WorldWideScience

Sample records for underlying energy landscape

  1. Research using energy landscape

    International Nuclear Information System (INIS)

    Kim, Hack Jin

    2007-01-01

    Energy landscape is a theoretical tool used for the study of systems where cooperative processes occur such as liquid, glass, clusters, and protein. Theoretical and experimental researches related to energy landscape are introduced in this review

  2. Evolution under Drug Pressure Remodels the Folding Free-Energy Landscape of Mature HIV-1 Protease.

    Science.gov (United States)

    Louis, John M; Roche, Julien

    2016-07-03

    Using high-pressure NMR spectroscopy and differential scanning calorimetry, we investigate the folding landscape of the mature HIV-1 protease homodimer. The cooperativity of unfolding was measured in the absence or presence of a symmetric active site inhibitor for the optimized wild type protease (PR), its inactive variant PRD25N, and an extremely multidrug-resistant mutant, PR20. The individual fit of the pressure denaturation profiles gives rise to first order, ∆GNMR, and second order, ∆VNMR (the derivative of ∆GNMR with pressure); apparent thermodynamic parameters for each amide proton considered. Heterogeneity in the apparent ∆VNMR values reflects departure from an ideal cooperative unfolding transition. The narrow to broad distribution of ∆VNMR spanning the extremes from inhibitor-free PR20D25N to PR-DMP323 complex, and distinctively for PRD25N-DMP323 complex, indicated large variations in folding cooperativity. Consistent with this data, the shape of thermal unfolding transitions varies from asymmetric for PR to nearly symmetric for PR20, as dimer-inhibitor ternary complexes. Lack of structural cooperativity was observed between regions located close to the active site, including the hinge and tip of the glycine-rich flaps, and the rest of the protein. These results strongly suggest that inhibitor binding drastically decreases the cooperativity of unfolding by trapping the closed flap conformation in a deep energy minimum. To evade this conformational trap, PR20 evolves exhibiting a smoother folding landscape with nearly an ideal two-state (cooperative) unfolding transition. This study highlights the malleability of retroviral protease folding pathways by illustrating how the selection of mutations under drug pressure remodels the free-energy landscape as a primary mechanism. Published by Elsevier Ltd.

  3. Genomic Energy Landscapes.

    Science.gov (United States)

    Zhang, Bin; Wolynes, Peter G

    2017-02-07

    Energy landscape theory, developed in the context of protein folding, provides, to our knowledge, a new perspective on chromosome architecture. We review what has been learned concerning the topology and structure of both the interphase and mitotic chromosomes from effective energy landscapes constructed using Hi-C data. Energy landscape thinking raises new questions about the nonequilibrium dynamics of the chromosome and gene regulation. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  4. Monitoring Forest Change in Landscapes Under-Going Rapid Energy Development: Challenges and New Perspectives

    Directory of Open Access Journals (Sweden)

    Paul D. Pickell

    2014-07-01

    Full Text Available The accelerated development of energy resources around the world has substantially increased forest change related to oil and gas activities. In some cases, oil and gas activities are the primary catalyst of land-use change in forested landscapes. We discuss the challenges associated with characterizing ecological change related to energy resource development using North America as an exemplar. We synthesize the major impacts of energy development to forested ecosystems and offer new perspectives on how to detect and monitor anthropogenic disturbance during the Anthropocene. The disturbance of North American forests for energy development has resulted in persistent linear corridors, suppression of historical disturbance regimes, novel ecosystems, and the eradication of ecological memory. Characterizing anthropogenic disturbances using conventional patch-based disturbance measures will tend to underestimate the ecological impacts of energy development. Suitable indicators of anthropogenic impacts in forests should be derived from the integration of multi-scalar Earth observations. Relating these indicators to ecosystem condition will be a capstone in the progress toward monitoring forest change in landscapes undergoing rapid energy development.

  5. Energy landscape Allgaeu; Energielandschaft Allgaeu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-04-01

    In tandems with questions on the energy policy turnaround, the topics cultural landscape history, morphology, actual land use, tourism, settlement development or infrastructure are summarized in regional concepts and designs to a consistent landscape. Thus, a true integration of renewable energies in the landscape enhances existing or creates completely new landscape qualities. Energy supply shall be understood as a component of the every day life world. The energy supply shall not be hidden any more, but it rather should be communicated as the brand 'Allgaeu'.

  6. Energy landscapes and persistent minima

    Energy Technology Data Exchange (ETDEWEB)

    Carr, Joanne M.; Wales, David J., E-mail: dw34@cam.ac.uk [University Chemical Laboratories, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Mazauric, Dorian; Cazals, Frédéric, E-mail: frederic.cazals@inria.fr [Inria Sophia Antipolis Méditerranée, 2004 route des Lucioles, F-06902 Sophia Antipolis (France)

    2016-02-07

    We consider a coarse-graining of high-dimensional potential energy landscapes based upon persistences, which correspond to lowest barrier heights to lower-energy minima. Persistences can be calculated efficiently for local minima in kinetic transition networks that are based on stationary points of the prevailing energy landscape. The networks studied here represent peptides, proteins, nucleic acids, an atomic cluster, and a glassy system. Minima with high persistence values are likely to represent some form of alternative structural morphology, which, if appreciably populated at the prevailing temperature, could compete with the global minimum (defined as infinitely persistent). Threshold values on persistences (and in some cases equilibrium occupation probabilities) have therefore been used in this work to select subsets of minima, which were then analysed to see how well they can represent features of the full network. Simplified disconnectivity graphs showing only the selected minima can convey the funnelling (including any multiple-funnel) characteristics of the corresponding full graphs. The effect of the choice of persistence threshold on the reduced disconnectivity graphs was considered for a system with a hierarchical, glassy landscape. Sets of persistent minima were also found to be useful in comparing networks for the same system sampled under different conditions, using minimum oriented spanning forests.

  7. Energy landscapes in a crowded world

    NARCIS (Netherlands)

    Pasqualetti, Martin; Stremke, Sven

    2018-01-01

    One of the main drivers of landscape transformation has been our demand for energy. We refer to the results of such transformations as "energy landscapes". This paper examines the definition of energy landscapes within a conceptual framework, proposes a classification of energy landscapes, and

  8. Energy Landscape of Social Balance

    Science.gov (United States)

    Marvel, Seth A.; Strogatz, Steven H.; Kleinberg, Jon M.

    2009-11-01

    We model a close-knit community of friends and enemies as a fully connected network with positive and negative signs on its edges. Theories from social psychology suggest that certain sign patterns are more stable than others. This notion of social “balance” allows us to define an energy landscape for such networks. Its structure is complex: numerical experiments reveal a landscape dimpled with local minima of widely varying energy levels. We derive rigorous bounds on the energies of these local minima and prove that they have a modular structure that can be used to classify them.

  9. Graph representation of protein free energy landscape

    International Nuclear Information System (INIS)

    Li, Minghai; Duan, Mojie; Fan, Jue; Huo, Shuanghong; Han, Li

    2013-01-01

    The thermodynamics and kinetics of protein folding and protein conformational changes are governed by the underlying free energy landscape. However, the multidimensional nature of the free energy landscape makes it difficult to describe. We propose to use a weighted-graph approach to depict the free energy landscape with the nodes on the graph representing the conformational states and the edge weights reflecting the free energy barriers between the states. Our graph is constructed from a molecular dynamics trajectory and does not involve projecting the multi-dimensional free energy landscape onto a low-dimensional space defined by a few order parameters. The calculation of free energy barriers was based on transition-path theory using the MSMBuilder2 package. We compare our graph with the widely used transition disconnectivity graph (TRDG) which is constructed from the same trajectory and show that our approach gives more accurate description of the free energy landscape than the TRDG approach even though the latter can be organized into a simple tree representation. The weighted-graph is a general approach and can be used on any complex system

  10. Renewable energy from urban landscapes

    Science.gov (United States)

    Utilizing biomass from urban landscapes could significantly contribute to the nation’s renewable energy needs. In 2007, an experiment was begun to evaluate the biomass potential from a bermudagrass, Cynodon dactylon var. dactylon (L.) Pers., lawn in Woodward, OK and to estimate the potential biomas...

  11. Energy landscapes shape animal movement ecology.

    Science.gov (United States)

    Shepard, Emily L C; Wilson, Rory P; Rees, W Gareth; Grundy, Edward; Lambertucci, Sergio A; Vosper, Simon B

    2013-09-01

    The metabolic costs of animal movement have been studied extensively under laboratory conditions, although frequently these are a poor approximation of the costs of operating in the natural, heterogeneous environment. Construction of "energy landscapes," which relate animal locality to the cost of transport, can clarify whether, to what extent, and how movement properties are attributable to environmental heterogeneity. Although behavioral responses to aspects of the energy landscape are well documented in some fields (notably, the selection of tailwinds by aerial migrants) and scales (typically large), the principles of the energy landscape extend across habitat types and spatial scales. We provide a brief synthesis of the mechanisms by which environmentally driven changes in the cost of transport can modulate the behavioral ecology of animal movement in different media, develop example cost functions for movement in heterogeneous environments, present methods for visualizing these energy landscapes, and derive specific predictions of expected outcomes from individual- to population- and species-level processes. Animals modulate a suite of movement parameters (e.g., route, speed, timing of movement, and tortuosity) in relation to the energy landscape, with the nature of their response being related to the energy savings available. Overall, variation in movement costs influences the quality of habitat patches and causes nonrandom movement of individuals between them. This can provide spatial and/or temporal structure to a range of population- and species-level processes, ultimately including gene flow. Advances in animal-attached technology and geographic information systems are opening up new avenues for measuring and mapping energy landscapes that are likely to provide new insight into their influence in animal ecology.

  12. Energy transition: towards landscape devastation?

    International Nuclear Information System (INIS)

    Posokhow, Andre

    2013-09-01

    The author criticizes some aspects of the content of the French policy for energy transition. He states that the objective of reduction of greenhouse emissions is unreachable and moreover useless when China keeps on opening new coal-fired power stations. He states that temperatures do not increase any longer and that it is not sure that CO 2 emissions are responsible for past increases. He outlines that the power of wind turbines is only a quarter of their theoretical one, that replacing nuclear energy by wind energy would require the installation of 33.000 wind turbines. He states that objectives of energy saving are not credible, and that the energy mix predictions are fuzzy. He outlines contradictions about the nuclear power station life duration, states that the installation of 210 wind turbines per district would devastate the French landscape

  13. Energy forest cultivation and the landscape

    International Nuclear Information System (INIS)

    Bell, Simon

    1994-01-01

    The place of energy forestry in the landscape is discussed, principally with reference to Britain and Europe. The importance of design as a means of ensuring an attractive appearance, while meeting functional and economic requirements, is stressed. Simple design principles which help energy forests, mainly short rotation arable coppice, to fit into the landscape are suggested. (author)

  14. Sustainable energy landscapes : designing, planning, and development

    NARCIS (Netherlands)

    Stremke, S.; Dobbelsteen, van den A.

    2013-01-01

    In the near future the appearance and spatial organization of urban and rural landscapes will be strongly influenced by the generation of renewable energy. One of the critical tasks will be the re-integration of these sustainable energy landscapes into the existing environment—which people value and

  15. Energy landscapes, landscapes in transition. How to prepare one's territory to the deployment of renewable energies

    International Nuclear Information System (INIS)

    2014-06-01

    This guide first defines the notion of landscape, outlines what is at stake with decentralised renewable energy production, and presents the various important aspects of a deployment of decentralised renewable energy production. It describes how to define a general strategy for the integration of this production: relationship between energy and landscape, project implementation, partnership, tools to anticipate changes, evolution of social demand through dialogue, conciliation of technical and financial constraints and landscape ambitions. An appendix proposes legal and bibliographical information: legal relationships between energy and landscape, possible arrangements for PLU (plan local d'urbanisme, local urban plan) and SCOT (schema de coherence territoriale, territorial planning document)

  16. The renewable energies: the landscape

    International Nuclear Information System (INIS)

    Acket, C.; Bacher, P.

    2005-03-01

    If one takes into account the hydroelectric power, the France is the first european country in the renewable energies domain. The position is also honorable concerning the wood energy. Meanwhile, for the solar and wind energy, France is late. To discuss this debate, the authors bring together today data on the renewable energies, offer some proposals for the next 50 years taking into account the reduction of greenhouse gases emission for 2050. (A.L.B.)

  17. Visualizing energy landscapes with metric disconnectivity graphs.

    Science.gov (United States)

    Smeeton, Lewis C; Oakley, Mark T; Johnston, Roy L

    2014-07-30

    The visualization of multidimensional energy landscapes is important, providing insight into the kinetics and thermodynamics of a system, as well the range of structures a system can adopt. It is, however, highly nontrivial, with the number of dimensions required for a faithful reproduction of the landscape far higher than can be represented in two or three dimensions. Metric disconnectivity graphs provide a possible solution, incorporating the landscape connectivity information present in disconnectivity graphs with structural information in the form of a metric. In this study, we present a new software package, PyConnect, which is capable of producing both disconnectivity graphs and metric disconnectivity graphs in two or three dimensions. We present as a test case the analysis of the 69-bead BLN coarse-grained model protein and show that, by choosing appropriate order parameters, metric disconnectivity graphs can resolve correlations between structural features on the energy landscape with the landscapes energetic and kinetic properties. Copyright © 2014 The Authors Journal of Computational Chemistry Published by Wiley Periodicals, Inc.

  18. Exploring the conformational energy landscape of proteins

    Energy Technology Data Exchange (ETDEWEB)

    Nienhaus, G.U. [Univ. of Illinois, Urbana, IL (United States)]|[Universitaet Ulm (Germany); Mueller, J.D.; McMahon, B.H. [Univ. of Illinois, Urbana, IL (United States)] [and others

    1997-04-01

    Proteins possess a complex energy landscape with a large number of local minima called conformational substates that are arranged in a hierarchical fashion. Here we discuss experiments aimed at the elucidation of the energy landscape in carbonmonoxy myoglobin (MbCO). In the highest tier of the hierarchy, a few taxonomic substates exist. Because of their small number, these substates are accessible to detailed structural investigations. Spectroscopic experiments are discussed that elucidate the role of protonations of amino acid side chains in creating the substates. The lower tiers of the hierarchy contain a large number of statistical substates. Substate interconversions are observed in the entire temperature range from below 1 K up to the denaturation temperature, indicating a wide spectrum of energy barriers that separate the substates.

  19. Conformational motions in the rugged energy landscape of proteins

    Science.gov (United States)

    Nienhaus, G. Ulrich

    1999-10-01

    Under physiological conditions, proteins continuously fluctuate among a large number of conformational substates which can be represented by local minima in a multidimensional potential energy landscape. The complex topography of the landscape gives rise to an extremely broad distribution of characteristic times for conformational motions, spanning more than fifteen orders of magnitude, from fast bond librations to slow global unfolding. Here we focus on motions occurring on time scales larger than microseconds, which are particularly relevant to biomolecular function. For carbon-monoxy myoglobin, the photosynthetic reaction center of purple bacteria, and bovine pancreatic trypsin inhibitor, large-scale conformational changes have been measured over a wide temperature range. In all three cases, the rate coefficients governing the slow conformational changes depend strongly on temperature, and the dynamics can be understood with a model that assumes diffusional motions on a rugged energy land-scape with a random amplitude distribution around an average of about 10 kJ/mol.

  20. The changing geopolitical landscape of energy

    International Nuclear Information System (INIS)

    Lesourne, Jacques

    2011-08-01

    The author first discusses the impact of the financial crisis of 2008, and of the large-scale exploitation of shale gases in the USA on energy policies and on the geopolitical landscape of energy. Then, he discusses the influence that events which occurred in 2011 had on these issues: firstly, the Copenhagen and Cancun Conferences, secondly, the Fukushima accident, thirdly, the nuclear phasing-out by Germany and incidentally by Italy, and fourthly, the Arab Spring. In the next parts, he comments the consequences for the European energy policy, and the perspectives for the struggle against climate change

  1. Urban landscape architecture design under the view of sustainable development

    Science.gov (United States)

    Chen, WeiLin

    2017-08-01

    The concept of sustainable development in modern city landscape design advocates landscape architecture, which is the main development direction in the field of landscape design. They are also effective measures to promote the sustainable development of city garden. Based on this, combined with the connotation of sustainable development and sustainable design, this paper analyzes and discusses the design of urban landscape under the concept of sustainable development.

  2. Energy-landscape Nexus: Advancing a conceptual framework for the design of sustainable energy landscapes

    NARCIS (Netherlands)

    Stremke, S.

    2013-01-01

    For some time now, the concept of “energy landscape” is discussed in academia while more and more practising landscape architects contribute to the siting, designing, and assessment of renewable energy technologies (see Stremke et al. 2012). Yet, there remains some ambiguity what exactly is meant

  3. Observations on rate theory for rugged energy landscapes.

    Science.gov (United States)

    Pollak, Eli; Auerbach, Anthony; Talkner, Peter

    2008-11-01

    The potential energy profile for many complex reactions of proteins, such as folding or allosteric conformational change, involves many different scales of molecular motion along the reaction coordinate. Although it is natural to model the dynamics of motion along such rugged energy landscapes as diffusional (the Smoluchowski equation; SE), problems arise because the frictional forces generated by the molecular surround are typically not strong enough to justify the use of the SE. Here, we discuss the fundamental theory behind the SE and note that it may be justified through a master equation when reduced to its continuum limit. However, the SE cannot be used for rough energy landscapes, where the continuum limit is ill defined. Instead, we suggest that one should use a mean first passage time expression derived from a master equation, and show how this approach can be used to glean information about the underlying dynamics of barrier crossing. We note that the potential profile in the SE is that of the microbarriers between conformational substates, and that there is a temperature-dependent, effective friction associated with the long residence time in the microwells that populate the rough landscape. The number of recrossings of the overall barrier is temperature-dependent, governed by the microbarriers and not by the effective friction. We derive an explicit expression for the mean number of recrossings and its temperature dependence. Finally, we note that the mean first passage time can be used as a departure point for measuring the roughness of the landscape.

  4. Fairy circle landscapes under the sea

    KAUST Repository

    Ruiz-Reynés, Daniel

    2017-08-03

    Short-scale interactions yield large-scale vegetation patterns that, in turn, shape ecosystem function across landscapes. Fairy circles, which are circular patches bare of vegetation within otherwise continuous landscapes, are characteristic features of semiarid grasslands. We report the occurrence of submarine fairy circle seascapes in seagrass meadows and propose a simple model that reproduces the diversity of seascapes observed in these ecosystems as emerging from plant interactions within the meadow. These seascapes include two extreme cases, a continuous meadow and a bare landscape, along with intermediate states that range from the occurrence of persistent but isolated fairy circles, or solitons, to seascapes with multiple fairy circles, banded vegetation, and

  5. New interaction paths in the energy landscape: the role of local energy initiatives

    OpenAIRE

    de Boer, Jessica; Zuidema, Christian; Gugerell, Katharina

    2018-01-01

    Energy transition is an encompassing process which not only involves the energy system but also the landscape in which the energy system is embedded. Renewable energy is triggering new interactions with local landscapes in physical, socio-economic and institutional senses. We capture these interactions using the energy landscape concept, which expresses the interdependence of the energy system with the landscape. We aim to understand whether and how local energy initiatives facilitate this in...

  6. Designing misfolded proteins by energy landscaping.

    Science.gov (United States)

    Bhattacherjee, Arnab; Biswas, Parbati

    2011-01-13

    Conformational fluctuations in the native state ensemble enhance the complexity in designing de novo protein sequences that may fold correctly into a desired target structure. In this work, the results of a self-consistent mean field theory are applied to a cubic lattice model of proteins and real nonhomologous proteins to assess the designability of folded, misfolded, and unfolded conformations. This theory, for the first time, accounts for the properties of misfolded sequences in terms of a generalized foldability criterion and characterizes the topography of the sequence energy landscape in terms of folded, misfolded, and unfolded ensemble of conformations. For a given foldability criterion, the folded, misfolded, and unfolded conformations may be distinctly classified by tuning the energy variance of the native state ensemble. This implies a promising route to de novo protein design and provides useful insights into understanding the impact of conformational similarity/diversity on the folding-misfolding-unfolding transition.

  7. Madagascar's open landscapes under the spotlight

    African Journals Online (AJOL)

    pharmaceuticals, and emblematic landscapes for tourism. This special issue consists of six contributions ... Switzerland. Indian Ocean e-Ink. Promoting African Publishing and Education www.ioeink.com. Missouri Botanical Garden (MBG). Madagascar Research and Conservation Program. BP 3391. Antananarivo, 1 01 , ...

  8. Energy landscape analysis of neuroimaging data

    Science.gov (United States)

    Ezaki, Takahiro; Watanabe, Takamitsu; Ohzeki, Masayuki; Masuda, Naoki

    2017-05-01

    Computational neuroscience models have been used for understanding neural dynamics in the brain and how they may be altered when physiological or other conditions change. We review and develop a data-driven approach to neuroimaging data called the energy landscape analysis. The methods are rooted in statistical physics theory, in particular the Ising model, also known as the (pairwise) maximum entropy model and Boltzmann machine. The methods have been applied to fitting electrophysiological data in neuroscience for a decade, but their use in neuroimaging data is still in its infancy. We first review the methods and discuss some algorithms and technical aspects. Then, we apply the methods to functional magnetic resonance imaging data recorded from healthy individuals to inspect the relationship between the accuracy of fitting, the size of the brain system to be analysed and the data length. This article is part of the themed issue `Mathematical methods in medicine: neuroscience, cardiology and pathology'.

  9. Improved free-energy landscape reconstruction of bacteriorhodopsin highlights local variations in unfolding energy.

    Science.gov (United States)

    Heenan, Patrick R; Yu, Hao; Siewny, Matthew G W; Perkins, Thomas T

    2018-03-28

    Precisely quantifying the energetics that drive the folding of membrane proteins into a lipid bilayer remains challenging. More than 15 years ago, atomic force microscopy (AFM) emerged as a powerful tool to mechanically extract individual membrane proteins from a lipid bilayer. Concurrently, fluctuation theorems, such as the Jarzynski equality, were applied to deduce equilibrium free energies (ΔG 0 ) from non-equilibrium single-molecule force spectroscopy records. The combination of these two advances in single-molecule studies deduced the free-energy of the model membrane protein bacteriorhodopsin in its native lipid bilayer. To elucidate this free-energy landscape at a higher resolution, we applied two recent developments. First, as an input to the reconstruction, we used force-extension curves acquired with a 100-fold higher time resolution and 10-fold higher force precision than traditional AFM studies of membrane proteins. Next, by using an inverse Weierstrass transform and the Jarzynski equality, we removed the free energy associated with the force probe and determined the molecular free-energy landscape of the molecule under study, bacteriorhodopsin. The resulting landscape yielded an average unfolding free energy per amino acid (aa) of 1.0 ± 0.1 kcal/mol, in agreement with past single-molecule studies. Moreover, on a smaller spatial scale, this high-resolution landscape also agreed with an equilibrium measurement of a particular three-aa transition in bacteriorhodopsin that yielded 2.7 kcal/mol/aa, an unexpectedly high value. Hence, while average unfolding ΔG 0 per aa is a useful metric, the derived high-resolution landscape details significant local variation from the mean. More generally, we demonstrated that, as anticipated, the inverse Weierstrass transform is an efficient means to reconstruct free-energy landscapes from AFM data.

  10. Improved free-energy landscape reconstruction of bacteriorhodopsin highlights local variations in unfolding energy

    Science.gov (United States)

    Heenan, Patrick R.; Yu, Hao; Siewny, Matthew G. W.; Perkins, Thomas T.

    2018-03-01

    Precisely quantifying the energetics that drive the folding of membrane proteins into a lipid bilayer remains challenging. More than 15 years ago, atomic force microscopy (AFM) emerged as a powerful tool to mechanically extract individual membrane proteins from a lipid bilayer. Concurrently, fluctuation theorems, such as the Jarzynski equality, were applied to deduce equilibrium free energies (ΔG0) from non-equilibrium single-molecule force spectroscopy records. The combination of these two advances in single-molecule studies deduced the free-energy of the model membrane protein bacteriorhodopsin in its native lipid bilayer. To elucidate this free-energy landscape at a higher resolution, we applied two recent developments. First, as an input to the reconstruction, we used force-extension curves acquired with a 100-fold higher time resolution and 10-fold higher force precision than traditional AFM studies of membrane proteins. Next, by using an inverse Weierstrass transform and the Jarzynski equality, we removed the free energy associated with the force probe and determined the molecular free-energy landscape of the molecule under study, bacteriorhodopsin. The resulting landscape yielded an average unfolding free energy per amino acid (aa) of 1.0 ± 0.1 kcal/mol, in agreement with past single-molecule studies. Moreover, on a smaller spatial scale, this high-resolution landscape also agreed with an equilibrium measurement of a particular three-aa transition in bacteriorhodopsin that yielded 2.7 kcal/mol/aa, an unexpectedly high value. Hence, while average unfolding ΔG0 per aa is a useful metric, the derived high-resolution landscape details significant local variation from the mean. More generally, we demonstrated that, as anticipated, the inverse Weierstrass transform is an efficient means to reconstruct free-energy landscapes from AFM data.

  11. Landscape Design and Nursery Operation for Energy Conservation.

    Science.gov (United States)

    Bell, Richard C.; Glazener, Dennis

    Landforms, vegetation, water bodies, climate and solar radiation can be analyzed and used to design an energy-conserving landscape and horticulture operation. Accordingly, this course instructor's manual covers the use of the elements of the environment to make landscaping and nursery design and operation more energy-efficient. Five sections…

  12. Mitigation/Adaptation: landscape architecture meets sustainable energy transition

    NARCIS (Netherlands)

    Stremke, S.

    2009-01-01

    Mitigation of climate change and adaptation to renewable energy sources are among the emerging fields of activity in landscape architecture. If landscape architects recognize the need for sustainable development on the basis of renewable energy sources, then how can we contribute to sustainable and

  13. Renewable energies and European landscapes lessons from Southern European cases

    CERN Document Server

    Frolova, Marina; Nadaï, Alain

    2015-01-01

    This book provides timely, multidisciplinary cross-national comparison of the institutional and social processes through which renewable energy landscapes have emerged in Southern Europe. On the basis of case studies in these countries, it analyzes the way in which and the extent to which the development of renewable energies has affected landscape forms and whether or not it has contributed to a reformulation of landscape practices and values in these countries. Landscape is conceived broadly, as a material, social, political and historical process embedded into the local realm, going beyond

  14. New interaction paths in the energy landscape: the role of local energy initiatives

    NARCIS (Netherlands)

    de Boer, Jessica; Zuidema, Christian; Gugerell, Katharina

    2018-01-01

    Energy transition is an encompassing process which not only involves the energy system but also the landscape in which the energy system is embedded. Renewable energy is triggering new interactions with local landscapes in physical, socio-economic and institutional senses. We capture these

  15. Random versus Deterministic Descent in RNA Energy Landscape Analysis

    Directory of Open Access Journals (Sweden)

    Luke Day

    2016-01-01

    Full Text Available Identifying sets of metastable conformations is a major research topic in RNA energy landscape analysis, and recently several methods have been proposed for finding local minima in landscapes spawned by RNA secondary structures. An important and time-critical component of such methods is steepest, or gradient, descent in attraction basins of local minima. We analyse the speed-up achievable by randomised descent in attraction basins in the context of large sample sets where the size has an order of magnitude in the region of ~106. While the gain for each individual sample might be marginal, the overall run-time improvement can be significant. Moreover, for the two nongradient methods we analysed for partial energy landscapes induced by ten different RNA sequences, we obtained that the number of observed local minima is on average larger by 7.3% and 3.5%, respectively. The run-time improvement is approximately 16.6% and 6.8% on average over the ten partial energy landscapes. For the large sample size we selected for descent procedures, the coverage of local minima is very high up to energy values of the region where the samples were randomly selected from the partial energy landscapes; that is, the difference to the total set of local minima is mainly due to the upper area of the energy landscapes.

  16. The effects of landscaping on the residential cooling energy

    Science.gov (United States)

    Misni, A.

    2018-02-01

    This paper examines the effectiveness of landscaping on the air-conditioning energy saving of houses in a tropical environment. This case study involved looking at the construction and landscaping of three single-family houses in three sections of Shah Alam, Selangor, Malaysia. The houses ranged in age from 5 to 30 years old, which provided different examples of construction and maturity levels of the surrounding landscaping. Landscaping affects the thermal performance as well as on the air-conditioning energy of houses, in how it provides shade, channels wind, and evapotranspiration. While the construction of the three houses was similar, they were different in size and design, including their landscape design. These houses were chosen because they are representative of single-family tropical houses and landscaping styles in Malaysia since 30 years ago. Three houses were chosen; the 30-year-old house, the 10-year-old house, and the 5-year-old house. In a tropical country, landscaping is used to reduce the effects of the hot and humid climate. The houses spent 15-45% of the electricity cost on cooling. These results were influenced by human factors and the surrounding landscaping. Every type of vegetation, such as trees, grass, shrubs, groundcover, and turf, contributes to reducing air temperatures near the house and providing evaporative cooling.

  17. Potential energy landscape of TIP4P/2005 water

    Science.gov (United States)

    Handle, Philip H.; Sciortino, Francesco

    2018-04-01

    We report a numerical study of the statistical properties of the potential energy landscape of TIP4P/2005, one of the most accurate rigid water models. We show that, in the region where equilibrated configurations can be generated, a Gaussian landscape description is able to properly describe the model properties. We also find that the volume dependence of the landscape properties is consistent with the existence of a locus of density maxima in the phase diagram. The landscape-based equation of state accurately reproduces the TIP4P/2005 pressure-vs-volume curves, providing a sound extrapolation of the free-energy at low T. A positive-pressure liquid-liquid critical point is predicted by the resulting free-energy.

  18. Potential energy landscape of TIP4P/2005 water.

    Science.gov (United States)

    Handle, Philip H; Sciortino, Francesco

    2018-04-07

    We report a numerical study of the statistical properties of the potential energy landscape of TIP4P/2005, one of the most accurate rigid water models. We show that, in the region where equilibrated configurations can be generated, a Gaussian landscape description is able to properly describe the model properties. We also find that the volume dependence of the landscape properties is consistent with the existence of a locus of density maxima in the phase diagram. The landscape-based equation of state accurately reproduces the TIP4P/2005 pressure-vs-volume curves, providing a sound extrapolation of the free-energy at low T. A positive-pressure liquid-liquid critical point is predicted by the resulting free-energy.

  19. Chemical Denaturants Smoothen Ruggedness on the Free Energy Landscape of Protein Folding.

    Science.gov (United States)

    Malhotra, Pooja; Jethva, Prashant N; Udgaonkar, Jayant B

    2017-08-08

    To characterize experimentally the ruggedness of the free energy landscape of protein folding is challenging, because the distributed small free energy barriers are usually dominated by one, or a few, large activation free energy barriers. This study delineates changes in the roughness of the free energy landscape by making use of the observation that a decrease in ruggedness is accompanied invariably by an increase in folding cooperativity. Hydrogen exchange (HX) coupled to mass spectrometry was used to detect transient sampling of local energy minima and the global unfolded state on the free energy landscape of the small protein single-chain monellin. Under native conditions, local noncooperative openings result in interconversions between Boltzmann-distributed intermediate states, populated on an extremely rugged "uphill" energy landscape. The cooperativity of these interconversions was increased by selectively destabilizing the native state via mutations, and further by the addition of a chemical denaturant. The perturbation of stability alone resulted in seven backbone amide sites exchanging cooperatively. The size of the cooperatively exchanging and/or unfolding unit did not depend on the extent of protein destabilization. Only upon the addition of a denaturant to a destabilized mutant variant did seven additional backbone amide sites exchange cooperatively. Segmentwise analysis of the HX kinetics of the mutant variants further confirmed that the observed increase in cooperativity was due to the smoothing of the ruggedness of the free energy landscape of folding of the protein by the chemical denaturant.

  20. Inflation in random landscapes with two energy scales

    Science.gov (United States)

    Blanco-Pillado, Jose J.; Vilenkin, Alexander; Yamada, Masaki

    2018-02-01

    We investigate inflation in a multi-dimensional landscape with a hierarchy of energy scales, motivated by the string theory, where the energy scale of Kahler moduli is usually assumed to be much lower than that of complex structure moduli and dilaton field. We argue that in such a landscape, the dynamics of slow-roll inflation is governed by the low-energy potential, while the initial condition for inflation are determined by tunneling through high-energy barriers. We then use the scale factor cutoff measure to calculate the probability distribution for the number of inflationary e-folds and the amplitude of density fluctuations Q, assuming that the low-energy landscape is described by a random Gaussian potential with a correlation length much smaller than M pl. We find that the distribution for Q has a unique shape and a preferred domain, which depends on the parameters of the low-energy landscape. We discuss some observational implications of this distribution and the constraints it imposes on the landscape parameters.

  1. The German energy landscape in 2015

    International Nuclear Information System (INIS)

    Lauer, Hartmut

    2016-01-01

    This article proposes a brief overview of the German energy sector: stagnation of primary energy consumption, shares of the different energy sources (renewable, coal, lignite, oil, gas, nuclear), shares of the different electric power production sources and their recent evolution. It evokes issues related to the objectives defined for energy transition, the high level of renewable energy production and the high level of power exports. It outlines that consumption must be reduced to reach the objectives defined for 2020. It notices a stagnation of the energy system de-carbonation, and comments the evolution of electricity prices

  2. Learning free energy landscapes using artificial neural networks

    Science.gov (United States)

    Sidky, Hythem; Whitmer, Jonathan K.

    2018-03-01

    Existing adaptive bias techniques, which seek to estimate free energies and physical properties from molecular simulations, are limited by their reliance on fixed kernels or basis sets which hinder their ability to efficiently conform to varied free energy landscapes. Further, user-specified parameters are in general non-intuitive yet significantly affect the convergence rate and accuracy of the free energy estimate. Here we propose a novel method, wherein artificial neural networks (ANNs) are used to develop an adaptive biasing potential which learns free energy landscapes. We demonstrate that this method is capable of rapidly adapting to complex free energy landscapes and is not prone to boundary or oscillation problems. The method is made robust to hyperparameters and overfitting through Bayesian regularization which penalizes network weights and auto-regulates the number of effective parameters in the network. ANN sampling represents a promising innovative approach which can resolve complex free energy landscapes in less time than conventional approaches while requiring minimal user input.

  3. Learning free energy landscapes using artificial neural networks.

    Science.gov (United States)

    Sidky, Hythem; Whitmer, Jonathan K

    2018-03-14

    Existing adaptive bias techniques, which seek to estimate free energies and physical properties from molecular simulations, are limited by their reliance on fixed kernels or basis sets which hinder their ability to efficiently conform to varied free energy landscapes. Further, user-specified parameters are in general non-intuitive yet significantly affect the convergence rate and accuracy of the free energy estimate. Here we propose a novel method, wherein artificial neural networks (ANNs) are used to develop an adaptive biasing potential which learns free energy landscapes. We demonstrate that this method is capable of rapidly adapting to complex free energy landscapes and is not prone to boundary or oscillation problems. The method is made robust to hyperparameters and overfitting through Bayesian regularization which penalizes network weights and auto-regulates the number of effective parameters in the network. ANN sampling represents a promising innovative approach which can resolve complex free energy landscapes in less time than conventional approaches while requiring minimal user input.

  4. Distributed Renewable Energy Generation and Landscape Architecture: A Critical Review

    OpenAIRE

    Beck, Osmer DeVon

    2010-01-01

    Governments and utility organizations around the world have mandated and provided incentives for new distributed renewable energy generation (DREG) capacity, and market projections indicate strong growth in distributed renewable energy generation installations in the coming years. New distributed renewable energy generation utilities, by definition, will be primarily located in built environments near consumers; these utilities are often planned and designed by landscape architects, yet no ev...

  5. Sustainable energy landscapes: The power of imagination

    NARCIS (Netherlands)

    Stremke, S.

    2012-01-01

    Resource depletion and climate change motivate a transition to sustainable energy systems that make effective use of renewable sources. Sustainable energy transition necessitates a transformation of large parts of the existing built environment and presents one of the great challenges of present-day

  6. Energy landscapes for mobile ions in ion conducting solids

    Indian Academy of Sciences (India)

    demonstrated here for a range of metaphosphate and diborate glasses, the complete description of the energy landscape for mobile ions also provides an effective tool for achieving a more detailed understanding of ion transport in glasses. The investigation of time evolutions can be included, if the bond valence analysis is ...

  7. Membranes: A Variety of Energy Landscapes for Many Transfer Opportunities

    Science.gov (United States)

    2018-01-01

    A membrane can be represented by an energy landscape that solutes or colloids must cross. A model accounting for the momentum and the mass balances in the membrane energy landscape establishes a new way of writing for the Darcy law. The counter-pressure in the Darcy law is no longer written as the result of an osmotic pressure difference but rather as a function of colloid-membrane interactions. The ability of the model to describe the physics of the filtration is discussed in detail. This model is solved in a simplified energy landscape to derive analytical relationships that describe the selectivity and the counter-pressure from ab initio operating conditions. The model shows that the stiffness of the energy landscape has an impact on the process efficiency: a gradual increase in interactions (such as with hourglass pore shape) can reduce the separation energetic cost. It allows the introduction of a new paradigm to increase membrane efficiency: the accumulation that is inherent to the separation must be distributed across the membrane. Asymmetric interactions thus lead to direction-dependent transfer properties and the membrane exhibits diode behavior. These new transfer opportunities are discussed. PMID:29470440

  8. Quantifying the topography of the intrinsic energy landscape of flexible biomolecular recognition

    Science.gov (United States)

    Chu, Xiakun; Gan, Linfeng; Wang, Erkang; Wang, Jin

    2013-01-01

    Biomolecular functions are determined by their interactions with other molecules. Biomolecular recognition is often flexible and associated with large conformational changes involving both binding and folding. However, the global and physical understanding for the process is still challenging. Here, we quantified the intrinsic energy landscapes of flexible biomolecular recognition in terms of binding–folding dynamics for 15 homodimers by exploring the underlying density of states, using a structure-based model both with and without considering energetic roughness. By quantifying three individual effective intrinsic energy landscapes (one for interfacial binding, two for monomeric folding), the association mechanisms for flexible recognition of 15 homodimers can be classified into two-state cooperative “coupled binding–folding” and three-state noncooperative “folding prior to binding” scenarios. We found that the association mechanism of flexible biomolecular recognition relies on the interplay between the underlying effective intrinsic binding and folding energy landscapes. By quantifying the whole global intrinsic binding–folding energy landscapes, we found strong correlations between the landscape topography measure Λ (dimensionless ratio of energy gap versus roughness modulated by the configurational entropy) and the ratio of the thermodynamic stable temperature versus trapping temperature, as well as between Λ and binding kinetics. Therefore, the global energy landscape topography determines the binding–folding thermodynamics and kinetics, crucial for the feasibility and efficiency of realizing biomolecular function. We also found “U-shape” temperature-dependent kinetic behavior and a dynamical cross-over temperature for dividing exponential and nonexponential kinetics for two-state homodimers. Our study provides a unique way to bridge the gap between theory and experiments. PMID:23754431

  9. Evaluating the landscape impact of renewable energy plants

    Science.gov (United States)

    Ioannidis, Romanos; Koutsoyiannis, Demetris

    2017-04-01

    Different types of renewable energy have been on an ongoing competition with each other. There has been a lot of research comparing the most common types of renewable energy plants in relation with their efficiency, cost and environmental impact. However, few papers so far have attempted to analyse their impact on landscape and there has never been in depth research on which type of renewable energy causes the least impact on the natural, cultural and aesthetic characteristics of a landscape. This seems to be a significant omission given the vast areas of land already covered with renewable energy plants and the worldwide plans for many more renewable energy projects in the future. Meanwhile, the low aesthetic quality of renewable energy plants has already been an obstacle to their further development, with several relevant examples from countries such as Spain and the Netherlands. There have even been cases where aesthetic degradation is the primary or even the single argument of the opposition to proposed plants. In any case, the aesthetic design and the integration of renewable energy plants into the landscape should really be important design parameters if we plan those projects to truly be sustainable and to be considered complete works of engineering. To initiate dialogue over those aspects of renewable energy, we provide a first comparison on hydro, solar and wind energy. To materialize this comparison, we use data from existing dams, photovoltaic and wind farms. Initially, the average area per MW covered by each type of energy plant is calculated and then evaluated qualitatively from a landscape-impact perspective. Although the area affected is comparable in these three cases, the analysis of the data suggests that dams offer a considerable amount of advantages compared to the other two types of plants. This conclusion arises from the fact that dams, whose basic impact to the landscape is the creation of an artificial lake, contribute much less to the

  10. Physics landscape-fixed target energies

    Energy Technology Data Exchange (ETDEWEB)

    Berger, E.L.

    1989-10-01

    An introductory review is presented of physics issues and opportunities at Fermilab fixed-target energies. Included are discussions of precision electroweak studies; deep inelastic lepton scattering; heavy quark production, spectroscopy, and decays; perturbative QCD; prompt photon production; massive lepton production; and spin dependence. 79 refs., 7 figs.

  11. Orientational dynamics and energy landscape features of ...

    Indian Academy of Sciences (India)

    WINTEC

    separation between the two ellipsoids of revolution in a side-by-side configuration, rij is the distance bet- ween the centers of mass of the ellipsoids of revolu- tion i and j, and ˆ. / ij ij ij. r r r. = is a unit vector along the intermolecular separation vector rij. The molecular shape parameter σ and the energy parameter ε both.

  12. Physics landscape-fixed target energies

    International Nuclear Information System (INIS)

    Berger, E.L.

    1989-10-01

    An introductory review is presented of physics issues and opportunities at Fermilab fixed-target energies. Included are discussions of precision electroweak studies; deep inelastic lepton scattering; heavy quark production, spectroscopy, and decays; perturbative QCD; prompt photon production; massive lepton production; and spin dependence. 79 refs., 7 figs

  13. Energy landscapes of resting-state brain networks

    Directory of Open Access Journals (Sweden)

    Takamitsu eWatanabe

    2014-02-01

    Full Text Available During rest, the human brain performs essential functions such as memory maintenance, which are associated with resting-state brain networks (RSNs including the default-mode network (DMN and frontoparietal network (FPN. Previous studies based on spiking-neuron network models and their reduced models, as well as those based on imaging data, suggest that resting-state network activity can be captured as attractor dynamics, i.e., dynamics of the brain state toward an attractive state and transitions between different attractors. Here, we analyze the energy landscapes of the RSNs by applying the maximum entropy model, or equivalently the Ising spin model, to human RSN data. We use the previously estimated parameter values to define the energy landscape, and the disconnectivity graph method to estimate the number of local energy minima (equivalent to attractors in attractor dynamics, the basin size, and hierarchical relationships among the different local minima. In both of the DMN and FPN, low-energy local minima tended to have large basins. A majority of the network states belonged to a basin of one of a few local minima. Therefore, a small number of local minima constituted the backbone of each RSN. In the DMN, the energy landscape consisted of two groups of low-energy local minima that are separated by a relatively high energy barrier. Within each group, the activity patterns of the local minima were similar, and different minima were connected by relatively low energy barriers. In the FPN, all dominant energy were separated by relatively low energy barriers such that they formed a single coarse-grained global minimum. Our results indicate that multistable attractor dynamics may underlie the DMN, but not the FPN, and assist memory maintenance with different memory states.

  14. On the potential energy landscape of supercooled liquids and glasses

    DEFF Research Database (Denmark)

    Rodney, D.; Schrøder, Thomas

    2011-01-01

    The activation-relaxation technique (ART), a saddle-point search method, is applied to determine the potential energy landscape around supercooled and glassy configurations of a three-dimensional binary Lennard-Jones system. We show a strong relation between the distribution of activation energies...... of transitions undergone by the same supercooled liquid during a time trajectory simulated by molecular dynamics. We find that ART is biased towards more heterogeneous transitions with higher activation energies and more broken bonds than the MD simulation....

  15. Dynamic force spectroscopy of DNA hairpins: I. Force kinetics and free energy landscapes

    International Nuclear Information System (INIS)

    Mossa, A; Manosas, M; Forns, N; Huguet, J M; Ritort, F

    2009-01-01

    We investigate the thermodynamics and kinetics of DNA hairpins that fold/unfold under the action of applied mechanical force. We introduce the concept of the molecular free energy landscape and derive simplified expressions for the force dependent Kramers–Bell rates. To test the theory we have designed a specific DNA hairpin sequence that shows two-state cooperative folding under mechanical tension and carried out pulling experiments using optical tweezers. We show how we can determine the parameters that characterize the molecular free energy landscape of such sequences from rupture force kinetic studies. Finally we combine such kinetic studies with experimental investigations of the Crooks fluctuation relation to derive the free energy of formation of the hairpin at zero force

  16. Energy landscape of 3D spin Hamiltonians with topological order.

    Science.gov (United States)

    Bravyi, Sergey; Haah, Jeongwan

    2011-10-07

    We explore the feasibility of a quantum self-correcting memory based on 3D spin Hamiltonians with topological quantum order in which thermal diffusion of topological defects is suppressed by macroscopic energy barriers. To this end we characterize the energy landscape of stabilizer code Hamiltonians with local bounded-strength interactions which have a topologically ordered ground state but do not have stringlike logical operators. We prove that any sequence of local errors mapping a ground state of such a Hamiltonian to an orthogonal ground state must cross an energy barrier growing at least as a logarithm of the lattice size. Our bound on the energy barrier is tight up to a constant factor for one particular 3D spin Hamiltonian.

  17. Characterizing structural transitions using localized free energy landscape analysis.

    Directory of Open Access Journals (Sweden)

    Nilesh K Banavali

    Full Text Available Structural changes in molecules are frequently observed during biological processes like replication, transcription and translation. These structural changes can usually be traced to specific distortions in the backbones of the macromolecules involved. Quantitative energetic characterization of such distortions can greatly advance the atomic-level understanding of the dynamic character of these biological processes.Molecular dynamics simulations combined with a variation of the Weighted Histogram Analysis Method for potential of mean force determination are applied to characterize localized structural changes for the test case of cytosine (underlined base flipping in a GTCAGCGCATGG DNA duplex. Free energy landscapes for backbone torsion and sugar pucker degrees of freedom in the DNA are used to understand their behavior in response to the base flipping perturbation. By simplifying the base flipping structural change into a two-state model, a free energy difference of upto 14 kcal/mol can be attributed to the flipped state relative to the stacked Watson-Crick base paired state. This two-state classification allows precise evaluation of the effect of base flipping on local backbone degrees of freedom.The calculated free energy landscapes of individual backbone and sugar degrees of freedom expectedly show the greatest change in the vicinity of the flipping base itself, but specific delocalized effects can be discerned upto four nucleotide positions away in both 5' and 3' directions. Free energy landscape analysis thus provides a quantitative method to pinpoint the determinants of structural change on the atomic scale and also delineate the extent of propagation of the perturbation along the molecule. In addition to nucleic acids, this methodology is anticipated to be useful for studying conformational changes in all macromolecules, including carbohydrates, lipids, and proteins.

  18. Sustainable Energy Landscape: Implementing Energy Transition in the Physical Realm

    NARCIS (Netherlands)

    Stremke, S.

    2015-01-01

    Since the beginning of the new millennium, the concept of “energy landscape” is being discussed by academia from the environmental design domain while more and more practitioners have been contributing to sustainable energy transition. Yet, there remains some ambiguity as to what exactly is meant

  19. New Energy Landscapes of Pennsylvania: Forests to Farms to Fracking

    Science.gov (United States)

    Johnson, Deborah A.

    This dissertation adds to the literature on energy needed by industry, government, and citizens for decision-making. The pursuit to access or create new energy resources spawns new landscapes of energy in the early 21st century. The combination of hydraulic fracturing and horizontal drilling technologies---popularly called "fracking"---enables entry into previously inaccessible natural gas reserves such as the Marcellus shale much of which lies beneath Pennsylvania. Although this unconventional method offers a promising source of domestic energy and job growth, the potential for negative impacts raises concerns and questions. The questions include: What is the controversy about fracking in Pennsylvania? What are the impacts of fracking? What costs is Pennsylvania paying as it shifts to shale gas extraction? Are there activities taking place or material signs that point to the emerging new landscapes? Are the individuals and organizations that resist shale gas extraction---the so-called "Green Forces"---and others who live within the region of development more or less attuned to these costs? A mixed methods approach consists of landscape and stakeholder analyses including visual examination of GIS-generated maps, satellite images, and photos taken in the field specifically from four counties: Washington, Warren, McKean, and Bradford. Research captures stakeholders' voices across the public, government, and private sectors at different scales. A stakeholder matrix facilitates data organization and analysis. Data include 114 individual statements from an EPA Public Meeting, texts from 40 online-newspaper articles or blogs, and face-to-face interviews or focus group participation of 36 individuals. Further data come from a public health conference, industry convention, and public protest. The new energy landscape covers spaces in Pennsylvania where oil and gas development previously had not been present. It obscures as well as exposes the legacy of past energy

  20. Spatial resilience of forested landscapes under climate change and management

    Science.gov (United States)

    Melissa S. Lucash; Robert M. Scheller; Eric J. Gustafson; Brian R. Sturtevant

    2017-01-01

    Context Resilience, the ability to recover from disturbance, has risen to the forefront of scientific policy, but is difficult to quantify, particularly in large, forested landscapes subject to disturbances, management, and climate change. Objectives Our objective was to determine which spatial drivers will control landscape...

  1. The mechanisms for filling carbon nanotubes with molten salts: carbon nanotubes as energy landscape filters

    International Nuclear Information System (INIS)

    Bishop, Clare L; Wilson, Mark

    2009-01-01

    The mechanisms for filling carbon nanotubes with molten salts are investigated using molecular dynamics computer simulation. Inorganic nanotubular structures, whose morphologies can be rationalized in terms of the folding, or the removal of sections from, planes of square nets are found to form. The formation mechanisms are found to follow a 'chain-by-chain' motif in which the structures build systematically from charge neutral M-X-M-Xc chains. The formation mechanisms are rationalized in terms of the ion-ion interactions (intra-chain and inter-chain terms). In addition, the mechanisms of filling are discussed in terms of a 'hopping' between basins on the underlying energy landscape. The role of the carbon nanotube as an energy landscape filter is discussed.

  2. A data-driven analysis of energy balance closure across FLUXNET research sites: The role of landscape scale heterogeneity

    DEFF Research Database (Denmark)

    Stoy, Paul C.; Mauder, Matthias; Foken, Thomas

    2013-01-01

    The energy balance at most surface-atmosphere flux research sites remains unclosed. The mechanisms underlying the discrepancy between measured energy inputs and outputs across the global FLUXNET tower network are still under debate. Recent reviews have identified exchange processes and turbulent...... motions at large spatial and temporal scales in heterogeneous landscapes as the primary cause of the lack of energy balance closure at some intensively-researched sites, while unmeasured storage terms cannot be ruled out as a dominant contributor to the lack of energy balance closure at many other sites....... We analyzed energy balance closure across 173 ecosystems in the FLUXNET database and explored the relationship between energy balance closure and landscape heterogeneity using MODIS products and GLOBEstat elevation data. Energy balance closure per research site (CEB,s) averaged 0.84±0.20, with best...

  3. Multiscale coarse-graining of the protein energy landscape.

    Directory of Open Access Journals (Sweden)

    Ronald D Hills

    2010-06-01

    Full Text Available A variety of coarse-grained (CG models exists for simulation of proteins. An outstanding problem is the construction of a CG model with physically accurate conformational energetics rivaling all-atom force fields. In the present work, atomistic simulations of peptide folding and aggregation equilibria are force-matched using multiscale coarse-graining to develop and test a CG interaction potential of general utility for the simulation of proteins of arbitrary sequence. The reduced representation relies on multiple interaction sites to maintain the anisotropic packing and polarity of individual sidechains. CG energy landscapes computed from replica exchange simulations of the folding of Trpzip, Trp-cage and adenylate kinase resemble those of other reduced representations; non-native structures are observed with energies similar to those of the native state. The artifactual stabilization of misfolded states implies that non-native interactions play a deciding role in deviations from ideal funnel-like cooperative folding. The role of surface tension, backbone hydrogen bonding and the smooth pairwise CG landscape is discussed. Ab initio folding aside, the improved treatment of sidechain rotamers results in stability of the native state in constant temperature simulations of Trpzip, Trp-cage, and the open to closed conformational transition of adenylate kinase, illustrating the potential value of the CG force field for simulating protein complexes and transitions between well-defined structural states.

  4. Optimization of landscape services under uncoordinated management by multiple landowners.

    Science.gov (United States)

    Porto, Miguel; Correia, Otília; Beja, Pedro

    2014-01-01

    Landscapes are often patchworks of private properties, where composition and configuration patterns result from cumulative effects of the actions of multiple landowners. Securing the delivery of services in such multi-ownership landscapes is challenging, because it is difficult to assure tight compliance to spatially explicit management rules at the level of individual properties, which may hinder the conservation of critical landscape features. To deal with these constraints, a multi-objective simulation-optimization procedure was developed to select non-spatial management regimes that best meet landscape-level objectives, while accounting for uncoordinated and uncertain response of individual landowners to management rules. Optimization approximates the non-dominated Pareto frontier, combining a multi-objective genetic algorithm and a simulator that forecasts trends in landscape pattern as a function of management rules implemented annually by individual landowners. The procedure was demonstrated with a case study for the optimum scheduling of fuel treatments in cork oak forest landscapes, involving six objectives related to reducing management costs (1), reducing fire risk (3), and protecting biodiversity associated with mid- and late-successional understories (2). There was a trade-off between cost, fire risk and biodiversity objectives, that could be minimized by selecting management regimes involving ca. 60% of landowners clearing the understory at short intervals (around 5 years), and the remaining managing at long intervals (ca. 75 years) or not managing. The optimal management regimes produces a mosaic landscape dominated by stands with herbaceous and low shrub understories, but also with a satisfactory representation of old understories, that was favorable in terms of both fire risk and biodiversity. The simulation-optimization procedure presented can be extended to incorporate a wide range of landscape dynamic processes, management rules and quantifiable

  5. Optimization of landscape services under uncoordinated management by multiple landowners.

    Directory of Open Access Journals (Sweden)

    Miguel Porto

    Full Text Available Landscapes are often patchworks of private properties, where composition and configuration patterns result from cumulative effects of the actions of multiple landowners. Securing the delivery of services in such multi-ownership landscapes is challenging, because it is difficult to assure tight compliance to spatially explicit management rules at the level of individual properties, which may hinder the conservation of critical landscape features. To deal with these constraints, a multi-objective simulation-optimization procedure was developed to select non-spatial management regimes that best meet landscape-level objectives, while accounting for uncoordinated and uncertain response of individual landowners to management rules. Optimization approximates the non-dominated Pareto frontier, combining a multi-objective genetic algorithm and a simulator that forecasts trends in landscape pattern as a function of management rules implemented annually by individual landowners. The procedure was demonstrated with a case study for the optimum scheduling of fuel treatments in cork oak forest landscapes, involving six objectives related to reducing management costs (1, reducing fire risk (3, and protecting biodiversity associated with mid- and late-successional understories (2. There was a trade-off between cost, fire risk and biodiversity objectives, that could be minimized by selecting management regimes involving ca. 60% of landowners clearing the understory at short intervals (around 5 years, and the remaining managing at long intervals (ca. 75 years or not managing. The optimal management regimes produces a mosaic landscape dominated by stands with herbaceous and low shrub understories, but also with a satisfactory representation of old understories, that was favorable in terms of both fire risk and biodiversity. The simulation-optimization procedure presented can be extended to incorporate a wide range of landscape dynamic processes, management rules

  6. Hierarchical Protein Free Energy Landscapes from Variationally Enhanced Sampling.

    Science.gov (United States)

    Shaffer, Patrick; Valsson, Omar; Parrinello, Michele

    2016-12-13

    In recent work, we demonstrated that it is possible to obtain approximate representations of high-dimensional free energy surfaces with variationally enhanced sampling ( Shaffer, P.; Valsson, O.; Parrinello, M. Proc. Natl. Acad. Sci. , 2016 , 113 , 17 ). The high-dimensional spaces considered in that work were the set of backbone dihedral angles of a small peptide, Chignolin, and the high-dimensional free energy surface was approximated as the sum of many two-dimensional terms plus an additional term which represents an initial estimate. In this paper, we build on that work and demonstrate that we can calculate high-dimensional free energy surfaces of very high accuracy by incorporating additional terms. The additional terms apply to a set of collective variables which are more coarse than the base set of collective variables. In this way, it is possible to build hierarchical free energy surfaces, which are composed of terms that act on different length scales. We test the accuracy of these free energy landscapes for the proteins Chignolin and Trp-cage by constructing simple coarse-grained models and comparing results from the coarse-grained model to results from atomistic simulations. The approach described in this paper is ideally suited for problems in which the free energy surface has important features on different length scales or in which there is some natural hierarchy.

  7. Landscape of Future Accelerators at the Energy and Intensity Frontier

    Energy Technology Data Exchange (ETDEWEB)

    Syphers, M. J. [Northern Illinois U.; Chattopadhyay, S. [Northern Illinois U.

    2016-11-21

    An overview is provided of the currently envisaged landscape of charged particle accelerators at the energy and intensity frontiers to explore particle physics beyond the standard model via 1-100 TeV-scale lepton and hadron colliders and multi-Megawatt proton accelerators for short- and long- baseline neutrino experiments. The particle beam physics, associated technological challenges and progress to date for these accelerator facilities (LHC, HL-LHC, future 100 TeV p-p colliders, Tev-scale linear and circular electron-positron colliders, high intensity proton accelerator complex PIP-II for DUNE and future upgrade to PIP-III) are outlined. Potential and prospects for advanced “nonlinear dynamic techniques” at the multi-MW level intensity frontier and advanced “plasma- wakefield-based techniques” at the TeV-scale energy frontier and are also described.

  8. Multivariable extrapolation of grand canonical free energy landscapes

    Science.gov (United States)

    Mahynski, Nathan A.; Errington, Jeffrey R.; Shen, Vincent K.

    2017-12-01

    We derive an approach for extrapolating the free energy landscape of multicomponent systems in the grand canonical ensemble, obtained from flat-histogram Monte Carlo simulations, from one set of temperature and chemical potentials to another. This is accomplished by expanding the landscape in a Taylor series at each value of the order parameter which defines its macrostate phase space. The coefficients in each Taylor polynomial are known exactly from fluctuation formulas, which may be computed by measuring the appropriate moments of extensive variables that fluctuate in this ensemble. Here we derive the expressions necessary to define these coefficients up to arbitrary order. In principle, this enables a single flat-histogram simulation to provide complete thermodynamic information over a broad range of temperatures and chemical potentials. Using this, we also show how to combine a small number of simulations, each performed at different conditions, in a thermodynamically consistent fashion to accurately compute properties at arbitrary temperatures and chemical potentials. This method may significantly increase the computational efficiency of biased grand canonical Monte Carlo simulations, especially for multicomponent mixtures. Although approximate, this approach is amenable to high-throughput and data-intensive investigations where it is preferable to have a large quantity of reasonably accurate simulation data, rather than a smaller amount with a higher accuracy.

  9. Pest-suppression potential of midwestern landscapes under contrasting bioenergy scenarios.

    Science.gov (United States)

    Meehan, Timothy D; Werling, Ben P; Landis, Douglas A; Gratton, Claudio

    2012-01-01

    Biomass crops grown on marginal soils are expected to fuel an emerging bioenergy industry in the United States. Bioenergy crop choice and position in the landscape could have important impacts on a range of ecosystem services, including natural pest-suppression (biocontrol services) provided by predatory arthropods. In this study we use predation rates of three sentinel crop pests to develop a biocontrol index (BCI) summarizing pest-suppression potential in corn and perennial grass-based bioenergy crops in southern Wisconsin, lower Michigan, and northern Illinois. We show that BCI is higher in perennial grasslands than in corn, and increases with the amount of perennial grassland in the surrounding landscape. We develop an empirical model for predicting BCI from information on energy crop and landscape characteristics, and use the model in a qualitative assessment of changes in biocontrol services for annual croplands on prime agricultural soils under two contrasting bioenergy scenarios. Our analysis suggests that the expansion of annual energy crops onto 1.2 million ha of existing perennial grasslands on marginal soils could reduce BCI between -10 and -64% for nearly half of the annual cropland in the region. In contrast, replacement of the 1.1 million ha of existing annual crops on marginal land with perennial energy crops could increase BCI by 13 to 205% on over half of the annual cropland in the region. Through comparisons with other independent studies, we find that our biocontrol index is negatively related to insecticide use across the Midwest, suggesting that strategically positioned, perennial bioenergy crops could reduce insect damage and insecticide use on neighboring food and forage crops. We suggest that properly validated environmental indices can be used in decision support systems to facilitate integrated assessments of the environmental and economic impacts of different bioenergy policies.

  10. Approximate scaling properties of RNA free energy landscapes

    Science.gov (United States)

    Baskaran, S.; Stadler, P. F.; Schuster, P.

    1996-01-01

    RNA free energy landscapes are analysed by means of "time-series" that are obtained from random walks restricted to excursion sets. The power spectra, the scaling of the jump size distribution, and the scaling of the curve length measured with different yard stick lengths are used to describe the structure of these "time series". Although they are stationary by construction, we find that their local behavior is consistent with both AR(1) and self-affine processes. Random walks confined to excursion sets (i.e., with the restriction that the fitness value exceeds a certain threshold at each step) exhibit essentially the same statistics as free random walks. We find that an AR(1) time series is in general approximately self-affine on timescales up to approximately the correlation length. We present an empirical relation between the correlation parameter rho of the AR(1) model and the exponents characterizing self-affinity.

  11. A Data-Driven Evolutionary Algorithm for Mapping Multibasin Protein Energy Landscapes.

    Science.gov (United States)

    Clausen, Rudy; Shehu, Amarda

    2015-09-01

    Evidence is emerging that many proteins involved in proteinopathies are dynamic molecules switching between stable and semistable structures to modulate their function. A detailed understanding of the relationship between structure and function in such molecules demands a comprehensive characterization of their conformation space. Currently, only stochastic optimization methods are capable of exploring conformation spaces to obtain sample-based representations of associated energy surfaces. These methods have to address the fundamental but challenging issue of balancing computational resources between exploration (obtaining a broad view of the space) and exploitation (going deep in the energy surface). We propose a novel algorithm that strikes an effective balance by employing concepts from evolutionary computation. The algorithm leverages deposited crystal structures of wildtype and variant sequences of a protein to define a reduced, low-dimensional search space from where to rapidly draw samples. A multiscale technique maps samples to local minima of the all-atom energy surface of a protein under investigation. Several novel algorithmic strategies are employed to avoid premature convergence to particular minima and obtain a broad view of a possibly multibasin energy surface. Analysis of applications on different proteins demonstrates the broad utility of the algorithm to map multibasin energy landscapes and advance modeling of multibasin proteins. In particular, applications on wildtype and variant sequences of proteins involved in proteinopathies demonstrate that the algorithm makes an important first step toward understanding the impact of sequence mutations on misfunction by providing the energy landscape as the intermediate explanatory link between protein sequence and function.

  12. Mapping the Topography of a Protein Energy Landscape.

    Science.gov (United States)

    Hutton, Richard D; Wilkinson, James; Faccin, Mauro; Sivertsson, Elin M; Pelizzola, Alessandro; Lowe, Alan R; Bruscolini, Pierpaolo; Itzhaki, Laura S

    2015-11-25

    Protein energy landscapes are highly complex, yet the vast majority of states within them tend to be invisible to experimentalists. Here, using site-directed mutagenesis and exploiting the simplicity of tandem-repeat protein structures, we delineate a network of these states and the routes between them. We show that our target, gankyrin, a 226-residue 7-ankyrin-repeat protein, can access two alternative (un)folding pathways. We resolve intermediates as well as transition states, constituting a comprehensive series of snapshots that map early and late stages of the two pathways and show both to be polarized such that the repeat array progressively unravels from one end of the molecule or the other. Strikingly, we find that the protein folds via one pathway but unfolds via a different one. The origins of this behavior can be rationalized using the numerical results of a simple statistical mechanics model that allows us to visualize the equilibrium behavior as well as single-molecule folding/unfolding trajectories, thereby filling in the gaps that are not accessible to direct experimental observation. Our study highlights the complexity of repeat-protein folding arising from their symmetrical structures; at the same time, however, this structural simplicity enables us to dissect the complexity and thereby map the precise topography of the energy landscape in full breadth and remarkable detail. That we can recapitulate the key features of the folding mechanism by computational analysis of the native structure alone will help toward the ultimate goal of designed amino-acid sequences with made-to-measure folding mechanisms-the Holy Grail of protein folding.

  13. Sustaining forest landscape connectivity under different land cover change scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Rubio, L.; Rodriguez-Freire, M.; Mateo-Sanchez, M. C.; Estreguil, C.; Saura, S.

    2012-11-01

    Managing forest landscapes to sustain functional connectivity is considered one of the key strategies to counteract the negative effects of climate and human-induced changes in forest species pools. With this objective, we evaluated whether a robust network of forest connecting elements can be identified so that it remains efficient when facing different types of potential land cover changes that may affect forest habitat networks and ecological fluxes. For this purpose we considered changes both in the forested areas and in the non-forest intervening landscape matrix. We combined some of the most recent developments in graph theory with models of land cover permeability and least-cost analysis through the forest landscape. We focused on a case of study covering the habitat of a forest dwelling bird (nuthatch, Sitta europaea) in the region of Galicia (NW Spain). Seven land-use change scenarios were analysed for their effects on connecting forest elements (patches and links): one was the simplest case in which the landscape is represented as a binary forest/non-forest pattern (and where matrix heterogeneity is disregarded), four scenarios in which forest lands were converted to other cover types (to scrubland due to wildfires, to extensive and intensive agriculture, and to urban areas), and two scenarios that only involved changes in the non-forested matrix (re naturalization and intensification). Our results show that while the network of connecting elements for the species was very robust to the conversion of the forest habitat patches to different cover types, the different change scenarios in the landscape matrix could more significantly weaken its long-term validity and effectiveness. This is particularly the case when most of the key connectivity providers for the nuthatch are located outside the protected areas or public forests in Galicia, where biodiversity-friendly measures might be more easily implemented. We discuss how the methodology can be applied to

  14. Fitness landscapes among many options under social influence.

    Science.gov (United States)

    Caiado, Camila C S; Brock, William A; Bentley, R Alexander; O'Brien, Michael J

    2016-09-21

    Cultural learning represents a novel problem in that an optimal decision depends not only on intrinsic utility of the decision/behavior but also on transparency of costs and benefits, the degree of social versus individual learning, and the relative popularity of each possible choice in a population. In terms of a fitness-landscape function, this recursive relationship means that multiple equilibria can exist. Here we use discrete-choice theory to construct a fitness-landscape function for a bi-axial decision-making map that plots the magnitude of social influence in the learning process against the costs and payoffs of decisions. Specifically, we use econometric and statistical methods to estimate not only the fitness function but also movements along the map axes. To search for these equilibria, we employ a hill-climbing algorithm that leads to the expected values of optimal decisions, which we define as peaks on the fitness landscape. We illustrate how estimation of a measure of transparency, a measure of social influence, and the associated fitness landscape can be accomplished using panel data sets. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Energy landscapes shape microbial communities in hydrothermal systems on the Arctic Mid-Ocean Ridge.

    Science.gov (United States)

    Dahle, Håkon; Økland, Ingeborg; Thorseth, Ingunn H; Pederesen, Rolf B; Steen, Ida H

    2015-07-01

    Methods developed in geochemical modelling combined with recent advances in molecular microbial ecology provide new opportunities to explore how microbial communities are shaped by their chemical surroundings. Here, we present a framework for analyses of how chemical energy availability shape chemotrophic microbial communities in hydrothermal systems through an investigation of two geochemically different basalt-hosted hydrothermal systems on the Arctic Mid-Ocean Ridge: the Soria Moria Vent field (SMVF) and the Loki's Castle Vent Field (LCVF). Chemical energy landscapes were evaluated through modelling of the Gibbs energy from selected redox reactions under different mixing ratios between seawater and hydrothermal fluids. Our models indicate that the sediment-influenced LCVF has a much higher potential for both anaerobic and aerobic methane oxidation, as well as aerobic ammonium and hydrogen oxidation, than the SMVF. The modelled energy landscapes were used to develop microbial community composition models, which were compared with community compositions in environmental samples inside or on the exterior of hydrothermal chimneys, as assessed by pyrosequencing of partial 16S rRNA genes. We show that modelled microbial communities based solely on thermodynamic considerations can have a high predictive power and provide a framework for analyses of the link between energy availability and microbial community composition.

  16. Free energy landscape of a minimalist salt bridge model.

    Science.gov (United States)

    Li, Xubin; Lv, Chao; Corbett, Karen M; Zheng, Lianqing; Wu, Dongsheng; Yang, Wei

    2016-01-01

    Salt bridges are essential to protein stability and dynamics. Despite the importance, there has been scarce of detailed discussion on how salt bridge partners interact with each other in distinct solvent exposed environments. In this study, employing a recent generalized orthogonal space tempering (gOST) method, we enabled efficient molecular dynamics simulation of repetitive breaking and reforming of salt bridge structures within a minimalist salt-bridge model, the Asp-Arg dipeptide and thereby were able to map its detailed free energy landscape in aqueous solution. Free energy surface analysis shows that although individually-solvated states are more favorable, salt-bridge states still occupy a noticeable portion of the overall population. Notably, the competing forces, e.g. intercharge attractions that drive the formation of salt bridges and solvation forces that pull the charged groups away from each other, are energetically comparable. As the result, the salt bridge stability is highly tunable by local environments; for instance when local water molecules are perturbed to interact more strongly with each other, the population of the salt-bridge states is likely to increase. Our results reveal the critical role of local solvent structures in modulating salt-bridge partner interactions and imply the importance of water fluctuations on conformational dynamics that involves solvent accessible salt bridge formations. © 2015 The Protein Society.

  17. Landscape, kinetics, paths and statistics of curl flux, coherence, entanglement and energy transfer in non-equilibrium quantum systems

    International Nuclear Information System (INIS)

    Zhang, Zhedong; Wang, Jin

    2015-01-01

    We develop a population and flux landscape theory for general non-equilibrium quantum systems. We illustrate our theory by modelling the quantum transport of donor-acceptor energy transfer. We find two driving forces for the non-equilibrium quantum dynamics. The symmetric part of the driving force corresponds to the population landscape contribution which mainly governs the equilibrium part of dynamics while the anti-symmetric part of the driving force generates the non-equilibrium curl quantum flux which leads to the detailed-balance-breaking and time-irreversibility. The multi-loop structure of the flux emerges forms the flux-landscape. We study the trend of changes in population and flux-landscape with respect to the voltage (temperature difference induced by environments) and electronic coupling. Improving the voltage and electronic coupling in general facilitates the quantum transport by reducing the population landscape barriers between major states and increasing the mean value of the flux. A limit-cycle mode emerges when the underlying flux-landscape becomes funnelled with a significant gap between the largest flux loop and the rest of them. On the kinetic level, we find that multiple kinetic paths between quantum states emerge and illustrate the interference effects. The degree of interference is determined by the landscape and flux. Furthermore, we quantify kinetic rate which strongly correlates with the population landscape and flux. For quantum transport, we demonstrate that as the coherence or the quantum entanglement is enhanced, the flux and energy transfer efficiency are increased. Finally it is surprising that the non-equilibriumness quantified by voltage has a non-trivial contribution on strengthening the entanglement, which is attributed to the non-local feature of the quantum curl flux. (paper)

  18. The environmental benefits of cellulosic energy crops at a landscape scale

    International Nuclear Information System (INIS)

    Graham, R.L.; Liu, W.; English, B.C.

    1995-01-01

    The objective of this paper is to present a broad overview of the potential environmental impacts of biomass energy from energy crops--particularly the cellulosic energy crops current under development. For this discussion, the term energy crop refers to a crop grown primarily to create feedstock for either making biofuels such as ethanol or burning in a heat or electricity generation facility. Cellulosic energy crops are designed to be used in cellulose-based ethanol conversion processes (as opposed to starch or sugar-based ethanol conversion processes). As more cellulose can be produced per hectare of land than can sugar or starch, the cellulose-based ethanol conversion process is a more efficient sue of land for ethanol production. Assessing the environmental impacts of biomass energy from energy crops is complex because the environmental impact of using biomass for energy must be considered in the context of alternative energy options while the environmental impact of producing biomass from energy crops must be considered in the context of alternative land-uses. Using biomass-derived energy can reduce greenhouse gas emissions or increase them; growing biomass energy crops can enhance soil fertility or degrade it. Without knowing the context of the biomass energy, one can say little about its specific environmental impacts. The primary focus of this paper is an evaluation of the environmental impacts of growing cellulosic energy crops especially at the landscape or regional scale. However, to set the stage for this discussion, the authors begin by comparing the environmental advantages and disadvantages of biomass-derived energy relative to other energy alternatives such as coal, hydropower, nuclear power, oil/gasoline, natural gas and photovoltaics

  19. Improved Free-Energy Landscape Quantification Illustrated with a Computationally Designed Protein-Ligand Interaction.

    Science.gov (United States)

    Van Patten, William J; Walder, Robert; Adhikari, Ayush; Okoniewski, Stephen R; Ravichandran, Rashmi; Tinberg, Christine E; Baker, David; Perkins, Thomas T

    2018-01-05

    Quantifying the energy landscape underlying protein-ligand interactions leads to an enhanced understanding of molecular recognition. A powerful yet accessible single-molecule technique is atomic force microscopy (AFM)-based force spectroscopy, which generally yields the zero-force dissociation rate constant (k off ) and the distance to the transition state (Δx ≠ ). Here, we introduce an enhanced AFM assay and apply it to probe the computationally designed protein DIG10.3 binding to its target ligand, digoxigenin. Enhanced data quality enabled an analysis that yielded the height of the transition state (ΔG ≠ =6.3±0.2 kcal mol -1 ) and the shape of the energy barrier at the transition state (linear-cubic) in addition to the traditional parameters [k off (=4±0.1×10 -4  s -1 ) and Δx ≠ (=8.3±0.1 Å)]. We expect this automated and relatively rapid assay to provide a more complete energy landscape description of protein-ligand interactions and, more broadly, the diverse systems studied by AFM-based force spectroscopy. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Conference on landscape impacts of wind energy and local acceptance: France-Germany crossed views

    International Nuclear Information System (INIS)

    Bouscatel, Jerome; Olagne, Regis; Derkenne, Chantal; Galiano, Mila; Mayer, Joerg; Ratzbor, Guenter; Laborgne, Pia; Nadai, Alain; Ratouis, Marie-Odile; Schoebel-Rutschmann, Soeren; Petit, Jean-Francois; Guennewig, Dieter; Portales, David

    2008-01-01

    The French-German office for Renewable energies (OFAEnR) organised a conference on the landscape impacts of wind energy. In the framework of this French-German exchange of experience, more than 100 participants exchanged views on the environmental impact of wind farms and the opinion of residents. This document brings together the available presentations (slides) made during this event: 1 - French people and wind energy (Mila Galiano); 2 - Wind energy acceptance in Germany: an essential factor for the wind industry development (Joerg Mayer); 3 - Taking into account landscapes and residents in the development of wind farms: a France-Germany comparison (Pia Laborgne, Alain Nadai); 3 - Wind energy development supervision thanks to territorial planning in Germany (Guenter Ratzbor); 4 - Landscape challenges in wind energy development: point of view and role of a state decentralised department (Marie-Odile Ratouis); 5 - Park or landscape - Wind turbines as elements of the cultural landscape (Soeren Schoebel-Rutschmann); 6 - How should a developer approach the 'landscape' aspect when foreseeing a wind energy project installation (Jean-Francois Petit); 7 - More consensual wind energy projects along highways, railways and overhead power lines? (Dieter Guennewig); 8 - The 'wings top': un example of participatory and citizen's project (David Portales)

  1. A new heuristic method for approximating the number of local minima in partial RNA energy landscapes.

    Science.gov (United States)

    Albrecht, Andreas A; Day, Luke; Abdelhadi Ep Souki, Ouala; Steinhöfel, Kathleen

    2016-02-01

    The analysis of energy landscapes plays an important role in mathematical modelling, simulation and optimisation. Among the main features of interest are the number and distribution of local minima within the energy landscape. Granier and Kallel proposed in 2002 a new sampling procedure for estimating the number of local minima. In the present paper, we focus on improved heuristic implementations of the general framework devised by Granier and Kallel with regard to run-time behaviour and accuracy of predictions. The new heuristic method is demonstrated for the case of partial energy landscapes induced by RNA secondary structures. While the computation of minimum free energy RNA secondary structures has been studied for a long time, the analysis of folding landscapes has gained momentum over the past years in the context of co-transcriptional folding and deeper insights into cell processes. The new approach has been applied to ten RNA instances of length between 99 nt and 504 nt and their respective partial energy landscapes defined by secondary structures within an energy offset ΔE above the minimum free energy conformation. The number of local minima within the partial energy landscapes ranges from 1440 to 3441. Our heuristic method produces for the best approximations on average a deviation below 3.0% from the true number of local minima. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Habitat and landscape characteristics underlying anuran community structure along an urban-rural gradient.

    Science.gov (United States)

    Pillsbury, Finn C; Miller, James R

    2008-07-01

    Urbanization has been cited as an important factor in worldwide amphibian declines, and although recent work has illustrated the important influence of broad-scale ecological patterns and processes on amphibian populations, little is known about the factors structuring amphibian communities in urban landscapes. We therefore examined amphibian community responses to wetland habitat availability and landscape characteristics along an urban-rural gradient in central Iowa, USA, a region experiencing rapid suburban growth. We conducted call surveys at 61 wetlands to estimate anuran calling activity, and quantified wetland habitat structure and landscape context. We used canonical correspondence analysis (CCA) to examine patterns in anuran community structure and identify the most important variables associated with those patterns. Urban density at the landscape scale had a significant negative influence on overall anuran abundance and diversity. While every species exhibited a decrease in abundance with increasing urban density, this pattern was especially pronounced for species requiring post-breeding upland habitats. Anurans most affected by urbanization were those associated with short hydroperiods, early breeding activity, and substantial upland habitat use. We suggest that broad-scale landscape fragmentation is an important factor underlying anuran community structure in this region, possibly due to limitations on the accessibility of otherwise suitable habitat in fragmented urban landscapes. This study underscores the importance of a regional approach to amphibian conservation in urban and urbanizing areas; in fragmented landscapes, a network of interconnected wetland and upland habitats may be more likely to support a successful, diverse anuran community than will isolated sites.

  3. Energy Transition: Missed Opportunities and Emerging Challenges for Landscape Planning and Designing

    Directory of Open Access Journals (Sweden)

    Renée M. de Waal

    2014-07-01

    Full Text Available Making the shift from fossil fuels to renewable energy seems inevitable. Because energy transition poses new challenges and opportunities to the discipline of landscape architecture, the questions addressed in this paper are: (1 what landscape architects can learn from successful energy transitions in Güssing, Jühnde and Samsø; and (2 to what extent landscape architecture (or other spatial disciplines contributed to energy transition in the aforementioned cases. An exploratory, comparative case study was conducted to identify differences and similarities among the cases, to answer the research questions, and to formulate recommendations for further research and practice. The comparison indicated that the realized renewable energy systems are context-dependent and, therefore, specifically designed to meet the respective energy demand, making use of the available potentials for renewable energy generation and efficiency. Further success factors seemed to be the presence of (local frontrunners and a certain degree of citizen participation. The relatively smooth implementation of renewable energy technologies in Jühnde and on Samsø may indicate the importance of careful and (partly institutionalized consideration of landscape impact, siting and design. Comparing the cases against the literature demonstrated that landscape architects were not as involved as they, theoretically, could have been. However, particularly when the aim is sustainable development, rather than “merely” renewable energy provision, the integrative concept of “sustainable energy landscapes” can be the arena where landscape architecture and other disciplines meet to pursue global sustainability goals, while empowering local communities and safeguarding landscape quality.

  4. Changes of Bulgarian Coastal Dune Landscape under Anthropogenic Impact

    Science.gov (United States)

    Palazov, A.; Young, R.; Stancheva, M.; Stanchev, H.

    2012-04-01

    At one time large sand dune formations were widely distributed along the Bulgarian coast. However, due to increased urbanization in the coastal zone, the areas of total dune landscape has been constantly reduced. Dunes presently comprise only 10% of the entire 412 km long coastline of Bulgaria: they embrace a total length of 38.57 km and a total area of 8.78 km2 Important tasks in dune protection are identification of landscape changes for a certain period of time and accurate delineation of sand dune areas. The present research traces sand dune changes along the Bulgarian Black Sea coast over a 27 year period (1983-2010). This period includes also the time of expanded tourist boom and overbuilding of the coastal zone, and respectively presents the largest dune changes and reductions. Based on the landscape change analyst in GIS environment the study also aims to explore the importance of different natural and human factors in driving the observed dune alterations and destruction. To detect and assess dune changes during the last 3 decades, we used data for sand dunes derived from several sources at different time periods in order to compare changes in shoreline positions, dune contours and areas: i) Topographic maps in 1:5,000 scale from 1983; ii) Modern Very High Resolution orthophotographs from 2006 and 2010; iii) QuickBird Very High Resolution satellite images from 2009; iv) Statistical information for population and tourist infrastructure is also used to consider the influence of human pressure and hotel developments on the dune dynamics. In addition, for more detailed description and visualization of main dune types, digital photos have been taken at many parts of the Bulgarian coast. The study was performed in GIS environment. Based on the results obtained the dunes along the Bulgarian coast were divided into three main groups with relation to the general factors responsible for their alterations: i) Dunes that have decreased in result of shoreline retreat

  5. The energy landscape of uranyl-peroxide species

    Energy Technology Data Exchange (ETDEWEB)

    Tiferet, Eitan [Peter A. Rock Thermochemistry Laboratory, University of California, Davis, CA (United States); Nuclear Research Center - Negev, Be' er-Sheva (Israel); Gil, Adria; Bo, Carles [Institute of Chemical Research of Catalonia (ICIQ), Tarragona (Spain); Departament de Quimica Fisica i Inorganica, Universitat Rovira i Virgil, Tarragona (Spain); Shvareva, Tatiana Y.; Navrotsky, Alexandra [Peter A. Rock Thermochemistry Laboratory, University of California, Davis, CA (United States); Nyman, May [Department of Chemistry, Oregon State University, Corvallis, OR (United States)

    2014-03-24

    Nanoscale uranyl peroxide clusters containing UO{sub 2}{sup 2+} groups bonded through peroxide bridges to form polynuclear molecular species (polyoxometalates) exist both in solution and in the solid state. There is an extensive family of clusters containing 28 uranium atoms (U{sub 28} clusters), with an encapsulated anion in the center, for example, [UO{sub 2}(O{sub 2}){sub 3-x}(OH){sub x}{sup 4-}], [Nb(O{sub 2}){sub 4}{sup 3-}], or [Ta(O{sub 2}){sub 4}{sup 3-}]. The negative charge of these clusters is balanced by alkali ions, both encapsulated, and located exterior to the cluster. The present study reports measurement of enthalpy of formation for two such U{sub 28} compounds, one of which is uranyl centered and the other is peroxotantalate centered. The [Ta(O{sub 2}){sub 4}]-centered U{sub 28} capsule is energetically more stable than the [(UO{sub 2})(O{sub 2}){sub 3}]-centered capsule. These data, along with our prior studies on other uranyl-peroxide solids, are used to explore the energy landscape and define thermochemical trends in alkali-uranyl-peroxide systems. It was suggested that the energetic role of charge-balancing alkali ions and their electrostatic interactions with the negatively charged uranyl-peroxide species is the dominant factor in defining energetic stability. These experimental data were supported by DFT calculations, which agree that the [Ta(O{sub 2}){sub 4}]-centered U{sub 28} capsule is more stable than the uranyl-centered capsule. Moreover, the relative stability is controlled by the interactions of the encapsulated alkalis with the encapsulated anion. Thus, the role of alkali-anion interactions was shown to be important at all length scales of uranyl-peroxide species: in both comparing clusters to clusters; and clusters to monomers or extended solids. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Threshold Research on Highway Length under Typical Landscape Patterns Based on Drivers’ Physiological Performance

    Directory of Open Access Journals (Sweden)

    Xia Zhao

    2015-01-01

    Full Text Available The appropriately landscaped highway scenes may not only help improve road safety and comfort but also help protect ecological environment. Yet there is very little research data on highway length threshold with consideration of distinctive landscape patterns. Against this backdrop, the paper aims to quantitatively analyze highway landscape’s effect on driving behavior based on drivers’ physiological performance and quantify highway length thresholds under three typical landscape patterns, namely, “open,” “semiopen,” and “vertical” ones. The statistical analysis was based on data collected in a driving simulator and electrocardiograph. Specifically, vehicle-related data, ECG data, and supplemental subjective stress perception were collected. The study extracted two characteristic indices, lane deviation and LF/HF, and extrapolated the drivers’ U-shaped physiological response to landscape patterns. Models on highway length were built based on LF/HF’s variation trend with highway length. The results revealed that the theoretical highway length threshold tended to increase when the landscape pattern was switched to open, semiopen, and vertical ones. And the reliability and accuracy of the results were validated by questionnaires and field operational tests. Findings from this research will assist practitioners in taking active environmental countermeasures pertaining to different roadside landscape patterns.

  7. Preservation of a Preglacial Landscape Under the Center of the Greenland Ice Sheet

    Science.gov (United States)

    Bierman, Paul R.; Corbett, Lee B.; Graly, Joseph A.; Neumann, Thomas Allen; Lini, Andrea; Crosby, Benjamin T.; Rood, Dylan H.

    2014-01-01

    Continental ice sheets typically sculpt landscapes via erosion; under certain conditions, ancient landscapes can be preserved beneath ice and can survive extensive and repeated glaciation. We used concentrations of atmospherically produced cosmogenic beryllium-10, carbon, and nitrogen to show that ancient soil has been preserved in basal ice for millions of years at the center of the ice sheet at Summit, Greenland. This finding suggests ice sheet stability through the Pleistocene (i.e., the past 2.7 million years). The preservation of this soil implies that the ice has been non-erosive and frozen to the bed for much of that time, that there was no substantial exposure of central Greenland once the ice sheet became fully established, and that preglacial landscapes can remain preserved for long periods under continental ice sheets

  8. Aggregating energy flexibilities under constraints

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Pedersen, Torben Bach; Abello, Alberto

    2016-01-01

    The flexibility of individual energy prosumers (producers and/or consumers) has drawn a lot of attention in recent years. Aggregation of such flexibilities provides prosumers with the opportunity to directly participate in the energy market and at the same time reduces the complexity of scheduling...... and amount dimensions. We define the problem of aggregating FOs taking into account grid power constraints. We also propose two constraint-based aggregation techniques that efficiently aggregate FOs while retaining flexibility. We show through a comprehensive evaluation that our techniques, in contrast...

  9. PolyUbiquitin chain linkage topology selects the functions from the underlying binding landscape.

    Directory of Open Access Journals (Sweden)

    Yong Wang

    2014-07-01

    Full Text Available Ubiquitin (Ub can generate versatile molecular signals and lead to different celluar fates. The functional poly-valence of Ub is believed to be resulted from its ability to form distinct polymerized chains with eight linkage types. To provide a full picture of ubiquitin code, we explore the binding landscape of two free Ub monomers and also the functional landscapes of of all eight linkage types by theoretical modeling. Remarkably, we found that most of the compact structures of covalently connected dimeric Ub chains (diUbs pre-exist on the binding landscape. These compact functional states were subsequently validated by corresponding linkage models. This leads to the proposal that the folding architecture of Ub monomer has encoded all functional states into its binding landscape, which is further selected by different topologies of polymeric Ub chains. Moreover, our results revealed that covalent linkage leads to symmetry breaking of interfacial interactions. We further propose that topological constraint not only limits the conformational space for effective switching between functional states, but also selects the local interactions for realizing the corresponding biological function. Therefore, the topological constraint provides a way for breaking the binding symmetry and reaching the functional specificity. The simulation results also provide several predictions that qualitatively and quantitatively consistent with experiments. Importantly, the K48 linkage model successfully predicted intermediate states. The resulting multi-state energy landscape was further employed to reconcile the seemingly contradictory experimental data on the conformational equilibrium of K48-diUb. Our results further suggest that hydrophobic interactions are dominant in the functional landscapes of K6-, K11-, K33- and K48 diUbs, while electrostatic interactions play a more important role in the functional landscapes of K27, K29, K63 and linear linkages.

  10. PolyUbiquitin chain linkage topology selects the functions from the underlying binding landscape.

    Science.gov (United States)

    Wang, Yong; Tang, Chun; Wang, Erkang; Wang, Jin

    2014-07-01

    Ubiquitin (Ub) can generate versatile molecular signals and lead to different celluar fates. The functional poly-valence of Ub is believed to be resulted from its ability to form distinct polymerized chains with eight linkage types. To provide a full picture of ubiquitin code, we explore the binding landscape of two free Ub monomers and also the functional landscapes of of all eight linkage types by theoretical modeling. Remarkably, we found that most of the compact structures of covalently connected dimeric Ub chains (diUbs) pre-exist on the binding landscape. These compact functional states were subsequently validated by corresponding linkage models. This leads to the proposal that the folding architecture of Ub monomer has encoded all functional states into its binding landscape, which is further selected by different topologies of polymeric Ub chains. Moreover, our results revealed that covalent linkage leads to symmetry breaking of interfacial interactions. We further propose that topological constraint not only limits the conformational space for effective switching between functional states, but also selects the local interactions for realizing the corresponding biological function. Therefore, the topological constraint provides a way for breaking the binding symmetry and reaching the functional specificity. The simulation results also provide several predictions that qualitatively and quantitatively consistent with experiments. Importantly, the K48 linkage model successfully predicted intermediate states. The resulting multi-state energy landscape was further employed to reconcile the seemingly contradictory experimental data on the conformational equilibrium of K48-diUb. Our results further suggest that hydrophobic interactions are dominant in the functional landscapes of K6-, K11-, K33- and K48 diUbs, while electrostatic interactions play a more important role in the functional landscapes of K27, K29, K63 and linear linkages.

  11. Golf-course and funnel energy landscapes: Protein folding concepts in martensites.

    Science.gov (United States)

    Shankaraiah, N

    2017-06-01

    We use protein folding energy landscape concepts such as golf course and funnel to study re-equilibration in athermal martensites under systematic temperature quench Monte Carlo simulations. On quenching below a transition temperature, the seeded high-symmetry parent-phase austenite that converts to the low-symmetry product-phase martensite, through autocatalytic twinning or elastic photocopying, has both rapid conversions and incubation delays in the temperature-time-transformation phase diagram. We find the rapid (incubation delays) conversions at low (high) temperatures arises from the presence of large (small) size of golf-course edge that has the funnel inside for negative energy states. In the incubating state, the strain structure factor enters into the Brillouin-zone golf course through searches for finite transitional pathways which close off at the transition temperature with Vogel-Fulcher divergences that are insensitive to Hamiltonian energy scales and log-normal distributions, as signatures of dominant entropy barriers. The crossing of the entropy barrier is identified through energy occupancy distributions, Monte Carlo acceptance fractions, heat emission, and internal work.

  12. Energy landscape analysis of the subcortical brain network unravels system properties beneath resting state dynamics.

    Science.gov (United States)

    Kang, Jiyoung; Pae, Chongwon; Park, Hae-Jeong

    2017-04-01

    The configuration of the human brain system at rest, which is in a transitory phase among multistable states, remains unknown. To investigate the dynamic systems properties of the human brain at rest, we constructed an energy landscape for the state dynamics of the subcortical brain network, a critical center that modulates whole brain states, using resting state fMRI. We evaluated alterations in energy landscapes following perturbation in network parameters, which revealed characteristics of the state dynamics in the subcortical brain system, such as maximal number of attractors, unequal temporal occupations, and readiness for reconfiguration of the system. Perturbation in the network parameters, even those as small as the ones in individual nodes or edges, caused a significant shift in the energy landscape of brain systems. The effect of the perturbation on the energy landscape depended on the network properties of the perturbed nodes and edges, with greater effects on hub nodes and hubs-connecting edges in the subcortical brain system. Two simultaneously perturbed nodes produced perturbation effects showing low sensitivity in the interhemispheric homologous nodes and strong dependency on the more primary node among the two. This study demonstrated that energy landscape analysis could be an important tool to investigate alterations in brain networks that may underlie certain brain diseases, or diverse brain functions that may emerge due to the reconfiguration of the default brain network at rest. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Landscape Capacity and Social Attitudes towards Wind Energy Projects in Belgium

    OpenAIRE

    Van Rompaey, Anton; Schmitz, Serge; Kesteloot, Chris; Peeters, Karolien; Moens, Bruno; Van Hemelrijck, Hendrik; Vanderheyden, Vincent; Loopmans, Maarten; Vanden Broucke, Steven

    2011-01-01

    The present energy crisis and the awareness of the human impact on climate change have boosted the public debate on the accelerated deployment of renewable energy sources. The objective of this research project is to analyse and assess the landscape capacity and social attitudes towards wind energy parks in Belgium, especially in non-urban and non-industrial sites. This research project starts from the observation that a sustainable production of energy, relying on renewable resources, sh...

  14. Linking habitat selection to fitness-related traits in herbivores: the role of the energy landscape

    Science.gov (United States)

    Ryan A. Long; R. T. Bowyer; Warren P. Porter; Paul Mathewson; Kevin L. Monteith; Scott L. Findholt; Brian L. Dick; John G. Kie

    2016-01-01

    Animals may partially overcome environmental constraints on fitness by behaviorally adjusting their exposure to costs and supplies of energy. Few studies, however, have linked spatiotemporal variation in the energy landscape to behaviorally mediated measures of performance that ostensibly influence individual fitness. We hypothesized that strength of selection by North...

  15. Impacts of renewable energy on landscape. Alternative of offshore wind in marine areas

    Directory of Open Access Journals (Sweden)

    Francesca Moraci

    2014-01-01

    Full Text Available The effects determined in the landscape by plants powered by renewable sources represent some unresolved issues in terms of visual and landscape impact mitigation in general. These aspects relate to the landscape are recognized in all types of impact with due attention to the various components and dynamics involved identifiable in the landscape of reference.The wind power plants, in particular, while making unquestionable environmental benefits thanks to the production of energy from renewable sources, but imposes a significant cost to the landscape with the installation of wind turbines in contexts necessarily favorable to impact,  interrupting the skyline, creating territorial discontinuities, "subtracting" and altering the landscape in the absence of effective mitigation works.The environmental compatibility of the proposed solutions depends primarily on the location of wind farms.Is necessary indicate  an overall strategy, a shared model of planning and land management, as in other European countries such as Denmark, Germany, France and the United Kingdom where the choice of locating wind farms has resulted in a new draft territory, construction and redesign of the landscape.

  16. Physical mechanism of mind changes and tradeoffs among speed, accuracy, and energy cost in brain decision making: Landscape, flux, and path perspectives

    International Nuclear Information System (INIS)

    Yan Han; Wang Jin; Zhang Kun

    2016-01-01

    Cognitive behaviors are determined by underlying neural networks. Many brain functions, such as learning and memory, have been successfully described by attractor dynamics. For decision making in the brain, a quantitative description of global attractor landscapes has not yet been completely given. Here, we developed a theoretical framework to quantify the landscape associated with the steady state probability distributions and associated steady state curl flux, measuring the degree of non-equilibrium through the degree of detailed balance breaking for decision making. We quantified the decision-making processes with optimal paths from the undecided attractor states to the decided attractor states, which are identified as basins of attractions, on the landscape. Both landscape and flux determine the kinetic paths and speed. The kinetics and global stability of decision making are explored by quantifying the landscape topography through the barrier heights and the mean first passage time. Our theoretical predictions are in agreement with experimental observations: more errors occur under time pressure. We quantitatively explored two mechanisms of the speed-accuracy tradeoff with speed emphasis and further uncovered the tradeoffs among speed, accuracy, and energy cost. Our results imply that there is an optimal balance among speed, accuracy, and the energy cost in decision making. We uncovered the possible mechanisms of changes of mind and how mind changes improve performance in decision processes. Our landscape approach can help facilitate an understanding of the underlying physical mechanisms of cognitive processes and identify the key factors in the corresponding neural networks. (paper)

  17. The inverted free energy landscape of an intrinsically disordered peptide by simulations and experiments.

    Science.gov (United States)

    Granata, Daniele; Baftizadeh, Fahimeh; Habchi, Johnny; Galvagnion, Celine; De Simone, Alfonso; Camilloni, Carlo; Laio, Alessandro; Vendruscolo, Michele

    2015-10-26

    The free energy landscape theory has been very successful in rationalizing the folding behaviour of globular proteins, as this representation provides intuitive information on the number of states involved in the folding process, their populations and pathways of interconversion. We extend here this formalism to the case of the Aβ40 peptide, a 40-residue intrinsically disordered protein fragment associated with Alzheimer's disease. By using an advanced sampling technique that enables free energy calculations to reach convergence also in the case of highly disordered states of proteins, we provide a precise structural characterization of the free energy landscape of this peptide. We find that such landscape has inverted features with respect to those typical of folded proteins. While the global free energy minimum consists of highly disordered structures, higher free energy regions correspond to a large variety of transiently structured conformations with secondary structure elements arranged in several different manners, and are not separated from each other by sizeable free energy barriers. From this peculiar structure of the free energy landscape we predict that this peptide should become more structured and not only more compact, with increasing temperatures, and we show that this is the case through a series of biophysical measurements.

  18. Control of the Effective Free-Energy Landscape in a Frustrated Magnet by a Field Pulse

    Science.gov (United States)

    Wan, Yuan; Moessner, Roderich

    2017-10-01

    Thermal fluctuations can lift the degeneracy of a ground state manifold, producing a free-energy landscape without accidentally degenerate minima. In a process known as order by disorder, a subset of states incorporating symmetry breaking may be selected. Here, we show that such a free-energy landscape can be controlled in a nonequilibrium setting as the slow motion within the ground state manifold is governed by the fast modes out of it. For the paradigmatic case of the classical pyrochlore X Y antiferromagnet, we show that a uniform magnetic field pulse can excite these fast modes to generate a tunable effective free-energy landscape with minima at thermodynamically unstable portions of the ground state manifold.

  19. Another possible energy landscape; Un autre paysage energetique possible

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-06-01

    This analysis presents the national energy balances from the national energy accounting. The first part presents the accounting analysis on the electric power consumption and production in France. The second part deals with the global energy accounting, for the energy sources and utilization, together. From these analysis the authors show how the global energy efficiency of production and utilization is possible. Solutions allowing the reduction of the non renewable energies consumption and solution for the nuclear power phaseout are also proposed. (A.L.B.)

  20. Frustration in the energy landscapes of multidomain protein misfolding.

    Science.gov (United States)

    Zheng, Weihua; Schafer, Nicholas P; Wolynes, Peter G

    2013-01-29

    Frustration from strong interdomain interactions can make misfolding a more severe problem in multidomain proteins than in single-domain proteins. On the basis of bioinformatic surveys, it has been suggested that lowering the sequence identity between neighboring domains is one of nature's solutions to the multidomain misfolding problem. We investigate folding of multidomain proteins using the associative-memory, water-mediated, structure and energy model (AWSEM), a predictive coarse-grained protein force field. We find that reducing sequence identity not only decreases the formation of domain-swapped contacts but also decreases the formation of strong self-recognition contacts between β-strands with high hydrophobic content. The ensembles of misfolded structures that result from forming these amyloid-like interactions are energetically disfavored compared with the native state, but entropically favored. Therefore, these ensembles are more stable than the native ensemble under denaturing conditions, such as high temperature. Domain-swapped contacts compete with self-recognition contacts in forming various trapped states, and point mutations can shift the balance between the two types of interaction. We predict that multidomain proteins that lack these specific strong interdomain interactions should fold reliably.

  1. Integrating landscape genomics and spatially explicit approaches to detect loci under selection in clinal populations.

    Science.gov (United States)

    Jones, Matthew R; Forester, Brenna R; Teufel, Ashley I; Adams, Rachael V; Anstett, Daniel N; Goodrich, Betsy A; Landguth, Erin L; Joost, Stéphane; Manel, Stéphanie

    2013-12-01

    Uncovering the genetic basis of adaptation hinges on the ability to detect loci under selection. However, population genomics outlier approaches to detect selected loci may be inappropriate for clinal populations or those with unclear population structure because they require that individuals be clustered into populations. An alternate approach, landscape genomics, uses individual-based approaches to detect loci under selection and reveal potential environmental drivers of selection. We tested four landscape genomics methods on a simulated clinal population to determine their effectiveness at identifying a locus under varying selection strengths along an environmental gradient. We found all methods produced very low type I error rates across all selection strengths, but elevated type II error rates under "weak" selection. We then applied these methods to an AFLP genome scan of an alpine plant, Campanula barbata, and identified five highly supported candidate loci associated with precipitation variables. These loci also showed spatial autocorrelation and cline patterns indicative of selection along a precipitation gradient. Our results suggest that landscape genomics in combination with other spatial analyses provides a powerful approach for identifying loci potentially under selection and explaining spatially complex interactions between species and their environment. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  2. Pollution Under Environmental Regulation in Energy Markets

    CERN Document Server

    Gullì, Francesco

    2013-01-01

    Pollution Under Environmental Regulation in Energy Markets provides a study of environmental regulation when energy markets are imperfectly competitive. This theoretical treatment focuses on three relevant cases of energy markets. First, the residential space heating sector where hybrid regulation such as taxation and emissions trading together are possible. Second, the electricity market where transactions are organized in the form of multi-period auctions. Third, namely natural gas (input) and electricity (output) markets where there is combined imperfect competition in vertical related energy markets.   The development of free or low carbon technologies supported by energy policies, aiming at increasing security of supply, is also explored whilst considering competition policies that reduce market power in energy markets thus improving market efficiency. Pollution Under Environmental Regulation in Energy Markets discusses the key issues of whether imperfect competition can lessen the ability of environmen...

  3. Deciphering hierarchical features in the energy landscape of adenylate kinase folding/unfolding

    Science.gov (United States)

    Taylor, J. Nicholas; Pirchi, Menahem; Haran, Gilad; Komatsuzaki, Tamiki

    2018-03-01

    Hierarchical features of the energy landscape of the folding/unfolding behavior of adenylate kinase, including its dependence on denaturant concentration, are elucidated in terms of single-molecule fluorescence resonance energy transfer (smFRET) measurements in which the proteins are encapsulated in a lipid vesicle. The core in constructing the energy landscape from single-molecule time-series across different denaturant concentrations is the application of rate-distortion theory (RDT), which naturally considers the effects of measurement noise and sampling error, in combination with change-point detection and the quantification of the FRET efficiency-dependent photobleaching behavior. Energy landscapes are constructed as a function of observation time scale, revealing multiple partially folded conformations at small time scales that are situated in a superbasin. As the time scale increases, these denatured states merge into a single basin, demonstrating the coarse-graining of the energy landscape as observation time increases. Because the photobleaching time scale is dependent on the conformational state of the protein, possible nonequilibrium features are discussed, and a statistical test for violation of the detailed balance condition is developed based on the state sequences arising from the RDT framework.

  4. 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.

  5. The forgotten D : challenges of addressing forest degradation in complex mosaic landscapes under REDD

    OpenAIRE

    Mertz, O.; Muller, D.; Sikor, T.; Hett, C.; Heinimann, A.; Castella, Jean-Christophe; Lestrelin, Guillaume; Ryan, C. M.; Reay, D. S.; Schmidt-Vogt, D.; Danielsen, F.; Theilade, I.; van Noordwijk, M.; Verchot, L. V.; Burgess, N. D.

    2012-01-01

    International climate negotiations have stressed the importance of considering emissions from forest degradation under the planned REDD+ (Reducing Emissions from Deforestation and forest Degradation + enhancing forest carbon stocks) mechanism. However, most research, pilot-REDD+ projects and carbon certification agencies have focused on deforestation and there appears to be a gap in knowledge on complex mosaic landscapes containing degraded forests, smallholder agriculture, agroforestry and p...

  6. Enhanced conformational sampling to visualize a free-energy landscape of protein complex formation.

    Science.gov (United States)

    Iida, Shinji; Nakamura, Haruki; Higo, Junichi

    2016-06-15

    We introduce various, recently developed, generalized ensemble methods, which are useful to sample various molecular configurations emerging in the process of protein-protein or protein-ligand binding. The methods introduced here are those that have been or will be applied to biomolecular binding, where the biomolecules are treated as flexible molecules expressed by an all-atom model in an explicit solvent. Sampling produces an ensemble of conformations (snapshots) that are thermodynamically probable at room temperature. Then, projection of those conformations to an abstract low-dimensional space generates a free-energy landscape. As an example, we show a landscape of homo-dimer formation of an endothelin-1-like molecule computed using a generalized ensemble method. The lowest free-energy cluster at room temperature coincided precisely with the experimentally determined complex structure. Two minor clusters were also found in the landscape, which were largely different from the native complex form. Although those clusters were isolated at room temperature, with rising temperature a pathway emerged linking the lowest and second-lowest free-energy clusters, and a further temperature increment connected all the clusters. This exemplifies that the generalized ensemble method is a powerful tool for computing the free-energy landscape, by which one can discuss the thermodynamic stability of clusters and the temperature dependence of the cluster networks. © 2016 The Author(s).

  7. Free-energy landscape of protein oligomerization from atomistic simulations

    Science.gov (United States)

    Barducci, Alessandro; Bonomi, Massimiliano; Prakash, Meher K.; Parrinello, Michele

    2013-01-01

    In the realm of protein–protein interactions, the assembly process of homooligomers plays a fundamental role because the majority of proteins fall into this category. A comprehensive understanding of this multistep process requires the characterization of the driving molecular interactions and the transient intermediate species. The latter are often short-lived and thus remain elusive to most experimental investigations. Molecular simulations provide a unique tool to shed light onto these complex processes complementing experimental data. Here we combine advanced sampling techniques, such as metadynamics and parallel tempering, to characterize the oligomerization landscape of fibritin foldon domain. This system is an evolutionarily optimized trimerization motif that represents an ideal model for experimental and computational mechanistic studies. Our results are fully consistent with previous experimental nuclear magnetic resonance and kinetic data, but they provide a unique insight into fibritin foldon assembly. In particular, our simulations unveil the role of nonspecific interactions and suggest that an interplay between thermodynamic bias toward native structure and residual conformational disorder may provide a kinetic advantage. PMID:24248370

  8. From Extraction of Local Structures of Protein Energy Landscapes to Improved Decoy Selection in Template-Free Protein Structure Prediction

    Directory of Open Access Journals (Sweden)

    Nasrin Akhter

    2018-01-01

    Full Text Available Due to the essential role that the three-dimensional conformation of a protein plays in regulating interactions with molecular partners, wet and dry laboratories seek biologically-active conformations of a protein to decode its function. Computational approaches are gaining prominence due to the labor and cost demands of wet laboratory investigations. Template-free methods can now compute thousands of conformations known as decoys, but selecting native conformations from the generated decoys remains challenging. Repeatedly, research has shown that the protein energy functions whose minima are sought in the generation of decoys are unreliable indicators of nativeness. The prevalent approach ignores energy altogether and clusters decoys by conformational similarity. Complementary recent efforts design protein-specific scoring functions or train machine learning models on labeled decoys. In this paper, we show that an informative consideration of energy can be carried out under the energy landscape view. Specifically, we leverage local structures known as basins in the energy landscape probed by a template-free method. We propose and compare various strategies of basin-based decoy selection that we demonstrate are superior to clustering-based strategies. The presented results point to further directions of research for improving decoy selection, including the ability to properly consider the multiplicity of native conformations of proteins.

  9. From Extraction of Local Structures of Protein Energy Landscapes to Improved Decoy Selection in Template-Free Protein Structure Prediction.

    Science.gov (United States)

    Akhter, Nasrin; Shehu, Amarda

    2018-01-19

    Due to the essential role that the three-dimensional conformation of a protein plays in regulating interactions with molecular partners, wet and dry laboratories seek biologically-active conformations of a protein to decode its function. Computational approaches are gaining prominence due to the labor and cost demands of wet laboratory investigations. Template-free methods can now compute thousands of conformations known as decoys, but selecting native conformations from the generated decoys remains challenging. Repeatedly, research has shown that the protein energy functions whose minima are sought in the generation of decoys are unreliable indicators of nativeness. The prevalent approach ignores energy altogether and clusters decoys by conformational similarity. Complementary recent efforts design protein-specific scoring functions or train machine learning models on labeled decoys. In this paper, we show that an informative consideration of energy can be carried out under the energy landscape view. Specifically, we leverage local structures known as basins in the energy landscape probed by a template-free method. We propose and compare various strategies of basin-based decoy selection that we demonstrate are superior to clustering-based strategies. The presented results point to further directions of research for improving decoy selection, including the ability to properly consider the multiplicity of native conformations of proteins.

  10. The Landscape of Renewable Energies in Europe in 2030

    International Nuclear Information System (INIS)

    Cruciani, Michel

    2017-06-01

    The study analyses the European rules designed to promote renewable energy, highlighting their innovations and the difficulties they will raise. The study highlights the consequences of some of the measures envisaged and pays particular attention to the electricity market. On 30 November 2016, the European Commission issued a new set of proposals, the 'Clean Energy Package', covering a wide spectrum of activities. This study analyses the provisions of this package which aim at improving energy efficiency by 30% and giving renewable energy a share of 27% of consumption by 2030. In 2014, Member States had called for these objectives to be assessed for the entire European Union. Nevertheless the Commission wishes to obtain a mandate to check that each State makes an honest contribution to the collective effort. The study stresses that the 30% target for energy efficiency weakens the role of the CO 2 market. The simulations reveal that this weakness will benefit coal, which keeps in 2030 a higher share than it would have occupied with a target of 27%, whereas natural gas is penalized by a low CO 2 price. It also appears that by remaining too low, the price of CO 2 will discourage certain investments in favour of renewable energies that would have naturally emerged with a high price. Therefore it will be necessary to roll out costly public policies to trigger these investments, so that the share of these energies totals 27% by 2030. The simulations also show that the renewable energy target will be largely achieved through very rapid growth of wind and solar power. The proposals of 30 November 2016 hence are drafted to encourage the development of these two sectors by reforming the electricity market so that it establishes a price that is remunerative and reduces the need for public aid, while clearly reflecting the burdens generated by the different actors. It seems unlikely that the Member States will accept such a profound market reform as the Commission

  11. The relative importance of physical and biological energy in landscape evolution

    Science.gov (United States)

    Turowski, J. M.; Schwanghart, W.

    2017-12-01

    Landscapes are formed by the interplay of uplift and geomorphic processes, including interacting and competing physical and biological processes. For example, roots re-inforce soil and thereby stabilize hillslopes and the canopy cover of the forest may mediate the impact of precipitation. Furthermore, plants and animals act as geomorphic agents, directly altering landscape response and dynamics by their actions: tree roots may crack rocks, thus changing subsurface water flows and exposing fresh material for denudation; fungi excrete acids that accelerate rates of chemical weathering, and burrowing animals displace soil and rocks while digging holes for shelter or in search of food. Energetically, landscapes can be viewed as open systems in which topography stores potential energy above a base level. Tectonic processes add energy to the system by uplift and mechanically altering rock properties. Especially in unvegetated regions, erosion and transport by wind can be an important geomorphic process. Advection of atmospheric moisture in high altitudes provides potential energy that is converted by water fluxes through catchments. At the same time, the conversion of solar energy through atmospheric and biological processes drives primary production of living organisms. If we accept that biota influence geomorphic processes, then what is their energetic contribution to landscape evolution relative to physical processes? Using two case studies, we demonstrate that all components of energy input are negligible apart from biological production, quantified by net primary productivity (NPP) and potential energy conversion by water that is placed high up in the landscape as rainfall and leaves it as runoff. Assuming that the former is representative for biological energy and the latter for physical energy, we propose that the ratio of these two values can be used as a proxy for the relative importance of biological and physical processes in landscape evolution. All necessary

  12. Europe's battery: The making of the Alpine energy landscape, 1870-1955

    Science.gov (United States)

    Landry, Marc D., II

    This study examines the environmental history of hydropower development in the Alps from the mid-nineteenth to the mid-twentieth centuries. Analyzing government archival files, associational journals, conference proceedings, and published contemporary material from several Alpine countries, it seeks to determine how and why Europeans modified the Alpine landscape to generate hydropower, and to explore the consequences of these decisions. I argue that during this time period, Europeans thoroughly transformed the Alpine environment, creating what I call "Europe's Battery": a gigantic system for storing hydropower and distributing it on a continental scale. This study shows how nineteenth-century innovations in energy technology contributed to a dramatic shift in the perception of the Alps as a landscape of "white coal." It demonstrates how at the outset of electrification, Europeans modified Alpine waterways on an unprecedented scale in order to tap into the power of flowing Alpine water. I show how after the turn of the twentieth century, Europeans took advantage of the unique mountain environment to store water, first by converting existing lakes into reservoirs. The practice countered what was perceived to be the greatest disadvantage of white coal: its climate-influenced inconstancy. This study shows the importance of war, and especially the First World War, in the forging of the new Alpine landscape. Finally, this study illustrates how from the interwar period to the aftermath of the Second World War, Europeans put the finishing touches on the new Alpine energy landscape by creating large reservoirs behind dams and feeding Alpine hydroelectricity into a burgeoning European electricity grid. By 1955 the Alps had become one of the most important energy landscapes in Europe. This history of the Alpine energy landscape contributes to a number of historiographical fields. It represents an important chapter in the environmental history of one of the world's most

  13. Calculation of the Local Free Energy Landscape in the Restricted Region by the Modified Tomographic Method.

    Science.gov (United States)

    Chen, Changjun

    2016-03-31

    The free energy landscape is the most important information in the study of the reaction mechanisms of the molecules. However, it is difficult to calculate. In a large collective variable space, a molecule must take a long time to obtain the sufficient sampling during the simulation. To save the calculation quantity, decreasing the sampling region and constructing the local free energy landscape is required in practice. However, the restricted region in the collective variable space may have an irregular shape. Simply restricting one or more collective variables of the molecule cannot satisfy the requirement. In this paper, we propose a modified tomographic method to perform the simulation. First, it divides the restricted region by some hyperplanes and connects the centers of hyperplanes together by a curve. Second, it forces the molecule to sample on the curve and the hyperplanes in the simulation and calculates the free energy data on them. Finally, all the free energy data are combined together to form the local free energy landscape. Without consideration of the area outside the restricted region, this free energy calculation can be more efficient. By this method, one can further optimize the path quickly in the collective variable space.

  14. Towards the free energy landscape for catalysis in mammalian nitric oxide synthases.

    Science.gov (United States)

    Leferink, Nicole G H; Hay, Sam; Rigby, Stephen E J; Scrutton, Nigel S

    2015-08-01

    The general requirement for conformational sampling in biological electron transfer reactions catalysed by multi-domain redox systems has been emphasized in recent years. Crucially, we lack insight into the extent of the conformational space explored and the nature of the energy landscapes associated with these reactions. The nitric oxide synthases (NOS) produce the signalling molecule NO through a series of complex electron transfer reactions. There is accumulating evidence that protein domain dynamics and calmodulin binding are implicated in regulating electron flow from NADPH, through the FAD and FMN cofactors, to the haem oxygenase domain, where NO is generated. Simple models based on static crystal structures of the isolated reductase domain have suggested a role for large-scale motions of the FMN-binding domain in shuttling electrons from the reductase domain to the oxygenase domain. However, detailed insight into the higher-order domain architecture and dynamic structural transitions in NOS enzymes during enzyme turnover is lacking. In this review, we discuss the recent advances made towards mapping the catalytic free energy landscapes of NOS enzymes through integration of both structural techniques (e.g. cryo-electron microscopy) and biophysical techniques (e.g. pulsed-electron paramagnetic resonance). The general picture that emerges from these experiments is that NOS enzymes exist in an equilibrium of conformations, comprising a 'rugged' or 'frustrated' energy landscape, with a key regulatory role for calmodulin in driving vectorial electron transfer by altering the conformational equilibrium. A detailed understanding of these landscapes may provide new opportunities for discovery of isoform-specific inhibitors that bind at the dynamic interfaces of these multi-dimensional energy landscapes. © 2014 FEBS.

  15. Low Energy Supersymmetry from the Heterotic String Landscape

    CERN Document Server

    Lebedev, O; Raby, S; Ramos-Sanchez, S; Ratz, M; Vaudrevange, P K S; Wingerter, A; Lebedev, Oleg; Nilles, Hans-Peter; Raby, Stuart; Ramos-Sanchez, Saul; Ratz, Michael; Vaudrevange, Patrick K. S.; Wingerter, Akin

    2007-01-01

    We study possible correlations between properties of the observable and hidden sectors in heterotic string theory. Specifically, we analyze the case of the Z6-II orbifold compactification which produces a significant number of models with the spectrum of the supersymmetric standard model. We find that requiring realistic features does affect the hidden sector such that hidden sector gauge group factors SU(4) and SO(8) are favoured. In the context of gaugino condensation, this implies low energy supersymmetry breaking.

  16. Landscape management for sustainable supplies of bio energy feedstock and enhanced soil quality

    International Nuclear Information System (INIS)

    Douglas, K.; Muth, D.

    2013-01-01

    Agriculture can simultaneously address global food, feed, fiber, and energy challenges provided our soil, water, and air resources are not compromised in doing so. Our objective is to present a landscape management concept as an approach for integrating multiple bio energy feedstock sources into current crop production systems. This is done to show how multiple, increasing global challenges can be met in a sustainable manner. We discuss how collaborative research among Usda-Agricultural Research Service (ARS), US Department of Energy (DOE) Idaho National Laboratory (INL), several university extension and research partners, and industry representatives [known as the Renewable Energy Assessment Project (Reap) team] has led to the development of computer-based decision aids for guiding sustainable bio energy feedstock production. The decision aids, known initially as the Corn Stover Tool and more recently as the Landscape Environmental Assessment Framework (Leaf) are tools designed to recognize the importance of nature s diversity and can therefore be used to guide sustainable feedstock production without having negative impacts on critical ecosystem services. Using a 57 ha farm site in central Iowa, USA, we show how producer decisions regarding corn (Zea mays L.) stover harvest within the US Corn Belt can be made in a more sustainable manner. This example also supports Reap team conclusions that stover should not be harvested if average grain yields are less than 11 Mg ha-1 unless more balanced landscape management practices are implemented. The tools also illustrate the importance of sub-field management and site-specific stover harvest strategies

  17. Tropical amphibians in shifting thermal landscapes under land-use and climate change.

    Science.gov (United States)

    Nowakowski, A Justin; Watling, James I; Whitfield, Steven M; Todd, Brian D; Kurz, David J; Donnelly, Maureen A

    2017-02-01

    Land-cover and climate change are both expected to alter species distributions and contribute to future biodiversity loss. However, the combined effects of land-cover and climate change on assemblages, especially at the landscape scale, remain understudied. Lowland tropical amphibians may be particularly susceptible to changes in land cover and climate warming because many species have narrow thermal safety margins resulting from air and body temperatures that are close to their critical thermal maxima (CT max ). We examined how changing thermal landscapes may alter the area of thermally suitable habitat (TSH) for tropical amphibians. We measured microclimates in 6 land-cover types and CT max of 16 frog species in lowland northeastern Costa Rica. We used a biophysical model to estimate core body temperatures of frogs exposed to habitat-specific microclimates while accounting for evaporative cooling and behavior. Thermally suitable habitat area was estimated as the portion of the landscape where species CT max exceeded their habitat-specific maximum body temperatures. We projected changes in TSH area 80 years into the future as a function of land-cover change only, climate change only, and combinations of land-cover and climate-change scenarios representing low and moderate rates of change. Projected decreases in TSH area ranged from 16% under low emissions and reduced forest loss to 30% under moderate emissions and business-as-usual land-cover change. Under a moderate emissions scenario (A1B), climate change alone contributed to 1.7- to 4.5-fold greater losses in TSH area than land-cover change only, suggesting that future decreases in TSH from climate change may outpace structural habitat loss. Forest-restricted species had lower mean CT max than species that occurred in altered habitats, indicating that thermal tolerances will likely shape assemblages in changing thermal landscapes. In the face of ongoing land-cover and climate change, it will be critical to

  18. Modeling energy fluxes in heterogeneous landscapes employing a mosaic approach

    Science.gov (United States)

    Klein, Christian; Thieme, Christoph; Priesack, Eckart

    2015-04-01

    Recent studies show that uncertainties in regional and global climate and weather simulations are partly due to inadequate descriptions of the energy flux exchanges between the land surface and the atmosphere. One major shortcoming is the limitation of the grid-cell resolution, which is recommended to be about at least 3x3 km² in most models due to limitations in the model physics. To represent each individual grid cell most models select one dominant soil type and one dominant land use type. This resolution, however, is often too coarse in regions where the spatial diversity of soil and land use types are high, e.g. in Central Europe. An elegant method to avoid the shortcoming of grid cell resolution is the so called mosaic approach. This approach is part of the recently developed ecosystem model framework Expert-N 5.0. The aim of this study was to analyze the impact of the characteristics of two managed fields, planted with winter wheat and potato, on the near surface soil moistures and on the near surface energy flux exchanges of the soil-plant-atmosphere interface. The simulated energy fluxes were compared with eddy flux tower measurements between the respective fields at the research farm Scheyern, North-West of Munich, Germany. To perform these simulations, we coupled the ecosystem model Expert-N 5.0 to an analytical footprint model. The coupled model system has the ability to calculate the mixing ratio of the surface energy fluxes at a given point within one grid cell (in this case at the flux tower between the two fields). This approach accounts for the differences of the two soil types, of land use managements, and of canopy properties due to footprint size dynamics. Our preliminary simulation results show that a mosaic approach can improve modeling and analyzing energy fluxes when the land surface is heterogeneous. In this case our applied method is a promising approach to extend weather and climate models on the regional and on the global scale.

  19. Renewable energy policy and landscape management in Andalusia, Spain: The facts

    International Nuclear Information System (INIS)

    Prados, Maria-Jose

    2010-01-01

    Renewable energy has developed spectacularly in Spain since the European Union started a process of energy policy reform. A review of Spanish State legislation on renewable energies confirms that the success in installing renewable energy is attributable to public aid. Andalusia is one of the autonomous communities, which has simultaneously developed the legal framework and very successfully implemented the introduction of renewable power. When implementing the central government's policy, the Andalusian regional government prioritised increases in both surface cover by wind and solar plants (thermal and photovoltaic energy) and in the number of companies involved. However, this development of renewable energies took place without any proper integration into regional spatial and landscape planning. This paper explores renewable power implementation in Andalusia through regulatory measures put in place over the last decade to develop renewable energy systems and the way they can be managed alongside planning issues. The location of large-scale renewable plants has had consequences for territory in the socio-political context of renewable energy promotion. The main findings focus on renewable energy plant sprawl throughout rural areas in Andalusia with no clear effect on landscape management and no firm backing from the local population.

  20. Free Energy Landscapes of Alanine Oligopeptides in Rigid-Body and Hybrid Water Models.

    Science.gov (United States)

    Nayar, Divya; Chakravarty, Charusita

    2015-08-27

    Replica exchange molecular dynamics is used to study the effect of different rigid-body (mTIP3P, TIP4P, SPC/E) and hybrid (H1.56, H3.00) water models on the conformational free energy landscape of the alanine oligopeptides (acAnme and acA5nme), in conjunction with the CHARMM22 force field. The free energy landscape is mapped out as a function of the Ramachandran angles. In addition, various secondary structure metrics, solvation shell properties, and the number of peptide-solvent hydrogen bonds are monitored. Alanine dipeptide is found to have similar free energy landscapes in different solvent models, an insensitivity which may be due to the absence of possibilities for forming i-(i + 4) or i-(i + 3) intrapeptide hydrogen bonds. The pentapeptide, acA5nme, where there are three intrapeptide backbone hydrogen bonds, shows a conformational free energy landscape with a much greater degree of sensitivity to the choice of solvent model, though the three rigid-body water models differ only quantitatively. The pentapeptide prefers nonhelical, non-native PPII and β-sheet populations as the solvent is changed from SPC/E to the less tetrahedral liquid (H1.56) to an LJ-like liquid (H3.00). The pentapeptide conformational order metrics indicate a preference for open, solvent-exposed, non-native structures in hybrid solvent models at all temperatures of study. The possible correlations between the properties of solvent models and secondary structure preferences of alanine oligopeptides are discussed, and the competition between intrapeptide, peptide-solvent, and solvent-solvent hydrogen bonding is shown to be crucial in the relative free energies of different conformers.

  1. How common is the funnel-like energy landscape in protein-protein interactions?

    Science.gov (United States)

    Tovchigrechko, Andrei; Vakser, Ilya A.

    2001-01-01

    The goal of this study is to verify the concept of the funnel-like intermolecular energy landscape in protein–protein interactions by use of a series of computational experiments. Our preliminary analysis revealed the existence of the funnel in many protein–protein interactions. However, because of the uncertainties in the modeling of these interactions and the ambiguity of the analysis procedures, the detection of the funnels requires detailed quantitative approaches to the energy landscape analysis. A number of such approaches are presented in this study. We show that the funnel detection problem is equivalent to a problem of distinguishing between distributions of low-energy intermolecular matches in the funnel and in the low-frequency landscape fluctuations. If the fluctuations are random, the decision about whether the minimum is the funnel is equivalent to determining whether this minimum is significantly different from a would-be random one. A database of 475 nonredundant cocrystallized protein–protein complexes was used to re-dock the proteins by use of smoothed potentials. To detect the funnel, we developed a set of sophisticated models of random matches. The funnel was considered detected if the binding area was more populated by the low-energy docking predictions than by the matches generated in the random models. The number of funnels detected by use of different random models varied significantly. However, the results confirmed that the funnel may be the general feature in protein–protein association. PMID:11468354

  2. Specific Energy of Hard Coal Under Load

    Directory of Open Access Journals (Sweden)

    Bogusz Anna

    2015-03-01

    Full Text Available The article presents results of experimental tests of energy parameters of hard coals under loading, collected from research sites located within five main geologic structures of Upper Silesian Coal Basin (GZW - Main Trough, Main Anticline, Bytom Trough, Rybnik Trough and Chwałowice Trough. Coals from12 mines were analysed, starting with seams of group 200, through groups 400, 500, 600 and, finally, seams of group 700. Coal of each of the groups of seams underwent uniaxial compression stress of the energy parameters, in a servo-controlled testing machine MTS-810NEW, for the full range of strain of the tested coal samples. Based on the tests the dependence of different types of specific energy of longitudinal strain of coals on the value of uniaxial compression strength was determined. The dependence of the value of dissipated energy and kinetic energy of coals on the uniaxial compression strength was described with a linear function, both for coals which due to their age belong to various bed sand for various lithotypes of coal. An increase in the value of dissipated energy and in kinetic energy was observed, which was correlated with an increase in uniaxial compression strength of coal. The share of dissipated energy is dominant in the total energy of strain. Share of recoverable energy in the total energy of strain is small, independent of the compression strength of coals and is at most a few per cent high. In coals of low strength and dominant share of dissipated energy, share of recoverable energy is the biggest among the tested coals. It was shown that following an increase in compression strength the share of recoverable energy decreases, while the share of dissipated energy in the total energy increases. Further studies of specific energy of longitudinal strain of rocks in the full-range strain will be the next step inperfecting methodology of research into natural rock burst susceptibility of Carboniferous rock mass and changes in the

  3. The elastic free energy of a tandem modular protein under force.

    Science.gov (United States)

    Valle-Orero, Jessica; Eckels, Edward C; Stirnemann, Guillaume; Popa, Ionel; Berkovich, Ronen; Fernandez, Julio M

    2015-05-01

    Recent studies have provided a theoretical framework for including entropic elasticity in the free energy landscape of proteins under mechanical force. Accounting for entropic elasticity using polymer physics models has helped explain the hopping behavior seen in single molecule experiments in the low force regime. Here, we expand on the construction of the free energy of a single protein domain under force proposed by Berkovich et al. to provide a free energy landscape for N tandem domains along a continuous polypeptide. Calculation of the free energy of individual domains followed by their concatenation provides a continuous free energy landscape whose curvature is dominated by the worm-like chain at forces below 20 pN. We have validated our free energy model using Brownian dynamics and reproduce key features of protein folding. This free energy model can predict the effects of changes in the elastic properties of a multidomain protein as a consequence of biological modifications such as phosphorylation or the formation of disulfide bonds. This work lays the foundations for the modeling of tissue elasticity, which is largely determined by the properties of tandem polyproteins. Copyright © 2015. Published by Elsevier Inc.

  4. Low-dimensional, free-energy landscapes of protein-folding reactions by nonlinear dimensionality reduction

    Science.gov (United States)

    Das, Payel; Moll, Mark; Stamati, Hernán; Kavraki, Lydia E.; Clementi, Cecilia

    2006-01-01

    The definition of reaction coordinates for the characterization of a protein-folding reaction has long been a controversial issue, even for the “simple” case in which one single free-energy barrier separates the folded and unfolded ensemble. We propose a general approach to this problem to obtain a few collective coordinates by using nonlinear dimensionality reduction. We validate the usefulness of this method by characterizing the folding landscape associated with a coarse-grained protein model of src homology 3 as sampled by molecular dynamics simulations. The folding free-energy landscape projected on the few relevant coordinates emerging from the dimensionality reduction can correctly identify the transition-state ensemble of the reaction. The first embedding dimension efficiently captures the evolution of the folding process along the main folding route. These results clearly show that the proposed method can efficiently find a low-dimensional representation of a complex process such as protein folding. PMID:16785435

  5. Relationship between energy systems and landscapes. Guidelines and tools for design and management

    Directory of Open Access Journals (Sweden)

    Elisabetta Ginelli

    2014-10-01

    Full Text Available Landscapes undergoing conservation, valorisation, management and reconstruction policies, become a fundamental factor for the local/global development of natural, cultural, human and social potentials of territories. With the contribution of technological design culture, the research, having a strong multidisciplinary character, focuses on managing the relationship between energy systems and landscapes with the general aim of subverting and transforming apparent conflicts in synergies, in order to overcome a sectorial and segmented approach barely based on energy performances. Through the introduction of a complex multidimensional methodology of analysis and evaluation the goal of this work, is to develop standards of acceptability, meta-design criteria and guidelines for design, intro- ducing a methodology for multidimen- sional complex analysis and evaluation, to support Public Authorities.

  6. Low-dimensional, free-energy landscapes of protein-folding reactions by nonlinear dimensionality reduction

    OpenAIRE

    Das, Payel; Moll, Mark; Stamati, Hernán; Kavraki, Lydia E.; Clementi, Cecilia

    2006-01-01

    The definition of reaction coordinates for the characterization of a protein-folding reaction has long been a controversial issue, even for the “simple” case in which one single free-energy barrier separates the folded and unfolded ensemble. We propose a general approach to this problem to obtain a few collective coordinates by using nonlinear dimensionality reduction. We validate the usefulness of this method by characterizing the folding landscape associated with a coarse-grained protein mo...

  7. Forest restoration in a mixed-ownership landscape under climate change.

    Science.gov (United States)

    Ravenscroft, Catherine; Scheller, Robert M; Mladenoff, David J; White, Mark A

    2010-03-01

    The extent to which current landscapes deviate from the historical range of natural variability (RNV) is a common means of defining and ranking regional conservation targets. However, climate-induced shifts in forest composition may render obsolete restoration strategies and conservation targets based on historic climate conditions and disturbance regimes. We used a spatially explicit forest ecosystem model, LANDIS-II, to simulate the interaction of climate change and forest management in northeastern Minnesota, USA. We assessed the relevance of restoration strategies and conservation targets based on the RNV in the context of future climate change. Three climate scenarios (no climate change, low emissions, and high emissions) were simulated with three forest management scenarios: no harvest, current management, and a restoration-based approach where harvest activity mimicked the frequency, severity, and size distribution of historic natural disturbance regimes. Under climate change there was a trend toward homogenization of forest conditions due to the widespread expansion of systems dominated by maple (Acer spp.). White spruce (Picea glauca), balsam fir (Abies balsamea), and paper birch (Betula papyrifera) were extirpated from the landscape irrespective of management activity; additional losses of black spruce (P. mariana), red pine (Pinus resinosa), and jack pine (P. banksiana) were projected in the high-emissions scenario. In the restoration management scenario, retention and conversion to white pine (P. strobus) restricted maple expansion. But, widespread forest loss in the restoration scenario under high-emissions projections illustrates the potential pitfalls of implementing an RNV management approach in a system that is not compositionally similar to the historic reference condition. Given the uncertainty associated with climate change, ensuring a diversity of species and conditions within forested landscapes may be the most effective means of ensuring the

  8. A new approach to quantify semiochemical effects on insects based on energy landscapes.

    Directory of Open Access Journals (Sweden)

    Rory P Wilson

    Full Text Available Our ability to document insect preference for semiochemicals is pivotal in pest control as these agents can improve monitoring and be deployed within integrated pest management programmes for more efficacious control of pest species. However, methods used to date have drawbacks that limit their utility. We present and test a new concept for determining insect motivation to move towards, or away from, semiochemicals by noting direction and speed of movement as animals work against a defined energy landscape (environmentally dependent variation in the cost of transport requiring different powers to negotiate. We conducted trials with the pine weevils Hylobius abietis and peach-potato aphids Myzus persicae exposed to various attractants and repellents and placed so that they either moved up defined slopes against gravity or had to travel over variously rough surfaces.Linear Mixed Models demonstrated clear reductions in travel speed by insects moving along increasingly energetically taxing energy landscapes but also that responses varied according to different semiochemicals, thus highlighting the value of energy landscapes as a new concept to help measure insect motivation to access or avoid different attractants or repellents across individuals.New sensitive, detailed indicators of insect motivation derived from this approach should prove important in pest control across the world.

  9. Forecasting Renewable Energy Consumption under Zero Assumptions

    Directory of Open Access Journals (Sweden)

    Jie Ma

    2018-02-01

    Full Text Available Renewable energy, as an environmentally friendly and sustainable source of energy, is key to realizing the nationally determined contributions of the United States (US to the December 2015 Paris agreement. Policymakers in the US rely on energy forecasts to draft and implement cost-minimizing, efficient and realistic renewable and sustainable energy policies but the inaccuracies in past projections are considerably high. The inaccuracies and inconsistencies in forecasts are due to the numerous factors considered, massive assumptions and modeling flaws in the underlying model. Here, we propose and apply a machine learning forecasting algorithm devoid of massive independent variables and assumptions to model and forecast renewable energy consumption (REC in the US. We employ the forecasting technique to make projections on REC from biomass (REC-BMs and hydroelectric (HE-EC sources for the 2009–2016 period. We find that, relative to reference case projections in Energy Information Administration’s Annual Energy Outlook 2008, projections based on our proposed technique present an enormous improvement up to ~138.26-fold on REC-BMs and ~24.67-fold on HE-EC; and that applying our technique saves the US ~2692.62PJ petajoules(PJ on HE-EC and ~9695.09PJ on REC-BMs for the 8-year forecast period. The achieved high-accuracy is also replicable to other regions.

  10. An unbiased adaptive sampling algorithm for the exploration of RNA mutational landscapes under evolutionary pressure.

    Science.gov (United States)

    Waldispühl, Jérôme; Ponty, Yann

    2011-11-01

    The analysis of the relationship between sequences and structures (i.e., how mutations affect structures and reciprocally how structures influence mutations) is essential to decipher the principles driving molecular evolution, to infer the origins of genetic diseases, and to develop bioengineering applications such as the design of artificial molecules. Because their structures can be predicted from the sequence data only, RNA molecules provide a good framework to study this sequence-structure relationship. We recently introduced a suite of algorithms called RNAmutants which allows a complete exploration of RNA sequence-structure maps in polynomial time and space. Formally, RNAmutants takes an input sequence (or seed) to compute the Boltzmann-weighted ensembles of mutants with exactly k mutations, and sample mutations from these ensembles. However, this approach suffers from major limitations. Indeed, since the Boltzmann probabilities of the mutations depend of the free energy of the structures, RNAmutants has difficulties to sample mutant sequences with low G+C-contents. In this article, we introduce an unbiased adaptive sampling algorithm that enables RNAmutants to sample regions of the mutational landscape poorly covered by classical algorithms. We applied these methods to sample mutations with low G+C-contents. These adaptive sampling techniques can be easily adapted to explore other regions of the sequence and structural landscapes which are difficult to sample. Importantly, these algorithms come at a minimal computational cost. We demonstrate the insights offered by these techniques on studies of complete RNA sequence structures maps of sizes up to 40 nucleotides. Our results indicate that the G+C-content has a strong influence on the size and shape of the evolutionary accessible sequence and structural spaces. In particular, we show that low G+C-contents favor the apparition of internal loops and thus possibly the synthesis of tertiary structure motifs. On

  11. Time Series Analysis of Energy Production and Associated Landscape Fragmentation in the Eagle Ford Shale Play.

    Science.gov (United States)

    Pierre, Jon Paul; Young, Michael H; Wolaver, Brad D; Andrews, John R; Breton, Caroline L

    2017-11-01

    Spatio-temporal trends in infrastructure footprints, energy production, and landscape alteration were assessed for the Eagle Ford Shale of Texas. The period of analysis was over four 2-year periods (2006-2014). Analyses used high-resolution imagery, as well as pipeline data to map EF infrastructure. Landscape conditions from 2006 were used as baseline. Results indicate that infrastructure footprints varied from 94.5 km 2 in 2008 to 225.0 km 2 in 2014. By 2014, decreased land-use intensities (ratio of land alteration to energy production) were noted play-wide. Core-area alteration by period was highest (3331.6 km 2 ) in 2008 at the onset of play development, and increased from 582.3 to 3913.9 km 2 by 2014, though substantial revegetation of localized core areas was observed throughout the study (i.e., alteration improved in some areas and worsened in others). Land-use intensity in the eastern portion of the play was consistently lower than that in the western portion, while core alteration remained relatively constant east to west. Land alteration from pipeline construction was ~65 km 2 for all time periods, except in 2010 when alteration was recorded at 47 km 2 . Percent of total alteration from well-pad construction increased from 27.3% in 2008 to 71.5% in 2014. The average number of wells per pad across all 27 counties increased from 1.15 to 1.7. This study presents a framework for mapping landscape alteration from oil and gas infrastructure development. However, the framework could be applied to other energy development programs, such as wind or solar fields, or any other regional infrastructure development program. Landscape alteration caused by hydrocarbon pipeline installation in Val Verde County, Texas.

  12. Quantum coherence enabled determination of the energy landscape in light-harvesting complex II.

    Science.gov (United States)

    Calhoun, Tessa R; Ginsberg, Naomi S; Schlau-Cohen, Gabriela S; Cheng, Yuan-Chung; Ballottari, Matteo; Bassi, Roberto; Fleming, Graham R

    2009-12-24

    The near-unity efficiency of energy transfer in photosynthesis makes photosynthetic light-harvesting complexes a promising avenue for developing new renewable energy technologies. Knowledge of the energy landscape of these complexes is essential in understanding their function, but its experimental determination has proven elusive. Here, the observation of quantum coherence using two-dimensional electronic spectroscopy is employed to directly measure the 14 lowest electronic energy levels in light-harvesting complex II (LHCII), the most abundant antenna complex in plants containing approximately 50% of the world's chlorophyll. We observe that the electronically excited states are relatively evenly distributed, highlighting an important design principle of photosynthetic complexes that explains the observed ultrafast intracomplex energy transfer in LHCII.

  13. Underlying Event Studies for LHC Energies

    International Nuclear Information System (INIS)

    Barnafoeldi, Gergely Gabor; Levai, Peter; Agocs, Andras G.

    2011-01-01

    Underlying event was originally defined by the CDF collaboration decades ago. Here we improve the original definition to extend our analysis for events with multiple-jets. We introduce a definition for surrounding rings/belts and based on this definition the jet- and surrounding-belt-excluded areas will provide a good underlying event definition. We inverstigate our definition via the multiplicity in the defined geometry. In parallel, mean transverse momenta of these areas also studied in proton-proton collisions at √(s) = 7 TeV LHC energy.

  14. Free energy landscape and transition pathways from Watson-Crick to Hoogsteen base pairing in free duplex DNA.

    Science.gov (United States)

    Yang, Changwon; Kim, Eunae; Pak, Youngshang

    2015-09-18

    Houghton (HG) base pairing plays a central role in the DNA binding of proteins and small ligands. Probing detailed transition mechanism from Watson-Crick (WC) to HG base pair (bp) formation in duplex DNAs is of fundamental importance in terms of revealing intrinsic functions of double helical DNAs beyond their sequence determined functions. We investigated a free energy landscape of a free B-DNA with an adenosine-thymine (A-T) rich sequence to probe its conformational transition pathways from WC to HG base pairing. The free energy landscape was computed with a state-of-art two-dimensional umbrella molecular dynamics simulation at the all-atom level. The present simulation showed that in an isolated duplex DNA, the spontaneous transition from WC to HG bp takes place via multiple pathways. Notably, base flipping into the major and minor grooves was found to play an important role in forming these multiple transition pathways. This finding suggests that naked B-DNA under normal conditions has an inherent ability to form HG bps via spontaneous base opening events. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  15. Scales of Disconnection: Mismatches Shaping the Geographies of Emerging Energy Landscapes

    Directory of Open Access Journals (Sweden)

    Warren Charles R.

    2014-07-01

    Full Text Available The networked nature of energy systems produces geographies of connection, but the focus of this paper is on geographies of disconnection, exploring the multi-scalar processes which shape the context in which energy landscapes emerge. It does so, first, by presenting a case study of farmers' attitudes to perennial energy crops in south-west Scotland. Their strong antipathy to converting farmland to short-rotation coppice, and the reasons for their negative attitudes, exemplify some of the wider mismatches and disconnects which the paper goes on to discuss. These include socio-political and socio-cultural mismatches, and a range of essentially geographical disconnects which are scalar in nature, such as the familiar local-global tension and the mismatch between the scales (both temporal and spatial at which environmental and human systems organise and function. The discussion shows how these disjunctions not only affect energy geographies but also raise far-reaching questions about the ability of current governance structures and liberal democratic systems to respond swiftly and effectively to global challenges. The way that these mismatches are negotiated will mould both the character of future energy landscapes and the speed at which they take shape.

  16. Simple solvable energy-landscape model that shows a thermodynamic phase transition and a glass transition.

    Science.gov (United States)

    Naumis, Gerardo G

    2012-06-01

    When a liquid melt is cooled, a glass or phase transition can be obtained depending on the cooling rate. Yet, this behavior has not been clearly captured in energy-landscape models. Here, a model is provided in which two key ingredients are considered in the landscape, metastable states and their multiplicity. Metastable states are considered as in two level system models. However, their multiplicity and topology allows a phase transition in the thermodynamic limit for slow cooling, while a transition to the glass is obtained for fast cooling. By solving the corresponding master equation, the minimal speed of cooling required to produce the glass is obtained as a function of the distribution of metastable states.

  17. Free energy landscapes of electron transfer system in dipolar environment below and above the rotational freezing temperature

    International Nuclear Information System (INIS)

    Suzuki, Yohichi; Tanimura, Yoshitaka

    2007-01-01

    Electron transfer reaction in a polar solvent is modeled by a solute dipole surrounded by dipolar molecules with simple rotational dynamics posted on the three-dimensional distorted lattice sites. The interaction energy between the solute and solvent dipoles as a reaction coordinate is adopted and free energy landscapes are calculated by generating all possible states for a 26 dipolar system and by employing Wang-Landau sampling algorithm for a 92 dipolar system. For temperatures higher than the energy scale of dipole-dipole interactions, the free energy landscapes for the small reaction coordinate region have quadratic shape as predicted by Marcus [Rev. Mod. Phys. 65, 599 (1993)] whereas for the large reaction coordinate region, the landscapes exhibit a nonquadratic shape. When the temperature drops, small notched structures appear on the free energy profiles because of the frustrated interactions among dipoles. The formation of notched structure is analyzed with statistical approach and it is shown that the amplitude of notched structure depend upon the segment size of the reaction coordinate and is characterized by the interaction energy among the dipoles. Using simulated free energy landscapes, the authors calculate the reaction rates as a function of the energy gap for various temperatures. At high temperature, the reactions rates follow a bell shaped (inverted parabolic) energy gap law in the small energy gap regions, while it becomes steeper than the parabolic shape in a large energy gap regions due to the nonquadratic shape of the free energy landscape. The peak position of parabola also changes as the function of temperature. At low temperature, the profile of the reaction rates is no longer smooth because of the many local minima of the free energy landscape

  18. Evidence and opportunities for integrating landscape ecology into natural resource planning across multiple-use landscapes

    Science.gov (United States)

    Trammel, E. Jamie; Carter, Sarah; Haby, Travis S.; Taylor, Jason J.

    2018-01-01

    Enhancing natural resource management has been a focus of landscape ecology since its inception, but numerous authors argue that landscape ecology has not yet been effective in achieving the underlying goal of planning and designing sustainable landscapes. We developed nine questions reflecting the application of fundamental research topics in landscape ecology to the landscape planning process and reviewed two recent landscape-scale plans in western North America for evidence of these concepts in plan decisions. Both plans considered multiple resources, uses, and values, including energy development, recreation, conservation, and protection of cultural and historic resources. We found that land use change and multiscale perspectives of resource uses and values were very often apparent in planning decisions. Pattern-process relationships, connectivity and fragmentation, ecosystem services, landscape history, and climate change were reflected less frequently. Landscape sustainability was considered only once in the 295 decisions reviewed, and outputs of landscape models were not referenced. We suggest six actionable opportunities for further integrating landscape ecology concepts into landscape planning efforts: 1) use landscape sustainability as an overarching goal, 2) adopt a broad ecosystem services framework, 3) explore the role of landscape history more comprehensively, 4) regularly consider and accommodate potential effects of climate change, 5) use landscape models to support plan decisions, and 6) promote a greater presence of landscape ecologists within agencies that manage large land bases and encourage active involvement in agency planning efforts. Together these actions may improve the defensibility, durability, and sustainability of landscape plan decisions.

  19. Rethinking Sustainability within the Viticulture Realities Integrating Economy, Landscape and Energy

    Directory of Open Access Journals (Sweden)

    Ilaria Zambon

    2018-01-01

    Full Text Available Sustainability is often explained through three dimensions (society, economy and environment. However, such a definition currently appears to be restricted. Sustainable development often includes the energy issue. An example of realities founded on bioenergy are agro-energy districts. These realities involve all the three dimensions of sustainability, integrating also the energy dimension and fueling a potential circular economy. Based on these premises, the most affluent rural subdivision in Italy is that of wine. The wine sector has experienced a recent growth of its economic market, diverging from other agricultural activities and enlarging its cultivated surface areas. In this sense, the local landscape has also changed. Owing to the strong inclination of the wine sector in adopting sustainable strategies and measures, agro-energy districts can be the following future phase in viticulture realities as a cutting-edge business in the modern agricultural sector, implementing new strategies and opportunities.

  20. The collective diffusion coefficient as a shape detector of the surface energy landscape

    Science.gov (United States)

    Mińkowski, Marcin; Załuska–Kotur, Magdalena A.

    2018-01-01

    The general expression for the diffusion coefficient for a dense, interacting particle system moving through a one-dimensional non-homogeneous energy potential is derived. Based on this expression, it is shown that the diffusion coefficient as a function of density depends to a great extent on the shape of the energy landscape. The presence of other particles affects the diffusion coefficient in another way as they pass through the same energy barriers, but set in a different order. The obtained result comes from a variational approach to diffusion and the interactions are taken into account using the transfer-matrix method. Interactions impact on the dynamics of the system, both by changing the equilibrium probabilities of the occupied states and by changing the barriers for the particle jumps. Several examples of diffusion in different energy potentials are presented and the dependence of the diffusion coefficient on potential and interactions is discussed.

  1. Comparison of Recent Oil and Gas, Wind Energy, and Other Anthropogenic Landscape Alteration Factors in Texas Through 2014.

    Science.gov (United States)

    Pierre, Jon Paul; Wolaver, Brad D; Labay, Benjamin J; LaDuc, Travis J; Duran, Charles M; Ryberg, Wade A; Hibbitts, Toby J; Andrews, John R

    2018-05-01

    Recent research assessed how hydrocarbon and wind energy expansion has altered the North American landscape. Less understood, however, is how this energy development compares to other anthropogenic land use changes. Texas leads U.S. hydrocarbon production and wind power generation and has a rapidly expanding population. Thus, for ~47% of Texas (~324,000 km 2 ), we mapped the 2014 footprint of energy activities (~665,000 oil and gas wells, ~5700 wind turbines, ~237,000 km oil and gas pipelines, and ~2000 km electrical transmission lines). We compared the footprint of energy development to non-energy-related activities (agriculture, roads, urbanization) and found direct landscape alteration from all factors affects ~23% of the study area (~76,000 km 2 ), led by agriculture (~16%; ~52,882 km 2 ). Oil and gas activities altered energy occupied energy infrastructure caused more indirect landscape alteration than larger, more concentrated urbanization and agriculture. This study presents a novel technique to quantify and compare anthropogenic activities causing both direct and indirect landscape alteration. We illustrate this landscape-mapping framework in Texas for the Spot-tailed Earless Lizard (Holbrookia lacerata); however, the approach can be applied to a range of species in developing regions globally.

  2. Time Series Analysis of Energy Production and Associated Landscape Fragmentation in the Eagle Ford Shale Play

    Science.gov (United States)

    Pierre, Jon Paul; Young, Michael H.; Wolaver, Brad D.; Andrews, John R.; Breton, Caroline L.

    2017-11-01

    Spatio-temporal trends in infrastructure footprints, energy production, and landscape alteration were assessed for the Eagle Ford Shale of Texas. The period of analysis was over four 2-year periods (2006-2014). Analyses used high-resolution imagery, as well as pipeline data to map EF infrastructure. Landscape conditions from 2006 were used as baseline. Results indicate that infrastructure footprints varied from 94.5 km2 in 2008 to 225.0 km2 in 2014. By 2014, decreased land-use intensities (ratio of land alteration to energy production) were noted play-wide. Core-area alteration by period was highest (3331.6 km2) in 2008 at the onset of play development, and increased from 582.3 to 3913.9 km2 by 2014, though substantial revegetation of localized core areas was observed throughout the study (i.e., alteration improved in some areas and worsened in others). Land-use intensity in the eastern portion of the play was consistently lower than that in the western portion, while core alteration remained relatively constant east to west. Land alteration from pipeline construction was 65 km2 for all time periods, except in 2010 when alteration was recorded at 47 km2. Percent of total alteration from well-pad construction increased from 27.3% in 2008 to 71.5% in 2014. The average number of wells per pad across all 27 counties increased from 1.15 to 1.7. This study presents a framework for mapping landscape alteration from oil and gas infrastructure development. However, the framework could be applied to other energy development programs, such as wind or solar fields, or any other regional infrastructure development program.

  3. Electrostatics, structure prediction, and the energy landscapes for protein folding and binding.

    Science.gov (United States)

    Tsai, Min-Yeh; Zheng, Weihua; Balamurugan, D; Schafer, Nicholas P; Kim, Bobby L; Cheung, Margaret S; Wolynes, Peter G

    2016-01-01

    While being long in range and therefore weakly specific, electrostatic interactions are able to modulate the stability and folding landscapes of some proteins. The relevance of electrostatic forces for steering the docking of proteins to each other is widely acknowledged, however, the role of electrostatics in establishing specifically funneled landscapes and their relevance for protein structure prediction are still not clear. By introducing Debye-Hückel potentials that mimic long-range electrostatic forces into the Associative memory, Water mediated, Structure, and Energy Model (AWSEM), a transferable protein model capable of predicting tertiary structures, we assess the effects of electrostatics on the landscapes of thirteen monomeric proteins and four dimers. For the monomers, we find that adding electrostatic interactions does not improve structure prediction. Simulations of ribosomal protein S6 show, however, that folding stability depends monotonically on electrostatic strength. The trend in predicted melting temperatures of the S6 variants agrees with experimental observations. Electrostatic effects can play a range of roles in binding. The binding of the protein complex KIX-pKID is largely assisted by electrostatic interactions, which provide direct charge-charge stabilization of the native state and contribute to the funneling of the binding landscape. In contrast, for several other proteins, including the DNA-binding protein FIS, electrostatics causes frustration in the DNA-binding region, which favors its binding with DNA but not with its protein partner. This study highlights the importance of long-range electrostatics in functional responses to problems where proteins interact with their charged partners, such as DNA, RNA, as well as membranes. © 2015 The Protein Society.

  4. Ageing first passage time density in continuous time random walks and quenched energy landscapes

    Science.gov (United States)

    Krüsemann, Henning; Godec, Aljaž; Metzler, Ralf

    2015-07-01

    We study the first passage dynamics of an ageing stochastic process in the continuous time random walk (CTRW) framework. In such CTRW processes the test particle performs a random walk, in which successive steps are separated by random waiting times distributed in terms of the waiting time probability density function \\psi (t)≃ {t}-1-α (0≤slant α ≤slant 2). An ageing stochastic process is defined by the explicit dependence of its dynamic quantities on the ageing time ta, the time elapsed between its preparation and the start of the observation. Subdiffusive ageing CTRWs with 0\\lt α \\lt 1 describe systems such as charge carriers in amorphous semiconducters, tracer dispersion in geological and biological systems, or the dynamics of blinking quantum dots. We derive the exact forms of the first passage time density for an ageing subdiffusive CTRW in the semi-infinite, confined, and biased case, finding different scaling regimes for weakly, intermediately, and strongly aged systems: these regimes, with different scaling laws, are also found when the scaling exponent is in the range 1\\lt α \\lt 2, for sufficiently long ta. We compare our results with the ageing motion of a test particle in a quenched energy landscape. We test our theoretical results in the quenched landscape against simulations: only when the bias is strong enough, the correlations from returning to previously visited sites become insignificant and the results approach the ageing CTRW results. With small bias or without bias, the ageing effects disappear and a change in the exponent compared to the case of a completely annealed landscape can be found, reflecting the build-up of correlations in the quenched landscape.

  5. Quantitative analysis of the publishing landscape in high-energy physics

    International Nuclear Information System (INIS)

    Mele, Salvatore; Dallman, David; Vigen, Jens; Yeomans, Joanne

    2006-01-01

    World-wide collaboration in high-energy physics (HEP) is a tradition which dates back several decades, with scientific publications mostly coauthored by scientists from different countries. This coauthorship phenomenon makes it difficult to identify precisely the 'share' of each country in HEP scientific production. One year's worth of HEP scientific articles published in peer-reviewed journals is analysed and their authors are uniquely assigned to countries. This method allows the first correct estimation on a pro rata basis of the share of HEP scientific publishing among several countries and institutions. The results provide an interesting insight into the geographical collaborative patterns of the HEP community. The HEP publishing landscape is further analysed to provide information on the journals favoured by the HEP community and on the geographical variation of their author bases. These results provide quantitative input to the ongoing debate on the possible transition of HEP publishing to an Open Access model. Foreword. This paper reports the results of a recent detailed study of the publishing landscape in high energy physics. We thought that because of its direct relevance to the high energy physics community, this important quantitative input to the debate on the transition to Open Access naturally finds its place in our journal. Marc Henneaux, JHEP Scientific Director

  6. Free energy landscape and cooperatively rearranging region in a hard sphere glass

    Science.gov (United States)

    Yoshidome, Takashi; Yoshimori, Akira; Odagaki, Takashi

    2007-08-01

    Exploiting the density functional theory, we calculate the free energy landscape (FEL) of the hard sphere glass in three dimensions. From the FEL, we estimate the number of the particles in the cooperatively rearranging region (CRR). We find that the density dependence of the number of the particles in the CRR is expressed as a power law function of the density. Analyzing the relaxation process in the CRR, we also find that the string motion is the elementary process for the structural relaxation, which leads to the natural definition of the simultaneously rearranging region as the particles displaced in the string motion.

  7. Obsolete or resurgent? The International Energy Agency in a changing global landscape

    International Nuclear Information System (INIS)

    Van de Graaf, Thijs

    2012-01-01

    Founded in response to the 1973 oil shock, the International Energy Agency (IEA) is arguably still the most important multilateral organization for energy-importing countries. Yet, the global geopolitical landscape has changed considerably since the IEA's creation. The rise of new energy consumers, new energy-related challenges and new international energy forums prompt a rethink of the agency's current role and institutional design. This article seeks to contribute to the recent debate on the future role of the IEA by examining specific drivers, avenues and constraints for institutional reform. The method used is SWOT analysis, which allows to summarize the key factors emanating from an assessment of an organization's internal characteristics (strengths and weaknesses) and its external environment (opportunities and threats). Building on this SWOT analysis, the article formulates a strategy for the IEA to remain the focal point in global energy governance. Key elements of this strategy include: stronger engagement with new consumers, rapprochement with OPEC, becoming a leading voice in the energy transition, and changing the agency's internal governance practices. - Highlights: ► The IEA is challenged by the rise of new consumers, threats and organizations. ► Assessment of the agency’s internal characteristics and external environment. ► The IEA needs to step up its outreach policy and fully embrace sustainable energy.

  8. Power-law distributions for the areas of the basins of attraction on a potential energy landscape.

    Science.gov (United States)

    Massen, Claire P; Doye, Jonathan P K

    2007-03-01

    Energy landscape approaches have become increasingly popular for analyzing a wide variety of chemical physics phenomena. Basic to many of these applications has been the inherent structure mapping, which divides up the potential energy landscape into basins of attraction surrounding the minima. Here, we probe the nature of this division by introducing a method to compute the basin area distribution and applying it to some archetypal supercooled liquids. We find that this probability distribution is a power law over a large number of decades with the lower-energy minima having larger basins of attraction. Interestingly, the exponent for this power law is approximately the same as that for a high-dimensional Apollonian packing, providing further support for the suggestion that there is a strong analogy between the way the energy landscape is divided into basins, and the way that space is packed in self-similar, space-filling hypersphere packings, such as the Apollonian packing. These results suggest that the basins of attraction provide a fractal-like tiling of the energy landscape, and that a scale-free pattern of connections between the minima is a general property of energy landscapes.

  9. A deterministic method for estimating free energy genetic network landscapes with applications to cell commitment and reprogramming paths.

    Science.gov (United States)

    Olariu, Victor; Manesso, Erica; Peterson, Carsten

    2017-06-01

    Depicting developmental processes as movements in free energy genetic landscapes is an illustrative tool. However, exploring such landscapes to obtain quantitative or even qualitative predictions is hampered by the lack of free energy functions corresponding to the biochemical Michaelis-Menten or Hill rate equations for the dynamics. Being armed with energy landscapes defined by a network and its interactions would open up the possibility of swiftly identifying cell states and computing optimal paths, including those of cell reprogramming, thereby avoiding exhaustive trial-and-error simulations with rate equations for different parameter sets. It turns out that sigmoidal rate equations do have approximate free energy associations. With this replacement of rate equations, we develop a deterministic method for estimating the free energy surfaces of systems of interacting genes at different noise levels or temperatures. Once such free energy landscape estimates have been established, we adapt a shortest path algorithm to determine optimal routes in the landscapes. We explore the method on three circuits for haematopoiesis and embryonic stem cell development for commitment and reprogramming scenarios and illustrate how the method can be used to determine sequential steps for onsets of external factors, essential for efficient reprogramming.

  10. Optimal dimensionality reduction of complex dynamics: The chess game as diffusion on a free-energy landscape

    Science.gov (United States)

    Krivov, Sergei V.

    2011-07-01

    Dimensionality reduction is ubiquitous in the analysis of complex dynamics. The conventional dimensionality reduction techniques, however, focus on reproducing the underlying configuration space, rather than the dynamics itself. The constructed low-dimensional space does not provide a complete and accurate description of the dynamics. Here I describe how to perform dimensionality reduction while preserving the essential properties of the dynamics. The approach is illustrated by analyzing the chess game—the archetype of complex dynamics. A variable that provides complete and accurate description of chess dynamics is constructed. The winning probability is predicted by describing the game as a random walk on the free-energy landscape associated with the variable. The approach suggests a possible way of obtaining a simple yet accurate description of many important complex phenomena. The analysis of the chess game shows that the approach can quantitatively describe the dynamics of processes where human decision-making plays a central role, e.g., financial and social dynamics.

  11. A Tale of Two Regions: Landscape Ecological Planning for Shale Gas Energy Futures

    Science.gov (United States)

    Murtha, T., Jr.; Schroth, O.; Orland, B.; Goldberg, L.; Mazurczyk, T.

    2015-12-01

    As we increasingly embrace deep shale gas deposits to meet global energy demands new and dispersed local and regional policy and planning challenges emerge. Even in regions with long histories of energy extraction, such as coal, shale gas and the infrastructure needed to produce the gas and transport it to market offers uniquely complex transformations in land use and landcover not previously experienced. These transformations are fast paced, dispersed and can overwhelm local and regional planning and regulatory processes. Coupled to these transformations is a structural confounding factor. While extraction and testing are carried out locally, regulation and decision-making is multilayered, often influenced by national and international factors. Using a geodesign framework, this paper applies a set of geospatial landscape ecological planning tools in two shale gas settings. First, we describe and detail a series of ongoing studies and tools that we have developed for communities in the Marcellus Shale region of the eastern United States, specifically the northern tier of Pennsylvania. Second, we apply a subset of these tools to potential gas development areas of the Fylde region in Lancashire, United Kingdom. For the past five years we have tested, applied and refined a set of place based and data driven geospatial models for forecasting, envisioning, analyzing and evaluating shale gas activities in northern Pennsylvania. These models are continuously compared to important landscape ecological planning challenges and priorities in the region, e.g. visual and cultural resource preservation. Adapting and applying these tools to a different landscape allow us to not only isolate and define important regulatory and policy exigencies in each specific setting, but also to develop and refine these models for broader application. As we continue to explore increasingly complex energy solutions globally, we need an equally complex comparative set of landscape ecological

  12. Evolution of the potential energy landscape with static pulling force for two model proteins.

    Science.gov (United States)

    Wales, David J; Head-Gordon, Teresa

    2012-07-26

    The energy landscape is analyzed for off-lattice bead models of protein L and protein G as a function of a static pulling force. Two different pairs of attachment points (pulling directions) are compared in each case, namely, residues 1/56 and 10/32. For the terminal residue pulling direction 1/56, the distinct global minimum structures are all extended, aside from the compact geometry that correlates with zero force. The helical turns finally disappear at the highest pulling forces considered. For the 10/32 pulling direction, the changes are more complicated, with a variety of competing arrangements for beads outside the region where the force is directly applied. These alternatives produce frustrated energy landscapes, with low-lying minima separated by high barriers. The calculated folding pathways in the absence of force are in good agreement with previous work. The N-terminal hairpin folds first for protein L and the C-terminal hairpin for protein G, which exhibits an intermediate. However, for a relatively low static force, where the global minimum retains its structure, the folding mechanisms change, sometimes dramatically, depending on the protein and the attachment points. The scaling relations predicted by catastrophe theory are found to hold in the limit of short path lengths.

  13. Low-dimensional, free-energy landscapes of protein-folding reactions by nonlinear dimensionality reduction

    Science.gov (United States)

    Das, Payel; Moll, Mark; Stamati, Hernán; Kavraki, Lydia E.; Clementi, Cecilia

    2006-06-01

    The definition of reaction coordinates for the characterization of a protein-folding reaction has long been a controversial issue, even for the "simple" case in which one single free-energy barrier separates the folded and unfolded ensemble. We propose a general approach to this problem to obtain a few collective coordinates by using nonlinear dimensionality reduction. We validate the usefulness of this method by characterizing the folding landscape associated with a coarse-grained protein model of src homology 3 as sampled by molecular dynamics simulations. The folding free-energy landscape projected on the few relevant coordinates emerging from the dimensionality reduction can correctly identify the transition-state ensemble of the reaction. The first embedding dimension efficiently captures the evolution of the folding process along the main folding route. These results clearly show that the proposed method can efficiently find a low-dimensional representation of a complex process such as protein folding. reaction coordinate | transition state | manifold | embedding | ISOMAP

  14. Theoretical investigation of new magnetic recording media using an energy landscape method

    Science.gov (United States)

    Zhu, Ru

    Magnetic material has played an important role in the information storage technology. We have worked out a phase diagram showing spin torque switching for perpendicular anisotropy media at nonzero temperature. A new area is predicted where the system can vibrate between precessional and parallel states quickly and therefore creates "telegraph" noise region. The result was later confirmed by a nanopillar experiment. The density of magnetic recording is restricted by the superparamagnetic limit. To overcome this limit people have used perpendicular recording to replace the traditional longitudinal recording and are working on other approaches to get over the superparamagnetic limit including heat assisted recording, patterned media and exchange coupled media. Anisotropy graded media provides an alternative solution to achieve high areal density while keeping the writing field relatively low and good thermal stability. A two-dimensional energy landscape of the switching of anisotropy graded media is calculated to give an intuitive way of understanding the switching, as well as a way to quantitatively calculate the switching rate by mapping the problem onto a one-dimensional Langevin random walk. Then an iterative algorithm of for finding the saddle point of the energy landscape, which we call barbell algorithm, is used to locate the saddle point and the whole switching trajectory.

  15. The renewable energies: the landscape; Les energies renouvelables: un tour d'horizon

    Energy Technology Data Exchange (ETDEWEB)

    Acket, C.; Bacher, P

    2005-03-15

    If one takes into account the hydroelectric power, the France is the first european country in the renewable energies domain. The position is also honorable concerning the wood energy. Meanwhile, for the solar and wind energy, France is late. To discuss this debate, the authors bring together today data on the renewable energies, offer some proposals for the next 50 years taking into account the reduction of greenhouse gases emission for 2050. (A.L.B.)

  16. Co-designing energy landscapes: Application of participatory mapping and geographic information systems in the exploration of low carbon futures

    NARCIS (Netherlands)

    Stremke, S.; Picchi, Paolo

    2017-01-01

    The chapter begins with a literature review of energy potential mapping, ecosystem services (ES) assessment and participatory mapping (PM). PM is a key technique to conduct tradeoff analysis while co-designing sustainable energy landscapes (SEL) with local communities. Stakeholders, among others,

  17. Diffusion of irreversible energy technologies under uncertainty

    Energy Technology Data Exchange (ETDEWEB)

    Cacallo, J.D.; Sutherland, R.J.

    1993-09-01

    This paper presents a model of technology diffusion is consistent with characteristics of participants in most energy markets. Whereas the models used most widely for empirical research are based on the assumption that the extended delays in adoption of cost-saving innovations are the result of either lack of knowledge about the new processes or heterogeneity across potential adopters, the model presented in this paper is based on the strategic behavior by firms. The strategic interdependence of the firms` decisions is rooted in spillover effects associated with an inability to exclude others from the learning-by-doing acquired when a firm implements a new technology. The model makes extensive use of recent developments in investment theory as it relates irreversible investments under uncertainty.

  18. Following Gibbs states adiabatically: the energy landscape of mean field glassy systems

    Energy Technology Data Exchange (ETDEWEB)

    Zdeborova, Lenka [Los Alamos National Laboratory; Krzakala, Florent [ESPCI

    2009-01-01

    We introduce a generalization of the cavity, or Bethe-Peierls, method that allows to follow Gibbs states when an external parameter, e.g. the temperature, is adiabatically changed. This allows to obtain new quantitative results on the static and dynamic behavior of mean field disordered systems such as models of glassy and amorphous materials or random constraint satisfaction problems. As a first application, we discuss the residual energy after a very slow annealing, the behavior of out-of-equilibrium states, and demonstrate the presence of temperature chaos in equilibrium. We also explore the energy landscape, and identify a new transition from an computationally easier canyons-dominated region to a harder valleys-dominated one.

  19. Isomers and energy landscapes of micro-hydrated sulfite and chlorate clusters

    Science.gov (United States)

    Hey, John C.; Doyle, Emily J.; Chen, Yuting; Johnston, Roy L.

    2018-03-01

    We present putative global minima for the micro-hydrated sulfite SO32-(H2O)N and chlorate ClO32(H2O)N systems in the range 3≤N≤15 found using basin-hopping global structure optimization with an empirical potential. We present a structural analysis of the hydration of a large number of minimized structures for hydrated sulfite and chlorate clusters in the range 3≤N≤50. We show that sulfite is a significantly stronger net acceptor of hydrogen bonding within water clusters than chlorate, completely suppressing the appearance of hydroxyl groups pointing out from the cluster surface (dangling OH bonds), in low-energy clusters. We also present a qualitative analysis of a highly explored energy landscape in the region of the global minimum of the eight water hydrated sulfite and chlorate systems. This article is part of the theme issue `Modern theoretical chemistry'.

  20. Isomers and energy landscapes of micro-hydrated sulfite and chlorate clusters.

    Science.gov (United States)

    Hey, John C; Doyle, Emily J; Chen, Yuting; Johnston, Roy L

    2018-03-13

    We present putative global minima for the micro-hydrated sulfite SO 3 2- (H 2 O) N and chlorate ClO 3 - (H 2 O) N systems in the range 3≤ N ≤15 found using basin-hopping global structure optimization with an empirical potential. We present a structural analysis of the hydration of a large number of minimized structures for hydrated sulfite and chlorate clusters in the range 3≤ N ≤50. We show that sulfite is a significantly stronger net acceptor of hydrogen bonding within water clusters than chlorate, completely suppressing the appearance of hydroxyl groups pointing out from the cluster surface (dangling OH bonds), in low-energy clusters. We also present a qualitative analysis of a highly explored energy landscape in the region of the global minimum of the eight water hydrated sulfite and chlorate systems.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Authors.

  1. Model forest landscape change in the Missouri Ozarks under alternative management practices

    Science.gov (United States)

    Stephen R. Shifley; Frank R. Thompson; David R. Larsen; William D. Dijak

    2000-01-01

    We used a spatially explicit landscape model, LANDIS, to simulate the effects of five management alternatives on a 3216 ha forest landscape in southeast Missouri, USA. We compared management alternatives among two intensities of even-aged management with clearcutting, uneven-aged management with group selection harvest, a mixture of even- and uneven-aged management,...

  2. Belowground Water Dynamics Under Contrasting Annual and Perennial Plant Communities in an Agriculturally-Dominated Landscape

    Science.gov (United States)

    Mora, G.; Asbjornsen, H.; Helmers, M. J.; Shepherd, G. W.

    2005-12-01

    The conversion from grasslands and forests to row-crops in the Midwest has affected soil water cycling because plant characteristics are one of the main parameters determining soil storage capacity, infiltration rates, and surface runoff. Little is known, however, about the extent of modification of soil water dynamics under different plant communities. To address this important issue, we are documenting soil water dynamics under contrasting perennial and annual plant communities in an agriculturally-dominated landscape. Measurements of soil moisture and depths of uptake of source water were obtained for six vegetative cover types (corn and soybean field, brome pasture, degraded savanna, restored savanna, and restored prairie) at the Neal Smith National Wildlife Refuge in Prairie City, Iowa. The depths of uptake of soil water were determined on the basis of oxygen isotope composition of soil water and stem water. Measurements were performed once a month during an entire growing season. Preliminary results indicate that soil water present under the different vegetation types show similar profiles with depth during the dry months. Soil water in the upper 5 cm is enriched in oxygen-18 by about 5 per mil relative to soil water at 100 cm. Our preliminary results also indicate that the isotopic composition of stem water from annual plants is typically higher by about 2 per mil relative to that of stem water from perennial plants during the dry period. Whereas the oxygen isotopic composition for corn stem water is -5.49 per mil, that for elm and oak stem water is -7.62 and -7.51 per mil, respectively. The higher isotope values for corn suggest that annual crop plants are withdrawing water from shallower soil horizons relative to perennial plants. Moreover, our preliminary data suggest lower moisture content in soil under annual plant cover. We propose that the presence of deeper roots in the perennial vegetation allows these plants to tap into deeper water sources when

  3. Characterization of the dynamics of glass-forming liquids from the properties of the potential energy landscape.

    Science.gov (United States)

    Banerjee, Sumilan; Dasgupta, Chandan

    2012-02-01

    We develop a framework for understanding the difference between strong and fragile behavior in the dynamics of glass-forming liquids from the properties of the potential energy landscape. Our approach is based on a master equation description of the activated jump dynamics among the local minima of the potential energy (the so-called inherent structures) that characterize the potential energy landscape of the system. We study the dynamics of a small atomic cluster using this description as well as molecular dynamics simulations and demonstrate the usefulness of our approach for this system. Many of the remarkable features of the complex dynamics of glassy systems emerge from the activated dynamics in the potential energy landscape of the atomic cluster. The dynamics of the system exhibits typical characteristics of a strong supercooled liquid when the system is allowed to explore the full configuration space. This behavior arises because the dynamics is dominated by a few lowest-lying minima of the potential energy and the potential energy barriers between these minima. When the system is constrained to explore only a limited region of the potential energy landscape that excludes the basins of attraction of a few lowest-lying minima, the dynamics is found to exhibit the characteristics of a fragile liquid. © 2012 American Physical Society

  4. Applying a framework for landscape planning under climate change for the conservation of biodiversity in the Finnish boreal forest

    DEFF Research Database (Denmark)

    Mazziotta, Adriano; Triviño, Maria; Tikkanen, Olli Pekka

    2015-01-01

    capacities. Although methods for defining vulnerability categories are available, methods for doing this in a systematic, cost-effective way have not been identified. Here, we use an ecosystem model to define the potential resilience of the Finnish forest landscape by relating its current conservation......Conservation strategies are often established without consideration of the impact of climate change. However, this impact is expected to threaten species and ecosystem persistence and to have dramatic effects towards the end of the 21st century. Landscape suitability for species under climate...... change is determined by several interacting factors including dispersal and human land use. Designing effective conservation strategies at regional scales to improve landscape suitability requires measuring the vulnerabilities of specific regions to climate change and determining their conservation...

  5. Landscape relatedness

    DEFF Research Database (Denmark)

    Norman, Anita J; Strønen, Astrid Vik; Fuglstad, Geir-Arne

    2017-01-01

    Context Methods for detecting contemporary, fine-scale population genetic structure in continuous populations are scarce. Yet such methods are vital for ecological and conservation studies, particularly under a changing landscape. Objectives Here we present a novel, spatially explicit method...... that we call landscape relatedness (LandRel). With this method, we aim to detect contemporary, fine-scale population structure that is sensitive to spatial and temporal changes in the landscape. Methods We interpolate spatially determined relatedness values based on SNP genotypes across the landscape...

  6. Impacts on the environment and landscape of new energy productions on farm parcels and buildings, Final report

    International Nuclear Information System (INIS)

    Pointereau, Ph.; Bochu, J.L.; Couturier, Ch.; Coulon, F.; Arnal, A.; Giorgis, S.

    2009-01-01

    This study aims at identifying positive and negative impacts of new energy productions implemented in farms on the environment (water, soil, biodiversity, space occupancy) and on landscapes, and at proposing techniques and regulations to strengthen positive consequences and to limit possible problems created by these energy productions. The considered productions are: trees apart from forest (hedges and copses), new farm energetic crops (Miscanthus for example), solar equipment (photovoltaic mounted on buildings or on ground, solar hot water and solar dryers), biogas production equipment, hydraulic micro-plants. The authors addressed the following environmental impacts: water (in quantity and quality), soils (quality, erosion risks), biodiversity, space occupancy (with respect to other activities), and landscape

  7. Applying a framework for landscape planning under climate change for the conservation of biodiversity in the Finnish boreal forest.

    Science.gov (United States)

    Mazziotta, Adriano; Triviño, Maria; Tikkanen, Olli-Pekka; Kouki, Jari; Strandman, Harri; Mönkkönen, Mikko

    2015-02-01

    Conservation strategies are often established without consideration of the impact of climate change. However, this impact is expected to threaten species and ecosystem persistence and to have dramatic effects towards the end of the 21st century. Landscape suitability for species under climate change is determined by several interacting factors including dispersal and human land use. Designing effective conservation strategies at regional scales to improve landscape suitability requires measuring the vulnerabilities of specific regions to climate change and determining their conservation capacities. Although methods for defining vulnerability categories are available, methods for doing this in a systematic, cost-effective way have not been identified. Here, we use an ecosystem model to define the potential resilience of the Finnish forest landscape by relating its current conservation capacity to its vulnerability to climate change. In applying this framework, we take into account the responses to climate change of a broad range of red-listed species with different niche requirements. This framework allowed us to identify four categories in which representation in the landscape varies among three IPCC emission scenarios (B1, low; A1B, intermediate; A2, high emissions): (i) susceptible (B1 = 24.7%, A1B = 26.4%, A2 = 26.2%), the most intact forest landscapes vulnerable to climate change, requiring management for heterogeneity and resilience; (ii) resilient (B1 = 2.2%, A1B = 0.5%, A2 = 0.6%), intact areas with low vulnerability that represent potential climate refugia and require conservation capacity maintenance; (iii) resistant (B1 = 6.7%, A1B = 0.8%, A2 = 1.1%), landscapes with low current conservation capacity and low vulnerability that are suitable for restoration projects; (iv) sensitive (B1 = 66.4%, A1B = 72.3%, A2 = 72.0%), low conservation capacity landscapes that are vulnerable and for which alternative conservation measures are required depending on the

  8. Control over Structure and Function of Peptide Amphiphile Supramolecular Assemblies through Molecular Design and Energy Landscapes

    Science.gov (United States)

    Tantakitti, Faifan

    Supramolecular chemistry is a powerful tool to create a material of a defined structure with tunable properties. This strategy has led to catalytically active, bioactive, and environment-responsive materials, among others, that are valuable in applications ranging from sensor technology to energy and medicine. Supramolecular polymers formed by peptide amphiphiles (PAs) have been especially relevant in tissue regeneration due to their ability to form biocompatible structures and mimic many important signaling molecules in biology. These supramolecular polymers can form nanofibers that create networks which mimic natural extracellular matrices. PA materials have been shown to induce growth of blood vessels, bone, cartilage, and nervous tissue, among others. The work described in this thesis not only studied the relationship between molecular structure and functions of PA assemblies, but also uncovered a powerful link between the energy landscape of their supramolecular self-assembly and the ability of PA materials to interact with cells. In chapter 2, it is argued that fabricating fibrous nanostructures with defined mechanical properties and decoration with bioactive molecules is not sufficient to create a material that can effectively communicate with cells. By systemically placing the fibronectin-derived RGDS epitope at increasing distances from the surface of PA nanofibers through a linker of one to five glycine residues, integrin-mediated RGDS signaling was enhanced. The results suggested that the spatial presentation of an epitope on PA nanofibers strongly influences the bioactivity of the PA substrates. In further improving functionality of a PA-based scaffold to effectively direct cell growth and differentiation, chapter 3 explored the use of a cell microcarrier to compartmentalize and simultaneously tune insoluble and soluble signals in a single matrix. PA nanofibers were incorporated at the surface of the microcarrier in order to promote cell adhesion, while

  9. A Community Landscape Model of Pro-Environmental Behavior: The Effects of Landscape and Community Interaction on Residential Energy Behaviors in Two Pennsylvania Towns

    Science.gov (United States)

    Mainzer, Stephen P.

    We are using more energy every year. Between 2001 and 2011, Pennsylvania residential electricity sales increased by two and a half times the number of new customers, accounting for almost one third of the state's total electricity consumption. Our ability to meet demand by acquiring new energy sources faces several challenges. Confusion surrounds the physical and economic accessibility of remaining fossil fuel sources. Immense land use requirements and subsequent environmental impacts challenge a total shift to renewable energy sources. The laws of thermodynamics limit the potential for new technology to efficiently convert raw energy to consumable sources. As a result, any rational strategy to meet future energy demands must involve conservation. Conservation is a pro-environmental behavior, an act intended to benefit the environment surrounding a person. I posit that a transdisciplinary model, the community landscape model of the pro-environmental behavior, unifies the conceptually analogous - yet disparate - fields of landscape, community, and behavior towards explaining residential energy conservation actions. Specifically, the study attempted to describe links between the physical environment, social environment, and conservation behaviors through a mixed-method framework. Two Pennsylvania townships - Spring and East Buffalo townships - were selected from an analysis of housing, electricity consumption, and land cover trends. Key informants from both townships informed the design of a survey instrument that captured the utility consumption, residential conservation actions, energy and environmental values, types and levels of community engagement, perceived barriers, and socio-demographic information from 107 randomly selected households. A mixed-method analysis produced evidence that place-based values and intention to participate in the community were significantly linked to lower utility consumption in households. People who cared deeply about their town

  10. Forecasting landscape effects of Mississippi River diversions on elevation and accretion in Louisiana deltaic wetlands under future environmental uncertainty scenarios

    Science.gov (United States)

    Wang, Hongqing; Steyer, Gregory D.; Couvillion, Brady R.; John M. Rybczyk,; Beck, Holly J.; William J. Sleavin,; Ehab A. Meselhe,; Mead A. Allison,; Ronald G. Boustany,; Craig J. Fischenich,; Victor H. Rivera-Monroy,

    2014-01-01

    Large sediment diversions are proposed and expected to build new wetlands to alleviate the extensive wetland loss (5,000 km2) affecting coastal Louisiana during the last 78 years. Current assessment and prediction of the impacts of sediment diversions have focused on the capture and dispersal of both water and sediment on the adjacent river side and the immediate outfall marsh area. However, little is known about the effects of sediment diversions on existing wetland surface elevation and vertical accretion dynamics in the receiving basin at the landscape scale. In this study, we used a spatial wetland surface elevation model developed in support of Louisiana's 2012 Coastal Master Plan to examine such landscape-scale effects of sediment diversions. Multiple sediment diversion projects were incorporated in the model to simulate surface elevation and vertical accretion for the next 50 years (2010-2060) under two environmental (moderate and less optimistic) scenarios. Specifically, we examined landscape-scale surface elevation and vertical accretion trends under diversions with different geographical locations, diverted discharge rates, and geomorphic characteristics of the receiving basin. Model results indicate that small diversions ( 1,500 m3 s-1) are required to achieve landscape-level benefits to promote surface elevation via vertical accretion to keep pace with rising sea level.

  11. Free-Energy Landscape of the Dissolution of Gibbsite at High pH.

    Science.gov (United States)

    Shen, Zhizhang; Kerisit, Sebastien N; Stack, Andrew G; Rosso, Kevin M

    2018-03-27

    The individual elementary reactions involved in the dissolution of a solid into solution remain mostly speculative due to a lack of direct experimental probes. In this regard, we have applied atomistic simulations to map the free-energy landscape of the dissolution of gibbsite from a step edge as a model of metal hydroxide dissolution. The overall reaction combines kink formation and kink propagation. Two individual reactions were found to be rate-limiting for kink formation, that is, the displacement of Al from a step site to a ledge adatom site and its detachment from ledge/terrace adatom sites into the solution. As a result, a pool of mobile and labile adsorbed species, or adatoms, exists before the release of Al into solution. Because of the quasi-hexagonal symmetry of gibbsite, kink site propagation can occur in multiple directions. Overall, our results will enable the development of microscopic mechanistic models of metal oxide dissolution.

  12. Quantitative analysis of the publishing landscape in High-Energy Physics

    CERN Document Server

    Mele, S; Vigen, Jens; Yeomans, Joanne

    2006-01-01

    World-wide collaboration in high-energy physics (HEP) is a tradition which dates back several decades, with scientific publications mostly coauthored by scientists from different countries. This coauthorship phenomenon makes it difficult to identify precisely the "share" of each country in HEP scientific production. One year's worth of HEP scientific articles published in peer-reviewed journals is analysed and their authors are uniquely assigned to countries. This method allows the first correct estimation on a pro rata basis of the share of HEP scientific publishing among several countries and institutions. The results provide an interesting insight into the geographical collaborative patterns of the HEP community. The HEP publishing landscape is further analysed to provide information on the journals favoured by the HEP community and on the geographical variation of their author bases. These results provide quantitative input to the ongoing debate on the possible transition of HEP publishing to an Open Acce...

  13. Free Energy Landscape of the Dissolution of Gibbsite at High pH

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Zhizhang; Kerisit, Sebastien N.; Stack, Andrew G.; Rosso, Kevin M.

    2018-03-26

    The individual elementary reactions involved in the dissolution of a solid into solution remain mostly speculative due to a lack of suitable, direct experimental probes. In this regard, we have applied atomistic simulations to map the free energy landscape of the dissolution of gibbsite from a step edge, as a model of metal hydroxide dissolution. The overall reaction combines kink site formation and kink site propagation. Two individual reactions were found to be rate-limiting for kink site formation, that is, the displacement of Al from a step site to a ledge adatom site and its detachment from ledge/terrace adatom sites into the solution. As a result, a pool of mobile and labile Al adsorbed species, or adatoms, exists before the release of Al into solution. Because of the quasi-hexagonal symmetry of gibbsite, kink site propagation can occur in multiple directions. Overall, the simulation results will enable the development of microscopic mechanistic models of metal oxide dissolution.

  14. Resting and energy reserves of Aedes albopictus collected in common landscaping vegetation in St. Augustine, Florida.

    Science.gov (United States)

    Samson, Dayana M; Qualls, Whitney A; Roque, Deborah; Naranjo, Diana P; Alimi, Temitope; Arheart, Kristopher L; Müller, Günter C; Beier, John C; Xue, Rui-De

    2013-09-01

    The resting behavior of Aedes albopictus was evaluated by aspirating diurnal resting mosquitoes from common landscape vegetation in residential communities in St. Augustine, FL. Energy reserves of the resting mosquitoes were analyzed to determine if there was a correlation between mosquito resting habitat and energy accumulation. Six species of plants were selected and 9 collections of resting mosquitoes were aspirated from each plant using a modified John W. Hock backpack aspirator during June and July 2012. Eight mosquito species were collected, with Ae. albopictus representing 74% of the overall collection. The number of Ae. albopictus collected varied significantly with the species of vegetation. When comparing the vegetation and abundance of resting mosquitoes, the highest percentages of Ae. albopictus were collected resting on Ruellia brittoniana (Mexican petunia), Asplenium platyneuron (fern), Gibasis geniculate (Tahitian bridal veil), followed by Plumba goauriculata (plumbago), Setcreasea pallida (purple heart), and Hibiscus tiliaceus (hibiscus). There were significant differences in lipid and glycogen accumulation based on type of vegetation Ae. albopictus was found resting in. Resting mosquitoes' sugar reserves were not influenced by species of vegetation. However, there was an overall correlation between vegetation that serves as a resting habitat and energy reserve accumulation. The results of our study demonstrate the potential to target specific vegetation for control of diurnal resting mosquitoes.

  15. Landscapes for Energy and Wildlife: Conservation Prioritization for Golden Eagles across Large Spatial Scales.

    Science.gov (United States)

    Tack, Jason D; Fedy, Bradley C

    2015-01-01

    Proactive conservation planning for species requires the identification of important spatial attributes across ecologically relevant scales in a model-based framework. However, it is often difficult to develop predictive models, as the explanatory data required for model development across regional management scales is rarely available. Golden eagles are a large-ranging predator of conservation concern in the United States that may be negatively affected by wind energy development. Thus, identifying landscapes least likely to pose conflict between eagles and wind development via shared space prior to development will be critical for conserving populations in the face of imposing development. We used publically available data on golden eagle nests to generate predictive models of golden eagle nesting sites in Wyoming, USA, using a suite of environmental and anthropogenic variables. By overlaying predictive models of golden eagle nesting habitat with wind energy resource maps, we highlight areas of potential conflict among eagle nesting habitat and wind development. However, our results suggest that wind potential and the relative probability of golden eagle nesting are not necessarily spatially correlated. Indeed, the majority of our sample frame includes areas with disparate predictions between suitable nesting habitat and potential for developing wind energy resources. Map predictions cannot replace on-the-ground monitoring for potential risk of wind turbines on wildlife populations, though they provide industry and managers a useful framework to first assess potential development.

  16. The energy landscape, folding pathways and the kinetics of a knotted protein.

    Directory of Open Access Journals (Sweden)

    Michael C Prentiss

    2010-07-01

    Full Text Available The folding pathway and rate coefficients of the folding of a knotted protein are calculated for a potential energy function with minimal energetic frustration. A kinetic transition network is constructed using the discrete path sampling approach, and the resulting potential energy surface is visualized by constructing disconnectivity graphs. Owing to topological constraints, the low-lying portion of the landscape consists of three distinct regions, corresponding to the native knotted state and to configurations where either the N or C terminus is not yet folded into the knot. The fastest folding pathways from denatured states exhibit early formation of the N terminus portion of the knot and a rate-determining step where the C terminus is incorporated. The low-lying minima with the N terminus knotted and the C terminus free therefore constitute an off-pathway intermediate for this model. The insertion of both the N and C termini into the knot occurs late in the folding process, creating large energy barriers that are the rate limiting steps in the folding process. When compared to other protein folding proteins of a similar length, this system folds over six orders of magnitude more slowly.

  17. ENERGY REVOLUTION UNDER THE BRICS NATIONS

    Directory of Open Access Journals (Sweden)

    M. K. Sahu

    2016-01-01

    Full Text Available The BRICS countries are of critical importance to both supply and demand fundamentals of energy markets globally. Today BRICS plays a very important role in the system of international energy security. BRICS energy diversification is driven by concerns for energy security. The potential for a BRIC energy partnership is thus enormous. The development of the BRIC countries in the next coming decades will include demographic changes with a growing middle class population which will demand more energy and resources that our world has the potential to supply.A Green Energy Revolution is the panacea to solve major social, economic and envi­ronmental effects of their growing populations. This paper is an attempt to highlight the cooperation among the BRICS Nations for the development of Energy Sector and at the same time the concerning issue of climate change etc. It further discusses about the contribution of BRICS countries in the global economy. This paper also discusses about the role of the BRICS Nations in collaboration with the International Energy Agency.

  18. Achieving Energy Efficient Ship Operations Under Third Party Management

    DEFF Research Database (Denmark)

    Taudal Poulsen, René; Sornn-Friese, Henrik

    2015-01-01

    of time to produce and provide reliable energy efficiency information cause energy efficiency gaps. The paper brings together the energy efficiency and ship management literatures, demonstrating how ship management models influence energy efficiency in ship operations. Achieving energy efficiency in ship...... operations is particularly challenging under third party ship management. Finally, the paper discusses management implications for shipping companies, which outsource ship management to third parties.......Profitable energy saving measures are often not fully implemented in shipping, causing energy efficiency gaps. The paper identifies energy efficiency gaps in ship operations, and explores their causes. Lack of information on energy efficiency, lack of energy training at sea and onshore and lack...

  19. Regional carbon dioxide and energy fluxes from airborne observations using flight-path segmentation based on landscape characteristics

    Directory of Open Access Journals (Sweden)

    O. S. Vellinga

    2010-04-01

    Full Text Available This paper presents an analysis of regional fluxes obtained with a small aircraft over heterogeneous terrain in the south-west of France, during the large scale field experiment CERES'07. We use a method combining variable flight-path segmentation with basic airborne footprint analysis. The segmentation is based on topography, land use and soil type, using a.o. satellite imagery and digital maps. The segments are delineated using an average footprint length, based on all flights, and segment lengths, which are variable in space but not in time. The method results in segment averaged carbon and energy fluxes, which are shown to be representative of regional fluxes. Our analysis is focussed on carbon dioxide, heat and evaporative fluxes around solar noon. We will show that spatial and seasonal variations in the fluxes can be linked to the underlying landscape. In addition, a comparison between the airborne data and ground flux data is made to support our results. However, due to the incompleteness of ground data for some predominant vegetation types (even in such a data dense context, upscaling of ground data to regional fluxes was not possible. Without the comparison, we are still able to demonstrate that aircraft can provide direct and meaningful estimates of regional fluxes of energy and carbon dioxide.

  20. Africa's energy sector: energy availability and the underlying financial challenges

    International Nuclear Information System (INIS)

    Lebesa, Motselisi; Ndyeshobola, Ahmed.

    1994-01-01

    The objective of this paper is to provide a brief overview of energy availability in Africa and the attendant financing concerns in the African energy sector. The paper departs from three key premises: firstly that energy resources in Africa are abundant, but current trends in its consumption and inherent externalities are unsustainable. This abundance is also affected by social and political stability. Secondly, that the majority of Africa's population lacks access to adequate energy services. Poverty issues and effects undermine the urgency of energy and environmental concerns. Thirdly, that Africa's sustainable development calls for more energy supply not less. Future energy requirements and related supply and financing issues are discussed with the time horizon of the year 2020. (author)

  1. Energy production from grassland - Assessing the sustainability of different process chains under German conditions

    International Nuclear Information System (INIS)

    Roesch, Christine; Skarka, J.; Raab, K.; Stelzer, V.

    2009-01-01

    In many regions of Europe, grassland shapes the landscape and fulfils important functions in protecting nature, soil, and water. However, the traditional uses of grassland for forage production are vanishing with progress in breeding and structural adaptations in agriculture. On the other hand, the demand for biomass energy is rising due to political sustainability goals and financial measures to support renewable energy. Against this background, the Institute for Technology Assessment and Systems Analysis investigated the applicability, economic efficiency, and sustainability of different techniques for energy production from grassland as well as from grassland converted into maize fields or short-rotation poplars under German conditions. The results show that despite relatively high energy prices and the financial support for bioenergy, the effects of energy production from grassland on employment in agriculture and farmers' income are modest. What is beneficial are savings in non-renewable energy, reductions in greenhouse gas emissions, and local provision of energy carriers. If grassland biomass (grass silage or hay) is used for energy purposes, this brings the further advantages of preserving biodiversity and the cultural landscape and protecting of soil and groundwater. Negative impacts on sustainable development result from an increase in emissions, which leads to acidification, eutrophication, and risks to human health. The overall evaluation indicates that short-rotation poplars are comparatively advantageous from the economic and ecological point of view. Therefore, a development plan for grassland is required to identify areas where grassland could be used as an energy resource or where it would be favourable to install energy plantations with fast-growing perennial plants

  2. Energy landscape and diffusion kinetics of lithiated silicon: A kinetic activation-relaxation technique study

    Science.gov (United States)

    Trochet, Mickaël; Mousseau, Normand

    2017-10-01

    With large specific and volumetric capacity, lithiated silicon is an excellent anode for lithium-ion batteries. Its application is challenged today, however, by the formation of an amorphous a -LixSi phase associated with a large volume change that occurs at relatively low Li concentration and remains only very partly understood at the microscopic level. In this paper, we characterize the full energy landscape associated with the onset of Li insertion in crystalline Si as a first step for understanding the lithiation process. We identify the diffusion mechanisms and migration energies for one to ten Li atoms in a Si crystal as well as the average lifetime of small lithium aggregates, using the kinetic activation-relaxation technique (kART), an off-lattice kinetic Monte-Carlo method with on-the-fly catalog building capabilities coupled to a newly developed force field (ReaxFF) used as potential based on ab initio results. We show that the short lifetimes of the bound states (from meV to ten meV) mean that Li atoms move in the interstitial sublattice with little interactions, explaining how high Li concentration in Si can be reached.

  3. Sequence-dependent base-stacking stabilities guide tRNA folding energy landscapes.

    Science.gov (United States)

    Li, Rongzhong; Ge, Heming W; Cho, Samuel S

    2013-10-24

    The folding of bacterial tRNAs with disparate sequences has been observed to proceed in distinct folding mechanisms despite their structural similarity. To explore the folding landscapes of tRNA, we performed ion concentration-dependent coarse-grained TIS model MD simulations of several E. coli tRNAs to compare their thermodynamic melting profiles to the classical absorbance spectra of Crothers and co-workers. To independently validate our findings, we also performed atomistic empirical force field MD simulations of tRNAs, and we compared the base-to-base distances from coarse-grained and atomistic MD simulations to empirical base-stacking free energies. We then projected the free energies to the secondary structural elements of tRNA, and we observe distinct, parallel folding mechanisms whose differences can be inferred on the basis of their sequence-dependent base-stacking stabilities. In some cases, a premature, nonproductive folding intermediate corresponding to the Ψ hairpin loop must backtrack to the unfolded state before proceeding to the folded state. This observation suggests a possible explanation for the fast and slow phases observed in tRNA folding kinetics.

  4. Hybrid organic–inorganic inks flatten the energy landscape in colloidal quantum dot solids

    KAUST Repository

    Liu, Mengxia

    2016-11-14

    Bandtail states in disordered semiconductor materials result in losses in open-circuit voltage (Voc) and inhibit carrier transport in photovoltaics. For colloidal quantum dot (CQD) films that promise low-cost, large-area, air-stable photovoltaics, bandtails are determined by CQD synthetic polydispersity and inhomogeneous aggregation during the ligand-exchange process. Here we introduce a new method for the synthesis of solution-phase ligand-exchanged CQD inks that enable a flat energy landscape and an advantageously high packing density. In the solid state, these materials exhibit a sharper bandtail and reduced energy funnelling compared with the previous best CQD thin films for photovoltaics. Consequently, we demonstrate solar cells with higher Voc and more efficient charge injection into the electron acceptor, allowing the use of a closer-to-optimum bandgap to absorb more light. These enable the fabrication of CQD solar cells made via a solution-phase ligand exchange, with a certified power conversion efficiency of 11.28%. The devices are stable when stored in air, unencapsulated, for over 1,000 h.

  5. Hybrid organic-inorganic inks flatten the energy landscape in colloidal quantum dot solids

    Science.gov (United States)

    Liu, Mengxia; Voznyy, Oleksandr; Sabatini, Randy; García de Arquer, F. Pelayo; Munir, Rahim; Balawi, Ahmed Hesham; Lan, Xinzheng; Fan, Fengjia; Walters, Grant; Kirmani, Ahmad R.; Hoogland, Sjoerd; Laquai, Frédéric; Amassian, Aram; Sargent, Edward H.

    2017-02-01

    Bandtail states in disordered semiconductor materials result in losses in open-circuit voltage (Voc) and inhibit carrier transport in photovoltaics. For colloidal quantum dot (CQD) films that promise low-cost, large-area, air-stable photovoltaics, bandtails are determined by CQD synthetic polydispersity and inhomogeneous aggregation during the ligand-exchange process. Here we introduce a new method for the synthesis of solution-phase ligand-exchanged CQD inks that enable a flat energy landscape and an advantageously high packing density. In the solid state, these materials exhibit a sharper bandtail and reduced energy funnelling compared with the previous best CQD thin films for photovoltaics. Consequently, we demonstrate solar cells with higher Voc and more efficient charge injection into the electron acceptor, allowing the use of a closer-to-optimum bandgap to absorb more light. These enable the fabrication of CQD solar cells made via a solution-phase ligand exchange, with a certified power conversion efficiency of 11.28%. The devices are stable when stored in air, unencapsulated, for over 1,000 h.

  6. Energy transfer in turbulence under rotation

    Science.gov (United States)

    Buzzicotti, Michele; Aluie, Hussein; Biferale, Luca; Linkmann, Moritz

    2018-03-01

    It is known that rapidly rotating turbulent flows are characterized by the emergence of simultaneous upscale and downscale energy transfer. Indeed, both numerics and experiments show the formation of large-scale anisotropic vortices together with the development of small-scale dissipative structures. However the organization of interactions leading to this complex dynamics remains unclear. Two different mechanisms are known to be able to transfer energy upscale in a turbulent flow. The first is characterized by two-dimensional interactions among triads lying on the two-dimensional, three-component (2D3C)/slow manifold, namely on the Fourier plane perpendicular to the rotation axis. The second mechanism is three-dimensional and consists of interactions between triads with the same sign of helicity (homochiral). Here, we present a detailed numerical study of rotating flows using a suite of high-Reynolds-number direct numerical simulations (DNS) within different parameter regimes to analyze both upscale and downscale cascade ranges. We find that the upscale cascade at wave numbers close to the forcing scale is generated by increasingly dominant homochiral interactions which couple the three-dimensional bulk and the 2D3C plane. This coupling produces an accumulation of energy in the 2D3C plane, which then transfers energy to smaller wave numbers thanks to the two-dimensional mechanism. In the forward cascade range, we find that the energy transfer is dominated by heterochiral triads and is dominated primarily by interaction within the fast manifold where kz≠0 . We further analyze the energy transfer in different regions in the real-space domain. In particular, we distinguish high-strain from high-vorticity regions and we uncover that while the mean transfer is produced inside regions of strain, the rare but extreme events of energy transfer occur primarily inside the large-scale column vortices.

  7. Modeling landscape net ecosystem productivity (LandNEP) under alternative management regimes

    Science.gov (United States)

    Eugenie S. Euskirchen; Jiquan Chen; Harbin Li; Eric J. Gustafson; Thomas R. Crow

    2002-01-01

    Forests have been considered as a major carbon sink within the global carbon budget. However, a fragmented forest landscape varies significantly in its composition and age structure, and the amount of carbon sequestered at this level remains generally unknown to the scientific community. More precisely, the temporal dynamics and spatial distribution of net ecosystem...

  8. Comparing Nitrous Oxide Emissions from Three Residential Landscapes under Different Management Schemes Following Natural Rainfall Events

    Science.gov (United States)

    Cultural lawn management practices that produce aesthetically appealing landscapes may also create environmental conditions that stimulate soil nitrous oxide (N2O) emissions. The purpose of this study is to investigate the effects of lawn management practices on N2O fluxes from ...

  9. Energy management under policy and technology uncertainty

    International Nuclear Information System (INIS)

    Tylock, Steven M.; Seager, Thomas P.; Snell, Jeff; Bennett, Erin R.; Sweet, Don

    2012-01-01

    Energy managers in public agencies are subject to multiple and sometimes conflicting policy objectives regarding cost, environmental, and security concerns associated with alternative energy technologies. Making infrastructure investment decisions requires balancing different distributions of risks and benefits that are far from clear. For example, managers at permanent Army installations must incorporate Congressional legislative objectives, executive orders, Department of Defense directives, state laws and regulations, local restrictions, and multiple stakeholder concerns when undertaking new energy initiatives. Moreover, uncertainty with regard to alternative energy technologies is typically much greater than that associated with traditional technologies, both because the technologies themselves are continuously evolving and because the intermittent nature of many renewable technologies makes a certain level of uncertainty irreducible. This paper describes a novel stochastic multi-attribute analytic approach that allows users to explore different priorities or weighting schemes in combination with uncertainties related to technology performance. To illustrate the utility of this approach for understanding conflicting policy or stakeholder perspectives, prioritizing the need for more information, and making investment decisions, we apply this approach to an energy technology decision problem representative of a permanent military base. Highlights: ► Incorporate disparate criteria with uncertain performance. ► Analyze decisions with contrasting stakeholder positions. ► Interactively compare alternatives based on uncertain weighting. ► User friendly multi-criteria decision analysis (MCDA) tool.

  10. Past and future landscape dynamics in pasture-woodlands of the Swiss Jura Mountains under climate change

    Directory of Open Access Journals (Sweden)

    Alexander Peringer

    2013-09-01

    We present a refined version of the spatially explicit, dynamic simulation model WoodPaM with improved climate sensitivity of simulated vegetation. We investigate pasture-woodland dynamics by applying an innovative combination of retrospective simulations starting in the Middle Ages with prospective simulations following two climate change scenarios. The retrospective simulations demonstrate the strong dependency of the landscape mosaic on both climate and management. In high elevation mountain pastures, climate cooling during the Little Ice Age hindered simulated tree regeneration and reduced forage production of grasslands. Both led to an increase in open grassland and to a structural simplification of the landscape. In turn, climate warming afterwards showed the opposite effect. At lower elevations, high cattle stocking rates generally dominate simulated succession, leading to a slow development of quite homogenous landscapes whose structures are hardly affected by historical climate variability. Aerial photographs suggest that logging and windstorms critically shaped the current landscape, both homogenizing mosaic structures that emerge from selective grazing. Simulations of climate change scenarios suggest delayed but inevitable structural changes in the landscape mosaic and a temporary breakdown of the ecosystem service wood production. The population of currently dominating Norway spruce collapses due to simulated drought. Spruce is only slowly replaced either by beech under moderate warming or by Scots pine under extreme warming. In general, the shift in tree species dominance results in landscapes of less structural richness than today. In order to maintain the mosaic structure of pasture-woodlands, we recommend a future increase in cattle stocking on mountain pastures. The (re- introduction of mixed herds (cattle with horses, sheep, and goats could mitigate the simulated trend towards structural homogenization of the forest-grassland mosaic because

  11. Probing the energy landscape of alanine dipeptide and decalanine using temperature as a tunable parameter in molecular dynamics

    International Nuclear Information System (INIS)

    Chatterjee, A; Bhattacharya, S

    2016-01-01

    We perform several molecular dynamics (MD) calculations of solvated alanine dipeptide and decalanine in vacuum with temperature as a tunable parameter and in the process, generate Markov state models (MSMs) at each temperature. An interesting observation that the kinetic rates appear to obey the Arrhenius rate law allows us to predict the dynamics of alanine dipeptide at 300 K at the microsecond timescales using the nanoseconds long high temperature calculations without actually performing MD simulations at 300 K. We conclude that the energy landscape of alanine dipeptide contains superbasins deeper than k B T and determine the energy barriers associated with the moves from the Arrhenius rate expression. Similar insights regarding the energy landscape associated with folding/unfolding pathways of a deca-alanine molecule are obtained using kinetic rates calculated at different temperatures. (paper)

  12. Selling power : marketing energy under deregulation

    International Nuclear Information System (INIS)

    Drummond, J.; Hanna, F.

    2001-01-01

    This book discussed the marketing of energy in a deregulated environment. Experience from long distance telephone service providers has shown that historical dominance is not a guarantee for future success. As new brands are introduced and as consumer choice increases, so does the ability to change from one provider to another. Price is only one of the factors prompting that change. Old rules and practices do not bind new competitors who must face the challenge of open competition and must be aware of the ever-changing face of business. It was recommended that the strategic solution would be to build a brand and to develop significant market shares and create effective customer retention programs. This book focused on the elements that energy marketing professionals must use to maintain and increase share without product differentiation. It also explained how energy providers can effectively attract and retain customers over the long term while keeping marketing and service delivery costs down. It was suggested that small players can compete with the growing strength of regional providers by creating new alliances between larger energy conglomerates. The chapters of the book were entitled: (1) Introduction, (2) The Goals of Deregulation, (3) Strategic Marketing Choices, (4) Relationship Marketing, (5) The Role of Customer Service, (6) The Question of Outsourcing, and (7) Final Thoughts and Observations. 24 refs., 3 figs

  13. Energy-landscape paving for prediction of face-centered-cubic hydrophobic-hydrophilic lattice model proteins.

    Science.gov (United States)

    Liu, Jingfa; Song, Beibei; Liu, Zhaoxia; Huang, Weibo; Sun, Yuanyuan; Liu, Wenjie

    2013-11-01

    Protein structure prediction (PSP) is a classical NP-hard problem in computational biology. The energy-landscape paving (ELP) method is a class of heuristic global optimization algorithm, and has been successfully applied to solving many optimization problems with complex energy landscapes in the continuous space. By putting forward a new update mechanism of the histogram function in ELP and incorporating the generation of initial conformation based on the greedy strategy and the neighborhood search strategy based on pull moves into ELP, an improved energy-landscape paving (ELP+) method is put forward. Twelve general benchmark instances are first tested on both two-dimensional and three-dimensional (3D) face-centered-cubic (fcc) hydrophobic-hydrophilic (HP) lattice models. The lowest energies by ELP+ are as good as or better than those of other methods in the literature for all instances. Then, five sets of larger-scale instances, denoted by S, R, F90, F180, and CASP target instances on the 3D FCC HP lattice model are tested. The proposed algorithm finds lower energies than those by the five other methods in literature. Not unexpectedly, this is particularly pronounced for the longer sequences considered. Computational results show that ELP+ is an effective method for PSP on the fcc HP lattice model.

  14. Can the energy gap in the protein-ligand binding energy landscape be used as a descriptor in virtual ligand screening?

    Directory of Open Access Journals (Sweden)

    Arsen V Grigoryan

    Full Text Available The ranking of scores of individual chemicals within a large screening library is a crucial step in virtual screening (VS for drug discovery. Previous studies showed that the quality of protein-ligand recognition can be improved using spectrum properties and the shape of the binding energy landscape. Here, we investigate whether the energy gap, defined as the difference between the lowest energy pose generated by a docking experiment and the average energy of all other generated poses and inferred to be a measure of the binding energy landscape sharpness, can improve the separation power between true binders and decoys with respect to the use of the best docking score. We performed retrospective single- and multiple-receptor conformation VS experiments in a diverse benchmark of 40 domains from 38 therapeutically relevant protein targets. Also, we tested the performance of the energy gap on 36 protein targets from the Directory of Useful Decoys (DUD. The results indicate that the energy gap outperforms the best docking score in its ability to discriminate between true binders and decoys, and true binders tend to have larger energy gaps than decoys. Furthermore, we used the energy gap as a descriptor to measure the height of the native binding phase and obtained a significant increase in the success rate of near native binding pose identification when the ligand binding conformations within the boundaries of the native binding phase were considered. The performance of the energy gap was also evaluated on an independent test case of VS-identified PKR-like ER-localized eIF2α kinase (PERK inhibitors. We found that the energy gap was superior to the best docking score in its ability to more highly rank active compounds from inactive ones. These results suggest that the energy gap of the protein-ligand binding energy landscape is a valuable descriptor for use in VS.

  15. Jets and Underlying Events at LHC Energies

    Science.gov (United States)

    Agócs, A. G.; Barnaföldi, G. G.; Lévai, P.

    2011-01-01

    Jet-matter interaction remains a central question and a theoretical challenge in heavy-ion physics and might become important in high-multiplicity events in proton-proton collisions at LHC energies. Full jet measurement at LHC offer the proper tool to investigate energy loss process and fragmentation of hard parton in the medium. Since jet reconstruction will be constrained to small cone sizes, then study of the connection between jets and surrounding environment provides a further possibility to extend our exploration. We study jets at = 14 TeV and pp collisions at = 7 TeV. We analyze the flavor components in jet-like environments. We introduce a definition for surrounding cones/belts and investigate flavor dependence and correlation of different hadron species produced in jets. Here, we focus on proton-triggered correlations. Our analysis can be extended for heavy ion collisions.

  16. Energy: they said it under oath

    International Nuclear Information System (INIS)

    Gay, Michel

    2013-01-01

    The author aims at denouncing the content of a report made by a parliamentary inquiry commission on the actual cost of electricity. He notably denounces the influence of the ecologist parliamentary group which wants the people believe in a better future based on the development of renewable energies and giving up nuclear. Therefore, he proposes the transcriptions of the different hearings on which the report was based, and outlines extracts which have been conjured away by the senator's report

  17. pH-Responsive Self-Assembly of Polysaccharide through a Rugged Energy Landscape.

    Science.gov (United States)

    Morrow, Brian H; Payne, Gregory F; Shen, Jana

    2015-10-14

    Self-assembling polysaccharides can form complex networks with structures and properties highly dependent on the sequence of triggering cues. Controlling the emergence of such networks provides an opportunity to create soft matter with unique features; however, it requires a detailed understanding of the subtle balance between the attractive and repulsive forces that drives the stimuli-induced self-assembly. Here we employ all-atom molecular dynamics simulations on the order of 100 ns to study the mechanisms of the pH-responsive gelation of the weakly basic aminopolysaccharide chitosan. We find that low pH induces a sharp transition from gel to soluble state, analogous to pH-dependent folding of proteins, while at neutral and high pH self-assembly occurs via a rugged energy landscape, reminiscent of RNA folding. A surprising role of salt is to lubricate the conformational search for the thermodynamically stable states. Although our simulations represent the early events in the self-assembly process of chitosan, which may take seconds or minutes to complete, the atomically detailed insights are consistent with recent experimental observations and provide a basis for understanding how environmental conditions modulate the structure and mechanical properties of the self-assembled polysaccharide systems. The ability to control structure and properties via modification of process conditions will aid in the technological efforts to create complex soft matter with applications ranging from bioelectronics to regenerative medicine.

  18. Pest-Suppression Potential of Midwestern Landscapes under Contrasting Bioenergy Scenarios

    OpenAIRE

    Meehan, Timothy D.; Werling, Ben P.; Landis, Douglas A.; Gratton, Claudio

    2012-01-01

    Biomass crops grown on marginal soils are expected to fuel an emerging bioenergy industry in the United States. Bioenergy crop choice and position in the landscape could have important impacts on a range of ecosystem services, including natural pest-suppression (biocontrol services) provided by predatory arthropods. In this study we use predation rates of three sentinel crop pests to develop a biocontrol index (BCI) summarizing pest-suppression potential in corn and perennial grass-based bioe...

  19. Quasiharmonic analysis of protein energy landscapes from pressure-temperature molecular dynamics simulations

    Science.gov (United States)

    Rodgers, Jocelyn M.; Hemley, Russell J.; Ichiye, Toshiko

    2017-09-01

    Positional fluctuations of an atom in a protein can be described as motion in an effective local energy minimum created by the surrounding protein atoms. The dependence of atomic fluctuations on both temperature (T) and pressure (P) has been used to probe the nature of these minima, which are generally described as harmonic in experiments such as x-ray crystallography and neutron scattering. Here, a quasiharmonic analysis method is presented in which the P-T dependence of atomic fluctuations is in terms of an intrinsic isobaric thermal expansivity αP and an intrinsic isothermal compressibility κT. The method is tested on previously reported mean-square displacements from P-T molecular dynamics simulations of lysozyme, which were interpreted to have a pressure-independent dynamical transition Tg near 200 K and a change in the pressure dependence near 480 MPa. Our quasiharmonic analysis of the same data shows that the P-T dependence can be described in terms of αP and κT where below Tg, the temperature dependence is frozen at the Tg value. In addition, the purported transition at 480 MPa is reinterpreted as a consequence of the pressure dependence of Tg and the quasiharmonic frequencies. The former also indicates that barrier heights between substates are pressure dependent in these data. Furthermore, the insights gained from this quasiharmonic analysis, which was of the energy landscape near the native state of a protein, suggest that similar analyses of other simulations may be useful in understanding such phenomena as pressure-induced protein unfolding.

  20. Efficient Determination of Free Energy Landscapes in Multiple Dimensions from Biased Umbrella Sampling Simulations Using Linear Regression.

    Science.gov (United States)

    Meng, Yilin; Roux, Benoît

    2015-08-11

    The weighted histogram analysis method (WHAM) is a standard protocol for postprocessing the information from biased umbrella sampling simulations to construct the potential of mean force with respect to a set of order parameters. By virtue of the WHAM equations, the unbiased density of state is determined by satisfying a self-consistent condition through an iterative procedure. While the method works very effectively when the number of order parameters is small, its computational cost grows rapidly in higher dimension. Here, we present a simple and efficient alternative strategy, which avoids solving the self-consistent WHAM equations iteratively. An efficient multivariate linear regression framework is utilized to link the biased probability densities of individual umbrella windows and yield an unbiased global free energy landscape in the space of order parameters. It is demonstrated with practical examples that free energy landscapes that are comparable in accuracy to WHAM can be generated at a small fraction of the cost.

  1. Enhanced, targeted sampling of high-dimensional free-energy landscapes using variationally enhanced sampling, with an application to chignolin.

    Science.gov (United States)

    Shaffer, Patrick; Valsson, Omar; Parrinello, Michele

    2016-02-02

    The capabilities of molecular simulations have been greatly extended by a number of widely used enhanced sampling methods that facilitate escaping from metastable states and crossing large barriers. Despite these developments there are still many problems which remain out of reach for these methods which has led to a vigorous effort in this area. One of the most important problems that remains unsolved is sampling high-dimensional free-energy landscapes and systems that are not easily described by a small number of collective variables. In this work we demonstrate a new way to compute free-energy landscapes of high dimensionality based on the previously introduced variationally enhanced sampling, and we apply it to the miniprotein chignolin.

  2. Enhanced, targeted sampling of high-dimensional free-energy landscapes using variationally enhanced sampling, with an application to chignolin

    Science.gov (United States)

    Shaffer, Patrick; Valsson, Omar; Parrinello, Michele

    2016-01-01

    The capabilities of molecular simulations have been greatly extended by a number of widely used enhanced sampling methods that facilitate escaping from metastable states and crossing large barriers. Despite these developments there are still many problems which remain out of reach for these methods which has led to a vigorous effort in this area. One of the most important problems that remains unsolved is sampling high-dimensional free-energy landscapes and systems that are not easily described by a small number of collective variables. In this work we demonstrate a new way to compute free-energy landscapes of high dimensionality based on the previously introduced variationally enhanced sampling, and we apply it to the miniprotein chignolin. PMID:26787868

  3. Climatic effects of 30 years of landscape change over the Greater Phoenix, Arizona, region: 1. Surface energy budget changes

    Science.gov (United States)

    Georgescu, M.; Miguez-Macho, G.; Steyaert, L.T.; Weaver, C.P.

    2009-01-01

    This paper is part 1 of a two-part study that evaluates the climatic effects of recent landscape change for one of the nation's most rapidly expanding metropolitan complexes, the Greater Phoenix, Arizona, region. The region's landscape evolution over an approximate 30-year period since the early 1970s is documented on the basis of analyses of Landsat images and land use/land cover (LULC) data sets derived from aerial photography (1973) and Landsat (1992 and 2001). High-resolution, Regional Atmospheric Modeling System (RAMS), simulations (2-km grid spacing) are used in conjunction with consistently defined land cover data sets and associated biophysical parameters for the circa 1973, circa 1992, and circa 2001 time periods to quantify the impacts of intensive land use changes on the July surface temperatures and the surface radiation and energy budgets for the Greater Phoenix region. The main findings are as follows: since the early 1970s the region's landscape has been altered by a significant increase in urban/suburban land area, primarily at the expense of decreasing plots of irrigated agriculture and secondarily by the conversion of seminatural shrubland. Mean regional temperatures for the circa 2001 landscape were 0.12??C warmer than the circa 1973 landscape, with maximum temperature differences, located over regions of greatest urbanization, in excess of 1??C. The significant reduction in irrigated agriculture, for the circa 2001 relative to the circa 1973 landscape, resulted in dew point temperature decreases in excess of 1??C. The effect of distinct land use conversion themes (e.g., conversion from irrigated agriculture to urban land) was also examined to evaluate how the most important conversion themes have each contributed to the region's changing climate. The two urbanization themes studied (from an initial landscape of irrigated agriculture and seminatural shrubland) have the greatest positive effect on near-surface temperature, increasing maximum daily

  4. Landscape relatedness

    DEFF Research Database (Denmark)

    Norman, Anita J; Strønen, Astrid Vik; Fuglstad, Geir-Arne

    2017-01-01

    Context Methods for detecting contemporary, fine-scale population genetic structure in continuous populations are scarce. Yet such methods are vital for ecological and conservation studies, particularly under a changing landscape. Objectives Here we present a novel, spatially explicit method...... that we call landscape relatedness (LandRel). With this method, we aim to detect contemporary, fine-scale population structure that is sensitive to spatial and temporal changes in the landscape. Methods We interpolate spatially determined relatedness values based on SNP genotypes across the landscape....... Interpolations are calculated using the Bayesian inference approach integrated nested Laplace approximation. We empirically tested this method on a continuous population of brown bears (Ursus arctos) spanning two counties in Sweden. Results Two areas were identified as differentiated from the remaining...

  5. Elephant population growth in Kruger National Park, South Africa, under a landscape management approach

    Directory of Open Access Journals (Sweden)

    Sam M. Ferreira

    2017-08-01

    Full Text Available South African National Parks (SANParks manage landscapes rather than numbers of elephants (Loxodonta africana to mitigate the effects that elephants may have on biodiversity, tourism and stakeholder conservation values associated with protected areas. This management philosophy imposes spatial variability of critical resources on elephants. Restoration of such ecological processes through less intensive management predicts a reduction in population growth rates from the eras of intensive management. We collated aerial survey data since 1995 and conducted an aerial total count using a helicopter observation platform during 2015. A minimum of 17 086 elephants were resident in the Kruger National Park (KNP in 2015, growing at 4.2% per annum over the last generation of elephants (i.e. 12 years, compared to 6.5% annual population growth noted during the intensive management era ending in 1994. This may come from responses of elephants to density and environmental factors manifested through reduced birth rates and increased mortality rates. Authorities should continue to evaluate the demographic responses of elephants to landscape scale interventions directed at restoring the limitation of spatial variance in resource distribution on elephant spatiotemporal dynamics and the consequences that may have for other conservation values. Conservation implications: Conservation managers should continue with surveying elephants in a way that allows the extraction of key variables. Such variables should focus on measures that reflect on how theory predicts elephants should respond to management interventions.

  6. The Shifting Landscape of Ratepayer-Funded Energy Efficiency in the U.S.

    Energy Technology Data Exchange (ETDEWEB)

    Barbose, Galen L; Goldman, Charles; Schlegel, Jeff

    2009-07-13

    , medium and high projections of future energy efficiency spending and savings. Depending on how aggressively and effectively states implement these policies, we estimate that spending on ratepayer-funded energy efficiency could increase from $3.1 billion in 2008 to more than $12 billion (nominal dollars) per year by 2020 in our high case, a growth rate in spending of about 12% per year. Annual electricity savings nationally could triple from an estimated 0.3% of retail electricity sales in 2008 to 0.9% of retail electricity sales in 2020. In the low and medium scenarios, ratepayer funding for electric and gas energy efficiency in the U.S. would increase to $5.4 and $7.5 billion, respectively, by 2020. What are the implications of such a scale-up of ratepayer-funded energy efficiency activity for national energy policy, such as a national EEPS or future carbon regulations? Can a ramp-up of this scale be achieved, and what practical constraints might slow these efforts? This paper addresses these questions by first providing an overview of recent trends in state policies pertaining to ratepayer-funded energy efficiency programs in the U.S. The paper then presents our set of projections of future spending and savings from such programs, highlighting key themes. Projected energy savings are compared to what might be required under a future national EEPS (or broader clean energy standard that includes energy efficiency), in order to gauge the potential incremental impact of such policies. In addition, the carbon emission reductions associated with our projection of energy savings from ratepayer-funded programs is compared to the total emission reductions that might be required under the American Clean Energy and Security Act of 2009 (aka, the Waxman-Markey bill), which was passed by the U.S. House of Representatives in June 2009 and would establish a cap on total greenhouse gas emission for many sectors of the U.S. economy. Last, the paper discusses some of the major obstacles

  7. Changing human landscapes under a changing climate: considerations for climate assessments.

    Science.gov (United States)

    Perdinan; Winkler, Julie A

    2014-01-01

    Climate change is a fundamental aspect of the Anthropocene. Climate assessments are frequently undertaken to evaluate climate change impacts, vulnerability, and adaptive capacity. Assessments are complex endeavors with numerous challenges. Five aspects of a climate assessment that can be particularly challenging are highlighted: choice of assessment strategy, incorporation of spatial linkages and interactions, the constraints of climate observations, interpretation of a climate projection ensemble, uncertainty associated with weather/climate dependency models, and consideration of landscape-climate influences. In addition, a climate assessment strategy that incorporates both traditional "top-down" and "bottom-up" methods is proposed for assessments of adaptation options at the local/regional scale. Uncertainties associated with climate observations and projections and with weather/climate dependency (i.e., response) models are incorporated into the assessment through the "top-down" component, and stakeholder knowledge and experience are included through the "bottom-up" component. Considerable further research is required to improve assessment strategies and the usefulness and usability of assessment findings. In particular, new methods are needed which better incorporate spatial linkages and interactions, yet maintain the fine grain detail needed for decision making at the local and regional scales. Also, new methods are needed which go beyond sensitivity analyses of the relative contribution of land use and land cover changes on local/regional climate to more explicitly consider landscape-climate interactions in the context of uncertain future climates. Assessment teams must clearly communicate the choices made when designing an assessment and recognize the implications of these choices on the interpretation and application of the assessment findings.

  8. Municipal Energy Planning under Conditions of Globalization: Imperatives and Objectives

    Directory of Open Access Journals (Sweden)

    Horban Vasylyna B.

    2017-12-01

    Full Text Available The article reveals the importance of energy planning for local authorities in the path of achieving the goals of sustainable development. The quintessence of energy planning in territorial communities of Ukraine and Europe has been outlined from the perspective of analyzing the infrastructure sectors of the municipal economy. The article is based on observing certain international methodologies related to local energy and climate planning. The evolution of Covenant of Mayors initiative is briefly described with a focus on its intensive expanding in terms of energy and climate issues. The experience in the development of municipal sustainable energy and climate action plans in European countries and Ukraine is studied. A survey of empirical data on the consumption of fuel and energy resources and greenhouse gas emissions in territorial communities of Ukraine and European countries is conducted. The European methodological guidelines on the subject under study are highlighted based on the key policy documents. A few practical examples of Ukrainian and European cities are presented in order to illustrate possible actions corresponding to the defined problem. A systematic framework is proposed to describe the various and complex aspects of energy planning in cities with regard to rational implementation of energy efficient measures. The innovative mechanisms, main barriers and opportunities for the effective implementation of energy efficient projects in territorial communities of Ukraine and European countries are revealed. It is substantiated that under the current conditions of globalization, using project-oriented paradigm, municipal energy planning instruments become key motivational factors for development sustainable energy policy.

  9. Metal azides under pressure: An emerging class of high energy ...

    Indian Academy of Sciences (India)

    Metal azides are well-known for their explosive properties such as detonation or deflagration. As chemically pure sources of nitrogen, alkali metal azides under high pressure have the ability to form polymeric nitrogen, an ultimate green high energy density material with energy density three times greater than that of known ...

  10. Metal azides under pressure: An emerging class of high energy ...

    Indian Academy of Sciences (India)

    Abstract. Metal azides are well-known for their explosive properties such as detonation or deflagration. As chemically pure sources of nitrogen, alkali metal azides under high pressure have the ability to form polymeric nitrogen, an ultimate green high energy density material with energy density three times greater than that ...

  11. The inherent dynamics of a molecular liquid: Geodesic pathways through the potential energy landscape of a liquid of linear molecules

    Science.gov (United States)

    Jacobson, Daniel; Stratt, Richard M.

    2014-05-01

    Because the geodesic pathways that a liquid follows through its potential energy landscape govern its slow, diffusive motion, we suggest that these pathways are logical candidates for the title of a liquid's "inherent dynamics." Like their namesake "inherent structures," these objects are simply features of the system's potential energy surface and thus provide views of the system's structural evolution unobstructed by thermal kinetic energy. This paper shows how these geodesic pathways can be computed for a liquid of linear molecules, allowing us to see precisely how such molecular liquids mix rotational and translational degrees of freedom into their dynamics. The ratio of translational to rotational components of the geodesic path lengths, for example, is significantly larger than would be expected on equipartition grounds, with a value that scales with the molecular aspect ratio. These and other features of the geodesics are consistent with a picture in which molecular reorientation adiabatically follows translation—molecules largely thread their way through narrow channels available in the potential energy landscape.

  12. Nature-based solutions for urban landscapes under post-industrialization and globalization: Barcelona versus Shanghai.

    Science.gov (United States)

    Fan, Peilei; Ouyang, Zutao; Basnou, Corina; Pino, Joan; Park, Hogeun; Chen, Jiquan

    2017-07-01

    Using Barcelona and Shanghai as case studies, we examined the nature-based solutions (NBS) in urban settings-specifically within cities experiencing post-industrialization and globalization. Our specific research questions are: (1) What are the spatiotemporal changes in urban built-up land and green space in Barcelona and Shanghai? (2) What are the relationships between economic development, exemplified by post-industrialization, globalization, and urban green space? Urban land use and green space change were evaluated using data derived from a variety of sources, including satellite images, landscape matrix indicators, and a land conversion matrix. The relationships between economic development, globalization, and environmental quality were analyzed through partial least squares structural equation modeling based on secondary statistical data. Both Barcelona and Shanghai have undergone rapid urbanization, with urban expansion in Barcelona beginning in the 1960s-1970s and in Shanghai in the last decade. While Barcelona's urban green space and green space per capita began declining between the 1950s and 1990s, they increased slightly over the past two decades. Shanghai, however, has consistently and significantly improved urban green space and green space per capita over the past six decades, especially since the economic reform in 1978. Economic development has a direct and significant influence on urban green space for both cities and post-industrialization had served as the main driving force for urban landscape change in Barcelona and Shanghai. Based on secondary statistical and qualitative data from on-site observations and interviews with local experts, we highlighted the institution's role in NBS planning. Furthermore, aspiration to become a global or globalizing city motivated both cities to use NBS planning as a place-making tool to attract global investment, which is reflected in various governing policies and regulations. The cities' effort to achieve a

  13. Interactions of landscape disturbances and climate change dictate ecological pattern and process: spatial modeling of wildfire, insect, and disease dynamics under future climates

    Science.gov (United States)

    Loehman, Rachel A.; Keane, Robert E.; Holsinger, Lisa M.; Wu, Zhiwei

    2016-01-01

    ContextInteractions among disturbances, climate, and vegetation influence landscape patterns and ecosystem processes. Climate changes, exotic invasions, beetle outbreaks, altered fire regimes, and human activities may interact to produce landscapes that appear and function beyond historical analogs.ObjectivesWe used the mechanistic ecosystem-fire process model FireBGCv2 to model interactions of wildland fire, mountain pine beetle (Dendroctonus ponderosae), and white pine blister rust (Cronartium ribicola) under current and future climates, across three diverse study areas.MethodsWe assessed changes in tree basal area as a measure of landscape response over a 300-year simulation period for the Crown of the Continent in north-central Montana, East Fork of the Bitterroot River in western Montana, and Yellowstone Central Plateau in western Wyoming, USA.ResultsInteracting disturbances reduced overall basal area via increased tree mortality of host species. Wildfire decreased basal area more than beetles or rust, and disturbance interactions modeled under future climate significantly altered landscape basal area as compared with no-disturbance and current climate scenarios. Responses varied among landscapes depending on species composition, sensitivity to fire, and pathogen and beetle suitability and susceptibility.ConclusionsUnderstanding disturbance interactions is critical for managing landscapes because forest responses to wildfires, pathogens, and beetle attacks may offset or exacerbate climate influences, with consequences for wildlife, carbon, and biodiversity.

  14. Land cover change in the zone of sporadic permafrost causes shift in landscape-scale turbulent energy fluxes

    Science.gov (United States)

    Helbig, M.; Wischnewski, K.; Kljun, N.; Chasmer, L.; Quinton, W. L.; Detto, M.; Sonnentag, O.

    2015-12-01

    current heterogeneous to a homogeneous bog landscape could lead to a decrease in the maximum PBL height by about 700 m and to a decrease in regional Ta by 1 to 2 K. Our results show clearly that permafrost degradation and forest cover shifts will affect local and regional surface energy balances in the boreal zone and could represent important modifiers of future climates.

  15. Sediment accumulation in prairie wetlands under a changing climate: The relative roles of landscape and precipitation

    Science.gov (United States)

    Skagen, Susan K.; Burris, Lucy E.; Granfors, Diane A.

    2016-01-01

    Sediment accumulation threatens the viability and hydrologic functioning of many naturally formed depressional wetlands across the interior regions of North America. These wetlands provide many ecosystem services and vital habitats for diverse plant and animal communities. Climate change may further impact sediment accumulation rates in the context of current land use patterns. We estimated sediment accretion in wetlands within a region renowned for its large populations of breeding waterfowl and migrant shorebirds and examined the relative roles of precipitation and land use context in the sedimentation process. We modeled rates of sediment accumulation from 1971 through 2100 using the Revised Universal Soil Loss Equation (RUSLE) with a sediment delivery ratio and the Unit Stream Power Erosion Deposition model (USPED). These models predicted that by 2100, 21–33 % of wetlands filled completely with sediment and 27–46 % filled by half with sediments; estimates are consistent with measured sediment accumulation rates in the region reported by empirical studies. Sediment accumulation rates were strongly influenced by size of the catchment, greater coverage of tilled landscape within the catchment, and steeper slopes. Conservation efforts that incorporate the relative risk of infilling of wetlands with sediments, thus emphasizing areas of high topographic relief and large watersheds, may benefit wetland-dependent biota.

  16. Determination of ubiquitin fitness landscapes under different chemical stresses in a classroom setting

    Science.gov (United States)

    Mavor, David; Barlow, Kyle; Thompson, Samuel; Barad, Benjamin A; Bonny, Alain R; Cario, Clinton L; Gaskins, Garrett; Liu, Zairan; Deming, Laura; Axen, Seth D; Caceres, Elena; Chen, Weilin; Cuesta, Adolfo; Gate, Rachel E; Green, Evan M; Hulce, Kaitlin R; Ji, Weiyue; Kenner, Lillian R; Mensa, Bruk; Morinishi, Leanna S; Moss, Steven M; Mravic, Marco; Muir, Ryan K; Niekamp, Stefan; Nnadi, Chimno I; Palovcak, Eugene; Poss, Erin M; Ross, Tyler D; Salcedo, Eugenia C; See, Stephanie K; Subramaniam, Meena; Wong, Allison W; Li, Jennifer; Thorn, Kurt S; Conchúir, Shane Ó; Roscoe, Benjamin P; Chow, Eric D; DeRisi, Joseph L; Kortemme, Tanja; Bolon, Daniel N; Fraser, James S

    2016-01-01

    Ubiquitin is essential for eukaryotic life and varies in only 3 amino acid positions between yeast and humans. However, recent deep sequencing studies indicate that ubiquitin is highly tolerant to single mutations. We hypothesized that this tolerance would be reduced by chemically induced physiologic perturbations. To test this hypothesis, a class of first year UCSF graduate students employed deep mutational scanning to determine the fitness landscape of all possible single residue mutations in the presence of five different small molecule perturbations. These perturbations uncover 'shared sensitized positions' localized to areas around the hydrophobic patch and the C-terminus. In addition, we identified perturbation specific effects such as a sensitization of His68 in HU and a tolerance to mutation at Lys63 in DTT. Our data show how chemical stresses can reduce buffering effects in the ubiquitin proteasome system. Finally, this study demonstrates the potential of lab-based interdisciplinary graduate curriculum. DOI: http://dx.doi.org/10.7554/eLife.15802.001 PMID:27111525

  17. Enteric disease surveillance under the AFHSC-GEIS: Current efforts, landscape analysis and vision forward

    Directory of Open Access Journals (Sweden)

    Kasper Matthew R

    2011-03-01

    Full Text Available Abstract The mission of the Armed Forces Health Surveillance Center, Division of Global Emerging Infections Surveillance and Response System (AFHSC-GEIS is to support global public health and to counter infectious disease threats to the United States Armed Forces, including newly identified agents or those increasing in incidence. Enteric diseases are a growing threat to U.S. forces, which must be ready to deploy to austere environments where the risk of exposure to enteropathogens may be significant and where routine prevention efforts may be impractical. In this report, the authors review the recent activities of AFHSC-GEIS partner laboratories in regards to enteric disease surveillance, prevention and response. Each partner identified recent accomplishments, including support for regional networks. AFHSC/GEIS partners also completed a Strengths, Weaknesses, Opportunities and Threats (SWOT survey as part of a landscape analysis of global enteric surveillance efforts. The current strengths of this network include excellent laboratory infrastructure, equipment and personnel that provide the opportunity for high-quality epidemiological studies and test platforms for point-of-care diagnostics. Weaknesses include inconsistent guidance and a splintered reporting system that hampers the comparison of data across regions or longitudinally. The newly chartered Enterics Surveillance Steering Committee (ESSC is intended to provide clear mission guidance, a structured project review process, and central data management and analysis in support of rationally directed enteric disease surveillance efforts.

  18. Model analyses for sustainable energy supply under CO2 restrictions

    International Nuclear Information System (INIS)

    Matsuhashi, Ryuji; Ishitani, Hisashi.

    1995-01-01

    This paper aims at clarifying key points for realizing sustainable energy supply under restrictions on CO 2 emissions. For this purpose, possibility of solar breeding system is investigated as a key technology for the sustainable energy supply. The authors describe their mathematical model simulating global energy supply and demand in ultra-long term. Depletion of non-renewable resources and constraints on CO 2 emissions are taken into consideration in the model. Computed results have shown that present energy system based on non-renewable resources shifts to a system based on renewable resources in the ultra-long term with appropriate incentives

  19. Landscape preservation under ice? In-situ 10Be and 26Al from summit surfaces along Sognefjord, Norway

    DEFF Research Database (Denmark)

    Andersen, Jane Lund; Egholm, David Lundbek; Knudsen, Mads Faurschou

    then be used to determine the total Quaternary bedrock erosion between the summits. However, the amount of Quaternary erosion of these summit flats remains debated (e.g. Steer, 2012) Here, we present an extensive new dataset of in-situ produced cosmogenic 10Be and 26Al in bedrock and boulders from high...... and flat summits along a 200 km long transect from the coast to the inner parts of Sognefjorden. Our results indicate substantial glacial modification of the summits within the last 50 ka. Close to the coast, at an elevation of around 700 meters, the cosmogenic nuclide signal was reset around the Younger...... et al. Landscape preservation under Fennoscandian ice sheets determined from in situ produced 10 Be and 26 Al. Earth and Planetary Science Letters 201(2), 397-406, 2002. Gjermundsen et al. Minimal erosion of Arctic alpine topography during late Quaternary glaciation. Nature Geoscience 8(10), 789...

  20. Analyzing high resolution topography for advancing the understanding of mass and energy transfer through landscapes: A review

    Science.gov (United States)

    Passaiacquaa, Paola; Belmont, Patrick; Staley, Dennis M.; Simley, Jeffery; Arrowsmith, J. Ramon; Bode, Collin A.; Crosby, Christopher; DeLong, Stephen; Glenn, Nancy; Kelly, Sara; Lague, Dimitri; Sangireddy, Harish; Schaffrath, Keelin; Tarboton, David; Wasklewicz, Thad; Wheaton, Joseph

    2015-01-01

    The study of mass and energy transfer across landscapes has recently evolved to comprehensive considerations acknowledging the role of biota and humans as geomorphic agents, as well as the importance of small-scale landscape features. A contributing and supporting factor to this evolution is the emergence over the last two decades of technologies able to acquire high resolution topography (HRT) (meter and sub-meter resolution) data. Landscape features can now be captured at an appropriately fine spatial resolution at which surface processes operate; this has revolutionized the way we study Earth-surface processes. The wealth of information contained in HRT also presents considerable challenges. For example, selection of the most appropriate type of HRT data for a given application is not trivial. No definitive approach exists for identifying and filtering erroneous or unwanted data, yet inappropriate filtering can create artifacts or eliminate/distort critical features. Estimates of errors and uncertainty are often poorly defined and typically fail to represent the spatial heterogeneity of the dataset, which may introduce bias or error for many analyses. For ease of use, gridded products are typically preferred rather than the more information-rich point cloud representations. Thus many users take advantage of only a fraction of the available data, which has furthermore been subjected to a series of operations often not known or investigated by the user. Lastly, standard HRT analysis work-flows are yet to be established for many popular HRT operations, which has contributed to the limited use of point cloud data.In this review, we identify key research questions relevant to the Earth-surface processes community within the theme of mass and energy transfer across landscapes and offer guidance on how to identify the most appropriate topographic data type for the analysis of interest. We describe the operations commonly performed from raw data to raster products and

  1. The greenGain project - Biomass from landscape conservation and maintenance work for renewable energy production in the EU

    Science.gov (United States)

    Clalüna, Aline; Baumgarten, Wibke; García Galindo, Daniel; Lenz, Klaus; Doležal, Jan; De Filippi, Federico; Lorenzo, Joaquín; Montagnoli, Louis

    2017-04-01

    The project greenGain is looking for solutions to increase the energy production with regional and local biomass from landscape conservation and maintenance work, which is performed in the public interest. The relevant resources analysed in the greenGain model regions are, among others, biomass residues from clearing invasive vegetation in marginal agricultural lands in Spain, and residues from abandoned vineyards and olive groves in landscape protected areas in Italy. The main target groups are regional and local players who are responsible for maintenance and conservation work and for the biomass residue management in their regions. Moreover, the focus will be on service providers - including farmers and forest owners, their associations, NGOs, energy providers and consumers. Local companies, municipalities and public authorities are collaborating to identify the still underutilised non-food biomass resources and to discuss the way to integrate them into the local and regional biomass markets. Since the start of the three year project in January 2015, the partners from Italy, Spain, Czech Republic and Germany analysed, among other, the biomass feedstock potential coming from landscape maintenance work, and assessed various technological options to utilise this type of biomass. Further, political, legal and environmental aspects as well as awareness raising and public acceptance actions regarding the energetic use of biomass from public areas were assessed. greenGain also facilitates the exchange between model regions and other similar relevant players in the EU and shares examples of good practice. General guidelines will be prepared to guarantee a wide dissemination to other regions in the EU. Thus, the project shows how to build-up reliable knowledge on local availability of this feedstock and provides know-how concerning planning, harvesting, pre-treatment, storage and sustainable conversion pathways to a wide range of stakeholders in the EU.

  2. The energy landscapes of repeat-containing proteins: topology, cooperativity, and the folding funnels of one-dimensional architectures.

    Directory of Open Access Journals (Sweden)

    Diego U Ferreiro

    2008-05-01

    Full Text Available Repeat-proteins are made up of near repetitions of 20- to 40-amino acid stretches. These polypeptides usually fold up into non-globular, elongated architectures that are stabilized by the interactions within each repeat and those between adjacent repeats, but that lack contacts between residues distant in sequence. The inherent symmetries both in primary sequence and three-dimensional structure are reflected in a folding landscape that may be analyzed as a quasi-one-dimensional problem. We present a general description of repeat-protein energy landscapes based on a formal Ising-like treatment of the elementary interaction energetics in and between foldons, whose collective ensemble are treated as spin variables. The overall folding properties of a complete "domain" (the stability and cooperativity of the repeating array can be derived from this microscopic description. The one-dimensional nature of the model implies there are simple relations for the experimental observables: folding free-energy (DeltaG(water and the cooperativity of denaturation (m-value, which do not ordinarily apply for globular proteins. We show how the parameters for the "coarse-grained" description in terms of foldon spin variables can be extracted from more detailed folding simulations on perfectly funneled landscapes. To illustrate the ideas, we present a case-study of a family of tetratricopeptide (TPR repeat proteins and quantitatively relate the results to the experimentally observed folding transitions. Based on the dramatic effect that single point mutations exert on the experimentally observed folding behavior, we speculate that natural repeat proteins are "poised" at particular ratios of inter- and intra-element interaction energetics that allow them to readily undergo structural transitions in physiologically relevant conditions, which may be intrinsically related to their biological functions.

  3. Probing the potential energy landscape for dissociation of protonated indole via threshold collision-induced dissociation and theoretical studies

    Science.gov (United States)

    Yang, Zhibo; Ruan, Chunhai; Ahmed, H.; Rodgers, M. T.

    2007-09-01

    Collision-induced dissociation of protonated indole with Xe is studied as a function of kinetic energy using guided ion beam tandem mass spectrometry techniques. Activated dissociation resulting in endothermic loss of neutral HCN (or HNC) is the only pathway observed over the range of collision energies examined. The cross-section threshold for this activated dissociation pathway is interpreted to yield 0 and 298 K activation energies for this process after accounting for the effects of multiple ion-neutral collisions, the internal energy distribution of the protonated indole cations, and their lifetimes for dissociation. Density functional theory (DFT) calculations at the MPW1PW91/6-31G* level of theory are used to determine the structures of indole, the protonated indole tautomers, and the transition states, intermediates, and products involved in the activated dissociation of protonated indole. Four distinct pathways between the reactant ion and dissociation products are computed. In all cases, the ionic product formed is C6H5CH2+, while the neutral product is HCN in three of the pathways and HNC in the fourth. The vibrational frequencies and rotational constants of the ground state tautomer of protonated indole and the rate-determining transition state along each of the pathways computed are used for the thermodynamic analysis of the experimental data. The theoretical activation energies and potential energy landscapes for activated dissociation of protonated indole are determined from single point calculations at the MPW1PW91/6-311+G(2d,2p) and MP2(full)/6-311+G(2d,2p) levels of theory, using the MPW1PW91/6-31G* optimized geometries. Both theories produce similar potential energy landscapes for elimination of HCN (or HNC) from protonated indole. Theory suggests that elimination of HNC is favored over HCN. However, our threshold measurements probe the lowest-energy pathway available and are in much better agreement with the higher-energy HCN elimination

  4. Energy Extraction from a Slider-Crank Wave Energy under Irregular Wave Conditions: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Sang, Yuanrui; Karayaka, H. Bora; Yan, Yanjun; Zhang, James Z.; Muljadi, Eduard; Yu, Yi-Hsiang

    2015-08-24

    A slider-crank wave energy converter (WEC) is a novel energy conversion device. It converts wave energy into electricity at a relatively high efficiency, and it features a simple structure. Past analysis on this particular WEC has been done under regular sinusoidal wave conditions, and suboptimal energy could be achieved. This paper presents the analysis of the system under irregular wave conditions; a time-domain hydrodynamics model is adopted and a rule-based control methodology is introduced to better serve the irregular wave conditions. Results from the simulations show that the performance of the system under irregular wave conditions is different from that under regular sinusoidal wave conditions, but a reasonable amount of energy can still be extracted.

  5. Explaining geographic gradients in winter selection of landscapes by boreal caribou with implications under global changes in Eastern Canada.

    Directory of Open Access Journals (Sweden)

    Julien Beguin

    Full Text Available Many animal species exhibit broad-scale latitudinal or longitudinal gradients in their response to biotic and abiotic components of their habitat. Although knowing the underlying mechanism of these patterns can be critical to the development of sound measures for the preservation or recovery of endangered species, few studies have yet identified which processes drive the existence of geographical gradients in habitat selection. Using extensive spatial data of broad latitudinal and longitudinal extent, we tested three hypotheses that could explain the presence of geographical gradients in landscape selection of the endangered boreal woodland caribou (Rangifer tarandus caribou during winter in Eastern Canadian boreal forests: 1 climate-driven selection, which postulates that geographic gradients are surrogates for climatic gradients; 2 road-driven selection, which proposes that boreal caribou adjust their selection for certain habitat classes as a function of proximity to roads; and 3 an additive effect of both roads and climate. Our data strongly supported road-driven selection over climate influences. Thus, direct human alteration of landscapes drives boreal caribou distribution and should likely remain so until the climate changes sufficiently from present conditions. Boreal caribou avoided logged areas two-fold more strongly than burnt areas. Limiting the spread of road networks and accounting for the uneven impact of logging compared to wildfire should therefore be integral parts of any habitat management plan and conservation measures within the range of the endangered boreal caribou. The use of hierarchical spatial models allowed us to explore the distribution of spatially-structured errors in our models, which in turn provided valuable insights for generating alternative hypotheses about processes responsible for boreal caribou distribution.

  6. Conservation of northern bobwhite on private lands in Georgia, USA under uncertainty about landscape-level habitat effects

    Science.gov (United States)

    Howell, J.E.; Moore, C.T.; Conroy, M.J.; Hamrick, R.G.; Cooper, R.J.; Thackston, R.E.; Carroll, J.P.

    2009-01-01

    Large-scale habitat enhancement programs for birds are becoming more widespread, however, most lack monitoring to resolve uncertainties and enhance program impact over time. Georgia?s Bobwhite Quail Initiative (BQI) is a competitive, proposal-based system that provides incentives to landowners to establish habitat for northern bobwhites (Colinus virginianus). Using data from monitoring conducted in the program?s first years (1999?2001), we developed alternative hierarchical models to predict bobwhite abundance in response to program habitat modifications on local and regional scales. Effects of habitat and habitat management on bobwhite population response varied among geographical scales, but high measurement variability rendered the specific nature of these scaled effects equivocal. Under some models, BQI had positive impact at both local farm scales (1, 9 km2), particularly when practice acres were clustered, whereas other credible models indicated that bird response did not depend on spatial arrangement of practices. Thus, uncertainty about landscape-level effects of management presents a challenge to program managers who must decide which proposals to accept. We demonstrate that optimal selection decisions can be made despite this uncertainty and that uncertainty can be reduced over time, with consequent improvement in management efficacy. However, such an adaptive approach to BQI program implementation would require the reestablishment of monitoring of bobwhite abundance, an effort for which funding was discontinued in 2002. For landscape-level conservation programs generally, our approach demonstrates the value in assessing multiple scales of impact of habitat modification programs, and it reveals the utility of addressing management uncertainty through multiple decision models and system monitoring.

  7. Tailoring the Energy Landscape in Quasi-2D Halide Perovskites Enables Efficient Green-Light Emission

    KAUST Repository

    Quan, Li Na

    2017-05-10

    Organo-metal halide perovskites are a promising platform for optoelectronic applications in view of their excellent charge-transport and bandgap tunability. However, their low photoluminescence quantum efficiencies, especially in low-excitation regimes, limit their efficiency for light emission. Consequently, perovskite light-emitting devices are operated under high injection, a regime under which the materials have so far been unstable. Here we show that, by concentrating photoexcited states into a small subpopulation of radiative domains, one can achieve a high quantum yield, even at low excitation intensities. We tailor the composition of quasi-2D perovskites to direct the energy transfer into the lowest-bandgap minority phase and to do so faster than it is lost to nonradiative centers. The new material exhibits 60% photoluminescence quantum yield at excitation intensities as low as 1.8 mW/cm2, yielding a ratio of quantum yield to excitation intensity of 0.3 cm2/mW; this represents a decrease of 2 orders of magnitude in the excitation power required to reach high efficiency compared with the best prior reports. Using this strategy, we report light-emitting diodes with external quantum efficiencies of 7.4% and a high luminescence of 8400 cd/m2.

  8. Tailoring the Energy Landscape in Quasi-2D Halide Perovskites Enables Efficient Green-Light Emission.

    Science.gov (United States)

    Quan, Li Na; Zhao, Yongbiao; García de Arquer, F Pelayo; Sabatini, Randy; Walters, Grant; Voznyy, Oleksandr; Comin, Riccardo; Li, Yiying; Fan, James Z; Tan, Hairen; Pan, Jun; Yuan, Mingjian; Bakr, Osman M; Lu, Zhenghong; Kim, Dong Ha; Sargent, Edward H

    2017-06-14

    Organo-metal halide perovskites are a promising platform for optoelectronic applications in view of their excellent charge-transport and bandgap tunability. However, their low photoluminescence quantum efficiencies, especially in low-excitation regimes, limit their efficiency for light emission. Consequently, perovskite light-emitting devices are operated under high injection, a regime under which the materials have so far been unstable. Here we show that, by concentrating photoexcited states into a small subpopulation of radiative domains, one can achieve a high quantum yield, even at low excitation intensities. We tailor the composition of quasi-2D perovskites to direct the energy transfer into the lowest-bandgap minority phase and to do so faster than it is lost to nonradiative centers. The new material exhibits 60% photoluminescence quantum yield at excitation intensities as low as 1.8 mW/cm 2 , yielding a ratio of quantum yield to excitation intensity of 0.3 cm 2 /mW; this represents a decrease of 2 orders of magnitude in the excitation power required to reach high efficiency compared with the best prior reports. Using this strategy, we report light-emitting diodes with external quantum efficiencies of 7.4% and a high luminescence of 8400 cd/m 2 .

  9. The Swiss Energy Sector. Innovation landscape and chances for the Netherlands; De Zwitserse energiesector. Innovatielandschap en kansen voor Nederland

    Energy Technology Data Exchange (ETDEWEB)

    Van Ewijk, S. [Innovatie Attache Netwerk, Ambassad Berlijn, Berlin (Netherlands)

    2012-08-15

    An overview is given of innovation in the Swiss energy sector and the following research question will be answered: what are the characteristics of the Swiss innovation landscape in the energy sector and what opportunities are there for the Dutch energy sector? The emphasis is on themes that occur in the Dutch top sector policy, such as natural gas and energy conservation. The aim is to encourage cooperation between the Netherlands and Switzerland in the field of energy and provide inspiration for investment, policy solutions and markets in the field of energy. Each chapter contains references to Swiss authorities for more information and further steps [Dutch] Een overzicht wordt gegeven van innovatie in de Zwitserse energiesector en probeert de volgende onderzoeksvraag te beantwoorden: wat zijn de kenmerken van het Zwitserse innovatielandschap in de energiesector en welke kansen zijn er voor de Nederlandse energiesector? De nadruk ligt daarbij op thema's die ook in het Nederlandse topsectorbeleid voorkomen, zoals aardgas en energiebesparing. Het doel is om de samenwerking tussen Nederland en Zwitserland op energiegebied te stimuleren en informatie te bieden als inspiratie voor investeringen, beleidsoplossingen en afzetmarkten op energiegebied. Ieder hoofdstuk bevat verwijzingen naar Zwitserse instanties voor meer informatie en verdere stappen.

  10. LandscapeDNDC used to model nitrous oxide emissions from soils under an oak forest in southern England

    Science.gov (United States)

    Cade, Shirley; Clemitshaw, Kevin; Lowry, David; Yamulki, Sirwan; Casella, Eric; Molina, Saul; Haas, Edwin; Kiese, Ralf

    2013-04-01

    Nitrous oxide (N2O) is an important greenhouse gas, having a global warming potential of approximately 300 times that of carbon dioxide (CO2), and plays a significant role in depleting stratospheric ozone. Its principal source is microbial activity in soils and waters. Measured values of N2O emissions from soils show high temporal dynamics and a large range as a result of inter-related physico-chemical factors affecting the microbial processes, thus making predictions difficult. Emissions often occur in pulses following re-wetting, frost-thaw or management events such as N-fertilization, which further complicates predictions. Process-based models have been developed to help understand this emission variability and as potential tools for IPCC Tier 3 reporting on national emission inventories. Forests are promoted as sinks for CO2 and can be used as renewable sources of energy or longer term CO2 storage if timber is used in products such as in construction and furniture, provided appropriate replanting takes place. It is important that the effect of any changes in forest management and land use as a result of a desire to reduce CO2 emissions does not increase N2O emissions from forest soils, which are still poorly understood, compared to agricultural soils. LandscapeDNDC (Haas et al 2012) has been developed as a process-oriented model, based on the biogeochemical model, DNDC (Li et al, 1992), in order to simulate biosphere-atmosphere-hydrosphere exchanges at site and regional scales. It can model the carbon and nitrogen turnover and associated greenhouse gas (GHG) emissions of forest, agricultural and grassland ecosystems, and allows modelling of impacts of regional land use change over time. This study uses data (including forest growth, GHG emissions and soil moisture) from an oak forest, known as the Straits Enclosure, at Alice Holt in Hampshire, where extensive measurements have been made by Forest Research since 1995. It involves validation of the site scale

  11. Fish energy budget under ocean warming and flame retardant exposure.

    Science.gov (United States)

    Anacleto, Patrícia; Figueiredo, Cátia; Baptista, Miguel; Maulvault, Ana Luísa; Camacho, Carolina; Pousão-Ferreira, Pedro; Valente, Luísa M P; Marques, António; Rosa, Rui

    2018-02-28

    Climate change and chemical contamination are global environmental threats of growing concern for the scientific community and regulatory authorities. Yet, the impacts and interactions of both stressors (particularly ocean warming and emerging chemical contaminants) on physiological responses of marine organisms remain unclear and still require further understanding. Within this context, the main goal of this study was to assess, for the first time, the effects of warming (+ 5 °C) and accumulation of a polybrominated diphenyl ether congener (BDE-209, brominated flame retardant) through dietary exposure on energy budget of the juvenile white seabream (Diplodus sargus). Specifically, growth (G), routine metabolism (R), excretion (faecal, F and nitrogenous losses, U) and food consumption (C) were calculated to obtain the energy budget. The results demonstrated that the energy proportion spent for G dominated the mode of the energy allocation of juvenile white seabream (56.0-67.8%), especially under the combined effect of warming plus BDE-209 exposure. Under all treatments, the energy channelled for R varied around 26% and a much smaller percentage was channelled for excretion (F: 4.3-16.0% and U: 2.3-3.3%). An opposite trend to G was observed to F, where the highest percentage (16.0 ± 0.9%) was found under control temperature and BDE-209 exposure via diet. In general, the parameters were significantly affected by increased temperature and flame retardant exposure, where higher levels occurred for: i) wet weight, relative growth rate, protein and ash contents under warming conditions, ii) only for O:N ratio under BDE-209 exposure via diet, and iii) for feed efficiency, ammonia excretion rate, routine metabolic rate and assimilation efficiency under the combination of both stressors. On the other hand, decreased viscerosomatic index was observed under warming and lower fat content was observed under the combined effect of both stressors. Overall, under future

  12. The importance of on-site evaluation for placing renewable energy in the landscape: A case study of the Búrfell wind farm (Iceland

    Directory of Open Access Journals (Sweden)

    Frantál Bohumil

    2017-12-01

    Full Text Available Using a case study of the Búrfell wind farm project, a large wind farm proposed in the Central Highlands of Iceland, the authors attempt to provide new insights into the factors shaping subjective landscape perceptions and attitudes to renewable energy developments, and into alternative methods that may be used for their assessment. The research was based on an on-site visit and actual experience of the place, investigated using a combination of mental mapping, the technique of the semantic differential and a questionnaire survey. The results show that participants visiting a landscape and using all sensory organs in combination with mental mapping, can reveal more important information than using only ‘laboratory’ methods with static photographs. The results suggest that the perception of landscape is highly subjective. Those perceiving the landscape as more open, homogenous, industrial, unfamiliar and resilient also consider it more compatible with wind turbines. The perception of the landscape’s compatibility with wind turbines proved to be a dominant factor shaping attitudes towards the project. The acceptance of wind turbines is not, however, inconsistent with the perception of landscape as beautiful, wild and unique. Participants from more densely populated countries and countries with a developed wind energy industry were more tolerant of wind turbines in the Icelandic landscape.

  13. Untangling human development and natural gradients: implications of underlying correlation structure for linking landscapes and riverine ecosystems

    Science.gov (United States)

    Yasmin Lucero; E. Ashley Steel; Kelly M. Burnett; Kelly. Christiansen

    2011-01-01

    Increasingly, ecologists seek to identify and quantify relationships between landscape gradients and aquatic ecosystems. Considerable statistical challenges emerge in this effort, some of which are attributable to multicollinearity between human development and landscape gradients. In this paper, we measure the covariation between human development—such as agriculture...

  14. Dynamics of a temperate deciduous forest under landscape-scale management: Implications for adaptability to climate change

    Science.gov (United States)

    Matthew G. Olson; Benjamin O. Knapp; John M. Kabrick

    2017-01-01

    Landscape forest management is an approach to meeting diverse objectives that collectively span multiple spatial scales. It is critical that we understand the long-term effects of landscape management on the structure and composition of forest tree communities to ensure that these practices are sustainable. Furthermore, it is increasingly important to also consider...

  15. Dynamics of carbon, water and energy cycles in a heterogeneous landscape and a changing climate

    Science.gov (United States)

    Schmidt, A.; Law, B. E.; Still, C. J.; Hilker, T.

    2016-12-01

    The combined effects of changes in land-use and land cover (LULC) and climate on carbon and water cycling need to be assessed at regional scales. LULC changes over time have many drivers such as expanding urban areas, exploration of new agricultural areas due to overused natural resources of current agricultural areas (e.g. degraded soil), economical reasons, or policy changes that encourage the use of alternative energy resources. Our study assesses the effects of conversion of semi-arid sagebrush and agricultural crops to bioenergy production on carbon, water and energy cycling, and resulting heating or cooling effects. Our project focusses on Oregon, where agricultural crops, significant forest area, and urban expansion are coupled with a strong spatial climate gradient that allows us to examine influences on carbon sequestration by the terrestrial biosphere. Our inverse modeling results showed that the prior fluxes modelled with CLM4.5 underestimated NEE in the highly productive western Douglas fir forests by more than 50%. Based on the results of our Bayesian inversion, we optimized ecosystem fluxes and changed CLM model parameters accordingly. By integrating remote sensing LULC data, eddy covariance data from flux sites, tall tower CO2 observations, biomass estimates from field samples, and CLM4.5, we predict current and future statewide carbon sequestration with unprecedented accuracy. Using inventories and tower flux data, we determined the effect of conversion of hay and grass seed cropland (323,200 ha) to hybrid poplar and found the state NEP increased from 4 TgCO2 per year to 13 TgCO2 per year for that area. The last coal power plant in the state (Boardman) is in the process of switching from coal combustion to biofuel burning to meet the state's goal for the reduction of greenhouse gas emissions. Our results show that the 7816 tons of biomass per day to keep the 518 MW power plant running at base load would amount to 35,000 hectares of hybrid poplar per

  16. Prospects for nuclear energy in Kenya under vision 2030

    International Nuclear Information System (INIS)

    Shadrack, A. K.

    2012-01-01

    Overcoming energy poverty is one of Kenya's greatest challenges. Majority of Kenyans currently have no access to modern energy services and technologies. The challenge is thus to find appropriate and reliable solutions for providing energy sources for social and economic development. This study intends to focus on the development of nuclear power technology under the Kenya 2030 vision. This research project intends to investigate the advancement stages that Kenya has undertaken towards the implementation of nuclear power plants. A background review of nuclear energy in Kenya, and nuclear environments, have been reviewed and projected through the 2030 vision. The study will provide a useful starting point for policy makers interested in the state of the ecosystem

  17. Hierarchical structure of the energy landscape of proteins revisited by time series analysis. II. Investigation of explicit solvent effects

    Science.gov (United States)

    Alakent, Burak; Camurdan, Mehmet C.; Doruker, Pemra

    2005-10-01

    Time series analysis tools are employed on the principal modes obtained from the Cα trajectories from two independent molecular-dynamics simulations of α-amylase inhibitor (tendamistat). Fluctuations inside an energy minimum (intraminimum motions), transitions between minima (interminimum motions), and relaxations in different hierarchical energy levels are investigated and compared with those encountered in vacuum by using different sampling window sizes and intervals. The low-frequency low-indexed mode relationship, established in vacuum, is also encountered in water, which shows the reliability of the important dynamics information offered by principal components analysis in water. It has been shown that examining a short data collection period (100ps) may result in a high population of overdamped modes, while some of the low-frequency oscillations (memory: future conformations are less dependent on previous conformations due to the lowering of energy barriers in hierarchical levels of the energy landscape. In short-time dynamics (sight contradicts. However, this comes about because water enhances the transitions between minima and forces the protein to reduce its already inherent inability to maintain oscillations observed in vacuum. Some of the frequencies lower than 10cm-1 are found to be overdamped, while those higher than 20cm-1 are slightly increased. As for the long-time dynamics in water, it is found that random-walk motion is maintained for approximately 200ps (about five times of that in vacuum) in the low-indexed modes, showing the lowering of energy barriers between the higher-level minima.

  18. Under-Use of Body Energy and Over-Use of External Energy

    DEFF Research Database (Denmark)

    Nørgaard, Jørgen

    2005-01-01

    by overeating and under-use of the body energy, due to increased use of mechanized and energy consuming assistance for transport and other daily tasks. This connects to the other problem, namely these countries’ excessive use of fossil fuels and other environmentally harmful forms of nature’s external energy....... This paper illuminates the options for integrated solutions to the two problems by making more use of body energy as a means to reduce the use of nature’s external energy. First is listed a human’s body energy used for various tasks and occupations, showing that a person’s use of external energy is and order......, achieved by healthy extra human efforts. Also, the paper will suggest ways to integrate energy saving policies with health policies for organizing and designing cities and houses to be “healthy inconvenient”, encouraging or pushing people to use their body in their daily doings. This is an enormous...

  19. Aggregation of energy and water surface fluxes at the agricultural landscape scale by combining scintillometer measurements, remote sensing data and SVAT modelling.

    Science.gov (United States)

    Brut, A.; Rivalland, V.; Coudert, B.; Solignac, P. A.; Cote, J.; Keravec, P.; Merlin, O.; Ceschia, E.

    2012-04-01

    The Earth's surface shows variability at the landscape scale (1-10 km) and this has consequences on the water and energy surface fluxes intensity and spatial distribution. In this context, the question of the measurement representativeness is posed. Similarly, the simulation of these surface fluxes is depending on the models parameters distribution whether they are considered at the crop scale or the landscape scale. The purpose of this work is to present a study combining 1) measurements from an eXtra Large Aperture Scintillometer (XLAS), 2) simulations with a calibrated Soil-Vegetation-Atmosphere-Transfer (SVAT) model and 3) fluxes estimates based on a simple Equation Balance model and high resolution remote sensing data, in order to better understand the aggregation processes of surface energy fluxes over agricultural landscapes. In the framework of the SudOuest project managed by CESBIO and the CarboEurope Regional Experiment (CERES 2007), a comprehensive instrumental set-up has been installed over an agricultural area in Southwestern France, near Toulouse. It included an optical scintillometer integrating sensible heat flux over a 10 km transect, between June and September 2007; and two instrumented sites which are part of the GHGEurope network. On these sites, micrometeorological (mass and energy fluxes), vegetation and other biophysical parameters are continuously collected since the year 2005. In this study, we first present the flux computation and data validation from the XLAS measurements, and we perform a quick analysis of the surface heat fluxes related to both the landscape and the local flux datasets from local instrumented fields. Then, a two energy sources SVAT model (SEtHyS french acronym for sol moisture monitoring) has been calibrated over the 2 agricultural experimental sites for the main classes of vegetation and soil types of the studied area. Different aggregation configurations have been tested with the simulated fluxes, either using a

  20. Energy conservation, energy efficiency and energy savings regulatory hypotheses - taxation, subsidies and underlying economics

    Energy Technology Data Exchange (ETDEWEB)

    Trumpy, T. [International Legal Counsel, Brussels (Belgium)

    1995-12-01

    More efficient use of energy resources can be promoted by various regulatory means, i.e., taxation, subsidies, and pricing. Various incentives can be provided by income and revenue tax breaks-deductible energy audit fees, energy saving investment credits, breaks for energy saving entrepreneurs, and energy savings accounts run through utility accounts. Value added and excise taxes can also be adjusted to reward energy saving investments and energy saving entrepreneurial activity. Incentives can be provided in the form of cash refunds, including trade-in-and-scrap programs and reimbursements or subsidies on audit costs and liability insurance. Pricing incentives include lower rates for less energy use, prepayment of deposit related to peak load use, electronically dispatched multiple tariffs, savings credits based on prior peak use, and subsidized {open_quotes}leasing{close_quotes} of more efficient appliances and lights. Credits, with an emphasis on pooling small loans, and 5-year energy savings contracts are also discussed.

  1. Energy Expenditure of Trotting Gait Under Different Gait Parameters

    Science.gov (United States)

    Chen, Xian-Bao; Gao, Feng

    2017-07-01

    Robots driven by batteries are clean, quiet, and can work indoors or in space. However, the battery endurance is a great problem. A new gait parameter design energy saving strategy to extend the working hours of the quadruped robot is proposed. A dynamic model of the robot is established to estimate and analyze the energy expenditures during trotting. Given a trotting speed, optimal stride frequency and stride length can minimize the energy expenditure. However, the relationship between the speed and the optimal gait parameters is nonlinear, which is difficult for practical application. Therefore, a simplified gait parameter design method for energy saving is proposed. A critical trotting speed of the quadruped robot is found and can be used to decide the gait parameters. When the robot is travelling lower than this speed, it is better to keep a constant stride length and change the cycle period. When the robot is travelling higher than this speed, it is better to keep a constant cycle period and change the stride length. Simulations and experiments on the quadruped robot show that by using the proposed gait parameter design approach, the energy expenditure can be reduced by about 54% compared with the 100 mm stride length under 500 mm/s speed. In general, an energy expenditure model based on the gait parameter of the quadruped robot is built and the trotting gait parameters design approach for energy saving is proposed.

  2. Take-or-Pay under Japanese energy policy

    International Nuclear Information System (INIS)

    Namikawa, Ryoichi

    2003-01-01

    Japan has tried to increase the import of liquefied natural gas (LNG) because of the nation's fragile energy supply structure. In Japan, almost all LNG is imported under long-term contracts with a Take-or-Pay clause, although buyers assume considerable risk under such a clause. This paper tries to determine why the Take-or-Pay clause has been retained in LNG import contracts in Japan, focusing on the relation between Take-or-Pay and energy security policy. It is found that the government has not pursued a consistent, consecutive policy on Take-or-Pay under the changing energy situation after oil crises. On the one hand, the government has accepted Take-or-Pay because it secures a stable supply of LNG, but on the other hand, it has tried to scrap Take-or-Pay in order to reduce buyers' risk. Furthermore, it was not until the middle/late 1990s that the government implemented deregulation. It is concluded that the government's energy security policy has played an important role in keeping Take-or-Pay in Japan

  3. Curl flux, coherence, and population landscape of molecular systems: Nonequilibrium quantum steady state, energy (charge) transport, and thermodynamics

    International Nuclear Information System (INIS)

    Zhang, Z. D.; Wang, J.

    2014-01-01

    We established a theoretical framework in terms of the curl flux, population landscape, and coherence for non-equilibrium quantum systems at steady state, through exploring the energy and charge transport in molecular processes. The curl quantum flux plays the key role in determining transport properties and the system reaches equilibrium when flux vanishes. The novel curl quantum flux reflects the degree of non-equilibriumness and the time-irreversibility. We found an analytical expression for the quantum flux and its relationship to the environmental pumping (non-equilibriumness quantified by the voltage away from the equilibrium) and the quantum tunneling. Furthermore, we investigated another quantum signature, the coherence, quantitatively measured by the non-zero off diagonal element of the density matrix. Populations of states give the probabilities of individual states and therefore quantify the population landscape. Both curl flux and coherence depend on steady state population landscape. Besides the environment-assistance which can give dramatic enhancement of coherence and quantum flux with high voltage at a fixed tunneling strength, the quantum flux is promoted by the coherence in the regime of small tunneling while reduced by the coherence in the regime of large tunneling, due to the non-monotonic relationship between the coherence and tunneling. This is in contrast to the previously found linear relationship. For the systems coupled to bosonic (photonic and phononic) reservoirs the flux is significantly promoted at large voltage while for fermionic (electronic) reservoirs the flux reaches a saturation after a significant enhancement at large voltage due to the Pauli exclusion principle. In view of the system as a quantum heat engine, we studied the non-equilibrium thermodynamics and established the analytical connections of curl quantum flux to the transport quantities such as energy (charge) transfer efficiency, chemical reaction efficiency, energy

  4. Free energy landscape of dissociative adsorption of methane on ideal and defected graphene from ab initio simulations

    Science.gov (United States)

    Wlazło, M.; Majewski, J. A.

    2018-03-01

    We study the dissociative adsorption of methane at the surface of graphene. Free energy profiles, which include activation energies for different steps of the reaction, are computed from constrained ab initio molecular dynamics. At 300 K, the reaction barriers are much lower than experimental bond dissociation energies of gaseous methane, strongly indicating that the graphene surface acts as a catalyst of methane decomposition. On the other hand, the barriers are still much higher than on the nickel surface. Methane dissociation therefore occurs at a higher rate on nickel than on graphene. This reaction is a prerequisite for graphene growth from a precursor gas. Thus, the growth of the first monolayer should be a fast and efficient process while subsequent layers grow at a diminished rate and in a more controllable manner. Defects may also influence reaction energetics. This is evident from our results, in which simple defects (Stone-Wales defect and nitrogen substitution) lead to different free energy landscapes at both dissociation and adsorption steps of the process.

  5. Energy landscape of the finite-size mean-field 2-spin spherical model and topology trivialization.

    Science.gov (United States)

    Mehta, Dhagash; Hauenstein, Jonathan D; Niemerg, Matthew; Simm, Nicholas J; Stariolo, Daniel A

    2015-02-01

    Motivated by the recently observed phenomenon of topology trivialization of potential energy landscapes (PELs) for several statistical mechanics models, we perform a numerical study of the finite-size 2-spin spherical model using both numerical polynomial homotopy continuation and a reformulation via non-Hermitian matrices. The continuation approach computes all of the complex stationary points of this model while the matrix approach computes the real stationary points. Using these methods, we compute the average number of stationary points while changing the topology of the PEL as well as the variance. Histograms of these stationary points are presented along with an analysis regarding the complex stationary points. This work connects topology trivialization to two different branches of mathematics: algebraic geometry and catastrophe theory, which is fertile ground for further interdisciplinary research.

  6. Integration of ecological and thermodynamic concepts in the design of sustainable energy landscapes

    NARCIS (Netherlands)

    Stremke, S.; Koh, J.

    2011-01-01

    Resource depletion and climate change motivate a transition to sustainable energy systems that make effective use of renewable sources. Whereas nature presents strategies to sustain on the basis of renewables, the Laws of Thermodynamics can help to increase efficiency in energy use. In previous

  7. Efficient sampling over rough energy landscapes with high barriers: A combination of metadynamics with integrated tempering sampling

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y. Isaac [Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Zhang, Jun; Che, Xing; Yang, Lijiang; Gao, Yi Qin, E-mail: gaoyq@pku.edu.cn [Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Biodynamic Optical Imaging Center, Peking University, Beijing 100871 (China)

    2016-03-07

    In order to efficiently overcome high free energy barriers embedded in a complex energy landscape and calculate overall thermodynamics properties using molecular dynamics simulations, we developed and implemented a sampling strategy by combining the metadynamics with (selective) integrated tempering sampling (ITS/SITS) method. The dominant local minima on the potential energy surface (PES) are partially exalted by accumulating history-dependent potentials as in metadynamics, and the sampling over the entire PES is further enhanced by ITS/SITS. With this hybrid method, the simulated system can be rapidly driven across the dominant barrier along selected collective coordinates. Then, ITS/SITS ensures a fast convergence of the sampling over the entire PES and an efficient calculation of the overall thermodynamic properties of the simulation system. To test the accuracy and efficiency of this method, we first benchmarked this method in the calculation of ϕ − ψ distribution of alanine dipeptide in explicit solvent. We further applied it to examine the design of template molecules for aromatic meta-C—H activation in solutions and investigate solution conformations of the nonapeptide Bradykinin involving slow cis-trans isomerizations of three proline residues.

  8. Complex-network analysis of combinatorial spaces: the NK landscape case.

    Science.gov (United States)

    Tomassini, Marco; Vérel, Sébastien; Ochoa, Gabriela

    2008-12-01

    We propose a network characterization of combinatorial fitness landscapes by adapting the notion of inherent networks proposed for energy surfaces. We use the well-known family of NK landscapes as an example. In our case the inherent network is the graph whose vertices represent the local maxima in the landscape, and the edges account for the transition probabilities between their corresponding basins of attraction. We exhaustively extracted such networks on representative NK landscape instances, and performed a statistical characterization of their properties. We found that most of these network properties are related to the search difficulty on the underlying NK landscapes with varying values of K .

  9. Landscape transformation

    OpenAIRE

    Koželj, Urša

    2014-01-01

    In my work, titled Landscape transformation, in the first theoretical-art part, I focus on a landscape painting style in fifteen exposed works, done by different authors. While analyzing depictions of the landscape I establish how the development of photography has in any way affected the transformation of the landscape. In the practical part I describe my work, soft ground graphics with the motive of the landscape, mountain landscape and caves. I devoted the last chapter of my thesis to the ...

  10. Landscape Studio

    DEFF Research Database (Denmark)

    Hansen, Peter Lundsgaard

    2017-01-01

    Landscape studio documents is the biography of the method 'design conversation' and contributes to the way we work with landscapes. The blog communicates renewed landscape didactics and leads to the innovation of design practices.......Landscape studio documents is the biography of the method 'design conversation' and contributes to the way we work with landscapes. The blog communicates renewed landscape didactics and leads to the innovation of design practices....

  11. Cellular network entropy as the energy potential in Waddington's differentiation landscape

    Science.gov (United States)

    Banerji, Christopher R. S.; Miranda-Saavedra, Diego; Severini, Simone; Widschwendter, Martin; Enver, Tariq; Zhou, Joseph X.; Teschendorff, Andrew E.

    2013-01-01

    Differentiation is a key cellular process in normal tissue development that is significantly altered in cancer. Although molecular signatures characterising pluripotency and multipotency exist, there is, as yet, no single quantitative mark of a cellular sample's position in the global differentiation hierarchy. Here we adopt a systems view and consider the sample's network entropy, a measure of signaling pathway promiscuity, computable from a sample's genome-wide expression profile. We demonstrate that network entropy provides a quantitative, in-silico, readout of the average undifferentiated state of the profiled cells, recapitulating the known hierarchy of pluripotent, multipotent and differentiated cell types. Network entropy further exhibits dynamic changes in time course differentiation data, and in line with a sample's differentiation stage. In disease, network entropy predicts a higher level of cellular plasticity in cancer stem cell populations compared to ordinary cancer cells. Importantly, network entropy also allows identification of key differentiation pathways. Our results are consistent with the view that pluripotency is a statistical property defined at the cellular population level, correlating with intra-sample heterogeneity, and driven by the degree of signaling promiscuity in cells. In summary, network entropy provides a quantitative measure of a cell's undifferentiated state, defining its elevation in Waddington's landscape. PMID:24154593

  12. Characterizing European cultural landscapes

    DEFF Research Database (Denmark)

    Tieskens, Koen F.; Schulp, Catharina J E; Levers, Christian

    2017-01-01

    Almost all rural areas in Europe have been shaped or altered by humans and can be considered cultural landscapes, many of which now are considered to entail valuable cultural heritage. Current dynamics in land management have put cultural landscapes under a huge pressure of agricultural intensifi......Almost all rural areas in Europe have been shaped or altered by humans and can be considered cultural landscapes, many of which now are considered to entail valuable cultural heritage. Current dynamics in land management have put cultural landscapes under a huge pressure of agricultural...... intensification and land abandonment. To prevent the loss of cultural landscapes, knowledge on the location of different types of cultural landscapes is needed. In this paper, we present a characterization of European cultural landscapes based on the prevalence of three key dimensions of cultural landscapes......: landscape structure, management intensity, and value and meaning. We mapped these dimensions across Europe at a 1-km resolution by combining proxies on management intensity and landscape structure with new indicators such as social media usage and registered traditional food products. We integrated...

  13. Wave Runup on a Frozen Beach Under High Energy Conditions

    Science.gov (United States)

    Didier, D.; Bernatchez, P.; Dumont, D.; Corriveau, M.

    2017-12-01

    High and mid-latitude beaches have typical morphological characteristics influenced by nearshore processes prevailing under ice conditions during cold season. Nearshore ice complexes (NIC) offer a natural coastal protection by covering beach sediments, while offshore ice-infested waters dissipate incoming waves. Climate change contributes to sea ice shrinking therefore reducing its protection against erosion and flooding. In the Estuary and Gulf of the St. Lawrence (ESL, GSL) (eastern Canada), sea ice cover undergoes an overall shrinking and simulated future projections tend toward a negligible effect on wave climate by 2100. Quantifying the effect of nearshore dynamics on frozen beaches is therefore imperative for coastal management as more wave energy at the coast is expected in the future. To measure the effect of a frozen beach on wave runup elevations, this study employs a continuous video recording of the swash motion at 4Hz. Video-derived wave runup statistics have been extracted during a tidal cycle on a frozen beach, using the Pointe-Lebel beach (ESL) as a test case. Timestack analysis was combined with offshore water levels and wave measurements. A comparison of runup under icy conditions (Dec. 30 2016) with a runup distribution during summer was made under similar high energy wave conditions. Results indicate high runup excursions potentially caused by lowered sediment permeability due to high pore-ice saturation in the swash zone, accentuating the overwash of the eroding coastline and thus the risk of flooding. With projected reduction in coastal sea ice cover and thus higher wave energy, this study suggests that episodes of degradation and weakening could influence the coastal flood risk in mid- and high-latitude cold environments.

  14. The multi-state energy landscape of the SAM-I riboswitch: A single-molecule Förster resonance energy transfer spectroscopy study

    Science.gov (United States)

    Manz, Christoph; Kobitski, Andrei Yu.; Samanta, Ayan; Jäschke, Andres; Nienhaus, G. Ulrich

    2018-03-01

    RNA (ribonucleic acid) molecules are highly flexible biopolymers fluctuating at physiological temperatures among many different conformations that are represented by minima in a hierarchical conformational free energy landscape. Here we have employed single-molecule FRET (smFRET) to explore the energy landscape of the B. subtilis yitJ SAM-I riboswitch (RS). In this small RNA molecule, specific binding of an S-adenosyl-L-methionine (SAM) ligand in the aptamer domain regulates gene expression by inducing structural changes in another domain, the expression platform, causing transcription termination by the RNA polymerase. We have measured smFRET histograms over wide ranges of Mg2+ concentration for three RS variants that were specifically labeled with fluorescent dyes on different sites. In the analysis, different conformations are associated with discrete Gaussian model distributions, which are typically fairly broad on the FRET efficiency scale and thus can be extremely challenging to unravel due to their mutual overlap. Our earlier work on two SAM-I RS variants revealed four major conformations. By introducing a global fitting procedure which models both the Mg2+ concentration dependencies of the fractional populations and the average FRET efficiencies of the individual FRET distributions according to Mg2+ binding isotherms, we were able to consistently describe the histogram data of both variants at all studied Mg2+ concentrations. With the third FRET-labeled variant, however, we found significant deviations when applying the four-state model to the data. This can arise because the different FRET labeling of the new variant allows two states to be distinguished that were previously not separable due to overlap. Indeed, the resulting five-state model presented here consistently describes the smFRET histograms of all three variants as well as their variations with Mg2+ concentration. We also performed a triangulation of the donor position for two of the constructs

  15. RAAAF's office landscape The End of Sitting: Energy expenditure and temporary comfort when working in non-sitting postures.

    Science.gov (United States)

    Caljouw, Simone R; de Vries, Rutger; Withagen, Rob

    2017-01-01

    An earlier study suggested that the activity-inviting office landscape called "The End of Sitting", designed by Rietveld Architecture Art Affordances (RAAAF), should be considered as an alternative working environment to prevent sedentary behavior. The End of Sitting lacks chairs and tables but consists instead of a myriad of sloped surfaces at different heights that afford workers to stand, lean or recline at different locations. In this study, we assessed the impact of four of its workspaces on physical intensity, temporary comfort and productivity of office work and compared the outcomes with sitting and standing behind a desk. Twenty-four participants worked for 10 minutes in each of the six test conditions. Energy expenditure, measured by indirect calorimetry, and heart rate were recorded. Questionnaires were used to assess the perceived comfort. The number of words found in the word search test was counted as a measure of productivity. The majority of The End of Sitting workspaces led to a significant increase in energy expenditure compared with sitting behind a desk (ps sitting (1.32 METs) and not significantly different from standing (1.47 METs). The scores on the general comfort scale indicated that some workspaces were less comfortable than sitting (ps Sitting workspaces was equally or more comfortable than sitting. No differences in productivity between the test conditions were found. Further long-term studies are required to assess the behavioral adaptations, productivity and the level of comfort when using The End of Sitting as a permanent office.

  16. America's Changing Energy Landscape - USGS National Coal Resources Data System Changes to National Energy Resources Data System.

    Science.gov (United States)

    East, J. A., II

    2016-12-01

    The U.S. Geological Survey's (USGS) Eastern Energy Resources Science Center (EERSC) has an ongoing project which has mapped coal chemistry and stratigraphy since 1977. Over the years, the USGS has collected various forms of coal data and archived that data into the National Coal Resources Data System (NCRDS) database. NCRDS is a repository that houses data from the major coal basins in the United States and includes information on location, seam thickness, coal rank, geologic age, geographic region, geologic province, coalfield, and characteristics of the coal or lithology for that data point. These data points can be linked to the US Coal Quality Database (COALQUAL) to include ultimate, proximate, major, minor and trace-element data. Although coal is an inexpensive energy provider, the United States has shifted away from coal usage recently and branched out into other forms of non-renewable and renewable energy because of environmental concerns. NCRDS's primary method of data capture has been USGS field work coupled with cooperative agreements with state geological agencies and universities doing coal-related research. These agreements are on competitive five-year cycles that have evolved into larger scope research efforts including solid fuel resources such as coal-bed methane, shale gas and oil. Recently these efforts have expanded to include environmental impacts of the use of fossil fuels, which has allowed the USGS to enter into agreements with states for the Geologic CO2 Storage Resources Assessment as required by the Energy Independence and Security Act. In 2016 they expanded into research areas to include geothermal, conventional and unconventional oil and gas. The NCRDS and COALQUAL databases are now online for the public to use, and are in the process of being updated to include new data for other energy resources. Along with this expansion of scope, the database name will change to the National Energy Resources Data System (NERDS) in FY 2017.

  17. Evapotranspiration and surface energy balance across an agricultural-urban landscape gradient in Southern California, USA.

    Science.gov (United States)

    Shiflett, S. A.; Anderson, R. G.; Jenerette, D.

    2014-12-01

    Urbanization substantially affects energy, surface and air temperature, and hydrology due to extensive modifications in land surface properties such as vegetation, albedo, thermal capacity and soil moisture. The magnitude and direction of these alterations depends heavily on the type of urbanization that occurs. We investigated energy balance variation in a local network of agricultural and urban ecosystems using the eddy covariance method to better understand how vegetation fraction and degree of urbanization affects energy exchanges between the land surface and the atmosphere. We deployed eddy flux systems within a well-irrigated, agricultural citrus orchard, a moderately developed urban zone with a substantial amount of local vegetative cover, and an intensely developed urban zone with minimal vegetative cover and increased impervious surfaces relative to the other two sites. Latent energy (LE) fluxes in the agricultural area ranged from 7.9 ± 1.4 W m-2 (nighttime) to 168.7 ± 6.2 W m-2 (daytime) compared to 10.2 ± 3.5 W m-2 and 40.6 ± 4.1 W m-2, respectively, for the moderately developed urban area. Sensible energy (H) fluxes ranged from -9.1 ± 1.0 W m-2 (nighttime) to 119 ± 7.0 W m-2 (daytime) in the agricultural area compared to 9.6 ± 2.6 W m-2 and 134 ± 6.0 W m-2, respectively, for the moderately developed urban zone. Daytime LE is reduced with increasing urbanization; however, daily cycles of LE are less recognizable in urban areas compared to distinct daily cycles obtained above a mature citrus crop. In contrast, both daytime and nighttime H increases with increasing degree of urbanization. Reduction in vegetation and increases in impervious surfaces along an urbanization gradient leads to alterations in energy balance, which are associated with microclimate and water use changes.

  18. Sub-seasonal thaw slump mass wasting is not consistently energy limited at the landscape scale

    Science.gov (United States)

    Zwieback, Simon; Kokelj, Steven V.; Günther, Frank; Boike, Julia; Grosse, Guido; Hajnsek, Irena

    2018-02-01

    Predicting future thaw slump activity requires a sound understanding of the atmospheric drivers and geomorphic controls on mass wasting across a range of timescales. On sub-seasonal timescales, sparse measurements indicate that mass wasting at active slumps is often limited by the energy available for melting ground ice, but other factors such as rainfall or the formation of an insulating veneer may also be relevant. To study the sub-seasonal drivers, we derive topographic changes from single-pass radar interferometric data acquired by the TanDEM-X satellites. The estimated elevation changes at 12 m resolution complement the commonly observed planimetric retreat rates by providing information on volume losses. Their high vertical precision (around 30 cm), frequent observations (11 days) and large coverage (5000 km2) allow us to track mass wasting as drivers such as the available energy change during the summer of 2015 in two study regions. We find that thaw slumps in the Tuktoyaktuk coastlands, Canada, are not energy limited in June, as they undergo limited mass wasting (height loss of around 0 cm day-1) despite the ample available energy, suggesting the widespread presence of early season insulating snow or debris veneer. Later in summer, height losses generally increase (around 3 cm day-1), but they do so in distinct ways. For many slumps, mass wasting tracks the available energy, a temporal pattern that is also observed at coastal yedoma cliffs on the Bykovsky Peninsula, Russia. However, the other two common temporal trajectories are asynchronous with the available energy, as they track strong precipitation events or show a sudden speed-up in late August respectively. The observed temporal patterns are poorly related to slump characteristics like the headwall height. The contrasting temporal behaviour of nearby thaw slumps highlights the importance of complex local and temporally varying controls on mass wasting.

  19. Charting the energy landscape of metal/organic interfaces via machine learning

    Science.gov (United States)

    Scherbela, Michael; Hörmann, Lukas; Jeindl, Andreas; Obersteiner, Veronika; Hofmann, Oliver T.

    2018-04-01

    The rich polymorphism exhibited by inorganic/organic interfaces is a major challenge for materials design. In this work, we present a method to efficiently explore the potential energy surface and predict the formation energies of polymorphs and defects. This is achieved by training a machine learning model on a list of only 100 candidate structures that are evaluated via dispersion-corrected density functional theory (DFT) calculations. We demonstrate the power of this approach for tetracyanoethylene on Ag(100) and explain the anisotropic ordering that is observed experimentally.

  20. Accounting for asymmetric price responses and underlying energy demand trends in OECD industrial energy demand

    International Nuclear Information System (INIS)

    Adeyemi, Olutomi I.; Hunt, Lester C.

    2014-01-01

    This paper explores the way technical progress and improvements in energy efficiency are captured when modelling OECD industrial energy demand. The industrial sectors of the developed world involve a number of different practices and processes utilising a range of different technologies. Consequently, given the derived demand nature of energy, it is vital when modelling industrial energy demand that the impact of technical progress is appropriately captured. However, the energy economics literature does not give a clear guide on how this can be achieved; one strand suggests that technical progress is ‘endogenous’ via asymmetric price responses whereas another strand suggests that it is ‘exogenous’. More recently, it has been suggested that potentially there is a role for both ‘endogenous’ technical progress and ‘exogenous’ technical progress and consequently the general model should be specified accordingly. This paper therefore attempts to model OECD industrial energy demand using annual time series data over the period 1962–2010 for 15 OECD countries. Using the Structural Time Series Model framework, the general specifications allow for both asymmetric price responses (for technical progress to impact endogenously) and an underlying energy demand trend (for technical progress and other factors to impact exogenously, but in a non-linear way). The results show that almost all of the preferred models for OECD industrial energy demand incorporate both a stochastic underlying energy demand trend and asymmetric price responses. This gives estimated long-run income elasticities in the range of 0.34 to 0.96; estimated long-run price-maximum elasticities in the range of − 0.06 to − 1.22; estimated long-run price-recovery elasticities in the range of 0.00 to − 0.27; and estimated long-run price-cut elasticities in the range of 0.00 to − 0.18. Furthermore, the analysis suggests that when modelling industrial energy demand there is a place for

  1. Potential energy landscape signatures of slow dynamics in glass forming liquids

    DEFF Research Database (Denmark)

    Sastry, S.; Debenedetti, P. G.; Stillinger, F. H.

    1999-01-01

    We study the properties of local potential energy minima (‘inherent structures’) sampled by liquids at low temperatures as an approach to elucidating the mechanisms of the observed dynamical slowing down observed as the glass transition temperature is approached. This onset of slow dynamics...... inherent structure basins from that due to inter-basin transitions becomes valid at temperatures T...

  2. Dissipation of solar energy in landscape - controlled by management of water and vegetation

    Czech Academy of Sciences Publication Activity Database

    Pokorný, Jan

    2001-01-01

    Roč. 24, - (2001), s. 641-645 ISSN 0960-1481 R&D Projects: GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z6005908 Keywords : Solar energy dissipation * vegetation * production -evapotranspiration Subject RIV: DA - Hydrology ; Limnology Impact factor: 0.224, year: 2001

  3. Subjects of the energy industry under yen appreciation; Endakaka ni okeru energy sangyo no kadai

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    This paper studied effects of yen appreciation on the Japanese economy and changes in energy demand when assuming the medium-term yen appreciation trend, and subjects in the energy industry. The paper also refers to the trend of the Asian material industry largely influencing the energy supply/demand, the risk hedge problem of the exchange, and international cooperation and business development of the energy industry. The energy industry is extremely high in public interest and is rice of the industry. Therefore, the development of the business has focused on the domestic market. However, such a recognition is forced to be changed by waves of the worldwide deregulation. Discussions on foreign/domestic price differences caused by high yen and a series of deregulation policy in the energy industry affected thereby may be concrete signs. The subject in the energy industry under the yen appreciation is that the energy industry will be close to common sense in general industrial circles and change to an industry which is strong and internationally competitive enough to brave the exchange variation. 101 refs., 104 figs., 31 tabs.

  4. Energy management under liberalism and interventionism; La maitrise de l`energie entre liberalisme et interventionnisme

    Energy Technology Data Exchange (ETDEWEB)

    Finon, D.; Menanteau, P. [Grenoble Univ., Institute for Energy Economics and Policy (France)

    1999-11-01

    The deregulation of the energy industries and the globalization of markets in the developed world and the integration of the economies of developing countries into the world economy present a major challenge to the energy sector, not the least of them is response to the long term environmental challenges. It is clear that if the developed nations take their commitments seriously to reduce their greenhouse gas emissions, they also have to deal with the problem of depleting domestic resources and the risks attendant on the fact that the largest conventional energy sources are situated in regions of the world that are politically unstable. Deregulation, and complete reliance on market forces alone, as advocated by supply-side economics, does not suffice under such circumstances; government intervention of some form, such as energy substitution and energy conservation measures, appear to be inevitable. This paper explores the differences between regulated and deregulated energy economies, the influence of globalization, the global threat of environmental damage, the security of supply situation and the options available to both the energy-consuming developed nations and the energy-rich developing nations to find a resolution to the common problem of saving the environment despite widely diverging economic and social imperatives.

  5. Under-use of body energy and over-use of external energy

    Energy Technology Data Exchange (ETDEWEB)

    Norgard, Jorgen Stig [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Civil Engineering

    2005-07-01

    The world's affluent countries, such as the EU, are facing two severe problems with long-term consequences. One problem is the epidemic-like increase in adverse health effects, which are related to the increasing wealth, primarily appearing as obesity and its associated diseases. This is caused by overeating and under-use of the body energy, due to increased use of mechanized and energy consuming assistance for transport and other daily tasks. This connects to the other problem, namely these countries' excessive use of fossil fuels and other environmentally harmful forms of nature's external energy. This paper illuminates the options for integrated solutions to the two problems by making more use of body energy as a means to reduce the use of nature's external energy. First is listed a human's body energy used for various tasks and occupations, showing that a person's use of external energy is an order of magnitude higher, which can be expressed by the scores of 'energy slaves' each citizen utilizes. An extra health driven physical effort by humans seems to have negligible direct impact on energy consumption. The paper will, however, indicate examples of significant indirect savings of external energy, achieved by healthy extra human efforts. Also, the paper will suggest ways to integrate energy saving policies with health policies for organizing and designing cities and houses to be 'healthy inconvenient', encouraging or pushing people to use their body in their daily doings. This is an enormous challenge to the conventional way of thinking among architects, engineers, planners, as well as individuals in general.

  6. Optimal Placement of Energy Storage and Wind Power under Uncertainty

    Directory of Open Access Journals (Sweden)

    Pilar Meneses de Quevedo

    2016-07-01

    Full Text Available Due to the rapid growth in the amount of wind energy connected to distribution grids, they are exposed to higher network constraints, which poses additional challenges to system operation. Based on regulation, the system operator has the right to curtail wind energy in order to avoid any violation of system constraints. Energy storage systems (ESS are considered to be a viable solution to solve this problem. The aim of this paper is to provide the best locations of both ESS and wind power by optimizing distribution system costs taking into account network constraints and the uncertainty associated to the nature of wind, load and price. To do that, we use a mixed integer linear programming (MILP approach consisting of loss reduction, voltage improvement and minimization of generation costs. An alternative current (AC linear optimal power flow (OPF, which employs binary variables to define the location of the generation, is implemented. The proposed stochastic MILP approach has been applied to the IEEE 69-bus distribution network and the results show the performance of the model under different values of installed capacities of ESS and wind power.

  7. Energy Efficiency and Conservation Attitudes: An Exploration of a Landscape of Choices

    Science.gov (United States)

    McClaren, Mersiha Spahic

    This study explored energy-related attitudes and energy-saving behaviors that are no- or low-cost and relatively simple to perform. This study relied on two data sources: a longitudinal but cross-sectional survey of 4,102 U.S. residents (five biennial waves of this survey were conducted from 2002 to 2010) and a 2010 cross-sectional survey of 2,000 California residents. These two surveys contained data on two no- and low-cost behaviors: changing thermostat setting to save energy (no-cost behavior) and CFL installation behavior (low-cost behavior). In terms of attitudes, two attitudinal measures emerged from these data following a Cronbach's alpha and Confirmatory Factor Analysis (CFA): the pro-environmental attitude and concern for the energy use in the U.S. society. These two attitudes, along with other socio-demographic and external factors (home ownership, weather, price of energy, etc.), were examined to assess whether attitude-behavior relationships persisted over time, were more prominent across certain groups, or were constrained by income or other socio-demographic factors. Three theoretical viewpoints of how attitudes may relate to behavior guided the analysis on how attitudes and contextual factors may inter-relate either directly or through a moderator variable to affect thermostat-setting and CFL installation behavior. Results from these analyses revealed four important patterns. First, a relationship between the pro-environmental attitude and the two behaviors (thermostat-setting and CFL installation behavior) was weak but persistent across time. Second, financial factors such as income moderated the pro-environmental attitude and CFL installation relationship, indicating that the pro-environmental attitude could influence the behavior in those situations where financial resources are sufficient to comfortably allow the consumer to participate. Third, this study documented that most people reported changing thermostat settings to save energy or having

  8. Planning nuclear energy centers under technological and demand uncertainty

    International Nuclear Information System (INIS)

    Meier, P.M.; Palmedo, P.F.

    1976-01-01

    The question considered is whether new nuclear power plants should be located in nuclear energy centers, or ''power parks'' with co-located fabrication and reprocessing facilities. That issue has been addressed in a recent study by the Nuclear Regulatory Commission and remains under investigation at Brookhaven and elsewhere. So far, however, the advisability of this policy has been analyzed primarily within the framework of a single view of the future. Suggestions of the types of questions that should be asked regarding this policy if it is properly to be viewed as an example of decision making under uncertainty are made. It is concluded that ''A consideration of the various uncertainties involved in the question of dispersed vs. remote siting of energy facilities introduces a number of new elements into the analysis. On balance those considerations provide somewhat greater support for the clustered concept. The NEC approach seems to provide somewhat greater flexibility in accomodating possible future electricity generating technologies. Increased regulatory and construction efficiencies possible in an NEC reduces the impact of demand uncertainty as does the lower costs associated with construction acceleration or deceleration.'' It is also noted that, in the final analysis, ''it is the public's perception of the relative costs and benefits of a measure that determine the acceptability or unacceptability of a particular innovation,'' not the engineer's cost/benefit analysis. It is further noted that if the analysis can identify limits on analytical methods and models, it will not make the job of energy decision-making any easier, but it may make the process more responsive to its impact on society

  9. Energy landscapes shape microbial communities in hydrothermal systems on the Arctic Mid-Ocean Ridge

    OpenAIRE

    Dahle, H?kon; ?kland, Ingeborg; Thorseth, Ingunn H; Pederesen, Rolf B; Steen, Ida H

    2015-01-01

    Methods developed in geochemical modelling combined with recent advances in molecular microbial ecology provide new opportunities to explore how microbial communities are shaped by their chemical surroundings. Here, we present a framework for analyses of how chemical energy availability shape chemotrophic microbial communities in hydrothermal systems through an investigation of two geochemically different basalt-hosted hydrothermal systems on the Arctic Mid-Ocean Ridge: the Soria Moria Vent f...

  10. Landscapes of lost energy: counterfactual geographical imaginary for a more sustainable society

    Czech Academy of Sciences Publication Activity Database

    Van der Horst, Dan

    2014-01-01

    Roč. 22, č. 2 (2014), s. 66-72 ISSN 1210-8812 R&D Projects: GA MŠk EE2.3.20.0025 Institutional support: RVO:68145535 Keywords : counterfactual * imagery * imagination * energy literacy Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.872, year: 2014 http://www.geonika.cz/EN/research/ENMgr/MGR_2014_02.pdf

  11. Landscapes of Lost Energy: Counterfactual Geographical Imaginary for A More Sustainable Society

    Directory of Open Access Journals (Sweden)

    van der Horst Dan

    2014-07-01

    Full Text Available The quest for sustainable energy, one of the greatest challenges of the 21st century, calls for more input from academics than 'simply' producing good science. Geographical imaginations are as old as storytelling and mapmaking, but this essay is neither about 'long ago and far away', nor about utopian energy futures. This is a call to geographers to engage with 'alternative present' energy scenarios, using the full range of analytical and discursive tools at our disposal. Drawing on a diverse tradition of imagined spaces and the awareness of absences (material, relational or otherwise, geographers should be able to contribute to the quest for a more sustainable society by assessing, envisaging, and communicating a counterfactual 'here and now', based on good practices existing right now, but not (yet right here. We need to understand how much more sustainable our bit of the planet would be if we could just, environmentally speaking, 'keep up' with the best of our neighbours. This counterfactual present should be seen as neither radical nor utopian, because it only assumes the historic adoption of best practices which we now know to be feasible and successful. And if thi alternative current scenario looks radically different from the 'real' state we are in, then this goes to show how radically unsustainable our business-as-usual approach has been.

  12. RAAAF's office landscape The End of Sitting: Energy expenditure and temporary comfort when working in non-sitting postures.

    Directory of Open Access Journals (Sweden)

    Simone R Caljouw

    Full Text Available An earlier study suggested that the activity-inviting office landscape called "The End of Sitting", designed by Rietveld Architecture Art Affordances (RAAAF, should be considered as an alternative working environment to prevent sedentary behavior. The End of Sitting lacks chairs and tables but consists instead of a myriad of sloped surfaces at different heights that afford workers to stand, lean or recline at different locations. In this study, we assessed the impact of four of its workspaces on physical intensity, temporary comfort and productivity of office work and compared the outcomes with sitting and standing behind a desk. Twenty-four participants worked for 10 minutes in each of the six test conditions. Energy expenditure, measured by indirect calorimetry, and heart rate were recorded. Questionnaires were used to assess the perceived comfort. The number of words found in the word search test was counted as a measure of productivity. The majority of The End of Sitting workspaces led to a significant increase in energy expenditure compared with sitting behind a desk (ps < .05. Average MET values ranged from 1.40 to 1.58 which is a modest rise in energy expenditure compared to sitting (1.32 METs and not significantly different from standing (1.47 METs. The scores on the general comfort scale indicated that some workspaces were less comfortable than sitting (ps < .05, but the vast majority of participants reported that at least one of The End of Sitting workspaces was equally or more comfortable than sitting. No differences in productivity between the test conditions were found. Further long-term studies are required to assess the behavioral adaptations, productivity and the level of comfort when using The End of Sitting as a permanent office.

  13. Spatial demographic models to inform conservation planning of golden eagles in renewable energy landscapes

    Science.gov (United States)

    Wiens, J. David; Schumaker, Nathan H.; Inman, Richard D.; Esque, Todd C.; Longshore, Kathleen M.; Nussear, Kenneth E

    2017-01-01

    Spatial demographic models can help guide monitoring and management activities targeting at-risk species, even in cases where baseline data are lacking. Here, we provide an example of how site-specific changes in land use and anthropogenic stressors can be incorporated into a spatial demographic model to investigate effects on population dynamics of Golden Eagles (Aquila chrysaetos). Our study focused on a population of Golden Eagles exposed to risks associated with rapid increases in renewable energy development in southern California, U.S.A. We developed a spatially explicit, individual-based simulation model that integrated empirical data on demography of Golden Eagles with spatial data on the arrangement of nesting habitats, prey resources, and planned renewable energy development sites. Our model permitted simulated eagles of different stage-classes to disperse, establish home ranges, acquire prey resources, prospect for breeding sites, and reproduce. The distribution of nesting habitats, prey resources, and threats within each individual's home range influenced movement, reproduction, and survival. We used our model to explore potential effects of alternative disturbance scenarios, and proposed conservation strategies, on the future distribution and abundance of Golden Eagles in the study region. Results from our simulations suggest that probable increases in mortality associated with renewable energy infrastructure (e.g., collisions with wind turbines and vehicles, electrocution on power poles) could have negative consequences for population trajectories, but that site-specific conservation actions could reduce the magnitude of negative effects. Our study demonstrates the use of a flexible and expandable modeling framework to incorporate spatially dependent processes when determining relative effects of proposed management options to Golden Eagles and their habitats.

  14. Energy-landscape analysis of the two-dimensional nearest-neighbor φ⁴ model.

    Science.gov (United States)

    Mehta, Dhagash; Hauenstein, Jonathan D; Kastner, Michael

    2012-06-01

    The stationary points of the potential energy function of the φ⁴ model on a two-dimensional square lattice with nearest-neighbor interactions are studied by means of two numerical methods: a numerical homotopy continuation method and a globally convergent Newton-Raphson method. We analyze the properties of the stationary points, in particular with respect to a number of quantities that have been conjectured to display signatures of the thermodynamic phase transition of the model. Although no such signatures are found for the nearest-neighbor φ⁴ model, our study illustrates the strengths and weaknesses of the numerical methods employed.

  15. Energy landscape of the reactions governing the Na+ deeply occluded state of the Na+/K+-ATPase in the giant axon of the Humboldt squid.

    Science.gov (United States)

    Castillo, Juan P; De Giorgis, Daniela; Basilio, Daniel; Gadsby, David C; Rosenthal, Joshua J C; Latorre, Ramon; Holmgren, Miguel; Bezanilla, Francisco

    2011-12-20

    The Na(+)/K(+) pump is a nearly ubiquitous membrane protein in animal cells that uses the free energy of ATP hydrolysis to alternatively export 3Na(+) from the cell and import 2K(+) per cycle. This exchange of ions produces a steady-state outwardly directed current, which is proportional in magnitude to the turnover rate. Under certain ionic conditions, a sudden voltage jump generates temporally distinct transient currents mediated by the Na(+)/K(+) pump that represent the kinetics of extracellular Na(+) binding/release and Na(+) occlusion/deocclusion transitions. For many years, these events have escaped a proper thermodynamic treatment due to the relatively small electrical signal. Here, taking the advantages offered by the large diameter of the axons from the squid Dosidicus gigas, we have been able to separate the kinetic components of the transient currents in an extended temperature range and thus characterize the energetic landscape of the pump cycle and those transitions associated with the extracellular release of the first Na(+) from the deeply occluded state. Occlusion/deocclusion transition involves large changes in enthalpy and entropy as the ion is exposed to the external milieu for release. Binding/unbinding is substantially less costly, yet larger than predicted for the energetic cost of an ion diffusing through a permeation pathway, which suggests that ion binding/unbinding must involve amino acid side-chain rearrangements at the site.

  16. An integrated approach to radionuclide flow in semi-natural ecosystems underlying exposure pathways to man. Final report of the LANDSCAPE project

    Energy Technology Data Exchange (ETDEWEB)

    Moberg, L.; Hubbard, L.; Avila, R.; Wallberg, L. [Swedish Radiation Protection Inst., Stockholm (Sweden); Feoli, E.; Scimone, M.; Milesi, C. [Trieste Univ. (Italy); Mayes, B.; Iason, G. [Macaulay Land Use Research Inst., Aberdeen (United Kingdom); Rantavaara, A.; Vetikko, V. [Radiation and Nuclear Safety Authority, Helsinki (Finland); Bergman, R.; Nylen, T. [National Defence Research Establishment, Umeaa (Sweden); Palo, T.; White, N. [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Faculty of Forestry; Raitio, H.; Aro, L.; Kaunisto, S. [The Finnish Forest Research Inst., Parkano (Finland); Guillitte, O. [Faculte Univ. des Sciences Agronomiques de Gembloux (Belgium)

    1999-10-01

    The general objective of the LANDSCAPE project has been to obtain a basis for reliable assessments of the radiation exposure to man under different time scales from radionuclides in plant and animal products of representative forest ecosystems in Europe. The work has been focussed on radiocaesium, {sup 134}Cs, {sup 137}Cs. In particular, the project has included (i) to quantify some major processes which influence the radiocaesium contamination of vegetation and fungi, (ii) to quantify radiocaesium intake of key herbivores, particularly free ranging moose, relative to food availability and degree of contamination, (iii) to quantify the influence of forest management on radiocaesium dynamics, and (iv) to incorporate these processes in dynamic models. The LANDSCAPE project has been the combined effort of eight research groups from five European countries, and this report describes the results obtained during 30 months of common work.

  17. An integrated approach to radionuclide flow in semi-natural ecosystems underlying exposure pathways to man. Final report of the LANDSCAPE project

    International Nuclear Information System (INIS)

    Moberg, L.; Hubbard, L.; Avila, R.; Wallberg, L.; Feoli, E.; Scimone, M.; Milesi, C.; Mayes, B.; Iason, G.; Rantavaara, A.; Vetikko, V.; Bergman, R.; Nylen, T.; Palo, T.; White, N.; Guillitte, O.

    1999-10-01

    The general objective of the LANDSCAPE project has been to obtain a basis for reliable assessments of the radiation exposure to man under different time scales from radionuclides in plant and animal products of representative forest ecosystems in Europe. The work has been focussed on radiocaesium, 134 Cs, 137 Cs. In particular, the project has included (i) to quantify some major processes which influence the radiocaesium contamination of vegetation and fungi, (ii) to quantify radiocaesium intake of key herbivores, particularly free ranging moose, relative to food availability and degree of contamination, (iii) to quantify the influence of forest management on radiocaesium dynamics, and (iv) to incorporate these processes in dynamic models. The LANDSCAPE project has been the combined effort of eight research groups from five European countries, and this report describes the results obtained during 30 months of common work

  18. The market of energy storage. Stakes and perspectives by 2020 - Analysis of the competitive landscape

    International Nuclear Information System (INIS)

    2013-01-01

    Within a context of lack of regulatory framework, of existence of technological deadlocks, and of absence of any defined business model, this publication reports a study of the emerging market of energy storage. It examines the role public authorities can play to promote investments in this sector, what are the opportunities for operators, and which are the perspectives on the middle term for the French market. In order to highlight recent and future evolutions of stationary and embarked storage, the authors propose an analysis of the main market growth drivers and brakes, a focus on the impact of regulatory, legal, economic, tax-related, technological, and social-cultural factors on sector stakeholders. They also propose an overview of the market status for the cases of stationary and embarked storage, and of the main challenges for these both segments. A panorama of existing actors is given with an analysis of their position, strengths and weaknesses, and of the main axis of development for 4 categories of actors (industries, battery manufacturers, energy operators, and start ups)

  19. Energy landscape and dynamics of brain activity during human bistable perception.

    Science.gov (United States)

    Watanabe, Takamitsu; Masuda, Naoki; Megumi, Fukuda; Kanai, Ryota; Rees, Geraint

    2014-08-28

    Individual differences in the structure of parietal and prefrontal cortex predict the stability of bistable visual perception. However, the mechanisms linking such individual differences in brain structures to behaviour remain elusive. Here we demonstrate a systematic relationship between the dynamics of brain activity, cortical structure and behaviour underpinning bistable perception. Using fMRI in humans, we find that the activity dynamics during bistable perception are well described as fluctuating between three spatially distributed energy minimums: visual-area-dominant, frontal-area-dominant and intermediate states. Transitions between these energy minimums predicted behaviour, with participants whose brain activity tend to reflect the visual-area-dominant state exhibiting more stable perception and those whose activity transits to frontal-area-dominant states reporting more frequent perceptual switches. Critically, these brain activity dynamics are correlated with individual differences in grey matter volume of the corresponding brain areas. Thus, individual differences in the large-scale dynamics of brain activity link focal brain structure with bistable perception.

  20. Impacts of the cultivation of energy crops for generation of biogas on the landscape structure and avifauna; Auswirkungen des Energiepflanzenanbaus zur Biogaserzeugung auf Landschaftsstruktur und Avifauna

    Energy Technology Data Exchange (ETDEWEB)

    Ruehmkorf, Hilke

    2011-07-01

    In its effort to implement new climate and energy policies, Germany has been heavily promoting the adoption of renewable energies. This has brought about a dramatic change in the use of arable land during the last years. The primary objective of this study was therefore to assess the effect of energy cropping on existing landscape structures in intensively cultivated regions in the course of the year. According to the available structural parameters an investigation was conducted to ascertain the fallout of energy plant cultivation on both migratory and overwintering birds. The period covered entailed the winter months. Both the advent of the energy crops as well as the associated biogas facilities that sprang up outside built-in areas seem to have reshaped the existing agricultural landscape. Hence, an additional aim of this study was to identify birds that use biogas plants for breeding or as a feeding habitat in winter. In conclusion, it can be asserted that energy crops can definitely contribute to the expansion of structural diversity in the agricultural landscape provided those energy crops were not cultivated on a large scale prior to the advent of the biogas facilities. Hence, there is still room for further energy crop diversification as its potential has not been exhausted. During the winter months mostly common species such as the carrion crow or the wood pigeon consider the maize fields as a viable source of nutrition. Cranes are seen as newcomers, as they probably started resting in the 'Boerde' precisely due to the advent of energy maize cultivation. And more availability of nourishment when the ground is covered by snow is another benefit the avifauna reaps from biogas plants. However, for endangered farmland birds this type of nutrition is a rarely used source, as it runs counter to their escape strategies and food preferences. For these species the habitat function and the food availability depends especially on how the land is managed (e

  1. Diffusion of a particle in the spatially correlated exponential random energy landscape: Transition from normal to anomalous diffusion

    Science.gov (United States)

    Novikov, S. V.

    2018-01-01

    Diffusive transport of a particle in a spatially correlated random energy landscape having exponential density of states has been considered. We exactly calculate the diffusivity in the nondispersive quasi-equilibrium transport regime for the 1D transport model and found that for slow decaying correlation functions the diffusivity becomes singular at some particular temperature higher than the temperature of the transition to the true non-equilibrium dispersive transport regime. It means that the diffusion becomes anomalous and does not follow the usual ∝ t1/2 law. In such situation, the fully developed non-equilibrium regime emerges in two stages: first, at some temperature there is the transition from the normal to anomalous diffusion, and then at lower temperature the average velocity for the infinite medium goes to zero, thus indicating the development of the true dispersive regime. Validity of the Einstein relation is discussed for the situation where the diffusivity does exist. We provide also some arguments in favor of conservation of the major features of the new transition scenario in higher dimensions.

  2. Low-coverage surface diffusion in complex periodic energy landscapes. II. Analytical solution for systems with asymmetric hops

    Science.gov (United States)

    Gosálvez, Miguel A.; Otrokov, Mikhail M.; Ferrando, Nestor; Ryabishchenkova, Anastasia G.; Ayuela, Andres; Echenique, Pedro M.; Chulkov, Evgueni V.

    2016-05-01

    This is part II in a series of two papers that introduce a general expression for the tracer diffusivity in complex, periodic energy landscapes with M distinct hop rates in one-, two-, and three-dimensional diluted systems (low coverage, single-tracer limit). While Part I [Gosálvez et al., Phys. Rev. B 93, 075429 (2016), 10.1103/PhysRevB.93.075429] focuses on the analysis of diffusion in systems where the end sites of the hops are located symmetrically with respect to the hop origins (symmetric hops), as encountered in many ideal surfaces and bulk materials, this report (Part II) presents a more general approach to determining the tracer diffusivity in systems where the end sites can be located asymmetrically with respect to the hop origins (asymmetric hops), as observed in reconstructed and/or chemically modified surfaces and/or bulk materials. The obtained diffusivity formulas for numerous systems are validated against kinetic Monte Carlo simulations and previously reported analytical expressions based on the continuous-time random walk (CTRW) method. The proposed method corrects some of the CTRW formulas and provides new expressions for difficult cases that have not been solved earlier. This demonstrates the ability of the proposed formalism to describe tracer diffusion.

  3. Information Resources in High-Energy Physics Surveying the Present Landscape and Charting the Future Course

    CERN Document Server

    Gentil-Beccot, Anne; Mele, Salvatore; Holtkamp, Annette; O'Connell, Heath B; Brooks, Travis C

    2009-01-01

    Access to previous results is of paramount importance in the scientific process. Recent progress in information management focuses on building e-infrastructures for the optimization of the research workflow, through both policy-driven and user-pulled dynamics. For decades, High-Energy Physics (HEP) has pioneered innovative solutions in the field of information management and dissemination. In light of a transforming information environment, it is important to assess the current usage of information resources by researchers and HEP provides a unique test-bed for this assessment. A survey of about 10% of practitioners in the field reveals usage trends and information needs. Community-based services, such as the pioneering arXiv and SPIRES systems, largely answer the need of the scientists, with a limited but increasing fraction of younger users relying on Google. Commercial services offered by publishers or database vendors are essentially unused in the field. The survey offers an insight into the most importan...

  4. Testing and evaluation of different energy storage devices for piezoelectric energy harvesting under road conditions

    Science.gov (United States)

    Gopalakrishnan, Pratheek

    The increasing needs in green technology have propelled the rapid development in energy conversion and the advancement of electric energy storage systems. A viable storage technology is needed to store intermittent electrical energy in different electronic applications. In this thesis, recent progress on the chemistry and design of batteries is summarized with their challenges and improvements. Along with that, electrolytic capacitors are also reviewed with their types, advantages and disadvantages of each in short. Super capacitors having higher surface area and thinner dielectrics than conventional capacitors along with hybrid capacitors, are discussed in detail. The potential of a hybrid capacitor, Ni(OH)2/ Active Carbon, compared with Ni-Cd batteries and electrolytic capacitors in the application of energy storage for high way energy harvesting has been explored in this work. Both the battery and the hybrid capacitor has been tested under various experimental conditions and their properties in relation to their chemical compositions are compared. The results obtained from the experiments have been analyzed and the most suitable energy storage devices have been selected with their application potential evaluated before drawing conclusion reported in this thesis.

  5. Photovoltaic performance and the energy landscape of CH3NH3PbI3.

    Science.gov (United States)

    Zhou, Yecheng; Huang, Fuzhi; Cheng, Yi-Bing; Gray-Weale, Angus

    2015-09-21

    Photovoltaic cells with absorbing layers of certain perovskites have power conversion efficiencies up to 20%. Among these materials, CH3NH3PbI3 is widely used. Here we use density-functional theory to calculate the energies and rotational energy barriers of a methylammonium ion in the α or β phase of CH3NH3PbI3 with differently oriented neighbouring methylammonium ions. Our results suggest the methylammonium ions in CH3NH3PbI3 prefer to rotate collectively, and to be parallel to their neighbours. Changes in polarization on rotation of methylammonium ions are two to three times larger than those on relaxation of the lead ion from the centre of its coordination shell. The preferences for parallel configuration and concerted rotation, with the polarisation changes, are consistent with ferroelectricity in the material, and indicate that this polarisation is governed by methylammonium orientational correlations. We show that the field due to this polarisation is strong enough to screen the field hindering charge transport, and find this screening field in agreement with experiment. We examine two possible mechanisms for the effect of methylammonium ion rotation on photovoltaic performance. One is that rearrangement of methylammoniums promotes the creation and transport of charge carriers. Some effective masses change greatly, but changes in band structure with methylammonium rotation are not large enough to explain current-voltage hysteresis behaviour. The second possible mechanism is that polarization screens the hindering electric field, which arises from charge accumulation in the transport layers. Polarization changes on methylammonium rotation favour this second mechanism, suggesting that collective reorientation of methylammonium ions in the bulk crystal are in significant part responsible for the hysteresis and power conversion characteristics of CH3NH3PbI3 photovoltaic cells.

  6. Nonequilibrium landscape theory of neural networks

    Science.gov (United States)

    Yan, Han; Zhao, Lei; Hu, Liang; Wang, Xidi; Wang, Erkang; Wang, Jin

    2013-01-01

    The brain map project aims to map out the neuron connections of the human brain. Even with all of the wirings mapped out, the global and physical understandings of the function and behavior are still challenging. Hopfield quantified the learning and memory process of symmetrically connected neural networks globally through equilibrium energy. The energy basins of attractions represent memories, and the memory retrieval dynamics is determined by the energy gradient. However, the realistic neural networks are asymmetrically connected, and oscillations cannot emerge from symmetric neural networks. Here, we developed a nonequilibrium landscape–flux theory for realistic asymmetrically connected neural networks. We uncovered the underlying potential landscape and the associated Lyapunov function for quantifying the global stability and function. We found the dynamics and oscillations in human brains responsible for cognitive processes and physiological rhythm regulations are determined not only by the landscape gradient but also by the flux. We found that the flux is closely related to the degrees of the asymmetric connections in neural networks and is the origin of the neural oscillations. The neural oscillation landscape shows a closed-ring attractor topology. The landscape gradient attracts the network down to the ring. The flux is responsible for coherent oscillations on the ring. We suggest the flux may provide the driving force for associations among memories. We applied our theory to rapid-eye movement sleep cycle. We identified the key regulation factors for function through global sensitivity analysis of landscape topography against wirings, which are in good agreements with experiments. PMID:24145451

  7. A landscape ecology approach to assessing development impacts in the tropics: A geothermal energy example in Hawaii

    Science.gov (United States)

    Griffith, J.A.; Trettin, C.C.; O'Neill, R. V.

    2002-01-01

    Geographic information systems (GIS) are increasingly being used in environmental impact assessments (EIA) because GIS is useful for analysing spatial impacts of various development scenarios. Spatially representing these impacts provides another tool for landscape ecology in environmental and geographical investigations by facilitating analysis of the effects of landscape patterns on ecological processes and examining change over time. Landscape ecological principles are applied in this study to a hypothetical geothermal development project on the Island of Hawaii. Some common landscape pattern metrics were used to analyse dispersed versus condensed development scenarios and their effect on landscape pattern. Indices of fragmentation and patch shape did not appreciably change with additional development. The amount of forest to open edge, however, greatly increased with the dispersed development scenario. In addition, landscape metrics showed that a human disturbance had a greater simplifying effect on patch shape and also increased fragmentation than a natural disturbance. The use of these landscape pattern metrics can advance the methodology of applying GIS to EIA.

  8. Simplifying the representation of complex free-energy landscapes using sketch-map

    Science.gov (United States)

    Ceriotti, Michele; Tribello, Gareth A.; Parrinello, Michele

    2011-01-01

    A new scheme, sketch-map, for obtaining a low-dimensional representation of the region of phase space explored during an enhanced dynamics simulation is proposed. We show evidence, from an examination of the distribution of pairwise distances between frames, that some features of the free-energy surface are inherently high-dimensional. This makes dimensionality reduction problematic because the data does not satisfy the assumptions made in conventional manifold learning algorithms We therefore propose that when dimensionality reduction is performed on trajectory data one should think of the resultant embedding as a quickly sketched set of directions rather than a road map. In other words, the embedding tells one about the connectivity between states but does not provide the vectors that correspond to the slow degrees of freedom. This realization informs the development of sketch-map, which endeavors to reproduce the proximity information from the high-dimensionality description in a space of lower dimensionality even when a faithful embedding is not possible. PMID:21730167

  9. Information resources in high-energy physics. Surveying the present landscape and charting the future course

    International Nuclear Information System (INIS)

    Gentil-Beccot, A.; Mele, S.; Holtkamp, A.; O'Connell, H.B.; Brooks, T.C.

    2008-04-01

    Access to previous results is of paramount importance in the scientific process. Recent progress in information management focuses on building e-infrastructures for the optimization of the research workflow, through both policy-driven and user-pulled dynamics. For decades, High-Energy Physics (HEP) has pioneered innovative solutions in the eld of infor- mation management and dissemination. In light of a transforming information environment, it is important to assess the current usage of information resources by researchers and HEP provides a unique test-bed for this assessment. A survey of about 10% of practitioners in the eld reveals usage trends and information needs. Community-based services, such as the pioneering arXiv and SPIRES systems, largely answer the need of the scientists, with a limited but increasing fraction of younger users relying on Google. Commercial services offered by publishers or database vendors are essentially unused in the eld. The survey o ers an in- sight into the most important features that users require to optimize their research workflow. These results inform the future evolution of information management in HEP and, as these researchers are traditionally ''early adopters'' of innovation in scholarly communication, can inspire developments of disciplinary repositories serving other communities. (orig.)

  10. Information Resources in High-Energy Physics: Surveying the Present Landscape and Charting the Future Course

    International Nuclear Information System (INIS)

    Gentil-Beccot, Anne; Mele, Salvatore; Holtkamp, Annette; O'Connell, Heath B.; Brooks, Travis C.

    2008-01-01

    Access to previous results is of paramount importance in the scientific process. Recent progress in information management focuses on building e-infrastructures for the optimization of the research workflow, through both policy-driven and user-pulled dynamics. For decades, High-Energy Physics (HEP) has pioneered innovative solutions in the field of information management and dissemination. In light of a transforming information environment, it is important to assess the current usage of information resources by researchers and HEP provides a unique test-bed for this assessment. A survey of about 10% of practitioners in the field reveals usage trends and information needs. Community-based services, such as the pioneering arXiv and SPIRES systems, largely answer the need of the scientists, with a limited but increasing fraction of younger users relying on Google. Commercial services offered by publishers or database vendors are essentially unused in the field. The survey offers an insight into the most important features that users require to optimize their research workflow. These results inform the future evolution of information management in HEP and, as these researchers are traditionally 'early adopters' of innovation in scholarly communication, can inspire developments of disciplinary repositories serving other communities

  11. Information Resources in High-Energy Physics: Surveying the Present Landscape and Charting the Future Course

    Energy Technology Data Exchange (ETDEWEB)

    Gentil-Beccot, Anne; Mele, Salvatore; Holtkamp, Annette; O' Connell, Heath B.; Brooks, Travis C.

    2008-04-22

    Access to previous results is of paramount importance in the scientific process. Recent progress in information management focuses on building e-infrastructures for the optimization of the research workflow, through both policy-driven and user-pulled dynamics. For decades, High-Energy Physics (HEP) has pioneered innovative solutions in the field of information management and dissemination. In light of a transforming information environment, it is important to assess the current usage of information resources by researchers and HEP provides a unique test-bed for this assessment. A survey of about 10% of practitioners in the field reveals usage trends and information needs. Community-based services, such as the pioneering arXiv and SPIRES systems, largely answer the need of the scientists, with a limited but increasing fraction of younger users relying on Google. Commercial services offered by publishers or database vendors are essentially unused in the field. The survey offers an insight into the most important features that users require to optimize their research workflow. These results inform the future evolution of information management in HEP and, as these researchers are traditionally 'early adopters' of innovation in scholarly communication, can inspire developments of disciplinary repositories serving other communities.

  12. Information resources in high-energy physics. Surveying the present landscape and charting the future course

    Energy Technology Data Exchange (ETDEWEB)

    Gentil-Beccot, A.; Mele, S. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Holtkamp, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); O' Connell, H.B. [Fermi National Accelerator Lab., Batavia, IL (United States); Brooks, T.C. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    2008-04-15

    Access to previous results is of paramount importance in the scientific process. Recent progress in information management focuses on building e-infrastructures for the optimization of the research workflow, through both policy-driven and user-pulled dynamics. For decades, High-Energy Physics (HEP) has pioneered innovative solutions in the eld of infor- mation management and dissemination. In light of a transforming information environment, it is important to assess the current usage of information resources by researchers and HEP provides a unique test-bed for this assessment. A survey of about 10% of practitioners in the eld reveals usage trends and information needs. Community-based services, such as the pioneering arXiv and SPIRES systems, largely answer the need of the scientists, with a limited but increasing fraction of younger users relying on Google. Commercial services offered by publishers or database vendors are essentially unused in the eld. The survey o ers an in- sight into the most important features that users require to optimize their research workflow. These results inform the future evolution of information management in HEP and, as these researchers are traditionally 'early adopters' of innovation in scholarly communication, can inspire developments of disciplinary repositories serving other communities. (orig.)

  13. Landscape Transformation under Global Environmental Change in Mediterranean Mountains: Agrarian Lands as a Guarantee for Maintaining Their Multifunctionality

    Directory of Open Access Journals (Sweden)

    Diego Varga

    2018-01-01

    Full Text Available The analysis of past and present patterns of agrarian mountain areas allows researchers to characterize the influence of landscape heterogeneity on biodiversity, cultural heritage, and forest fire hazard. This process was mapped, quantified, and described through the use of digital mapping (GIS and landscape indexes in a protected area in Alta Garrotxa (Catalonia, Spain. These areas require urgent management and modelling to provide alternative management scenarios, in order to maintain and recover habitats. A set of different scenarios have been designed using a multi-criteria evaluation and geospatial information available for the study area to identify the key areas for management action and to predict the potential effects on agricultural lands by prioritizing one or another management objective: biodiversity, landscape structure and perception, cultural heritage, fire hazard, and management cost. The observed progressive land abandonment of open areas with a small size and greater isolation will have a large impact on biodiversity and cultural heritage, and increase fire risk. Sustainable development will require planning objectives compatible with the conservation of biodiversity and the preservation of Mediterranean features with support for agricultural activities. This methodology can contribute to and be easily implemented by land managers, which could help to strengthen the link between managers and stakeholders.

  14. The importance of on-site evaluation for placing renewable energy in the landscape: A case study of the Búrfell wind farm (Iceland)

    Czech Academy of Sciences Publication Activity Database

    Frantál, Bohumil; Bevk, T.; van Veelen, B.; Hărmănescu, M.; Benediktsson, K.

    2017-01-01

    Roč. 25, č. 4 (2017), s. 234-247 ISSN 1210-8812 R&D Projects: GA ČR GA16-04483S Institutional support: RVO:68145535 Keywords : wind energy * landscape perception * Iceland Subject RIV: DE - Earth Magnetism, Geodesy, Geography OBOR OECD: Environmental sciences (social aspects) Impact factor: 2.149, year: 2016 http://www.geonika.cz/EN/research/ENMGRClanky/2017_4_FRANT%C3%81L.pdf

  15. Geoinformational modelling of the land use of Polesye and Opolje landscapes in Bryansk region (Russia) under conditions of 137Cs radionuclides contamination

    Science.gov (United States)

    Nenko, Christina; Linnik, Vitaliy; Volkova, Nadezhda

    2015-04-01

    Significant part of Russian Federation was contaminated by 137Cs radionuclides due to Chernobyl disaster in 1986. South-western part of Bryansk region has suffered the most. Study area (the central part of Bryansk region, Polesye and high plains landscapes) is situated outside the officially specified zone of contamination with contamination levels under 1 Ci / km2. Nevertheless, such contamination levels (which are 20 times greater than levels of global fallout) require particular attention as it may contain a threat of the land use and the health of population, living within the territory. Radioactive contamination within the model area was formed as a result of a "dry" deposition from the atmosphere. Consequently, the initial contamination of soil by isotopes 137Cs, unlike the western part of the Bryansk region, was spread relatively equally. The main part of 137Cs (up to 90%) in natural landscapes is contained in the top 5 cm of soil, which itself creates danger of biogeochemical migration from soil to plants. In agricultural landscapes under cultivation 137Cs is uniformly spread within a 20 cm layer of soil and can also come from soil to plants grown in the fields. The area of radioactive contamination that was formed during the period of deposition (late April - early May 1986), is exposed to the processes of secondary redistribution. It is influenced by several factors as topography, vegetation type, proportion of arable soils, soil humidity, soil texture etc. In the presented study there was evaluated the impact of these factors on the secondary redistribution of 137Cs. Sustainable development of agricultural production in the contaminated territories requires managing a number of measures to reduce radiation risks to the population. Regarding this point the greatest threat may be represented by milk production, as well as picking berries and mushrooms. Planning of the sustainable use of the territory requires an evaluation of contamination levels within

  16. BIODYNAMIC LANDSCAPE DESIGNING WITH BIOPONICS

    OpenAIRE

    SINGHANIA, PAWAN KUMAR; SINGHANIA, ARCHANA

    2014-01-01

    Never before the subject of Landscaping is covered in any of the past IFOAM Conferences. BIODYNAMIC Landscape Garden Designing is a new approach for Urban Landscaping where purposeful plantations are carried out, incorporating the science of BIOENERGETICS (measuring the energies in Plants, trees, and Earth Energies) which are also useful as Therapeutic (Healing) Gardens, suitable for Health Care institutes, Residential Complexes and Educational Institutions. The conventional approach is to fo...

  17. Optimal Time to Invest Energy Storage System under Uncertainty Conditions

    Directory of Open Access Journals (Sweden)

    Yongma Moon

    2014-04-01

    Full Text Available This paper proposes a model to determine the optimal investment time for energy storage systems (ESSs in a price arbitrage trade application under conditions of uncertainty over future profits. The adoption of ESSs can generate profits from price arbitrage trade, which are uncertain because the future marginal prices of electricity will change depending on supply and demand. In addition, since the investment is optional, an investor can delay adopting an ESS until it becomes profitable, and can decide the optimal time. Thus, when we evaluate this investment, we need to incorporate the investor’s option which is not captured by traditional evaluation methods. In order to incorporate these aspects, we applied real option theory to our proposed model, which provides an optimal investment threshold. Our results concerning the optimal time to invest show that if future profits that are expected to be obtained from arbitrage trade become more uncertain, an investor needs to wait longer to invest. Also, improvement in efficiency of ESSs can reduce the uncertainty of arbitrage profit and, consequently, the reduced uncertainty enables earlier ESS investment, even for the same power capacity. Besides, when a higher rate of profits is expected and ESS costs are higher, an investor needs to wait longer. Also, by comparing a widely used net present value model to our real option model, we show that the net present value method underestimates the value for ESS investment and misleads the investor to make an investment earlier.

  18. Nonlinear modeling of magnetorheological energy absorbers under impact conditions

    Science.gov (United States)

    Mao, Min; Hu, Wei; Choi, Young-Tai; Wereley, Norman M.; Browne, Alan L.; Ulicny, John; Johnson, Nancy

    2013-11-01

    Magnetorheological energy absorbers (MREAs) provide adaptive vibration and shock mitigation capabilities to accommodate varying payloads, vibration spectra, and shock pulses, as well as other environmental factors. A key performance metric is the dynamic range, which is defined as the ratio of the force at maximum field to the force in the absence of field. The off-state force is typically assumed to increase linearly with speed, but at the higher shaft speeds occurring in impact events, the off-state damping exhibits nonlinear velocity squared damping effects. To improve understanding of MREA behavior under high-speed impact conditions, this study focuses on nonlinear MREA models that can more accurately predict MREA dynamic behavior for nominal impact speeds of up to 6 m s-1. Three models were examined in this study. First, a nonlinear Bingham-plastic (BP) model incorporating Darcy friction and fluid inertia (Unsteady-BP) was formulated where the force is proportional to the velocity. Second, a Bingham-plastic model incorporating minor loss factors and fluid inertia (Unsteady-BPM) to better account for high-speed behavior was formulated. Third, a hydromechanical (HM) analysis was developed to account for fluid compressibility and inertia as well as minor loss factors. These models were validated using drop test data obtained using the drop tower facility at GM R&D Center for nominal drop speeds of up to 6 m s-1.

  19. Nonlinear modeling of magnetorheological energy absorbers under impact conditions

    International Nuclear Information System (INIS)

    Mao, Min; Hu, Wei; Choi, Young-Tai; Wereley, Norman M; Browne, Alan L; Ulicny, John; Johnson, Nancy

    2013-01-01

    Magnetorheological energy absorbers (MREAs) provide adaptive vibration and shock mitigation capabilities to accommodate varying payloads, vibration spectra, and shock pulses, as well as other environmental factors. A key performance metric is the dynamic range, which is defined as the ratio of the force at maximum field to the force in the absence of field. The off-state force is typically assumed to increase linearly with speed, but at the higher shaft speeds occurring in impact events, the off-state damping exhibits nonlinear velocity squared damping effects. To improve understanding of MREA behavior under high-speed impact conditions, this study focuses on nonlinear MREA models that can more accurately predict MREA dynamic behavior for nominal impact speeds of up to 6 m s −1 . Three models were examined in this study. First, a nonlinear Bingham-plastic (BP) model incorporating Darcy friction and fluid inertia (Unsteady-BP) was formulated where the force is proportional to the velocity. Second, a Bingham-plastic model incorporating minor loss factors and fluid inertia (Unsteady-BPM) to better account for high-speed behavior was formulated. Third, a hydromechanical (HM) analysis was developed to account for fluid compressibility and inertia as well as minor loss factors. These models were validated using drop test data obtained using the drop tower facility at GM R and D Center for nominal drop speeds of up to 6 m s −1 . (paper)

  20. Characterization of climate- and human-induced slope, soil and grassland dynamics in Bavarian landscapes under climate change

    Science.gov (United States)

    Waltl, Peter; Schwindt, Daniel; Völkel, Jörg

    2016-04-01

    Since the Neolithic Revolution the intensification of agriculture has been causing increased erosion in Bavarian landscapes. The correlated sediments often induce the formation of new colluvial and alluvial soils (WRB: Regic Anthrosol and Fluvisol i.a.). The soils themselves are able to absorb, bind, and store considerable amounts of C- and N-compounds. Therefore, they are important reactors regarding climate-relevant greenhouse-gas balances in the atmosphere. Learning about the exact spatial extent and thickness of these soils in representative landscapes, but also about their geneses and processes is essential. It allows for a detailed quantification and understanding of the current and potential properties and characteristics of these soils in their role of greenhouse-gas reactors. Two research locations were elected as representative Bavarian landscapes composed of different lithology and pedo-chemical environments (limestone versus crystalline setting): Rottenbuch is situated at the Ammer River in the Upper Bavarian pre-alpine forelands (Lkr. Weilheim-Schongau). The Otterbach Creek lies at the southwestern foothills of the Bavarian Forest at the Donaurandbruch tectonic line next to Donaustauf (Lkr. Regensburg). Detailed information on the soil horizons and layers within these research areas are accumulated by sounding or burrowing soil profiles and subsequently analyzing the soil samples in the lab. Geophysical methods, such as electrical resistivity tomography (ERT), seismic refraction tomography (SRT), and ground penetrating radar (GPR), allow for the extension of this point-source information into three dimensions. By repeatedly and regularly applying these methods, also temporal changes such as soil hydrology or freeze and thaw cycles can be monitored and their influence on fluxes and exchanges can be taken into account.

  1. State-and-transition simulation modeling to compare outcomes of alternative management scenarios under two natural disturbance regimes in a forested landscape in northeastern Wisconsin, USA

    Directory of Open Access Journals (Sweden)

    Amanda Swearingen

    2015-07-01

    Full Text Available Comparisons of the potential outcomes of multiple land management strategies and an understanding of the influence of potential increases in climate-related disturbances on these outcomes are essential for long term land management and conservation planning. To provide these insights, we developed an approach that uses collaborative scenario development and state-and-transition simulation modeling to provide land managers and conservation practitioners with a comparison of potential landscapes resulting from alternative management scenarios and climate conditions, and we have applied this approach in the Wild Rivers Legacy Forest (WRLF area in northeastern Wisconsin. Three management scenarios were developed with input from local land managers, scientists, and conservation practitioners: 1 continuation of current management, 2 expanded working forest conservation easements, and 3 cooperative ecological forestry. Scenarios were modeled under current climate with contemporary probabilities of natural disturbance and under increased probability of windthrow and wildfire that may result from climate change in this region. All scenarios were modeled for 100 years using the VDDT/TELSA modeling suite. Results showed that landscape composition and configuration were relatively similar among scenarios, and that management had a stronger effect than increased probability of windthrow and wildfire. These findings suggest that the scale of the landscape analysis used here and the lack of differences in predominant management strategies between ownerships in this region play significant roles in scenario outcomes. The approach used here does not rely on complex mechanistic modeling of uncertain dynamics and can therefore be used as starting point for planning and further analysis.

  2. Landscape Ecology

    DEFF Research Database (Denmark)

    Christensen, Andreas Aagaard; Brandt, Jesper; Svenningsen, Stig Roar

    2017-01-01

    pattern analysis and ecological interaction of land units. The landscape is seen as a holon: an assemblage of interrelated phenomena, both cultural and biophysical, that together form a complex whole. Enduring challenges to landscape ecology include the need to develop a systematic approach able......Landscape ecology is an interdisciplinary field of research and practice that deals with the mutual association between the spatial configuration and ecological functioning of landscapes, exploring and describing processes involved in the differentiation of spaces within landscapes......, and the ecological significance of the patterns which are generated by such processes. In landscape ecology, perspectives drawn from existing academic disciplines are integrated based on a common, spatially explicit mode of analysis developed from classical holistic geography, emphasizing spatial and landscape...

  3. Landscape Ecology

    DEFF Research Database (Denmark)

    Christensen, Andreas Aagaard; Brandt, Jesper; Svenningsen, Stig Roar

    2017-01-01

    Landscape ecology is an interdisciplinary field of research and practice that deals with the mutual association between the spatial configuration and ecological functioning of landscapes, exploring and describing processes involved in the differentiation of spaces within landscapes......, and the ecological significance of the patterns which are generated by such processes. In landscape ecology, perspectives drawn from existing academic disciplines are integrated based on a common, spatially explicit mode of analysis developed from classical holistic geography, emphasizing spatial and landscape...... pattern analysis and ecological interaction of land units. The landscape is seen as a holon: an assemblage of interrelated phenomena, both cultural and biophysical, that together form a complex whole. Enduring challenges to landscape ecology include the need to develop a systematic approach able...

  4. Energy policy under the aspect of international economic interdependencies

    International Nuclear Information System (INIS)

    Michaelis, H.

    1978-01-01

    A few introductory remarks on the status of and on prospects fo the world energy economy as well as on reasons given for the necessity of a world-wide coordination of energy policy and economic policy are followed by an explanation of the policy led by oil extracting countries and of the endeavour of western industrialized countries to reduce oil imports. Even if the state of utilizing nuclear energy does not yet present a sufficient alternative, the international nuclear energy continues to be directed towards this goal. Seen from an international viewpoint, relieving contributions are to be expected from energy-conservation-actions and from the development of regenerative energy sources. (UA) [de

  5. Prospects for nuclear energy under a Reagan administration

    International Nuclear Information System (INIS)

    Doub, W.O.

    1981-01-01

    The press is told that media treatment of nuclear energy has been superficial and often irresponsible. The press is responsible for much of the public's apprehension, and should work in cooperation with the industry to present objective facts of nuclear energy economics and safety. The Reagan administration intends to reverse the impact of the Carter policies on the nuclear option by supporting commercial reprocessing and shifting the focus from conservation and renewable energy sources back to nuclear energy. New management structure and responsibilities will address the US decline as a world leader in nuclear energy and realign the country with its traditional trading partners. This will reverse the erosion of the Non-Proliferation Treaty and the authority of the International Energy Agency. Current economic problems could delay utility plant expansion without some steps toward deregulation

  6. Rupturing the hemi-fission intermediate in membrane fission under tension: Reaction coordinates, kinetic pathways, and free-energy barriers

    Science.gov (United States)

    Zhang, Guojie; Müller, Marcus

    2017-08-01

    Membrane fission is a fundamental process in cells, involved inter alia in endocytosis, intracellular trafficking, and virus infection. Its underlying molecular mechanism, however, is only incompletely understood. Recently, experiments and computer simulation studies have revealed that dynamin-mediated membrane fission is a two-step process that proceeds via a metastable hemi-fission intermediate (or wormlike micelle) formed by dynamin's constriction. Importantly, this hemi-fission intermediate is remarkably metastable, i.e., its subsequent rupture that completes the fission process does not occur spontaneously but requires additional, external effects, e.g., dynamin's (unknown) conformational changes or membrane tension. Using simulations of a coarse-grained, implicit-solvent model of lipid membranes, we investigate the molecular mechanism of rupturing the hemi-fission intermediate, such as its pathway, the concomitant transition states, and barriers, as well as the role of membrane tension. The membrane tension is controlled by the chemical potential of the lipids, and the free-energy landscape as a function of two reaction coordinates is obtained by grand canonical Wang-Landau sampling. Our results show that, in the course of rupturing, the hemi-fission intermediate undergoes a "thinning → local pinching → rupture/fission" pathway, with a bottle-neck-shaped cylindrical micelle as a transition state. Although an increase of membrane tension facilitates the fission process by reducing the corresponding free-energy barrier, for biologically relevant tensions, the free-energy barriers still significantly exceed the thermal energy scale kBT.

  7. Operations Optimization of Hybrid Energy Systems under Variable Markets

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jun; Garcia, Humberto E.

    2016-07-01

    Hybrid energy systems (HES) have been proposed to be an important element to enable increasing penetration of clean energy. This paper investigates the operations flexibility of HES, and develops a methodology for operations optimization to maximize its economic value based on predicted renewable generation and market information. The proposed operations optimizer allows systematic control of energy conversion for maximal economic value, and is illustrated by numerical results.

  8. Complex free-energy landscapes in biaxial nematic liquid crystals and the role of repulsive interactions: A Wang-Landau study

    Science.gov (United States)

    Kamala Latha, B.; Murthy, K. P. N.; Sastry, V. S. S.

    2017-09-01

    General quadratic Hamiltonian models, describing the interaction between liquid-crystal molecules (typically with D2 h symmetry), take into account couplings between their uniaxial and biaxial tensors. While the attractive contributions arising from interactions between similar tensors of the participating molecules provide for eventual condensation of the respective orders at suitably low temperatures, the role of cross coupling between unlike tensors is not fully appreciated. Our recent study with an advanced Monte Carlo technique (entropic sampling) showed clearly the increasing relevance of this cross term in determining the phase diagram (contravening in some regions of model parameter space), the predictions of mean-field theory, and standard Monte Carlo simulation results. In this context, we investigated the phase diagrams and the nature of the phases therein on two trajectories in the parameter space: one is a line in the interior region of biaxial stability believed to be representative of the real systems, and the second is the extensively investigated parabolic path resulting from the London dispersion approximation. In both cases, we find the destabilizing effect of increased cross-coupling interactions, which invariably result in the formation of local biaxial organizations inhomogeneously distributed. This manifests as a small, but unmistakable, contribution of biaxial order in the uniaxial phase. The free-energy profiles computed in the present study as a function of the two dominant order parameters indicate complex landscapes. On the one hand, these profiles account for the unusual thermal behavior of the biaxial order parameter under significant destabilizing influence from the cross terms. On the other, they also allude to the possibility that in real systems, these complexities might indeed be inhibiting the formation of a low-temperature biaxial order itself—perhaps reflecting the difficulties in their ready realization in the laboratory.

  9. The global mean energy balance under cloud-free conditions

    Science.gov (United States)

    Wild, Martin; Hakuba, Maria; Folini, Dois; Ott, Patricia; Long, Charles

    2017-04-01

    A long standing problem of climate models is their overestimation of surface solar radiation not only under all-sky, but also under clear-sky conditions (Wild et al. 1995, Wild et al. 2006). This overestimation reduced over time in consecutive model generations due to the simulation of stronger atmospheric absorption. Here we analyze the clear sky fluxes of the latest climate model generation from the Coupled Model Intercomparison Project Phase 5 (CMIP5) against an expanded and updated set of direct observations from the Baseline Surface Radiation Network (BSRN). Clear sky climatologies from these sites have been composed based on the Long and Ackermann (2000) clear sky detection algorithm (Hakuba et al. 2017), and sampling issues when comparing with model simulated clear sky fluxes have been analyzed in Ott (2017). Overall, the overestimation of clear sky insolation in the CMIP5 models is now merely 1-2 Wm-2 in the multimodel mean, compared to 4 Wm-2 in CMIP3 and 6 Wm-2 in AMIPII (Wild et al. 2006). Still a considerable spread in the individual model biases is apparent, ranging from -2 Wm-2 to 10 Wm-2 when averaged over 53 globally distributed BSRN sites. This bias structure is used to infer best estimates for present day global mean clear sky insolation, following an approach developped in Wild et al. (2013, 2015, Clim. Dyn.) for all sky fluxes. Thereby the flux biases in the various models are linearly related to their respective global means. A best estimate can then be inferred from the linear regression at the intersect where the bias against the surface observations becomes zero. This way we obtain a best estimate of 247 Wm-2 for the global mean insolation at the Earth surface under cloud free conditions, and a global mean absorbed solar radiation of 214 Wm-2 in the cloud-free atmosphere, assuming a global mean surface albedo of 13.5%. Combined with a best estimate for the net influx of solar radiation at the Top of Atmosphere under cloud free conditions

  10. Energy infrastructure in India: Profile and risks under climate change

    DEFF Research Database (Denmark)

    Garg, Amit; Naswa, Prakriti; Shukla, P.R.

    2015-01-01

    India has committed large investments to energy infrastructure assets-power plants, refineries, energy ports, pipelines, roads, railways, etc. The coastal infrastructure being developed to meet the rising energy imports is vulnerable to climate extremes. This paper provides an overview of climate...... risks to energy infrastructures in India and details two case studies - a crude oil importing port and a western coast railway transporting coal. The climate vulnerability of the port has been mapped using an index while that of the railway has been done through a damage function for RCP 4.5.0 and 8...

  11. Energy infrastructure in India: Profile and risks under climate change

    International Nuclear Information System (INIS)

    Garg, Amit; Naswa, Prakriti; Shukla, P.R.

    2015-01-01

    India has committed large investments to energy infrastructure assets-power plants, refineries, energy ports, pipelines, roads, railways, etc. The coastal infrastructure being developed to meet the rising energy imports is vulnerable to climate extremes. This paper provides an overview of climate risks to energy infrastructures in India and details two case studies – a crude oil importing port and a western coast railway transporting coal. The climate vulnerability of the port has been mapped using an index while that of the railway has been done through a damage function for RCP 4.5.0 and 8.5 scenarios. Our analysis shows that risk management through adaptation is likely to be very expensive. The system risks can be even greater and might adversely affect energy security and access objectives. Aligning sustainable development and climate adaptation measures can deliver substantial co-benefits. The key policy recommendations include: i) mandatory vulnerability assessment to future climate risks for energy infrastructures; ii) project and systemic risks in the vulnerability index; iii) adaptation funds for unmitigated climate risks; iv) continuous monitoring of climatic parameters and implementation of adaptation measures, and iv) sustainability actions along energy infrastructures that enhance climate resilience and simultaneously deliver co-benefits to local agents. -- Highlights: •Climate risks to energy infrastructures adversely impact energy security. •Case studies of a port and a railway show their future climate change vulnerability. •Managing climate-induced risks through preventive adaptation policies

  12. Land-Sparing Opportunities for Solar Energy Development in Agricultural Landscapes: A Case Study of the Great Central Valley, CA, United States.

    Science.gov (United States)

    Hoffacker, Madison K; Allen, Michael F; Hernandez, Rebecca R

    2017-12-19

    Land-cover change from energy development, including solar energy, presents trade-offs for land used for the production of food and the conservation of ecosystems. Solar energy plays a critical role in contributing to the alternative energy mix to mitigate climate change and meet policy milestones; however, the extent that solar energy development on nonconventional surfaces can mitigate land scarcity is understudied. Here, we evaluate the land sparing potential of solar energy development across four nonconventional land-cover types: the built environment, salt-affected land, contaminated land, and water reservoirs (as floatovoltaics), within the Great Central Valley (CV, CA), a globally significant agricultural region where land for food production, urban development, and conservation collide. Furthermore, we calculate the technical potential (TWh year -1 ) of these land sparing sites and test the degree to which projected electricity needs for the state of California can be met therein. In total, the CV encompasses 15% of CA, 8415 km 2 of which was identified as potentially land-sparing for solar energy development. These areas comprise a capacity-based energy potential of at least 17 348 TWh year -1 for photovoltaic (PV) and 2213 TWh year -1 for concentrating solar power (CSP). Accounting for technology efficiencies, this exceeds California's 2025 projected electricity demands up to 13 and 2 times for PV and CSP, respectively. Our study underscores the potential of strategic renewable energy siting to mitigate environmental trade-offs typically coupled with energy sprawl in agricultural landscapes.

  13. [Developmental instability of the organism as a result of pessimization of environment under anthropogenic transformation of natural landscapes].

    Science.gov (United States)

    Shadrina, E G; Vol'pert, Ia L

    2014-01-01

    The value of fluctuating asymmetry is considered to be an indicator of the developmental instability of the organism. The consequences of activities of the mining industry plants, which are characterized by alienation and transformation of large areas of natural landscapes, are analyzed as an anthropogenic factor. The objects of study were small mammals (northern red-backed (Clethrionomys rutilus) and gray red-backed (Clethrionomys rufocanus) voles, tundra vole (Microtus oeconomus), Laxmann's (Sorex caecutiens) and tundra (S. tundrensis) shrews) and trees (Japanese white birch (Betula platyphylla), Betula divaricate, Betula exilis, Duschekiafruticosa, and common osier (Salix viminalis)). In total, 3500 skulls and approximately 30000 leaves collected in the taiga zone of Yakutia were studied. The index offluctuating asymmetry, as well as population parameters and composition of small mammal communities, were analyzed. The data on the value of the fluctuating asymmetry in the studied species in natural habitats are given. It is shown that, in natural conditions, this parameter can rise with deterioration in living conditions, particularly at the ecological periphery of the range. Anthropogenic transformation of natural landscapes creates an "anthropogenic periphery" and causes changes similar to the adaptive responses at the northern limit of the distribution of species. It was found that, through pollution and disruption of ecosystems, the mining industry affects all levels of organization of the living matter, but the population and cenotic parameters give an unambiguous response only at macroanthropogenic transformations. Increase in the level of fluctuating asymmetry is the most sensitive indicator of anthropogenic impact and it should also be taken into account that disruptions in the developmental stability of an organism reflect the destructive processes occurring in the population and community.

  14. Analysis on Japan's long-term energy outlook considering massive deployment of variable renewable energy under nuclear energy scenario

    International Nuclear Information System (INIS)

    Komiyama, Ryoichi; Fujii, Yasumasa

    2012-01-01

    This paper investigates Japan's long-term energy outlook to 2050 considering massive deployment of solar photovoltaic (PV) system and wind power generation under nuclear energy scenario. The extensive introduction of PV system and wind power system are expected to play an important role in enhancing electricity supply security after Fukushima Nuclear Power Accident which has increased the uncertainty of future additional construction of nuclear power plant in Japan. On these backgrounds, we develop integrated energy assessment model comprised of both econometric energy demand and supply model and optimal power generation mix model. The latter model is able to explicitly analyze the impact of output fluctuation in variable renewable in detailed time resolution at 10 minutes on consecutive 365 days, incorporating the role of stationary battery technology. Simulation results reveal that intermittent fluctuation derived from high penetration level of those renewables is controlled by quick load following operation by natural gas combined cycle power plant, pumped-storage hydro power, stationary battery technology and the output suppression of PV and wind power. The results show as well that massive penetration of the renewables does not necessarily require the comparable scale of stationary battery capacity. Additionally, on the scenario which assumes the decommissioning of nuclear power plants which lifetime are over 40 years, required PV capacity in 2050 amounts to more than double of PV installment potential in both building and abandoned farmland area. (author)

  15. Renewable energy sources project appraisal under uncertainty: the case of wind energy exploitation within a changing energy market environment

    International Nuclear Information System (INIS)

    Venetsanos, K.; Angelopoulou, P.; Tsoutsos, T.

    2002-01-01

    There are four elements, which contribute to the oncoming increase of electricity demand: climate changes, the expected growth rates of EU Member State economies, changes in the consumption patterns and the introduction of new technologies. The new deregulated Electricity Market is expected to respond to this challenge and the energy supply will be adequate and cost effective within this new environment which offers promising opportunities for power producers both existing and newcomers. In this paper a framework for the appraisal of power projects under uncertainty within a competitive market environment is identified, focusing on the electricity from Renewable Energy Sources. To this end the wind energy-to-electricity, production in Greece will serve as a case study. The subject matter is centred on the following areas: the uncertainties within the new deregulated energy market; the evaluation methods including an analysis of the introduced uncertainties after deregulation and a new approach to project evaluation using the real options, as well as comparison of the valuation methodologies within the new environment drawing from the case for Greece. (author)

  16. Algorithmic power management - Energy minimisation under real-time constraints

    NARCIS (Netherlands)

    Gerards, Marco Egbertus Theodorus

    2014-01-01

    Energy consumption is a major concern for designers of embedded devices. Especially for battery operated systems (like many embedded systems), the energy consumption limits the time for which a device can be active, and the amount of processing that can take place. In this thesis we study how the

  17. Algorithmic power management: energy minimisation under real-time constraints

    NARCIS (Netherlands)

    Gerards, Marco Egbertus Theodorus

    2014-01-01

    Energy consumption is a major concern for designers of embedded devices. Especially for battery operated systems (like many embedded systems), the energy consumption limits the time for which a device can be active, and the amount of processing that can take place. In this thesis we study how the

  18. Future bio-energy potential under various natural constraints

    International Nuclear Information System (INIS)

    Vuuren, Detlef P. van; Vliet, Jasper van; Stehfest, Elke

    2009-01-01

    Potentials for bio-energy have been estimated earlier on the basis of estimates of potentially available land, excluding certain types of land use or land cover (land required for food production and forests). In this paper, we explore how such estimates may be influenced by other factors such as land degradation, water scarcity and biodiversity concerns. Our analysis indicates that of the original bio-energy potential estimate of 150, 80 EJ occurs in areas classified as from mild to severe land degradation, water stress, or with high biodiversity value. Yield estimates were also found to have a significant impact on potential estimates. A further 12.5% increase in global yields would lead to an increase in bio-energy potential of about 50%. Changes in bio-energy potential are shown to have a direct impact on bio-energy use in the energy model TIMER, although the relevant factor is the bio-energy potential at different cost levels and not the overall potential.

  19. Free energy in plasmas under wave-induced diffusion

    International Nuclear Information System (INIS)

    Fisch, N.J.

    1993-05-01

    When waves propagate through a bounded plasma, the wave may be amplified or damped at the expense of the plasma kinetic energy. In many cases of interest, the primary effect of the wave is to cause plasma diffusion in velocity and configuration space. In the absence of collisions, the rearrangement of the plasma conserves entropy, as large-grain structures are mixed and fine-grain structures emerge. The maximum extractable energy by waves so diffusing the plasma is a quantity of fundamental interest; it can be defined, but it is difficult to calculate. Through the consideration of specific examples, certain strategies for maximizing energy extraction are identified

  20. RAAAF's office landscape The End of Sitting : Energy expenditure and temporary comfort when working in non-sitting postures

    NARCIS (Netherlands)

    Caljouw, Simone R.; de Vries, Rutger; Withagen, Rob

    2017-01-01

    An earlier study suggested that the activity-inviting office landscape called "The End of Sitting", designed by Rietveld Architecture Art Affordances (RAAAF), should be considered as an alternative working environment to prevent sedentary behavior. The End of Sitting lacks chairs and tables but

  1. Shared Solar: Current Landscape, Market Potential, and the Impact of Federal Securities Regulation; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-05-27

    This presentation provides a high-level overview of the current U.S. shared solar landscape, the impact that a given shared solar program's structure has on requiring federal securities oversight, as well as an estimate of market potential for U.S. shared solar deployment.

  2. Harvesting Energy from Vibrations of the Underlying Structure

    DEFF Research Database (Denmark)

    Han, Bo; Vssilaras, S; Papadias, C.B.

    2013-01-01

    The use of wireless sensors for structural health monitoring offers several advantages such as small size, easy installation and minimal intervention on existing structures. However the most significant concern about such wireless sensors is the lifetime of the system, which depends heavily...... to the long-term structural health of a building or bridge, but at the same time they can be exploited as a power source to power the wireless sensors that are monitoring this structural health. This paper presents a new energy harvesting method based on a vibration driven electromagnetic harvester. By using...... on the type of power supply. No matter how energy efficient the operation of a battery operated sensor is, the energy of the battery will be exhausted at some point. In order to achieve a virtually unlimited lifetime, the sensor node should be able to recharge its battery in an easy way. Energy harvesting...

  3. Empowered? Evaluating Japan's national energy strategy under the DPJ administration

    International Nuclear Information System (INIS)

    Valentine, Scott; Sovacool, Benjamin K.; Matsuura, Masahiro

    2011-01-01

    In August 2009, after 54 years of virtually unbroken rule, Japan's Liberal Democratic Party (LDP) was ousted from power by the Democratic Party of Japan (DPJ). The DPJ's campaign platform included a pledge to facilitate extreme reductions in greenhouse gas (GHG) emissions. Yet, at the COP16 meeting in Cancun, Japan announced that it would not accept further emission reduction targets without broader commitment from all nations. This paper seeks to explain this dichotomy by employing a targeted stakeholder evaluation based on surveys with 321 Japanese citizens to assess the extent to which influential stakeholder groups in Japan supports a potentially costly transition to a low-carbon energy infrastructure amidst severe economic challenges that the nation faces. Findings help explain Japan's adversarial role in COP16 negotiations in Cancun, despite the stated GHG reduction ambitions of Japan's current ruling party. The analysis concludes that if the DPJ does embrace aggressive CO 2 reduction targets in the future, the strategic focus will likely mirror the former ruling party's energy policy of bolstering nuclear power generation capacity and promoting energy efficiency improvements while exhibiting lukewarm commitment to supporting capacity development in alternative sources of energy supply such as solar panels and wind turbines. - Research highlights: → Public consensus exists regarding which energy policy goals are important in Japan. → Minor perceptual differences are not of a catalytic nature. → Public consensus does not deviate significantly from past LDP energy policy. → Unlikely that the DPJ will pursue costly energy transition initiatives. → Likely that the DPJ energy strategy will be substantively similar to LDP strategy. → Any differences in strategy will focus on CO 2 reduction magnitude not substance.

  4. Evaluating investments in renewable energy under policy risks

    International Nuclear Information System (INIS)

    Gatzert, Nadine; Vogl, Nikolai

    2016-01-01

    The considerable amount of required infrastructure and renewable energy investments expected in the forthcoming years also implies an increasingly relevant contribution of private and institutional investors. In this context, especially regulatory and policy risks have been shown to play a major role for investors when evaluating investments in renewable energy and should thus also be taken into account in risk assessment and when deriving risk-return profiles. In this paper, we provide a stochastic model framework to quantify policy risks associated with renewable energy investments (e.g. a retrospective reduction of a feed-in tariff), thereby also taking into account energy price risk, resource risk, and inflation risk. The model is illustrated by means of simulations and scenario analyses, and it makes use of expert estimates and fuzzy set theory for quantifying policy risks. Our numerical results for a portfolio of onshore wind farms in Germany and France show that policy risk can strongly impact risk-return profiles, and that cross-country diversification effects can considerably decrease the overall risk for investors. - Highlights: •Quantification of policy risks associated with renewable energy investments. •Results emphasize that policy risk has a major impact on risk and return. •Study of the cross-country diversification potential. •Cross-country diversification can considerably decrease the risk for an investor.

  5. A stochastic multi-agent optimization model for energy infrastructure planning under uncertainty and competition.

    Science.gov (United States)

    2017-07-04

    This paper presents a stochastic multi-agent optimization model that supports energy infrastruc- : ture planning under uncertainty. The interdependence between dierent decision entities in the : system is captured in an energy supply chain network, w...

  6. Equilibrium transitions from non-renewable energy to renewable energy under capacity constraints

    OpenAIRE

    Amigues, Jean-Pierre; Ayong Le Kama, Alain; Moreaux, Michel

    2015-01-01

    We study the transition between non renewable and renewable energy sources with adjustment costs over the production capacity of renewable energy. Assuming constant variable marginal costs for both energy sources, convex adjustment costs and a more expensive renewable energy, we show the following. With sufficiently abundant non renewable energy endowments, the dynamic equilibrium path is composed of a first time phase of only non renewable energy use followed by a transition phase substituti...

  7. Energy behavior of solar hot water systems under different conditions

    International Nuclear Information System (INIS)

    Fuentes Lombá, Osmanys; Torres Ten, Alonso; Arzuaga Machado, Yusnel; Hernández, Massipe J. Raúl; Cueva Gonzales, Wagner

    2017-01-01

    By means of numerical simulations in TRNSYS v14 the influence of the solar absorption area of a system for heating water with solar energy, composed by a flat solar collector and a tank thermo-accumulator, on its energy efficiency. For the study, the solar collectors EDWARDS, ISOFOTÓN 1, ISOFOTÓN 2, MADE, ROLDAN and IBERSOLAR of absorption area 2, 1,9, 1,88, 2, 1,9 and 2,3 m2 respectively were chosen. For each collector, the energy performance was simulated for one year, setting 200 L for the accumulation volume and 50 °C for the intake temperature. Despite the different characteristics of each collector, their behavior is quite similar showing a very mature technology. (author)

  8. Optimisation of fuel stocks under liberalisation of energy market

    International Nuclear Information System (INIS)

    Shipkovs, P.; Sitenko, L.; Kashkarova, G.

    2001-01-01

    The paper discusses the influence of regional fuel stocks on the reliability of the energy sector's activities in a given region. The authors give classification of stocks by their purpose and describe their role in avoiding energy shortage situations. The fuel deficiency at a regional fuel market is shown in connection with the resulting loss for the national economy. The authors employ imitative modelling for investigation of fuel supply schemes acting in Latvia. They estimate possible expenses on the maintenance of fuels - such as gas, residual oil, and coal - for different variants of fuel delivery. (author)

  9. Underlying Beliefs Associated With College Student Consumption of Energy Beverages.

    Science.gov (United States)

    Thorlton, Janet; Collins, William B

    2018-01-01

    College students are heavy consumers of energy beverages, yet further study is needed to better understand determinants of use. The purpose of this cross-sectional study ( N = 283) was to identify beliefs explaining unsafe consumption practices. A principal components analysis revealed three eigenvalues >1 explaining approximately 55% of the variance (health and appearance, performance and fatigue, and recreation and alcohol). Multiple regression analysis explained 75% of the variance for intent to consume. Standardized beta for attitude and subjective norms was p behavioral control was p Students viewed energy beverages as useful for managing health and appearance and performance and fatigue, and as a way to enhance recreation and alcohol consumption.

  10. Landscape Ecology

    DEFF Research Database (Denmark)

    Christensen, Andreas Aagaard; Brandt, Jesper; Svenningsen, Stig Roar

    2017-01-01

    pattern analysis and ecological interaction of land units. The landscape is seen as a holon: an assemblage of interrelated phenomena, both cultural and biophysical, that together form a complex whole. Enduring challenges to landscape ecology include the need to develop a systematic approach able...

  11. Nordic Landscape

    DEFF Research Database (Denmark)

    Hjortshøj, Rasmus

    2017-01-01

    This Box Set NORDIC LANDSCAPE presents Nordic Territories, a project by Rasmus Hjortshøj, exploring the man-made landscapes of the coastal territories and the entanglement of society and nature in times where it is no longer merely mankind subjected to nature, but where nature is equally being...

  12. Elastic layer under axisymmetric indentation and surface energy effects

    Science.gov (United States)

    Intarit, Pong-in; Senjuntichai, Teerapong; Rungamornrat, Jaroon

    2018-04-01

    In this paper, a continuum-based approach is adopted to investigate the contact problem of an elastic layer with finite thickness and rigid base subjected to axisymmetric indentation with the consideration of surface energy effects. A complete Gurtin-Murdoch surface elasticity is employed to consider the influence of surface stresses. The indentation problem of a rigid frictionless punch with arbitrary axisymmetric profiles is formulated by employing the displacement Green's functions, derived with the aid of Hankel integral transform technique. The problem is solved by assuming the contact pressure distribution in terms of a linear combination of admissible functions and undetermined coefficients. Those coefficients are then obtained by employing a collocation technique and an efficient numerical quadrature scheme. The accuracy of proposed solution technique is verified by comparing with existing solutions for rigid indentation on an elastic half-space. Selected numerical results for the indenters with flat-ended cylindrical and paraboloidal punch profiles are presented to portray the influence of surface energy effects on elastic fields of the finite layer. It is found that the presence of surface stresses renders the layer stiffer, and the size-dependent behavior of elastic fields is observed in the present solutions. In addition, the surface energy effects become more pronounced with smaller contact area; thus, the influence of surface energy cannot be ignored in the analysis of indentation problem especially when the indenter size is very small such as in the case of nanoindentation.

  13. The Energy Under Our Feet: A Study of Solar Radiation

    Science.gov (United States)

    Weiss, I.

    2016-12-01

    In this experiment I tested if asphalt pavement can produce enough solar heat to produce energy through a system that uses water, solar energy and heat. A setup that can conserve the water and prevent it from evaporating, as well as measuring the energy production is required to run this experiment. I have done a lot of research on this experiment and found that there are several variables that impact the results of this experiment. 1. The surface temperature compared to the air temperature 2. The Geographical location of the pavement 3. The time of the year 4. Cloud coverage for the day Overall there will be many variables I will have to keep out of the experiment such as temperature ranges, season changes and geographical location. My constant will be my location at 33.7086o North and 117.9564o West. Asphalt pavements do not reflect the sunlight and hence heat up faster than a light surface that would reflect the sunlight. This means the Asphalt absorbs the solar radiation, which increases the temperature of the air around the asphalt contributing to what is known as the urban heat island effect. This heating in turn contributes to the formation of smog and ozone products. With the population still growing this would also mean an increase in this temperature and hence an increase in smog and ozone, creating a significant health concern. Cities need to start looking at ways to cool their pavement and find ways to harvest the energy created by their streets. Installing pipes with water can provide that solution and not only reduce the heat reflected from the pavement but also harvest energy from this setup, and decrease the smog production and maintain a balance in ozone levels. As well as the asphalt needed to run the testing, a Stirling engine is required. A Stirling Engine is a highly efficient engine that can run on a variety of heat sources. Because it is highly compatible with alternative energy and renewable energy sources it could become increasingly

  14. Planetary Landscape Geography

    Science.gov (United States)

    Hargitai, H.

    INTRODUCTION Landscape is one of the most often used category in physical ge- ography. The term "landshap" was introduced by Dutch painters in the 15-16th cen- tury. [1] The elements that build up a landscape (or environment) on Earth consists of natural (biogenic and abiogenic - lithologic, atmospheric, hydrologic) and artificial (antropogenic) factors. Landscape is a complex system of these different elements. The same lithology makes different landscapes under different climatic conditions. If the same conditions are present, the same landscape type will appear. Landscapes build up a hierarchic system and cover the whole surface. On Earth, landscapes can be classified and qualified according to their characteristics: relief forms (morphology), and its potential economic value. Aesthetic and subjective parameters can also be considered. Using the data from landers and data from orbiters we can now classify planetary landscapes (these can be used as geologic mapping units as well). By looking at a unknown landscape, we can determine the processes that created it and its development history. This was the case in the Pathfinder/Sojourner panoramas. [2]. DISCUSSION Planetary landscape evolution. We can draw a raw landscape develop- ment history by adding the different landscape building elements to each other. This has a strong connection with the planet's thermal evolution (age of the planet or the present surface materials) and with orbital parameters (distance from the central star, orbit excentricity etc). This way we can build a complex system in which we use differ- ent evolutional stages of lithologic, atmospheric, hydrologic and biogenic conditions which determine the given - Solar System or exoplanetary - landscape. Landscape elements. "Simple" landscapes can be found on asteroids: no linear horizon is present (not differentiated body, only impact structures), no atmosphere (therefore no atmospheric scattering - black sky as part of the landscape) and no

  15. Industrious Landscaping

    DEFF Research Database (Denmark)

    Brichet, Nathalia Sofie; Hastrup, Frida

    2018-01-01

    This article offers a history of landscaping at Søby brown coal beds – a former mining site in western Denmark. Exploring this industrial landscape through a series of projects that have made different natural resources appear, we argue that what is even recognized as resources shifts over time...... has been seen interchangeably to rest with brown coal business, inexpensive estates for do-it-yourself people, pasture for grazing, and recreational forest, among other things. We discuss these rifts in landscaping, motivated by what we refer to as industriousness, to show that in an industrial site...... analysis of shifting landscape projects and has an essential methodological corollary, namely that fieldwork must be improvisational, situated, and humble. Rather than finding the ‘right’ field materials for a canonical landscape history of Søby, we develop a method of ‘dustballing’ – being blown here...

  16. Unnameable landscapes

    Directory of Open Access Journals (Sweden)

    John Stuart-Murray

    1995-10-01

    Full Text Available This paper outlines the key concepts of opacity, back formation and toponymic activity used by place name historians, and relates them to the naming of contemporary artefacts in the cultural landscape. It categorises place names according to a three-layered analytical model of landscape and argues that place naming is now carried out largely within a cultural framework. Exceptions are names given by modern recreationalists who have regained something of the intimate relationship with the land possessed by earlier agricultural societies. This view is supported by findings that students of landscape architecture have difficulty in naming and describing character where landscapes have been shaped largely by physical and biological processes. It is also consistent with the increasing articulation of landscapes at the cultural level independent of physical and natural process, allowed by the sophistication of modern technology.

  17. Interactions between Energy Efficiency Programs funded under the Recovery Act and Utility Customer-Funded Energy Efficiency Programs

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, Charles A.; Stuart, Elizabeth; Hoffman, Ian; Fuller, Merrian C.; Billingsley, Megan A.

    2011-02-25

    Since the spring of 2009, billions of federal dollars have been allocated to state and local governments as grants for energy efficiency and renewable energy projects and programs. The scale of this American Reinvestment and Recovery Act (ARRA) funding, focused on 'shovel-ready' projects to create and retain jobs, is unprecedented. Thousands of newly funded players - cities, counties, states, and tribes - and thousands of programs and projects are entering the existing landscape of energy efficiency programs for the first time or expanding their reach. The nation's experience base with energy efficiency is growing enormously, fed by federal dollars and driven by broader objectives than saving energy alone. State and local officials made countless choices in developing portfolios of ARRA-funded energy efficiency programs and deciding how their programs would relate to existing efficiency programs funded by utility customers. Those choices are worth examining as bellwethers of a future world where there may be multiple program administrators and funding sources in many states. What are the opportunities and challenges of this new environment? What short- and long-term impacts will this large, infusion of funds have on utility customer-funded programs; for example, on infrastructure for delivering energy efficiency services or on customer willingness to invest in energy efficiency? To what extent has the attribution of energy savings been a critical issue, especially where administrators of utility customer-funded energy efficiency programs have performance or shareholder incentives? Do the new ARRA-funded energy efficiency programs provide insights on roles or activities that are particularly well-suited to state and local program administrators vs. administrators or implementers of utility customer-funded programs? The answers could have important implications for the future of U.S. energy efficiency. This report focuses on a selected set of ARRA

  18. EROI of crystalline silicon photovoltaics : Variations under different assumptions regarding manufacturing energy inputs and energy output

    OpenAIRE

    Lundin, Johan

    2013-01-01

    Installed photovoltaic nameplate power have been growing rapidly around the worldin the last few years. But how much energy is returned to society (i.e. net energy) by this technology, and which factors contribute the most to the amount of energy returned? The objective of this thesis was to examine the importance of certain inputs and outputs along the solar panel production chain and their effect on the energy return on (energy) investment (EROI) for crystalline wafer-based photovoltaics. A...

  19. Energy Saving Potential by Utilizing Natural Ventilation under Warm Conditions

    DEFF Research Database (Denmark)

    Oropeza-Perez, Ivan; Østergaard, Poul Alberg

    2014-01-01

    –airflow simulations of 27 common cases of dwellings (considered as one thermal zone) based on the combination of specific features of the building design, occupancy and climate conditions. The energy saving potential is assessed then by the use of a new assessment method suitable for large-scale scenarios using......The objective of this article is to show the potential of natural ventilation as a passive cooling method within the residential sector of countries which are located in warm conditions using Mexico as a case study. The method is proposed as performing, with a simplified ventilation model, thermal...... the actual number of air-conditioned dwellings distributed among the 27 cases. Thereby, the energy saving is presented as the difference in the cooling demand of the dwelling during one year without and with natural ventilation, respectively. Results indicate that for hot-dry conditions, buildings with high...

  20. The significance of the amorphous potential energy landscape for dictating glassy dynamics and driving solid-state crystallisation

    DEFF Research Database (Denmark)

    Ruggiero, Michael T; Krynski, Marcin; Kissi, Eric Ofosu

    2017-01-01

    The fundamental origins surrounding the dynamics of disordered solids near their characteristic glass transitions continue to be fiercely debated, even though a vast number of materials can form amorphous solids, including small-molecule organic, inorganic, covalent, metallic, and even large...... biological systems. The glass-transition temperature, Tg, can be readily detected by a diverse set of techniques, but given that these measurement modalities probe vastly different processes, there has been significant debate regarding the question of why Tg can be detected across all of them. Here we show...... clear experimental and computational evidence in support of a theory that proposes that the shape and structure of the potential-energy surface (PES) is the fundamental factor underlying the glass-transition processes, regardless of the frequency that experimental methods probe. Whilst this has been...

  1. Silicon passivation study under low energy electron irradiation conditions

    International Nuclear Information System (INIS)

    Cluzel, R.

    2010-01-01

    Backside illuminated thinned CMOS (Complementary Metal Oxide Semiconductor) imaging system is a technology developed to increase the signal to noise ratio and the sensibility of such sensors. This configuration is adapted to the electrons detection from the energy range of [1 - 12 keV]. The impinging electron creates by multiplication several hundreds of secondary electrons close to the surface. A P ++ highly-doped passivation layer of the rear face is required to reduce the secondary electron surface recombination rate. Thanks to the potential barrier induced by the P ++ layer, the passivation layer increases the collected charges number and so the sensor collection gain. The goal of this study is to develop some experimental methods in order to determine the effect of six different passivation processes on the collection gain. Beforehand, the energy profile deposited by an incident electron is studied with the combination of Monte-Carlo simulations and some analytical calculations. The final collection gain model shows that the mirror effect from the passivation layer is a key factor at high energies whereas the passivation layer has to be as thin as possible at low energies. A first experimental setup which consists in irradiating P ++ /N large diodes allows to study the passivation process impacts on the surface recombinations. Thanks to a second setup based on a single event upset directly on thinned CMOS sensor, passivation techniques are discriminated in term of mirror effect and the implied spreading charges. The doping atoms activation laser annealing is turn out to be a multiplication gain inhomogeneity source impacting directly the matrix uniformity. (author)

  2. Energy imbalance underlying the development of childhood obesity

    DEFF Research Database (Denmark)

    Butte, Nancy F; Christiansen, Edmund; Sørensen, Thorkild I A

    2007-01-01

    OBJECTIVE: To develop a model based on empirical data and human energetics to predict the total energy cost of weight gain and obligatory increase in energy intake and/or decrease in physical activity level associated with weight gain in children and adolescents. RESEARCH METHODS AND PROCEDURES......%), and DIEE (10%). Observed median (10th to 90th percentile) weight gain of 6.1 kg/yr (2.4 to 11.4 kg/yr) corresponds at physical activity level (PAL) = 1.5, 1.75, and 2.0 to a total energy cost of weight gain of 244 (93 to 448 kcal/d), 267 (101 to 485 kcal/d), and 290 kcal/d (110 to 527 kcal/d), respectively......: One-year changes in weight and body composition and basal metabolic rate (BMR) were measured in 488 Hispanic children and adolescents. Fat-free mass (FFM) and fat mass (FM) were measured by DXA and BMR by calorimetry. Model specifications include the following: body mass (BM) = FFM + FM, each...

  3. Metal azides under pressure: An emerging class of high energy ...

    Indian Academy of Sciences (India)

    with experiment. Our theoretical study proved that the materials under study may have the ability to form polymeric nitrogen because of the decrease in interazide ion distance and possible overlapping of N atomic orbitals. Keywords. Energetic materials; density functional theory; band gap; compressibility. 1. Introduction.

  4. The Potential and Flux Landscape Theory of Ecology

    Science.gov (United States)

    Zhang, Kun; Wang, Erkang; Wang, Jin

    2014-01-01

    The species in ecosystems are mutually interacting and self sustainable stable for a certain period. Stability and dynamics are crucial for understanding the structure and the function of ecosystems. We developed a potential and flux landscape theory of ecosystems to address these issues. We show that the driving force of the ecological dynamics can be decomposed to the gradient of the potential landscape and the curl probability flux measuring the degree of the breaking down of the detailed balance (due to in or out flow of the energy to the ecosystems). We found that the underlying intrinsic potential landscape is a global Lyapunov function monotonically going down in time and the topology of the landscape provides a quantitative measure for the global stability of the ecosystems. We also quantified the intrinsic energy, the entropy, the free energy and constructed the non-equilibrium thermodynamics for the ecosystems. We studied several typical and important ecological systems: the predation, competition, mutualism and a realistic lynx-snowshoe hare model. Single attractor, multiple attractors and limit cycle attractors emerge from these studies. We studied the stability and robustness of the ecosystems against the perturbations in parameters and the environmental fluctuations. We also found that the kinetic paths between the multiple attractors do not follow the gradient paths of the underlying landscape and are irreversible because of the non-zero flux. This theory provides a novel way for exploring the global stability, function and the robustness of ecosystems. PMID:24497975

  5. Industrious Landscaping

    DEFF Research Database (Denmark)

    Brichet, Nathalia Sofie; Hastrup, Frida

    2018-01-01

    This article offers a history of landscaping at Søby brown coal beds – a former mining site in western Denmark. Exploring this industrial landscape through a series of projects that have made different natural resources appear, we argue that what is even recognized as resources shifts over time...... has been seen interchangeably to rest with brown coal business, inexpensive estates for do-it-yourself people, pasture for grazing, and recreational forest, among other things. We discuss these rifts in landscaping, motivated by what we refer to as industriousness, to show that in an industrial site...

  6. Light energy allocation at PSII under field light conditions: how much energy is lost in NPQ-associated dissipation?

    Science.gov (United States)

    Endo, Tsuyoshi; Uebayashi, Nozomu; Ishida, Satoshi; Ikeuchi, Masahiro; Sato, Fumihiko

    2014-08-01

    In the field, plants are exposed to fluctuating light, where photosynthesis occurs under conditions far from a steady state. Excess energy dissipation associated with energy quenching of chlorophyll fluorescence (qE) functions as an efficient photo-protection mechanism in photosystem II. PsbS is an important regulator of qE, especially for the induction phase of qE. Beside the regulatory energy dissipation, some part of energy is lost through relaxation of excited chlorophyll molecules. To date, several models to quantify energy loss through these dissipative pathways in PSII have been proposed. In this short review, we compare and evaluate these models for PSII energy allocation when they are applied to non-steady state photosynthesis. As a case study, an investigation on energy allocation to qE-associated dissipation at PSII under non-steady state photosynthesis using PsbS-deficient rice transformants is introduced. Diurnal and seasonal changes in PSII energy allocation in rice under natural light are also presented. Future perspective of studies on PSII energy allocation is discussed. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  7. Advancing solar energy forecasting through the underlying physics

    Science.gov (United States)

    Yang, H.; Ghonima, M. S.; Zhong, X.; Ozge, B.; Kurtz, B.; Wu, E.; Mejia, F. A.; Zamora, M.; Wang, G.; Clemesha, R.; Norris, J. R.; Heus, T.; Kleissl, J. P.

    2017-12-01

    As solar power comprises an increasingly large portion of the energy generation mix, the ability to accurately forecast solar photovoltaic generation becomes increasingly important. Due to the variability of solar power caused by cloud cover, knowledge of both the magnitude and timing of expected solar power production ahead of time facilitates the integration of solar power onto the electric grid by reducing electricity generation from traditional ancillary generators such as gas and oil power plants, as well as decreasing the ramping of all generators, reducing start and shutdown costs, and minimizing solar power curtailment, thereby providing annual economic value. The time scales involved in both the energy markets and solar variability range from intra-hour to several days ahead. This wide range of time horizons led to the development of a multitude of techniques, with each offering unique advantages in specific applications. For example, sky imagery provides site-specific forecasts on the minute-scale. Statistical techniques including machine learning algorithms are commonly used in the intra-day forecast horizon for regional applications, while numerical weather prediction models can provide mesoscale forecasts on both the intra-day and days-ahead time scale. This talk will provide an overview of the challenges unique to each technique and highlight the advances in their ongoing development which come alongside advances in the fundamental physics underneath.

  8. Surface dose measurements under stretched, perforated thermoplast sheets and under protective wound dressings for high energy photon radiation

    International Nuclear Information System (INIS)

    Staudenraus, J.; Christ, G.

    2000-01-01

    Patient fixation masks made of perforated thermoplast sheets are widely used in radiotherapy. These masks in particular serve to immobilize the head and neck region during radiation treatment. We placed samples made of differently stretched, perforated mask material on the surface of a white polystyrene (RW3) phantom and measured for high energy photon beams from Co-60 radiation up to 25 MV bremsstrahlung the dose increase resulting from the build-up under the hole and bridge areas. Depending on the energy of the incident beam and the thickness of the stretched mask material we observed a dose increase under the bridges at the phantom surface of 55% up to 140% compared to the dose without a layer of mask material. Under a hole the dose increase is almost half the value found under a bridge. However, deeper than 1 mm under the phantom surface this difference in dose increase under holes and bridges decreases to less than 10%. The mean dose increase under a perforated thermoplast sheet is lower than the dose increase under a homogeneous sheet made of the same material with the same mean thickness. Radiation induced skin lesions or an ulcerating tumour, respectively, may require a protective wound dressing under a patient fixation mask during radiation therapy. Choosing a thin hydrocolloid wound dressing the additional dose increase of the skin, compared to the dose increase due to the fixation mask, can be kept low. (orig.) [de

  9. Energy utilization under different dietary regime in sheep

    International Nuclear Information System (INIS)

    Nasr, M.A.H.

    1982-01-01

    The present system of ruminant nutrition in egypt depends upon the agroindustrial by - products, crop residues and limited quantities of green fodders. Any future development will come through introducing non-traditional materials in ruminant rations and through benefiting from the recent scientific developments occurred in our understanding to the ruminal and post-ruminal digestion. Four rations, were tested throughout the present investigation, these diets consisted of molasses as low-cost, readily fermentable source of energy and as a good carrier for urea, and rice straw . On this diet the supply of amino acids may not be sufficient for moderate production levels by the animals.Hence, amino acids shortage and imbalance, in such animals has had to be expected

  10. Energy profile of nanobody–GFP complex under force

    International Nuclear Information System (INIS)

    Klamecka, Kamila; Severin, Philip M; Milles, Lukas F; Gaub, Hermann E; Leonhardt, Heinrich

    2015-01-01

    Nanobodies (Nbs)—the smallest known fully functional and naturally occuring antigen-binding fragments—have attracted a lot of attention throughout the last two decades. Exploring their potential beyond the current use requires more detailed characterization of their binding forces as those cannot be directly derived from the binding affinities. Here we used atomic force microscope to measure rupture force of the Nb–green fluorescent protein (GFP) complex in various pulling geometries and derived the energy profile characterizing the interaction along the direction of the pulling force. We found that—despite identical epitopes—the Nb binds stronger (41–56 pN) to enhanced GFP than to wild-type GFP (28–45 pN). Measured forces make the Nb–GFP pair a potent reference for investigating molecular forces in living systems both in and ex vivo. (paper)

  11. Energy profile of nanobody-GFP complex under force

    Science.gov (United States)

    Klamecka, Kamila; Severin, Philip M.; Milles, Lukas F.; Gaub, Hermann E.; Leonhardt, Heinrich

    2015-10-01

    Nanobodies (Nbs)—the smallest known fully functional and naturally occuring antigen-binding fragments—have attracted a lot of attention throughout the last two decades. Exploring their potential beyond the current use requires more detailed characterization of their binding forces as those cannot be directly derived from the binding affinities. Here we used atomic force microscope to measure rupture force of the Nb-green fluorescent protein (GFP) complex in various pulling geometries and derived the energy profile characterizing the interaction along the direction of the pulling force. We found that—despite identical epitopes—the Nb binds stronger (41-56 pN) to enhanced GFP than to wild-type GFP (28-45 pN). Measured forces make the Nb-GFP pair a potent reference for investigating molecular forces in living systems both in and ex vivo.

  12. Relativistic Killingbeck energy states under external magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Eshghi, M. [Islamic Azad University, Researchers and Elite Club, Central Tehran Branch, Tehran (Iran, Islamic Republic of); Mehraban, H. [Semnan University, Faculty of Physics, Semnan (Iran, Islamic Republic of); Ikhdair, S.M. [An-Najah National University, Department of Physics, Faculty of Science, Nablus, West Bank, Palestine (Country Unknown); Near East University, Department of Electrical Engineering, Nicosia, Northern Cyprus (Turkey)

    2016-07-15

    We address the behavior of the Dirac equation with the Killingbeck radial potential including the external magnetic and Aharonov-Bohm (AB) flux fields. The spin and pseudo-spin symmetries are considered. The correct bound state spectra and their corresponding wave functions are obtained. We seek such a solution using the biconfluent Heun's differential equation method. Further, we give some of our results at the end of this study. Our final results can be reduced to their non-relativistic forms by simply using some appropriate transformations. The spectra, in the spin and pseudo-spin symmetries, are very similar with a slight difference in energy spacing between different states. (orig.)

  13. Relativistic Killingbeck energy states under external magnetic fields

    International Nuclear Information System (INIS)

    Eshghi, M.; Mehraban, H.; Ikhdair, S.M.

    2016-01-01

    We address the behavior of the Dirac equation with the Killingbeck radial potential including the external magnetic and Aharonov-Bohm (AB) flux fields. The spin and pseudo-spin symmetries are considered. The correct bound state spectra and their corresponding wave functions are obtained. We seek such a solution using the biconfluent Heun's differential equation method. Further, we give some of our results at the end of this study. Our final results can be reduced to their non-relativistic forms by simply using some appropriate transformations. The spectra, in the spin and pseudo-spin symmetries, are very similar with a slight difference in energy spacing between different states. (orig.)

  14. 29 CFR 24.114 - District court jurisdiction of retaliation complaints under the Energy Reorganization Act.

    Science.gov (United States)

    2010-07-01

    ... the Energy Reorganization Act. 24.114 Section 24.114 Labor Office of the Secretary of Labor PROCEDURES... Provisions § 24.114 District court jurisdiction of retaliation complaints under the Energy Reorganization Act... the Energy Reorganization Act, and there is no showing that there has been delay due to the bad faith...

  15. Sustainable design of complex industrial and energy systems under uncertainty

    Science.gov (United States)

    Liu, Zheng

    Depletion of natural resources, environmental pressure, economic globalization, etc., demand seriously industrial organizations to ensure that their manufacturing be sustainable. On the other hand, the efforts of pursing sustainability also give raise to potential opportunities for improvements and collaborations among various types of industries. Owing to inherent complexity and uncertainty, however, sustainability problems of industrial and energy systems are always very difficult to deal with, which has made industrial practice mostly experience based. For existing research efforts on the study of industrial sustainability, although systems approaches have been applied in dealing with the challenge of system complexity, most of them are still lack in the ability of handling inherent uncertainty. To overcome this limit, there is a research need to develop a new generation of systems approaches by integrating techniques and methods for handling various types of uncertainties. To achieve this objective, this research introduced series of holistic methodologies for sustainable design and decision-making of industrial and energy systems. The introduced methodologies are developed in a systems point of view with the functional components involved in, namely, modeling, assessment, analysis, and decision-making. For different methodologies, the interval-parameter-based, fuzzy-logic-based, and Monte Carlo based methods are selected and applied respectively for handling various types of uncertainties involved, and the optimality of solutions is guaranteed by thorough search or system optimization. The proposed methods are generally applicable for any types of industrial systems, and their efficacy had been successfully demonstrated by the given case studies. Beyond that, a computational tool was designed, which provides functions on the industrial sustainability assessment and decision-making through several convenient and interactive steps of computer operation. This

  16. Synchronization of grid-connected renewable energy sources under highly distorted voltages and unbalanced grid faults

    DEFF Research Database (Denmark)

    Hadjidemetriou, Lenos; Kyriakides, Elias; Blaabjerg, Frede

    2013-01-01

    and dynamic synchronization of the interconnected renewable energy system under unbalanced grid faults and under highly harmonic distorted voltage. The outstanding performance of the suggested PLL is achieved by implementing an innovative multi-sequence/harmonic decoupling cell in order to dynamically cancel...... renewable energy systems. Therefore, the performance of the new PLL can increase the quality of the injected power under abnormal conditions and in addition enable the renewable energy systems to provide the appropriate support to the grid under balanced and unbalanced grid faults....

  17. Electromagnetic Landscape

    DEFF Research Database (Denmark)

    Cermak, Daniel; Okutsu, Ayaka; Jørgensen, Stina Marie Hasse

    2015-01-01

    Daniel Cermak-Sassenrath, Ayaka Okutsu, Stina Hasse. Electromagnetic Landscape - In-between Signal, Noise and Environment. Installation and artist talk. 21th International Symposium on Electronic Art (ISEA) 2015, Vancouver, CAN, Aug 14-18, 2015.......Daniel Cermak-Sassenrath, Ayaka Okutsu, Stina Hasse. Electromagnetic Landscape - In-between Signal, Noise and Environment. Installation and artist talk. 21th International Symposium on Electronic Art (ISEA) 2015, Vancouver, CAN, Aug 14-18, 2015....

  18. Nordic Landscape

    DEFF Research Database (Denmark)

    Hjortshøj, Rasmus

    2017-01-01

    This Box Set NORDIC LANDSCAPE presents Nordic Territories, a project by Rasmus Hjortshøj, exploring the man-made landscapes of the coastal territories and the entanglement of society and nature in times where it is no longer merely mankind subjected to nature, but where nature is equally being sh...... territories is not only their transient nature, but also the warm currents of the Gulf Stream making these northern shorelines habitable for human settlements....

  19. Operation of a Wind Turbine-Flywheel Energy Storage System under Conditions of Stochastic Change of Wind Energy

    OpenAIRE

    Tomczewski, Andrzej

    2014-01-01

    The paper presents the issues of a wind turbine-flywheel energy storage system (WT-FESS) operation under real conditions. Stochastic changes of wind energy in time cause significant fluctuations of the system output power and as a result have a negative impact on the quality of the generated electrical energy. In the author’s opinion it is possible to reduce the aforementioned effects by using an energy storage of an appropriate type and capacity. It was assumed that based on the technical pa...

  20. Free-Energy Landscape of Reverse tRNA Translocation through the Ribosome Analyzed by Electron Microscopy Density Maps and Molecular Dynamics Simulations

    Science.gov (United States)

    Ishida, Hisashi; Matsumoto, Atsushi

    2014-01-01

    To understand the mechanism of reverse tRNA translocation in the ribosome, all-atom molecular dynamics simulations of the ribosome-tRNAs-mRNA-EFG complex were performed. The complex at the post-translocational state was directed towards the translocational and pre-translocational states by fitting the complex into cryo-EM density maps. Between a series of the fitting simulations, umbrella sampling simulations were performed to obtain the free-energy landscape. Multistep structural changes, such as a ratchet-like motion and rotation of the head of the small subunit were observed. The free-energy landscape showed that there were two main free-energy barriers: one between the post-translocational and intermediate states, and the other between the pre-translocational and intermediate states. The former corresponded to a clockwise rotation, which was coupled to the movement of P-tRNA over the P/E-gate made of G1338, A1339 and A790 in the small subunit. The latter corresponded to an anticlockwise rotation of the head, which was coupled to the location of the two tRNAs in the hybrid state. This indicates that the coupled motion of the head rotation and tRNA translocation plays an important role in opening and closing of the P/E-gate during the ratchet-like movement in the ribosome. Conformational change of EF-G was interpreted to be the result of the combination of the external motion by L12 around an axis passing near the sarcin-ricin loop, and internal hinge-bending motion. These motions contributed to the movement of domain IV of EF-G to maintain its interaction with A/P-tRNA. PMID:24999999

  1. Interactions of landscape disturbances and climate change dictate ecological pattern and process: spatial modeling of wildfire, insect, and disease dynamics under future climates

    Science.gov (United States)

    Rachel A. Loehman; Robert E. Keane; Lisa M. Holsinger; Zhiwei Wu

    2017-01-01

    Context: Interactions among disturbances, climate, and vegetation influence landscape patterns and ecosystem processes. Climate changes, exotic invasions, beetle outbreaks, altered fire regimes, and human activities may interact to produce landscapes that appear and function beyond historical analogs. Objectives We used the mechanistic...

  2. Landscape-and regional-scale shifts in forest composition under climate change in the Central Hardwood Region of the United States

    Science.gov (United States)

    Wen J. Wang; Hong S. He; Frank R. Thompson; Jacob S. Fraser; William D. Dijak

    2016-01-01

    Tree species distribution and abundance are affected by forces operating at multiple scales. Niche and biophysical process models have been commonly used to predict climate change effects at regional scales, however, these models have limited capability to include site-scale population dynamics and landscape- scale disturbance and dispersal. We applied a landscape...

  3. Changing Landscapes, Changing Landscape's Story

    Czech Academy of Sciences Publication Activity Database

    Lapka, Miloslav; Cudlínová, Eva

    2003-01-01

    Roč. 28, č. 3 (2003), s. 323-328 ISSN 0142-6397. [Symposium on Sustainable Landscapes in an Enlarged Europe. Nové Hrady, 12.09.2001-14.09.2001] R&D Projects: GA MŠk ME 530 Grant - others:GA-(XE) QLK5-CT-2000-01211-SPRITE Institutional research plan: CEZ:AV0Z5039906 Keywords : Landscape stability * narrative approach * socio-economic typology Subject RIV: DO - Wilderness Conservation

  4. Relationship of Energy Growth to Economic Growth under Alternative Energy Policies

    Energy Technology Data Exchange (ETDEWEB)

    Behling, Jr., D. J.; Dullien, R.; Hudson, E.

    1976-03-01

    This report is the first of a series of studies that will analyze the economic and social impacts of research, development, and demonstration plans of the Energy Research and Development Administration. Two policy proposals were examined against a Base Case set of economic and energy projections for the years 1985, 1990, and 2000: (1) the introduction of RD and D-initiated energy supply and end-use conversion technologies to expand domestic energy supply and to improve the efficiency and flexibility of its use; and (2) the imposition of taxes and tariffs on petroleum and natural gas to reduce demand for these primary energy sources. Targets for the amounts of imports of oil and gas were specified by ERDA as follows: 10 percent (or less) of total U.S. energy consumption in 1985; 8 percent (or less) of total U.S. energy consumption in 1990; and 5 percent (or less) of total U.S. energy consumption in 2000. The purpose of the analysis was to first identify the degree to which the introduction of new energy technologies and/or the imposition of energy taxes could reduce oil and gas imports toward the target levels; and second, to estimate the effects of these policies on the economy and the environment. These economic and environmental effects are thus a measure of the costs associated with meeting the import targets. The benefits of these policies, in the form of increased economic and political security were not measured. The analysis was based on an analytic framework which linked detailed mathematical process engineering and economic models to more aggregate econometric models. The four models employed are described.

  5. ENERGY USE PATTERN IN VEGETABLE PRODUCTION UNDER FADAMA IN NORTH CENTRAL NIGERIA

    Directory of Open Access Journals (Sweden)

    Hussaini Yusuf Ibrahim

    2011-10-01

    Full Text Available The aim of this research was to examine the energy use pattern, energy use efficiency and energy productivity for vegetable production under Fadama or the seasonally flooded or floodable plains along major savanna rivers in north central Nigeria. To achieve these objectives, the data for the production of four major vegetables produced under Fadama (Onion, Tomato, Sweet and Hot Pepper were collected from 192 Fadama farmers. The results show that Tomato production was the most energy intensive among the four vegetables investigated. For all the vegetables, the usage of non-renewable energy inputs such as petrol and urea fertilizer was quite substantial as such, the efficiency of energy use and energy productivity were very low. The energy use efficiency were, 0.20, 0.10, 0.10 and 0.06, while the energy productivity were 0.25, 0.12, 0.13 and 0.07 for Onion, Tomato, Sweet and Hot Pepper respectively. However, to enhance the energy use efficiency and energy productivity of the system, the usage of renewable energy inputs especially organic manure should be promoted. In addition, energy efficient water pumps should be introduced into the Fadama communities.

  6. Measuring energy efficiency under heterogeneous technologies using a latent class stochastic frontier approach: An application to Chinese energy economy

    International Nuclear Information System (INIS)

    Lin, Boqiang; Du, Kerui

    2014-01-01

    The importance of technology heterogeneity in estimating economy-wide energy efficiency has been emphasized by recent literature. Some studies use the metafrontier analysis approach to estimate energy efficiency. However, for such studies, some reliable priori information is needed to divide the sample observations properly, which causes a difficulty in unbiased estimation of energy efficiency. Moreover, separately estimating group-specific frontiers might lose some common information across different groups. In order to overcome these weaknesses, this paper introduces a latent class stochastic frontier approach to measure energy efficiency under heterogeneous technologies. An application of the proposed model to Chinese energy economy is presented. Results show that the overall energy efficiency of China's provinces is not high, with an average score of 0.632 during the period from 1997 to 2010. - Highlights: • We introduce a latent class stochastic frontier approach to measure energy efficiency. • Ignoring technological heterogeneity would cause biased estimates of energy efficiency. • An application of the proposed model to Chinese energy economy is presented. • There is still a long way for China to develop an energy efficient regime

  7. Altered metabolic landscape in IDH-mutant gliomas affects phospholipid, energy, and oxidative stress pathways.

    Science.gov (United States)

    Fack, Fred; Tardito, Saverio; Hochart, Guillaume; Oudin, Anais; Zheng, Liang; Fritah, Sabrina; Golebiewska, Anna; Nazarov, Petr V; Bernard, Amandine; Hau, Ann-Christin; Keunen, Olivier; Leenders, William; Lund-Johansen, Morten; Stauber, Jonathan; Gottlieb, Eyal; Bjerkvig, Rolf; Niclou, Simone P

    2017-12-01

    Heterozygous mutations in NADP-dependent isocitrate dehydrogenases (IDH) define the large majority of diffuse gliomas and are associated with hypermethylation of DNA and chromatin. The metabolic dysregulations imposed by these mutations, whether dependent or not on the oncometabolite D-2-hydroxyglutarate (D2HG), are less well understood. Here, we applied mass spectrometry imaging on intracranial patient-derived xenografts of IDH-mutant versus IDH wild-type glioma to profile the distribution of metabolites at high anatomical resolution in situ This approach was complemented by in vivo tracing of labeled nutrients followed by liquid chromatography-mass spectrometry (LC-MS) analysis. Selected metabolites were verified on clinical specimen. Our data identify remarkable differences in the phospholipid composition of gliomas harboring the IDH1 mutation. Moreover, we show that these tumors are characterized by reduced glucose turnover and a lower energy potential, correlating with their reduced aggressivity. Despite these differences, our data also show that D2HG overproduction does not result in a global aberration of the central carbon metabolism, indicating strong adaptive mechanisms at hand. Intriguingly, D2HG shows no quantitatively important glucose-derived label in IDH-mutant tumors, which suggests that the synthesis of this oncometabolite may rely on alternative carbon sources. Despite a reduction in NADPH, glutathione levels are maintained. We found that genes coding for key enzymes in de novo glutathione synthesis are highly expressed in IDH-mutant gliomas and the expression of cystathionine-β-synthase ( CBS ) correlates with patient survival in the oligodendroglial subtype. This study provides a detailed and clinically relevant insight into the in vivo metabolism of IDH1-mutant gliomas and points to novel metabolic vulnerabilities in these tumors. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

  8. The Energy Effectiveness Of Crops In Crop Rotation Under Different Soil Tillage Systems

    Directory of Open Access Journals (Sweden)

    Strašil Zdeněk

    2015-09-01

    Full Text Available The paper identifies and compares the energy balance of winter wheat, spring barley and white mustard – all grown in crop rotation under different tillage conditions. The field trial included the conventional tillage (CT method, minimum tillage (MT and a system with no tillage (NT. The energy inputs included both the direct and indirect energy component. Energy outputs are evaluated as gross calorific value (gross heating value of phytomass dry matter of the primary product and the total harvested production. The energy effectiveness (energy output: energy input was selected for evaluation. The greatest energy effectiveness for the primary product was established as 6.35 for barley, 6.04 for wheat and 3.68 for mustard; in the case of total production, it was 9.82 for barley, 10.08 for wheat and 9.72 for mustard. When comparing the different tillage conditions, the greatest energy effectiveness was calculated for the evaluated crops under the MT operation and represented the primary product of wheat at 6.49, barley at 6.69 and mustard at 3.92. The smallest energy effectiveness for the primary product was found in wheat 5.77 and barley 6.10 under the CT option; it was 3.55 for mustard under the option of NT. Throughout the entire cropping pattern, the greatest energy effectiveness was established under the minimum tillage option – 5.70 for the primary product and 10.47 for the total production. On the other hand, the smallest values were calculated under CT – 5.22 for the primary product and 9.71 for total production.

  9. THE METHODOLOGY OF VALORISING AND ASSESSING LANDSCAPE

    Directory of Open Access Journals (Sweden)

    Stanisław Jacek Bacior

    2017-01-01

    Full Text Available Landscape evaluation process requires access to particular information resources making it possible to regionalize (divide into zones the area under investigation. Thus, the starting point is landscape assessment and evaluation followed by regionalization. As a result of this step, we determine certain areas that are homogenous with regards to their landscape assets Keywords: assessing landscape, structure of rural areas, spatial planning of rural areas.

  10. Collaboration on Renewable Energy Standards, Testing, and Certification under the U.S. China Renewable Energy Partnership: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, W.; Kurtz, S.; Lin, W.

    2012-06-01

    During November 2009, the U.S. China Renewable Energy Partnership agreement was authorized in Beijing by Presidents Obama and Hu from the U.S. and China. One of the principle tasks under this new program is the collaboration of the U.S. and China on the topic of renewable energy standards, testing, and certification with an initial focus on solar PV and wind topics. This paper will describe and discuss the activities which have taken place under the bilateral collaboration to date.

  11. A coupled remote sensing and the Surface Energy Balance with Topography Algorithm (SEBTA) to estimate actual evapotranspiration under complex terrain

    Science.gov (United States)

    Gao, Z. Q.; Liu, C. S.; Gao, W.; Chang, N. B.

    2010-07-01

    Evapotranspiration (ET) may be used as an ecological indicator to address the ecosystem complexity. The accurate measurement of ET is of great significance for studying environmental sustainability, global climate changes, and biodiversity. Remote sensing technologies are capable of monitoring both energy and water fluxes on the surface of the Earth. With this advancement, existing models, such as SEBAL, S_SEBI and SEBS, enable us to estimate the regional ET with limited temporal and spatial scales. This paper extends the existing modeling efforts with the inclusion of new components for ET estimation at varying temporal and spatial scales under complex terrain. Following a coupled remote sensing and surface energy balance approach, this study emphasizes the structure and function of the Surface Energy Balance with Topography Algorithm (SEBTA). With the aid of the elevation and landscape information, such as slope and aspect parameters derived from the digital elevation model (DEM), and the vegetation cover derived from satellite images, the SEBTA can fully account for the dynamic impacts of complex terrain and changing land cover in concert with some varying kinetic parameters (i.e., roughness and zero-plane displacement) over time. Besides, the dry and wet pixels can be recognized automatically and dynamically in image processing thereby making the SEBTA more sensitive to derive the sensible heat flux for ET estimation. To prove the application potential, the SEBTA was carried out to present the robust estimates of 24 h solar radiation over time, which leads to the smooth simulation of the ET over seasons in northern China where the regional climate and vegetation cover in different seasons compound the ET calculations. The SEBTA was validated by the measured data at the ground level. During validation, it shows that the consistency index reached 0.92 and the correlation coefficient was 0.87.

  12. Landscape dynamics in Mediterranean oak forests under global change: understanding the role of anthropogenic and environmental drivers across forest types.

    Science.gov (United States)

    Acácio, Vanda; Dias, Filipe S; Catry, Filipe X; Rocha, Marta; Moreira, Francisco

    2017-03-01

    The Mediterranean region is projected to be extremely vulnerable to global change, which will affect the distribution of typical forest types such as native oak forests. However, our understanding of Mediterranean oak forest responses to future conditions is still very limited by the lack of knowledge on oak forest dynamics and species-specific responses to multiple drivers. We compared the long-term (1966-2006) forest persistence and land cover change among evergreen (cork oak and holm oak) and deciduous oak forests and evaluated the importance of anthropogenic and environmental drivers on observed changes for Portugal. We used National Forest Inventories to quantify the changes in oak forests and explored the drivers of change using multinomial logistic regression analysis and an information theoretical approach. We found distinct trends among oak forest types, reflecting the differences in oak economic value, protection status and management schemes: cork oak forests were the most persistent (62%), changing mostly to pines and eucalypt; holm oak forests were less persistent (53.2%), changing mostly to agriculture; and deciduous oak forests were the least persistent (45.7%), changing mostly to shrublands. Drivers of change had distinct importance across oak forest types, but drivers from anthropogenic origin (wildfires, population density, and land accessibility) were always among the most important. Climatic extremes were also important predictors of oak forest changes, namely extreme temperatures for evergreen oak forests and deficit of precipitation for deciduous oak forests. Our results indicate that under increasing human pressure and forecasted climate change, evergreen oak forests will continue declining and deciduous oak forests will be replaced by forests dominated by more xeric species. In the long run, multiple disturbances may change competitive dominance from oak forests to pyrophytic shrublands. A better understanding of forest dynamics and the

  13. Energy from biomass. Ethics and practice; Energie aus Biomasse. Ethik und Praxis

    Energy Technology Data Exchange (ETDEWEB)

    Franke, Silke (ed.)

    2013-06-01

    The implementation of the energy policy turnaround inevitably results in modifications of the land use and landscape. Besides the discussion about the environmental consequences, a debate about ethical issues increasingly arose. Under this aspect, the booklet under consideration contains the following contributions: (1) Renewable energy sources - the role of bioenergy (Bernard Widmann); (2) Energy from biomass - An ethic analysis (Stephan Schleissing); (3) Culture for our landscapes - combination of biomass and water protection (Frank Wagener); (4) Cultivation of energy crops - short rotation coppices (Frank Burger); (5) Bioenergy region Straubing-Bogen: Excellent in the matter of renewable energy sources (Josefine Eichwald); (6) Rural development - motor for the energy policy turnaround (Roland Spiller).

  14. Testing the rationality of DOE's energy price forecasts under asymmetric loss preferences

    International Nuclear Information System (INIS)

    Mamatzakis, E.; Koutsomanoli-Filippaki, A.

    2014-01-01

    This paper examines the rationality of the price forecasts for energy commodities of the United States Department of Energy's (DOE), departing from the common assumption in the literature that DOE's forecasts are based on a symmetric underlying loss function with respect to positive vs. negative forecast errors. Instead, we opt for the methodology of Elliott et al. (2005) that allows testing the joint hypothesis of an asymmetric loss function and rationality and reveals the underlying preferences of the forecaster. Results indicate the existence of asymmetries in the shape of the loss function for most energy categories with preferences leaning towards optimism. Moreover, we also examine whether there is a structural break in those preferences over the examined period, 1997–2012. - Highlights: • Examine the rationality of DOE energy forecasts. • Departing from a symmetric underlying loss function. • Asymmetries exist in most energy prices. • Preferences lean towards optimism. • Examine structural breaks in those preferences

  15. Energy Management Optimization for Cellular Networks under Renewable Energy Generation Uncertainty

    KAUST Repository

    Rached, Nadhir B.

    2017-03-28

    The integration of renewable energy (RE) as an alternative power source for cellular networks has been deeply investigated in literature. However, RE generation is often assumed to be deterministic; an impractical assumption for realistic scenarios. In this paper, an efficient energy procurement strategy for cellular networks powered simultaneously by the smart grid (SG) and locally deployed RE sources characterized by uncertain processes is proposed. For a one-day operation cycle, the mobile operator aims to reduce its total energy cost by optimizing the amounts of energy to be procured from the local RE sources and SG at each time period. Additionally, it aims to determine the amount of extra generated RE to be sold back to SG. A chance constrained optimization is first proposed to deal with the RE generation uncertainty. Then, two convex approximation approaches: Chernoff and Chebyshev methods, characterized by different levels of knowledge about the RE generation, are developed to determine the energy procurement strategy for different risk levels. In addition, their performances are analyzed for various daily scenarios through selected simulation results. It is shown that the higher complex Chernoff method outperforms the Chebyshev one for different risk levels set by the operator.

  16. Electromagnetic Landscape

    DEFF Research Database (Denmark)

    Cermak, Daniel; Okutsu, Ayaka; Hasse, Stina

    2015-01-01

    Electromagnetic Landscape demonstrates in direct, tangible and immediate ways effects of the disruption of the familiar. An ubiquitous technological medium, FM radio, is turned into an alien and unfamiliar one. Audience participation, the environment, radio signals and noise create a site......-specific, ragged sonic landscape. The work exhibits intrinsic, non-trivial, emerging behaviour, cyclic or wave-like, which converges and ebbs. It varies its sonic and visual display through a dynamic interaction of light sources, fog and light sensors. The system maintains a fluxing state of ambivalence between...

  17. An Online Landscape Object Library to Support Interactive Landscape Planning

    Directory of Open Access Journals (Sweden)

    Pang Chan

    2011-12-01

    Full Text Available Using landscape objects with geo-visualisation tools to create 3D virtual environments is becoming one of the most prominent communication techniques to understand landscape form, function and processes. Geo-visualisation tools can also provide useful participatory planning support systems to explore current and future environmental issues such as biodiversity loss, crop failure, competing pressures on water availability and land degradation. These issues can be addressed by understanding them in the context of their locality. In this paper we discuss some of the technologies which facilitate our work on the issues of sustainability and productivity, and ultimately support for planning and decision-making. We demonstrate an online Landscape Object Library application with a suite of geo-visualisation tools to support landscape planning. This suite includes: a GIS based Landscape Constructor tool, a modified version of a 3D game engine SIEVE (Spatial Information Exploration and Visualisation Environment and an interactive touch table display. By integrating the Landscape Object Library with this suite of geo-visualisation tools, we believe we developed a tool that can support a diversity of landscape planning activities. This is illustrated by trial case studies in biolink design, whole farm planning and renewable energy planning. We conclude the paper with an evaluation of our Landscape Object Library and the suite of geographical tools, and outline some further research directions.

  18. Simulating Everglades Carbon Fluxes and GHG Emission of Different Landscapes Under Present and Future Climate Conditions by Applying Community Land Model

    Science.gov (United States)

    Liao, Y.; Gerber, S.

    2016-12-01

    Carbon flux in wetland distinguishes from that in other types of ecosystems due to special soil and hydrological processes. Understanding the dynamic of soil hydrology is necessary to explore the responses of the plants, the fate of massive carbon storage and greenhouse gas emissions under different climate conditions. However, contrary findings were published regarding the relationship between CO2 emission and water level variations. Both positive and negative conclusions were reached regarding the warming mitigation ability of wetland. By parameterizing the Community Land Model (CLM), our research focuses on simulating the CO2/CH4 fluxes of different landscapes in Everglades, a subtropical wetland in Florida, to explore the following questions: 1) Is it a sink or source for CO2? 2) How may the CO2/CH4 dynamics be altered with water table and soil water content? 3) What environmental factors mainly control CO2/CH4 process? 4) Does this ecosystem contribute or mitigate cliamte warming? 5) What is the difference between landscapes regarding the CO2/CH4 dynamic? We performed several simulations with CLM that address the variation of water table in soil layers and the elevated temperature to compare the impact on the carbon fluxes and GHG emission in the study area. Our results suggest the variation on water table depth has significant influence on the carbon cycle in Everglades. Deeper water table results in a higher CO2 but lower CH4 emission, partly due to the CH4 oxidization and the rapid decomposition of organic carbon. In the wet season, more CH4 is produced when the water table is shallower. Slightly elevated temperature causes a water loss through evapotranspiration which deepens the water table. However, the induced carbon loss is partly offset by the enhanced productivity of vegetation. Both long and short hydroperiod marshes are small carbon sinks in most of years but cannot mitigate the climate warming if considering CH4 emissions. Cypress swamp shows high

  19. Advanced Thermal Energy Conversion of Temperature under 300°C by Thermoelectric Conversion Method

    Science.gov (United States)

    Ueda, Tadashi; Uchida, Yoshiyuki; Shingu, Hiroyasu

    Many approaches have been developing for energy conversion throughout the world. However, it is difficult to achieve the global warming countermeasure based on “The Kyoto protocol”. Until now effective utilization of low temperature thermal energy (under 300°C) is not advancing one. For example, effective utilization method has not been established for waste heat energy which arise from industry machine tools, automobiles, internal combustion engines and thermal energy from natural environment, etc. In this paper, we reported the experiment for effective utilizing of low temperature (under 300°C) thermal energy conversion. The device used for the measurement is a copper thermo device. Thermo electromotive force of 150mW/cm2 was obtained at 200°C. The obtained thermo electromotive force is about 15 times higher in comparison with generally used alumal-chromal thermocouple. Our aim is that utilizes low temperature thermal energy effectively by converting into electricity.

  20. Universal time-dependence of the mean-square displacement in extremely rugged energy landscapes with equal minima

    DEFF Research Database (Denmark)

    Dyre, Jeppe; Jacobsen, Jacob M.

    1995-01-01

    This paper presents a calculation of the time dependence of the mean-square displacement for symmetric random energy barrier hopping models at low temperatures, where the frequency dependence of the normalized diffusion constant D-tilde becomes universal, i.e., independent of the energy barrier p...

  1. TFAP2B influences the effect of dietary fat on weight loss under energy restriction

    DEFF Research Database (Denmark)

    Stocks, Tanja; Angquist, Lars; Banasik, Karina

    2012-01-01

    Numerous gene loci are related to single measures of body weight and shape. We investigated if 55 SNPs previously associated with BMI or waist measures, modify the effects of fat intake on weight loss and waist reduction under energy restriction.......Numerous gene loci are related to single measures of body weight and shape. We investigated if 55 SNPs previously associated with BMI or waist measures, modify the effects of fat intake on weight loss and waist reduction under energy restriction....

  2. Wildlife Population Dynamics in Human-Dominated Landscapes under Community-Based Conservation: The Example of Nakuru Wildlife Conservancy, Kenya.

    Science.gov (United States)

    Ogutu, Joseph O; Kuloba, Bernard; Piepho, Hans-Peter; Kanga, Erustus

    2017-01-01

    increased overall whereas that of herbivores first increased from 1996 to 2006 and then levelled off thereafter. Aggregate herbivore biomass increased linearly with increasing cumulative wet season rainfall. The densities of the 30 most abundant species were either strongly positively or negatively correlated with cumulative past rainfall, most commonly with the early wet season component. The collaborative wildlife conservation and management initiatives undertaken on the mosaic of private, communal and public lands were thus associated with increase or no decrease in numbers of 32 and decrease in numbers of 12 of the 44 species. Despite the decline by some species, effective community-based conservation is central to the future of wildlife in the NWC and other rangelands of Kenya and beyond and is crucially dependent on the good will, effective engagement and collective action of local communities, working in partnerships with various organizations, which, in NWC, operated under the umbrella of the Nakuru Wildlife Forum.

  3. Wildlife Population Dynamics in Human-Dominated Landscapes under Community-Based Conservation: The Example of Nakuru Wildlife Conservancy, Kenya.

    Directory of Open Access Journals (Sweden)

    Joseph O Ogutu

    carnivores increased overall whereas that of herbivores first increased from 1996 to 2006 and then levelled off thereafter. Aggregate herbivore biomass increased linearly with increasing cumulative wet season rainfall. The densities of the 30 most abundant species were either strongly positively or negatively correlated with cumulative past rainfall, most commonly with the early wet season component. The collaborative wildlife conservation and management initiatives undertaken on the mosaic of private, communal and public lands were thus associated with increase or no decrease in numbers of 32 and decrease in numbers of 12 of the 44 species. Despite the decline by some species, effective community-based conservation is central to the future of wildlife in the NWC and other rangelands of Kenya and beyond and is crucially dependent on the good will, effective engagement and collective action of local communities, working in partnerships with various organizations, which, in NWC, operated under the umbrella of the Nakuru Wildlife Forum.

  4. Electron energy spectrum and maximum disruption angle under multi-photon beamstrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Yokoya, Kaoru; Chen, Pisin

    1989-03-01

    The final electron energy spectrum under multi-photon beamstrahlung process is derived analytically in the classical and the intermediate regimes. The maximum disruption angle from the low energy tail of the spectrum is also estimated. The results are then applied to the TLC and the CLIC parameters. 6 refs., 1 fig., 1 tab.

  5. Quasi-emf under contact interaction of bodies during cutting as electron potential energy measurement

    International Nuclear Information System (INIS)

    Vasil'ev, S.V.

    1989-01-01

    It is shown that cutting quasi-emf measured under the contact interaction of a number of pure metals (molybdenum, titanium, niobium, iron, copper, beryllium, lead, nickel and cobalt), graphite and silicon correlates closely with Fermi levels calculated for them, i.e. it reflects the potential electron energy. Correlation is observed at different cutting rate (temperature) and consequently at different electron kinetic energy

  6. 29 CFR Appendix A to Part 24 - Your Rights Under the Energy Reorganization Act

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Your Rights Under the Energy Reorganization Act A Appendix A to Part 24 Labor Office of the Secretary of Labor PROCEDURES FOR THE HANDLING OF RETALIATION... the Energy Reorganization Act ER10AU07.000 ...

  7. Returns on investments in energy-saving technologies under energy price uncertainty in Dutch greenhouse horticulture

    NARCIS (Netherlands)

    Diederen, P.J.M.; Tongeren, van F.W.; Veen, van der H.B.

    2003-01-01

    Conventional net present value calculations evaluating the profitability of investments in energy-saving technologies in Dutch horticultural outlays predict a much higher rate of adoption of these technologies than is actually observed. This paper tries to explain this gap by applying a real options

  8. Disposable Landscapes

    Science.gov (United States)

    Kevin T. Smith

    2008-01-01

    Whether we are a traditionalist or on the cutting edge of landscape care, we need to take a deep breath and think about what we are trying to achieve, before we select a specific treatment or practice for tree care. We should measure that treatment or practice against what we know about the tree system. I say "system" because the recent years of Modern...

  9. Effects of Home Energy Management Systems on Distribution Utilities and Feeders Under Various Market Structure; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, M.; Pratt, A.; Lunacek, M.; Mittal, S.; Wu, H.; Jones, W.

    2015-06-15

    The combination of distributed energy resources (DER) and retail tariff structures to provide benefits to both utility consumers and the utilities is not well understood. To improve understanding, an Integrated Energy System Model (IESM) is being developed to simulate the physical and economic aspects of DER technologies, the buildings where they reside, and feeders servicing them. The IESM was used to simulate 20 houses with home energy management systems on a single feeder under a time-of-use (TOU) tariff to estimate economic and physical impacts on both the households and the distribution utilities. Home energy management systems (HEMS) reduce consumers’ electric bills by precooling houses in the hours before peak electricity pricing. Utilization of HEMS reduce peak loads during high price hours but shifts it to hours with off-peak and shoulder prices, resulting in a higher peak load. used to simulate 20 houses with home energy management systems on a single feeder under a time-of-use (TOU) tariff to estimate economic and physical impacts on both the households and the distribution utilities. Home energy management systems (HEMS) reduce consumers’ electric bills by precooling houses in the hours before peak electricity pricing. Utilization of HEMS reduce peak loads during high price hours but shifts it to hours with off-peak and shoulder prices, resulting in a higher peak load.

  10. A study of the deep structure of the energy landscape of glassy polystyrene: the exponential distribution of the energy barriers revealed by high-field electron spin resonance spectroscopy

    International Nuclear Information System (INIS)

    Bercu, V; Martinelli, M; Massa, C A; Pardi, L A; Leporini, D

    2004-01-01

    The reorientation of one small paramagnetic molecule (spin probe) in glassy polystyrene (PS) is studied by high-field electron spin resonance spectroscopy at two different Larmor frequencies (190 and 285 GHz). The exponential distribution of the energy barriers for the rotational motion of the spin probe is unambiguously evidenced at both 240 and 270 K. The same shape for the distribution of the energy barriers of PS was evidenced by the master curves provided by previous mechanical and light scattering studies. The breadth of the energy barrier distribution of the spin probe is in the range of the estimates of the breadth of the PS energy barrier distribution. The evidence that the deep structure of the energy landscape of PS exhibits the exponential shape of the energy barrier distribution agrees with the results from extreme-value statistics (Bouchaud and Mezard 1997 J. Phys. A: Math. Gen. 30 7997) and the trap model by Bouchaud and co-workers (1996 J. Phys. A: Math. Gen. 29 3847, 2001 Phys. Rev. B 64 104417). (letter to the editor)

  11. Theoretical analysis, infrared and structural investigations of energy dissipation in metals under cyclic loading

    International Nuclear Information System (INIS)

    Plekhov, O.A.; Saintier, N.; Palin-Luc, T.; Uvarov, S.V.; Naimark, O.B.

    2007-01-01

    The infrared and structural investigations of energy dissipation processes in metals subjected to cyclic loading have given impetus to the development of a new thermodynamic model with the capability of describing the energy balance under plastic deformation. The model is based on the statistical description of the mesodefect ensemble evolution and its influence on the dissipation ability of the material. Constitutive equations have been formulated for plastic and structural strains, which allow us to describe the stored and dissipated parts of energy under plastic flow. Numerical results indicate that theoretical predictions are in good agreement with the experimentally observed temperature data

  12. Under- and Over-Reporting of Energy Intake in Slovenian Adolescents

    Science.gov (United States)

    Kobe, Helena; Krzisnik, Ciril; Mis, Natasa Fidler

    2012-01-01

    Objective: To examine under- and over-reporting of energy intake (EI) among adolescents and to compare relative food and nutrient intakes of under-reporters (UR), over-reporters (OR), and the whole population to acceptable reporters (AR). Design: All adolescents completed food frequency questionnaires at regional health centers, and a subgroup…

  13. Ecological Functions of Landscapes

    Science.gov (United States)

    Kiryushin, V. I.

    2018-01-01

    Ecological functions of landscapes are considered a system of processes ensuring the development, preservation, and evolution of ecosystems and the biosphere as a whole. The concept of biogeocenosis can be considered a model that integrates biotic and environmental functions. The most general biogeocenotic functions specify the biodiversity, biotic links, self-organization, and evolution of ecosystems. Close interaction between biocenosis and the biotope (ecotope) is ensured by the continuous exchange of matter, energy, and information. Ecotope determines the biocenosis. The group of ecotopic functions includes atmospheric (gas exchange, heat exchange, hydroatmospheric, climate-forming), lithospheric (geodynamic, geophysical, and geochemical), hydrologic and hydrogeologic functions of landscape and ecotopic functions of soils. Bioecological functions emerge as a result of the biotope and ecotope interaction; these are the bioproductive, destructive, organoaccumulative, biochemical (gas, concentration, redox, biochemical, biopedological), pedogenetic, and energy functions

  14. An approach to costs and energy consumption in private urban Spanish Mediterranean landscapes from a simplified model in sprinkle irrigation

    Directory of Open Access Journals (Sweden)

    G. Arbat

    2013-02-01

    Full Text Available The number of private gardens has increased in recent years, creating a more pleasant urban model, but not without having an environmental impact, including increased energy consumption, which is the focus of this study. The estimation of costs and energy consumption for the generic typology of private urban gardens is based on two simplifying assumptions: square geometry with surface areas from 25 to 500 m2 and hydraulic design with a single pipe. In total, eight sprinkler models have been considered, along with their possible working pressures, and 31 pumping units grouped into 5 series that adequately cover the range of required flow rates and pressures, resulting in 495 hydraulic designs repeated for two climatically different locations in the Spanish Mediterranean area (Girona and Elche. Mean total irrigation costs for the locality with lower water needs (Girona and greater needs (Elche were € 2,974 ha-1 yr-1 and € 3,383 ha-1 yr-1, respectively. Energy costs accounted for 11.4% of the total cost for the first location, and 23.0% for the second. While a suitable choice of the hydraulic elements of the setup is essential, as it may provide average energy savings of 77%, due to the low energy cost in relation to the cost of installation, the potential energy savings do not constitute a significant incentive for the irrigation system design. The low efficiency of the pumping units used in this type of garden is the biggest obstacle and constraint to achieving a high quality energy solution.

  15. An approach to costs and energy consumption in private urban Spanish Mediterranean landscapes from a simplified model in sprinkle irrigation

    Energy Technology Data Exchange (ETDEWEB)

    Arbat, G.; Pujol, J.; Pelegri, M.; Puig-Bargues, J.; Duran-Ros, M.; Ramirez de Cartagena, F.

    2013-05-01

    The number of private gardens has increased in recent years, creating a more pleasant urban model, but not without having an environmental impact, including increased energy consumption, which is the focus of this study. The estimation of costs and energy consumption for the generic typology of private urban gardens is based on two simplifying assumptions: square geometry with surface areas from 25 to 500 m{sup 2} and hydraulic design with a single pipe. In total, eight sprinkler models have been considered, along with their possible working pressures, and 31 pumping units grouped into 5 series that adequately cover the range of required flow rates and pressures, resulting in 495 hydraulic designs repeated for two climatically different locations in the Spanish Mediterranean area (Girona and Elche). Mean total irrigation costs for the locality with lower water needs (Girona) and greater needs (Elche) were {epsilon} 2,974 ha{sup -}1 yr-1 and {epsilon}3,383 ha{sup -}1 yr{sup -}1, respectively. Energy costs accounted for 11.4% of the total cost for the first location, and 23.0% for the second. While a suitable choice of the hydraulic elements of the setup is essential, as it may provide average energy savings of 77%, due to the low energy cost in relation to the cost of installation, the potential energy savings do not constitute a significant incentive for the irrigation system design. The low efficiency of the pumping units used in this type of garden is the biggest obstacle and constraint to achieving a high quality energy solution. (Author) 32 refs.

  16. The potential and flux landscape theory of evolution.

    Science.gov (United States)

    Zhang, Feng; Xu, Li; Zhang, Kun; Wang, Erkang; Wang, Jin

    2012-08-14

    We established the potential and flux landscape theory for evolution. We found explicitly the conventional Wright's gradient adaptive landscape based on the mean fitness is inadequate to describe the general evolutionary dynamics. We show the intrinsic potential as being Lyapunov function(monotonically decreasing in time) does exist and can define the adaptive landscape for general evolution dynamics for studying global stability. The driving force determining the dynamics can be decomposed into gradient of potential landscape and curl probability flux. Non-zero flux causes detailed balance breaking and measures how far the evolution from equilibrium state. The gradient of intrinsic potential and curl flux are perpendicular to each other in zero fluctuation limit resembling electric and magnetic forces on electrons. We quantified intrinsic energy, entropy and free energy of evolution and constructed non-equilibrium thermodynamics. The intrinsic non-equilibrium free energy is a Lyapunov function. Both intrinsic potential and free energy can be used to quantify the global stability and robustness of evolution. We investigated an example of three allele evolutionary dynamics with frequency dependent selection (detailed balance broken). We uncovered the underlying single, triple, and limit cycle attractor landscapes. We found quantitative criterions for stability through landscape topography. We also quantified evolution pathways and found paths do not follow potential gradient and are irreversible due to non-zero flux. We generalized the original Fisher's fundamental theorem to the general (i.e., frequency dependent selection) regime of evolution by linking the adaptive rate with not only genetic variance related to the potential but also the flux. We show there is an optimum potential where curl flux resulting from biotic interactions of individuals within a species or between species can sustain an endless evolution even if the physical environment is unchanged. We

  17. Greenhouse gas emissions of an agro-biogas energy system: Estimation under the Renewable Energy Directive.

    Science.gov (United States)

    Rana, Roberto; Ingrao, Carlo; Lombardi, Mariarosaria; Tricase, Caterina

    2016-04-15

    Agro-biogas from energy crops and by-products is a renewable energy carrier that can potentially contribute to climate change mitigation. In this context, application of the methodology defined by the Renewable Energy Directive 2009/28/EC (RED) was performed in order to estimate the 100-year Global Warming Potential (GWP100) associated with an agro-biogas supply chain (SC) in Southern Italy. Doing so enabled calculation of Greenhouse Gas (GHG) emission saving in order to verify if it is at least equal to 35% compared to the fossil fuel reference system, as specified by the RED. For the assessment, an attributional Life Cycle Assessment (LCA) approach (International Organization for Standardization (ISO), 2006a,b) was integrated with the RED methodology applied following the guidelines reported in COM(2010)11 and updated by SWD(2014)259 and Report EUR 27215 EN (2015). Moreover, primary data were collected with secondary data extrapolated from the Ecoinvent database system. Results showed that the GWP100 associated with electricity production through the biogas plant investigated was equal to 111.58gCO2eqMJe(-1) and so a 40.01% GHG-emission saving was recorded compared to the RED reference. The highest contribution comes from biomass production and, in particular, from crop cultivation due to production of ammonium nitrate in the overall amount used for crop cultivation. Based upon the findings of the study, the GHG saving calculated slightly exceeds the related minimum proposed by the RED: therefore, improvements are needed anyway. In particular, the authors documented that through replacement of ammonium nitrate with urea the GHG-emission saving would increase to almost 68%, thus largely satisfying the RED limit. In addition, the study highlighted that conservation practices, such as NT, can significantly enable reduction of the GHG-emissions coming from agricultural activities. Therefore, those practices should be increasingly adopted for cultivation of energy

  18. Greenhouse gas emissions of an agro-biogas energy system: Estimation under the Renewable Energy Directive

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Roberto, E-mail: roberto.rana@unifg.it; Ingrao, Carlo; Lombardi, Mariarosaria; Tricase, Caterina

    2016-04-15

    Agro-biogas from energy crops and by-products is a renewable energy carrier that can potentially contribute to climate change mitigation. In this context, application of the methodology defined by the Renewable Energy Directive 2009/28/EC (RED) was performed in order to estimate the 100-year Global Warming Potential (GWP{sub 100}) associated with an agro-biogas supply chain (SC) in Southern Italy. Doing so enabled calculation of Greenhouse Gas (GHG) emission saving in order to verify if it is at least equal to 35% compared to the fossil fuel reference system, as specified by the RED. For the assessment, an attributional Life Cycle Assessment (LCA) approach (International Organization for Standardization (ISO), 2006a,b) was integrated with the RED methodology applied following the guidelines reported in COM(2010)11 and updated by SWD(2014)259 and Report EUR 27215 EN (2015). Moreover, primary data were collected with secondary data extrapolated from the Ecoinvent database system. Results showed that the GWP{sub 100} associated with electricity production through the biogas plant investigated was equal to 111.58 g CO{sub 2eq} MJ{sub e}{sup −1} and so a 40.01% GHG-emission saving was recorded compared to the RED reference. The highest contribution comes from biomass production and, in particular, from crop cultivation due to production of ammonium nitrate in the overall amount used for crop cultivation. Based upon the findings of the study, the GHG saving calculated slightly exceeds the related minimum proposed by the RED: therefore, improvements are needed anyway. In particular, the authors documented that through replacement of ammonium nitrate with urea the GHG-emission saving would increase to almost 68%, thus largely satisfying the RED limit. In addition, the study highlighted that conservation practices, such as NT, can significantly enable reduction of the GHG-emissions coming from agricultural activities. Therefore, those practices should be increasingly

  19. The Associative Memory, Water Mediated, Structure and Energy Model (AWSEM)-Amylometer: Predicting Amyloid Propensity and Fibril Topology Using an Optimized Folding Landscape Model.

    Science.gov (United States)

    Chen, Mingchen; Schafer, Nicholas P; Zheng, Weihua; Wolynes, Peter G

    2018-01-10

    Amyloids are fibrillar protein aggregates with simple repeated structural motifs in their cores, usually β-strands but sometimes α-helices. Identifying the amyloid-prone regions within protein sequences is important both for understanding the mechanisms of amyloid-associated diseases and for understanding functional amyloids. Based on the crystal structures of seven cross-β amyloidogenic peptides with different topologies and one recently solved cross-α fiber structure, we have developed a computational approach for identifying amyloidogenic segments in protein sequences using the Associative memory, Water mediated, Structure and Energy Model (AWSEM). The AWSEM-Amylometer performs favorably in comparison with other predictors in predicting aggregation-prone sequences in multiple data sets. The method also predicts well the specific topologies (the relative arrangement of β-strands in the core) of the amyloid fibrils. An important advantage of the AWSEM-Amylometer over other existing methods is its direct connection with an efficient, optimized protein folding simulation model, AWSEM. This connection allows one to combine efficient and accurate search of protein sequences for amyloidogenic segments with the detailed study of the thermodynamic and kinetic roles that these segments play in folding and aggregation in the context of the entire protein sequence. We present new simulation results that highlight the free energy landscapes of peptides that can take on multiple fibril topologies. We also demonstrate how the Amylometer methodology can be straightforwardly extended to the study of functional amyloids that have the recently discovered cross-α fibril architecture.

  20. Influence of Go-like interactions on global shapes of energy landscapes in beta-barrel forming model proteins: inherent structure analysis and statistical temperature molecular dynamics simulation.

    Science.gov (United States)

    Kim, Jaegil; Keyes, Thomas

    2008-01-24

    Recently, the native-centric, coarse-grained "Go-like" protein model has gained a renewed popularity because of its computational simplicity and successful description of some key aspects of folding thermodynamics and kinetics. In the present paper, the properties of Go-like models are investigated in terms of the potential energy landscape (PEL). The non-native attractions of the beta-barrel forming BLN model 46-mer are scaled with a parameter 0 Go-like interactions brings about a significant modification in the occupation of low-lying IS by destabilizing the misfolding funnel into a higher energy region, strongly influencing the folding thermodynamics. The alteration of the PEL also induces a dramatic change in the folding mechanism, from a second-order-like collapse transition into a cooperative, first-order-like folding transition, occurring through a transient, intermediate state ensemble characterized by partially structured IS. The appearance of multiple van der Waals loops in the statistical temperature of the Go-like model is associated with the development of the intermediate states.

  1. Characterization of the polymer energy landscape in polymer:fullerene bulk heterojunctions with pure and mixed phases

    KAUST Repository

    Sweetnam, Sean

    2014-10-08

    Theoretical and experimental studies suggest that energetic offsets between the charge transport energy levels in different morphological phases of polymer:fullerene bulk heterojunctions may improve charge separation and reduce recombination in polymer solar cells (PSCs). In this work, we use cyclic voltammetry, UV-vis absorption, and ultraviolet photoelectron spectroscopy to characterize hole energy levels in the polymer phases of polymer:fullerene bulk heterojunctions. We observe an energetic offset of up to 150 meV between amorphous and crystalline polymer due to bandgap widening associated primarily with changes in polymer conjugation length. We also observe an energetic offset of up to 350 meV associated with polymer:fullerene intermolecular interactions. The first effect has been widely observed, but the second effect is not always considered despite being larger in magnitude for some systems. These energy level shifts may play a major role in PSC performance and must be thoroughly characterized for a complete understanding of PSC function.

  2. Characteristics of Crushing Energy and Fractal of Magnetite Ore under Uniaxial Compression

    Science.gov (United States)

    Gao, F.; Gan, D. Q.; Zhang, Y. B.

    2018-03-01

    The crushing mechanism of magnetite ore is a critical theoretical problem on the controlling of energy dissipation and machine crushing quality in ore material processing. Uniaxial crushing tests were carried out to research the deformation mechanism and the laws of the energy evolution, based on which the crushing mechanism of magnetite ore was explored. The compaction stage and plasticity and damage stage are two main compression deformation stages, the main transitional forms from inner damage to fracture are plastic deformation and stick-slip. In the process of crushing, plasticity and damage stage is the key link on energy absorption for that the specimen tends to saturate energy state approaching to the peak stress. The characteristics of specimen deformation and energy dissipation can synthetically reply the state of existed defects inner raw magnetite ore and the damage process during loading period. The fast releasing of elastic energy and the work done by the press machine commonly make raw magnetite ore thoroughly broken after peak stress. Magnetite ore fragments have statistical self-similarity and size threshold of fractal characteristics under uniaxial squeezing crushing. The larger ratio of releasable elastic energy and dissipation energy and the faster energy change rate is the better fractal properties and crushing quality magnetite ore has under uniaxial crushing.

  3. Landscape linkages and biodiversity in European landscapes

    NARCIS (Netherlands)

    Jongman, R.H.G.

    2004-01-01

    Linear features are structuring landscape elements. We change our landscapes and rebuild them into new linkages, and landscapes are even constructed around these linkages. Landscape linkages are important for species migration and dispersal on a large scale and a small scale: storks, bats and

  4. Agroforestry landscapes and global change: landscape ecology tools for management and conservation

    Science.gov (United States)

    Guillermo Martinez Pastur; Emilie Andrieu; Louis R. Iverson; Pablo Luis. Peri

    2012-01-01

    Forest ecosystems are impacted by multiple uses under the influence of global drivers, and where landscape ecology tools may substantially facilitate the management and conservation of the agroforestry ecosystems. The use of landscape ecology tools was described in the eight papers of the present special issue, including changes in forested landscapes due to...

  5. 10 CFR 70.11 - Persons using special nuclear material under certain Department of Energy and Nuclear Regulatory...

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Persons using special nuclear material under certain Department of Energy and Nuclear Regulatory Commission contracts. 70.11 Section 70.11 Energy NUCLEAR... using special nuclear material under certain Department of Energy and Nuclear Regulatory Commission...

  6. Optimization under uncertainty of a biomass-integrated renewable energy microgrid with energy storage

    DEFF Research Database (Denmark)

    Zheng, Yingying; Jenkins, Bryan M.; Kornbluth, Kurt

    2018-01-01

    Deterministic constrained optimization and stochastic optimization approaches were used to evaluate uncertainties in biomass-integrated microgrids supplying both electricity and heat. An economic linear programming model with a sliding time window was developed to assess design and scheduling of ...... structure, and technical and financial performance of the various components of the microgrid. Monte Carlo simulation was used to evaluate uncertainties in weather and economic assumptions, generating a probability density function for the cost of energy.......Deterministic constrained optimization and stochastic optimization approaches were used to evaluate uncertainties in biomass-integrated microgrids supplying both electricity and heat. An economic linear programming model with a sliding time window was developed to assess design and scheduling...

  7. Energy Saving Potential of PCMs in Buildings under Future Climate Conditions

    Directory of Open Access Journals (Sweden)

    Abdo Abdullah Ahmed Gassar

    2017-11-01

    Full Text Available Energy consumption reduction under changing climate conditions is a major challenge in buildings design, where excessive energy consumption creates an economic and environmental burden. Improving thermal performance of the buildings through support applying phase change material (PCM is a promising strategy for reducing building energy consumption under future climate change. Therefore, this study aims to investigate the energy saving potentials in buildings under future climate conditions in the humid and snowy regions in the hot continental and humid subtropical climates of the east Asia (Seoul, Tokyo and Hong Kong when various PCMs with different phase change temperatures are applied to a lightweight building envelope. Methodology in this work is implemented in two phases: firstly, investigation of energy saving potentials in buildings through inclusion of three types of PCMs with different phase temperatures into the building envelop separately and use weather file in the present (2017; and, secondly, evaluation of the effect of future climate change on the performance of PCMs by analyzing energy saving potentials of PCMs with 2020, 2050 and 2080 weather data. The results show that the inclusion of PCM into the building envelope is a promising strategy to increase the energy performance in buildings during both heating and cooling seasons in Seoul, Tokyo and Hong Kong under future climate conditions. The energy savings achieved by using PCMs in those regions are electricity savings of 4.48–8.21%, 3.81–9.69%, and 1.94–5.15%, and gas savings of 1.65–16.59%, 7.60–61.76%, and 62.07–93.33% in Seoul, Tokyo and Hong Kong, respectively, for the years 2017, 2020, 2050 and 2080. In addition, BioPCM and RUBITHERMPCM are the most efficient for improving thermal performance and saving energy in buildings in the tested regions and years.

  8. Operation of a wind turbine-flywheel energy storage system under conditions of stochastic change of wind energy.

    Science.gov (United States)

    Tomczewski, Andrzej

    2014-01-01

    The paper presents the issues of a wind turbine-flywheel energy storage system (WT-FESS) operation under real conditions. Stochastic changes of wind energy in time cause significant fluctuations of the system output power and as a result have a negative impact on the quality of the generated electrical energy. In the author's opinion it is possible to reduce the aforementioned effects by using an energy storage of an appropriate type and capacity. It was assumed that based on the technical parameters of a wind turbine-energy storage system and its geographical location one can determine the boundary capacity of the storage, which helps prevent power cuts to the grid at the assumed probability. Flywheel energy storage was selected due to its characteristics and technical parameters. The storage capacity was determined based on an empirical relationship using the results of the proposed statistical and energetic analysis of the measured wind velocity courses. A detailed algorithm of the WT-FESS with the power grid system was developed, eliminating short-term breaks in the turbine operation and periods when the wind turbine power was below the assumed level.

  9. Operation of a Wind Turbine-Flywheel Energy Storage System under Conditions of Stochastic Change of Wind Energy

    Science.gov (United States)

    2014-01-01

    The paper presents the issues of a wind turbine-flywheel energy storage system (WT-FESS) operation under real conditions. Stochastic changes of wind energy in time cause significant fluctuations of the system output power and as a result have a negative impact on the quality of the generated electrical energy. In the author's opinion it is possible to reduce the aforementioned effects by using an energy storage of an appropriate type and capacity. It was assumed that based on the technical parameters of a wind turbine-energy storage system and its geographical location one can determine the boundary capacity of the storage, which helps prevent power cuts to the grid at the assumed probability. Flywheel energy storage was selected due to its characteristics and technical parameters. The storage capacity was determined based on an empirical relationship using the results of the proposed statistical and energetic analysis of the measured wind velocity courses. A detailed algorithm of the WT-FESS with the power grid system was developed, eliminating short-term breaks in the turbine operation and periods when the wind turbine power was below the assumed level. PMID:25215326

  10. Exploring ecosystem-change and society through a landscape lens

    DEFF Research Database (Denmark)

    Plieninger, Tobias; Kizos, Thanasis; Bieling, Claudia

    2015-01-01

    for landscape research. We review and synthesize findings from six important areas of landscape research in Europe and discuss how these findings may advance the study of ecosystem change and society and its thematic key priorities. These six areas are: (1) linkages between people and the environment......Landscapes are closely linked to human well-being, but they are undergoing rapid and fundamental change. Understanding the societal transformation underlying these landscape changes, as well as the ecological and societal outcomes of landscape transformations across scales are prime areas...... in landscapes, (2) landscape structure and land-use intensity, (3) long-term landscape history, (4) driving forces, processes, and actors of landscape change, (5) landscape values and meanings, and (6) landscape stewardship. We propose that these knowledge areas can contribute to the study of ecosystem change...

  11. China's energy consumption under the global economic crisis: Decomposition and sectoral analysis

    International Nuclear Information System (INIS)

    Li, Fangyi; Song, Zhouying; Liu, Weidong

    2014-01-01

    It is now widely recognized that there is a strong relationship between energy consumption and economic growth. Most countries′ energy demands declined during the economic depression of 2008–2009 when a worldwide economic crisis occurred. As an export-oriented economy, China suffered a serious exports decline in the course of the crisis. However, it was found that energy consumption continued to increase. Against such a background, this paper aims to assess and explain the factors causing the growth of energy consumption in China. First, we will explain the impact of domestic final use and international trade on energy consumption by using decomposition analysis. Second, embodied energy and its variation across sectors are quantified to identify the key sectors contributing to the growth. Lastly, the policy implications for long-term energy conservation are discussed. The results show that the decline in exports was one of the driving forces for energy consumption reduction in the crisis, but that the growth of domestic demand in manufacturing and construction, largely stimulated by economic stimulus plans, had the opposite effect on energy consumption. International trade contributed to decreasing energy consumption of China during and after the crisis because the structure of exports and imports changed in this period. - Highlights: • We analyze the reasons for China's energy consumption change under the global economic crisis during 2007–2010. • Domestic final use growth, especially in construction and manufacturing of machinery and equipment, resulted in energy consumption increase. • International trade is identified as a driver of energy consumption reduction during and after the crisis. • Increasing China's share of consumption or reducing its share of investment in the GDP can reduce national energy intensity

  12. Sustaining ecosystem services in cultural landscapes

    Directory of Open Access Journals (Sweden)

    Tobias Plieninger

    2014-06-01

    Full Text Available Classical conservation approaches focus on the man-made degradation of ecosystems and tend to neglect the social-ecological values that human land uses have imprinted on many environments. Throughout the world, ingenious land-use practices have generated unique cultural landscapes, but these are under pressure from agricultural intensification, land abandonment, and urbanization. In recent years, the cultural landscapes concept has been broadly adopted in science, policy, and management. The interest in both outstanding and vernacular landscapes finds expression in the UNESCO World Heritage Convention, the European Landscape Convention, and the IUCN Protected Landscape Approach. These policies promote the protection, management, planning, and governance of cultural landscapes. The ecosystem services approach is a powerful framework to guide such efforts, but has rarely been applied in landscape research and management. With this paper, we introduce a special feature that aims to enhance the theoretical, empirical and practical knowledge of how to safeguard the resilience of ecosystem services in cultural landscapes. It concludes (1 that the usefulness of the ecosystem services approach to the analysis and management of cultural landscapes should be reviewed more critically; (2 that conventional ecosystem services assessment needs to be complemented by socio-cultural valuation; (3 that cultural landscapes are inherently changing, so that a dynamic view on ecosystem services and a focus on drivers of landscape change are needed; and (4 that managing landscapes for ecosystem services provision may benefit from a social-ecological resilience perspective.

  13. STRATEGIC ENERGY SECURITY OUTLOOK FORMATION OF UKRAINE UNDER EUROPEAN INTEGRATION PROCESS

    OpenAIRE

    Voynarenko, Mykhaylo Petrovych; Mykolyuk, Oksana Anatoliyivna

    2017-01-01

    Urgency of the research. Energy security affects the competitiveness of national production in the world markets and the competitiveness of the national economy under globalization. Target setting. Implementation of existing potential requires a deep reform of the regulatory and legal framework and the requirements of international agreements in full. Actual scientific researches and issues analysis. Some aspects of energy security in terms of European integration exploring Barannik V., V. Ge...

  14. Under-reporting of dietary energy intake in five populations of the African diaspora.

    Science.gov (United States)

    Orcholski, Lindsay; Luke, Amy; Plange-Rhule, Jacob; Bovet, Pascal; Forrester, Terrence E; Lambert, Estelle V; Dugas, Lara R; Kettmann, Elizabeth; Durazo-Arvizu, Ramon A; Cooper, Richard S; Schoeller, Dale A

    2015-02-14

    Studies on the role of diet in the development of chronic diseases often rely on self-report surveys of dietary intake. Unfortunately, many validity studies have demonstrated that self-reported dietary intake is subject to systematic under-reporting, although the vast majority of such studies have been conducted in industrialised countries. The aim of the present study was to investigate whether or not systematic reporting error exists among the individuals of African ancestry (n 324) in five countries distributed across the Human Development Index (HDI) scale, a UN statistic devised to rank countries on non-income factors plus economic indicators. Using two 24 h dietary recalls to assess energy intake and the doubly labelled water method to assess total energy expenditure, we calculated the difference between these two values ((self-report - expenditure/expenditure) × 100) to identify under-reporting of habitual energy intake in selected communities in Ghana, South Africa, Seychelles, Jamaica and the USA. Under-reporting of habitual energy intake was observed in all the five countries. The South African cohort exhibited the highest mean under-reporting ( - 52·1% of energy) compared with the cohorts of Ghana ( - 22·5%), Jamaica ( - 17·9%), Seychelles ( - 25·0%) and the USA ( - 18·5%). BMI was the most consistent predictor of under-reporting compared with other predictors. In conclusion, there is substantial under-reporting of dietary energy intake in populations across the whole range of the HDI, and this systematic reporting error increases according to the BMI of an individual.

  15. Secure Distributed Detection under Energy Constraint in IoT-Oriented Sensor Networks.

    Science.gov (United States)

    Zhang, Guomei; Sun, Hao

    2016-12-16

    We study the secure distributed detection problems under energy constraint for IoT-oriented sensor networks. The conventional channel-aware encryption (CAE) is an efficient physical-layer secure distributed detection scheme in light of its energy efficiency, good scalability and robustness over diverse eavesdropping scenarios. However, in the CAE scheme, it remains an open problem of how to optimize the key thresholds for the estimated channel gain, which are used to determine the sensor's reporting action. Moreover, the CAE scheme does not jointly consider the accuracy of local detection results in determining whether to stay dormant for a sensor. To solve these problems, we first analyze the error probability and derive the optimal thresholds in the CAE scheme under a specified energy constraint. These results build a convenient mathematic framework for our further innovative design. Under this framework, we propose a hybrid secure distributed detection scheme. Our proposal can satisfy the energy constraint by keeping some sensors inactive according to the local detection confidence level, which is characterized by likelihood ratio. In the meanwhile, the security is guaranteed through randomly flipping the local decisions forwarded to the fusion center based on the channel amplitude. We further optimize the key parameters of our hybrid scheme, including two local decision thresholds and one channel comparison threshold. Performance evaluation results demonstrate that our hybrid scheme outperforms the CAE under stringent energy constraints, especially in the high signal-to-noise ratio scenario, while the security is still assured.

  16. Landscape planning as a contribution to the assessment and finding of sites for energy facilities from an ecological and creative point of view

    International Nuclear Information System (INIS)

    Buchwald, K.

    1977-01-01

    The environmental agreeability examination through landscape planning in connection with the finding of sites for power stations and their integration into area planning is explained. The procedure of landscape planning for the assessment of power station sites is also presented. (RW) [de

  17. A Three-Box Model of Thermohaline Circulation under the Energy Constraint

    International Nuclear Information System (INIS)

    Shen Yang; Guan Yu-Ping; Liang Chu-Jin; Chen Da-Ke

    2011-01-01

    The driving mechanism of thermohaline circulation is still a controversial topic in physical oceanography. Classic theory is based on Stommel's two-box model under buoyancy constraint. Recently, Guan and Huang proposed a new viewpoint in the framework of energy constraint with a two-box model. We extend it to a three-box model, including the effect of wind-driven circulation. Using this simple model, we further study how ocean mixing impacts on thermohaline circulation under the energy constraint. (geophysics, astronomy, and astrophysics)

  18. Renewable energy investments under different support schemes: A real options approach

    DEFF Research Database (Denmark)

    Boomsma, Trine Krogh; Meade, Nigel; Fleten, Stein-Erik

    2012-01-01

    -in tariff encourages earlier investment. Nevertheless, as investment has been undertaken, renewable energy certificate trading creates incentives for larger projects. In our baseline scenario and taking the fixed feed-in tariff as a base, the revenue required to trigger investments is 61% higher......This paper adopts a real options approach to analyze investment timing and capacity choice for renewable energy projects under different support schemes. The main purpose is to examine investment behavior under the most extensively employed support schemes, namely, feed-in tariffs and renewable...... with renewable certificates. At the same time, investment capacity is 61% higher....

  19. Licensing procedures under the Atomic Energy Act in comparison to those under the Federal Pollution Control Act. [Federal Republic of Germany

    Energy Technology Data Exchange (ETDEWEB)

    Herkommer, E.; Wolleschlaeger, M.

    1981-07-01

    Since there is the possibility in uranium enrichment plants of major quantities of gaseous fluorine compounds being released, it is necessary in the Federal Republic of Germany to consider for such plants not only a permit under the Atomic Energy Act, but also a permit under the Federal Pollution Control Act. Under Sec. 8, Subsec. 2, such permit is included in the permit under the Atomic Energy Act, but the licensing authority under the Atomic Energy Act must take its decision in agreement with the state authority responsible for pollution control.

  20. Micro-size cogeneration plants and virtual power plants. New energy landscapes; Mikro-KWK und virtuelle Kraftwerke. Neue Energielandschaften

    Energy Technology Data Exchange (ETDEWEB)

    Roon, Serafin von [Forschungsstelle fuer Energiewirtschaft e.V., Muenchen (Germany)

    2009-07-01

    Combined heat and power generation is an established technology. With micro-size cogeneration units, the technology is now available to private single or multiple dwellings and for decentral power supply of residential blocks. With the right political boundary conditions and integrated into virtual power stations, this is an option for enhanced use of renewable energy sources and for decentral, flexible and climate-friendly heat and power generation in buildings. Economic efficiency analyses by experts, high utilisation rates, innovative developments of the manufacturers and a positive public image are all in favour of a great future for micro-size cogeneration units. (orig.)

  1. Expectations for renewable energy under market restructuring: the U.S. experience

    International Nuclear Information System (INIS)

    Heiman, M.K.

    2006-01-01

    The 1992 Energy Policy Act encouraged states to open up electricity provision to market competition. Many analysts predicted that renewable energy would take off in the deregulated market where consumers could choose their power provider and utilities would no longer be enticed to build large central power plants under guaranteed rates of return. This article outlines the flaws with that expectation. Absent a strong federal commitment, the states continue to lead with support for renewable energy. However the base from which to expand is so low, and the level of support so tenuous, that renewable energy will continue to play only a minor role in meeting U.S. energy demands with current policy in place. Furthermore, the evidence does not support the expectation that market restructuring, in and of itself, leads to a stronger state commitment to renewable energy. The failure of renewable energy to become a major component of the U.S. energy mix is not due to any intrinsic problem with the technology employed, nor with the cost of generation. Rather weak penetration may be attributed to broader forces exacerbated by market restructuring and overcome only through strong and reliable federal intervention in support of renewable energy. (author)

  2. Thermal dynamic simulation of wall for building energy efficiency under varied climate environment

    Science.gov (United States)

    Wang, Xuejin; Zhang, Yujin; Hong, Jing

    2017-08-01

    Aiming at different kind of walls in five cities of different zoning for thermal design, using thermal instantaneous response factors method, the author develops software to calculation air conditioning cooling load temperature, thermal response factors, and periodic response factors. On the basis of the data, the author gives the net work analysis about the influence of dynamic thermal of wall on air-conditioning load and thermal environment in building of different zoning for thermal design regional, and put forward the strategy how to design thermal insulation and heat preservation wall base on dynamic thermal characteristic of wall under different zoning for thermal design regional. And then provide the theory basis and the technical references for the further study on the heat preservation with the insulation are in the service of energy saving wall design. All-year thermal dynamic load simulating and energy consumption analysis for new energy-saving building is very important in building environment. This software will provide the referable scientific foundation for all-year new thermal dynamic load simulation, energy consumption analysis, building environment systems control, carrying through farther research on thermal particularity and general particularity evaluation for new energy -saving walls building. Based on which, we will not only expediently design system of building energy, but also analyze building energy consumption and carry through scientific energy management. The study will provide the referable scientific foundation for carrying through farther research on thermal particularity and general particularity evaluation for new energy saving walls building.

  3. Towards nearly zero-energy buildings. Definition of common principles under the EPBD. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hermelink, A.; Schimschar, S.; Boermans, T. [Ecofys, Utrecht (Netherlands); Pagliano, L.; Zangheri, P.; Armani, R. [Energy Department, Politecnico di Milano, Milan (Italy); Voss, K.; Musall, E. [University of Wuppertal, Wuppertal (Germany)

    2013-02-15

    Europe aims at bringing about drastic reductions of greenhouse gas emissions in the residential and service sectors of about 90% compared to 1990 by 2050. Nearly Zero-Energy Buildings are a major element of European climate policy. Already by 2021, every new building in Europe has to meet this standard. During 2012, a consortium led by Ecofys undertook a study for the European Commission to provide more guidance to Member States and the Commission with regards to the implementation of the requirements for nearly zero-energy buildings under the EPBD. The study features benchmarks for nearly zero-energy buildings for different European climates, an analytical framework for evaluating Member States national plans for increasing the number of nearly zero energy buildings, a reporting template for these plans and an analysis of the convergence between cost optimal levels and nearly zero-energy buildings.

  4. [Review on landscape heterogeneity].

    Science.gov (United States)

    Zhao, Yutao; Yu, Xinxiao; Guang, Wenbin

    2002-04-01

    On the base of precedent studies, the occurring mechanism, classification, measurement methods, and the important role of landscape heterogeneity in landscape ecology were reviewed. The inner and outer uncertain factors result in landscape heterogeneity. Landscape heterogeneity has close relations with landscape stability, landscape design, architecture, management and disturbance, scale and ecological diversity in ecology. Complexity of landscape heterogeneity research, non-system of measurement indices and methods, difficulties and limitations of landscape heterogeneity modelling were all discussed respectively. In addition, it is suggested that the theory and methods of ecological complexity should be used to improve landscape heterogeneity research.

  5. Modelling of domestic refrigerators' energy consumption under real life conditions in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Geppert, Jasmin

    2011-05-23

    In recent decades, energy and resource savings have become increasingly important, not only in the industrial, but also the residential sector. As one of the largest energy users in private homes, domestic refrigerators and freezers were among the first appliances to be targeted for energy efficiency improvements. With the aim of encouraging manufacturers to develop and produce more efficient appliances, the European Energy Label was introduced in the mid-nineties. However, the energy use of refrigerators does not only depend on technical components and features. Especially the using conditions in private homes are of a decisive influence. Thus, the present study has been conducted to test the sensitivity of refrigerators' energy consumption to various usage conditions within realistic ranges, which have been determined by means of two empirical studies. Key information gathered from the experiments were used as a base for the development and validation of a simplified model that allows predicting the energy consumption of refrigerators in use. The practical experiments were performed under controlled laboratory conditions with four different refrigerators with an A{sup +} or A{sup ++} energy efficiency rating (two statically cooled built-in fridge-freezers, one dynamically cooled refrigerator and one statically cooled refrigerator). The investigations revealed that the ambient temperature has the greatest impact on a refrigerator's energy consumption, followed by thermostat setting and heat load by insertion of warm items. The refrigerators' load under static conditions as well as the number of door openings have almost no impact on energy consumption. The modelling methodology follows a first-principle approach adjusted by experimental data. When compared to experimental results, model predictions show a reasonable agreement for the whole range of investigated conditions. (orig.)

  6. Changing wind-power landscapes

    DEFF Research Database (Denmark)

    Möller, Bernd

    2006-01-01

    After more than 25 years of continuous development, Danish wind-energy landscapes are due for face changes. On-shore construction has ceased and necessary re-powering schemes have not been introduced as yet. Regional planning is discouraging, while conditions for erecting new turbines have become...... more stringent. One of the factors inhibiting development seems to be uncertainty in planning about the future impact on landscapes. Visual impact has rarely been an issue so far, but ever-increasing turbine size and less local involvement may change this. This paper presents a deterministic approach...... of determining the likely visual-impact on landscapes and population, taking into account that there is no clear threshold for perceived adverse visual-impact. A geographical information system (GIS) has been used to build a regional landscape model for Northern Jutland County, which is used to assess visibility...

  7. Cuban Landscapes

    DEFF Research Database (Denmark)

    Scarpaci, Joseph L.; Portela, Armando

    This accessible book offers a vivid geographic portrait of Cuba, exploring the island’s streetscapes, sugar cane fields, beaches, and rural settlements; its billboards, government buildings, and national landmarks. The authors illuminate how natural and built landscapes have shaped Cuban identity...... (cubanidad), and vice versa. They provide a unique perspective on Cuba’s distinct historical periods and political economies, from the colonial period through republicanism and today’s socialist era. Compelling topics include the legacies of slavery and the sugar industry, the past and future of urban...

  8. Changing Landscape

    DEFF Research Database (Denmark)

    Tunby Gulbrandsen, Ib; Kamstrup, Andreas; Koed Madsen, Anders

    to production, cooperation and communication. Following, we have witnessed a growing number of calls for attention to the effects of new ICT’s on the concept of strategic management and strategizing. Despite the numerous calls, few have answered. In this article we aim at providing a possible response beginning...... with an analysis of the changing organizational landscape created by new ICT’s like Google, Facebook, Wikipedia, iPods, smart phones and Wi-Fi. Based on five netno- and ethno-graphic investigations of the intertwinement of ICT’s and organizational work, we point to three features that have changed the scene: new...

  9. Stochastic Ratcheting on a Funneled Energy Landscape Is Necessary for Highly Efficient Contractility of Actomyosin Force Dipoles

    Science.gov (United States)

    Komianos, James E.; Papoian, Garegin A.

    2018-04-01

    Current understanding of how contractility emerges in disordered actomyosin networks of nonmuscle cells is still largely based on the intuition derived from earlier works on muscle contractility. In addition, in disordered networks, passive cross-linkers have been hypothesized to percolate force chains in the network, hence, establishing large-scale connectivity between local contractile clusters. This view, however, largely overlooks the free energy of cross-linker binding at the microscale, which, even in the absence of active fluctuations, provides a thermodynamic drive towards highly overlapping filamentous states. In this work, we use stochastic simulations and mean-field theory to shed light on the dynamics of a single actomyosin force dipole—a pair of antiparallel actin filaments interacting with active myosin II motors and passive cross-linkers. We first show that while passive cross-linking without motor activity can produce significant contraction between a pair of actin filaments, driven by thermodynamic favorability of cross-linker binding, a sharp onset of kinetic arrest exists at large cross-link binding energies, greatly diminishing the effectiveness of this contractility mechanism. Then, when considering an active force dipole containing nonmuscle myosin II, we find that cross-linkers can also serve as a structural ratchet when the motor dissociates stochastically from the actin filaments, resulting in significant force amplification when both molecules are present. Our results provide predictions of how actomyosin force dipoles behave at the molecular level with respect to filament boundary conditions, passive cross-linking, and motor activity, which can explicitly be tested using an optical trapping experiment.

  10. Stochastic Ratcheting on a Funneled Energy Landscape Is Necessary for Highly Efficient Contractility of Actomyosin Force Dipoles

    Directory of Open Access Journals (Sweden)

    James E. Komianos

    2018-04-01

    Full Text Available Current understanding of how contractility emerges in disordered actomyosin networks of nonmuscle cells is still largely based on the intuition derived from earlier works on muscle contractility. In addition, in disordered networks, passive cross-linkers have been hypothesized to percolate force chains in the network, hence, establishing large-scale connectivity between local contractile clusters. This view, however, largely overlooks the free energy of cross-linker binding at the microscale, which, even in the absence of active fluctuations, provides a thermodynamic drive towards highly overlapping filamentous states. In this work, we use stochastic simulations and mean-field theory to shed light on the dynamics of a single actomyosin force dipole—a pair of antiparallel actin filaments interacting with active myosin II motors and passive cross-linkers. We first show that while passive cross-linking without motor activity can produce significant contraction between a pair of actin filaments, driven by thermodynamic favorability of cross-linker binding, a sharp onset of kinetic arrest exists at large cross-link binding energies, greatly diminishing the effectiveness of this contractility mechanism. Then, when considering an active force dipole containing nonmuscle myosin II, we find that cross-linkers can also serve as a structural ratchet when the motor dissociates stochastically from the actin filaments, resulting in significant force amplification when both molecules are present. Our results provide predictions of how actomyosin force dipoles behave at the molecular level with respect to filament boundary conditions, passive cross-linking, and motor activity, which can explicitly be tested using an optical trapping experiment.

  11. Assessing Energy Flow in Rainfed and Irrigated Wheat Fields of Shahrekourd Township under two Tillage Systems

    Directory of Open Access Journals (Sweden)

    hossein kazemi

    2016-11-01

    Full Text Available Introduction Energy analysis of agricultural ecosystem is essential for sustainable production. The relation between agriculture and energy is very close. Agriculture is an energy consumer and the energy supplier. Agriculture’s use of energy is recognized in three external inputs: labor, machines, and fertilizers (Connor et al., 2011. Significant gains in energy efficiency were arisen in agriculture following the phenomenal increase in energy prices in the 1970s. Greater use of diesel motors, larger tractors, using conservation tillage methods and optimized fertilizer use efficiency were the main causes (Ozkan et al., 2004. Safa & Samarasinghe (2013 were reported that fuel consumption in tillage and harvesting was more than other operations in wheat fields of Canterbury, New Zealand. Effective application of agricultural techniques and efficient use of support inputs can minimize environmental problems and in consequence promote sustainable agricultural intensification. In this study, the energy flow investigated in irrigated and rain-fed wheat cropping systems under two tillage and no-tillage methods in the Shahrekourd city, during 2013. Materials and methods The study was carried out in the Sharekourd city (Chaharmahal Bakhteyari province. This region is located within 32º 20' and 32º 21' Lat. N, 50º 48' and 50º 50' Lon. E. Data were collected from 40 farmers with questionnaire method. In this study, a randomized complete design with four scenarios (rain-fed and irrigated farming with tillage and no-tillage systems was used, that 10 farms were considered as a replication in each scenario. All data detail information on the questionnaire were averaged and arranged. First, all inputs and outputs of wheat production were determined, quantified and entered into Microsoft Excel spreadsheets, and then transformed into energy units and expressed in MJ.ha-1. Based on the total energy equivalents of the inputs and output and the energy use

  12. Projecting Wind Energy Potential Under Climate Change with Ensemble of Climate Model Simulations

    Science.gov (United States)

    Jain, A.; Shashikanth, K.; Ghosh, S.; Mukherjee, P. P.

    2013-12-01

    reanalysis/ observed output. We apply the same for future under RCP scenarios. We observe spatially and temporally varying global change of wind energy density. The underlying assumption is that the regression relationship will also hold good for future. The results highlight the needs to change the design standards of wind mills at different locations, considering climate change and at the same time the requirement of height modifications for existing mills to produce same energy in future.

  13. Fatigue Crack Propagation Under Variable Amplitude Loading Analyses Based on Plastic Energy Approach

    Directory of Open Access Journals (Sweden)

    Sofiane Maachou

    2014-04-01

    Full Text Available Plasticity effects at the crack tip had been recognized as “motor” of crack propagation, the growth of cracks is related to the existence of a crack tip plastic zone, whose formation and intensification is accompanied by energy dissipation. In the actual state of knowledge fatigue crack propagation is modeled using crack closure concept. The fatigue crack growth behavior under constant amplitude and variable amplitude loading of the aluminum alloy 2024 T351 are analyzed using in terms energy parameters. In the case of VAL (variable amplitude loading tests, the evolution of the hysteretic energy dissipated per block is shown similar with that observed under constant amplitude loading. A linear relationship between the crack growth rate and the hysteretic energy dissipated per block is obtained at high growth rates. For lower growth rates values, the relationship between crack growth rate and hysteretic energy dissipated per block can represented by a power law. In this paper, an analysis of fatigue crack propagation under variable amplitude loading based on energetic approach is proposed.

  14. Energy saving in WWTP: Daily benchmarking under uncertainty and data availability limitations.

    Science.gov (United States)

    Torregrossa, D; Schutz, G; Cornelissen, A; Hernández-Sancho, F; Hansen, J

    2016-07-01

    Efficient management of Waste Water Treatment Plants (WWTPs) can produce significant environmental and economic benefits. Energy benchmarking can be used to compare WWTPs, identify targets and use these to improve their performance. Different authors have performed benchmark analysis on monthly or yearly basis but their approaches suffer from a time lag between an event, its detection, interpretation and potential actions. The availability of on-line measurement data on many WWTPs should theoretically enable the decrease of the management response time by daily benchmarking. Unfortunately this approach is often impossible because of limited data availability. This paper proposes a methodology to perform a daily benchmark analysis under database limitations. The methodology has been applied to the Energy Online System (EOS) developed in the framework of the project "INNERS" (INNovative Energy Recovery Strategies in the urban water cycle). EOS calculates a set of Key Performance Indicators (KPIs) for the evaluation of energy and process performances. In EOS, the energy KPIs take in consideration the pollutant load in order to enable the comparison between different plants. For example, EOS does not analyse the energy consumption but the energy consumption on pollutant load. This approach enables the comparison of performances for plants with different loads or for a single plant under different load conditions. The energy consumption is measured by on-line sensors, while the pollutant load is measured in the laboratory approximately every 14 days. Consequently, the unavailability of the water quality parameters is the limiting factor in calculating energy KPIs. In this paper, in order to overcome this limitation, the authors have developed a methodology to estimate the required parameters and manage the uncertainty in the estimation. By coupling the parameter estimation with an interval based benchmark approach, the authors propose an effective, fast and reproducible

  15. A material optimization model to approximate energy bounds for cellular materials under multiload conditions

    DEFF Research Database (Denmark)

    Guedes, J.M.; Rodrigues, H.C.; Bendsøe, Martin P.

    2003-01-01

    This paper describes a computational model, based on inverse homogenization and topology design, for approximating energy bounds for two-phase composites under multiple load cases. The approach allows for the identification of possible single-scale cellular materials that give rise to the optimal...

  16. Effect of methanol on the liquefaction reaction of biomass in hot compressed water under microwave energy

    Science.gov (United States)

    Junming Xu; Jianchun Jiang; Chun-Yun Hse; Todd F. Shupe

    2013-01-01

    Liquefaction of sawdust was studied in methanol-water solutions using an acid catalyst under microwave energy. The effect of the methanol concentration on the changes of components in the liquefied products was analyzed by gas chromatography−mass spectrometry (GC−MS). It was found that 5-hydroxymethylfurfural (HMF) and levulinic acid are the...

  17. 76 FR 15268 - Guidelines for Determining Probability of Causation Under the Energy Employees Occupational...

    Science.gov (United States)

    2011-03-21

    ... relative risk (ERR) values and using the 99th percentile of that probability distribution in the... Guidelines for Determining Probability of Causation Under the Energy Employees Occupational Illness... on the rulemaking process, see the ``Public Participation'' heading of the SUPPLEMENTARY INFORMATION...

  18. Characterization of adult ghrelin and ghrelin receptor knockout mice under positive and negative energy balance

    Science.gov (United States)

    Ghrelin and the ghrelin receptor (GH secretagogue receptor, GHS-R) are believed to have important roles in energy homeostasis. We describe results from the first studies to be conducted in congenic (N10) adult ghrelin(-/-) and Ghsr(-/-) mice under conditions of both positive (high-fat diet) and nega...

  19. Anomalous energy cascades in dense granular materials yielding under simple shear deformations

    NARCIS (Netherlands)

    Saitoh, K.; Mizuno, Hideyuki

    2015-01-01

    By using molecular dynamics (MD) simulations of dense granular particles in two dimensions, we study turbulent-like structures of their non-affine velocities under simple shear deformations. We find that the spectrum of non-affine velocities, introduced as an analog of energy spectrum for turbulent

  20. Study of beryllium redeposition under bombardment by high intensity -low energy- hydrogen ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Gureev, V.M.; Guseva, M.I.; Danelyan, L.S. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)] [and others

    1998-01-01

    The results of studying the erosion of beryllium under an effect of intense ion fluxes with the energy of 250 eV, at the fluences {approx}10{sup 2}1 cm{sup -2}, at the MAGRAS-stand are given. The operating conditions under which a practically-complete redeposition of the sputtered beryllium upon the target surface were experimentally-realized. A change in the microstructure of a beryllium target under sputtering and redeposition is analyzed. Some technological applications are considered. (author)

  1. Bi-Objective Flexible Job-Shop Scheduling Problem Considering Energy Consumption under Stochastic Processing Times.

    Science.gov (United States)

    Yang, Xin; Zeng, Zhenxiang; Wang, Ruidong; Sun, Xueshan

    2016-01-01

    This paper presents a novel method on the optimization of bi-objective Flexible Job-shop Scheduling Problem (FJSP) under stochastic processing times. The robust counterpart model and the Non-dominated Sorting Genetic Algorithm II (NSGA-II) are used to solve the bi-objective FJSP with consideration of the completion time and the total energy consumption under stochastic processing times. The case study on GM Corporation verifies that the NSGA-II used in this paper is effective and has advantages to solve the proposed model comparing with HPSO and PSO+SA. The idea and method of the paper can be generalized widely in the manufacturing industry, because it can reduce the energy consumption of the energy-intensive manufacturing enterprise with less investment when the new approach is applied in existing systems.

  2. Analysis of under-frequency load shedding considering renewable energy for isolated systems

    Directory of Open Access Journals (Sweden)

    Hong-Chan Chang

    2016-01-01

    Full Text Available This article focuses on the effect of under-frequency load shedding with renewable energy for isolated systems. Therefore, this article will apply PSS/E software to simulate the operating characteristics of an off-island system connected to battery energy storage in parallel in order to determine energy storage capacity. Wind energy operation and case analysis are used to integrate the systems that can improve under-frequency influence, in order to determine appropriate storage and AC–DC inverter capacities. First, the wind power generation data of isolated systems of 2011, 2012, and 2013 are used to estimate the storage and inverter capacities for 1, 2, 6, 12, and 24 h daily. With the above data of about 900 days, Gaussian distribution is applied to analyze the frequencies, sizes, accumulated probabilities, and other factors. Second, the annual electricity sales of isolated systems are used to determine more economic capacities for the battery storage energy and inverter. Finally, the economic analysis of the four cases is conducted, according to PSS/E software analysis, in order to determine the optimal capacity for battery energy storage devices and inverter.

  3. Fine powder flow under humid environmental conditions from the perspective of surface energy.

    Science.gov (United States)

    Karde, Vikram; Ghoroi, Chinmay

    2015-05-15

    The influence of humidity on surface energetics and flow behavior of fine pharmaceutical powders was investigated. Amorphous and crystalline fine powders with hydrophilic (Corn starch and Avicel PH105) and hydrophobic (ibuprofen) nature were considered for this study. The surface energy was determined using surface energy analyzer and flow behavior was measured in terms of unconfined yield stress (UYS) using a shear tester. The study showed that unlike hydrophobic ibuprofen powder, surface energy and flow of hydrophilic excipient powders were affected by relative humidity (RH). The Lifshitz-van der Waals dispersive (γ(LW)) component of surface energy barely changed with varying RH for all pharmaceutical powders. For hydrophilic excipients, the specific component of surface energy (γ(SP)) was found to increase with increasing RH. Furthermore, for these excipients, flow deterioration at elevated RH was observed due to increased capillary bridge formation. Detailed analysis showed that γ(SP) component of surface energy can be an effective indicator for flow behavior of fine powders under varying humid conditions. The present study also brought out the existence of different regimes of probable interparticle forces which dictate the bulk flow behavior of fine hydrophilic powder under humid conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Solar energy efficiency of cocoa clones cultivated under three species of shade trees.

    Directory of Open Access Journals (Sweden)

    Oscar Regazzoni

    2015-04-01

    Full Text Available This experiment aims to know the solar energy efficiency of four clones of cocoa that cultivated under three different shading plants. This experiment has been done from September until December 2013 located at Kaliwining Experiment Farm with characteristic 45 m above sea level, soil type is low humic gley, soil texture is silty clay loam, and climate classification type D based on Scmidht and Fergusson Classification. This experiment used Nested Design as Experimental Design with species of shading plant as main plot which are Teak (Tectona grandis L., Krete (Cassia surattensis (Burm. F., Lamtoro (Leucaena leucocephala L. and Cocoa clones as sub plot which are Sulawesi 1, Sulawesi 2, KKM 22, KW 165. The observation of solar energy efficiency consists of daily solar radiation intensity, solar radiation intensity above plant, solar radiation intensity under plant, and also plant total dry weight. The experimental result showed that there is differences (heterogenity between shading location based on homogenity test by Bartlett Method. There are some interaction between the kind of shading plant and clones in parameter of interception efficiency, absorbtion efficiency, the efficiency of solar energy that caught by plant, and solar energy conversion efficiency. The efficiency of solar energy that caught by plant will affect the solar energy conversion efficiency with R2 = 0,86.

  5. Transition in the decay rates of stationary distributions of Lévy motion in an energy landscape

    Science.gov (United States)

    Kaleta, Kamil; Lőrinczi, József

    2016-02-01

    The time evolution of random variables with Lévy statistics has the ability to develop jumps, displaying very different behaviors from continuously fluctuating cases. Such patterns appear in an ever broadening range of examples including random lasers, non-Gaussian kinetics, or foraging strategies. The penalizing or reinforcing effect of the environment, however, has been little explored so far. We report a new phenomenon which manifests as a qualitative transition in the spatial decay behavior of the stationary measure of a jump process under an external potential, occurring on a combined change in the characteristics of the process and the lowest eigenvalue resulting from the effect of the potential. This also provides insight into the fundamental question of what is the mechanism of the spatial decay of a ground state.

  6. PESP Landscaping Initiative

    Science.gov (United States)

    Landscaping practices can positively or negatively affect local environments and human health. The Landscaping Initiative seeks to enhance benefits of landscaping while reducing need for pesticides, fertilizers, etc., by working with partners.

  7. Solar energy contribution to the energy demand for air conditioning system in an office building under Tripoli climate conditions

    Directory of Open Access Journals (Sweden)

    Musbah Mohamed H.

    2014-01-01

    Full Text Available The feasibility of solar assisted air conditioning in an office building under Tripoli weather conditions is investigated in this paper. A single-effect lithium bromide absorption cycle powered by means of flat-plate solar collectors was modeled in order to predict the potential of the solar energy share. The cooling load profile was generated by using an detailed hourly based program and Typical meteorological year for Tripoli. System performance and solar energy fraction were calculated by varying two major parameters (collector’s slope angle and collector area. The maximum solar fraction of 48% was obtained by means of 1400 m2 of collector surface area. Analysis of results showed that, besides the collector surface area, the main factors affecting the solar fraction were the local weather conditions (intensity of incident solar radiation and the time of day when the plant was operated.

  8. Landscape & Imagination: riflettere insieme

    Directory of Open Access Journals (Sweden)

    Mariella Zoppi

    2015-10-01

    Full Text Available In Paris, at La Villette University, was four-days of debate on 2-4 Mai 2013, in which faculty members of all the world discussed on methods and experiences in teaching landscape. The conference was organized in multiple sessions: history, theories, representation, process, science and governance. All the fields discussed were related to the main problem of the identity of territories in the landscape project -from the theories to the practices- and applied in a very large range of different situations: from the rural world between conservation and transformations to the coastal areas under the pressure of tourism, from the ecology in the city life renovation to the land use control and project by community and the emergency management in natural catastrophes.

  9. Real-time powder diffraction studies of energy materials under non-equilibrium conditions

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Vanessa K.; Auckett, Josie E.; Pang, Wei-Kong

    2017-09-01

    Energy materials form the central part of energy devices. An essential part of their function is the ability to reversibly host charge or energy carriers, and analysis of their phase composition and structure in real time under non-equilibrium conditions is mandatory for a full understanding of their atomic-scale functional mechanism. Real-time powder diffraction is increasingly being applied for this purpose, forming a critical step in the strategic chemical engineering of materials with improved behaviour. This topical review gives examples of real-time analysis using powder diffraction of rechargeable battery electrodes and porous sorbent materials used for the separation and storage of energy-relevant gases to demonstrate advances in the insights which can be gained into their atomic-scale function.

  10. Contemporary danish landscape research

    DEFF Research Database (Denmark)

    Vejre, H.; Brandt, J.

    2004-01-01

    Danish landscape research blossomed during the 1990’ies thanks to several transdisciplinary research programmes involving several institutions. The main themes of the programmes encompassed Landscape change, landscape and biological diversity, nature and landscape management, use and monitoring o...... of the countryside. The values of the Danish landscape pertain mainly to the coastal landscapes. The threats include the industrilization of the agricultural landsclaes and,in places urban sprawl....

  11. Assessing landscape hydroperiods across the Mekong Basin using multi-scale remote sensing to understand water-energy-food tradeoffs

    Science.gov (United States)

    Torbick, N.; Salas, W.; Qi, J.; Huang, X.

    2017-12-01

    In the Lower Mekong River Basin (LMRB), population growth and transitioning economies, shifting climate, and intense pressures for resources are driving tradeoffs among the water-enegery-food (WEF) nexus. Rice production and irrigation, wetlands habitat, and damn constructions are intertwinned across the region. There are 11 major hydropower dams on the main stem of the Lower Mekong River and many smaller dams in the basin. At the same time increased pressure for food production has amplified cropping intensity and irrigation infrastructure projects. These human acitivies are impacting inundation patterns and phenology of wetland and lake ecosystems. We are mapping rice, wetlands, and lake inundation dynamics using multi-scale satellite remote sensing. New opportunities exist for moderate scale, near-daily mapping of rice, wetland, shrimp, and lake hydroperiod with multi-source imaging and BigData computational approaches on the NAS cloud. Primarily we rely on Sentinel-1 IW and PALSAR-2 ScanSAR to map inundation dynamics at 10m resolution including under canopy conditions using double bounce properties. As part of this effort we are assessing different damn impacts at case studies in Thailand, Cambodia, Laos, and Vietnam with high resolution commercial imagery, social surveys, and socioeconomic models. These dams are currently regulated individually without coordination. As a result, their operation has outsized impacts on lake and wetland ecologies, negatively affecting the associated ecosystem services that local communities have relied on. All new products are shared openly with the science community. Case study illustrations will be presented.

  12. Stochastic–multiobjective market equilibrium analysis of a demand response program in energy market under uncertainty

    International Nuclear Information System (INIS)

    Hu, Ming-Che; Lu, Su-Ying; Chen, Yen-Haw

    2016-01-01

    Highlights: • Analyze the impact of a demand response program under uncertainty. • Stochastic Nash–Cournot competition model is formulated. • Case study of the Taiwanese electric power market is conducted. • Demand response decreases power price, generation, and emissions. • Demand uncertainty increases energy price and supply risk in the results. - Abstract: In the electricity market, demand response programs are designed to shift peak demand and enhance system reliability. A demand response program can reduce peak energy demand, power transmission congestion, or high energy-price conditions by changing consumption patterns. The purpose of this research is to analyze the impact of a demand response program in the energy market, under demand uncertainty. A stochastic–multiobjective Nash–Cournot competition model is formulated to simulate demand response in an uncertain energy market. Then, Karush–Kuhn–Tucker optimality conditions and a linear complementarity problem are derived for the stochastic Nash–Cournot model. Accordingly, the linear complementarity problem is solved and its stochastic market equilibrium solution is determined by using a general algebraic modeling system. Additionally, the case of the Taiwanese electric power market is taken up here, and the results show that a demand response program is capable of reducing peak energy consumption, energy price, and carbon dioxide emissions. The results show that demand response program decreases electricity price by 2–10%, total electricity generation by 0.5–2%, and carbon dioxide emissions by 0.5–2.5% in the Taiwanese power market. In the simulation, demand uncertainty leads to an 2–7% increase in energy price and supply risk in the market. Additionally, tradeoffs between cost and carbon dioxide emissions are presented.

  13. Benefits from increased cooperation and energy trade under CO2 commitments - the Nordic case

    International Nuclear Information System (INIS)

    Unger, T.; Ekvall, T.

    2003-01-01

    In this paper, benefits from increasing cross-border cooperation under future CO 2 commitments in the Nordic countries are examined and evaluated. Four cooperative strategies are analyzed and valued separately: cross-border electricity trade, cross-border emission-permit trade, the introduction of a trans-Nordic natural gas transmission grid, and, finally, utilization of all these three strategies simultaneously. The valuation is done under varying CO 2 commitments and under three different scenarios for future energy demand and technological development. In conducting this analysis, the energy-systems model-generator MARKAL (MARKet ALlocation) was used to model the Nordic energy system. It is shown that all cooperative strategies do lower the abatement costs considerably, especially if the strategy including full cooperation is utilized. In this case, additional costs from meeting CO 2 targets may be at least halved for commitments less than 10% reduction until 2050 based on emissions in 1995. No significant difference between low and high CO 2 commitments could be observed in the size of the benefits from cooperation, expressed in billions (10 9 ) of Swedish crowns. Benefits from cooperation are generally larger for scenarios including relatively higher future energy demand. (author)

  14. Regional energy resource development and energy security under CO2 emission constraint in the greater Mekong sub-region countries (GMS)

    International Nuclear Information System (INIS)

    Watcharejyothin, Mayurachat; Shrestha, Ram M.

    2009-01-01

    The paper evaluates effects of energy resource development within the Greater Mekong Sub-region (GMS) on energy supply mix, energy system cost, energy security and environment during 2000-2035. A MARKAL-based integrated energy system model of the five GMS countries was developed to examine benefits of regional energy resource development for meeting the energy demand of these countries. The study found that an unrestricted energy resource development and trade within the region would reduce the total-regional energy systems cost by 18% and would abate the total CO 2 emission by 5% as compared to the base case. All the five countries except Myanmar would benefit from the expansion of regional energy resource integration in terms of lower energy systems costs and better environmental qualities. An imposition of CO 2 emission reduction constraint by 5% on each of the study countries from that of the corresponding emissions under the unrestricted energy resource development in the GMS is found to improve energy security, reduce energy import and fossil fuels dependences and increase volume of power trade within the region. The total energy system cost under the joint CO 2 emission reduction strategy would be less costly than that under the individual emission targets set for each country.

  15. Effect of energy under-reporting on secular trends of dietary patterns in a mediterranean population.

    Directory of Open Access Journals (Sweden)

    Anna N Funtikova

    Full Text Available Diet is an important factor in the prevention of chronic diseases. Analysis of secular trends of dietary patterns can be biased by energy under-reporting. Therefore, the objective of the present study was to analyse the impact of energy under-reporting on dietary patterns and secular trends in dietary patterns defined by cluster analysis.Two cross-sectional population-based surveys were conducted in Spain, in 2000 and 2005, with 3058 and 6352 participants, respectively, aged 25 to 74 years. Validated questionnaire was used to collect dietary data. Cluster analysis was run separately for all participants, plausible energy reporters (PER, and energy under-reporters (EUR to define dietary patterns.Three clusters, "healthy", "mixed" and "western", were identified for both surveys. The "mixed" cluster was the predominant cluster in both surveys. Excluding EUR reduced the proportion of the "mixed" cluster up to 6.40% in the 2000 survey; this caused secular trend increase in the prevalence of the "mixed" pattern. Cross-classification analysis of all participants and PER' data showed substantial agreement in cluster assignments: 68.7% in 2000 and 84.4% in 2005. Excluding EUR did not cause meaningful (≥ 15% changes in the "healthy" pattern. It provoked changes in consumption of some food groups in the "mixed" and "western" patterns: mainly decreases of unhealthy foods within the 2000 and increases of unhealthy foods within the 2005 surveys. Secular trend effects of EUR were similar to those within the 2005 survey. Excluding EUR reversed the direction of secular trends in consumption of several food groups in PER in the "mixed" and "western" patterns.EUR affected distribution of participants between dietary patterns within and between surveys, secular trends in food group consumption and amount of food consumed in all, but not in the "healthy" pattern. Our findings emphasize threats from energy under-reporting in dietary data analysis.

  16. Driving under the influence behaviours among high school students who mix alcohol with energy drinks.

    Science.gov (United States)

    Wilson, Maria N; Cumming, Tammy; Burkhalter, Robin; Langille, Donald B; Ogilvie, Rachel; Asbridge, Mark

    2017-11-29

    Alcohol and energy drinks are commonly used substances by youth in Canada, and are often mixed (AmED). While several studies have shown that AmED can have dangerous effects, less well understood is how AmED is associated with driving under the influence of either alcohol or drugs. This study sought to determine whether youth who use AmED were more likely to engage in driving, or being a passenger of a driver, under the influence of alcohol or cannabis compared to youth who use either alcohol or energy drinks alone. This study used data from grade 10-12 students who took part in the 2014/2015 Canadian Student Tobacco, Alcohol and Drugs Survey (N=17,450). The association of past-year AmED use with past-30day: driving under the influence of alcohol or cannabis, and riding with an alcohol- or cannabis-influenced driver, was assessed using logistic regression. One in four youth had consumed AmED in the previous 12months. AmED users were more likely to engage in all risk behaviours except riding with a drinking driver, relative to youth who only consumed alcohol. No association was observed for youth who consumed alcohol and energy drinks on separate occasions. Youth who use AmED demonstrate a higher risk profile for driving under the influence of alcohol or cannabis, than youth who use alcohol alone. Future research should explore the biopsychosocial pathways that may explain why using energy drinks enhances the already heightened risk posed by alcohol on other health-related behaviours such as driving under the influence. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Optimizing the energy efficiency of capacitive deionization reactors working under real-world conditions.

    Science.gov (United States)

    García-Quismondo, Enrique; Santos, Cleis; Lado, Julio; Palma, Jesús; Anderson, Marc A

    2013-10-15

    Capacitive deionization (CDI) is a rapidly emerging desalination technology that promises to deliver clean water while storing energy in the electrical double layer (EDL) near a charged surface in a capacitive format. Whereas most research in this subject area has been devoted to using CDI for removing salts, little attention has been paid to the energy storage aspect of the technology. However, it is energy storage that would allow this technology to compete with other desalination processes if this energy could be stored and reused efficiently. This requires that the operational aspects of CDI be optimized with respect to energy used both during the removal of ions as well as during the regeneration cycle. This translates into the fact that currents applied during deionization (charging the EDL) will be different from those used in regeneration (discharge). This paper provides a mechanistic analysis of CDI in terms of energy consumption and energy efficiencies during the charging and discharging of the system under several scenarios. In a previous study, we proposed an operational buffer mode in which an effective separation of deionization and regeneration steps would allow one to better define the energy balance of this CDI process. This paper reports on using this concept, for optimizing energy efficiency, as well as to improve upon the electro-adsorption of ions and system lifetime. Results obtained indicate that real-world operational modes of running CDI systems promote the development of new and unexpected behavior not previously found, mainly associated with the inhomogeneous distribution of ions across the structure of the electrodes.

  18. Legislative Framework for Landscape Planning in Latvia

    Science.gov (United States)

    Nitavska, Natalija; Zigmunde, Daiga

    2017-10-01

    With the adoption and the ratification of the European Landscape Convention a legally justified need for a clear landscape policy was grounded in the European countries. It includes the elaboration of the new and the improvement of the existing legislative documents on landscape planning, protection and management. The aim of the particular study is to analyse the existing legislative documents in Latvia influencing landscape planning on different scales / and the implementation of the European Landscape Convention. The study emphasizes the complex structure of the Latvian legislative framework affected by the distribution of the normative documents under the various ministries. Therefore, the main problem is unclear responsibility levels and organizational system for solving the issues regarding landscape planning, protection and management. Thus the various discussions between the involved disciplines and responsible institutions are arising. Two groups of the legislative documents influencing the implementation of the landscape policy in Latvia are detected within the study. The first group is strategic documents determining main landscape planning principles and directions at European, national, regional and professional or sectoral level. The second group is operational documents providing a set of actions for the landscape planning, protection and management at the local or the municipality level. The study concludes that operational documents developed by the municipalities are in high importance because of their direct influence on the landscape planning in Latvia. This often leads to the different landscape planning requirements included in the normative documents of the neighbouring municipalities, although the spatial and ecological borders of the visual landscape do not fit with the formal borders of the municipalities. Thus, it is essential to develop the common principles and actions that would be incumbent on all municipalities to provide the

  19. LANDSCAPE PLANNING IN UKRAINE: THE FIRST LANDSCAPE-PLANNING PROGRAM

    Directory of Open Access Journals (Sweden)

    Leonid Rudenko

    2013-01-01

    Full Text Available The paper presents the results of the first, in Ukraine; project on landscape planning widely accepted in European countries. Under the project implemented in 2010–2013, a landscape-planning program has been developed for the Cherkassy oblast. This is the first document of this kind in Ukraine. The program is mainly based on the experience of the German and Russian schools of landscape planning and on research and assessment conducted by the authors, which allowed identifying approaches to landscape planning, principles of the national policy, and characteristics and potential of environmentally friendly planning in Ukraine. The paper discusses the main phases of the work on the development of the landscape program for the oblast. It also identifies the main stages and key concepts and principles of landscape planning. The paper presents the results of integrated research on the identification and classification of conflicts in land use and the integral concept of the developmental goals for the oblast. The results can be the foundation for adopting management decisions and development of action plans for the lower hierarchal branches.

  20. Bio-energy retains its mitigation potential under elevated CO2.

    Directory of Open Access Journals (Sweden)

    Marion Liberloo

    Full Text Available BACKGROUND: If biofuels are to be a viable substitute for fossil fuels, it is essential that they retain their potential to mitigate climate change under future atmospheric conditions. Elevated atmospheric CO2 concentration [CO2] stimulates plant biomass production; however, the beneficial effects of increased production may be offset by higher energy costs in crop management. METHODOLOGY/MAIN FINDINGS: We maintained full size poplar short rotation coppice (SRC systems under both current ambient and future elevated [CO2] (550 ppm and estimated their net energy and greenhouse gas balance. We show that a poplar SRC system is energy efficient and produces more energy than required for coppice management. Even more, elevated [CO2] will increase the net energy production and greenhouse gas balance of a SRC system with 18%. Managing the trees in shorter rotation cycles (i.e., 2 year cycles instead of 3 year cycles will further enhance the benefits from elevated [CO2] on both the net energy and greenhouse gas balance. CONCLUSIONS/SIGNIFICANCE: Adapting coppice management to the future atmospheric [CO2] is necessary to fully benefit from the climate mitigation potential of bio-energy systems. Further, a future increase in potential biomass production due to elevated [CO2] outweighs the increased production costs resulting in a northward extension of the area where SRC is greenhouse gas neutral. Currently, the main part of the European terrestrial carbon sink is found in forest biomass and attributed to harvesting less than the annual growth in wood. Because SRC is intensively managed, with a higher turnover in wood production than conventional forest, northward expansion of SRC is likely to erode the European terrestrial carbon sink.

  1. Energy indices in irrigated wheat production under conservation and conventional tillage and planting methods

    Directory of Open Access Journals (Sweden)

    S. M Hosseini

    2016-04-01

    Full Text Available Introduction: Conservation tillage system was recommended for soil erosion control in North America for the first time 60 years ago (Wang et al., 2006. Using this tillage system including minimum and zero tillage has been rapidly developed in recent years. Thearea covered by zero tillage in 2006 was 95 million ha all over the world (Dumanski et al., 2006. In addition to saving soil and water resources, conservation tillage system reduces energy consumption and improves energy indices by combining different tillage and planting operations. Results of research conducted in Fars province shows that conservation tillage saves fuel consumption for 77% compared to the conventional system (Afzalinia et al., 2009. Conservation tillage also reduces energy consumption from 23.6 to 42.8% in comparison to the conventional tillage (Rusu, 2005. Since energy indices would be affected by reduced input energies in conservation tillage, this research was conducted to evaluate the effect of different tillage and planting methods on energy inputs and energy indices in irrigated wheat production in Eghlid region. Materials and Methods: This research was performed to evaluate and compare the energy indices in irrigated wheat production under different tillage and planting methods. The study was conducted in the form of a randomized complete block experimental design with five treatments and three replications in Eghlid region. The treatments were included, conventional tillage and seed broadcasting (A, conventional tillage and planting with Machine Barzegar grain drill (B, reduced tillage and seeding with Roto-seeder (C, direct seeding with Jairan Sanaat grain drill (D, and direct seeding with Sfoggia direct drill (E. Experimental plots with 10 by 50 m dimensions were used in this study. Loss crop residues were taken out of the experimental plots and standing crop residues were retained in the plots. In the conventional tillage method, primary tillage was performed

  2. A real options approach to analyse wind energy investments under different support schemes

    DEFF Research Database (Denmark)

    Kitzing, Lena; Juul, Nina; Drud, Michael Stolbjerg Leni

    2016-01-01

    under feed-in tariffs, feed-in premiums and tradable green certificates. Investors can under certificate schemes require up to 3% higher profit margins than under tariffs due to higher variance in profits. Feed-in tariffs may lead to 15% smaller project sizes. This trade-off between faster deployment...... on investment incentives also depends on correlations between the underlying stochastic factors. The results may help investors to make informed investment decisions and policy makers to strategically design renewable support and develop tailor-made incentive schemes.......A real options model is developed to evaluate wind energy investments in a realistic and easily applicable way. Considering optimal investment timing and sizing (capacity choice), the model introduces a capacity constraint as part of the optimisation. Several correlated uncertainty factors...

  3. Research on optimal investment path of transmission corridor under the global energy Internet

    Science.gov (United States)

    Huang, Yuehui; Li, Pai; Wang, Qi; Liu, Jichun; Gao, Han

    2018-02-01

    Under the background of the global energy Internet, the investment planning of transmission corridor from XinJiang to Germany is studied in this article, which passes through four countries: Kazakhstan, Russia, Belarus and Poland. Taking the specific situation of different countries into account, including the length of transmission line, unit construction cost, completion time, transmission price, state tariff, inflation rate and so on, this paper constructed a power transmission investment model. Finally, the dynamic programming method is used to simulate the example, and the optimal strategies under different objective functions are obtained.

  4. Excitation of high energy levels under laser exposure of suspensions of nanoparticles in liquids

    International Nuclear Information System (INIS)

    Shafeev, G.A.; Simakin, A.V.; Bozon-Verduraz, F.; Robert, M.

    2007-01-01

    Laser exposure of suspensions of nanoparticles in liquids leads to excitation of high energy levels in both liquid and nanoparticle material. The emission spectrum of the colloidal solution under exposure of a suspension metallic nanoparticles in water to radiation of a Nd:YAG laser of a picosecond range of pulse duration is discussed. Excitation of nuclear energy levels and neutron release is experimentally studied on the model system of transmutation of Hg into Au that occurs under exposure of Hg nanodrops suspended in D 2 O. The proposed mechanism involves: (i) emission of X-ray photons by Hg nanoparticles upon laser exposure, leading to neutron release from D 2 O, (ii) initiation of Hg → Au transmutation by the capture of neutrons. The effect of transmutation is more pronounced using 196 Hg isotope instead of Hg of natural isotope composition. The influence of laser pulse duration on the degree of transmutation (from fs through ns range) is discussed

  5. Excitation of high energy levels under laser exposure of suspensions of nanoparticles in liquids

    Science.gov (United States)

    Shafeev, G. A.; Simakin, A. V.; Bozon-Verduraz, F.; Robert, M.

    2007-12-01

    Laser exposure of suspensions of nanoparticles in liquids leads to excitation of high energy levels in both liquid and nanoparticle material. The emission spectrum of the colloidal solution under exposure of a suspension metallic nanoparticles in water to radiation of a Nd:YAG laser of a picosecond range of pulse duration is discussed. Excitation of nuclear energy levels and neutron release is experimentally studied on the model system of transmutation of Hg into Au that occurs under exposure of Hg nanodrops suspended in D 2O. The proposed mechanism involves: (i) emission of X-ray photons by Hg nanoparticles upon laser exposure, leading to neutron release from D 2O, (ii) initiation of Hg → Au transmutation by the capture of neutrons. The effect of transmutation is more pronounced using 196Hg isotope instead of Hg of natural isotope composition. The influence of laser pulse duration on the degree of transmutation (from fs through ns range) is discussed.

  6. Biomass Energy for Transport and Electricity: Large scale utilization under low CO2 concentration scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Luckow, Patrick; Wise, Marshall A.; Dooley, James J.; Kim, Son H.

    2010-01-25

    This paper examines the potential role of large scale, dedicated commercial biomass energy systems under global climate policies designed to stabilize atmospheric concentrations of CO2 at 400ppm and 450ppm. We use an integrated assessment model of energy and agriculture systems to show that, given a climate policy in which terrestrial carbon is appropriately valued equally with carbon emitted from the energy system, biomass energy has the potential to be a major component of achieving these low concentration targets. The costs of processing and transporting biomass energy at much larger scales than current experience are also incorporated into the modeling. From the scenario results, 120-160 EJ/year of biomass energy is produced by midcentury and 200-250 EJ/year by the end of this century. In the first half of the century, much of this biomass is from agricultural and forest residues, but after 2050 dedicated cellulosic biomass crops become the dominant source. A key finding of this paper is the role that carbon dioxide capture and storage (CCS) technologies coupled with commercial biomass energy can play in meeting stringent emissions targets. Despite the higher technology costs of CCS, the resulting negative emissions used in combination with biomass are a very important tool in controlling the cost of meeting a target, offsetting the venting of CO2 from sectors of the energy system that may be more expensive to mitigate, such as oil use in transportation. The paper also discusses the role of cellulosic ethanol and Fischer-Tropsch biomass derived transportation fuels and shows that both technologies are important contributors to liquid fuels production, with unique costs and emissions characteristics. Through application of the GCAM integrated assessment model, it becomes clear that, given CCS availability, bioenergy will be used both in electricity and transportation.

  7. Effects of Home Energy Management Systems on Distribution Utilities and Feeders Under Various Market Structures: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Ruth, Mark; Pratt, Annabelle; Lunacek, Monte; Mittal, Saurabh; Wu, Hongyu; Jones, Wesley

    2015-07-17

    The combination of distributed energy resources (DER) and retail tariff structures to provide benefits to both utility consumers and the utilities is poorly understood. To improve understanding, an Integrated Energy System Model (IESM) is being developed to simulate the physical and economic aspects of DER technologies, the buildings where they reside, and feeders servicing them. The IESM was used to simulate 20 houses with home energy management systems on a single feeder under a time of use tariff to estimate economic and physical impacts on both the households and the distribution utilities. HEMS reduce consumers’ electric bills by precooling houses in the hours before peak electricity pricing. Household savings are greater than the reduction utility net revenue indicating that HEMS can provide a societal benefit providing tariffs are structured so that utilities remain solvent. Utilization of HEMS reduce peak loads during high price hours but shifts it to hours with off-peak and shoulder prices and resulting in a higher peak load.

  8. High power and high energy lithium-ion batteries for under-water applications

    Science.gov (United States)

    Gitzendanner, R.; Puglia, F.; Martin, C.; Carmen, D.; Jones, E.; Eaves, S.

    Lithium-ion batteries have demonstrated excellent energy density, reliability, and life in commercial applications. Several new Navy and undersea applications are emerging that need the high energy density and high power capabilities that the lithium-ion technology offers. Such applications have historically utilized silver-zinc technology for their power source. However, life cycle costs, maintenance and logistics issues, and wet-life limitations are true detriments in these applications. Lithium-ion technology has demonstrated the energy and power density of silver-zinc, but with much improved cycle life, shelf life, and low maintenance properties. For these reasons, and others, many under water applications are looking to lithium-ion to provide the performance of the silver-zinc system, but at a greatly reduced life-cycle cost.

  9. Energy consumption of SO2 removal from humid air under electron beam and electric field influence

    International Nuclear Information System (INIS)

    Nichipor, H.; Radjuk, E.; Chmielewski, A.G.; Zimek, Z.

    1998-01-01

    The kinetic of SO 2 oxidation in humid air under influence of electron beam and electrical field was investigated by computer simulation method in steady state and pulse mode. SO 2 oxidation process was stimulated by radical and ion reactions. The calculation model has included 46 different particles and 160 chemical reactions. Gas mixture containing 1000 ppm of SO 2 concentration was investigated at temperature T=67 deg. C and pressure p=1 at. Water content was within the range 2-12%. Electron beam parameters were as follows: average beam current density 0.0032-3,2 mA/cm 2 , pulse duration 400 μs, repetition rate 50 Hz. Electrical field density was E/n =10 -15 Vcm 2 . Electrical pulse duration was changed within the range 5 x10 -7 -10 -5 s. The influence of the parameters of synchronized electron beam and electrical field pulses on energy deposition was under consideration. Energy cost of SO 2 removal on 90% level was estimated in steady state and pulse modes. It was found that total electron beam and electrical field energy losses in pulse mode are 6 times lower to compare with steady state conditions. The optimum of electrical field pulse duration from point of view minimum energy cost of SO 2 removal was found for different electron beam pulse current levels

  10. Resonant energy transfer under the influence of the evanescent field from the metal

    Science.gov (United States)

    Poudel, Amrit; Chen, Xin; Ratner, Mark A.

    2017-06-01

    We present a quantum framework based on a density matrix of a dimer system to investigate the quantum dynamics of excitation energy transfer (EET) in the presence of the evanescent field from the metal and the phonon bath. Due to the spatial correlation of the electric field in the vicinity of the metal, the spectral density of the evanescent field is similar to that of a shared phonon bath. However, the EET dynamics under the influence of the evanescent field is an open and a new problem. Here we use a thin metallic film to investigate the effect of the evanescent field on the excitation energy transfer in a dimer system based on a density matrix approach. Our results indicate that a thin metallic film enhances the energy transfer rate at the expense of absorbing energy during the process. Since the spectral density of the evanescent field is affected by the geometry of the medium and the distance of a dimer system from the medium, our results demonstrate the possibility to tune EET based on material geometry and distances. Our model also serves as an expansion to quantum heat engine models and provides a framework to investigate the EET in light harvesting molecular networks under the influence of the evanescent field.

  11. Decipher the mechanisms of protein conformational changes induced by nucleotide binding through free-energy landscape analysis: ATP binding to Hsp70.

    Directory of Open Access Journals (Sweden)

    Adrien Nicolaï

    Full Text Available ATP regulates the function of many proteins in the cell by transducing its binding and hydrolysis energies into protein conformational changes by mechanisms which are challenging to identify at the atomic scale. Based on molecular dynamics (MD simulations, a method is proposed to analyze the structural changes induced by ATP binding to a protein by computing the effective free-energy landscape (FEL of a subset of its coordinates along its amino-acid sequence. The method is applied to characterize the mechanism by which the binding of ATP to the nucleotide-binding domain (NBD of Hsp70 propagates a signal to its substrate-binding domain (SBD. Unbiased MD simulations were performed for Hsp70-DnaK chaperone in nucleotide-free, ADP-bound and ATP-bound states. The simulations revealed that the SBD does not interact with the NBD for DnaK in its nucleotide-free and ADP-bound states whereas the docking of the SBD was found in the ATP-bound state. The docked state induced by ATP binding found in MD is an intermediate state between the initial nucleotide-free and final ATP-bound states of Hsp70. The analysis of the FEL projected along the amino-acid sequence permitted to identify a subset of 27 protein internal coordinates corresponding to a network of 91 key residues involved in the conformational change induced by ATP binding. Among the 91 residues, 26 are identified for the first time, whereas the others were shown relevant for the allosteric communication of Hsp70 s in several experiments and bioinformatics analysis. The FEL analysis revealed also the origin of the ATP-induced structural modifications of the SBD recently measured by Electron Paramagnetic Resonance. The pathway between the nucleotide-free and the intermediate state of DnaK was extracted by applying principal component analysis to the subset of internal coordinates describing the transition. The methodology proposed is general and could be applied to analyze allosteric communication in

  12. Design of vibratory energy harvesters under stochastic parametric uncertainty: a new optimization philosophy

    International Nuclear Information System (INIS)

    Hosseinloo, Ashkan Haji; Turitsyn, Konstantin

    2016-01-01

    Vibratory energy harvesters as potential replacements for conventional batteries are not as robust as batteries. Their performance can drastically deteriorate in the presence of uncertainty in their parameters. Parametric uncertainty is inevitable with any physical device mainly due to manufacturing tolerances, defects, and environmental effects such as temperature and humidity. Hence, uncertainty propagation analysis and optimization under uncertainty seem indispensable with any energy harvester design. Here we propose a new modeling philosophy for optimization under uncertainty; optimization for the worst-case scenario (minimum power) rather than for the ensemble expectation of the power. The proposed optimization philosophy is practically very useful when there is a minimum requirement on the harvested power. We formulate the problems of uncertainty propagation and optimization under uncertainty in a generic and architecture-independent fashion, and then apply them to a single-degree-of-freedom linear piezoelectric energy harvester with uncertainty in its different parameters. The simulation results show that there is a significant improvement in the worst-case power of the designed harvester compared to that of a naively optimized (deterministically optimized) harvester. For instance, for a 10% uncertainty in the natural frequency of the harvester (in terms of its standard deviation) this improvement is about 570%. (paper)

  13. Exploring the Visual Landscape

    NARCIS (Netherlands)

    Nijhuis, S.; Van Lammeren, R.; Van der Hoeven, F.

    2011-01-01

    Exploring the Visual Landscape is about the combination of landscape research and planning, visual perception and Geographic Information Science. It showcases possible ways of getting a grip on themes like: landscape openness, cluttering of the rural landscape, high-rise buildings in relation to

  14. Key issues review: evolution on rugged adaptive landscapes

    Science.gov (United States)

    Obolski, Uri; Ram, Yoav; Hadany, Lilach

    2018-01-01

    Adaptive landscapes represent a mapping between genotype and fitness. Rugged adaptive landscapes contain two or more adaptive peaks: allele combinations with higher fitness than any of their neighbors in the genetic space. How do populations evolve on such rugged landscapes? Evolutionary biologists have struggled with this question since it was first introduced in the 1930s by Sewall Wright. Discoveries in the fields of genetics and biochemistry inspired various mathematical models of adaptive landscapes. The development of landscape models led to numerous theoretical studies analyzing evolution on rugged landscapes under different biological conditions. The large body of theoretical work suggests that adaptive landscapes are major determinants of the progress and outcome of evolutionary processes. Recent technological advances in molecular biology and microbiology allow experimenters to measure adaptive values of large sets of allele combinations and construct empirical adaptive landscapes for the first time. Such empirical landscapes have already been generated in bacteria, yeast, viruses, and fungi, and are contributing to new insights about evolution on adaptive landscapes. In this Key Issues Review we will: (i) introduce the concept of adaptive landscapes; (ii) review the major theoretical studies of evolution on rugged landscapes; (iii) review some of the recently obtained empirical adaptive landscapes; (iv) discuss recent mathematical and statistical analyses motivated by empirical adaptive landscapes, as well as provide the reader with instructions and source code to implement simulations of evolution on adaptive landscapes; and (v) discuss possible future directions for this exciting field.

  15. Sustaining ecosystem services in cultural landscapes

    DEFF Research Database (Denmark)

    Plieninger, Tobias; van der Horst, Dan; Schleyer, Christian

    2014-01-01

    , but these are under pressure from agricultural intensification, land abandonment, and urbanization. In recent years, the cultural landscapes concept has been broadly adopted in science, policy, and management. The interest in both outstanding and vernacular landscapes finds expression in the UNESCO World Heritage...

  16. Thinking big: linking rivers to landscapes

    Science.gov (United States)

    Joan O’Callaghan; Ashley E. Steel; Kelly M. Burnett

    2012-01-01

    Exploring relationships between landscape characteristics and rivers is an emerging field, enabled by the proliferation of satellite date, advances in statistical analysis, and increased emphasis on large-scale monitoring. Landscapes features such as road networks, underlying geology, and human developments, determine the characteristics of the rivers flowing through...

  17. Optimization of annual energy demand in office buildings under the influence of climate change in Chile

    International Nuclear Information System (INIS)

    Rubio-Bellido, Carlos; Pérez-Fargallo, Alexis; Pulido-Arcas, Jesús A.

    2016-01-01

    Numerous studies about climate change have emerged in recent years because of their potential impact on many activities of human life, amongst which, the building sector is no exception. Changes in climate conditions have a direct influence on the external conditions for buildings and, thus, on their energy demand. In this context, computer aided simulation provides handy tools that help in assessing this impact. This paper investigates climate data for future scenarios and the effect on energy demand in office buildings in Chile. This data has been generated in the 9 climatic zones that are representative of the main inhabited areas, for the years 2020, 2050 and 2080. Predictions have been produced for the acknowledged A2 ‘medium-high’ Greenhouse Gases emissions GHG scenario, pursuant the Intergovernmental Panel on Climate Change (IPCC). The effect of climate change on the energy demand for office buildings is optimized by implementing the calculation procedure of ISO-13790:2008, based on iterations of its envelope and form. As a result, this research clarifies how future climate scenarios will affect the energy demand for different types of office buildings in Chile, and how their shape and enclosure can be optimized. - Highlights: • Forecast of 9 Chilean climate zones under Greenhouse Gases Scenario A2. • Influence of envelope and form on future energy demand in office buildings. • Multiple iterations on Form Ratio (FR) and Window-to-Wall Ratio (WWR). • Optimization in early stages of design considering global warming.

  18. Does inhibition of poly(ADP-ribose) polymerase prevent energy overconsumption under microgravity?

    Science.gov (United States)

    Dobrota, C.; Piso, M. I.; Keul, A.

    When plants are exposed to a stress signal they expend a lot of energy and exhibit enhanced respiration rates This is partially due to a breakdown in the NAD pool caused by the enhanced activity PARP which uses NAD as a substrate to synthesize polymers of ADP-ribose Stress-induced depletion of NAD results in a similar depletion of energy since ATP molecules are required to resynthesize the depleted NAD It seems that plants with lowered poly ADP ribosyl ation activity appear tolerant to multiple stresses Inhibiting PARP activity prevents energy overconsumption under stress allowing normal mitochondrial respiration We intend to study if the microgravity is perceived by plants as a stress factor and if experimental inhibition of poly ADP-ribose polymerase may improve the energetic level of the cells References DeBlock M Verduyn C De Brouwer D and Cornelissen M 2005 Poly ADP-ribose polymerase in plants affects energy homeostasis cell death and stress tolerance The Plant Journal 41 95--106 Huang S Greenway H Colmerm T D and Millar A H 2005 Protein synthesis by rice coleoptiles during prolonged anoxia Implications for glycolysis growth and energy utilization Annals of Botany 96 703--715 Mittler R Vanderauwera S Gollery M and Van Breusegem F 2005 Reactive oxygen gene network of plants Trends in Plant Science 9 10 490-498

  19. Change of Energy of the Cubic Subnanocluster of Iron Under Influence of Interstitial and Substitutional Atoms.

    Science.gov (United States)

    Nedolya, Anatoliy V; Bondarenko, Natalya V

    2016-12-01

    Energy change of an iron face-centred cubic subnanocluster was evaluated using molecular mechanics method depending on the position of a carbon interstitial atom and substitutional atoms of nickel. Calculations of all possible positions of impurity atoms show that the energy change of the system are discrete and at certain positions of the atoms are close to continuous.In terms of energy, when all impurity atoms are on the same edge of an atomic cluster, their positions are more advantageous. The presence of nickel atoms on the edge of a cubic cluster resulted in decrease of potential barrier for a carbon atom and decrease in energy in the whole cluster. A similar drift of a carbon atom from central octahedral interstitial site to the surface in the direction occurred under the influence of surface factors.Such configuration corresponds to decreasing symmetry and increasing the number of possible energy states of a subnanocluster, and it corresponds to the condition of spontaneous crystallization process in an isolated system.Taking into account accidental positions of the nickel atom in the iron cluster, such behaviour of the carbon atom can explain the mechanism of growth of a new phase and formation of new clusters in the presence of other kind of atoms because of surface influence.

  20. Do Geographically Isolated Wetlands Influence Landscape Functions?

    Science.gov (United States)

    Landscape functions such as flow generation, nutrient and sediment retention, and biodiversity support depend on the exchange of solutes, particles, energy, and organisms between elements in hydrological and habitat networks. Wetlands are important network elements, providing hyd...

  1. Second crossover energy of insulating materials using stationary electron beam under normal incidence

    Energy Technology Data Exchange (ETDEWEB)

    Rau, E.I. [Institute of Microelectronics Technology of Russian Academy of Science, 142432 Chernogolovka, Moscow District (Russian Federation)], E-mail: rau@phys.msu.ru; Fakhfakh, S. [LaMaCop, Faculte des Sciences, Route Soukra km 3, BP 802, CP 3018 Sfax (Tunisia); Andrianov, M.V.; Evstafeva, E.N. [Institute of Microelectronics Technology of Russian Academy of Science, 142432 Chernogolovka, Moscow District (Russian Federation); Jbara, O. [UTAP/LASSI, EA 3802, Faculte des Sciences, BP 1039, 51687 Reims Cedex 2 (France)], E-mail: omar.jbara@univ-reims.fr; Rondot, S.; Mouze, D. [UTAP/LASSI, EA 3802, Faculte des Sciences, BP 1039, 51687 Reims Cedex 2 (France)

    2008-03-15

    The purpose of this paper is to give some aspects of charging effects on dielectric materials submitted to continuous electron beam irradiation in a scanning electron microscope (SEM). When the dielectric is irradiated continuously, the so-called total yield approach (TYA) used to predict the sign of the charge appeared on electron irradiated insulators fails because the charge accumulated in the dielectric interferes with the electrons emission processes. Based on previous experimental and theoretical works found in the literature, an analysis of the evolution of the electron yield curves {sigma} = f(E{sub 0}) of insulators during irradiation is given. The aim of this work is firstly to determine experimentally the second crossover energy E{sub 2C} under continuous electron irradiation (charging conditions) and secondly to demonstrate that the charge balance occurs at this beam energy and not at E{sub 2} the energy deduced from non-charging conditions (pulse primary electron beam experiments) as commonly asserted. It is however possible to apply the TYA by substituting the critical energy E{sub 2} for E{sub 2C}. The experimental procedure is based on simultaneous time dependent measurements of surface potential, leakage current and displacement current. The study underlines the difference between the landing energy of primary electrons E{sub L} at the steady state and the second crossover energy, E{sub 2C}, for charged samples. Some preliminary results are also obtained concerning the influence of the incident beam density on the energy E{sub 2C}. The samples used for this study are PMMA, polycrystalline silicone dioxide (p-SiO{sub 2}), polycrystalline alumina (p-Al{sub 2}O{sub 3}) and soda lime glass (SLG)

  2. Second crossover energy of insulating materials using stationary electron beam under normal incidence

    International Nuclear Information System (INIS)

    Rau, E.I.; Fakhfakh, S.; Andrianov, M.V.; Evstafeva, E.N.; Jbara, O.; Rondot, S.; Mouze, D.

    2008-01-01

    The purpose of this paper is to give some aspects of charging effects on dielectric materials submitted to continuous electron beam irradiation in a scanning electron microscope (SEM). When the dielectric is irradiated continuously, the so-called total yield approach (TYA) used to predict the sign of the charge appeared on electron irradiated insulators fails because the charge accumulated in the dielectric interferes with the electrons emission processes. Based on previous experimental and theoretical works found in the literature, an analysis of the evolution of the electron yield curves σ = f(E 0 ) of insulators during irradiation is given. The aim of this work is firstly to determine experimentally the second crossover energy E 2C under continuous electron irradiation (charging conditions) and secondly to demonstrate that the charge balance occurs at this beam energy and not at E 2 the energy deduced from non-charging conditions (pulse primary electron beam experiments) as commonly asserted. It is however possible to apply the TYA by substituting the critical energy E 2 for E 2C . The experimental procedure is based on simultaneous time dependent measurements of surface potential, leakage current and displacement current. The study underlines the difference between the landing energy of primary electrons E L at the steady state and the second crossover energy, E 2C , for charged samples. Some preliminary results are also obtained concerning the influence of the incident beam density on the energy E 2C . The samples used for this study are PMMA, polycrystalline silicone dioxide (p-SiO 2 ), polycrystalline alumina (p-Al 2 O 3 ) and soda lime glass (SLG)

  3. Navigating the Interface Between Landscape Genetics and Landscape Genomics

    Directory of Open Access Journals (Sweden)

    Andrew Storfer

    2018-03-01

    Full Text Available As next-generation sequencing data become increasingly available for non-model organisms, a shift has occurred in the focus of studies of the geographic distribution of genetic variation. Whereas landscape genetics studies primarily focus on testing the effects of landscape variables on gene flow and genetic population structure, landscape genomics studies focus on detecting candidate genes under selection that indicate possible local adaptation. Navigating the transition between landscape genomics and landscape genetics can be challenging. The number of molecular markers analyzed has shifted from what used to be a few dozen loci to thousands of loci and even full genomes. Although genome scale data can be separated into sets of neutral loci for analyses of gene flow and population structure and putative loci under selection for inference of local adaptation, there are inherent differences in the questions that are addressed in the two study frameworks. We discuss these differences and their implications for study design, marker choice and downstream analysis methods. Similar to the rapid proliferation of analysis methods in the early development of landscape genetics, new analytical methods for detection of selection in landscape genomics studies are burgeoning. We focus on genome scan methods for detection of selection, and in particular, outlier differentiation methods and genetic-environment association tests because they are the most widely used. Use of genome scan methods requires an understanding of the potential mismatches between the biology of a species and assumptions inherent in analytical methods used, which can lead to high false positive rates of detected loci under selection. Key to choosing appropriate genome scan methods is an understanding of the underlying demographic structure of study populations, and such data can be obtained using neutral loci from the generated genome-wide data or prior knowledge of a species

  4. Navigating the Interface Between Landscape Genetics and Landscape Genomics.

    Science.gov (United States)

    Storfer, Andrew; Patton, Austin; Fraik, Alexandra K

    2018-01-01

    As next-generation sequencing data become increasingly available for non-model organisms, a shift has occurred in the focus of studies of the geographic distribution of genetic variation. Whereas landscape genetics studies primarily focus on testing the effects of landscape variables on gene flow and genetic population structure, landscape genomics studies focus on detecting candidate genes under selection that indicate possible local adaptation. Navigating the transition between landscape genomics and landscape genetics can be challenging. The number of molecular markers analyzed has shifted from what used to be a few dozen loci to thousands of loci and even full genomes. Although genome scale data can be separated into sets of neutral loci for analyses of gene flow and population structure and putative loci under selection for inference of local adaptation, there are inherent differences in the questions that are addressed in the two study frameworks. We discuss these differences and their implications for study design, marker choice and downstream analysis methods. Similar to the rapid proliferation of analysis methods in the early development of landscape genetics, new analytical methods for detection of selection in landscape genomics studies are burgeoning. We focus on genome scan methods for detection of selection, and in particular, outlier differentiation methods and genetic-environment association tests because they are the most widely used. Use of genome scan methods requires an understanding of the potential mismatches between the biology of a species and assumptions inherent in analytical methods used, which can lead to high false positive rates of detected loci under selection. Key to choosing appropriate genome scan methods is an understanding of the underlying demographic structure of study populations, and such data can be obtained using neutral loci from the generated genome-wide data or prior knowledge of a species' phylogeographic history. To

  5. Water-Energy Nexus Challenges & Opportunities in the Arabian Peninsula under Climate Change

    Science.gov (United States)

    Flores-Lopez, F.; Yates, D. N.; Galaitsi, S.; Binnington, T.; Dougherty, W.; Vinnaccia, M.; Glavan, J. C.

    2016-12-01

    Demand for water in the GCC countries relies mainly on fossil groundwater resources and desalination. Satisfying water demand requires a great deal of energy as it treats and moves water along the supply chain from sources, through treatment processes, and ultimately to the consumer. Hence, there is an inherent connection between water and energy and with climate change, the links between water and energy are expected to become even stronger. As part of AGEDI's Local, National, and Regional Climate Change Programme, a study of the water-energy nexus of the countries in the Arabian Peninsula was implemented. For water, WEAP models both water demand - and its main drivers - and water supply, simulating policies, priorities and preferences. For energy, LEAP models both energy supply and demand, and is able to capture the impacts of low carbon development strategies. A coupled WEAP-LEAP model was then used to evaluate the future performance of the energy-water system under climate change and policy scenarios. The coupled models required detailed data, which were obtained through literature reviews and consultations with key stakeholders in the region. As part of this process, the outputs of both models were validated for historic periods using existing data The models examined 5 policy scenarios of different futures of resource management to the year 2060. A future under current management practices with current climate and a climate projection based on the RCP8.5; a High Efficiency scenario where each country gradually implements policies to reduce the consumption of water and electricity; a Natural Resource Protection scenario with resource efficiency and phasing out of groundwater extraction and drastic reduction of fossil fuel usage in favor of solar; and an Integrated Policy scenario that integrates the prior two policy scenarios Water demands can mostly be met in any scenario through supply combinations of groundwater, desalination and wastewater reuse, with some

  6. Modeling the water-energy nexus under changing energy market and climate conditions: a case study in the Italian Alps

    Science.gov (United States)

    Denaro, Simona; Anghileri, Daniela; Castelletti, Andrea; Fumagalli, Elena; Giuliani, Matteo

    2015-04-01

    Climate change and growing population are expected to severely affect freshwater availability by the end of 21th century. Many river basins, especially in the Mediterranean region, are likely to become more prone to periods of reduced water supply, risking considerable impacts on the society, the environment, and the economy, thus emphasizing the need to rethink the way water resources are distributed, managed, and used at the regional and river basin scale. This paradigm shift will be essential to cope with the undergoing global change, characterized by growing water demands and by increasingly uncertain hydrologic regimes. Most of the literature traditionally focused on predicting the impacts of climate change on water resources, while our understanding of the human footprint on the hydrological cycle is limited. For example, changes in the operation of the Alpine hydropower reservoirs induced by socio-economic drivers (e.g., development of renewable energy) have been already observed over the last few years and have produced relevant impacts on multiple water uses due to the altered distribution of water volumes in time and space. Modeling human decisions as well as the links between society and environmental systems becomes key to develop reliable projections on the co-evolution of the coupled human-water systems and deliver robust adaptation strategies. This work contributes a preliminary model-based analysis of the behaviour of hydropower operators under changing energy market and climate conditions. The proposed approach is developed for the San Giacomo-Cancano reservoir system located in the Lake Como catchment. The identification of the current operating policy is supported by input variable selection methods to select the most relevant hydrological and market based drivers to explain the observed release time series. The identified model is then simulated under a set of future scenarios, accounting for both climate and socio-economic change (e

  7. Influence of Surface Energy Effects on Elastic Fields of a Layered Elastic Medium under Surface Loading

    Directory of Open Access Journals (Sweden)

    Supakorn Tirapat

    2017-01-01

    Full Text Available This paper presents the analysis of a layered elastic half space under the action of axisymmetric surface loading and the influence of the surface energy effects. The boundary value problems for the bulk and the surface are formulated based on classical linear elasticity and a complete Gurtin-Murdoch constitutive relation. An analytical technique using Love’s representation and the Hankel integral transform is employed to derive an integral-form solution for both displacement and stress fields. An efficient numerical quadrature is then applied to accurately evaluate all involved integrals. Selected numerical results are presented to portray the influence of various parameters on elastic fields. Numerical results indicate that the surface stress displays a significant influence on both displacement and stress fields. It is also found that the layered half space becomes stiffer with the presence of surface stresses. In addition, unlike the classical elasticity solution, size-dependent behavior of elastic fields is noted. The present analytical solutions provide fundamental understanding of the influence of surface energy on layered elastic materials. It can also be used as a benchmark solution for the development of numerical techniques such as FEM and BEM, for analysis of more complex problems involving a layered medium under the influence of surface energy effects.

  8. Impact-Based Electromagnetic Energy Harvester with High Output Voltage under Low-Level Excitations

    Directory of Open Access Journals (Sweden)

    Qian Luo

    2017-11-01

    Full Text Available To expand the applications of vibrational energy harvesters (VEHs as power sources of wireless sensor nodes, it is of significance to improve the scavenging efficiency for the broadband, low-frequency, and low-level vibrational energy. The output voltages of electromagnetic vibrational energy harvesters (EMVEHs are usually low, which complicates the power management circuit by an indispensable voltage boosting element. To this end, an impact-based non-resonant EMVEH mainly composed of an outer frame and an inner frame on rollers is proposed. Numerical simulations based on a mathematical model of the harvester are conducted to analyze the effects of structural parameters on the output performance. Under base excitation of 0.1 and 0.3 (where g is the gravitational acceleration, 1 g = 9.8 m · s − 2 , the experimental maximum root mean square voltages of a harvester prototype across a resistor of 11 kΩ are as high as 7.6 and 16.5 V at 6.0 and 8.5 Hz, respectively, with the maximum output powers of 5.3 and 24.8 mW, or the power densities of 54.6 and 256 μW cm−3. By using a management circuit without a voltage boosting element, a wireless sensor node driven by the prototype can measure and transmit the temperature and humidity every 20 s under base excitation of 0.1 g at 5.4 Hz.

  9. Watershed response and land energy feedbacks under climate change depend upon groundwater.

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, R M; Kollet, S J

    2008-06-10

    Human induced climate change will have a significant impact on the hydrologic cycle, creating changes in fresh water resources, land cover, and feedbacks that are difficult to characterize, which makes it an issue of global importance. Previous studies have not included subsurface storage in climate change simulations and feedbacks. A variably-saturated groundwater flow model with integrated overland flow and land surface model processes is used to examine the interplay between coupled water and energy processes under climate change conditions. A case study from the Southern Great Plains (SGP) USA, an important agricultural region that is susceptible to drought, is used as the basis for three scenarios simulations using a modified atmospheric forcing dataset to reflect predicted effects due to human-induced climate change. These scenarios include an increase in the atmospheric temperature and variations in rainfall amount and are compared to the present-day climate case. Changes in shallow soil saturation and groundwater levels are quantified as well as the corresponding energy fluxes at the land surface. Here we show that groundwater and subsurface lateral flow processes are critical in understanding hydrologic response and energy feedbacks to climate change and that certain regions are more susceptible to changes in temperature, while others to changes in precipitation. This groundwater control is critical for understanding recharge and drought processes, possible under future climate conditions.

  10. How wind power landscapes change

    DEFF Research Database (Denmark)

    Möller, Bernd

    2006-01-01

    viewsheds are computed for a variety of thresholds of visual impact, and since overlaid with population and land use data. The results indicate that the construction of new turbines replacing 40% of the old turbine stock and raising the installed capacity by 20% will not add to the comparative impact......Following 25 years of continuous development, Danish wind energy landscapes are going to face changes. Ceased on-shore construction, unresolved re-powering and stalled regional planning characterize the situation overshadowed by off-shore development. One of the factors inhibiting development...... appears to be planning uncertainty regarding the future impact on landscapes. Visual impact has seldom been an issue so far, but growing turbine size and less local involvement may change this. This paper presents a deterministic approach of quantifying percieved visual impact on landscapes and population...

  11. 10 CFR 30.12 - Persons using byproduct material under certain Department of Energy and Nuclear Regulatory...

    Science.gov (United States)

    2010-01-01

    ... of Energy and Nuclear Regulatory Commission contracts. 30.12 Section 30.12 Energy NUCLEAR REGULATORY... Persons using byproduct material under certain Department of Energy and Nuclear Regulatory Commission... accomplished without undue risk to the public health and safety. [40 FR 8784, Mar. 3, 1975, as amended at 43 FR...

  12. Buildings Interoperability Landscape

    Energy Technology Data Exchange (ETDEWEB)

    Hardin, Dave [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephan, Eric G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Weimin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Corbin, Charles D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Widergren, Steven E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-12-31

    Through its Building Technologies Office (BTO), the United States Department of Energy’s Office of Energy Efficiency and Renewable Energy (DOE-EERE) is sponsoring an effort to advance interoperability for the integration of intelligent buildings equipment and automation systems, understanding the importance of integration frameworks and product ecosystems to this cause. This is important to BTO’s mission to enhance energy efficiency and save energy for economic and environmental purposes. For connected buildings ecosystems of products and services from various manufacturers to flourish, the ICT aspects of the equipment need to integrate and operate simply and reliably. Within the concepts of interoperability lie the specification, development, and certification of equipment with standards-based interfaces that connect and work. Beyond this, a healthy community of stakeholders that contribute to and use interoperability work products must be developed. On May 1, 2014, the DOE convened a technical meeting to take stock of the current state of interoperability of connected equipment and systems in buildings. Several insights from that meeting helped facilitate a draft description of the landscape of interoperability for connected buildings, which focuses mainly on small and medium commercial buildings. This document revises the February 2015 landscape document to address reviewer comments, incorporate important insights from the Buildings Interoperability Vision technical meeting, and capture thoughts from that meeting about the topics to be addressed in a buildings interoperability vision. In particular, greater attention is paid to the state of information modeling in buildings and the great potential for near-term benefits in this area from progress and community alignment.

  13. Polymers under ionizing radiation: the study of energy transfers to radiation induced defects

    International Nuclear Information System (INIS)

    Ventura, A.

    2013-01-01

    Radiation-induced defects created in polymers submitted to ionizing radiations, under inert atmosphere, present the same trend as a function of the dose. When the absorbed dose increases, their concentrations increase then level off. This behavior can be assigned to energy transfers from the polymer to the previously created macromolecular defects; the latter acting as energy sinks. During this thesis, we aimed to specify the influence of a given defect, namely the trans-vinylene, in the behavior of polyethylene under ionizing radiations. For this purpose, we proposed a new methodology based on the specific insertion, at various concentrations, of trans-vinylene groups in the polyethylene backbone through chemical synthesis. This enables to get rid of the variety of created defects on one hand and on the simultaneity of their creation on the other hand. Modified polyethylenes, containing solely trans-vinylene as odd groups, were irradiated under inert atmosphere, using either low LET beams (gamma, beta) or high LET beams (swift heavy ions). During irradiations, both macromolecular defects and H 2 emission were quantified. According to experimental results, among all defects, the influence of the trans-vinylene on the behavior of polyethylene is predominant. (author) [fr

  14. Nonlinear dynamic analysis of cantilevered piezoelectric energy harvesters under simultaneous parametric and external excitations

    Science.gov (United States)

    Fang, Fei; Xia, Guanghui; Wang, Jianguo

    2018-02-01

    The nonlinear dynamics of cantilevered piezoelectric beams is investigated under simultaneous parametric and external excitations. The beam is composed of a substrate and two piezoelectric layers and assumed as an Euler-Bernoulli model with inextensible deformation. A nonlinear distributed parameter model of cantilevered piezoelectric energy harvesters is proposed using the generalized Hamilton's principle. The proposed model includes geometric and inertia nonlinearity, but neglects the material nonlinearity. Using the Galerkin