xi' an 710071 (China); Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G 2V4 (Canada); Chang, Jianwei; Liu, Zhaohui; Zhu, Yingmin [School of Mechano-Electronic Engineering, Xidian University, Xi' an 710071 (China); Pedrycz, Witold [Department of Electrical and Computer Engineering, University of Alberta, Edmonton T6G 2V4 (Canada)

    2015-06-01

    This study presents a nonlinear piezoelectric energy harvester with intent to scavenge energy from diverse mechanical motions. The harvester consists of four piezoelectric cantilever beams, a cylindrical track, and a ferromagnetic ball, with magnets integrated to introduce the magnetic coupling between the ball and the beams. The experimental results demonstrate that the harvester is able to collect energy from various directions of vibrations. For the vibrations perpendicular to the ground, the maximum peak voltage is increased by 3.2 V and the bandwidth of the voltage above 4 V is increased by more than 4 Hz compared to the results obtained when using a conventional design. For the vibrations along the horizontal direction, the frequency up-conversion is realized through the magnetic coupling. Moreover, the proposed design can harvest energy from the sway motion around different directions on the horizontal plane. Harvesting energy from the rotation motion is also achieved with an operating bandwidth of approximately 6 Hz.

  17. Energy implications of mechanical and mechanical–biological treatment compared to direct waste-to-energy

    Energy Technology Data Exchange (ETDEWEB)

    Cimpan, Ciprian, E-mail: cic@kbm.sdu.dk; Wenzel, Henrik

    2013-07-15

    Highlights: • Compared systems achieve primary energy savings between 34 and 140 MJ{sub primary}/100 MJ{sub input} {sub waste.} • Savings magnitude is foremost determined by chosen primary energy and materials production. • Energy consumption and process losses can be upset by increased technology efficiency. • Material recovery accounts for significant shares of primary energy savings. • Direct waste-to-energy is highly efficient if cogeneration (CHP) is possible. - Abstract: Primary energy savings potential is used to compare five residual municipal solid waste treatment systems, including configurations with mechanical (MT) and mechanical–biological (MBT) pre-treatment, which produce waste-derived fuels (RDF and SRF), biogas and/or recover additional materials for recycling, alongside a system based on conventional mass burn waste-to-energy and ash treatment. To examine the magnitude of potential savings we consider two energy efficiency levels (state-of-the-art and best available technology), the inclusion/exclusion of heat recovery (CHP vs. PP) and three different background end-use energy production systems (coal condensing electricity and natural gas heat, Nordic electricity mix and natural gas heat, and coal CHP energy quality allocation). The systems achieved net primary energy savings in a range between 34 and 140 MJ{sub primary}/100 MJ{sub input} {sub waste}, in the different scenario settings. The energy footprint of transportation needs, pre-treatment and reprocessing of recyclable materials was 3–9.5%, 1–18% and 1–8% respectively, relative to total energy savings. Mass combustion WtE achieved the highest savings in scenarios with CHP production, nonetheless, MBT-based systems had similarly high performance if SRF streams were co-combusted with coal. When RDF and SRF was only used in dedicated WtE plants, MBT-based systems totalled lower savings due to inherent system losses and additional energy costs. In scenarios without heat

  18. Modeling the Q-cycle mechanism of transmembrane energy conversion

    CERN Document Server

    Smirnov, Anatoly Yu

    2011-01-01

    The Q-cycle mechanism plays an important role in the conversion of the redox energy into the energy of the proton electrochemical gradient across the biomembrane. The bifurcated electron transfer reaction, which is built into this mechanism, recycles one electron, thus, allowing to translocate two protons per one electron moving to the high-potential redox chain. We study a kinetic model of the Q-cycle mechanism in an artificial system which mimics the bf complex of plants and cyanobacteria in the regime of ferredoxin-dependent cyclic electron flow. Using methods of condensed matter physics, we derive a set of master equations and describe a time sequence of electron and proton transfer reactions in the complex. We find energetic conditions when the bifurcation of the electron pathways at the positive side of the membrane occurs naturally, without any additional gates. For reasonable parameter values, we show that this system is able to translocate more than 1.8 protons, on average, per one electron, with a t...

  19. Cardiac mechanical energy and effects on the arterial tree.

    Science.gov (United States)

    Muñoz, H R; Sacco, C M

    1997-05-01

    Blood flow pulsatility is the result of the heart's activity as a pump unable to develop steady flow, and its interaction with the arterial tree. Thus, the heart is a cyclic energy generator whose adequate function requires the two phases of this cycle to be normal. Diastolic properties determine the degree of filling of the ventricles and the strength of the following systole. Systole, in turn, must generate enough energy to overcome forces opposing ejection. These can be divided into internal (the mechanical characteristics of the ventricle itself) and external loads (the characteristics of the arterial tree). As a result, hydraulic energy is imparted to blood (external ventricular work) that manifests itself as blood pressure and flow. Given the cyclic nature of cardiac activity, the external ventricular work has steady and pulsatile components. The steady component is energy lost during steady flow because of vascular resistance, and the pulsatile work is that lost in arterial pulsations and mainly depends on the aortic impedance. Thus, the characteristics of the arterial tree will determine the relative contribution of these two components to blood flow and the efficency of the heart. In addition, the arterial tree modifies the different waves (pressure and flow) traveling in the circulation. These modifications have important consequences for cardiac function. The ventricle and the arterial tree constitute a coupled biological system, and its overall performance is a function of the behavior of each unit at any given moment.

  20. Renewable energy: An efficient mechanism to improve GDP

    Energy Technology Data Exchange (ETDEWEB)

    Chien Taichen [Chung-Hua Institute for Economic Research, Taipei, Taiwan (China)], E-mail: tcchien@hotmail.com; Hu Jinli [Institute of Business and Management, National Chiao Tung University, Taiwan (China)

    2008-08-15

    This article analyzes the effects of renewable energy on GDP for 116 economies in 2003 through Structural Equation Modeling (SEM) approach. In order to decipher the mechanism of how the use of renewables improves macroeconomic efficiency, we decompose GDP by the 'expenditure approach'. Although previous theory predicts positive effects of renewables on capital formation and trade balance, the SEM results show that renewables have a significant positive influence on capital formation only. The result that renewables do not have a significant impact on trade balance implies that renewables do not have an import substitution effect. Thus, we confirm the positive relationship between renewable energy and GDP through the path of increasing capital formation, but not for the path of increasing trade balance.

  1. Renewable energy: An efficient mechanism to improve GDP

    Energy Technology Data Exchange (ETDEWEB)

    Chien, Taichen [Chung-Hua Institute for Economic Research, Taipei (China); Hu, Jin-Li [Institute of Business and Management, National Chiao Tung University (China)

    2008-08-15

    This article analyzes the effects of renewable energy on GDP for 116 economies in 2003 through Structural Equation Modeling (SEM) approach. In order to decipher the mechanism of how the use of renewables improves macroeconomic efficiency, we decompose GDP by the ''expenditure approach''. Although previous theory predicts positive effects of renewables on capital formation and trade balance, the SEM results show that renewables have a significant positive influence on capital formation only. The result that renewables do not have a significant impact on trade balance implies that renewables do not have an import substitution effect. Thus, we confirm the positive relationship between renewable energy and GDP through the path of increasing capital formation, but not for the path of increasing trade balance. (author)

  2. Trainsient Accretion Disk and Energy Mechanism of Gamma Ray Bursts

    Institute of Scientific and Technical Information of China (English)

    LU Ye; ZHENG Guang-Sheng; ZHAO Gang; YANG Lan-Tian

    2000-01-01

    We suggest that a rotating massive black hole (106M ) located at an inactive galaxy may convert its host into a transient active phase by capturing and disrupting a star. During this period, a transient accretion disk is formed and a strong transient magnetic field can be produced in the inner boundary of the accretion disk. A large amount of rotational energy of the black hole is extracted and released in the ultra relativistic jet with a bulk Lorentz factor larger than 103 via Blandford-Znajek process. The relativistic jet energy can be converted into γ-ray radiation in the shock region located at a distance of about 1.4 × 1016 cm via the external shock mechanism.The observed properties of GRB971214 is used to illustrate our model

  3. Energy Conversion Mechanism for Electron Perpendicular Energy in High Guide-Field Reconnection

    Science.gov (United States)

    Guo, Xuehan; Horiuchi, Ritoku; Kaminou, Yasuhiro; Cheng, Frank; Ono, Yasushi

    2016-10-01

    The energy conversion mechanism for electron perpendicular energy, both the thermal and the kinetic energy, is investigated by means of two-dimensional, full-particle simulations in an open system. It is shown that electron perpendicular heating is mainly due to the breaking of magnetic moment conservation in separatrix region because the charge separation generates intense variation of electric field within the electron Larmor radius. Meanwhile, electron perpendicular acceleration takes place manly due to the polarization drift term as well as the curvature drift term of E . u⊥ in the downstream near the X-point. The enhanced electric field due to the charge separation there results in a significant effect of the polarization drift term on the dissipation of magnetic energy within the ion inertia length in the downstream. Japan Society for the Promotion of Science (JSPS) Fellows 15J03758.

  4. The Potential Energy Landscape and Mechanisms of Diffusion in Liquids

    OpenAIRE

    Keyes, T.; J. Chowdhary

    2001-01-01

    The mechanism of diffusion in supercooled liquids is investigated from the potential energy landscape point of view, with emphasis on the crossover from high- to low-T dynamics. Molecular dynamics simulations with a time dependent mapping to the associated local mininum or inherent structure (IS) are performed on unit-density Lennard-Jones (LJ). New dynamical quantities introduced include r2_{is}(t), the mean-square displacement (MSD) within a basin of attraction of an IS, R2(t), the MSD of t...

  5. Physical Mechanism of Nuclear Reactions at Low Energies

    CERN Document Server

    Oleinik, V P; Arepjev, Yu.D

    2002-01-01

    The physical mechanism of nuclear reactions at low energies caused by spatial extension of electron is considered. Nuclear reactions of this type represent intra-electronic processes, more precisely, the processes occurring inside the area of basic localization of electron. Distinctive characteristics of these processes are defined by interaction of the own field produced by electrically charged matter of electron with free nuclei. Heavy nucleus, appearing inside the area of basic localization of electron, is inevitably deformed because of interaction of protons with the adjoining layers of electronic cloud, which may cause nuclear fission. If there occur "inside" electron two or greater number of light nuclei, an attractive force appears between the nuclei which may result in the fusion of nuclei. The intra-electronic mechanism of nuclear reactions is of a universal character. For its realization it is necessary to have merely a sufficiently intensive stream of free electrons, i.e. heavy electric current, an...

  6. Review of International Experience with Renewable Energy Obligation Support Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, R.

    2005-06-01

    The main policy instruments currently used in the EU Member States to achieve the targets set for electricity produced from renewable energy sources are: (1) the quota obligation system; (2) the feed-in tariff system; and (3) the tendering system. The current study aims to review the experience gained with the quota obligation system. The report provides an overview of the regions where obligation systems have been implemented and contains a detailed evaluation of the performance of the obligation systems in the USA, the UK and in Sweden. The obligation systems in these countries have been evaluated based on the following criteria: Effectiveness; Market efficiency; Certainty for the renewable energy industry; Cost effectiveness; Stakeholder support for the obligation system; and Equity. The evaluation of international experiences with the obligation system gives rise to a mixed picture. Although an obligation in theory is effective and cost effective, it seems too early to conclude that the system delivers these promises in practice. On the one hand this is due to the limited period of implementation that makes it hard to distinguish between the direct effect of the system and some teething problems that will be solved in due time. On the other hand, the conclusion can be drawn that the obligation is a complex system, which will only function well if designed carefully. It does seem worthwhile, however, to continue monitoring the experiences with the obligation system abroad, because this will further reveal whether the system is indeed effective and cost effective in practice. In the longer term, e.g. beyond 2010, the introduction of an obligation system in the Netherlands could be considered. Finally, as the design of support schemes is being improved, it appears that the basic concepts of both the obligation system and the feed in system have been refined in such a way that the two systems are gradually converging. An important difference between the two systems

  7. Micro-cable structured textile for simultaneously harvesting solar and mechanical energy

    KAUST Repository

    Chen, Jun

    2016-09-12

    Developing lightweight, flexible, foldable and sustainable power sources with simple transport and storage remains a challenge and an urgent need for the advancement of next-generation wearable electronics. Here, we report a micro-cable power textile for simultaneously harvesting energy from ambient sunshine and mechanical movement. Solar cells fabricated from lightweight polymer fibres into micro cables are then woven via a shuttle-flying process with fibre-based triboelectric nanogenerators to create a smart fabric. A single layer of such fabric is 320 μm thick and can be integrated into various cloths, curtains, tents and so on. This hybrid power textile, fabricated with a size of 4 cm by 5 cm, was demonstrated to charge a 2 mF commercial capacitor up to 2 V in 1 min under ambient sunlight in the presence of mechanical excitation, such as human motion and wind blowing. The textile could continuously power an electronic watch, directly charge a cell phone and drive water splitting reactions. In light of concerns about global warming and energy crises, searching for renewable energy resources that are not detrimental to the environment is one of the most urgent challenges to the sustainable development of human civilization1,2,3. Generating electricity from natural forces provides a superior solution to alleviate expanding energy needs on a sustainable basis4,5,6,7,8,9. With the rapid advancement of modern technologies, developing lightweight, flexible, sustainable and stable power sources remains both highly desirable and a challenge10,11,12,13,14,15,16. Solar irradiance and mechanical motion are clean and renewable energy sources17,18,19,20,21,22,23,24. Fabric-based materials are most common for humans and fibre-based textiles can effectively accommodate the complex deformations induced by body motion25,26,27,28,29,30,31,32. A smart textile that generates electrical power from absorbed solar irradiance and mechanical motion could be an important

  8. Transfer of mechanical energy during the shot put.

    Science.gov (United States)

    Błażkiewicz, Michalina; Łysoń, Barbara; Chmielewski, Adam; Wit, Andrzej

    2016-09-01

    The aim of this study was to analyse transfer of mechanical energy between body segments during the glide shot put. A group of eight elite throwers from the Polish National Team was analysed in the study. Motion analysis of each throw was recorded using an optoelectronic Vicon system composed of nine infrared camcorders and Kistler force plates. The power and energy were computed for the phase of final acceleration of the glide shot put. The data were normalized with respect to time using the algorithm of the fifth order spline and their values were interpolated with respect to the percentage of total time, assuming that the time of the final weight acceleration movement was different for each putter. Statistically significant transfer was found in the study group between the following segments: Right Knee - Right Hip (p = 0.0035), Left Hip - Torso (p = 0.0201), Torso - Right Shoulder (p = 0.0122) and Right Elbow - Right Wrist (p = 0.0001). Furthermore, the results of cluster analysis showed that the kinetic chain used during the final shot acceleration movement had two different models. Differences between the groups were revealed mainly in the energy generated by the hips and trunk.

  9. Mechanical properties and energy absorption characteristics of a polyurethane foam

    Energy Technology Data Exchange (ETDEWEB)

    Goods, S.H.; Neuschwanger, C.L.; Henderson, C.; Skala, D.M.

    1997-03-01

    Tension, compression and impact properties of a polyurethane encapsulant foam have been measured as a function of foam density. Significant differences in the behavior of the foam were observed depending on the mode of testing. Over the range of densities examined, both the modulus and the elastic collapse stress of the foam exhibited power-law dependencies with respect to density. The power-law relationship for the modulus was the same for both tension and compression testing and is explained in terms of the elastic compliance of the cellular structure of the foam using a simple geometric model. Euler buckling is used to rationalize the density dependence of the collapse stress. Neither tension nor compression testing yielded realistic measurements of energy absorption (toughness). In the former case, the energy absorption characteristics of the foam were severely limited due to the inherent lack of tensile ductility. In the latter case, the absence of a failure mechanism led to arbitrary measures of energy absorption that were not indicative of true material properties. Only impact testing revealed an intrinsic limitation in the toughness characteristics of the material with respect to foam density. The results suggest that dynamic testing should be used when assessing the shock mitigating qualities of a foam.

  10. Segmentally structured disk triboelectric nanogenerator for harvesting rotational mechanical energy.

    Science.gov (United States)

    Lin, Long; Wang, Sihong; Xie, Yannan; Jing, Qingshen; Niu, Simiao; Hu, Youfan; Wang, Zhong Lin

    2013-06-12

    We introduce an innovative design of a disk triboelectric nanogenerator (TENG) with segmental structures for harvesting rotational mechanical energy. Based on a cyclic in-plane charge separation between the segments that have distinct triboelectric polarities, the disk TENG generates electricity with unique characteristics, which have been studied by conjunction of experimental results with finite element calculations. The role played by the segmentation number is studied for maximizing output. A distinct relationship between the rotation speed and the electrical output has been thoroughly investigated, which not only shows power enhancement at high speed but also illuminates its potential application as a self-powered angular speed sensor. Owing to the nonintermittent and ultrafast rotation-induced charge transfer, the disk TENG has been demonstrated as an efficient power source for instantaneously or even continuously driving electronic devices and/or charging an energy storage unit. This work presents a novel working mode of TENGs and opens up many potential applications of nanogenerators for harvesting even large-scale energy.

  11. Energy landscapes, folding mechanisms, and kinetics of RNA tetraloop hairpins.

    Science.gov (United States)

    Chakraborty, Debayan; Collepardo-Guevara, Rosana; Wales, David J

    2014-12-31

    RNA hairpins play a pivotal role in a diverse range of cellular functions, and are integral components of ribozymes, mRNA, and riboswitches. However, the mechanistic and kinetic details of RNA hairpin folding, which are key determinants of most of its biological functions, are poorly understood. In this work, we use the discrete path sampling (DPS) approach to explore the energy landscapes of two RNA tetraloop hairpins, and provide insights into their folding mechanisms and kinetics in atomistic detail. Our results show that the potential energy landscapes have a distinct funnel-like bias toward the folded hairpin state, consistent with efficient structure-seeking properties. Mechanistic and kinetic information is analyzed in terms of kinetic transition networks. We find microsecond folding times, consistent with temperature jump experiments, for hairpin folding initiated from relatively compact unfolded states. This process is essentially driven by an initial collapse, followed by rapid zippering of the helix stem in the final phase. Much lower folding rates are predicted when the folding is initiated from extended chains, which undergo longer excursions on the energy landscape before nucleation events can occur. Our work therefore explains recent experiments and coarse-grained simulations, where the folding kinetics exhibit precisely this dependency on the initial conditions.

  12. Double Higgs mechanisms, supermassive stable particles and the vacuum energy

    Science.gov (United States)

    Santillán, Osvaldo P.; Gabbanelli, Luciano

    2016-07-01

    In the present work, a hidden scenario which cast a long-lived superheavy particle A0 and simultaneously an extremely light particle a with mass ma ˜ 10-32-10-33 eV is presented. The potential energy V (a) of the particle a models the vacuum energy density of the universe ρc ≃ 10-47GeV4. On the other hand, the A0 particle may act as superheavy dark matter at present times and the products of its decay may be observed in high energy cosmic ray events. The hidden sector proposed here include light fermions with masses near the neutrino mass mν ˜ 10-2 eV and superheavy ones with masses of the order of the GUT scale, interacting through a hidden SU(2)L interaction which also affects the ordinary sector. The construction of such combined scenario is nontrivial since the presence of light particles may spoil the stability of the heavy particle A0. However, double Higgs mechanisms may be helpful for overcoming this problem. In this context, the stability of the superheavy particle A0 is ensured due to chiral symmetry arguments elaborated in the text.

  13. Models and mechanisms of energy balance regulation in the young.

    Science.gov (United States)

    Mercer, Julian G

    2008-11-01

    The proportion of the child and adolescent population that is in appropriate energy balance is declining throughout the developed world, and childhood obesity is a particular problem in the UK relative to other northern European countries. Assessment of the underlying causes of obesity, and the different routes to its development, may assist in the definition of successful intervention strategies. The network of peripheral and central (brain) regulatory systems that underlie energy balance and body weight and composition can, for the most part, only be approached experimentally through the study of appropriate laboratory animal models. This problem is particularly acute when the target is overweight and obesity in the young. Some of the mechanisms underlying the development of energy imbalance and specifically the onset of overweight and obesity in the young, and the metabolic health consequences of obesity, can be addressed by examination of experimental rodent models in which mutation of a single gene causes early-onset extreme obesity, genetic susceptibility to obesity is revealed in an obesogenic environment or early-life nutritional experience programmes susceptibility to obesity or metabolic problems in later life. These studies highlight genes that are essential to normal body-weight regulation in rodents and man, the impact of diet and diet-induced obesity on regulatory systems in the young and the potential sensitivity of developing regulatory systems to nutritional experiences in utero and during early life.

  14. Mechanical properties and energy absorption characteristics of a polyurethane foam

    Energy Technology Data Exchange (ETDEWEB)

    Goods, S.H.; Neuschwanger, C.L.; Henderson, C.; Skala, D.M.

    1997-03-01

    Tension, compression and impact properties of a polyurethane encapsulant foam have been measured as a function of foam density. Significant differences in the behavior of the foam were observed depending on the mode of testing. Over the range of densities examined, both the modulus and the elastic collapse stress of the foam exhibited power-law dependencies with respect to density. The power-law relationship for the modulus was the same for both tension and compression testing and is explained in terms of the elastic compliance of the cellular structure of the foam using a simple geometric model. Euler buckling is used to rationalize the density dependence of the collapse stress. Neither tension nor compression testing yielded realistic measurements of energy absorption (toughness). In the former case, the energy absorption characteristics of the foam were severely limited due to the inherent lack of tensile ductility. In the latter case, the absence of a failure mechanism led to arbitrary measures of energy absorption that were not indicative of true material properties. Only impact testing revealed an intrinsic limitation in the toughness characteristics of the material with respect to foam density. The results suggest that dynamic testing should be used when assessing the shock mitigating qualities of a foam.

  15. Transfer of mechanical energy during the shot put

    Directory of Open Access Journals (Sweden)

    Błażkiewicz Michalina

    2016-09-01

    Full Text Available The aim of this study was to analyse transfer of mechanical energy between body segments during the glide shot put. A group of eight elite throwers from the Polish National Team was analysed in the study. Motion analysis of each throw was recorded using an optoelectronic Vicon system composed of nine infrared camcorders and Kistler force plates. The power and energy were computed for the phase of final acceleration of the glide shot put. The data were normalized with respect to time using the algorithm of the fifth order spline and their values were interpolated with respect to the percentage of total time, assuming that the time of the final weight acceleration movement was different for each putter. Statistically significant transfer was found in the study group between the following segments: Right Knee – Right Hip (p = 0.0035, Left Hip - Torso (p = 0.0201, Torso – Right Shoulder (p = 0.0122 and Right Elbow – Right Wrist (p = 0.0001. Furthermore, the results of cluster analysis showed that the kinetic chain used during the final shot acceleration movement had two different models. Differences between the groups were revealed mainly in the energy generated by the hips and trunk.

  16. Soft tissues store and return mechanical energy in human running.

    Science.gov (United States)

    Riddick, R C; Kuo, A D

    2016-02-08

    During human running, softer parts of the body may deform under load and dissipate mechanical energy. Although tissues such as the heel pad have been characterized individually, the aggregate work performed by all soft tissues during running is unknown. We therefore estimated the work performed by soft tissues (N=8 healthy adults) at running speeds ranging 2-5 m s(-1), computed as the difference between joint work performed on rigid segments, and whole-body estimates of work performed on the (non-rigid) body center of mass (COM) and peripheral to the COM. Soft tissues performed aggregate negative work, with magnitude increasing linearly with speed. The amount was about -19 J per stance phase at a nominal 3 m s(-1), accounting for more than 25% of stance phase negative work performed by the entire body. Fluctuations in soft tissue mechanical power over time resembled a damped oscillation starting at ground contact, with peak negative power comparable to that for the knee joint (about -500 W). Even the positive work from soft tissue rebound was significant, about 13 J per stance phase (about 17% of the positive work of the entire body). Assuming that the net dissipative work is offset by an equal amount of active, positive muscle work performed at 25% efficiency, soft tissue dissipation could account for about 29% of the net metabolic expenditure for running at 5 m s(-1). During running, soft tissue deformations dissipate mechanical energy that must be offset by active muscle work at non-negligible metabolic cost.

  17. Activation energies of grain growth mechanisms in aluminum coatings

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, Alan [Lawrence Livermore National Laboratory, Chemistry and Materials Science, CA (United States)]. E-mail: jankowski1@11nl.gov; Ferreira, James [Lawrence Livermore National Laboratory, Chemistry and Materials Science, CA (United States); Hayes, Jeffrey [Lawrence Livermore National Laboratory, Mechanical Engineering, Livermore, CA 94551-9900 (United States)

    2005-11-22

    To produce a specific grain size in metallic coatings requires precise control of the time at temperature during the deposition process. Aluminum coatings are deposited using electron-beam evaporation onto heated substrate surfaces of both mica and lithium flouride. The grain size of the coating is determined upon examination of the microstructure in plan view and cross-section. Ideal grain growth is observed over the entire experimental range of temperature examined from 413 to 843 K. A transition in the activation energy for grain growth from 0.87 to 2.04 eV atom{sup -1} is observed as the temperature increases from < 526 K to > 588 K. The transition is indicative of the dominant mechanism for grain growth shifting with increasing temperature from grain boundary to lattice diffusion.

  18. TC-2 Satellite Delivered

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On April 18, 2005, TC-2, the second satellite of Double Star Program (DSP), which was jointly developed by CNSA and ESA, was approved to be delivered to the user after the on-board test and trial operation. The satellite is working well and the performance can meet the user's need. The satellite has collected large amount of valuable scientific data

  19. Hypoventilation in chronic mountain sickness: a mechanism to preserve energy.

    Science.gov (United States)

    Zubieta-Calleja, G R; Paulev, P-E; Zubieta-Calleja, L; Zubieta-Calleja, N; Zubieta-Castillo, G

    2006-09-01

    Chronic Mountain Sickness (CMS) patients have repeatedly been found to hypoventilate. Low saturation in CMS is attributed to hypoventilation. Although this observation seems logical, a further understanding of the exact mechanism of hypoxia is mandatory. An exercise study using the Bruce Protocol in CMS (n = 13) compared to normals N (n = 17), measuring ventilation (VE), pulse (P), and saturation by pulse oximetry (SaO(2)) was performed. Ventilation at rest while standing, prior to exercise in a treadmill was indeed lower in CMS (8.37 l/min compared with 9.54 l/min in N). However, during exercise, stage one through four, ventilation and cardiac frequency both remained higher than in N. In spite of this, SaO(2) gradually decreased. Although CMS subjects increased ventilation and heart rate more than N, saturation was not sustained, suggesting respiratory insufficiency. The degree of veno-arterial shunting of blood is obviously higher in the CMS patients both at rest and during exercise as judged from the SaO(2) values. The higher shunt fraction is due probably to a larger degree of trapped air in the lungs with uneven ventilation of the CMS patients. One can infer that hypoventilation at rest is an energy saving mechanism of the pneumo-dynamic and hemo-dynamic pumps. Increased ventilation would achieve an unnecessary high SaO(2) at rest (low metabolism). This is particularly true during sleep.

  20. Delivering offshore electricity to the EU. Spatial planning of offshore renewable energies and electricity grid infrastructures in an integrated EU maritime policy

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, L.R.; Veum, K.C.; Hekkenberg, M. [ECN Policy Studies, Petten (Netherlands); Iuga, D.; Moccia, J. [European Wind Energy Association EWEA, Brussels (Belgium); Wagner, A. [Stiftung Offshore Windenergie SOW, Varel (Germany); Kreutzkamp, P.; Jacques, S.; Joseph, P. [3E headquarters, Brussels (Belgium)

    2012-05-15

    Facilitating offshore renewables - wind, wave and tidal - through marine spatial planning (MSP) is the core objective of the Intelligent Energy Europe funded project Seanergy 2020. Seanergy 2020 does this by formulating and promoting policy recommendations on how to best address and remove MSP obstacles to offshore renewable energy generation, in order to implement the EU's Renewable Energy Directive (2009/28/EC). In doing so, it seeks to promote a more integrated and coordinated approach to MSP: that is, an approach that extends beyond national borders. This is particularly important since many human activities as well as ecological concerns at sea have a cross-border dimension. The geographical scope of the Seanergy 2020 project includes the Atlantic Coast and Irish Sea, the Baltic Sea, the Mediterranean Sea, and the North Sea.

  1. PZT thin films for piezoelectric MEMS mechanical energy harvesting

    Science.gov (United States)

    Yeager, Charles

    This thesis describes the optimization of piezoelectric Pb(ZrxTi 1-x)O3 (PZT) thin films for energy generation by mechanical energy harvesting, and self-powered micro-electro-mechanical systems (MEMS). For this purpose, optimization of the material was studied, as was the incorporation of piezoelectric films into low frequency mechanical harvesters. A systematic analysis of the energy harvesting figure of merit was made. As a figure of merit (e31,ƒ)2/epsilon r (transverse piezoelectric coefficient squared over relative permittivity) was utilized. PZT films of several tetragonal compositions were grown on CaF2, MgO, SrTiO3, and Si substrates, thereby separating the dependence of composition on domain orientation. To minimize artifacts associated with composition gradients, and to extend the temperature growth window, PZT films were grown by metal organic chemical vapor deposition (MOCVD). Using this method, epitaxial {001} films achieved c-domain textures above 90% on single crystal MgO and CaF2 substrates. This could be tailored via the thermal stresses established by the differences in thermal expansion coefficients of the film and the substrate. The single-domain e31,ƒ for PZT thin films was determined to exceed -12 C/m2 in the tetragonal phase field for x ≥ 0.19, nearly twice the phenomenologically modeled value. The utilization of c-domain PZT films is motivated by a figure of merit above 0.8 C2/m4 for (001) PZT thin films. Increases to the FoM via doping and hot poling were also quantified; a 1% Mn doping reduced epsilonr by 20% without decreasing the piezoelectric coefficient. Hot poling a device for one hour above 120°C also resulted in a 20% reduction in epsilonr ; furthermore, 1% Mn doping reduced epsilonr by another 12% upon hot poling. Two methods for fabricating thin film mechanical energy harvesting devices were investigated. It was found that phosphoric acid solutions could be used to pattern MgO crystals, but this was typically accompanied by

  2. Effect of mechanical parameters on dielectric elastomer minimum energy structures

    Science.gov (United States)

    Shintake, Jun; Rosset, Samuel; Floreano, Dario; Shea, Herbert R.

    2013-04-01

    Soft robotics may provide many advantages compared to traditional robotics approaches based on rigid materials, such as intrinsically safe physical human-robot interaction, efficient/stable locomotion, adaptive morphology, etc. The objective of this study is to develop a compliant structural actuator for soft a soft robot using dielectric elastomer minimum energy structures (DEMES). DEMES consist of a pre-stretched dielectric elastomer actuator (DEA) bonded to an initially planar flexible frame, which deforms into an out-of-plane shape which allows for large actuation stroke. Our initial goal is a one-dimensional bending actuator with 90 degree stroke. Along with frame shape, the actuation performance of DEMES depends on mechanical parameters such as thickness of the materials and pre-stretch of the elastomer membrane. We report here the characterization results on the effect of mechanical parameters on the actuator performance. The tested devices use a cm-size flexible-PCB (polyimide, 50 μm thickness) as the frame-material. For the DEA, PDMS (approximately 50 μm thickness) and carbon black mixed with silicone were used as membrane and electrode, respectively. The actuators were characterized by measuring the tip angle and the blocking force as functions of applied voltage. Different pre-stretch methods (uniaxial, biaxial and their ratio), and frame geometries (rectangular with different width, triangular and circular) were used. In order to compare actuators with different geometries, the same electrode area was used in all the devices. The results showed that the initial tip angle scales inversely with the frame width, the actuation stroke and the blocking force are inversely related (leading to an interesting design trade-off), using anisotropic pre-stretch increased the actuation stroke and the initial bending angle, and the circular frame shape exhibited the highest actuation performance.

  3. Low Energy Electrons as Probing Tool for Astrochemical Reaction Mechanisms

    Science.gov (United States)

    Hendrik Bredehöft, Jan; Swiderek, Petra; Hamann, Thorben

    The complexity of molecules found in space varies widely. On one end of the scale of molecular complexity is the hydrogen molecule H2 . Its formation from H atoms is if not understood than at least thoroughly investigated[1]. On the other side of said spectrum the precursors to biopolymers can be found, such as amino acids[2,3], sugars[4], lipids, cofactors[5], etc, and the kerogen-like organic polymer material in carbonaceous meteorites called "black stuff" [6]. These have also received broad attention in the last decades. Sitting in the middle between these two extremes are simple molecules that are observed by radio astronomy throughout the Universe. These are molecules like methane (CH4 ), methanol (CH3 OH), formaldehyde (CH2 O), hydrogen cyanide (HCN), and many many others. So far more than 40 such species have been identified.[7] They are often used in laboratory experiments to create larger complex molecules on the surface of simulated interstellar dust grains.[2,8] The mechanisms of formation of these observed starting materials for prebiotic chemistry is however not always clear. Also the exact mechanisms of formation of larger molecules in photochemical experiments are largely unclear. This is mostly due to the very complex chemistry going on which involves many different radicals and ions. The creation of radicals and ions can be studied in detail in laboratory simulations. They can be created in a setup mimicking interstellar grain chemistry using slow electrons. There is no free electron radiation in space. What can be found though is a lot of radiation of different sorts. There is electromagnetic radiation (UV light, X-Rays, rays, etc.) and there is particulate radiation as well in the form of high energy ions. This radiation can provide energy that drives chemical reactions in the ice mantles of interstellar dust grains. And while the multitude of different kinds of radiation might be a little confusing, they all have one thing in common: Upon

  4. An industrial heating plant that delivers water at high temperatures and incorporates a mechanical compressor for beer vapor. Blockheizkraftwerk mit hohen Nutz-Wassertemperaturen und mechanischer Bruedenverdichtungsanlage

    Energy Technology Data Exchange (ETDEWEB)

    Klemm, W. (Stuttgarter Hofbraeu AG, Stuttgart (Germany)); Grosshans, D. (Technische Werke der Stadt Stuttgart AG (Germany))

    1992-03-01

    A new approach to energy utilization at the Stuttgarter Hofbraeu AG brewery is highlighted. Fired by natural gas, the power plant comprises a hot water reservoir and a compressor for beer vapor. Its special features at the high (140deg C) temperature of circulating water and efficient fuel consumption. Initial performance data for the plant, which was placed in service at the end of 1990, are now available. In June, 1991 the city of Stuttgart conferred its first environmental award on the plant. (orig.).

  5. Dysregulation of energy balance by trichothecene mycotoxins: Mechanisms and prospects.

    Science.gov (United States)

    Lebrun, Bruno; Tardivel, Catherine; Félix, Bernadette; Abysique, Anne; Troadec, Jean-Denis; Gaigé, Stéphanie; Dallaporta, Michel

    2015-07-01

    Trichothecenes are toxic metabolites produced by fungi that constitute a worldwide hazard for agricultural production and both animal and human health. More than 40 countries have introduced regulations or guidelines for food and feed contamination levels of the most prevalent trichothecene, deoxynivalenol (DON), on the basis of its ability to cause growth suppression. With the development of analytical tools, evaluation of food contamination and exposure revealed that a significant proportion of the human population is chronically exposed to DON doses exceeding the provisional maximum tolerable daily dose. Accordingly, a better understanding of trichothecene impact on health is needed. Upon exposure to low or moderate doses, DON and other trichothecenes induce anorexia, vomiting and reduced weight gain. Several recent studies have addressed the mechanisms by which trichothecenes induce these symptoms and revealed a multifaceted action targeting gut, liver and brain and causing dysregulation in neuroendocrine signaling, immune responses, growth hormone axis, and central neurocircuitries involved in energy homeostasis. Newly identified trichothecene toxicosis biomarkers are just beginning to be exploited and already open up new questions on the potential harmful effects of chronic exposure to DON at apparently asymptomatic very low levels. This review summarizes our current understanding of the effects of DON and other trichothecenes on food intake and weight growth.

  6. Cytogenetic Reconstruction of Gamma-Ray Doses Delivered to Atomic Bomb Survivors: Dealing with Wide Distributions of Photon Energies and Contributions from Hematopoietic Stem/Progenitor Cells.

    Science.gov (United States)

    Nakamura, Nori; Hirai, Yuko; Kodama, Yoshiaki; Hamasaki, Kanya; Cullings, Harry M; Cordova, Kismet A; Awa, Akio

    2017-08-11

    Retrospective estimation of the doses received by atomic bomb (A-bomb) survivors by cytogenetic methods has been hindered by two factors: One is that the photon energies released from the bomb were widely distributed, and since the aberration yield varies depending on the energy, the use of monoenergetic (60)Co gamma radiation to construct a calibration curve may bias the estimate. The second problem is the increasing proportion of newly formed lymphocytes entering into the lymphocyte pool with increasing time intervals since the exposures. These new cells are derived from irradiated precursor/stem cells whose radiosensitivity may differ from that of blood lymphocytes. To overcome these problems, radiation doses to tooth enamel were estimated using the electron spin resonance (ESR; or EPR, electron paramagnetic resonance) method and compared with the cytogenetically estimated doses from the same survivors. The ESR method is only weakly dependent on the photon energy and independent of the years elapsed since an exposure. Both ESR and cytogenetic doses were estimated from 107 survivors. The latter estimates were made by assuming that although a part of the cells examined could be lymphoid stem or precursor cells at the time of exposure, all the cells had the same radiosensitivity as blood lymphocytes, and that the A-bomb gamma-ray spectrum was the same as that of the (60)Co gamma rays. Subsequently, ESR and cytogenetic endpoints were used to estimate the kerma doses using individual DS02R1 information on shielding conditions. The results showed that the two sets of kerma doses were in close agreement, indicating that perhaps no correction is needed in estimating atomic bomb gamma-ray doses from the cytogenetically estimated (60)Co gamma-ray equivalent doses. The present results will make it possible to directly compare cytogenetic doses with the physically estimated doses of the survivors, which would pave the way for testing whether or not there are any systematic

  7. Reorganization energy, activation energy, and mechanism of hole transfer process in DNA: a theoretical study.

    Science.gov (United States)

    Khan, Arshad

    2008-02-21

    The density functional calculations with aug-cc-pVDZ basis sets on cationic guanine-cytosine (GC(+)) and adenine-thymine (AT(+)) base pairs suggest that the cationic charge is almost entirely localized on the G and A units with significant changes in the N-H and N...O distances around the H-bonded area. While the calculated intramolecular reorganization energy (lambda(v)) for a GC base pair (0.75 eV) is remarkably larger than that for an isolated G base (0.49 eV), for the AT base pairs these values (0.44 and 0.40 eV) are almost the same. The gas phase activation energies (E(a)) for GC(+)GC-->GCGC(+), AT(+)AT-->ATAT(+), and GC(+)AT-->GCAT(+) hole transfer processes are 0.19, 0.11, and 0.73 eV with rate constants of 1.69 x 10(11), 3.15 x 10(11), and 4.61(0.168) s(-1), respectively, at 298 K. An alternative mechanism of hole transfer has been proposed on the basis of energy barriers.

  8. Energy transfer properties and mechanisms. Technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    Barker, J.R.

    1995-02-03

    Collisional energy transfer is the controlling factor in many nonequilibrium chemical systems: combustion, laser-induced chemical reactions, shock-heated gases, atmospheric chemistry, etc. During this period, efforts were made in 3 areas: large molecule energy transfer experiments (organic compounds); triatomic V-T/R energy transfer (memory effects); and energy transfer in extreme environments (shock tube data on norbornene). Results are described very briefly.

  9. Whey protein effects on energy balance link the intestinal mechanisms of energy absorption with adiposity and hypothalamic neuropeptide gene expression.

    Science.gov (United States)

    Nilaweera, Kanishka N; Cabrera-Rubio, Raul; Speakman, John R; O'Connor, Paula M; McAuliffe, AnneMarie; Guinane, Caitriona M; Lawton, Elaine M; Crispie, Fiona; Aguilera, Mònica; Stanley, Maurice; Boscaini, Serena; Joyce, Susan; Melgar, Silvia; Cryan, John F; Cotter, Paul D

    2017-07-01

    We tested the hypothesis that dietary whey protein isolate (WPI) affects the intestinal mechanisms related to energy absorption and that the resulting energy deficit is compensated by changes in energy balance to support growth. C57BL/6 mice were provided a diet enriched with WPI with varied sucrose content, and the impact on energy balance-related parameters was investigated. As part of a high-sucrose diet, WPI reduced the hypothalamic expression of pro-opiomelanocortin gene expression and increased energy intake. The energy expenditure was unaffected, but epididymal weight was reduced, indicating an energy loss. Notably, there was a reduction in the ileum gene expression for amino acid transporter SLC6a19, glucose transporter 2, and fatty acid transporter 4. The composition of the gut microbiota also changed, where Firmicutes were reduced. The above changes indicated reduced energy absorption through the intestine. We propose that this mobilized energy in the adipose tissue and caused hypothalamic changes that increased energy intake, acting to counteract the energy deficit arising in the intestine. Lowering the sucrose content in the WPI diet increased energy expenditure. This further reduced epididymal weight and plasma leptin, whereupon hypothalamic ghrelin gene expression and the intestinal weight were both increased. These data suggest that when the intestine-adipose-hypothalamic pathway is subjected to an additional energy loss (now in the adipose tissue), compensatory changes attempt to assimilate more energy. Notably, WPI and sucrose content interact to enable the component mechanisms of this pathway. Copyright © 2017 the American Physiological Society.

  10. Hints on the high-energy seesaw mechanism from the low-energy neutrino spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Casas, J.A.; Jimenez-Alburquerque, F. [Univ. Autonoma de Madrid (Spain). IFT-UAM/CSIC, C-XVI; Ibarra, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2006-12-15

    It is an experimental fact that the mass ratio for the two heavier neutrinos, h=m{sub 3}/m{sub 2}mechanism, determining 1) How the present experimental data restrict the structure of the high-energy seesaw parameters and 2) Which choices, among the allowed ones, produce more naturally the observed pattern of neutrino masses. We have studied in particular if starting with hierarchical neutrino Yukawa couplings, as for the other fermions, one can naturally get the observed hmechanism in terms of (high-energy) basis-independent quantities. Among the main results, we find that in most cases m{sub 3}/m{sub 2} >> m{sub 3}/m{sub 2}, so m{sub 1} should be extremely tiny. Also, the V{sub R} matrix associated to the neutrino Yukawa couplings has a far from random structure, naturally resembling V{sub CKM}. In fact we show that identifying V{sub R} and V{sub CKM}, as well as neutrino and u-quark Yukawa couplings can reproduce h{sup exp} in a highly non-trivial way, which is very suggestive. The physical implications of these results are also discussed. (orig.)

  11. 1000th magnet delivered!

    CERN Multimedia

    2006-01-01

    On Monday 20 February members of the AT Department marked the delivery of the 1000th superconducting dipole magnet to CERN. Only 232 more of the dipole magnets are needed for the LHC. The 35-tonne-dipoles are 15 meters long and are being manufactured by three companies: Babcock Noell Nuclear in Germany (which completed its contract in November 2005), Ansaldo Superconduttori in Italy and Alstom-Jeumont in France. 'The production is proceeding well and we expect to be complete in October as foreseen,' said Lucio Rossi, Head of the Magnets and Superconductors Group (AT-MAS). In total, 1650 main magnets are needed for the LHC, of which 1300 have already been delivered.

  12. 1000th magnet delivered!

    CERN Multimedia

    2006-01-01

    On Monday 20 February members of the AT Department marked the delivery of the 1000th superconducting dipole magnet to CERN. Only 232 more of the dipole magnets are needed for the LHC. The 35 tonne-dipoles are 15 meters long and are being manufactured by three companies: Babcock Noell Nuclear in Germany (which finished its contract in November 2005), Ansaldo Superconduttori in Italy and Alstom-Jeumont in France. "The production is proceeding well and we expect to be complete in October as previously foreseen," said Lucio Rossi, Head of the Magnets and Superconductors Group (AT-MAS). In total, 1650 main magnets are needed for the LHC, of which 1300 have been delivered.

  13. Energy conservation in mechanical industry; Maitrise de l`energie dans les industries mecaniques

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The workshop is composed of 12 communications on the theme of energy consumption, conservation and management in industry, and more especially in metal industry: evaluation of the energy savings potential in the French industry; official energy diagnosis procedure in buildings; the French national gas utility policy for energy conservation and economical performance in industry; energy conservation with speed variators for electric motors; energy audits and energy metering for conservation objectives. Examples of energy efficient systems or energy audits in various industrial sectors (compressed air, industrial buildings, heat treatments, curing...) are also presented. The electric power quality EDF`s contract is also discussed

  14. Renormalizing the Kinetic Energy Operator in Elementary Quantum Mechanics

    Science.gov (United States)

    Coutinho, F. A. B.; Amaku, M.

    2009-01-01

    In this paper, we consider solutions to the three-dimensional Schrodinger equation of the form [psi](r) = u(r)/r, where u(0) [is not equal to] 0. The expectation value of the kinetic energy operator for such wavefunctions diverges. We show that it is possible to introduce a potential energy with an expectation value that also diverges, exactly…

  15. Renormalizing the Kinetic Energy Operator in Elementary Quantum Mechanics

    Science.gov (United States)

    Coutinho, F. A. B.; Amaku, M.

    2009-01-01

    In this paper, we consider solutions to the three-dimensional Schrodinger equation of the form [psi](r) = u(r)/r, where u(0) [is not equal to] 0. The expectation value of the kinetic energy operator for such wavefunctions diverges. We show that it is possible to introduce a potential energy with an expectation value that also diverges, exactly…

  16. Preliminary study on mechanics-based rainfall kinetic energy

    Directory of Open Access Journals (Sweden)

    Yuan Jiuqin Ms.

    2014-09-01

    Full Text Available A raindrop impact power observation system was employed to observe the real-time raindrop impact power during a rainfall event and to analyze the corresponding rainfall characteristics. The experiments were conducted at different simulated rainfall intensities. As rainfall intensity increased, the observed impact power increased linearly indicating the power observation system would be satisfactory for characterizing rainfall erosivity. Momentum is the product of mass and velocity (Momentum=MV, which is related to the observed impact power value. Since there is no significant difference between momentum and impact power, observed impact power can represent momentum for different rainfall intensities. The relationship between momentum and the observed impact power provides a convenient way to calculate rainfall kinetic energy. The value of rainfall kinetic energy based on the observed impact power was higher than the classic rainfall kinetic energy. The rainfall impact power based kinetic energy and the classic rainfall kinetic energy showed linear correlation, which indicates that the raindrop impact power observation system can characterize rainfall kinetic energy. The article establishes a preliminary way to calculate rainfall kinetic energy by using the real-time observed momentum, providing a foundation for replacing the traditional methods for estimating kinetic energy of rainstorms.

  17. Mechanism of action of a desensitizing fluoride toothpaste delivering calcium and phosphate ingredients in the treatment of dental hypersensitivity. Part II: comparison with a professional treatment for tooth hypersensitivity.

    Science.gov (United States)

    Charig, Andrew J; Thong, Stephen; Flores, Florita; Gupta, Shivank; Major, Elizabeth; Winston, Anthony E

    2009-01-01

    Tooth hypersensitivity can occur when gum recession causes exposure of dentin. Tiny tubules, which permeate dentin, provide open passageways from the mouth to the intradental nerve in the pulpal cavity. Under such circumstances, stimuli in the mouth can cause pressure on the intradental nerve, leading to pain. Sealing the outside of the tubules with an impermeable substance can effectively treat hypersensitivity. One such clinically proven composition is a professionally applied tooth desensitizer, which has been shown to initially produce a layer of amorphous calcium phosphate (ACP) on the surface of dentin. Under the influence of fluoride, ACP reforms as hydroxyapatite (HAP), which has essentially the same composition as tooth mineral. Three fluoride toothpastes that deliver calcium and phosphate salts to the teeth also have been demonstrated in clinical trials to relieve hypersensitivity. This study compared the mechanism of action of these toothpastes to that of the professional desensitizer. A single application of the professional desensitizer or multiple applications of any of the three toothpastes was shown to reduce dentin permeability. A conventional fluoride toothpaste also was found to inhibit fluid flow through the dentin but to a lesser degree than the other toothpastes. The desensitizer and the three toothpastes were found to occlude the dentinal tubules with a layer of calcium phosphate that had a calcium-to-phosphate ratio consistent with the formation of ACP or HAP. The morphology of the coherent mineral layer formed by Arm & Hammer Enamel Care Sensitive was similar, especially to that produced by the desensitizer. In contrast, the conventional toothpaste left localized areas of surface residue composed of silica particles. The mechanism of action of the three toothpastes that deliver calcium and phosphate salts is the same as that of the professional desensitizer.

  18. Renormalizing the kinetic energy operator in elementary quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Coutinho, F A B [Faculdade de Medicina, Universidade de Sao Paulo e LIM 01-HCFMUSP, 05405-000 Sao Paulo (Brazil); Amaku, M [Faculdade de Medicina Veterinaria e Zootecnia, Universidade de Sao Paulo, 05508-970 Sao Paulo (Brazil)], E-mail: coutinho@dim.fm.usp.br

    2009-09-15

    In this paper, we consider solutions to the three-dimensional Schroedinger equation of the form {psi}(r) = u(r)/r, where u(0) {ne} 0. The expectation value of the kinetic energy operator for such wavefunctions diverges. We show that it is possible to introduce a potential energy with an expectation value that also diverges, exactly cancelling the kinetic energy divergence. This renormalization procedure produces a self-adjoint Hamiltonian. We solve some problems with this new Hamiltonian to illustrate its usefulness.

  19. Mechanical energy and mean equivalent viscous damping for SDOF fractional oscillators

    CERN Document Server

    Yuan, Jian; Gai, Mingjiu; Yang, Shujie

    2016-01-01

    This paper addresses the total mechanical energy of a single degree of freedom fractional oscillator. Based on the energy storage and dissipation properties of the Caputo fractional derivatives, the expression for total mechanical energy in the single degree of freedom fractional oscillator is firstly presented. The energy regeneration due to the external exciting force and the energy loss due to the fractional damping force during the vibratory motion are analyzed. Furthermore, based on the mean energy dissipation of the fractional damping element in steady-state vibration, a new concept of mean equivalent viscous damping is suggested and the value of the damping coefficient is evaluated.

  20. Reducing barriers to energy efficiency in the German mechanical engineering sector. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schleich, J.; Boede, U.

    2000-12-01

    This report describes the empirical research into barriers to energy efficiency in the German mechanical engineering (ME) sector. It is one of nine such reports in the BARRIERS project. The report contains description and analysis of four case studies of energy management in German companies in the ME sector. The results are analysed using the theoretical framework developed for the BARRIERS project. The report also provides brief recommendations on how these barriers to the rational use of energy (RUE) may be overcome and how energy efficiency within the ME sector may be improved. The results of the study for the ME sector in Germany are summarised in this executive summary under the following headings: - Characterising the mechanical engineering sector; - Case studies of energy management in the German mechanical engineering sector; - Evidence of barriers in the German mechanical engineering sector; - The role of energy service companies in the mechanical engineering sector; - Policy implications. (orig.)

  1. Reducing barriers to energy efficiency in the German mechanical engineering sector. Executive summary

    Energy Technology Data Exchange (ETDEWEB)

    Schleich, J.; Boede, U.

    2000-12-01

    This report describes the empirical research into barriers to energy efficiency in the German mechanical engineering (ME) sector. It is one of nine such reports in the BARRIERS project. The report contains description and analysis of four case studies of energy management in German companies in the ME sector. The results are analysed using the theoretical framework developed for the BARRIERS project. The report also provides brief recommendations on how these barriers to the rational use of energy (RUE) may be overcome and how energy efficiency within the ME sector may be improved. The results of the study for the ME sector in Germany are summarised in this executive summary under the following headings: - Characterising the mechanical engineering sector; - Case studies of energy management in the German mechanical engineering sector; - Evidence of barriers in the German mechanical engineering sector; - The role of energy service companies in the mechanical engineering sector; - Policy implications. (orig.)

  2. Delivering SKA Science

    CERN Document Server

    Quinn, Peter; Bird, Ian; Dodson, Richard; Szalay, Alex; Wicenec, Andreas

    2015-01-01

    The SKA will be capable of producing a stream of science data products that are Exa-scale in terms of their storage and processing requirements. This Google-scale enterprise is attracting considerable international interest and excitement from within the industrial and academic communities. In this chapter we examine the data flow, storage and processing requirements of a number of key SKA survey science projects to be executed on the baseline SKA1 configuration. Based on a set of conservative assumptions about trends for HPC and storage costs, and the data flow process within the SKA Observatory, it is apparent that survey projects of the scale proposed will potentially drive construction and operations costs beyond the current anticipated SKA1 budget. This implies a sharing of the resources and costs to deliver SKA science between the community and what is contained within the SKA Observatory. A similar situation was apparent to the designers of the LHC more than 10 years ago. We propose that it is time for...

  3. Experimental study on the fabrication of advanced materials for energy applications using high energy mechanical milling

    Science.gov (United States)

    Narayana Swamy, Ashvin Kumar

    The reaction of aluminum (Al) powder with water has the potential for on demand hydrogen generation. Conventional Al powders, however, react with water slowly due to a highly protective oxide layer on the particle surface. Current methods for Al activation involve harmful and expensive materials. The nano-scale Al powders also remain very expensive and have problems such as a large amount of oxide on the surface. The use of aluminum in an energy generation cycle is also hindered by the fact that, although Al is the most abundant metal in the Earth's crust, its recovery from ore consumes a lot of energy. Recycling aluminum hydroxide, formed as a result of Al reaction with water, would also require large amounts of energy. The energy consumption for production of Al powder and hence its cost could be significantly reduced by using recycled aluminum scrap and waste where aluminum is contained in metallic, non-oxidized form. The research work presented here investigates the preparation of an activated aluminum powder from aluminum foil that is widely available as scrap and waste. The obtained results demonstrate that a highly reactive, fine powder can be obtained from Al foil by high-energy ball milling with sodium chloride (NaCl). The obtained powder readily reacts with hot water, releasing hydrogen. Note that NaCl is an environment-friendly additive that can easily be removed after milling and recycled. After washing NaCl out, the powders retain a high reactivity with respect to hot water. As compared to previously studied activation of commercial Al powders, a major advantage of the investigated process is the feasibility of using secondary aluminum. Another area of research presented here is the synthesis of gallium oxide (Ga2O3) nanostructures for their use as high-temperature sensors. Quasi one-dimensional nanomaterials are of great interest due to increased focus on their importance in physics research and also their applications in the nanodevices industry

  4. Energy Efficiency Investments in Public Facilities - Developing a Pilot Mechanism for Energy Performance Contracts (EPCs) in Russia

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Meredydd; Roshchanka, Volha; Parker, Steven A.; Baranovskiy, Aleksandr

    2012-02-01

    : Russian public sector buildings tend to be very inefficient, which creates vast opportunities for savings. This report overviews the latest developments in the Russian legislation related to energy efficiency in the public sector, describes the major challenges the regulations pose, and proposes ways to overcome these challenges. Given Russia’s limited experience with energy performance contracts (EPCs), a pilot project can help test an implementation mechanism. This paper discusses how EPCs and other mechanisms can help harness energy savings opportunities in Russia in general, and thus, can be applicable to any Russian region.

  5. The quantum mechanics based on a general kinetic energy

    CERN Document Server

    Wei, Yuchuan

    2016-01-01

    In this paper, we introduce the Schrodinger equation with a general kinetic energy operator. The conservation law is proved and the probability continuity equation is deducted in a general sense. Examples with a Hermitian kinetic energy operator include the standard Schrodinger equation, the relativistic Schrodinger equation, the fractional Schrodinger equation, the Dirac equation, and the deformed Schrodinger equation. We reveal that the Klein-Gordon equation has a hidden non-Hermitian kinetic energy operator. The probability continuity equation with sources indicates that there exists a different way of probability transportation, which is probability teleportation. An average formula is deducted from the relativistic Schrodinger equation, the Dirac equation, and the K-G equation.

  6. Simulated scaling method for localized enhanced sampling and simultaneous "alchemical" free energy simulations: a general method for molecular mechanical, quantum mechanical, and quantum mechanical/molecular mechanical simulations.

    Science.gov (United States)

    Li, Hongzhi; Fajer, Mikolai; Yang, Wei

    2007-01-14

    A potential scaling version of simulated tempering is presented to efficiently sample configuration space in a localized region. The present "simulated scaling" method is developed with a Wang-Landau type of updating scheme in order to quickly flatten the distributions in the scaling parameter lambdam space. This proposal is meaningful for a broad range of biophysical problems, in which localized sampling is required. Besides its superior capability and robustness in localized conformational sampling, this simulated scaling method can also naturally lead to efficient "alchemical" free energy predictions when dual-topology alchemical hybrid potential is applied; thereby simultaneously, both of the chemically and conformationally distinct portions of two end point chemical states can be efficiently sampled. As demonstrated in this work, the present method is also feasible for the quantum mechanical and quantum mechanical/molecular mechanical simulations.

  7. Direct design of an energy landscape with bistable DNA origami mechanisms.

    Science.gov (United States)

    Zhou, Lifeng; Marras, Alexander E; Su, Hai-Jun; Castro, Carlos E

    2015-03-11

    Structural DNA nanotechnology provides a feasible technique for the design and fabrication of complex geometries even exhibiting controllable dynamic behavior. Recently we have demonstrated the possibility of implementing macroscopic engineering design approaches to construct DNA origami mechanisms (DOM) with programmable motion and tunable flexibility. Here, we implement the design of compliant DNA origami mechanisms to extend from prescribing motion to prescribing an energy landscape. Compliant mechanisms facilitate motion via deformation of components with tunable stiffness resulting in well-defined mechanical energy stored in the structure. We design, fabricate, and characterize a DNA origami nanostructure with an energy landscape defined by two stable states (local energy minima) separated by a designed energy barrier. This nanostructure is a four-bar bistable mechanism with two undeformed states. Traversing between those states requires deformation, and hence mechanical energy storage, in a compliant arm of the linkage. The energy barrier for switching between two states was obtained from the conformational distribution based on a Boltzmann probability function and closely follows a predictive mechanical model. Furthermore, we demonstrated the ability to actuate the mechanism into one stable state via additional DNA inputs and then release the actuation via DNA strand displacement. This controllable multistate system establishes a foundation for direct design of energy landscapes that regulate conformational dynamics similar to biomolecular complexes.

  8. Exact Ultra Cold Neutrons' Energy Spectrum in Gravitational Quantum Mechanics

    CERN Document Server

    Pedram, Pouria

    2013-01-01

    We find exact energy eigenvalues and eigenfunctions of the quantum bouncer in the presence of the minimal length uncertainty and the maximal momentum. This form of Generalized (Gravitational) Uncertainty Principle (GUP) agrees with various theories of quantum gravity and predicts a minimal length uncertainty proportional to $\\hbar\\sqrt{\\beta}$ and a maximal momentum proportional to $1/\\sqrt{\\beta}$, where $\\beta$ is the deformation parameter. We also find the semiclassical energy spectrum and discuss the effects of this GUP on the transition rate of the ultra cold neutrons in gravitational spectrometers. Then, based on the Nesvizhevsky's famous experiment, we obtain an upper bound on the dimensionless GUP parameter.

  9. Exact ultra cold neutrons' energy spectrum in gravitational quantum mechanics

    Science.gov (United States)

    Pedram, Pouria

    2013-10-01

    We find exact energy eigenvalues and eigenfunctions of the quantum bouncer in the presence of the minimal length uncertainty and the maximal momentum. This form of Generalized (Gravitational) Uncertainty Principle (GUP) agrees with various theories of quantum gravity and predicts a minimal length uncertainty proportional to and a maximal momentum proportional to , where β is the deformation parameter. We also find the semiclassical energy spectrum and discuss the effects of this GUP on the transition rate of the ultra cold neutrons in gravitational spectrometers. Then, based on Nesvizhevsky's famous experiment, we obtain an upper bound on the dimensionless GUP parameter.

  10. From mechanical folding trajectories to intrinsic energy landscapes of biopolymers

    Science.gov (United States)

    Hinczewski, Michael; Gebhardt, J. Christof M.; Rief, Matthias; Thirumalai, D.

    2013-01-01

    In single-molecule laser optical tweezer (LOT) pulling experiments, a protein or RNA is juxtaposed between DNA handles that are attached to beads in optical traps. The LOT generates folding trajectories under force in terms of time-dependent changes in the distance between the beads. How to construct the full intrinsic folding landscape (without the handles and beads) from the measured time series is a major unsolved problem. By using rigorous theoretical methods—which account for fluctuations of the DNA handles, rotation of the optical beads, variations in applied tension due to finite trap stiffness, as well as environmental noise and limited bandwidth of the apparatus—we provide a tractable method to derive intrinsic free-energy profiles. We validate the method by showing that the exactly calculable intrinsic free-energy profile for a generalized Rouse model, which mimics the two-state behavior in nucleic acid hairpins, can be accurately extracted from simulated time series in a LOT setup regardless of the stiffness of the handles. We next apply the approach to trajectories from coarse-grained LOT molecular simulations of a coiled-coil protein based on the GCN4 leucine zipper and obtain a free-energy landscape that is in quantitative agreement with simulations performed without the beads and handles. Finally, we extract the intrinsic free-energy landscape from experimental LOT measurements for the leucine zipper. PMID:23487746

  11. Damped Mechanical Oscillator: Experiment and Detailed Energy Analysis

    Science.gov (United States)

    Corridoni, Tommaso; D'Anna, Michele; Fuchs, Hans

    2014-01-01

    The damped oscillator is discussed in every high school textbook or introductory physics course, and a large number of papers are devoted to it in physics didactics journals. Papers typically focus on kinematic and dynamic aspects and less often on energy. Among the latter, some are devoted to the peculiar decreasing behavior of energy…

  12. Mechanism of active transport: free energy dissipation and free energy transduction.

    OpenAIRE

    Tanford, C

    1982-01-01

    The thermodynamic pathway for "chemiosmotic" free energy transduction in active transport is discussed with an ATP-driven Ca2+ pump as an illustrative example. Two innovations are made in the analysis. (i) Free energy dissipated as heat is rigorously excluded from overall free energy bookkeeping by focusing on the dynamic equilibrium state of the chemiosmotic process. (ii) Separate chemical potential terms for free energy donor and transported ions are used to keep track of the thermodynamic ...

  13. Queueing Delay and Energy Efficiency Analyses of Sleep Based Power Saving Mechanism

    Science.gov (United States)

    Zhu, Fan; Wu, Yiqun; Niu, Zhisheng

    In wireless networks, sleep mode based power saving mechanisms can reduce the energy consumption at the expense of additional packet delay. This letter analyzes its packet queueing delay and wireless terminals' energy efficiency. Based on the analysis, optimal sleep window size can be derived to optimize terminal energy efficiency with delay constraint.

  14. Patterns of Selection of Human Movements III: Energy Efficiency, Mechanical Advantage, and Walking Gait

    OpenAIRE

    Hagler, Stuart

    2016-01-01

    Human movements are physical processes combining the classical mechanics of the human body moving in space and the biomechanics of the muscles generating the forces acting on the body under sophisticated sensory-motor control. One way to characterize movement performance is through measures of energy efficiency that relate the mechanical energy of the body and metabolic energy expended by the muscles. We expect the practical utility of such measures to be greater when human subjects execute m...

  15. The calculation of mechanical energy loss for incompressible steady pipe flow of homogeneous fluid

    Institute of Scientific and Technical Information of China (English)

    刘士和; 薛娇; 范敏

    2013-01-01

    The calculation of the mechanical energy loss is one of the fundamental problems in the field of Hydraulics and Enginee- ring Fluid Mechanics. However, for a non-uniform flow the relation between the mechanical energy loss in a volume of fluid and the kinematical and dynamical characteristics of the flow field is not clearly established. In this paper a new mechanical energy equation for the incompressible steady non-uniform pipe flow of homogeneous fluid is derived, which includes the variation of the mean tur- bulent kinetic energy, and the formula for the calculation of the mechanical energy transformation loss for the non-uniform flow bet- ween two cross sections is obtained based on this equation. This formula can be simplified to the Darcy-Weisbach formula for the uniform flow as widely used in Hydraulics. Furthermore, the contributions of the mechanical energy loss relative to the time avera- ged velocity gradient and the dissipation of the turbulent kinetic energy in the turbulent uniform pipe flow are discussed, and the con- tributions of the mechanical energy loss in the viscous sublayer, the buffer layer and the region above the buffer layer for the turbu- lent uniform flow are also analyzed.

  16. Impact of Offshore Wind Energy Plants on the Soil Mechanical Behaviour of Sandy Seafloors

    Science.gov (United States)

    Stark, Nina; Lambers-Huesmann, Maria; Zeiler, Manfred; Zoellner, Christian; Kopf, Achim

    2010-05-01

    Over the last decade, wind energy has become an important renewable energy source. Especially, the installation of offshore windfarms offers additional space and higher average wind speeds than the well-established windfarms onshore. Certainly, the construction of offshore wind turbines has an impact on the environment. In the framework of the Research at Alpha VEntus (RAVE) project in the German offshore wind energy farm Alpha Ventus (north of the island Borkum in water depths of about 30 m) a research plan to investigate the environmental impact had been put into place. An ongoing study focuses on the changes in soil mechanics of the seafloor close to the foundations and the development of scour. Here, we present results of the first geotechnical investigations after construction of the plants (ca. 1 - 6 months) compared to geotechnical measurements prior to construction. To study the soil mechanical behaviour of the sand, sediment samples from about thirty different positions were measured in the laboratory to deliver, e.g., grain size (0.063 - 0.3 mm), friction angles (~ 32°), unit weight (~ 19.9 kN/m³) and void ratios (~ 0.81). For acoustic visualisation, side-scan-sonar (towed and stationary) and multibeam-echosounders (hull mounted) were used. Data show a flat, homogenous seafloor prior to windmill erection, and scouring effects at and in the vicinity of the foundations afterwards. Geotechnical in-situ measurements were carried out using a standard dynamic Cone Penetration Testing lance covering the whole windfarm area excluding areas in a radius 50 %) occur above all close to the foundations. Furthermore, patterns of relatively soft zones (qsbc.: 50 - 80 kPa) and hard zones (qsbc. > 100 kPa) were mapped during the high-resolution surveys close to the foundation. Beside that, a very soft sediment layer (0.03 - 0.05 m) drapes most of the soft zones. This may be recently eroded and re-deposited sediment, whereas the hard zones may indicate areas of sediment

  17. Comparing global coordination mechanisms on energy, environment, and water

    NARCIS (Netherlands)

    Schubert, S.; Gupta, J.

    2013-01-01

    Increasingly, coordination mechanisms are being created at the United Nations (UN) level to enhance system-wide synergies; however, there is relatively little scientific research on these bodies. Against this background, we compare the mandates, structures, and outputs of three UN coordination mecha

  18. Industrial waste exchange: a mechanism for saving energy and money

    Energy Technology Data Exchange (ETDEWEB)

    Gaines, L.L.

    1983-01-01

    Although considerable savings of both energy and money are possible through waste exchange, several major impediments limit the number of actual exchanges that take place. These impediments include the lack of economical separation technology, the small quantities of material available at each site, restrictive or uncertain regulation, and lack of knowledge on the part of potential waste users. None of these barriers is insurmountable if appropriate action is taken.

  19. Mechanical energy input to the world oceans due to atmospheric loading

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; QIAN Chengchun; HUANG Ruixin

    2006-01-01

    Mechanical energy input to the oceans is one of the most important factors controlling the oceanic general circulation. The atmosphere transports mechanical energy to the oceans primarily through wind stress, plus changes of the sea level pressure (the so-called atmospheric loading). The rate of mechanical energy transfer into the ocean due to atmospheric loading is calculated, based on TOPEX/POSEIDON data over ten-year period (1993-2002). The rate of total energy input for the world oceans is estimated at 0.04TW (1TW=1012Watt), and most of this energy input is concentrated in the Southern Oceans and the Storm Tracks in the Northern Hemisphere. This energy input varied greatly with time, and the amplitude of the interannual variability over the past ten years is about 15%.

  20. Energy saving mechanisms, collective behavior and the variation range hypothesis in biological systems: A review

    CERN Document Server

    Trenchard, Hugh

    2016-01-01

    Energy saving mechanisms are ubiquitous in nature. Aerodynamic and hydrodynamic drafting, vortice uplift, Bernoulli suction, thermoregulatory coupling, path following, physical hooks, synchronization, and cooperation are only some of the better-known examples. While drafting mechanisms also appear in non-biological systems such as sedimentation and particle vortices, the broad spectrum of these mechanisms appears more diversely in biological systems including bacteria, spermatozoa, various aquatic species, birds, land animals, semi-fluid dwellers like turtle hatchlings, as well as human systems. We present the thermodynamic framework for energy saving mechanisms, and we review evidence in favor of the variation range hypothesis. This hypothesis posits that, as an evolutionary process, the variation range between strongest and weakest group members converges on the equivalent energy saving quantity that is generated by the energy saving mechanism. We also review self-organized structures that emerge due to ene...

  1. Overview of human obesity and central mechanisms regulating energy homeostasis.

    Science.gov (United States)

    Crowley, Vivion E F

    2008-05-01

    Obesity is now regarded as a global epidemic affecting both adults and children, and is associated with significant morbidity and mortality. Thus the effective management of obesity has become an important clinical focus. Therefore, an understanding of the pathways controlling appetite, satiety and food intake is critical for gaining an insight into the pathogenesis of obesity and also for the development of diagnostic tests and therapeutic agents for use in the clinical management of this condition. Over the last decade or more research using both mouse and human genetic models has elucidated the critical role of the leptin-melanocortin pathway in the hypothalamus, in regulating mammalian energy balance. In tandem with this, a clearer understanding of the regulation of gut-derived hormones and their interaction with the central nervous system has further illuminated the complex interplay between central and peripheral aspects of energy regulation. The obesity epidemic and the expanded knowledge base relating to its aetiopathogenesis have specific implications for clinical biochemistry. In particular, an increase in workload may be expected due to biochemical investigation of obesity and its co-morbidities. Moreover, advice on the in-depth investigation of complex cases of obesity may be sought, including information on newer diagnostic tests, such as serum leptin or molecular genetic analysis. There may also be a substantive role for chemical pathologists in establishing and running clinical obesity services. Finally, clinical biochemistry has a role in research pertaining to obesity and cardiometabolic risk.

  2. A mechanical energy harvested magnetorheological damper with linear-rotary motion converter

    Science.gov (United States)

    Chu, Ki Sum; Zou, Li; Liao, Wei-Hsin

    2016-04-01

    Magnetorheological (MR) dampers are promising to substitute traditional oil dampers because of adaptive properties of MR fluids. During vibration, significant energy is wasted due to the energy dissipation in the damper. Meanwhile, for conventional MR damping systems, extra power supply is needed. In this paper, a new energy harvester is designed in an MR damper that integrates controllable damping and energy harvesting functions into one device. The energy harvesting part of this MR damper has a unique mechanism converting linear motion to rotary motion that would be more stable and cost effective when compared to other mechanical transmissions. A Maxon motor is used as a power generator to convert the mechanical energy into electrical energy to supply power for the MR damping system. Compared to conventional approaches, there are several advantages in such an integrated device, including weight reduction, ease in installation with less maintenance. A mechanical energy harvested MR damper with linear-rotary motion converter and motion rectifier is designed, fabricated, and tested. Experimental studies on controllable damping force and harvested energy are performed with different transmissions. This energy harvesting MR damper would be suitable to vehicle suspensions, civil structures, and smart prostheses.

  3. Energy expenditure in the etiology of human obesity: spendthrift and thrifty metabolic phenotypes and energy-sensing mechanisms.

    Science.gov (United States)

    Piaggi, P; Vinales, K L; Basolo, A; Santini, F; Krakoff, J

    2017-07-24

    The pathogenesis of human obesity is the result of dysregulation of the reciprocal relationship between food intake and energy expenditure (EE), which influences daily energy balance and ultimately leads to weight gain. According to principles of energy homeostasis, a relatively lower EE in a setting of energy balance may lead to weight gain; however, results from different study groups are contradictory and indicate a complex interaction between EE and food intake which may differentially influence weight change in humans. Recently, studies evaluating the adaptive response of one component to perturbations of the other component of energy balance have revealed both the existence of differing metabolic phenotypes ("spendthrift" and "thrifty") resulting from overeating or underfeeding, as well as energy-sensing mechanisms linking EE to food intake, which might explain the propensity of an individual to weight gain. The purpose of this review is to debate the role that human EE plays on body weight regulation and to discuss the physiologic mechanisms linking EE and food intake. An increased understanding of the complex interplay between human metabolism and food consumption may provide insight into pathophysiologic mechanisms underlying weight gain, which may eventually lead to prevention and better treatment of human obesity.

  4. Biochemical Mechanisms and Energy Strategies of Geobacter Sulfurreducens

    Energy Technology Data Exchange (ETDEWEB)

    Tien, Ming; Brantley, Susan L.

    2013-10-28

    To provide the scientific understanding required to allow DOE sites to incorporate relevant biological, chemical, and physical processes into decisions concerning environmental remediation, a fundamental understanding of the controls on micro-organism growth in the subsurface is necessary. Specifically, mobility of metals in the environment, including chromium, technetium and uranium, is greatly affected by the process of dissimilatory metal reduction (DMR), which has been shown to be an important biological activity controlling contaminant mobility in the subsurface at many DOE sites. Long-term maintenance of DMR at constant rates must rely upon steady fluxes of electron donors to provide the maintenance energy needed by organisms such as Geobacter sulfurreducens to maintain steady state populations in the subsurface.

  5. Relativity in Classical Mechanics: Momentum, Energy and the Third Law

    CERN Document Server

    Assumpcao, R

    2005-01-01

    Most of the logical objections against the classical laws of motion, as they are usually presented in textbooks, centre on the fact that defining force in terms of mass and acceleration, the first two laws are mere assertions of concepts to be introduced in the theory; conversely, the third law expresses the experimental fact that the ratio of masses is inversely proportional to the ratio of accelerations, but it is known to fail when the interacting bodies are rapidly accelerated or far apart, leading to objections at the research level, particularly when electromagnetic phenomena is present. Following a specification of the coordinate system with respect to which velocities and accelerations are to be measured, relative to a fixed spacetime point, this contribution argues that the limitation of the third law is removed; as a consequence, Energy and Momentum relations are given an alternative formulation, extending their fundamental aspects and terms to the relativistic level. Most important, the presented a...

  6. Electrochemical and mechanical processes at surfaces and interfaces of advanced materials for energy storage

    Science.gov (United States)

    Shi, Feifei

    Energy storage is a rapidly emerging field. In almost all energy storage applications, surfaces and interfaces are playing dominant roles. Examples are fuel cell electrodes, where electro-catalytic reactions occur, Li-ion battery (LIB) electrodes, where electrolyte decomposition and passivation commence simultaneously, and failure (fracture) of battery electrodes, where surface crack initiation greatly affects battery endurance. The most fundamental chemical, electrochemical, and mechanical problems in energy storage applications originate from surfaces and interfaces. This thesis investigates the electrochemical and mechanical processes at surfaces and interfaces of advanced materials for energy applications. The thesis includes the following five main research topics. (Abstract shortened by ProQuest.).

  7. A comparison of the heat and mechanical energy of a heat-pump wind turbine system

    Energy Technology Data Exchange (ETDEWEB)

    Aybek, A.; Arslan, S.; Yildiz, E.; Atik, K. [University of Kahramanmaras (Turkey). Dept. of Agricultural Machinery

    2000-07-01

    While a variety of applications of wind energy have been studied in Turkey, no significant efforts have been made to utilize heat pumps for heat generation. The use of heat pumps in wind energy systems is worth considering because of the high efficiency of heat production. In this study, a directly coupled wind turbine-heat pump system was designed, constructed, and tested. Measurements determined the mechanical energy of the rotors of the wind turbine and the heat energy generated by the heat pump driven by the rotor shaft. Based on the comparisons between the power generated by the heat pump and the power of the Savonius rotors, it was found that the heat energy gained by the heat pump was four times greater than the mechanical energy obtained from the turbine. It was suggested that heat pumps could be efficiently used in wind energy systems. (Author)

  8. Converging ligand-binding free energies obtained with free-energy perturbations at the quantum mechanical level.

    Science.gov (United States)

    Olsson, Martin A; Söderhjelm, Pär; Ryde, Ulf

    2016-06-30

    In this article, the convergence of quantum mechanical (QM) free-energy simulations based on molecular dynamics simulations at the molecular mechanics (MM) level has been investigated. We have estimated relative free energies for the binding of nine cyclic carboxylate ligands to the octa-acid deep-cavity host, including the host, the ligand, and all water molecules within 4.5 Å of the ligand in the QM calculations (158-224 atoms). We use single-step exponential averaging (ssEA) and the non-Boltzmann Bennett acceptance ratio (NBB) methods to estimate QM/MM free energy with the semi-empirical PM6-DH2X method, both based on interaction energies. We show that ssEA with cumulant expansion gives a better convergence and uses half as many QM calculations as NBB, although the two methods give consistent results. With 720,000 QM calculations per transformation, QM/MM free-energy estimates with a precision of 1 kJ/mol can be obtained for all eight relative energies with ssEA, showing that this approach can be used to calculate converged QM/MM binding free energies for realistic systems and large QM partitions. © 2016 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.

  9. Structures, properties, and energy-storage mechanisms of the semi-lunar process cuticles in locusts.

    Science.gov (United States)

    Wan, Chao; Hao, Zhixiu; Feng, Xiqiao

    2016-10-17

    Locusts have excellent jumping and kicking abilities to survive in nature, which are achieved through the energy storage and release processes occurring in cuticles, especially in the semi-lunar processes (SLP) at the femorotibial joints. As yet, however, the strain energy-storage mechanisms of the SLP cuticles remain unclear. To decode this mystery, we investigated the microstructure, material composition, and mechanical properties of the SLP cuticle and its remarkable strain energy-storage mechanisms for jumping and kicking. It is found that the SLP cuticle of adult Locusta migratoria manilensis consists of five main parts that exhibit different microstructural features, material compositions, mechanical properties, and biological functions in storing strain energy. The mechanical properties of these five components are all transversely isotropic and strongly depend on their water contents. Finite element simulations indicate that the two parts of the core region of the SLP cuticle likely make significant contributions to its outstanding strain energy-storage ability. This work deepens our understanding of the locomotion behaviors and superior energy-storage mechanisms of insects such as locusts and is helpful for the design and fabrication of strain energy-storage devices.

  10. Structures, properties, and energy-storage mechanisms of the semi-lunar process cuticles in locusts

    Science.gov (United States)

    Wan, Chao; Hao, Zhixiu; Feng, Xiqiao

    2016-10-01

    Locusts have excellent jumping and kicking abilities to survive in nature, which are achieved through the energy storage and release processes occurring in cuticles, especially in the semi-lunar processes (SLP) at the femorotibial joints. As yet, however, the strain energy-storage mechanisms of the SLP cuticles remain unclear. To decode this mystery, we investigated the microstructure, material composition, and mechanical properties of the SLP cuticle and its remarkable strain energy-storage mechanisms for jumping and kicking. It is found that the SLP cuticle of adult Locusta migratoria manilensis consists of five main parts that exhibit different microstructural features, material compositions, mechanical properties, and biological functions in storing strain energy. The mechanical properties of these five components are all transversely isotropic and strongly depend on their water contents. Finite element simulations indicate that the two parts of the core region of the SLP cuticle likely make significant contributions to its outstanding strain energy-storage ability. This work deepens our understanding of the locomotion behaviors and superior energy-storage mechanisms of insects such as locusts and is helpful for the design and fabrication of strain energy-storage devices.

  11. Fluid Mechanics Explains Cosmology, Dark Matter, Dark Energy, and Life

    CERN Document Server

    Gibson, Carl H

    2012-01-01

    Observations of the interstellar medium by the Herschel, Planck etc. infrared satellites throw doubt on standard {\\Lambda}CDMHC cosmological processes to form gravitational structures. According to the Hydro-Gravitational-Dynamics (HGD) cosmology of Gibson (1996), and the quasar microlensing observations of Schild (1996), the dark matter of galaxies consists of Proto-Globular-star-Cluster (PGC) clumps of Earth-mass primordial gas planets in metastable equilibrium since PGCs began star production at 0.3 Myr by planet mergers. Dark energy and the accelerating expansion of the universe inferred from SuperNovae Ia are systematic dimming errors produced as frozen gas dark matter planets evaporate to form stars. Collisionless cold dark matter that clumps and hierarchically clusters does not exist. Clumps of PGCs began diffusion from the Milky Way Proto-Galaxy upon freezing at 14 Myr to give the Magellanic Clouds and the faint dwarf galaxies of the 10^22 m diameter baryonic dark matter Galaxy halo. The first stars p...

  12. Prostate radiation therapy: In vivo measurement of the dose delivered by kV-C.B.C.T; Radiotherapie des cancers de la prostate: evaluation in vivo de la dose delivree par tomographie conique de basse energie (kV)

    Energy Technology Data Exchange (ETDEWEB)

    Marinello, G.; Mege, J.P.; Besse, M.C.; Kerneur, G. [CHU Henri-Mondor, Unite de Radiophysique et de Radioprotection du Patient, 94 - Creteil (France); Lagrange, J.L. [CHU Henri-Mondor, Service de Radiotherapie, 94 - Creteil (France); Paris-12 Univ., 94 - Creteil (France)

    2009-09-15

    Purpose: To investigate if the regular use of kilo voltage cone beam computed tomography (kV-C.B.C.T.) notably increases the dose delivered to tumor and surrounding healthy tissues. Material and methods: Images were obtained using a Varian equipment (O.B.I. version 1.3, 645 to 650 projections in 370 degrees to acquire image), and patients were irradiated at source-tumor distance: 100 cm. In vivo measurements were performed using radio-thermoluminescent dosimeters Harshaw-TLD 700 H (TLD) at skin (anterior-posterior and lateral axis crossing the rotation axis), with a fourth TLD group under the table thanks to a retro-laser. TLD were calibrated at the kV-C.B.C.T. effective energy (64 keV), and the method validated using an anthropomorphic phantom, in which Gafchromic E.B.T. films were also inserted. Results: The phantom study showed that the dose distribution depends on the phantom position relative to the axis and that the doses measured at the phantom surface using TLD and films (good agreement) were maximum at the entrance of the anterior-posterior axis. Their arithmetic mean was equal, or a slightly greater than doses measured at mid-thickness of the phantom and at the level of the rectum (O.A.R., organ at risk). In vivo measurements performed on the five first patients (125 kV-C.B.C.T.) yield a mean skin dose per kV-C.B.C.T. varying from 5.8 {+-} 0.1 to 7.3 {+-} 0.2 c Gy on the anterior-posterior axis. Lateral skin doses vary from 3.4{+-}0.2 to 4.5 {+-} 0.2 c Gy. Conclusion: Doses delivered by repeated kV-C.B.C.T. are not negligible. They should be taken into account, but questions about the RBE to be applied to kilo voltage X-rays are raised. (authors)

  13. COMPARISON OF ENERGY AND EXERGY EFFICIENCIES OF ABSORPTION REFRIGERATION SYSTEM WITH MECHANICAL COMPRESSION REFRIGERATION SYSTEM

    OpenAIRE

    2005-01-01

    In this study, energy and exergy analysis of absorption refrigeration system using LiBr- water and mechanical compression refrigeration system using R134-a were performed at different evaporation temperatures. The results are presented in tables and figures.

  14. CONTROLLING AS A MECHANISM TO INCREASE THE EFFICIENCY OF MANAGEMENT ENTERPRISES OF FUEL-ENERGY COMPLEX

    Directory of Open Access Journals (Sweden)

    M. A. Ostashkin

    2013-01-01

    Full Text Available This article discusses the possibility of application of controlling as mechanism of increasing the efficiency of management of enterprises of fuel- energy complex. The research was conducted on the materials of the JSC «Gazprom».

  15. Financial mechanisms for renewable energy sources; Mecanismos financeiros para fontes de energia renovaveis

    Energy Technology Data Exchange (ETDEWEB)

    Moya Chaves, Francisco David [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2006-07-01

    This work presents three different financial mechanisms in the world as choices in the electricity generation investment from alternative energy sources. It shows a description of the following methods developed in the world: payment capacity, social costs of energy, and markets that trade renewable energies certificates. Finally, a recommendation about the best choice that could be implemented in Brazil is suggested. Given the importance in the use of the renewable energy of electric energy generation, most of the electric systems in the world have developed mechanisms to encourage the use of alternative energies. With the capacity payment the power plants that employ alternative sources, can receive extra payment as benefits for their initial investment. A possibility could be fixing taxes for the generation of electricity with fossil fuel that could finance the renewable energy sources. A renewable energy market dealing with trade able certificates, forces the electricity purchasers to have a percentage from alternative energies of the totally energy acquired. In this way the forced purchasing of energy from power plants which use energy certificates allows the expansion of these technologies. (author)

  16. Finite Element Analysis of Flat Spiral Spring on Mechanical Elastic Energy Storage Technology

    Directory of Open Access Journals (Sweden)

    Jingqiu Tang

    2014-02-01

    Full Text Available Energy storage technology has become an effective way of storing energy and improving power output controllability in modern power grid. The mechanical elastic energy storage technology on flat spiral spring is a new energy storage technology. This study states the mechanical elastic energy storage technology, models the mechanical model. Aimed to three kinds of structure and size of flat spiral spring, the finite element model are modeled, modal analysis is completed and the natural frequencies and the first 10-order vibration modes of the spring are analyzed, the relationship of natural frequency and vibration mode of spiral spring and structure and size is analyzed. The research results can provide the reference for the structure design and dynamics analysis.

  17. Nanowire Structured Hybrid Cell for Concurrently Scavenging Solar and Mechanical Energies

    KAUST Repository

    Xu, Chen

    2009-04-29

    Conversion cells for harvesting solar energy and mechanical energy are usually separate and independent entities that are designed and built following different physical principles. Developing a technology that harvests multiple-type energies in forms such as sun light and mechanical around the clock is desperately desired for fully utilizing the energies available in our living environment. We report a hybrid cell that is intended for simultaneously harvesting solar and mechanical energies. Using aligned ZnO nanowire arrays grown on surfaces of a flat substrate, a dye-sensitized solar cell is integrated with a piezoelectric nanogenerator. The former harvests solar energy irradiating on the top, and the latter harvests ultrasonic wave energy from the surrounding. The two energy harvesting approaches can work simultaneously or individually, and they can be integrated in parallel and serial for raising the output current and voltage, respectively, as well as power. It is found that the voltage output from the solar cell can be used to raise the output voltage of the nanogenerator, providing an effective approach for effectively storing and utilizing the power generated by the nanogenerator. Our study demonstrates a new approach for concurrently harvesting multiple types of energies using an integrated hybrid cell so that the energy resources can be effectively and complementary utilized whenever and wherever one or all of them is available. © 2009 American Chemical Society.

  18. Constraining sources of ultrahigh energy cosmic rays and shear acceleration mechanism of particles in relativistic jets

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ruoyu

    2015-06-10

    Ultrahigh energy cosmic rays are extreme energetic particles from outer space. They have aroused great interest among scientists for more than fifty years. However, due to the rarity of the events and complexity of the process of their propagation to Earth, they are still one of the biggest puzzles in modern high energy astrophysics. This dissertation is dedicated to study the origin of ultrahigh energy cosmic rays from various aspects. Firstly, we discuss a possible link between recently discovered sub-PeV/PeV neutrinos and ultrahigh energy cosmic rays. If these two kinds of particles share the same origin, the observation of neutrinos may provide additional and non-trivial constraints on the sources of ultrahigh energy cosmic rays. Secondly, we jointly employ the chemical composition measurement and the arrival directions of ultrahigh energy cosmic rays, and find a robust upper limit for distances of sources of ultrahigh energy cosmic rays above ∝55 EeV, as well as a lower limit for their metallicities. Finally, we study the shear acceleration mechanism in relativistic jets, which is a more efficient mechanism for the acceleration of higher energy particle. We compute the acceleration efficiency and the time-dependent particle energy spectrum, and explore the feature of synchrotron radiation of the accelerated particles. The possible realizations of this mechanism for acceleration of ultrahigh energy cosmic rays in different astrophysical environments is also discussed.

  19. Review of the inverse scattering problem at fixed energy in quantum mechanics

    Science.gov (United States)

    Sabatier, P. C.

    1972-01-01

    Methods of solution of the inverse scattering problem at fixed energy in quantum mechanics are presented. Scattering experiments of a beam of particles at a nonrelativisitic energy by a target made up of particles are analyzed. The Schroedinger equation is used to develop the quantum mechanical description of the system and one of several functions depending on the relative distance of the particles. The inverse problem is the construction of the potentials from experimental measurements.

  20. Patterns of Selection of Human Movements IV: Energy Efficiency, Mechanical Advantage, and Asynchronous Arm-Cranking

    OpenAIRE

    Hagler, Stuart

    2017-01-01

    Human movements are physical processes combining the classical mechanics of the human body moving in space and the biomechanics of the muscles generating the forces acting on the body under sophisticated sensory-motor control. The characterization of the performance of human movements is a problem with important applications in clinical and sports research. One way to characterize movement performance is through measures of energy efficiency that relate the mechanical energy of the body and m...

  1. An Estimation of Hybrid Quantum Mechanical Molecular Mechanical Polarization Energies for Small Molecules Using Polarizable Force-Field Approaches.

    Science.gov (United States)

    Huang, Jing; Mei, Ye; König, Gerhard; Simmonett, Andrew C; Pickard, Frank C; Wu, Qin; Wang, Lee-Ping; MacKerell, Alexander D; Brooks, Bernard R; Shao, Yihan

    2017-02-14

    In this work, we report two polarizable molecular mechanics (polMM) force field models for estimating the polarization energy in hybrid quantum mechanical molecular mechanical (QM/MM) calculations. These two models, named the potential of atomic charges (PAC) and potential of atomic dipoles (PAD), are formulated from the ab initio quantum mechanical (QM) response kernels for the prediction of the QM density response to an external molecular mechanical (MM) environment (as described by external point charges). The PAC model is similar to fluctuating charge (FQ) models because the energy depends on external electrostatic potential values at QM atomic sites; the PAD energy depends on external electrostatic field values at QM atomic sites, resembling induced dipole (ID) models. To demonstrate their uses, we apply the PAC and PAD models to 12 small molecules, which are solvated by TIP3P water. The PAC model reproduces the QM/MM polarization energy with a R(2) value of 0.71 for aniline (in 10,000 TIP3P water configurations) and 0.87 or higher for other 11 solute molecules, while the PAD model has a much better performance with R(2) values of 0.98 or higher. The PAC model reproduces reference QM/MM hydration free energies for 12 solute molecules with a RMSD of 0.59 kcal/mol. The PAD model is even more accurate, with a much smaller RMSD of 0.12 kcal/mol, with respect to the reference. This suggests that polarization effects, including both local charge distortion and intramolecular charge transfer, can be well captured by induced dipole type models with proper parametrization.

  2. Indoor Environmental Quality in Mechanically Ventilated, Energy-Efficient Buildings vs. Conventional Buildings.

    Science.gov (United States)

    Wallner, Peter; Munoz, Ute; Tappler, Peter; Wanka, Anna; Kundi, Michael; Shelton, Janie F; Hutter, Hans-Peter

    2015-11-06

    Energy-efficient buildings need mechanical ventilation. However, there are concerns that inadequate mechanical ventilation may lead to impaired indoor air quality. Using a semi-experimental field study, we investigated if exposure of occupants of two types of buildings (mechanical vs. natural ventilation) differs with regard to indoor air pollutants and climate factors. We investigated living and bedrooms in 123 buildings (62 highly energy-efficient and 61 conventional buildings) built in the years 2010 to 2012 in Austria (mainly Vienna and Lower Austria). Measurements of indoor parameters (climate, chemical pollutants and biological contaminants) were conducted twice. In total, more than 3000 measurements were performed. Almost all indoor air quality and room climate parameters showed significantly better results in mechanically ventilated homes compared to those relying on ventilation from open windows and/or doors. This study does not support the hypothesis that occupants in mechanically ventilated low energy houses are exposed to lower indoor air quality.

  3. Indoor Environmental Quality in Mechanically Ventilated, Energy-Efficient Buildings vs. Conventional Buildings

    Directory of Open Access Journals (Sweden)

    Peter Wallner

    2015-11-01

    Full Text Available Energy-efficient buildings need mechanical ventilation. However, there are concerns that inadequate mechanical ventilation may lead to impaired indoor air quality. Using a semi-experimental field study, we investigated if exposure of occupants of two types of buildings (mechanical vs. natural ventilation differs with regard to indoor air pollutants and climate factors. We investigated living and bedrooms in 123 buildings (62 highly energy-efficient and 61 conventional buildings built in the years 2010 to 2012 in Austria (mainly Vienna and Lower Austria. Measurements of indoor parameters (climate, chemical pollutants and biological contaminants were conducted twice. In total, more than 3000 measurements were performed. Almost all indoor air quality and room climate parameters showed significantly better results in mechanically ventilated homes compared to those relying on ventilation from open windows and/or doors. This study does not support the hypothesis that occupants in mechanically ventilated low energy houses are exposed to lower indoor air quality.

  4. Expanding Energy Performance Contracting in china: policy solutions and market mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Lynn [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Liu, Xu [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Meng, Lu [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shi, Wenjing [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Evans, Meredydd [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Roshchanka, Volha [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Yu, Sha [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-07-19

    Energy performance contracting is an important market mechanism that uses energy savings to pay over time for the upfront costs of energy efficiency retrofits in buildings, industries, and other types of facilities. Through energy performance contracts (EPCs), Energy Service Companies (ESCOs) play an important role in implementing energy efficiency retrofits. Both China and the United States have large markets for EPCs and significant opportunities for growth. The Chinese government has made great efforts in promoting the country’s ESCO business and expanding its EPC markets. This paper makes a series of recommendations for China to adopt more ambitious policy measures to encourage deep energy savings projects via EPCs. These recommendations are built on initial insights from a white paper developed by researchers at the Pacific Northwest National Laboratory and the Lawrence Berkeley National Laboratory with the assistance from the ESCO Committee of China’s Energy Conservation Association (EMCA). Key recommendations are listed below.

  5. Energy Conservation Behaviour Toolkit. Incentive Mechanisms for effective decrease of energy consumption at the workplace

    Energy Technology Data Exchange (ETDEWEB)

    Boerner, D.; Kalz, M.; Ternier, S.; Specht, M. [Centre for Learning Sciences and Technologies CELSTEC, Open Universiteit, Heerlen (Netherlands)

    2013-01-15

    The work in this project is based on a previous project (Energy Awareness Displays - Making the Invisible Visible) in which several measurement and visualization approaches have been developed to make employees more aware about energy consumption and pro-environmental behavior at the workplace. While awareness is a first important step for the decrease of energy consumption and environmental learning it is not sufficient as a means for sustainable behavior change. For this reason we have explored in the follow-up project approaches how pro-environmental behavior at the workplace can be encouraged, rewarded and sustained. For this purpose we have implemented several technological solutions and we have piloted these in form of an energy conservation game called Mindergie at the main campus of the Open University in Heerlen, Netherlands. The project is in line with an earlier identified research gap in terms of energy conservation at the workplace and uses state-of-the-art technologies for mobile gaming and rewarding of non-formal learning activities.

  6. A Comparison of Kinetic Energy and Momentum in Special Relativity and Classical Mechanics

    Science.gov (United States)

    Riggs, Peter J.

    2016-01-01

    Kinetic energy and momentum are indispensable dynamical quantities in both the special theory of relativity and in classical mechanics. Although momentum and kinetic energy are central to understanding dynamics, the differences between their relativistic and classical notions have not always received adequate treatment in undergraduate teaching.…

  7. A Comparison of Kinetic Energy and Momentum in Special Relativity and Classical Mechanics

    Science.gov (United States)

    Riggs, Peter J.

    2016-01-01

    Kinetic energy and momentum are indispensable dynamical quantities in both the special theory of relativity and in classical mechanics. Although momentum and kinetic energy are central to understanding dynamics, the differences between their relativistic and classical notions have not always received adequate treatment in undergraduate teaching.…

  8. How to Transform Mechanical Work into Electrical Energy Using a Capacitor

    Science.gov (United States)

    Skumiel, A.

    2011-01-01

    In this paper the method of converting mechanical work into electrical energy with the participation of a preliminarily charged condenser while the electrodes are sliding in it is presented. Using this method, we can obtain a considerable increase of converted electrical power, depending on the initial energy of the charged condenser, distance…

  9. An energy saving mechanism of EPON networks for real time video transmission

    Science.gov (United States)

    Liu, Chien-Ping; Wu, Ho-Ting; Chiang, Yun-Ting; Chien, Shieh-Chieh; Ke, Kai-Wei

    2015-07-01

    Modern access networks are constructed widely by passive optical networks (PONs) to meet the growing bandwidth demand. However, higher bandwidth means more energy consumption. To save energy, a few research works propose the dual-mode energy saving mechanism that allows the ONU to operate between active and sleep modes periodically. However, such dual-mode energy saving design may induce unnecessary power consumption or packet delay increase in the case where only downstream data exist for most of the time. In this paper, we propose a new tri-mode energy saving scheme for Ethernet PON (EPON). The new tri-mode energy saving design, combining the dual-mode saving mechanism with the doze mode, allows the ONU to switch among these three modes alternatively. In the doze mode, the ONU may receive downstream data while keeping its transmitter close. Such scenario is often observed for real time video downstream transmission. Furthermore, the low packet delay of high priority upstream data can be attained through the use of early wake-up mechanism employed in both energy saving modes. The energy saving and system efficiency can thus be achieved jointly while maintaining the differentiated QoS for data with various priorities. Performance results via simulation have demonstrated the effectiveness of such mechanism.

  10. Effects of symmetry energy and momentum dependent interaction on low-energy reaction mechanisms

    CERN Document Server

    Zheng, H; Baran, V; Burrello, S

    2015-01-01

    We study the dipole response associated with the Pygmy Dipole Resonance (PDR) and the Isovector Giant Dipole Resonance (IVGDR), in connection with specific properties of the nuclear effective interaction (symmetry energy and momentum dependence), in the neutron-rich systems $^{68}$Ni, $^{132}$Sn and $^{208}$Pb. We perform our investigation within a microscopic transport model based on the Landau-Vlasov kinetic equation. We observe that the peak energies of PDR and IVGDR are shifted to higher values when employing momentum dependent interactions, with respect to the results obtained neglecting momentum dependence. The calculated energies are close to the experimental values and similar to the results obtained in Hartree-Fock (HF) with Random Phase Approximation (RPA) calculations.

  11. Effects of symmetry energy and momentum dependent interaction on low-energy reaction mechanisms

    Directory of Open Access Journals (Sweden)

    Zheng H.

    2016-01-01

    Full Text Available We study the dipole response associated with the Pygmy Dipole Resonance (PDR and the Isovector Giant Dipole Resonance (IVGDR, in connection with specific properties of the nuclear effective interaction (symmetry energy and momentum dependence, in the neutron-rich systems 68Ni, 132Sn and 208Pb. We perform our investigation within a microscopic transport model based on the Landau-Vlasov kinetic equation.We observe that the peak energies of PDR and IVGDR are shifted to higher values when employing momentum dependent interactions, with respect to the results obtained neglecting momentum dependence. The calculated energies are close to the experimental values and similar to the results obtained in Hartree-Fock (HF with Random Phase Approximation (RPA calculations.

  12. A Model for Sustainable Building Energy Efficiency Retrofit (BEER) Using Energy Performance Contracting (EPC) Mechanism for Hotel Buildings in China

    Science.gov (United States)

    Xu, Pengpeng

    Hotel building is one of the high-energy-consuming building types, and retrofitting hotel buildings is an untapped solution to help cut carbon emissions contributing towards sustainable development. Energy Performance Contracting (EPC) has been promulgated as a market mechanism for the delivery of energy efficiency projects. EPC mechanism has been introduced into China relatively recently, and it has not been implemented successfully in building energy efficiency retrofit projects. The aim of this research is to develop a model for achieving the sustainability of Building Energy Efficiency Retrofit (BEER) in hotel buildings under the Energy Performance Contracting (EPC) mechanism. The objectives include: • To identify a set of Key Performance Indicators (KPIs) for measuring the sustainability of BEER in hotel buildings; • To identify Critical Success Factors (CSFs) under EPC mechanism that have a strong correlation with sustainable BEER project; • To develop a model explaining the relationships between the CSFs and the sustainability performance of BEER in hotel building. Literature reviews revealed the essence of sustainable BEER and EPC, which help to develop a conceptual framework for analyzing sustainable BEER under EPC mechanism in hotel buildings. 11 potential KPIs for sustainable BEER and 28 success factors of EPC were selected based on the developed framework. A questionnaire survey was conducted to ascertain the importance of selected performance indicators and success factors. Fuzzy set theory was adopted in identifying the KPIs. Six KPIs were identified from the 11 selected performance indicators. Through a questionnaire survey, out of the 28 success factors, 21 Critical Success Factors (CSFs) were also indentified. Using the factor analysis technique, the 21 identified CSFs in this study were grouped into six clusters to help explain project success of sustainable BEER. Finally, AHP/ANP approach was used in this research to develop a model to

  13. Walking at non-constant speeds: mechanical work, pendular transduction, and energy congruity.

    Science.gov (United States)

    Balbinot, G

    2017-05-01

    Although almost half of all walking bouts in urban environments consist of less than 12 consecutive steps and several day-to-day gait activities contain transient gait responses, in most studies gait analysis is performed at steady-state. This study aimed to analyze external (Wext ) and internal mechanical work (Wint ), pendulum-like mechanics, and elastic energy usage during constant and non-constant speeds. The mechanical work, pendular transduction, and energy congruity (an estimate of storage and release of elastic energy) during walking were computed using two force platforms. We found that during accelerating gait (+NCS) energy recovery is maintained, besides extra W(+)ext , for decelerating gait (-NCS) poor energy recovery was counterbalanced by W(-)ext and C% predominance. We report an increase in elastic energy usage with speed (4-11%). Both W(-)ext and %C suggests that elastic energy usage is higher at faster speeds and related to -NCS (≈20% of elastic energy usage). This study was the first to show evidences of elastic energy usage during constant and non-constant speeds.

  14. A SIEPON based transmitter sleep mode energy-efficient mechanism in EPON

    Science.gov (United States)

    Nikoukar, AliAkbar; Hwang, I.-Shyan; Wang, Chien-Jung; Ab-Rahman, Mohammad Syuhaimi; Liem, Andrew Tanny

    2015-06-01

    The main energy consumption in computer networks is the access networks. The passive optical network (PON) has the least energy consumption among access network technologies. In addition, the time division multiplexing (TDM) Ethernet PON (EPON) is one of the best candidates to improve energy consumption by time utilization. The optical network unit (ONU) can utilize the time and save the energy in the EPON by turning off its transmitter/receiver when there is no upstream/downstream traffic. The ITU-T and IEEE organizations are published standards for energy-saving in the TDM-PON. Although their standards provide the framework to accomplish the energy-saving, the algorithms/criteria to generate events to accommodate various operational policies, time to wake up, parameter values for timers are out of scope of the standards. Many studies have proposed schemes for energy-saving in TDM-PON to achieve maximum energy saving. Even so, these schemes increase the mean packet delay and consequently, reduce the quality of service (QoS). In this paper, first we take a look to the state of the art for PON energy-saving. Additionally, a mechanism based on SIEPON standard in EPON with new components in the ONUs and optical line terminal (OLT) is proposed to save the transmitter energy and guarantee QoS. The proposed mechanism follows the SIEPON standard, considers the QoS first, and then saves the energy as far as possible. The ONU sleep controller unit (OSC) and green dynamic bandwidth allocation (GDBA) are used to calculate the ONU transmitter sleep (Tx) duration and grant the proper time to the ONUs. Simulation results show that the proposed energy-saving mechanism not only promises the QoS performance in terms of mean packet delay, packet loss, throughput, and jitter, but also saves energy in different maximum cycle times.

  15. Light-Matter Interaction: Conversion of Optical Energy and Momentum to Mechanical Vibrations and Phonons

    CERN Document Server

    Mansuripur, Masud

    2016-01-01

    Reflection, refraction, and absorption of light by material media are, in general, accompanied by a transfer of optical energy and momentum to the media. Consequently, the eigen-modes of mechanical vibration (phonons) created in the process must distribute the acquired energy and momentum throughout the material medium. However, unlike photons, phonons do not carry momentum. What happens to the material medium in its interactions with light, therefore, requires careful consideration if the conservation laws are to be upheld. The present paper addresses some of the mechanisms by which the electromagnetic momentum of light is carried away by mechanical vibrations.

  16. Resonant electronic excitation energy transfer by Dexter mechanism in the quantum dot system

    Science.gov (United States)

    Samosvat, D. M.; Chikalova-Luzina, O. P.; Vyatkin, V. M.; Zegrya, G. G.

    2016-11-01

    In present work the energy transfer between quantum dots by the exchange (Dexter) mechanism is analysed. The interdot Coulomb interaction is taken into consideration. It is assumed that the quantum dot-donor and the quantum dot-acceptor are made from the same compound A3B5 and embedded in the matrix of other material creating potential barriers for electron and holes. The dependences of the energy transfer rate on the quantum-dot system parameters are found using the Kane model that provides the most adequate description spectra of semiconductors A3B5. Numerical calculations show that the rate of the energy transfer by Dexter mechanism is comparable to the rate of the energy transfer by electrostatic mechanism at the distances approaching to the contact ones.

  17. EBDC: An Energy-Balanced Data Collection Mechanism Using a Mobile Data Collector in WSNs

    Directory of Open Access Journals (Sweden)

    Chin-Hwa Kuo

    2012-05-01

    Full Text Available The data collection problem is one of the most important issues in Wireless Sensor Networks (WSNs. Constructing a tree from all sensor nodes to the sink node is the simplest way, but this raises the problem of energy unbalance since the sensors closer to the sink node would have much higher workloads from relaying data. To cope with the energy unbalance problem, a number of mobile-sink mechanisms have been proposed in recent years. This paper proposes an Energy-Balanced Data Collection mechanism, called EBDC, which determines the trajectory of a mobile data collector (or mobile sink such that the data-relaying workloads of all sensors can be totally balanced. Theoretical analysis and performance evaluation reveal that the proposed EBDC mechanism outperforms the existing approaches in terms of network lifetime and the degree of energy balancing.

  18. Mechanical energy assessment of adult with Down syndrome during walking with obstacle avoidance.

    Science.gov (United States)

    Salami, Firooz; Vimercati, Sara Laura; Rigoldi, Chiara; Taebi, Amirtaha; Albertini, Giorgio; Galli, Manuela

    2014-08-01

    The aim of this study is analyzing the differences between plane walking and stepping over an obstacle for two groups of healthy people and people with Down syndrome and then, evaluating the movement efficiency between the groups by comprising of their mechanical energy exchanges. 39 adults including two groups of 21 people with Down syndrome (age: 21.6 ± 7 years) and 18 healthy people (age: 25.1 ± 2.4 years) participated in this research. The test has been done in two conditions, first in plane walking and second in walking with an obstacle (10% of the subject's height). The gait data were acquired using quantitative movement analysis, composed of an optoelectronic system (Elite2002, BTS) with eight infrared cameras. Mechanical energy exchanges are computed by dedicated software and finally the data including spatiotemporal parameters, mechanical energy parameters and energy recovery of gait cycle are analyzed by statistical software to find significant differences. Regards to spatiotemporal parameters velocity and step length are lower in people with Down syndrome. Mechanical energy parameters particularly energy recovery does not change from healthy people to people with Down syndrome. However, there are some differences in inter-group through plane walking to obstacle avoidance and it means people with Down syndrome probably use their residual abilities in the most efficient way to achieve the main goal of an efficient energy recovery.

  19. Mechanisms of mitochondrial response to variations in energy demand in eukaryotic cells.

    Science.gov (United States)

    Devin, Anne; Rigoulet, Michel

    2007-01-01

    This review focuses on the different mechanisms involved in the adjustment of mitochondrial ATP production to cellular energy demand. The oxidative phosphorylation steady state at constant mitochondrial enzyme content can vary in response to energy demand. However, such an adaptation is tightly linked to a modification in both oxidative phosphorylation yield and phosphate potential and is obviously very limited in eukaryotic cells. We describe the three main mechanisms involved in mitochondrial response to energy demand. In heart cells, a short-term adjustment can be reached mainly through metabolic signaling via phosphotransfer networks by the compartmentalized energy transfer and signal transmission. In such a complex regulatory mechanism, Ca(2+) signaling participates in activation of matricial dehydrogenases as well as mitochondrial ATP synthase. These processes allow a large increase in ATP production rate without an important modification in thermodynamic forces. For a long-term adaptation, two main mechanisms are involved: modulation of the mitochondrial enzyme content as a function of energy demand and/or kinetic regulation by covalent modifications (phosphorylations) of some respiratory chain complex subunits. Regardless of the mechanism involved (kinetic regulation by covalent modification or adjustment of mitochondrial enzyme content), the cAMP signaling pathway plays a major role in molecular signaling, leading to the mitochondrial response. We discuss the energetic advantages of these mechanisms.

  20. Energy saving mechanisms, collective behavior and the variation range hypothesis in biological systems: A review.

    Science.gov (United States)

    Trenchard, Hugh; Perc, Matjaž

    2016-09-01

    Energy saving mechanisms are ubiquitous in nature. Aerodynamic and hydrodynamic drafting, vortice uplift, Bernoulli suction, thermoregulatory coupling, path following, physical hooks, synchronization, and cooperation are only some of the better-known examples. While drafting mechanisms also appear in non-biological systems such as sedimentation and particle vortices, the broad spectrum of these mechanisms appears more diversely in biological systems that include bacteria, spermatozoa, various aquatic species, birds, land animals, semi-fluid dwellers like turtle hatchlings, as well as human systems. We present the thermodynamic framework for energy saving mechanisms, and we review evidence in favor of the variation range hypothesis. This hypothesis posits that, as an evolutionary process, the variation range between strongest and weakest group members converges on the equivalent energy saving quantity that is generated by the energy saving mechanism. We also review self-organized structures that emerge due to energy saving mechanisms, including convective processes that can be observed in many systems over both short and long time scales, as well as high collective output processes in which a form of collective position locking occurs.

  1. Using quantum mechanics to improve estimates of amino acid side chain rotamer energies.

    Science.gov (United States)

    Renfrew, P Douglas; Butterfoss, Glenn L; Kuhlman, Brian

    2008-06-01

    Amino acid side chains adopt a discrete set of favorable conformations typically referred to as rotamers. The relative energies of rotamers partially determine which side chain conformations are more often observed in protein structures and accurate estimates of these energies are important for predicting protein structure and designing new proteins. Protein modelers typically calculate side chain rotamer energies by using molecular mechanics (MM) potentials or by converting rotamer probabilities from the protein database (PDB) into relative free energies. One limitation of the knowledge-based energies is that rotamer preferences observed in the PDB can reflect internal side chain energies as well as longer-range interactions with the rest of the protein. Here, we test an alternative approach for calculating rotamer energies. We use three different quantum mechanics (QM) methods (second order Møller-Plesset (MP2), density functional theory (DFT) energy calculation using the B3LYP functional, and Hartree-Fock) to calculate the energy of amino acid rotamers in a dipeptide model system, and then use these pre-calculated values in side chain placement simulations. Energies were calculated for over 36,000 different conformations of leucine, isoleucine, and valine dipeptides with backbone torsion angles from the helical and strand regions of the Ramachandran plot. In a subset of cases these energies differ significantly from those calculated with standard molecular mechanics potentials or those derived from PDB statistics. We find that in these cases the energies from the QM methods result in more accurate placement of amino acid side chains in structure prediction tests.

  2. The Role of Shearing Energy and Interfacial Gibbs Free Energy in the Emulsification Mechanism of Waxy Crude Oil

    Directory of Open Access Journals (Sweden)

    Zhihua Wang

    2017-05-01

    Full Text Available Crude oil is generally produced with water, and the water cut produced by oil wells is increasingly common over their lifetime, so it is inevitable to create emulsions during oil production. However, the formation of emulsions presents a costly problem in surface process particularly, both in terms of transportation energy consumption and separation efficiency. To deal with the production and operational problems which are related to crude oil emulsions, especially to ensure the separation and transportation of crude oil-water systems, it is necessary to better understand the emulsification mechanism of crude oil under different conditions from the aspects of bulk and interfacial properties. The concept of shearing energy was introduced in this study to reveal the driving force for emulsification. The relationship between shearing stress in the flow field and interfacial tension (IFT was established, and the correlation between shearing energy and interfacial Gibbs free energy was developed. The potential of the developed correlation model was validated using the experimental and field data on emulsification behavior. It was also shown how droplet deformation could be predicted from a random deformation degree and orientation angle. The results indicated that shearing energy as the energy produced by shearing stress working in the flow field is the driving force activating the emulsification behavior. The deformation degree and orientation angle of dispersed phase droplet are associated with the interfacial properties, rheological properties and the experienced turbulence degree. The correlation between shearing stress and IFT can be quantified if droplet deformation degree vs. droplet orientation angle data is available. When the water cut is close to the inversion point of waxy crude oil emulsion, the interfacial Gibbs free energy change decreased and the shearing energy increased. This feature is also presented in the special regions where

  3. Photophysical properties and energy transfer mechanism of PFO/Fluorol 7GA hybrid thin films

    Energy Technology Data Exchange (ETDEWEB)

    Al-Asbahi, Bandar Ali, E-mail: alasbahibandar@gmail.com [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Department of Physics, Faculty of Science, Sana' a University (Yemen); Jumali, Mohammad Hafizuddin Haji, E-mail: hafizhj@ukm.my [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Yap, Chi Chin; Flaifel, Moayad Husein [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Salleh, Muhamad Mat [Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

    2013-10-15

    Photophysical properties of poly (9,9′-di-n-octylfluorenyl-2.7-diyl) (PFO)/2-butyl-6- (butylamino)benzo [de] isoquinoline-1,3-dione (Fluorol 7GA) and energy transfer between them have been investigated. In this work, both PFO and Fluorol 7GA act as donor and acceptor, respectively. Based on the absorption and luminescence measurements, the photophysical and energy transfer properties such as fluorescence quantum yield (Φ{sub f}), fluorescence lifetime (τ), radiative rate constant (k{sub r}), non-radiative rate constant (k{sub nr}), quenching rate constant (k{sub SV}), energy transfer rate constant (k{sub ET}), energy transfer probability (P{sub DA}), energy transfer efficiency (η), critical concentration of acceptor (C{sub o}), energy transfer time (τ{sub ET}) and critical distance of energy transfer (R{sub o}) were calculated. Large values of k{sub SV}, k{sub ET} and R{sub o} suggested that Förster-type energy transfer was the dominant mechanism for the energy transfer between the excited donor and ground state acceptor molecules. It was observed that the Förster energy transfer together with the trapping process are crucial for performance improvement in ITO/(PFO/Fluorol7GA)/Al device. -- Highlights: • The efficient of energy transfer from PFO to Fluorol 7GA was evidenced. • The resonance energy transfer (Förster type) is the dominant mechanism. • Hsu et al. model was used to calculate Φ{sub f}, τ, k{sub r} and k{sub nr} of PFO thin film. • Several of the photophysical and energy transfer properties were calculated. • Trapping process and Förster energy transfer led to improve the device performance.

  4. Renewable energy support mechanisms in the Gulf Cooperation Council states: Analyzing the feasibility of feed-in tariffs and auction mechanisms

    NARCIS (Netherlands)

    Atalay, Yasemin; Kalfagianni, A.; Pattberg, Philipp

    2017-01-01

    Renewable energy will be a crucial ingredient in the transition to a more sustainable future. The renewable energy sector requires a variety of financial support mechanisms in order to further consolidate and expand. Currently, the most prominent renewable energy support mechanisms are feed-in

  5. Renewable energy support mechanisms in the Gulf Cooperation Council states: Analyzing the feasibility of feed-in tariffs and auction mechanisms

    NARCIS (Netherlands)

    Atalay, Yasemin; Kalfagianni, A.; Pattberg, Philipp

    2017-01-01

    Renewable energy will be a crucial ingredient in the transition to a more sustainable future. The renewable energy sector requires a variety of financial support mechanisms in order to further consolidate and expand. Currently, the most prominent renewable energy support mechanisms are feed-in tarif

  6. On the use of energy loss mechanisms to constrain Lorentz invariance violations

    CERN Document Server

    Mazón, Diego

    2014-01-01

    In light of recent and probably incoming observations of very high energy astroparticles, such as those reported by the IceCube collaboration, we readdress the energy loss mechanism by Lorentz violating particles. We analytically show that Cohen-Glashow's formula for energy loss is connected with a Poisson distribution for the number of decays, whose large fluctuations prevent from placing bounds on Lorentz invariance violations. However, this model ignores the sharp change in the decay width after each process. We propose replacing Poisson statistics with a new distribution that takes this into account. We study the average final energy and its fluctuations according to the new statistics, contrasting it with Cohen-Glashow's result and discussing the reliability of energy loss mechanisms to constrain violations of Lorentz invariance.

  7. Flying at no mechanical energy cost: disclosing the secret of wandering albatrosses.

    Directory of Open Access Journals (Sweden)

    Gottfried Sachs

    Full Text Available Albatrosses do something that no other birds are able to do: fly thousands of kilometres at no mechanical cost. This is possible because they use dynamic soaring, a flight mode that enables them to gain the energy required for flying from wind. Until now, the physical mechanisms of the energy gain in terms of the energy transfer from the wind to the bird were mostly unknown. Here we show that the energy gain is achieved by a dynamic flight manoeuvre consisting of a continually repeated up-down curve with optimal adjustment to the wind. We determined the energy obtained from the wind by analysing the measured trajectories of free flying birds using a new GPS-signal tracking method yielding a high precision. Our results reveal an evolutionary adaptation to an extreme environment, and may support recent biologically inspired research on robotic aircraft that might utilize albatrosses' flight technique for engineless propulsion.

  8. Flying at no mechanical energy cost: disclosing the secret of wandering albatrosses.

    Science.gov (United States)

    Sachs, Gottfried; Traugott, Johannes; Nesterova, Anna P; Dell'Omo, Giacomo; Kümmeth, Franz; Heidrich, Wolfgang; Vyssotski, Alexei L; Bonadonna, Francesco

    2012-01-01

    Albatrosses do something that no other birds are able to do: fly thousands of kilometres at no mechanical cost. This is possible because they use dynamic soaring, a flight mode that enables them to gain the energy required for flying from wind. Until now, the physical mechanisms of the energy gain in terms of the energy transfer from the wind to the bird were mostly unknown. Here we show that the energy gain is achieved by a dynamic flight manoeuvre consisting of a continually repeated up-down curve with optimal adjustment to the wind. We determined the energy obtained from the wind by analysing the measured trajectories of free flying birds using a new GPS-signal tracking method yielding a high precision. Our results reveal an evolutionary adaptation to an extreme environment, and may support recent biologically inspired research on robotic aircraft that might utilize albatrosses' flight technique for engineless propulsion.

  9. Energy cost and mechanical efficiency of riding a human-powered recumbent bicycle.

    Science.gov (United States)

    Capelli, Carlo; Ardigo, Luca Paolo; Schena, Federico; Zamparo, Paola

    2008-10-01

    When dealing with human-powered vehicles, it is important to quantify the capability of converting metabolic energy in useful mechanical work by measuring mechanical efficiency. In this study, net mechanical efficiency (eta) of riding a recumbent bicycle on flat terrain and at constant speeds (v, 5.1-10.0 m/s) was calculated dividing mechanical work (w, J/m) by the corresponding energy cost (C(c), J/m). w and C(c) increased linearly with the speed squared: w = 9.41 + 0.156 . v(2); C(c) = 39.40 + 0.563 . v(2). eta was equal to 0.257 +/- 0.0245, i.e. identical to that of concentric muscular contraction. Hence, i) eta seems unaffected by the biomechanical arrangement of the human-vehicle system; ii) the efficiency of transmission seems to be close to 100%, suggesting that the particular biomechanical arrangement does not impair the transformation of metabolic energy in mechanical work. When dealing with human-powered vehicles, it is important to quantify mechanical efficiency (eta) of locomotion. eta of riding a recumbent bicycle was calculated dividing the mechanical work to the corresponding energy cost of locomotion; it was practically identical to that of concentric muscular contraction (0.257 +/- 0.0245), suggesting that the power transmission from muscles to pedals is unaffected by the biomechanical arrangement of the vehicle.

  10. Quantum Mechanics/Molecular Mechanics Free Energy Maps and Nonadiabatic Simulations for a Photochemical Reaction in DNA: Cyclobutane Thymine Dimer.

    Science.gov (United States)

    Mendieta-Moreno, Jesús I; Trabada, Daniel G; Mendieta, Jesús; Lewis, James P; Gómez-Puertas, Paulino; Ortega, José

    2016-11-03

    The absorption of ultraviolet radiation by DNA may result in harmful genetic lesions that affect DNA replication and transcription, ultimately causing mutations, cancer, and/or cell death. We analyze the most abundant photochemical reaction in DNA, the cyclobutane thymine dimer, using hybrid quantum mechanics/molecular mechanics (QM/MM) techniques and QM/MM nonadiabatic molecular dynamics. We find that, due to its double helix structure, DNA presents a free energy barrier between nonreactive and reactive conformations leading to the photolesion. Moreover, our nonadiabatic simulations show that most of the photoexcited reactive conformations return to standard B-DNA conformations after an ultrafast nonradiative decay to the ground state. This work highlights the importance of dynamical effects (free energy, excited-state dynamics) for the study of photochemical reactions in biological systems.

  11. Experimental Study of a Small Scale Hydraulic System for Mechanical Wind Energy Conversion into Heat

    Directory of Open Access Journals (Sweden)

    Tadas Zdankus

    2016-07-01

    Full Text Available Significant potential for reducing thermal energy consumption in buildings of moderate and cold climate countries lies within wind energy utilisation. Unlike solar irradiation, character of wind speeds in Central and Northern Europe correspond to the actual thermal energy demand in buildings. However, mechanical wind energy undergoes transformation into electrical energy before being actually used as thermal energy in most wind energy applications. The study presented in this paper deals with hydraulic systems, designed for small-scale applications to eliminate the intermediate energy transformation as it converts mechanical wind energy into heat directly. The prototype unit containing a pump, flow control valve, oil tank and piping was developed and tested under laboratory conditions. Results of the experiments showed that the prototype system is highly efficient and adjustable to a broad wind velocity range by modifying the definite hydraulic system resistance. Development of such small-scale replicable units has the potential to promote “bottom-up” solutions for the transition to a zero carbon society.

  12. Mechanism of energy limit equilibrium of rock burst in coal mine

    Institute of Scientific and Technical Information of China (English)

    Wang Jiong; Yan Yubiao; Jiang Zhengjun; Qi Ping; Chen Chen

    2011-01-01

    With the increase of mining depth, the effect of rock burst on coal mining is becoming more and more obvious and the rock burst mechanism becomes more and more complicated. Scholars from many countries had put forward different mechanisms, but no one gave a reasonable explanation to the mechanism of rock burst. In this paper, based on the energy theories, we studied the energy limit equilibrium (ELE) of coal mine rock burst. The coal seam with rock burst is divided into energy limit equilibrium zone (ELEZ) (A) and elastic zone (B); we also determined the position where the rock burst occurs, including the roof and floor of coal seams; in addition, we derived the limit width of ELEZ and the mathematic relationship between the limit width and occurrence mechanism of rock burst: the energy difference function (EDF), w(x) = wJ - wp because first-order derivative w'(x), is less than 0. So EDF is a monotonically decreasing function. The graph of the energy difference function was also determined,through which we analysed the occurrence mechanism of rock burst.

  13. Effect of mechanical denaturation on surface free energy of protein powders.

    Science.gov (United States)

    Mohammad, Mohammad Amin; Grimsey, Ian M; Forbes, Robert T; Blagbrough, Ian S; Conway, Barbara R

    2016-10-01

    Globular proteins are important both as therapeutic agents and excipients. However, their fragile native conformations can be denatured during pharmaceutical processing, which leads to modification of the surface energy of their powders and hence their performance. Lyophilized powders of hen egg-white lysozyme and β-galactosidase from Aspergillus oryzae were used as models to study the effects of mechanical denaturation on the surface energies of basic and acidic protein powders, respectively. Their mechanical denaturation upon milling was confirmed by the absence of their thermal unfolding transition phases and by the changes in their secondary and tertiary structures. Inverse gas chromatography detected differences between both unprocessed protein powders and the changes induced by their mechanical denaturation. The surfaces of the acidic and basic protein powders were relatively basic, however the surface acidity of β-galactosidase was higher than that of lysozyme. Also, the surface of β-galactosidase powder had a higher dispersive energy compared to lysozyme. The mechanical denaturation decreased the dispersive energy and the basicity of the surfaces of both protein powders. The amino acid composition and molecular conformation of the proteins explained the surface energy data measured by inverse gas chromatography. The biological activity of mechanically denatured protein powders can either be reversible (lysozyme) or irreversible (β-galactosidase) upon hydration. Our surface data can be exploited to understand and predict the performance of protein powders within pharmaceutical dosage forms. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Optimal energy options under Clean Development Mechanism: Renewable energy projects for sustainable development and carbon emission reduction

    Science.gov (United States)

    Gilau, Asmerom M.

    This dissertation addresses two distinct objectives; designing cost-effective renewable energy powered projects including seawater reverse osmosis (SWRO), aquaculture, and ice-making plant, and analyzing the cost-effectiveness of these projects in achieving low abatement costs and promoting sustainable developments under the Clean Development Mechanism. The results of SWRO analysis show that a wind powered system is the least expensive and a PV powered system the most expensive, with finished water costs of about 0.50 /m3 and 1.00 /m3, respectively. By international standards, these costs are competitive. The results of renewable energy powered commercial tilapia production indicate that a wind-diesel system has high potential for intensive tilapia production as well as carbon dioxide emission reductions. The study also investigates aeration failures in renewable energy powered tilapia production systems. With respect to the ice-making plant, unlike previous studies which consider nighttime operation only, we have found that a nighttime PV powered ice-making system is more expensive (1/kWh) than daytime ice-making system (0.70/kWh). Our optimal energy options analysis at project scale which includes SWRO, ice-making plant and household energy consumption for about 100 households shows that compared to diesel only energy option, PV-D, W-D, and PV-W-D hybrids are very cost-effective energy options. Moreover, energy options with high levels of renewable energy including 100% renewables have the lowest net present cost and they are already cost-effective without CDM. On the other hand, while the removal of about 87% carbon dioxide emissions could be achieved at negative cost, initial investment could increase by a factor of 40, which is one of the primary barriers hindering wider renewable energy applications in developing countries. Thus in order to increase developing countries' participation in the carbon market, CDM policy should shift from a purely market oriented

  15. Biomass use in chemical and mechanical pulping with biomass-based energy supply

    Energy Technology Data Exchange (ETDEWEB)

    Holmberg, Jonas M.; Gustavsson, Leif [Department of Engineering Physics and Mathematics, Mid Sweden University, SE-831 25 Oestersund (Sweden)

    2007-12-15

    The pulp and paper industry is energy intensive and consumes large amounts of wood. Biomass is a limited resource and its efficient use is therefore important. In this study, the total amount of biomass used for pulp and for energy is estimated for the production of several woodfree (containing only chemical pulp) and mechanical (containing mechanical pulp) printing paper products, under Swedish conditions. Chemical pulp mills today are largely self-sufficient in energy while mechanical pulp mills depend on large amounts of external electricity. Technically, all energy used in pulp- and papermaking can be biomass based. Here, we assume that all energy used, including external electricity and motor fuels, is based on forest biomass. The whole cradle-to-gate chain is included in the analyses. The results indicate that the total amount of biomass required per tonne paper is slightly lower for woodfree than for mechanical paper. For the biomass use per paper area, the paper grammage is decisive. If the grammage can be lowered by increasing the proportion of mechanical pulp, this may lower the biomass use per paper area, despite the higher biomass use per unit mass in mechanical paper. In the production of woodfree paper, energy recovery from residues in the mill accounts for most of the biomass use, while external electricity production accounts for the largest part for mechanical paper. Motor fuel production accounts for 5-7% of the biomass use. The biomass contained in the final paper product is 21-42% of the total biomass use, indicating that waste paper recovery is important. The biomass use was found to be about 15-17% lower for modelled, modern mills compared with mills representative of today's average technology. (author)

  16. The mechanism of photo-energy storage in the Halorhodopsin chloride pump.

    Science.gov (United States)

    Pfisterer, Christoph; Gruia, Andreea; Fischer, Stefan

    2009-05-15

    The light-driven pump Halorhodopsin (hR) uses the energy stored in an initial meta-stable state (K), in which the bound retinal chromophore has been photoisomerized from all-trans to 13-cis, to drive the translocation of one chloride anion across the membrane. Thus far it was unclear whether retinal twisting or charge separation between the positive Schiff base of the retinal and the chloride anion is the primary mechanism of energy storage. Here, combined quantum mechanical/molecular mechanical (QM/MM) simulations show that the energy is predominantly stored by charge separation. However, a large variability in retinal twisting is observed, thus reconciling the contradictory hypotheses for storage. Surprisingly, the energy stored in the K-state amounts to only one-fifth of the photon energy. We explain why the protein cannot store more: even though this would accelerate chloride pumping, raising the K-state also reduces the relative energy barriers against unproductive decay, in particular via the premature cis to trans back-isomerization. Indeed, the protein has maximized its storage so that the back-isomerization barriers are just high enough (> or =18 kcal/mol) to keep the decay rate (1/100 ms) slower than the remaining photocycle (1/20 ms). This need to stabilize the captured photon-energy until it can be used in subsequent steps is inherent to light-driven proteins.

  17. Mechanical energy generation and transfer in the racket arm during table tennis topspin backhands.

    Science.gov (United States)

    Iino, Yoichi; Kojima, Takeji

    2016-06-01

    The ability to generate a high racket speed and a large amount of racket kinetic energy on impact is important for table tennis players. The purpose of this study was to understand how mechanical energy is generated and transferred in the racket arm during table tennis backhands. Ten male advanced right-handed table tennis players hit topspin backhands against pre-impact topspin and backspin balls. The joint kinetics at the shoulder, elbow and wrist of the racket arm was determined using inverse dynamics. A majority of the mechanical energy of the racket arm acquired during forward swing (65 and 77% against topspin and backspin, respectively) was due to energy transfer from the trunk. Energy transfer by the shoulder joint force in the vertical direction was the largest contributor to the mechanical energy of the racket arm against both spins and was greater against backspin than against topspin (34 and 28%, respectively). The shoulder joint force directed to the right, which peaked just before impact, transferred additional energy to the racket. Our results suggest that the upward thrust of the shoulder and the late timing of the axial rotation of the upper trunk are important for an effective topspin backhand.

  18. Influences of trunk flexion on mechanical energy flow in the lower extremities during gait

    Science.gov (United States)

    Takeda, Takuya; Anan, Masaya; Takahashi, Makoto; Ogata, Yuta; Tanimoto, Kenji; Shinkoda, Koichi

    2016-01-01

    [Purpose] The time-series waveforms of mechanical energy generation, absorption, and transfer through the joints indicate how movements are produced and controlled. Previous studies have used these waveforms to evaluate and describe the efficiency of human movements. The purpose of this study was to examine the influence of trunk flexion on mechanical energy flow in the lower extremities during gait. [Subjects and Methods] The subjects were 8 healthy young males (mean age, 21.8 ± 1.3 years, mean height, 170.5 ± 6.8 cm, and mean weight, 60.2 ± 6.8 kg). Subjects walked at a self-selected gait speed under 2 conditions: normal gait (condition N), and gait with trunk flexion formed with a brace to simulate spinal curvature (condition TF). The data collected from initial contact to the mid-stance of gait was analyzed. [Results] There were no significant differences between the 2 conditions in the mechanical energy flow in the knee joint and negative mechanical work in the knee joint. However, the positive mechanical work of the knee joint under condition TF was significantly less than that under condition N. [Conclusion] Trunk flexion led to knee flexion in a standing posture. Thus, a strategy of moving of center of mass upward by knee extension using less mechanical energy was selected during gait in the trunk flexed posture. PMID:27313351

  19. IMPLEMENTING THE ORGANIZATIONAL-ECONOMIC MECHANISM OF ENERGY SECURITY IN IVANO-FRANKIVSK

    Directory of Open Access Journals (Sweden)

    И. М. Мазур

    2014-04-01

    Full Text Available Purpose is to explore the practical experience of forming of organizationally economic mechanism to ensure energy safety based on principles of energy conservation and efficiency of fuel and energy resources use in Ivano-Francovsk city.Methodology includes мethods of synthesis, induction, deduction, analogy, wich used in the study.Results. The active policy of energy efficiency and conservation provides the increase of power safety of city's economy due to reduction of dependence on the consumption of separate types of non-renewable fuel and energy resources. The involvement of international organizations increased the possibility of financing the development and implementation of energy saving measures and improvement of the energy ensuring of the city.Conclusions. A number of organizational and economic problems to ensure power safety are solved by joining the «Agreement of Mayors on sustainable development and climate protection» and the development of Sustainable Energy Programme for 2013 - 2020 years, which includes measures to reduce carbon dioxide emissions by 20 % and local production and consumption of energy. However the efficiency of energy-saving measures and technologies of renewable energy by lowering the price of natural gas is significantly reduced, which leads to increase the payback period almost doubled. Therefore it is necessary to provide administrative and financial leverage to introduce energy-saving technologies: renewable energy in the construction of housing, financial sanctions for excessive fuel consumption and  energy and for production of energy-intensive equipment, environmental penalties for exceeding norms of greenhouse gases and others.Practical implications. The introduction of the mentioned incentives needs the development of the legislative and regulatory support and study the experience of the European countries in  their use.Purchase on Elibrary.ru > Buy now

  20. High-energy electron irradiation of annual plants (bagasse) for an efficient production of chemi-mechanical pulp fibers

    Science.gov (United States)

    Pathak, Shailesh; Ray, A. K.; Großmann, Harald; Kleinert, Rene

    2015-12-01

    The paper industry is one of the largest consumers of energy and energy consumption has been increased several times in last few decades. Bagasse chemical pulping has very low yield about 45-55% and also generates high pollution load in the effluent as compared to mechanical pulping, g. Thermo-mechanical pulp (TMP). On the other hand,-->e.g. thermo-mechanical pulp (TMP). On the other hand, the specific energy consumption is very high for TMP pulps. ETMP (Energy efficient Thermo-Mechanical Pulping) or ECTMP (Energy efficient Chemi-Thermo Mechanical Pulping) is an innovative idea for reducing the energy demand in TMP refining. In the present investigation, energy efficient mechanical pulping potential of bagasse was studied using TMP, CTMP and ECTMP pulping methodology with electron irradiation pretreatment. It is evident from the results that more than 50% energy saving potential of irradiation pre-treatment was achieved.

  1. Estimation of energy requirements for mechanically ventilated, critically ill patients using nutritional status

    Science.gov (United States)

    Kan, Mee-Nin; Chang, Han-Hsin; Sheu, Woei-Fen; Cheng, Chien-Hsiang; Lee, Bor-Jen; Huang, Yi-Chia

    2003-01-01

    Background There is very little information on what is considered an adequate energy intake for mechanically ventilated, critically ill patients. The purpose of the present study was to determine this energy requirement by making use of patients' nutritional status. Methods The study was conducted in a multidisciplinary intensive care unit of Taichung Veterans General Hospital, Taiwan. Patients were hemodynamically stable and not comatose, and were requiring at least 7 days of mechanical ventilation. Fifty-four patients successfully completed this study. The resting energy expenditure was measured using indirect calorimetry. The total energy requirement was considered 120% of the measured energy expenditure. The daily nutrient intake was recorded. Nutritional status was assessed using single and multiple parameters, nitrogen balance, and medical records, and was performed within 24 hours of admission and after 7 days in the intensive care unit. Results Fifteen patients were being underfed (requirement), 20 patients were in the appropriate feeding (AF) group (within ± 10% of total energy requirement), and 19 patients received overfeeding (>110% of total energy requirement). Patients in the underfeeding group received only 68.3% of their energy requirement, while the overfeeding group patients received up to 136.5% of their required calories. Only patients in the AF group had a positive nitrogen balance (0.04 ± 5.1) on day 7. AF group patients had a significantly higher Nutritional Risk Index value at day 7 than at day 1. Conclusion AF patients had more improvement in nutritional status than patients in the other feeding groups. To provide at least 120% of the resting energy expenditure seemed adequate to meet the caloric energy needs of hemodynamically stable, mechanically ventilated, critically ill patients. PMID:12974978

  2. Energy transmission in a mechanically-linked double-wall structure coupled to an acoustic enclosure

    Science.gov (United States)

    Cheng, L.; Li, Y. Y.; Gao, J. X.

    2005-05-01

    The energy transmission in a mechanically linked double-wall structure into an acoustic enclosure is studied in this paper. Based on a fully coupled vibro-acoustic formulation, focus is put on investigating the effect of the air gap and mechanical links between the two panels on the energy transmission and noise insulation properties of such structures. An approximate formula reflecting the gap effect on the lower-order coupled frequencies of the system is proposed. A criterion, based on the ratio between the aerostatic stiffness of the gap cavity and the stiffness of the link, is proposed to predict the dominant transmitting path, with a view to provide guidelines for the design of appropriate control strategies. Numerical results reveal the existence of three distinct zones, within which energy transmission takes place following different mechanisms and transmitting paths. Corresponding effects on noise insulation properties of the double-wall structure are also investigated. .

  3. Research on the business QoS and trustworthy and controllable strategies mechanism for energy internet

    Science.gov (United States)

    Zhang, Geng; Lu, Meiling; Zhang, Dahua; Zhou, Liang; Li, Likang

    2017-01-01

    Energy internet is a kind of power sharing network, which can realize the bidirectional flow of energy information on the basis of the existing power grid. It puts forward higher requirements for reliability and controllability of information communication, and all kinds of business QoS of the backbone network. So the research of business QoS and trustworthy and controllable strategies mechanism have an important significance for the development of energy internet. This paper mainly studies how to use the software defined network (SDN) to achieve business QoS, and provide QoS support for all kinds of business of the energy internet. Combined with the current development situation of the energy internet in our country, this paper researches the trustworthy and controllable strategies mechanism for energy internet, and proposes the transition scheme of the IPv6 credible network architecture based on SDN. This coordinates the contradiction between the growing demand for energy internet applications and the limitations of the energy internet technology itself.

  4. Formation Mechanism and Binding Energy for Body-Centered Cubic Structure of He+9 Cluster

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-Ping; GOU Qing-Quan; LI Ping

    2004-01-01

    The formation mechanism for the body-centered cubic structure of He+9 cluster is proposed and its total energy curve is calculated by the method of a Modified Arrangement Channel Quantum Mechanics. The energy is the function of separation R between the nuclei at the center and an apex of the body-centered cubic structure. The result of the calculation shows that the curve has a minimal energy -25.6669 (a.u.) at R = 2.550ao. The binding energy of He+9 with respect to He+ + 8He was calculated to be 0.8857 a.u. This means that the cluster of He+9 may be formed in the body-centered cubic structure of R = 2.55a0.

  5. A Novel Arch-Shape Nanogenerator Based on Piezoelectric and Triboelectric Mechanism for Mechanical Energy Harvesting.

    Science.gov (United States)

    Xue, Chenyang; Li, Junyang; Zhang, Qiang; Zhang, Zhibo; Hai, Zhenyin; Gao, Libo; Feng, Ruiting; Tang, Jun; Liu, Jun; Zhang, Wendong; Sun, Dong

    2014-12-26

    A simple and cost-effective approach was developed to fabricate piezoelectric and triboelectric nanogenerator (P-TENG) with high electrical output. Additionally, pyramid micro structures fabricated atop a polydimethylsiloxane (PDMS) surface were employed to enhance the device performance. Furthermore, piezoelectric barium titanate (BT) nanoparticles and multiwalled carbon nanotube (MWCNT) were mixed in the PDMS film during the forming process. Meanwhile, the composition of the film was optimized to achieve output performance, and favorable toughness was achieved after thermal curing. An arch-shape ITO/PET electrode was attached to the upper side of the polarized composite film and an aluminum film was placed under it as the bottom electrode. With periodic external force at 20 Hz, electrical output of this P-TENG, reached a peak voltage of 22 V and current of 9 μA with a peak current density of 1.13 μA/cm², which was six times that of the triboelectric generator without BT and MWCNT nanoparticles. The nanogenerator can be directly used to lighten 28 commercial light-emitting diodes (LEDs) without any energy storage unit or rectification circuit under human footfalls.

  6. A Novel Arch-Shape Nanogenerator Based on Piezoelectric and Triboelectric Mechanism for Mechanical Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Chenyang Xue

    2014-12-01

    Full Text Available A simple and cost-effective approach was developed to fabricate piezoelectric and triboelectric nanogenerator (P-TENG with high electrical output. Additionally, pyramid micro structures fabricated atop a polydimethylsiloxane (PDMS surface were employed to enhance the device performance. Furthermore, piezoelectric barium titanate (BT nanoparticles and multiwalled carbon nanotube (MWCNT were mixed in the PDMS film during the forming process. Meanwhile, the composition of the film was optimized to achieve output performance, and favorable toughness was achieved after thermal curing. An arch-shape ITO/PET electrode was attached to the upper side of the polarized composite film and an aluminum film was placed under it as the bottom electrode. With periodic external force at 20 Hz, electrical output of this P-TENG, reached a peak voltage of 22 V and current of 9 μA with a peak current density of 1.13 μA/cm2, which was six times that of the triboelectric generator without BT and MWCNT nanoparticles. The nanogenerator can be directly used to lighten 28 commercial light-emitting diodes (LEDs without any energy storage unit or rectification circuit under human footfalls.

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

    Energy Technology Data Exchange (ETDEWEB)

    Colgate, S.A.; Li, H.

    1998-12-31

    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.

  8. Off Shore wind energy – Case study of cooperation mechanisms design

    DEFF Research Database (Denmark)

    Klinge Jacobsen, Henrik; Hansen, Lise-Lotte Pade; Jansen, Jaap

    2012-01-01

    This document reports activities and results of Task 3.3 of the Intelligent Energy Europe supported project RES4Less. This work is the initial analyses and survey of barriers for implementing cooperation mechanisms in the EU countries. This work builds on earlier Intelligent Energy Europe projects...... also shared and enriched by comments from other members of the RES4Less Team during internal meetings of the project....

  9. Effect of mechanical denaturation on surface free energy of protein powders

    OpenAIRE

    Mohammad, Mohammad Amin; Grimsey, Ian M.; Forbes, Robert T.; Blagbrough, Ian S; Barbara R. Conway

    2016-01-01

    Globular proteins are important both as therapeutic agents and excipients. However, their fragile native\\ud conformations can be denatured during pharmaceutical processing, which leads to modification of\\ud the surface energy of their powders and hence their performance. Lyophilized powders of hen eggwhite\\ud lysozyme and �-galactosidase from Aspergillus oryzae were used as models to study the effects\\ud of mechanical denaturation on the surface energies of basic and acidic protein powders, r...

  10. Energy model of projected transfer with additional mechanical force in the welding process

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on the theory of electrodynamics and other relational subjects,through introducing "Surface Evolver" as the means of FEM analysis, by computing and describing the energy (electromagnetic, gravity, and so on) in the droplet transfer system, an energy model was accomplished for studying the mechanism of projected transfer mode.Furthermore, the behavior of droplet transfer was studied by analyzing its menisci with FEM, and the theoretical results coincide well with the experiment results.

  11. Forces and mechanical energy fluctuations during diagonal stride roller skiing; running on wheels?

    Science.gov (United States)

    Kehler, Alyse L; Hajkova, Eliska; Holmberg, Hans-Christer; Kram, Rodger

    2014-11-01

    Mechanical energy can be conserved during terrestrial locomotion in two ways: the inverted pendulum mechanism for walking and the spring-mass mechanism for running. Here, we investigated whether diagonal stride cross-country roller skiing (DIA) utilizes similar mechanisms. Based on previous studies, we hypothesized that running and DIA would share similar phase relationships and magnitudes of kinetic energy (KE), and gravitational potential energy (GPE) fluctuations, indicating elastic energy storage and return, as if roller skiing is like 'running on wheels'. Experienced skiers (N=9) walked and ran at 1.25 and 3 m s(-1), respectively, and roller skied with DIA at both speeds on a level dual-belt treadmill that recorded perpendicular and parallel forces. We calculated the KE and GPE of the center of mass from the force recordings. As expected, the KE and GPE fluctuated with an out-of-phase pattern during walking and an in-phase pattern during running. Unlike walking, during DIA, the KE and GPE fluctuations were in phase, as they are in running. However, during the glide phase, KE was dissipated as frictional heat and could not be stored elastically in the tendons, as in running. Elastic energy storage and return epitomize running and thus we reject our hypothesis. Diagonal stride cross-country skiing is a biomechanically unique movement that only superficially resembles walking or running.

  12. Reverse electrowetting -- a new approach to high-power harvesting of mechanical energy

    Science.gov (United States)

    Krupenkin, Tom; Taylor, J. Ashley; Manakasettharn, Supone

    2012-02-01

    Over the last decade electrical batteries have emerged as a critical bottleneck in portable electronics development. High-power mechanical energy harvesting can potentially provide a valuable alternative to the use of batteries, but until now, its adoption has been hampered by the lack of an efficient mechanical-to-electrical energy conversion technology. In this talk a novel mechanical-to-electrical energy conversion method is discussed. The method is based on reverse electrowetting (REWOD) -- a novel microfluidic phenomenon. Electrical energy generation is achieved through the interaction of arrays of moving microscopic liquid droplets with novel nanometer-thick multilayer dielectric films. Advantages of this process include the production of high power densities, up to 1 KW sq. m; the ability to directly utilize a very broad range of mechanical forces and displacements; and the ability to directly output a broad range of currents and voltages, from several volts to tens of volts. We hope that the REWOD-based energy harvesting can provide a novel technology platform for a broad range of new electronic products and enable reduction of cost, pollution, and other problems associated with the wide-spread battery use.

  13. Energy storage and dispersion of surface acoustic waves trapped in a periodic array of mechanical resonators

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    2009-01-01

    It has been shown previously that surface acoustic waves can be efficiently trapped and slowed by steep ridges on a piezoelectric substrate, giving rise to two families of shear-horizontal and vertically polarized surface waves. The mechanisms of energy storage and dispersion are explored by using...... as resonators storing mechanical energy. These resonators are evanescently coupled by the surface. The dispersion diagram is presented and shows very low group velocities as the wave vector approaches the limit of the first Brillouin zone. ©2009 American Institute of Physics...

  14. RENEWABLE ENERGY SUPPORT MECHANISM IN TURKEY: FINANCIAL ANALYSIS AND RECOMMENDATIONS TO POLICYMAKERS

    Directory of Open Access Journals (Sweden)

    Mustafa GOZEN

    2014-04-01

    Full Text Available The Turkish Grand National Parliament passed a renewable energy promotion law that provides feed-in tariffs for electricity generation from renewable energy sources in 2005. This law was not attractive to investors due to the low level of feed-in tariffs. Then, in 2011, the promotion law was amended and a new support scheme integrated in the day-ahead market was introduced. Therefore, the main purpose of this article is to explain the new support mechanism, analyze it from the financial perspective, and discuss the related key issues and challenges. In addition, to further improve the support mechanism, some recommendations have been made to policymakers.

  15. Development of mechanical ventilation system with low energy consumption for renovation of buildings

    DEFF Research Database (Denmark)

    Terkildsen, Søren

    the performance of mechanical ventilation systems. The power consumption of mechanical ventilation depends on the flow rate, fan efficiency and pressure loss in the system. This thesis examines the options and develops a concept and components for the design of low-pressure mechanical ventilation. The hypothesis....... Paper I introduces the concept and its performance is evaluated through simulations of a system designed for a test-case building. All the components were designed to minimize pressure losses and therefore the fan power needed to operate the system. The total pressure loss was 30-75 Pa depending......, including ventilation, therefore now represent a larger part of the total energy consumption. Mechanical ventilation has been the most widely used principle of ventilation over the last 50 years, but the conventional system design needs revising to meet future energy requirements. The increase in the use...

  16. Energy Impacts of Envelope Tightening and Mechanical Ventilation for the U.S. Residential Sector

    Energy Technology Data Exchange (ETDEWEB)

    Logue, J. M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherman, M. H. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, I. S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, B. C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-01-01

    Effective residential envelope air sealing reduces infiltration and associated energy costs for thermal conditioning, yet often creates a need for mechanical ventilation to protect indoor air quality. This study estimated the potential energy savings of implementing airtightness improvements or absolute standards along with mechanical ventilation throughout the U.S. housing stock. We used a physics-based modeling framework to simulate the impact of envelope tightening, providing mechanical ventilation as needed. There are 113 million homes in the US. We calculated the change in energy demand for each home in a nationally representative sample of 50,000 virtual homes developed from the 2009 Residential Energy Consumption Survey. Ventilation was provided as required by 2010 and proposed 2013 versions of ASHRAE Standard 62.2. Ensuring that all current homes comply with 62.2-2010 would increase residential site energy demand by 0.07 quads (0.07 exajoules (EJ)) annually. Improving airtightness of all homes at current average retrofit performance levels would decrease demand by 0.7 quads (0.74 EJ) annually and upgrading all homes to be as airtight as the top 10% of similar homes would double the savings, leading to roughly $22 billion in annual savings in energy bills. We also analyzed the potential benefits of bringing the entire stock to airtightness specifications of IECC 2012, Canada's R2000, and Passive House standards.

  17. Prediction-Based Energy Saving Mechanism in 3GPP NB-IoT Networks.

    Science.gov (United States)

    Lee, Jinseong; Lee, Jaiyong

    2017-09-01

    The current expansion of the Internet of things (IoT) demands improved communication platforms that support a wide area with low energy consumption. The 3rd Generation Partnership Project introduced narrowband IoT (NB-IoT) as IoT communication solutions. NB-IoT devices should be available for over 10 years without requiring a battery replacement. Thus, a low energy consumption is essential for the successful deployment of this technology. Given that a high amount of energy is consumed for radio transmission by the power amplifier, reducing the uplink transmission time is key to ensure a long lifespan of an IoT device. In this paper, we propose a prediction-based energy saving mechanism (PBESM) that is focused on enhanced uplink transmission. The mechanism consists of two parts: first, the network architecture that predicts the uplink packet occurrence through a deep packet inspection; second, an algorithm that predicts the processing delay and pre-assigns radio resources to enhance the scheduling request procedure. In this way, our mechanism reduces the number of random accesses and the energy consumed by radio transmission. Simulation results showed that the energy consumption using the proposed PBESM is reduced by up to 34% in comparison with that in the conventional NB-IoT method.

  18. Assessment of Indoor Air Quality Benefits and Energy Costs of Mechanical Ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Logue, J.M.; Price, P.N.; Sherman, M.H.; Singer, B.C.

    2011-07-01

    Intake of chemical air pollutants in residences represents an important and substantial health hazard. Sealing homes to reduce air infiltration can save space conditioning energy, but can also increase indoor pollutant concentrations. Mechanical ventilation ensures a minimum amount of outdoor airflow that helps reduce concentrations of indoor emitted pollutants while requiring some energy for fan(s) and thermal conditioning of the added airflow. This work demonstrates a physics based, data driven modeling framework for comparing the costs and benefits of whole-house mechanical ventilation and applied the framework to new California homes. The results indicate that, on a population basis, the health benefits from reduced exposure to indoor pollutants in New California homes are worth the energy costs of adding mechanical ventilation as specified by ASHRAE Standard 62.2.This study determines the health burden for a subset of pollutants in indoor air and the costs and benefits of ASHRAE's mechanical ventilation standard (62.2) for new California homes. Results indicate that, on a population basis, the health benefits of new home mechanical ventilation justify the energy costs.

  19. Hybrid Quantum Mechanics/Molecular Mechanics Solvation Scheme for Computing Free Energies of Reactions at Metal-Water Interfaces.

    Science.gov (United States)

    Faheem, Muhammad; Heyden, Andreas

    2014-08-12

    We report the development of a quantum mechanics/molecular mechanics free energy perturbation (QM/MM-FEP) method for modeling chemical reactions at metal-water interfaces. This novel solvation scheme combines planewave density function theory (DFT), periodic electrostatic embedded cluster method (PEECM) calculations using Gaussian-type orbitals, and classical molecular dynamics (MD) simulations to obtain a free energy description of a complex metal-water system. We derive a potential of mean force (PMF) of the reaction system within the QM/MM framework. A fixed-size, finite ensemble of MM conformations is used to permit precise evaluation of the PMF of QM coordinates and its gradient defined within this ensemble. Local conformations of adsorbed reaction moieties are optimized using sequential MD-sampling and QM-optimization steps. An approximate reaction coordinate is constructed using a number of interpolated states and the free energy difference between adjacent states is calculated using the QM/MM-FEP method. By avoiding on-the-fly QM calculations and by circumventing the challenges associated with statistical averaging during MD sampling, a computational speedup of multiple orders of magnitude is realized. The method is systematically validated against the results of ab initio QM calculations and demonstrated for C-C cleavage in double-dehydrogenated ethylene glycol on a Pt (111) model surface.

  20. Energy transfer properties and mechanisms. Technical progress report, 1 March 1991--15 August 1993

    Energy Technology Data Exchange (ETDEWEB)

    Barker, J.R.

    1993-12-31

    Since no single experimental technique is the best method for energy transfer experiments, we have used both time-dependent infrared fluorescence (IRF) and time-dependent thermal lensing (TDTL) to study energy transfer in various systems. We are investigating pump-probe techniques employing resonance enhanced multiphoton ionization (REMPI). IRF was used to study benzene, azulene, and toluene. TDTL was used to study CS{sub 2} and SO{sub 2} (data not given for latter). Large molecule energy transfer mechanisms are discussed. 10 figs.

  1. Energy transmission and power sources for mechanical circulatory support devices to achieve total implantability.

    Science.gov (United States)

    Wang, Jake X; Smith, Joshua R; Bonde, Pramod

    2014-04-01

    Left ventricular assist device therapy has radically improved congestive heart failure survival with smaller rotary pumps. The driveline used to power today's left ventricular assist devices, however, continues to be a source of infection, traumatic damage, and rehospitalization. Previous attempts to wirelessly power left ventricular assist devices using transcutaneous energy transfer systems have been limited by restrictions on separation distance and alignment between the transmit and receive coils. Resonant electrical energy transfer allows power delivery at larger distances without compromising safety and efficiency. This review covers the efforts to wirelessly power mechanical circulatory assist devices and the progress made in enhancing their energy sources.

  2. Mechanical properties and energy conversion of 3D close-packed lattice model for brittle rocks

    Science.gov (United States)

    Liu, Chun; Xu, Qiang; Shi, Bin; Deng, Shang; Zhu, Honghu

    2017-06-01

    Numerical simulations using the 3D discrete element method can yield mechanical and dynamic behaviors similar to rocks and grains. In the model, rock is represented by bonded elements, which are arranged on a tetrahedral lattice. The conversion formulas between inter-element parameters and rock mechanical properties were derived. By using the formulas, inter-element parameters can be determined according to mechanical properties of model, including Young's modulus, Poisson's ratio, tensile strength (Tu), compressive strength (Cu) and coefficient of internal friction. The energy conversion rules of the model are proposed. Based on the methods, a Matlab code ;MatDEM; was developed. Numerical models of quartzite were used to validate the formulas. The tested mechanical properties of a single unit correspond reasonably well with the values of quartzite. Tested Tu and Cu with multiple elements are lower than the values predicted by the formulas. In the simulation of rock failure processes, mechanical energy conversed between different forms and heat is generated, but the mechanical energy plus heat always remains constant. Variations of breaking heat and frictional heat provide clues of the fracturing and slipping behaviors of the Tu and Cu tests. The model may be applied to a wide range of geological structures that involve breakage at multiple scales, heat generation and dynamic processes.

  3. Quantum mechanical calculation of nanomaterial-ligand interaction energies by molecular fractionation with conjugated caps method

    Science.gov (United States)

    Zhang, Dawei

    2017-03-01

    Molecular fractionation with conjugate caps (MFCC) method is introduced for the efficient estimation of quantum mechanical (QM) interaction energies between nanomaterial (carbon nanotube, fullerene, and graphene surface) and ligand (charged and neutral). In the calculations, nanomaterials are partitioned into small fragments and conjugated caps that are properly capped, and the interaction energies can be obtained through the summation of QM calculations of the fragments from which the contribution of the conjugated caps is removed. All the calculations were performed by density functional theory (DFT) and dispersion contributions for the attractive interactions were investigated by dispersion corrected DFT method. The predicted interaction energies by MFCC at each computational level are found to give excellent agreement with full system (FS) calculations with the mean energy deviation just a fractional kcal/mol. The accurate determination of nanomaterial-ligand interaction energies by MFCC suggests that it is an effective method for performing QM calculations on nanomaterial-ligand systems.

  4. Plasmon-Induced Resonant Energy Transfer: a coherent dipole-dipole coupling mechanism

    Science.gov (United States)

    Bristow, Alan D.; Cushing, Scott K.; Li, Jiangtian; Wu, Nianqiang

    Metal-insulator-semiconductor core-shell nanoparticles have been used to demonstrate a dipole-dipole coupling mechanism that is entirely dependent on the dephasing time of the localized plasmonic resonance. Consequently, the short-time scale of the plasmons leads to broad energy uncertainty that allows for excitation of charge carriers in the semiconductor via stimulation of photons with energies below the energy band gap. In addition, this coherent energy transfer process overcomes interfacial losses often associated with direct charge transfer. This work explores the efficiency of the energy transfer process, the dipole-dipole coupling strength with dipole separation, shell thickness and plasmonic resonance overlap. We demonstrate limits where the coherent nature of the coupling is switched off and charge transfer processes can dominate. Experiments are performed using transient absorption spectroscopy. Results are compared to calculations using a quantum master equation. These nanostructures show strong potential for improving solar light-harvesting for power and fuel generation.

  5. [Mechanism of intermolecular energy transfer and reception of ultralow action by chemical and biological systems].

    Science.gov (United States)

    Gall', L N; Gall', N R

    2009-01-01

    A novel concept of intermolecular energy transfer and reception of the ultralow action in living systems is proposed. The concept is based on the methods of nonlinear mathematical physics used in description of energy movement along molecular chains and on quantum mechanical ideas concerning signal formation in anisotropic media. A concept of a molecular cell as an indivisible structural unit and a constituent of a biological (chemical) system has been put forward and substantiated, which manifests collective features of the unity of molecules, physical fields, and energetically strained bound water media in processes of energy transfer and reception. Both intermolecular energy transfer and amplification of the ultralow action has been shown to be the components of a unified energy process in a living system, and the physical basis of both processes is the unity of molecules and water-field media in a molecular cell.

  6. Quantum mechanical calculation of nanomaterial-ligand interaction energies by molecular fractionation with conjugated caps method

    Science.gov (United States)

    Zhang, Dawei

    2017-01-01

    Molecular fractionation with conjugate caps (MFCC) method is introduced for the efficient estimation of quantum mechanical (QM) interaction energies between nanomaterial (carbon nanotube, fullerene, and graphene surface) and ligand (charged and neutral). In the calculations, nanomaterials are partitioned into small fragments and conjugated caps that are properly capped, and the interaction energies can be obtained through the summation of QM calculations of the fragments from which the contribution of the conjugated caps is removed. All the calculations were performed by density functional theory (DFT) and dispersion contributions for the attractive interactions were investigated by dispersion corrected DFT method. The predicted interaction energies by MFCC at each computational level are found to give excellent agreement with full system (FS) calculations with the mean energy deviation just a fractional kcal/mol. The accurate determination of nanomaterial-ligand interaction energies by MFCC suggests that it is an effective method for performing QM calculations on nanomaterial-ligand systems. PMID:28300179

  7. Mechanism of Long-Range Penetration of Low-Energy Ions in Botanic Samples

    Institute of Scientific and Technical Information of China (English)

    刘峰; 王宇钢; 薛建明; 王思学; 杜广华; 颜莎; 赵渭江

    2002-01-01

    We present experimental evidence to reveal the mechanism of long-range penetration of low-energy ions in botanic samples. In the 100keV Ar+ ion transmission measurement, the result confirmed that low-energy ions could penetrate at least 60μm thick kidney bean slices with the probability of about 1.0 × 10-5. The energy spectrum of 1 MeV He+ ions penetrating botanic samples has shown that there is a peak of the count of ions with little energy loss. The probability of the low-energy ions penetrating the botanic sample is almost the same as that of the high-energy ions penetrating the same samples with little energy loss. The results indicate that there are some micro-regions with mass thickness less than the projectile range of low-energy ions in the botanic samples and they result in the long-range penetration of low-energy ions in botanic samples.

  8. Design of protein-ligand binding based on the molecular-mechanics energy model.

    Science.gov (United States)

    Boas, F Edward; Harbury, Pehr B

    2008-07-04

    While the molecular-mechanics field has standardized on a few potential energy functions, computational protein design efforts are based on potentials that are unique to individual laboratories. Here we show that a standard molecular-mechanics potential energy function without any modifications can be used to engineer protein-ligand binding. A molecular-mechanics potential is used to reconstruct the coordinates of various binding sites with an average root-mean-square error of 0.61 A and to reproduce known ligand-induced side-chain conformational shifts. Within a series of 34 mutants, the calculation can always distinguish between weak (K(d)>1 mM) and tight (K(d)mechanics potential is used to redesign a ribose-binding site. Out of a search space of 2 x 10(12) sequences, the calculation selects a point mutant of the native protein as the top solution (experimental K(d)=17 microM) and the native protein as the second best solution (experimental K(d)=210 nM). The quality of the predictions depends on the accuracy of the generalized Born electrostatics model, treatment of protonation equilibria, high-resolution rotamer sampling, a final local energy minimization step, and explicit modeling of the bound, unbound, and unfolded states. The application of unmodified molecular-mechanics potentials to protein design links two fields in a mutually beneficial way. Design provides a new avenue for testing molecular-mechanics energy functions, and future improvements in these energy functions will presumably lead to more accurate design results.

  9. EFFICIENCY ANALYSIS OF ENERGY ACCUMULATING MECHANISM FOR TRACTOR WITH ELECTROMECHANICAL TRANSMISSION

    Directory of Open Access Journals (Sweden)

    Ch. I. Zhdanovich

    2017-01-01

    Full Text Available Dependence of tractor wheel torque on theoretical tractor motion speed has been used for comparison of tractor operation with electromechanical transmission with installation of energy accumulating mechanism and without its installation. In this case a traction asynchronous electric motor is operating under nominal and limit conditions. The paper also considers dependence diagrams of actual input power for the traction asynchronous electric motor and its losses due to theoretical tractor motion speed. Tractor wheel torque is limited during the operation of the traction asynchronous electric motor with energy accumulating mechanisms by the following factors: maximum electric motor torque at the given frequency of supply voltage; maximum value of internal combustion motor output which can be transferred to the traction asynchronous electric motor; grip of the wheels. During the operation of the traction asynchronous electric motor with energy accumulating mechanisms there is a possibility for short power consumption without regard to the second limitation because it is possible to use power not only of internal combustion motor but also the power which is stored in the energy accumulating mechanisms. Comparison of characteristics has been made when a tractor is operating at high gear and when it is operating at all gears (that is two gears. Operation of the 5th class tractors has been analyzed for all possible cases (operation with energy accumulating mechanisms and without the mechanisms while being operated at all gears and various types of work: tilling, sowing, cultivation, bulldozing work, transport mode. In this case equipment has been used which is aggregated with the 5th class tractor. 

  10. Energy harvesting through a backpack employing a mechanically amplified piezoelectric stack

    Science.gov (United States)

    Feenstra, Joel; Granstrom, Jon; Sodano, Henry

    2008-04-01

    Over the past few decades, the use of portable and wearable electronics has grown steadily. These devices are becoming increasingly more powerful, however, the gains that have been made in the device performance has resulted in the need for significantly higher power to operate the electronics. This issue has been further complicated due to the stagnate growth of battery technology over the past decade. In order to increase the life of these electronics, researchers have begun investigating methods of generating energy from ambient sources such that the life of the electronics can be prolonged. Recent developments in the field have led to the design of a number of mechanisms that can be used to generate electrical energy, from a variety of sources including thermal, solar, strain, inertia, etc. Many of these energy sources are available for use with humans, but their use must be carefully considered such that parasitic effects that could disrupt the user's gait or endurance are avoided. This study develops a novel energy harvesting backpack that can generate electrical energy from the differential forces between the wearer and the pack. The goal of this system is to make the energy harvesting device transparent to the wearer such that his or her endurance and dexterity is not compromised. This will be accomplished by replacing the strap buckle with a mechanically amplified piezoelectric stack actuator. Piezoelectric stack actuators have found little use in energy harvesting applications due to their high stiffness which makes straining the material difficult. This issue will be alleviated using a mechanically amplified stack which allows the relatively low forces generated by the pack to be transformed to high forces on the piezoelectric stack. This paper will develop a theoretical model of the piezoelectric buckle and perform experimental testing to validate the model accuracy and energy harvesting performance.

  11. A Novel Self-Powered Wireless Sensor Node Based on Energy Harvesting for Mechanical Vibration Monitoring

    Directory of Open Access Journals (Sweden)

    Xihai Zhang

    2014-01-01

    Full Text Available Wireless sensor networks (WSNs have been expected to improve the capability of capturing mechanical vibration dynamic behaviors and evaluating the current health status of equipment. While the expectation for mechanical vibration monitoring using WSNs has been high, one of the key limitations is the limited lifetime of batteries for sensor node. The energy harvesting technologies have been recently proposed. One of them shares the same main idea, that is, energy harvesting from ambient vibration can be converted into electric power. Employing the vibration energy harvesting, a novel self-powered wireless sensor node has been developed to measure mechanical vibration in this paper. The overall architecture of node is proposed. The wireless sensor node is described into four main components: the energy harvesting unit, the microprocessor unit, the radio transceiver unit, and accelerometer. Moreover, the software used to control the operation of wireless node is also suggested. At last, in order to achieve continuous self-powered for nodes, two operation modes including the charging mode and discharging mode are proposed. This design can effectively solve the problem of continuous supply power of sensor node for mechanical vibration monitoring.

  12. The Energy Transfer Processes between Carotenoid and Chlorophyll Regulated by Electron Exchange Mechanism

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The energy transfer efficiency between carotenoids and chlorophyll depend on temperature and viscosity of the media. A 3.5 ps process was detected by the pico-second time-resolved spectra and the process was proved to be regulated by electron exchange mechanism.

  13. Mechanical properties of carbynes investigated by ab initio total-energy calculations

    DEFF Research Database (Denmark)

    Castelli, Ivano E.; Salvestrini, Paolo; Manini, Nicola

    2012-01-01

    As sp carbon chains (carbynes) are relatively rigid molecular objects, can we exploit them as construction elements in nanomechanics? To answer this question, we investigate their remarkable mechanical properties by ab initio total-energy simulations. In particular, we evaluate their linear...

  14. COMPARISON OF ENERGY AND EXERGY EFFICIENCIES OF ABSORPTION REFRIGERATION SYSTEM WITH MECHANICAL COMPRESSION REFRIGERATION SYSTEM

    Directory of Open Access Journals (Sweden)

    Gülay YAKAR

    2005-02-01

    Full Text Available In this study, energy and exergy analysis of absorption refrigeration system using LiBr- water and mechanical compression refrigeration system using R134-a were performed at different evaporation temperatures. The results are presented in tables and figures.

  15. Designing New Materials for Converting Solar Energy to Fuels via Quantum Mechanics

    Science.gov (United States)

    2014-07-11

    grant was the first to the PI to use first principles quantum mechanics to characterize key atomic-scale elementary processes involved in photocatalysis ...free energies for reduction and oxidation determines whether photocatalysis is thermodynamically allowed. • Finally, we calculate surface redox... photocatalysis , given its improved conductivity properties compared to hematite. Summary Concepts and findings developed during this grant were

  16. Energy transfer mechanism for downconversion in the (Pr3+, Yb3+) couple

    NARCIS (Netherlands)

    Van Wijngaarden, J.T.; Scheidelaar, S.; Vlugt, T.J.H.; Reid, M.F.; Meijerink, A.

    2010-01-01

    Downconversion of one visible photon into two infrared photons has been reported for the lanthanide ion couple (Pr3+, Yb3+) in a variety of host lattices. The mechanism responsible for downconversion is controversial and has been reported to be either a two-step energy transfer process (via two firs

  17. A Combined Softening and Hardening Mechanism for Low Frequency Human Motion Energy Harvesting Application

    Directory of Open Access Journals (Sweden)

    Khalis Suhaimi

    2014-01-01

    Full Text Available This paper concerns the mechanism for harvesting energy from human body motion. The vibration signal from human body motion during walking and jogging was first measured using 3-axes vibration recorder placed at various places on the human body. The measured signal was then processed using Fourier series to investigate its frequency content. A mechanism was proposed to harvest the energy from the low frequency-low amplitude human motion. This mechanism consists of the combined nonlinear hardening and softening mechanism which was aimed at widening the bandwidth as well as amplifying the low human motion frequency. This was realized by using a translation-to-rotary mechanism which converts the translation motion of the human motion into the rotational motion. The nonlinearity in the system was realized by introducing a winding spring stiffness and the magnetic stiffness. Quasi-static and dynamic measurement were conducted to investigate the performance of the mechanism. The results show that, with the right degree of nonlinearity, the two modes can be combined together to produce a wide flat response. For the frequency amplification, the mechanism manages to increase the frequency by around 8 times in terms of rotational speed.

  18. Combining Technologies to Deliver Distance Education

    Directory of Open Access Journals (Sweden)

    Vicki Freeman

    1999-01-01

    Full Text Available In 1997 a Health Resources and Services Administration (HRSA grant was awarded to the Department of Clinical Laboratory Sciences (CLS at The University of Texas Medical Branch - Galveston (UTMB for support of the Laboratory Education and Advancement Project (LEAP. The project entailed three primary objectives, targeting laboratory practitioners in rural and medically underserved areas of Texas for delivering a bachelor's degree, laboratory-intensive course of study via distance education. Several delivery mechanisms were utilized and evaluated for their effectiveness and friendliness to both the faculty and students. The authors discuss and describe the mechanisms utilized for delivery of courses, the advantages and disadvantages encountered with each mechanism, and subjective evaluation of the effectiveness of the courses. Also discussed are the lessons learned and plans for future development.

  19. Anaerobic energy expenditure and mechanical efficiency during exhaustive leg press exercise

    DEFF Research Database (Denmark)

    Gorostiaga, Esteban M.; Navarro-Amézqueta, Ion; Cusso, Roser

    2010-01-01

    Information about anaerobic energy production and mechanical efficiency that occurs over time during short-lasting maximal exercise is scarce and controversial. Bilateral leg press is an interesting muscle contraction model to estimate anaerobic energy production and mechanical efficiency during...... maximal exercise because it largely differs from the models used until now. This study examined the changes in muscle metabolite concentration and power output production during the first and the second half of a set of 10 repetitions to failure (10RM) of bilateral leg press exercise. On two separate days...... average duration of exercise (18.4 ± 4.0 vs 14.2 ± 2.1 s). These data indicate that during a set of 10RM of bilateral leg press exercise there is a decrease in power output which is associated with a decrease in the contribution of PCr and/or an increase in muscle lactate. The higher energy cost per...

  20. Mechanosensing and mechanochemical transduction: how is mechanical energy sensed and converted into chemical energy in an extracellular matrix?

    Science.gov (United States)

    Silver, Frederick H; Siperko, Lorraine M

    2003-01-01

    Gravity plays a central role in vertebrate development and evolution. Gravitational forces acting on mammalian tissues cause the net muscle forces required for locomotion to be higher on earth than on a body subjected to a microgravitational field. As body mass increases during development, the musculoskeleton must be able to adapt by increasing the size of its functional units. Thus mechanical forces required to do the work (mechanical energy) of locomotion must be sensed by cells and converted into chemical energy (synthesis of new tissue). Extracellular matrices (ECMs) are multicomponent tissues that transduce internal and external mechanical signals into changes in tissue structure and function through a process termed mechanochemical transduction. Under the influence of an external gravitational field, both mineralized and unmineralized vertebrate tissues exhibit internal tensile forces that serve to preserve a synthetic phenotype in the resident cell population. Application of additional external forces alters the balance between the external gravitational force and internal forces acting on resident cells leading to changes in the expression of genes and production of protein that ultimately may alter the exact structure and function of the extracellular matrix. Changes in the equilibrium between internal and external forces acting on ECMs and changes in mechanochemical transduction processes at the cellular level appear to be important mechanisms by which mammals adjust their needs to store, transmit, and dissipate energy that is required during development and for bodily movements. Mechanosensing is postulated to involve many different cellular and extracellular components. Mechanical forces cause direct stretching of protein-cell surface integrin binding sites that occur on all eukaryotic cells. Stress-induced conformational changes in the extracellular matrix may alter integrin structure and lead to activation of several secondary messenger pathways

  1. Phase Transitions as a Novel Mechanism for High-Speed Energy Storage

    Science.gov (United States)

    Bernholc, Jerry

    2013-03-01

    In many energy applications there is an urgent need to store and quickly discharge large amounts of electrical energy. Since capacitors can be discharged far quicker than batteries and fuel cells, they have much higher power densities. At present, highly insulating polymers with large breakdown fields, such as polypropylene, are the dielectrics of choice in high-power capacitors. However, their energy densities are quite low because of small dielectric constants. Ferroelectric polymers from the PVDF family have significantly larger dielectric constants, yet their energy densities are still rather low. This can be traced to early saturation of their displacement fields with the applied electric field, and to somewhat lower breakdown fields. However, an admixture of a small amount of another polymer, such as CTFE, results in a dramatic increase in the stored energy. We show that this highly non-linear increase in the energy density is due to the formation of disordered nanodomains with different copolymer concentrations, which undergo first-order non-polar to polar phase transitions with an increase of the applied field. The resulting energy density profile reproduces well the experimental data, while its variation with co-polymer concentration and distribution suggest avenues for additional substantial improvements in the stored energy. Most recently, we have identified a low-activation-energy pathway for these successive phase transformations. It provides further confirmation of the viability of the suggested energy storage mechanism and also enables fine-tuning of the kinetics of energy release by informed choices of suitable co-polymers. In collaboration with V. Ranjan, L. Yu, M. Buongiorno Nardelli and R. Dong.

  2. Contribution of the forelimbs and hindlimbs of the horse to mechanical energy changes in jumping.

    Science.gov (United States)

    Bobbert, Maarten F; Santamaría, Susana

    2005-01-01

    The purpose of the present study was to gain more insight into the contribution of the forelimbs and hindlimbs of the horse to energy changes during the push-off for a jump. For this purpose, we collected kinematic data at 240 Hz from 23 5-year-old Warmbloods (average mass: 595 kg) performing free jumps over a 1.15 m high fence. From these data, we calculated the changes in mechanical energy and the changes in limb length and joint angles. The force carried by the forelimbs and the amount of energy stored was estimated from the distance between elbow and hoof, assuming that this part of the leg behaved as a linear spring. During the forelimb push, the total energy first decreased by 3.2 J kg(-1) and then increased again by 4.2 J kg(-1) to the end of the forelimb push. At the end of the forelimb push, the kinetic energy due to horizontal velocity of the centre of mass was 1.6 J kg(-1) less than at the start, while the effective energy (energy contributing to jump height) was 2.3 J kg(-1) greater. It was investigated to what extent these changes could involve passive spring-like behaviour of the forelimbs. The amount of energy stored and re-utilized in the distal tendons during the forelimb push was estimated to be on average 0.4 J kg(-1) in the trailing forelimb and 0.23 J kg(-1) in the leading forelimb. This means that a considerable amount of energy was first dissipated and subsequently regenerated by muscles, with triceps brachii probably being the most important contributor. During the hindlimb push, the muscles of the leg were primarily producing energy. The total increase in energy was 2.5 J kg(-1) and the peak power output amounted to 71 W kg(-1).

  3. Theoretical analysis and numerical simulation of mechanical energy loss and wall resistance of steady open channel flow

    Institute of Scientific and Technical Information of China (English)

    刘士和; 薛娇

    2016-01-01

    The mechanical energy loss and the wall resistance are very important in practical engineering. These problems are investigated through theoretical analysis and numerical simulation in this paper. The results are as follows. (1) A new mechanical energy equation for the total flow is obtained, and a general formula for the calculation of the mechanical energy loss is proposed. (2) The general relationship between the wall resistance and the mechanical energy loss for the steady channel flow is obtained, the simplified form of which for the steady uniform channel flow is in consistent with the formula used in Hydraulics deduced byπ theorem and dimensional analysis. (3) The steady channel flow over a backward facing step with a small expansion ratio is numerica- lly simulated, and the mechanical energy loss, the wall resistance as well as the relationship between the wall resistance and the mechanical energy loss are calculated and analyzed.

  4. Financial Analysis of Incentive Mechanisms to Promote Energy Efficiency: Case Study of a Prototypical Southwest Utility

    Energy Technology Data Exchange (ETDEWEB)

    Cappers, Peter; Goldman, Charles; Chait, Michele; Edgar, George; Schlegel, Jeff; Shirley, Wayne

    2009-03-04

    Many state regulatory commissions and policymakers want utilities to aggressively pursue energy efficiency as a strategy to mitigate demand and energy growth, diversify the resource mix, and provide an alternative to building new, costly generation. However, as the National Action Plan for Energy Efficiency (NAPEE 2007) points out, many utilities continue to shy away from aggressively expanding their energy efficiency efforts when their shareholder's fundamental financial interests are placed at risk by doing so. Thus, there is increased interest in developing effective ratemaking and policy approaches that address utility disincentives to pursue energy efficiency or lack of incentives for more aggressive energy efficiency efforts. New regulatory initiatives to promote increased utility energy efficiency efforts also affect the interests of consumers. Ratepayers and their advocates are concerned with issues of fairness, impacts on rates, and total consumer costs. From the perspective of energy efficiency advocates, the quid pro quo for utility shareholder incentives is the obligation to acquire all, or nearly all, achievable cost-effective energy efficiency. A key issue for state regulators and policymakers is how to maximize the cost-effective energy efficiency savings attained while achieving an equitable sharing of benefits, costs and risks among the various stakeholders. In this study, we modeled a prototypical vertically-integrated electric investor-owned utility in the southwestern US that is considering implementing several energy efficiency portfolios. We analyze the impact of these energy efficiency portfolios on utility shareholders and ratepayers as well as the incremental effect on each party when lost fixed cost recovery and/or utility shareholder incentive mechanisms are implemented. A primary goal of our quantitative modeling is to provide regulators and policymakers with an analytic framework and tools that assess the financial impacts of

  5. Energy transfer mechanism and probability analysis of submarine pipe laterally impacted by dropped objects

    Science.gov (United States)

    Liang, Jing; Yu, Jian-xing; Yu, Yang; Lam, W.; Zhao, Yi-yu; Duan, Jing-hui

    2016-06-01

    Energy transfer ratio is the basic-factor affecting the level of pipe damage during the impact between dropped object and submarine pipe. For the purpose of studying energy transfer and damage mechanism of submarine pipe impacted by dropped objects, series of experiments are designed and carried out. The effective yield strength is deduced to make the quasi-static analysis more reliable, and the normal distribution of energy transfer ratio caused by lateral impact on pipes is presented by statistic analysis of experimental results based on the effective yield strength, which provides experimental and theoretical basis for the risk analysis of submarine pipe system impacted by dropped objects. Failure strains of pipe material are confirmed by comparing experimental results with finite element simulation. In addition, impact contact area and impact time are proved to be the major influence factors of energy transfer by sensitivity analysis of the finite element simulation.

  6. An investigation into student understanding of energy in the context of mechanics

    Science.gov (United States)

    Lindsey, Beth A.

    This dissertation describes an investigation into student understanding of energy in the context of an introductory calculus-based mechanics course. Through the administration of written and on-line questions, a variety of student difficulties with the concept of energy were identified. Many of these difficulties relate to student ability to calculate the work done on an extended system and to recognize the implications of a particular choice of system. These findings prompted revisions to existing curriculum and guided the creation of new tutorials to address many of the difficulties identified by research. Results indicate that the modified tutorial sequence has been quite successful in addressing student difficulties related to the definition of work and moderately successful in improving understanding of the relationship between work and energy. They also suggest that lingering difficulties with the relationship between work and energy may be closely linked to the persistence of an inability to interpret correctly the implications of the choice of system.

  7. Analytical mechanics and field theory: derivation of equations from energy conservation

    Science.gov (United States)

    Vinokurov, N. A.

    2014-06-01

    Equations of motion in mechanics and field equations in field theory are conventionally derived using the least action principle. This paper presents a nonvariational derivation of Hamilton's and Lagrange's equations. The derivation starts by specifying the system energy as a function of generalized coordinates and velocities and then introduces generalized momenta in such a way that the energy remains unchanged under variations of any degree of freedom. This immediately leads to Hamilton's equations with an as yet undefined Hamiltonian. The explicit dependence of generalized momenta on the coordinates and velocities is determined by first finding the Lagrangian from the known energy function. We discuss electrodynamics as an illustrative example. The proposed approach provides new insight into the nature of canonical momenta and offers a way to find the Lagrangian from the known energy of the system.

  8. Production mechanism of hot nuclei in violent collisions in the Fermi energy domain

    Science.gov (United States)

    Veselsky, M.

    2002-07-01

    A production mechanism of highly excited nuclei formed in violent collisions in the Fermi energy domain is investigated. The collision of two nuclei is decomposed into several stages which are treated separately. Simplified exciton concept is used for the description of pre-equilibrium emission. A modified spectator-participant scenario is used where motion along classical Coulomb trajectories is assumed. The participant and one of the spectator zones undergo incomplete fusion. Excitation energies of both cold and hot fragment are determined. Results of the calculation are compared to recent experimental data in the Fermi energy domain. Data on hot projectile-like, mid-velocity and fusion-like sources are described consistently. Geometric aspects of pre-equilibrium emission are revealed. Explanations to previously unexplained experimental phenomena are given. Energy deposited into non-thermal degrees of freedom is estimated.

  9. Prediction of Tetraoxygen Reaction Mechanism with Sulfur Atom on the Singlet Potential Energy Surface

    Directory of Open Access Journals (Sweden)

    Ashraf Khademzadeh

    2014-01-01

    Full Text Available The mechanism of S+O4 (D2h reaction has been investigated at the B3LYP/6-311+G(3df and CCSD levels on the singlet potential energy surface. One stable complex has been found for the S+O4 (D2h reaction, IN1, on the singlet potential energy surface. For the title reaction, we obtained four kinds of products at the B3LYP level, which have enough thermodynamic stability. The results reveal that the product P3 is spontaneous and exothermic with −188.042 and −179.147 kcal/mol in Gibbs free energy and enthalpy of reaction, respectively. Because P1 adduct is produced after passing two low energy level transition states, kinetically, it is the most favorable adduct in the 1S+1O4 (D2h atmospheric reactions.

  10. Toward an Automatic Determination of Enzymatic Reaction Mechanisms and Their Activation Free Energies.

    Science.gov (United States)

    Zinovjev, Kirill; Ruiz-Pernía, J Javier; Tuñón, Iñaki

    2013-08-13

    We present a combination of the string method and a path collective variable for the exploration of the free energy surface associated to a chemical reaction in condensed environments. The on-the-fly string method is employed to find the minimum free energy paths on a multidimensional free energy surface defined in terms of interatomic distances, which is a convenient selection to study bond forming/breaking processes. Once the paths have been determined, a reaction coordinate is defined as a measure of the advance of the system along these paths. This reaction coordinate can be then used to trace the reaction Potential of Mean Force from which the activation free energy can be obtained. This combination of methodologies has been here applied to the study, by means of Quantum Mechanics/Molecular Mechanics simulations, of the reaction catalyzed by guanidinoacetate methyltransferase. This enzyme catalyzes the methylation of guanidinoacetate by S-adenosyl-l-methionine, a reaction that involves a methyl transfer and a proton transfer and for which different reaction mechanisms have been proposed.

  11. Reaction mechanism and reaction coordinates from the viewpoint of energy flow.

    Science.gov (United States)

    Li, Wenjin; Ma, Ao

    2016-03-21

    Reaction coordinates are of central importance for correct understanding of reaction dynamics in complex systems, but their counter-intuitive nature made it a daunting challenge to identify them. Starting from an energetic view of a reaction process as stochastic energy flows biased towards preferred channels, which we deemed the reaction coordinates, we developed a rigorous scheme for decomposing energy changes of a system, both potential and kinetic, into pairwise components. The pairwise energy flows between different coordinates provide a concrete statistical mechanical language for depicting reaction mechanisms. Application of this scheme to the C7eq → C7ax transition of the alanine dipeptide in vacuum revealed novel and intriguing mechanisms that eluded previous investigations of this well studied prototype system for biomolecular conformational dynamics. Using a cost function developed from the energy decomposition components by proper averaging over the transition path ensemble, we were able to identify signatures of the reaction coordinates of this system without requiring any input from human intuition.

  12. ACOUSTIC RADIATION ENERGY AT A VARIATION OF THE COMPOSITE MECHANICAL DESTRUCTION AREA

    Directory of Open Access Journals (Sweden)

    Sergii Filonenko

    2016-06-01

    Full Text Available Purpose: The technological parameters of composite materials machining and also cutting tool state determine deforming and destruction of their surface layers conditions. Change of this conditions results to appearance of miscellaneous defects, loss of quality and produced items reliability. Therefore, optimization, control, diagnosis and monitoring of composite materials machining technological parameters are directed on obtaining the items given quality. For the solution of these problems tasks carry out researches of technological processes with usage of different methods. One of such methods is the acoustic emission method. Methods: The simulation and analysis of acoustic radiation energy parameters is carried out at change of composite material machining depth for prevailing mechanical destruction its surface layer. Results: We showed that to composite material machining the acoustic radiation energy has continuous nature. The ascending of composite material machining depth results to increase of acoustic emission statistical energy parameters. The regularity of acoustic emission energy parameters change are obtained and described. Is showed, that acoustic radiation most sensing parameter is the acoustic emission signals energy average level dispersion. Discussion: The outcomes researches demonstrate regularity influencing of composite material machining depth on acoustic emission energy parameters. Thus the analysis of acoustic emission signals energy average level dispersion can be used at mining methods of diagnostic, monitoring and control of composite materials machining technological parameters.

  13. Outstanding mechanical properties of monolayer MoS2 and its application in elastic energy storage.

    Science.gov (United States)

    Peng, Qing; De, Suvranu

    2013-11-28

    The structural and mechanical properties of graphene-like honeycomb monolayer structures of MoS2 (g-MoS2) under various large strains are investigated using density functional theory (DFT). g-MoS2 is mechanically stable and can sustain extra large strains: the ultimate strains are 0.24, 0.37, and 0.26 for armchair, zigzag, and biaxial deformation, respectively. The in-plane stiffness is as high as 120 N m(-1) (184 GPa equivalently). The third, fourth, and fifth order elastic constants are indispensable for accurate modeling of the mechanical properties under strains larger than 0.04, 0.07, and 0.13 respectively. The second order elastic constants, including in-plane stiffness, are predicted to monotonically increase with pressure while the Poisson ratio monotonically decreases with increasing pressure. With the prominent mechanical properties including large ultimate strains and in-plane stiffness, g-MoS2 is a promising candidate of elastic energy storage for clean energy. It possesses a theoretical energy storage capacity as high as 8.8 MJ L(-1) and 1.7 MJ kg(-1), or 476 W h kg(-1), larger than a Li-ion battery and is environmentally friendly.

  14. Methods for Efficiently and Accurately Computing Quantum Mechanical Free Energies for Enzyme Catalysis.

    Science.gov (United States)

    Kearns, F L; Hudson, P S; Boresch, S; Woodcock, H L

    2016-01-01

    Enzyme activity is inherently linked to free energies of transition states, ligand binding, protonation/deprotonation, etc.; these free energies, and thus enzyme function, can be affected by residue mutations, allosterically induced conformational changes, and much more. Therefore, being able to predict free energies associated with enzymatic processes is critical to understanding and predicting their function. Free energy simulation (FES) has historically been a computational challenge as it requires both the accurate description of inter- and intramolecular interactions and adequate sampling of all relevant conformational degrees of freedom. The hybrid quantum mechanical molecular mechanical (QM/MM) framework is the current tool of choice when accurate computations of macromolecular systems are essential. Unfortunately, robust and efficient approaches that employ the high levels of computational theory needed to accurately describe many reactive processes (ie, ab initio, DFT), while also including explicit solvation effects and accounting for extensive conformational sampling are essentially nonexistent. In this chapter, we will give a brief overview of two recently developed methods that mitigate several major challenges associated with QM/MM FES: the QM non-Boltzmann Bennett's acceptance ratio method and the QM nonequilibrium work method. We will also describe usage of these methods to calculate free energies associated with (1) relative properties and (2) along reaction paths, using simple test cases with relevance to enzymes examples. © 2016 Elsevier Inc. All rights reserved.

  15. Effect of the upper limbs muscles activity on the mechanical energy gain in pole vaulting.

    Science.gov (United States)

    Frère, Julien; Göpfert, Beat; Slawinski, Jean; Tourny-chollet, Claire

    2012-04-01

    The shoulder muscles are highly solicited in pole vaulting and may afford energy gain. The objective of this study was to determine the bilateral muscle activity of the upper-limbs to explain the actions performed by the vaulter to bend the pole and store elastic energy. Seven experienced athletes performed 5-10 vaults which were recorded using two video cameras (50Hz). The mechanical energy of the centre of gravity (CG) was computed, while surface electromyographic (EMG) profiles were recorded from 5 muscles bilateral: deltoideus, infraspinatus, biceps brachii, triceps, and latissimus dorsi muscles. The level of intensity from EMG profile was retained in four sub phases between take-off (TO1) and complete pole straightening (PS). The athletes had a mean mechanical energy gain of 22% throughout the pole vault, while the intensities of deltoideus, biceps brachii, and latissimus dorsi muscles were sub phases-dependent (pmechanical energy of the vaulter could be linked to an increase in muscle activation, especially from latissimusdorsi muscles. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. Micro electro-mechanical system piezoelectric cantilever array for a broadband vibration energy harvester.

    Science.gov (United States)

    Chun, Inwoo; Lee, Hyun-Woo; Kwon, Kwang-Ho

    2014-12-01

    Limited energy sources of ubiquitous sensor networks (USNs) such as fuel cells and batteries have grave drawbacks such as the need for replacements and re-charging owing to their short durability and environmental pollution. Energy harvesting which is converting environmental mechanical vibration into electrical energy has been researched with some piezoelectric materials and various cantilever designs to increase the efficiency of energy-harvesting devices. In this study, we focused on an energy-harvesting cantilever with a broadband vibration frequency. We fabricated a lead zirconate titanate (PZT) cantilever array with various Si proof masses on small beams (5.5 mm x 0.5 mm x 0.5 mm). We obtained broadband resonant frequencies ranging between 127 Hz and 136 Hz using a micro electro-mechanical system (MEMS) process. In order to obtain broadband resonant characteristics, the cantilever array was comprised of six cantilevers with different resonant frequencies. We obtained an output power of about 2.461 μW at an acceleration of 0.23 g and a resistance of 4 kΩ. The measured bandwidth of the resonant frequency was approximately 9 Hz (127-136 Hz), which is about six times wider than the bandwidth of a single cantilever.

  17. Fundamental reaction mechanism and free energy profile for (-)-cocaine hydrolysis catalyzed by cocaine esterase.

    Science.gov (United States)

    Liu, Junjun; Hamza, Adel; Zhan, Chang-Guo

    2009-08-26

    The fundamental reaction mechanism of cocaine esterase (CocE)-catalyzed hydrolysis of (-)-cocaine and the corresponding free energy profile have been studied by performing pseudobond first-principles quantum mechanical/molecular mechanical free energy (QM/MM-FE) calculations. On the basis of the QM/MM-FE results, the entire hydrolysis reaction consists of four reaction steps, including the nucleophilic attack on the carbonyl carbon of (-)-cocaine benzoyl ester by the hydroxyl group of Ser117, dissociation of (-)-cocaine benzoyl ester, nucleophilic attack on the carbonyl carbon of (-)-cocaine benzoyl ester by water, and finally dissociation between the (-)-cocaine benzoyl group and Ser117 of CocE. The third reaction step involving the nucleophilic attack of a water molecule was found to be rate-determining, which is remarkably different from (-)-cocaine hydrolysis catalyzed by wild-type butyrylcholinesterase (BChE; where the formation of the prereactive BChE-(-)-cocaine complex is rate-determining) or its mutants containing Tyr332Gly or Tyr332Ala mutation (where the first chemical reaction step is rate-determining). Besides, the role of Asp259 in the catalytic triad of CocE does not follow the general concept of the "charge-relay system" for all serine esterases. The free energy barrier calculated for the rate-determining step of CocE-catalyzed hydrolysis of (-)-cocaine is 17.9 kcal/mol, which is in good agreement with the experimentally derived activation free energy of 16.2 kcal/mol. In the present study, where many sodium ions are present, the effects of counterions are found to be significant in determining the free energy barrier. The finding of the significant effects of counterions on the free energy barrier may also be valuable in guiding future mechanistic studies on other charged enzymes.

  18. Gait models and mechanical energy in three cross-country skiing techniques.

    Science.gov (United States)

    Pellegrini, Barbara; Zoppirolli, Chiara; Bortolan, Lorenzo; Zamparo, Paola; Schena, Federico

    2014-11-01

    Fluctuations in mechanical energy of the body center of mass (COM) have been widely analyzed when investigating different gaits in human and animal locomotion. We applied this approach to estimate the mechanical work in cross-country skiing and to identify the fundamental mechanisms of this particular form of locomotion. We acquired movements of body segments, skis, poles and plantar pressures for eight skiers while they roller skied on a treadmill at 14 km h(-1) and a 2 deg slope using three different techniques (diagonal stride, DS; double poling, DP; double poling with kick, DK). The work associated with kinetic energy (KE) changes of COM was not different between techniques; the work against gravity associated with potential energy (PE) changes was higher for DP than for DK and was lowest for DS. Mechanical work against the external environment was 0.87 J m(-1) kg(-1) for DS, 0.70 J m(-1) kg(-1) for DP and 0.79 J m(-1) kg(-1) for DK. The work done to overcome frictional forces, which is negligible in walking and running, was 17.8%, 32.3% and 24.8% of external mechanical work for DS, DP and DK, respectively. The pendulum-like recovery (R%) between PE and KE was ~45%, ~26% and ~9% for DP, DK and DS, respectively, but energy losses by friction are not accounted for in this computation. The pattern of fluctuations of PE and KE indicates that DS can be described as a 'grounded running', where aerial phases are substituted by ski gliding phases, DP can be described as a pendular gait, whereas DK is a combination of both.

  19. Hydrophobic polymer covered by a grating electrode for converting the mechanical energy of water droplets into electrical energy

    Science.gov (United States)

    Helseth, L. E.; Guo, X. D.

    2016-04-01

    Water contact electric harvesting has a great potential as a new energy technology for powering small-scale electronics, but a better understanding of the dynamics governing the conversion from mechanical to electrical energy on the polymer surfaces is needed. Important questions are how current correlates with droplet kinetic energy and what happens to the charge dynamics when a large number of droplets are incident on the polymer simultaneously. Here we address these questions by studying the current that is generated in an external electrical circuit when water droplets impinge on hydrophobic fluorinated ethylene propylene film containing a grating electrode on the back side. Droplets moving down an inclined polymer plane exhibit a characteristic periodic current time trace, and it is found that the peak current scales with sine of the inclination angle. For single droplets in free fall impinging onto the polymer, it is found that the initial peak current scales with the height of the free fall. The transition from individual droplets to a nearly continuous stream was investigated using the spectral density of the current signal. In both regimes, the high frequency content of the spectral density scales as f -2. For low frequencies, the low frequency content at low volume rates was noisy but nearly constant, whereas for high volume rates an increase with frequency is observed. It is demonstrated that the output signal from the system exposed to water droplets from a garden hose can be rectified and harvested by a 33 μF capacitor, where the stored energy increases at a rate of about 20 μJ in 100 s.

  20. Compact hybrid cell based on a convoluted nanowire structure for harvesting solar and mechanical energy

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Chen; Wang, Zhong Lin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2011-02-15

    A fully integrated, solid-state, compact hybrid cell (CHC) that comprises ''convoluted'' ZnO nanowire structures for concurrent harvesting of both solar and mechanical energy is demonstrated. The compact hybrid cell is based on a conjunction design of an organic solid-state dye-sensitized solar cell (DSSC) and piezoelectric nanogenerator in one compact structure. The CHC shows a significant increase in output power, clearly demonstrating its potential for simultaneously harvesting multiple types of energy for powering small electronic devices for independent, sustainable, and mobile operation. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Rate of Dissipation of the Energy of Low-Frequency Mechanical Disturbances in a Tire

    Science.gov (United States)

    Grinchuk, P. S.; Fisenko, S. P.

    2016-11-01

    An expression for the rate of dissipation of the energy of low-frequency mechanical disturbances in a tire, accounting for the tired wheel radius, velocity of motion, and loading, has been derived. After processing experimental data on heating the tread rubber of an oversize tire by the proposed method, it has been revealed that about 30% of the energy of deformations appearing in motion of a loaded tire is converted into heat, and the coefficient of heat transfer between the tire and air has been derived.

  2. Energy Efficiency Investments in Public Facilities - Developing a Pilot Mechanism for Russia and Chelyabinsk Region

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Meredydd; Roshchanka, Volha; Parker, Steven A.; Baranovskiy, Aleksandr

    2012-01-01

    Russian public sector buildings tend to be very inefficient, which creates vast opportunities for savings. This paper reviews opportunities to implement energy efficiency projects in Russian public buildings, created by new Russian legislation and regulations. Given Russia's limited experience with energy performance contracts (EPCs), a pilot project can help test an implementation mechanism. The authors use Chelyabinsk Region as an example to discuss opportunities, challenges and solutions to financing and implementing an EPC in Russia, navigating through federal requirements and specific local conditions.

  3. Integrated environmental and safety assessment of selected mechanical energy storage systems

    Science.gov (United States)

    1982-01-01

    The environmental, safety, and social impacts of two mechanical storage systems, underground pumped hydro (UPH) and compressed air energy storage (CAES) are similar to those of existing peaking power plants. These impacts, with engineering factors, form a methodology for selecting sites for these two systems. Application of this methodology to a hypothetical case indicates that, although design alternatives which mitigate adverse environmental impacts are recommended, site selection effectively limits the environmental effect of CAES or UPH plants. Public perception of CAES and UPH energy storage facilities should generally be positive, provided that those affected are informed and allowed to participate in the siting process.

  4. Comparison of energy consumptions between ultrasonic, mechanical, and combined soil washing processes.

    Science.gov (United States)

    Son, Younggyu; Nam, Sanggeon; Ashokkumar, Muthupandian; Khim, Jeehyeong

    2012-05-01

    Vigorous physical effects including micro-jet and micro-streaming can be induced in heterogeneous systems by acoustic cavitation. This can be useful for the removal of pollutants from contaminated soil particles. In this study, the diesel removal efficiencies in ultrasonic, mechanical, and combined soil washing processes have been compared considering the electrical energy consumptions for these processes. The combined process showed synergistic effects for both removal efficiency and effective volume also has the advantage of a short operation time compared to the sequential processes. Thus the ultrasonic soil washing process with mechanical mixing is considered a promising technology for industrial use. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Harvesting wind energy to detect weak signals using mechanical stochastic resonance

    Science.gov (United States)

    Breen, Barbara J.; Rix, Jillian G.; Ross, Samuel J.; Yu, Yue; Lindner, John F.; Mathewson, Nathan; Wainwright, Elliot R.; Wilson, Ian

    2016-12-01

    Wind is free and ubiquitous and can be harnessed in multiple ways. We demonstrate mechanical stochastic resonance in a tabletop experiment in which wind energy is harvested to amplify weak periodic signals detected via the movement of an inverted pendulum. Unlike earlier mechanical stochastic resonance experiments, where noise was added via electrically driven vibrations, our broad-spectrum noise source is a single flapping flag. The regime of the experiment is readily accessible, with wind speeds ˜20 m/s and signal frequencies ˜1 Hz. We readily obtain signal-to-noise ratios on the order of 10 dB.

  6. Fulx-pinning mechanism and activation energy in malic acid-doped MgB2

    Directory of Open Access Journals (Sweden)

    SR Ghorbani

    2010-09-01

    Full Text Available Fulx-pinning mechanism and activation energy of MgB2 doped with 10 wt % malic- acid has been investigated by measurement of critical current density and resistivity as a function of magnetic fields and temperatures. The field dependence of the critical current density, Jc(B, was analyzed within the collective pinning model. A crossover field, Bsb, from the single vortex to the small vortex bundle-pinning regime was observed. For sintered sample, the temperature dependence of Bsb(T at low temperature is in good agreement with the δℓ pinning mechanism, i.e., pinning associated with charge-carrier mean free path fluctuation. The activation energy was decreased linearly by increasing magnetic field.

  7. Revealing the Mechanism of Low-Energy Electron Yield Enhancement from Sensitizing Nanoparticles

    CERN Document Server

    Verkhovtsev, Alexey V; Solov'yov, Andrey V

    2014-01-01

    We provide a physical explanation for enhancement of the low-energy electron production by sensitizing nanoparticles due to irradiation by fast ions. It is demonstrated that a significant increase in the number of emitted electrons arises from the collective electron excitations in the nanoparticle. We predict a new mechanism of the yield enhancement due to the plasmon excitations and quantitatively estimate its contribution to the electron production. Revealing the nanoscale mechanism of the electron yield enhancement, we provide an efficient tool for evaluating the yield of emitted electron from various sensitizers. It is shown that the number of low-energy electrons generated by the gold and platinum nanoparticles of a given size exceeds that produced by the equivalent volume of water and by other metallic (e.g., gadolinium) nanoparticles by an order of magnitude. This observation emphasizes the sensitization effect of the noble metal nanoparticles and endorses their application in novel technologies of ca...

  8. Scattering of inhomogeneous circularly polarized optical field and mechanical manifestation of the internal energy flows

    CERN Document Server

    Bekshaev, A Ya; Hanson, S G; Zenkova, C Yu

    2012-01-01

    Basing on the Mie theory and on the incident beam model via superposition of two plane waves, we analyze numerically the momentum flux of the field scattered by a spherical microparticle placed within the spatially inhomogeneous circularly polarized paraxial light beam. The asymmetry between the forward- and backward-scattered momentum fluxes in the Rayleigh scattering regime is revealed that appears due to the spin part of the internal energy flow in the incident beam. The transverse ponderomotive forces exerted on dielectric and conducting particles of different sizes are calculated, and special features of the mechanical actions produced by the spin and orbital parts of the internal energy flow have been recognized. In particular, the transverse orbital flow exerts on a subwavelength particle the transverse force that grows as a^3 for conducting and as a^6 for dielectric particle with radius a, in compliance with the dipole mechanism of the field-particle interaction; the force associated with the spin flo...

  9. Description of the performances of a thermo-mechanical energy harvester using bimetallic beams

    Science.gov (United States)

    Arnaud, A.; Boughaleb, J.; Monfray, S.; Boeuf, F.; Cugat, O.; Skotnicki, T.

    2016-06-01

    Many recent researches have been focused on the development of thermal energy harvesters using thermo-mechanical or thermo-electrical coupling phenomena associated to a first-order thermodynamic transition. In the case of the bimetallic strip heat engine, the exploitation of the thermo-mechanical instability of bimetallic membranes placed in a thermal gradient enables to convert heat into kinetic energy. This paper is a contribution to the modeling and the comprehension of these heat engines. By restraining the study to the simply-supported bimetallic beams and using a Ritz approximation of the beam shape, this paper aims to give an analytical solution to the first mode of the composite beams and then to evaluate the efficiency of the harvesters exploiting these kinds of instability.

  10. Dynamic Modeling and Control of Electromechanical Coupling for Mechanical Elastic Energy Storage System

    Directory of Open Access Journals (Sweden)

    Yang Yu

    2013-01-01

    Full Text Available The structural scheme of mechanical elastic energy storage (MEES system served by permanent magnet synchronous motor (PMSM and bidirectional converters is designed. The aim of the research is to model and control the complex electromechanical system. The mechanical device of the complex system is considered as a node in generalized coordinate system, the terse nonlinear dynamic model of electromechanical coupling for the electromechanical system is constructed through Lagrange-Maxwell energy method, and the detailed deduction of the mathematical model is presented in the paper. The theory of direct feedback linearization (DFL is applied to decouple the nonlinear dynamic model and convert the developed model from nonlinear to linear. The optimal control theory is utilized to accomplish speed tracking control for the linearized system. The simulation results in three different cases show that the proposed nonlinear dynamic model of MEES system is correct; the designed algorithm has a better control performance in contrast with the conventional PI control.

  11. Azole energetic materials: initial mechanisms for the energy release from electronical excited nitropyrazoles.

    Science.gov (United States)

    Yuan, Bing; Yu, Zijun; Bernstein, Elliot R

    2014-01-21

    Decomposition of energetic material 3,4-dinitropyrazole (DNP) and two model molecules 4-nitropyrazole and 1-nitropyrazole is investigated both theoretically and experimentally. The initial decomposition mechanisms for these three nitropyrazoles are explored with complete active space self-consistent field (CASSCF) level. The NO molecule is observed as an initial decomposition product from all three materials subsequent to UV excitation. Observed NO products are rotationally cold (energetic material DNP, NO is produced on the ground state surface, as the S1 decomposition pathway is energetically unavailable. The theoretically predicted mechanism is consistent with the experimental results, as DNP decomposes in a lower electronic state than do the model systems and thus the vibrational energy in the NO product from DNP should be hotter than from the model systems. The observed rotational energy distributions for NO are consistent with the final structures of the respective transition states for each molecule.

  12. Innovative Energy Harvester Design Using Bistable Mechanism With Compensational Springs In Gravity Field

    Science.gov (United States)

    Vysotskyi, Bogdan; Parrain, Fabien; Aubry, Denis; Gaucher, Philippe; Lefeuvre, Elie

    2016-11-01

    The purpose of the presented work is to introduce the novel design of electrostatic energy harvester using bistable mechanism with compensational springs in gravity field capable of providing the output of several μW under the excitation of extremely small amplitude (up to 0.2g) and low frequency (10-100Hz). Presented energy harvester uses the bistable hysteresis modification to achieve low-frequency low-amplitude sensibility. It was demonstrated with finite element modelling (FEM) that hysteresis width produced by bistability is changing with a constant linear coefficient as a function of a compensational spring stiffness and thus a device sensitivity could be adjusted to the minimum point for the amplitude of external excitation. Further, highly non-linear bistable double curved beam mechanism assures the high sensitivity in frequencial domain due to the non-defined bandwidth. The equivalent circuit technique is used for simulating the device performance.

  13. Energy Drinks and Their Impact on the Cardiovascular System: Potential Mechanisms.

    Science.gov (United States)

    Grasser, Erik Konrad; Miles-Chan, Jennifer Lynn; Charrière, Nathalie; Loonam, Cathríona R; Dulloo, Abdul G; Montani, Jean-Pierre

    2016-09-01

    Globally, the popularity of energy drinks is steadily increasing. Scientific interest in their effects on cardiovascular and cerebrovascular systems in humans is also expanding and with it comes a growing number of case reports of adverse events associated with energy drinks. The vast majority of studies carried out in the general population report effects on blood pressure and heart rate. However, inconsistencies in the current literature render it difficult to draw firm conclusions with regard to the effects of energy drinks on cardiovascular and cerebrovascular variables. These inconsistencies are due, in part, to differences in methodologies, volume of drink ingested, and duration of postconsumption measurements, as well as subject variables during the test. Recent well-controlled, randomized crossover studies that used continuous beat-to-beat measurements provide evidence that cardiovascular responses to the ingestion of energy drinks are best explained by the actions of caffeine and sugar, with little influence from other ingredients. However, a role for other active constituents, such as taurine and glucuronolactone, cannot be ruled out. This article reviews the potentially adverse hemodynamic effects of energy drinks, particularly on blood pressure and heart rate, and discusses the mechanisms by which their active ingredients may interact to adversely affect the cardiovascular system. Research areas and gaps in the literature are discussed with particular reference to the use of energy drinks among high-risk individuals.

  14. Fermilab Central Computing Facility: Energy conservation report and mechanical systems design optimization and cost analysis study

    Energy Technology Data Exchange (ETDEWEB)

    Krstulovich, S.F.

    1986-11-12

    This report is developed as part of the Fermilab Central Computing Facility Project Title II Design Documentation Update under the provisions of DOE Document 6430.1, Chapter XIII-21, Section 14, paragraph a. As such, it concentrates primarily on HVAC mechanical systems design optimization and cost analysis and should be considered as a supplement to the Title I Design Report date March 1986 wherein energy related issues are discussed pertaining to building envelope and orientation as well as electrical systems design.

  15. Production mechanism of hot nuclei in violent collisions in the Fermi energy domain

    OpenAIRE

    Veselsky, M.

    2001-01-01

    A production mechanism of highly excited nuclei formed in violent collisions in the Fermi energy domain is investigated. The collision of two nuclei is decomposed into several stages which are treated separately. Simplified exciton concept is used for the description of pre-equilibrium emission. A modified spectator-participant scenario is used where motion along classical Coulomb trajectories is assumed. The participant and one of the spectator zones undergo incomplete fusion. Excitation ene...

  16. Macroscopic momentum and mechanical energy equations for incompressible single-phase flow in porous media

    Science.gov (United States)

    Paéz-García, Catherine Teresa; Valdés-Parada, Francisco J.; Lasseux, Didier

    2017-02-01

    Modeling flow in porous media is usually focused on the governing equations for mass and momentum transport, which yield the velocity and pressure at the pore or Darcy scales. However, in many applications, it is important to determine the work (or power) needed to induce flow in porous media, and this can be achieved when the mechanical energy equation is taken into account. At the macroscopic scale, this equation may be postulated to be the result of the inner product of Darcy's law and the seepage velocity. However, near the porous medium boundaries, this postulate seems questionable due to the spatial variations of the effective properties (velocity, permeability, porosity, etc.). In this work we derive the macroscopic mechanical energy equation using the method of volume averaging for the simple case of incompressible single-phase flow in porous media. Our analysis shows that the result of averaging the pore-scale version of the mechanical energy equation at the Darcy scale is not, in general, the expected product of Darcy's law and the seepage velocity. As a matter of fact, this result is only applicable in the bulk region of the porous medium and, in the derivation of this result, the properties of the permeability tensor are determinant. Furthermore, near the porous medium boundaries, a more novel version of the mechanical energy equation is obtained, which incorporates additional terms that take into account the rapid variations of structural properties taking place in this particular portion of the system. This analysis can be applied to multiphase and compressible flows in porous media and in many other multiscale systems.

  17. Reaction mechanism study of 7Li(7Li, 6He) reaction at above Coulomb barrier energies

    Indian Academy of Sciences (India)

    V V Parkar; V Jha; S Santra; B J Roy; K Ramachandran; A Shrivastava; K Mahata; A Chatterjee; S Kailas

    2009-02-01

    The elastic scattering and the 6He angular distributions were measured in 7Li + 7Li reaction at two energies, lab = 20 and 25 MeV. FRDWBA calculations have been performed to explain the measured 6He data. The calculations were very sensitive to the choice of the optical model potentials in entrance and exit channels. The one-step proton transfer was found to be the dominant reaction mechanism in 6He production.

  18. The energy saving potential of a new mechanical pulping process; Puristushieronnan mahdollisuudet mekaanisen massanvalmistuksen energiakulutuksen pienentaemisessae

    Energy Technology Data Exchange (ETDEWEB)

    Pietarila, V. (UPM-Kymmene OYj, Lappeenranta (Finland))

    2008-07-01

    The target of this project is to develop a new mechanical pulping process to produce papermaking pulp from chips. Energy consumption of this process should be remarkably lower than in mill processes today. In earlier small scale studies it has been pointed out that it could be possible to produce acceptable pulp in a process that differs from todayAEs pulp production methods. Anyhow extensive research efforts are required to test and develop this new process. (orig.)

  19. Exploring the mechanism(s) of energy dissipation in the light harvesting complex of the photosynthetic algae Cyclotella meneghiniana.

    Science.gov (United States)

    Ramanan, Charusheela; Berera, Rudi; Gundermann, Kathi; van Stokkum, Ivo; Büchel, Claudia; van Grondelle, Rienk

    2014-09-01

    Photosynthetic organisms have developed vital strategies which allow them to switch from a light-harvesting to an energy dissipative state at the level of the antenna system in order to survive the detrimental effects of excess light illumination. These mechanisms are particularly relevant in diatoms, which grow in highly fluctuating light environments and thus require fast and strong response to changing light conditions. We performed transient absorption spectroscopy on FCPa, the main light-harvesting antenna from the diatom Cyclotella meneghiniana, in the unquenched and quenched state. Our results show that in quenched FCPa two quenching channels are active and are characterized by differing rate constants and distinct spectroscopic signatures. One channel is associated with a faster quenching rate (16ns⁻¹) and virtually no difference in spectral shape compared to the bulk unquenched chlorophylls, while a second channel is associated with a slower quenching rate (2.7ns⁻¹) and exhibits an increased population of red-emitting states. We discuss the origin of the two processes in the context of the models proposed for the regulation of photosynthetic light-harvesting. This article is part of a special issue entitled: photosynthesis research for sustainability: keys to produce clean energy.

  20. Impact of Residential Mechanical Ventilation on Energy Cost and Humidity Control

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Eric [Building Science Corporation, Westford, MA (United States)

    2014-01-01

    Optimizing whole house mechanical ventilation as part of the Building Ameerica program's systems engineered approach to constructing housing has been an important subject of the program's research. Ventilation in residential buildings is one component of an effective, comprehensive strategy for creation and maintenance of a comfortable and healthy indoor air environment. The study described in this report is based on building energy modeling with an important focus on the indoor humidity impacts of ventilation. The modeling tools used were EnergyPlus version 7.1 (E+) and EnergyGauge USA (EGUSA). Twelve U.S. cities and five climate zones were represented. A total of 864 simulations (2*2*3*3*12= 864) were run using two building archetypes, two building leakage rates, two building orientations, three ventilation systems, three ventilation rates, and twelve climates.

  1. Effects of laser pulse energy on surface microstructure and mechanical properties of high carbon steel

    Institute of Scientific and Technical Information of China (English)

    熊毅; 贺甜甜; 李鹏燕; 陈路飞; 任凤章; Alex A. Volinsky

    2015-01-01

    Surface microstructure and mechanical properties of pearlitic Fe–0.8%C (mass fraction) steel after laser shock processing (LSP) with different laser pulse energies were investigated by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD) and microhardness measurements. After LSP, the cementite lamellae were bent, kinked and broken into particles. Fragmentation and dissolution of the cementite lamellae were enhanced by increasing the laser pulse energy. Due to the dissolution of carbon atoms in the ferritic matrix, the lattice parameter ofα-Fe increased. The grain size of the surface ferrite was refined, and the microstructure changed from lamellae to ultrafine micro-duplex structure (ferrite (α)+cementite (θ)) with higher laser pulse energy, accompanied by the residual stress and microhardness increase.

  2. Thermo-mechanical Analysis of the CLIC Post-Linac Energy Collimators

    CERN Document Server

    Resta-Lopez, J; Latina, A

    2012-01-01

    The post-linac energy collimation system of the Compact Linear Collider (CLIC) has been designed for passive protection of the Beam Delivery System (BDS) against miss-steered beams due to failure modes in the main linac. In this paper, a thermo-mechanical analysis of the CLIC energy collimators is presented. This study is based on simulations using the codes FLUKA and ANSYS when an entire bunch train hits the collimators. Different failure mode scenarios in the main linac are considered. The aim is to improve the collimator in order to make a reliable and robust design so that survives without damage the impact of a full bunch train in case of likely events generating energy errors.

  3. Production mechanism of hot nuclei in violent collisions in the Fermi energy domain

    CERN Document Server

    Veselsky, M

    2002-01-01

    A production mechanism of highly excited nuclei formed in violent collisions in the Fermi energy domain is investigated. Collision of two nuclei is decomposed into several stages which are treated separately. A simple phenomenological approach based on the exciton concept is used for the description of pre-equilibrium emission. For violent collisions, a modified spectator-participant scenario is used where relative motion along the classical Coulomb trajectories is assumed. A simple approach is used for description of the incomplete fusion of the participant and one of the spectator zones. Excitation energies of both fragments are determined. Results of the calculation are compared to wide range of recent experimental nuclear reaction data in the Fermi energy domain. Geometric aspects of pre-equilibrium emission are revealed. Properties of hot projectile-like, mid-velocity and fusion-like sources are discussed. An adequate overall agreement between experiment and calculation is obtained.

  4. Renewable Energy Investment in Emerging Markets: Evaluating Improvements to the Clean Development Mechanism

    Directory of Open Access Journals (Sweden)

    Amy Tang

    2014-06-01

    Full Text Available In the past, industrialized countries have invested in or financed numerous renewable energy projects in developing countries, primarily through the Clean Development Mechanism (CDM of the Kyoto Protocol. However, critics have pointed to its bureaucratic structure, problems with additionality and distorted credit prices as ill-equipped to streamline renewable energy investment. In this paper, we simulate the impact of policy on investment decisions on whether or not to invest in wind energy infrastructure in India, Brazil and China. Data from 2,578 past projects as well as literature on investor behaviour is used to inform the model structure and parameters. Our results show that the CDM acts differently in each country and reveal that while streamlining the approval process and reconsidering additionality can lead to non-trivial increase in total investment, stabilizing policy and decreasing investment risk will do the most to spur investment.

  5. Using Robotic Fish to Explore the Hydrodynamic Mechanism of Energy Saving in a Fish School

    CERN Document Server

    Li, Liang; Xie, Guangming

    2015-01-01

    Fish often travel in highly organized schools. One of the most quoted functions of these configurations is energy savings. Here, we verified the hypothesis and explored the mechanism through series of experiments on "schooling" robotic fish, which can undulate actively with flexible body, resembling real fish. We find that, when the school swims in the same spatial arrays as the real one, the energy consumption of the follower mainly depends on the phase difference, a phase angle by which the body wave of the follower leads or lags that of the leader, instead of spatial arrays. Further analysis through flow visualization indicates that the follower saves energy when the phase difference corresponds to the situation that the follower flaps in the same direction of the flow field induced by the vortex dipole shedding by the leader. Using biomimetic robots to verify the biological hypothesis in this paper also sheds new light on the connections among the fields of engineering, physics and biology.

  6. Breakup mechanisms for 7Li + 197Au, 204Pb systems at sub-barrier energies

    Directory of Open Access Journals (Sweden)

    Luong D.H.

    2013-12-01

    Full Text Available Coincidence measurements of breakup fragments were carried out for the 7Li + 197Au and 204Pb systems at sub-barrier energies. The mechanisms triggering breakup, and time-scales of each process, were identified through the reaction Q-values and the relative energy of the breakup fragments. Binary breakup of 7Li were found to be predominantly triggered by nucleon transfer, with p-pickup leading to 8Be → α + α decay being the preferred breakup mode. From the time-scales of each process, the coincidence yields were separated into prompt and delayed components, allowing the identification of breakup process important in the suppression of complete fusion of 7Li at above-barrier energies.

  7. Interference-Aware Opportunistic Dynamic Energy Saving Mechanism for Wi-Fi Enabled IoTs

    Directory of Open Access Journals (Sweden)

    Il-Gu Lee

    2017-07-01

    Full Text Available The wireless local area network (WLAN is one of the most popular wireless technologies offering connectivity today, and one of the candidates for the internet of things (IoTs. However, WLAN’s inefficiency in terms of complexity and relatively large power consumption compared with other wireless standards has been reported as a major barrier for IoTs applications. This paper proposes an interference-aware opportunistic dynamic energy saving mechanism to improve energy efficiency for Wi-Fi enabled IoTs. The proposed scheme optimizes operating clock frequencies adaptively for signal processing when the mobile station transmits packets in partial sub-channels. Evaluation results demonstrate that the proposed scheme improves energy efficiency by approximately 34%.

  8. High-efficiency piezoelectric micro harvester for collecting low-frequency mechanical energy

    Science.gov (United States)

    Li, Xin; Song, Jinhui; Feng, Shuanglong; Xie, Xiong; Li, Zhenhu; Wang, Liang; Pu, Yayun; Kah Soh, Ai; Shen, Jun; Lu, Wenqiang; Liu, Shuangyi

    2016-12-01

    A single-layer zinc oxide (ZnO) nanorod array-based micro energy harvester was designed and integrated with a piezoelectric metacapacitor. The device presents outstanding low-frequency (1-10 Hz) mechanical energy harvesting capabilities. When compared with conventional pristine ZnO nanostructured piezoelectric harvesters or generators, both open-circuit potential and short-circuit current are significantly enhanced (up to 3.1 V and 124 nA cm-2) for a single mechanical knock (˜34 kPa). Higher electromechanical conversion efficiency (1.3 pC/Pa) is also observed. The results indicate that the integration of the piezoelectric metacapacitor is a crucial factor for improving the low-frequency energy harvesting performance. A double piezoelectric-driven mechanism is proposed to explain current higher output power, in which the metacapacitor plays the multiple roles of charge pumping, storing and transferring. An as-fabricated prototype device for lighting an LED demonstrates high power transference capability, with over 95% transference efficiency to the external load.

  9. Energy Dissipation in Graphene Mechanical Resonators with and without Free Edges

    Directory of Open Access Journals (Sweden)

    Makoto Takamura

    2016-09-01

    Full Text Available Graphene-based nanoelectromechanical systems (NEMS have high future potential to realize sensitive mass and force sensors owing to graphene’s low mass density and exceptional mechanical properties. One of the important remaining issues in this field is how to achieve mechanical resonators with a high quality factor (Q. Energy dissipation in resonators decreases Q, and suppressing it is the key to realizing sensitive sensors. In this article, we review our recent work on energy dissipation in doubly-clamped and circular drumhead graphene resonators. We examined the temperature (T dependence of the inverse of a quality factor ( Q - 1 to reveal what the dominant dissipation mechanism is. Our doubly-clamped trilayer resonators show a characteristic Q - 1 -T curve similar to that observed in monolayer resonators: Q - 1 ∝ T 2 above ∼100 K and ∝ T 0.3 below ∼100 K. By comparing our results with previous experimental and theoretical results, we determine that the T 2 and T 0.3 dependences can be attributed to tensile strain induced by clamping metals and vibrations at the free edges in doubly-clamped resonators, respectively. The Q - 1 -T curve in our circular drumhead resonators indicates that removing free edges and clamping metal suppresses energy dissipation in the resonators, resulting in a linear T dependence of Q - 1 in a wide temperature range.

  10. Electricity Generation Characteristics of Energy-Harvesting System with Piezoelectric Element Using Mechanical-Acoustic Coupling

    Directory of Open Access Journals (Sweden)

    Hirotarou Tsuchiya

    2016-01-01

    Full Text Available This paper describes the electricity generation characteristics of a new energy-harvesting system with piezoelectric elements. The proposed system is composed of a rigid cylinder and thin plates at both ends. The piezoelectric elements are installed at the centers of both plates, and one side of each plate is subjected to a harmonic point force. In this system, vibration energy is converted into electrical energy via electromechanical coupling between the plate vibration and piezoelectric effect. In addition, the plate vibration excited by the point force induces a self-sustained vibration at the other plate via mechanical-acoustic coupling between the plate vibrations and an internal sound field into the cylindrical enclosure. Therefore, the electricity generation characteristics should be considered as an electromechanical-acoustic coupling problem. The characteristics are estimated theoretically and experimentally from the electric power in the electricity generation, the mechanical power supplied to the plate, and the electricity generation efficiency that is derived from the ratio of both power. In particular, the electricity generation efficiency is one of the most appropriate factors to evaluate a performance of electricity generation systems. Thus, the effect of mechanical-acoustic coupling is principally evaluated by examining the electricity generation efficiency.

  11. Tribo-Mechanical Investigation of the Functional Components used in Flexible Energy Harvesting Devices

    Science.gov (United States)

    Morris, Nicholas J.

    During the previous decade, the development of energy harvesting devices based on piezoelectric materials has garnered great interest. The ability to capture ambient mechanical energy and convert it to useable electricity is a potential solution to the ever-growing energy crisis. One of the most attractive functional materials used in these devices is zinc oxide (ZnO). This material's relative low cost and ease of large-area processing has spurred numerous device designs based around it. The ability to grow ZnO nanostructures of various geometries with low-temperature chemical methods makes this material even more attractive for flexible devices. Although numerous device architectures have been developed, the long-term mechanical reliability has not been addressed. This work focuses on the fabrication and mechanical failure analysis of the flexible components typically used in piezoelectric energy harvesting devices. A three-phase iterative design process was used to fabricate prototypical piezoelectric nanogenerators, based on ZnO nanowires. An output of several millivolts was achieved under normal contact and microtensile loading, but device failure occurred after only a few loading cycles, in all cases. Ex situ failure analysis confirmed the primary sources of failure, which became the focus of further, component-level studies. Failure was primarily seen in the flexible electrodes of the nanogenerating devices, but was also observed in the functional piezoelectric layer itself. Flexible electrodes comprised of polyester substrates with transparent conductive oxide (TCO) coatings were extensively investigated under various loading scenarios to mimic tribo-mechanical stresses applied during fabrication and use in flexible contact-based devices. The durability of these films was explored using microtensile testing, spherical nanoindentation, controlled mechanical buckling, stress corrosion cracking, and shear-contact reciprocating wear. The electro-mechanical

  12. A Novel Tunable Multi-Frequency Hybrid Vibration Energy Harvester Using Piezoelectric and Electromagnetic Conversion Mechanisms

    Directory of Open Access Journals (Sweden)

    Zhenlong Xu

    2016-01-01

    Full Text Available This paper presents a novel tunable multi-frequency hybrid energy harvester (HEH. It consists of a piezoelectric energy harvester (PEH and an electromagnetic energy harvester (EMEH, which are coupled with magnetic interaction. An electromechanical coupling model was developed and numerically simulated. The effects of magnetic force, mass ratio, stiffness ratio, and mechanical damping ratios on the output power were investigated. A prototype was fabricated and characterized by experiments. The measured first peak power increases by 16.7% and 833.3% compared with that of the multi-frequency EMEH and the multi-frequency PEH, respectively. It is 2.36 times more than the combined output power of the linear PEH and linear EMEH at 22.6 Hz. The half-power bandwidth for the first peak power is also broadened. Numerical results agree well with the experimental data. It is indicated that magnetic interaction can tune the resonant frequencies. Both magnetic coupling configuration and hybrid conversion mechanism contribute to enhancing the output power and widening the operation bandwidth. The magnitude and direction of magnetic force have significant effects on the performance of the HEH. This proposed HEH is an effective approach to improve the generating performance of the micro-scale energy harvesting devices in low-frequency range.

  13. Analysis of Mechanical Energy Transport on Free-Falling Wedge during Water-Entry Phase

    Directory of Open Access Journals (Sweden)

    Wen-Hua Wang

    2012-01-01

    Full Text Available For better discussing and understanding the physical phenomena and body-fluid interaction of water-entry problem, here mechanical-energy transport (wedge, fluid, and each other of water-entry model for free falling wedge is studied by numerical method based on free surface capturing method and Cartesian cut cell mesh. In this method, incompressible Euler equations for a variable density fluid are numerically calculated by the finite volume method. Then artificial compressibility method, dual-time stepping technique, and Roe's approximate Riemann solver are applied in the numerical scheme. Furthermore, the projection method of momentum equations and exact Riemann solution are used to calculate the fluid pressure on solid boundary. On this basis, during water-entry phase of the free-falling wedge, macroscopic energy conversion of overall body-fluid system and microscopic energy transformation in fluid field are analyzed and discussed. Finally, based on test cases, many useful conclusions about mechanical energy transport for water entry problem are made and presented.

  14. Floating Oscillator-Embedded Triboelectric Generator for Versatile Mechanical Energy Harvesting

    Science.gov (United States)

    Seol, Myeong-Lok; Han, Jin-Woo; Jeon, Seung-Bae; Meyyappan, M.; Choi, Yang-Kyu

    2015-01-01

    A versatile vibration energy harvesting platform based on a triboelectricity is proposed and analyzed. External mechanical vibration repeats an oscillating motion of a polymer-coated metal oscillator floating inside a surrounding tube. Continuous sidewall friction at the contact interface of the oscillator induces current between the inner oscillator electrode and the outer tube electrode to convert mechanical vibrations into electrical energy. The floating oscillator-embedded triboelectric generator (FO-TEG) is applicable for both impulse excitation and sinusoidal vibration which universally exist in usual environment. For the impulse excitation, the generated current sustains and slowly decays by the residual oscillation of the floating oscillator. For the sinusoidal vibration, the output energy can be maximized by resonance oscillation. The operating frequency range can be simply optimized with high degree of freedom to satisfy various application requirements. In addition, the excellent immunity against ambient humidity is experimentally demonstrated, which stems from the inherently packaged structure of FO-TEG. The prototype device provides a peak-to-peak open-circuit voltage of 157 V and instantaneous short-circuit current of 4.6 μA, within sub-10 Hz of operating frequency. To visually demonstrate the energy harvesting behavior of FO-TEG, lighting of an array of LEDs is demonstrated using artificial vibration and human running. PMID:26553524

  15. Mechanics of cuticular elastic energy storage in leg joints lacking extensor muscles in arachnids.

    Science.gov (United States)

    Sensenig, Andrew T; Shultz, Jeffrey W

    2003-02-01

    Certain leg joints in arachnids lack extensor muscles and have elastically deformable transarticular sclerites spanning their arthrodial membranes, an arrangement consistent with a model in which flexor muscles load transarticular sclerites during flexion and energy from elastic recoil is used for extension. This study quantifies the potential contribution of elastic recoil to extension torque at joints of the fourth leg of representative arachnids. Extension torques of isolated joints with and without transarticular sclerites were measured as the joint was rotated through angles and at angular velocities comparable with those used by walking animals. The procedure was repeated with the joint subjected to different internal fluid pressures in order to assess the potential role of hydraulically induced extension. The efficiency of elastic energy storage (resilience) in the absence of internal fluid pressure was 70-90% for joints with well-developed transarticular sclerites, and the magnitude of torque was similar to those produced by different joint extension mechanisms in other arthropods. Increased internal fluid pressure acted synergistically with transarticular sclerites in some joints but had little or no effect in others. Joints that lacked both extensor muscles and transarticular sclerites appeared to be specialized for hydraulic extension, and joints operated by antagonistic muscles lacked apparent specializations for either elastic or hydraulic extension. It is well known that elastic energy storage is a significant contributor to propulsion in running vertebrates and certain arthropods, where elastic elements are loaded as the center of mass falls during one phase of the locomotor cycle. However, transarticular sclerites are apparently loaded by contraction of flexor muscles when the leg is not in contact with the substratum. Hence the mechanism of a transarticular sclerite is more similar to the flight and jumping mechanisms of other arthropods than to

  16. Harvesting broadband kinetic impact energy from mechanical triggering/vibration and water waves.

    Science.gov (United States)

    Wen, Xiaonan; Yang, Weiqing; Jing, Qingshen; Wang, Zhong Lin

    2014-07-22

    We invented a triboelectric nanogenerator (TENG) that is based on a wavy-structured Cu-Kapton-Cu film sandwiched between two flat nanostructured PTFE films for harvesting energy due to mechanical vibration/impacting/compressing using the triboelectrification effect. This structure design allows the TENG to be self-restorable after impact without the use of extra springs and converts direct impact into lateral sliding, which is proved to be a much more efficient friction mode for energy harvesting. The working mechanism has been elaborated using the capacitor model and finite-element simulation. Vibrational energy from 5 to 500 Hz has been harvested, and the generator's resonance frequency was determined to be ∼100 Hz at a broad full width at half-maximum of over 100 Hz, producing an open-circuit voltage of up to 72 V, a short-circuit current of up to 32 μA, and a peak power density of 0.4 W/m(2). Most importantly, the wavy structure of the TENG can be easily packaged for harvesting the impact energy from water waves, clearly establishing the principle for ocean wave energy harvesting. Considering the advantages of TENGs, such as cost-effectiveness, light weight, and easy scalability, this approach might open the possibility for obtaining green and sustainable energy from the ocean using nanostructured materials. Lastly, different ways of agitating water were studied to trigger the packaged TENG. By analyzing the output signals and their corresponding fast Fourier transform spectra, three ways of agitation were evidently distinguished from each other, demonstrating the potential of the TENG for hydrological analysis.

  17. ForceFit: a code to fit classical force fields to quantum mechanical potential energy surfaces.

    Science.gov (United States)

    Waldher, Benjamin; Kuta, Jadwiga; Chen, Samuel; Henson, Neil; Clark, Aurora E

    2010-09-01

    The ForceFit program package has been developed for fitting classical force field parameters based upon a force matching algorithm to quantum mechanical gradients of configurations that span the potential energy surface of the system. The program, which runs under UNIX and is written in C++, is an easy-to-use, nonproprietary platform that enables gradient fitting of a wide variety of functional force field forms to quantum mechanical information obtained from an array of common electronic structure codes. All aspects of the fitting process are run from a graphical user interface, from the parsing of quantum mechanical data, assembling of a potential energy surface database, setting the force field, and variables to be optimized, choosing a molecular mechanics code for comparison to the reference data, and finally, the initiation of a least squares minimization algorithm. Furthermore, the code is based on a modular templated code design that enables the facile addition of new functionality to the program. Copyright 2010 Wiley Periodicals, Inc.

  18. Discerning the catalytic mechanism of Staphylococcus aureus sortase A with QM/MM free energy calculations.

    Science.gov (United States)

    Shrestha, Pooja; Wereszczynski, Jeff

    2016-06-01

    Sortases are key virulence factors in Gram-positive bacteria. These enzymes embed surface proteins in the cell wall through a transpeptidation reaction that involves recognizing a penta-peptide "sorting signal" in a target protein, cleaving it, and covalently attaching it to a second substrate that is later inserted into the cell wall. Although well studied, several aspects of the mechanism by which sortases perform these functions remains unclear. In particular, experiments have revealed two potential sorting signal binding motifs: a "Threonine-Out" (Thr-Out) structure in which the catalytically critical threonine residues protrudes into solution, and a "Threonine-In" (Thr-In) configuration in which this residue inserts into the binding site. To determine which of these is the biologically relevant state, we have performed a series of conventional and hybrid quantum mechanics/molecular mechanics (QM/MM) molecular dynamics simulations of the Staphylococcus aureus sortase A (SrtA) enzyme bound to a sorting signal substrate. Through the use of multi-dimensional metadynamics, our simulations were able to both map the acylation mechanism of SrtA in the Thr-In and Thr-Out states, as well as determine the free energy minima and barriers along these reactions. Results indicate that in both states the catalytic mechanisms are similar, however the free energy barriers are lower in the Thr-In configuration, suggesting that Thr-In is the catalytically relevant state. This has important implications for advancing our understanding of the mechanisms of sortase enzymes, as well we for future structure based drug design efforts aimed at inhibiting sortase function in vivo.

  19. Cooperation mechanisms of the EU renewable energy directive and flexible mechanisms of the Kyoto Protocol: comparison and lessons learnt. Working paper

    Energy Technology Data Exchange (ETDEWEB)

    Frieden, Dorian; Tuerk, Andreas; Steiner, Daniel

    2013-07-15

    This working paper discusses similarities and differences between the cooperation mechanisms of the EU renewable energy directive (RES directive) and the flexible mechanisms of the Kyoto Protocol. The cooperation mechanisms allow the (virtual) trade of renewable energy and were introduced with the RES directive to provide Member States (MS) with greater flexibility to achieve their national targets for renewable energy sources (RES). A similar kind of flexibility is known from the flexible mechanisms of the Kyoto Protocol which aim at the cost efficient achievement of emission reduction targets. Lessons learned from the Kyoto mechanisms may allow conclusions to be drawn on the design and implementation of the renewable energy cooperation mechanisms. This paper first gives an overview of the cooperation mechanisms regarding their potential, advantages and disadvantages, barriers and preconditions. This is followed by a brief explanation of and a systematic comparison with the flexible mechanisms of the Kyoto Protocol – Joint Implementation (JI); Clean Development Mechanism (CDM); and International Emissions Trading (IET). A gamut of factors influenced the success of the Kyoto mechanisms in general and in specific national contexts. Therefore, it is not possible to directly transfer past experiences with the Kyoto mechanisms to the capability of specific nations to make use of the renewable energy cooperation mechanisms. A comparison of specific features, such as the mechanism type (transfer, project-based, support scheme), price building and specific barriers can, however, help anticipate the possible dynamics and challenges of the cooperation mechanisms. Experiences with the Kyoto mechanisms show that predictions based on supply-demand analysis were valid only to a limited extent and that specific factors such as institutional capacity constraints or legal uncertainties delayed or prevented the use of the mechanisms in some cases. Similarly, for the cooperation

  20. Quantum mechanical electronic structure calculation reveals orientation dependence of hydrogen bond energy in proteins.

    Science.gov (United States)

    Mondal, Abhisek; Datta, Saumen

    2017-06-01

    Hydrogen bond plays a unique role in governing macromolecular interactions with exquisite specificity. These interactions govern the fundamental biological processes like protein folding, enzymatic catalysis, molecular recognition. Despite extensive research work, till date there is no proper report available about the hydrogen bond's energy surface with respect to its geometric parameters, directly derived from proteins. Herein, we have deciphered the potential energy landscape of hydrogen bond directly from the macromolecular coordinates obtained from Protein Data Bank using quantum mechanical electronic structure calculations. The findings unravel the hydrogen bonding energies of proteins in parametric space. These data can be used to understand the energies of such directional interactions involved in biological molecules. Quantitative characterization has also been performed using Shannon entropic calculations for atoms participating in hydrogen bond. Collectively, our results constitute an improved way of understanding hydrogen bond energies in case of proteins and complement the knowledge-based potential. Proteins 2017; 85:1046-1055. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  1. Molecular mechanism of polyacrylate helix sense switching across its free energy landscape.

    Science.gov (United States)

    Pietropaolo, Adriana; Nakano, Tamaki

    2013-04-17

    Helical polymers with switchable screw sense are versatile frameworks for chiral functional materials. In this work, we reconstructed the free energy landscape of helical poly(2,7-bis(4-tert-butylphenyl)fluoren-9-yl acrylate) [poly(BBPFA)], as its racemization is selectively driven by light without any rearrangement of chemical bonds. The chirality inversion was enforced by atomistic free energy simulations using chirality indices as reaction coordinates. The free energy landscape reproduced the experimental electronic circular dichroism spectra. We propose that the chirality inversion of poly(BBPFA) proceeds from a left-handed 31 helix via multistate free energy pathways to reach the right-handed 31 helix. The inversion is triggered by the rotation of biphenyl units with an activation barrier of 38 kcal/mol. To the best of our knowledge, this is the first report on the chiral inversion mechanism of a helical polymer determined in a quantitative way in the framework of atomistic free energy simulations.

  2. Measuring the energy landscape roughness and the transition state location of biomolecules using single molecule mechanical unfolding experiments

    OpenAIRE

    2006-01-01

    Single molecule mechanical unfolding experiments are beginning to provide profiles of the complex energy landscape of biomolecules. In order to obtain reliable estimates of the energy landscape characteristics it is necessary to combine the experimental measurements with sound theoretical models and simulations. Here, we show how by using temperature as a variable in mechanical unfolding of biomolecules in laser optical tweezer or AFM experiments the roughness of the energy landscape can be m...

  3. Identification of a mechanism of photoprotective energy dissipation in higher plants.

    Science.gov (United States)

    Ruban, Alexander V; Berera, Rudi; Ilioaia, Cristian; van Stokkum, Ivo H M; Kennis, John T M; Pascal, Andrew A; van Amerongen, Herbert; Robert, Bruno; Horton, Peter; van Grondelle, Rienk

    2007-11-22

    Under conditions of excess sunlight the efficient light-harvesting antenna found in the chloroplast membranes of plants is rapidly and reversibly switched into a photoprotected quenched state in which potentially harmful absorbed energy is dissipated as heat, a process measured as the non-photochemical quenching of chlorophyll fluorescence or qE. Although the biological significance of qE is established, the molecular mechanisms involved are not. LHCII, the main light-harvesting complex, has an inbuilt capability to undergo transformation into a dissipative state by conformational change and it was suggested that this provides a molecular basis for qE, but it is not known if such events occur in vivo or how energy is dissipated in this state. The transition into the dissipative state is associated with a twist in the configuration of the LHCII-bound carotenoid neoxanthin, identified using resonance Raman spectroscopy. Applying this technique to study isolated chloroplasts and whole leaves, we show here that the same change in neoxanthin configuration occurs in vivo, to an extent consistent with the magnitude of energy dissipation. Femtosecond transient absorption spectroscopy, performed on purified LHCII in the dissipative state, shows that energy is transferred from chlorophyll a to a low-lying carotenoid excited state, identified as one of the two luteins (lutein 1) in LHCII. Hence, it is experimentally demonstrated that a change in conformation of LHCII occurs in vivo, which opens a channel for energy dissipation by transfer to a bound carotenoid. We suggest that this is the principal mechanism of photoprotection.

  4. The switching mechanism of the mitochondrial ADP/ATP carrier explored by free-energy landscapes.

    Science.gov (United States)

    Pietropaolo, Adriana; Pierri, Ciro Leonardo; Palmieri, Ferdinando; Klingenberg, Martin

    2016-06-01

    The ADP/ATP carrier (AAC) of mitochondria has been an early example for elucidating the transport mechanism alternating between the external (c-) and internal (m-) states (M. Klingenberg, Biochim. Biophys. Acta 1778 (2008) 1978-2021). An atomic resolution crystal structure of AAC is available only for the c-state featuring a three repeat transmembrane domain structure. Modeling of transport mechanism remained hypothetical for want of an atomic structure of the m-state. Previous molecular dynamics studies simulated the binding of ADP or ATP to the AAC remaining in the c-state. Here, a full description of the AAC switching from the c- to the m-state is reported using well-tempered metadynamics simulations. Free-energy landscapes of the entire translocation from the c- to the m-state, based on the gyration radii of the c- and m-gates and of the center of mass, were generated. The simulations revealed three free-energy basins attributed to the c-, intermediate- and m-states separated by activation barriers. These simulations were performed with the empty and with the ADP- and ATP-loaded AAC as well as with the poorly transported AMP and guanine nucleotides, showing in the free energy landscapes that ADP and ATP lowered the activation free-energy barriers more than the other substrates. Upon binding AMP and guanine nucleotides a deeper free-energy level stabilized the intermediate-state of the AAC2 hampering the transition to the m-state. The structures of the substrate binding sites in the different states are described producing a full picture of the translocation events in the AAC.

  5. Comparison of gold nanoparticle mediated photoporation: vapor nanobubbles outperform direct heating for delivering macromolecules in live cells.

    Science.gov (United States)

    Xiong, Ranhua; Raemdonck, Koen; Peynshaert, Karen; Lentacker, Ine; De Cock, Ine; Demeester, Jo; De Smedt, Stefaan C; Skirtach, Andre G; Braeckmans, Kevin

    2014-06-24

    There is a great interest in delivering macromolecular agents into living cells for therapeutic purposes, such as siRNA for gene silencing. Although substantial effort has gone into designing nonviral nanocarriers for delivering macromolecules into cells, translocation of the therapeutic molecules from the endosomes after endocytosis into the cytoplasm remains a major bottleneck. Laser-induced photoporation, especially in combination with gold nanoparticles, is an alternative physical method that is receiving increasing attention for delivering macromolecules in cells. By allowing gold nanoparticles to bind to the cell membrane, nanosized membrane pores can be created upon pulsed laser illumination. Depending on the laser energy, pores are created through either direct heating of the AuNPs or by vapor nanobubbles (VNBs) that can emerge around the AuNPs. Macromolecules in the surrounding cell medium can then diffuse through the pores directly into the cytoplasm. Here we present a systematic evaluation of both photoporation mechanisms in terms of cytotoxicity, cell loading, and siRNA transfection efficiency. We find that the delivery of macromolecules under conditions of VNBs is much more efficient than direct photothermal disturbance of the plasma membrane without any noticeable cytotoxic effect. Interestingly, by tuning the laser energy, the pore size could be changed, allowing control of the amount and size of molecules that are delivered in the cytoplasm. As only a single nanosecond laser pulse is required, we conclude that VNBs are an interesting photoporation mechanism that may prove very useful for efficient high-throughput macromolecular delivery in live cells.

  6. Mechanisms of energy transfer and conversion in plant Light-Harvesting Complex II

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Tiago Ferreira de

    2009-09-24

    subject of this thesis. From the results obtained during this doctoral work, five main conclusions can be drawn concerning the mechanism of qE: 1. Substitution of Vio by Zea in LHC-II is not sufficient for efficient dissipation of excess excitation energy. 2. Aggregation quenching of LHC-II does not require Vio, Neo nor a specific Chl pair. 3. With one exception, the pigment structure in LHC-II is rigid. 4. The two X-ray structures of LHC-II show the same energy transmitting state of the complex. 5. Crystalline LHC-II resembles the complex in the thylakoid membrane. Models of the aggregation quenching mechanism in vitro and the qE mechanism in vivo are presented as a corollary of this doctoral work. LHC-II aggregation quenching in vitro is attributed to the formation of energy sinks on the periphery of LHC-II through random interaction with other trimers, free pigments or impurities. A similar but unrelated process is proposed to occur in the thylakoid membrane, by which excess excitation energy is dissipated upon specific interaction between LHC-II and a PsbS monomer carrying Zea. At the end of this thesis, an innovative experimental model for the analysis of all key aspects of qE is proposed in order to finally solve the qE enigma, one of the last unresolved problems in photosynthesis research. (orig.)

  7. A computational study of the protein-ligand interactions in CDK2 inhibitors: using quantum mechanics/molecular mechanics interaction energy as a predictor of the biological activity.

    Science.gov (United States)

    Alzate-Morales, Jans H; Contreras, Renato; Soriano, Alejandro; Tuñon, Iñaki; Silla, Estanislao

    2007-01-15

    We report a combined quantum mechanics/molecular mechanics (QM/MM) study to determine the protein-ligand interaction energy between CDK2 (cyclin-dependent kinase 2) and five inhibitors with the N(2)-substituted 6-cyclohexyl-methoxy-purine scaffold. The computational results in this work show that the QM/MM interaction energy is strongly correlated to the biological activity and can be used as a predictor, at least within a family of substrates. A detailed analysis of the protein-ligand structures obtained from molecular dynamics simulations shows specific interactions within the active site that, in some cases, have not been reported before to our knowledge. The computed interaction energy gauges the strength of protein-ligand interactions. Finally, energy decomposition and multiple regression analyses were performed to check the contribution of the electrostatic and van der Waals energies to the total interaction energy and to show the capabilities of the computational model to identify new potent inhibitors.

  8. Mechanical energy estimation during walking: validity and sensitivity in typical gait and in children with cerebral palsy.

    Science.gov (United States)

    Van de Walle, P; Hallemans, A; Schwartz, M; Truijen, S; Gosselink, R; Desloovere, K

    2012-02-01

    Gait efficiency in children with cerebral palsy is usually quantified by metabolic energy expenditure. Mechanical energy estimations, however, can be a valuable supplement as they can be assessed during gait analysis and plotted over the gait cycle, thus revealing information on timing and sources of increases in energy expenditure. Unfortunately, little information on validity and sensitivity exists. Three mechanical estimation approaches: (1) centre of mass (CoM) approach, (2) sum of segmental energies (SSE) approach and (3) integrated joint power approach, were validated against oxygen consumption and each other. Sensitivity was assessed in typical gait and in children with diplegia. CoM approach underestimated total energy expenditure and showed poor sensitivity. SSE approach overestimated energy expenditure and showed acceptable sensitivity. Validity and sensitivity were best in the integrated joint power approach. This method is therefore preferred for mechanical energy estimation in children with diplegia. However, mechanical energy should supplement, not replace metabolic energy, as total energy expended is not captured in any mechanical approach.

  9. Physics-based scoring of protein-ligand interactions: explicit polarizability, quantum mechanics and free energies.

    Science.gov (United States)

    Bryce, Richard A

    2011-04-01

    The ability to accurately predict the interaction of a ligand with its receptor is a key limitation in computer-aided drug design approaches such as virtual screening and de novo design. In this article, we examine current strategies for a physics-based approach to scoring of protein-ligand affinity, as well as outlining recent developments in force fields and quantum chemical techniques. We also consider advances in the development and application of simulation-based free energy methods to study protein-ligand interactions. Fuelled by recent advances in computational algorithms and hardware, there is the opportunity for increased integration of physics-based scoring approaches at earlier stages in computationally guided drug discovery. Specifically, we envisage increased use of implicit solvent models and simulation-based scoring methods as tools for computing the affinities of large virtual ligand libraries. Approaches based on end point simulations and reference potentials allow the application of more advanced potential energy functions to prediction of protein-ligand binding affinities. Comprehensive evaluation of polarizable force fields and quantum mechanical (QM)/molecular mechanical and QM methods in scoring of protein-ligand interactions is required, particularly in their ability to address challenging targets such as metalloproteins and other proteins that make highly polar interactions. Finally, we anticipate increasingly quantitative free energy perturbation and thermodynamic integration methods that are practical for optimization of hits obtained from screened ligand libraries.

  10. Generalization of classical mechanics for nuclear motions on nonadiabatically coupled potential energy surfaces in chemical reactions.

    Science.gov (United States)

    Takatsuka, Kazuo

    2007-10-18

    Classical trajectory study of nuclear motion on the Born-Oppenheimer potential energy surfaces is now one of the standard methods of chemical dynamics. In particular, this approach is inevitable in the studies of large molecular systems. However, as soon as more than a single potential energy surface is involved due to nonadiabatic coupling, such a naive application of classical mechanics loses its theoretical foundation. This is a classic and fundamental issue in the foundation of chemistry. To cope with this problem, we propose a generalization of classical mechanics that provides a path even in cases where multiple potential energy surfaces are involved in a single event and the Born-Oppenheimer approximation breaks down. This generalization is made by diagonalization of the matrix representation of nuclear forces in nonadiabatic dynamics, which is derived from a mixed quantum-classical representation of the electron-nucleus entangled Hamiltonian [Takatsuka, K. J. Chem. Phys. 2006, 124, 064111]. A manifestation of quantum fluctuation on a classical subsystem that directly contacts with a quantum subsystem is discussed. We also show that the Hamiltonian thus represented gives a theoretical foundation to examine the validity of the so-called semiclassical Ehrenfest theory (or mean-field theory) for electron quantum wavepacket dynamics, and indeed, it is pointed out that the electronic Hamiltonian to be used in this theory should be slightly modified.

  11. Relative effects of submersion and increased pressure on respiratory mechanics, work, and energy cost of breathing.

    Science.gov (United States)

    Held, Heather E; Pendergast, David R

    2013-03-01

    Submersion and increased pressure (depth) characterize the diving environment and may independently increase demand on the respiratory system. To quantify changes in respiratory mechanics, this study employed a unique protocol and techniques to measure, in a hyperbaric chamber, inspiratory and expiratory alveolar pressures (interrupter technique), inspiratory and expiratory resistance in the airways (RawI and RawE, esophageal balloon technique), nitric oxide elimination (thought to correlate with Raw), inspiratory and expiratory mechanical power of breathing, and the total energy cost of ventilation. Eight healthy adult men underwent experiments at 1, 2.7, and 4.6 atmospheres absolute (ATA) in dry and fully submersed conditions. Subjects rested, cycled on an ergometer at 100 W, and rested while voluntarily matching their ventilation to their own exercise hyperpnea (isocapnic simulated exercise ventilation). During isocapnic simulated exercise ventilation, increased O2 uptake (above rest values) resulted from increased expired ventilation. RawI decreased with submersion (mean 43% during rest and 20% during exercise) but increased from 1 to 4.6 ATA (19% during rest and 75% during exercise), as did RawE (53% decrease with submersion during rest and 10% during exercise; 9% increase from 1 to 4.6 ATA during rest and 66% during exercise). Nitric oxide elimination did not correlate with Raw. Depth increased inspiratory mechanical power of breathing during rest (40%) and exercise (20%). Expiratory mechanical power of breathing was largely unchanged. These results suggest that the diving environment affects ventilatory mechanics primarily by increasing Raw, secondary to increased gas density. This necessitates increased alveolar pressure and increases the work and energy cost of breathing as the diver descends. These findings can inform physician assessment of diver fitness and the pulmonary risks of hyperbaric O2 therapy.

  12. Mechanical characterization of an electrostrictive polymer for actuation and energy harvesting

    Science.gov (United States)

    Eddiai, A.; Meddad, M.; Touhtouh, S.; Hajjaji, A.; Boughaleb, Y.; Guyomar, D.; Belkhiat, S.; Sahraoui, B.

    2012-06-01

    Electroactive polymers have been widely used as smart material for actuators in recent years. Electromechanical applications are currently focused on energy harvesting and actuation, including the development of wireless portable electronic equipment autonomous and specific actuators such as artificial muscles. The problem to be solved is to make its devices the most efficient, as possible in terms of harvested energy and action. These two criteria are controlled by the permittivity of the electrostrictive polymer used, the Young's modulus, and their dependence on frequency and level of stress. In the present paper, we presented a model describing the mechanical behaviour of electrostrictive polymers with taking into account the mechanical losses. Young's modulus follows a linear function of strain and stress. However, when the elongation becomes higher, the data obtained from this strain linear trend and significant hysteresis loops appear the reflections on the existence of mechanical losses. In this work, to provide the analysis of the experimental observations, we utilized a theoretical model in order to define a constitutive law implying a representative relationship between stress and strain. After detailing this theoretical model, the simulation results are compared with experimental ones. The results show that hysteresis loss increases with the increase of frequency and strain amplitude. The model used here is in good agreement with the experimental results.

  13. Mechanism and bounding of earthquake energy input to building structure on surface ground subjected to engineering bedrock motion

    OpenAIRE

    Kojima, K; Sakaguchi, K; Takewaki, I.

    2015-01-01

    The mechanism of earthquake energy input to building structures is clarified by considering the surface ground amplification and soil–structure interaction. The earthquake input energies to superstructures, soil–foundation systems and total swaying–rocking system are obtained by taking the corresponding appropriate free bodies into account and defining the energy transfer functions. It has been made clear that, when the ground surface motion is white, the input energy to the swaying–rocking m...

  14. [Possible changes in energy-minimizer mechanisms of locomotion due to chronic low back pain - a literature review].

    Science.gov (United States)

    de Carvalho, Alberito Rodrigo; Andrade, Alexandro; Peyré-Tartaruga, Leonardo Alexandre

    2015-01-01

    One goal of the locomotion is to move the body in the space at the most economical way possible. However, little is known about the mechanical and energetic aspects of locomotion that are affected by low back pain. And in case of occurring some damage, little is known about how the mechanical and energetic characteristics of the locomotion are manifested in functional activities, especially with respect to the energy-minimizer mechanisms during locomotion. This study aimed: a) to describe the main energy-minimizer mechanisms of locomotion; b) to check if there are signs of damage on the mechanical and energetic characteristics of the locomotion due to chronic low back pain (CLBP) which may endanger the energy-minimizer mechanisms. This study is characterized as a narrative literature review. The main theory that explains the minimization of energy expenditure during the locomotion is the inverted pendulum mechanism, by which the energy-minimizer mechanism converts kinetic energy into potential energy of the center of mass and vice-versa during the step. This mechanism is strongly influenced by spatio-temporal gait (locomotion) parameters such as step length and preferred walking speed, which, in turn, may be severely altered in patients with chronic low back pain. However, much remains to be understood about the effects of chronic low back pain on the individual's ability to practice an economic locomotion, because functional impairment may compromise the mechanical and energetic characteristics of this type of gait, making it more costly. Thus, there are indications that such changes may compromise the functional energy-minimizer mechanisms. Copyright © 2014 Elsevier Editora Ltda. All rights reserved.

  15. Triplet-triplet energy transfer and protection mechanisms against singlet oxygen in photosynthesis

    Science.gov (United States)

    Kihara, Shigeharu

    In photosynthesis, (bacterio)chlorophylls ((B)Chl) play a crucial role in light harvesting and electron transport. (B)Chls, however, are known to be potentially dangerous due to the formation of the triplet excited state which forms the singlet oxygen (1O2*) when exposed to the sunlight. Singlet oxygen is highly reactive and all modern organisms incorporate special protective mechanisms to minimize the oxidative damage. One of the conventional photoprotective mechanisms used by photosynthetic organisms is by the nearby carotenoids quenching the excess energy and releasing it by heat. In this dissertation, two major aspects of this process are studied. First, based on experimental data and model calculations, the oxygen content in a functioning oxygenic photosynthetic oxygen cell was determined. These organisms perform water splitting and as a result significant amount of oxygen can be formed within the organism itself. It was found, that contrary to some published estimates, the excess oxygen concentration generated within an individual cell is extremely low -- 0.025 ... 0.25 microM, i.e. about 103-104 times lower than the oxygen concentration in air saturated water. Such low concentrations imply that the first oxygenic photosynthetic cells that evolved in oxygen-free atmosphere of the Earth ~2.8 billion years ago might have invented the water splitting machinery (photosystem II) without the need for special oxygen-protective mechanisms, and the latter mechanisms could have evolved in the next 500 million years during slow rise of oxygen in the atmosphere. This result also suggests that proteins within photosynthetic membranes are not exposed to significant O2 levels and thus can be studied in vitro under the usual O2 levels. Second, the fate of triplet excited states in the Fenna Matthew Olson (FMO) pigment-protein complex is studied by means of time-resolved nanosecond spectroscopy and exciton model simulations. For the first time, the properties of several

  16. On the matching equations of energy shaping controllers for mechanical systems

    Science.gov (United States)

    Crasta, N.; Ortega, Romeo; Pillai, Harish K.

    2015-09-01

    Total energy shaping is a controller design methodology that achieves (asymptotic) stabilisation of mechanical systems endowing the closed-loop system with a Lagrangian or Hamiltonian structure with a desired energy function. The success of the method relies on the possibility of solving two partial differential equations (PDEs) which identify the kinetic and potential energy functions that can be assigned to the closed loop. Particularly troublesome is the PDE associated to the kinetic energy (KE) which is quasi-linear and non-homogeneous, and the solution that defines the desired inertia matrix must be positive definite. This task is simplified by the inclusion of gyroscopic forces in the target dynamics, which translates into the presence of a free skew-symmetric matrix in the KE matching equation that reduces the number of PDEs to be solved. Recently, it has been claimed that considering a more general form for the target dynamic forces that relax the skew-symmetry condition further reduces the number of KE PDEs. The purpose of this paper is to prove that this claim is wrong.

  17. Broadband Energy Harvester Using Non-linear Polymer Spring and Electromagnetic/Triboelectric Hybrid Mechanism

    Science.gov (United States)

    Gupta, Rahul Kumar; Shi, Qiongfeng; Dhakar, Lokesh; Wang, Tao; Heng, Chun Huat; Lee, Chengkuo

    2017-01-01

    Over the years, several approaches have been devised to widen the operating bandwidth, but most of them can only be triggered at high accelerations. In this work, we investigate a broadband energy harvester based on combination of non-linear stiffening effect and multimodal energy harvesting to obtain high bandwidth over wide range of accelerations (0.1 g–2.0 g). In order to achieve broadband behavior, a polymer based spring exhibiting multimodal energy harvesting is used. Besides, non-linear stiffening effect is introduced by using mechanical stoppers. At low accelerations (energy-harvesting, the obtained bandwidth increases from 23 Hz to 68 Hz with percentage increment of 295% at 1.8 g. Further, we have demonstrated the triboelectric output measured as acceleration sensing signals in terms of voltage and current sensitivity of 4.7 Vg−1 and 19.7 nAg−1, respectively. PMID:28120924

  18. Mechanical motion conversion from reciprocating translation to one-directional rotation for effective energy harvesting

    Science.gov (United States)

    Ahmed, Kabir; Lee, Soobum

    2016-04-01

    This paper proposes a new efficient motion conversion system which can be used in an energy harvesting system that converts wasted kinematic energy into electrical energy. In the proposed system, a reciprocating translational motion will be converted into one-directional rotational motion that spins a generator. The system will be devised with a two overlapping chambers (chamber 1 and 2) which move relatively through the sliding joint, and a pair of flexible strings (belt, steel wire, or chain) run around the rotor of the generator. Each end of the string fixed to chamber 1 is designed not to interfere with chamber 2 where the generator is mounted. When the two chambers move relatively, either top or bottom string is tensioned to spin the rotor while the other string is being rewound. One-directional clutch with a coil spring is engaged in a rewinding system - as found in a rowing machine, for example - so each string actuates the rotor only when it is in tension. This device can be applied to any mechanism where reciprocating translational motion exists, such as linear suspension system in a vehicle, a bicycle, and an energy generating marine buoy. The experimental study result will be reported as well as its battery-charging capacity will be demonstrated.

  19. A Coupled Thermo-Hydro-Mechanical Model of Jointed Hard Rock for Compressed Air Energy Storage

    Directory of Open Access Journals (Sweden)

    Xiaoying Zhuang

    2014-01-01

    Full Text Available Renewable energy resources such as wind and solar are intermittent, which causes instability when being connected to utility grid of electricity. Compressed air energy storage (CAES provides an economic and technical viable solution to this problem by utilizing subsurface rock cavern to store the electricity generated by renewable energy in the form of compressed air. Though CAES has been used for over three decades, it is only restricted to salt rock or aquifers for air tightness reason. In this paper, the technical feasibility of utilizing hard rock for CAES is investigated by using a coupled thermo-hydro-mechanical (THM modelling of nonisothermal gas flow. Governing equations are derived from the rules of energy balance, mass balance, and static equilibrium. Cyclic volumetric mass source and heat source models are applied to simulate the gas injection and production. Evaluation is carried out for intact rock and rock with discrete crack, respectively. In both cases, the heat and pressure losses using air mass control and supplementary air injection are compared.

  20. The high energy limit of the trajectory representation of quantum mechanics

    CERN Document Server

    Floyd, E R

    2003-01-01

    The trajectory representation in the high energy limit (Bohr correspondence principle) manifests a residual indeterminacy. This indeterminacy is compared to the indeterminacy found in the classical limit (Planck's constant to 0) [Int. J. Mod. Phys. A 15, 1363 (2000)] for particles in the classically allowed region, the classically forbiden region, and near the WKB turning point. The differences between Bohr's and Planck's principles for the trajectory representation are compared with the differences between these correspondence principles for the wave representation. The trajectory representation in the high energy limit is shown to go to neither classical nor statistical mechanics. The residual indeterminacy is contrasted to Heisenberg uncertainty. The relationship between indeterminacy and 't Hooft's information loss and equivalence classes is investigated.

  1. Impedance and self-discharge mechanism studies of nickel metal hydride batteries for energy storage applications

    Science.gov (United States)

    Zhu, Wenhua; Zhu, Ying; Tatarchuk, Bruce

    2013-04-01

    Nickel metal hydride battery packs have been found wide applications in the HEVs (hybrid electric vehicles) through the on-board rapid energy conservation and efficient storage to decrease the fossil fuel consumption rate and reduce CO2 emissions as well as other harmful exhaust gases. In comparison to the conventional Ni-Cd battery, the Ni-MH battery exhibits a relatively higher self-discharge rate. In general, there are quite a few factors that speed up the self-discharge of the electrodes in the sealed nickel metal hydride batteries. This disadvantage eventually reduces the overall efficiency of the energy conversion and storage system. In this work, ac impedance data were collected from the nickel metal hydride batteries. The self-discharge mechanism and battery capacity degradation were analyzed and discussed for further performance improvement.

  2. Interplay between electrical and mechanical domains in a high performance nonlinear energy harvester

    Science.gov (United States)

    Mallick, Dhiman; Amann, Andreas; Roy, Saibal

    2015-12-01

    This paper reports a comprehensive experimental characterization and modeling of a compact nonlinear energy harvester for low frequency applications. By exploiting the interaction between the electrical circuitry and the mechanical motion of the device, we are able to improve the power output over a large frequency range. This improvement is quantified using a new figure of merit based on a suitably defined ‘power integral (P f)’ for nonlinear vibrational energy harvesters. The developed device consists of beams with fixed-guided configuration which produce cubic monostable nonlinearity due to stretching strain. Using a high efficiency magnetic circuit a maximum output power of 488.47 μW across a resistive load of 4000 Ω under 0.5g input acceleration at 77 Hz frequency with 9.55 Hz of bandwidth is obtained. The dynamical characteristics of the device are theoretically reproduced and explained by a modified nonlinear Duffing oscillator model.

  3. Point-source idealization in classical field theories. II. Mechanical energy losses from electromagnetic radiation reaction

    Science.gov (United States)

    Kates, Ronald E.; Rosenblum, Arnold

    1982-05-01

    This paper compares the mechanical energy losses due to electromagnetic radiation reaction on a two-particle, slow-motion system, as calculated from (1) the method of matched asymptotic expansions and (2) the Lorentz-Dirac equation, which assumes point sources. The matching derivation of the preceding paper avoided the assumption of a δ-function source by using Reissner-Nordström matching zones. Despite the differing mathematical assumptions of the two methods, their results are in agreement with each other and with the electromagnetic-field energy losses calculated by the evaluation of flux integrals. Our purpose is eventually to analyze Rosenblum's use of point sources as a possible cause of disagreement between the analogous calculations of gravitational radiation on a slow-motion system of two bodies. We begin with the simpler electromagnetic problem.

  4. Alternating access mechanisms of LeuT-fold transporters: trailblazing towards the promised energy landscapes.

    Science.gov (United States)

    Kazmier, Kelli; Claxton, Derek P; Mchaourab, Hassane S

    2016-12-29

    Secondary active transporters couple the uphill translocation of substrates to electrochemical ion gradients. Transporter conformational motion, generically referred to as alternating access, enables a central ligand binding site to change its orientation relative to the membrane. Here we review themes of alternating access and the transduction of ion gradient energy to power this process in the LeuT-fold class of transporters where crystallographic, computational and spectroscopic approaches have converged to yield detailed models of transport cycles. Specifically, we compare findings for the Na(+)-coupled amino acid transporter LeuT and the Na(+)-coupled hydantoin transporter Mhp1. Although these studies have illuminated multiple aspects of transporter structures and dynamics, a number of questions remain unresolved that so far hinder understanding transport mechanisms in an energy landscape perspective.

  5. Simulative Calculation of Mechanical Property, Binding Energy and Detonation Property of TATB/Fluorine-polymer PBX

    Institute of Scientific and Technical Information of China (English)

    MA, Xiu-Fang; XIAO, Ji-Jun; HUANG, Hui; JU, Xue-Hai; LI, Jin-Shan; XIAO, He-Ming

    2006-01-01

    Molecular dynamics (MD) method was used to simulate 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) coated with fluorine containing polymers. The mechanical properties and binding energies of PBXs were obtained. It was found that when the number of chain monomers of fluorine containing polymers was the same, the elasticity of TATB/F2314 was increased more greatly than others and the binding energy of TATB/F2311 was the largest among four PBXs. Detonation heat and velocity of such four PBXs were calculated according to theoretical and empirical formulas. The results show that the order of detonation heat is TATB>TATB/PVDF>TATB/F2311 >TATB/F2314>TATB/PCTFE while the order of detonation velocity is TATB/PVDF<TATB/F2311 <TATB/F2314<TATB/PCTFE<TATB.

  6. Syntrophic growth with direct interspecies electron transfer as the primary mechanism for energy exchange

    DEFF Research Database (Denmark)

    Shrestha, Pravin Malla; Rotaru, Amelia-Elena; Aklujkar, Muktak

    2013-01-01

    Direct interspecies electron transfer (DIET) through biological electrical connections is an alternative to interspecies H2 transfer as a mechanism for electron exchange in syntrophic cultures. However, it has not previously been determined whether electrons received via DIET yield energy...... dehydrogenase, the pilus-associated c-type cytochrome OmcS and pili consistent with electron transfer via DIET. These results suggest that electrons transferred via DIET can serve as the sole energy source to support anaerobic respiration....... to support cell growth. In order to investigate this, co-cultures of Geobacter metallireducens, which can transfer electrons to wild-type G. sulfurreducens via DIET, were established with a citrate synthase-deficient G. sulfurreducens strain that can receive electrons for respiration through DIET only...

  7. A review of net metering mechanism for electricity renewable energy sources

    Directory of Open Access Journals (Sweden)

    Andreas Poullikkas, George Kourtis, Ioannis Hadjipaschalis

    2013-01-01

    Full Text Available In this work, an overview of the net metering mechanism for renewable energy sources for power generation (RES-E systems is carried out. In particular, the net metering concept is examined with its benefits and misconceptions. Furthermore, a survey of the current operational net metering schemes in different countries in the world, such as, in Europe, USA, Canada, Thailand and Australia, is carried out. The survey indicated that there are different net metering mechanisms depending on the particularities of each country (or state in the case of USA. Especially, in Europe, only five countries are using net metering in a very simple form, such as, any amount of energy produced by the eligible RES-E technology is compensated from the energy consumed by the RES-E producer, which results to either a less overall electricity bill or to an exception in payment energy taxes. In the USA and the USA territories, any customer’s net excess generation is credited to the customer’s next electricity bill for a 12-month billing cycle at various rates or via a combination between rates. The actual type of net excess generation (NEG credit is decided by a number of set criteria, such as the type of RES-E technology, the RES-E capacity limit, the type of customer and the type of utility. Regarding any excess credit at the end of the 12-month billing cycle, this is either granted to the utilities, or carries over indefinitely to the customer’s next electricity bill, or is reconciled annually at any rate, or provides an option to the customer to choose between the last two options.

  8. External loading does not change energy cost and mechanics of rollerski skating.

    Science.gov (United States)

    Millet, G; Perrey, S; Candau, R; Belli, A; Borrani, F; Rouillon, J D

    1998-08-01

    The purpose of this study was to examine the effects of external loading on the energy cost and mechanics of roller ski skating. A group of 13 highly skilled male cross-country skiers roller skied at 19.0 ( SD 0.1) km x h(-1) without additional load and with loads of 6% and 12% body mass (mb). Oxygen uptake (VO2), knee and ankle joint kinematics, roller-ski electromyogram (EMG) of the vastus lateralis and gastrocnemius lateralis muscles, and roller ski velocity were recorded during the last 40 s of each 4-min period of roller skiing. One-way repeated measures ANOVA revealed that the VO2 expressed relative to total mass (mtot), joint kinetics, eccentric-to-concentric ratio of the integrated EMG, velocity changes within a cycle, and cycle rate did not change significantly with load. The subsequent analysis of the effect of load on each resistance opposing motion suggested that the power to sustain changes in translational kinetic energy, potential energy, and overcoming rolling resistance increased proportionately with the load. The lack of a significant change in VO2/mtot with external loading was associated with a lack of marked change in external mechanical power relative to mtot. The existence of an EMG signal during the eccentric phase prior to the thrust (concentric phase), as well as the lack of significant delay between the two phases, showed that a stretch-shortening cycle (SSC) occurs in roller ski skating. Taken together, the present results would suggest that external loading up to 12% mb does not increase storage and release of elastic energy of lower limb muscles during SSC in roller ski skating.

  9. A review of net metering mechanism for electricity renewable energy sources

    Energy Technology Data Exchange (ETDEWEB)

    Poullikkas, Andreas; Kourtis, George; Hadjipaschalis, Ioannis [Electricity Authority of Cyprus, P.O. Box 24506, 1399 Nicosia (Cyprus)

    2013-07-01

    In this work, an overview of the net metering mechanism for renewable energy sources for power generation (RES-E) systems is carried out. In particular, the net metering concept is examined with its benefits and misconceptions. Furthermore, a survey of the current operational net metering schemes in different countries in the world, such as, in Europe, USA, Canada, Thailand and Australia, is carried out. The survey indicated that there are different net metering mechanisms depending on the particularities of each country (or state in the case of USA). Especially, in Europe, only five countries are using net metering in a very simple form, such as, any amount of energy produced by the eligible RES-E technology is compensated from the energy consumed by the RES-E producer, which results to either a less overall electricity bill or to an exception in payment energy taxes. In the USA and the USA territories, any customer’s net excess generation is credited to the customer’s next electricity bill for a 12-month billing cycle at various rates or via a combination between rates. The actual type of net excess generation (NEG) credit is decided by a number of set criteria, such as the type of RES-E technology, the RES-E capacity limit, the type of customer and the type of utility. Regarding any excess credit at the end of the 12-month billing cycle, this is either granted to the utilities, or carries over indefinitely to the customer’s next electricity bill, or is reconciled annually at any rate, or provides an option to the customer to choose between the last two options.

  10. Centrifuge Modeling of the Thermo-Mechanical Response of Energy Foundations

    Science.gov (United States)

    Goode, Joseph Collin, III

    This thesis presents the results from a series of centrifuge tests performed to understand the profiles of thermo-mechanical axial strain, axial displacement, and axial stress in semi-floating and end-bearing energy foundations installed in dry Nevada sand and Bonny silt layers during different combinations of mechanical loading and foundation heating. In addition to the construction details for the centrifuge scale-model reinforced concrete energy foundations, the results from 1 g thermo-mechanical characterization tests performed on the foundations to evaluate their mechanical and thermal material properties are presented in this thesis. In general, the centrifuge-scale tests involve application of an axial load to the head of the foundation followed by circulation of a heat exchange fluid through embedded tubing to bring the foundation to a constant temperature. After this point, mechanical loads were applied to the foundation to characterize their thermo-mechanical response. Specifically, loading tests to failure were performed on the semi-floating foundation installed in different soil layers to characterize the impact of temperature on the load-settlement curve, and elastic loading tests were performed on the end-bearing foundation to characterize the impact of temperature on the mobilized side shear distributions. During application of mechanical loads and changes in foundation temperature, the axial strains are measured using embedded strain gages. The soil and foundation temperatures, foundation head movement, and soil surface deformations are also monitored to characterize the thermo-mechanical response of the system. The tests performed in this study were used to investigate different phenomena relevant to the thermo-mechanical response of energy foundations. First, the role of end-restraint boundary conditions in both sand and silt were investigated by comparing the strain distributions for the end-bearing and semi-floating foundations in each soil type

  11. Mechanically flexible nanoscale silicon integrated circuits powered by photovoltaic energy harvesters

    Science.gov (United States)

    Shahrjerdi, D.; Bedell, S. W.; Khakifirooz, A.; Cheng, K.

    2016-03-01

    In this work, we demonstrate mechanically flexible extremely thin silicon on insulator (ETSOI) ring oscillators with a stage delay of ∼16 ps at a power supply voltage of 0.9 V. Extensive electrical analyses of the flexible ETSOI devices reveal the unchanged properties of the devices during the layer transfer process. Furthermore, we discuss the use of flexible silicon and gallium arsenide photovoltaic energy harvesters for powering flexible ETSOI ring oscillators under different illumination conditions. Our results illustrate innovative pathways for the implementation of optically powered flexible ETSOI technology in future flexible hybrid electronics.

  12. Automatic mechanical fault assessment of small wind energy systems in microgrids using electric signature analysis

    DEFF Research Database (Denmark)

    Skrimpas, Georgios Alexandros; Marhadi, Kun Saptohartyadi; Jensen, Bogi Bech

    2013-01-01

    A microgrid is a cluster of power generation, consumption and storage systems capable of operating either independently or as part of a macrogrid. The mechanical condition of the power production units, such as the small wind turbines, is considered of crucial importance especially in the case...... of islanded operation. In this paper, the fault assessment is achieved efficiently and consistently via electric signature analysis (ESA). In ESA the fault related frequency components are manifested as sidebands of the existing current and voltage time harmonics. The energy content between the fundamental, 5...... element model where dynamic eccentricity and bearing outer race defect are simulated under varying fault severity and electric loading conditions....

  13. Mechanical Control of ATP Synthase Function: Activation Energy Difference between Tight and Loose Binding Sites

    KAUST Repository

    Beke-Somfai, Tamás

    2010-01-26

    Despite exhaustive chemical and crystal structure studies, the mechanistic details of how FoF1-ATP synthase can convert mechanical energy to chemical, producing ATP, are still not fully understood. On the basis of quantum mechanical calculations using a recent highresolution X-ray structure, we conclude that formation of the P-O bond may be achieved through a transition state (TS) with a planar PO3 - ion. Surprisingly, there is a more than 40 kJ/mol difference between barrier heights of the loose and tight binding sites of the enzyme. This indicates that even a relatively small change in active site conformation, induced by the γ-subunit rotation, may effectively block the back reaction in βTP and, thus, promote ATP. © 2009 American Chemical Society.

  14. Mechanism and Experimental Observability of Global Switching Between Reactive and Nonreactive Coordinates at High Total Energies

    Science.gov (United States)

    Teramoto, Hiroshi; Toda, Mikito; Takahashi, Masahiko; Kono, Hirohiko; Komatsuzaki, Tamiki

    2015-08-01

    We present a mechanism of global reaction coordinate switching, namely, a phenomenon in which the reaction coordinate dynamically switches to another coordinate as the total energy of the system increases. The mechanism is based on global changes in the underlying phase space geometry caused by a switching of dominant unstable modes from the original reactive mode to another nonreactive mode in systems with more than 2 degrees of freedom. We demonstrate an experimental observability to detect a reaction coordinate switching in an ionization reaction of a hydrogen atom in crossed electric and magnetic fields. For this reaction, the reaction coordinate is a coordinate along which electrons escape and its switching changes the escaping direction from the direction of the electric field to that of the magnetic field and, thus, the switching can be detected experimentally by measuring the angle-resolved momentum distribution of escaping electrons.

  15. Polarization energy gradients in combined quantum mechanics, effective fragment potential, and polarizable continuum model calculations.

    Science.gov (United States)

    Li, Hui; Gordon, Mark S

    2007-03-28

    A method that combines quantum mechanics (QM), typically a solute, the effective fragment potential (EFP) discrete solvent model, and the polarizable continuum model is described. The EFP induced dipoles and polarizable continuum model (PCM) induced surface charges are determined in a self-consistent fashion. The gradients of these two energies with respect to molecular coordinate changes are derived and implemented. In general, the gradients can be formulated as simple electrostatic forces and torques among the QM nuclei, electrons, EFP static multipoles, induced dipoles, and PCM induced charges. Molecular geometry optimizations can be performed efficiently with these gradients. The formulas derived for EFPPCM can be generally applied to other combined molecular mechanics and continuum methods that employ induced dipoles and charges.

  16. Coexistence of Two Mechanisms for Extracting Energy from a Rotating Black Hole

    Institute of Scientific and Technical Information of China (English)

    马任意; 汪定雄; 雷卫华

    2003-01-01

    Evolution characteristics of a rotating black hole (BH) are discussed in coexistence of the Blandford-Znajek (BZ)process and the magnetic coupling (MC) process in the parameter space consisting of the BH spin and the powerlaw index of the magnetic field on the disc. The condition for the coexistence of the two energy mechanisms are derived by using the mapping relation between the angular coordinate on the BH horizon and the radial coordinate on the disc. It is shown that not only the two mechanisms can coexist, but also the power and the rate of change of BH entropy in the BZ process will dominate over those in the MC process, provided that the BH spin and the power-law index are great enough.

  17. Why not energy conservation?

    Science.gov (United States)

    Carlson, Shawn

    2016-01-01

    Energy conservation is a deep principle that is obeyed by all of the fundamental forces of nature. It puts stringent constraints on all systems, particularly systems that are ‘isolated,’ meaning that no energy can enter or escape. Notwithstanding the success of the principle of stationary action, it is fair to wonder to what extent physics can be formulated from the principle of stationary energy. We show that if one interprets mechanical energy as a state function, then its stationarity leads to a novel formulation of classical mechanics. However, unlike Lagrangian and Hamiltonian mechanics, which deliver their state functions via algebraic proscriptions (i.e., the Lagrangian is always the difference between a system’s kinetic and potential energies), this new formalism identifies its state functions as the solutions to a differential equation. This is an important difference because differential equations can generate more general solutions than algebraic recipes. When applied to Newtonian systems for which the energy function is separable, these state functions are always the mechanical energy. However, while the stationary state function for a charged particle moving in an electromagnetic field proves not to be energy, the function nevertheless correctly encodes the dynamics of the system. Moreover, the stationary state function for a free relativistic particle proves not to be the energy either. Rather, our differential equation yields the relativistic free-particle Lagrangian (plus a non-dynamical constant) in its correct dynamical context. To explain how this new formalism can consistently deliver stationary state functions that give the correct dynamics but that are not always the mechanical energy, we propose that energy conservation is a specific realization of a deeper principle of stationarity that governs both relativistic and non-relativistic mechanics.

  18. Simple mechanism whereby the F1-ATPase motor rotates with near-perfect chemomechanical energy conversion.

    Science.gov (United States)

    Saita, Ei-ichiro; Suzuki, Toshiharu; Kinosita, Kazuhiko; Yoshida, Masasuke

    2015-08-04

    F1-ATPase is a motor enzyme in which a central shaft γ subunit rotates 120° per ATP in the cylinder made of α3β3 subunits. During rotation, the chemical energy of ATP hydrolysis (ΔGATP) is converted almost entirely into mechanical work by an elusive mechanism. We measured the force for rotation (torque) under various ΔGATP conditions as a function of rotation angles of the γ subunit with quasi-static, single-molecule manipulation and estimated mechanical work (torque × traveled angle) from the area of the function. The torque functions show three sawtooth-like repeats of a steep jump and linear descent in one catalytic turnover, indicating a simple physical model in which the motor is driven by three springs aligned along a 120° rotation angle. Although the second spring is unaffected by ΔGATP, activation of the first spring (timing of the torque jump) delays at low [ATP] (or high [ADP]) and activation of the third spring delays at high [Pi]. These shifts decrease the size and area of the sawtooth (magnitude of the work). Thus, F1-ATPase responds to the change of ΔGATP by shifting the torque jump timing and uses ΔGATP for the mechanical work with near-perfect efficiency.

  19. External mechanical work versus oxidative energy consumption ratio during a basketball field test.

    Science.gov (United States)

    Crisafulli, A; Melis, F; Tocco, F; Laconi, P; Lai, C; Concu, A

    2002-12-01

    A field test consisting of 5 continuous runs at the maximum speed possible, playing the ball, starting from the centre line to the basket with a final shot, was studied in order to obtain an index of mechanical work efficiency in basketball players (micro-index=Jmec/Joxy) and evaluate the correlation between micro-index and velocity, acceleration, mechanical power and lactacid anaerobic capacity, respectively. Eight male basketball players were studied; Jmec was the external mechanical work output obtained by means of a video image analysis software which gave the potential and the kinetic translational energies of athletes running and jumping and their velocity, acceleration and mechanical power. By means of a telemetric device (Kosmed K4), for measuring O2 consumption ( VO2), we obtained oxidative work (Joxy). By using this device we also assessed the excess of CO2, which was considered an index of lactacid anaerobic capacity. Non-parametric Spearman statistics revealed a significant correlation between mu index and mean velocity (ppower (ppower and endurance velocity.

  20. The formation mechanism and the binding energy of the body-centred regular tetrahedral structure of He+5

    Institute of Scientific and Technical Information of China (English)

    李萍; 熊勇; 芶清泉; 张建平

    2002-01-01

    We propose the formation mechanism of the body-centred regular tetrahedral structure of the He+5 cluster. The total energy curve for this structure has been calculated by using a modified arrangement channel quantum mechanics method. The result shows that a minimal energy of -13.9106 a.u. occurs at a separation of 1.14a0 between the nucleus at the centre and nuclei at the apexes. Therefore we obtain the binding energy of 0.5202 a.u. for this structure. This means that the He+5 cluster may be stable with a high binding energy in a body-centred regular tetrahedral structure.

  1. Study of energy transfer mechanism from ZnO nanocrystals to Eu(3+) ions.

    Science.gov (United States)

    Mangalam, Vivek; Pita, Kantisara; Couteau, Christophe

    2016-12-01

    In this work, we investigate the efficient energy transfer occurring between ZnO nanocrystals (ZnO-nc) and europium (Eu(3+)) ions embedded in a SiO2 matrix prepared using the sol-gel technique. We show that a strong red emission was observed at 614 nm when the ZnO-nc were excited using a continuous optical excitation at 325 nm. This emission is due to the radiative (5)D0 → (7)F2 de-excitation of the Eu(3+) ions and has been conclusively shown to be due to the energy transfer from the excited ZnO-nc to the Eu(3+) ions. The photoluminescence excitation spectra are also examined in this work to confirm the energy transfer from ZnO-nc to the Eu(3+) ions. Furthermore, we study various de-excitation processes from the excited ZnO-nc and their contribution to the energy transfer to Eu(3+) ions. We also report the optimum fabrication process for maximum red emission at 614 nm from the samples where we show a strong dependence on the annealing temperature and the Eu(3+) concentration in the sample. The maximum red emission is observed with 12 mol% Eu(3+) annealed at 450 °C. This work provides a better understanding of the energy transfer mechanism from ZnO-nc to Eu(3+) ions and is important for applications in photonics, especially for light emitting devices.

  2. Monocytes harboring cytomegalovirus: interactions with endothelial cells, smooth muscle cells, and oxidized low-density lipoprotein. Possible mechanisms for activating virus delivered by monocytes to sites of vascular injury.

    Science.gov (United States)

    Guetta, E; Guetta, V; Shibutani, T; Epstein, S E

    1997-07-01

    Cytomegalovirus (CMV) infection and its periodic reactivation from latency may contribute to atherogenesis and restenosis. It is unknown how CMV is delivered to the vessel wall and is reactivated. We examined the following hypothesis: CMV, present in monocytes recruited to sites of vascular injury, is activated by endothelial cell (EC) or smooth muscle cell (SMC) contact and by oxidized low-density lipoproteins (oxLDLs). The CMV major immediate-early promoter (MIEP) controls immediate-early (IE) gene expression, and thereby viral replication. To determine whether elements of the vessel wall can activate CMV present in monocytes, we transiently transfected the promonocytic cell line HL-60 with a chloramphenicol acetyltransferase reporter gene construct driven by MIEP. MIEP activity increased 1.7 +/- 0.5-fold (P = .02) when the transfected HL-60 cells were cocultured with ECs, 4.5 +/- 1.5-fold when cocultured with SMCs (P = .03), and 2.0 +/- 0.5-fold (P = .01) when exposed to oxLDL. The combination of oxLDL and EC coculture increased MIEP activity over 7-fold. We also found that freshly isolated human monocytes, infected with endothelium-passaged CMV, were capable of transmitting infectious virus to cocultured ECs or SMCs. CMV-related progression of atherosclerosis or restenosis may, at least in part, involve monocyte delivery of the virus to the site of vascular injury, where the vascular milieu, ie, contact with ECs, SMCs, and oxLDL, can contribute to viral reactivation and/or replication by enhancing CMV IE gene expression. The virus may then infect neighboring ECs or SMCs, initiating a cascade of events predisposing to the development of atherogenesis-related processes.

  3. On the diversity of compact objects within supernova remnants - II. Energy-loss mechanisms

    Science.gov (United States)

    Rogers, Adam; Safi-Harb, Samar

    2017-02-01

    Energy losses from isolated neutron stars are commonly attributed to the emission of electromagnetic radiation from a rotating point-like magnetic dipole in vacuum. This emission mechanism predicts a braking index n = 3, which is not observed in highly magnetized neutron stars. Despite this fact, the assumptions of a dipole field and rapid early rotation are often assumed a priori, typically causing a discrepancy between the characteristic age and the associated supernova remnant (SNR) age. We focus on neutron stars with `anomalous' magnetic fields that have established SNR associations and known ages. Anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs) are usually described in terms of the magnetar model that posits a large magnetic field established by dynamo action. The high magnetic field pulsars (HBPs) have extremely large magnetic fields just above quantum electrodynamics scale (but below that of the AXPs and SGRs), and central compact objects (CCOs) may have buried fields that will emerge in the future as nascent magnetars. In the first part of this series, we examined magnetic field growth as a method of uniting the CCOs with HBPs and X-ray dim isolated neutron stars (XDINSs) through evolution. In this work, we constrain the characteristic age of these neutron stars using the related SNR age for a variety of energy-loss mechanisms and allowing for arbitrary initial spin periods. In addition to the SNR age, we also use the observed braking indices and X-ray luminosities to constrain the models.

  4. An adaptive two-stage energy-efficiency mechanism for the doze mode in EPON

    Science.gov (United States)

    Nikoukar, AliAkbar; Hwang, I.-Shyan; Su, Yu-Min; Liem, Andrew Tanny

    2016-07-01

    Sleep and doze power-saving modes are the common ways to reduce power consumption of optical network units (ONUs) in Ethernet passive optical network (EPON). The doze mode turns off the ONU transmitter when there is no traffic in the upstream direction while the sleep mode turns off the ONU transmitter and receiver. As the result, the sleep mode is more efficient compared to the doze mode, but it introduces additional complexity of scheduling and signaling, losses the clock synchronization and requires long clock recovery time; furthermore, it requires the cooperation of the optical line terminal (OLT) in the downstream direction to queue frames. To improve the energy-saving in the doze mode, a new two-stage mechanism is introduced that the doze sleep duration is extended for longer time with acceptable quality-of-services (QoS) metrics when ONU is idle in the current cycle. By this way the ONU enters the doze mode even in the high load traffic; moreover, the green dynamic bandwidth allocation (GBA) is proposed to calculate the doze sleep duration based on the ONU queue state and incoming traffic ratio. Simulation results show that the proposed mechanism significantly improves the energy-saving 74% and 54% when traffic load is from the light load to the high load in different traffic situations, and also promises the QoS performance.

  5. Impact of Residential Mechanical Ventilation on Energy Cost and Humidity Control

    Energy Technology Data Exchange (ETDEWEB)

    Martin, E.

    2014-01-01

    The DOE Building America program has been conducting research leading to cost effective high performance homes since the early 1990's. Optimizing whole house mechanical ventilation as part of the program's systems engineered approach to constructing housing has been an important subject of the program's research. Ventilation in residential buildings is one component of an effective, comprehensive strategy for creation and maintenance of a comfortable and healthy indoor air environment. The study described in this white paper is based on building energy modeling with an important focus on the indoor humidity impacts of ventilation. The modeling tools used were EnergyPlus version 7.1 (E+) and EnergyGauge USA (EGUSA). Twelve U.S. cities and five climate zones were represented. A total of 864 simulations (2*2*3*3*12= 864) were run using two building archetypes, two building leakage rates, two building orientations, three ventilation systems, three ventilation rates, and twelve climates.

  6. Solvation mechanisms of nedocromil sodium from activation energy and reaction enthalpy measurements of dehydration and dealcoholation.

    Science.gov (United States)

    Richards, Alison C; McColm, Ian J; Harness, J Barrie

    2002-04-01

    Two independent athermal methods of analysis have been used to determine the activation energies associated with the dehydration of nedocromil sodium hydrates. For the highest temperature reaction, monohydrate to the anhydrate, the differences in the measured activation energies indicate a three-dimensional nucleation mechanism in the bulk of the crystal with subsequent three-dimensional anhydrate crystal growth. The number of critical nuclei varies inversely with heating rate. Measured enthalpy values for successive removal of water molecules at 31.7 +/- 1.0, 91.3 +/- 0.8, and 193 +/- 0.6 degrees C are the same, within experimental error, at 21.6 +/- 2.6 kJ (mol H(2)O)(-1), as determined from differential thermal analysis traces. This result implies that an earlier concept of "strong" and "weak" water binding is not relevant and temperatures at which H(2)O molecules are removed is related to nucleation effects and not bond energies. The low temperature shoulder on the 91.3 degrees C peak is identified as an effect arising from open pan analysis conditions. The appearance of "transient" peaks in the conditioning stage of nedocromil sodium trihydrate thermal analysis experiments have been investigated and an explanation based on the presence of alcoholates [(NS)(4) small middle dot 5CH(3)OH, (NS)(5) small middle dot 9C(2)H(5)OH, and (NS)(2) small middle dot C(3)H(7)OH] in the preparations is proposed.

  7. Resting energy expenditure and nitrogen balance in critically ill pediatric patients on mechanical ventilation.

    Science.gov (United States)

    Coss-Bu, J A; Jefferson, L S; Walding, D; David, Y; Smith, E O; Klish, W J

    1998-09-01

    Nutritional support is important in critically ill patients, with variable energy and nitrogen requirements (e.g., sepsis, trauma, postsurgical state) in this population. This study investigates how age, severity of illness, and mechanical ventilation are related to resting energy expenditure (REE) and nitrogen balance. Nineteen critically ill children (mean age, 8 +/- 6 [SD] y and range 0.4-17.0 y) receiving total parenteral nutrition (TPN) were enrolled. We used indirect calorimetry to measure REE. Expected energy requirements (EER) were obtained from Talbot tables. Pediatric Risk of Mortality (PRISM) and Therapeutic Intervention Scoring System (TISS) score were calculated. Total urinary nitrogen was measured using the Kjeldahl method. PRISM and TISS scores were 9 +/- 5 and 31 +/- 6 points, respectively. REE was 62 +/- 25 kcal.kg-1.d-1, EER was 42 +/- 11 kcal.kg-1. d-1, and caloric intake was 49 +/- 22 kcal.kg-1.d-1. Nitrogen intake was 279 +/- 125 mg.kg-1.d-1, total urinary nitrogen was 324 +/- 133 mg.kg-1.d-1, and nitrogen balance was -120 +/- 153 mg.kg-1.d-1. The protein requirement in this population was approximately 2.8 g.kg-1.d-1. These critically ill children were hypermetabolic, with REE 48% higher (20 kcal.kg-1.d-1) than expected. Nitrogen balance significantly correlated with caloric and protein intake, urinary nitrogen, and age, but not with severity of illness scores or ventilatory parameters.

  8. Ultrafast Breakdown of dielectrics: Energy absorption mechanisms investigated by double pulse experiments

    Energy Technology Data Exchange (ETDEWEB)

    Guizard, Stéphane, E-mail: stephane.guizard@cea.fr [Laboratoire des Solides Irradiés, CEA-IRAMIS, CNRS, Ecole Polytechnique, 91128 Palaiseau (France); Klimentov, Sergey [General Physics Institute of the Russian Academy of Sciences, Vavilova St 38, 11991 Moscow (Russian Federation); Mouskeftaras, Alexandros [Laboratoire des Solides Irradiés, CEA-IRAMIS, CNRS, Ecole Polytechnique, 91128 Palaiseau (France); Fedorov, Nikita; Geoffroy, Ghita [Laboratoire CELIA, CNRS-CEA-Université de Bordeaux, Cours de La Libération, Talence (France); Vilmart, Gautier [Laboratoire des Solides Irradiés, CEA-IRAMIS, CNRS, Ecole Polytechnique, 91128 Palaiseau (France)

    2015-05-01

    We investigate the mechanisms involved in the modification of dielectric materials by ultrashort laser pulses. We show that the use of a double pulse (fundamental and second harmonic of a Ti–Sa laser) excitation allows getting new insight in the fundamental processes that occur during the interaction. We first measure the optical breakdown (OB) threshold map (intensity of first pulse versus intensity of second pulse) in various materials (Al{sub 2}O{sub 3}, MgO, α-SiO{sub 2}). Using a simple model that includes multiphoton excitation followed by carrier heating in the conduction band, and assuming that OB occurs when a critical amount of energy is deposited in the material, we can satisfactorily reproduce this evolution of optical breakdown thresholds. The results demonstrate the dominant role of carrier heating in the energy transfer from the laser pulse to the solid. This important phenomenon is also highlighted by the kinetic energy distribution of photoelectrons observed in a photoemission experiment performed under similar conditions of double pulse excitation. Finally we show, in the case of α-SiO{sub 2}, that the initial electronic excitation plays a key role in the formation of surface ripples and that their characteristics are determined by the first pulse, even at intensities well below OB threshold.

  9. Cosmology with a Decaying Vacuum Energy Parametrization Derived from Quantum Mechanics

    CERN Document Server

    Szydlowski, Marek; Urbanowski, Krzysztof

    2015-01-01

    Within the quantum mechanical treatment of the decay problem one finds that at late times $t$ the survival probability of an unstable state cannot have the form of an exponentially decreasing function of time $t$ but it has an inverse power-like form. This is a general property of unstable states following from basic principles of quantum theory. The consequence of this property is that in the case of false vacuum states the cosmological constant becomes dependent on time: $\\Lambda - \\Lambda_{\\text{bare}}\\equiv \\Lambda(t) -\\Lambda_{\\text{bare}} \\sim 1/t^{2}$. We construct the cosmological model with decaying vacuum energy density and matter for solving the cosmological constant problem and the coincidence problem. We show the equivalence of the proposed decaying false vacuum cosmology with the $\\Lambda(t)$ cosmologies (the $\\Lambda(t)$CDM models). The cosmological implications of the model of decaying vacuum energy (dark energy) are discussed. We constrain the parameters of the model with decaying vacuum usin...

  10. Equilibrium Statistical Mechanics and Energy Partition for the Shallow Water Model

    Science.gov (United States)

    Renaud, A.; Venaille, A.; Bouchet, F.

    2016-05-01

    The aim of this paper is to use large deviation theory in order to compute the entropy of macrostates for the microcanonical measure of the shallow water system. The main prediction of this full statistical mechanics computation is the energy partition between a large scale vortical flow and small scale fluctuations related to inertia-gravity waves. We introduce for that purpose a semi-Lagrangian discrete model of the continuous shallow water system, and compute the corresponding statistical equilibria. We argue that microcanonical equilibrium states of the discrete model in the continuous limit are equilibrium states of the actual shallow water system. We show that the presence of small scale fluctuations selects a subclass of equilibria among the states that were previously computed by phenomenological approaches that were neglecting such fluctuations. In the limit of weak height fluctuations, the equilibrium state can be interpreted as two subsystems in thermal contact: one subsystem corresponds to the large scale vortical flow, the other subsystem corresponds to small scale height and velocity fluctuations. It is shown that either a non-zero circulation or rotation and bottom topography are required to sustain a non-zero large scale flow at equilibrium. Explicit computation of the equilibria and their energy partition is presented in the quasi-geostrophic limit for the energy-enstrophy ensemble. The possible role of small scale dissipation and shocks is discussed. A geophysical application to the Zapiola anticyclone is presented.

  11. Reevaluating the mechanism of excitation energy regulation in iron-starved cyanobacteria.

    Science.gov (United States)

    Chen, Hui-Yuan S; Liberton, Michelle; Pakrasi, Himadri B; Niedzwiedzki, Dariusz M

    2017-03-01

    This paper presents spectroscopic investigations of IsiA, a chlorophyll a-binding membrane protein produced by cyanobacteria grown in iron-deficient environments. IsiA, if associated with photosystem I, supports photosystem I in light harvesting by efficiently transferring excitation energy. However, if separated from photosystem I, IsiA exhibits considerable excitation quenching observed as a substantial reduction of protein-bound chlorophyll a fluorescence lifetime. Previous spectroscopic studies suggested that carotenoids are involved in excitation energy dissipation and in addition play a second role in this antenna complex by supporting chlorophyll a in light harvesting by absorbing in the spectral range inaccessible for chlorophyll a and transferring excitation to chlorophylls. However, this investigation does not support these proposed roles of carotenoids in this light harvesting protein. This study shows that carotenoids do not transfer excitation energy to chlorophyll a. In addition, our investigations do not support the hypothesis that carotenoids are quenchers of the excited state of chlorophyll a in this protein complex. We propose that quenching of chlorophyll a fluorescence in IsiA is maintained by pigment-protein interaction via electron transfer from an excited chlorophyll a to a cysteine residue, an excitation quenching mechanism that was recently proposed to regulate the light harvesting capabilities of the bacteriochlorophyll a-containing Fenna-Mathews-Olson protein from green sulfur bacteria. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. A Genome-Scale Model of Shewanella piezotolerans Simulates Mechanisms of Metabolic Diversity and Energy Conservation.

    Science.gov (United States)

    Dufault-Thompson, Keith; Jian, Huahua; Cheng, Ruixue; Li, Jiefu; Wang, Fengping; Zhang, Ying

    2017-01-01

    Shewanella piezotolerans strain WP3 belongs to the group 1 branch of the Shewanella genus and is a piezotolerant and psychrotolerant species isolated from the deep sea. In this study, a genome-scale model was constructed for WP3 using a combination of genome annotation, ortholog mapping, and physiological verification. The metabolic reconstruction contained 806 genes, 653 metabolites, and 922 reactions, including central metabolic functions that represented nonhomologous replacements between the group 1 and group 2 Shewanella species. Metabolic simulations with the WP3 model demonstrated consistency with existing knowledge about the physiology of the organism. A comparison of model simulations with experimental measurements verified the predicted growth profiles under increasing concentrations of carbon sources. The WP3 model was applied to study mechanisms of anaerobic respiration through investigating energy conservation, redox balancing, and the generation of proton motive force. Despite being an obligate respiratory organism, WP3 was predicted to use substrate-level phosphorylation as the primary source of energy conservation under anaerobic conditions, a trait previously identified in other Shewanella species. Further investigation of the ATP synthase activity revealed a positive correlation between the availability of reducing equivalents in the cell and the directionality of the ATP synthase reaction flux. Comparison of the WP3 model with an existing model of a group 2 species, Shewanella oneidensis MR-1, revealed that the WP3 model demonstrated greater flexibility in ATP production under the anaerobic conditions. Such flexibility could be advantageous to WP3 for its adaptation to fluctuating availability of organic carbon sources in the deep sea. IMPORTANCE The well-studied nature of the metabolic diversity of Shewanella bacteria makes species from this genus a promising platform for investigating the evolution of carbon metabolism and energy conservation

  13. Dependence of the mechanical fracture energy of the polymeric composite material from the mixture of filler fractions

    National Research Council Canada - National Science Library

    E M Nurullaev; A S Ermilov

    2015-01-01

    ...) with regard to the basic formulation parameters. By means of the developed computer program the authors calculated the mechanical fracture energy of the polymer binder of the 3D cross-linked plasticized elastomer filled with multifractional silica...

  14. Forget about data, deliver results

    Science.gov (United States)

    Walter, Roland

    2015-12-01

    High-energy astrophysics space missions have pioneered and demonstrated the power of legacy data sets for generating new discoveries, especially when analysed in ways original researchers could not have anticipated. The only way to ensure that the data of present observatories can be effectively used in the future is to allow users to perform on-the-fly data analysis to produce straightforwardly scientific results for any sky position, time and energy intervals without requiring mission specific software or detailed instrumental knowledge. Providing a straightforward interface to complex data and data analysis makes the data and the process of generating science results available to the public and higher education and promotes the visibility of the investment in science to the society. This is a fundamental step to transmit the values of science and to evolve towards a knowledge society.

  15. Intranasal formulations: promising strategy to deliver vaccines.

    Science.gov (United States)

    Riese, Peggy; Sakthivel, Priya; Trittel, Stephanie; Guzmán, Carlos A

    2014-10-01

    The emergence of new diseases and the lack of efficient vaccines against numerous non-treatable pathogens require the development of novel vaccination strategies. To date, only a few mucosal vaccines have been approved for humans. This was in part due to i) the use of live attenuated vaccines, which are not suitable for certain groups of individuals, ii) safety concerns derived from implementation in humans of some mucosal vaccines, iii) the poor stability, absorption and immunogenicity of antigens delivered by the mucosal route and iv) the limited number of available technologies to overcome the bottlenecks associated with mucosal antigen delivery. Recent advances make feasible the development of efficacious mucosal vaccines with adequate safety profile. Thus, currently intranasal vaccines represent an attractive and valid alternative to conventional vaccines. The present review is focused on the potentials and limitations of market-approved intranasal vaccines and promising candidates undergoing clinical investigations. Furthermore, emerging strategies to overcome main bottlenecks including efficient breaching of the mucosal barrier and safety concerns by implementation of new adjuvants and delivery systems are discussed. The rational design of intranasal vaccines requires an in-depth understanding of the anatomic, physicochemical and barrier properties of the nasal mucosa, as well as the molecular mechanisms governing the activation of the local innate and adaptive immune system. This would provide the critical knowledge to establish effective approaches to deliver vaccine antigens across the mucosal barrier, supporting the stimulation of a long-lasting protective response at both mucosal and systemic levels. Current developments in the area of adjuvants, nanotechnologies and mucosal immunology, together with the identification of surface receptors that can be exploited for cell targeting and manipulating their physiological properties, will become instrumental

  16. Mechanical, Biological and Electrochemical Investigations of Advanced Micro/Nano Materials for Tissue Engineering and Energy Storage

    Science.gov (United States)

    Pu, Juan

    Various micro/nano materials have been extensively studied for applications in tissue engineering and energy storage. Tissue engineering seeks to repair or replace damaged tissue by integrating approaches from cellular/molecular biology and material chemistry/engineering. A major challenge is the consistent design of three-dimensional (3D) scaffolds that mimic the structure and biological functions of extracellular matrix (ECM), guide cell migration, provide mechanical support, and regulate cell activity. Electrospun micro/nanofibers have been investigated as promising tissue engineering scaffolds because they resemble native ECM and possess tunable surface morphologies. Supercapacitors, one of the energy storage devices, bridge the performance gap between rechargeable batteries and conventional capacitors. Active electrode materials of supercapacitors must possess high specific surface area, high conductivity, and good electrochemical properties. Carbon-based micro/nano-particles, such as graphene, activated carbon (AC), and carbon nanotubes, are commonly used as active electrode materials for storing charge in supercapacitors by the electrical double layer mechanism due to their high specific surface area and excellent conductivity. In this thesis, the mechanical properties of electrospun bilayer microfibrous membranes were investigated for potential applications in tissue engineering. Bilayer microfibrous membranes of poly(l-lactic acid) (PLLA) were fabricated by electrospinning using a parallel-disk mandrel configuration, which resulted in the sequential deposition of a layer with aligned fibers (AFL) across the two parallel disks and a layer with random fibers (RFL), both deposited by a single process step. The membrane structure and fiber alignment were characterized by scanning electron microscopy and two-dimensional fast Fourier transform. Because of the intricacies of the generated electric field, the bilayer membranes exhibited higher porosity than the

  17. A catalytic mechanism for cysteine N-terminal nucleophile hydrolases, as revealed by free energy simulations.

    Directory of Open Access Journals (Sweden)

    Alessio Lodola

    Full Text Available The N-terminal nucleophile (Ntn hydrolases are a superfamily of enzymes specialized in the hydrolytic cleavage of amide bonds. Even though several members of this family are emerging as innovative drug targets for cancer, inflammation, and pain, the processes through which they catalyze amide hydrolysis remains poorly understood. In particular, the catalytic reactions of cysteine Ntn-hydrolases have never been investigated from a mechanistic point of view. In the present study, we used free energy simulations in the quantum mechanics/molecular mechanics framework to determine the reaction mechanism of amide hydrolysis catalyzed by the prototypical cysteine Ntn-hydrolase, conjugated bile acid hydrolase (CBAH. The computational analyses, which were confirmed in water and using different CBAH mutants, revealed the existence of a chair-like transition state, which might be one of the specific features of the catalytic cycle of Ntn-hydrolases. Our results offer new insights on Ntn-mediated hydrolysis and suggest possible strategies for the creation of therapeutically useful inhibitors.

  18. Kinematic analysis of cable-driven parallel mechanisms based on minimum potential energy principle

    Directory of Open Access Journals (Sweden)

    Guan Liwen

    2015-12-01

    Full Text Available The forward kinematic analysis of the cable-driven parallel mechanism has been a challenging and interesting problem since 10 years ago. This work converts the forward kinematic analysis problem of the cable-driven parallel mechanism to an optimization problem, whose objective is to minimize the potential energy of mobile platform. In order to simplify the optimization problem further so that it can be solved with any simple optimization algorithm in short time, some constraints are introduced to design variables. We utilize the sequential quadratic programming algorithm to solve the simplified optimization problem in this article. The efficiency and effectiveness of the proposed approach are validated with some numerical examples. Furthermore, due to the fact that a required pose may be not stable, the availability of its inverse kinematic solution should be supervised. The aforementioned approach provides a valid tool for solving this type of problems by contrasting the distinction between the required pose and the actual pose calculated by it. The feasibility of applying our proposed method to execute the inverse kinematic analysis of cable-driven parallel mechanism is proved with several examples in this article.

  19. Mechanism Analysis and Experimental Validation of Employing Superconducting Magnetic Energy Storage to Enhance Power System Stability

    Directory of Open Access Journals (Sweden)

    Xiaohan Shi

    2015-01-01

    Full Text Available This paper investigates the mechanism analysis and the experimental validation of employing superconducting magnetic energy storage (SMES to enhance power system stability. The models of the SMES device and the single-machine infinite-bus (SMIB system with SMES are deduced. Based on the model of the SMIB system with SMES, the action mechanism of SMES on a generator is analyzed. The analysis takes the impact of SMES location and the system operating point into consideration, as well. Based on the mechanism analysis, the P-controller and Q-controller are designed utilizing the phase compensation method to improve the damping of the SMIB system. The influence of factors, such as SMES location, transmission system reactance, the dynamic characteristics of SMES and the system operating point, on the damping improvement of SMES, is investigated through root locus analysis. The simulation results of the SMIB test system verify the analysis conclusions and controller design method. The laboratory results of the 150-kJ/100-kW high-temperature SMES (HT-SMES device validate that the SMES device can effectively enhance the damping, as well as the transient stability of the power system.

  20. Binding energy and mechanical stability of single- and multi-walled carbon nanotube serpentines

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Junhua, E-mail: junhua.zhao@163.com, E-mail: timon.rabczuk@uni-weimar.de [Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, Jiangnan University, 214122 Wuxi (China); Institute of Structural Mechanics, Bauhaus University, 99423 Weimar (Germany); Lu, Lixin [Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, Jiangnan University, 214122 Wuxi (China); Rabczuk, Timon, E-mail: junhua.zhao@163.com, E-mail: timon.rabczuk@uni-weimar.de [Institute of Structural Mechanics, Bauhaus University, 99423 Weimar (Germany)

    2014-05-28

    Recently, Geblinger et al. [Nat. Nanotechnol. 3, 195 (2008)] and Machado et al. [Phys. Rev. Lett. 110, 105502 (2013)] reported the experimental and molecular dynamics realization of S-like shaped single-walled carbon nanotubes (CNTs), the so-called CNT serpentines. We reported here results from continuum modeling of the binding energy γ between different single- and multi-walled CNT serpentines and substrates as well as the mechanical stability of the CNT serpentine formation. The critical length for the mechanical stability and adhesion of different CNT serpentines are determined in dependence of E{sub i}I{sub i}, d, and γ, where E{sub i}I{sub i} and d are the CNT bending stiffness and distance of the CNT translation period. Our continuum model is validated by comparing its solution to full-atom molecular dynamics calculations. The derived analytical solutions are of great importance for understanding the interaction mechanism between different single- and multi-walled CNT serpentines and substrates.

  1. Evaluation of Energy Efficiency of Conventional and Mechanized Farmimg System on Potato Production in East Azarbyjan Province

    Directory of Open Access Journals (Sweden)

    M. Izadkhah

    2011-01-01

    Full Text Available Abstract The aims of this study were to evaluation and comparison energy consumption of input and output to potato production by systems of conventional and mechanized farmimg. This research was carried out at arable farmland in East Azarbyjan province in 2006-2007 cropping season. For this purpose, the data were collected from 60 potato farms in East Azarbyjan. Inquiries were conducted in a face-to-face and and grabble statistic, information per Jihad Agriculture Organization of East Azarbyjan province and then used of formula and coefficients special are become equivalent values of used factors and input of this type. The results indicated that total energy inputs in conventional farmimg system (CFS were found to be 60783.24 MJha-1 (direct energy 44.43%, in direct energy 55.57%, renewable energy 46.96% and non-renewabl 53.03% and output (production energy was estimated to be 148268.12 MJ ha-1 and total energy inputs in mechanized farmimg system (MFS was obtaind 52635.73 MJ ha-1 (direct energy 54.17%, in direct energy 45.83%, renewable energy 39.01% and non-renewabl energy 60.94% and output (production energy was 232992.76 MJ ha-1 respectively. The net energy, energy productivity, specific energy value and the ratio of energy outputs to energy inputs was estimated to be 87484.88 MJha-1, 0.58 KgMJ-1, 1.74 MJkg-1 and 2.44, respectively in CFS, and in the MFS was found to be 180357.03 MJ ha-1, 1.04 KgMJ-1, 0.96 MJkg-1 and 4.43 respectively. The results show that the highest share in energy consumption of CFS were: irrigation 24.12%, nitrogen fertilizer 22.36%, seed potato19.72% and also MFS had the biggest share within the total energy inputs includes irrigation 23.21%, nitrogen fertilizer 19.32% and farmer machinery 15.27% respectively. Using the most of energy: Irrigation and nitrogen fertilizer both of the sowing methods can be due to climatic, land topography, society and culture condition of the region. Keywords : Energy efficiency, Input

  2. A simplified model for estimating population-scale energy impacts of building envelope air-tightening and mechanical ventilation retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Logue, J. M.; Turner, W. J.N.; Walker, I. S.; Singer, B. C.

    2015-07-01

    Changing the air exchange rate of a home (the sum of the infiltration and mechanical ventilation airflow rates) affects the annual thermal conditioning energy. Large-scale changes to air exchange rates of the housing stock can significantly alter the residential sector’s energy consumption. However, the complexity of existing residential energy models is a barrier to the accurate quantification of the impact of policy changes on a state or national level.

  3. A piezoelectric six-DOF vibration energy harvester based on parallel mechanism: dynamic modeling, simulation, and experiment

    Science.gov (United States)

    Yuan, G.; Wang, D. H.

    2017-03-01

    Multi-directional and multi-degree-of-freedom (multi-DOF) vibration energy harvesting are attracting more and more research interest in recent years. In this paper, the principle of a piezoelectric six-DOF vibration energy harvester based on parallel mechanism is proposed to convert the energy of the six-DOF vibration to single-DOF vibrations of the limbs on the energy harvester and output voltages. The dynamic model of the piezoelectric six-DOF vibration energy harvester is established to estimate the vibrations of the limbs. On this basis, a Stewart-type piezoelectric six-DOF vibration energy harvester is developed and explored. In order to validate the established dynamic model and the analysis results, the simulation model of the Stewart-type piezoelectric six-DOF vibration energy harvester is built and tested with different vibration excitations by SimMechanics, and some preliminary experiments are carried out. The results show that the vibration of the limbs on the piezoelectric six-DOF vibration energy harvester can be estimated by the established dynamic model. The developed Stewart-type piezoelectric six-DOF vibration energy harvester can harvest the energy of multi-directional linear vibration and multi-axis rotating vibration with resonance frequencies of 17 Hz, 25 Hz, and 47 Hz. Moreover, the resonance frequencies of the developed piezoelectric six-DOF vibration energy harvester are not affected by the direction changing of the vibration excitation.

  4. Quantum mechanics/molecular mechanics modeling of photoelectron spectra: the carbon 1s core-electron binding energies of ethanol-water solutions.

    Science.gov (United States)

    Löytynoja, T; Niskanen, J; Jänkälä, K; Vahtras, O; Rinkevicius, Z; Ågren, H

    2014-11-20

    Using ethanol-water solutions as illustration, we demonstrate the capability of the hybrid quantum mechanics/molecular mechanics (QM/MM) paradigm to simulate core photoelectron spectroscopy: the binding energies and the chemical shifts. An integrated approach with QM/MM binding energy calculations coupled to preceding molecular dynamics sampling is adopted to generate binding energies averaged over the solute-solvent configurations available at a particular temperature and pressure and thus allowing for a statistical assessment with confidence levels for the final binding energies. The results are analyzed in terms of the contributions in the molecular mechanics model-electrostatic, polarization, and van der Waals-with atom or bond granulation of the corresponding MM charge and polarizability force-fields. The role of extramolecular charge transfer screening of the core-hole and explicit hydrogen bonding is studied by extending the QM core to cover the first solvation shell. The results are compared to those obtained from pure electrostatic and polarizable continuum models. Particularly, the dependence of the carbon 1s binding energies with respect to the ethanol concentration is studied. Our results indicate that QM/MM can be used as an all-encompassing model to study photoelectron binding energies and chemical shifts in solvent environments.

  5. The effect of polysaccharides on the ability of whey protein gels to either store or dissipate energy upon mechanical deformation

    NARCIS (Netherlands)

    Darizu Munialo, C.; Linden, E. van der; Ako, K.; Nieuwland, M.; As, H. van; Jongh, H.H.J. de

    2016-01-01

    The addition of polysaccharides to proteins during gel formation can alter the mechanical and textural properties of the resultant gels. However, the effect of addition of different polymers on mechanical properties of whey protein (WP) gels including their ability to elastically store energy, often

  6. The effect of polysaccharides on the ability of whey protein gels to either store or dissipate energy upon mechanical deformation

    NARCIS (Netherlands)

    Munialo, C.D.; Linden, van der E.; Ako, K.; Nieuwland, M.; As, van H.; Jongh, de H.H.J.

    2016-01-01

    The addition of polysaccharides to proteins during gel formation can alter the mechanical and textural properties of the resultant gels. However, the effect of addition of different polymers on mechanical properties of whey protein (WP) gels including their ability to elastically store energy, often

  7. A Brownian Energy Depot Model of the Basilar Membrane Oscillation with a Braking Mechanism

    CERN Document Server

    Zhang, Yong; Lee, Kong-Ju-Bock; Park, Youngah

    2008-01-01

    High auditory sensitivity, sharp frequency selectivity, and otoacoustic emissions are signatures of active amplification of the cochlea. The human ear can also detect very large amplitude sound without being damaged as long as the exposed time is not too long. The outer hair cells are believed as the best candidate for the active force generator of the mammalian cochlea. In this paper, we propose a new model for the basilar membrane oscillation which successfully describes both the active and the protective mechanisms by employing an energy depot concept and a critical velocity of the basilar membrane. One of the main results is that thermal noise in the absence of external stimulation can be amplified leading to the spontaneous basilar membrane oscillation. The compressive response of the basilar membrane at the characteristic frequency and the dynamic response to the stimulation are consistent with the experimental results as expected. Our model also shows the nonlinear distortion of the response of the bas...

  8. A Low-Energy Fast Cyber Foraging Mechanism for Mobile Devices

    CERN Document Server

    Kafaie, Somayeh; Sharifi, Mohsen; 10.5121/ijwmn.2011.3516

    2011-01-01

    The ever increasing demands for using resource-constrained mobile devices for running more resource intensive applications nowadays has initiated the development of cyber foraging solutions that offload parts or whole computational intensive tasks to more powerful surrogate stationary computers and run them on behalf of mobile devices as required. The choice of proper mix of mobile devices and surrogates has remained an unresolved challenge though. In this paper, we propose a new decision-making mechanism for cyber foraging systems to select the best locations to run an application, based on context metrics such as the specifications of surrogates, the specifications of mobile devices, application specification, and communication network specification. Experimental results show faster response time and lower energy consumption of benched applications compared to when applications run wholly on mobile devices and when applications are offloaded to surrogates blindly for execution.

  9. Quantum mechanics, high energy physics and accelerators selected papers of John S Bell (with commentary)

    CERN Document Server

    Bell, John Stewart; Gottfried, Kurt; Veltman, Martinus J G

    1994-01-01

    The scientific career of John Stewart Bell was distinguished by its breadth and its quality. He made several very important contributions to scientific fields as diverse as accelerator physics, high energy physics and the foundations of quantum mechanics. This book contains a large part of J S Bell's publications, including those that are recognized as his most important achievements, as well as others that are for no good reason less well known. The selection was made by Mary Bell, Martinus Veltman and Kurt Gottfried, all of whom were involved with John Bell both personally and professionally throughout a large part of his life. An introductory chapter has been written to help place the selected papers in a historical context and to review their significance. This book comprises an impressive collection of outstanding scientific work of one of the greatest scientists of the recent past, and it will remain important and influential for a long time to come.

  10. Electronic excitation energies, three-state intersections, and photodissociation mechanisms of benzaldehyde and acetophenone

    Science.gov (United States)

    Cui, Ganglong; Lu, You; Thiel, Walter

    2012-06-01

    We report a theoretical study on the electronically excited states and the mechanisms of photodissociation of C6H5CHO and C6H5COCH3. For both molecules, we find an S1/T2/T1 three-state intersection region, which allows for an efficient S1 → T1 intersystem crossing via the T2 state that acts as a relay. Consequently, T1 reactions become the major radical photodissociation channels. According to the computed energy profiles, T1 photodissociation mainly yields phenyl and formyl radicals in the case of benzaldehyde, and benzoyl and methyl radicals in the case of acetophenone, with different C-C bonds being cleaved preferentially. The computational results agree well with the available experimental data.

  11. Equilibrium statistical mechanics and energy partition for the shallow water model

    CERN Document Server

    Renaud, Antoine; Bouchet, Freddy

    2015-01-01

    The aim of this paper is to use large deviation theory in order to compute the entropy of macrostates for the microcanonical measure of the shallow water system. The main prediction of this full statistical mechanics computation is the energy partition between a large scale vortical flow and small scale fluctuations related to inertia-gravity waves. We introduce for that purpose a discretized model of the continuous shallow water system, and compute the corresponding statistical equilibria. We argue that microcanonical equilibrium states of the discretized model in the continuous limit are equilibrium states of the actual shallow water system. We show that the presence of small scale fluctuations selects a subclass of equilibria among the states that were previously computed by phenomenological approaches that were neglecting such fluctuations. In the limit of weak height fluctuations, the equilibrium state can be interpreted as two subsystems in thermal contact: one subsystem corresponds to the large scale v...

  12. On the Diversity of Compact Objects within Supernova Remnants II: Energy Loss Mechanisms

    CERN Document Server

    Rogers, Adam

    2016-01-01

    Energy losses from isolated neutron stars are commonly attributed to the emission of electromagnetic radiation from a rotating point-like magnetic dipole in vacuum. This emission mechanism predicts a braking index $n=3$, which is not observed in highly magnetized neutron stars. Despite this fact, the assumptions of a dipole field and rapid early rotation are often assumed a priori, typically causing a discrepancy between the characteristic age and the associated supernova remnant (SNR) age. We focus on neutron stars with `anomalous' magnetic fields that have established SNR associations and known ages. Anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs) are usually described in terms of the magnetar model, which posits a large magnetic field established by dynamo action. The high magnetic field pulsars (HBPs) have extremely large magnetic fields just above QED scale (but below that of the AXPs and SGRs), and central compact objects (CCOs) may have buried fields that will emerge in the future as nas...

  13. Extrema principles of entropy production and energy dissipation in fluid mechanics

    Science.gov (United States)

    Horne, W. Clifton; Karamcheti, Krishnamurty

    1988-01-01

    A survey is presented of several extrema principles of energy dissipation as applied to problems in fluid mechanics. An exact equation is derived for the dissipation function of a homogeneous, isotropic, Newtonian fluid, with terms associated with irreversible compression or expansion, wave radiation, and the square of the vorticity. By using entropy extrema principles, simple flows such as the incompressible channel flow and the cylindrical vortex are identified as minimal dissipative distributions. The principal notions of stability of parallel shear flows appear to be associated with a maximum dissipation condition. These different conditions are consistent with Prigogine's classification of thermodynamic states into categories of equilibrium, linear nonequilibrium, and nonlinear nonequilibrium thermodynamics; vortices and acoustic waves appear as examples of dissipative structures. The measurements of a typical periodic shear flow, the rectangular wall jet, show that direct measurements of the dissipative terms are possible.

  14. Fluid mechanics simulation of fog formation associated with polluted atmosphere produced by energy related fuel combustion

    Science.gov (United States)

    Hung, R. J.; Liaw, G. S.

    1980-01-01

    It is noted that large quantities of atmospheric aerosols with composition SO4(-2), NO3(-1), and NH4(+1) have been detected in highly industrialized areas. Most aerosol products come from energy-related fuel combustion. Fluid mechanics simulation of both microphysical and macrophysical processes is considered in studying the time dependent evolution of the saturation spectra of condensation nuclei associated with polluted and clean atmospheres during the time periods of advection fog formation. The results demonstrate that the condensation nuclei associated with a polluted atmosphere provide more favorable conditions than condensation nuclei associated with a clean atmosphere to produce dense advection fog, and that attaining a certain degree of supersaturation is not necessarily required for the formation of advection fog having condensation nuclei associated with a polluted atmosphere.

  15. Extrema principles of entrophy production and energy dissipation in fluid mechanics

    Science.gov (United States)

    Horne, W. Clifton; Karamcheti, Krishnamurty

    1988-01-01

    A survey is presented of several extrema principles of energy dissipation as applied to problems in fluid mechanics. An exact equation is derived for the dissipation function of a homogeneous, isotropic, Newtonian fluid, with terms associated with irreversible compression or expansion, wave radiation, and the square of the vorticity. By using entropy extrema principles, simple flows such as the incompressible channel flow and the cylindrical vortex are identified as minimal dissipative distributions. The principal notions of stability of parallel shear flows appears to be associated with a maximum dissipation condition. These different conditions are consistent with Prigogine's classification of thermodynamic states into categories of equilibrium, linear nonequilibrium, and nonlinear nonequilibrium thermodynamics; vortices and acoustic waves appear as examples of dissipative structures. The measurements of a typical periodic shear flow, the rectangular wall jet, show that direct measurements of the dissipative terms are possible.

  16. Determination of Activation Energy of Relaxation Events in Composite Solid Propellants by Dynamic Mechanical Analysis

    Directory of Open Access Journals (Sweden)

    B. K Bihari

    2014-03-01

    Full Text Available The shelf life of a composite solid propellant is one of the critical aspects for the usage of solid propellants. To assess the ageing behavior of the composite solid propellant, the activation energy is a key parameter. The activation energy is determined by analysis of visco-elastic response of the composite solid propellant when subjected to sinusoidal excitation. In the present study, dynamic mechanical analyzer was used to characterize six different types of propellants based on hydroxyl terminated polybutadiene, aluminium, ammonium perchlorate cured with toluene diisocyanate having burning rates varying from 5 mm/s to 25 mm/s at 7000 kPa. Each propellant sample was given a multi-frequency strain of 0.01 percent at three discrete frequencies (3.5 Hz, 11 Hz, 35 Hz in the temperature range -80 °C to + 80 °C. It was observed that all the propellants have shown two relaxation events (α- and β- transition in the temperature range -80 °C to +80 °C. The α-transition was observed between -66 °C and -51 °C and β-transition between 7 °C and 44 °C for the propellants studied. The activation energy for both transitions was determined by Arrhenius plot from dynamic properties measured at different frequencies and also by time temperature superposition principle using Williams-Landel-Ferry and Arrhenius temperature dependence equations. The data reveal that the activation energy corresponding to α-transition varies from 90 kJ/mol to 125 kJ/mol for R-value between 0.7 to 0.9 while for β-transition the values are from 75 kJ/mol to 92 kJ/mol. The activation energy corresponding to β-transition may be used to predict the useful life of solid propellant.Defence Science Journal, 2014, 64(2, pp. 173-178. DOI: http://dx.doi.org/10.14429/dsj.64.3818

  17. Energy Saving Melting and Revert Reduction Technology (E-SMARRT): Mechanical Performance of Dies

    Energy Technology Data Exchange (ETDEWEB)

    R. Allen Miller, Principal Investigator; Kabiri-Bamoradian, Contributors: Khalil; Delgado-Garza, Abelardo; Murugesan, Karthik; Ragab, Adham

    2011-09-13

    As a net shape process, die casting is intrinsically efficient and improvements in energy efficiency are strongly dependent on design and process improvements that reduce scrap rates so that more of the total consumed energy goes into acceptable, usable castings. A casting that is distorted and fails to meet specified dimensional requirements is typically remelted but this still results in a decrease in process yield, lost productivity, and increased energy consumption. This work focuses on developing, and expanding the use of, computer modeling methods that can be used to improve the dimensional accuracy of die castings and produce die designs and machine/die setups that reduce rejection rates due to dimensional issues. A major factor contributing to the dimensional inaccuracy of the casting is the elastic deformations of the die cavity caused by the thermo mechanical loads the dies are subjected to during normal operation. Although thermal and die cavity filling simulation are widely used in the industry, structural modeling of the die, particularly for managing part distortion, is not yet widely practiced. This may be due in part to the need to have a thorough understanding of the physical phenomenon involved in die distortion and the mathematical theory employed in the numerical models to efficiently model the die distortion phenomenon. Therefore, two of the goals of this work are to assist in efforts to expand the use of structural modeling and related technologies in the die casting industry by 1) providing a detailed modeling guideline and tutorial for those interested in developing the necessary skills and capability and 2) by developing simple meta-models that capture the results and experience gained from several years of die distortion research and can be used to predict key distortion phenomena of relevance to a die caster with a minimum of background and without the need for simulations. These objectives were met. A detailed modeling tutorial was

  18. Syntrophic growth with direct interspecies electron transfer as the primary mechanism for energy exchange.

    Science.gov (United States)

    Shrestha, Pravin Malla; Rotaru, Amelia-Elena; Aklujkar, Muktak; Liu, Fanghua; Shrestha, Minita; Summers, Zarath M; Malvankar, Nikhil; Flores, Dan Carlo; Lovley, Derek R

    2013-12-01

    Direct interspecies electron transfer (DIET) through biological electrical connections is an alternative to interspecies H2 transfer as a mechanism for electron exchange in syntrophic cultures. However, it has not previously been determined whether electrons received via DIET yield energy to support cell growth. In order to investigate this, co-cultures of Geobacter metallireducens, which can transfer electrons to wild-type G. sulfurreducens via DIET, were established with a citrate synthase-deficient G. sulfurreducens strain that can receive electrons for respiration through DIET only. In a medium with ethanol as the electron donor and fumarate as the electron acceptor, co-cultures with the citrate synthase-deficient G. sulfurreducens strain metabolized ethanol as fast as co-cultures with wild-type, but the acetate that G. metallireducens generated from ethanol oxidation accumulated. The lack of acetate metabolism resulted in less fumarate reduction and lower cell abundance of G. sulfurreducens. RNAseq analysis of transcript abundance was consistent with a lack of acetate metabolism in G. sulfurreducens and revealed gene expression levels for the uptake hydrogenase, formate dehydrogenase, the pilus-associated c-type cytochrome OmcS and pili consistent with electron transfer via DIET. These results suggest that electrons transferred via DIET can serve as the sole energy source to support anaerobic respiration. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

  19. Thermophysical and Mechanical Properties of Hardened Cement Paste with Microencapsulated Phase Change Materials for Energy Storage

    Directory of Open Access Journals (Sweden)

    Hongzhi Cui

    2014-12-01

    Full Text Available In this research, structural-functional integrated cement-based materials were prepared by employing cement paste and a microencapsulated phase change material (MPCM manufactured using urea-formaldehyde resin as the shell and paraffin as the core material. The encapsulation ratio of the MPCM could reach up to 91.21 wt%. Thermal energy storage cement pastes (TESCPs incorporated with different MPCM contents (5%, 10%, 15%, 20% and 25% by weight of cement were developed, and their thermal and mechanical properties were studied. The results showed that the total energy storage capacity of the hardened cement specimens with MPCM increased by up to 3.9-times compared with that of the control cement paste. The thermal conductivity at different temperature levels (35–36 °C, 55–56 °C and 72–74 °C decreased with the increase of MPCM content, and the decrease was the highest when the temperature level was 55–56 °C. Moreover, the compressive strength, flexural strength and density of hardened cement paste decreased with the increase in MPCM content linearly. Among the evaluated properties, the compressive strength of TESCPs had a larger and faster degradation with the increase of MPCM content.

  20. High-Energy Ion Acceleration Mechanisms in a Dense Plasma Focus Z-Pinch

    Science.gov (United States)

    Higginson, D. P.; Link, A.; Schmidt, A.; Welch, D.

    2016-10-01

    The compression of a Z-pinch plasma, specifically in a dense plasma focus (DPF), is known to accelerate high-energy electrons, ions and, if using fusion-reactant ions (e.g. D, T), neutrons. The acceleration of particles is known to coincide with the peak constriction of the pinch, however, the exact physical mechanism responsible for the acceleration remains an area of debate and uncertainty. Recent work has suggested that this acceleration is linked to the growth of an m =0 (sausage) instability that evacuates a region of low-density, highly-magnetized plasma and creates a strong (>MV/cm) electric field. Using the fully kinetic particle-in-cell code LSP in 2D-3V, we simulate the compression of a 2 MA, 35 kV DPF plasma and investigate in detail the formation of the electric field. The electric field is found to be predominantly in the axial direction and driven via charge-separation effects related to the resistivity of the kinetic plasma. The strong electric and magnetic fields are shown to induce non-Maxwellian distributions in both the ions and electrons and lead to the acceleration of high-energy tails. We compare the results in the kinetic simulations to assumptions of magnetohydrodynamics (MHD). Prepared by LLNL under Contract DE-AC52-07NA27344.

  1. Control of appetite and energy intake by SCFA: what are the potential underlying mechanisms?

    Science.gov (United States)

    Chambers, Edward S; Morrison, Douglas J; Frost, Gary

    2015-08-01

    In recent years, there has been a renewed interest in the role of dietary fibre in obesity management. Much of this interest stems from animal and human studies which suggest that an increased intake of fermentable fibre can suppress appetite and improve weight management. A growing number of reports have demonstrated that the principal products of colonic fermentation of dietary fibre, SCFA, contribute to energy homeostasis via effects on multiple cellular metabolic pathways and receptor-mediated mechanisms. In particular, over the past decade it has been identified that a widespread receptor system exists for SCFA. These G-protein-coupled receptors, free fatty acid receptor (FFAR) 2 and FFAR3 are expressed in numerous tissue sites, including the gut epithelium and adipose tissue. Investigations using FFAR2- or FFAR3-deficient animal models suggest that SCFA-mediated stimulation of these receptors enhances the release of the anorectic hormones peptide tyrosine tyrosine and glucagon-like peptide-1 from colonic L cells and leptin from adipocytes. In addition, the SCFA acetate has recently been shown to have a direct role in central appetite regulation. Furthermore, the SCFA propionate is a known precursor for hepatic glucose production, which has been reported to suppress feeding behaviour in ruminant studies through the stimulation of hepatic vagal afferents. The present review therefore proposes that an elevated colonic production of SCFA could stimulate numerous hormonal and neural signals at different organ and tissue sites that would cumulatively suppress short-term appetite and energy intake.

  2. Time scales and mechanisms of relaxation in the energy landscape of polymer glass under deformation: direct atomistic modeling.

    Science.gov (United States)

    Lyulin, Alexey V; Michels, M A J

    2007-08-24

    Molecular-dynamics simulation is used to explore the influence of thermal and mechanical history of typical glassy polymers on their deformation. Polymer stress-strain and energy-strain developments have been followed for different deformation velocities, also in closed extension-recompression loops. The latter simulate for the first time the experimentally observed mechanical rejuvenation and overaging of polymers, and energy partitioning reveals essential differences between mechanical and thermal rejuvenation. All results can be qualitatively interpreted by considering the ratios of the relevant time scales: for cooling down, for deformation, and for segmental relaxation.

  3. Molecular mechanisms of the angiogenic effects of low-energy shock wave therapy: roles of mechanotransduction.

    Science.gov (United States)

    Hatanaka, Kazuaki; Ito, Kenta; Shindo, Tomohiko; Kagaya, Yuta; Ogata, Tsuyoshi; Eguchi, Kumiko; Kurosawa, Ryo; Shimokawa, Hiroaki

    2016-09-01

    We have previously demonstrated that low-energy extracorporeal cardiac shock wave (SW) therapy improves myocardial ischemia through enhanced myocardial angiogenesis in a porcine model of chronic myocardial ischemia and in patients with refractory angina pectoris. However, the detailed molecular mechanisms for the SW-induced angiogenesis remain unclear. In this study, we thus examined the effects of SW irradiation on intracellular signaling pathways in vitro. Cultured human umbilical vein endothelial cells (HUVECs) were treated with 800 shots of low-energy SW (1 Hz at an energy level of 0.03 mJ/mm(2)). The SW therapy significantly upregulated mRNA expression and protein levels of vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS). The SW therapy also enhanced phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2) and Akt. Furthermore, the SW therapy enhanced phosphorylation of caveolin-1 and the expression of HUTS-4 that represents β1-integrin activity. These results suggest that caveolin-1 and β1-integrin are involved in the SW-induced activation of angiogenic signaling pathways. To further examine the signaling pathways involved in the SW-induced angiogenesis, HUVECs were transfected with siRNA of either β1-integrin or caveolin-1. Knockdown of either caveolin-1 or β1-integrin suppressed the SW-induced phosphorylation of Erk1/2 and Akt and upregulation of VEGF and eNOS. Knockdown of either caveolin-1 or β1-integrin also suppressed SW-induced enhancement of HUVEC migration in scratch assay. These results suggest that activation of mechanosensors on cell membranes, such as caveolin-1 and β1-integrin, and subsequent phosphorylation of Erk and Akt may play pivotal roles in the SW-induced angiogenesis.

  4. Statistical mechanics of chromatin: Inferring free energies of nucleosome formation from high-throughput data sets

    Science.gov (United States)

    Morozov, Alexandre

    2009-03-01

    Formation of nucleosome core particles is a first step towards packaging genomic DNA into chromosomes in living cells. Nucleosomes are formed by wrapping 147 base pairs of DNA around a spool of eight histone proteins. It is reasonable to assume that formation of single nucleosomes in vitro is determined by DNA sequence alone: it costs less elastic energy to wrap a flexible DNA polymer around the histone octamer, and more if the polymer is rigid. However, it is unclear to which extent this effect is important in living cells. Cells have evolved chromatin remodeling enzymes that expend ATP to actively reposition nucleosomes. In addition, nucleosome positioning on long DNA sequences is affected by steric exclusion - many nucleosomes have to form simultaneously without overlap. Currently available bioinformatics methods for predicting nucleosome positions are trained on in vivo data sets and are thus unable to distinguish between extrinsic and intrinsic nucleosome positioning signals. In order to see the relative importance of such signals for nucleosome positioning in vivo, we have developed a model based on a large collection of DNA sequences from nucleosomes reconstituted in vitro by salt dialysis. We have used these data to infer the free energy of nucleosome formation at each position along the genome. The method uses an exact result from the statistical mechanics of classical 1D fluids to infer the free energy landscape from nucleosome occupancy. We will discuss the degree to which in vitro nucleosome occupancy profiles are predictive of in vivo nucleosome positions, and will estimate how many nucleosomes are sequence-specific and how many are positioned purely by steric exclusion. Our approach to nucleosome energetics should be applicable across multiple organisms and genomic regions.

  5. Optimization of Operating Parameters for Minimum Mechanical Specific Energy in Drilling

    Energy Technology Data Exchange (ETDEWEB)

    Hamrick, Todd [West Virginia Univ., Morgantown, WV (United States)

    2011-01-01

    Efficiency in drilling is measured by Mechanical Specific Energy (MSE). MSE is the measure of the amount of energy input required to remove a unit volume of rock, expressed in units of energy input divided by volume removed. It can be expressed mathematically in terms of controllable parameters; Weight on Bit, Torque, Rate of Penetration, and RPM. It is well documented that minimizing MSE by optimizing controllable factors results in maximum Rate of Penetration. Current methods for computing MSE make it possible to minimize MSE in the field only through a trial-and-error process. This work makes it possible to compute the optimum drilling parameters that result in minimum MSE. The parameters that have been traditionally used to compute MSE are interdependent. Mathematical relationships between the parameters were established, and the conventional MSE equation was rewritten in terms of a single parameter, Weight on Bit, establishing a form that can be minimized mathematically. Once the optimum Weight on Bit was determined, the interdependent relationship that Weight on Bit has with Torque and Penetration per Revolution was used to determine optimum values for those parameters for a given drilling situation. The improved method was validated through laboratory experimentation and analysis of published data. Two rock types were subjected to four treatments each, and drilled in a controlled laboratory environment. The method was applied in each case, and the optimum parameters for minimum MSE were computed. The method demonstrated an accurate means to determine optimum drilling parameters of Weight on Bit, Torque, and Penetration per Revolution. A unique application of micro-cracking is also presented, which demonstrates that rock failure ahead of the bit is related to axial force more than to rotation speed.

  6. Micro-cable structured textile for simultaneously harvesting solar and mechanical energy

    Science.gov (United States)

    Chen, Jun; Huang, Yi; Zhang, Nannan; Zou, Haiyang; Liu, Ruiyuan; Tao, Changyuan; Fan, Xing; Wang, Zhong Lin

    2016-10-01

    Developing lightweight, flexible, foldable and sustainable power sources with simple transport and storage remains a challenge and an urgent need for the advancement of next-generation wearable electronics. Here, we report a micro-cable power textile for simultaneously harvesting energy from ambient sunshine and mechanical movement. Solar cells fabricated from lightweight polymer fibres into micro cables are then woven via a shuttle-flying process with fibre-based triboelectric nanogenerators to create a smart fabric. A single layer of such fabric is 320 μm thick and can be integrated into various cloths, curtains, tents and so on. This hybrid power textile, fabricated with a size of 4 cm by 5 cm, was demonstrated to charge a 2 mF commercial capacitor up to 2 V in 1 min under ambient sunlight in the presence of mechanical excitation, such as human motion and wind blowing. The textile could continuously power an electronic watch, directly charge a cell phone and drive water splitting reactions.

  7. Low-energy degassing mechanisms for a fluid-based radioxenon detection system

    Energy Technology Data Exchange (ETDEWEB)

    Russ, W.R.; Stuenkel, D.O.; Valentine, J.D. [Univ. of Cincinnati, OH (United States). Dept. of Mechanical, Industrial and Nuclear Engineering; Gross, K.C. [Argonne National Lab., IL (United States). Reactor Analysis Div.

    1998-09-01

    A method to concentrate heavy noble gases from the atmosphere using certain organic fluids is being developed. To use this technique in a system to monitor the atmosphere for important noble gas fission products (Xe-131, Xe-131m, Xe-133, Xe-133m, and Xe-135) generated by nuclear testing, the radionuclides captured in the fluid must either be detected in the fluid or degassed. This study presents experimental results for a number of possible degassing methods, including heating bubbling with a purge gas, ultrasonic agitation, vacuum, and combinations thereof. Methods were evaluated for energy and time requirements and dilution of the degas product. Initial experiments indicate that in addition to overcoming the standard desorption process dictated by partial pressures per Henry`s Law, a capture mechanism must also be overcome to degas. Some type of agitation, thermal or mechanical, can be used to release weakly trapped gas atoms from the fluid, while diffusional mass transfer can be enhanced through entrainment with a purge gas or use of a vacuum. Ultrasonic agitation of a thin film in a strong vacuum has been shown to be the most effective method of those tested. Implementation of an efficient degas system, along with an absorption system and radioxenon detector could result in an ultrasensitive fluid-based radioxenon measurement system that is more portable, less expensive, and simpler than charcoal-based systems which use cryogenic techniques.

  8. Drug transport mechanism of P-glycoprotein monitored by single molecule fluorescence resonance energy transfer

    Science.gov (United States)

    Ernst, S.; Verhalen, B.; Zarrabi, N.; Wilkens, S.; Börsch, M.

    2011-03-01

    In this work we monitor the catalytic mechanism of P-glycoprotein (Pgp) using single-molecule fluorescence resonance energy transfer (FRET). Pgp, a member of the ATP binding cassette family of transport proteins, is found in the plasma membrane of animal cells where it is involved in the ATP hydrolysis driven export of hydrophobic molecules. When expressed in the plasma membrane of cancer cells, the transport activity of Pgp can lead to the failure of chemotherapy by excluding the mostly hydrophobic drugs from the interior of the cell. Despite ongoing effort, the catalytic mechanism by which Pgp couples MgATP binding and hydrolysis to translocation of drug molecules across the lipid bilayer is poorly understood. Using site directed mutagenesis, we have introduced cysteine residues for fluorescence labeling into different regions of the nucleotide binding domains (NBDs) of Pgp. Double-labeled single Pgp molecules showed fluctuating FRET efficiencies during drug stimulated ATP hydrolysis suggesting that the NBDs undergo significant movements during catalysis. Duty cycle-optimized alternating laser excitation (DCO-ALEX) is applied to minimize FRET artifacts and to select the appropriate molecules. The data show that Pgp is a highly dynamic enzyme that appears to fluctuate between at least two major conformations during steady state turnover.

  9. Maximum-power-point tracking with reduced mechanical stress applied to wind-energy-conversion-systems

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, L.G. [Departamento de Electronica y Comunicaciones, Universidad de los Andes, nucleo la Hechicera, 5101 Merida (Venezuela); Figueres, E.; Garcera, G. [Grupo de Sistemas Electronicos Industriales, Universidad Politecnica de Valencia, Camino de vera s/n, 46022 Valencia (Spain); Carranza, O. [Escuela Superior de Computo, Instituto Politecnico Nacional, Av. Juan de Dios Batiz s/n, 07738 DF (Mexico)

    2010-07-15

    This paper presents an improved maximum-power-point tracking algorithm for wind-energy-conversion-systems. The proposed method significantly reduces the turbine mechanical stress with regard to conventional techniques, so that both the maintenance needs and the medium time between failures are expected to be improved. To achieve these objectives, a sensorless speed control loop receives its reference signal from a modified Perturb and Observe algorithm, in which the typical steps on the reference speed have been substituted by a fixed and well-defined slope ramp signal. As a result, it is achieved a soft dynamic response of both the torque and the speed of the wind turbine, so that the whole system suffers from a lower mechanical stress than with conventional P and O techniques. The proposed method has been applied to a wind turbine based on a permanent magnet synchronous generator operating at variable speed, which is connected to the distribution grid by means of a back to back converter. (author)

  10. Light-matter interaction: conversion of the optical energy and momentum to mechanical vibrations and phonons (Conference Presentation)

    Science.gov (United States)

    Mansuripur, Masud

    2016-09-01

    Interactions between light and material media generally involve an exchange of energy and momentum. Whereas packets of electromagnetic radiation (i.e., photons) are known to carry energy as well as momentum, the eigen-modes of mechanical vibration (i.e., phonons) do not carry any momentum of their own. Considering that, in light-matter interactions, not only the total energy but also the total momentum (i.e., electromagnetic plus mechanical momentum) must be conserved, it becomes necessary to examine the momentum exchange mechanism in some detail. In this presentation, we describe the intricate means by which mechanical momentum is taken up and carried away by material media during reflection, refraction, and absorption of light pulses, thereby ensuring the conservation of linear momentum. Particular attention will be paid to periodically-structured media, which are capable of supporting acoustic as well as optical phonons.

  11. Hull, Mechanical & Electrical (HM &E) Roadmap: Revolutionizing Naval Warfare and Achieving Energy Security

    Science.gov (United States)

    2012-01-01

    railgun , will deliver long- range, precision volume fires, increase stand-off range, and decreased time-to target. Innovative technologies will be...damage  Rapid reaction to moving or swarming targets Hypersonic Technologies Fully electric weapons, such as the Electromagnetic Railgun

  12. Piezoelectric Pre-Stressed Bending Mechanism for Impact-Driven Energy Harvester

    Science.gov (United States)

    Abdal, A. M.; Leong, K. S.

    2017-06-01

    This paper experimentally demonstrates and evaluates a piezoelectric power generator bending mechanism based on pre-stressed condition whereby the piezoelectric transducer being bended and remained in the stressed condition before applying a force on the piezoelectric bending structure, which increase the stress on the piezoelectric surface and hence increase the generated electrical charges. An impact force is being exerted onto bending the piezoelectric beam and hence generating electrical power across an external resistive load. The proposed bending mechanism prototype has been manufactured by employing 3D printer technology in order to conduct the evaluation. A free fall test has been conducted as the evaluation method with varying force using a series of different masses and different fall heights. A rectangular piezoelectric harvester beam with the size of 32mm in width, 70mm in length, and 0.55mm in thickness is used to demonstrate the experiment. It can be seen from the experiment that the instantaneous peak to peak AC volt output measured at open-circuit is increasing and saturated at about of 70V when an impact force of about 80N is being applied. It is also found that a maximum power of about 53mW is generated at an impact force of 50N when it is connected to an external resistive load of 0.7KΩ. The reported mechanism is a promising candidate in the application of energy harvesting for powering various wireless sensor nodes (WSN) which is the core of Internet of Things (IoT).

  13. On a Thermodynamic Mechanism of Dissipation of Mechanical Energy in Porous Elastomers as Applied to the Problem of Heating of Automobile Tires

    Science.gov (United States)

    Grinchuk, P. S.; Shnip, A. I.

    2016-11-01

    It has been shown that in the case of cyclic mechanical loads on a porous elastomer there are regimes in which irreversible processes of heat transfer between the gas and the elastomer are responsible for the appearance of a nonzero heat flux averaged over the period and directed from the gas into the condensed phase; this heat flux is compensated for with the dissipation of mechanical energy from the loading source. A possible influence of this mechanism of dissipation on the heating of automobile tires is assessed. Possible methods of recording of this effect are discussed.

  14. A "test of concept" comparison of aerodynamic and mechanical resuspension mechanisms for particles deposited on field rye grass ( Secale cercele).—Part 2. Threshold mechanical energies for resuspension particle fluxes

    Science.gov (United States)

    Gillette, Dale A.; Lawson, Robert E.; Thompson, Roger S.

    Kinetic energy from the oscillatory impacts of the grass stalk against a stationary object was measured with a kinetic energy measuring device. These energy inputs were measured as part of a resuspension experiment of uniform latex microspheres deposited on a single rye grass seed pod in a wind tunnel. The experiment was designed to measure resuspension from aerodynamic (viscous and turbulent) mechanisms compared to that from mechanisms from mechanical resuspension resulting from the oscillatory impact of the grass hitting a stationary object. The experiment was run for deposited spherical latex particles with diameters from 2 to 8.1 μm. Wind tunnel tests were run for wind speeds from 2 to 18.5 m s -1 and a turbulence intensity (root-mean-square fluctuation wind speed/mean wind speed) of 0.1. Our experiments showed the following: Threshold mechanical energy input rates increased from 0.04 to 0.2 μJ s -1 for resuspension of spherical polystyrene latex particles from 2 to 8.1 μm diameter. Kinetic energy flux generated by mechanical impact of the wind-driven oscillating grass was found to be highly sensitive to slightly different placements and grass morphology. The kinetic energy input by impaction of the grass against a stationary cylinder is roughly proportional to the kinetic energy flux of the wind.

  15. Experimental evidence for quantum cutting co-operative energy transfer process in Pr(3+)/Yb(3+) ions co-doped fluorotellurite glass: dispute over energy transfer mechanism.

    Science.gov (United States)

    Balaji, Sathravada; Ghosh, Debarati; Biswas, Kaushik; Gupta, Gaurav; Annapurna, Kalyandurg

    2016-12-07

    Pr(3+)/Yb(3+) doped materials have been widely reported as quantum-cutting materials in recent times. However, the question of the energy transfer mechanism in the Pr(3+)/Yb(3+) pair in light of the quantum-cutting phenomenon still remains unanswered. In view of that, we explored a series of Pr(3+)/Yb(3+) co-doped low phonon fluorotellurite glass systems to estimate the probability of different energy transfer mechanisms. Indeed, a novel and simple way to predict the probability of the proper energy transfer mechanism in the Pr(3+)/Yb(3+) pair is possible by considering the donor Pr(3+) ion emission intensities and the relative ratio dependence in the presence of acceptor Yb(3+) ions. Moreover, the observed results are very much in accordance with other estimated results that support the quantum-cutting phenomena in Pr(3+)/Yb(3+) pairs, such as sub-linear power dependence of Yb(3+) NIR emission upon visible ∼450 nm laser excitation, integrated area of the donor Pr(3+) ion's visible excitation spectrum recorded by monitoring the acceptor Yb(3+) ion's NIR emission, and the experimentally obtained absolute quantum yield values using an integrating sphere setup. Our results give a simple way of estimating the probability of an energy transfer mechanism and the factors to be considered, particularly for the Pr(3+)/Yb(3+) pair.

  16. Expanding Newton Mechanics with Neutrosophy and Quadstage Method ──New Newton Mechanics Taking Law of Conservation of Energy as Unique Source Law

    Directory of Open Access Journals (Sweden)

    Fu Yuhua

    2014-06-01

    Full Text Available Neutrosophy is a new branch of philosophy, and "Quad-stage" (Four stages is the expansion of Hegel’s triad thesis, antithesis, synthesis of development. Applying Neutrosophy and "Quad-stage" method, the purposes of this paper are expanding Newton Mechanics and making it become New Newton Mechanics (NNW taking law of conservation of energy as unique source law. In this paper the examples show that in some cases other laws may be contradicted with the law of conservation of energy. The original Newton's three laws and the law of gravity, in principle can be derived by the law of conservation of energy. Through the example of free falling body, this paper derives the original Newton's second law by using the law of conservation of energy, and proves that there is not the contradiction between the original law of gravity and the law of conservation of energy; and through the example of a small ball rolls along the inclined plane (belonging to the problem cannot be solved by general relativity that a body is forced to move in flat space, derives improved Newton's second law and improved law of gravity by using law of conservation of energy. Whether or not other conservation laws (such as the law of conservation of momentum and the law of conservation of angular momentum can be utilized, should be tested by law of conservation of energy. When the original Newton's second law is not correct, then the laws of conservation of momentum and angular momentum are no longer correct; therefore the general forms of improved law of conservation of momentum and improved law of conservation of angular momentum are presented. In the cases that law of conservation of energy cannot be used effectively, New Newton Mechanics will not exclude that according to other theories or accurate experiments to derive the laws or formulas to solve some specific problems. For example, with the help of the result of general relativity, the improved Newton's formula of universal

  17. Capturing the Energy Absorbing Mechanisms of Composite Structures under Crash Loading

    Science.gov (United States)

    Wade, Bonnie

    As fiber reinforced composite material systems become increasingly utilized in primary aircraft and automotive structures, the need to understand their contribution to the crashworthiness of the structure is of great interest to meet safety certification requirements. The energy absorbing behavior of a composite structure, however, is not easily predicted due to the great complexity of the failure mechanisms that occur within the material. Challenges arise both in the experimental characterization and in the numerical modeling of the material/structure combination. At present, there is no standardized test method to characterize the energy absorbing capability of composite materials to aide crashworthy structural design. In addition, although many commercial finite element analysis codes exist and offer a means to simulate composite failure initiation and propagation, these models are still under development and refinement. As more metallic structures are replaced by composite structures, the need for both experimental guidelines to characterize the energy absorbing capability of a composite structure, as well as guidelines for using numerical tools to simulate composite materials in crash conditions has become a critical matter. This body of research addresses both the experimental characterization of the energy absorption mechanisms occurring in composite materials during crushing, as well as the numerical simulation of composite materials undergoing crushing. In the experimental investigation, the specific energy absorption (SEA) of a composite material system is measured using a variety of test element geometries, such as corrugated plates and tubes. Results from several crush experiments reveal that SEA is not a constant material property for laminated composites, and varies significantly with the geometry of the test specimen used. The variation of SEA measured for a single material system requires that crush test data must be generated for a range of

  18. How Far Can Ki-Energy Reach?—A Hypothetical Mechanism for the Generation and Transmission of Ki-Energy

    Directory of Open Access Journals (Sweden)

    S. Tsuyoshi Ohnishi

    2009-01-01

    Full Text Available ‘Ki-energy’, which can be enhanced through the practice of Nishino Breathing Method, was reported to have beneficial health effects. Although Ki-energy can play an important role in complementary and alternative medicine (CAM, as yet it is unknown how Ki-energy is generated, transmitted through air and received by another individual. We previously proposed that Ki-energy may include near-infrared radiation, and that the wavelength was between 800 and 2700 nm. Since Ki-energy is reflected by a mirror, we believe that the ‘Ki-beam’ has a small divergence angle. It can also be guided in a desired direction. The acrylic mirror reflection experiment suggests that the wavelength may be between 800 and 1600 nm. Using a linear variable interference filter, we found that Ki-energy may have a peak around 1000 nm. We have also observed that ‘sensitive’ practitioners responded to Ki sent from a distance of 100 m. All of these results suggest that (i Ki-energy can be guided as a directional ‘beam’ with a small divergence angle; (ii the beam can be reflected by a mirror and (iii Ki-energy may have a specific wavelength. Since these properties are characteristics of the laser radiation, we propose a quantum physics-based mechanism of ‘Light Amplification by the Stimulated Emission of Radiation’ (i.e. LASER for the generation of Ki-energy. Volunteers responded to Ki even with a blindfold. This suggests that the skin must be detecting Ki-energy. We propose that the detector at the skin level may also have the stimulated emission mechanism, which amplifies the weak incident infrared radiation.

  19. Mechanical energy transfers across lower limb segments during stair ascent and descent in young and healthy older adults.

    Science.gov (United States)

    Novak, Alison C; Li, Qingguo; Yang, Shuozhi; Brouwer, Brenda

    2011-07-01

    Older adults present with altered movement patterns during stair negotiation although the extent to which modifications in pattern and speed influence mechanical efficiency is unknown. This study evaluated mechanical energy transfers attributed to active force production during stair negotiation in young and older adults to provide insight into age-related changes in mechanical efficiency. Secondary analysis on data obtained from 23 young (23.7±3.0 years) and 32 older adults (67.0±8.2 years) during self-paced stair ascent and descent was conducted. Mechanical energy expenditures (MEE) during concentric transfer, eccentric transfer and no-transfer phases were determined for the ankle, knee and hip power profiles in the sagittal plane. Mechanical energy compensations (MEC) were also determined at each joint. During ascent, MEEs were similar for young and older adults although older adults compensated ankle muscles to a lesser extent during concentric muscle action. Controlling for cadence eliminated this difference. During descent, older adults demonstrated lower energy expenditures at the ankle and hip and similar expenditures at the knee compared to young adults. Changes in joint MEE in the older group resulted in reduced energy compensation at the ankle during concentric and eccentric activity and at the knee during eccentric activity. These age-related differences in mechanical energy transfers and related adjustments in MEC were not a function of the slower cadence in older adults and suggest a loss in mechanical efficiency. These results provide a benchmark against which physical impairments in older adults may be explored.

  20. Mechanical properties of composites as functions of the syringe storage temperature and energy dose

    Directory of Open Access Journals (Sweden)

    Fernanda Oliveira CHAVES

    2015-04-01

    Full Text Available Objective: To investigate the mechanical properties of different classifications of composites indicated for posterior application as functions of the storage condition and of the energy dose. Material and Methods: Specimens (8x2x2 mm were obtained according to the factors: I Composites (3M ESPE: Filtek P60, Filtek Z350XT, and Filtek Silorane; II Syringe storage conditions: room temperature, aged, oven, refrigerator, and freezer; and III Energy dose: 24 J/cm2 and 48 J/cm2. After photoactivation, the specimens were stored at 37ºC for 24 h. After storage, a three-point bending test was carried out in a universal testing machine at 0.5 mm/min. Flexural strength (S and flexural modulus (E were calculated. Data were analyzed by three-way ANOVA and Tukey's test (α=0.05. Results: Different storage conditions significantly affected the silorane composite for S; conversely, no effects were noted in terms of E. The accelerated aging protocol significantly increased the S of Filtek P60 and Filtek Silorane, whereas storage in the oven significantly decreased the S for all of the composites tested. Filtek P60 was the only composite not affected by the lower storage temperatures tested for S, whereas for the silorane this parameter was impacted at the same conditions. The factor "dose" was not statistically significant. Conclusions: The syringe storage at different temperature conditions proved to influence mostly the flexural strength, a clinically important characteristic considering the posterior indication of the materials tested. The silorane composite should not be stored at lower temperatures.

  1. Controlled passive actuation: concepts for energy efficient actuation using mechanical storage elements and continuously variable transmissions

    NARCIS (Netherlands)

    Dresscher, Douwe

    2016-01-01

    Walking robots consume more energy for locomotion than their wheeled and tracked counterparts. To achieve energy autonomous operation, a robot needs to run on energy that is harvested from its environment. In this light, it is meaningful to address reduction of energy consumption. The contribution

  2. Thermo-hydro-mechanical modeling and analysis of cement-based energy storages for small-scale dwellings

    Science.gov (United States)

    Hailemariam, Henok; Wuttke, Frank

    2016-04-01

    One of the common technologies for balancing the energy demand and supply in district heating, domestic hot water production, thermal power plants and thermal process industries in general is thermal energy storage. Thermal energy storage, in particular sensible heat storage as compared to latent heat storage and thermo-chemical storage, has recently gained much interest in the renewable energy storage sector due to its comparatively low cost and technical development. Sensible heat storages work on the principle of storing thermal energy by raising or lowering the temperature of liquid (commonly water) or solid media, and do not involve material phase change or conversion of thermal energy by chemical reactions or adsorption processes as in latent heat and thermo-chemical storages, respectively. In this study, the coupled thermo-hydro-mechanical behaviour of a cement-based thermal energy storage system for domestic applications has been modeled in both saturated as well as unsaturated conditions using the Finite Element method along with an extensive experimental analysis program for parameter detection. For this purpose, a prototype model is used with three well-known thermal energy storage materials, and the temperature and heat distribution of the system were investigated under specific thermo-hydro-mechanical conditions. Thermal energy samples with controlled water to solids ratio and stored in water for up to 28 days were used for the experimental program. The determination of parameters included: thermal conductivity, specific heat capacity and linear coefficient of thermal expansion (CTE) using a transient line-source measurement technique as well as a steady-state thermal conductivity and expansion meter; mechanical strength parameters such as uni-axial strength, young's modulus of elasticity, poisson's ratio and shear parameters using uniaxial, oedometer and triaxial tests; and hydraulic properties such as hydraulic permeability or conductivity under

  3. Molecular mechanism of carvedilol in attenuating the reversion to fetal energy metabolism during cardiac hypertrophy development

    Institute of Scientific and Technical Information of China (English)

    胡琴; 李隆贵

    2003-01-01

    Objective: To explore the molecular regulation mechanism of carvedilol in attenuating the reversion back towards fetal energy metabolism during the development of cardiac hypertrophy induced by coarctation of abdominal aorta (CAA) in male Wistar rats. Methods: Hemodynamic and ventricular remodeling parameters, free fatty acid content in the serum were measured in the experimental animals at 16 weeks after the surgical CAA, the rats receiving carvedilol intervention (CAR) after CAA, and those with sham operation (SH). The expressions of muscle carnitine palmitoyltransferaseⅠ (M-CPTⅠ) and medium chain acyl-CoA dehydrogenase (MCAD) mRNA in the cardiac myocytes from every group were studied with RT-PCR. Results: Significant left ventricular hypertrophy were observed in the rats 16 weeks after coarctation operation (P<0.05), together with significant free fatty acids accumulation and downregulation of M-CPTⅠ and MCAD mRNA (P<0.05) in CAA group. Carvedilol at a dose of 30 mg/kg/d for 12 weeks inhibited the left ventricular hypertrophy induced by pressure overload and enhanced the gene expressions of rate-limiting enzyme (M-CPTⅠ) and key enzyme of fatty acid (MCAD) in the CAR group compared with CAA group (P<0.05). Conclusion: Pressure overload-induced hypertrophy in CAA rats causes the reversion back towards fetal enery metabolism, that is, downregulates the expressions of rate-limiting enzyme and key enzyme of fatty acid oxidation. The intervention therapy with carvedilol, a vasodilating alpha- and beta-adrenoreceptor antagonist, attenuates the reversion of the metabolic gene expression to fetal type through upregulating M-CPTⅠ and MCAD mRNA expressions. Thus, carvedilol may exert cardioprotective effects on heart failure by the mechanism of preserving the adult metabolic gene regulation.

  4. Variational and perturbative formulations of quantum mechanical/molecular mechanical free energy with mean-field embedding and its analytical gradients

    Science.gov (United States)

    Yamamoto, Takeshi

    2008-12-01

    Conventional quantum chemical solvation theories are based on the mean-field embedding approximation. That is, the electronic wavefunction is calculated in the presence of the mean field of the environment. In this paper a direct quantum mechanical/molecular mechanical (QM/MM) analog of such a mean-field theory is formulated based on variational and perturbative frameworks. In the variational framework, an appropriate QM/MM free energy functional is defined and is minimized in terms of the trial wavefunction that best approximates the true QM wavefunction in a statistically averaged sense. Analytical free energy gradient is obtained, which takes the form of the gradient of effective QM energy calculated in the averaged MM potential. In the perturbative framework, the above variational procedure is shown to be equivalent to the first-order expansion of the QM energy (in the exact free energy expression) about the self-consistent reference field. This helps understand the relation between the variational procedure and the exact QM/MM free energy as well as existing QM/MM theories. Based on this, several ways are discussed for evaluating non-mean-field effects (i.e., statistical fluctuations of the QM wavefunction) that are neglected in the mean-field calculation. As an illustration, the method is applied to an SN2 Menshutkin reaction in water, NH3+CH3Cl→NH3CH3++Cl-, for which free energy profiles are obtained at the Hartree-Fock, MP2, B3LYP, and BHHLYP levels by integrating the free energy gradient. Non-mean-field effects are evaluated to be reaction in water.

  5. Simultaneously Harvesting Thermal and Mechanical Energies based on Flexible Hybrid Nanogenerator for Self-Powered Cathodic Protection.

    Science.gov (United States)

    Zhang, Hulin; Zhang, Shangjie; Yao, Guang; Huang, Zhenlong; Xie, Yuhang; Su, Yuanjie; Yang, Weiqing; Zheng, Chunhua; Lin, Yuan

    2015-12-30

    Metal corrosion occurs anytime and anywhere in nature and the corrosion prevention has a great significance everywhere in national economic development and daily life. Here, we demonstrate a flexible hybrid nanogenerator (NG) that is capable of simultaneously or individually harvesting ambient thermal and mechanical energies and used for a self-powered cathodic protection (CP) system without using an external power source. Because of its double peculiarities of both pyroelectric and piezoelectric properties, a polarized poly(vinylidene fluoride) (PVDF) film-based NG was constructed to scavenge both thermal and mechanical energies. As a supplementary, a triboelectric NG was constructed below the pyro/piezoelectric NG to grab ambient mechanical energy. The output power of the fabricated hybrid NG can be directly used to protect the metal surface from the chemical corrosion. Our results not only verify the feasibility of self-powered CP-based NGs, but also expand potential self-powered applications.

  6. Mechanical function of two ankle extensors in wild turkeys: shifts from energy production to energy absorption during incline versus decline running.

    Science.gov (United States)

    Gabaldón, Annette M; Nelson, Frank E; Roberts, Thomas J

    2004-06-01

    We investigated the mechanical function of two ankle extensor muscles, the lateral gastrocnemius (LG) and peroneus longus (PL), in wild turkeys Meleagris gallopavo during steady speed running. We hypothesized that mechanical work output of the LG and PL during running parallels the demand for mechanical work on the body. The turkeys ran on level, inclined (+6 degrees, +12 degrees ) and declined (-6 degrees, -12 degrees ) treadmills to change the demand for mechanical work. Simultaneous measurements of muscle length (from sonomicrometry) and muscle force (from tendon strain gauges) were used to calculate mechanical work output. During level running at a speed of 2 m s(-1), the LG and PL were both active in stance but produced peak force at different times, at approximately 21% of stance duration for the LG and 70% for the PL. The LG and PL also had different length patterns in stance during level running. The LG underwent little shortening during force production, resulting in negligible net positive work (2.0+/-0.8 J kg(-1)). By contrast, the PL produced force across a stretch-shorten cycle in stance and did significant net positive work (4.7+/-1.6 J kg(-1)). Work outputs for both the LG and PL were directly proportional to running slope. When we increased the demand for net positive work by running the turkeys on an incline, the LG and PL increased stance net positive work output in direct proportion to slope (P<0.05). Stance net positive work output increased to 7.0+/-1.3 J kg(-1) for the LG and 8.1+/-2.9 J kg(-1) for the PL on the steepest incline. Increases in stance net positive work for the LG and PL were associated with increases in net shortening strain and average shortening velocity, but average force in stance remained constant. The LG and PL muscles were also effective energy absorbers during decline running, when there is demand for net negative work on the body. During decline running at 2 m s(-1) on the steepest slope, the LG absorbed 4.6+/-2.2 J kg

  7. Review of the energy rating of dwellings in the European Union as a mechanism for sustainable energy

    Energy Technology Data Exchange (ETDEWEB)

    Miguez, J.L.; Porteiro, J.; Murillo, S.; Moran, J.C.; Granada, E. [E.T.S. Ingenieros Industriales, Universidad de Vigo, Campus Lagoas-Marcosende, s/n 36200 Vigo (Spain); Lopez-Gonzalez, L.M.; Vicuna, J.E. [Depto de Ingenieria Mecanica, Universidad de La Rioja, Escuela Tecnica Superior de Ingenieria Industrial de Logrono, C/Luis de Ulloa, 20, E-26004 Logrono (La Rioja) (Spain)

    2006-02-01

    Reducing emissions of CO{sub 2} and other GHGs is one of the biggest environmental challenges facing the European Union as it strives for sustainable development. If that challenge is to be met, domestic energy consumption must be controlled: it currently accounts for 40% of the total, making it one of the biggest sources of emissions. EU Directives 93/76 and 2002/91 make it compulsory for energy rating systems to be set up to report on consumption in buildings. This paper looks at the various rating systems now up and running, with varying levels of success, in EU countries. However, Denmark's is the only system that can be considered as providing a full energy rating in the sense of awarding a graded score to buildings rather than a simple pass/fail rating, and proposing ways of improving the score obtained. Indeed, many regulations on energy saving in the residential sector are extremely recent, and it is too soon to assess their results. In some States they may also be modified by reforms currently being studied or processed. (author)

  8. Mechanisms of Earth activity forsed by external celestial bodies:energy budjet and nature of cyclicity

    Science.gov (United States)

    Barkin, Yu. V.; Ferrandiz, J. M.

    2003-04-01

    In given report we discuss tidal and non-tidal mechanisms of forced tectonic (endogenous) activity of the Earth caused by gravitational attraction of the Moon, Sun and the planets. On the base of the classical solution of the problem of elasticity for model of the Earth with concentric mass distribution the evaluations of the tidal energy and power of Earth lunar-solar deformations, including their joint effect, were obtained. Important role of the joint energetic effect of rotational deformation of the Earth with lunar and solar tides was illustrated. Gravitational interaction of the Moon and Sun with non-spherical, non-homogeneous shells of the Earth generates big additional mechanical forces and moments of the interaction of the neighboring shells (rigid core, liquid core, mantle, lithosphere and separate plates). Acting of these forces and moments in the different time scales on the corresponding sells generates cyclic perturbations of the tensional state of the shells, their deformations, small relative translational displacements and small relative rotational oscillations of the shells. In geological period of time it leads to a fundamental tectonic reconstruction of the Earth. These additional forces and moments of the cyclic celestial-mechanical nature produce cyclic deformations of the all layers of the body and organize and control practically all natural processes. The additional force between mantle and core is cyclic and characterized by the wide basis of frequencies typical for orbital motions (of the Sun, Moon and planets), for rotational motion of the Earth, Moon and Sun and for many from observed natural processes. The problem about small relative translatory-rotary motion of the two shells separated by the thin viscous-elastic layer is studied. The differential equations of motion were obtained and have been studied in particular cases (plane motion of system; case of two axisymmetrical interacting shells and oth.) by approximate methods of small

  9. A TOU Pricing Mechanism to Promote Renewable Energy Consumption: The Case of the Western Inner Mongolia Grid in China

    OpenAIRE

    Yong-xiu He; Yue-xia Pang; Jie Guan

    2017-01-01

    The curtailment of wind power and photovoltaic power is becoming increasingly serious from the year 2012 to present in China. And the small installed capacity captive coal-fired power plants have been developed rapidly aiming to cut production costs. Therefore, by the substitution of renewable energy for captive coal-fired power plants, this paper establishes a time-of-use (TOU) pricing mechanism with a linkage between the supply side and the demand side to promote renewable energy consumptio...

  10. Thermodynamics of a tropical cyclone: generation and dissipation of mechanical energy in a self-driven convection system

    OpenAIRE

    OZAWA,Hisashi; SHIMOKAWA, Shinya

    2015-01-01

    The formation process of circulatory motion of a tropical cyclone is investigated from a thermodynamic viewpoint. The generation rate of mechanical energy by a fluid motion under diabatic heating and cooling, and the dissipation rate of this energy due to irreversible processes are formulated from the first and second laws of thermodynamics. This formulation is applied to a tropical cyclone, and the formation process of the circulatory motion is examined from a balance between the generation ...

  11. The influence of stroke mechanics into energy cost of elite swimmers.

    Science.gov (United States)

    Barbosa, Tiago M; Fernandes, R J; Keskinen, K L; Vilas-Boas, J P

    2008-05-01

    The purpose of this study was to analyze the relationships between energy cost (C), swimming velocity (v), stroke frequency (SF) and stroke length (SL) in top-level swimmers. Eighteen elite swimmers (four freestylers, five backstrokers, five breaststrokers and four butterflyers) performed an intermittent set of nx200 m swims (nvalve system with low hydrodynamic resistance was used to measure pulmonary ventilation and collect expiratory gases. Blood samples were taken from the ear lobe before and after each swim to analyze the blood lactate concentration (YSI 1500L, Yellow Springs, OH, USA). At Backstroke, Breaststroke and Butterfly strokes, increases of SF were associated to increases of C, even when controlling the v. The increases in SL only promoted significant decreases in the C in Breaststroke. There was a significant and polynomial relationship between v and SF for all competitive swimming techniques. The polynomial relationship between v and SL was significant only in Freestyle and Butterfly stroke. Partial correlations between v and SF controlling the effect of SL and between v and SL controlling the effect of SF, were positive and significant for all techniques. It is concluded that manipulation of stroke mechanics variables (SF and SL) may be one of the factors through which C in competitive swimming can be altered for a given v.

  12. Ultrasensitive Characterization of Mechanical Oscillations and Plasmon Energy Shift in Gold Nanorods.

    Science.gov (United States)

    Soavi, Giancarlo; Tempra, Iacopo; Pantano, Maria F; Cattoni, Andrea; Collin, Stéphane; Biagioni, Paolo; Pugno, Nicola M; Cerullo, Giulio

    2016-02-23

    Mechanical vibrational resonances in metal nanoparticles are intensively studied because they provide insight into nanoscale elasticity and for their potential application to ultrasensitive mass detection. In this paper, we use broadband femtosecond pump-probe spectroscopy to study the longitudinal acoustic phonons of arrays of gold nanorods with different aspect ratios, fabricated by electron beam lithography with very high size uniformity. We follow in real time the impulsively excited extensional oscillations of the nanorods by measuring the transient shift of the localized surface plasmon band. Broadband and high-sensitivity detection of the time-dependent extinction spectra enables one to develop a model that quantitatively describes the periodic variation of the plasmon extinction coefficient starting from the steady-state spectrum with only one additional free parameter. This model allows us to retrieve the time-dependent elongation of the nanorods with an ultrahigh sensitivity and to measure oscillation amplitudes of just a few picometers and plasmon energy shifts on the order of 10(-2) meV.

  13. Chemical and mechanical instabilities in high energy heavy-ion collisions

    Science.gov (United States)

    Gervino, G.; Lavagno, A.; Pigato, D.

    2015-07-01

    We investigate the possible thermodynamic instability in a warm and dense nuclear medium where a phase transition from nucleonic matter to resonance-dominated Δ-matter can take place. Such a phase transition is characterized by both mechanical instability (fluctuations on the baryon density) and by chemical-diffusive instability (fluctuations on the isospin concentration) in asymmetric nuclear matter. Similarly to the liquid-gas phase transition, the nucleonic and the Δ-matter phase have a different isospin density in the mixed phase. In the liquid-gas phase transition, the process of producing a larger neutron excess in the gas phase is referred to as isospin fractionation. A similar effects can occur in the nucleon-Δ matter phase transition due essentially to a Δ- excess in the Δ-matter phase in asymmetric nuclear matter. In this context, we study the hadronic equation of state by means of an effective quantum relativistic mean field model with the inclusion of the full octet of baryons, the Δ-isobar degrees of freedom, and the lightest pseudoscalar and vector mesons. Finally, we will investigate the presence of thermodynamic instabilities in a hot and dense nuclear medium where phases with different values of antibaryon-baryon ratios and strangeness content may coexist. Such a physical regime could be in principle investigated in the future high-energy compressed nuclear matter experiments where will make it possible to create compressed baryonic matter with a high net baryon density.

  14. Energy

    CERN Document Server

    Foland, Andrew Dean

    2007-01-01

    Energy is the central concept of physics. Unable to be created or destroyed but transformable from one form to another, energy ultimately determines what is and isn''t possible in our universe. This book gives readers an appreciation for the limits of energy and the quantities of energy in the world around them. This fascinating book explores the major forms of energy: kinetic, potential, electrical, chemical, thermal, and nuclear.

  15. Energy Saving Melting and Revert Reduction Technology (E-SMARRT): Mechanical Performance of Dies

    Energy Technology Data Exchange (ETDEWEB)

    R. Allen Miller, Principal Investigator; Kabiri-Bamoradian, Contributors: Khalil; Delgado-Garza, Abelardo; Murugesan, Karthik; Ragab, Adham

    2011-09-13

    As a net shape process, die casting is intrinsically efficient and improvements in energy efficiency are strongly dependent on design and process improvements that reduce scrap rates so that more of the total consumed energy goes into acceptable, usable castings. A casting that is distorted and fails to meet specified dimensional requirements is typically remelted but this still results in a decrease in process yield, lost productivity, and increased energy consumption. This work focuses on developing, and expanding the use of, computer modeling methods that can be used to improve the dimensional accuracy of die castings and produce die designs and machine/die setups that reduce rejection rates due to dimensional issues. A major factor contributing to the dimensional inaccuracy of the casting is the elastic deformations of the die cavity caused by the thermo mechanical loads the dies are subjected to during normal operation. Although thermal and die cavity filling simulation are widely used in the industry, structural modeling of the die, particularly for managing part distortion, is not yet widely practiced. This may be due in part to the need to have a thorough understanding of the physical phenomenon involved in die distortion and the mathematical theory employed in the numerical models to efficiently model the die distortion phenomenon. Therefore, two of the goals of this work are to assist in efforts to expand the use of structural modeling and related technologies in the die casting industry by 1) providing a detailed modeling guideline and tutorial for those interested in developing the necessary skills and capability and 2) by developing simple meta-models that capture the results and experience gained from several years of die distortion research and can be used to predict key distortion phenomena of relevance to a die caster with a minimum of background and without the need for simulations. These objectives were met. A detailed modeling tutorial was

  16. A low-frequency wave motion mechanism enables efficient energy transport in carbon nanotubes at high heat fluxes.

    Science.gov (United States)

    Zhang, Xiaoliang; Hu, Ming; Poulikakos, Dimos

    2012-07-11

    The great majority of investigations of thermal transport in carbon nanotubes (CNTs) in the open literature focus on low heat fluxes, that is, in the regime of validity of the Fourier heat conduction law. In this paper, by performing nonequilibrium molecular dynamics simulations we investigated thermal transport in a single-walled CNT bridging two Si slabs under constant high heat flux. An anomalous wave-like kinetic energy profile was observed, and a previously unexplored, wave-dominated energy transport mechanism is identified for high heat fluxes in CNTs, originated from excited low frequency transverse acoustic waves. The transported energy, in terms of a one-dimensional low frequency mechanical wave, is quantified as a function of the total heat flux applied and is compared to the energy transported by traditional Fourier heat conduction. The results show that the low frequency wave actually overtakes traditional Fourier heat conduction and efficiently transports the energy at high heat flux. Our findings reveal an important new mechanism for high heat flux energy transport in low-dimensional nanostructures, such as one-dimensional (1-D) nanotubes and nanowires, which could be very relevant to high heat flux dissipation such as in micro/nanoelectronics applications.

  17. Delivering HPC Systems to 132 Dock

    Energy Technology Data Exchange (ETDEWEB)

    Kettering, Brett Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-23

    The intention of this document is to provide the subcontractor with information to enable trucks delivering HPC (High Performance Computing) systems to the 03-0132, computer rooms with the information they need to do so successfully.

  18. Time Outdoors May Deliver Better Sleep

    Science.gov (United States)

    ... fullstory_163389.html Time Outdoors May Deliver Better Sleep Camping and exposure to natural light helps prime ... Spending time in the outdoors may improve your sleep, a small study suggests. Researchers found that a ...

  19. Analyzing the Impact of Increasing Mechanical Index and Energy Deposition on Shear Wave Speed Reconstruction in Human Liver.

    Science.gov (United States)

    Deng, Yufeng; Palmeri, Mark L; Rouze, Ned C; Rosenzweig, Stephen J; Abdelmalek, Manal F; Nightingale, Kathryn R

    2015-07-01

    Shear wave elasticity imaging (SWEI) has found success in liver fibrosis staging. This work evaluates hepatic SWEI measurement success as a function of push pulse energy using two mechanical index (MI) values (1.6 and 2.2) over a range of pulse durations. Shear wave speed (SWS) was measured in the livers of 26 study subjects with known or potential chronic liver diseases. Each measurement consisted of eight SWEI sequences, each with different push energy configurations. The rate of successful SWS estimation was linearly proportional to the push energy. SWEI measurements with higher push energy were successful in patients for whom standard push energy levels failed. The findings also suggest that liver capsule depth could be used prospectively to identify patients who would benefit from elevated output. We conclude that there is clinical benefit to using elevated acoustic output for hepatic SWS measurement in patients with deeper livers.

  20. Influence of interface energies on solute partitioning mechanisms in doped aluminas

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, Shen J., E-mail: sdillon@illinois.edu [University of Illinois, Materials Science and Engineering, 1304 West Green Street, Champaign, IL 61801 (United States); Harmer, Martin P. [Lehigh University, Center for Advanced Materials and Nanotechnology, 5 East Packer Avenue, Bethlehem, PA 18015 (United States); Rohrer, Gregory S. [Carnegie Mellon University, Department of Materials Science and Engineering, 5000 Forbes Avenue, Pittsburgh, PA 15213 (United States)

    2010-09-15

    The experiments described in this paper have been designed to understand how particular dopants in alumina (Ca, Mg, Si, and Y) affect microstructural development through the energetics of their associated precipitates. Specifically, the role of the interphase boundary energy and precipitation activation energy are considered to be in competition with grain boundary complexion (disorder) transitions for partitioning excess solute. The results reveal a relationship between the relative precipitation activation energy and the temperature at which grain boundary complexion transitions occur. The large differences in activation energy primarily derive from the interphase boundary energy. Precipitates that form lower interphase boundary energies tend to suppress complexion transitions, while systems that contain precipitates with high interphase boundary energies are more susceptible. Based on the findings, a new criterion for additive selection to control complexion transitions and abnormal grain growth is proposed that is based on interfacial energies between the host and precipitate.

  1. The energy policy and sustainability of the subsidy mechanism for retail petroleum products consumed in Trinidad and Tobago

    Energy Technology Data Exchange (ETDEWEB)

    Baksh, Timmy

    2010-09-15

    In 1974 the Petroleum Production Levy and Subsidy Act gave effect to legislation which detailed a mechanism to implement a subsidy on all fuel consumed within, and in the territorial waters of, Trinidad and Tobago. This paper will analyse the underlying principles of this energy policy, follow how the mechanism has evolved over the years and propose new iterations to the existing model in order to reduce the Governments liability. The sustainability of the subsidy will be examined and as well as an in-depth analysis on the possible impact on inflation if this mechanism is removed.

  2. Micellar control of the photooxidation pathways of 10-methyl phenothiazine: electron versus energy transfer mechanisms.

    Science.gov (United States)

    Manju, Thankamoniamma; Manoj, Narayanapillai; López Gejo, Juan; Braun, André M; Oliveros, Esther

    2014-02-01

    10-Methyl phenothiazine (MPS) was chosen as a model compound to investigate the effects of compartmentalisation and of charged interfaces on the primary mechanisms involved in the phototoxic reactions related to phenothiazine drugs. Two most important pathways resulting from the interaction of the triplet excited state of MPS ((3)MPS*) with molecular oxygen ((3)O2) have to be considered: (i) energy transfer producing singlet oxygen ((1)O2) and (ii) electron transfer generating the superoxide anion (O2˙(-)) and the radical cation (MPS˙(+)). The quantum yields of (1)O2 production by MPS solubilized in the dispersed pseudo-phase of aqueous micellar systems were found to be similar to those determined in solvents of various polarities, regardless of the anionic or cationic nature of the surfactant (SDS or CTAC). However, micellar compartmentalisation and surfactant charge affect considerably both the sensitized and the self-sensitized photooxidation of MPS. The formation of 10-methyl phenothiazine sulfoxide (MPSO), produced by the reaction of MPS with (1)O2, proceeds at a higher rate in SDS micelles than in neat polar solvents. This result may be explained by the protonation of the zwitterionic intermediate Z (MPS(+)OO(-)) at the micellar interface to yield the corresponding cation C (MPS(+)OOH) that is stabilized in the negatively charged micelles and reacts much faster with MPS than Z to yield MPSO. The electron transfer reaction from (3)MPS* to O2 yielding MPS˙(+) and O2˙(-) is also enhanced in SDS micelles, as back electron transfer (BET) is prevented by ejection of O2˙(-) to the aqueous bulk phase and stabilization of MPS˙(+) in the anionic micelles. The size of the SDS micelles modulates the relative contribution of each pathway (formation of MPSO or MPS˙(+)) to the overall conversion of MPS to its oxidation products. Photooxidation of MPS in cationic micelles is a very slow process, as the formation of neither C nor MPS˙(+) is favoured in positively

  3. Fabrication mechanism of FeSe superconductors with high-energy ball milling aided sintering process

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shengnan, E-mail: snzhang@c-nin.com [Northwest Institute for Non-Ferrous Metal Research, 710016, Xi' an (China); Liu, Jixing [Northwest Institute for Non-Ferrous Metal Research, 710016, Xi' an (China); School of Materials and Metallurgical, Northeast University, Shenyang, 110016 (China); Feng, Jianqing; Wang, Yao; Ma, Xiaobo; Li, Chengshan; Zhang, Pingxiang [Northwest Institute for Non-Ferrous Metal Research, 710016, Xi' an (China)

    2015-08-01

    FeSe Superconducting bulks with high content of superconducting PbO-type β-FeSe phase were prepared with high-energy ball milling (HEBM) aided sintering process. During this process, precursor powders with certain Fe/Se ratio were ball milled first then sintered. The influences of HEBM process as well as initial Fe/Se ratio on the phase evolution process were systematically discussed. With HEBM process and proper initial Fe/Se ratio, the formation of non-superconducting hexagonal δ-FeSe phase were effectively avoided. FeSe bulk with the critical temperature of 9.0 K was obtained through a simple one-step sintering process with lower sintering temperature. Meanwhile, the phase evolution mechanism of the HEBM precursor powders during sintering was deduced based on both the thermodynamic analysis and step-by-step sintering results. The key function of the HEBM process was to provide a high uniformity of chemical composition distribution, thus to successfully avoide the formation of intermediate product during sintering, including FeSe{sub 2} and Fe{sub 7}Se{sub 8}. Therefore, the fundamental principal for the synthesis of FeSe superconductors were concluded as: HEBM aided sintering process, with the sintering temperature of >635 °C and a slow cooling process. - Highlights: • A novel synthesis technique was developed for FeSe based superconductors. • FeSe bulks with high Tc and high β-FeSe phase content has been obtained. • Phase evolution process for the HEBM aided sintering process was proposed.

  4. Modelling Energy Loss Mechanisms and a Determination of the Electron Energy Scale for the CDF Run II W Mass Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Riddick, Thomas [Univ. College London, Bloomsbury (United Kingdom)

    2012-06-15

    The calibration of the calorimeter energy scale is vital to measuring the mass of the W boson at CDF Run II. For the second measurement of the W boson mass at CDF Run II, two independent simulations were developed. This thesis presents a detailed description of the modification and validation of Bremsstrahlung and pair production modelling in one of these simulations, UCL Fast Simulation, comparing to both geant4 and real data where appropriate. The total systematic uncertainty on the measurement of the W boson mass in the W → eve channel from residual inaccuracies in Bremsstrahlung modelling is estimated as 6.2 ±3.2 MeV/c2 and the total systematic uncertainty from residual inaccuracies in pair production modelling is estimated as 2.8± 2.7 MeV=c2. Two independent methods are used to calibrate the calorimeter energy scale in UCL Fast Simulation; the results of these two methods are compared to produce a measurement of the Z boson mass as a cross-check on the accuracy of the simulation.

  5. Theoretical comparison, equivalent transformation, and conjunction operations of electromagnetic induction generator and triboelectric nanogenerator for harvesting mechanical energy.

    Science.gov (United States)

    Zhang, Chi; Tang, Wei; Han, Changbao; Fan, Fengru; Wang, Zhong Lin

    2014-06-11

    Triboelectric nanogenerator (TENG) is a newly invented technology that is effective using conventional organic materials with functionalized surfaces for converting mechanical energy into electricity, which is light weight, cost-effective and easy scalable. Here, we present the first systematic analysis and comparison of EMIG and TENG from their working mechanisms, governing equations and output characteristics, aiming at establishing complementary applications of the two technologies for harvesting various mechanical energies. The equivalent transformation and conjunction operations of the two power sources for the external circuit are also explored, which provide appropriate evidences that the TENG can be considered as a current source with a large internal resistance, while the EMIG is equivalent to a voltage source with a small internal resistance. The theoretical comparison and experimental validations presented in this paper establish the basis of using the TENG as a new energy technology that could be parallel or possibly equivalently important as the EMIG for general power application at large-scale. It opens a field of organic nanogenerator for chemists and materials scientists who can be first time using conventional organic materials for converting mechanical energy into electricity at a high efficiency. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Hybrid Energy Cell with Hierarchical Nano/Micro-Architectured Polymer Film to Harvest Mechanical, Solar, and Wind Energies Individually/Simultaneously.

    Science.gov (United States)

    Dudem, Bhaskar; Ko, Yeong Hwan; Leem, Jung Woo; Lim, Joo Ho; Yu, Jae Su

    2016-11-09

    We report the creation of hybrid energy cells based on hierarchical nano/micro-architectured polydimethylsiloxane (HNMA-PDMS) films with multifunctionality to simultaneously harvest mechanical, solar, and wind energies. These films consist of nano/micro dual-scale architectures (i.e., nanonipples on inverted micropyramidal arrays) on the PDMS surface. The HNMA-PDMS is replicable by facile and cost-effective soft imprint lithography using a nanoporous anodic alumina oxide film formed on the micropyramidal-structured silicon substrate. The HNMA-PDMS film plays multifunctional roles as a triboelectric layer in nanogenerators and an antireflection layer for dye-sensitized solar cells (DSSCs), as well as a self-cleaning surface. This film is employed in triboelectric nanogenerator (TENG) devices, fabricated by laminating it on indium-tin oxide-coated polyethylene terephthalate (ITO/PET) as a bottom electrode. The large effective contact area that emerged from the densely packed hierarchical nano/micro-architectures of the PDMS film leads to the enhancement of TENG device performance. Moreover, the HNMA-PDMS/ITO/PET, with a high transmittance of >90%, also results in highly transparent TENG devices. By placing the HNMA-PDMS/ITO/PET, where the ITO/PET is coated with zinc oxide nanowires, as the top glass substrate of DSSCs, the device is able to add the functionality of TENG devices, thus creating a hybrid energy cell. The hybrid energy cell can successfully convert mechanical, solar, and wind energies into electricity, simultaneously or independently. To specify the device performance, the effects of external pushing frequency and load resistance on the output of TENG devices are also analyzed, including the photovoltaic performance of the hybrid energy cells.

  7. Study of Thermo-Mechanical Effects Induced in Solids by High Energy Particle Beams: Analytical and Numerical Methods

    CERN Document Server

    Dallocchio, Alessandro; Kurtyka, T; Bertarelli, A

    2008-01-01

    Requirements of modern nuclear physics entail big efforts in the field of particle accelerator technology in order to build powerful machines providing particle beams at higher and higher energies; in this context, the Large Hadron Collider represents the future for particle physics. The LHC stores 360 MJ for each circulating beam; this large amount of energy is potentially destructive for accelerator equipments having direct interaction with particles; the need to handle high thermal loads bestows strategic importance to the study of thermo-mechanical problems in accelerator devices. The aim of this work is the study of thermo-mechanical effects induced in solids by high energy particle beams. Development of facilities devoted to the experimental test of accelerator equipments in real working conditions presents several technical difficulties and high cost; the importance of developing reliable methods and accurate models that could be efficiently applied during the design phase of the most critical particle...

  8. New hybrid method for reactive systems from integrating molecular orbital or molecular mechanics methods with analytical potential energy surfaces.

    Science.gov (United States)

    Espinosa-Garciá, Joaquín; Rangel, Cipriano; Navarrete, Marta; Corchado, José C

    2004-09-15

    A computational approach to calculating potential energy surfaces for reactive systems is presented and tested. This hybrid approach is based on integrated methods where calculations for a small model system are performed by using analytical potential energy surfaces, and for the real system by using molecular orbital or molecular mechanics methods. The method is tested on a hydrogen abstraction reaction by using the variational transition-state theory with multidimensional tunneling corrections. The agreement between the calculated and experimental information depends on the quality of the method chosen for the real system. When the real system is treated by accurate quantum mechanics methods, the rate constants are in excellent agreement with the experimental measurements over a wide temperature range. When the real system is treated by molecular mechanics methods, the results are still good, which is very encouraging since molecular mechanics itself is not at all capable of describing this reactive system. Since no experimental information or additional fits are required to apply this method, it can be used to improve the accuracy of molecular orbital methods or to extend the molecular mechanics method to treat any reactive system with the single constraint of the availability of an analytical potential energy surface that describes the model system.

  9. An Energy-Efficient Mobile Sink-Based Unequal Clustering Mechanism for WSNs.

    Science.gov (United States)

    Gharaei, Niayesh; Abu Bakar, Kamalrulnizam; Mohd Hashim, Siti Zaiton; Hosseingholi Pourasl, Ali; Siraj, Mohammad; Darwish, Tasneem

    2017-08-11

    Network lifetime and energy efficiency are crucial performance metrics used to evaluate wireless sensor networks (WSNs). Decreasing and balancing the energy consumption of nodes can be employed to increase network lifetime. In cluster-based WSNs, one objective of applying clustering is to decrease the energy consumption of the network. In fact, the clustering technique will be considered effective if the energy consumed by sensor nodes decreases after applying clustering, however, this aim will not be achieved if the cluster size is not properly chosen. Therefore, in this paper, the energy consumption of nodes, before clustering, is considered to determine the optimal cluster size. A two-stage Genetic Algorithm (GA) is employed to determine the optimal interval of cluster size and derive the exact value from the interval. Furthermore, the energy hole is an inherent problem which leads to a remarkable decrease in the network's lifespan. This problem stems from the asynchronous energy depletion of nodes located in different layers of the network. For this reason, we propose Circular Motion of Mobile-Sink with Varied Velocity Algorithm (CM2SV2) to balance the energy consumption ratio of cluster heads (CH). According to the results, these strategies could largely increase the network's lifetime by decreasing the energy consumption of sensors and balancing the energy consumption among CHs.

  10. Energy

    CERN Document Server

    Robertson, William C

    2002-01-01

    Confounded by kinetic energy? Suspect that teaching about simple machines isn t really so simple? Exasperated by electricity? If you fear the study of energy is beyond you, this entertaining book will do more than introduce you to the topic. It will help you actually understand it. At the book s heart are easy-to-grasp explanations of energy basics work, kinetic energy, potential energy, and the transformation of energy and energy as it relates to simple machines, heat energy, temperature, and heat transfer. Irreverent author Bill Robertson suggests activities that bring the basic concepts of energy to life with common household objects. Each chapter ends with a summary and an applications section that uses practical examples such as roller coasters and home heating systems to explain energy transformations and convection cells. The final chapter brings together key concepts in an easy-to-grasp explanation of how electricity is generated. Energy is the second book in the Stop Faking It! series published by NS...

  11. The Effect of Neuromuscular Blockade on Oxygen Consumption and Energy Expenditure in Mechanically Ventilated Acute Respiratory Insufficiency Patients

    Directory of Open Access Journals (Sweden)

    Esra Yüksel

    2012-04-01

    Full Text Available Objective: The aim of this study is to investigate the effect of neuromuscular blockade on oxygen consumption and energy expenditure in sedated patients with acute respiratory failure who were followed under mechanical ventilation support. Material and Method: 21 acute respiratory failure patients under mechanical ventilation support were included in the study. All patients were sedated with propofol infusion to have a sedation level of 3 on the Ramsay scale. After adequate sedation and hemodynamic stability was achieved, baseline values of oxygen consumption, carbondioxide production and energy consumption of the patients were measured by indirect calorimetry device and recorded. Neuromuscular transmission was monitorized by TOF-Guard, and then 0,1 mg/kg bolus dose vecuronium was administered to the patients. When TOF 0, 25, 50, 90 values were obtained, oxygen, carbondioxide and energy consumption were measured by indirect calorimetry device and recorded. Results: No statistically significant difference were found between pre- and post-curarisation hemodynamic parameters, ventilation parameters, arterial blood gas values (p>0.05. A statistically significant decrease was observed between the oxygen consumption, carbondioxide production and energy consumption measured before curarisation and when TOF value was 0 (p0.05. Conclusion: It was concluded that the effect of neuromuscular blockage on reducing energy and oxygen consumption should be taken into consideration while calculating the daily energy need in intensive care in patients curarized at TOF 0 level. (Journal of the Turkish Society Intensive Care 2012; 10: 8-12

  12. The role of lock-in mechanisms in transition processes: The case of energy for road transport

    DEFF Research Database (Denmark)

    Klitkou, Antje; Bolwig, Simon; Hansen, Teis

    2015-01-01

    This paper revisits the theoretical concepts of lock-in mechanisms to analyse transition processes in energy production and road transportation in the Nordic countries, focussing on three technology platforms: advanced biofuels, e-mobility and hydrogen and fuel cell electrical vehicles. The paper...... and the differentiation of power. We show that very different path dependencies have been reinforced by the lock-in mechanisms. Hence, the characteristics of existing regimes set the preconditions for the development of new transition pathways. The incumbent socio-technical regime is not just fossil-based, but may also...... include mature niches specialised in the exploitation of renewable sources. This implies a need to distinguish between lock-in mechanisms favouring the old fossil-based regime, well-established (mature) renewable energy niches, or new pathways....

  13. FEARCF a multidimensional free energy method for investigating conformational landscapes and chemical reaction mechanisms

    Institute of Scientific and Technical Information of China (English)

    NAIDOO Kevin J.

    2012-01-01

    The development and implementation of a computational method able to produce free energies in multiple dimensions,descriptively named the free energies from adaptive reaction coordinate forces (FEARCF) method is described in this paper.While the method can be used to calculate free energies of association,conformation and reactivity here it is shown in the context of chemical reaction landscapes.A reaction free energy surface for the Claisen rearrangement of chorismate to prephenate is used as an illustration of the method's efficient convergence.FEARCF simulations are shown to achieve fiat histograms for complex multidimensional free energy volumes.The sampling efficiency by which it produces multidimensional free energies is demonstrated on the complex puckering of a pyranose ring,that is described by a three dimensional W(θ1,θ2,θ3) potential of mean force.

  14. Ultrasonic Generators for Energy Harvesting Applications: Self-Excitation and Mechanical Frequency Transformation

    OpenAIRE

    Heffel, Eduard

    2013-01-01

    The main objective in the field of vibration-based energy harvesting is to convert the kinetic energy from an ambient energy source into an useable electrical form in the most efficient way. The intention is to provide power for low-powered electronic devices, such as intelligent sensors for structural health monitoring, in order to make an external power source or periodic battery replacement redundant and thus lower the costs. Applications of this technology can be found in the automotive a...

  15. Electric field induced phase transitions in polymers: a novel mechanism for high speed energy storage.

    Science.gov (United States)

    Ranjan, V; Nardelli, Marco Buongiorno; Bernholc, J

    2012-02-24

    Using first-principles simulations, we identify the microscopic origin of the nonlinear dielectric response and high energy density of polyvinylidene-fluoride-based polymers as a cooperative transition path that connects nonpolar and polar phases of the system. This path explores a complex torsional and rotational manifold and is thermodynamically and kinetically accessible at relatively low temperatures. Furthermore, the introduction of suitable copolymers significantly alters the energy barriers between phases providing tunability of both the energy density and the critical fields.

  16. Experimental free energy surfaces reveal the mechanisms of maintenance of protein solubility

    National Research Council Canada - National Science Library

    Alfonso De Simone; Anne Dhulesia; Gemma Soldi; Michele Vendruscolo; Shang-Te Danny Hsu; Fabrizio Chiti; Christopher M. Dobson

    2011-01-01

    .... We have determined a series of energy landscapes of the acylphosphatase from Drosophila melanogaster under a variety of conditions by combining NMR measurements with restrained molecular dynamics simulations...

  17. Evaluation of an Incremental Ventilation Energy Model for Estimating Impacts of Air Sealing and Mechanical Ventilation

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Jennifer M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Turner, Willliam JN [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-07-01

    Changing the rate of airflow through a home affects the annual thermal conditioning energy. Large-scale changes to airflow rates of the housing stock can significantly alter the energy consumption of the residential energy sector. However, the complexity of existing residential energy models hampers the ability to estimate the impact of policy changes on a state or nationwide level. The Incremental Ventilation Energy (IVE) model developed in this study was designed to combine the output of simple airflow models and a limited set of home characteristics to estimate the associated change in energy demand of homes. The IVE model was designed specifically to enable modelers to use existing databases of home characteristics to determine the impact of policy on ventilation at a population scale. In this report, we describe the IVE model and demonstrate that its estimates of energy change are comparable to the estimates of a wellvalidated, complex residential energy model when applied to homes with limited parameterization. Homes with extensive parameterization would be more accurately characterized by complex residential energy models. The demonstration included a range of home types, climates, and ventilation systems that cover a large fraction of the residential housing sector.

  18. SPRING Project on Mechanical Energy on Demand from High Strain Actuators

    Science.gov (United States)

    2009-09-02

    the U pol term in equation (4) is known to be ‘made of’ two parts: −U pol = −U polel +U pold , where U polel represents the magnitude of the potential...energy of the electron in the polarization field and U pold represents the energy required to create this polarization (‘deformation energy’); with the...optimal polarization, U pold = U polel /2. Both energy functionals (1) and (4) assume that the electron and hole energies are measured from the band

  19. Mammary gene expression profiles during an intramammary challenge reveal potential mechanisms linking negative energy balance with impaired immune response

    DEFF Research Database (Denmark)

    Moyes, Kasey; Drackley, J K; Morin, D E;

    2010-01-01

    Our objective was to compare mammary tissue gene expression profiles during a Streptococcus uberis (S. uberis) mastitis challenge between lactating cows subjected to dietary-induced negative energy balance (NEB; n = 5) and cows fed ad libitum to maintain positive energy balance (PEB; n = 5......) in order to better understand the mechanisms associated with NEB and risk of mastitis during the transition period. The NEB cows were feed-restricted to 60% of calculated net energy for lactation requirements for 7 d, and cows assigned to PEB were fed the same diet for ad libitum intake. Five days after...... feed restriction, one rear mammary quarter of each cow was inoculated with 5,000 cfu of S. uberis (O140J). At 20 h post-inoculation, S. uberis-infected mammary quarters from all cows were biopsied for RNA extraction. Energy balance (NEB vs. PEB) resulted in 287 differentially expressed genes (DEG; FDR...

  20. The Effect of Welding Energy on the Microstructural and Mechanical Properties of Ultrasonic-Welded Copper Joints

    Directory of Open Access Journals (Sweden)

    Jingwei Yang

    2017-02-01

    Full Text Available The effects of welding energy on the mechanical and microstructural characteristics of ultrasonic-welded pure copper plates were investigated. Complex dynamic recrystallization and grain growth occurred inside the weld zone during ultrasonic welding. At a low welding energy, a thin band of straight weld interfaces was observed and had an ultra-fine grain structure. With an increase in welding energy, the weld interface progressively changed from flat to sinusoidal, and eventually turned into a convoluted wavy pattern, bearing similarities to shear instabilities, as observed in fluid dynamics. The lap shear load of the joints initially increased and then remained stable as the welding energy increased. The tensile characteristics of the joints significantly depended on the development of plastic deformation at the interface. The influence of the microstructure on the hardness was also discussed.

  1. Delay Efficient Method for Delivering IPTV Services

    Directory of Open Access Journals (Sweden)

    Sangamesh

    2014-07-01

    Full Text Available Internet Protocol Television (IPTV is a system through which Internet television services are delivered using the architecture and networking methods of the Internet Protocol Suite over a packet-switched network infrastructure, e.g., the Internet and broadband Internet access networks, instead of being delivered through traditional radio frequency broadcast, satellite signal, and cable television (CATV formats. IPTV provides mainly three services: live TV, catch up TV, and video on demand (VoD.This paper focuses on delivering the live TV services by exploiting the virtualised cloud architecture of the IPTV and statistical multiplexing. The VoD tasks are prescheduled so that there will be less Instant Channel Change (ICC delay. We select a proper scheduling algorithm for rescheduling the VoD tasks. We then implement the scheduling algorithm for preshifting the VoD tasks.

  2. On the effectiveness of the thermoelectric energy filtering mechanism in low-dimensional superlattices and nano-composites

    Science.gov (United States)

    Thesberg, Mischa; Kosina, Hans; Neophytou, Neophytos

    2016-12-01

    Electron energy filtering has been suggested as a promising way to improve the power factor and enhance the ZT figure of merit of thermoelectric materials. In this work, we explore the effect that reduced dimensionality has on the success of the energy-filtering mechanism for power factor enhancement. We use the quantum mechanical non-equilibrium Green's function method for electron transport including electron-phonon scattering to explore 1D and 2D superlattice/nanocomposite systems. We find that, given identical material parameters, 1D channels utilize energy filtering more effectively than 2D as they: (i) allow one to achieve the maximal power factor for smaller well sizes/smaller grains which are needed to maximize the phonon scattering, (ii) take better advantage of a lower thermal conductivity in the barrier/boundary materials compared to the well/grain materials in both: enhancing the Seebeck coefficient; and in producing a system which is robust against detrimental random deviations from the optimal barrier design. In certain cases, we find that the relative advantage can be as high as a factor of 3. We determine that energy-filtering is most effective when the average energy of carrier flow varies the most between the wells and the barriers along the channel, an event which occurs when the energy of the carrier flow in the host material is low, and when the energy relaxation mean-free-path of carriers is short. Although the ultimate reason for these aspects, which cause a 1D system to see greater relative improvement than a 2D, is the 1D system's van Hove singularity in the density-of-states, the insights obtained are general and inform energy-filtering design beyond dimensional considerations.

  3. Potential Mechanisms for Microbial Energy Acquisition in Oxic Deep-Sea Sediments.

    Science.gov (United States)

    Tully, Benjamin J; Heidelberg, John F

    2016-07-15

    The South Pacific Gyre (SPG) possesses the lowest rates of sedimentation, surface chlorophyll concentration, and primary productivity in the global oceans. As a direct result, deep-sea sediments are thin and contain small amounts of labile organic carbon. It was recently shown that the entire SPG sediment column is oxygenated and may be representative of up to a third of the global marine environment. To understand the microbial processes that contribute to the removal of the labile organic matter at the water-sediment interface, a sediment sample was collected and subjected to metagenomic sequencing and analyses. Analysis of nine partially reconstructed environmental genomes, which represent approximately one-third of the microbial community, revealed that the members of the SPG surface sediment microbial community are phylogenetically distinct from surface/upper-ocean organisms. These genomes represent a wide distribution of novel organisms, including deep-branching Alphaproteobacteria, two novel organisms within the Proteobacteria, and new members of the Nitrospirae, Nitrospinae, and candidate phylum NC10. These genomes contain evidence for microbially mediated metal (iron/manganese) oxidation and carbon fixation linked to nitrification. Additionally, despite hypothesized energy limitation, members of the SPG microbial community had motility and chemotaxis genes and possessed mechanisms for the degradation of high-molecular-weight organic matter. This study contributes to our understanding of the metabolic potential of microorganisms in deep-sea oligotrophic sediments and their impact on local carbon geochemistry. This research provides insight into the microbial metabolic potential of organisms inhabiting oxygenated deep-sea marine sediments. Current estimates suggest that these environments account for up to a third of the global marine sediment habitat. Nine novel deep-sea microbial genomes were reconstructed from a metagenomic data set and expand the limited

  4. Mechanical effects induced by shock waves generated by high energy laser pulses

    Science.gov (United States)

    Fournier, J.; Ballard, P.; Merrien, P.; Barralis, J.; Castex, L.; Fabbro, R.

    1991-09-01

    Specimens made of low alloy and non alloyed medium carbon steels were subjected to high energy laser pulses. Direct ablation and confined plasma procedures were both investigated. An optimum impulse momentum transfer to the material is attained with a pulse duration of 30 ns and a power density of 10 GW .cm^2. Fatigue testing shows that the fatigue strengths of the selected materials are significantly increased. This can be related to the fact that laser shock processing generates an appropriate residual compressive stress field in a sufficiently thick layer and does not alter the initial surface roughness. In addition, the use of cumulative laser impacts and of dual treatment combining thermal and mechanical effects of the laser beam have been investigated and shown to result in an enhanced fatigue strength. Des échantillons d'acier éventuellement faiblement allié sont irradiés par un ou plusieurs pulses laser ayant une intensité comprise entre 1 et 100 GW/cm^2 et une durée d'émission laser de 3 ou 30 ns, les deux configurations d'ablation directe ou de plasma confiné étant utilisées. Les contraintes résiduelles résultant du passage de l'onde de choc sont analysées à l'aide de la technique de diffraction de rayons X. D'après cette étude, il apparaît clairement que les valeurs d'intensité et de durée d'émission laser les plus appropriées sont respectivement 10 GW/cm^2 et 30 ns. Ces valeurs correspondent à l'optimum de transfert d'impulsion. De plus, l'influence du nombre d'impacts laser utilisés est discuté et un essai de fatigue montre que ce traitement mécanique de surface augmente de manière significative la limite d'endurance du matériau étudié.

  5. Gating energies and forces of the mammalian hair cell transducer channel and related hair bundle mechanics

    NARCIS (Netherlands)

    van Netten, SM; Kros, CJ

    2000-01-01

    We quantified the molecular energies and forces involved in opening and closing of mechanoelectrical transducer channels in hair cells using a novel generally applicable method. It relies on a thermodynamic description of the free energy of an ion channel in terms of its open probability. The

  6. Thermodynamics of a tropical cyclone: generation and dissipation of mechanical energy in a self-driven convection system

    Directory of Open Access Journals (Sweden)

    Hisashi Ozawa

    2015-01-01

    Full Text Available The formation process of circulatory motion of a tropical cyclone is investigated from a thermodynamic viewpoint. The generation rate of mechanical energy by a fluid motion under diabatic heating and cooling, and the dissipation rate of this energy due to irreversible processes are formulated from the first and second laws of thermodynamics. This formulation is applied to a tropical cyclone, and the formation process of the circulatory motion is examined from a balance between the generation and dissipation rates of mechanical energy in the fluid system. We find from this formulation and data analysis that the thermodynamic efficiency of tropical cyclones is about 40% lower than the Carnot maximum efficiency because of the presence of thermal dissipation due to irreversible transport of sensible and latent heat in the atmosphere. We show that a tropical cyclone tends to develop within a few days through a feedback supply of mechanical energy when the sea surface temperature is higher than 300 K, and when the horizontal scale of circulation becomes larger than the vertical height of the troposphere. This result is consistent with the critical radius of 50 km and the corresponding central pressure of about 995 hPa found in statistical properties of typhoons observed in the western North Pacific.

  7. Non-Thermal Electron Acceleration in Low Mach Number Collisionless Shocks. I. Particle Energy Spectra and Acceleration Mechanism

    CERN Document Server

    Guo, Xinyi; Narayan, Ramesh

    2014-01-01

    Electron acceleration to non-thermal energies in low Mach number (M<5) shocks is revealed by radio and X-ray observations of galaxy clusters and solar flares, but the electron acceleration mechanism remains poorly understood. Diffusive shock acceleration, also known as first-order Fermi acceleration, cannot be directly invoked to explain the acceleration of electrons. Rather, an additional mechanism is required to pre-accelerate the electrons from thermal to supra-thermal energies, so they can then participate in the Fermi process. In this work, we use two- and three-dimensional particle-in-cell plasma simulations to study electron acceleration in low Mach number shocks. We focus on the particle energy spectra and the acceleration mechanism in a reference run with M=3. We find that about 15 percent of the electrons can be efficiently accelerated, forming a non-thermal power-law tail in the energy spectrum with a slope of p~2.4. Initially, thermal electrons are energized at the shock front via shock drift a...

  8. Non-thermal Electron Acceleration in Low Mach Number Collisionless Shocks. I. Particle Energy Spectra and Acceleration Mechanism

    Science.gov (United States)

    Guo, Xinyi; Sironi, Lorenzo; Narayan, Ramesh

    2014-10-01

    Electron acceleration to non-thermal energies in low Mach number (Ms Diffusive shock acceleration, also known as first-order Fermi acceleration, cannot be directly invoked to explain the acceleration of electrons. Rather, an additional mechanism is required to pre-accelerate the electrons from thermal to supra-thermal energies, so they can then participate in the Fermi process. In this work, we use two- and three-dimensional particle-in-cell plasma simulations to study electron acceleration in low Mach number shocks. We focus on the particle energy spectra and the acceleration mechanism in a reference run with Ms = 3 and a quasi-perpendicular pre-shock magnetic field. We find that about 15% of the electrons can be efficiently accelerated, forming a non-thermal power-law tail in the energy spectrum with a slope of p ~= 2.4. Initially, thermal electrons are energized at the shock front via shock drift acceleration (SDA). The accelerated electrons are then reflected back upstream where their interaction with the incoming flow generates magnetic waves. In turn, the waves scatter the electrons propagating upstream back toward the shock for further energization via SDA. In summary, the self-generated waves allow for repeated cycles of SDA, similarly to a sustained Fermi-like process. This mechanism offers a natural solution to the conflict between the bright radio synchrotron emission observed from the outskirts of galaxy clusters and the low electron acceleration efficiency usually expected in low Mach number shocks.

  9. A simplified model for estimating population-scale energy impacts of building envelope air-tightening and mechanical ventilation retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Logue, Jennifer M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Turner, William J. N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Trinity College Dublin, Dublin (Ireland); Walker, Iain S. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Singer, Brett C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-01-19

    Changing the air exchange rate of a home (the sum of the infiltration and mechanical ventilation airflow rates) affects the annual thermal conditioning energy. Large-scale changes to air exchange rates of the housing stock can significantly alter the residential sector's energy consumption. However, the complexity of existing residential energy models is a barrier to the accurate quantification of the impact of policy changes on a state or national level. The Incremental Ventilation Energy (IVE) model developed in this study combines the output of simple air exchange models with a limited set of housing characteristics to estimate the associated change in energy demand of homes. The IVE model was designed specifically to enable modellers to use existing databases of housing characteristics to determine the impact of ventilation policy change on a population scale. The IVE model estimates of energy change when applied to US homes with limited parameterisation are shown to be comparable to the estimates of a well-validated, complex residential energy model.

  10. Quantum mechanics capacitance molecular mechanics modeling of core-electron binding energies of methanol and methyl nitrite on Ag(111) surface

    Science.gov (United States)

    Löytynoja, T.; Li, X.; Jänkälä, K.; Rinkevicius, Z.; Ågren, H.

    2016-07-01

    We study a newly devised quantum mechanics capacitance molecular mechanics (QMCMM) method for the calculation of core-electron binding energies in the case of molecules adsorbed on metal surfaces. This yet untested methodology is applied to systems with monolayer of methanol/methyl nitrite on an Ag(111) surface at 100 K temperature. It was found out that the studied C, N, and O 1s core-hole energies converge very slowly as a function of the radius of the metallic cluster, which was ascribed to build up of positive charge on the edge of the Ag slab. Further analysis revealed that an extrapolation process can be used to obtain binding energies that deviated less than 0.5 eV against experiments, except in the case of methanol O 1s where the difference was as large as 1.8 eV. Additional QM-cluster calculations suggest that the latter error can be connected to the lack of charge transfer over the QM-CMM boundary. Thus, the results indicate that the QMCMM and QM-cluster methods can complement each other in a holistic picture of molecule-adsorbate core-ionization studies, where all types of intermolecular interactions are considered.

  11. Quantum mechanics capacitance molecular mechanics modeling of core-electron binding energies of methanol and methyl nitrite on Ag(111) surface.

    Science.gov (United States)

    Löytynoja, T; Li, X; Jänkälä, K; Rinkevicius, Z; Ågren, H

    2016-07-14

    We study a newly devised quantum mechanics capacitance molecular mechanics (QMCMM) method for the calculation of core-electron binding energies in the case of molecules adsorbed on metal surfaces. This yet untested methodology is applied to systems with monolayer of methanol/methyl nitrite on an Ag(111) surface at 100 K temperature. It was found out that the studied C, N, and O 1s core-hole energies converge very slowly as a function of the radius of the metallic cluster, which was ascribed to build up of positive charge on the edge of the Ag slab. Further analysis revealed that an extrapolation process can be used to obtain binding energies that deviated less than 0.5 eV against experiments, except in the case of methanol O 1s where the difference was as large as 1.8 eV. Additional QM-cluster calculations suggest that the latter error can be connected to the lack of charge transfer over the QM-CMM boundary. Thus, the results indicate that the QMCMM and QM-cluster methods can complement each other in a holistic picture of molecule-adsorbate core-ionization studies, where all types of intermolecular interactions are considered.

  12. Combined quantum mechanics/molecular mechanics (QM/MM) simulations for protein-ligand complexes: free energies of binding of water molecules in influenza neuraminidase.

    Science.gov (United States)

    Woods, Christopher J; Shaw, Katherine E; Mulholland, Adrian J

    2015-01-22

    The applicability of combined quantum mechanics/molecular mechanics (QM/MM) methods for the calculation of absolute binding free energies of conserved water molecules in protein/ligand complexes is demonstrated. Here, we apply QM/MM Monte Carlo simulations to investigate binding of water molecules to influenza neuraminidase. We investigate five different complexes, including those with the drugs oseltamivir and peramivir. We investigate water molecules in two different environments, one more hydrophobic and one hydrophilic. We calculate the free-energy change for perturbation of a QM to MM representation of the bound water molecule. The calculations are performed at the BLYP/aVDZ (QM) and TIP4P (MM) levels of theory, which we have previously demonstrated to be consistent with one another for QM/MM modeling. The results show that the QM to MM perturbation is significant in both environments (greater than 1 kcal mol(-1)) and larger in the more hydrophilic site. Comparison with the same perturbation in bulk water shows that this makes a contribution to binding. The results quantify how electronic polarization differences in different environments affect binding affinity and also demonstrate that extensive, converged QM/MM free-energy simulations, with good levels of QM theory, are now practical for protein/ligand complexes.

  13. Interlimb relation during the double support phase of gait: an electromyographic, mechanical and energy-based analysis.

    Science.gov (United States)

    Sousa, Andreia S P; Silva, Augusta; Tavares, João Manuel R S

    2013-03-01

    The purpose of this study is to analyse the interlimb relation and the influence of mechanical energy on metabolic energy expenditure during gait. In total, 22 subjects were monitored as to electromyographic activity, ground reaction forces and VO2 consumption (metabolic power) during gait. The results demonstrate a moderate negative correlation between the activity of tibialis anterior, biceps femoris and vastus medialis of the trailing limb during the transition between mid-stance and double support and that of the leading limb during double support for the same muscles, and between these and gastrocnemius medialis and soleus of the trailing limb during double support. Trailing limb soleus during the transition between mid-stance and double support was positively correlated to leading limb tibialis anterior, vastus medialis and biceps femoris during double support. Also, the trailing limb centre of mass mechanical work was strongly influenced by the leading limbs, although only the mechanical power related to forward progression of both limbs was correlated to metabolic power. These findings demonstrate a consistent interlimb relation in terms of electromyographic activity and centre of mass mechanical work, being the relations occurred in the plane of forward progression the more important to gait energy expenditure.

  14. Energy-Saving Study of a System for Ammonium Sulfate Recovery from Wastewater with Mechanical Vapor Compression (MVC

    Directory of Open Access Journals (Sweden)

    Lin Liang

    2011-11-01

    Full Text Available In this study, a new two stage Mechanical Vapor Compression (MVC system which is used to recycle ammonium sulfate is investigated. In evaporation process, there are many efficient ways such as multiple-effect evaporation, multi-stage flash, thermal vapor compression, and mechanical vapor compression and so on. In these ways MVC is considered to be more effective. Now, almost all of the MVC systems in the literatures are about one stage structure. However, in the other process such as continuous crystallizer, if one stage MVC system is adopted, a lot of energy will be wasted. Therefore, in order to further save energy, a new system should be proposed. In this study, a new two stage MVC system is proposed and analyzed using the software of ASPEN PLUS. The first stage is a forcible recycle evaporator with MVC and the second one is a forcible recycle crystallizer with MVC. The energy consumption is discussed as a function of the middle concentration and the operating temperature. The results show that the compressor power decreases with the increase in the operating temperature and the optimal compressor power is obtained when the mass concentration is about 32%. Compared with one stage MVC system the running cost of the new system can be saved 29.2% and more than 25.8% of the energy can be saved. Additionally, it can save running cost over 42.2% and save energy more than 59.6% compared with the conventional multi-effect system.

  15. Influencing Mechanism Analysis of Holiday Activity–Travel Patterns on Transportation Energy Consumption and Emissions in China

    Directory of Open Access Journals (Sweden)

    Bobin Wang

    2017-07-01

    Full Text Available Energy shortage and atmospheric pollution problems are getting more serious in China, and transportation is the main source of energy consumption, pollutants, and carbon emissions. This study combined the activity-based analysis method with emission models, and investigated the influence mechanism of people’s activity travel scheduling on transportation energy consumption and emissions on holidays. Based on the holiday travel behavior survey data, the multinomial logistic regression model was first applied to explore the decision mechanisms of individual travel-mode choices in holidays. Next, the emission model was integrated with an activity-based travel demand model to calculate and compare transportation energy consumption and emissions under different policy scenarios. The results showed that socio-demographic characteristics had significant effects on holiday activity–travel patterns, and combined mode chains had a larger number of activity points than single mode chains. With an increase in the trip time of cars, and decrease of travel distance and the number of activity points, transportation energy consumption and emissions could be reduced greatly with an adjustment of holiday activity–travel patterns. The reduced portion is mainly attracted by slow traffic and public transport. However, the effects of a single policy strategy are very limited, thus portfolio policies need to be considered by policy makers.

  16. The effect of mechanical twisting on oxygen ionic transport in solid-state energy conversion membranes.

    Science.gov (United States)

    Shi, Yanuo; Bork, Alexander Hansen; Schweiger, Sebastian; Rupp, Jennifer Lilia Marguerite

    2015-07-01

    Understanding 'electro-chemo-mechanics' in oxygen ion conducting membranes represents a foundational step towards new energy devices such as micro fuel cells and oxygen or fuel separation membranes. For ionic transport in macro crystalline electrolytes, doping is conventionally used to affect oxygen ionic association/migration energies. Recently, tuning ionic transport in films through lattice strain conveyed by substrates or heterostructures has generated much interest. However, reliable manipulation of strain states to twist the ionic conduction in real micro energy devices remains intractable. Here, we demonstrate that the oxygen ionic conductivity clearly correlates with the compressive strain energy acting on the near order of the electrolyte lattices by comparing thin-film ceria-based membrane devices against substrate-supported flat structures. It is possible to capitalize on this phenomenon with a smart choice of strain patterns achieved through microelectrode design. We highlight the importance of electro-chemo-mechanics in the electrolyte material for the next generation of solid-state energy conversion microdevices.

  17. TOPICAL REVIEW: Measuring the energy landscape roughness and the transition state location of biomolecules using single molecule mechanical unfolding experiments

    Science.gov (United States)

    Hyeon, Changbong; Thirumalai, D.

    2007-03-01

    Single molecule mechanical unfolding experiments are beginning to provide profiles of the complex energy landscape of biomolecules. In order to obtain reliable estimates of the energy landscape characteristics it is necessary to combine the experimental measurements (the force-extension curves, the mechanical unfolding trajectories, force or loading rate dependent unfolding rates) with sound theoretical models and simulations. Here, we show how by using temperature as a variable in mechanical unfolding of biomolecules in laser optical tweezer or AFM experiments the roughness of the energy landscape can be measured without making any assumptions about the underlying reaction coordinate. The efficacy of the formalism is illustrated by reviewing experimental results that have directly measured roughness in a protein-protein complex. The roughness model can also be used to interpret experiments on forced unfolding of proteins in which temperature is varied. Estimates of other aspects of the energy landscape such as free energy barriers or the transition state (TS) locations could depend on the precise model used to analyse the experimental data. We illustrate the inherent difficulties in obtaining the transition state location from loading rate or force dependent unfolding rates. Because the transition state moves as the force or the loading rate is varied it is in general difficult to invert the experimental data unless the curvature at the top of the one dimensional free energy profile is large, i.e. the barrier is sharp. The independence of the TS location of the force holds good only for brittle or hard biomolecules whereas the TS location changes considerably if the molecule is soft or plastic. We also comment on the usefulness of extension of the molecule as a surrogate reaction coordinate especially in the context of force-quench refolding of proteins and RNA.

  18. Direct measures of mechanical energy for knife mill size reduction of switchgrass, wheat straw, and corn stover.

    Science.gov (United States)

    Bitra, Venkata S P; Womac, Alvin R; Igathinathane, C; Miu, Petre I; Yang, Yuechuan T; Smith, David R; Chevanan, Nehru; Sokhansanj, Shahab

    2009-12-01

    Lengthy straw/stalk of biomass may not be directly fed into grinders such as hammer mills and disc refiners. Hence, biomass needs to be preprocessed using coarse grinders like a knife mill to allow for efficient feeding in refiner mills without bridging and choking. Size reduction mechanical energy was directly measured for switchgrass (Panicum virgatum L.), wheat straw (Triticum aestivum L.), and corn stover (Zea mays L.) in an instrumented knife mill. Direct power inputs were determined for different knife mill screen openings from 12.7 to 50.8 mm, rotor speeds between 250 and 500 rpm, and mass feed rates from 1 to 11 kg/min. Overall accuracy of power measurement was calculated to be +/-0.003 kW. Total specific energy (kWh/Mg) was defined as size reduction energy to operate mill with biomass. Effective specific energy was defined as the energy that can be assumed to reach the biomass. The difference is parasitic or no-load energy of mill. Total specific energy for switchgrass, wheat straw, and corn stover chopping increased with knife mill speed, whereas, effective specific energy decreased marginally for switchgrass and increased for wheat straw and corn stover. Total and effective specific energy decreased with an increase in screen size for all the crops studied. Total specific energy decreased with increase in mass feed rate, but effective specific energy increased for switchgrass and wheat straw, and decreased for corn stover at increased feed rate. For knife mill screen size of 25.4 mm and optimum speed of 250 rpm, optimum feed rates were 7.6, 5.8, and 4.5 kg/min for switchgrass, wheat straw, and corn stover, respectively, and the corresponding total specific energies were 7.57, 10.53, and 8.87 kWh/Mg and effective specific energies were 1.27, 1.50, and 0.24 kWh/Mg for switchgrass, wheat straw, and corn stover, respectively. Energy utilization ratios were calculated as 16.8%, 14.3%, and 2.8% for switchgrass, wheat straw, and corn stover, respectively. These

  19. A One-Structure-Based Hybridized Nanogenerator for Scavenging Mechanical and Thermal Energies by Triboelectric-Piezoelectric-Pyroelectric Effects.

    Science.gov (United States)

    Wang, Shuhua; Wang, Zhong Lin; Yang, Ya

    2016-04-20

    A hybridized nanogenerator is demonstrated, which has the structure of PVDF nanowires-PDMS composite film/indium tin oxide (ITO) electrode/polarized PVDF film/ITO electrode, and which can individually/simultaneously scavenge mechanical and thermal energies using piezoelectric, triboelectric, and pyroelectric effects. As compared with the individual energy harvesting unit, the hybridized nanogenerator has a much better charging performance. This work may push forward a significant step toward multienergy harvesting technology. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Orbital rotation without orbital angular momentum: mechanical action of the spin part of the internal energy flow in light beams

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Bekshaev, A. Ya; Maksimyak, P. P.

    2012-01-01

    The internal energy flow in a light beam can be divided into the "orbital" and "spin" parts, associated with the spatial and polarization degrees of freedom of light. In contrast to the orbital one, experimental observation of the spin flow seems problematic because it is converted into an orbital...... particles within a field where the transverse energy circulation is associated exclusively with the spin flow. This result can be treated as the first demonstration of mechanical action of the spin flow of a light field....