WorldWideScience

Sample records for surface storage dynamics

  1. Surface freshwater storage and dynamics in the Amazon basin during the 2005 exceptional drought

    International Nuclear Information System (INIS)

    Frappart, Frédéric; Ramillien, Guillaume; Papa, Fabrice; Calmant, Stéphane; Santos da Silva, Joecila; Prigent, Catherine; Seyler, Frédérique

    2012-01-01

    The Amazon river basin has been recently affected by extreme climatic events, such as the exceptional drought of 2005, with significant impacts on human activities and ecosystems. In spite of the importance of monitoring freshwater stored and moving in such large river basins, only scarce measurements of river stages and discharges are available and the signatures of extreme drought conditions on surface freshwater dynamics at the basin scale are still poorly known. Here we use continuous multisatellite observations of inundation extent and water levels between 2003 and 2007 to monitor monthly variations of surface water storage at the basin scale. During the 2005 drought, the amount of water stored in the river and floodplains of the Amazon basin was ∼130 km 3 (∼70%) below its 2003–7 average. This represents almost a half of the anomaly of minimum terrestrial water stored in the basin as estimated using the Gravity Recovery and Climate Experiment (GRACE) data. (letter)

  2. Full Scale Investigation of the Dynamic Heat Storage of Concrete Decks with PCM and Enhanced Heat Transfer Surface Area

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2013-01-01

    The paper presents the full-scale experimental investigation of the dynamic heat storage potential of the prefabricated hollow core deck elements with and without phase change material (PCM) and with and without increased bottom surface area of the decks. In the presented investigation five types...... of hollow core decks with different surfaces on the bottom are investigated: reference deck made of standard concrete and flat surface, deck with special mortar grooved tiles, deck with flat mortar tiles, deck with grooved mortar and phase change material tiles, deck with flat mortar and phase change...... material tiles. The experimental investigation presented in the paper is performed in the specially designed modified hot box apparatus that allows maintaining periodic steady-state tests with the full-scale concrete deck elements. The presented research investigates if the extended surface area and PCM...

  3. Investigation of cryogenic hydrogen storage on high surface area activated carbon. Equilibrium and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Paggiaro, Ricardo Gaspar

    2008-11-29

    This thesis investigates cryo-adsorptive systems for hydrogen storage for mobile applications. By means of macroscopic and microscopic balance models, an extensive analysis is carried out, including among others the investigation of the thermal effects during high-pressure system filling, venting losses during normal operation and inactivity, time-course of system pressure and temperature and gas delivery under various operating conditions. Model results were compared with experimental data, good agreement was obtained. The analysis also includes a comparison to other storage technologies such as cryo-compressed gas and liquefaction storage. The results show that cryo-adsorptive systems have storage characteristics comparable to compressed gas systems, but at a much lower pressure. They are also energetically more efficient than liquid hydrogen systems. However, the necessity of cryotemperatures and thermal management during operation and filling might limit their application. (orig.)

  4. Longitudinal dynamics in storage rings

    International Nuclear Information System (INIS)

    Colton, E.P.

    1986-01-01

    The single-particle equations of motion are derived for charged particles in a storage ring. Longitudinal space charge is included in the potential assuming an infinitely conducting circular beam pipe with a distributed inductance. The framework uses Hamilton's equations with the canonical variables phi and W. The Twiss parameters for longitudinal motion are also defined for the small amplitude synchrotron oscillations. The space-charge Hamiltonian is calculated for both parabolic bunches and ''matched'' bunches. A brief analysis including second-harmonic rf contributions is also given. The final sections supply calculations of dynamical quantities and particle simulations with the space-charge effects neglected

  5. Identifying the Dynamic Catchment Storage That Does Not Drive Runoff

    Science.gov (United States)

    Dralle, D.; Hahm, W. J.; Rempe, D.; Karst, N.; Thompson, S. E.; Dietrich, W. E.

    2017-12-01

    The central importance of subsurface water storage in hydrology has resulted in numerous attempts to develop hydrograph and mass balance based techniques to quantify catchment storage state or capacity. In spite of these efforts, relatively few studies have linked catchment scale storage metrics to Critical Zone (CZ) structure and the status of water in hillslopes. Elucidating these relationships would increase the interpretability of catchment storage metrics, and aid the development of hydrologic models. Here, we propose that catchment storage consists of a dynamic component that varies on seasonal timescales, and a static component with negligible time variation. Discharge is assumed to be explicitly sensitive to changes in some fraction of the dynamic storage, while the remaining dynamic storage varies without directly influencing flow. We use a coupled mass balance and storage-discharge function approach to partition dynamic storage between these driving and non-driving storage pools, and compare inferences with direct observations of saturated and unsaturated dynamic water storages at two field sites in Northern California. We find that most dynamic catchment water storage does not drive streamflow in both sites, even during the wettest times of year. Moreover, the physical character of non-driving dynamic storage depends strongly on catchment CZ structure. At a site with a deep profile of weathered rock, the dynamic storage that drives streamflow occurs as a seasonally perched groundwater table atop fresh bedrock, and that which does not drive streamflow resides as seasonally dynamic unsaturated water in shallow soils and deep, weathered rock. At a second site with a relatively thin weathered zone, water tables rapidly rise to intersect the ground surface with the first rains of the wet season, yet only a small fraction of this dynamic saturated zone storage drives streamflow. Our findings emphasize how CZ structure governs the overlap in time and space of

  6. Storage fee analysis for a retrievable surface storage facility

    International Nuclear Information System (INIS)

    Field, B.B.; Rosnick, C.K.

    1973-12-01

    Conceptual design studies are in progress for a Water Basin Concept (WBC) and an alternative Sealed Storage Cask Concept (SSCC) of a Retrievable Surface Storage Facility (RSSF) intended as a Federal government facility for storing high-level radioactive wastes until a permanent disposal method is established. The RSSF will be a man-made facility with a design life of at least 100 y, and will have capacity to store all of the high-level waste from the reprocessing of nuclear power plant spent fuels generated by the industry through the year 2000. This report is a basic version of ARH-2746, ''Retrievable Surface Storage Facility, Water Basin Concept, User Charge Analysis.'' It is concerned with the issue of establishing a fee to cover the cost of storing nuclear wastes both in the RSSF and at the subsequent disposal facility. (U.S.)

  7. Nonlinear dynamics aspects of modern storage rings

    International Nuclear Information System (INIS)

    Helleman, R.H.G.; Kheifets, S.A.

    1986-01-01

    It is argued that the nonlinearity of storage rings becomes an essential problem as the design parameters of each new machine are pushed further and further. Yet the familiar methods of classical mechanics do not allow determination of single particle orbits over reasonable lengths of time. It is also argued that the single particle dynamics of a storage ring is possibly one of the cleanest and simplest nonlinear dynamical systems available with very few degrees of freedom. Hence, reasons are found for accelerator physicists to be interested in nonlinear dynamics and for researchers in nonlinear dynamics to be interested in modern storage rings. The more familiar methods of treating nonlinear systems routinely used in acclerator theory are discussed, pointing out some of their limitations and pitfalls. 39 refs., 1 fig

  8. Synthesis long life storage studies surface storage of vitrified wastes

    International Nuclear Information System (INIS)

    Beziat, A.; Breton, E.; Ranc, G.; Gaillard, J.P.; Lagrave, H.; Hollender, F.; Jourdain, F.; Piault, E.; Garnier, J.; Lamare, V.; Duret, B.; Helie, M.; Ferry, C.; Mijuin, D.; Gagnier, E.

    2004-01-01

    This document is realized in the framework of the axis 3 of the law of 1991 on the radioactive wastes management. It justifies the choices concerning long time surface storage installation of vitrified wastes, called high activity wastes. The long time of the installation would reach 300 years at the maximum. These wastes represent 1 % at the maximum, of radioactive wastes in France but 95 % of the whole radioactivity. Three main objectives were followed: provide a permanent containment of radionuclides; give the possibility of wastes containers retrieval at all the time; minimize the maintenance and the control. The results allow to conclude that the long time surface storage of high activity wastes is feasible. (A.L.B.)

  9. Nonlinear dynamics aspects of modern storage rings

    International Nuclear Information System (INIS)

    Helleman, R.H.G.; Kheifets, S.A.

    1986-01-01

    The authors try to address the following two questions: a. Why should accelerator physicists to be interested in the recent, sometimes abstract, developments in Nonlinear Dynamics, a field which will recently was mainly studied by mathematicians, theoretical physicists and astronomers? That such an interest to some extent already exists is apparent from the fact that many accelerator physicists attended this School and several analogous meetings in the past. b. Why should researchers from nonlinear dynamics be interested in modern Storage Rings which are largely designed and built by experimental physicists and engineers? At the moment few 'nonlinear scientists' work on storage rings (or in the field of accelerator physics). It is a hopeful sign that many (more) attended this School

  10. Dynamic federation of grid and cloud storage

    Science.gov (United States)

    Furano, Fabrizio; Keeble, Oliver; Field, Laurence

    2016-09-01

    The Dynamic Federations project ("Dynafed") enables the deployment of scalable, distributed storage systems composed of independent storage endpoints. While the Uniform Generic Redirector at the heart of the project is protocol-agnostic, we have focused our effort on HTTP-based protocols, including S3 and WebDAV. The system has been deployed on testbeds covering the majority of the ATLAS and LHCb data, and supports geography-aware replica selection. The work done exploits the federation potential of HTTP to build systems that offer uniform, scalable, catalogue-less access to the storage and metadata ensemble and the possibility of seamless integration of other compatible resources such as those from cloud providers. Dynafed can exploit the potential of the S3 delegation scheme, effectively federating on the fly any number of S3 buckets from different providers and applying a uniform authorization to them. This feature has been used to deploy in production the BOINC Data Bridge, which uses the Uniform Generic Redirector with S3 buckets to harmonize the BOINC authorization scheme with the Grid/X509. The Data Bridge has been deployed in production with good results. We believe that the features of a loosely coupled federation of open-protocolbased storage elements open many possibilities of smoothly evolving the current computing models and of supporting new scientific computing projects that rely on massive distribution of data and that would appreciate systems that can more easily be interfaced with commercial providers and can work natively with Web browsers and clients.

  11. Dynamics of H2 on Ti/Al(100) surfaces

    NARCIS (Netherlands)

    Chen, Jian-Cheng

    2011-01-01

    What is the catalytic role played by titanium in the hydrogen storage material NaAlH4? This thesis aims at unraveling the dynamics of an elementary reaction: H2 dissociation on Ti/Al(100) surfaces. Although this reaction is not the rate limiting step in the hydrogen storage of NaAlH4, it is an

  12. Dynamical speckles in watery surfaces

    International Nuclear Information System (INIS)

    Llovera-Gonzalez, J.J.; Moreno-Yeras, A.; Garcia-Diaz, M.; Alvarez-Salgado, Y.

    2009-01-01

    Recovery of watery surfaces with monolayer of surfactant substances is of interest in diverse technological applications. The format ion and study of molecular monolayer deposited in these surfaces require the application of measurements techniques that allow evaluating the recovery grade locally without modifying practically the studied surface. In this paper the preliminary results obtained by the authors it plows exposed applying the technique of dynamic speckle interferometry in watery surfaces and their consideration like to possible resource to measure the grade of local recovery of these surfaces on the it bases that the speckles pattern dog reveal the dynamics of evaporation that takes place in the same ones. (Author)

  13. Stochastic beam dynamics in storage rings

    International Nuclear Information System (INIS)

    Pauluhn, A.

    1993-12-01

    In this thesis several approaches to stochastic dynamics in storage rings are investigated. In the first part the theory of stochastic differential equations and Fokker-Planck equations is used to describe the processes which have been assumed to be Markov processes. The mathematical theory of Markov processes is well known. Nevertheless, analytical solutions can be found only in special cases and numerical algorithms are required. Several numerical integration schemes for stochastic differential equations will therefore be tested in analytical solvable examples and then applied to examples from accelerator physics. In particular the stochastically perturbed synchrotron motion is treated. For the special case of a double rf system several perturbation theoretical methods for deriving the Fokker-Planck equation in the action variable are used and compared with numerical results. The second part is concerned with the dynamics of electron storage rings. Due to the synchrotron radiation the electron motion is influenced by damping and exciting forces. An algorithm for the computation of the density function in the phase space of such a dissipative stochastically excited system is introduced. The density function contains all information of a process, e.g. it determines the beam dimensions and the lifetime of a stored electron beam. The new algorithm consists in calculating a time propagator for the density function. By means of this propagator the time evolution of the density is modelled very computing time efficient. The method is applied to simple models of the beam-beam interaction (one-dimensional, round beams) and the results of the density calculations are compared with results obtained from multiparticle tracking. Furthermore some modifications of the algorithm are introduced to improve its efficiency concerning computing time and storage requirements. Finally, extensions to two-dimensional beam-beam models are described. (orig.)

  14. Documentation of the dynamic parameter, water-use, stream and lake flow routing, and two summary output modules and updates to surface-depression storage simulation and initial conditions specification options with the Precipitation-Runoff Modeling System (PRMS)

    Science.gov (United States)

    Regan, R. Steve; LaFontaine, Jacob H.

    2017-10-05

    This report documents seven enhancements to the U.S. Geological Survey (USGS) Precipitation-Runoff Modeling System (PRMS) hydrologic simulation code: two time-series input options, two new output options, and three updates of existing capabilities. The enhancements are (1) new dynamic parameter module, (2) new water-use module, (3) new Hydrologic Response Unit (HRU) summary output module, (4) new basin variables summary output module, (5) new stream and lake flow routing module, (6) update to surface-depression storage and flow simulation, and (7) update to the initial-conditions specification. This report relies heavily upon U.S. Geological Survey Techniques and Methods, book 6, chapter B7, which documents PRMS version 4 (PRMS-IV). A brief description of PRMS is included in this report.

  15. Dynamical triangulated fermionic surfaces

    International Nuclear Information System (INIS)

    Ambjoern, J.; Varsted, S.

    1990-12-01

    We perform Monte Carlo simulations of randomly triangulated random surfaces which have fermionic world-sheet scalars θ i associated with each vertex i in addition to the usual bosonic world-sheet scalar χ i μ . The fermionic degrees of freedom force the internal metrics of the string to be less singular than the internal metric of the pure bosonic string. (orig.)

  16. Near surface spent fuel storage: environmental issues

    International Nuclear Information System (INIS)

    Nelson, I.C.; Shipler, D.B.; McKee, R.W.; Glenn, R.D.

    1979-01-01

    Interim storage of spent fuel appears inevitable because of the lack of reprocessing plants and spent fuel repositories. This paper examines the environmental issues potentially associated with management of spent fuel before disposal or reprocessing in a reference scenario. The radiological impacts of spent fuel storage are limited to low-level releases of noble gases and iodine. Water needed for water basin storage of spent fuel and transportation accidents are considered; the need to minimize the distance travelled is pointed out. Resource commitments for construction of the storage facilities are analyzed

  17. Retrievable surface storage: interim storage of solidified high-level waste

    International Nuclear Information System (INIS)

    LaRiviere, J.R.; Nelson, D.C.

    1976-01-01

    Studies have been conducted on retrievable-surface-storage concepts for the interim storage of solidified high-level wastes. These studies have been reviewed by the Panel on Engineered Storage, convened by the Committee on Radioactive Waste Management of the National Research Council-National Academy of Sciences. The Panel has concluded that ''retrievable surface storage is an acceptable interim stage in a comprehensive system for managing high-level radioactive wastes.'' The scaled storage cask concept, which was recommended by the Panel on Engineered Storage, consists of placing a canister of waste inside a carbon-steel cask, which in turn is placed inside a thick concrete cylinder. The waste is cooled by natural convection air flow through an annulus between the cask and the inner wall of the concrete cylinder. The complete assembly is placed above ground in an outdoor storage area

  18. Surface sterilization and duration of seed storage influenced ...

    African Journals Online (AJOL)

    The effects of factorial combinations of four storage duration (in days after seed extraction) and surface sterilization with three dilution levels of sodium hypochlorite on seedling emergence and seedling quality of African breadfruit were studied. Storage duration significantly influenced days to seedling emergence, ...

  19. Sequencing dynamic storage systems with multiple lifts and shuttles

    NARCIS (Netherlands)

    Carlo, Hector J.; Vis, Iris F. A.

    2012-01-01

    New types of Automated Storage and Retrieval Systems (AS/RS) able to achieve high throughput are continuously being developed and require new control polices to take full advantage of the developed system. In this paper, a dynamic storage system has been studied as developed by Vanderlande

  20. The global distribution and dynamics of surface soil moisture

    Science.gov (United States)

    McColl, Kaighin A.; Alemohammad, Seyed Hamed; Akbar, Ruzbeh; Konings, Alexandra G.; Yueh, Simon; Entekhabi, Dara

    2017-01-01

    Surface soil moisture has a direct impact on food security, human health and ecosystem function. It also plays a key role in the climate system, and the development and persistence of extreme weather events such as droughts, floods and heatwaves. However, sparse and uneven observations have made it difficult to quantify the global distribution and dynamics of surface soil moisture. Here we introduce a metric of soil moisture memory and use a full year of global observations from NASA's Soil Moisture Active Passive mission to show that surface soil moisture--a storage believed to make up less than 0.001% of the global freshwater budget by volume, and equivalent to an, on average, 8-mm thin layer of water covering all land surfaces--plays a significant role in the water cycle. Specifically, we find that surface soil moisture retains a median 14% of precipitation falling on land after three days. Furthermore, the retained fraction of the surface soil moisture storage after three days is highest over arid regions, and in regions where drainage to groundwater storage is lowest. We conclude that lower groundwater storage in these regions is due not only to lower precipitation, but also to the complex partitioning of the water cycle by the surface soil moisture storage layer at the land surface.

  1. Terrestrial carbon storage dynamics: Chasing a moving target

    Science.gov (United States)

    Luo, Y.; Shi, Z.; Jiang, L.; Xia, J.; Wang, Y.; Kc, M.; Liang, J.; Lu, X.; Niu, S.; Ahlström, A.; Hararuk, O.; Hastings, A.; Hoffman, F. M.; Medlyn, B. E.; Rasmussen, M.; Smith, M. J.; Todd-Brown, K. E.; Wang, Y.

    2015-12-01

    Terrestrial ecosystems have been estimated to absorb roughly 30% of anthropogenic CO2 emissions. Past studies have identified myriad drivers of terrestrial carbon storage changes, such as fire, climate change, and land use changes. Those drivers influence the carbon storage change via diverse mechanisms, which have not been unified into a general theory so as to identify what control the direction and rate of terrestrial carbon storage dynamics. Here we propose a theoretical framework to quantitatively determine the response of terrestrial carbon storage to different exogenous drivers. With a combination of conceptual reasoning, mathematical analysis, and numeric experiments, we demonstrated that the maximal capacity of an ecosystem to store carbon is time-dependent and equals carbon input (i.e., net primary production, NPP) multiplying by residence time. The capacity is a moving target toward which carbon storage approaches (i.e., the direction of carbon storage change) but usually does not attain. The difference between the capacity and the carbon storage at a given time t is the unrealized carbon storage potential. The rate of the storage change is proportional to the magnitude of the unrealized potential. We also demonstrated that a parameter space of NPP, residence time, and carbon storage potential can well characterize carbon storage dynamics quantified at six sites ranging from tropical forests to tundra and simulated by two versions (carbon-only and coupled carbon-nitrogen) of the Australian Community Atmosphere-Biosphere Land Ecosystem (CABLE) Model under three climate change scenarios (CO2 rising only, climate warming only, and RCP8.5). Overall this study reveals the unified mechanism unerlying terrestrial carbon storage dynamics to guide transient traceability analysis of global land models and synthesis of empirical studies.

  2. Dynamical modeling of surface tension

    International Nuclear Information System (INIS)

    Brackbill, J.U.; Kothe, D.B.

    1996-01-01

    In a recent review it is said that free-surface flows ''represent some of the difficult remaining challenges in computational fluid dynamics''. There has been progress with the development of new approaches to treating interfaces, such as the level-set method and the improvement of older methods such as the VOF method. A common theme of many of the new developments has been the regularization of discontinuities at the interface. One example of this approach is the continuum surface force (CSF) formulation for surface tension, which replaces the surface stress given by Laplace's equation by an equivalent volume force. Here, we describe how CSF might be made more useful. Specifically, we consider a derivation of the CSF equations from a minimization of surface energy as outlined by Jacqmin. This reformulation suggests that if one eliminates the computation of curvature in terms of a unit normal vector, parasitic currents may be eliminated For this reformulation to work, it is necessary that transition region thickness be controlled. Various means for this, in addition to the one discussed by Jacqmin are discussed

  3. Dust Dynamics Near Planetary Surfaces

    Science.gov (United States)

    Colwell, Joshua; Hughes, Anna; Grund, Chris

    Observations of a lunar "horizon glow" by several Surveyor spacecraft in the 1960s opened the study of the dynamics of charged dust particles near planetary surfaces. The surfaces of the Moon and other airless planetary bodies in the solar system (asteroids, and other moons) are directly exposed to the solar wind and ionizing solar ultraviolet radiation, resulting in a time-dependent electric surface potential. Because these same objects are also exposed to bombardment by micrometeoroids, the surfaces are usually characterized by a power-law size distribution of dust that extends to sub-micron-sized particles. Individual particles can acquire a charge different from their surroundings leading to electrostatic levitation. Once levitated, particles may simply return to the surface on nearly ballistic trajectories, escape entirely from the moon or asteroid if the initial velocity is large, or in some cases be stably levitated for extended periods of time. All three outcomes have observable consequences. Furthermore, the behavior of charged dust near the surface has practical implications for planned future manned and unmanned activities on the lunar surface. Charged dust particles also act as sensitive probes of the near-surface plasma environment. Recent numerical modeling of dust levitation and transport show that charged micron-sized dust is likely to accumulate in topographic lows such as craters, providing a mechanism for the creation of dust "ponds" observed on the asteroid 433 Eros. Such deposition can occur when particles are supported by the photoelectron sheath above the dayside and drift over shadowed regions of craters where the surface potential is much smaller. Earlier studies of the lunar horizon glow are consistent with those particles being on simple ballistic trajectories following electrostatic launching from the surface. Smaller particles may be accelerated from the lunar surface to high altitudes consistent with observations of high altitude

  4. Measurement of Dynamic Friction Coefficient on the Irregular Free Surface

    International Nuclear Information System (INIS)

    Yeom, S. H.; Seo, K. S.; Lee, J. H.; Lee, K. H.

    2007-01-01

    A spent fuel storage cask must be estimated for a structural integrity when an earthquake occurs because it freely stands on ground surface without a restriction condition. Usually the integrity estimation for a seismic load is performed by a FEM analysis, the friction coefficient for a standing surface is an important parameter in seismic analysis when a sliding happens. When a storage cask is placed on an irregular ground surface, measuring a friction coefficient of an irregular surface is very difficult because the friction coefficient is affected by the surface condition. In this research, dynamic friction coefficients on the irregular surfaces between a concrete cylinder block and a flat concrete slab are measured with two methods by one direction actuator

  5. 78 FR 70076 - Aging Management of Internal Surfaces, Fire Water Systems, Atmospheric Storage Tanks, and...

    Science.gov (United States)

    2013-11-22

    ... Systems, Atmospheric Storage Tanks, and Corrosion Under Insulation AGENCY: Nuclear Regulatory Commission... Internal Surfaces, Fire Water Systems, Atmospheric Storage Tanks, and Corrosion Under Insulation.'' This LR... related to internal surface aging effects, fire water systems, atmospheric storage tanks, and corrosion...

  6. Synthesis of long live storage studies surface storage of MA-VL wastes

    International Nuclear Information System (INIS)

    Hollender, F.; Jourdain, F.; Piault, E.; Blanchet, Y.; Avakian, G.; Goger, F.; Caillaud, J.; Devictor, N.; Bary, B.; Moitier, C.; Breton, E.; Ranc, G.; Gaillard, J.P.; Lagrave, H.

    2004-01-01

    This document is realized in the framework of the axis 3 of the law of 1991 on the radioactive wastes management. It presents a long time surface storage installation of medium activity long life wastes. The long time of the installation would reach 300 years at the maximum. The feasibility is demonstrated and the design choices are presented and justified. The specific points of the long time storage installation, which are different from a classical industrial storage installation, are also discussed. (A.L.B.)

  7. Some topics in beam dynamics of storage rings

    International Nuclear Information System (INIS)

    Mais, H.

    1996-06-01

    In the following report we want to review some beam dynamics problems in accelerator physics. Theoretical tools and methods are introduced and discussed, and it is shown how these concepts can be applied to the study of various problems in storage rings. The first part treats Hamiltonian systems (proton accelerators) whereas the second part is concerned with explicitly stochastic systems (e.g. electron storage rings). (orig.)

  8. Surface-enhanced raman optical data storage system

    Science.gov (United States)

    Vo-Dinh, Tuan

    1994-01-01

    An improved Surface-Enhanced Raman Optical Data Storage System (SERODS) is disclosed. In the improved system, entities capable of existing in multiple reversible states are present on the storage device. Such entities result in changed Surface-Enhanced Raman Scattering (SERS) when localized state changes are effected in less than all of the entities. Therefore, by changing the state of entities in localized regions of a storage device, the SERS emissions in such regions will be changed. When a write-on device is controlled by a data signal, such a localized regions of changed SERS emissions will correspond to the data written on the device. The data may be read by illuminating the surface of the storage device with electromagnetic radiation of an appropriate frequency and detecting the corresponding SERS emissions. Data may be deleted by reversing the state changes of entities in regions where the data was initially written. In application, entities may be individual molecules which allows for the writing of data at the molecular level. A read/write/delete head utilizing near-field quantum techniques can provide for a write/read/delete device capable of effecting state changes in individual molecules, thus providing for the effective storage of data at the molecular level.

  9. 100KE/KW fuel storage basin surface volumetric factors

    International Nuclear Information System (INIS)

    Conn, K.R.

    1996-01-01

    This Supporting Document presents calculations of surface Volumetric factors for the 100KE and 100KW Fuel Storage Basins. These factors relate water level changes to basin loss or additions of water, or the equivalent water displacement volumes of objects added to or removed from the basin

  10. Reduction in Surface Ocean Carbon Storage across the Middle Miocene

    Science.gov (United States)

    Babila, T. L.; Sosdian, S. M.; Foster, G. L.; Lear, C. H.

    2017-12-01

    During the Middle Miocene, Earth underwent a profound climate shift from the warmth of the Miocene Climatic Optimum (MCO; 14-17 Ma) to the stable icehouse of today during the Middle Miocene Climate transition (MMCT). Elevated atmospheric carbon dioxide concentrations (pCO2) revealed by boron isotope records (δ11B) link massive volcanic outputs of Columbia River Flood Basalts to the general warmth of MCO. Superimposed on the long-term cooling trend (MMCT) is a gradual pCO2 decline and numerous positive carbon isotope (δ13C) excursions that indicate dynamic variations in the global carbon cycle. Enhanced organic carbon burial via marine productivity, increased silicate weathering and volcanic emission cessation are each invoked to explain the drawdown of pCO2. To better constrain the oceanic role in carbon sequestration over the Middle Miocene detailed records of carbonate chemistry are needed. We present high resolution Boron/Calcium (B/Ca) and δ13C records in planktonic foraminifer T.trilobus spanning 12-17 Ma at ODP 761 (tropical eastern Indian Ocean) to document changes in surface ocean carbonate chemistry. An overall 30% increase in B/Ca ratios is expressed as two stepwise phases occurring at 14.7 and 13 Ma. Cyclic B/Ca variations are coherent with complimentary δ13C records suggesting a tight coupling between ocean carbonate chemistry parameters. Lower resolution B/Ca data at DSDP 588 (Pacific) and ODP 926 (Atlantic) corroborate the trends observed at ODP 761. We employ a paired approach that combines B/Ca (this study) to δ11B (Foster et al., 2012) and an ad hoc calibration to estimate changes in surface ocean dissolved inorganic carbon (DIC). We estimate a substantial decrease in surface ocean DIC spanning the Middle Miocene that culminates with modern day like values. This gradual decline in surface ocean DIC is coeval with existing deep-ocean records which together suggests a whole ocean reduction in carbon storage. We speculate that enhanced weathering

  11. Do storage dynamics in hydropedological units control hydrological connectivity? (Invited)

    Science.gov (United States)

    Tetzlaff, D.; Birkel, C.; Dick, J.; Geris, J.; Soulsby, C.

    2013-12-01

    In many northern landscapes, peat-dominated riparian wetlands often characterise the zone of connection between terrestrial drainage and the river network. In order to understand the relationship between connectivity and stream flow generation in a montane headwater catchment, we examined the storage dynamics and isotopic composition of soil water in major hydropedological units. These formed a classic catena sequence for northern catchments from free-draining podzols on steep upper hillslopes through to peaty gleysols in lower receiving slopes to deeper peats (Histosols) in the riparian zone. The peaty gleys and peats remained saturated throughout the year, whilst the podzols showed distinct wetting and drying cycles. In this climatic region, most precipitation events are less than 10mm in magnitude, storm runoff is mainly generated from the Histosols and Gleysols, with runoff coefficients (RCs) typically horizons of the soils due to mixing with larger volumes of stored water. This damping is accentuated in the deeper soil profile and groundwater. Consequently, the isotopic composition of stream water is also damped, but the strongly reflects that of the near surface waters in the riparian peats. Old 'pre-event' water generally accounts for >80% of flow, even in large events, mainly reflecting the displacement of water stored in the riparian peats and peaty gleys. These riparian areas appear to be the dominant zone where different catchment source waters mix; acting as an 'isostat' that regulates the isotopic composition of stream waters and integrates the Transit Time Distribution (TTD) for the catchment.

  12. Multiply Surface-Functionalized Nanoporous Carbon for Vehicular Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, Peter [Univ. of Missouri, Columbia, MO (United States). Dept. of Physics; Gillespie, Andrew [Univ. of Missouri, Columbia, MO (United States). Dept. of Physics; Stalla, David [Univ. of Missouri, Columbia, MO (United States). Dept. of Physics; Dohnke, Elmar [Univ. of Missouri, Columbia, MO (United States). Dept. of Physics

    2017-02-20

    The purpose of the project “Multiply Surface-Functionalized Nanoporous Carbon for Vehicular Hydrogen Storage” is the development of materials that store hydrogen (H2) by adsorption in quantities and at conditions that outperform current compressed-gas H2 storage systems for electric power generation from hydrogen fuel cells (HFCs). Prominent areas of interest for HFCs are light-duty vehicles (“hydrogen cars”) and replacement of batteries with HFC systems in a wide spectrum of applications, ranging from forklifts to unmanned areal vehicles to portable power sources. State-of-the-art compressed H2 tanks operate at pressures between 350 and 700 bar at ambient temperature and store 3-4 percent of H2 by weight (wt%) and less than 25 grams of H2 per liter (g/L) of tank volume. Thus, the purpose of the project is to engineer adsorbents that achieve storage capacities better than compressed H2 at pressures less than 350 bar. Adsorption holds H2 molecules as a high-density film on the surface of a solid at low pressure, by virtue of attractive surface-gas interactions. At a given pressure, the density of the adsorbed film is the higher the stronger the binding of the molecules to the surface is (high binding energies). Thus, critical for high storage capacities are high surface areas, high binding energies, and low void fractions (high void fractions, such as in interstitial space between adsorbent particles, “waste” storage volume by holding hydrogen as non-adsorbed gas). Coexistence of high surface area and low void fraction makes the ideal adsorbent a nanoporous monolith, with pores wide enough to hold high-density hydrogen films, narrow enough to minimize storage as non-adsorbed gas, and thin walls between pores to minimize the volume occupied by solid instead of hydrogen. A monolith can be machined to fit into a rectangular tank (low pressure, conformable tank), cylindrical tank

  13. Quantifying watershed surface depression storage: determination and application in a hydrologic model

    Science.gov (United States)

    Joseph K. O. Amoah; Devendra M. Amatya; Soronnadi. Nnaji

    2012-01-01

    Hydrologic models often require correct estimates of surface macro-depressional storage to accurately simulate rainfall–runoff processes. Traditionally, depression storage is determined through model calibration or lumped with soil storage components or on an ad hoc basis. This paper investigates a holistic approach for estimating surface depressional storage capacity...

  14. Water, gravity and trees: Relationship of tree-ring widths and total water storage dynamics

    Science.gov (United States)

    Creutzfeldt, B.; Heinrich, I.; Merz, B.; Blume, T.; Güntner, A.

    2012-04-01

    Water stored in the subsurface as groundwater or soil moisture is the main fresh water source not only for drinking water and food production but also for the natural vegetation. In a changing environment water availability becomes a critical issue in many different regions. Long-term observations of the past are needed to improve the understanding of the hydrological system and the prediction of future developments. Tree ring data have repeatedly proved to be valuable sources for reconstructing long-term climate dynamics, e.g. temperature, precipitation and different hydrological variables. In water-limited environments, tree growth is primarily influenced by total water stored in the subsurface and hence, tree-ring records usually contain information about subsurface water storage. The challenge is to retrieve the information on total water storage from tree rings, because a training dataset of water stored in the sub-surface is required for calibration against the tree-ring series. However, measuring water stored in the subsurface is notoriously difficult. We here present high-precision temporal gravimeter measurements which allow for the depth-integrated quantification of total water storage dynamics at the field scale. In this study, we evaluate the relationship of total water storage change and tree ring growth also in the context of the complex interactions of other meteorological forcing factors. A tree-ring chronology was derived from a Norway spruce stand in the Bavarian Forest, Germany. Total water storage dynamics were measured directly by the superconducting gravimeter of the Geodetic Observatory Wettzell for a 9-years period. Time series were extended to 63-years period by a hydrological model using gravity data as the only calibration constrain. Finally, water storage changes were reconstructed based on the relationship between the hydrological model and the tree-ring chronology. Measurement results indicate that tree-ring growth is primarily

  15. Ganglion dynamics and its implications to geologic carbon dioxide storage.

    Science.gov (United States)

    Wang, Yifeng; Bryan, Charles; Dewers, Thomas; Heath, Jason E; Jove-Colon, Carlos

    2013-01-02

    Capillary trapping of a nonwetting fluid phase in the subsurface has been considered as an important mechanism for geologic storage of carbon dioxide (CO(2)). This mechanism can potentially relax stringent requirements for the integrity of cap rocks for CO(2) storage and therefore can significantly enhance storage capacity and security. We here apply ganglion dynamics to understand the capillary trapping of supercritical CO(2) (scCO(2)) under relevant reservoir conditions. We show that, by breaking the injected scCO(2) into small disconnected ganglia, the efficiency of capillary trapping can be greatly enhanced, because the mobility of a ganglion is inversely dependent on its size. Supercritical CO(2) ganglia can be engineered by promoting CO(2)-water interface instability during immiscible displacement, and their size distribution can be controlled by injection mode (e.g., water-alternating-gas) and rate. We also show that a large mobile ganglion can potentially break into smaller ganglia due to CO(2)-brine interface instability during buoyant rise, thus becoming less mobile. The mobility of scCO(2) in the subsurface is therefore self-limited. Vertical structural heterogeneity within a reservoir can inhibit the buoyant rise of scCO(2) ganglia. The dynamics of scCO(2) ganglia described here provides a new perspective for the security and monitoring of subsurface CO(2) storage.

  16. Investigation of longitudinal dynamic in laser electron storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Karnaukhov, I.; Zelinsky, A. E-mail: zelinsky@kipt.kharkov.ua; Telegin, Yu

    2001-09-01

    Longitudinal dynamic of electron beam due to radiation damping and quantum fluctuations in the storage ring with a laser-electron interaction section (Compton scattering) is investigated. This investigation was carried out by numerical simulations using the Monte Carlo method. The dependence of the steady-state energy spread of electron beam due to the Compton back scattering of photons on the electron beam energy and photon flash density were obtained. Simulation findings are compared with the analytical estimations by Z. Huang.

  17. Investigation of longitudinal dynamic in laser electron storage ring

    CERN Document Server

    Karnaukhov, I; Telegin, Yu P

    2001-01-01

    Longitudinal dynamic of electron beam due to radiation damping and quantum fluctuations in the storage ring with a laser-electron interaction section (Compton scattering) is investigated. This investigation was carried out by numerical simulations using the Monte Carlo method. The dependence of the steady-state energy spread of electron beam due to the Compton back scattering of photons on the electron beam energy and photon flash density were obtained. Simulation findings are compared with the analytical estimations by Z. Huang.

  18. Photochemical dynamics of surface oriented molecules

    International Nuclear Information System (INIS)

    Ho, W.

    1992-01-01

    The period 8/01/91-7/31/92 is the first year of a new project titled ''Photochemical Dynamics of Surface Oriented Molecules'', initiated with DOE Support. The main objective of this project is to understand the dynamics of elementary chemical reactions by studying photochemical dynamics of surface-oriented molecules. In addition, the mechanisms of photon-surface interactions need to be elucidated. The strategy is to carry out experiments to measure the translational energy distribution, as a function of the angle from the surface normal, of the photoproducts by time-of-flight (TOF) technique by varying the photon wavelength, intensity, polarization, and pulse duration. By choosing adsorbates with different bonding configuration, the effects of adsorbate orientation on surface photochemical dynamics can be studied

  19. SNF Interim Storage Canister Corrosion and Surface Environment Investigations

    International Nuclear Information System (INIS)

    Bryan, Charles R.; Enos, David G.

    2015-01-01

    This progress report describes work being done at Sandia National Laboratories (SNL) to assess the localized corrosion performance of container/cask materials used in the interim storage of spent nuclear fuel (SNF). Of particular concern is stress corrosion cracking (SCC), by which a through-wall crack could potentially form in a canister outer wall over time intervals that are shorter than possible dry storage times. In order for SCC to occur, three criteria must be met. A corrosive environment must be present on the canister surface, the metal must susceptible to SCC, and sufficient tensile stress to support SCC must be present through the entire thickness of the canister wall. SNL is currently evaluating the potential for each of these criteria to be met.

  20. SNF Interim Storage Canister Corrosion and Surface Environment Investigations

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Charles R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Enos, David G. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    This progress report describes work being done at Sandia National Laboratories (SNL) to assess the localized corrosion performance of container/cask materials used in the interim storage of spent nuclear fuel (SNF). Of particular concern is stress corrosion cracking (SCC), by which a through-wall crack could potentially form in a canister outer wall over time intervals that are shorter than possible dry storage times. In order for SCC to occur, three criteria must be met. A corrosive environment must be present on the canister surface, the metal must susceptible to SCC, and sufficient tensile stress to support SCC must be present through the entire thickness of the canister wall. SNL is currently evaluating the potential for each of these criteria to be met.

  1. Dynamics of Wetting of Ultra Hydrophobic Surfaces

    Science.gov (United States)

    Mohammad Karim, Alireza; Kim, Jeong-Hyun; Rothstein, Jonathan; Kavehpour, Pirouz; Mechanical and Industrial Engineering, University of Massachusetts, Amherst Collaboration

    2013-11-01

    Controlling the surface wettability of hydrophobic and super hydrophobic surfaces has extensive industrial applications ranging from coating, painting and printing technology and waterproof clothing to efficiency increase in power and water plants. This requires enhancing the knowledge about the dynamics of wetting on these hydrophobic surfaces. We have done experimental investigation on the dynamics of wetting on hydrophobic surfaces by looking deeply in to the dependency of the dynamic contact angles both advancing and receding on the velocity of the three-phase boundary (Solid/Liquid/Gas interface) using the Wilhelmy plate method with different ultra-hydrophobic surfaces. Several fluids with different surface tension and viscosity are used to study the effect of physical properties of liquids on the governing laws.

  2. Ab initio lattice dynamics of metal surfaces

    International Nuclear Information System (INIS)

    Heid, R.; Bohnen, K.-P.

    2003-01-01

    Dynamical properties of atoms on surfaces depend sensitively on their bonding environment and thus provide valuable insight into the local geometry and chemical binding at the boundary of a solid. Density-functional theory provides a unified approach to the calculation of structural and dynamical properties from first principles. Its high accuracy and predictive power for lattice dynamical properties of semiconductor surfaces has been demonstrated in a previous article by Fritsch and Schroeder (Phys. Rep. 309 (1999) 209). In this report, we review the state-of-the-art of these ab initio approaches to surface dynamical properties of metal surfaces. We give a brief introduction to the conceptual framework with focus on recent advances in computational procedures for the ab initio linear-response approach, which have been a prerequisite for an efficient treatment of surface dynamics of noble and transition metals. The discussed applications to clean and adsorbate-covered surfaces demonstrate the high accuracy and reliability of this approach in predicting detailed microscopic properties of the phonon dynamics for a wide range of metallic surfaces

  3. Causal Dynamics of Discrete Surfaces

    Directory of Open Access Journals (Sweden)

    Pablo Arrighi

    2014-03-01

    Full Text Available We formalize the intuitive idea of a labelled discrete surface which evolves in time, subject to two natural constraints: the evolution does not propagate information too fast; and it acts everywhere the same.

  4. Characterizing heterogeneous dynamics at hydrated electrode surfaces

    Science.gov (United States)

    Willard, Adam P.; Limmer, David T.; Madden, Paul A.; Chandler, David

    2013-05-01

    In models of Pt 111 and Pt 100 surfaces in water, motions of molecules in the first hydration layer are spatially and temporally correlated. To interpret these collective motions, we apply quantitative measures of dynamic heterogeneity that are standard tools for considering glassy systems. Specifically, we carry out an analysis in terms of mobility fields and distributions of persistence times and exchange times. In so doing, we show that dynamics in these systems is facilitated by transient disorder in frustrated two-dimensional hydrogen bonding networks. The frustration is the result of unfavorable geometry imposed by strong metal-water bonding. The geometry depends upon the structure of the underlying metal surface. Dynamic heterogeneity of water on the Pt 111 surface is therefore qualitatively different than that for water on the Pt 100 surface. In both cases, statistics of this ad-layer dynamic heterogeneity responds asymmetrically to applied voltage.

  5. Characterizing heterogeneous dynamics at hydrated electrode surfaces.

    Science.gov (United States)

    Willard, Adam P; Limmer, David T; Madden, Paul A; Chandler, David

    2013-05-14

    In models of Pt 111 and Pt 100 surfaces in water, motions of molecules in the first hydration layer are spatially and temporally correlated. To interpret these collective motions, we apply quantitative measures of dynamic heterogeneity that are standard tools for considering glassy systems. Specifically, we carry out an analysis in terms of mobility fields and distributions of persistence times and exchange times. In so doing, we show that dynamics in these systems is facilitated by transient disorder in frustrated two-dimensional hydrogen bonding networks. The frustration is the result of unfavorable geometry imposed by strong metal-water bonding. The geometry depends upon the structure of the underlying metal surface. Dynamic heterogeneity of water on the Pt 111 surface is therefore qualitatively different than that for water on the Pt 100 surface. In both cases, statistics of this ad-layer dynamic heterogeneity responds asymmetrically to applied voltage.

  6. The role of storage dynamics in annual wheat prices

    Science.gov (United States)

    Schewe, Jacob; Otto, Christian; Frieler, Katja

    2017-05-01

    Identifying the drivers of global crop price fluctuations is essential for estimating the risks of unexpected weather-induced production shortfalls and for designing optimal response measures. Here we show that with a consistent representation of storage dynamics, a simple supply-demand model can explain most of the observed variations in wheat prices over the last 40 yr solely based on time series of annual production and long term demand trends. Even the most recent price peaks in 2007/08 and 2010/11 can be explained by additionally accounting for documented changes in countries’ trade policies and storage strategies, without the need for external drivers such as oil prices or speculation across different commodity or stock markets. This underlines the critical sensitivity of global prices to fluctuations in production. The consistent inclusion of storage into a dynamic supply-demand model closes an important gap when it comes to exploring potential responses to future crop yield variability under climate and land-use change.

  7. DYNAMIC ABC STORAGE POLICY IN ERRATIC DEMAND ENVIRONMENTS

    Directory of Open Access Journals (Sweden)

    Benjamin Pierre

    2003-01-01

    Full Text Available The paper describes a dynamic variant of the traditional ABC storage policy. The variant is to be used in manual order picking warehouses where SKUs experience a rather unstable demand. Its objective is to reduce the order picking time. It mainly consists in shifting items between the storage areas A, B and C according to the way their daily number of order lines changes. A few case studies based on computer simulations have shown that this variant can yield interesting time savings if its parameters are chosen with care. One of those case studies is presented in this paper. Because of the pioneering nature of this variant, some ideas for further research are also sketched.

  8. Thermal energy storage for a space solar dynamic power system

    Science.gov (United States)

    Faget, N. M.; Fraser, W. M., Jr.; Simon, W. E.

    1985-01-01

    In the past, NASA has employed solar photovoltaic devices for long-duration missions. Thus, the Skylab system has operated with a silicon photovoltaic array and a nickel-cadmium electrochemical system energy storage system. Difficulties regarding the employment of such a system for the larger power requirements of the Space Station are related to a low orbit system efficiency and the large weight of the battery. For this reason the employment of a solar dynamic power system (SDPS) has been considered. The primary components of an SDPS include a concentrating mirror, a heat receiver, a thermal energy storage (TES) system, a thermodynamic heat engine, an alternator, and a heat rejection system. The heat-engine types under consideration are a Brayton cycle engine, an organic Rankine cycle engine, and a free-piston/linear-alternator Stirling cycle engine. Attention is given to a system description, TES integration concepts, and a TES technology assessment.

  9. Phase change energy storage for solar dynamic power systems

    Science.gov (United States)

    Chiaramonte, F. P.; Taylor, J. D.

    1992-01-01

    This paper presents the results of a transient computer simulation that was developed to study phase change energy storage techniques for Space Station Freedom (SSF) solar dynamic (SD) power systems. Such SD systems may be used in future growth SSF configurations. Two solar dynamic options are considered in this paper: Brayton and Rankine. Model elements consist of a single node receiver and concentrator, and takes into account overall heat engine efficiency and power distribution characteristics. The simulation not only computes the energy stored in the receiver phase change material (PCM), but also the amount of the PCM required for various combinations of load demands and power system mission constraints. For a solar dynamic power system in low earth orbit, the amount of stored PCM energy is calculated by balancing the solar energy input and the energy consumed by the loads corrected by an overall system efficiency. The model assumes an average 75 kW SD power system load profile which is connected to user loads via dedicated power distribution channels. The model then calculates the stored energy in the receiver and subsequently estimates the quantity of PCM necessary to meet peaking and contingency requirements. The model can also be used to conduct trade studies on the performance of SD power systems using different storage materials.

  10. Surface-confined electroactive molecules for multistate charge storage information.

    Science.gov (United States)

    Mas-Torrent, M; Rovira, C; Veciana, J

    2013-01-18

    Bi-stable molecular systems with potential for applications in binary memory devices are raising great interest for device miniaturization. Particular appealing are those systems that operate with electrical inputs since they are compatible with existing electronic technologies. The processing of higher memory densities in these devices could be accomplished by increasing the number of memory states in each cell, although this strategy has not been much explored yet. Here we highlight the recent advances devoted to the fabrication of charge-storage molecular surface-confined devices exhibiting multiple states. Mainly, this goal has been realized immobilizing a variety (or a combination) of electroactive molecules on a surface, although alternative approaches employing non-electroactive systems have also been described. Undoubtedly, the use of molecules with chemically tunable properties and nanoscale dimensions are raising great hopes for the devices of the future in which molecules can bring new perspectives such as multistability.

  11. Dynamic Factor Models for the Volatility Surface

    DEFF Research Database (Denmark)

    van der Wel, Michel; Ozturk, Sait R.; Dijk, Dick van

    The implied volatility surface is the collection of volatilities implied by option contracts for different strike prices and time-to-maturity. We study factor models to capture the dynamics of this three-dimensional implied volatility surface. Three model types are considered to examine desirable...

  12. Monitoring groundwater storage changes in the highly dynamic Bengal Basin: validation of GRACE measurements

    Science.gov (United States)

    Shamsudduha, M.; Taylor, R. G.; Longuevergne, L.

    2011-12-01

    Monitoring of spatio-temporal changes in terrestrial water storage (ΔTWS) provides valuable information regarding the basin-scale dynamics of hydrological systems. Recent satellite measurements of the ΔTWS under the Gravity Recovery and Climate Experiment (GRACE) enable the derivation of groundwater storage changes (ΔGWS) where in situ data are limited. In the well monitored and highly-dynamic Bengal Basin of Bangladesh, we test the ability of GRACE measurements to trace the seasonality and trend in groundwater storage associated with intensive groundwater abstraction for dry-season irrigation and wet-season (monsoonal) recharge. Two different GRACE products (CSR and GRGS) and data processing methods (gridded and spherical harmonics) are also compared. Results show that GRACE derived estimates of recent (2003 to 2007) ΔGWS correlate well (r=0.77 to 0.93, p-value CSR for these estimates. ΔGWS accounts for 44% of the total variation in ΔTWS in the Bengal Basin. Changes in surface water storage (ΔSWS) estimated from a network of 298 river gauging stations and soil moisture storage (ΔSMS) derived from Land Surface Models explain 22% and 33% of ΔTWS respectively. Groundwater depletion estimated from borehole hydrographs (-0.52±0.30 km3/yr) is within the range of satellite-derived estimates (-0.44 to -2.04 km3/yr) that result from uncertainty associated with ΔSMS (CLM, NOAH, VIC) and GRACE data processing techniques. Recent (2003 to 2007) estimates of groundwater depletion are substantially greater than the long-term (1985 to 2007) mean (-0.21±0.03 km3/yr) and are explained primarily by substantial increases in groundwater abstraction for the dry-season irrigation and drinking water supplies over the last two decades.

  13. Atomic probes of surface structure and dynamics

    International Nuclear Information System (INIS)

    Heller, E.J.; Jonsson, H.

    1992-01-01

    Progress for the period Sept. 15, 1992 to Sept. 14, 1993 is discussed. Semiclassical methods that will allow much faster and more accurate three-dimensional atom--surface scattering calculations, both elastic and inelastic, are being developed. The scattering of He atoms from buckyballs is being investigated as a test problem. Somewhat more detail is given on studies of He atom scattering from defective Pt surfaces. Molecular dynamics simulations of He + and Ar + ion sputtering of Pt surfaces are also being done. He atom scattering from Xe overlayers on metal surfaces and the thermalized dissociation of H 2 on Cu(110) are being studied. (R.W.R.) 64 refs

  14. Functional dynamics of cell surface membrane proteins.

    Science.gov (United States)

    Nishida, Noritaka; Osawa, Masanori; Takeuchi, Koh; Imai, Shunsuke; Stampoulis, Pavlos; Kofuku, Yutaka; Ueda, Takumi; Shimada, Ichio

    2014-04-01

    Cell surface receptors are integral membrane proteins that receive external stimuli, and transmit signals across plasma membranes. In the conventional view of receptor activation, ligand binding to the extracellular side of the receptor induces conformational changes, which convert the structure of the receptor into an active conformation. However, recent NMR studies of cell surface membrane proteins have revealed that their structures are more dynamic than previously envisioned, and they fluctuate between multiple conformations in an equilibrium on various timescales. In addition, NMR analyses, along with biochemical and cell biological experiments indicated that such dynamical properties are critical for the proper functions of the receptors. In this review, we will describe several NMR studies that revealed direct linkage between the structural dynamics and the functions of the cell surface membrane proteins, such as G-protein coupled receptors (GPCRs), ion channels, membrane transporters, and cell adhesion molecules. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Surface-Assisted Dynamic Search Processes.

    Science.gov (United States)

    Shin, Jaeoh; Kolomeisky, Anatoly B

    2018-03-01

    Many chemical and biological systems exhibit intermittent search phenomena when participating particles alternate between dynamic regimes with different dimensionalities. Here we investigate theoretically a dynamic search process of finding a small target on a two-dimensional surface starting from a bulk solution, which is an example of such an intermittent search process. Both continuum and discrete-state stochastic descriptions are developed. It is found that depending on the scanning length λ, which describes the area visited by the reacting molecule during one search cycle, the system can exhibit three different search regimes: (i) For small λ values, the reactant finds the target mostly via three-dimensional bulk diffusion; (ii) for large λ values, the reactant molecule associates to the target mostly via surface diffusion; and (iii) for intermediate λ values, the reactant reaches the target via a combination of three-dimensional and two-dimensional search cycles. Our analysis also shows that the mean search times have different scalings as a function of the size of the surface segment depending on the nature of the dynamic search regime. Search dynamics are also sensitive to the position of the target for large scanning lengths. In addition, it is argued that the continuum description underestimates mean search times and does not always correctly describe the most optimal conditions for the surface-assisted dynamic processes. The importance of our findings for real natural systems is discussed.

  16. Surface dynamics of micellar diblock copolymer films

    Science.gov (United States)

    Song, Sanghoon; Cha, Wonsuk; Kim, Hyunjung; Jiang, Zhang; Narayanan, Suresh

    2011-03-01

    We studied the structure and surface dynamics of poly(styrene)-b-poly(dimethylsiloxane) (PS-b-PDMS) diblock copolymer films with micellar PDMS surrounded by PS shells. By `in-situ' high resolution synchrotron x-ray reflectivity and diffuse scattering, we obtained exact thickness, electron density and surface tension. A segregation layer near the top surface was appeared with increasing temperature Surface dynamics were measured as a function of film thickness and temperature by x-ray photon correlation spectroscopy. The best fit to relaxation time constants as a function of in-plane wavevectors were analyzed with a theory based on capillary waves with hydrodynamics with bilayer model Finally the viscosities for the top segregated layer as well as for the bottom layer are obtained at given temperatures This work was supported by National Research Foundation of Korea (R15-2008-006-01001-0), Seoul Research and Business Development Program (10816), and Sogang University Research Grant (2010).

  17. Surface water storage capacity of twenty tree species in Davis, California

    Science.gov (United States)

    Qingfu Xiao; E. Gregory. McPherson

    2016-01-01

    Urban forestry is an important green infrastructure strategy because healthy trees can intercept rainfall, reducing stormwater runoff and pollutant loading. Surface saturation storage capacity, defined as the thin film of water that must wet tree surfaces before flow begins, is the most important variable influencing rainfall interception processes. Surface storage...

  18. The dynamic storage and restart facilities in MABEL-2

    International Nuclear Information System (INIS)

    Nye, M.T.S.

    1983-12-01

    MABEL-2 is a FORTRAN program for calculating clad ballooning in a PWR during a LOCA. Originally written with fixed array storage, the use of the code has been extended by including dynamic storage. The lengths of the arrays in the program are set at execution time, varying from run to run. This allows much greater freedom in the choice of mesh and the size of case run. The use of computer memory is also more efficient. In addition a restart facility has been included which allows the user to break off and restart execution of the program (once or many times) during a transient. By using this facility much longer calculations can be run. Should an error in either input data or program become apparent late in a transient, the case need only be re-run from the last dump because some input data can be altered at restart. The use of these new facilities and the coding changes are described. (author)

  19. Dynamic visual noise interferes with storage in visual working memory.

    Science.gov (United States)

    Dean, Graham M; Dewhurst, Stephen A; Whittaker, Annalise

    2008-01-01

    Several studies have demonstrated that dynamic visual noise (DVN) does not interfere with memory for random matrices. This has led to suggestions that (a) visual working memory is distinct from imagery, and (b) visual working memory is not a gateway between sensory input and long-term storage. A comparison of the interference effects of DVN with memory for matrices and colored textures shows that DVN can interfere with visual working memory, probably at a level of visual detail not easily supported by long-term memory structures or the recoding of the visual pattern elements. The results support a gateway model of visuospatial working memory and raise questions about the most appropriate ways to measure and model the different levels of representation of information that can be held in visual working memory.

  20. Dynamic Defrosting on Scalable Superhydrophobic Surfaces

    International Nuclear Information System (INIS)

    Murphy, Kevin R.; McClintic, William T.; Lester, Kevin C.; Collier, C. Patrick; Boreyko, Jonathan B.

    2017-01-01

    Recent studies have shown that frost can grow in a suspended Cassie state on nanostructured superhydrophobic surfaces. During defrosting, the melting sheet of Cassie frost spontaneously dewets into quasi-spherical slush droplets that are highly mobile. Promoting Cassie frost would therefore seem advantageous from a defrosting standpoint; however, nobody has systematically compared the efficiency of defrosting Cassie ice versus defrosting conventional surfaces. Here, we characterize the defrosting of an aluminum plate, one-half of which exhibits a superhydrophobic nanostructure while the other half is smooth and hydrophobic. For thick frost sheets (>1 mm), the superhydrophobic surface was able to dynamically shed the meltwater, even at very low tilt angles. In contrast, the hydrophobic surface was unable to shed any appreciable meltwater even at a 90° tilt angle. For thin frost layers (≲1 mm), not even the superhydrophobic surface could mobilize the meltwater. We attribute this to the large apparent contact angle of the meltwater, which for small amounts of frost serves to minimize coalescence events and prevent droplets from approaching the capillary length. Finally, we demonstrate a new mode of dynamic defrosting using an upside-down surface orientation, where the melting frost was able to uniformly detach from the superhydrophobic side and subsequently pull the frost from the hydrophobic side in a chain reaction. Treating surfaces to enable Cassie frost is therefore very desirable for enabling rapid and low-energy thermal defrosting, but only for frost sheets that are sufficiently thick.

  1. Channel Storage change: a new remote sensed surface water measurement

    Science.gov (United States)

    Coss, S. P.; Durand, M. T.; Yi, Y.; Guo, Q.; Shum, C. K.; Allen, G. H.; Pavelsky, T.

    2017-12-01

    Here we present river channel storage change (CSC) measurements for 17 major world rivers from 2002-2016. We combined interpolated daily 1 km resolution Global River Radar Altimeter Time Series (GRRATS) river surface elevation data with static widths from the global river Global River Widths from Landsat (GRWL) dataset, to generate preliminary channel storage measurements. CSC is a previously unmeasured component of the terrestrial water balance It is a fundamental Earth science quantity with global bearing on floodplains, ecology, and geochemistry. CSC calculations require only remote sensed data, making them an ideal tool for studying remote regions where hydrological data is not easily accessible. CSC is uniquely suited to determine the role of hydrologic and hydraulic controls in basins with strong seasonal cycles (freeze-up and break-up). The cumulative CSC anomaly can impart spatial details that discharge measurements cannot. With this new measurement, we may be able to determine critical hydrological and hydraulic controls on rapidly changing systems like Arctic rivers. Results for Mississippi River indicate that peak CSC anomaly was the highest in 2011 (12.6 km3) and minimum CSC anomaly was in 2012 (-12.2 km3). Peak CSC has most frequently occurs in May (5 years), but has come as late in the year as July, and as early as January. Results for the Yukon River indicate that peak CSC anomaly was the highest in 2013 (13.9 km3) and minimum CSC anomaly was in 2010 (-14.2 km3). Peak CSC has most frequently come in early to mid-June (4-18), but has occurred in May (19-31) four years in the study period (three of the last 6 years) and once on April 30th.

  2. Dynamic air layer on textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev

    2013-09-03

    We provide an experimental demonstration that a novel macroscopic, dynamic continuous air layer or plastron can be sustained indefinitely on textured superhydrophobic surfaces in air-supersaturated water by a natural gas influx mechanism. This type of plastron is an intermediate state between Leidenfrost vapor layers on superheated surfaces and the equilibrium Cassie-Baxter wetting state on textured superhydrophobic surfaces. We show that such a plastron can be sustained on the surface of a centimeter-sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux into the plastron and identification of the air transport model of the plastron growth. Both the observed growth dynamics of such plastrons and millimeter-sized air bubbles seeded on the hydrophilic surface under identical air-supersaturated solution conditions are consistent with the predictions of a well-mixed gas transport model. © 2013 American Chemical Society.

  3. Hydrodynamic Characterization of a Surface Storage Zone in a Natural Stream

    Science.gov (United States)

    Sandoval Ulloa, J. C.; Escauriaza, C. R.; Mignot, E.; Mao, L.

    2015-12-01

    Flow developed in surface storage zones in rivers is very important for many physical and biogeochemical processes. These regions are characterized by low velocities compared to the flow in the main channel and long residence times that favor the deposition of contaminants, nutrient uptake and interactions with reactive sediments. The dynamics of the turbulent flows in these zones is very complex, typically characterized by a shear layer that induces a recirculating area, with multiple large-scale coherent structures of different temporal and spatial scales. In this work we present the methodology and analysis of measurements in a natural surface storage zone. We report detailed information of a field campaign carried out in the Lluta River, located in northern Chile in the high altitude Andean environment known as the Altiplano (~4,000 masl). The area of study has great interest for the river ecosystem, since the water has high concentration levels of arsenic and other metals. The Lluta River is also a water source for many agricultural communities and urban centers located in the lower parts of the watershed. Field information obtained was: detailed topography, 3D velocity components in several points, and sediment arsenic concentration in the main channel and in the recirculating region of the natural surface storage zone. Topography was obtained through DGPS and digital image processing. The 3D velocity field was measured with an acoustic Doppler velocimeter (ADV) and surface velocity data was obtained through the LSPIV technique. Arsenic concentration was obtained by sediment sampling analysis. With this data we analyze the flow topology and characteristics features of the velocity, which constitute the controlling mechanisms of contaminant transport in the field. In addition, we contrast with preliminary results of a three-dimensional (3D) numerical simulation, to determine the influence of different parameters on the transport and mixing processes in natural

  4. CFD simulations on the dynamics of liquid sloshing and its control in a storage tank for spent fuel applications

    International Nuclear Information System (INIS)

    Sanapala, V.S.; Velusamy, K.; Patnaik, B.S.V.

    2016-01-01

    Highlights: • Dynamics of sloshing in partially filled spent fuel storage tanks is numerically simulated. • Two type of baffle plates were examined towards the control of slosh suppression. • An optimum baffles configuration was obtained, after carrying out systematic investigations. • This vertical baffle design was effective, when tested for a seismic excitation (El centro). - Abstract: Spent nuclear liquid waste is often kept in partially filled storage tanks. When such storage tanks are subjected to wind and/or earthquake induced excitations, this could lead to detrimental conditions. Therefore, storage tank designers should ensure safe design margins and develop methodologies to overcome a wide range of possible scenarios. In the present study, systematic numerical simulations are carried out to investigate the sloshing dynamics of liquid in a storage tank, subjected to seismic excitation. As a precursor, the influence of resonant harmonic excitation on the free surface displacement, pressure distribution, slosh forces etc. is studied. To suppress the free surface fluctuations and the associated slosh force, two types of baffles viz., ring and vertical baffle are examined. Based on the response to an imposed harmonic excitation, the vertical baffle plate in the middle of the tank, was found to be effective and its dimensions are systematically optimized. This baffle geometry was tested for a well known seismic excitation (El Centro) and it was observed to effectively suppress free surface fluctuations and the slosh forces.

  5. Dynamic Non-Hierarchical File Systems for Exascale Storage

    Energy Technology Data Exchange (ETDEWEB)

    Long, Darrell E. [Univ. of California, Santa Cruz, CA (United States); Miller, Ethan L [Univ. of California, Santa Cruz, CA (United States)

    2015-02-24

    This constitutes the final report for “Dynamic Non-Hierarchical File Systems for Exascale Storage”. The ultimate goal of this project was to improve data management in scientific computing and high-end computing (HEC) applications, and to achieve this goal we proposed: to develop the first, HEC-targeted, file system featuring rich metadata and provenance collection, extreme scalability, and future storage hardware integration as core design goals, and to evaluate and develop a flexible non-hierarchical file system interface suitable for providing more powerful and intuitive data management interfaces to HEC and scientific computing users. Data management is swiftly becoming a serious problem in the scientific community – while copious amounts of data are good for obtaining results, finding the right data is often daunting and sometimes impossible. Scientists participating in a Department of Energy workshop noted that most of their time was spent “...finding, processing, organizing, and moving data and it’s going to get much worse”. Scientists should not be forced to become data mining experts in order to retrieve the data they want, nor should they be expected to remember the naming convention they used several years ago for a set of experiments they now wish to revisit. Ideally, locating the data you need would be as easy as browsing the web. Unfortunately, existing data management approaches are usually based on hierarchical naming, a 40 year-old technology designed to manage thousands of files, not exabytes of data. Today’s systems do not take advantage of the rich array of metadata that current high-end computing (HEC) file systems can gather, including content-based metadata and provenance1 information. As a result, current metadata search approaches are typically ad hoc and often work by providing a parallel management system to the “main” file system, as is done in Linux (the locate utility), personal computers, and enterprise search

  6. Heat in the Barents Sea: transport, storage, and surface fluxes

    Directory of Open Access Journals (Sweden)

    L. H. Smedsrud

    2010-02-01

    Full Text Available A column model is set up for the Barents Sea to explore sensitivity of surface fluxes and heat storage from varying ocean heat transport. Mean monthly ocean transport and atmospheric forcing are synthesised and force the simulations. Results show that by using updated ocean transports of heat and freshwater the vertical mean hydrographic seasonal cycle can be reproduced fairly well.

    Our results indicate that the ~70 TW of heat transported to the Barents Sea by ocean currents is lost in the southern Barents Sea as latent, sensible, and long wave radiation, each contributing 23–39 TW to the total heat loss. Solar radiation adds 26 TW in the south, as there is no significant ice production.

    The northern Barents Sea receives little ocean heat transport. This leads to a mixed layer at the freezing point during winter and significant ice production. There is little net surface heat loss annually in the north. The balance is achieved by a heat loss through long wave radiation all year, removing most of the summer solar heating.

    During the last decade the Barents Sea has experienced an atmospheric warming and an increased ocean heat transport. The Barents Sea responds to such large changes by adjusting temperature and heat loss. Decreasing the ocean heat transport below 50 TW starts a transition towards Arctic conditions. The heat loss in the Barents Sea depend on the effective area for cooling, and an increased heat transport leads to a spreading of warm water further north.

  7. Application of dielectric surface barrier discharge for food storage

    Directory of Open Access Journals (Sweden)

    Yassine BELLEBNA

    2015-12-01

    Full Text Available Ozone (O3 is a powerful oxidizer and has much higher disinfection potential than chlorine and other disinfectants. Ozone finds its application mainly in water treatment and air purification Dielectric barrier discharge (DBD method has proved to be the best method to produce ozone. Dried air or oxygen is forced to pass through a 1-2 mm gap. The aim of this study was to show that disinfection system using ozone generated by dielectric barrier discharge (DBD is an effective alternative to be used in food industry and ensures a safe quality of air for optimum preservation of fruits and vegetables. The DBDs are specific kind of discharges because one (or sometimes both electrodes is covered by a dielectric material, thereby preventing the discharge to move towards electrical breakdown. A succession of microdischarges occurs rapidly; their "lifetime" is in the range of a few nanoseconds. One of their most important applications is the production of ozone for air treatment, used mainly in the area of food industry, for extending the storage life of foods. After the achievement of a surface DBD reactor of cylindrical shape and its electrical characterization, it was then used as an ozone generator for air disinfection. Obtained results have shown that this reactor used as an ozone generator is effective for disinfection of air by removing viruses, bacteria and pathogens, causing the slowdown of the ripening process of fruits and vegetables.

  8. Retrievable surface storage facility conceptual system design description

    Energy Technology Data Exchange (ETDEWEB)

    1977-03-01

    The studies evaluated several potentially attractive methods for processing and retrievably storing high-level radioactive waste after delivery to the Federal repository. These studies indicated that several systems could be engineered to safely store the waste, but that the simplest and most attractive concept from a technical standpoint would be to store the waste in a sealed stainless steel canister enclosed in a 2 in. thick carbon steel cask which in turn would be inserted into a reinforced concrete gamma-neutron shield, which would also provide the necessary air-cooling through an air annulus between the cask and the shield. This concept best satisfies the requirements for safety, long-term exposure to natural phenomena, low capital and operating costs, retrievability, amenability to incremental development, and acceptably small environmental impact. This document assumes that the reference site would be on ERDA's Hanford reservation. This document is a Conceptual System Design Description of the facilities which could satisfy all of the functional requirements within the established basic design criteria. The Retrievable Surface Storage Facility (RSSF) is planned with the capacity to process and store the waste received in either a calcine or glass/ceramic form. The RSSF planning is based on a modular development program in which the modular increments are constructed at rates matching projected waste receipts.

  9. Retrievable surface storage facility conceptual system design description

    International Nuclear Information System (INIS)

    1977-03-01

    The studies evaluated several potentially attractive methods for processing and retrievably storing high-level radioactive waste after delivery to the Federal repository. These studies indicated that several systems could be engineered to safely store the waste, but that the simplest and most attractive concept from a technical standpoint would be to store the waste in a sealed stainless steel canister enclosed in a 2 in. thick carbon steel cask which in turn would be inserted into a reinforced concrete gamma-neutron shield, which would also provide the necessary air-cooling through an air annulus between the cask and the shield. This concept best satisfies the requirements for safety, long-term exposure to natural phenomena, low capital and operating costs, retrievability, amenability to incremental development, and acceptably small environmental impact. This document assumes that the reference site would be on ERDA's Hanford reservation. This document is a Conceptual System Design Description of the facilities which could satisfy all of the functional requirements within the established basic design criteria. The Retrievable Surface Storage Facility (RSSF) is planned with the capacity to process and store the waste received in either a calcine or glass/ceramic form. The RSSF planning is based on a modular development program in which the modular increments are constructed at rates matching projected waste receipts

  10. Dynamic analysis of a pumped-storage hydropower plant with random power load

    Science.gov (United States)

    Zhang, Hao; Chen, Diyi; Xu, Beibei; Patelli, Edoardo; Tolo, Silvia

    2018-02-01

    This paper analyzes the dynamic response of a pumped-storage hydropower plant in generating mode. Considering the elastic water column effects in the penstock, a linearized reduced order dynamic model of the pumped-storage hydropower plant is used in this paper. As the power load is always random, a set of random generator electric power output is introduced to research the dynamic behaviors of the pumped-storage hydropower plant. Then, the influences of the PI gains on the dynamic characteristics of the pumped-storage hydropower plant with the random power load are analyzed. In addition, the effects of initial power load and PI parameters on the stability of the pumped-storage hydropower plant are studied in depth. All of the above results will provide theoretical guidance for the study and analysis of the pumped-storage hydropower plant.

  11. Dynamically triangulated surfaces - some analytical results

    International Nuclear Information System (INIS)

    Kostov, I.K.

    1987-01-01

    We give a brief review of the analytical results concerning the model of dynamically triangulated surfaces. We will discuss the possible types of critical behaviour (depending on the dimension D of the embedding space) and the exact solutions obtained for D=0 and D=-2. The latter are important as a check of the Monte Carlo simulations applyed to study the model in more physical dimensions. They give also some general insight of its critical properties

  12. Dynamic bioactive stimuli-responsive polymeric surfaces

    Science.gov (United States)

    Pearson, Heather Marie

    This dissertation focuses on the design, synthesis, and development of antimicrobial and anticoagulant surfaces of polyethylene (PE), polypropylene (PP), and poly(tetrafluoroethylene) (PTFE) polymers. Aliphatic polymeric surfaces of PE and PP polymers functionalized using click chemistry reactions by the attachment of --COOH groups via microwave plasma reactions followed by functionalization with alkyne moieties. Azide containing ampicillin (AMP) was synthesized and subsequently clicked into the alkyne prepared PE and PP surfaces. Compared to non-functionalized PP and PE surfaces, the AMP clicked surfaces exhibited substantially enhanced antimicrobial activity against Staphylococcus aureus bacteria. To expand the biocompatibility of polymeric surface anticoagulant attributes, PE and PTFE surfaces were functionalized with pH-responsive poly(2-vinyl pyridine) (P2VP) and poly(acrylic acid) (PAA) polyelectrolyte tethers terminated with NH2 and COOH groups. The goal of these studies was to develop switchable stimuli-responsive polymeric surfaces that interact with biological environments and display simultaneous antimicrobial and anticoagulant properties. Antimicrobial AMP was covalently attached to --COOH terminal ends of protected PAA, while anticoagulant heparin (HEP) was attached to terminal --NH2 groups of P2VP. When pH 5.5, they collapse while the PAA segments extend. Such surfaces, when exposed to Staphylococcus aureus, inhibit bacterial growth due to the presence of AMP, as well as are effective anticoagulants due to the presence of covalently attached HEP. Comparison of these "dynamic" pH responsive surfaces with "static" surfaces terminated with AMP entities show significant enhancement of longevity and surface activity against microbial film formation. The last portion of this dissertation focuses on the covalent attachment of living T1 and Φ11 bacteriophages (phages) on PE and PTFE surface. This was accomplished by carbodiimide coupling between --COOH

  13. Dynamic contact angle cycling homogenizes heterogeneous surfaces.

    Science.gov (United States)

    Belibel, R; Barbaud, C; Mora, L

    2016-12-01

    In order to reduce restenosis, the necessity to develop the appropriate coating material of metallic stent is a challenge for biomedicine and scientific research over the past decade. Therefore, biodegradable copolymers of poly((R,S)-3,3 dimethylmalic acid) (PDMMLA) were prepared in order to develop a new coating exhibiting different custom groups in its side chain and being able to carry a drug. This material will be in direct contact with cells and blood. It consists of carboxylic acid and hexylic groups used for hydrophilic and hydrophobic character, respectively. The study of this material wettability and dynamic surface properties is of importance due to the influence of the chemistry and the potential motility of these chemical groups on cell adhesion and polymer kinetic hydrolysis. Cassie theory was used for the theoretical correction of contact angles of these chemical heterogeneous surfaces coatings. Dynamic Surface Analysis was used as practical homogenizer of chemical heterogeneous surfaces by cycling during many cycles in water. In this work, we confirmed that, unlike receding contact angle, advancing contact angle is influenced by the difference of only 10% of acidic groups (%A) in side-chain of polymers. It linearly decreases with increasing acidity percentage. Hysteresis (H) is also a sensitive parameter which is discussed in this paper. Finally, we conclude that cycling provides real information, thus avoiding theoretical Cassie correction. H(10)is the most sensible parameter to %A. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Modeling Lake Storage Dynamics to support Arctic Boreal Vulnerability Experiment (ABoVE)

    Science.gov (United States)

    Vimal, S.; Lettenmaier, D. P.; Smith, L. C.; Smith, S.; Bowling, L. C.; Pavelsky, T.

    2017-12-01

    The Arctic and Boreal Zone (ABZ) of Canada and Alaska includes vast areas of permafrost, lakes, and wetlands. Permafrost thawing in this area is expected to increase due to the projected rise of temperature caused by climate change. Over the long term, this may reduce overall surface water area, but in the near-term, the opposite is being observed, with rising paludification (lake/wetland expansion). One element of NASA's ABoVE field experiment is observations of lake and wetland extent and surface elevations using NASA's AirSWOT airborne interferometric radar, accompanied by a high-resolution camera. One use of the WSE retrievals will be to constrain model estimates of lake storage dynamics. Here, we compare predictions using the lake dynamics algorithm within the Variable Infiltration Capacity (VIC) land surface scheme. The VIC lake algorithm includes representation of sub-grid topography, where the depth and area of seasonally-flooded areas are modeled as a function of topographic wetness index, basin area, and slope. The topography data used is from a new global digital elevation model, MERIT-DEM. We initially set up VIC at sites with varying permafrost conditions (i.e., no permafrost, discontinuous, continuous) in Saskatoon and Yellowknife, Canada, and Toolik Lake, Alaska. We constrained the uncalibrated model with the WSE at the time of the first ABoVE flight, and quantified the model's ability to predict WSE and ΔWSE during the time of the second flight. Finally, we evaluated the sensitivity of the VIC-lakes model and compared the three permafrost conditions. Our results quantify the sensitivity of surface water to permafrost state across the target sites. Furthermore, our evaluation of the lake modeling framework contributes to the modeling and mapping framework for lake and reservoir storage change evaluation globally as part of the SWOT mission, planned for launch in 2021.

  15. Effect of surface modification and hybridization on dynamic ...

    Indian Academy of Sciences (India)

    Storage and loss modulus values increased after treatments with simultaneous decrease in tan values. Roystonea regia and glass fibres were used together with varying proportions as reinforcement in epoxy matrix to study the hybridization effect on dynamic mechanical properties. Storage and loss modulus values ...

  16. Influence of surface oxidation on ion dynamics and capacitance in porous and nonporous carbon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Dyatkin, Boris [Drexel Univ., Philadelphia, PA (United States); Zhang, Yu [Vanderbilt Univ., Nashville, TN (United States); Mamontov, Eugene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kolesnikov, Alexander I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cheng, Yongqiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Meyer, III, Harry M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cummings, Peter T. [Vanderbilt Univ., Nashville, TN (United States); Gogotsi, Yury G. [Drexel Univ., Philadelphia, PA (United States)

    2016-04-07

    Here, we investigate the influence of surface chemistry and ion confinement on capacitance and electrosorption dynamics of room-temperature ionic liquids (RTILs) in supercapacitors. Using air oxidation and vacuum annealing, we produced defunctionalized and oxygen-rich surfaces of carbide-derived carbons (CDCs) and graphene nanoplatelets (GNPs). While oxidized surfaces of porous CDCs improve capacitance and rate handling abilities of ions, defunctionalized nonporous GNPs improve charge storage densities on planar electrodes. Quasi-elastic neutron scattering (QENS) and inelastic neutron scattering (INS) probed the structure, dynamics, and orientation of RTIL ions confined in divergently functionalized pores. Oxidized, ionophilic surfaces draw ions closer to pore surfaces and enhance potential-driven ion transport during electrosorption. Molecular dynamics (MD) simulations corroborated experimental data and demonstrated the significance of surface functional groups on ion orientations, accumulation densities, and capacitance.

  17. Pulsed laser stereophotography of plasmas and dynamically moving surfaces

    International Nuclear Information System (INIS)

    Paisley, D.L.

    1987-01-01

    A pulsed laser is used as a light source for illuminating the surface of a dynamic event of 3 mm//μs. At a predetermined time during the dynamic action, a stereo camera is used to record a pair of images of the dynamically moving surface. The stereoimage pair can be quantified for surface contour

  18. GRACE storage-runoff hystereses reveal the dynamics of ...

    Science.gov (United States)

    Watersheds function as integrated systems where climate and geology govern the movement of water. In situ instrumentation can provide local-scale insights into the non-linear relationship between streamflow and water stored in a watershed as snow, soil moisture, and groundwater. However, there is a poor understanding of these processes at the regional scale—primarily because of our inability to measure water stores and fluxes in the subsurface. Now NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites quantify changes in the amount of water stored across and through the Earth, providing measurements of regional hydrologic behavior. Here we apply GRACE data to characterize for the first time how regional watersheds function as simple, dynamic systems through a series of hysteresis loops. While the physical processes underlying the loops are inherently complex, the vertical integration of terrestrial water in the GRACE signal provides process-based insights into the dynamic and non-linear function of regional-scale watersheds. We use this process-based understanding with GRACE data to effectively forecast seasonal runoff (mean R2 of 0.91) and monthly runoff (mean R2 of 0.77) in three regional-scale watersheds (>150,000 km2) of the Columbia River Basin, USA. Data from the Gravity Recovery and Climate Experiment (GRACE) satellites provide a novel dataset for understanding changes in the amount of water stored across and through the surface of the Ear

  19. Impact of environmental conditions on sub-surface storage tanks ...

    African Journals Online (AJOL)

    Cast iron made storage tanks with gasoline fluid were buried under the soil at a depth of 4 m under various environment conditions. The simulated conditions include natural rain fail, temperature and acidic, alkaline and neutral soils. A control condition of neutral sea sand as base and filling materials were also investigated.

  20. Microbial Internal Storage Alters the Carbon Transformation in Dynamic Anaerobic Fermentation.

    Science.gov (United States)

    Ni, Bing-Jie; Batstone, Damien; Zhao, Bai-Hang; Yu, Han-Qing

    2015-08-04

    Microbial internal storage processes have been demonstrated to occur and play an important role in activated sludge systems under both aerobic and anoxic conditions when operating under dynamic conditions. High-rate anaerobic reactors are often operated at a high volumetric organic loading and a relatively dynamic profile, with large amounts of fermentable substrates. These dynamic operating conditions and high catabolic energy availability might also facilitate the formation of internal storage polymers by anaerobic microorganisms. However, so far information about storage under anaerobic conditions (e.g., anaerobic fermentation) as well as its consideration in anaerobic process modeling (e.g., IWA Anaerobic Digestion Model No. 1, ADM1) is still sparse. In this work, the accumulation of storage polymers during anaerobic fermentation was evaluated by batch experiments using anaerobic methanogenic sludge and based on mass balance analysis of carbon transformation. A new mathematical model was developed to describe microbial storage in anaerobic systems. The model was calibrated and validated by using independent data sets from two different anaerobic systems, with significant storage observed, and effectively simulated in both systems. The inclusion of the new anaerobic storage processes in the developed model allows for more successful simulation of transients due to lower accumulation of volatile fatty acids (correction for the overestimation of volatile fatty acids), which mitigates pH fluctuations. Current models such as the ADM1 cannot effectively simulate these dynamics due to a lack of anaerobic storage mechanisms.

  1. Effects of storage methods on time-related changes of titanium surface properties and cellular response

    International Nuclear Information System (INIS)

    Lu Haibin; Zhou Lei; Wan Lei; Li Shaobing; Rong Mingdeng; Guo Zehong

    2012-01-01

    Titanium implants are sold in the market as storable medical devices. All the implants have a certain shelf life during which they maintain their sterility, but variations of the surface properties through this duration have not been subject to a comprehensive assessment. The aim of this study was to investigate the effects of storage methods on time-related changes of titanium surface properties. Acid-etched titanium discs (Sa = 0.82 µm) were placed in a sealed container (tradition method) or submerged in the ddH 2 O/NaCl solution (0.15 mol L −1 )/CaCl 2 solution (0.15 mol L −1 ), and new titanium discs were used as a control group. SEM and optical profiler showed that surface morphology and roughness did not change within different groups, but the XPS analysis confirmed that the surface chemistry altered by different storage protocols as the storage duration increased, and the contact angle also varied with storage methods. The storage method also affected the protein adsorption capacity and cellular response on the titanium surface. All titanium discs stored in the solution maintained their excellent bioactivity even after four weeks storage time, but titanium discs stored in a traditional manner decreased substantially in an age-dependent manner. Much effort is needed to improve the storage methods in order to maintain the bioactivity of a titanium dental implant. (paper)

  2. Theory and analysis of nonlinear dynamics and stability in storage rings: A working group summary

    International Nuclear Information System (INIS)

    Chattopadhyay, S.; Audy, P.; Courant, E.D.

    1988-07-01

    A summary and commentary of the available theoretical and analytical tools and recent advances in the nonlinear dynamics, stability and aperture issues in storage rings are presented. 11 refs., 4 figs

  3. Electrode surface engineering by atomic layer deposition: A promising pathway toward better energy storage

    KAUST Repository

    Ahmed, Bilal; Xia, Chuan; Alshareef, Husam N.

    2016-01-01

    high capacities and energy and power densities. These developments can extend battery life in portable devices, and open new markets such as electric vehicles and large-scale grid energy storage. It is well known that surface reactions largely determine

  4. Adsorption thermal energy storage for cogeneration in industrial batch processes: Experiment, dynamic modeling and system analysis

    International Nuclear Information System (INIS)

    Schreiber, Heike; Graf, Stefan; Lanzerath, Franz; Bardow, André

    2015-01-01

    Adsorption thermal energy storage is investigated for heat supply with cogeneration in industrial batch processes. The feasibility of adsorption thermal energy storage is demonstrated with a lab-scale prototype. Based on these experiments, a dynamic model is developed and successfully calibrated to measurement data. Thereby, a reliable description of the dynamic behavior of the adsorption thermal energy storage unit is achieved. The model is used to study and benchmark the performance of adsorption thermal energy storage combined with cogeneration for batch process energy supply. As benchmark, we consider both a peak boiler and latent thermal energy storage based on a phase change material. Beer brewing is considered as an example of an industrial batch process. The study shows that adsorption thermal energy storage has the potential to increase energy efficiency significantly; primary energy consumption can be reduced by up to 25%. However, successful integration of adsorption thermal storage requires appropriate integration of low grade heat: Preferentially, low grade heat is available at times of discharging and in demand when charging the storage unit. Thus, adsorption thermal energy storage is most beneficial if applied to a batch process with heat demands on several temperature levels. - Highlights: • A highly efficient energy supply for industrial batch processes is presented. • Adsorption thermal energy storage (TES) is analyzed in experiment and simulation. • Adsorption TES can outperform both peak boilers and latent TES. • Performance of adsorption TES strongly depends on low grade heat temperature.

  5. Orbital dynamics in a storage ring with electrostatic bending

    International Nuclear Information System (INIS)

    Mane, S.R.

    2008-01-01

    A storage ring where electrostatic fields contribute to the bending and focusing of the orbital motion has some novel features because, unlike a magnetostatic field, an electrostatic field can change the kinetic energy of the particles. I present analytical formulas to calculate the linear focusing gradient, dispersion, momentum compaction and natural chromaticity for a storage ring with a radial electrostatic field. I solve the formulas explicitly for a weak focusing model.

  6. Energy storage considerations for a robotic Mars surface sampler

    International Nuclear Information System (INIS)

    O'Donnell, P.M.; Cataldo, R.L.; Gonzalez-Sanabria, O.D.

    1988-01-01

    Manned exploration of Mars is being proposed by the National Commission on Space for the next century. To accomplish this task with minimal resupply cost for extended stay times, use of Mars' resources is essential. Methods must be developed to manufacture or extract water and oxygen from elements indigenous to Mars before they send explorers to the planet. Therefore, they must send precursor surveying equipment to determine Mars' resources to a greater extent than is now known from Viking 1 and Viking 2 data. A 1992 launch is planned for the Mars Observer that will contribute greater mapping resolution and expand the scientific data base. The proposed rover will provide scientists with the necessary information about abundant resources that would guide the required technology development needed to support a manned Mars infrastructure. The actual rover operations plan for both the sample return and extended mission will have a large impact on rover capabilities and the power system supplying power for traversing and scientific instrumentation. POWER SOURCE AND CONVERSION. Several power source/conversion options for the rover have been identified. These include power generation on the lander, Entry Vehicle (EV), Mars Orbiter Vehicle (MOV) and on the rover itself. Power from the lander would require the rover to return to landing site to recharge the energy storage systems, which limits rover excursions to one-half the range of the storage capacity. For on-board rover power, a Radioisotope Thermoelectric Generator (RTG) has been considered with the appropriate energy storage to handle peak power demands

  7. Static and dynamic friction of hierarchical surfaces.

    Science.gov (United States)

    Costagliola, Gianluca; Bosia, Federico; Pugno, Nicola M

    2016-12-01

    Hierarchical structures are very common in nature, but only recently have they been systematically studied in materials science, in order to understand the specific effects they can have on the mechanical properties of various systems. Structural hierarchy provides a way to tune and optimize macroscopic mechanical properties starting from simple base constituents and new materials are nowadays designed exploiting this possibility. This can be true also in the field of tribology. In this paper we study the effect of hierarchical patterned surfaces on the static and dynamic friction coefficients of an elastic material. Our results are obtained by means of numerical simulations using a one-dimensional spring-block model, which has previously been used to investigate various aspects of friction. Despite the simplicity of the model, we highlight some possible mechanisms that explain how hierarchical structures can significantly modify the friction coefficients of a material, providing a means to achieve tunability.

  8. Dynamic federations: storage aggregation using open tools and protocols

    International Nuclear Information System (INIS)

    Furano, Fabrizio; Brito da Rocha, Ricardo; Devresse, Adrien; Keeble, Oliver; Álvarez Ayllón, Alejandro; Fuhrmann, Patrick

    2012-01-01

    A number of storage elements now offer standard protocol interfaces like NFS 4.1/pNFS and WebDAV, for access to their data repositories, in line with the standardization effort of the European Middleware Initiative (EMI). Also the LCG FileCatalogue (LFC) can offer such features. Here we report on work that seeks to exploit the federation potential of these protocols and build a system that offers a unique view of the storage and metadata ensemble and the possibility of integration of other compatible resources such as those from cloud providers. The challenge, here undertaken by the providers of dCache and DPM, and pragmatically open to other Grid and Cloud storage solutions, is to build such a system while being able to accommodate name translations from existing catalogues (e.g. LFCs), experiment-based metadata catalogues, or stateless algorithmic name translations, also known as “trivial file catalogues”. Such so-called storage federations of standard protocols-based storage elements give a unique view of their content, thus promoting simplicity in accessing the data they contain and offering new possibilities for resilience and data placement strategies. The goal is to consider HTTP and NFS4.1-based storage elements and metadata catalogues and make them able to cooperate through an architecture that properly feeds the redirection mechanisms that they are based upon, thus giving the functionalities of a “loosely coupled” storage federation. One of the key requirements is to use standard clients (provided by OS'es or open source distributions, e.g. Web browsers) to access an already aggregated system; this approach is quite different from aggregating the repositories at the client side through some wrapper API, like for instance GFAL, or by developing new custom clients. Other technical challenges that will determine the success of this initiative include performance, latency and scalability, and the ability to create worldwide storage federations that

  9. Influences of biomass heat and biochemical energy storages on the land surface fluxes and radiative temperature

    Science.gov (United States)

    Gu, Lianhong; Meyers, Tilden; Pallardy, Stephen G.; Hanson, Paul J.; Yang, Bai; Heuer, Mark; Hosman, Kevin P.; Liu, Qing; Riggs, Jeffery S.; Sluss, Dan; Wullschleger, Stan D.

    2007-01-01

    The interest of this study was to develop an initial assessment on the potential importance of biomass heat and biochemical energy storages for land-atmosphere interactions, an issue that has been largely neglected so far. We conducted flux tower observations and model simulations at a temperate deciduous forest site in central Missouri in the summer of 2004. The model used was the comprehensive terrestrial ecosystem Fluxes and Pools Integrated Simulator (FAPIS). We first examined FAPIS performance by testing its predictions with and without the representation of biomass energy storages against measurements of surface energy and CO2 fluxes. We then evaluated the magnitudes and temporal patterns of the biomass energy storages calculated by FAPIS. Finally, the effects of biomass energy storages on land-atmosphere exchanges of sensible and latent heat fluxes and variations of land surface radiative temperature were investigated by contrasting FAPIS simulations with and without these storage terms. We found that with the representation of the two biomass energy storage terms, FAPIS predictions agreed with flux tower measurements fairly well; without the representation, however, FAPIS performance deteriorated for all predicted surface energy flux terms although the effect on the predicted CO2 flux was minimal. In addition, we found that the biomass heat storage and biochemical energy storage had clear diurnal patterns with typical ranges from -50 to 50 and -3 to 20 W m-2, respectively; these typical ranges were exceeded substantially when there were sudden changes in atmospheric conditions. Furthermore, FAPIS simulations without the energy storages produced larger sensible and latent heat fluxes during the day but smaller fluxes (more negative values) at night as compared with simulations with the energy storages. Similarly, without-storage simulations had higher surface radiative temperature during the day but lower radiative temperature at night, indicating that the

  10. Dynamic federations: storage aggregation using open tools and protocols

    CERN Document Server

    Fabrizio Furano, F F; Ricardo Brito da Rocha, R R; Adrien Devresse, A D; Oliver Keeble, O K; Alejandro Alvarez Ayllon, A A

    2012-01-01

    A number of storage elements now offer standard protocol interfaces like NFS 4.1/pNFS and WebDAV, for access to their data repositories, in line with the standardization effort of the European Middleware Initiative (EMI). Also the LCG FileCatalogue (LFC) can offer such features. Here we report on work that seeks to exploit the federation potential of these protocols and build a system that offers a unique view of the storage and metadata ensemble and the possibility of integration of other compatible resources such as those from cloud providers. The challenge, here undertaken by the providers of dCache and DPM, and pragmatically open to other Grid and Cloud storage solutions, is to build such a system while being able to accommodate name translations from existing catalogues (e.g. LFCs), experiment- based metadata catalogues, or stateless algorithmic name translations, also known as ”trivial file catalogues”. Such so-called storage federations of standard protocols-based storage elements give a unique vie...

  11. Influence of dynamic vegetation on climate change and terrestrial carbon storage in the Last Glacial Maximum

    Science.gov (United States)

    O'ishi, R.; Abe-Ouchi, A.

    2013-07-01

    When the climate is reconstructed from paleoevidence, it shows that the Last Glacial Maximum (LGM, ca. 21 000 yr ago) is cold and dry compared to the present-day. Reconstruction also shows that compared to today, the vegetation of the LGM is less active and the distribution of vegetation was drastically different, due to cold temperature, dryness, and a lower level of atmospheric CO2 concentration (185 ppm compared to a preindustrial level of 285 ppm). In the present paper, we investigate the influence of vegetation change on the climate of the LGM by using a coupled atmosphere-ocean-vegetation general circulation model (AOVGCM, the MIROC-LPJ). The MIROC-LPJ is different from earlier studies in the introduction of a bias correction method in individual running GCM experiments. We examined four GCM experiments (LGM and preindustrial, with and without vegetation feedback) and quantified the strength of the vegetation feedback during the LGM. The result shows that global-averaged cooling during the LGM is amplified by +13.5 % due to the introduction of vegetation feedback. This is mainly caused by the increase of land surface albedo due to the expansion of tundra in northern high latitudes and the desertification in northern middle latitudes around 30° N to 60° N. We also investigated how this change in climate affected the total terrestrial carbon storage by using offline Lund-Potsdam-Jena dynamic global vegetation model (LPJ-DGVM). Our result shows that the total terrestrial carbon storage was reduced by 597 PgC during the LGM, which corresponds to the emission of 282 ppm atmospheric CO2. In the LGM experiments, the global carbon distribution is generally the same whether the vegetation feedback to the atmosphere is included or not. However, the inclusion of vegetation feedback causes substantial terrestrial carbon storage change, especially in explaining the lowering of atmospheric CO2 during the LGM.

  12. Influence of dynamic vegetation on climate change and terrestrial carbon storage in the Last Glacial Maximum

    Directory of Open Access Journals (Sweden)

    R. O'ishi

    2013-07-01

    Full Text Available When the climate is reconstructed from paleoevidence, it shows that the Last Glacial Maximum (LGM, ca. 21 000 yr ago is cold and dry compared to the present-day. Reconstruction also shows that compared to today, the vegetation of the LGM is less active and the distribution of vegetation was drastically different, due to cold temperature, dryness, and a lower level of atmospheric CO2 concentration (185 ppm compared to a preindustrial level of 285 ppm. In the present paper, we investigate the influence of vegetation change on the climate of the LGM by using a coupled atmosphere-ocean-vegetation general circulation model (AOVGCM, the MIROC-LPJ. The MIROC-LPJ is different from earlier studies in the introduction of a bias correction method in individual running GCM experiments. We examined four GCM experiments (LGM and preindustrial, with and without vegetation feedback and quantified the strength of the vegetation feedback during the LGM. The result shows that global-averaged cooling during the LGM is amplified by +13.5 % due to the introduction of vegetation feedback. This is mainly caused by the increase of land surface albedo due to the expansion of tundra in northern high latitudes and the desertification in northern middle latitudes around 30° N to 60° N. We also investigated how this change in climate affected the total terrestrial carbon storage by using offline Lund-Potsdam-Jena dynamic global vegetation model (LPJ-DGVM. Our result shows that the total terrestrial carbon storage was reduced by 597 PgC during the LGM, which corresponds to the emission of 282 ppm atmospheric CO2. In the LGM experiments, the global carbon distribution is generally the same whether the vegetation feedback to the atmosphere is included or not. However, the inclusion of vegetation feedback causes substantial terrestrial carbon storage change, especially in explaining the lowering of atmospheric CO2 during the LGM.

  13. DYNAMICS AND INTENSITY OF APLE DISEASE DEVELOPMENT DURING ITS STORAGE

    Directory of Open Access Journals (Sweden)

    D. Ivić

    2006-12-01

    Full Text Available Post-harvest apple fruit diseases are primarily caused by fungi. The object of this research was to quantify yield loss caused by post-harvest diseases and to determine fungal species responsible for storage rots on the cv. Idared during three months of storage, as well as to compare the development of fungi inoculated on apple fruits in the laboratory conditions. Only fruits with the visible rot symptoms were regarded as "diseased". Total yield loss during all three months of storage was 1.9%. The percentage of diseased fruits increased from the harvest moment to the end of storage. The most frequent cause of post-harvest rot in all assessments was Monilia fructigena. Penicillium species and Botrytis cinerea were present in relatively high percentage. All fungal isolates from diseased fruits caused fruit rot when inoculated on apples and incubated for 28 days at 22°C. On fruits inoculated with the same isolates and incubated at 4°C rot development was slower. Isolates of M. fructigena developed most rapidly on inoculated fruits at 22°C, while the isolates of B. cinerea developed most rapidly at 4°C.

  14. Groundwater chemistry, storage and dynamics in parts of Jigawa ...

    African Journals Online (AJOL)

    The Sedimentary (Chad formation) and Basement complex rocks in parts of Jigawa State were investigated for groundwater suitability for drinking, efficiency in water transmission and storage using aquifer properties derived from pumping test data using the Cooper and Jacob straight line method for single well tests.

  15. LANL Virtual Center for Chemical Hydrogen Storage: Chemical Hydrogen Storage Using Ultra-high Surface Area Main Group Materials

    Energy Technology Data Exchange (ETDEWEB)

    Susan M. Kauzlarich; Phillip P. Power; Doinita Neiner; Alex Pickering; Eric Rivard; Bobby Ellis, T. M.; Atkins, A. Merrill; R. Wolf; Julia Wang

    2010-09-05

    The focus of the project was to design and synthesize light element compounds and nanomaterials that will reversibly store molecular hydrogen for hydrogen storage materials. The primary targets investigated during the last year were amine and hydrogen terminated silicon (Si) nanoparticles, Si alloyed with lighter elements (carbon (C) and boron (B)) and boron nanoparticles. The large surface area of nanoparticles should facilitate a favorable weight to volume ratio, while the low molecular weight elements such as B, nitrogen (N), and Si exist in a variety of inexpensive and readily available precursors. Furthermore, small NPs of Si are nontoxic and non-corrosive. Insights gained from these studies will be applied toward the design and synthesis of hydrogen storage materials that meet the DOE 2010 hydrogen storage targets: cost, hydrogen capacity and reversibility. Two primary routes were explored for the production of nanoparticles smaller than 10 nm in diameter. The first was the reduction of the elemental halides to achieve nanomaterials with chloride surface termination that could subsequently be replaced with amine or hydrogen. The second was the reaction of alkali metal Si or Si alloys with ammonium halides to produce hydrogen capped nanomaterials. These materials were characterized via X-ray powder diffraction, TEM, FTIR, TG/DSC, and NMR spectroscopy.

  16. Formation of filtration fields close to near-surface radioactive waste storages

    International Nuclear Information System (INIS)

    Mart'yanov, V.V.

    2008-01-01

    Data on the formation of filtration fields in the location of near-surface radioactive waste storages for the conditions of uniformly isotropic properties of bearing strata are demonstrated. The possibility for changing parameters of mean-caused ground flow depending on water permeability of the storages and their dimensions in plan is noted. Comparison of different filtration fields permits to determine a state of its isolating properties. Assessment criteria of the storage engineering barriers integrity are given. Conditions for uniformly isotropic properties of bearing strata by three scenarios, when engineering barriers of the storage are waterproof, distracted or lost protective properties in full, have been determined. Changing filtration field, geochemical and radiochemical situations in bearing strata are noted to represent one of basic characteristics of the integrity of the storage [ru

  17. Technical Note: Comparison of storage strategies of sea surface microlayer samples

    Directory of Open Access Journals (Sweden)

    K. Schneider-Zapp

    2013-07-01

    Full Text Available The sea surface microlayer (SML is an important biogeochemical system whose physico-chemical analysis often necessitates some degree of sample storage. However, many SML components degrade with time so the development of optimal storage protocols is paramount. We here briefly review some commonly used treatment and storage protocols. Using freshwater and saline SML samples from a river estuary, we investigated temporal changes in surfactant activity (SA and the absorbance and fluorescence of chromophoric dissolved organic matter (CDOM over four weeks, following selected sample treatment and storage protocols. Some variability in the effectiveness of individual protocols most likely reflects sample provenance. None of the various protocols examined performed any better than dark storage at 4 °C without pre-treatment. We therefore recommend storing samples refrigerated in the dark.

  18. Modelling surface-water depression storage in a Prairie Pothole Region

    Science.gov (United States)

    Hay, Lauren E.; Norton, Parker A.; Viger, Roland; Markstrom, Steven; Regan, R. Steven; Vanderhoof, Melanie

    2018-01-01

    In this study, the Precipitation-Runoff Modelling System (PRMS) was used to simulate changes in surface-water depression storage in the 1,126-km2 Upper Pipestem Creek basin located within the Prairie Pothole Region of North Dakota, USA. The Prairie Pothole Region is characterized by millions of small water bodies (or surface-water depressions) that provide numerous ecosystem services and are considered an important contribution to the hydrologic cycle. The Upper Pipestem PRMS model was extracted from the U.S. Geological Survey's (USGS) National Hydrologic Model (NHM), developed to support consistent hydrologic modelling across the conterminous United States. The Geospatial Fabric database, created for the USGS NHM, contains hydrologic model parameter values derived from datasets that characterize the physical features of the entire conterminous United States for 109,951 hydrologic response units. Each hydrologic response unit in the Geospatial Fabric was parameterized using aggregated surface-water depression area derived from the National Hydrography Dataset Plus, an integrated suite of application-ready geospatial datasets. This paper presents a calibration strategy for the Upper Pipestem PRMS model that uses normalized lake elevation measurements to calibrate the parameters influencing simulated fractional surface-water depression storage. Results indicate that inclusion of measurements that give an indication of the change in surface-water depression storage in the calibration procedure resulted in accurate changes in surface-water depression storage in the water balance. Regionalized parameterization of the USGS NHM will require a proxy for change in surface-storage to accurately parameterize surface-water depression storage within the USGS NHM.

  19. Surface Freshwater Storage Variations in the Orinoco Floodplains Using Multi-Satellite Observations

    Directory of Open Access Journals (Sweden)

    Frédéric Frappart

    2014-12-01

    Full Text Available Variations in surface water extent and storage are poorly characterized from regional to global scales. In this study, a multi-satellite approach is proposed to estimate the water stored in the floodplains of the Orinoco Basin at a monthly time-scale using remotely-sensed observations of surface water from the Global Inundation Extent Multi-Satellite (GIEMS and stages from Envisat radar altimetry. Surface water storage variations over 2003–2007 exhibit large interannual variability and a strong seasonal signal, peaking during summer, and associated with the flood pulse. The volume of surface water storage in the Orinoco Basin was highly correlated with the river discharge at Ciudad Bolivar (R = 0.95, the closest station to the mouth where discharge was estimated, although discharge lagged one month behind storage. The correlation remained high (R = 0.73 after removing seasonal effects. Mean annual variations in surface water volume represented ~170 km3, contributing to ~45% of the Gravity Recovery and Climate Experiment (GRACE-derived total water storage variations and representing ~13% of the total volume of water that flowed out of the Orinoco Basin to the Atlantic Ocean.

  20. Dynamics of Storage Carbohydrates Metabolism in Saccharomyces cerevisiae

    OpenAIRE

    Suarez-Mendez, C.A.

    2015-01-01

    Production of chemicals via biotechnological routes are becoming rapidly an alternative to oil-based processes. Several microorganisms including yeast, bacteria, fungi and algae can transform feedstocks into high-value molecules at industrial scale. Improvement of the bioprocess performance is a key factor for making this technology economically feasible. Despite the vast knowledge on microbial metabolism, some gaps still remain open. In Saccharomyces cerevisiae, metabolism of storage carbohy...

  1. A secure and efficient audit mechanism for dynamic shared data in cloud storage.

    Science.gov (United States)

    Kwon, Ohmin; Koo, Dongyoung; Shin, Yongjoo; Yoon, Hyunsoo

    2014-01-01

    With popularization of cloud services, multiple users easily share and update their data through cloud storage. For data integrity and consistency in the cloud storage, the audit mechanisms were proposed. However, existing approaches have some security vulnerabilities and require a lot of computational overheads. This paper proposes a secure and efficient audit mechanism for dynamic shared data in cloud storage. The proposed scheme prevents a malicious cloud service provider from deceiving an auditor. Moreover, it devises a new index table management method and reduces the auditing cost by employing less complex operations. We prove the resistance against some attacks and show less computation cost and shorter time for auditing when compared with conventional approaches. The results present that the proposed scheme is secure and efficient for cloud storage services managing dynamic shared data.

  2. Optimal Sizing of Energy Storage for Community Microgrids Considering Building Thermal Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guodong [ORNL; Li, Zhi [ORNL; Starke, Michael R. [ORNL; Ollis, Ben [ORNL; Tomsovic, Kevin [University of Tennessee, Knoxville (UTK)

    2017-07-01

    This paper proposes an optimization model for the optimal sizing of energy storage in community microgrids considering the building thermal dynamics and customer comfort preference. The proposed model minimizes the annualized cost of the community microgrid, including energy storage investment, purchased energy cost, demand charge, energy storage degradation cost, voluntary load shedding cost and the cost associated with customer discomfort due to room temperature deviation. The decision variables are the power and energy capacity of invested energy storage. In particular, we assume the heating, ventilation and air-conditioning (HVAC) systems can be scheduled intelligently by the microgrid central controller while maintaining the indoor temperature in the comfort range set by customers. For this purpose, the detailed thermal dynamic characteristics of buildings have been integrated into the optimization model. Numerical simulation shows significant cost reduction by the proposed model. The impacts of various costs on the optimal solution are investigated by sensitivity analysis.

  3. A Secure and Efficient Audit Mechanism for Dynamic Shared Data in Cloud Storage

    Science.gov (United States)

    2014-01-01

    With popularization of cloud services, multiple users easily share and update their data through cloud storage. For data integrity and consistency in the cloud storage, the audit mechanisms were proposed. However, existing approaches have some security vulnerabilities and require a lot of computational overheads. This paper proposes a secure and efficient audit mechanism for dynamic shared data in cloud storage. The proposed scheme prevents a malicious cloud service provider from deceiving an auditor. Moreover, it devises a new index table management method and reduces the auditing cost by employing less complex operations. We prove the resistance against some attacks and show less computation cost and shorter time for auditing when compared with conventional approaches. The results present that the proposed scheme is secure and efficient for cloud storage services managing dynamic shared data. PMID:24959630

  4. Hydration dynamics near a model protein surface

    International Nuclear Information System (INIS)

    Russo, Daniela; Hura, Greg; Head-Gordon, Teresa

    2003-01-01

    The evolution of water dynamics from dilute to very high concentration solutions of a prototypical hydrophobic amino acid with its polar backbone, N-acetyl-leucine-methylamide (NALMA), is studied by quasi-elastic neutron scattering and molecular dynamics simulation for both the completely deuterated and completely hydrogenated leucine monomer. We observe several unexpected features in the dynamics of these biological solutions under ambient conditions. The NALMA dynamics shows evidence of de Gennes narrowing, an indication of coherent long timescale structural relaxation dynamics. The translational water dynamics are analyzed in a first approximation with a jump diffusion model. At the highest solute concentrations, the hydration water dynamics is significantly suppressed and characterized by a long residential time and a slow diffusion coefficient. The analysis of the more dilute concentration solutions takes into account the results of the 2.0M solution as a model of the first hydration shell. Subtracting the first hydration layer based on the 2.0M spectra, the translational diffusion dynamics is still suppressed, although the rotational relaxation time and residential time are converged to bulk-water values. Molecular dynamics analysis shows spatially heterogeneous dynamics at high concentration that becomes homogeneous at more dilute concentrations. We discuss the hydration dynamics results of this model protein system in the context of glassy systems, protein function, and protein-protein interfaces

  5. Research on the Measurement of Carbon Storage in Plantation Tree Trunks Based on the Carbon Storage Dynamic Analysis Method

    Directory of Open Access Journals (Sweden)

    Weida Yin

    2012-01-01

    Full Text Available Estimation of forest carbon storage can be of great significance to the research on the productivity of terrestrial ecosystem, carbon cycle, and global warming. China has more than 54 million hm2 barren hills and waste land suitable for forestation, which provides a great potential for developing carbon sink forestry by means of forestation. This research analyzed the volume increments, volume densities, and carbon contents of 15 analytical samples of five main plantation tree species in North China, including Pinus tabulaeformis (A, Robinia pseudoacacia (B, Populus euramericana (C, Larix olgenisis (D, and Larix kaempferi (E. Results showed that carbon storage dynamic process can be expressed as follows: the ages of quantitative maturity of each tree species are 67a, 40a, 30a, 48a, 49a, respectively; the average wood densities of each tree species at different age classes are 550.93 kg/m3, 629.25 kg/m3, 404.56 kg/m3, 592.33 kg/m3, and 544.11 kg/m3,t. The average carbon contents of each tree species at different age classes are 51.48%, 46.88%, 47.81%, 46.76%, and 47.24%. It showed a significant difference between the above tree species through variance test. The maximum values of average carbon storage are 70a, 40a, 30a, 48.7a, and 49.2a, respectively. The corresponding average carbon storages are A 2.527 kg, B 3,794 kg, C 2.781 kg, D 2.996 kg, and E 3,322 kg, in a descending order of C>E>D>B>A. This research, through experiment on four tree species with clear growth rings and one tree species with unclear growth rings, verified the scientific character and the scope of application of the carbon storage dynamic analysis method, providing a new method for the measurement and analysis of forest carbon storage.

  6. An adaptive cryptographic accelerator for network storage security on dynamically reconfigurable platform

    Science.gov (United States)

    Tang, Li; Liu, Jing-Ning; Feng, Dan; Tong, Wei

    2008-12-01

    Existing security solutions in network storage environment perform poorly because cryptographic operations (encryption and decryption) implemented in software can dramatically reduce system performance. In this paper we propose a cryptographic hardware accelerator on dynamically reconfigurable platform for the security of high performance network storage system. We employ a dynamic reconfigurable platform based on a FPGA to implement a PowerPCbased embedded system, which executes cryptographic algorithms. To reduce the reconfiguration latency, we apply prefetch scheduling. Moreover, the processing elements could be dynamically configured to support different cryptographic algorithms according to the request received by the accelerator. In the experiment, we have implemented AES (Rijndael) and 3DES cryptographic algorithms in the reconfigurable accelerator. Our proposed reconfigurable cryptographic accelerator could dramatically increase the performance comparing with the traditional software-based network storage systems.

  7. The decontamination of soft-plated nickel surfaces compared to alternative surface materials used in radioactive transport and storage containers

    International Nuclear Information System (INIS)

    Zwicky, H.U.; Bedenig, D.O.; Bohringer, I.M.; Petrik, F.

    1983-01-01

    Surfaces of raw, nickel-plated, and epoxy-coated spheroidal graphite cast iron, together with stainless steel, were contaminated with a modified fission product solution then conditioned by heat treatment. This was followed by a variety of simple decontamination techniques. It was shown that the ease of removal of contaminations similar to those expected on a dry storage container surface is significantly affected by the roughness of the surface. The raw cast iron surface was virtually impossible to significantly decontaminate. Highest decontamination factors were obtained on nickel-plated and epoxy-painted surfaces using steam/detergent mixtures. Stainless steel only performed well in a polished condition. In a supplementary irradiation experiment, scanning electron microscopy indicated visible decomposition of an epoxy-painted surface at a gamma dose of 3.1 X 10 6 Gy (3.1 X 10 8 rad). A nickel-plated surface did not undergo any visible changes at the same dose

  8. A modeling of dynamic storage assignment for order picking in beverage warehousing with Drive-in Rack system

    Science.gov (United States)

    Hadi, M. Z.; Djatna, T.; Sugiarto

    2018-04-01

    This paper develops a dynamic storage assignment model to solve storage assignment problem (SAP) for beverages order picking in a drive-in rack warehousing system to determine the appropriate storage location and space for each beverage products dynamically so that the performance of the system can be improved. This study constructs a graph model to represent drive-in rack storage position then combine association rules mining, class-based storage policies and an arrangement rule algorithm to determine an appropriate storage location and arrangement of the product according to dynamic orders from customers. The performance of the proposed model is measured as rule adjacency accuracy, travel distance (for picking process) and probability a product become expiry using Last Come First Serve (LCFS) queue approach. Finally, the proposed model is implemented through computer simulation and compare the performance for different storage assignment methods as well. The result indicates that the proposed model outperforms other storage assignment methods.

  9. Dynamic modeling of stratification for chilled water storage tank

    International Nuclear Information System (INIS)

    Osman, Kahar; Al Khaireed, Syed Muhammad Nasrul; Ariffin, Mohd Kamal; Senawi, Mohd Yusoff

    2008-01-01

    Air conditioning of buildings can be costly and energy consuming. Application of thermal energy storage (TES) reduces cost and energy consumption. The efficiency of the overall operation is affected by storage tank sizing design, which affects thermal stratification of water during charging and discharging processes in TES system. In this study, numerical simulation is used to determine the relationship between tank size and good thermal stratification. Three dimensional simulations with different tank height-to-diameter ratio (HD) and inlet Reynolds number (Re) are investigated. The effect of the number of diffuser holes is also studied. For shallow tanks (low HD) simulations, no acceptable thermocline thickness can be seen for all Re experimented. Partial mixing is observed throughout the process. Medium HD tanks simulations show good thermocline behavior and clear distinction between warm and cold water can be seen. Finally, deep tanks (high HD) show less acceptable thermocline thickness as compared to that of medium HD tanks. From this study, doubling and halving the number of diffuser holes show no significant effect on the thermocline behavior

  10. New chromaticity compensation approach and dynamic aperture increase in the SSRF storage ring

    International Nuclear Information System (INIS)

    Tian Shunqiang; Hou Jie; Chen Guangling; Chinese Academy of Sciences, Beijing; Liu Guimin

    2008-01-01

    Strong chromatic sextupoles used to compensate natural chromaticities in the third generation light source storage ring usually reduce dynamic aperture drastically. Many optimization methods can be used to find solutions that provide large dynamic apertures. This paper discusses a new optimization approach of sextupole strengths with step-by-step procedure, which is applied in the SSRF storage ring, and a better solution is obtained. Investigating driving terms generated by the sextupoles in every step can analyze their convergences and guide the weight setting among different terms in object function of the single resonance approach based on the perturbation theory. (authors)

  11. Dynamic Equilibrium Mechanism for Surface Nanobubble Stabilization

    NARCIS (Netherlands)

    Brenner, Michael P.; Lohse, Detlef

    2008-01-01

    Recent experiments have convincingly demonstrated the existence of surface nanobubbles on submerged hydrophobic surfaces. However, classical theory dictates that small gaseous bubbles quickly dissolve because their large Laplace pressure causes a diffusive outflux of gas. Here we suggest that the

  12. Atomic probes of surface structure and dynamics

    International Nuclear Information System (INIS)

    Heller, E.J.; Jonsson, H.

    1992-01-01

    The following were studied: New semiclassical method for scattering calculations, He atom scattering from defective Pt surfaces, He atom scattering from Xe overlayers, thermal dissociation of H 2 on Cu(110), spin flip scattering of atoms from surfaces, and Car-Parrinello simulations of surface processes

  13. A nuclear fuel cycle system dynamic model for spent fuel storage options

    International Nuclear Information System (INIS)

    Brinton, Samuel; Kazimi, Mujid

    2013-01-01

    Highlights: • Used nuclear fuel management requires a dynamic system analysis study due to its socio-technical complexity. • Economic comparison of local, regional, and national storage options is limited due to the public financial information. • Local and regional options of used nuclear fuel management are found to be the most economic means of storage. - Abstract: The options for used nuclear fuel storage location and affected parameters such as economic liabilities are currently a focus of several high level studies. A variety of nuclear fuel cycle system analysis models are available for such a task. The application of nuclear fuel cycle system dynamics models for waste management options is important to life-cycle impact assessment. The recommendations of the Blue Ribbon Committee on America’s Nuclear Future led to increased focus on long periods of spent fuel storage [1]. This motivated further investigation of the location dependency of used nuclear fuel in the parameters of economics, environmental impact, and proliferation risk. Through a review of available literature and interactions with each of the programs available, comparisons of post-reactor fuel storage and handling options will be evaluated based on the aforementioned parameters and a consensus of preferred system metrics and boundary conditions will be provided. Specifically, three options of local, regional, and national storage were studied. The preliminary product of this research is the creation of a system dynamics tool known as the Waste Management Module (WMM) which provides an easy to use interface for education on fuel cycle waste management economic impacts. Initial results of baseline cases point to positive benefits of regional storage locations with local regional storage options continuing to offer the lowest cost

  14. Spin dynamics in storage rings and linear accelerators

    International Nuclear Information System (INIS)

    Irwin, J.

    1994-04-01

    The purpose of these lectures is to survey the subject of spin dynamics in accelerators: to give a sense of the underlying physics, the typical analytic and numeric methods used, and an overview of results achieved. Consideration will be limited to electrons and protons. Examples of experimental and theoretical results in both linear and circular machines are included

  15. Spin dynamics in storage rings and linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, J. [Stanford Univ., CA (United States)

    1994-12-01

    The purpose of these lectures is to survey the subject of spin dynamics in accelerators: to give a sense of the underlying physics, the typical analytic and numeric methods used, and an overview of results achieved. Consideration will be limited to electrons and protons. Examples of experimental and theoretical results in both linear and circular machines are included.

  16. Fuzzy Control of Cold Storage Refrigeration System with Dynamic Coupling Compensation

    Directory of Open Access Journals (Sweden)

    Xiliang Ma

    2018-01-01

    Full Text Available Cold storage refrigeration systems possess the characteristics of multiple input and output and strong coupling, which brings challenges to the optimize control. To reduce the adverse effects of the coupling and improve the overall control performance of cold storage refrigeration systems, a control strategy with dynamic coupling compensation was studied. First, dynamic model of a cold storage refrigeration system was established based on the requirements of the control system. At the same time, the coupling between the components was studied. Second, to reduce the adverse effects of the coupling, a fuzzy controller with dynamic coupling compensation was designed. As for the fuzzy controller, a self-tuning fuzzy controller was served as the primary controller, and an adaptive neural network was adopted to compensate the dynamic coupling. Finally, the proposed control strategy was employed to the cold storage refrigeration system, and simulations were carried out in the condition of start-up, variable load, and variable degree of superheat, respectively. The simulation results verify the effectiveness of the fuzzy control method with dynamic coupling compensation.

  17. Experimental studies of photon-surface interaction dynamics in the alkali halides

    International Nuclear Information System (INIS)

    Haglund, R.F. Jr.; Tolk, N.H.

    1986-01-01

    We describe recent measurements which have provided, in unprecedented detail, insights into the electronic mechanisms through which energy carried into a material by photon irradiation is absorbed, localized and rechanneled to produce desorption, surface modification, erosion and damage. The specific object of these studies has been desorption induced by electronic transition in alkali halide crystals, with particular emphasis on the dynamics of changes in the surface and near-surface regions. In our experiments, the irradiating ultraviolet photons are provided by a synchrotron storage ring, and the dynamical information about desorption products is obtained from optical measurements of the quantum states, yields and velocity distributions of neutral ground-state and excited-state atoms ejected from the surface of the irradiating material. These studies have shown that the dominant exit channels in photon-induced particle emission are those producing ground-state and excited-state neutral atoms. Using dynamical information about these desorbing neutral species, obtained, for example, by laser-induced fluorescence and laser Doppler spectroscopy, we are generating an increasingly comprehensive picture of the dynamics of electronic energy flow into and out of pure crystalline surfaces in these prototypical dielectrics. We are also beginning to be able to relate desorption dynamics to specific materials properties, and to discriminate between pure surface and near-surface effects in these materials. Applications of these techniques to the problem of photon-induced surface damage and to analysis of surface dynamics in dielectric materials are discussed, and the relationships between these nearly ideal model materials and the non-crystalline, covalently bonded materials more typical of real optical elements are pointed out. 19 refs., 13 figs

  18. An analysis of the long-term stability of the particle dynamics in hadron storage rings

    International Nuclear Information System (INIS)

    Bruening, O.S.

    1994-05-01

    This thesis extends the stability analysis of the particle motion in a storage ring and estimates the diffusion rates well inside the dynamic aperture. The calculation of the drift and diffusion coefficients focuses on an application to the proton storage ring in HERA, where the proton beam lifetime drops considerably after the proton and electron beams are brought to collision. The analysis shows that the combined effect of slow and fast modulation frequencies leads to an increased emittance growth in the storage ring. HERA the slow frequency components are caused by ground motion in the HERA tunnel and the fast frequency components by ripples in the power supplies. The thesis provides upper limits for the modultion depths of a fast tune modulation which result in tolerable growth rates for the proton emittance. The analytically calculated drift coefficients agree numerical simulations for the particle dynamics. A comparison of the calculated drift coefficients with those measured in the HERA proton storage ring shows that the analyzed mechanism can lead to growth rates of the same order of magnitude as the ones measured during the luminosity operation in the HERA storage ring. Analytical estimates for the proton growth rates predict a high sensitivity to the particle diffusion on the frequency components of the fast fast tune modulation. This prediction was confirmed by a subsequent modulation experiment in the proton storage ring of HERA, where an external tune modulation with fast frequency components led to a drastic increase in the growth rates

  19. Dynamic air layer on textured superhydrophobic surfaces

    KAUST Repository

    Vakarelski, Ivan Uriev; Chan, Derek Y C; Marston, Jeremy; Thoroddsen, Sigurdur T

    2013-01-01

    -sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux

  20. Defining and measuring the mean residence time of lateral surface transient storage zones in small streams

    Science.gov (United States)

    T.R. Jackson; R. Haggerty; S.V. Apte; A. Coleman; K.J. Drost

    2012-01-01

    Surface transient storage (STS) has functional significance in stream ecosystems because it increases solute interaction with sediments. After volume, mean residence time is the most important metric of STS, but it is unclear how this can be measured accurately or related to other timescales and field-measureable parameters. We studied mean residence time of lateral...

  1. Dynamic tuning of optical absorbers for accelerated solar-thermal energy storage.

    Science.gov (United States)

    Wang, Zhongyong; Tong, Zhen; Ye, Qinxian; Hu, Hang; Nie, Xiao; Yan, Chen; Shang, Wen; Song, Chengyi; Wu, Jianbo; Wang, Jun; Bao, Hua; Tao, Peng; Deng, Tao

    2017-11-14

    Currently, solar-thermal energy storage within phase-change materials relies on adding high thermal-conductivity fillers to improve the thermal-diffusion-based charging rate, which often leads to limited enhancement of charging speed and sacrificed energy storage capacity. Here we report the exploration of a magnetically enhanced photon-transport-based charging approach, which enables the dynamic tuning of the distribution of optical absorbers dispersed within phase-change materials, to simultaneously achieve fast charging rates, large phase-change enthalpy, and high solar-thermal energy conversion efficiency. Compared with conventional thermal charging, the optical charging strategy improves the charging rate by more than 270% and triples the amount of overall stored thermal energy. This superior performance results from the distinct step-by-step photon-transport charging mechanism and the increased latent heat storage through magnetic manipulation of the dynamic distribution of optical absorbers.

  2. Evaluation of alternative phase change materials for energy storage in solar dynamic applications

    Science.gov (United States)

    Crane, R. A.; Dustin, M. O.

    1988-01-01

    The performance of fluoride salt and metallic thermal energy storage materials are compared in terms of basic performance as applied to solar dynamic power generation. Specific performance considerations include uniformity of cycle inlet temperature, peak cavity temperature, TES utilization, and system weights. Also investigated were means of enhancing the thermal conductivity of the salts and its effect on the system performance.

  3. Dynamics of water transport and storage in conifers studied with deuterium and heat tracing techniques.

    Science.gov (United States)

    F.C. Meinzer; J.R. Brooks; J.-C. Domec; B.L. Gartner; J.M. Warren; D.R. Woodruff; K. Bible; D.C. Shaw

    2006-01-01

    The volume and complexity of their vascular systems make the dynamics of tong-distance water transport in large trees difficult to study. We used heat and deuterated water (D20) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the coniferous species Pseudotsuga menziesii...

  4. A physical model to predict climate dynamics in ventilated bulk-storage of agricultural produce

    NARCIS (Netherlands)

    Lukasse, L.J.S.; Kramer-Cuppen, de J.E.; Voort, van der A.J.

    2007-01-01

    This paper presents a physical model for predicting climate dynamics in ventilated bulk-storage of agricultural produce. A well-ordered model presentation was obtained by combining an object-oriented zonal decomposition with a process-oriented decomposition through matrix¿vector notation. The

  5. Studying unsaturated epikarst water storage properties by time lapse surface to depth gravity measurements

    Science.gov (United States)

    Deville, S.; Champollion, C.; chery, J.; Doerflinger, E.; Le Moigne, N.; Bayer, R.; Vernant, P.

    2011-12-01

    The assessment of water storage in the unsaturated zone in karstic areas is particularly challenging. Indeed, water flow path and water storage occur in quite heterogeneous ways through small scale porosity, fractures, joints and large voids. Due to this large heterogeneity, it is therefore difficult to estimate the amount of water circulating in the vadose zone by hydrological means. One indirect method consists to measure the gravity variation associated to water storage and withdrawal. Here, we apply a gravimetric method in which the gravity is measured at the surface and at depth on different sites. Then the time variations of the surface to depth (STD) gravity differences are compared for each site. In this study we attempt to evaluate the magnitude of epikarstic water storage variation in various karst settings using a CG5 portable gravimeter. Surface to depth gravity measurements are performed two times a year since 2009 at the surface an inside caves at different depths on three karst aquifers in southern France : 1. A limestone site on the Larzac plateau with a vadose zone thickness of 300m On this site measurements are done on five locations at different depths going from 0 to 50 m; 2. A dolomitic site on the Larzac plateau (Durzon karst aquifer) with a vadose zone thickness of 200m; Measurements are taken at the surface and at 60m depth 3. A limestone site on the Hortus karst aquifer and "Larzac Septentrional karst aquifer") with a vadose zone thickness of only 35m. Measurements are taken at the surface and at 30m depth Therefore, our measurements are used in two ways : First, the STD differences between dry and wet seasons are used to estimate the capacity of differential storage of each aquifer. Surprisingly, the differential storage capacity of all the sites is relatively invariant despite their variable geological of hydrological contexts. Moreover, the STD gravity variations on site 1 show that no water storage variation occurs beneath 10m depth

  6. Hydrogen storage of catalyst-containing activated carbon fibers and effect of surface modification

    International Nuclear Information System (INIS)

    Ikpyo Hong; Seong Young Lee; Kyung Hee Lee; Sei Min Park

    2005-01-01

    Introduction: The hydrogen storage capacities of many kind of carbon nano materials have been reported with possibility and improbability. It is reported that specific surface area of carbon nano material has not a close relation to hydrogen storage capacity. This result shows that there is difference between specific surface area measured by isothermal nitrogen adsorption and direct measurement of adsorption with hydrogen and suggests that the carbon material with relatively low specific surface area can have high hydrogen storage capacity when they have effective nano pore. In this study, petroleum based isotropic pitch was hybridized with several kinds of transitional metal base organometallic compound solved with organic solvent and spun by electro-spinning method. The catalyst-dispersed ACFs were prepared and characterized and hydrogen storage capacity was measured. The effect of surface modification of ACFs by physical and chemical treatment was also investigated. Experimental: The isotropic precursor pitch prepared by nitrogen blowing from naphtha cracking bottom oil was hybridized with transitional metal based acetyl acetonates and spun by solvent electro-spinning. Tetrahydrofuran and quinoline were used as solvent with various mixing ratio. High voltage DC power generator which could adjust in the range of 0-60000 V and 2 mA maximum current was used to supply electrostatic force. At the solvent electro-spinning, solvent mixing ratio and pitch concentration, voltage and spinning distance were varied and their influences were investigated. The catalyst-dispersed electro-spun pitch fibers were thermal stabilized, carbonized and activated by conventional heat treatment for activated carbon fiber. Prepared fibers were observed by high resolution SEM and pore properties were characterized by Micromeritics ASAP2020 model physi-sorption analyzer. Hydrogen storage capacities were measured by equipment modified from Thermo Cahn TherMax 500 model high pressure

  7. Impact of Water Withdrawals from Groundwater and Surface Water on Continental Water Storage Variations

    Science.gov (United States)

    Doell, Petra; Hoffmann-Dobrev, Heike; Portmann, Felix T.; Siebert, Stefan; Eicker, Annette; Rodell, Matthew; Strassberg, Gil

    2011-01-01

    Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 cubic km/yr during 1998-2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 cubic km/yr during 1998-2002. It is the sum of the net abstraction of 250 cubic km/yr of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/yr of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on

  8. Electrode surface engineering by atomic layer deposition: A promising pathway toward better energy storage

    KAUST Repository

    Ahmed, Bilal

    2016-04-29

    Research on electrochemical energy storage devices including Li ion batteries (LIBs), Na ion batteries (NIBs) and supercapacitors (SCs) has accelerated in recent years, in part because developments in nanomaterials are making it possible to achieve high capacities and energy and power densities. These developments can extend battery life in portable devices, and open new markets such as electric vehicles and large-scale grid energy storage. It is well known that surface reactions largely determine the performance and stability of electrochemical energy storage devices. Despite showing impressive capacities and high energy and power densities, many of the new nanostructured electrode materials suffer from limited lifetime due to severe electrode interaction with electrolytes or due to large volume changes. Hence control of the surface of the electrode material is essential for both increasing capacity and improving cyclic stability of the energy storage devices.Atomic layer deposition (ALD) which has become a pervasive synthesis method in the microelectronics industry, has recently emerged as a promising process for electrochemical energy storage. ALD boasts excellent conformality, atomic scale thickness control, and uniformity over large areas. Since ALD is based on self-limiting surface reactions, complex shapes and nanostructures can be coated with excellent uniformity, and most processes can be done below 200. °C. In this article, we review recent studies on the use of ALD coatings to improve the performance of electrochemical energy storage devices, with particular emphasis on the studies that have provided mechanistic insight into the role of ALD in improving device performance. © 2016 Elsevier Ltd.

  9. Near-surface storage facilities for vitrified high-level wastes

    International Nuclear Information System (INIS)

    Kondrat'ev, A.N.; Kulichenko, V.V.; Kryukov, I.I.; Krylova, N.V.; Paramoshkin, V.I.; Strakhov, M.V.

    1980-01-01

    Concurrently with the development of methods for solidifying liquid radioactive wastes, reliable and safe methods for the storage and disposal of solidified wastes are being devised in the USSR and other countries. One of the main factors affecting the choice of storage conditions for solidified wastes originating from the vitrification of high-level liquid wastes from fuel reprocessing plants is the problem of removing the heat produced by radioactive decay. In order to prevent the temperature of solidified wastes from exceeding the maximum permissible level for the material concerned, it is necessary to limit either the capacity of waste containers or the specific heat release of the wastes themselves. In order that disposal of high-level wastes in geological formations should be reliable and economic, solidified wastes undergo interim storage in near-surface storage facilities with engineered cooling systems. The paper demonstrates the relative influences of specific heat release, of the maximum permissible storage temperature for vitrified wastes and of the methods chosen for cooling wastes in order for the dimensions of waste containers to be reduced to the extent required. The effect of concentrating wastes to a given level in the vitrification process on the cost of storage in different types of storage facility is also examined. Calculations were performed for the amount of vitrified wastes produced by a reprocessing plant with a capacity of five tonnes of uranium per 24 hours. Fuel elements from reactors of the water-cooled, water-moderated type are sent for reprocessing after having been held for about two years. The dimensions of the storage facility are calculated on the assumption that it will take five years to fill

  10. Surface contamination of hazardous drug pharmacy storage bins and pharmacy distributor shipping containers.

    Science.gov (United States)

    Redic, Kimberly A; Fang, Kayleen; Christen, Catherine; Chaffee, Bruce W

    2018-03-01

    Purpose This study was conducted to determine whether there is contamination on exterior drug packaging using shipping totes from the distributor and carousel storage bins as surrogate markers of external packaging contamination. Methods A two-part study was conducted to measure the presence of 5-fluorouracil, ifosfamide, cyclophosphamide, docetaxel and paclitaxel using surrogate markers for external drug packaging. In Part I, 10 drug distributor shipping totes designated for transport of hazardous drugs provided a snapshot view of contamination from regular use and transit in and out of the pharmacy. An additional two totes designated for transport of non-hazardous drugs served as controls. In Part II, old carousel storage bins (i.e. those in use pre-study) were wiped for snapshot view of hazardous drug contamination on storage bins. New carousel storage bins were then put into use for storage of the five tested drugs and used for routine storage and inventory maintenance activities. Carousel bins were wiped at time intervals 0, 8, 16 and 52 weeks to measure surface contamination. Results Two of the 10 hazardous shipping totes were contaminated. Three of the five-old carousel bins were contaminated with cyclophosphamide. One of the old carousel bins was also contaminated with ifosfamide. There were no detectable levels of hazardous drugs on any of the new storage bins at time 0, 8 or 16 weeks. However, at the Week 52, there was a detectable level of 5-FU present in the 5-FU carousel bin. Conclusions Contamination of the surrogate markers suggests that external packaging for hazardous drugs is contaminated, either during the manufacturing process or during routine chain of custody activities. These results demonstrate that occupational exposure may occur due to contamination from shipping totes and storage bins, and that handling practices including use of personal protective equipment is warranted.

  11. Surface Modification of MXenes: A Pathway to Improve MXene Electrode Performance in Electrochemical Energy Storage Devices

    KAUST Repository

    Ahmed, Bilal

    2017-12-31

    The recent discovery of layered transition metal carbides (MXenes) is one of the most important developments in two-dimensional (2D) materials. Preliminary theoretical and experimental studies suggest a wide range of potential applications for MXenes. The MXenes are prepared by chemically etching ‘A’-layer element from layered ternary metal carbides, nitrides and carbonitrides (MAX phases) through aqueous acid treatment, which results in various surface terminations such as hydroxyl, oxygen or fluorine. It has been found that surface terminations play a critical role in defining MXene properties and affects MXene performance in different applications such as electrochemical energy storage, electromagnetic interference shielding, water purification, sensors and catalysis. Also, the electronic, thermoelectric, structural, plasmonic and optical properties of MXenes largely depend upon surface terminations. Thus, controlling the surface chemistry if MXenes can be an efficient way to improve their properties. This research mainly aims to perform surface modifications of two commonly studied MXenes; Ti2C and Ti3C2, via chemical, thermal or physical processes to enhance electrochemical energy storage properties. The as-prepared and surface modified MXenes have been studied as electrode materials in Li-ion batteries (LIBs) and supercapacitors (SCs). In pursuit of desirable MXene surface, we have developed an in-situ room temperature oxidation process, which resulted in TiO2/MXene nanocomposite and enhanced Li-ion storage. The idea of making metal oxide and MXene nanocomposites was taken to the next level by combining a high capacity anode materials – SnO2 – and MXene. By taking advantage of already existing surface functional groups (–OH), we have developed a composite of SnO2/MXene by atomic layer deposition (ALD) which showed enhanced capacity and excellent cyclic stability. Thermal annealing of MXene at elevated temperature under different atmospheres was

  12. Nanoporous Ni with High Surface Area for Potential Hydrogen Storage Application.

    Science.gov (United States)

    Zhou, Xiaocao; Zhao, Haibo; Fu, Zhibing; Qu, Jing; Zhong, Minglong; Yang, Xi; Yi, Yong; Wang, Chaoyang

    2018-06-01

    Nanoporous metals with considerable specific surface areas and hierarchical pore structures exhibit promising applications in the field of hydrogen storage, electrocatalysis, and fuel cells. In this manuscript, a facile method is demonstrated for fabricating nanoporous Ni with a high surface area by using SiO₂ aerogel as a template, i.e., electroless plating of Ni into an SiO₂ aerogel template followed by removal of the template at moderate conditions. The effects of the prepared conditions, including the electroless plating time, temperature of the structure, and the magnetism of nanoporous Ni are investigated in detail. The resultant optimum nanoporous Ni with a special 3D flower-like structure exhibited a high specific surface area of about 120.5 m²/g. The special nanoporous Ni exhibited a promising prospect in the field of hydrogen storage, with a hydrogen capacity of 0.45 wt % on 4.5 MPa at room temperature.

  13. Nonlinear dynamics in the perceptual grouping of connected surfaces.

    Science.gov (United States)

    Hock, Howard S; Schöner, Gregor

    2016-09-01

    Evidence obtained using the dynamic grouping method has shown that the grouping of an object's connected surfaces has properties characteristic of a nonlinear dynamical system. When a surface's luminance changes, one of its boundaries is perceived moving across the surface. The direction of this dynamic grouping (DG) motion indicates which of two flanking surfaces has been grouped with the changing surface. A quantitative measure of overall grouping strength (affinity) for adjacent surfaces is provided by the frequency of DG motion perception in directions promoted by the grouping variables. It was found that: (1) variables affecting surface grouping for three-surface objects evolve over time, settling at stable levels within a single fixation, (2) how often DG motion is perceived when a surface's luminance is perturbed (changed) depends on the pre-perturbation affinity state of the surface grouping, (3) grouping variables promoting the same surface grouping combine cooperatively and nonlinearly (super-additively) in determining the surface grouping's affinity, (4) different DG motion directions during different trials indicate that surface grouping can be bistable, which implies that inhibitory interactions have stabilized one of two alternative surface groupings, and (5) when alternative surface groupings have identical affinity, stochastic fluctuations can break the symmetry and inhibitory interactions can then stabilize one of the surface groupings, providing affinity levels are not too high (which results in bidirectional DG motion). A surface-grouping network is proposed within which boundaries vary in salience. Low salience or suppressed boundaries instantiate surface grouping, and DG motion results from changes in boundary salience. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Effect of surface modification and hybridization on dynamic ...

    Indian Academy of Sciences (India)

    Epoxy; Roystonea regia; glass; surface modification; hybridization; dynamic mechanical ... other advantages such as light weight, low cost, high specific ... ful technique to study the mechanical behaviour of mate- ... The test reveals response.

  15. The ising model on the dynamical triangulated random surface

    International Nuclear Information System (INIS)

    Aleinov, I.D.; Migelal, A.A.; Zmushkow, U.V.

    1990-01-01

    The critical properties of Ising model on the dynamical triangulated random surface embedded in D-dimensional Euclidean space are investigated. The strong coupling expansion method is used. The transition to thermodynamical limit is performed by means of continuous fractions

  16. Proposal of a relationship between dynamic aperture adn intensity evolution in a storage ring

    CERN Document Server

    Giovannozzi, M

    2010-01-01

    A scaling law for the time-dependence of the dynamic aperture, i.e., the region of phase space where stable motion occurs, was proposed in previous papers, about ten years ago. The use of fundamental theorems of the theory of dynamical systems allowed showing that the dynamic aperture has a logarithmic dependence on time. In this paper this result, proved by mean of numerical simulations, is used as a basis for deriving a scaling law for the intensity evolution in a storage ring. The proposed scaling law is also tested against experimental data showing a remarkable agreement.

  17. Hydrological analysis relevant to surface water storage at Jabiluka. Supervising Scientist report 142

    International Nuclear Information System (INIS)

    Chiew, F.H.S.; Wang, Q.J.

    1999-01-01

    The report is prepared for the Supervising Scientist at Jabiru. It describes part of an investigation into hydrological issues relating to the water management system proposed for the Jabiluka project. Specifically, the objective is to estimate the water storage capacity required to store surface runoff and other water within the total containment zone (TCZ) of the Jabiluka project. The water storage volume is calculated for a range of probabilities up to 0.002% that the pond design volume would be exceeded over a 30-year mine life. In this study, 50 000 sets of 30 years of daily rainfall and monthly pan evaporation data are stochastically generated to simulate the storage water balance. The approach used by Kinhill and Energy Resources of Australia (ERA) is reviewed and the pond design compared with the estimates derived here. The Kinhill-ERA approach is described in the Jabiluka Mill Alternative Public Environment Report and the Jabiluka Mill Alternative Public Environment Report Technical Appendices (hereon referred to as Jabiluka PER Appendices) (1998). The two reports also provide background to many other issues. The structural design of the storage and other features of the mine site are not considered here. This study also assumes that the bunds and other drainage diversion structures will prevent all water outside the TCZ from entering the TCZ and vice versa. The storage water balance components are discussed in section 2. Some of the water inflows into the storage and losses from the storage are discussed in detail, while elsewhere, the values used by Kinhill-ERA are adopted. Section 3 describes the selection of the climate stations used here, the rainfall and pan evaporation characteristics in the area and the stochastic generation of 1.5 million years of daily rainfall and monthly pan evaporation data. Section 4 describes the approach used to estimate the storage capacity, and presents the storage capacity estimates for various probabilities of

  18. Electron cloud dynamics in the Cornell Electron Storage Ring Test Accelerator wiggler

    Directory of Open Access Journals (Sweden)

    C. M. Celata

    2011-04-01

    Full Text Available The interference of stray electrons (also called “electron clouds” with accelerator beams is important in modern intense-beam accelerators, especially those with beams of positive charge. In magnetic wigglers, used, for instance, for transverse emittance damping, the intense synchrotron radiation produced by the beam can generate an electron cloud of relatively high density. In this paper the complicated dynamics of electron clouds in wigglers is examined using the example of a wiggler in the Cornell Electron Storage Ring Test Accelerator experiment at the Cornell Electron Storage Ring. Three-dimensional particle-in-cell simulations with the WARP-POSINST computer code show different density and dynamics for the electron cloud at locations near the maxima of the vertical wiggler field when compared to locations near the minima. Dynamics in these regions, the electron cloud distribution vs longitudinal position, and the beam coherent tune shift caused by the wiggler electron cloud will be discussed.

  19. Methods and energy storage devices utilizing electrolytes having surface-smoothing additives

    Science.gov (United States)

    Xu, Wu; Zhang, Jiguang; Graff, Gordon L; Chen, Xilin; Ding, Fei

    2015-11-12

    Electrodeposition and energy storage devices utilizing an electrolyte having a surface-smoothing additive can result in self-healing, instead of self-amplification, of initial protuberant tips that give rise to roughness and/or dendrite formation on the substrate and anode surface. For electrodeposition of a first metal (M1) on a substrate or anode from one or more cations of M1 in an electrolyte solution, the electrolyte solution is characterized by a surface-smoothing additive containing cations of a second metal (M2), wherein cations of M2 have an effective electrochemical reduction potential in the solution lower than that of the cations of M1.

  20. A Dynamic Momentum Compaction Factor Lattice for Improvements to Stochastic Cooling in Storage Rings

    Energy Technology Data Exchange (ETDEWEB)

    Olivieri, David Nicholas [Massachusetts U., Amherst

    1996-01-01

    A dynamic momentum compaction factor, also referred to as a dynamic $\\Delta \\gamma \\tau$, lattice for the FNAL Antiproton Source Debuncher Storage Ring is studied, both theoretically and experimentally, for the purpose of improving stochastic precooling, and hence, improving the global antiproton production and stacking performance. A dynamic $\\Delta \\gamma \\tau$ lattice is proposed due to the competing requirements inherent within the Debuncher storage ring upon $\\gamma \\tau$· Specifically, the Debuncher storage ring performs two disparate functions, $(i)$ accepting and debunching a large number of $\\overline{p}$s/pulse at the outset of the production cycle, which would perform ideally with a large value of $\\gamma\\tau$, and $(ii)$ subsequently employing stochastic cooling throughout the remainder of the $\\overline{p}$ production cycle for improved transfer and stacking efficiency into the Accumulator, for which a small value $\\gamma \\tau$ is ideal in order to reduce the diffusive heating caused by the mixing factor. In the initial design of the Debuncher optical lattice, an intermediate value of $\\gamma \\tau$ was chosen as a compromise between the two functional requirements. The goal of the thesis is to improve stochastic precooling by changing $\\gamma \\tau$ between two desired values during each p production cycle. In particular, the dynamic $\\Delta \\gamma \\tau$ lattice accomplishes a reduction in $\\gamma \\tau$, and hence the mixing factor, through an uniform increase to the dispersion throughout the arc sections of the storage ring. Experimental measurements of cooling rates and system performance parameters, with the implementation of the dynamic $\\Delta \\gamma \\tau$ lattice, are in agreement with theoretical predictions based upon a detailed integration of the stochastic cooling Fokker Planck equations. Based upon the consistency between theory and experiment, predictions of cooling rates are presented for future operational

  1. Dynamics of electrons and holes at surfaces

    International Nuclear Information System (INIS)

    Chulkov, E.V.; Leonardo, A.; Sklyadneva, I.Yu.; Silkin, V.M.

    2007-01-01

    We present ab initio calculation results for electron-phonon (e-ph) contribution to hole lifetime broadening of the X-bar surface state on Al(0 0 1). We show that e-ph coupling in this state is significantly stronger than in bulk Al at the Fermi level. It makes the e-ph decay channel very important in the formation of the hole decay in the surface state at X-bar. We also present the results for e-e lifetime broadening in a quantum-well state in 1 ML K/Cu(1 1 1). We show that this contribution is not negligible and is much larger than that in a surface state on Ag(1 1 1)

  2. Demand for seasonal gas storage in northwest Europe until 2030. Simulation results with a dynamic model

    International Nuclear Information System (INIS)

    De Joode, J.; Oezdemir, Oe.

    2010-01-01

    The fact that depletion of indigenous gas production increases gas import dependency is widely known and accepted. However, there is considerable less attention for the implications of indigenous resource depletion for the provision of seasonal flexibility. The traditionally largest source of seasonal flexibility in Europe is indigenous gas production, mainly based in the Netherlands and the United Kingdom. With the depletion of indigenous sources the market increasingly needs to rely on other sources for seasonal flexibility, such as gas storage facilities. We investigate the future need for gas storage as a source for seasonal flexibility provision using a dynamic gas market model (GASTALE) in which different potential sources for seasonal flexibility - gas production, imports via pipeline, LNG imports and storage facilities - compete with each other in a market-based environment. The inclusion of seasonal flexibility properties in a gas market model allows a more complex analysis of seasonal flexibility issues than previously documented in literature. This is demonstrated in an analysis of the future demand for gas storage in northwestern Europe until 2030. Our results indicate that there is substantial need for additional gas storage facilities and thus supports current project proposals for new investment in gas storage facilities. (author)

  3. Ice Storage Air-Conditioning System Simulation with Dynamic Electricity Pricing: A Demand Response Study

    Directory of Open Access Journals (Sweden)

    Chi-Chun Lo

    2016-02-01

    Full Text Available This paper presents an optimal dispatch model of an ice storage air-conditioning system for participants to quickly and accurately perform energy saving and demand response, and to avoid the over contact with electricity price peak. The schedule planning for an ice storage air-conditioning system of demand response is mainly to transfer energy consumption from the peak load to the partial-peak or off-peak load. Least Squares Regression (LSR is used to obtain the polynomial function for the cooling capacity and the cost of power consumption with a real ice storage air-conditioning system. Based on the dynamic electricity pricing, the requirements of cooling loads, and all technical constraints, the dispatch model of the ice-storage air-conditioning system is formulated to minimize the operation cost. The Improved Ripple Bee Swarm Optimization (IRBSO algorithm is proposed to solve the dispatch model of the ice storage air-conditioning system in a daily schedule on summer. Simulation results indicate that reasonable solutions provide a practical and flexible framework allowing the demand response of ice storage air-conditioning systems to demonstrate the optimization of its energy savings and operational efficiency and offering greater energy efficiency.

  4. Dynamic characteristics of a flywheel energy storage system using superconducting magnetic bearings

    CERN Document Server

    Kim, J S

    2003-01-01

    The high-temperature superconducting magnetic bearing flywheel energy storage system (SMB-FESS) is proposed as an efficient energy storage system. It is important to identify the dynamic behaviour and the characteristics of the SMB-FESS. First, a new method for identifying SMB characteristics has been suggested. The suggested modelling method is verified by comparing the experimental and analytical frequency response functions. In this study, the analyses of critical speed and unbalance response are performed using the analytical model. The experimental test has been carried out to verify the result of simulation. A good agreement has been observed between the experiment and the simulation result.

  5. Latent energy storage with salt and metal mixtures for solar dynamic applications

    Science.gov (United States)

    Crane, R. A.; Konstantinou, K. S.

    1988-01-01

    This paper examines three design alternatives for the development of a solar dynamic heat receiver as applied to power systems operating in low earth orbit. These include a base line design used for comparison in ongoing NASA studies, a system incorporating a salt energy storage system with the salt dispersed within a metal mesh and a hybrid system incorporating both a molten salt and molten metal for energy storage. Based on a typical low earth orbit condition, designs are developed and compared to determine the effect of resultant conductivity, heat capacity and heat of fusion on system size, weight, temperature gradients, cycle turbine inlet temperature and material utilization.

  6. Experimental Testing Procedures and Dynamic Model Validation for Vanadium Redox Flow Battery Storage System

    DEFF Research Database (Denmark)

    Baccino, Francesco; Marinelli, Mattia; Nørgård, Per Bromand

    2013-01-01

    The paper aims at characterizing the electrochemical and thermal parameters of a 15 kW/320 kWh vanadium redox flow battery (VRB) installed in the SYSLAB test facility of the DTU Risø Campus and experimentally validating the proposed dynamic model realized in Matlab-Simulink. The adopted testing...... efficiency of the battery system. The test procedure has general validity and could also be used for other storage technologies. The storage model proposed and described is suitable for electrical studies and can represent a general model in terms of validity. Finally, the model simulation outputs...

  7. Long term, non-anthropogenic groundwater storage changes simulated by a global land surface model

    Science.gov (United States)

    Li, B.; Rodell, M.; Sheffield, J.; Wood, E. F.

    2017-12-01

    Groundwater is crucial for meeting agricultural, industrial and municipal water needs, especially in arid, semi-arid and drought impacted regions. Yet, knowledge on groundwater response to climate variability is not well understood due to lack of systematic and continuous in situ measurements. In this study, we investigate global non-anthropogenic groundwater storage variations with a land surface model driven by a 67-year (1948-204) meteorological forcing data set. Model estimates were evaluated using in situ groundwater data from the central and northeastern U.S. and terrestrial water storage derived from the Gravity Recovery and Climate Experiment (GRACE) satellites and found to be reasonable. Empirical orthogonal function (EOF) analysis was employed to examine modes of variability of groundwater storage and their relationship with atmospheric effects such as precipitation and evapotranspiration. The result shows that the leading mode in global groundwater storage reflects the influence of the El Niño Southern Oscillation (ENSO). Consistent with the EOF analysis, global total groundwater storage reflected the low frequency variability of ENSO and decreased significantly over 1948-2014 while global ET and precipitation did not exhibit statistically significant trends. This study suggests that while precipitation and ET are the primary drivers of climate related groundwater variability, changes in other forcing fields than precipitation and temperature are also important because of their influence on ET. We discuss the need to improve model physics and to continuously validate model estimates and forcing data for future studies.

  8. Dynamic surface properties of poly(methylalkyldiallylammonium chloride) solutions

    Czech Academy of Sciences Publication Activity Database

    Novikova, A. A.; Vlasov, P. S.; Lin, S.-Y.; Sedláková, Zdeňka; Noskov, B. A.

    2017-01-01

    Roč. 80, November (2017), s. 122-127 ISSN 1876-1070 Institutional support: RVO:61389013 Keywords : polymer solutions * dynamic surface tension * dilational surface rheology Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 4.217, year: 2016

  9. The Dynamics and Structures of Adsorbed Surfaces

    DEFF Research Database (Denmark)

    Nielsen, M; Ellenson, W. D.; McTague, J. P.

    1978-01-01

    . Elastic neutron diffraction measurements, determining the two-dimensional structural ordering of the adsorbed films, have been performed on layers of N2, Ar, H2, D2, O2, Kr, and He. Measurements on layers of larger molecules such as CD4 and ND3 have also been reported. Inelastic neutron scattering...... measurements, studying the dynamics of the adsorbed films are only possible in a few especially favourable cases such as 36Ar and D2 films, where the coherent phonon scattering cross-sections are very large. In other cases incoherent scattering from hydrogen can give information about e.g. the mobility...

  10. Bulk water freezing dynamics on superhydrophobic surfaces

    Science.gov (United States)

    Chavan, S.; Carpenter, J.; Nallapaneni, M.; Chen, J. Y.; Miljkovic, N.

    2017-01-01

    In this study, we elucidate the mechanisms governing the heat-transfer mediated, non-thermodynamic limited, freezing delay on non-wetting surfaces for a variety of characteristic length scales, Lc (volume/surface area, 3 mm commercial superhydrophobic spray coatings, showing a monotonic increase in freezing time with coating thickness. The added thermal resistance of thicker coatings was much larger than that of the nanoscale superhydrophobic features, which reduced the droplet heat transfer and increased the total freezing time. Transient finite element method heat transfer simulations of the water slab freezing process were performed to calculate the overall heat transfer coefficient at the substrate-water/ice interface during freezing, and shown to be in the range of 1-2.5 kW/m2K for these experiments. The results shown here suggest that in order to exploit the heat-transfer mediated freezing delay, thicker superhydrophobic coatings must be deposited on the surface, where the coating resistance is comparable to the bulk water/ice conduction resistance.

  11. Following the surface response of caffeine cocrystals to controlled humidity storage by atomic force microscopy.

    Science.gov (United States)

    Cassidy, A M C; Gardner, C E; Jones, W

    2009-09-08

    Active pharmaceutical ingredient (API) stability in solid state tablet formulation is frequently a function of the relative humidity (RH) environment in which the drug is stored. Caffeine is one such problematic API. Previously reported caffeine cocrystals, however, were found to offer increased resistance to caffeine hydrate formation. Here we report on the use of atomic force microscopy (AFM) to image the surface of two caffeine cocrystal systems to look for differences between the surface and bulk response of the cocrystal to storage in controlled humidity environments. Bulk responses have previously been assessed by powder X-ray diffraction. With AFM, pinning sites were identified at step edges on caffeine/oxalic acid, with these sites leading to non-uniform step movement on going from ambient to 0% RH. At RH >75%, areas of fresh crystal growth were seen on the cocrystal surface. In the case of caffeine/malonic acid the cocrystals were observed to absorb water anisotropically after storage at 75% RH for 2 days, affecting the surface topography of the cocrystal. These results show that AFM expands on the data gathered by bulk analytical techniques, such as powder X-ray diffraction, by providing localised surface information. This surface information may be important for better predicting API stability in isolation and at a solid state API-excipient interface.

  12. Dynamic interactions of Leidenfrost droplets on liquid metal surface

    Science.gov (United States)

    Ding, Yujie; Liu, Jing

    2016-09-01

    Leidenfrost dynamic interaction effects of the isopentane droplets on the surface of heated liquid metal were disclosed. Unlike conventional rigid metal, such conductive and deformable liquid metal surface enables the levitating droplets to demonstrate rather abundant and complex dynamics. The Leidenfrost droplets at different diameters present diverse morphologies and behaviors like rotation and oscillation. Depending on the distance between the evaporating droplets, they attract and repulse each other through the curved surfaces beneath them and their vapor flows. With high boiling point up to 2000 °C, liquid metal offers a unique platform for testing the evaporating properties of a wide variety of liquid even solid.

  13. Parametric Study on the Dynamic Heat Storage Capacity of Building Elements

    DEFF Research Database (Denmark)

    Artmann, Nikolai; Manz, H.; Heiselberg, Per

    2007-01-01

    as their interrelation. The potential of increasing thermal mass by using phase change materials (PCM) was estimated assuming increased thermal capacity. The results show a significant impact of the heat transfer coefficient on heat storage capacity, especially for thick, thermally heavy elements. The storage capacity...... of onedimensional heat conduction in a slab with convective boundary condition was applied to quantify the dynamic heat storage capacity of a particular building element. The impact of different parameters, such as slab thickness, material properties and the heat transfer coefficient was investigated, as well......In modern, extensively glazed office buildings, due to high solar and internal loads and increased comfort expectations, air conditioning systems are often used even in moderate and cold climates. Particularly in this case, passive cooling by night-time ventilation seems to offer considerable...

  14. A Method of Dynamic Extended Reactive Power Optimization in Distribution Network Containing Photovoltaic-Storage System

    Science.gov (United States)

    Wang, Wu; Huang, Wei; Zhang, Yongjun

    2018-03-01

    The grid-integration of Photovoltaic-Storage System brings some undefined factors to the network. In order to make full use of the adjusting ability of Photovoltaic-Storage System (PSS), this paper puts forward a reactive power optimization model, which are used to construct the objective function based on power loss and the device adjusting cost, including energy storage adjusting cost. By using Cataclysmic Genetic Algorithm to solve this optimization problem, and comparing with other optimization method, the result proved that: the method of dynamic extended reactive power optimization this article puts forward, can enhance the effect of reactive power optimization, including reducing power loss and device adjusting cost, meanwhile, it gives consideration to the safety of voltage.

  15. Analytical study of dynamic aperture for storage ring by using successive linearization method

    International Nuclear Information System (INIS)

    Yang Jiancheng; Xia Jiawen; Wu Junxia; Xia Guoxing; Liu Wei; Yin Xuejun

    2004-01-01

    The determination of dynamic aperture is a critical issue in circular accelerator. In this paper, authors solved the equation of motion including non-linear forces by using successive linearization method and got a criterion for the determining of the dynamic aperture of the machine. Applying this criterion, a storage ring with FODO lattice has been studied. The results are agree well with the tracking results in a large range of linear turn (Q). The purpose is to improve our understanding of the mechanisms driving the particle motion in the presence of non-linear forces and got another mechanism driving instability of particle in storage ring-parametric resonance caused by 'fluctuating transfer matrices' at small amplification

  16. Dynamic stability of passive dynamic walking on an irregular surface.

    Science.gov (United States)

    Su, Jimmy Li-Shin; Dingwell, Jonathan B

    2007-12-01

    Falls that occur during walking are a significant health problem. One of the greatest impediments to solve this problem is that there is no single obviously "correct" way to quantify walking stability. While many people use variability as a proxy for stability, measures of variability do not quantify how the locomotor system responds to perturbations. The purpose of this study was to determine how changes in walking surface variability affect changes in both locomotor variability and stability. We modified an irreducibly simple model of walking to apply random perturbations that simulated walking over an irregular surface. Because the model's global basin of attraction remained fixed, increasing the amplitude of the applied perturbations directly increased the risk of falling in the model. We generated ten simulations of 300 consecutive strides of walking at each of six perturbation amplitudes ranging from zero (i.e., a smooth continuous surface) up to the maximum level the model could tolerate without falling over. Orbital stability defines how a system responds to small (i.e., "local") perturbations from one cycle to the next and was quantified by calculating the maximum Floquet multipliers for the model. Local stability defines how a system responds to similar perturbations in real time and was quantified by calculating short-term and long-term local exponential rates of divergence for the model. As perturbation amplitudes increased, no changes were seen in orbital stability (r(2)=2.43%; p=0.280) or long-term local instability (r(2)=1.0%; p=0.441). These measures essentially reflected the fact that the model never actually "fell" during any of our simulations. Conversely, the variability of the walker's kinematics increased exponentially (r(2)>or=99.6%; psimulated conditions, the walker remained orbitally stable, while exhibiting substantial local instability. This was because very small initial perturbations diverged away from the limit cycle, while larger

  17. Bursts of Coherent Synchrotron Radiation in Electron Storage Rings: a Dynamical Model

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, Marco

    2002-09-17

    Evidence of coherent synchrotron radiation (CSR) has been reported recently at the electron storage rings of several light source facilities. The main features of the observations are (i) a radiation wavelength short compared to the nominal bunch length, and (ii) a coherent signal showing recurrent bursts of duration much shorter than the radiation damping time, but with spacing equal to a substantial fraction of the damping time. We present a model of beam longitudinal dynamics that reproduces these features.

  18. Dynamical aspects on FEL interaction in single passage and storage ring devices

    Energy Technology Data Exchange (ETDEWEB)

    Dattoli, G.; Renieri, A. [ENEA, Frascati (Italy)

    1995-12-31

    The dynamical behaviour of the free-electron lasers is investigated using appropriate scaling relations valid for devices operating in the low and high gain regimes, including saturation. The analysis is applied to both single passage and storage ring configurations. In the latter case the interplay between the interaction of the electron bean with the laser field and with the accelerator environment is investigated. In particular we discuss the effect of FEL interaction on the microwave instability.

  19. Materials compatibility issues related to thermal energy storage for a space solar dynamic power system

    Science.gov (United States)

    Faget, N. M.

    1986-01-01

    Attention is given to results obtained to date in developmental investigations of a thermal energy storage (TES) system for the projected NASA Space Station's solar dynamic power system; these tests have concentrated on issues related to materials compatibility for phase change materials (PCMs) and their containment vessels' materials. The five PCMs tested have melting temperatures that correspond to the operating temperatures of either the Brayton or Rankine heat engines, which were independently chosen for their high energy densities.

  20. Excess Li-Ion Storage on Reconstructed Surfaces of Nanocrystals To Boost Battery Performance

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yandong; Zhang, Bingkai; Zheng, Jiaxin; Hu, Jiangtao; Wen, Jianguo; Miller, Dean; Yan, Pengfei; Liu, Tongchao; Guo, Hua; Li, Wen; Song, Xiaohe; Zhou, Zengquing; Liu, Chaokun; Tang, Hanting; Tan, Rui; Chen, Zonghai; Ren, Yang; Lin, Yuan; Yang, Wanli; Wang, Chongmin; Wang, Lin-Wang; Lu, Jun; Amine, Khalil; Pan, Feng

    2017-08-03

    Abstract. Due to the enhanced kinetic properties, nanocrystallites have received much attention as potential electrode materials for energy storage. However, because of the large specific surface areas of nanocrystallites, they usually suffer from decreased energy density, reduced cycling stability and total electrode capacity. In this work, we report a size-dependent excess capacity beyond the theoretical value of 170 mAhg-1 in a special carbon coated LiFePO4 composite cathode material, which delivers capacities of 191.2 and 213.5 mAhg-1 with the mean particle sizes of 83 nm and 42 nm, respectively. Moreover, this LiFePO4 composite also shows excellent cycling stability and high rate performance. Our further experimental tests and ab initio calculations reveal that the excess capacity comes from the charge passivation for which the C-O-Fe bonds would lead to charge redistribution on the surface of LiFePO4 and hence to enhance the bonding interaction between surface O atoms and Li-ions. The surface reconstruction for excess Li-ion storage makes full use of the large specific surface area for the nanocrystallites, which can maintain the fast Li-ion transport and enhance the capacity greatly that the nanocrystallites usually suffers.

  1. Numerical simulation of particle dynamics in storage rings using BETACOOL program

    International Nuclear Information System (INIS)

    Meshkov, I.N.; Pivin, R.V.; Sidorin, A.O.; Smirnov, A.V.; Trubnikov, G.V.

    2006-01-01

    BETACOOL program developed by JINR electron cooling group is a kit of algorithms based on common format of input and output files. The program is oriented to simulation of the ion beam dynamics in a storage ring in the presence of cooling and heating effects. The version presented in this report includes three basic algorithms: simulation of rms parameters of the ion distribution function evolution in time, simulation of the distribution function evolution using Monte-Carlo method and tracking algorithm based on molecular dynamics technique. General processes to be investigated with the program are intrabeam scattering in the ion beam, electron cooling, interaction with residual gas and internal target

  2. Dynamic modelling of an adsorption storage tank using a hybrid approach combining computational fluid dynamics and process simulation

    Science.gov (United States)

    Mota, J.P.B.; Esteves, I.A.A.C.; Rostam-Abadi, M.

    2004-01-01

    A computational fluid dynamics (CFD) software package has been coupled with the dynamic process simulator of an adsorption storage tank for methane fuelled vehicles. The two solvers run as independent processes and handle non-overlapping portions of the computational domain. The codes exchange data on the boundary interface of the two domains to ensure continuity of the solution and of its gradient. A software interface was developed to dynamically suspend and activate each process as necessary, and be responsible for data exchange and process synchronization. This hybrid computational tool has been successfully employed to accurately simulate the discharge of a new tank design and evaluate its performance. The case study presented here shows that CFD and process simulation are highly complementary computational tools, and that there are clear benefits to be gained from a close integration of the two. ?? 2004 Elsevier Ltd. All rights reserved.

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    It has been shown previously that surface acoustic waves can be efficiently trapped and slowed by steep ridges on a piezoelectric substrate, giving rise to two families of shear-horizontal and vertically polarized surface waves. The mechanisms of energy storage and dispersion are explored by using...... the finite element method to model surface acoustic waves generated by high aspect ratio electrodes. A periodic model is proposed including a perfectly matched layer to simulate radiation conditions away from the sources, from which the modal distributions are found. The ratio of the mechanical energy...... confined to the electrode as compared to the total mechanical energy is calculated and is found to be increasing for increasing aspect ratio and to tend to a definite limit for the two families of surface waves. This observation is in support of the interpretation that high aspect ratio electrodes act...

  4. Dynamic analysis of liquid storage tank including hydrodynamic interaction by boundary element method

    International Nuclear Information System (INIS)

    Hwang, I.T.; Ting, K.

    1987-01-01

    Dynamic response of liquid storage tanks considering the hydrodynamic interactions due to earthquake ground motion has been extensively studied. Several finite element procedures, such as Balendra et. al. (1982) and Haroun (1983), have been devoted to investigate the dynamic interaction between the deformable wall of the tank and the liquid. Further, if the geometry of the storage tank can not be described by axi-symmetric case, the tank wall and the fluid domain must be discretized by three dimensional finite elements to investigate the fluid-structure-interactions. Thus, the need of large computer memory and expense of vast computer time usually make this analysis impractical. To demonstrate the accuracy and reliability of the solution technique developed herein, the dynamic behavior of ground-supported, deformed, cylindrical tank with incompressible fluid conducted by Haroun (1983) are analyzed. Good correlations of hydrodynamic pressure distribution between the computed results with the referenced solutions are noted. The fluid compressibility significantly affects the hydrodynamic pressures of the liquid-tank-interactions and the work which is done on this discussion is still little attention. Thus, the influences of the compressibility of the liquid on the reponse of the liquid storage due to ground motion are then drawn. By the way, the complex-valued frequency response functions for hydrodynamic forces of Haroun's problem are also displayed. (orig./GL)

  5. Surface chemical state of Ti powders and its alloys: Effect of storage conditions and alloy composition

    Energy Technology Data Exchange (ETDEWEB)

    Hryha, Eduard, E-mail: hryha@chalmers.se [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE - 412 96 Gothenburg (Sweden); Shvab, Ruslan [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE - 412 96 Gothenburg (Sweden); Bram, Martin; Bitzer, Martin [Forschungszentrum Jülich GmbH, Institute of Energy and Climate Research, Materials Synthesis and Processing (IEK-1), D-52425 Jülich (Germany); Nyborg, Lars [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE - 412 96 Gothenburg (Sweden)

    2016-12-01

    Highlights: • Powder particles of Ti, NiTi and Ti6Al4V are covered by homogeneous Ti-oxide layer. • Thickness of the Ti-oxide layer is in the range of 2.9 to 4.2 nm in as-atomized state. • Exposure to the air results in immediate oxide thickness increase of up to 30%. • Oxide thickness increase of only 15% during storage for 8 years. • High passivation of the Ti, NiTi and Ti6Al4V powder surface by Ti-oxide layer. - Abstract: High affinity of titanium to oxygen in combination with the high surface area of the powder results in tremendous powder reactivity and almost inevitable presence of passivation oxide film on the powder surface. Oxide film is formed during the short exposure of the powder to the environment at even a trace amount of oxygen. Hence, surface state of the powder determines its usefulness for powder metallurgy processing. Present study is focused on the evaluation of the surface oxide state of the Ti, NiTi and Ti6Al4V powders in as-atomized state and after storage under air or Ar for up to eight years. Powder surface oxide state was studied by X-ray photoelectron spectroscopy (XPS) and high resolution scanning electron microscopy (HR SEM). Results indicate that powder in as-atomized state is covered by homogeneous Ti-oxide layer with the thickness of ∼2.9 nm for Ti, ∼3.2 nm and ∼4.2 nm in case of Ti6Al4V and NiTi powders, respectively. Exposure to the air results in oxide growth of about 30% in case of Ti and only about 10% in case of NiTi and Ti6Al4V. After the storage under the dry air for two years oxide growth of only about 3-4% was detected in case of both, Ti and NiTi powders. NiTi powder, stored under the dry air for eight years, indicates oxide thickness of about 5.3 nm, which is about 30% thicker in comparison with the as-atomized powder. Oxide thickness increase of only ∼15% during the storage for eight years in comparison with the powder, shortly exposed to the air after manufacturing, was detected. Results indicate a

  6. Change of surface colour parameters during storage of paprika (Capsicum annuum L.

    Directory of Open Access Journals (Sweden)

    Belović Miona M.

    2014-01-01

    Full Text Available The change of paprika surface colour during three years of storage was monitored by measuring CIEL*a*b* colour parameters once a year. Ten commercial and three branded paprika samples, originating from Hungary, Austria and Serbia, were stored in original packaging at ambient temperature in dark during the storage period. The colour of paprika powder was measured by Chroma Meter CR-400 (Konica Minolta, Japan, using attachment for granular materials CR-A50. Directly measured colour parameters were CIE L* (lightness, a* (+a* = redness, -a* = greenness, b* (+b* = yellowness, -b* = blueness and dominant wavelength (DWL, while derived colour parameters were chroma (C*, hue angle (h°, and total colour change (ΔE. Paprika samples had similar granulation, and therefore it was concluded that it did not influence the colour reflection. The change of reflected colour of paprika powder during storage can be characterized by increase of CIE L* and b* colour values and decrease of a* colour value. Therefore, chroma values remained almost unchanged, while hue angle showed shift in spectrum from red-orange to orange-yellow, similarly to dominant wavelength. The paprika samples changed their colour most rapidly during the first year of storage, except the branded paprika from Serbia. Commercial paprika samples from Serbian market changed their colour more rapidly comparing to other investigated samples.

  7. Molecular dynamics simulation of annealed ZnO surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Min, Tjun Kit; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia)

    2015-04-24

    The effect of thermally annealing a slab of wurtzite ZnO, terminated by two surfaces, (0001) (which is oxygen-terminated) and (0001{sup ¯}) (which is Zn-terminated), is investigated via molecular dynamics simulation by using reactive force field (ReaxFF). We found that upon heating beyond a threshold temperature of ∼700 K, surface oxygen atoms begin to sublimate from the (0001) surface. The ratio of oxygen leaving the surface at a given temperature increases as the heating temperature increases. A range of phenomena occurring at the atomic level on the (0001) surface has also been explored, such as formation of oxygen dimers on the surface and evolution of partial charge distribution in the slab during the annealing process. It was found that the partial charge distribution as a function of the depth from the surface undergoes a qualitative change when the annealing temperature is above the threshold temperature.

  8. Structure and dynamics at the liquid surface of benzyl alcohol

    International Nuclear Information System (INIS)

    Dietter, J.; Morgner, H.

    1999-01-01

    A molecular dynamics simulation of a liquid layer of benzyl alcohol has been performed in order to compare the results with those obtained in experimental studies of our group. The main result of the experimental work was a strong orientational ordering of the benzyl alcohol molecules in the surface as well as an exceptionally large surface potential of ca. 0.6 V. According to the experiments the surface molecules orientate in such a way that the benzene ring points toward the vapor phase while the CH 2 group and the OH group are directed towards the bulk of the liquid. The simulation confirms this orientation of the surface molecules. The surface potential resulting from the simulation is 350 mV. The simulation reveals that the rather large surface potential can be understood as a consequence of the mean orientation of the molecular dipole moment in the surface region. The mean orientation of the molecules themselves in the surface is due to the tendency of the system to maintain the hydrogen bonding structure of the bulk in the surface region as well. The preferential orientation of the surface molecules causes a change of the dynamics of the individual components of the molecules when switching from bulk to surface which depends on the separation of these components from the polar group. This becomes most obvious in case of the reorientation dynamics of the molecular axes, e.g. the reorientation of the benzene ring is faster than the reorientation of the OH group. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  9. Effect of sealer coating and storage methods on the surface roughness of soft liners.

    Science.gov (United States)

    Usta Kutlu, Ilknur; Yanikoğlu, Nuran Dinckal; Kul, Esra; Duymuş, Zeynep Yesïl; Sağsöz, Nurdan Polat

    2016-03-01

    A soft lining is applied under a removable prosthesis for various reasons. The porosity of the lining material may increase colonization by microorganisms and cause tissue inflammation. The purpose of this in vitro study was to evaluate the effect of sealer coating on the surface roughness of soft lining materials under 4 different conditions. A total of 125 specimens were prepared. One high-temperature silicone-based soft lining material and 2 room-temperature-polymerized soft lining materials (1 silicone-based and 1 methacrylate-based) were used. Twenty-five specimens of each room-temperature soft lining material were coated with 2 layers of surface sealer. Additionally, 5 specimens of each material were stored in either distilled water, Coca-Cola, denture cleanser, saliva, or air. The surface roughness was measured at baseline and after 1, 7, 14, and 28 days. Surface roughness values were analyzed with repeated measures analysis of variance, and the Bonferroni multiple comparison test was performed using time-dependent groups and storage methods. In the time-dependent groups, methacrylate-based sealer-coated soft liners exhibited a significant increase in roughness (1.74-2.09 μm, P.05). Therefore, the sealer coating was not effective in reducing surface roughness. Among the time-dependent storage methods, the denture cleanser exhibited an almost significant increase in roughness (1.83-1.99 μm, P=.054). Coca-Cola and artificial saliva did not show a significant difference (P>.05). However, a significant decrease in roughness was found with distilled water (P=.02) and air (P<.001). Statistically significant differences in surface roughness were found among the different types of soft liners. The sealer coating had no significant effect, and denture cleanser slightly increased the surface roughness. Contrary to expectations, the roughness did not increase in all groups over time. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry

  10. Bayesian inversion analysis of nonlinear dynamics in surface heterogeneous reactions.

    Science.gov (United States)

    Omori, Toshiaki; Kuwatani, Tatsu; Okamoto, Atsushi; Hukushima, Koji

    2016-09-01

    It is essential to extract nonlinear dynamics from time-series data as an inverse problem in natural sciences. We propose a Bayesian statistical framework for extracting nonlinear dynamics of surface heterogeneous reactions from sparse and noisy observable data. Surface heterogeneous reactions are chemical reactions with conjugation of multiple phases, and they have the intrinsic nonlinearity of their dynamics caused by the effect of surface-area between different phases. We adapt a belief propagation method and an expectation-maximization (EM) algorithm to partial observation problem, in order to simultaneously estimate the time course of hidden variables and the kinetic parameters underlying dynamics. The proposed belief propagation method is performed by using sequential Monte Carlo algorithm in order to estimate nonlinear dynamical system. Using our proposed method, we show that the rate constants of dissolution and precipitation reactions, which are typical examples of surface heterogeneous reactions, as well as the temporal changes of solid reactants and products, were successfully estimated only from the observable temporal changes in the concentration of the dissolved intermediate product.

  11. Bulk-mediated surface diffusion: non-Markovian desorption dynamics

    International Nuclear Information System (INIS)

    Revelli, Jorge A; Budde, Carlos E; Prato, Domingo; Wio, Horacio S

    2005-01-01

    Here we analyse the dynamics of adsorbed molecules within the bulk-mediated surface diffusion framework, when the particle's desorption mechanism is characterized by a non-Markovian process, while the particle's adsorption as well as its motion in the bulk is governed by Markovian dynamics. We study the diffusion of particles in both semi-infinite and finite cubic lattices, analysing the conditional probability to find the system on the reference absorptive plane as well as the surface dispersion as functions of time. The results are compared with known Markovian cases showing the differences that can be exploited to distinguish between Markovian and non-Markovian desorption mechanisms in experimental situations

  12. Near-surface monitoring strategies for geologic carbon dioxide storage verification

    Energy Technology Data Exchange (ETDEWEB)

    Oldenburg, Curtis M.; Lewicki, Jennifer L.; Hepple, Robert P.

    2003-10-31

    Geologic carbon sequestration is the capture of anthropogenic carbon dioxide (CO{sub 2}) and its storage in deep geologic formations. Geologic CO{sub 2} storage verification will be needed to ensure that CO{sub 2} is not leaking from the intended storage formation and seeping out of the ground. Because the ultimate failure of geologic CO{sub 2} storage occurs when CO{sub 2} seeps out of the ground into the atmospheric surface layer, and because elevated concentrations of CO{sub 2} near the ground surface can cause health, safety, and environmental risks, monitoring will need to be carried out in the near-surface environment. The detection of a CO{sub 2} leakage or seepage signal (LOSS) in the near-surface environment is challenging because there are large natural variations in CO{sub 2} concentrations and fluxes arising from soil, plant, and subsurface processes. The term leakage refers to CO{sub 2} migration away from the intended storage site, while seepage is defined as CO{sub 2} passing from one medium to another, for example across the ground surface. The flow and transport of CO{sub 2} at high concentrations in the near-surface environment will be controlled by its high density, low viscosity, and high solubility in water relative to air. Numerical simulations of leakage and seepage show that CO{sub 2} concentrations can reach very high levels in the shallow subsurface even for relatively modest CO{sub 2} leakage fluxes. However, once CO{sub 2} seeps out of the ground into the atmospheric surface layer, surface winds are effective at dispersing CO{sub 2} seepage. In natural ecological systems with no CO{sub 2} LOSS, near-surface CO{sub 2} fluxes and concentrations are controlled by CO{sub 2} uptake by photosynthesis, and production by root respiration, organic carbon biodegradation in soil, deep outgassing of CO{sub 2}, and by exchange of CO{sub 2} with the atmosphere. Existing technologies available for monitoring CO{sub 2} in the near-surface environment

  13. Dynamic Heat Storage and Cooling Capacity of a Concrete Deck with PCM and Thermally Activated Building System

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    This paper presents a heat storage and cooling concept that utilizes a phase change material (PCM) and a thermally activated building system (TABS) implemented in a hollow core concrete deck. Numerical calculations of the dynamic heat storage capacity of the hollow core concrete deck element...... in the article highlight the potential of using TABS and PCM in a prefabricated concrete deck element....

  14. The electron beam dynamics simulation in the laser-electron storage ring involving compton and intrabeam scattering

    International Nuclear Information System (INIS)

    Gladkikh, P.I.; Telegin, Yu.N.; Karnaukhov, I.M.

    2002-01-01

    The feasibility of the development of intense X-ray sources based on Compton scattering in laser-electron storage rings is discussed. The results of the electron beam dynamics simulation involving Compton and intrabeam scattering are presented

  15. The electron beam dynamics simulation in the laser-electron storage ring involving compton and intrabeam scattering

    CERN Document Server

    Gladkikh, P I; Karnaukhov, I M

    2002-01-01

    The feasibility of the development of intense X-ray sources based on Compton scattering in laser-electron storage rings is discussed. The results of the electron beam dynamics simulation involving Compton and intrabeam scattering are presented.

  16. Nanoparticles dynamics on a surface: fractal pattern formation and fragmentation

    DEFF Research Database (Denmark)

    Dick, Veronika V.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2010-01-01

    In this paper we review our recent results on the formation and the post-growth relaxation processes of nanofractals on surface. For this study we developed a method which describes the internal dynamics of particles in a fractal and accounts for their diffusion and detachment. We demonstrate...... that these kinetic processes determine the final shape of the islands on surface after post-growth relaxation. We consider different scenarios of fractal relaxation and analyze the time evolution of the island's morphology....

  17. [Research on functional diversity of microorganisms on jujube fruit surface in storage].

    Science.gov (United States)

    Sha, Yuexia

    2009-10-01

    Disease during storage caused by microbial infection is a serious problem of jujube fruits. The aim of the study was to characterize the microbial diversity in stored jujube fruits. I used Biolog in experiment. The types of micro-plates were Filamentous Fungi micro-plate and Economicmicro-plate. There was much difference in microbial functional diversity on the surface of stored jujube fruit. The microbial functional diversity of stored 30 days was richer than it of stored 15 days. The diversity, homogeneity and average well color development of jujube used by fruit perservatives were lower than it not used by fruit preservatives. There were six kinds of the characteristic carbon. Our study firstly showed microbial diversity on the surface of stored jujube fruit. Biolog could be applied in the research on microbial functional diversity of fruit surface.

  18. A technique for the geometric modeling of underground surfaces: Nevada Nuclear Waste Storage Investigations Project

    International Nuclear Information System (INIS)

    Williams, R.L.

    1988-03-01

    There is a need within the Nevada Nuclear Waste Storage Investigation (NNWSI) project to develop three-dimensional surface definitions for the subterranean stratigraphies at Yucca Mountain, Nevada. The nature of the data samples available to the project require an interpolation technique that can perform well with sparse and irregularly spaced data. Following an evaluation of the relevant existing methods, a new technique, Multi-Kernel Modulation (MKM), is presented. MKM interpolates sparse and irregularly spaced data by modulating a polynomial trend surface with a linear summation of regular surfaces (kernels). A perspective discussion of MKM, Kriging, and Multiquadric Analysis reveals that MKM has the advantage of simplicity and efficiency when used with sparse samples. An example of the use of MKM to model a complex topography is presented. 24 refs., 6 figs., 2 tabs

  19. Structure, biomimetics, and fluid dynamics of fish skin surfaces*

    Science.gov (United States)

    Lauder, George V.; Wainwright, Dylan K.; Domel, August G.; Weaver, James C.; Wen, Li; Bertoldi, Katia

    2016-10-01

    The interface between the fluid environment and the surface of the body in swimming fishes is critical for both physiological and hydrodynamic functions. The skin surface in most species of fishes is covered with bony scales or toothlike denticles (in sharks). Despite the apparent importance of fish surfaces for understanding aquatic locomotion and near-surface boundary layer flows, relatively little attention has been paid to either the nature of surface textures in fishes or possible hydrodynamic effects of variation in roughness around the body surface within an individual and among species. Fish surfaces are remarkably diverse and in many bony fishes scales can have an intricate surface texture with projections, ridges, and comblike extensions. Shark denticles (or scales) are toothlike and project out of the skin to form a complexly textured surface that interacts with free-stream flow. Manufacturing biomimetic foils with fishlike surfaces allows hydrodynamic testing and we emphasize here the importance of dynamic test conditions where the effect of surface textures is assessed under conditions of self-propulsion. We show that simple two-dimensional foils with patterned cuts do not perform as well as a smooth control surface, but that biomimetic shark skin foils can swim at higher self-propelled speeds than smooth controls. When the arrangement of denticles on the foil surface is altered, we find that a staggered-overlapped pattern outperforms other arrangements. Flexible foils made of real shark skin outperform sanded controls when foils are moved with a biologically realistic motion program. We suggest that focus on the mechanisms of drag reduction by fish surfaces has been too limiting and an additional role of fish surface textures may be to alter leading edge vortices and flow patterns on moving surfaces in a way that enhances thrust. Analysis of water flow over an artificial shark skin foil under both static and dynamic conditions shows that a shear layer

  20. Electrostatic cloaking of surface structure for dynamic wetting

    Science.gov (United States)

    Shiomi, Junichiro; Nita, Satoshi; Do-Quang, Minh; Wang, Jiayu; Chen, Yu-Chung; Suzuki, Yuji; Amberg, Gustav

    2017-11-01

    Dynamic wetting problems are fundamental to the understanding of the interaction between liquids and solids. Even in a superficially simple experimental situation, such as a droplet spreading over a dry surface, the result may depend not only on the liquid properties but also strongly on the substrate-surface properties; even for macroscopically smooth surfaces, the microscopic geometrical roughness can be important. In addition, as surfaces may often be naturally charged, or electric fields are used to manipulate fluids, electric effects are crucial components that influence wetting phenomena. Here we investigate the interplay between electric forces and surface structures in dynamic wetting. While surface microstructures can significantly hinder the spreading, we find that the electrostatics can ``cloak'' the microstructures, i.e. deactivate the hindering. We identify the physics in terms of reduction in contact-line friction, which makes the dynamic wetting inertial force dominant and insensitive to the substrate properties. This work was financially supported in part by, the Japan Society for the Promotion of Science, Swedish Governmental Agency for Innovation Systems, and the Japan Science and Technology Agency.

  1. Sub-nanometer glass surface dynamics induced by illumination

    International Nuclear Information System (INIS)

    Nguyen, Duc; Nienhaus, Lea; Haasch, Richard T.; Lyding, Joseph; Gruebele, Martin

    2015-01-01

    Illumination is known to induce stress and morphology changes in opaque glasses. Amorphous silicon carbide (a-SiC) has a smaller bandgap than the crystal. Thus, we were able to excite with 532 nm light a 1 μm amorphous surface layer on a SiC crystal while recording time-lapse movies of glass surface dynamics by scanning tunneling microscopy (STM). Photoexcitation of the a-SiC surface layer through the transparent crystal avoids heating the STM tip. Up to 6 × 10 4 s, long movies of surface dynamics with 40 s time resolution and sub-nanometer spatial resolution were obtained. Clusters of ca. 3-5 glass forming units diameter are seen to cooperatively hop between two states at the surface. Photoexcitation with green laser light recruits immobile clusters to hop, rather than increasing the rate at which already mobile clusters hop. No significant laser heating was observed. Thus, we favor an athermal mechanism whereby electronic excitation of a-SiC directly controls glassy surface dynamics. This mechanism is supported by an exciton migration-relaxation-thermal diffusion model. Individual clusters take ∼1 h to populate states differently after the light intensity has changed. We believe the surrounding matrix rearranges slowly when it is stressed by a change in laser intensity, and clusters serve as a diagnostic. Such cluster hopping and matrix rearrangement could underlie the microscopic mechanism of photoinduced aging of opaque glasses

  2. The effect of oxygen storage capacity on the dynamic characteristics of an automotive catalytic converter

    International Nuclear Information System (INIS)

    Shamim, Tariq

    2008-01-01

    Automotive catalytic converters, which are employed to reduce engine exhaust emissions, are subjected to highly transient conditions during a typical driving cycle. These transient conditions arise from changes in driving mode, the hysteresis and flow lags of the feedback control system, and result in fluctuations of air-fuel ratio, exhaust gas flow rates and temperatures. The catalyst performance is also strongly influenced by the oxygen storage capacity. This paper presents a computational investigation of the effect of oxygen storage capacity on the dynamic behavior of an automotive catalytic converter subjected to modulations in exhaust gases. The modulations are generated by forcing the temporal variations in exhaust gases air-fuel ratio, gas flow rates and temperatures. The study employs a single-channel based, one-dimensional, non-adiabatic model. The results show that the imposed modulations cause a significant departure in the catalyst behavior from its steady behavior, and the oxygen storage capacity plays an important role in determining the catalyst's response to the imposed modulations. Modulations and oxygen storage capacity are found to have relatively greater influence on the catalyst's performance near stoichiometric conditions

  3. The effect of oxygen storage capacity on the dynamic characteristics of an automotive catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Shamim, Tariq [Department of Mechanical Engineering, The University of Michigan-Dearborn, Dearborn, MI 48128-2406 (United States)

    2008-11-15

    Automotive catalytic converters, which are employed to reduce engine exhaust emissions, are subjected to highly transient conditions during a typical driving cycle. These transient conditions arise from changes in driving mode, the hysteresis and flow lags of the feedback control system, and result in fluctuations of air-fuel ratio, exhaust gas flow rates and temperatures. The catalyst performance is also strongly influenced by the oxygen storage capacity. This paper presents a computational investigation of the effect of oxygen storage capacity on the dynamic behavior of an automotive catalytic converter subjected to modulations in exhaust gases. The modulations are generated by forcing the temporal variations in exhaust gases air-fuel ratio, gas flow rates and temperatures. The study employs a single-channel based, one-dimensional, non-adiabatic model. The results show that the imposed modulations cause a significant departure in the catalyst behavior from its steady behavior, and the oxygen storage capacity plays an important role in determining the catalyst's response to the imposed modulations. Modulations and oxygen storage capacity are found to have relatively greater influence on the catalyst's performance near stoichiometric conditions. (author)

  4. Dynamic Bubble Surface Tension Measurements in Northwest Atlantic Seawater

    Science.gov (United States)

    Kieber, D. J.; Long, M. S.; Keene, W. C.; Kinsey, J. D.; Frossard, A. A.; Beaupre, S. R.; Duplessis, P.; Maben, J. R.; Lu, X.; Chang, R.; Zhu, Y.; Bisgrove, J.

    2017-12-01

    Numerous reports suggest that most organic matter (OM) associated with newly formed primary marine aerosol (PMA) originates from the sea-surface microlayer. However, surface-active OM rapidly adsorbs onto bubble surfaces in the water column and is ejected into the atmosphere when bubbles burst at the air-water interface. Here we present dynamic surface tension measurements of bubbles produced in near surface seawater from biologically productive and oligotrophic sites and in deep seawater collected from 2500 m in the northwest Atlantic. In all cases, the surface tension of bubble surfaces decreased within seconds after the bubbles were exposed to seawater. These observations demonstrate that bubble surfaces are rapidly saturated by surfactant material scavenged from seawater. Spatial and diel variability in bubble surface evolution indicate corresponding variability in surfactant concentrations and/or composition. Our results reveal that surface-active OM is found throughout the water column, and that at least some surfactants are not of recent biological origin. Our results also support the hypothesis that the surface microlayer is a minor to negligible source of OM associated with freshly produced PMA.

  5. Dynamic Exergy Analysis for the Thermal Storage Optimization of the Building Envelope

    Directory of Open Access Journals (Sweden)

    Valentina Bonetti

    2017-01-01

    Full Text Available As a measure of energy “quality”, exergy is meaningful for comparing the potential for thermal storage. Systems containing the same amount of energy could have considerably different capabilities in matching a demand profile, and exergy measures this difference. Exergy stored in the envelope of buildings is central in sustainability because the environment could be an unlimited source of energy if its interaction with the envelope is optimised for maintaining the indoor conditions within comfort ranges. Since the occurring phenomena are highly fluctuating, a dynamic exergy analysis is required; however, dynamic exergy modelling is complex and has not hitherto been implemented in building simulation tools. Simplified energy and exergy assessments are presented for a case study in which thermal storage determines the performance of seven different wall types for utilising nocturnal ventilation as a passive cooling strategy. Hourly temperatures within the walls are obtained with the ESP-r software in free-floating operation and are used to assess the envelope exergy storage capacity. The results for the most suitable wall types were different between the exergy analysis and the more traditional energy performance indicators. The exergy method is an effective technique for selecting the construction type that results in the most favourable free-floating conditions through the analysed passive strategy.

  6. Thermodynamic model of a thermal storage air conditioning system with dynamic behavior

    International Nuclear Information System (INIS)

    Fleming, Evan; Wen, Shaoyi; Shi, Li; Silva, Alexandre K. da

    2013-01-01

    Highlights: • We developed an automotive thermal storage air conditioning system model. • The thermal storage unit utilizes phase change materials. • We use semi-analytic solution to the coupled phase change and forced convection. • We model the airside heat exchange using the NTU method. • The system model can incorporate dynamic inputs, e.g. variable inlet airflow. - Abstract: A thermodynamic model was developed to predict transient behavior of a thermal storage system, using phase change materials (PCMs), for a novel electric vehicle climate conditioning application. The main objectives of the paper are to consider the system’s dynamic behavior, such as a dynamic air flow rate into the vehicle’s cabin, and to characterize the transient heat transfer process between the thermal storage unit and the vehicle’s cabin, while still maintaining accurate solution to the complex phase change heat transfer. The system studied consists of a heat transfer fluid circulating between either of the on-board hot and cold thermal storage units, which we refer to as thermal batteries, and a liquid–air heat exchanger that provides heat exchange with the incoming air to the vehicle cabin. Each thermal battery is a shell-and-tube configuration where a heat transfer fluid flows through parallel tubes, which are surrounded by PCM within a larger shell. The system model incorporates computationally inexpensive semi-analytic solution to the conjugated laminar forced convection and phase change problem within the battery and accounts for airside heat exchange using the Number of Transfer Units (NTUs) method for the liquid–air heat exchanger. Using this approach, we are able to obtain an accurate solution to the complex heat transfer problem within the battery while also incorporating the impact of the airside heat transfer on the overall system performance. The implemented model was benchmarked against a numerical study for a melting process and against full system

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

    Directory of Open Access Journals (Sweden)

    Yang Yu

    2013-01-01

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

  8. Tracking studies of insertion device effects on dynamic aperture in the APS storage ring

    International Nuclear Information System (INIS)

    Chae, Yong-chul; Crosbie, E.A.

    1993-01-01

    We studied the effects of an insertion device (ID) on the dynamic aperture in the 7-GeV Advanced Photon Source (APS) storage ring using the program RACETRACK. We found that the nonlinear effect of the ID is the dominant effect on the dynamic aperture reduction compared to the other multipole errors which exist in the otherwise ideal lattice. The previous study of dynamic aperture was based on the assumption that the effect of the fast oscillating terms in L. Smith's Hamiltonian is small, and hence can be neglected in the simulation. The remarkable agreement between the previous study and the current results using RACETRACK, including all effects of the fast oscillating terms, justified those assumptions at least for the APS ring

  9. Effect of water table dynamics on land surface hydrologic memory

    Science.gov (United States)

    Lo, Min-Hui; Famiglietti, James S.

    2010-11-01

    The representation of groundwater dynamics in land surface models has received considerable attention in recent years. Most studies have found that soil moisture increases after adding a groundwater component because of the additional supply of water to the root zone. However, the effect of groundwater on land surface hydrologic memory (persistence) has not been explored thoroughly. In this study we investigate the effect of water table dynamics on National Center for Atmospheric Research Community Land Model hydrologic simulations in terms of land surface hydrologic memory. Unlike soil water or evapotranspiration, results show that land surface hydrologic memory does not always increase after adding a groundwater component. In regions where the water table level is intermediate, land surface hydrologic memory can even decrease, which occurs when soil moisture and capillary rise from groundwater are not in phase with each other. Further, we explore the hypothesis that in addition to atmospheric forcing, groundwater variations may also play an important role in affecting land surface hydrologic memory. Analyses show that feedbacks of groundwater on land surface hydrologic memory can be positive, negative, or neutral, depending on water table dynamics. In regions where the water table is shallow, the damping process of soil moisture variations by groundwater is not significant, and soil moisture variations are mostly controlled by random noise from atmospheric forcing. In contrast, in regions where the water table is very deep, capillary fluxes from groundwater are small, having limited potential to affect soil moisture variations. Therefore, a positive feedback of groundwater to land surface hydrologic memory is observed in a transition zone between deep and shallow water tables, where capillary fluxes act as a buffer by reducing high-frequency soil moisture variations resulting in longer land surface hydrologic memory.

  10. Implications of long-term surface or near-surface storage of intermediate and low-level wastes in the UK

    International Nuclear Information System (INIS)

    Murray, N.; Vande Putte, D.; Ware, R.J.

    1986-02-01

    Various options for 200 year-long storage of all Low- and Intermediate-Level wastes generated to the year 2030 are considered. On-site storage and centralised storage have been examined and compared. The feasibility of storing some of the wastes in underground facilities that are convertible to repositories has been demonstrated, but it is shown that centralised, surface storage of wastes would be more economical. There appears to be little merit in storing Intermediate Level wastes in separate facilities that could be converted to repositories. Storage is shown to be more expensive than direct disposal, except if future costs are discounted by more than about 10%. With carefully designed stores and remote handling, the collective dose to operators could be limited to about 20-40 man Sv over the whole period of storage. (author)

  11. DNSC08 mean sea surface and mean dynamic topography models

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Knudsen, Per

    2009-01-01

    -2004. It is the first global MSS without a polar gap including all of the Arctic Ocean by including laser altimetry from the ICESat mission. The mean dynamic topography (MDT) is the quantity that bridges the geoid and the mean sea surface constraining large-scale ocean circulation. Here we present a new high...

  12. Surface Dynamic Process Simulation with the Use of Cellular Automata

    International Nuclear Information System (INIS)

    Adamska-Szatko, M.; Bala, J.

    2010-01-01

    Cellular automata are known for many applications, especially for physical and biological simulations. Universal cellular automata can be used for modelling complex natural phenomena. The paper presents simulation of surface dynamic process. Simulation uses 2-dimensional cellular automata algorithm. Modelling and visualisation were created by in-house developed software with standard OpenGL graphic library. (authors)

  13. Ti and Zr surfaces studied by molecular dynamics

    International Nuclear Information System (INIS)

    Pascuet, Maria I.; Passianot, Roberto C.; Monti, Ana M.

    2003-01-01

    The interaction between point defects technique and the (0001), (1-210), (10-10) surfaces in Ti and Zr is studied by the molecular dynamics technique. Both of metals are in the hexagonal structure and within a temperature range of 100 to 900 K. The atomic interactions are modeled by EAM-type many-body potentials, that were used previously in static simulations. New migration mechanisms are unraveled and others are verified with respect to those already proposed in the static studies. Also included is an analysis of the vacancy stability in the sub-surface layers of the prismatic surfaces. (author)

  14. Dynamics of a Flywheel Energy Storage System Supporting a Wind Turbine Generator in a Microgrid

    Science.gov (United States)

    Nair S, Gayathri; Senroy, Nilanjan

    2016-02-01

    Integration of an induction machine based flywheel energy storage system with a wind energy conversion system is implemented in this paper. The nonlinear and linearized models of the flywheel are studied, compared and a reduced order model of the same simulated to analyze the influence of the flywheel inertia and control in system response during a wind power change. A quantification of the relation between the inertia of the flywheel and the controller gain is obtained which allows the system to be considered as a reduced order model that is more controllable in nature. A microgrid setup comprising of the flywheel energy storage system, a two mass model of a DFIG based wind turbine generator and a reduced order model of a diesel generator is utilized to analyse the microgrid dynamics accurately in the event of frequency variations arising due to wind power change. The response of the microgrid with and without the flywheel is studied.

  15. Applications of differential algebra to single-particle dynamics in storage rings

    International Nuclear Information System (INIS)

    Yan, Y.

    1991-09-01

    Recent developments in the use of differential algebra to study single-particle beam dynamics in charged-particle storage rings are the subject of this paper. Chapter 2 gives a brief review of storage rings. The concepts of betatron motion and synchrotron motion, and their associated resonances, are introduced. Also introduced are the concepts of imperfections, such as off-momentum, misalignment, and random and systematic errors, and their associated corrections. The chapter concludes with a discussion of numerical simulation principles and the concept of one-turn periodic maps. In Chapter 3, the discussion becomes more focused with the introduction of differential algebras. The most critical test for differential algebraic mapping techniques -- their application to long-term stability studies -- is discussed in Chapter 4. Chapter 5 presents a discussion of differential algebraic treatment of dispersed betatron motion. The paper concludes in Chapter 6 with a discussion of parameterization of high-order maps

  16. UCN storage experiment for the investigation of the anomalous interaction with wall surfaces

    International Nuclear Information System (INIS)

    Kawabata, Yuji; Utsuro, Masahiko; Steyerl, A.; Malik, S.S.; Geltenbort, P.; Neumair, S.; Nesvizhevsky, V.V.

    1997-01-01

    The UCN experiment for the investigation of the anomalous interaction with wall surfaces was performed in the ILL UCN source. UCN is monochromated by the gravity and stored in the spectrometer with rectangular trap which is the Fombrin-grease coated box of 67x67cm 2 cross section and 20cm height. The measured energy distribution of stored UCN shows the indication of 'initial micro-heating'. The order of energy gain is ∼ 10 -10 eV in the initial several 100sec of storage. (author)

  17. Application of autonomous robotics to surveillance of waste storage containers for radioactive surface contamination

    International Nuclear Information System (INIS)

    Sweeney, F.J.; Beckerman, M.; Butler, P.L.; Jones, J.P.; Reister, D.B.

    1991-01-01

    This paper describes a proof-of-principal demonstration performed with the HERMIES-III mobile robot to automate the inspection of waste storage drums for radioactive surface contamination and thereby reduce the human burden of operating a robot and worker exposure to potentially hazardous environments. Software and hardware for the demonstration were developed by a team consisting of Oak Ridge National Laboratory, and the Universities of Florida, Michigan, Tennessee, and Texas. Robot navigation, machine vision, manipulator control, parallel processing and human-machine interface techniques developed by the team were demonstrated utilizing advanced computer architectures. The demonstration consists of over 100,000 lines of computer code executing on nine computers

  18. Decay of surface nanostructures via long-time-scale dynamics

    International Nuclear Information System (INIS)

    Voter, A.F.; Stanciu, N.

    1998-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors have developed a new approach for extending the time scale of molecular dynamics simulations. For infrequent-event systems, the category that includes most diffusive events in the solid phase, this hyperdynamics method can extend the simulation time by a few orders of magnitude compared to direct molecular dynamics. The trajectory is run on a potential surface that has been biased to raise the energy in the potential basins without affecting the transition state region. The method is described and applied to surface and bulk diffusion processes, achieving microsecond and millisecond simulation times. The authors have also developed a new parallel computing method that is efficient for small system sizes. The combination of the hyperdynamics with this parallel replica dynamics looks promising as a general materials simulation tool

  19. Reaction dynamics of molecular hydrogen on silicon surfaces

    DEFF Research Database (Denmark)

    Bratu, P.; Brenig, W.; Gross, A.

    1996-01-01

    of the preexponential factor by about one order of magnitude per lateral degree of freedom. Molecular vibrations have practically no effect on the adsorption/desorption dynamics itself, but lead to vibrational heating in desorption with a strong isotope effect. Ab initio calculations for the H-2 interaction...... between the two surfaces. These results indicate that tunneling, molecular vibrations, and the structural details of the surface play only a minor role for the adsorption dynamics. Instead, they appear to be governed by the localized H-Si bonding and Si-Si lattice vibrations. Theoretically, an effective......Experimental and theoretical results on the dynamics of dissociative adsorption and recombinative desorption of hydrogen on silicon are presented. Using optical second-harmonic generation, extremely small sticking probabilities in the range 10(-9)-10(-5) could be measured for H-2 and D-2 on Si(111...

  20. REDOX POTENTIAL AND DYNAMICS OF PROTEIN AND FAT DESTRUCTION DURING STORAGE OF CANNED MEAT IN PIECES

    Directory of Open Access Journals (Sweden)

    V. B. Krylova

    2016-01-01

    Full Text Available The studies on the dynamics of the redox potential of systems and its relationship with the processes of protein and fat destruction in canned foods during their storage are fragmented and not systemized, which highlight their topicality. The aim of the research was to obtain the experimental data on the Eh values and physico-chemical indicators of canned food quality during storage in order to establish their possible correlation. It was shown that the dynamics of Eh, the content of free amino acids and fatty acid fractions in the canned products from beef and pork was different during storage. For example, a decrease in the Eh value and free amino acid content in the canned products from beef had a smooth character, while in the canned products from pork several periods were observed, which differed in the character of the change in the quality indicators.A linear character of the changes in the proportion of fatty acid fractions during storage of the canned products from beef and pork was noticed. With that, both canned food items had an increase in the saturated fatty acid content at the concomitant decrease in the sum of mono- and polyunsaturated fatty acids. The value of an increase in the proportion of saturated fatty acids associated with the process of reduction of mono- and polyunsaturated fatty acids did not depend on the kind of meat in the canned foods and was on average 6%. A decrease in the proportion of mono- and polyunsaturated fatty acids in the canned products from pork was about 4 times more intensive compared to the canned products from beef.

  1. Critical bifurcation surfaces of 3D discrete dynamics

    Directory of Open Access Journals (Sweden)

    Michael Sonis

    2000-01-01

    Full Text Available This paper deals with the analytical representation of bifurcations of each 3D discrete dynamics depending on the set of bifurcation parameters. The procedure of bifurcation analysis proposed in this paper represents the 3D elaboration and specification of the general algorithm of the n-dimensional linear bifurcation analysis proposed by the author earlier. It is proven that 3D domain of asymptotic stability (attraction of the fixed point for a given 3D discrete dynamics is bounded by three critical bifurcation surfaces: the divergence, flip and flutter surfaces. The analytical construction of these surfaces is achieved with the help of classical Routh–Hurvitz conditions of asymptotic stability. As an application the adjustment process proposed by T. Puu for the Cournot oligopoly model is considered in detail.

  2. Thermodynamic model of a thermal storage air conditioning system with dynamic behavior

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, E; Wen, SY; Shi, L; da Silva, AK

    2013-12-01

    A thermodynamic model was developed to predict transient behavior of a thermal storage system, using phase change materials (PCMs), for a novel electric vehicle climate conditioning application. The main objectives of the paper are to consider the system's dynamic behavior, such as a dynamic air flow rate into the vehicle's cabin, and to characterize the transient heat transfer process between the thermal storage unit and the vehicle's cabin, while still maintaining accurate solution to the complex phase change heat transfer. The system studied consists of a heat transfer fluid circulating between either of the on-board hot and cold thermal storage units, which we refer to as thermal batteries, and a liquid-air heat exchanger that provides heat exchange with the incoming air to the vehicle cabin. Each thermal battery is a shell-and-tube configuration where a heat transfer fluid flows through parallel tubes, which are surrounded by PCM within a larger shell. The system model incorporates computationally inexpensive semianalytic solution to the conjugated laminar forced convection and phase change problem within the battery and accounts for airside heat exchange using the Number of Transfer Units (NTUs) method for the liquid-air heat exchanger. Using this approach, we are able to obtain an accurate solution to the complex heat transfer problem within the battery while also incorporating the impact of the airside heat transfer on the overall system performance. The implemented model was benchmarked against a numerical study for a melting process and against full system experimental data for solidification using paraffin wax as the PCM. Through modeling, we demonstrate the importance of capturing the airside heat exchange impact on system performance, and we investigate system response to dynamic operating conditions, e.g., air recirculation. (C) 2013 Elsevier Ltd. All rights reserved.

  3. Dynamic Modeling of Adjustable-Speed Pumped Storage Hydropower Plant: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E.; Singh, M.; Gevorgian, V.; Mohanpurkar, M.; Havsapian, R.; Koritarov, V.

    2015-04-06

    Hydropower is the largest producer of renewable energy in the U.S. More than 60% of the total renewable generation comes from hydropower. There is also approximately 22 GW of pumped storage hydropower (PSH). Conventional PSH uses a synchronous generator, and thus the rotational speed is constant at synchronous speed. This work details a hydrodynamic model and generator/power converter dynamic model. The optimization of the hydrodynamic model is executed by the hydro-turbine controller, and the electrical output real/reactive power is controlled by the power converter. All essential controllers to perform grid-interface functions and provide ancillary services are included in the model.

  4. Dynamic Modelling of a Solar Water Pumping System with Energy Storage

    OpenAIRE

    Shatadru Biswas; M. Tariq Iqbal

    2018-01-01

    This paper describes the dynamic modelling of a system used for extraction of groundwater for irrigation using an alternative source of energy. The system is designed based on data of an existing project in Lalmonirhat, Bangladesh. The system comprises a 38.4 kWp solar photovoltaic array, inverter, AC motor, and pump set, which can discharge a maximum of 1,930 m3 of water per day. MATLAB simulation is performed with two types of energy storage system: (i) electric energy using a battery bank ...

  5. Thermal energy storage for organic Rankine cycle solar dynamic space power systems

    Science.gov (United States)

    Heidenreich, G. R.; Parekh, M. B.

    An organic Rankine cycle-solar dynamic power system (ORC-SDPS) comprises a concentrator, a radiator, a power conversion unit, and a receiver with a thermal energy storage (TES) subsystem which charges and discharges energy to meet power demands during orbital insolation and eclipse periods. Attention is presently given to the criteria used in designing and evaluating an ORC-SDPS TES, as well as the automated test facility employed. It is found that a substantial data base exists for the design of an ORC-SDPS TES subsystem.

  6. Investigating the dynamics of surface-immobilized DNA nanomachines

    Science.gov (United States)

    Dunn, Katherine E.; Trefzer, Martin A.; Johnson, Steven; Tyrrell, Andy M.

    2016-07-01

    Surface-immobilization of molecules can have a profound influence on their structure, function and dynamics. Toehold-mediated strand displacement is often used in solution to drive synthetic nanomachines made from DNA, but the effects of surface-immobilization on the mechanism and kinetics of this reaction have not yet been fully elucidated. Here we show that the kinetics of strand displacement in surface-immobilized nanomachines are significantly different to those of the solution phase reaction, and we attribute this to the effects of intermolecular interactions within the DNA layer. We demonstrate that the dynamics of strand displacement can be manipulated by changing strand length, concentration and G/C content. By inserting mismatched bases it is also possible to tune the rates of the constituent displacement processes (toehold-binding and branch migration) independently, and information can be encoded in the time-dependence of the overall reaction. Our findings will facilitate the rational design of surface-immobilized dynamic DNA nanomachines, including computing devices and track-based motors.

  7. Dynamics of ice nucleation on water repellent surfaces.

    Science.gov (United States)

    Alizadeh, Azar; Yamada, Masako; Li, Ri; Shang, Wen; Otta, Shourya; Zhong, Sheng; Ge, Liehui; Dhinojwala, Ali; Conway, Ken R; Bahadur, Vaibhav; Vinciquerra, A Joseph; Stephens, Brian; Blohm, Margaret L

    2012-02-14

    Prevention of ice accretion and adhesion on surfaces is relevant to many applications, leading to improved operation safety, increased energy efficiency, and cost reduction. Development of passive nonicing coatings is highly desirable, since current antiicing strategies are energy and cost intensive. Superhydrophobicity has been proposed as a lead passive nonicing strategy, yet the exact mechanism of delayed icing on these surfaces is not clearly understood. In this work, we present an in-depth analysis of ice formation dynamics upon water droplet impact on surfaces with different wettabilities. We experimentally demonstrate that ice nucleation under low-humidity conditions can be delayed through control of surface chemistry and texture. Combining infrared (IR) thermometry and high-speed photography, we observe that the reduction of water-surface contact area on superhydrophobic surfaces plays a dual role in delaying nucleation: first by reducing heat transfer and second by reducing the probability of heterogeneous nucleation at the water-substrate interface. This work also includes an analysis (based on classical nucleation theory) to estimate various homogeneous and heterogeneous nucleation rates in icing situations. The key finding is that ice nucleation delay on superhydrophobic surfaces is more prominent at moderate degrees of supercooling, while closer to the homogeneous nucleation temperature, bulk and air-water interface nucleation effects become equally important. The study presented here offers a comprehensive perspective on the efficacy of textured surfaces for nonicing applications.

  8. Evaluation of Dynamic Behavior of Pile Foundations for Interim Storage Facilities Through Geotechnical Centrifuge Tests

    International Nuclear Information System (INIS)

    Shizuo Tsurumaki; Hiroyuki Watanabe; Akira Tateishi; Kenichi Horikoshi; Shunichi Suzuki

    2002-01-01

    In Japan, there is a possibility that interim storage facilities for recycled nuclear fuel resources may be constructed on quaternary layers, rather than on hard rock. In such a case, the storage facilities need to be supported by pile foundations or spread foundations to meet the required safety level. The authors have conducted a series of experimental studies on the dynamic behavior of storage facilities supported by pile foundations. A centrifuge modeling technique was used to satisfy the required similitude between the reduced size model and the prototype. The centrifuge allows a high confining stress level equivalent to prototype deep soils to be generated (which is considered necessary for examining complex pile-soil interactions) as the soil strength and the deformation are highly dependent on the confining stress. The soil conditions were set at as experimental variables, and the results are compared. Since 2000, the Nuclear Power Engineering Corporation (NUPEC) has been conducting these research tests under the auspices on the Ministry of Economy, Trade and Industry of Japan. (authors)

  9. Selection of high temperature thermal energy storage materials for advanced solar dynamic space power systems

    Science.gov (United States)

    Lacy, Dovie E.; Coles-Hamilton, Carolyn; Juhasz, Albert

    1987-01-01

    Under the direction of NASA's Office of Aeronautics and Technology (OAST), the NASA Lewis Research Center has initiated an in-house thermal energy storage program to identify combinations of phase change thermal energy storage media for use with a Brayton and Stirling Advanced Solar Dynamic (ASD) space power system operating between 1070 and 1400 K. A study has been initiated to determine suitable combinations of thermal energy storage (TES) phase change materials (PCM) that result in the smallest and lightest weight ASD power system possible. To date the heats of fusion of several fluoride salt mixtures with melting points greater than 1025 K have been verified experimentally. The study has indicated that these salt systems produce large ASD systems because of their inherent low thermal conductivity and low density. It is desirable to have PCMs with high densities and high thermal conductivities. Therefore, alternate phase change materials based on metallic alloy systems are also being considered as possible TES candidates for future ASD space power systems.

  10. Simulation of spin dynamics to measure electric dipole moments in storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, Marcel; Lehrach, Andreas [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik; Collaboration: JEDI-Collaboration

    2013-07-01

    CP violation in the baryon sector, which is predicted by the Standard Model of Particle Physics, is too small to explain the matter and antimatter asymmetry in our universe. Permanent Electric Dipole Moments (EDMs) violate both P and T symmetries and are therefore, through the CPT theorem, also CP violating. No direct EDM measurements for protons, deuterons and light nuclei have been performed up to now. The JEDI collaboration at Forschungszentrum Juelich (FZJ) and the BNL-EDM collaboration at Brookhaven National Laboratory (BNL) pursue the goal to measure the EDMs of these particles in dedicated storage rings. Therefore different approaches are studied to reach an ultimate sensitivity of 10{sup -29} e.cm. A first direct measurement of the proton and deuteron EDM at a sensitivity level of 10{sup -24} e.cm will be performed in the existing conventional storage ring at FZJ, the Cooler Synchrotron COSY. Particle tracking simulations to explore the motion-correlated spin dynamics are a crucial part of feasibility studies of the planned storage ring EDM experiments. In a first step, a benchmarking of simulation codes with measurements at the Cooler Synchrotron COSY is performed.

  11. Influence of chemistry on wetting dynamics of nanotextured hydrophobic surfaces.

    Science.gov (United States)

    Di Mundo, Rosa; Palumbo, Fabio; d'Agostino, Riccardo

    2010-04-06

    In this work, the role of a chemical parameter, such as the degree of fluorination, on the wetting behavior of nanotextured hydrophobic surfaces is investigated. Texture and chemistry tuning of the surfaces has been accomplished with single batch radiofrequency low-pressure plasma processes. Polystyrene substrates have been textured by CF(4) plasma etching and subsequently covered by thin films with a tunable F-to-C ratio, obtained in discharges fed with C(4)F(8)-C(2)H(4). Measurements of wetting dynamics reveal a regime transition from adhesive-hydrophobic to slippery-superhydrophobic, i.e., from wet to non wet states, as the F-to-C rises at constant topography. Such achievements are strengthened by calculation of the solid fraction of surface water contact area applying Cassie-Baxter advancing and receding equations to water contact angle data of textured and flat reference surfaces.

  12. He atom-surface scattering: Surface dynamics of insulators, overlayers and crystal growth

    International Nuclear Information System (INIS)

    Safron, S.A.; Skofronick, J.G.

    1994-01-01

    This progress report describes work carried out in the study of surface structure and dynamics of ionic insulators, the microscopic interactions controlling epitaxial growth and the formation of overlayers, and energy exchange in multiphonon surface scattering. The approach used is to employ high resolution helium atom scattering to study the geometry and structural features of the surfaces. Experiments have been carried out on the surface dynamics of RbCl and preliminary studies done on CoO and NiO. Epitaxial growth and overlayer dynamics experiments on the systems NaCl/NaCl(001), KBr/NaCl(001), NaCl/KBr(001) and KBr/RbCl(001) have been performed. They have collaborated with two theoretical groups to explore models of overlayer dynamics with which to compare and to interpret their experimental results. They have carried out extensive experiments on the multiphonon scattering of helium atoms from NaCl and, particularly, LiF. Work has begun on self-assembling organic films on gold and silver surfaces (alkyl thiols/Au(111) and Ag(111))

  13. Engineering the surface of rutile TiO2 nanoparticles with quantum pits towards excellent lithium storage

    DEFF Research Database (Denmark)

    Huang, Jinglu; Fang, Fang; Huang, Guoyong

    2016-01-01

    Engineering the surface structure of nanomaterials is of great importance for applications in energy conversion and storage. Herein, unique rutile TiO2 nanoparticles have been successfully synthesized by a facile solution and subsequent thermal annealing method. Each particle surface has been...

  14. Modeling Apple Surface Temperature Dynamics Based on Weather Data

    Directory of Open Access Journals (Sweden)

    Lei Li

    2014-10-01

    Full Text Available The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed was recorded for seven hours between 11:00–18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of “Fuji” apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management.

  15. Modeling apple surface temperature dynamics based on weather data.

    Science.gov (United States)

    Li, Lei; Peters, Troy; Zhang, Qin; Zhang, Jingjin; Huang, Danfeng

    2014-10-27

    The exposure of fruit surfaces to direct sunlight during the summer months can result in sunburn damage. Losses due to sunburn damage are a major economic problem when marketing fresh apples. The objective of this study was to develop and validate a model for simulating fruit surface temperature (FST) dynamics based on energy balance and measured weather data. A series of weather data (air temperature, humidity, solar radiation, and wind speed) was recorded for seven hours between 11:00-18:00 for two months at fifteen minute intervals. To validate the model, the FSTs of "Fuji" apples were monitored using an infrared camera in a natural orchard environment. The FST dynamics were measured using a series of thermal images. For the apples that were completely exposed to the sun, the RMSE of the model for estimating FST was less than 2.0 °C. A sensitivity analysis of the emissivity of the apple surface and the conductance of the fruit surface to water vapour showed that accurate estimations of the apple surface emissivity were important for the model. The validation results showed that the model was capable of accurately describing the thermal performances of apples under different solar radiation intensities. Thus, this model could be used to more accurately estimate the FST relative to estimates that only consider the air temperature. In addition, this model provides useful information for sunburn protection management.

  16. Novel surface treatment for hydrogen storage alloy in Ni/MH battery

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xiangyu; Ma, Liqun; Ding, Yi; Yang, Meng; Shen, Xiaodong [College of Materials Science and Engineering, Nanjing University of Technology, 5 Xinmofan Road, Nanjing 210009 (China)

    2009-05-15

    A novel surface treatment for the MlNi{sub 3.8}Co{sub 0.75}Mn{sub 0.4}Al{sub 0.2} (La-rich mischmetal) hydrogen storage alloy has been carried out by using an aqueous solution of HF and KF with a little addition of KBH{sub 4}. The results of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) showed that rough surface was formed and Al was partly dissolved into the solution after the treatment. The result of XPS indicated the formation of Ni{sub 3}B and LaF{sub 3} compounds on the alloy surface by the treatment. The probable chemical reaction mechanism for the surface treatment was introduced. The treatment resulted in significant improvements in the activation property, discharge capacity and cycle life of the alloy, especially the high rate dischargeability (HRD). The HRD of the treated alloy still remained 54.9% while that of the untreated one was only 15.1% at a discharge current density of 1200 mA/g. (author)

  17. Dynamic Wetting Behavior of Vibrated Droplets on a Micropillared Surface

    Directory of Open Access Journals (Sweden)

    Zhi-hai Jia

    2016-01-01

    Full Text Available The dynamical wetting behavior has been observed under vertical vibration of a water droplet placed on a micropillared surface. The wetting transition takes place under the different processes. In compression process, the droplet is transited from Cassie state to Wenzel state. The droplet undergoes a Wenzel-Cassie wetting transition in restoring process and the droplet bounces off from the surface in bouncing process. Meanwhile, the wetting and dewetting models during vibration are proposed. The wetting transition is confirmed by the model calculation. This study has potential to be used to control the wetting state.

  18. Assessing the Nano-Dynamics of the Cell Surface

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Chil Man [Dept. of Physiology and Biophysics, State University of New York, Buffalo (United States); Park, Ik Keun [Mechanical Engineering, Seoul National University of Technology, Seoul (Korea, Republic of); Bulter, Peter J. [Dept. of Bioengineering, The Pennsylvania State University, University Park (United States)

    2012-06-15

    It is important to know the mechanism of cell membrane fluctuation because it can be readout for the nanomechanical interaction between cytoskeleton and plasma membrane. Traditional techniques, however, have drawbacks such as probe contact with the cell surface, complicate analysis, and limit spatial and temporal resolution. In this study, we developed a new system for non-contact measurement of nano-scale localized-cell surface dynamics using modified-scanning ion-conductance microscopy. With 2 nm resolution, we determined that endothelial cells have local membrane fluctuations of -20 nm, actin depolymerization causes increase in fluctuation amplitude, and ATP depletion abolishes all membrane fluctuations.

  19. Dynamic Eigenvalue Problem of Concrete Slab Road Surface

    Science.gov (United States)

    Pawlak, Urszula; Szczecina, Michał

    2017-10-01

    The paper presents an analysis of the dynamic eigenvalue problem of concrete slab road surface. A sample concrete slab was modelled using Autodesk Robot Structural Analysis software and calculated with Finite Element Method. The slab was set on a one-parameter elastic subsoil, for which the modulus of elasticity was separately calculated. The eigen frequencies and eigenvectors (as maximal vertical nodal displacements) were presented. On the basis of the results of calculations, some basic recommendations for designers of concrete road surfaces were offered.

  20. Single-Particle Dynamics in Electron Storage Rings with Extremely Low Emittance

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yunhai; /SLAC

    2011-05-31

    Electron storage rings are widely used for high luminosity colliders, damping rings in high-energy linear colliders, and synchrotron light sources. They have become essential facilities to study high-energy physics and material and medical sciences. To further increase the luminosity of colliders or the brightness of synchrotron light sources, the beam emittance is being continually pushed downward, recently to the nanometer region. In the next decade, another order of reduction is expected. This requirement of ultra-low emittance presents many design challenges in beam dynamics, including better analysis of maps and improvement of dynamic apertures. To meet these challenges, we have refined transfer maps of common elements in storage rings and developed a new method to compute the resonance driving terms as they are built up along a beamline. The method is successfully applied to a design of PEP-X as a future light source with 100-pm emittance. As a result, we discovered many unexpected cancelations of the fourth-order resonance terms driven by sextupoles within an achromat.

  1. Dynamic response analysis of the LBL Advanced Light Source synchrotron radiation storage ring

    International Nuclear Information System (INIS)

    Leung, K.

    1993-05-01

    This paper presents the dynamic response analysis of the photon source synchrotron radiation storage ring excited by ground motion measured at the Lawrence Berkeley Laboratory advanced light source building site. The high spectral brilliance requirement the photon beams of the advanced light source storage ring specified displacement of the quadrupole focusing magnets in the order of 1 micron in vertical motion.There are 19 magnets supported by a 430-inch steel box beam girder. The girder and all magnets are supported by the kinematic mount system normally used in optical equipment. The kinematic mount called a six-strut magnet support system is now considered as an alternative system for supporting SSC magnets in the Super Collider. The effectively designed and effectively operated six-strut support system is now successfully operated for the Advanced Light Source (ALS) accelerator at the Lawrence Berkeley Laboratory. This paper will present the method of analysis and results of the dynamic motion study at the center of the magnets under the most critical excitation source as recorded at the LBL site

  2. Dynamics of the contact between a ruthenium surface with a single nanoasperity and a flat ruthenium surface: Molecular dynamics simulations

    International Nuclear Information System (INIS)

    Barros de Oliveira, Alan; Fortini, Andrea; Buldyrev, Sergey V.; Srolovitz, David

    2011-01-01

    We study the dynamics of the contact between a pair of surfaces (with properties designed to mimic ruthenium) via molecular dynamics simulations. In particular, we study the contact between a ruthenium surface with a single nanoasperity and a flat ruthenium surface. The results of such simulations suggest that contact behavior is highly variable. The goal of this study is to investigate the source and degree of this variability. We find that during compression, the behavior of the contact force displacement curves is reproducible, while during contact separation, the behavior is highly variable. Examination of the contact surfaces suggests that two separation mechanisms are in operation and give rise to this variability. One mechanism corresponds to the formation of a bridge between the two surfaces that plastically stretches as the surfaces are drawn apart and eventually separate in shear. This leads to a morphology after separation in which there are opposing asperities on the two surfaces. This plastic separation/bridge formation mechanism leads to a large work of separation. The other mechanism is a more brittle-like mode in which a crack propagates across the base of the asperity (slightly below the asperity/substrate junction) leading to most of the asperity on one surface or the other after separation and a slight depression facing this asperity on the opposing surface. This failure mode corresponds to a smaller work of separation. This failure mode corresponds to a smaller work of separation. Furthermore, contacts made from materials that exhibit predominantly brittle-like behavior will tend to require lower work of separation than those made from ductile-like contact materials.

  3. Dynamics and Instabilities of Free Surface and Vortex Flows

    DEFF Research Database (Denmark)

    Tophøj, Laust Emil Hjerrild

    2012-01-01

    This PhD thesis consists of two main parts. The first part describes the dynamics of an ideal fluid on a stationary free surface of a given shape. It turns out that one can formulate a set of self-contained equations of momentum conservation for the tangential flow, with no reference to the flow ......)]. Finally, an experimental work on elastic collisions of wet spheres is briefly discussed....

  4. Dynamic Surface Control and Its Application to Lateral Vehicle Control

    Directory of Open Access Journals (Sweden)

    Bongsob Song

    2014-01-01

    Full Text Available This paper extends the design and analysis methodology of dynamic surface control (DSC in Song and Hedrick, 2011, for a more general class of nonlinear systems. When rotational mechanical systems such as lateral vehicle control and robot control are considered for applications, sinusoidal functions are easily included in the equation of motions. If such a sinusoidal function is used as a forcing term for DSC, the stability analysis faces the difficulty due to highly nonlinear functions resulting from the low-pass filter dynamics. With modification of input variables to the filter dynamics, the burden of mathematical analysis can be reduced and stability conditions in linear matrix inequality form to guarantee the quadratic stability via DSC are derived for the given class of nonlinear systems. Finally, the proposed design and analysis approach are applied to lateral vehicle control for forward automated driving and backward parallel parking at a low speed as well as an illustrative example.

  5. Implementation of surface hopping molecular dynamics using semiempirical methods

    International Nuclear Information System (INIS)

    Fabiano, E.; Keal, T.W.; Thiel, W.

    2008-01-01

    A molecular dynamics driver and surface hopping algorithm for nonadiabatic dynamics has been implemented in a development version of the MNDO semiempirical electronic structure package. The required energies, gradients and nonadiabatic couplings are efficiently evaluated on the fly using semiempirical configuration interaction methods. The choice of algorithms for the time evolution of the nuclear motion and quantum amplitudes is discussed, and different schemes for the computation of nonadiabatic couplings are analysed. The importance of molecular orbital tracking and electronic state following is underlined in the context of configuration interaction calculations. The method is applied to three case studies (ethylene, methaniminium ion, and methanimine) using the orthogonalization corrected OM2 Hamiltonian. In all three cases decay times and dynamics paths similar to high-level ab initio results are obtained

  6. Memory effects in nonadiabatic molecular dynamics at metal surfaces

    DEFF Research Database (Denmark)

    Olsen, Thomas; Schiøtz, Jakob

    2010-01-01

    We study the effect of temporal correlation in a Langevin equation describing nonadiabatic dynamics at metal surfaces. For a harmonic oscillator, the Langevin equation preserves the quantum dynamics exactly and it is demonstrated that memory effects are needed in order to conserve the ground state...... energy of the oscillator. We then compare the result of Langevin dynamics in a harmonic potential with a perturbative master equation approach and show that the Langevin equation gives a better description in the nonperturbative range of high temperatures and large friction. Unlike the master equation......, this approach is readily extended to anharmonic potentials. Using density functional theory, we calculate representative Langevin trajectories for associative desorption of N-2 from Ru(0001) and find that memory effects lower the dissipation of energy. Finally, we propose an ab initio scheme to calculate...

  7. Evaporation dynamics of completely wetting drops on geometrically textured surfaces

    Science.gov (United States)

    Mekhitarian, Loucine; Sobac, Benjamin; Dehaeck, Sam; Haut, Benoît; Colinet, Pierre

    2017-10-01

    This study deals with the evaporation dynamics of completely wetting and highly volatile drops deposited on geometrically textured but chemically homogeneous surfaces. The texturation consists in a cylindrical pillars array with a square pitch. The triple line dynamics and the drop shape are characterized by an interferometric method. A parametric study is realized by varying the radius and the height of the pillars (at fixed interpillar distance), allowing to distinguish three types of dynamics: i) an evaporation-dominated regime with a receding triple line; ii) a spreading-dominated regime with an initially advancing triple line; iii) a cross-over region with strong pinning effects. The overall picture is in qualitative agreement with a mathematical model showing that the selected regime mostly depends on the value of a dimensionless parameter comparing the time scales for evaporation and spreading into the substrate texture.

  8. Atmospheric stability analysis over statically and dynamically rough surfaces

    Science.gov (United States)

    Maric, Emina; Metzger, Meredith; Singha, Arindam; Sadr, Reza

    2011-11-01

    The ratio of buoyancy flux to turbulent kinetic energy production in the atmospheric surface layer is investigated experimentally for air flow over two types of surfaces characterized by static and dynamic roughness. In this study, ``static'' refers to the time-invariant nature of naturally-occurring roughness over a mud/salt playa; while, ``dynamic'' refers to the behavior of water waves along an air-water interface. In both cases, time-resolved measurements of the momentum and heat fluxes were acquired from synchronized 3D sonic anemometers mounted on a vertical tower. Field campaigns were conducted at two sites, representing the ``statically'' and ``dynamically'' rough surfaces, respectively: (1) the SLTEST facility in Utah's western desert, and (2) the new Doha airport in Qatar under construction along the coast of the Persian Gulf. Note, at site 2, anemometers were located directly above the water by extension from a tower secured to the end of a 1 km-long pier. Comparisons of the Monin-Obukhov length, flux Richardson number, and gradient Richardson number are presented, and discussed in the context of the observed evolution of the turbulent spectra in response to diurnal variations of atmospheric stability. Supported by the Qatar National Research Fund.

  9. MRS [monitored retrievable storage] systems study Task G report: The role and functions of surface storage of radioactive material in the federal waste management system

    International Nuclear Information System (INIS)

    Wood, T.W.; Short, S.M.; Woodruff, M.G.; Altenhofen, M.K.; MacKay, C.A.

    1989-04-01

    This is one of nine studies undertaken by contractors to the US Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), to provide a technical basis for re-evaluating the role of a monitored retrievable storage (MRS) facility. The study investigates the functions that could be performed by surface storage of radioactive material within the federal radioactive waste management system, including enabling acceptance of spent fuel from utility owners, scheduling of waste-preparation processes within the system, enhancement of system operating reliability, and conditioning the thermal (decay heat) characteristics of spent fuel emplaced in a repository. The analysis focuses particularly on the effects of storage capacity and DOE acceptance schedule on power reactors. Figures of merit developed include the storage capacity [in metric tons of uranium (MTU)] required to be added beyond currently estimated maximum spent fuel storage capacities and its associated cost, and the number of years that spent fuel pools would remain open after last discharge (in pool-years) and the cost of this period of operation. 27 refs., 36 figs., 18 tabs

  10. Observation of dynamic water microadsorption on Au surface

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaokang, E-mail: xiaokang.huang@tqs.com; Gupta, Gaurav; Gao, Weixiang; Tran, Van; Nguyen, Bang; McCormick, Eric; Cui, Yongjie; Yang, Yinbao; Hall, Craig; Isom, Harold [TriQuint Semiconductor, Inc., 500 W Renner Road, Richardson, Texas 75080 (United States)

    2014-05-15

    Experimental and theoretical research on water wettability, adsorption, and condensation on solid surfaces has been ongoing for many decades because of the availability of new materials, new detection and measurement techniques, novel applications, and different scales of dimensions. Au is a metal of special interest because it is chemically inert, has a high surface energy, is highly conductive, and has a relatively high melting point. It has wide applications in semiconductor integrated circuitry, microelectromechanical systems, microfluidics, biochips, jewelry, coinage, and even dental restoration. Therefore, its surface condition, wettability, wear resistance, lubrication, and friction attract a lot of attention from both scientists and engineers. In this paper, the authors experimentally investigated Au{sub 2}O{sub 3} growth, wettability, roughness, and adsorption utilizing atomic force microscopy, scanning electron microscopy, reflectance spectrometry, and contact angle measurement. Samples were made using a GaAs substrate. Utilizing a super-hydrophilic Au surface and the proper surface conditions of the surrounding GaAs, dynamic microadsorption of water on the Au surface was observed in a clean room environment. The Au surface area can be as small as 12 μm{sup 2}. The adsorbed water was collected by the GaAs groove structure and then redistributed around the structure. A model was developed to qualitatively describe the dynamic microadsorption process. The effective adsorption rate was estimated by modeling and experimental data. Devices for moisture collection and a liquid channel can be made by properly arranging the wettabilities or contact angles of different materials. These novel devices will be very useful in microfluid applications or biochips.

  11. Biofilm attachment reduction on bioinspired, dynamic, micro-wrinkling surfaces

    International Nuclear Information System (INIS)

    Epstein, Alexander K; Hong, Donggyoon; Kim, Philseok; Aizenberg, Joanna

    2013-01-01

    Most bacteria live in multicellular communities known as biofilms that are adherent to surfaces in our environment, from sea beds to plumbing systems. Biofilms are often associated with clinical infections, nosocomial deaths and industrial damage such as bio-corrosion and clogging of pipes. As mature biofilms are extremely challenging to eradicate once formed, prevention is advantageous over treatment. However, conventional surface chemistry strategies are either generally transient, due to chemical masking, or toxic, as in the case of leaching marine antifouling paints. Inspired by the nonfouling skins of echinoderms and other marine organisms, which possess highly dynamic surface structures that mechanically frustrate bio-attachment, we have developed and tested a synthetic platform based on both uniaxial mechanical strain and buckling-induced elastomer microtopography. Bacterial biofilm attachment to the dynamic substrates was studied under an array of parameters, including strain amplitude and timescale (1–100 mm s −1 ), surface wrinkle length scale, bacterial species and cell geometry, and growth time. The optimal conditions for achieving up to ∼ 80% Pseudomonas aeruginosa biofilm reduction after 24 h growth and ∼ 60% reduction after 48 h were combinatorially elucidated to occur at 20% strain amplitude, a timescale of less than ∼ 5 min between strain cycles and a topography length scale corresponding to the cell dimension of ∼ 1 μm. Divergent effects on the attachment of P. aeruginosa, Staphylococcus aureus and Escherichia coli biofilms showed that the dynamic substrate also provides a new means of species-specific biofilm inhibition, or inversely, selection for a desired type of bacteria, without reliance on any toxic or transient surface chemical treatments. (paper)

  12. Biofilm attachment reduction on bioinspired, dynamic, micro-wrinkling surfaces

    Science.gov (United States)

    Epstein, Alexander K.; Hong, Donggyoon; Kim, Philseok; Aizenberg, Joanna

    2013-09-01

    Most bacteria live in multicellular communities known as biofilms that are adherent to surfaces in our environment, from sea beds to plumbing systems. Biofilms are often associated with clinical infections, nosocomial deaths and industrial damage such as bio-corrosion and clogging of pipes. As mature biofilms are extremely challenging to eradicate once formed, prevention is advantageous over treatment. However, conventional surface chemistry strategies are either generally transient, due to chemical masking, or toxic, as in the case of leaching marine antifouling paints. Inspired by the nonfouling skins of echinoderms and other marine organisms, which possess highly dynamic surface structures that mechanically frustrate bio-attachment, we have developed and tested a synthetic platform based on both uniaxial mechanical strain and buckling-induced elastomer microtopography. Bacterial biofilm attachment to the dynamic substrates was studied under an array of parameters, including strain amplitude and timescale (1-100 mm s-1), surface wrinkle length scale, bacterial species and cell geometry, and growth time. The optimal conditions for achieving up to ˜ 80% Pseudomonas aeruginosa biofilm reduction after 24 h growth and ˜ 60% reduction after 48 h were combinatorially elucidated to occur at 20% strain amplitude, a timescale of less than ˜ 5 min between strain cycles and a topography length scale corresponding to the cell dimension of ˜ 1 μm. Divergent effects on the attachment of P. aeruginosa, Staphylococcus aureus and Escherichia coli biofilms showed that the dynamic substrate also provides a new means of species-specific biofilm inhibition, or inversely, selection for a desired type of bacteria, without reliance on any toxic or transient surface chemical treatments.

  13. Use of artificial barriers in a site for surface storage of radioactive waste

    International Nuclear Information System (INIS)

    Gros, J.C.; Madoz-Escande, C.; Metivier, J.M.; Grimaud, P.

    1990-01-01

    The objective is the on site study of the influence of an injection screen on the flow in a water table of a porous medium, in order to improve the safety of a surface radioactive waste storage site. A hydrodispersive study has provided information for the definition of the role of the screen: the transfer times of the pollutant in the water table are increased by a factor of 2 and, in comparison, the concentration are clearly reduced by a factor of 10. The implantation of an injection screen in the ground should result in an improvement in the restrictive quality of the barrier and the contamination of an aquifer should be slower without interruption to the flow

  14. Condensation and Wetting Dynamics on Micro/Nano-Structured Surfaces

    Science.gov (United States)

    Olceroglu, Emre

    -condensable gases (NCGs), a novel characterization technique has been developed based on image tracking of droplet growth rates. The full-field dynamic characterization of superhydrophobic surfaces during condensation has been achieved using high-speed microscopy coupled with image-processing algorithms. This method is able to resolve heat fluxes as low as 20 W/m 2 and heat transfer coefficients of up to 1000 kW/m2, across an array of 1000's of microscale droplets simultaneously. Nanostructured surfaces with mixed wettability have been used to demonstrate delayed flooding during superhydrophobic condensation. These surfaces have been optimized and characterized using optical and electron microscopy, leading to the observation of self-organizing microscale droplets. The self-organization of small droplets effectively delays the onset of surface flooding, allowing the superhydrophobic surfaces to operate at higher supersaturations. Additionally, hierarchical surfaces have been fabricated and characterized showing enhanced droplet growth rates as compared to existing models. This enhancement has been shown to be derived from the presence of small feeder droplets nucleating within the microscale unit cells of the hierarchical surfaces. Based on the experimental observations, a mechanistic model for growth rates has been developed for superhydrophobic hierarchical surfaces. While superhydrophobic surfaces exhibit high heat transfer rates they are inherently unstable due to the necessity to maintain a non-wetted state in a condensing environment. As an alternative condensation surface, a novel design is introduced here using ambiphilic structures to promote the formation of a thin continuous liquid film across the surface which can still provide the benefits of superhydrophobic condensation. Preliminary results show that the ambiphilic structures restrain the film thickness, thus maintaining a low thermal resistance while simultaneously maximizing the liquid-vapor interface available for

  15. Satellite-based estimates of surface water dynamics in the Congo River Basin

    Science.gov (United States)

    Becker, M.; Papa, F.; Frappart, F.; Alsdorf, D.; Calmant, S.; da Silva, J. Santos; Prigent, C.; Seyler, F.

    2018-04-01

    In the Congo River Basin (CRB), due to the lack of contemporary in situ observations, there is a limited understanding of the large-scale variability of its present-day hydrologic components and their link with climate. In this context, remote sensing observations provide a unique opportunity to better characterize those dynamics. Analyzing the Global Inundation Extent Multi-Satellite (GIEMS) time series, we first show that surface water extent (SWE) exhibits marked seasonal patterns, well distributed along the major rivers and their tributaries, and with two annual maxima located: i) in the lakes region of the Lwalaba sub-basin and ii) in the "Cuvette Centrale", including Tumba and Mai-Ndombe Lakes. At an interannual time scale, we show that SWE variability is influenced by ENSO and the Indian Ocean dipole events. We then estimate water level maps and surface water storage (SWS) in floodplains, lakes, rivers and wetlands of the CRB, over the period 2003-2007, using a multi-satellite approach, which combines the GIEMS dataset with the water level measurements derived from the ENVISAT altimeter heights. The mean annual variation in SWS in the CRB is 81 ± 24 km3 and contributes to 19 ± 5% of the annual variations of GRACE-derived terrestrial water storage (33 ± 7% in the Middle Congo). It represents also ∼6 ± 2% of the annual water volume that flows from the Congo River into the Atlantic Ocean.

  16. The effects of the pedestal/floor interface on the dynamic characteristics of the storage ring girder support assemblies

    International Nuclear Information System (INIS)

    Jendrzejczyk, J.A.; Chen, S.S.; Zhu, S.; Mangra, D.; Smith, R.K.

    1993-05-01

    To avoid unacceptable vibration of the storage ring quadrupoles, and to ensure that the established vibration criteria are satisfied, the philosophy from inception of the APS has been (1) to locate and design the machine to minimize motion of the storage ring basemat and, (2) following construction, to monitor machine operation and user experiments to ensure that vibration sources are not introduced. This report addresses the design of the storage ring girder support assemblies, and, specifically, the effect of the pedestal/floor interface on the dynamic characteristics (i.e., resonant frequencies, damping, and mode shape)

  17. DYNAMIC SURFACE BOUNDARY-CONDITIONS - A SIMPLE BOUNDARY MODEL FOR MOLECULAR-DYNAMICS SIMULATIONS

    NARCIS (Netherlands)

    JUFFER, AH; BERENDSEN, HJC

    1993-01-01

    A simple model for the treatment of boundaries in molecular dynamics simulations is presented. The method involves the positioning of boundary atoms on a surface that surrounds a system of interest. The boundary atoms interact with the inner region and represent the effect of atoms outside the

  18. Dynamical investigation and parameter stability region analysis of a flywheel energy storage system in charging mode

    International Nuclear Information System (INIS)

    Zhang Wei-Ya; Li Yong-Li; Chang Xiao-Yong; Wang Nan

    2013-01-01

    In this paper, the dynamic behavior analysis of the electromechanical coupling characteristics of a flywheel energy storage system (FESS) with a permanent magnet (PM) brushless direct-current (DC) motor (BLDCM) is studied. The Hopf bifurcation theory and nonlinear methods are used to investigate the generation process and mechanism of the coupled dynamic behavior for the average current controlled FESS in the charging mode. First, the universal nonlinear dynamic model of the FESS based on the BLDCM is derived. Then, for a 0.01 kWh/1.6 kW FESS platform in the Key Laboratory of the Smart Grid at Tianjin University, the phase trajectory of the FESS from a stable state towards chaos is presented using numerical and stroboscopic methods, and all dynamic behaviors of the system in this process are captured. The characteristics of the low-frequency oscillation and the mechanism of the Hopf bifurcation are investigated based on the Routh stability criterion and nonlinear dynamic theory. It is shown that the Hopf bifurcation is directly due to the loss of control over the inductor current, which is caused by the system control parameters exceeding certain ranges. This coupling nonlinear process of the FESS affects the stability of the motor running and the efficiency of energy transfer. In this paper, we investigate into the effects of control parameter change on the stability and the stability regions of these parameters based on the averaged-model approach. Furthermore, the effect of the quantization error in the digital control system is considered to modify the stability regions of the control parameters. Finally, these theoretical results are verified through platform experiments. (interdisciplinary physics and related areas of science and technology)

  19. Antiferroelectric polarization switching and dynamic scaling of energy storage: A Monte Carlo simulation

    Science.gov (United States)

    Huang, B. Y.; Lu, Z. X.; Zhang, Y.; Xie, Y. L.; Zeng, M.; Yan, Z. B.; Liu, J.-M.

    2016-05-01

    The polarization-electric field hysteresis loops and the dynamics of polarization switching in a two-dimensional antiferroelectric (AFE) lattice submitted to a time-oscillating electric field E(t) of frequency f and amplitude E0, is investigated using Monte Carlo simulation based on the Landau-Devonshire phenomenological theory on antiferroelectrics. It is revealed that the AFE double-loop hysteresis area A, i.e., the energy loss in one cycle of polarization switching, exhibits the single-peak frequency dispersion A(f), suggesting the unique characteristic time for polarization switching, which is independent of E0 as long as E0 is larger than the quasi-static coercive field for the antiferroelectric-ferroelectric transitions. However, the dependence of recoverable stored energy W on amplitude E0 seems to be complicated depending on temperature T and frequency f. A dynamic scaling behavior of the energy loss dispersion A(f) over a wide range of E0 is obtained, confirming the unique characteristic time for polarization switching of an AFE lattice. The present simulation may shed light on the dynamics of energy storage and release in AFE thin films.

  20. Dynamic Outsourced Proofs of Retrievability Enabling Auditing Migration for Remote Storage Security

    Directory of Open Access Journals (Sweden)

    Lu Rao

    2018-01-01

    Full Text Available Remote data auditing service is important for mobile clients to guarantee the intactness of their outsourced data stored at cloud side. To relieve mobile client from the nonnegligible burden incurred by performing the frequent data auditing, more and more literatures propose that the execution of such data auditing should be migrated from mobile client to third-party auditor (TPA. However, existing public auditing schemes always assume that TPA is reliable, which is the potential risk for outsourced data security. Although Outsourced Proofs of Retrievability (OPOR have been proposed to further protect against the malicious TPA and collusion among any two entities, the original OPOR scheme applies only to the static data, which is the limitation that should be solved for enabling data dynamics. In this paper, we design a novel authenticated data structure called bv23Tree, which enables client to batch-verify the indices and values of any number of appointed leaves all at once for efficiency. By utilizing bv23Tree and a hierarchical storage structure, we present the first solution for Dynamic OPOR (DOPOR, which extends the OPOR model to support dynamic updates of the outsourced data. Extensive security and performance analyses show the reliability and effectiveness of our proposed scheme.

  1. [Dynamic changes of surface soil organic carbon and light-fraction organic carbon after mobile dune afforestation with Mongolian pine in Horqin Sandy Land].

    Science.gov (United States)

    Shang, Wen; Li, Yu-qiang; Wang, Shao-kun; Feng, Jing; Su, Na

    2011-08-01

    This paper studied the dynamic changes of surface (0-15 cm) soil organic carbon (SOC) and light-fraction organic carbon (LFOC) in 25- and 35-year-old sand-fixing Mongolian pine (Pinus sylvestris var. mongolica) plantations in Horqin Sandy Land, with a mobile dune as a comparison site. After the afforestation on mobile dune, the content of coarse sand in soil decreased, while that of fine sand and clay-silt increased significantly. The SOC and LFOC contents also increased significantly, but tended to decrease with increasing soil depth. Afforestation increased the storages of SOC and LFOC in surface soil, and the increment increased with plantation age. In the two plantations, the increment of surface soil LFOC storage was much higher than that of SOC storage, suggesting that mobile dune afforestation had a larger effect on surface soil LFOC than on SOC.

  2. Dynamics and diffusive-conformational coupling in polymer bulk samples and surfaces: a molecular dynamics study

    International Nuclear Information System (INIS)

    Vree, C; Mayr, S G

    2010-01-01

    The impact of free surfaces on the mobility and conformational fluctuations of model polymer chains is investigated with the help of classical molecular dynamics simulations over a broad temperature range. Below a critical temperature, T*, similar to the critical temperature of the mode coupling theory, the center-of-mass displacements and temporal fluctuations of the radius of gyration of individual chains-as a fingerprint of structural reconfigurations-reveal a strong enhancement close to surfaces, while this effect diminishes with increasing temperature and observation time. Interpreting conformational fluctuations as a random walk in conformational space, identical activation enthalpies for structural reconfigurations and diffusion are obtained within the error bars in the bulk and at the surfaces, thus indicating a coupling of diffusive and conformational dynamics.

  3. Dynamic Corneal Surface Mapping with Electronic Speckle Pattern Interferometry

    Science.gov (United States)

    Iqbal, S.; Gualini, M. M. S.

    2013-06-01

    In view of the fast advancement in ophthalmic technology and corneal surgery, there is a strong need for the comprehensive mapping and characterization techniques for corneal surface. Optical methods with precision non-contact approaches have been found to be very useful for such bio measurements. Along with the normal mapping approaches, elasticity of corneal surface has an important role in its characterization and needs to be appropriately measured or estimated for broader diagnostics and better prospective surgical results, as it has important role in the post-op corneal surface reconstruction process. Use of normal corneal topographic devices is insufficient for any intricate analysis since these devices operate at relatively moderate resolution. In the given experiment, Pulsed Electronic Speckle Pattern Interferometry has been utilized along with an excitation mechanism to measure the dynamic response of the sample cornea. A Pulsed ESPI device has been chosen for the study because of its micron-level resolution and other advantages in real-time deformation analysis. A bovine cornea has been used as a sample in the subject experiment. The dynamic response has been taken on a chart recorder and it is observed that it does show a marked deformation at a specific excitation frequency, which may be taken as a characteristic elasticity parameter for the surface of that corneal sample. It was seen that outside resonance conditions the bovine cornea was not that much deformed. Through this study, the resonance frequency and the corresponding corneal deformations are mapped and plotted in real time. In these experiments, data was acquired and processed by FRAMES plus computer analysis system. With some analysis of the results, this technique can help us to refine a more detailed corneal surface mathematical model and some preliminary work was done on this. Such modelling enhancements may be useful for finer ablative surgery planning. After further experimentation

  4. An Optimization Method for Virtual Globe Ocean Surface Dynamic Visualization

    Directory of Open Access Journals (Sweden)

    HUANG Wumeng

    2016-12-01

    Full Text Available The existing visualization method in the virtual globe mainly uses the projection grid to organize the ocean grid. This special grid organization has the defects in reflecting the difference characteristics of different ocean areas. The method of global ocean visualization based on global discrete grid can make up the defect of the projection grid method by matching with the discrete space of the virtual globe, so it is more suitable for the virtual ocean surface simulation application.But the available global discrete grids method has many problems which limiting its application such as the low efficiency of rendering and loading, the need of repairing grid crevices. To this point, we propose an optimization for the global discrete grids method. At first, a GPU-oriented multi-scale grid model of ocean surface which develops on the foundation of global discrete grids was designed to organize and manage the ocean surface grids. Then, in order to achieve the wind-drive wave dynamic rendering, this paper proposes a dynamic wave rendering method based on the multi-scale ocean surface grid model to support real-time wind field updating. At the same time, considering the effect of repairing grid crevices on the system efficiency, this paper presents an efficient method for repairing ocean surface grid crevices based on the characteristics of ocean grid and GPU technology. At last, the feasibility and validity of the method are verified by the comparison experiment. The experimental results show that the proposed method is efficient, stable and fast, and can compensate for the lack of function of the existing methods, so the application range is more extensive.

  5. Vibro Replacement, Dynamic Compaction, and Vibro Compaction case histories for petroleum storage tank facilities

    Energy Technology Data Exchange (ETDEWEB)

    Beaton, N; Scott, J. [Geopac West Ltd., Richmond, BC (Canada)

    2010-07-01

    This paper discussed approaches to tank farm ground improvement via 3 Canadian ground improvement case histories in order to set forth the advantages of ground improvement for foundation support at petroleum storage tank facilities. Each case study featured a particular set of site conditions, performance criteria, and ground improvement techniques selected to attain the desired foundation performance. The first case study involved a Vibro Replacement stone column to meet strict seismicity requirements, the second employed Dynamic Compaction to mitigate deep variable fill within a former gravel pit, and the last encompassed Vibro Compaction applied to a site with a sand fill soil profile. The site conditions, the design requirements, the ground improvement solution, the execution, and the quality control techniques and results were presented for each case history. Soil reinforcement and ground improvement to treat loose and soft soils below heavy storage tanks can be an economical solution to foundation design challenges. However, it is important to select proper methods and tailor the densification programs to the specific subsoil conditions and design requirements. In each application, the selected ground improvement technique exceeded the specified in-situ testing requirements. 3 refs., 9 figs.

  6. Flow and Residence Times of Dynamic River Bank Storage and Sinuosity-Driven Hyporheic Exchange

    Science.gov (United States)

    Gomez-Velez, J. D.; Wilson, J. L.; Cardenas, M. B.; Harvey, J. W.

    2017-10-01

    Hydrologic exchange fluxes (HEFs) vary significantly along river corridors due to spatiotemporal changes in discharge and geomorphology. This variability results in the emergence of biogeochemical hot-spots and hot-moments that ultimately control solute and energy transport and ecosystem services from the local to the watershed scales. In this work, we use a reduced-order model to gain mechanistic understanding of river bank storage and sinuosity-driven hyporheic exchange induced by transient river discharge. This is the first time that a systematic analysis of both processes is presented and serves as an initial step to propose parsimonious, physics-based models for better predictions of water quality at the large watershed scale. The effects of channel sinuosity, alluvial valley slope, hydraulic conductivity, and river stage forcing intensity and duration are encapsulated in dimensionless variables that can be easily estimated or constrained. We find that the importance of perturbations in the hyporheic zone's flux, residence times, and geometry is mainly explained by two-dimensionless variables representing the ratio of the hydraulic time constant of the aquifer and the duration of the event (Γd) and the importance of the ambient groundwater flow (Δh∗). Our model additionally shows that even systems with small sensitivity, resulting in small changes in the hyporheic zone extent, are characterized by highly variable exchange fluxes and residence times. These findings highlight the importance of including dynamic changes in hyporheic zones for typical HEF models such as the transient storage model.

  7. Privacy-Preserving Outsourced Auditing Scheme for Dynamic Data Storage in Cloud

    Directory of Open Access Journals (Sweden)

    Tengfei Tu

    2017-01-01

    Full Text Available As information technology develops, cloud storage has been widely accepted for keeping volumes of data. Remote data auditing scheme enables cloud user to confirm the integrity of her outsourced file via the auditing against cloud storage, without downloading the file from cloud. In view of the significant computational cost caused by the auditing process, outsourced auditing model is proposed to make user outsource the heavy auditing task to third party auditor (TPA. Although the first outsourced auditing scheme can protect against the malicious TPA, this scheme enables TPA to have read access right over user’s outsourced data, which is a potential risk for user data privacy. In this paper, we introduce the notion of User Focus for outsourced auditing, which emphasizes the idea that lets user dominate her own data. Based on User Focus, our proposed scheme not only can prevent user’s data from leaking to TPA without depending on data encryption but also can avoid the use of additional independent random source that is very difficult to meet in practice. We also describe how to make our scheme support dynamic updates. According to the security analysis and experimental evaluations, our proposed scheme is provably secure and significantly efficient.

  8. The role of reconsolidation and the dynamic process of long-term memory formation and storage

    Directory of Open Access Journals (Sweden)

    Cristina M Alberini

    2011-03-01

    Full Text Available It is becoming increasingly clear that the processes of memory formation and storage are exquisitely dynamic. Elucidating the nature and temporal evolution of the biological changes that accompany encoding, storage and retrieval is key to understand memory formation. For explicit or medial temporal lobe-dependent memories that form after a discrete event and are stored for a long time, the physical changes underlying the encoding and processing of the information (memory trace or engram remain in a fragile state for some time. However, over time, the new memory becomes increasingly resistant to disruption until it is consolidated. Retrieval or reactivation of an apparently consolidated memory can render the memory labile again, and reconsolidation is the process that occurs to mediate its restabilization. Reconsolidation also evolves with the age of the memory: Young memories are sensitive to postreactivation disruption, but older memories are more resistant. Why does a memory become labile again if it is retrieved or reactivated? Here I suggest that the main function of reconsolidation is to contribute to the lingering consolidation process and mediate memory strengthening. I also discuss the literature and results regarding the influence of the passage of time on the reconsolidation of memory. These points have important implications for the use of reconsolidation in therapeutic settings.

  9. Normal form analysis of linear beam dynamics in a coupled storage ring

    International Nuclear Information System (INIS)

    Wolski, Andrzej; Woodley, Mark D.

    2004-01-01

    The techniques of normal form analysis, well known in the literature, can be used to provide a straightforward characterization of linear betatron dynamics in a coupled lattice. Here, we consider both the beam distribution and the betatron oscillations in a storage ring. We find that the beta functions for uncoupled motion generalize in a simple way to the coupled case. Defined in the way that we propose, the beta functions remain well behaved (positive and finite) under all circumstances, and have essentially the same physical significance for the beam size and betatron oscillation amplitude as in the uncoupled case. Application of this analysis to the online modeling of the PEP-II rings is also discussed

  10. Random Linear Network Coding is Key to Data Survival in Highly Dynamic Distributed Storage

    DEFF Research Database (Denmark)

    Sipos, Marton A.; Fitzek, Frank; Roetter, Daniel Enrique Lucani

    2015-01-01

    Distributed storage solutions have become widespread due to their ability to store large amounts of data reliably across a network of unreliable nodes, by employing repair mechanisms to prevent data loss. Conventional systems rely on static designs with a central control entity to oversee...... and control the repair process. Given the large costs for maintaining and cooling large data centers, our work proposes and studies the feasibility of a fully decentralized systems that can store data even on unreliable and, sometimes, unavailable mobile devices. This imposes new challenges on the design...... as the number of available nodes varies greatly over time and keeping track of the system's state becomes unfeasible. As a consequence, conventional erasure correction approaches are ill-suited for maintaining data integrity. In this highly dynamic context, random linear network coding (RLNC) provides...

  11. Effects of errors on the dynamic aperture of the Advanced Photon Source storage ring

    International Nuclear Information System (INIS)

    Bizek, H.; Crosbie, E.; Lessner, E.; Teng, L.; Wirsbinski, J.

    1991-01-01

    The individual tolerance limits for alignment errors and magnet fabrication errors in the 7-GeV Advanced Photon Source storage ring are determined by computer-simulated tracking. Limits are established for dipole strength and roll errors, quadrupole strength and alignment errors, sextupole strength and alignment errors, as well as higher order multipole strengths in dipole and quadrupole magnets. The effects of girder misalignments on the dynamic aperture are also studied. Computer simulations are obtained with the tracking program RACETRACK, with errors introduced from a user-defined Gaussian distribution, truncated at ±5 standard deviation units. For each error, the average and rms spread of the stable amplitudes are determined for ten distinct machines, defined as ten different seeds to the random distribution, and for five distinct initial directions of the tracking particle. 4 refs., 4 figs., 1 tab

  12. Molecular Dynamics Simulations of Water Droplets On Hydrophilic Silica Surfaces

    DEFF Research Database (Denmark)

    Zambrano, Harvey A; Walther, Jens Honore; Jaffe, Richard L.

    2009-01-01

    and DNA microarrays technologies.Although extensive experimental, theoretical and computational work has been devoted to study the nature of the interaction between silica and water, at the molecular level a complete understanding of silica-water systems has not been reached. Contact angle computations...... dynamics (MD) simulations of a hydrophilic air-water-silica system using the MD package FASTTUBE. We employ quantum chemistry calculation to obtain air-silica interaction parameters for the simulations. Our simulations are based in the following force fields: i) The silica-silica interaction is based...... of water droplets on silica surfaces offers a useful fundamental and quantitative measurement in order to study chemical and physical properties of water-silica systems. For hydrophobic systems the static and dynamic properties of the fluid-solid interface are influenced by the presence of air. Hence...

  13. Reactive surface organometallic complexes observed using dynamic nuclear polarization surface enhanced NMR spectroscopy

    KAUST Repository

    Pump, Eva; Viger-Gravel, Jasmine; Abou-Hamad, Edy; Samantaray, Manoja; Hamzaoui, Bilel; Gurinov, Andrei; Anjum, Dalaver H.; Gajan, David; Lesage, Anne; Bendjeriou-Sedjerari, Anissa; Emsley, Lyndon; Basset, Jean-Marie

    2016-01-01

    Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) is an emerging technique that allows access to high-sensitivity NMR spectra from surfaces. However, DNP SENS usually requires the use of radicals as an exogenous source of polarization, which has so far limited applications for organometallic surface species to those that do not react with the radicals. Here we show that reactive surface species can be studied if they are immobilized inside porous materials with suitably small windows, and if bulky nitroxide bi-radicals (here TEKPol) are used as the polarization source and which cannot enter the pores. The method is demonstrated by obtaining significant DNP enhancements from highly reactive complelxes [(equivalent to Si-O-)W(Me)(5)] supported on MCM-41, and effects of pore size (6.0, 3.0 and 2.5 nm) on the performance are discussed.

  14. Reactive surface organometallic complexes observed using dynamic nuclear polarization surface enhanced NMR spectroscopy

    KAUST Repository

    Pump, Eva

    2016-08-15

    Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) is an emerging technique that allows access to high-sensitivity NMR spectra from surfaces. However, DNP SENS usually requires the use of radicals as an exogenous source of polarization, which has so far limited applications for organometallic surface species to those that do not react with the radicals. Here we show that reactive surface species can be studied if they are immobilized inside porous materials with suitably small windows, and if bulky nitroxide bi-radicals (here TEKPol) are used as the polarization source and which cannot enter the pores. The method is demonstrated by obtaining significant DNP enhancements from highly reactive complelxes [(equivalent to Si-O-)W(Me)(5)] supported on MCM-41, and effects of pore size (6.0, 3.0 and 2.5 nm) on the performance are discussed.

  15. Surface treatment for hydrogen storage alloy of nickel/metal hydride battery

    Energy Technology Data Exchange (ETDEWEB)

    Wu, M.-S.; Wu, H.-R.; Wang, Y.-Y.; Wan, C.-C. [National Tsing Hua Univ., Hsinchu (Taiwan). Dept. of Chemical Engineering

    2000-04-28

    The electrochemical performance of AB{sub 2}-type (Ti{sub 0.35}Zr{sub 0.65}Ni{sub 1.2}V{sub 0.6}Mn{sub 0.2}Cr{sub 0.2}) and AB{sub 5}-type (MmB{sub 4.3}(Al{sub 0.3}Mn{sub 0.4}){sub 0.5}) hydrogen storage alloys modified by hot KOH etching and electroless nickel coating has been investigated. It is found that the alloy modified with hot KOH solution shows quick activation but at the expense of cycle-life stability. The alloy coated with nickel was effectively improved in both cycle-life stability and discharge capacity. Both the exchange and limiting current densities were increased by modifying the alloys by hot KOH solution dipping or electroless nickel coating as compared with untreated alloy electrode. The electrode with higher exchange current density and limiting current density leads to increased high-rate dischargeability. A duplex surface modified alloy (i.e., alloy first treated with hot KOH solution and then coated with nickel) has been developed, which performs satisfactorily with respect to both quick activation and long cycle life. In addition, the high-rate dischargeability for the electrode with duplex surface modification is superior to that of electrode solely treated with KOH etching or Ni plating. (orig.)

  16. Effect of two storage solutions on surface topography of two root-end fillings.

    Science.gov (United States)

    Asgary, Saeed; Eghbal, Mohammad Jafar; Parirokh, Masoud; Ghoddusi, Jamileh

    2009-12-01

    The effect of different storage solutions on surface topography of mineral trioxide aggregate (MTA) and new experimental cement (NEC) as root-end fillings was investigated. Twenty-four single-rooted teeth were cleaned, shaped and obturated in a same manner. After root-end resection, 3-mm deep root-end cavities were ultrasonically prepared. Samples were randomly divided into four test groups (A1-A2-B1-B2, n = 6). Root-end cavities in groups A and B were filled with MTA and NEC, respectively, and were then stored in 100% humidity for 24 h. The samples of groups 1 and 2 were, respectively, immersed in normal saline (NS) and phosphate buffer saline solutions for 1 week. The samples were imaged under stereomicroscope before and after immersion and were then investigated and analysed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA). Results showed significant difference among studied groups. Surface topography of all samples was altered by crystal formation and precipitation on root-end fillings except for group A1 (MTA-NS). SEM and EDXA results showed that the composition and structure of precipitated crystals were comparable with that of standard hydroxyapatite. It was concluded that biocompatibility, sealing ability, and cementogenic activity of MTA and probably NEC may be attributed to this fundamental bioactive reaction.

  17. Molecular Dynamics Simulations of Water Nanodroplets on Silica Surfaces

    DEFF Research Database (Denmark)

    Zambrano, Harvey A; Walther, Jens Honore; Jaffe, Richard L.

    2009-01-01

    and DNA microarrays technologies.4,5,6,7,8 Although extensive experimental, theoretical and computational work has been devoted to study the nature of the interaction between silica and water,2,9-16 at the molecular level a complete understanding of silica-water systems has not been reached. Contact angle...... computations of water droplets on silica surfaces offers a useful fundamental and quantitative measurement in order to study chemical and physical properties of water-silica systems.3,16,17,18 For hydrophobic systems the static and dynamic properties of the fluid-solid interface are influenced by the presence...

  18. Dynamic growth of slip surfaces in catastrophic landslides.

    Science.gov (United States)

    Germanovich, Leonid N; Kim, Sihyun; Puzrin, Alexander M

    2016-01-01

    This work considers a landslide caused by the shear band that emerges along the potential slip (rupture) surface. The material above the band slides downwards, causing the band to grow along the slope. This growth may first be stable (progressive), but eventually becomes dynamic (catastrophic). The landslide body acquires a finite velocity before it separates from the substrata. The corresponding initial-boundary value problem for a dynamic shear band is formulated within the framework of Palmer & Rice's ( Proc. R. Soc. Lond. A 332 , 527-548. (doi:10.1098/rspa.1973.0040)) approach, which is generalized to the dynamic case. We obtain the exact, closed-form solution for the band velocity and slip rate. This solution assesses when the slope fails owing to a limiting condition near the propagating tip of the shear band. Our results are applicable to both submarine and subaerial landslides of this type. It appears that neglecting dynamic (inertia) effects can lead to a significant underestimation of the slide size, and that the volumes of catastrophic slides can exceed the volumes of progressive slides by nearly a factor of 2. As examples, we consider the Gaviota and Humboldt slides offshore of California, and discuss landslides in normally consolidated sediments and sensitive clays. In particular, it is conceivable that Humboldt slide is unfinished and may still displace a large volume of sediments, which could generate a considerable tsunami. We show that in the case of submarine slides, the effect of water resistance on the shear band dynamics may frequently be limited during the slope failure stage. For a varying slope angle, we formulate a condition of slide cessation.

  19. Molecular Dynamics Simulations of Slip on Curved Surfaces

    Directory of Open Access Journals (Sweden)

    Ross D.A.

    2016-07-01

    Full Text Available We present Molecular Dynamics (MD simulations of liquid water confined within nanoscale geometries, including slit-like and cylindrical graphitic pores. These equilibrium results are used for calculating friction coefficients, which in turn can be used to calculate slip lengths. The slip length is a material property independent of the fluid flow rate. It is therefore a better quantity for study than the fluid velocity at the wall, also known as the slip velocity. Once the slip length has been found as a function of surface curvature, it can be used to parameterise Lattice Boltzmann (LB simulations. These larger scale simulations are able to tell us about how fluid transport is affected by slip in complex geometries; not just limited to single pores. Applications include flow and transport in nano-porous engine valve deposits and gas shales. The friction coefficient is found to be a function of curvature and is higher for fluid on convex surfaces and lower for concave surfaces. Both concave and convex surfaces approach the same value of the friction coefficient, which is constant above some critical radius of curvature, here found to be 7.4 ± 2.9 nm. The constant value of the friction coefficient is 10,000 ± 600 kg m−2 s−1, which is equivalent to a slip length of approximately 67 ± 4 nm.

  20. A scanning fluid dynamic gauging technique for probing surface layers

    International Nuclear Information System (INIS)

    Gordon, Patrick W; Chew, Y M John; Wilson, D Ian; Brooker, Anju D M; York, David W

    2010-01-01

    Fluid dynamic gauging (FDG) is a technique for measuring the thickness of soft solid deposit layers immersed in a liquid environment, in situ and in real time. This paper details the performance of a novel automated, scanning FDG probe (sFDG) which allows the thickness of a sample layer to be monitored at several points during an experiment, with a resolution of ±5 µm. Its application is demonstrated using layers of gelatine, polyvinyl alcohol (PVA) and baked tomato purée deposits. Swelling kinetics, as well as deformation behaviour—based on knowledge of the stresses imposed on the surface by the gauging flow—can be determined at several points, affording improved experimental data. The use of FDG as a surface scanning technique, operating as a fluid mechanical analogue of atomic force microscopy on a millimetre length scale, is also demonstrated. The measurement relies only on the flow behaviour, and is thus suitable for use in opaque fluids, does not contact the surface itself and does not rely on any specific physical properties of the surface, provided it is locally stiff

  1. Can foot anthropometric measurements predict dynamic plantar surface contact area?

    Directory of Open Access Journals (Sweden)

    Collins Natalie

    2009-10-01

    Full Text Available Abstract Background Previous studies have suggested that increased plantar surface area, associated with pes planus, is a risk factor for the development of lower extremity overuse injuries. The intent of this study was to determine if a single or combination of foot anthropometric measures could be used to predict plantar surface area. Methods Six foot measurements were collected on 155 subjects (97 females, 58 males, mean age 24.5 ± 3.5 years. The measurements as well as one ratio were entered into a stepwise regression analysis to determine the optimal set of measurements associated with total plantar contact area either including or excluding the toe region. The predicted values were used to calculate plantar surface area and were compared to the actual values obtained dynamically using a pressure sensor platform. Results A three variable model was found to describe the relationship between the foot measures/ratio and total plantar contact area (R2 = 0.77, p R2 = 0.76, p Conclusion The results of this study indicate that the clinician can use a combination of simple, reliable, and time efficient foot anthropometric measurements to explain over 75% of the plantar surface contact area, either including or excluding the toe region.

  2. Methane oxidation in pig and cattle slurry storages, and effects of surface crust moisture and methane availability

    DEFF Research Database (Denmark)

    Petersen, S.O.; Ambus, P.

    2006-01-01

    Storages with liquid manure (slurry) may develop a surface crust of particulate organic matter, or an artificial crust can be established. Slurry storages are net sources of atmospheric methane (CH4), but a potential for bacterial oxidation of CH4 in surface crusts was recently suggested in a study......2 during incubation, while intact subsamples were used to characterize CH4 oxidation as a function of CH4 availability and moisture content. Methane oxidation was observed in all materials except for an expanded clay product (Leca) sampled from a pig slurry storage. Despite significant variation...... crusts indicates that there is a potential for stimulating the process by manipulation of gas phase composition above the stored slurry....

  3. Anomalous water dynamics at surfaces and interfaces: synergistic effects of confinement and surface interactions

    Science.gov (United States)

    Biswas, Rajib; Bagchi, Biman

    2018-01-01

    In nature, water is often found in contact with surfaces that are extended on the scale of molecule size but small on a macroscopic scale. Examples include lipid bilayers and reverse micelles as well as biomolecules like proteins, DNA and zeolites, to name a few. While the presence of surfaces and interfaces interrupts the continuous hydrogen bond network of liquid water, confinement on a mesoscopic scale introduces new features. Even when extended on a molecular scale, natural and biological surfaces often have features (like charge, hydrophobicity) that vary on the scale of the molecular diameter of water. As a result, many new and exotic features, which are not seen in the bulk, appear in the dynamics of water close to the surface. These different behaviors bear the signature of both water-surface interactions and of confinement. In other words, the altered properties are the result of the synergistic effects of surface-water interactions and confinement. Ultrafast spectroscopy, theoretical modeling and computer simulations together form powerful synergistic approaches towards an understanding of the properties of confined water in such systems as nanocavities, reverse micelles (RMs), water inside and outside biomolecules like proteins and DNA, and also between two hydrophobic walls. We shall review the experimental results and place them in the context of theory and simulations. For water confined within RMs, we discuss the possible interference effects propagating from opposite surfaces. Similar interference is found to give rise to an effective attractive force between two hydrophobic surfaces immersed and kept fixed at a separation of d, with the force showing an exponential dependence on this distance. For protein and DNA hydration, we shall examine a multitude of timescales that arise from frustration effects due to the inherent heterogeneity of these surfaces. We pay particular attention to the role of orientational correlations and modification of the

  4. Long-time dynamics of laser-cooled ions in the TSR storage ring

    International Nuclear Information System (INIS)

    Mudrich, M.

    2000-01-01

    This diploma thesis studies experimentally the long-time dynamics of laser-cooled 9 Be + -beams at the TSR under different cooling conditions. The goal is to enlarge the understanding of ultra-cold, non-neutral plasma at high center-of-mass energies. By means of improved measurement capabilities one can now for the first time monitor the entire phase-space over a long time. This makes it possible to quantitatively analyse the possibilities and limitations of laser cooling at a storage ring. Under optimum cooling conditions a regime of high phase-space density is reached, close to the region where influences of Coulomb coupling are expected. Furthermore, a Monte-Carlo model is worked out that qualitatively describes the beam dynamics. The model includes the influence of transverse-longitudinal coupling due to intra beam scattering on the longitudinal phase-space distribution. At high phase-space density a sudden disappearance of intra beam collisions is observed experimentally and possible interpretations are given. (orig.)

  5. Lake Storage Measurements For Water Resources Management: Combining Remotely Sensed Water Levels and Surface Areas

    Science.gov (United States)

    Brakenridge, G. R.; Birkett, C. M.

    2013-12-01

    Presently operating satellite-based radar altimeters have the ability to monitor variations in surface water height for large lakes and reservoirs, and future sensors will expand observational capabilities to many smaller water bodies. Such remote sensing provides objective, independent information where in situ data are lacking or access is restricted. A USDA/NASA (http://www.pecad.fas.usda.gov/cropexplorer/global_reservoir/) program is performing operational altimetric monitoring of the largest lakes and reservoirs around the world using data from the NASA/CNES, NRL, and ESA missions. Public lake-level products from the Global Reservoir and Lake Monitor (GRLM) are a combination of archived and near real time information. The USDA/FAS utilizes the products for assessing international irrigation potential and for crop production estimates; other end-users study climate trends, observe anthropogenic effects, and/or are are involved in other water resources management and regional water security issues. At the same time, the Dartmouth Flood Observatory (http://floodobservatory.colorado.edu/), its NASA GSFC partners (http://oas.gsfc.nasa.gov/floodmap/home.html), and associated MODIS data and automated processing algorithms are providing public access to a growing GIS record of the Earth's changing surface water extent, including changes related to floods and droughts. The Observatory's web site also provide both archival and near real time information, and is based mainly on the highest spatial resolution (250 m) MODIS bands. Therefore, it is now possible to provide on an international basis reservoir and lake storage change measurements entirely from remote sensing, on a frequently updating basis. The volume change values are based on standard numerical procedures used for many decades for analysis of coeval lake area and height data. We provide first results of this combination, including prototype displays for public access and data retrieval of water storage

  6. Thermal dynamics of silver clusters grown on rippled silica surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bhatnagar, Mukul, E-mail: mkbh10@gmail.com [FCIPT, Institute for Plasma Research, Gandhinagar, Gujarat (India); Nirma University, Ahmedabad, Gujarat (India); Ranjan, Mukesh [FCIPT, Institute for Plasma Research, Gandhinagar, Gujarat (India); Nirma University, Ahmedabad, Gujarat (India); Jolley, Kenny; Lloyd, Adam; Smith, Roger [Dept. of Mathematical Sciences, Loughborough University, Leicestershire LE11 3TU (United Kingdom); Mukherjee, Subroto [FCIPT, Institute for Plasma Research, Gandhinagar, Gujarat (India); Nirma University, Ahmedabad, Gujarat (India)

    2017-02-15

    Highlights: • Low energy oblique angle ion bombardment forms ripple pattern on silicon surface. • The ripple patterns have wavelengths between 20 and 45 nm and correspondingly low height. • Silver nanoparticles have been deposited at an angle of 70° on patterned silicon templates. • The as-deposited np are annealed in vacuo at temperature of 573 K for a time duration of 1 h. • MD simulation is used to model the process and compare the results to the experiment. • Results show that silver clusters grow preferentially along parallel to the rippled surface. • Mobility of silver atoms depends on the site to which they are bonded on this amorphous surface. • MD simulations show contour ordered coalescence which is dependent on ripple periodicity. - Abstract: Silver nanoparticles have been deposited on silicon rippled patterned templates at an angle of incidence of 70° to the surface normal. The templates are produced by oblique incidence argon ion bombardment and as the fluence increases, the periods and heights of the structures increase. Structures with periods of 20 nm, 35 nm and 45 nm have been produced. Moderate temperature vacuum annealing shows the phenomenon of cluster coalescence following the contour of the more exposed faces of the ripple for the case of 35 nm and 45 nm but not at 20 nm where the silver aggregates into larger randomly distributed clusters. In order to understand this effect, the morphological changes of silver nanoparticles deposited on an asymmetric rippled silica surface are investigated through the use of molecular dynamics simulations for different deposition angles of incidence between 0° and 70° and annealing temperatures between 500 K and 900 K. Near to normal incidence, clusters are observed to migrate over the entire surface but for deposition at 70°, a similar patterning is observed as in the experiment. The random distribution of clusters for the periodicity ≈ of 20 nm is linked to the geometry of the silica

  7. Reaction dynamics of small molecules at metal surfaces

    International Nuclear Information System (INIS)

    Samson, P.A.

    1999-09-01

    The dissociation-desorption dynamics of D 2 upon the Sn/Pt(111) surface alloy are dependent on the surface concentration of Sn. The p(2 x 2) Sn/Pt(111) alloy surface (Θ Sn = 0.25 ML), is initially ∼30 times less reactive towards D 2 adsorption than clean Pt(111). On the (√3 x √3) R30 deg Sn/Pt(111) alloy surface (Θ Sn = 0.33 ML), increased inhibition of D 2 adsorption is reported, with S o ∼ 10 -5 at low energy, coinciding with the loss of stable Pt 3 hollow sites and a significant reduction in the D atom binding energy. Sticking on the √3 alloy is activated with an increased energy threshold of ∼280 meV, with no evidence that vibration enhances dissociation. The barrier to dissociation remains in the entrance channel before the D 2 bond begins to stretch. Vibrational excitation is, however, observed in nitrogen desorption from the catalytic reaction of NO + H 2 over Pd(110). For a surface at 600 K, N 2 vibrational state population ratios of P(v=1/v=0) = 0.50 ± 0.05 and P(v=2/v=0) = 0.60 ± 0.20 are reported. Desorption occurs via the N(ad) + N(ad) recombination channel with little energy released into translation and rotation. The translational energy release observed is dependent on the N 2 vibrational state, with translational temperatures of 425 K, 315 K and 180 K reported for the v=0, 1 and 2 states respectively. Sub-thermal energy releases and normally directed angular distributions suggest the influence of a trapping mechanism, recombining molecules scattering through a molecularly adsorbed state, with a transition state of large d NN responsible for the product vibrational excitation. Although N 2 dissociation on Fe(100) forms a simple overlayer structure, on Fe(110), molecular chemisorption does not occur at or above room temperature and the sticking is extremely small (∼10 -6 to 10 -7 ). Activated nitrogen bombardment can be used to prepare a 'surface nitride' with a structure related to the geometry of bulk Fe 4 N. Scanning tunnelling

  8. Dynamics of gas-surface interactions atomic-level understanding of scattering processes at surfaces

    CERN Document Server

    Díez Muniño, Ricardo

    2013-01-01

    This book gives a representative survey of the state of the art of research on gas-surface interactions. It provides an overview of the current understanding of gas surface dynamics and, in particular, of the reactive and non-reactive processes of atoms and small molecules at surfaces. Leading scientists in the field, both from the theoretical and the experimental sides, write in this book about their most recent advances. Surface science grew as an interdisciplinary research area over the last decades, mostly because of new experimental technologies (ultra-high vacuum, for instance), as well as because of a novel paradigm, the ‘surface science’ approach. The book describes the second transformation which is now taking place pushed by the availability of powerful quantum-mechanical theoretical methods implemented numerically. In the book, experiment and theory progress hand in hand with an unprecedented degree of accuracy and control. The book presents how modern surface science targets the atomic-level u...

  9. Surface conductivity dependent dynamic behaviour of an ultrafine atmospheric pressure plasma jet for microscale surface processing

    Energy Technology Data Exchange (ETDEWEB)

    Abuzairi, Tomy [Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561 (Japan); Department of Electrical Engineering, Faculty of Engineering, Universitas Indonesia, Depok 16424 (Indonesia); Okada, Mitsuru [Department of Engineering, Shizuoka University, Hamamatsu 432-8561 (Japan); Bhattacharjee, Sudeep [Department of Physics, Indian Institute of Technology, Kanpur 208016 (India); Nagatsu, Masaaki, E-mail: nagatsu.masaaki@shizuoka.ac.jp [Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561 (Japan); Department of Engineering, Shizuoka University, Hamamatsu 432-8561 (Japan); Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8561 (Japan)

    2016-12-30

    Highlights: • Spatio-temporal behaviors of capillary APPJs are studied for various substrates. • Plasma irradiation area depended on the substrate conductivity and permittivity. • Surface irradiation area was significantly broadened in polymer-like substrate. • Effect of applying a substrate bias on the APPJ irradiation area was investigated. - Abstract: An experimental study on the dynamic behaviour of microcapillary atmospheric pressure plasma jets (APPJs) with 5 μm tip size for surfaces of different conductivity is reported. Electrical and spatio-temporal characteristics of the APPJs are monitored using high voltage probe, current monitor and high speed intensified charge couple device camera. From these experimental results, we presented a simple model to understand the electrical discharge characteristics of the capillary APPJs with double electrodes, and estimated the velocity of the ionization fronts in the jet and the electron density to be 3.5–4.2 km/s and 2–7 × 10{sup 17} m{sup −3}. By analyzing the dynamics of the microcapillary APPJs for different substrate materials, it was found that the surface irradiation area strongly depended on the substrate conductivity and permittivity, especially in the case of polymer-like substrate, surface irradiation area was significantly broadened probably due to the repelling behaviour of the plasma jets from the accumulated electrical charges on the polymer surface. The effect of applying a substrate bias in the range from −900 V to +900 V on the plasma irradiation onto the substrates was also investigated. From the knowledge of the present results, it is helpful for choosing the substrate materials for microscale surface modification.

  10. Surface conductivity dependent dynamic behaviour of an ultrafine atmospheric pressure plasma jet for microscale surface processing

    International Nuclear Information System (INIS)

    Abuzairi, Tomy; Okada, Mitsuru; Bhattacharjee, Sudeep; Nagatsu, Masaaki

    2016-01-01

    Highlights: • Spatio-temporal behaviors of capillary APPJs are studied for various substrates. • Plasma irradiation area depended on the substrate conductivity and permittivity. • Surface irradiation area was significantly broadened in polymer-like substrate. • Effect of applying a substrate bias on the APPJ irradiation area was investigated. - Abstract: An experimental study on the dynamic behaviour of microcapillary atmospheric pressure plasma jets (APPJs) with 5 μm tip size for surfaces of different conductivity is reported. Electrical and spatio-temporal characteristics of the APPJs are monitored using high voltage probe, current monitor and high speed intensified charge couple device camera. From these experimental results, we presented a simple model to understand the electrical discharge characteristics of the capillary APPJs with double electrodes, and estimated the velocity of the ionization fronts in the jet and the electron density to be 3.5–4.2 km/s and 2–7 × 10"1"7 m"−"3. By analyzing the dynamics of the microcapillary APPJs for different substrate materials, it was found that the surface irradiation area strongly depended on the substrate conductivity and permittivity, especially in the case of polymer-like substrate, surface irradiation area was significantly broadened probably due to the repelling behaviour of the plasma jets from the accumulated electrical charges on the polymer surface. The effect of applying a substrate bias in the range from −900 V to +900 V on the plasma irradiation onto the substrates was also investigated. From the knowledge of the present results, it is helpful for choosing the substrate materials for microscale surface modification.

  11. How internal drainage affects evaporation dynamics from soil surfaces ?

    Science.gov (United States)

    Or, D.; Lehmann, P.; Sommer, M.

    2017-12-01

    Following rainfall, infiltrated water may be redistributed internally to larger depths or lost to the atmosphere by evaporation (and by plant uptake from depths at longer time scales). A large fraction of evaporative losses from terrestrial surfaces occurs during stage1 evaporation during which phase change occurs at the wet surface supplied by capillary flow from the soil. Recent studies have shown existence of a soil-dependent characteristic length below which capillary continuity is disrupted and a drastic shift to slower stage 2 evaporation ensues. Internal drainage hastens this transition and affect evaporative losses. To predict the transition to stage 2 and associated evaporative losses, we developed an analytical solution for evaporation dynamics with concurrent internal drainage. Expectedly, evaporative losses are suppressed when drainage is considered to different degrees depending on soil type and wetness. We observe that high initial water content supports rapid drainage and thus promotes the sheltering of soil water below the evaporation depth. The solution and laboratory experiments confirm nonlinear relationship between initial water content and total evaporative losses. The concept contributes to establishing bounds on regional surface evaporation considering rainfall characteristics and soil types.

  12. Immobilizing live Escherichia coli for AFM studies of surface dynamics

    International Nuclear Information System (INIS)

    Lonergan, N.E.; Britt, L.D.; Sullivan, C.J.

    2014-01-01

    Atomic force microscopy (AFM) is a probe-based technique that permits high resolution imaging of live bacterial cells. However, stably immobilizing cells to withstand the probe-based lateral forces remains an obstacle in AFM mediated studies, especially those of live, rod shaped bacteria in nutrient media. Consequently, AFM has been under-utilized in the research of bacterial surface dynamics. The aim of the current study was to immobilize a less adherent Escherichia coli strain in a method that both facilitates AFM imaging in nutrient broth and preserves overall cell viability. Immobilization reagents and buffers were systematically evaluated and the cell membrane integrity was monitored in all sample preparations. As expected, the biocompatible gelatin coated surfaces facilitated stable cell attachment in lower ionic strength buffers, yet poorly immobilized cells in higher ionic strength buffers. In comparison, poly-L-lysine surfaces bound cells in both low and high ionic strength buffers. The benefit of the poly-L-lysine binding capacity was offset by the compromised membrane integrity exhibited by cells on poly-L-lysine surfaces. However, the addition of divalent cations and glucose to the immobilization buffer was found to mitigate this unfavorable effect. Ultimately, immobilization of E. coli cells on poly-L-lysine surfaces in a lower ionic strength buffer supplemented with Mg 2+ and Ca 2+ was determined to provide optimal cell attachment without compromising the overall cell viability. Cells immobilized in this method were stably imaged in media through multiple division cycles. Furthermore, permeability assays indicated that E. coli cells recover from the hypoosmotic stress caused by immobilization in low ionic strength buffers. Taken together, this data suggests that stable immobilization of viable cells on poly-L-lysine surfaces can be accomplished in lower ionic strength buffers that are supplemented with divalent cations for membrane stabilization while

  13. Molecular dynamics simulation of potentiometric sensor response: the effect of biomolecules, surface morphology and surface charge.

    Science.gov (United States)

    Lowe, B M; Skylaris, C-K; Green, N G; Shibuta, Y; Sakata, T

    2018-05-10

    The silica-water interface is critical to many modern technologies in chemical engineering and biosensing. One technology used commonly in biosensors, the potentiometric sensor, operates by measuring the changes in electric potential due to changes in the interfacial electric field. Predictive modelling of this response caused by surface binding of biomolecules remains highly challenging. In this work, through the most extensive molecular dynamics simulation of the silica-water interfacial potential and electric field to date, we report a novel prediction and explanation of the effects of nano-morphology on sensor response. Amorphous silica demonstrated a larger potentiometric response than an equivalent crystalline silica model due to increased sodium adsorption, in agreement with experiments showing improved sensor response with nano-texturing. We provide proof-of-concept that molecular dynamics can be used as a complementary tool for potentiometric biosensor response prediction. Effects that are conventionally neglected, such as surface morphology, water polarisation, biomolecule dynamics and finite-size effects, are explicitly modelled.

  14. Exploring the potential of the cosmic-ray neutron method to measure interception storage dynamics

    Science.gov (United States)

    Jakobi, Jannis; Bogena, Heye; Huisman, Johan Alexander; Diekkrüger, Bernd; Vereecken, Harry

    2017-04-01

    Cosmic-ray neutron soil moisture probes are an emerging technology that relies on the negative correlation between near-surface fast neutron counts and soil moisture content. Hydrogen atoms in the soil, which are mainly present as water, moderate the secondary neutrons on the way back to the surface. Any application of this method needs to consider the sensitivity of the neutron counts to additional sources of hydrogen (e.g. above- and below-ground biomass, humidity of the lower atmosphere, lattice water of the soil minerals, organic matter and water in the litter layer, intercepted water in the canopy, and soil organic matter). In this study, we analyzed the effects of canopy-intercepted water on the cosmic-ray neutron counts. For this, an arable field cropped with sugar beet was instrumented with several cosmic-ray neutron probes and a wireless sensor network with more than 140 in-situ soil moisture sensors. Additionally rainfall interception was estimated using a new approach coupling throughfall measurements and leaf wetness sensors. The derived interception storage was used to correct for interception effects on cosmic ray neutrons to enhance soil water content prediction. Furthermore, the potential for a simultaneous prediction of above- and below-ground biomass, soil moisture and interception was tested.

  15. Influence of alginate impression materials and storage time on surface detail reproduction and dimensional accuracy of stone models.

    Science.gov (United States)

    Guiraldo, Ricardo D; Moreti, Ana F F; Martinelli, Julia; Berger, Sandrine B; Meneghel, Luciana L; Caixeta, Rodrigo V; Sinhoreti, Mário A C

    2015-01-01

    This study compared the surface detail reproduction and dimensional accuracy of stone models obtained from molds prepared using different alginate impression materials (Cavex ColorChange, Hydrogum 5, or Jeltrate Plus) and with different storage times (1, 3, and 5 days) to models from molds that were filled immediately with no storage time. The molds were prepared over a matrix containing 50-μm line, (ISO 1563 standard) under pressure with a perforated metal tray. The molds were removed 2 minutes after loss of sticky consistency and either filled immediately or stored in closed jars at 100% relative humidity and 37°C for 1, 3, or 5 days. The molds were filled with dental plaster (Durone IV). Surface detail reproduction and dimensional accuracy were evaluated using optical microscopy on the 50-μm wide line, which was 25 mm in length, according to ISO 1563 standard. The dimensional accuracy results (%) were subjected to analysis of variance. The 50-μm wide line (ISO 1563 standard) was completely reproduced by all alginate impression materials regardless of the storage time. There was no statistically significant difference in the mean dimensional accuracy values of stone models made from molds composed of different alginate impression materials and with different storage times (p = 0.989). In conclusion, storing the mold for five days prior to filling did not change the surface detail reproduction or dimensional accuracy of the alginates examined in this study.

  16. Dynamic Analysis of a Hybrid Energy Storage System (H-ESS Coupled to a Photovoltaic (PV Plant

    Directory of Open Access Journals (Sweden)

    Linda Barelli

    2018-02-01

    Full Text Available Nowadays energy storage is strongly needed to allow grid safety and stability due to the wide penetration of renewable plants. Mainly economic and technological issues impede a relevant integration of conventional storage devices in the energy system. In this scenario, the hybridization of different storage technologies can be a techno-economic solution useful to overcome these issues and promote their diffusion. Hybridization allows multi-operation modes of the Energy Storage System (ESS, merging the positive features of base-technologies and extending their application ranges. This paper provides a dynamic analysis of a hybrid energy storage system (H-ESS consisting of a flywheel and a battery pack coupled to a photovoltaic generation plant and a residential load up to 20 kW. A dynamic model of the overall micro-grid (MG was developed implementing the H-ESS preliminary sizing and a suitable management algorithm. The instantaneous behavior of each component was evaluated. A brief summary of the MG performance at different weather and load conditions was provided together with a characterization of the impact of power fluctuations on the battery current and on the power exchange with the grid.

  17. Examination of the rheological properties of stirred joghurt during the long-term storage by using dynamic oscillation method

    Directory of Open Access Journals (Sweden)

    Milica Vilušić

    2003-07-01

    Full Text Available In this work the rheological properties of stirred yoghurt during the longterm storage at 4 and 8°C were investigated. The optimal quantity of additives, in order to increase dry matter content (whole milk powder and whey protein-lactalbumin, was preliminary determined and the fermentation was performed. During 42 days, i.e., 1st, 7th, 14th, 21st, 28th, 35th and 42nd day of storage of stirred yoghurt, in refrigerator at 4 and 8°C, the changes of pH value, acidity and rheological properties by using of dynamic oscillation method were observed. Results of this work indicated that an addition of whole milk powder and whey protein have an influence on rheological properties of stirred yoghurt. The long-term storage of stirred yoghurt and the results of dynamic oscilations showed permanently higher G’storage (elasticity modulus, where elastic properties of viscoelastic products dominate, in comparison with the G” loss (viscosity modulus. Increased moduls of elasticy and viscosity, as function of time, permanently occurs at pH value 4.00 and lower, as an indication of alteration of long casein chains in the coagulum structure. Different temperatures of storage had no influence on changes of rheological properties of examinated types of stirred yoghur. The relation of above mentioned moduls of elasticy and viscosity kept the same increasing tendency.

  18. Changes in surface characteristics of two different resin composites after 1 year water storage: An SEM and AFM study.

    Science.gov (United States)

    Tekçe, Neslihan; Pala, Kansad; Demirci, Mustafa; Tuncer, Safa

    2016-11-01

    To evaluate changes in surface characteristics of two different resin composites after 1 year of water storage using a profilometer, Vickers hardness, scanning electron microscopy (SEM), and atomic force microscopy (AFM). A total of 46 composite disk specimens (10 mm in diameter and 2 mm thick) were fabricated using Clearfil Majesty Esthetic and Clearfil Majesty Posterior (Kuraray Medical Co, Tokyo, Japan). Ten specimens from each composite were used for surface roughness and microhardness tests (n = 10). For each composite, scanning electron microscope (SEM, n = 2) and atomic force microscope (AFM, n = 1) images were obtained after 24 h and 1 year of water storage. The data were analyzed using two-way analysis of variance and a post-hoc Bonferroni test. Microhardness values of Clearfil Majesty Esthetic decreased significantly (78.15-63.74, p = 0.015) and surface roughness values did not change after 1 year of water storage (0.36-0.39, p = 0.464). Clearfil Majesty Posterior microhardness values were quite stable (138.74-137.25, p = 0.784), and surface roughness values increased significantly (0.39-0.48, p = 0.028) over 1 year. One year of water storage caused microhardness values for Clearfil Majesty Esthetic to decrease and the surface roughness of Clearfil Majesty Posterior increased. AFM and SEM images demonstrated surface detoration of the materials after 1 year and ensured similar results with the quantitative test methods. SCANNING 38:694-700, 2016. © 2016 Wiley Periodicals, Inc. © Wiley Periodicals, Inc.

  19. A study on EUV reticle surface molecular contamination under different storage conditions in a HVM foundry fab

    Science.gov (United States)

    Singh, SherJang; Yatzor, Brett; Taylor, Ron; Wood, Obert; Mangat, Pawitter

    2017-03-01

    The prospect of EUVL (Extreme Ultraviolet Lithography) insertion into HVM (High Volume Manufacturing) has never been this promising. As technology is prepared for "lab to fab" transition, it becomes important to comprehend challenges associated with integrating EUVL infrastructure within existing high volume chip fabrication processes in a foundry fab. The existing 193nm optical lithography process flow for reticle handling and storage in a fab atmosphere is well established and in-fab reticle contamination concerns are mitigated with the reticle pellicle. However EUVL reticle pellicle is still under development and if available, may only provide protection against particles but not molecular contamination. HVM fab atmosphere is known to be contaminated with trace amounts of AMC's (Atmospheric Molecular Contamination). If such contaminants are organic in nature and get absorbed on the reticle surface, EUV photon cause photo-dissociation resulting into carbon generation which is known to reduce multilayer reflectivity and also degrades exposure uniformity. Chemical diffusion and aggregation of other ions is also reported under the e-beam exposure of a EUV reticle which is known to cause haze issues in optical lithography. Therefore it becomes paramount to mitigate absorbed molecular contaminant concerns on EUVL reticle surface. In this paper, we have studied types of molecular contaminants that are absorbed on an EUVL reticle surface under HVM fab storage and handling conditions. Effect of storage conditions (gas purged vs atmospheric) in different storage pods (Dual pods, Reticle Clamshells) is evaluated. Absorption analysis is done both on ruthenium capping layer as well as TaBN absorber. Ru surface chemistry change as a result of storage is also studied. The efficacy of different reticle cleaning processes to remove absorbed contaminant is evaluated as well.

  20. Adaptive Dynamic Surface Control for Generator Excitation Control System

    Directory of Open Access Journals (Sweden)

    Zhang Xiu-yu

    2014-01-01

    Full Text Available For the generator excitation control system which is equipped with static var compensator (SVC and unknown parameters, a novel adaptive dynamic surface control scheme is proposed based on neural network and tracking error transformed function with the following features: (1 the transformation of the excitation generator model to the linear systems is omitted; (2 the prespecified performance of the tracking error can be guaranteed by combining with the tracking error transformed function; (3 the computational burden is greatly reduced by estimating the norm of the weighted vector of neural network instead of the weighted vector itself; therefore, it is more suitable for the real time control; and (4 the explosion of complicity problem inherent in the backstepping control can be eliminated. It is proved that the new scheme can make the system semiglobally uniformly ultimately bounded. Simulation results show the effectiveness of this control scheme.

  1. Dynamic characterisation of the specific surface area for fracture networks

    Science.gov (United States)

    Cvetkovic, V.

    2017-12-01

    One important application of chemical transport is geological disposal of high-level nuclear waste for which crystalline rock is a prime candidate for instance in Scandinavia. Interconnected heterogeneous fractures of sparsely fractured rock such as granite, act as conduits for transport of dissolved tracers. Fluid flow is known to be highly channelized in such rocks. Channels imply narrow flow paths, adjacent to essentially stagnant water in the fracture and/or the rock matrix. Tracers are transported along channelised flow paths and retained by minerals and/or stagnant water, depending on their sorption properties; this mechanism is critical for rocks to act as a barrier and ultimately provide safety for a geological repository. The sorbing tracers are retained by diffusion and sorption on mineral surfaces, whereas non-sorbing tracers can be retained only by diffusion into stagnant water of fractures. The retention and transport properties of a sparsely fractured rock will primarily depend on the specific surface area (SSA) of the fracture network which is determined by the heterogeneous structure and flow. The main challenge when characterising SSA on the field-scale is its dependence on the flow dynamics. We first define SSA as a physical quantity and clarify its importance for chemical transport. A methodology for dynamic characterisation of SSA in fracture networks is proposed that relies on three sets of data: i) Flow rate data as obtained by a flow logging procedure; ii) transmissivity data as obtained by pumping tests; iii) fracture network data as obtained from outcrop and geophysical observations. The proposed methodology utilises these data directly as well as indirectly through flow and particle tracking simulations in three-dimensional discrete fracture networks. The methodology is exemplified using specific data from the Swedish site Laxemar. The potential impact of uncertainties is of particular significance and is illustrated for radionuclide

  2. Influence of heat treatment and veneering on the storage modulus and surface of zirconia ceramic

    NARCIS (Netherlands)

    Siavikis, G.; Behr, M.; van der Zel, J.M.; Feilzer, A.J.; Rosentritt, M.

    2011-01-01

    Objectives: Glass-ceramic veneered zirconia is used for the application as fixed partial dentures. The aim of this investigation was to evaluate whether the heat treatment during veneering, the application of glass-ceramic for veneering or long term storage has an influence on the storage modulus of

  3. He atom surface scattering: Surface dynamics of insulators, overlayers and crystal growth

    International Nuclear Information System (INIS)

    1992-01-01

    Investigations have focused primarily on surface structure and dynamics of ionic insulators, epitaxial growth onto alkali halide crystals and multiphoton studies. The surface dynamics of RbCl has been re-examined. We have developed a simple force constant model which provides insight into the dynamics of KBr overlayers on NaCl(001), a system with a large lattice mismatch. The KBr/NaCl(001) results are compared to Na/Cu(001) and NaCl/Ge(001). We have completed epitaxial growth experiments for KBr onto RbCl(001). Slab dynamics calculations using a shell model for this system with very small lattice mismatch are being carried out in collaboration with Professor Manson of Clemson University and with Professor Schroeder in Regensburg, Germany. Extensive experiments on multiphoton scattering of helium atoms onto NaCl and, particularly, LiF have been carried out and the theory has been developed to a rather advanced stage by Professor Manson. This work will permit the extraction of more information from time-of-flight spectra. It is shown that the theoretical model provides a very good description of the multiphoton scattering from organic films. Work has started on self-assembling organic films on gold (alkyl thiols/Au(111)). We have begun to prepare and characterize the gold crystal; one of the group members has spent two weeks at the Oak Ridge National Laboratory learning the proper Au(111) preparation techniques. One of our students has carried out neutron scattering experiments on NiO, measuring both bulk phonon and magnon dispersion curves

  4. Dynamic water allocation policies improve the global efficiency of storage systems

    Science.gov (United States)

    Niayifar, Amin; Perona, Paolo

    2017-06-01

    Water impoundment by dams strongly affects the river natural flow regime, its attributes and the related ecosystem biodiversity. Fostering the sustainability of water uses e.g., hydropower systems thus implies searching for innovative operational policies able to generate Dynamic Environmental Flows (DEF) that mimic natural flow variability. The objective of this study is to propose a Direct Policy Search (DPS) framework based on defining dynamic flow release rules to improve the global efficiency of storage systems. The water allocation policies proposed for dammed systems are an extension of previously developed flow redistribution rules for small hydropower plants by Razurel et al. (2016).The mathematical form of the Fermi-Dirac statistical distribution applied to lake equations for the stored water in the dam is used to formulate non-proportional redistribution rules that partition the flow for energy production and environmental use. While energy production is computed from technical data, riverine ecological benefits associated with DEF are computed by integrating the Weighted Usable Area (WUA) for fishes with Richter's hydrological indicators. Then, multiobjective evolutionary algorithms (MOEAs) are applied to build ecological versus economic efficiency plot and locate its (Pareto) frontier. This study benchmarks two MOEAs (NSGA II and Borg MOEA) and compares their efficiency in terms of the quality of Pareto's frontier and computational cost. A detailed analysis of dam characteristics is performed to examine their impact on the global system efficiency and choice of the best redistribution rule. Finally, it is found that non-proportional flow releases can statistically improve the global efficiency, specifically the ecological one, of the hydropower system when compared to constant minimal flows.

  5. Configurational and constitutional information storage: multiple dynamics in systems based on pyridyl and acyl hydrazones.

    Science.gov (United States)

    Chaur, Manuel N; Collado, Daniel; Lehn, Jean-Marie

    2011-01-03

    The C=N group of hydrazones can undergo E/Z isomerization both photochemically and thermally, allowing the generation of a closed process that can be tuned by either of these two physical stimuli. On the other hand, hydrazine-exchange reactions enable a constitutional change in a given hydrazone. The two classes of processes: 1) configurational (physically stimulated) and 2) constitutional (chemically stimulated) give access to short-term and long-term information storage, respectively. Such transformations are reported herein for two hydrazones (bis-pyridyl hydrazone and 2-pyridinecarboxaldehyde phenylhydrazone) that undergo a closed, chemically or physically driven process, and, in addition, can be locked or unlocked at will by metal-ion coordination or removal. These features also extend to acyl hydrazones derived from 2-pyridinecarboxaldehyde. Similarly to the terpydine-like hydrazones, such acyl hydrazones can undergo both constitutional and configurational changes, as well as metal-ion coordination. All these types of hydrazones represent dynamic systems capable of acting as multiple state molecular devices, in which the presence of coordination sites furthermore allows the metal ion-controlled locking and unlocking of the interconversion of the different states. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Dynamic Modelling of a Solar Water Pumping System with Energy Storage

    Directory of Open Access Journals (Sweden)

    Shatadru Biswas

    2018-01-01

    Full Text Available This paper describes the dynamic modelling of a system used for extraction of groundwater for irrigation using an alternative source of energy. The system is designed based on data of an existing project in Lalmonirhat, Bangladesh. The system comprises a 38.4 kWp solar photovoltaic array, inverter, AC motor, and pump set, which can discharge a maximum of 1,930 m3 of water per day. MATLAB simulation is performed with two types of energy storage system: (i electric energy using a battery bank and (ii stored water in a large water tank. A large battery bank and a transformer are needed in the former one, which turns out as a costly solution. The latter one requires a boost converter and a large water tank to store around 2,000 m3 of water, which is also a costly solution. A combination of both systems yields an efficient and economical solution. The effectiveness of these three systems is compared with conventional diesel engine system.

  7. The effect of oxygen storage capacity on the dynamic characteristics of an automotive catalytic converter

    Energy Technology Data Exchange (ETDEWEB)

    Shamim, T. [Michigan-Dearborn Univ., Dearborn, MI (United states). Dept. of Mechanical Engineering

    2007-07-01

    Automotive catalytic converters that reduce engine exhaust emissions are subject to transient conditions during a typical driving cycle. These conditions arise from changes in driving mode, the hysteresis and flow lags of the feedback control system, and result in fluctuations of air-fuel, exhaust gas flow rates and temperatures. The catalyst performance is also highly influenced by the oxygen storage capacity (OSC). This paper examined the influence of OSC on the catalyst dynamic behavior. The transient conditions were simulated by considering the catalyst subjected to temporal modulation in air-fuel ratio, exhaust gas composition and temperature. The paper presented the mathematical formulation including the development of governing equations. The governing equations were developed by considering the conservation of mass, energy and chemical species. It also presented the results and discussed the effect of sinusoidal modulation in the air-fuel ratio as well as the effect of sinusoidal modulation in exhaust composition. It was concluded that the presence of the OSC sensitivity influenced its response to the imposed modulation. The specific effect was dependent on the operating conditions and the type of the imposed modulations. 10 refs., 1 tab., 3 figs.

  8. Analytic calculation of the dynamical aperture for the two dimensional betatron motion in storage rings

    International Nuclear Information System (INIS)

    Hagel, J.; Moshammer, H.

    1988-01-01

    In this paper the authors study the on- momentum nonlinear equations of motion for the coupled transverse motion of a single charged particle in a storage ring. The authors seek for the maximum initial linear amplitudes in the two transverse directions x and y which lead to bounded particle motion as t tends to infinity. Although the authors restrict themselves to sextupole fields in this paper, the authors may easily extend the method to any order multipole. The aim of this work is to derive an analytic approximate expression for the dynamical aperture. The authors approach the solutions of x and y by use of a classical secular perturbation theory. Every coefficient of the perturbation series can be expressed as an analytic function of all the lower order coefficients. Although perturbation theory if it is evaluated to certain specific order leads only to an approximation in terms of bounded (trigonometric) functions the authors may derive information about the stability limit by considering the convergency radius of the general perturbation. This is done in the present paper by deriving an approximate analytic expression for the n-th order perturbation contribution of the whole series using only results up to second order. The actual calculations have been performed for the fully two dimensional case but for simplicity the authors shall explain only the one dimensional case of the pure horizontal motion

  9. Molecular Dynamics Studies of Overbased Detergents on a Water Surface.

    Science.gov (United States)

    Bodnarchuk, M S; Dini, D; Heyes, D M; Breakspear, A; Chahine, S

    2017-07-25

    Molecular dynamics (MD) simulations are reported of model overbased detergent nanoparticles on a model water surface which mimic their behavior on a Langmuir trough or large water droplet in engine oil. The simulations predict that the structure of the nanoparticle on a water surface is different to when it is immersed in a bulk hydrophobic solvent. The surfactant tails are partly directed out of the water, while the carbonate core maximizes its extent of contact with the water. Umbrella sampling calculations of the potential of mean force between two particles showed that they are associated with varying degrees with a maximum binding free energy of ca. 10 k B T for the salicylate stabilized particle, ca. 8 k B T for a sulfurized alkyl phenate stabilized particle, and ca. 5 k B T for a sulfonate stabilized particle. The differences in the strength of attraction depend on the proximity of nearest approach and the energy penalty associated with the disruption of the hydration shell of water molecules around the calcium carbonate core when the two particles approach. This is greatest for the sulfonate particle, which partially loses the surfactant ions to the solution, and least for the salicylate, which forms the weakest water "cage". The particles are separated by a water hydration layer, even at the point of closest approach.

  10. Time course of surface characteristics of alkali- and heat-treated titanium dental implants during vacuum storage.

    Science.gov (United States)

    Kamo, Michimasa; Kyomoto, Masayuki; Miyaji, Fumiaki

    2017-08-01

    Current efforts to shorten the healing times of life-long dental implants and prevent their fouling by organic impurities have focused on using surface-modification treatments and alternative packaging, respectively. In this study, we investigated the time course of the surface characteristics, including the wettability, a protein-adsorption and apatite-formation abilities, of alkali- and heat-treated (AH-treated) Ti samples during storage in vacuum over a period of 52 weeks. The AH treatment resulted in the formation of a nanometer-scale needle-like rougher surface of the Ti samples. Although the water contact angle of the AH-treated Ti sample increased slightly, it remained as low as approximately 10° even after storage in vacuum for 52 weeks. There was no significant difference in the protein-adsorption and apatite-formation abilities of the AH-treated Ti sample before and after storage. Further, the AH-treated Ti sample exhibited greater protein-adsorption and apatite-formation abilities compared with the untreated one; regardless of the samples stored in vacuum or not. Apatite formed only on the AH-treated Ti surface. Therefore, subjecting Ti dental implants to the AH treatment and storing them in vacuum should help prevent their surfaces from getting contaminated. Further, it is expected that AH-treated Ti dental implants controllably aged during a shelf storage will exhibit high stability and bone-bonding bioactivity. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1453-1460, 2017. © 2016 Wiley Periodicals, Inc.

  11. Dynamic Prediction of Power Storage and Delivery by Data-Based Fractional Differential Models of a Lithium Iron Phosphate Battery

    Directory of Open Access Journals (Sweden)

    Yunfeng Jiang

    2016-07-01

    Full Text Available A fractional derivative system identification approach for modeling battery dynamics is presented in this paper, where fractional derivatives are applied to approximate non-linear dynamic behavior of a battery system. The least squares-based state-variable filter (LSSVF method commonly used in the identification of continuous-time models is extended to allow the estimation of fractional derivative coefficents and parameters of the battery models by monitoring a charge/discharge demand signal and a power storage/delivery signal. In particular, the model is combined by individual fractional differential models (FDMs, where the parameters can be estimated by a least-squares algorithm. Based on experimental data, it is illustrated how the fractional derivative model can be utilized to predict the dynamics of the energy storage and delivery of a lithium iron phosphate battery (LiFePO 4 in real-time. The results indicate that a FDM can accurately capture the dynamics of the energy storage and delivery of the battery over a large operating range of the battery. It is also shown that the fractional derivative model exhibits improvements on prediction performance compared to standard integer derivative model, which in beneficial for a battery management system.

  12. He atom-surface scattering: Surface dynamics of insulators, overlayers and crystal growth

    International Nuclear Information System (INIS)

    1992-01-01

    Investigations in this laboratory have focused on the surface structure and dynamics of ionic insulators and on epitaxial growth onto alkali halide crystals. In the later the homoepitaxial growth of NaCl/NaCl(001) and the heteroepitaxial growth of KBr/NaCl(001), NaCl/KBr(001) and KBr/RbCl(001) have been studied by monitoring the specular He scattering as a function of the coverage and by measuring the angular and energy distributions of the scattered He atoms. These data provide information on the surface structure, defect densities, island sizes and surface strain during the layer-by-layer growth. The temperature dependence of these measurements also provides information on the mobilities of the admolecules. He atom scattering is unique among surface probes because the low-energy, inert atoms are sensitive only to the electronic structure of the topmost surface layer and are equally applicable to all crystalline materials. It is proposed for the next year to exploit further the variety of combinations possible with the alkali halides in order to carry out a definitive study of epitaxial growth in the ionic insulators. The work completed so far, including measurements of the Bragg diffraction and surface dispersion at various stages of growth, appears to be exceptionally rich in detail, which is particularly promising for theoretical modeling. In addition, because epitaxial growth conditions over a wide range of lattice mismatches is possible with these materials, size effects in growth processes can be explored in great depth. Further, as some of the alkali halides have the CsCl structure instead of the NaCl structure, we can investigate the effects of the heteroepitaxy with materials having different lattice preferences. Finally, by using co-deposition of different alkali halides, one can investigate the formation and stability of alloys and even alkali halide superlattices

  13. Applications of granular-dynamics numerical simulations to asteroid surfaces

    Science.gov (United States)

    Richardson, D. C.; Michel, P.; Schwartz, S. R.; Yu, Y.; Ballouz, R.-L.; Matsumura, S.

    2014-07-01

    Spacecraft images and indirect observations including thermal inertia measurements indicate most small bodies have surface regolith. Evidence of granular flow is also apparent in the images. This material motion occurs in very low gravity, therefore in a totally different gravitational environment than on the Earth. Upcoming sample-return missions to small bodies, and possible future manned missions, will involve interaction with the surface regolith, so it is important to develop tools to predict the surface response. We have added new capabilities to the N-body gravity tree code pkdgrav [1,2] that permit the simulation of granular dynamics, including multi-contact physics and friction forces, using the soft-sphere discrete-element method [3]. The numerical approach has been validated through comparison with laboratory experiments (e.g., [3,4]). (1) We carried out impacts into granular materials using different projectile shapes under Earth's gravity [5] and compared the results to laboratory experiments [6] in support of JAXA's Hayabusa 2 asteroid sample-return mission. We tested different projectile shapes and confirmed that the 90-degree cone was the most efficient at excavating mass when impacting 5-mm-diameter glass beads. Results are sensitive to the normal coefficient of restitution and the coefficient of static friction. Preliminary experiments in micro-gravity for similar impact conditions show both the amount of ejected mass and the timescale of the impact process increase, as expected. (2) It has been found (e.g., [7,8]) that ''fresh'' (unreddened) Q-class asteroids have a high probability of recent planetary encounters (˜1 Myr; also see [9]), suggesting that surface refreshening may have occurred due to tidal effects. As an application of the potential effect of tidal interactions, we carried out simulations of Apophis' predicted 2029 encounter with the Earth to see whether regolith motion might occur, using a range of plausible material parameters

  14. Climbing Robot for Ferromagnetic Surfaces with Dynamic Adjustment of the Adhesion System

    Directory of Open Access Journals (Sweden)

    Manuel F. Silva

    2012-01-01

    Full Text Available This paper presents a climbing robot with wheeled locomotion and adhesion through permanent magnets, developed with the intention of being used in the inspection of different types of man-made ferromagnetic structures, such as towers for wind turbines, fuel storage tanks, and ship hulls. In this paper are presented the main considerations thought for its project, as well as several constructive aspects, among which are detailed its mechanical and electrical construction, the implemented control architecture, and the human-machine interface developed for the manual and automatic control of the vehicle while in operation. Although it can be manually controlled, the vehicle is designed to have a semiautonomous behavior, allowing a remote inspection process controlled by a technician, this way reducing the risks associated with the human inspection of tall structures and ATEX places. The distinguishing characteristic of this robot is its dynamic adjustment system of the permanent magnets in order to assure the machine adhesion to the surfaces, even when crossing slightly irregular and curved surfaces with a large radius.

  15. Impact of thermal energy storage properties on solar dynamic space power conversion system mass

    Science.gov (United States)

    Juhasz, Albert J.; Coles-Hamilton, Carolyn E.; Lacy, Dovie E.

    1987-01-01

    A 16 parameter solar concentrator/heat receiver mass model is used in conjunction with Stirling and Brayton Power Conversion System (PCS) performance and mass computer codes to determine the effect of thermal energy storage (TES) material property changes on overall PCS mass as a function of steady state electrical power output. Included in the PCS mass model are component masses as a function of thermal power for: concentrator, heat receiver, heat exchangers (source unless integral with heat receiver, heat sink, regenerator), heat engine units with optional parallel redundancy, power conditioning and control (PC and C), PC and C radiator, main radiator, and structure. Critical TES properties are: melting temperature, heat of fusion, density of the liquid phase, and the ratio of solid-to-liquid density. Preliminary results indicate that even though overall system efficiency increases with TES melting temperature up to 1400 K for concentrator surface accuracies of 1 mrad or better, reductions in the overall system mass beyond that achievable with lithium fluoride (LiF) can be accomplished only if the heat of fusion is at least 800 kJ/kg and the liquid density is comparable to that of LiF (1800 kg/cu m).

  16. Real-Time Dynamic Simulation of Korean Power Grid for Frequency Regulation Control by MW Battery Energy Storage System

    Directory of Open Access Journals (Sweden)

    Tae-Hwan Jin

    2016-12-01

    Full Text Available The aim of this study was to develop a real-time dynamic simulator of a power grid with power plant and battery model. The simulator was used to investigate the frequency control characteristics of a megawatt-scale high-capacity energy storage system connected to the electric power grid. In this study, a lithium-ion secondary battery was chosen as one of the batteries for a grid-connected model. The dynamics of the model was analysed in both steady and transient states. The frequency control system of the battery model plays a role in regulating the grid frequency by controlling the power of energy storage systems according to process variables and grid frequencies. The power grid model based on the current power network of South Korea, included power plants, substations and power demands. The power supply is classified by the type of turbine generator as thermal, nuclear, hydro power, pumped power storage, combined power plants, and batteries, including high-capacity energy storage systems rated for a maximum of 500 MW. This study deals with an installed capacity of 87.17 GW and peak load of 77.30 GW in the Korean power grid. For 24 hours of operation, the maximum and minimum power outputs were simulated as 61.59 GW and 46.32 GW, respectively. The commercialized real-time dynamic simulation software ProTRAX was used. The simulation was conducted to observe the operation characteristics of the frequency control system during a breakdown of power plants, as well as under governor-free operation, auto generation control operation, and with the battery energy storage system connected. The results show that the model is valid for each power plant breakdown simulation. They also confirm that the output power and frequency controls of the battery operated well during simulations.

  17. Surface Passivation of Lithium-Ion Electrodes: A Path to High-Performance Energy Storage

    Data.gov (United States)

    National Aeronautics and Space Administration — Energy storage is one of the most crucial aspects of space technology. Whether the energy is stored as fuel in the solid rocket boosters or as electrochemical energy...

  18. The deterioration during transport and storage of tomato fruits by microorganisms contaminating the surface and latent infected tissue

    OpenAIRE

    河野, 又四; 寺下, 隆夫

    1988-01-01

    [Author abstract]Deterioration during transport and storage of tomato fruits is generally thought to be caused by microorganisms contaminating the surface and latent infected tissue of apparently healthy fruit. Counts of viable airborne microorganisms showed that there were more in plastic greenhouses than in open culure of tomatoes. Altemaria, Aspergillus niger, Asp. oryzae, Cladosporium, Fusarium, Mucor, Penicillium, Trichoderma, Trichothecium, Bacillus, Erwinia and Pseudomonas were among t...

  19. Static and Dynamic Stability Analysis of Distributed Energy Resources Components with Storage Devices and Loads for Smart Grids

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Groza, V.

    2011-01-01

    of the Smart Grids (SGs). A SG can operate interconnected to the main distribution grid or in islanded mode. This paper presents experimental tests for static and dynamic stability analysis carried out in a dedicated laboratory for research in distributed control and smart grid with a high share of renewable......The distributed energy resources (DER) contains several technologies, such as diesel engines, small wind turbines, photovoltaic inverters, etc. The control of DER components with storage devices and (controllable) loads, such as batteries, capacitors, dump loads, are central to the concept...... energy production. Moreover to point out, on a laboratory scale, the coupling between DR and storage and to effectively compensate wind fluctuations a number of tests have been done. In order to find out the parameters of various types of DER components for dynamic simulation models a number of tests...

  20. The estimation of dynamic contact angle of ultra-hydrophobic surfaces using inclined surface and impinging droplet methods

    Science.gov (United States)

    Jasikova, Darina; Kotek, Michal

    2014-03-01

    The development of industrial technology also brings with optimized surface quality, particularly where there is contact with food. Application ultra-hydrophobic surface significantly reduces the growth of bacteria and facilitates cleaning processes. Testing and evaluation of surface quality are used two methods: impinging droplet and inclined surface method optimized with high speed shadowgraphy, which give information about dynamic contact angle. This article presents the results of research into new methods of measuring ultra-hydrophobic patented technology.

  1. He-atom surface scattering apparatus for studies of crystalline surface dynamics. Progress report, May 1, 1985-April 30, 1986

    International Nuclear Information System (INIS)

    1986-01-01

    The primary goal of this grant is the construction of a state-of-the-art He atom-crystal surface scattering apparatus which will be capable of measuring both elastic and inelastic scattering of He atoms from crystal surfaces of metals, semiconductors and insulators. First, the apparatus will be constructed and characterized, after which a program of studies on the surface dynamics of a variety of crystal surfaces will be started. 6 refs., 2 figs

  2. Surface Freshwater Storage and Variability in the Amazon Basin from Multi-Satellite Observations, 1993-2007

    Science.gov (United States)

    Papa, Fabrice; Frappart, Frederic; Guntner, Andreas; Prigent, Catherine; Aires, Filipe; Getirana, Augusto; Maurer, Raffael

    2013-01-01

    The amount of water stored and moving through the surface water bodies of large river basins (river, floodplains, wetlands) plays a major role in the global water and biochemical cycles and is a critical parameter for water resources management. However, the spatio-temporal variations of these freshwater reservoirs are still widely unknown at the global scale. Here, we propose a hypsographic curve approach to estimate surface freshwater storage variations over the Amazon basin combining surface water extent from a multi-satellite-technique with topographic data from the Global Digital Elevation Model (GDEM) from Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Monthly surface water storage variations for 1993-2007 are presented, showing a strong seasonal and interannual variability, and are evaluated against in situ river discharge and precipitation. The basin-scale mean annual amplitude of approx. 1200 cu km is in the range of previous estimates and contributes to about half of the Gravity Recovery And Climate Experiment (GRACE) total water storage variations. For the first time, we map the surface water volume anomaly during the extreme droughts of 1997 (October-November) and 2005 (September-October) and found that during these dry events the water stored in the river and flood-plains of the Amazon basin was, respectively, approx. 230 (approx. 40%) and 210 (approx. 50%) cu km below the 1993-2007 average. This new 15year data set of surface water volume represents an unprecedented source of information for future hydrological or climate modeling of the Amazon. It is also a first step toward the development of such database at the global scale.

  3. Doomed reservoirs in Kansas, USA? Climate change and groundwater mining on the Great Plains lead to unsustainable surface water storage

    Science.gov (United States)

    Brikowski, T. H.

    2008-06-01

    SummaryStreamflow declines on the Great Plains of the US are causing many Federal reservoirs to become profoundly inefficient, and will eventually drive them into unsustainability as negative annual reservoir water budgets become more common. The streamflow declines are historically related to groundwater mining, but since the mid-1980s correlate increasingly with climate. This study highlights that progression toward unsustainability, and shows that future climate change will continue streamflow declines at historical rates, with severe consequences for surface water supply. An object lesson is Optima Lake in the Oklahoma Panhandle, where streamflows have declined 99% since the 1960s and the reservoir has never been more than 5% full. Water balances for the four westernmost Federal reservoirs in Kansas (Cedar Bluff, Keith Sebelius, Webster and Kirwin) show similar tendencies. For these four, reservoir inflow has declined by 92%, 73%, 81% and 64% respectively since the 1950s. Since 1990 total evaporated volumes relative to total inflows amounted to 68%, 83%, 24% and 44% respectively. Predictions of streamflow and reservoir performance based on climate change models indicate 70% chance of steady decline after 2007, with a ˜50% chance of failure (releases by gravity flow impossible) of Cedar Bluff Reservoir between 2007 and 2050. Paradoxically, a 30% chance of storage increase prior 2020 is indicated, followed by steady declines through 2100. Within 95% confidence the models predict >50% decline in surface water resources between 2007 and 2050. Ultimately, surface storage of water resources may prove unsustainable in this region, forcing conversion to subsurface storage.

  4. Brief draft on surface and subsurface storage of high level and long-lived radioactive wastes. Spent fuels synthesis file

    International Nuclear Information System (INIS)

    Dumas, C.; Jaecki, P.

    2002-01-01

    This document makes a synthesis of the results of two brief draft studies performed in 2002 about the surface and subsurface storage of spent fuels. These studies stress on the long duration aspect of the disposal: feasibility of a secular disposal facility, potential risks and safety level of such a facility, estimation of the initial investment and of operation and maintenance costs. The main points of the specifications and the input data are presented first, and then the subsurface and surface draft studies are described. Content: specifications (imposed design principles and options, dry corrosion, input data); subsurface storage (description and design options, thermal dimensioning and ventilation, geotechnical stability of the facility, subsurface water management, dry corrosion, infrastructure durability, safety, monitoring, security and physical protection, technical-economical aspects, case of Mox fuel, case of glass packages); surface storage (description and design options, thermal dimensioning and ventilation, mechanical dimensioning of the facility, dry corrosion, infrastructure durability, safety, monitoring, security and physical protection, technical-economical aspects, case of Mox fuel, case of glass packages); conclusions and perspectives. (J.S.)

  5. He atom surface spectroscopy: Surface lattice dynamics of insulators, metals and metal overlayers

    International Nuclear Information System (INIS)

    1990-01-01

    During the first three years of this grant (1985--1988) the effort was devoted to the construction of a state-of-the-art He atom scattering (HAS) instrument which would be capable of determining the structure and dynamics of metallic, semiconductor or insulator crystal surfaces. The second three year grant period (1988--1991) has been dedicated to measurements. The construction of the instrument went better than proposed; it was within budget, finished in the proposed time and of better sensitivity and resolution than originally planned. The same success has been carried over to the measurement phase where the concentration has been on studies of insulator surfaces, as discussed in this paper. The experiments of the past three years have focused primarily on the alkali halides with a more recent shift to metal oxide crystal surfaces. Both elastic and inelastic scattering experiments were carried out on LiF, NaI, NaCl, RbCl, KBr, RbBr, RbI, CsF, CsI and with some preliminary work on NiO and MgO

  6. Near-surface eddy dynamics in the Southern Ocean

    Directory of Open Access Journals (Sweden)

    Marilisa Trani

    2011-12-01

    Full Text Available The Antarctic Circumpolar Current (ACC is a crucial component of the global ocean conveyor belt, acting as a zonal link among the major ocean basins but, to some extent, limiting meridional exchange and tending to isolate the ocean south of it from momentum and heat income. In this work we investigate one of the most important mechanisms contributing to the poleward transfer of properties in the Southern Ocean, that is the eddy component of the dynamics. For this particular purpose, observations obtained from near-surface drifters have been used: they represent a very useful data set to analyse the eddy field because of their ability to catch a large number of scales of motion while providing a quasi-synoptic coverage of the investigated area. Estimates of the eddy heat and momentum fluxes are carried out using data taken from the Global Drifter Program databank; they refer to Surface Velocity Program drifter trajectories collected in the area south of 35°S between 1995 and 2006. Eddy kinetic energies, variance ellipses, momentum and heat fluxes have been calculated using the pseudo-Eulerian method, showing patterns in good agreement with those present in the literature based on observational and model data, although there are some quantitative differences. The eddy fluxes have been separated into their rotational and divergent portions, the latter being responsible for the meridional transports. The associated zonal and depth-exponentially integrated meridional heat transport exhibits values spanning over a range between -0.4 PW and –1.1 PW in the ACC region, consistent with previous estimates.

  7. Second advanced ICFA beam dynamics workshop on aperture-related limitations of the performance and beam lifetime in storage rings

    International Nuclear Information System (INIS)

    Hagel, J.; Keil, E.

    1988-01-01

    These proceedings contain the papers presented at the 'Second advanced beam dynamics workshop on aperture-related limitations of the performance and beam lifetime in storage rings', which was organized in Lugano, Switzerland, from 11 to 16 April 1988, by the Beam Dynamics Panel of the International Committee for Future Accelerators (ICFA). The papers cover experiments on existing accelerators, analytical methods for determining amplitude limitations, criteria for the properties of the circulating beam and for the quality of accelerator components, and compensation schemes for field defects. (orig.)

  8. Assessing ecohydrological controls on catchment water storage, flux and age dynamics using tracers in a physically-based, spatially distributed model

    Science.gov (United States)

    Kuppel, S.; Tetzlaff, D.; Maneta, M. P.; Soulsby, C.

    2017-12-01

    Stable water isotope tracing has been extensively used in a wide range of geographical environments as a means to understand the sources, flow paths and ages of water stored and exiting a landscape via evapotranspiration, surface runoff and/or stream flow. Comparisons of isotopic signatures of precipitation and water in streams, soils, groundwater and plant xylem facilitates the assessment of how plant water use may affect preferential hydrologic pathways, storage dynamics and transit times in the critical zone. While tracers are also invaluable for testing model structure and accuracy, in most cases the measured isotopic signatures have been used to guide the calibration of conceptual runoff models with simplified vegetation and energy balance representation, which lacks sufficient detail to constrain key ecohydrological controls on flow paths and water ages. Here, we use a physically-based, distributed ecohydrological model (EcH2O) which we have extended to track 2H and 18O (including fractionation processes), and water age. This work is part of the "VeWa" project which aims at understanding ecohydrological couplings across climatic gradients in the wider North, where the hydrological implications of projected environmental change are essentially unknown though expected to be high. EcH2O combines a hydrologic scheme with an explicit representation of plant growth and phenology while resolving the energy balance across the soil-vegetation-atmosphere continuum. We focus on a montane catchment in Scotland, where unique long-term, high resolution hydrometric, ecohydrological and isotopic data allows for extensive model testing and projections. Results show the importance of incorporating soil fractionation processes to explain stream isotope dynamics, particularly seasonal enrichment in this humid, energy-limited catchment. This generic process-based approach facilitates analysis of dynamics in isotopes, storage and ages for the different hydrological compartments

  9. Satellite-derived surface and sub-surface water storage in the Ganges–Brahmaputra River Basin

    Directory of Open Access Journals (Sweden)

    Fabrice Papa

    2015-09-01

    New hydrological insights: Basin-scale monthly SWS variations for the period 2003–2007 show a mean annual amplitude of ∼410 km3, contributing to about 45% of the Gravity Recovery And Climate Experiment (GRACE-derived total water storage variations (TWS. During the drought-like conditions in 2006, we estimate that the SWS deficit over the entire GB basin in July–August–September was about 30% as compared to other years. The SWS variations are then used to decompose the GB GRACE-derived TWS and isolate the variations of SSWS whose mean annual amplitude is estimated to be ∼550 km3. This new dataset of water storage variations represent an unprecedented source of information for hydrological and climate modeling studies of the ISC.

  10. Dynamic sizing of energy storage for hedging wind power forecast uncertainty

    DEFF Research Database (Denmark)

    Pinson, Pierre; Papefthymiou, George; Klöckl, Bernd

    2009-01-01

    In market conditions where program responsible parties are penalized for deviations from proposed bids, energy storage can be used for compensating the energy imbalances induced by limited predictability of wind power. The energy storage capacity necessary for performing this task will differ bet...

  11. The hydrophobic effect: Molecular dynamics simulations of water confined between extended hydrophobic and hydrophilic surfaces

    DEFF Research Database (Denmark)

    Jensen, Morten Østergaard; Mouritsen, Ole G.; Peters, Günther H.J.

    2004-01-01

    Structural and dynamic properties of water confined between two parallel, extended, either hydrophobic or hydrophilic crystalline surfaces of n-alkane C36H74 or n-alcohol C35H71OH, are studied by molecular dynamics simulations. Electron density profiles, directly compared with corresponding......-correlation functions reveal that water molecules have characteristic diffusive behavior and orientational ordering due to the lack of hydrogen bonding interactions with the surface. These observations suggest that the altered dynamical properties of water in contact with extended hydrophobic surfaces together...... at both surfaces. The ordering is characteristically different between the surfaces and of longer range at the hydrophilic surface. Furthermore, the dynamic properties of water are different at the two surfaces and different from the bulk behavior. In particular, at the hydrophobic surface, time...

  12. Optodynamics: dynamic aspects of laser beam-surface interaction

    International Nuclear Information System (INIS)

    Možina, J; Diaci, J

    2012-01-01

    This paper presents a synthesis of the results of our original research in the area of laser-material interaction and pulsed laser material processing with a special emphasis on the dynamic aspects of laser beam-surface interaction, which include the links between the laser material removal and the resulting material motion. In view of laser material processing, a laser beam is not only considered as a tool but also as a generator of information about the material transformation. The information is retained and conveyed by different kinds of optically induced mechanical waves. Several generation/detection schemes have been developed to extract this information, especially in the field of non-destructive material evaluation. Blast and acoustic waves, which propagate in the air surrounding the work-piece, have been studied using microphone detection as well as various setups of the laser beam deflection probe. Stress waves propagating through the work-piece have been studied using piezoelectric transducers and laser interferometers.

  13. Validation of a laboratory method for evaluating dynamic properties of reconstructed equine racetrack surfaces.

    Directory of Open Access Journals (Sweden)

    Jacob J Setterbo

    Full Text Available Racetrack surface is a risk factor for racehorse injuries and fatalities. Current research indicates that race surface mechanical properties may be influenced by material composition, moisture content, temperature, and maintenance. Race surface mechanical testing in a controlled laboratory setting would allow for objective evaluation of dynamic properties of surface and factors that affect surface behavior.To develop a method for reconstruction of race surfaces in the laboratory and validate the method by comparison with racetrack measurements of dynamic surface properties.Track-testing device (TTD impact tests were conducted to simulate equine hoof impact on dirt and synthetic race surfaces; tests were performed both in situ (racetrack and using laboratory reconstructions of harvested surface materials. Clegg Hammer in situ measurements were used to guide surface reconstruction in the laboratory. Dynamic surface properties were compared between in situ and laboratory settings. Relationships between racetrack TTD and Clegg Hammer measurements were analyzed using stepwise multiple linear regression.Most dynamic surface property setting differences (racetrack-laboratory were small relative to surface material type differences (dirt-synthetic. Clegg Hammer measurements were more strongly correlated with TTD measurements on the synthetic surface than the dirt surface. On the dirt surface, Clegg Hammer decelerations were negatively correlated with TTD forces.Laboratory reconstruction of racetrack surfaces guided by Clegg Hammer measurements yielded TTD impact measurements similar to in situ values. The negative correlation between TTD and Clegg Hammer measurements confirms the importance of instrument mass when drawing conclusions from testing results. Lighter impact devices may be less appropriate for assessing dynamic surface properties compared to testing equipment designed to simulate hoof impact (TTD.Dynamic impact properties of race surfaces

  14. Response surface method optimization of V-shaped fin assisted latent heat thermal energy storage system during discharging process

    Directory of Open Access Journals (Sweden)

    Sina Lohrasbi

    2016-09-01

    Full Text Available Latent Heat Thermal Energy Storage Systems (LHTESS containing Phase Change Material (PCM are used to establish balance between energy supply and demand. PCMs have high latent heat but low thermal conductivity, which affects their heat transfer performance. In this paper, a novel fin array has been optimized by multi-objective Response Surface Method (RSM based on discharging process of PCM, and then this fin configuration is applied on LHTESS, and comparison between full discharging time by applying this fin array and LHTESS with other fin structures has been carried out. The employed numerical method in this paper is Standard Galerkin Finite Element Method. Adaptive grid refinement is used to solve the equations. Since the enhancement technique, which has been employed in the present study reduces the employed PCM mass, maximum energy storage capacity variations have been considered. Therefore phase change expedition and maximum energy storage capacity have been considered as the objectives of optimization and the importance of second objective is indicated which is proposed as the novelty here. Results indicate that considering maximum energy storage capacity as the objective of optimization procedure leads to efficient shape design of LHTESS. Also employing optimized V-shaped fin in LHTESS, expedites discharging process considerably in comparison with the LHTESS without fin.

  15. Functional response of a near-surface soil microbial community to a simulated underground CO2 storage leak.

    Science.gov (United States)

    Morales, Sergio E; Holben, William E

    2013-01-01

    Understanding the impacts of leaks from geologic carbon sequestration, also known as carbon capture and storage, is key to developing effective strategies for carbon dioxide (CO2) emissions management and mitigation of potential negative effects. Here, we provide the first report on the potential effects of leaks from carbon capture and storage sites on microbial functional groups in surface and near-surface soils. Using a simulated subsurface CO2 storage leak scenario, we demonstrate how CO2 flow upward through the soil column altered both the abundance (DNA) and activity (mRNA) of microbial functional groups mediating carbon and nitrogen transformations. These microbial responses were found to be seasonally dependent and correlated to shifts in atmospheric conditions. While both DNA and mRNA levels were affected by elevated CO2, they did not react equally, suggesting two separate mechanisms for soil microbial community response to high CO2 levels. The results did not always agree with previous studies on elevated atmospheric (rather than subsurface) CO2 using FACE (Free-Air CO2 Enrichment) systems, suggesting that microbial community response to CO2 seepage from the subsurface might differ from its response to atmospheric CO2 increases.

  16. Utilizing GNSS Reflectometry to Assess Surface Inundation Dynamics in Tropical Wetlands

    Science.gov (United States)

    Jensen, K.; McDonald, K. C.; Podest, E.; Chew, C. C.

    2017-12-01

    Tropical wetlands play a significant role in global atmospheric methane and terrestrial water storage. Despite the growing number of remote sensing products from satellite sensors, both spatial distribution and temporal variability of wetlands remain highly uncertain. An emerging innovative approach to mapping wetlands is offered by GNSS reflectometry (GNSS-R), a bistatic radar concept that takes advantage of GNSS transmitting satellites to yield observations with global coverage and rapid revisit time. This technology offers the potential to capture dynamic inundation changes in wetlands at higher temporal fidelity and sensitivity under the canopy than presently possible. We present an integrative analysis of radiometric modeling, ground measurements, and several microwave remote sensing datasets traditionally used for wetland observations. From a theoretical standpoint, GNSS-R sensitivities for vegetation and wetlands are investigated with a bistatic radar model in order to understand the interactions of the signal with various land surface components. GNSS reflections from the TechDemoSat-1 (TDS-1), Soil Moisture Active Passive (SMAP), and Cyclone GNSS (CYGNSS) missions are tested experimentally with contemporaneous (1) field measurements collected from the Pacaya Samiria National Reserve in the Peruvian Amazon, (2) imaging radar from Sentinel-1 and PALSAR-2 observed over a variety of tropical wetland systems, and (3) pan-tropical coarse-resolution (25km) microwave datasets (Surface Water Microwave Product Series). We find that GNSS-R data provide the potential to extend capabilities of current remote sensing techniques to characterize surface inundation extent, and we explore how to maximize synergism between different satellite sensors to produce an enhanced wetland monitoring product.

  17. Anthropogenic and geomorphic controls on peatland dynamics in contrasting floodplain environments during the Holocene and its impact on carbon storage

    Science.gov (United States)

    Verstraeten, Gert; Broothaerts, Nils; Notebaert, Bastiaan

    2016-04-01

    Peatlands are an important store of carbon in terrestrial environments, and scientific interest in peatlands has increased strongly in the light of the recent global climatic changes. Much attention has been paid to peatland dynamics in extensive arctic and boreal wetlands or to blanket peat in temperate regions. Nevertheless, long-term dynamics of peat in alluvial wetlands in temperate regions remains largely underresearched. In this study, data from three contrasting environments were used to provide more insights in the anthropogenic and geomorphic controls on peatland dynamics. The results show a high variability in alluvial peatland dynamics between the different study sites. In the central Belgian Loess Belt, alluvial peatlands developed during the early Holocene but gradually disappeared from the Mid-Holocene onwards due to the gradual intensification of agricultural activities in the catchment and consequent higher sedimentation rates in the floodplain system. The end of peat growth is shown to be diachronous at catchment scale, ranging between 6500 and 500 cal a BP. The disappearance of the alluvial peatlands has important implications since it potentially reduces the storage of locally produced C. Nevertheless, it was shown that this reduced production of local C but was outbalanced by the burial of hillslope derived C. Also within the sandy catchments of the Belgian Campine region alluvial peatlands initiated in the early Holocene but, here, they abruptly disappeared in the Mid-Holocene before the onset of intense agricultural activities in the catchment. This suggests that for the sandy regions, anthropogenic impact on peatland dynamics is less important compared to natural factors. For these regions, the disappearance of alluvial peatland formation resulted in a sharp decline in alluvial carbon storage as there is no compensation through hillslope derived C input. For the upper Dee catchment in NE Scotland, Holocene carbon floodplain storage varies

  18. Interfacial Interactions and Wettability Evaluation of Rock Surfaces for CO2 Storage

    NARCIS (Netherlands)

    Shojai Kaveh, N.

    2014-01-01

    To reduce CO2 emissions into the atmosphere, different scenarios are proposed to capture and store carbon dioxide (CO2) in geological formations (CCS). Storage strategies include CO2 injection into deep saline aquifers, depleted gas and oil reservoirs, and unmineable coal seams. To identify a secure

  19. Improvement of the variable storage coefficient method with water surface gradient as a variable

    Science.gov (United States)

    The variable storage coefficient (VSC) method has been used for streamflow routing in continuous hydrological simulation models such as the Agricultural Policy/Environmental eXtender (APEX) and the Soil and Water Assessment Tool (SWAT) for more than 30 years. APEX operates on a daily time step and ...

  20. Understanding surface-water availability in the Central Valley as a means to projecting future groundwater storage with climate variability

    Science.gov (United States)

    Goodrich, J. P.; Cayan, D. R.

    2017-12-01

    California's Central Valley (CV) relies heavily on diverted surface water and groundwater pumping to supply irrigated agriculture. However, understanding the spatiotemporal character of water availability in the CV is difficult because of the number of individual farms and local, state, and federal agencies involved in using and managing water. Here we use the Central Valley Hydrologic Model (CVHM), developed by the USGS, to understand the relationships between climatic variability, surface water inputs, and resulting groundwater use over the historical period 1970-2013. We analyzed monthly surface water diversion data from >500 CV locations. Principle components analyses were applied to drivers constructed from meteorological data, surface reservoir storage, ET, land use cover, and upstream inflows, to feed multiple regressions and identify factors most important in predicting surface water diversions. Two thirds of the diversion locations ( 80% of total diverted water) can be predicted to within 15%. Along with monthly inputs, representations of cumulative precipitation over the previous 3 to 36 months can explain an additional 10% of variance, depending on location, compared to results that excluded this information. Diversions in the southern CV are highly sensitive to inter-annual variability in precipitation (R2 = 0.8), whereby more surface water is used during wet years. Until recently, this was not the case in the northern and mid-CV, where diversions were relatively constant annually, suggesting relative insensitivity to drought. In contrast, this has important implications for drought response in southern regions (eg. Tulare Basin) where extended dry conditions can severely limit surface water supplies and lead to excess groundwater pumping, storage loss, and subsidence. In addition to fueling our understanding of spatiotemporal variability in diversions, our ability to predict these water balance components allows us to update CVHM predictions before

  1. Privacy-Preserving Outsourced Auditing Scheme for Dynamic Data Storage in Cloud

    OpenAIRE

    Tu, Tengfei; Rao, Lu; Zhang, Hua; Wen, Qiaoyan; Xiao, Jia

    2017-01-01

    As information technology develops, cloud storage has been widely accepted for keeping volumes of data. Remote data auditing scheme enables cloud user to confirm the integrity of her outsourced file via the auditing against cloud storage, without downloading the file from cloud. In view of the significant computational cost caused by the auditing process, outsourced auditing model is proposed to make user outsource the heavy auditing task to third party auditor (TPA). Although the first outso...

  2. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    International Nuclear Information System (INIS)

    Kovalenko, Oleksandr

    2015-01-01

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U 90+ beam at the existing storage ring ESR, GSI.

  3. Ion optics and beam dynamics optimization at the HESR storage ring for the SPARC experiments with highly charged heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Kovalenko, Oleksandr

    2015-06-24

    The High-Energy Storage Ring (HESR) is a part of an upcoming International Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt. A key part of a scientific program, along with antiproton physics, will be physics with highly-charged heavy ions. Phase-space cooled beams together with fixed internal target will provide an excellent environment for storage ring experiments at the HESR for the SPARC collaboration. Until recently, however, the existing ion optical lattice for the HESR was designed only for the experiments with antiproton beams. The thesis presents a new ion optical mode developed specifically for the operation of the HESR with highly charged heavy ions. The presence of the errors, such as beam momentum spread, magnetic field impurities or magnets misalignments, leads to disruption of beam dynamics: exciting of resonant motion and loss of beam stability. Within the paper, these effects are investigated with the help of numerical codes for particle accelerator design and simulation MAD-X and MIRKO. A number of correction techniques are applied to minimize the nonlinear impact on the beam dynamics and improve the experimental conditions. The application of the analytical and numerical tools is demonstrated in the experiment with uranium U{sup 90+} beam at the existing storage ring ESR, GSI.

  4. THE INFLUENCE OF AEROSOL GAS-DYNAMIC SUSPENSION CLEANING ON SURFACE OF THE AIRCRAFT PARTS

    Directory of Open Access Journals (Sweden)

    Vitaly D. Hizhko

    2008-02-01

    Full Text Available  The specificity of the surface microgeometry formation under the influence of aerosol gas-dynamic suspension flow was considered. The composition and character of metallic surface layer formation of aircraft parts was investigated. The possibility of surface material composition and properties adjustment changing aerosol gas-dynamic suspension flow parameters was determined. The hypothesis about the possibility of using aerosol gas-dynamic suspension flow to form corrosion-resistant coating on the detail metallic surfaces was set up.

  5. Effect of water storage and surface treatments on the tensile bond strength of IPS Empress 2 ceramic.

    Science.gov (United States)

    Salvio, Luciana A; Correr-Sobrinho, Lourenço; Consani, Simonides; Sinhoreti, Mário A C; de Goes, Mario F; Knowles, Jonathan C

    2007-01-01

    The aim of this study was to evaluate the effect of water storage (24 hours and 1 year) on the tensile bond strength between the IPS Empress 2 ceramic and Variolink II resin cement under different superficial treatments. One hundred and eighty disks with diameters of 5.3 mm at the top and 7.0 mm at the bottom, and a thickness of 2.5 mm were made, embedded in resin, and randomly divided into six groups: Groups 1 and 4 = 10% hydrofluoric acid for 20 seconds; Groups 2 and 5 = sandblasting for 5 seconds with 50 microm aluminum oxide; and Groups 3 and 6 = sandblasting for 5 seconds with 100 microm aluminum oxide. Silane was applied on the treated ceramic surfaces, and the disks were bonded into pairs with adhesive resin cement. The samples of Groups 1 to 3 were stored in distilled water at 37 degrees C for 24 hours, and Groups 4 to 6 were stored for 1 year. The samples were subjected to a tensile strength test in an Instron universal testing machine at a crosshead speed of 1.0 mm/min, until failure. The data were submitted to analysis of variance and Tukey's test (5%). The means of the tensile bond strength of Groups 1, 2, and 3 (15.54 +/- 4.53, 10.60 +/- 3.32, and 7.87 +/- 2.26 MPa) for 24-hour storage time were significantly higher than those observed for the 1-year storage (Groups 4, 5, and 6: 10.10 +/- 3.17, 6.34 +/- 1.06, and 2.60 +/- 0.41 MPa). The surface treatments with 10% hydrofluoric acid (15.54 +/- 4.53 and 10.10 +/- 3.17 MPa) showed statistically higher tensile bond strengths compared with sandblasting with 50 microm(10.60 +/- 3.32 and 6.34 +/- 1.06 MPa) and 100 microm (7.87 +/- 2.26 and 2.60 +/- 0.41 MPa) aluminum oxide for the storage time 24 hours and 1 year. Storage time significantly decreased the tensile bond strength for both ceramic surface treatments. The application of 10% hydrofluoric acid resulted in stronger tensile bond strength values than those achieved with aluminum oxide.

  6. Storage Rings

    International Nuclear Information System (INIS)

    Fischer, W.

    2010-01-01

    . Storage rings have instrumentation to monitor the electrical and mechanical systems, and the beam quality. Computers are used to control the operation. Large storage rings have millions of control points from all systems. The time dependent beam intensity I(t) can often be approximated by an exponential function I(t) = I(0) exp(-t/τ) (1) where the decay time τ and, correspondingly, the store time ranges from a few turns to 10 days (ISR). τ can be dominated by a variety of effects including lattice nonlinearities, beam-beam, space charge, intrabeam and Touschek scattering, interaction with the residual gas or target, or the lifetime of the stored particle. In this case, the beam lifetime measurement itself can be the purpose of a storage ring experiment. The main consideration in the design of a storage ring is the preservation of the beam quality over the store length. The beam size and momentum spread can be reduced through cooling, often leading to an increase in the store time. For long store times vacuum considerations are important since the interaction rate of the stored particles with the residual gas molecules is proportional to the pressure, and an ultra-high vacuum system may be needed. Distributed pumping with warm activated NEG surfaces or cold surfaces in machines with superconducting magnets are ways to provide large pumping speeds and achieve low pressures even under conditions with dynamic gas loads. The largest application of storage rings today are synchrotron light sources, of which about 50 exist world wide. In experiments where the beam collides with an internal target or another beam, a storage ring allows to re-use the accelerated beam many times if the interaction with the target is sufficiently small. In hadron collider and ion storage rings store times of many hours or even days are realized, corresponding to up to 1011 turns and thereby target passages. Ref. (3) is the first proposal for a collider storage ring. A number of storage rings

  7. Atomistic interactions of clusters on surfaces using molecular dynamics and hyper molecular dynamics

    International Nuclear Information System (INIS)

    Sanz-Navarro, Carlos F.

    2002-01-01

    The work presented in this thesis describes the results of Molecular Dynamics (MD) simulations applied to the interaction of silver clusters with graphite surfaces and some numerical and theoretical methods concerning the extension of MD simulations to longer time scales (hyper-MD). The first part of this thesis studies the implantation of clusters at normal incidence onto a graphite surface in order to determine the scaling of the penetration depth (PD) against the impact energy. A comparison with experimental results is made with good agreement. The main physical observations of the impact process are described and analysed. It is shown that there is a threshold impact velocity above which the linear dependence on PD on impact energy changes to a linear dependence on velocity. Implantation of silver clusters at oblique incidence is also considered. The second part of this work analyses the validity and feasibility of the three minimisation methods for the hyper-MD simulation method whereby time scales of an MD simulation can be extended. A correct mathematical basis for the iterative method is derived. It is found that one of the iterative methods, upon which hyper-lD is based, is very likely to fail in high-dimensional situations because it requires a too expensive convergence. Two new approximations to the hyper-MD approach are proposed, which reduce the computational effort considerably. Both approaches, although not exact, can help to search for some of the most likely transitions in the system. Some examples are given to illustrate this. (author)

  8. Surface-downhole and crosshole geoelectrics for monitoring of brine injection at the Ketzin CO2 storage site

    Science.gov (United States)

    Rippe, Dennis; Bergmann, Peter; Labitzke, Tim; Wagner, Florian; Schmidt-Hattenberger, Cornelia

    2016-04-01

    The Ketzin pilot site in Germany is the longest operating on-shore CO2 storage site in Europe. From June 2008 till August 2013, a total of ˜67,000 tonnes of CO2 were safely stored in a saline aquifer at depths of 630 m to 650 m. The storage site has now entered the abandonment phase, and continuation of the multi-disciplinary monitoring as part of the national project "CO2 post-injection monitoring and post-closure phase at the Ketzin pilot site" (COMPLETE) provides the unique chance to participate in the conclusion of the complete life cycle of a CO2 storage site. As part of the continuous evaluation of the functionality and integrity of the CO2 storage in Ketzin, from October 12, 2015 till January 6, 2015 a total of ˜2,900 tonnes of brine were successfully injected into the CO2 reservoir, hereby simulating in time-lapse the natural backflow of brine and the associated displacement of CO2. The main objectives of this brine injection experiment include investigation of how much of the CO2 in the pore space can be displaced by brine and if this displacement of CO2 during the brine injection differs from the displacement of formation fluid during the initial CO2 injection. Geophysical monitoring of the brine injection included continuous geoelectric measurements accompanied by monitoring of pressure and temperature conditions in the injection well and two adjacent observation wells. During the previous CO2 injection, the geoelectrical monitoring concept at the Ketzin pilot site consisted of permanent crosshole measurements and non-permanent large-scale surveys (Kiessling et al., 2010). Time-lapse geoelectrical tomographies derived from the weekly crosshole data at near-wellbore scale complemented by six surface-downhole surveys at a scale of 1.5 km showed a noticeable resistivity signature within the target storage zone, which was attributed to the CO2 plume (Schmidt-Hattenberger et al., 2011) and interpreted in terms of relative CO2 and brine saturations (Bergmann

  9. Dynamic surface tension measurements of ionic surfactants using maximum bubble pressure tensiometry

    Science.gov (United States)

    Ortiz, Camilla U.; Moreno, Norman; Sharma, Vivek

    Dynamic surface tension refers to the time dependent variation in surface tension, and is intimately linked with the rate of mass transfer of a surfactant from liquid sub-phase to the interface. The diffusion- or adsorption-limited kinetics of mass transfer to interfaces is said to impact the so-called foamability and the Gibbs-Marangoni elasticity of surfaces. Dynamic surface tension measurements carried out with conventional methods like pendant drop analysis, Wilhelmy plate, etc. are limited in their temporal resolution (>50 ms). In this study, we describe design and application of maximum bubble pressure tensiometry for the measurement of dynamic surface tension effects at extremely short (1-50 ms) timescales. Using experiments and theory, we discuss the overall adsorption kinetics of charged surfactants, paying special attention to the influence of added salt on dynamic surface tension.

  10. Computational Fluid Dynamics Model for Solar Thermal Storage Tanks with Helical Jacket Heater and Upper Spiral Coil Heater

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Seung Man [Seoul Nat' l Univ., Seoul (Korea, Republic of); Zhong, Yiming; Nam, Jin Hyun [Daegu Univ., Daegu (Korea, Republic of); Chung, Jae Dong [Sejong Univ., Seoul (Korea, Republic of); Hong, Hiki [Kyung Hee Univ., Seoul (Korea, Republic of)

    2013-04-15

    In a solar domestic hot water (Shadow) system, solar energy is collected using collector panels, transferred to a circulating heat transfer fluid (brine), and eventually stored in a thermal storage tank (Test) as hot water. In this study, a computational fluid dynamics (CAD) model was developed to predict the solar thermal energy storage in a hybrid type Test equipped with a helical jacket heater (mantle heat exchanger) and an immersed spiral coil heater. The helical jacket heater, which is the brine flow path attached to the side wall of a Test, has advantages including simple system design, low brine flow rate, and enhanced thermal stratification. In addition, the spiral coil heater further enhances the thermal performance and thermal stratification of the Test. The developed model was validated by the good agreement between the CAD results and the experimental results performed with the hybrid-type Test in Shadow settings.

  11. Computational Fluid Dynamics Model for Solar Thermal Storage Tanks with Helical Jacket Heater and Upper Spiral Coil Heater

    International Nuclear Information System (INIS)

    Baek, Seung Man; Zhong, Yiming; Nam, Jin Hyun; Chung, Jae Dong; Hong, Hiki

    2013-01-01

    In a solar domestic hot water (Shadow) system, solar energy is collected using collector panels, transferred to a circulating heat transfer fluid (brine), and eventually stored in a thermal storage tank (Test) as hot water. In this study, a computational fluid dynamics (CAD) model was developed to predict the solar thermal energy storage in a hybrid type Test equipped with a helical jacket heater (mantle heat exchanger) and an immersed spiral coil heater. The helical jacket heater, which is the brine flow path attached to the side wall of a Test, has advantages including simple system design, low brine flow rate, and enhanced thermal stratification. In addition, the spiral coil heater further enhances the thermal performance and thermal stratification of the Test. The developed model was validated by the good agreement between the CAD results and the experimental results performed with the hybrid-type Test in Shadow settings

  12. Dynamic Response Analysis of Storage Cask Lid Structure Subjected to Lateral Impact Load of Aircraft Engine Crash

    International Nuclear Information System (INIS)

    Almomania, Belal; Kang, Hyun Gook; Lee, Sanghoon

    2015-01-01

    Several numerical methods and tests have been carried out to measure the capability of storage cask to withstand extreme impact loads. Testing methods are often constrained by cost, and difficulty in preparation for several impact conditions with different applied loads, and areas of impact. Instead, analytic method is an acceptable process that can easily apply different impact conditions for the evaluation of cask integrity. The aircraft engine impact is considered as one of the most critical impact accidents on the storage cask that significantly affects onto the lid closure system and may cause a considerable release of radioactive materials. This paper presents a method for evaluating the dynamic responses of one upper metal cask lid closure without impact limiters subjected to lateral impact of an aircraft engine with respect to variation of the impact velocity. An assessment method to predict damage response due to the lateral engine impact onto metal storage cask has been studied by using computer code LS-DYNA. The dynamic behavior of the lid movements was successfully calculated by utilizing a simplified finite element cask model, which showed a good agreement with the previous research. The simulation analyses results showed that no significant plastic deformation for bolts, lid, and the cask body. In this study, the lid opening and sliding displacements are considered as the major factors in initiating the leakage path. This analysis may be useful for evaluating the instantaneous leakage rates in a connection with the sliding and opening displacements between the lid and the flange to ensure that the radiological consequences caused by an aircraft engine crash accident during the storage phase are within the permissible level

  13. Dynamic Response Analysis of Storage Cask Lid Structure Subjected to Lateral Impact Load of Aircraft Engine Crash

    Energy Technology Data Exchange (ETDEWEB)

    Almomania, Belal; Kang, Hyun Gook [KAIST, Daejeon (Korea, Republic of); Lee, Sanghoon [Keimyung Univ., Daegu (Korea, Republic of)

    2015-10-15

    Several numerical methods and tests have been carried out to measure the capability of storage cask to withstand extreme impact loads. Testing methods are often constrained by cost, and difficulty in preparation for several impact conditions with different applied loads, and areas of impact. Instead, analytic method is an acceptable process that can easily apply different impact conditions for the evaluation of cask integrity. The aircraft engine impact is considered as one of the most critical impact accidents on the storage cask that significantly affects onto the lid closure system and may cause a considerable release of radioactive materials. This paper presents a method for evaluating the dynamic responses of one upper metal cask lid closure without impact limiters subjected to lateral impact of an aircraft engine with respect to variation of the impact velocity. An assessment method to predict damage response due to the lateral engine impact onto metal storage cask has been studied by using computer code LS-DYNA. The dynamic behavior of the lid movements was successfully calculated by utilizing a simplified finite element cask model, which showed a good agreement with the previous research. The simulation analyses results showed that no significant plastic deformation for bolts, lid, and the cask body. In this study, the lid opening and sliding displacements are considered as the major factors in initiating the leakage path. This analysis may be useful for evaluating the instantaneous leakage rates in a connection with the sliding and opening displacements between the lid and the flange to ensure that the radiological consequences caused by an aircraft engine crash accident during the storage phase are within the permissible level.

  14. Mapping Carrier Dynamics on Material Surfaces in Space and Time using Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya

    2016-02-25

    Selectively capturing the ultrafast dynamics of charge carriers on materials surfaces and at interfaces is crucial to the design of solar cells and optoelectronic devices. Despite extensive research efforts over the past few decades, information and understanding about surface-dynamical processes, including carrier trapping and recombination remains extremely limited. A key challenge is to selectively map such dynamic processes, a capability that is hitherto impractical by time-resolved laser techniques, which are limited by the laser’s relatively large penetration depth and consequently they record mainly bulk information. Such surface dynamics can only be mapped in real space and time by applying four-dimensional (4D) scanning ultrafast electron microscopy (S-UEM), which records snapshots of materials surfaces with nanometer spatial and sub-picosecond temporal resolutions. In this method, the secondary electron (SE) signal emitted from the sample’s surface is extremely sensitive to the surface dynamics and is detected in real time. In several unique applications, we spatially and temporally visualize the SE energy gain and loss, the charge carrier dynamics on the surface of InGaN nanowires and CdSe single crystals and its powder film. We also provide the mechanisms for the observed dynamics, which will be the foundation for future potential applications of S-UEM to a wide range of studies on material surfaces and device interfaces.

  15. Mapping Carrier Dynamics on Material Surfaces in Space and Time using Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya; Adhikari, Aniruddha; Shaheen, Basamat; Yang, Haoze; Mohammed, Omar F.

    2016-01-01

    Selectively capturing the ultrafast dynamics of charge carriers on materials surfaces and at interfaces is crucial to the design of solar cells and optoelectronic devices. Despite extensive research efforts over the past few decades, information and understanding about surface-dynamical processes, including carrier trapping and recombination remains extremely limited. A key challenge is to selectively map such dynamic processes, a capability that is hitherto impractical by time-resolved laser techniques, which are limited by the laser’s relatively large penetration depth and consequently they record mainly bulk information. Such surface dynamics can only be mapped in real space and time by applying four-dimensional (4D) scanning ultrafast electron microscopy (S-UEM), which records snapshots of materials surfaces with nanometer spatial and sub-picosecond temporal resolutions. In this method, the secondary electron (SE) signal emitted from the sample’s surface is extremely sensitive to the surface dynamics and is detected in real time. In several unique applications, we spatially and temporally visualize the SE energy gain and loss, the charge carrier dynamics on the surface of InGaN nanowires and CdSe single crystals and its powder film. We also provide the mechanisms for the observed dynamics, which will be the foundation for future potential applications of S-UEM to a wide range of studies on material surfaces and device interfaces.

  16. Storage Effects on Sample Integrity of Environmental Surface Sampling Specimens with Bacillus anthracis Spores.

    Science.gov (United States)

    Perry, K Allison; O'Connell, Heather A; Rose, Laura J; Noble-Wang, Judith A; Arduino, Matthew J

    The effect of packaging, shipping temperatures and storage times on recovery of Bacillus anthracis . Sterne spores from swabs was investigated. Macrofoam swabs were pre-moistened, inoculated with Bacillus anthracis spores, and packaged in primary containment or secondary containment before storage at -15°C, 5°C, 21°C, or 35°C for 0-7 days. Swabs were processed according to validated Centers for Disease Control/Laboratory Response Network culture protocols, and the percent recovery relative to a reference sample (T 0 ) was determined for each variable. No differences were observed in recovery between swabs held at -15° and 5°C, (p ≥ 0.23). These two temperatures provided significantly better recovery than swabs held at 21°C or 35°C (all 7 days pooled, p ≤ 0.04). The percent recovery at 5°C was not significantly different if processed on days 1, 2 or 4, but was significantly lower on day 7 (day 2 vs. 7, 5°C, 10 2 , p=0.03). Secondary containment provided significantly better percent recovery than primary containment, regardless of storage time (5°C data, p ≤ 0.008). The integrity of environmental swab samples containing Bacillus anthracis spores shipped in secondary containment was maintained when stored at -15°C or 5°C and processed within 4 days to yield the optimum percent recovery of spores.

  17. A Simple Operating Strategy of Small-Scale Battery Energy Storages for Energy Arbitrage under Dynamic Pricing Tariffs

    Directory of Open Access Journals (Sweden)

    Enrico Telaretti

    2015-12-01

    Full Text Available Price arbitrage involves taking advantage of an electricity price difference, storing electricity during low-prices times, and selling it back to the grid during high-prices periods. This strategy can be exploited by customers in presence of dynamic pricing schemes, such as hourly electricity prices, where the customer electricity cost may vary at any hour of day, and power consumption can be managed in a more flexible and economical manner, taking advantage of the price differential. Instead of modifying their energy consumption, customers can install storage systems to reduce their electricity bill, shifting the energy consumption from on-peak to off-peak hours. This paper develops a detailed storage model linking together technical, economic and electricity market parameters. The proposed operating strategy aims to maximize the profit of the storage owner (electricity customer under simplifying assumptions, by determining the optimal charge/discharge schedule. The model can be applied to several kinds of storages, although the simulations refer to three kinds of batteries: lead-acid, lithium-ion (Li-ion and sodium-sulfur (NaS batteries. Unlike literature reviews, often requiring an estimate of the end-user load profile, the proposed operation strategy is able to properly identify the battery-charging schedule, relying only on the hourly price profile, regardless of the specific facility’s consumption, thanks to some simplifying assumptions in the sizing and the operation of the battery. This could be particularly useful when the customer load profile cannot be scheduled with sufficient reliability, because of the uncertainty inherent in load forecasting. The motivation behind this research is that storage devices can help to lower the average electricity prices, increasing flexibility and fostering the integration of renewable sources into the power system.

  18. Structural Changes in the Surface of Red Blood Cell Membranes during Long-Term Donor Blood Storage

    Directory of Open Access Journals (Sweden)

    V. V. Moroz

    2012-01-01

    Full Text Available Objective: to study changes in the surface of red blood cell membranes of donor blood at the macro- and ultrastructural level during its storage for 30 days and to evaluate the functional state of the red blood cell membrane during the whole storage period. Material and methods. The investigation was conducted on human whole blood and packed red blood cells placed in the specialized packs containing the preservative CPDA-1, by using calibrated electroporation and atomic force microscopy and measuring plasma pH. Conclusion. The long-term, up to 30-day, storage of whole blood and packed red blood cells at 4°C was attended by lower plasma pH and increased hemolysis rate constant during calibrated electroporation and by the development of oxidative processes. The hemolysis rate constant was also higher in the packed red blood cells than that in the whole blood. On days 5—6, the membrane structure showed defects that developed, as the blood was stored, and caused irreversible cell membrane damage by day 30. Key words: donor blood, red blood cell membranes, atomic force microscopy.

  19. StorNet: Integrated Dynamic Storage and Network Resource Provisioning and Management for Automated Data Transfers

    International Nuclear Information System (INIS)

    Gu Junmin; Natarajan, Vijaya; Shoshani, Arie; Sim, Alex; Katramatos, Dimitrios; Liu Xin; Yu Dantong; Bradley, Scott; McKee, Shawn

    2011-01-01

    StorNet is a joint project of Brookhaven National Laboratory (BNL) and Lawrence Berkeley National Laboratory (LBNL) to research, design, and develop an integrated end-to-end resource provisioning and management framework for high-performance data transfers. The StorNet framework leverages heterogeneous network protocols and storage types in a federated computing environment to provide the capability of predictable, efficient delivery of high-bandwidth data transfers for data intensive applications. The framework incorporates functional modules to perform such data transfers through storage and network bandwidth co-scheduling, storage and network resource provisioning, and performance monitoring, and is based on LBNL's BeStMan/SRM, BNL's TeraPaths, and ESNet's OSCARS systems.

  20. Assessment of Dynamic Flow, Pressure and Geomechanical Behaviour of a CO2 Storage Complex

    DEFF Research Database (Denmark)

    Mbia, Ernest Ncha; Frykman, Peter

    dioxide (CO2) is the primary greenhouse gas emitted through human activities. Over 7,500 large CO2 emission sources (above 0.1 million tons CO2 year-1) have been identified (IPCC, 2005). These sources are distributed geographically around the world but four clusters of emissions can be observed: in North......-fired power plants) and injecting it into deep formations (e.g., saline aquifers, oil and gas reservoirs, and coalbeds) for storage. This process has drawn increasing consideration as a promising mitigation method that is economically possible. Deep saline aquifers offer the largest storage potential of all...

  1. Dynamics in the microbiology of maize silage during whole-season storage

    DEFF Research Database (Denmark)

    Storm, Ida Marie Lindhardt Drejer; Kristensen, N.B.; Raun, B.M.L.

    2010-01-01

    Aims: To monitor seasonal variations in the microbiology of maize silage and to determine whether the risk of fungal spoilage varies during whole-year storage. Methods and Results: A continuous survey of 20 maize silage stacks was conducted over a period from three to 11 months after ensiling...... variations in the microbiology of maize silage over a whole storage season. The risk of fungal spoilage was highest 5-7 months after ensiling and lowest after 11 months. Significance and Impact of the Study: This information is valuable in the assessment of health risks connected with spoiled maize silage...

  2. Three-dimensional ordering of cold ion beams in a storage ring: A molecular-dynamics simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Yuri, Yosuke, E-mail: yuri.yosuke@jaea.go.jp [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi Takasaki, Gunma 370-1292 Japan (Japan)

    2015-06-29

    Three-dimensional (3D) ordering of a charged-particle beams circulating in a storage ring is systematically studied with a molecular-dynamics simulation code. An ion beam can exhibit a 3D ordered configuration at ultralow temperature as a result of powerful 3D laser cooling. Various unique characteristics of the ordered beams, different from those of crystalline beams, are revealed in detail, such as the single-particle motion in the transverse and longitudinal directions, and the dependence of the tune depression and the Coulomb coupling constant on the operating points.

  3. A tri-objective, dynamic weapon assignment model for surface ...

    African Journals Online (AJOL)

    2015-05-11

    May 11, 2015 ... metaheuristic for solving the vehicle routing problem with time .... them the dynamic programming formulation by Bradford [3] in 1961, the nonlinear pro- ..... The concept of multi-objective optimisation naturally gives rise to the ...

  4. Dynamic of the vapor near an evaporating surface

    International Nuclear Information System (INIS)

    Anders, A.; Anders, S.; Timofeev, I.B.; Yusupaliev, U.

    1987-01-01

    The electrical characteristics of a plasma-dynamic accelerator with a gas fill are studied. The dynamics of a dense plasma jet in air at atmospheric pressure was studied with the help of ultrafast photography and the schlieren technique. It is shown that for impulsive injection of a dense plasma jet into the atmosphere a spherical shock wave and a cloud of intensely radiating plasma, from which under certain conditions a stable long-lived toroidal or spherical plasma configuration forms, are produced

  5. New model for surface fracture induced by dynamical stress

    OpenAIRE

    Andersen, J. V.; Lewis, L. J.

    1997-01-01

    We introduce a model where an isotropic, dynamically-imposed stress induces fracture in a thin film. Using molecular dynamics simulations, we study how the integrated fragment distribution function depends on the rate of change and magnitude of the imposed stress, as well as on temperature. A mean-field argument shows that the system becomes unstable for a critical value of the stress. We find a striking invariance of the distribution of fragments for fixed ratio of temperature and rate of ch...

  6. Analysis of Samples Collected from the Surface of Interim Storage Canisters at Calvert Cliffs in June 2017: Revision 01.

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Charles R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schindelholz, Eric John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-11-01

    In June 2017, dust and salt samples were collected from the surface of Spent Nuclear Fuel (SNF) dry storage canisters at the Calvert Cliffs Nuclear Power Plant. The samples were delivered to Sandia National laboratories for analysis. Two types of samples were collected: filter-backed Scotch-Brite TM pads were used to collect dry dust samples for characterization of salt and dust morphologies and distributions; and Saltsmart TM test strips were used to collect soluble salts for determining salt surface loadings per unit area. After collection, the samples were sealed into plastic sleeves for shipping. Condensation within the sleeves containing the Scotch-Brite TM samples remobilized the salts, rendering them ineffective for the intended purpose, and also led to mold growth, further compromising the samples; for these reasons, the samples were not analyzed. The SaltSmart TM samples were unaffected and were analyzed by ion chromatography for major anions and cations. The results of those analyses are presented here.

  7. Meltwater storage in low-density near-surface bare ice in the Greenland ice sheet ablation zone

    Science.gov (United States)

    Cooper, Matthew G.; Smith, Laurence C.; Rennermalm, Asa K.; Miège, Clément; Pitcher, Lincoln H.; Ryan, Jonathan C.; Yang, Kang; Cooley, Sarah W.

    2018-03-01

    We document the density and hydrologic properties of bare, ablating ice in a mid-elevation (1215 m a.s.l.) supraglacial internally drained catchment in the Kangerlussuaq sector of the western Greenland ice sheet. We find low-density (0.43-0.91 g cm-3, μ = 0.69 g cm-3) ice to at least 1.1 m depth below the ice sheet surface. This near-surface, low-density ice consists of alternating layers of water-saturated, porous ice and clear solid ice lenses, overlain by a thin (sheet ablation zone surface. A conservative estimate for the ˜ 63 km2 supraglacial catchment yields 0.009-0.012 km3 of liquid meltwater storage in near-surface, porous ice. Further work is required to determine if these findings are representative of broader areas of the Greenland ice sheet ablation zone, and to assess the implications for sub-seasonal mass balance processes, surface lowering observations from airborne and satellite altimetry, and supraglacial runoff processes.

  8. Dynamic Water Storage during Flash Flood Events in the Mountainous Area of Rio de Janeiro/Brazil - Case study: Piabanha River Basin

    Science.gov (United States)

    Araujo, L.; Silva, F. P. D.; Moreira, D. M.; Vásquez P, I. L.; Justi da Silva, M. G. A.; Fernandes, N.; Rotunno Filho, O. C.

    2017-12-01

    Flash floods are characterized by a rapid rise in water levels, high flow rates and large amounts of debris. Several factors have relevance to the occurrence of these phenomena, including high precipitation rates, terrain slope, soil saturation degree, vegetation cover, soil type, among others. In general, the greater the precipitation intensity, the more likely is the occurrence of a significant increase in flow rate. Particularly on steep and rocky plains or heavily urbanized areas, relatively small rain rates can trigger a flash flood event. In addition, high rain rates in short time intervals can temporarily saturate the surface soil layer acting as waterproofing and favoring the occurrence of greater runoff rates due to non-infiltration of rainwater into the soil. Thus, although precipitation is considered the most important factor for flooding, the interaction between rainfall and the soil can sometimes be of greater importance. In this context, this work investigates the dynamic storage of water associated with flash flood events for Quitandinha river watershed, a tributary of Piabanha river, occurred between 2013 and 2014, by means of water balance analyses applied to three watersheds of varying magnitudes (9.25 km², 260 km² and 429 km²) along the rainy season under different time steps (hourly and daily) using remotely sensed and observational precipitation data. The research work is driven by the hypothesis of a hydrologically active bedrock layer, as the watershed is located in a humid region, having intemperate (fractured) rock layer, just below a shallow soil layer, in the higher part of the basin where steep slopes prevail. The results showed a delay of the variation of the dynamic storage in relation to rainfall peaks and water levels. Such behavior indicates that the surface soil layer, which is not very thick in the region, becomes rapidly saturated along rainfall events. Subsequently, the water infiltrates into the rocky layer and the water

  9. Characterization of volatiles from cultured dairy spreads during storage by dynamic headspace GC/MS

    DEFF Research Database (Denmark)

    Lund, Pia; Hølmer, Gunhild Kofoed

    2001-01-01

    /MS method using Tenax traps the dairy spreads were analyzed for volatile aromatic compounds. 61 components were identified and their relative content was followed during the storage period. Among these were four alcohols, 17 aldehydes, four esters, ten alkanes, 11 ketones and six lactones. A general...

  10. Thermo-dynamic analysis and simulation of a combined air and hydro energy storage (CAHES) system

    International Nuclear Information System (INIS)

    Bi, Xianyun; Liu, Pei; Li, Zheng

    2016-01-01

    Large-scale energy storage is essential for the stability of a grid, especially for those with large proportion of intermittent renewable energy sources. The efficiency of a conventional compressed air energy storage (CAES) technology is limited by compression heat loss and changing working conditions. In this manuscript, a combined air and hydro energy storage (CAHES) system is proposed, which realizes a higher exergy efficiency compared with conventional CAES systems by reducing compression heat losses and addressing issues of changing working conditions through thermal compensation from solar radiation. The configuration and two operating modes of the proposed CAHES system are firstly introduced, followed by theoretical analysis and numerical simulation under different operating modes to analyze system performances. Impacts of external and internal factors on the system performances are analyzed. The practical feasibility of the system is also investigated. Results show that the exergy efficiency of the system reaches approximately 50%, whilst the charging electricity ratio reaches over 80%. - Highlights: • A combined air and hydro energy storage system is proposed. • High exergy efficiency is achieved and consumption of fossil fuel is eliminated. • The system performance is affected by compression ratio and solar radiation.

  11. Friction and diffusion dynamics of adsorbates at surfaces

    NARCIS (Netherlands)

    Fusco, C.

    2005-01-01

    A theoretical study of the motion of adsorbates (e. g. atoms, molecules or clusters) on solid surfaces is presented, with a focus on surface diffusion and atomic-scale friction. These two phenomena are inextricably linked, because when an atomic or molecular adsorbate diffuses, or is pulled, it

  12. Dynamics of wetting on smooth and rough surfaces.

    NARCIS (Netherlands)

    Cazabat, A.M.; Cohen Stuart, M.A.

    1987-01-01

    The rate of spreading of non-volatile liquids on smooth and on rough surfaces was investigated. The radius of the wetted spot was found to agree with recently proposed scaling laws (t 1/10 for capillarity driven andt 1/8 for gravity driven spreading) when the surface was smooth. However, the

  13. Study of structural, surface and hydrogen storage properties of boric acid mediated metal (sodium)-organic frameworks

    Science.gov (United States)

    Ozer, Demet; Köse, Dursun A.; Sahin, Onur; Oztas, Nursen A.

    2018-04-01

    Three boric acid mediated metal organic frameworks were synthesized by solution method with using succinic acid, fumaric acid and acetylene dicarboxylic acid as a ligand source and sodium as a metal source. The complexes were characterized by FT-IR, powder XRD, elemental analyses and single crystal measurements. The complexes with the formula, C4H18B2Na2O14, C4H16B2Na2O14 and C4H14B2Na2O14 were successfully obtained. BET surface area of complexes were calculated and found as 13.474 m2/g for catena-(tetrakis(μ2-hydroxo)-(μ2-trihydrogen borate)-(μ2-succinato)-di-sodium boric acid solvate), 1.692 m2/g for catena-(tetrakis(μ2-hydroxo)-(μ2-trihydrogen borate)-(μ2-fumarato)-di-sodium boric acid solvate) and 5.600 m2/g for catena-(tetrakis(μ2-hydroxo)-(μ2-trihydrogen borate)-(μ2-acetylenedicarboxylato)-di-sodium boric acid solvate). Hydrogen storage capacities of the complexes were also studied at 77 K 1 bar pressure and found as 0.108%, 0.033%, 0.021% by mass. When different ligands were used, the pore volume, pore width and surface area of the obtained complexes were changed. As a consequence, hydrogen storage capacities also changed.

  14. Coupling surface and mantle dynamics: A novel experimental approach

    Science.gov (United States)

    Kiraly, Agnes; Faccenna, Claudio; Funiciello, Francesca; Sembroni, Andrea

    2015-05-01

    Recent modeling shows that surface processes, such as erosion and deposition, may drive the deformation of the Earth's surface, interfering with deeper crustal and mantle signals. To investigate the coupling between the surface and deep process, we designed a three-dimensional laboratory apparatus, to analyze the role of erosion and sedimentation, triggered by deep mantle instability. The setup is constituted and scaled down to natural gravity field using a thin viscous sheet model, with mantle and lithosphere simulated by Newtonian viscous glucose syrup and silicon putty, respectively. The surface process is simulated assuming a simple erosion law producing the downhill flow of a thin viscous material away from high topography. The deep mantle upwelling is triggered by the rise of a buoyant sphere. The results of these models along with the parametric analysis show how surface processes influence uplift velocity and topography signals.

  15. Risk-constrained dynamic self-scheduling of a pumped-storage plant in the energy and ancillary service markets

    International Nuclear Information System (INIS)

    Kazempour, S. Jalal; Moghaddam, M. Parsa; Haghifam, M.R.; Yousefi, G.R.

    2009-01-01

    This work addresses a new framework for self-scheduling of an individual price-taker pumped-storage plant in a day-ahead (DA) market. The goal is achieving the best trade-off between the expected profit and the risks when the plant participates in DA energy, spinning reserve and regulation markets. In this paper, a set of uncertainties including price forecasting errors and also the uncertainty of power delivery requests in the ancillary service markets are contemplated. Considering these uncertainties, a new approach is proposed which is called dynamic self-scheduling (DSS). This risk-constrained dynamic self-scheduling problem is therefore formulated and solved as a mixed integer programming (MIP) problem. Numerical results for a case study are discussed. (author)

  16. Dynamics of Phenanthrenequinone on Carbon Nano-Onion Surfaces Probed by Quasielastic Neutron Scattering

    International Nuclear Information System (INIS)

    Mamontov, Eugene; Brown, Gilbert M.; Overbury, Steven H.; Mavila Chathoth, Suresh

    2012-01-01

    We used quasielastic neutron scattering (QENS) to study the dynamics of phenanthrenequinone (PQ) on the surface of onion-like carbon (OLC), or so called carbon onions, as a function of surface coverage and temperature. For both the high- and low-coverage samples, we observed two diffusion processes; a faster process and nearly an order of magnitude slower process. On the high-coverage surface, the slow diffusion process is of long-range translational character, whereas the fast diffusion process is spatially localized on the length scale of ∼ 4.7. On the low-coverage surface, both diffusion processes are spatially localized; on the same length scale of ∼ 4.7 for the fast diffusion and a somewhat larger length scale for the slow diffusion. Arrhenius temperature dependence is observed except for the long-range diffusion on the high-coverage surface. We attribute the fast diffusion process to the generic localized in-cage dynamics of PQ molecules, and the slow diffusion process to the long-range translational dynamics of PQ molecules, which, depending on the coverage, may be either spatially restricted, or long-range. On the low-coverage surface, uniform surface coverage is not attained, and the PQ molecules experience the effect of spatial constraints on their long-range translational dynamics. Unexpectedly, the dynamics of PQ molecules on OLC as a function of temperature and surface coverage bears qualitative resemblance to the dynamics of water molecules on oxide surfaces, including practically temperature-independent residence times for the low-coverage surface. The dynamics features that we observed may be universal across different classes of surface adsorbates.

  17. Dynamics of transportan in bicelles is surface charge dependent

    Energy Technology Data Exchange (ETDEWEB)

    Barany-Wallje, Elsa; Andersson, August; Graeslund, Astrid; Maeler, Lena [Stockholm University, Department of Biochemistry and Biophysics, Arrhenius Laboratories (Sweden)], E-mail: lena.maler@dbb.su.se

    2006-06-15

    In this study we investigated the dynamic behavior of the chimeric cell-penetrating peptide transportan in membrane-like environments using NMR. Backbone amide {sup 15}N spin relaxation was used to investigate the dynamics in two bicelles: neutral DMPC bicelles and partly negatively charged DMPG-containing bicelles. The structure of the peptide as judged from CD and chemical shifts is similar in the two cases. Both the overall motion as well as the local dynamics is, however, different in the two types of bicelles. The overall dynamics of the peptide is significantly slower in the partly negatively charged bicelle environment, as evidenced by longer global correlation times for all measured sites. The local motion, as judged from generalized order parameters, is for all sites in the peptide more restricted when bound to negatively charged bicelles than when bound to neutral bicelles (increase in S{sup 2} is on average 0.11 {+-} 0.07). The slower dynamics of transportan in charged membrane model systems cause significant line broadening in the proton NMR spectrum, which in certain cases limits the observation of {sup 1}H signals for transportan when bound to the membrane. The effect of transportan on DMPC and DHPC motion in zwitterionic bicelles was also investigated, and the motion of both components in the bicelle was found to be affected.

  18. Dynamics of transportan in bicelles is surface charge dependent

    International Nuclear Information System (INIS)

    Barany-Wallje, Elsa; Andersson, August; Graeslund, Astrid; Maeler, Lena

    2006-01-01

    In this study we investigated the dynamic behavior of the chimeric cell-penetrating peptide transportan in membrane-like environments using NMR. Backbone amide 15 N spin relaxation was used to investigate the dynamics in two bicelles: neutral DMPC bicelles and partly negatively charged DMPG-containing bicelles. The structure of the peptide as judged from CD and chemical shifts is similar in the two cases. Both the overall motion as well as the local dynamics is, however, different in the two types of bicelles. The overall dynamics of the peptide is significantly slower in the partly negatively charged bicelle environment, as evidenced by longer global correlation times for all measured sites. The local motion, as judged from generalized order parameters, is for all sites in the peptide more restricted when bound to negatively charged bicelles than when bound to neutral bicelles (increase in S 2 is on average 0.11 ± 0.07). The slower dynamics of transportan in charged membrane model systems cause significant line broadening in the proton NMR spectrum, which in certain cases limits the observation of 1 H signals for transportan when bound to the membrane. The effect of transportan on DMPC and DHPC motion in zwitterionic bicelles was also investigated, and the motion of both components in the bicelle was found to be affected

  19. Sensitivity of CO2 storage performance to varying rates and dynamic injectivity in the Bunter Sandstone, UK

    Science.gov (United States)

    Kolster, C.; Mac Dowell, N.; Krevor, S. C.; Agada, S.

    2016-12-01

    Carbon capture and storage (CCS) is needed for meeting legally binding greenhouse gas emissions targets in the UK (ECCC 2016). Energy systems models have been key to identifying the importance of CCS but they tend to impose few constraints on the availability and use of geologic CO2 storage reservoirs. Our aim is to develop simple models that use dynamic representations of limits on CO2 storage resources. This will allow for a first order representation of the storage reservoir for use in systems models with CCS. We use the ECLIPSE reservoir simulator and a model of the Southern North Sea Bunter Sandstone saline aquifer. We analyse reservoir performance sensitivities to scenarios of varying CO2 injection demand for a future UK low carbon energy market. With 12 injection sites, we compare the impact of injecting at a constant 2MtCO2/year per site and varying this rate by a factor of 1.8 and 0.2 cyclically every 5 and 2.5 years over 50 years of injection. The results show a maximum difference in average reservoir pressure of 3% amongst each case and a similar variation in plume migration extent. This suggests that simplified models can maintain accuracy by using average rates of injection over similar time periods. Meanwhile, by initiating injection at rates limited by pressurization at the wellhead we find that injectivity steadily increases. As a result, dynamic capacity increases. We find that instead of injecting into sites on a need basis, we can strategically inject the CO2 into 6 of the deepest sites increasing injectivity for the first 15 years by 13%. Our results show injectivity as highly dependent on reservoir heterogeneity near the injection site. Injecting 1MTCO2/year into a shallow, low permeability and porosity site instead of into a deep injection site with high permeability and porosity reduces injectivity in the first 5 years by 52%. ECCC. 2016. Future of Carbon Capture and Storage in the UK. UK Parliament House of Commons, Energy and Climate Change

  20. A Dynamic Programming Model for Optimizing Frequency of Time-Lapse Seismic Monitoring in Geological CO2 Storage

    Science.gov (United States)

    Bhattacharjya, D.; Mukerji, T.; Mascarenhas, O.; Weyant, J.

    2005-12-01

    Designing a cost-effective and reliable monitoring program is crucial to the success of any geological CO2 storage project. Effective design entails determining both, the optimal measurement modality, as well as the frequency of monitoring the site. Time-lapse seismic provides the best spatial coverage and resolution for reservoir monitoring. Initial results from Sleipner (Norway) have demonstrated effective monitoring of CO2 plume movement. However, time-lapse seismic is an expensive monitoring technique especially over the long term life of a storage project and should be used judiciously. We present a mathematical model based on dynamic programming that can be used to estimate site-specific optimal frequency of time-lapse surveys. The dynamics of the CO2 sequestration process are simplified and modeled as a four state Markov process with transition probabilities. The states are M: injected CO2 safely migrating within the target zone; L: leakage from the target zone to the adjacent geosphere; R: safe migration after recovery from leakage state; and S: seepage from geosphere to the biosphere. The states are observed only when a monitoring survey is performed. We assume that the system may go to state S only from state L. We also assume that once observed to be in state L, remedial measures are always taken to bring it back to state R. Remediation benefits are captured by calculating the expected penalty if CO2 seeped into the biosphere. There is a trade-off between the conflicting objectives of minimum discounted costs of performing the next time-lapse survey and minimum risk of seepage and its associated costly consequences. A survey performed earlier would spot the leakage earlier. Remediation methods would have been utilized earlier, resulting in savings in costs attributed to excessive seepage. On the other hand, there are also costs for the survey and remedial measures. The problem is solved numerically using Bellman's optimality principal of dynamic

  1. 30 CFR 57.4130 - Surface electric substations and liquid storage facilities.

    Science.gov (United States)

    2010-07-01

    ... LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control Prohibitions/precautions/housekeeping § 57.4130 Surface electric...

  2. Live Cell Imaging During Germination Reveals Dynamic Tubular Structures Derived from Protein Storage Vacuoles of Barley Aleurone Cells

    Directory of Open Access Journals (Sweden)

    Verena Ibl

    2014-09-01

    Full Text Available The germination of cereal seeds is a rapid developmental process in which the endomembrane system undergoes a series of dynamic morphological changes to mobilize storage compounds. The changing ultrastructure of protein storage vacuoles (PSVs in the cells of the aleurone layer has been investigated in the past, but generally this involved inferences drawn from static pictures representing different developmental stages. We used live cell imaging in transgenic barley plants expressing a TIP3-GFP fusion protein as a fluorescent PSV marker to follow in real time the spatially and temporally regulated remodeling and reshaping of PSVs during germination. During late-stage germination, we observed thin, tubular structures extending from PSVs in an actin-dependent manner. No extensions were detected following the disruption of actin microfilaments, while microtubules did not appear to be involved in the process. The previously-undetected tubular PSV structures were characterized by complex movements, fusion events and a dynamic morphology. Their function during germination remains unknown, but might be related to the transport of solutes and metabolites.

  3. Analysis of stationary fuel cell dynamic ramping capabilities and ultra capacitor energy storage using high resolution demand data

    Science.gov (United States)

    Meacham, James R.; Jabbari, Faryar; Brouwer, Jacob; Mauzey, Josh L.; Samuelsen, G. Scott

    Current high temperature fuel cell (HTFC) systems used for stationary power applications (in the 200-300 kW size range) have very limited dynamic load following capability or are simply base load devices. Considering the economics of existing electric utility rate structures, there is little incentive to increase HTFC ramping capability beyond 1 kWs -1 (0.4% s -1). However, in order to ease concerns about grid instabilities from utility companies and increase market adoption, HTFC systems will have to increase their ramping abilities, and will likely have to incorporate electrical energy storage (EES). Because batteries have low power densities and limited lifetimes in highly cyclic applications, ultra capacitors may be the EES medium of choice. The current analyses show that, because ultra capacitors have a very low energy storage density, their integration with HTFC systems may not be feasible unless the fuel cell has a ramp rate approaching 10 kWs -1 (4% s -1) when using a worst-case design analysis. This requirement for fast dynamic load response characteristics can be reduced to 1 kWs -1 by utilizing high resolution demand data to properly size ultra capacitor systems and through demand management techniques that reduce load volatility.

  4. Fifteen Years (1993–2007 of Surface Freshwater Storage Variability in the Ganges-Brahmaputra River Basin Using Multi-Satellite Observations

    Directory of Open Access Journals (Sweden)

    Edward Salameh

    2017-03-01

    Full Text Available Surface water storage is a key component of the terrestrial hydrological and biogeochemical cycles that also plays a major role in water resources management. In this study, surface water storage (SWS variations are estimated at monthly time-scale over 15 years (1993–2007 using a hypsographic approach based on the combination of topographic information from Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER and Hydrological Modeling and Analysis Platform (HyMAP-based Global Digital Elevation Models (GDEM and the Global Inundation Extent Multi-Satellite (GIEMS product in the Ganges-Brahmaputra basin. The monthly variations of the surface water storage are in good accordance with precipitation from Global Precipitation Climatology Project (GPCP, river discharges at the outlet of the Ganges and the Brahmaputra, and terrestrial water storage (TWS from the Gravity Recovery And Climate Experiment (GRACE, with correlations higher than 0.85. Surface water storage presents a strong seasonal signal (~496 km3 estimated by GIEMS/ASTER and ~378 km3 by GIEMS/HyMAPs, representing ~51% and ~41% respectively of the total water storage signal and it exhibits a large inter-annual variability with strong negative anomalies during the drought-like conditions of 1994 or strong positive anomalies such as in 1998. This new dataset of SWS is a new, highly valuable source of information for hydrological and climate modeling studies of the Ganges-Brahmaputra river basin.

  5. Oscillon dynamics and rogue wave generation in Faraday surface ripples.

    Science.gov (United States)

    Xia, H; Maimbourg, T; Punzmann, H; Shats, M

    2012-09-14

    We report new experimental results which suggest that the generation of extreme wave events in the Faraday surface ripples is related to the increase in the horizontal mobility of oscillating solitons (oscillons). The analysis of the oscillon trajectories in a horizontal plane shows that at higher vertical acceleration, oscillons move chaotically, merge and form enclosed areas on the water surface. The probability of the formation of such craters, which precede large wave events, increases with the increase in horizontal mobility.

  6. THE EFFECT OF STORAGE AT AMBIENT HUMIDITY ON THE BET-SPECIFIC SURFACE-AREA OF TABLETS COMPACTED FROM DIFFERENT MATERIALS

    NARCIS (Netherlands)

    RIEPMA, KA; DEKKER, BG; JAGER, RS; ELBERSE, PA; LERK, CF

    1993-01-01

    Tablets compacted from both water soluble and water insoluble particulate solids showed no change in BET-specific surface area when transferred immediately after ejection from the die in a dry atmosphere. Storage at ambient humidity resulted in an irreversible decrease in surface area, caused by

  7. Surface dynamics and mechanics in liquid crystal polymer coatings

    Science.gov (United States)

    Liu, Danqing; Broer, Dirk J.

    2015-03-01

    Based on liquid crystal networks we developed `smart' coatings with responsive surface topographies. Either by prepatterning or by the formation of self-organized structures they can be switched on and off in a pre-designed manner. Here we provide an overview of our methods to generate coatings that form surface structures upon the actuation by light. The coating oscillates between a flat surface and a surface with pre-designed 3D micro-patterns by modulating a light source. With recent developments in solid state lighting, light is an attractive trigger medium as it can be integrated in a device for local control or can be used remotely for flood or localized exposure. The basic principle of formation of surface topographies is based on the change of molecular organization in ordered liquid crystal polymer networks. The change in order leads to anisotropic dimensional changes with contraction along the director and expansion to the two perpendicular directions and an increase in volume by the formation of free volume. These two effects work in concert to provide local expansion and contraction in the coating steered by the local direction of molecular orientation. The surface deformation, expressed as the height difference between the activated regions and the non-activated regions divided by the initial film thickness, is of the order of 20%. Switching occurs immediately when the light is switched `on' and `off' and takes several tens of seconds.

  8. Dynamic superhydrophobic behavior in scalable random textured polymeric surfaces

    Science.gov (United States)

    Moreira, David; Park, Sung-hoon; Lee, Sangeui; Verma, Neil; Bandaru, Prabhakar R.

    2016-03-01

    Superhydrophobic (SH) surfaces, created from hydrophobic materials with micro- or nano- roughness, trap air pockets in the interstices of the roughness, leading, in fluid flow conditions, to shear-free regions with finite interfacial fluid velocity and reduced resistance to flow. Significant attention has been given to SH conditions on ordered, periodic surfaces. However, in practical terms, random surfaces are more applicable due to their relative ease of fabrication. We investigate SH behavior on a novel durable polymeric rough surface created through a scalable roll-coating process with varying micro-scale roughness through velocity and pressure drop measurements. We introduce a new method to construct the velocity profile over SH surfaces with significant roughness in microchannels. Slip length was measured as a function of differing roughness and interstitial air conditions, with roughness and air fraction parameters obtained through direct visualization. The slip length was matched to scaling laws with good agreement. Roughness at high air fractions led to a reduced pressure drop and higher velocities, demonstrating the effectiveness of the considered surface in terms of reduced resistance to flow. We conclude that the observed air fraction under flow conditions is the primary factor determining the response in fluid flow. Such behavior correlated well with the hydrophobic or superhydrophobic response, indicating significant potential for practical use in enhancing fluid flow efficiency.

  9. Effects of plasma treatment time on surface characteristics of indium-tin-oxide film for resistive switching storage applications

    International Nuclear Information System (INIS)

    Chen, Po-Hsun; Chang, Ting-Chang; Chang, Kuan-Chang; Tsai, Tsung-Ming; Pan, Chih-Hung; Shih, Chih-Cheng; Wu, Cheng-Hsien; Yang, Chih-Cheng; Chen, Wen-Chung; Lin, Jiun-Chiu; Wang, Ming-Hui; Zheng, Hao-Xuan; Chen, Min-Chen; Sze, Simon M.

    2017-01-01

    In this paper, we implement a post-oxidation method to modify surface characteristics of indium tin oxide (ITO) films by using an O_2 inductively coupled plasma (ICP) treatment. Based on field emission-scanning electron microscope (FE-SEM) and atomic force microscope (AFM) analysis, we found that the surface morphologies of the ITO films become slightly flatter after the O_2 plasma treatment. The optical characteristics and X-ray diffraction (XRD) experiments of either pure ITO or O_2 plasma treated ITO films were also verified. Even though the XRD results showed no difference from bulk crystallizations, the oxygen concentrations increased at the film surface after O_2 plasma treatment, according to the XPS inspection results. Moreover, this study investigated the effects of two different plasma treatment times on oxygen concentration in the ITO films. The surface sheet resistance of the plasma treated ITO films became nearly non-conductive when measured with a 4-point probe. Finally, we applied the O_2 plasma treated ITO films as the insulator in resistive random access memory (RRAM) to examine their potential for use in resistive switching storage applications. Stable resistance switching characteristics were obtained by applying the O_2 plasma treatment to the ITO-based RRAM. We also confirmed the relationship between plasma treatment time and RRAM performance. These material analyses and electrical measurements suggest possible advantages in using this plasma treatment technique in device fabrication processes for RRAM applications.

  10. U-tube based near-surface environmental monitoring in the Shenhua carbon dioxide capture and storage (CCS) project.

    Science.gov (United States)

    Li, Qi; Song, Ranran; Shi, Hui; Ma, Jianli; Liu, Xuehao; Li, Xiaochun

    2018-04-01

    The CO 2 injected into deep formations during implementation of carbon dioxide (CO 2 ) capture and storage (CCS) technology may leak and migrate into shallow aquifers or ground surfaces through a variety of pathways over a long period. The leaked CO 2 can threaten shallow environments as well as human health. Therefore, almost all monitoring programs for CCS projects around the world contain near-surface monitoring. This paper presents a U-tube based near-surface monitoring technology focusing on its first application in the Shenhua CCS demonstration project, located in the Ordos Basin, Inner Mongolia, China. First, background information on the site monitoring program of the Shenhua CCS demonstration project was provided. Then, the principle of fluid sampling and the monitoring methods were summarized for the U-tube sampler system, and the monitoring data were analyzed in detail. The U-tube based monitoring results showed that the U-tube sampler system is accurate, flexible, and representative of the subsurface fluid sampling process. The monitoring indicators for the subsurface water and soil gas at the Shenhua CCS site indicate good stratification characteristics. The concentration level of each monitoring indicator decreases with increasing depth. Finally, the significance of this near-surface environmental monitoring technology for CO 2 leakage assessments was preliminarily confirmed at the Shenhua CCS site. The application potential of the U-tube based monitoring technology was also demonstrated during the subsurface environmental monitoring of other CCS projects.

  11. Tailored lithium storage performance of graphene aerogel anodes with controlled surface defects for lithium-ion batteries

    International Nuclear Information System (INIS)

    Shan, Hui; Xiong, Dongbin; Li, Xifei; Sun, Yipeng; Yan, Bo; Li, Dejun; Lawes, Stephen; Cui, Yanhua; Sun, Xueliang

    2016-01-01

    Graphical abstract: - Highlights: • The graphene aerogel (GA) with controllable surface defects was synthesized. • The graphene aerogel anodes showed high specific capacity and excellent cyclability. • Surface defects on the GA significantly function for lithium storage. • This study can extend the application of the graphene anodes for LIBs. - Abstract: Three dimensional self-assembled graphene aerogel (GA) anode materials with some surface defects have been successfully generated through a facile hydrothermal procedure using graphene oxide as precursor. The morphologies and textural properties of as-obtained GA were investigated by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman and other spectroscopy techniques. The surface defects and electrical conductivities of GA can be controlled by adjusting the hydrothermal reaction time. The results indicate that GA with a reaction time of 6 h exhibits extremely high reversible capacity (1430 mAh g"−"1 at the current density of 100 mA g"−"1) and superior rate capability (587 mAh g"−"1 at 800 mA g"−"1) with excellent cycling stability (maintaining a reversible capacity of 960 mAh g"−"1 at 100 mA g"−"1 after 100 cycles). It is demonstrated that the 3D porous network with increased defect density, as well as the considerable electrical conductivity, results in the excellent electrochemical performance of the as-made GA anodes in lithium-ion batteries.

  12. Effects of plasma treatment time on surface characteristics of indium-tin-oxide film for resistive switching storage applications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Po-Hsun [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China); Chang, Ting-Chang, E-mail: tcchang3708@gmail.com [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China); Advanced Optoelectronics Technology Center, National Cheng Kung University, Tainan 701, Taiwan, ROC (China); Chang, Kuan-Chang, E-mail: kcchang@pkusz.edu.cn [Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China); School of Electronic and Computer Engineering, Peking University, Shenzhen 518055 (China); Tsai, Tsung-Ming; Pan, Chih-Hung; Shih, Chih-Cheng; Wu, Cheng-Hsien; Yang, Chih-Cheng; Chen, Wen-Chung; Lin, Jiun-Chiu; Wang, Ming-Hui [Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China); Zheng, Hao-Xuan; Chen, Min-Chen [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC (China); Sze, Simon M. [Department of Electronics Engineering and Institute of Electronics, National Chiao Tung University, Hsinchu 300, Taiwan, ROC (China)

    2017-08-31

    In this paper, we implement a post-oxidation method to modify surface characteristics of indium tin oxide (ITO) films by using an O{sub 2} inductively coupled plasma (ICP) treatment. Based on field emission-scanning electron microscope (FE-SEM) and atomic force microscope (AFM) analysis, we found that the surface morphologies of the ITO films become slightly flatter after the O{sub 2} plasma treatment. The optical characteristics and X-ray diffraction (XRD) experiments of either pure ITO or O{sub 2} plasma treated ITO films were also verified. Even though the XRD results showed no difference from bulk crystallizations, the oxygen concentrations increased at the film surface after O{sub 2} plasma treatment, according to the XPS inspection results. Moreover, this study investigated the effects of two different plasma treatment times on oxygen concentration in the ITO films. The surface sheet resistance of the plasma treated ITO films became nearly non-conductive when measured with a 4-point probe. Finally, we applied the O{sub 2} plasma treated ITO films as the insulator in resistive random access memory (RRAM) to examine their potential for use in resistive switching storage applications. Stable resistance switching characteristics were obtained by applying the O{sub 2} plasma treatment to the ITO-based RRAM. We also confirmed the relationship between plasma treatment time and RRAM performance. These material analyses and electrical measurements suggest possible advantages in using this plasma treatment technique in device fabrication processes for RRAM applications.

  13. A new and unifying approach to spin dynamics and beam polarization in storage rings

    International Nuclear Information System (INIS)

    Heinemann, K.; Ellison, J.A.

    2014-09-01

    With this paper we extend our studies on polarized beams by distilling tools from the theory of principal bundles. Four major theorems are presented, one which ties invariant fields with the notion of normal form, one which allows one to compare different invariant fields, and two that relate the existence of invariant fields to the existence of certain invariant sets and relations between them. We then apply the theory to the dynamics of spin-1/2 and spin-1 particles and their density matrices describing statistically the particle-spin content of bunches. Our approach thus unifies the spin-vector dynamics from the T-BMT equation with the spin-tensor dynamics and other dynamics. This unifying aspect of our approach relates the examples elegantly and uncovers relations between the various underlying dynamical systems in a transparent way.

  14. Evaluation of in-situ thermal energy storage for lunar based solar dynamic systems

    Science.gov (United States)

    Crane, Roger A.

    1991-01-01

    A practical lunar based thermal energy storage system, based on locally available materials, could significantly reduce transportation requirements and associated costs of a continuous, solar derived power system. The concept reported here is based on a unique, in-situ approach to thermal energy storage. The proposed design is examined to assess the problems of start-up and the requirements for attainment of stable operation. The design remains, at this stage, partially conceptional in nature, but certain aspects of the design, bearing directly on feasibility, are examined in some detail. Specifically included is an engineering evaluation of the projected thermal performance of this system. Both steady state and start-up power requirements are evaluated and the associated thermal losses are evaluated as a basis for establishing potential system performance.

  15. Dynamic modeling of а heating system using geothermal energy and storage tank

    Directory of Open Access Journals (Sweden)

    Milanović Predrag D.

    2012-01-01

    Full Text Available This paper analyzes a greenhouse heating system using geothermal energy and storage tank and the possibility of utilization of insufficient amount of heat from geothermal sources during the periods with low outside air temperatures. Crucial for these analyses is modelling of the necessary yearly energy requirements for greenhouse heating. The results of these analyses enable calculation of an appropriate storage tank capacity so that the energy efficiency of greenhouse heating system with geothermal energy could be significantly improved. [Acknowledgement. This work was supported by Ministry of Science and Technology Development of the Republic of Serbia through the National Energy Efficiency Program (Grant 18234 A. The authors are thankful to the stuff and management of the Company “Farmakom MB PIK 7. juli - Debrc” for their assistance during the realization of this project.

  16. INTRODUCTION: Surface Dynamics, Phonons, Adsorbate Vibrations and Diffusion

    Science.gov (United States)

    Bruch, L. W.

    2004-07-01

    understanding of the underlying factors determining the optical quality of GaInNAs, such as composition, growth and annealing conditions. We are still far from establishing an understanding of the band structure and its dependence on composition. Fundamental electronic interactions such as electron-electron and electron-phonon scattering, dependence of effective mass on composition, strain and orientation, quantum confinement effects, effects of localized nitrogen states on high field transport and on galvanometric properties, and mechanisms for light emission in these materials, are yet to be fully understood. Nature and formation mechanisms of grown-in and processing-induced defects that are important for material quality and device performance are still unknown. Such knowledge is required in order to design strategies to efficiently control and eliminate harmful defects. For many potential applications (such as solar cells, HBTs) it is essential to get more information on the transport properties of dilute nitride materials. The mobility of minority carriers is known to be low in GaInNAs and related material. The experimental values are far from reaching the theoretical ones, due to defects and impurities introduced in the material during the growth. The role of the material inhomogeneities on the lateral carrier transport also needs further investigation. From the device's point of view most attention to date has been focused on the GaInNAs/GaAs system, mainly because of its potential for optoelectronic devices covering the 1.3-1.55 µm data and telecommunications wavelength bands. As is now widely appreciated, these GaAs-compatible structures allow monolithic integration of AlGaAs-based distributed Bragg reflector mirrors (DBRs) for vertical cavity surface-emitting lasers with low temperature sensitivity and compatibility with AlOx-based confinement techniques. In terms of conventional edge-emitting lasers (EELs), the next step is to extend the wavelength range for cw room

  17. Stochastic dynamic stiffness of surface footing for offshore wind turbines

    DEFF Research Database (Denmark)

    Vahdatirad, Mohammadjavad; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    2014-01-01

    Highlights •This study concerns the stochastic dynamic stiffness of foundations for large offshore wind turbines. •A simple model of wind turbine structure with equivalent coupled springs at the base is utilized. •The level of uncertainties is quantified through a sensitivity analysis. •Estimation...

  18. Dynamical models for sand ripples beneath surface waves

    DEFF Research Database (Denmark)

    Andersen, Ken Haste; Chabanol, M.-L.; v. Hecke, M.

    2001-01-01

    We introduce order parameter models for describing the dynamics of sand ripple patterns under oscillatory flow. A crucial ingredient of these models is the mass transport between adjacent ripples, which we obtain from detailed numerical simulations for a range of ripple sizes. Using this mass tra...

  19. Low-temperature aluminum reduction of graphene oxide, electrical properties, surface wettability, and energy storage applications.

    Science.gov (United States)

    Wan, Dongyun; Yang, Chongyin; Lin, Tianquan; Tang, Yufeng; Zhou, Mi; Zhong, Yajuan; Huang, Fuqiang; Lin, Jianhua

    2012-10-23

    Low-temperature aluminum (Al) reduction is first introduced to reduce graphene oxide (GO) at 100-200 °C in a two-zone furnace. The melted Al metal exhibits an excellent deoxygen ability to produce well-crystallized reduced graphene oxide (RGO) papers with a low O/C ratio of 0.058 (Al-RGO), compared with 0.201 in the thermally reduced one (T-RGO). The Al-RGO papers possess outstanding mechanical flexibility and extremely high electrical conductivities (sheet resistance R(s) ~ 1.75 Ω/sq), compared with 20.12 Ω/sq of T-RGO. More interestingly, very nice hydrophobic nature (90.5°) was observed, significantly superior to the reported chemically or thermally reduced papers. These enhanced properties are attributed to the low oxygen content in the RGO papers. During the aluminum reduction, highly active H atoms from H(2)O reacted with melted Al promise an efficient oxygen removal. This method was also applicable to reduce graphene oxide foams, which were used in the GO/SA (stearic acid) composite as a highly thermally conductive reservoir to hold the phase change material for thermal energy storage. The Al-reduced RGO/SnS(2) composites were further used in an anode material of lithium ion batteries possessing a higher specific capacity. Overall, low-temperature Al reduction is an effective method to prepare highly conductive RGO papers and related composites for flexible energy conversion and storage device applications.

  20. The role of reservoir storage in large-scale surface water availability analysis for Europe

    Science.gov (United States)

    Garrote, L. M.; Granados, A.; Martin-Carrasco, F.; Iglesias, A.

    2017-12-01

    A regional assessment of current and future water availability in Europe is presented in this study. The assessment was made using the Water Availability and Adaptation Policy Analysis (WAAPA) model. The model was built on the river network derived from the Hydro1K digital elevation maps, including all major river basins of Europe. Reservoir storage volume was taken from the World Register of Dams of ICOLD, including all dams with storage capacity over 5 hm3. Potential Water Availability is defined as the maximum amount of water that could be supplied at a certain point of the river network to satisfy a regular demand under pre-specified reliability requirements. Water availability is the combined result of hydrological processes, which determine streamflow in natural conditions, and human intervention, which determines the available hydraulic infrastructure to manage water and establishes water supply conditions through operating rules. The WAAPA algorithm estimates the maximum demand that can be supplied at every node of the river network accounting for the regulation capacity of reservoirs under different management scenarios. The model was run for a set of hydrologic scenarios taken from the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP), where the PCRGLOBWB hydrological model was forced with results from five global climate models. Model results allow the estimation of potential water stress by comparing water availability to projections of water abstractions along the river network under different management alternatives. The set of sensitivity analyses performed showed the effect of policy alternatives on water availability and highlighted the large uncertainties linked to hydrological and anthropological processes.

  1. Dynamic changes in proteins during apple (Malus x domestica) fruit ripening and storage

    OpenAIRE

    Shi, Yun; Jiang, Li; Zhang, Li; Kang, Ruoyi; Yu, Zhifang

    2014-01-01

    A proteomic study, using two-dimensional polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight/time-of-flight, was conducted in apple fruit (cv. ‘Golden Delicious’) starting at 10 days prior to harvest through 50 days in storage. Total protein was extracted using a phenol/sodium dodecyl sulfate protocol. More than 400 protein spots were detected in each gel and 55 differentially expressed proteins (p

  2. Evaluation of Dynamic Reversible Chemical Energy Storage with High Temperature Electrolysis

    OpenAIRE

    McVay, Derek Joseph

    2017-01-01

    Renewable power generation is intermittent and non-dispatchable, but is steadily increasing in penetration due to lower costs associated with installation and demand for clean power generation. Without significant energy storage available to a grid with high renewable penetration, a mismatch between the load and the power available can. Furthermore, advanced high temperature nuclear reactors offer clean power generation, but only at a baseload operation scenario due to the significant thermal...

  3. Redox potential dynamics in a grassed swale used for storage and treatment

    Science.gov (United States)

    Vorenhout, Michel; Boogaard, Floris Cornelis

    2016-04-01

    Treatment wetlands are used to remove pollutants from water. Most swales are designed to infiltrate stormwater into the subsurface. A combination of both functions can help to enhance water quality and reduce flooding risks in urban areas. The chemical forms and possible removal of pollutants such as nitrate and heavy metals in wetlands are highly dependent on the redox conditions. The redox conditions are expected to be highly dynamic and dependent on water levels and flow. We studied the correlation between these factors in an urban grassed swale system, and show that more factors play a role in these systems than water levels alone. The study system is located in the World Heritage site "Bryggen" in the city of Bergen, Norway. It consists of a series of SUDS, a socalled treatment train. The system is fed by storm water, which is at first stored in a rain garden then led to grassed swales. Water infiltrates into the subsurface in the swales. The reason for implementation of the system at this site is the protection of the highly organic archaeological layers at the site, which requires reduced conditions. Swales 1 and 2 were equipped with pressure loggers and multi-level redox and temperature probes (-2, -5, -10 and -20cm from surface). Redox and temperature probes were connected to a HYPNOS system. Measurements were taken for more than 1 year at 15 minute interval. A weather station supplemented the dataset with precipitation measurements. The redox potential in the swales show a strong correlation with water level. The regularly flooded swale 2 shows frequent anoxic events (Eh < 200mV) where as swale 1 shows oxic conditions (Eh = 650mV) throughout the same measurement period. Swale 1 has fewer flooding events than Swale 2 and a more coarse soil with less organic matter than swale 2. These redox results are as expected given the local conditions, and show that redox conditions are localised phenomena that depend on local soil conditions. Analysis of the redox

  4. Dynamic links between theta executive functions and alpha storage buffers in auditory and visual working memory.

    Science.gov (United States)

    Kawasaki, Masahiro; Kitajo, Keiichi; Yamaguchi, Yoko

    2010-05-01

    Working memory (WM) tasks require not only distinct functions such as a storage buffer and central executive functions, but also coordination among these functions. Neuroimaging studies have revealed the contributions of different brain regions to different functional roles in WM tasks; however, little is known about the neural mechanism governing their coordination. Electroencephalographic (EEG) rhythms, especially theta and alpha, are known to appear over distributed brain regions during WM tasks, but the rhythms associated with task-relevant regional coupling have not been obtained thus far. In this study, we conducted time-frequency analyses for EEG data in WM tasks that include manipulation periods and memory storage buffer periods. We used both auditory WM tasks and visual WM tasks. The results successfully demonstrated function-specific EEG activities. The frontal theta amplitudes increased during the manipulation periods of both tasks. The alpha amplitudes increased during not only the manipulation but also the maintenance periods in the temporal area for the auditory WM and the parietal area for the visual WM. The phase synchronization analyses indicated that, under the relevant task conditions, the temporal and parietal regions show enhanced phase synchronization in the theta bands with the frontal region, whereas phase synchronization between theta and alpha is significantly enhanced only within the individual areas. Our results suggest that WM task-relevant brain regions are coordinated by distant theta synchronization for central executive functions, by local alpha synchronization for the memory storage buffer, and by theta-alpha coupling for inter-functional integration.

  5. Fuel-assembly behavior under dynamic impact loads due to dry-storage cask mishandling

    International Nuclear Information System (INIS)

    1991-07-01

    Continued operation of nuclear power plants is contingent on the ability to provide adequate storage of spent fuel. Until recently, utilities have been able to maintain interim in-pool spent fuel storage. However, many facilities have reached their capacity and are now faced with shipping their spent fuel in dry casks to alternate storage facilities. The objective of this report is to provide estimates of the structural integrity of irradiated LWR fuel rods subjected to impact loads resulting from postulated cask handling accidents. This is accomplished in five stages: (1) Material properties for irradiated fuel are compiled for use in the structural analyses. (2) Results from parametric analyses of representative assembly designs are used to determine the most limiting case for end and side drop postulated handling accidents. (3) Detailed structural analysis results are presented for these critical designs. The detailed analyses include the coupling of assembly interaction with the cask and cask internals. (4) Criteria for both ultimate stress and brittle fracture failure modes of fuel rod cladding are established. (5) Safe cask handling drop height limits are computed based on items 2 through 4 above. 44 figs., 18 tabs

  6. Quantum Nuclear Extension of Electron Nuclear Dynamics on Folded Effective-Potential Surfaces

    DEFF Research Database (Denmark)

    Hall, B.; Deumens, E.; Ohrn, Y.

    2014-01-01

    A perennial problem in quantum scattering calculations is accurate theoretical treatment of low energy collisions. We propose a method of extracting a folded, nonadiabatic, effective potential energy surface from electron nuclear dynamics (END) trajectories; we then perform nuclear wave packet...

  7. Molecular dynamics simulation of uranium compound adsorption on solid surface

    International Nuclear Information System (INIS)

    Omori, Yuki; Takizawa, Yuji; Okamoto, Tsuyoshi

    2010-01-01

    Particles mixed in the UF6 gas have the property of accumulating on the inside of piping or units. This type of accumulation will cause material unaccounted for (MUF) in the UF6 gas processing facilities. Development of a calculation model for estimating the accumulation rate of uranium compounds has been expected. And predicting possible part of the units where uranium compounds adsorb will contribute to design an effective detection system. The purpose of this study is to take the basic knowledge of the particle's adsorption mechanism from the microscopic point of view. In simulation analysis, UF5 model particle is produced, then two types of solid surfaces are prepared; one is a solid surface at rest and the other is a moving solid surface. The result obtained by the code 'PABS' showed that when the solid surface moves at a lower velocity, the particle's adsorption process dominates over the particle's breakup one. Besides the velocity of the solid surface, other principal factors affecting an adsorption ratio were also discussed. (author)

  8. Nonlinear friction dynamics on polymer surface under accelerated movement

    Directory of Open Access Journals (Sweden)

    Yuuki Aita

    2017-04-01

    Full Text Available Nonlinear phenomena on the soft material surface are one of the most exciting topics of chemical physics. However, only a few reports exist on the friction phenomena under accelerated movement, because friction between two solid surfaces is considered a linear phenomenon in many cases. We aim to investigate how nonlinear accelerated motion affects friction on solid surfaces. In the present study, we evaluate the frictional forces between two polytetrafluoroethylene (PTFE resins using an advanced friction evaluation system. On PTFE surfaces, the normalized delay time δ, which is the time lag in the response of the friction force to the accelerated movement, is observed in the pre-sliding friction process. Under high-velocity conditions, kinetic friction increases with velocity. Based on these experimental results, we propose a two-phase nonlinear model including a pre-sliding process (from the beginning of sliding of a contact probe to the establishment of static friction and a kinetic friction process. The present model consists of several factors including velocity, acceleration, stiffness, viscosity, and vertical force. The findings reflecting the viscoelastic properties of soft material is useful for various fields such as in the fabrication of clothes, cosmetics, automotive materials, and virtual reality systems as well as for understanding friction phenomena on soft material surfaces.

  9. Surface modification of a proton exchange membrane and hydrogen storage in a metal hydride for fuel cells

    Science.gov (United States)

    Andrews, Lisa

    Interest in fuel cell technology is rising as a result of the need for more affordable and available fuel sources. Proton exchange membrane fuel cells involve the catalysis of a fuel to release protons and electrons. It requires the use of a polymer electrolyte membrane to transfer protons through the cell, while the electrons pass through an external circuit, producing electricity. The surface modification of the polymer, NafionRTM, commonly researched as a proton exchange membrane, may improve efficiency of a fuel cell. Surface modification can change the chemistry of the surface of a polymer while maintaining bulk properties. Plasma modification techniques such as microwave discharge of an argon and oxygen gas mixture as well as vacuum-ultraviolet (VUV) photolysis may cause favorable chemical and physical changes on the surface of Nafion for improved fuel cell function. A possible increase in hydrophilicity as a result of microwave discharge experiments may increase proton conductivity. Grafting of acrylic acid from the surface of modified Nafion may decrease the permeation of methanol in a direct methanol fuel cell, a process which can decrease efficiency. Modification of the surface of Nafion samples were carried out using: 1) An indirect Ar/O2 gas mixture plasma investigating the reaction of oxygen radicals with the surface, 2) A direct Ar/O2 gas mixture plasma investigating the reaction of oxygen radicals and VUV radiation with the surface and, 3) VUV photolysis investigating exclusively the interaction of VUV radiation with the surface and any possible oxidation upon exposure to air. Acrylic acid was grafted from the VUV photolysed Nafion samples. All treated surfaces were analyzed using X-ray photoelectron spectroscopy (XPS). Fourier transform infrared spectroscopy (FTIR) was used to analyze the grafted Nafion samples. Scanning electron microscopy (SEM) and contact angle measurements were used to analyze experiments 2 and 3. Using hydrogen as fuel is a

  10. Development of a dynamic model for cleaning ultra filtration membranes fouled by surface water

    NARCIS (Netherlands)

    Zondervan, Edwin; Betlem, Ben H.L.; Roffel, Brian

    2007-01-01

    In this paper, a dynamic model for cleaning ultra filtration membranes fouled by surface water is proposed. A model that captures the dynamics well is valuable for the optimization of the cleaning process. The proposed model is based on component balances and contains three parameters that can be

  11. Accelerating solving the dynamic multi-objective nework design problem using response surface methods

    NARCIS (Netherlands)

    Wismans, Luc Johannes Josephus; van Berkum, Eric C.; Bliemer, Michiel C.J.; Viti, F.; Immers, B.; Tampere, C.

    2011-01-01

    Multi objective optimization of externalities of traffic solving a network design problem in which Dynamic Traffic Management measures are used, is time consuming while heuristics are needed and solving the lower level requires solving the dynamic user equilibrium problem. Use of response surface

  12. Dynamical phases of attractive particles sliding on a structured surface

    International Nuclear Information System (INIS)

    Hasnain, J; Jungblut, S; Dellago, C

    2015-01-01

    Inspired by experiments on quartz crystal microbalance setups, we study the mobility of a monolayer of Lennard-Jones particles driven over a hexagonal external potential. We pay special attention to the changes in the dynamical phases that arise when the lattice constant of the external substrate potential and the Lennard-Jones interaction are mismatched. We find that if the average particle separation is such that the particles repel each other, or interact harmonically, the qualitative behavior of the system is akin to that of a monolayer of purely repulsive Yukawa particles. On the other hand, if the particles typically attract each other, the ensuing dynamical states are determined entirely by the relative strength of the Lennard-Jones interaction with respect to that of the external potential. (paper)

  13. Dynamical structure of the turbulent boundary layer on rough surface

    Czech Academy of Sciences Publication Activity Database

    Uruba, Václav; Jonáš, Pavel; Hladík, Ondřej

    2011-01-01

    Roč. 11, č. 1 (2011), s. 603-604 ISSN 1617-7061 R&D Projects: GA ČR GA101/08/1112; GA ČR GAP101/10/1230 Institutional research plan: CEZ:AV0Z20760514 Keywords : turbulent boundary layer * rough wall * hairpin vortex Subject RIV: BK - Fluid Dynamics http://onlinelibrary.wiley.com/doi/10.1002/pamm.201110291/abstract

  14. Greenland meltwater storage in firn limited by near-surface ice formation

    DEFF Research Database (Denmark)

    Machguth, Horst; MacFerrin, Mike; van As, Dirk

    2016-01-01

    above sea level), firn has undergone substantial densification, while at lower elevations, where melt is most abundant, porous firn has lost most of its capability to retain meltwater. Here, the formation of near-surface ice layers renders deep pore space difficult to access, forcing meltwater to enter...

  15. Dynamic optimization and robust explicit model predictive control of hydrogen storage tank

    KAUST Repository

    Panos, C.

    2010-09-01

    We present a general framework for the optimal design and control of a metal-hydride bed under hydrogen desorption operation. The framework features: (i) a detailed two-dimension dynamic process model, (ii) a design and operational dynamic optimization step, and (iii) an explicit/multi-parametric model predictive controller design step. For the controller design, a reduced order approximate model is obtained, based on which nominal and robust multi-parametric controllers are designed. © 2010 Elsevier Ltd.

  16. Dynamic optimization and robust explicit model predictive control of hydrogen storage tank

    KAUST Repository

    Panos, C.; Kouramas, K.I.; Georgiadis, M.C.; Pistikopoulos, E.N.

    2010-01-01

    We present a general framework for the optimal design and control of a metal-hydride bed under hydrogen desorption operation. The framework features: (i) a detailed two-dimension dynamic process model, (ii) a design and operational dynamic optimization step, and (iii) an explicit/multi-parametric model predictive controller design step. For the controller design, a reduced order approximate model is obtained, based on which nominal and robust multi-parametric controllers are designed. © 2010 Elsevier Ltd.

  17. COMPARATIVE DYNAMICS OF PROTEIN DESTRUCTION IN CANNED FOODS IN SAUCE AT DIFFERENT THERMAL TREATMENT REGIMES AND SUBSEQUENT STORAGE

    Directory of Open Access Journals (Sweden)

    V. B. Krylova

    2017-01-01

    Full Text Available In the course of investigations, the structural changes in proteins were established, which were associated with the preliminary treatment of meat ingredients, a pH level of the system and parameters of thermal treatment.The pasteurization regimes allowed retaining a protein nitrogen proportion up to 94% by the end of canned food storage duration. Upon sterilization, the losses in protein nitrogen were two times higher. A negative effect of more acidic sauce on preservation of the protein nitrogen fraction in canned foods was established.An accumulation of the peptide nitrogen fraction in the canned foods in tomato sauce aſter pasteurization was two times more intensive. In the sterilized canned foods, the processes of accumulation of the low molecular weight nitrogenous compounds were more intensive, which suggests a depth of destruction of the protein and peptide nitrogen fraction. It was shown that an accumulation of amino-ammonia nitrogen during canned food storage was on average 12.4% irrespective of the pH value in the used sauces and the type of thermal treatment.A shiſt in the pH value of the canned foods toward the acid side upon pasteurization was noticed. With that, a degree of the shiſt in the canned foods in tomato sauce was 2.5 times higher than the pH value of the canned foods in sour cream sauce. When sterilizing canned foods, another dynamics of the pH values was observed: a pH value declined by 0.39 units in the canned foods in tomato sauce and grew by 0.22 units in the canned foods in sour cream sauce. During storage, the tendency of more intense pH decline was revealed for the canned foods in tomato sauce aſter pasteurization compared to the canned foods aſter sterilization. Another character of the pH value dynamics was found in the canned foods in sour cream sauce: an insignificant increase (by 0.7% of the pH value in the pasteurized canned foods and a significant decrease (by 8.4% in the sterilized canned foods

  18. Surface dynamics and mechanics in liquid crystal polymer coatings

    NARCIS (Netherlands)

    Liu, D.; Broer, D.J.; Chien, L.-C.; Coles, H.J.; Kikuchi, H.; Smalyukh, I.I.

    2015-01-01

    Based on liquid crystal networks we developed 'smart' coatings with responsive surface topographies. Either by prepatterning or by the formation of self-organized structures they can be switched on and off in a pre-designed manner. Here we provide an overview of our methods to generate coatings that

  19. Body surface adaptations to boundary-layer dynamics

    NARCIS (Netherlands)

    Videler, J.J.

    1995-01-01

    Evolutionary processes have adapted nektonic animals to interact efficiently with the water that surrounds them. Not all these adaptations serve the same purpose. This paper concentrates on reduction of drag due to friction in the boundary layer close to the body surface. Mucus, compliant skins,

  20. Dynamic and Impure Perovskite Structured Metal Oxide Surfaces

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Norrman, Kion; Traulsen, Marie Lund

    2017-01-01

    Surfaces of LSF and LSCF perovskite model electrodes were investigated using a variety of analytical methods on flat model electrodes that were prepared as either pellets or as thin films on top of YSZ pellets in other to throw more light on the widely discussed segregation of layers and particles...

  1. Ni-doping effect of Mg(0 0 0 1) surface to use it as a hydrogen storage material

    International Nuclear Information System (INIS)

    Kuklin, Artem V.; Kuzubov, Alexander A.; Krasnov, Pavel O.; Lykhin, Aleksandr O.; Tikhonova, Lyudmila V.

    2014-01-01

    Highlights: • Magnesium surface interaction with nickel at different it location was investigated. • A possibility of nickel migration on magnesium surface was examined. • A possibility of the nickel atoms to aggregate, producing the cluster was investigated. • A step by step diagram of the cluster formation was calculated and constructed. • The final step was the investigation of a hydrogenation process on the Ni cluster. - Abstract: A detailed study of Ni-doped Mg(0 0 0 1) surface performed by PAW method and the gradient corrected density functional GGA-PBE within the framework of generalized Kohn–Sham density functional theory (DFT) is presented in this work. Structural and electronic properties of magnesium surface interaction with nickel for the purpose of such compounds use for creation of hydrogen storage matrixes were investigated here. Choice of the PBE functional was caused by the good accordance of its prediction of the cell parameters with experimental results. It was shown that Ni atoms prefer to substitute for Mg atoms. Using NEB method, the diffusion barrier was calculated, and the most probable reaction path was established. In particular, when the Ni atom dopes the magnesium surface, it can migrate to the bulk and substitute for Mg in subsurface layers. Also a possibility of nickel cluster formation on clean surface of magnesium was examined. The kinetic factors hinder the movement of the nickel atoms to each other and make problematic the formation of clusters. The studies presented here showed that the diffusion barriers of the nickel atom migration from the cluster on the surface to the bulk of magnesium are 1.179 eV and 1.211 eV for the forward and reverse reactions, respectively. Therefore an improvement of the hydrogenation properties of Ni-doped magnesium surface depends on deposition not of the individual atoms, but their clusters. Hydrogenation of Ni cluster doping the magnesium surface was investigated. Initially Kubas

  2. Reaction and Aggregation Dynamics of Cell Surface Receptors

    Science.gov (United States)

    Wang, Michelle Dong

    This dissertation is composed of both theoretical and experimental studies of cell surface receptor reaction and aggregation. Project I studies the reaction rate enhancement due to surface diffusion of a bulk dissolved ligand with its membrane embedded target, using numerical calculations. The results show that the reaction rate enhancement is determined by ligand surface adsorption and desorption kinetic rates, surface and bulk diffusion coefficients, and geometry. In particular, we demonstrate that the ligand surface adsorption and desorption kinetic rates, rather than their ratio (the equilibrium constant), are important in rate enhancement. The second and third projects are studies of acetylcholine receptor clusters on cultured rat myotubes using fluorescence techniques after labeling the receptors with tetramethylrhodamine -alpha-bungarotoxin. The second project studies when and where the clusters form by making time-lapse movies. The movies are made from overlay of the pseudocolored total internal reflection fluorescence (TIRF) images of the cluster, and the schlieren images of the cell cultures. These movies are the first movies made using TIRF, and they clearly show the cluster formation from the myoblast fusion, the first appearance of clusters, and the eventual disappearance of clusters. The third project studies the fine structural features of individual clusters observed under TIRF. The features were characterized with six parameters by developing a novel fluorescence technique: spatial fluorescence autocorrelation. These parameters were then used to study the feature variations with age, and with treatments of drugs (oligomycin and carbachol). The results show little variation with age. However, drug treatment induced significant changes in some parameters. These changes were different for oligomycin and carbachol, which indicates that the two drugs may eliminate clusters through different mechanisms.

  3. Design and dynamic behaviour of a cold storage system combined with a solar powered thermoacoustic refrigerator

    International Nuclear Information System (INIS)

    Perier-Muzet, Maxime; Bedecarrats, Jean-Pierre; Stouffs, Pascal; Castaing-Lasvignottes, Jean

    2014-01-01

    A heat powered thermoacoustic refrigerator consists in a thermoacoustic engine that produces acoustic work utilizing heat, coupled to a thermoacoustic cooler that converts this acoustic energy into cooling effect. These machines have already proved their capability in laboratory or in space refrigeration. Previous studies have also demonstrated the possibility of using concentrated solar energy as thermal energy sources for low power heat driven thermoacoustic refrigerators. As other solar refrigeration systems, even if the cooling demand generally increases with the intensity of the solar radiation, one of the major difficulties is to insure a frigorific power supply when there is no, or low, solar radiation. The aim of this work is to study a kW scale solar thermoacoustic refrigerator capable to reach temperatures of the industrial refrigeration domain. This refrigerator is combined with a latent cold storage in order to guarantee a sufficient cooling capacity to face to refrigeration loads in spite of the production fluctuations. A description of the studied prototype is done and the model developed to describe the transient behaviour of the main components of this machine is introduced. The results obtained with a simulation of one week with real solar radiations are presented and the behaviour and the energetic performances of the entire system are analysed. Finally the impact of the sizing of the cold storage system is discussed. With the best storage design, the system is capable to supply a cooling power of 400 W at a temperature equal or lower than −20 °C with an average Coefficient Of Performance of the solar thermoacoustic refrigerator equal to 21%

  4. Fluid dynamic studies for a simulated Melton Valley Storage Tank slurry

    International Nuclear Information System (INIS)

    Hylton, T.D.; Youngblood, E.L.; Cummins, R.L.

    1994-07-01

    The Melton Valley Storage Tanks (MVSTs), are used for the collection and storage of remote-handled radioactive liquid wastes. These wastes, which were typically acidic when generated, were neutralized with the addition of sodium hydroxide to protect the storage tanks from corrosion, but this caused the transuranic and heavy metals to precipitate. These wastes will eventually need to be removed from the tanks for ultimate disposal. The objective of the research activities discussed in this report is to support the design of a pipeline transport system between the MVSTs and a treatment facility. Since the wastes in the MVSTs are highly radioactive, a surrogate slurry was developed for this study. Rheological properties of the simulated slurry were determined in a test loop in which the slurry was circulated through three pipeline viscometers of different diameters. Pressure drop data at varying flow rates were used to obtain shear stress and shear rate data. The data were analyzed, and the slurry rheological properties were analyzed by the Power Law model and the Bingham plastic model. The plastic viscosity and yield stress data obtained from the rheological tests were used as inputs for a piping design software package, and the pressure drops predicted by the software compared well with the pressure drop data obtained from the test loop. The minimum transport velocity was determine for the slurry by adding known nominal sizes of glass spheres to the slurry. However, it was shown that the surrogate slurry exhibited hindered settling, which may substantially decrease the minimum transport velocity. Therefore, it may be desired to perform additional tests with a surrogate with a lower concentration of suspended solids to determine the minimum transport velocity

  5. Dynamic modeling method of the bolted joint with uneven distribution of joint surface pressure

    Science.gov (United States)

    Li, Shichao; Gao, Hongli; Liu, Qi; Liu, Bokai

    2018-03-01

    The dynamic characteristics of the bolted joints have a significant influence on the dynamic characteristics of the machine tool. Therefore, establishing a reasonable bolted joint dynamics model is helpful to improve the accuracy of machine tool dynamics model. Because the pressure distribution on the joint surface is uneven under the concentrated force of bolts, a dynamic modeling method based on the uneven pressure distribution of the joint surface is presented in this paper to improve the dynamic modeling accuracy of the machine tool. The analytic formulas between the normal, tangential stiffness per unit area and the surface pressure on the joint surface can be deduced based on the Hertz contact theory, and the pressure distribution on the joint surface can be obtained by the finite element software. Futhermore, the normal and tangential stiffness distribution on the joint surface can be obtained by the analytic formula and the pressure distribution on the joint surface, and assigning it into the finite element model of the joint. Qualitatively compared the theoretical mode shapes and the experimental mode shapes, as well as quantitatively compared the theoretical modal frequencies and the experimental modal frequencies. The comparison results show that the relative error between the first four-order theoretical modal frequencies and the first four-order experimental modal frequencies is 0.2% to 4.2%. Besides, the first four-order theoretical mode shapes and the first four-order experimental mode shapes are similar and one-to-one correspondence. Therefore, the validity of the theoretical model is verified. The dynamic modeling method proposed in this paper can provide a theoretical basis for the accurate dynamic modeling of the bolted joint in machine tools.

  6. Application of superconducting magnet energy storage to improve power system dynamic performance

    International Nuclear Information System (INIS)

    Mitani, Y.; Tsuji, K.; Murakami, Y.

    1988-01-01

    The application of Superconducting Magnet Energy Storage (SMES) to the stabilization of a power system with long distance bulk power transmission lines which has the problem of poorly damped power oscillations, is presented. Control schemes for stabilization using SMES which is capable of controlling active and reactive power simultaneously in four quadrant ranges, is proposed. The effective locations and the necessary capacities of SMES for power system stabilizing control are discussed in detail. Results of numerical analysis and experiments in an artificial power transmission system demonstrate the significant effect of the control by SMES on the improvement of power system oscillatory performance

  7. Experimental investigation of the dynamic behavior of a large-scale refrigeration – PCM energy storage system. Validation of a complete model

    International Nuclear Information System (INIS)

    Wu, Jing; Tremeac, Brice; Terrier, Marie-France; Charni, Mehdi; Gagnière, Emilie; Couenne, Françoise; Hamroun, Boussad; Jallut, Christian

    2016-01-01

    In the area of buildings refrigeration, the use of thermal energy storages coupled with heat pumps is a significant way for reducing the operating costs and optimizing the design of equipment. In this paper, a prototype of large-scale refrigeration - PCM (Phase Change Material) energy storage system is described, from which experimental results on transient behavior are obtained. A dynamic model for transient simulation of the coupled system is presented. The fluid flows through the heat exchangers and the storage tank are represented by a cascade of Continuous Stirred Tank Reactors (CSTRs). Switching procedures between different model configurations associated to phase transitions within heat exchangers and PCM storage tank are mathematically performed by matrix operations. The compressor, the expansion valve and the pressure drop across the evaporator are represented by static models based on empirical correlations. A PI controller for the expansion valve opening is integrated in the heat pump model to maintain the superheat at evaporator exit. The model is validated by a complete and detailed comparison between simulation and experimental results. - Highlights: • Experimental investigation of a refrigeration-PCM storage system is presented. • A detailed dynamic model for the coupled system is proposed. • Fluid flows in heat exchangers and PCM storage are represented by a cascade of CSTRs. • Phase transitions events according to time and space within heat exchangers and PCM storage are considered in the model. • Complete comparisons between experimental and simulation results are carried out.

  8. Converting biomass waste into microporous carbon with simultaneously high surface area and carbon purity as advanced electrochemical energy storage materials

    Science.gov (United States)

    Sun, Fei; Wang, Lijie; Peng, Yiting; Gao, Jihui; Pi, Xinxin; Qu, Zhibin; Zhao, Guangbo; Qin, Yukun

    2018-04-01

    Developing carbon materials featuring both high accessible surface area and high structure stability are desirable to boost the performance of constructed electrochemical electrodes and devices. Herein, we report a new type of microporous carbon (MPC) derived from biomass waste based on a simple high-temperature chemical activation procedure. The optimized MPC-900 possesses microporous structure, high surface area, partially graphitic structure, and particularly low impurity content, which are critical features for enhancing carbon-based electrochemical process. The constructed MPC-900 symmetric supercapacitor exhibits high performances in commercial organic electrolyte such as widened voltage window up to 3 V and thereby high energy/power densities (50.95 Wh kg-1 at 0.44 kW kg-1; 25.3 Wh kg-1 at 21.5 kW kg-1). Furthermore, a simple melt infiltration method has been employed to enclose SnO2 nanocrystals onto the carbon matrix of MPC-900 as a high-performance lithium storage material. The obtained SnO2-MPC composite with ultrafine SnO2 nanocrystals delivers high capacities (1115 mAh g-1 at 0.2 A g-1; 402 mAh g-1 at 10 A g-1) and high-rate cycling lifespan of over 2000 cycles. This work not only develops a microporous carbon with high carbon purity and high surface area, but also provides a general platform for combining electrochemically active materials.

  9. Molecular dynamics simulations of water on a hydrophilic silica surface at high air pressures

    DEFF Research Database (Denmark)

    Zambrano, H.A.; Walther, Jens Honore; Jaffe, R.L.

    2014-01-01

    Wepresent a force field forMolecular Dynamics (MD) simulations ofwater and air in contactwith an amorphous silica surface. We calibrate the interactions of each species present in the systemusing dedicated criteria such as the contact angle of a water droplet on a silica surface, and the solubility...

  10. Non-equilibrium dynamics of single polymer adsorption to solid surfaces

    NARCIS (Netherlands)

    Panja, D.; Barkema, G.T.; Kolomeisky, A.B.

    2009-01-01

    The adsorption of polymers to surfaces is crucial for understanding many fundamental processes in nature. Recent experimental studies indicate that the adsorption dynamics is dominated by non-equilibrium effects. We investigate the adsorption of a single polymer of length N to a planar solid surface

  11. On-farm irrigation reservoirs for surface water storage in eastern Arkansas: Trends in construction in response to aquifer depletion

    Science.gov (United States)

    Yaeger, M. A.; Reba, M. L.; Massey, J. H.; Adviento-Borbe, A.

    2017-12-01

    On-farm surface water storage reservoirs have been constructed to address declines in the Mississippi River Valley Alluvial aquifer, the primary source of irrigation for most of the row crops grown in eastern Arkansas. These reservoirs and their associated infrastructure represent significant investments in financial and natural resources, and may cause producers to incur costs associated with foregone crop production and long-term maintenance. Thus, an analysis of reservoir construction trends in the Grand Prairie Critical Groundwater Area (GPCGA) and Cache River Critical Groundwater Area (CRCGA) was conducted to assist future water management decisions. Between 1996 and 2015, on average, 16 and 4 reservoirs were constructed per year, corresponding to cumulative new reservoir surface areas of 161 and 60 ha yr-1, for the GPCGA and the CRCGA, respectively. In terms of reservoir locations relative to aquifer status, after 1996, 84.5% of 309 total reservoirs constructed in the GPCGA and 91.0% of 78 in the CRCGA were located in areas with remaining saturated aquifer thicknesses of 50% or less. The majority of new reservoirs (74% in the GPCGA and 63% in the CRCGA) were constructed on previously productive cropland. The next most common land use, representing 11% and 15% of new reservoirs constructed in the GPCGA and CRCGA, respectively, was the combination of a field edge and a ditch, stream, or other low-lying area. Less than 10% of post-1996 reservoirs were constructed on predominately low-lying land, and the use of such lands decreased in both critical groundwater areas during the past 20 years. These disparities in reservoir construction rates, locations, and prior land uses is likely due to groundwater declines being first observed in the GPCGA as well as the existence of two large-scale river diversion projects under construction in the GPCGA that feature on-farm storage as a means to offset groundwater use.

  12. Effect of surface topography upon micro-impact dynamics

    International Nuclear Information System (INIS)

    Mohammadpour, M; Morris, N J; Leighton, M; Rahnejat, H

    2016-01-01

    Often the effect of interactions at nano-scale determines the tribological performance of load bearing contacts. This is particularly the case for lightly loaded conjunctions where a plethora of short range kinetic interactions occur. It is also true of larger load bearing conjunctions where boundary interactions become dominant. At the diminutive scale of fairly smooth surface topography the cumulative discrete interactions give rise to the dominance of boundary effects rather than the bulk micro-scale phenomena, based on continuum mechanics. The integration of the manifold localized discrete interactions into a continuum is the pre-requisite to the understanding of characteristic boundary effects, which transcend the physical length scales and affect the key observed system attributes. These are energy efficiency and vibration refinement. This paper strives to present such an approach. It is shown that boundary and near boundary interactions can be adequately described by surface topographical measures, as well the thermodynamic conditions. (paper)

  13. Thermal analysis of heat storage canisters for a solar dynamic, space power system

    Science.gov (United States)

    Wichner, R. P.; Solomon, A. D.; Drake, J. B.; Williams, P. T.

    1988-01-01

    A thermal analysis was performed of a thermal energy storage canister of a type suggested for use in a solar receiver for an orbiting Brayton cycle power system. Energy storage for the eclipse portion of the cycle is provided by the latent heat of a eutectic mixture of LiF and CaF2 contained in the canister. The chief motivation for the study is the prediction of vapor void effects on temperature profiles and the identification of possible differences between ground test data and projected behavior in microgravity. The first phase of this study is based on a two-dimensional, cylindrical coordinates model using an interim procedure for describing void behavor in 1-g and microgravity. The thermal analysis includes the effects of solidification front behavior, conduction in liquid/solid salt and canister materials, void growth and shrinkage, radiant heat transfer across the void, and convection in the melt due to Marangoni-induced flow and, in 1-g, flow due to density gradients. A number of significant differences between 1-g and o-g behavior were found. This resulted from differences in void location relative to the maximum heat flux and a significantly smaller effective conductance in 0-g due to the absence of gravity-induced convection.

  14. Exploring Sub-Femtosecond Correlated Dynamics with an Ultra-low Energy Electrostatic Storage Ring

    International Nuclear Information System (INIS)

    Welsch, C.P.; Grieser, M.; Dorn, A.; Moshammer, R.; Ullrich, J.

    2005-01-01

    Whereas the three-body Coulomb problem for single excitation and ionization was claimed to be solved in a mathematically correct way during 1999 until 2004 for electron impact on hydrogen and helium, ion-impact ionization still represents a major challenge for theory. Troubling discrepancies have been observed recently in fully differential cross sections (FDCS) for helium single ionization by fast ion impact and even experimental total cross sections are in striking disagreement with the predictions of all state-of-the-art theories for low-energy antiproton collisions. Therefore, within the future Facility for Low-energy Antiproton and Ion Research (FLAIR), it has been proposed to combine state-of-the-art many-particle imaging methods with a novel electrostatic storage ring for slow antiprotons in order to realize single and multiple ionization cross section measurements for antiprotons colliding with atoms, molecules and clusters. Total, as well as any differential cross sections up to FDCS including ionization-excitation reactions are envisaged to become available, serving as benchmark data for theory. Here, the present status of experiments in comparison with theory is presented and the layout of an Ultra-low energy Storage Ring (USR) with its integrated reaction microscope at FLAIR is described

  15. Dynamic surface-pressure instrumentation for rods in parallel flow

    International Nuclear Information System (INIS)

    Mulcahy, T.M.; Lawrence, W.

    1979-01-01

    Methods employed and experience gained in measuring random fluid boundary layer pressures on the surface of a small diameter cylindrical rod subject to dense, nonhomogeneous, turbulent, parallel flow in a relatively noise-contaminated flow loop are described. Emphasis is placed on identification of instrumentation problems; description of transducer construction, mounting, and waterproofing; and the pretest calibration required to achieve instrumentation capable of reliable data acquisition

  16. Dirac and Weyl fermion dynamics on two-dimensional surface

    International Nuclear Information System (INIS)

    Kavalov, A.R.; Sedrakyan, A.G.; Kostov, I.K.

    1986-01-01

    Fermions on 2-dimensional surface, embedded into a 3-dimensional space are investigated. The determinant of induced Dirac operator for the Dirac and Weyl fermions is calculated. The reparametrization-invariant effective action is determined by conformal anomaly (giving Liouville action) and also by Lorentz anomaly leading to Wess-Zumino term, the structure of which at d=3 is determined by the Hopf topological invariant of the S 3 → S 2 map

  17. Dynamics of radon-222 near below ground surface

    International Nuclear Information System (INIS)

    Fukui, Masami; Katsurayama, Kousuke; Nishimura, Susumu.

    1986-01-01

    The concentrations and variation of 222 Rn were investigated both in unconfined groundwater and in the aerated zone to obtain information as to the behavior of Rn close to ground surface. The Rn concentrations in unconfined groundwater near the surface were depletive by the extent of about 50 % compared with that of lower part in a borehole, then the continuous extraction of groundwater causes pronounced increase of the concentration. The method, which monitors continuously the Rn concentration in such surroundings, was developed, where the unconfined groundwater extracted was injected into another borehole and sprayed gas was measured using an ionization chamber. The read-out values of this system well followed the variation of concentrations caused by the meteorological parameter, especially infiltrating water. The increase of 222 Rn concentration in the aerated zone above the water level was clearly observed following the ascendant of groundwater level caused by the infiltrating water, whereas the change of concentration in soil air just below the ground surface obeyed mainly to the wetness of soil and unconfined groundwater level rather than atmospheric pressure. (author)

  18. Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Xun Yang

    2017-08-01

    Full Text Available In this study, the dynamic melting process of the phase change material (PCM in a vertical cylindrical tube-in-tank thermal energy storage (TES unit was investigated through numerical simulations and experimental measurements. To ensure good heat exchange performance, a concentric helical coil was inserted into the TES unit to pipe the heat transfer fluid (HTF. A numerical model using the computational fluid dynamics (CFD approach was developed based on the enthalpy-porosity method to simulate the unsteady melting process including temperature and liquid fraction variations. Temperature measurements using evenly spaced thermocouples were conducted, and the temperature variation at three locations inside the TES unit was recorded. The effects of the HTF inlet parameters were investigated by parametric studies with different temperatures and flow rate values. Reasonably good agreement was achieved between the numerical prediction and the temperature measurement, which confirmed the numerical simulation accuracy. The numerical results showed the significance of buoyancy effect for the dynamic melting process. The system TES performance was very sensitive to the HTF inlet temperature. By contrast, no apparent influences can be found when changing the HTF flow rates. This study provides a comprehensive solution to investigate the heat exchange process of the TES system using PCM.

  19. Geoelectric Monitoring of geological CO2 storage at Ketzin, Germany (CO2SINK project): Downhole and Surface-Downhole measurements

    Science.gov (United States)

    Kiessling, D.; Schuett, H.; Schoebel, B.; Krueger, K.; Schmidt-Hattenberger, C.; Schilling, F.

    2009-04-01

    Numerical models of the CO2 storage experiment CO2SINK (CO2 Storage by Injection into a Natural Saline Aquifer at Ketzin), where CO2 is injected into a deep saline aquifer at roughly 650 m depth, yield a CO2 saturation of approximately 50% for large parts of the plume. Archie's equation predicts an increase of the resistivity by a factor of approximately 3 to 4 for the reservoir sandstone, and laboratory tests on Ketzin reservoir samples support this prediction. Modeling results show that tracking the CO2 plume may be doable with crosshole resistivity surveys under these conditions. One injection well and two observation wells were drilled in 2007 to a depth of about 800 m and were completed with "smart" casings, arranged L-shaped with distances of 50 m and 100 m. 45 permanent ring-shaped steel electrodes were attached to the electrically insulated casings of the three Ketzin wells at 590 m to 735 m depth with a spacing of about 10 m. It is to our knowledge the deepest permanent vertical electrical resistivity array (VERA) worldwide. The electrodes are connected to the current power supply and data registration units at the surface through custom-made cables. This deep electrode array allows for the registration of electrical resistivity tomography (ERT) data sets at basically any desired repetition rate and at very low cost, without interrupting the injection operations. The installation of all 45 electrodes succeeded. The electrodes are connected to the electrical cable, and the insulated casing stood undamaged. Even after 2-odd years under underground conditions only 6 electrodes are in a critical state now, caused by corrosion effects. In the framework of the COSMOS project (CO2-Storage, Monitoring and Safety Technology), supported by the German "Geotechnologien" program, the geoelectric monitoring has been performed. The 3D crosshole time-laps measurements are taken using dipole-dipole configurations. The data was inverted using AGI EarthImager 3D to obtain 3D

  20. Cooperative storage of shared files in a parallel computing system with dynamic block size

    Science.gov (United States)

    Bent, John M.; Faibish, Sorin; Grider, Gary

    2015-11-10

    Improved techniques are provided for parallel writing of data to a shared object in a parallel computing system. A method is provided for storing data generated by a plurality of parallel processes to a shared object in a parallel computing system. The method is performed by at least one of the processes and comprises: dynamically determining a block size for storing the data; exchanging a determined amount of the data with at least one additional process to achieve a block of the data having the dynamically determined block size; and writing the block of the data having the dynamically determined block size to a file system. The determined block size comprises, e.g., a total amount of the data to be stored divided by the number of parallel processes. The file system comprises, for example, a log structured virtual parallel file system, such as a Parallel Log-Structured File System (PLFS).

  1. Using impulses to control the convergence toward invariant surfaces of continuous dynamical systems

    International Nuclear Information System (INIS)

    Marão, José; Liu Xinzhi; Figueiredo, Annibal

    2012-01-01

    Let us consider a smooth invariant surface S of a given ordinary differential equations system. In this work we develop an impulsive control method in order to assure that the trajectories of the controlled system converge toward the surface S. The method approach is based on a property of a certain class of invariant surfaces whose the dynamics associated to their transverse directions can be described by a non-autonomous linear system. This fact allows to define an impulsive system which drives the trajectories toward the surface S. Also, we set up a definition of local stability exponents which can be associated to such kind of invariant surface.

  2. Ocean current surface measurement using dynamic elevations obtained by the GEOS-3 radar altimeter

    Science.gov (United States)

    Leitao, C. D.; Huang, N. E.; Parra, C. G.

    1977-01-01

    Remote Sensing of the ocean surface from the GEOS-3 satellite using radar altimeter data has confirmed that the altimeter can detect the dynamic ocean topographic elevations relative to an equipotential surface, thus resulting in a reliable direct measurement of the ocean surface. Maps of the ocean dynamic topography calculated over a one month period and with 20 cm contour interval are prepared for the last half of 1975. The Gulf Stream is observed by the rapid slope change shown by the crowding of contours. Cold eddies associated with the current are seen as roughly circular depressions.

  3. Respiratory quotient: innovative method for monitoring ‘Royal Gala’ apple storage in a dynamic controlled atmosphere

    Directory of Open Access Journals (Sweden)

    Anderson Weber

    2015-02-01

    Full Text Available Apples (Malus domestica, Borkh. which are not stored at low temperature or in a properly controlled atmosphere (CA may have a high metabolic rate during the postharvest stage resulting in losses in quality. The aim of this study was to evaluate the quality of ‘Royal Gala’ apple fruit stored in accordance with a new method of dynamic controlled atmosphere (DCA.The respiratory quotient (RQ was monitored at two temperatures which were then compared using a commercially available technology based on chlorophyll fluorescence DCA (DCA-CF and static CA. Ethylene production and respiration rates were lower in apples stored in DCA than in CA, as a result of lower 1-aminocyclopropane-1-carboxylate oxidase activity, especially in apples stored in DCA-RQ2. Flesh firmness of apples stored in DCA did not differ from those stored in CA. Apples stored at 1 °C had less flesh breakdown occurrence and a high percentage of healthy fruit. ‘Royal Gala’ stored at DCA-RQ2 had less flesh breakdown than apples stored in CA; however, the apples stored in DCA-CF did not differ from those stored in DCA-RQ2 and CA. Apples stored at the highest RQ value (6 and 4, especially at 0.5 °C, had low O2 injury occurrence after storage. However the increase in temperature to 1.0 °C, reduced the occurrence of this disorder. Therefore, storage in DCA-RQ2 at 1 °C or DCA-CF at 0.5 °C are the recommendations of preference for ensuring maintenance of quality in ‘Royal Gala’ apples after eight months of storage.

  4. Evaluation of bubbler/diaphragm techniques to measure surface level in the waste storage tanks

    International Nuclear Information System (INIS)

    Peters, T.J.; Hickman, B.J.; Colson, J.B.

    1993-10-01

    This report describes the results of tests conducted at the Pacific Northwest Laboratory (PNL) to determine if a bubbler technique can be used to determine the surface level in the waste tanks. Two techniques were evaluated. The first technique is a standard bubbler system in which a tube is placed below the surface of the liquid to be measured and air pressure inside a tube is increased until bubbles begin to become emitted from the tube. The air pressure then is a function of the pressure at the bottom of the tube. The second technique involves a system similar to the standard bubbler technique, but instead of bubbles being released into the material to be gauged, air pressure is increased against a diaphragm until enough pressure is applied to overcome the pressure of the liquid at the given depth, at which time the air then flows in a return loop back to a vent. The advantage of the diaphragm system is that it is a sealed system; thus no air is released into the waste tank materials, and it is not possible for the waste tank materials to get into the air flow. Based on the results of the tests conducted in this program, it appears that the bubbler and diaphragm systems that were tested could not be used for accurate measurements of the level in the waste tanks. Both exhibited deposits of simulated waste tank material at the end of the devices which affected the ability of the gauge to accurately determine changes in the surface level even though the measured value of the level was inaccurate. Further investigations into the cause of this inaccuracy may be warranted. Alternate diaphragm materials may improve the performance of this gauge

  5. Molecular dynamics simulation of temperature effects on low energy near-surface cascades and surface damage in Cu

    Science.gov (United States)

    Zhu, Guo; Sun, Jiangping; Guo, Xiongxiong; Zou, Xixi; Zhang, Libin; Gan, Zhiyin

    2017-06-01

    The temperature effects on near-surface cascades and surface damage in Cu(0 0 1) surface under 500 eV argon ion bombardment were studied using molecular dynamics (MD) method. In present MD model, substrate system was fully relaxed for 1 ns and a read-restart scheme was introduced to save total computation time. The temperature dependence of damage production was calculated. The evolution of near-surface cascades and spatial distribution of adatoms at varying temperature were analyzed and compared. It was found that near-surface vacancies increased with temperature, which was mainly due to the fact that more atoms initially located in top two layers became adatoms with the decrease of surface binding energy. Moreover, with the increase of temperature, displacement cascades altered from channeling-like structure to branching structure, and the length of collision sequence decreased gradually, because a larger portion of energy of primary knock-on atom (PKA) was scattered out of focused chain. Furthermore, increasing temperature reduced the anisotropy of distribution of adatoms, which can be ascribed to that regular registry of surface lattice atoms was changed with the increase of thermal vibration amplitude of surface atoms.

  6. Molecular dynamics simulation of temperature effects on low energy near-surface cascades and surface damage in Cu

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Guo; Sun, Jiangping; Guo, Xiongxiong; Zou, Xixi; Zhang, Libin; Gan, Zhiyin, E-mail: ganzhiyin@126.com

    2017-06-15

    The temperature effects on near-surface cascades and surface damage in Cu(0 0 1) surface under 500 eV argon ion bombardment were studied using molecular dynamics (MD) method. In present MD model, substrate system was fully relaxed for 1 ns and a read-restart scheme was introduced to save total computation time. The temperature dependence of damage production was calculated. The evolution of near-surface cascades and spatial distribution of adatoms at varying temperature were analyzed and compared. It was found that near-surface vacancies increased with temperature, which was mainly due to the fact that more atoms initially located in top two layers became adatoms with the decrease of surface binding energy. Moreover, with the increase of temperature, displacement cascades altered from channeling-like structure to branching structure, and the length of collision sequence decreased gradually, because a larger portion of energy of primary knock-on atom (PKA) was scattered out of focused chain. Furthermore, increasing temperature reduced the anisotropy of distribution of adatoms, which can be ascribed to that regular registry of surface lattice atoms was changed with the increase of thermal vibration amplitude of surface atoms.

  7. A Dynamic Consensus Algorithm to Adjust Virtual Impedance Loops for Discharge Rate Balancing of AC Microgrid Energy Storage Units

    DEFF Research Database (Denmark)

    Guan, Yajuan; Meng, Lexuan; Li, Chendan

    2018-01-01

    A dynamic consensus algorithm (DCA)-based coordinated secondary control with an autonomous current-sharing control strategy is proposed in this paper for balancing the discharge rate of energy storage systems (ESSs) in an islanded AC microgrid. The DCA is applied for information sharing between......, the proposed approach can provide higher system reliability, expandability, and flexibility due to its distributed control architecture. The proposed controller can effectively prevent operation failure caused by over-current and unintentional outage of DGs by means of balanced discharge rate control. It can...... also provide fast response and accurate current sharing performance. A generalizable linearized state-space model for n-DG network in the z-domain is also derived and proposed in this paper; the model includes electrical, controller, and communication parts. The system stability and parameter...

  8. Self-Excited Induction Generator Based Microgrid with Supercapacitor Energy Storage to Support the Start-up of Dynamic Loads

    Directory of Open Access Journals (Sweden)

    ION, C. P.

    2018-05-01

    Full Text Available A supercapacitor storage system (SCSS is used for improving the dynamic performances of a microgrid (MG fed by a self-excited induction generator (SEIG, in the case of the direct start-up of an induction motor (IM of comparable power. The primary control system contains a voltage source inverter (VSI with a dump load (DL, to which the SCSS is added. The control strategy for the SCSS consists of injecting power into the VSI DC-link when, because of the overload created by the IM, the DC voltage decreases under the acceptable limit. Thus, the overall performance of the SEIG-supplied MG is significantly improved. Simulations and experimental results accomplished on a laboratory-scale MG validate the effectiveness of the proposed control structure.

  9. Data demonstrating the influence of the latent storage efficiency on the dynamic thermal characteristics of a PCM layer

    Directory of Open Access Journals (Sweden)

    D. Mazzeo

    2017-06-01

    Full Text Available Dynamic thermal characteristics, for each month of the year, of PCM layers with different melting temperatures and thermophysical properties, in a steady periodic regime, were determined (Mazzeo et al., 2017 [1]. The layer is subjected to climatic conditions characterizing two locations, one with a continental climate and the second one with a Mediterranean climate. This data article provides detailed numerical data, as a function of the latent storage efficiency, including monthly average daily values: of the latent energy fraction, of the decrement factors of the temperature, of the heat flux and of the energy, and of the time lags of the maximum and minimum peaks of the temperature and of the heat flux.

  10. Sediment Mobilization and Storage Dynamics of a Debris Flow Impacted Stream Channel using Multi-Temporal Structure from Motion Photogrammetry

    Science.gov (United States)

    Bailey, T. L.; Sutherland-Montoya, D.

    2015-12-01

    High resolution topographic analysis methods have become important tools in geomorphology. Structure from Motion photogrammetry offers a compelling vehicle for geomorphic change detection in fluvial environments. This process can produce arbitrarily high resolution, geographically registered spectral and topographic coverages from a collection of overlapping digital imagery from consumer cameras. Cuneo Creek has had three historically observed episodes of rapid aggradation (1955, 1964, and 1997). The debris flow deposits continue to be major sources of sediment sixty years after the initial slope failure. Previous studies have monitored the sediment storage volume and particle size since 1976 (in 1976, 1982, 1983, 1985, 1986, 1987, 1998, 2003). We reoccupied 3 previously surveyed stream cross sections on Sept 30, 2014 and March 30, 2015, and produced photogrammetric point clouds using a pole mounted camera with a remote view finder to take nadir view images from 4.3 meters above the channel bed. Ground control points were registered using survey grade GPS and typical cross sections used over 100 images to build the structure model. This process simultaneously collects channel geometry and we used it to also generate surface texture metrics, and produced DEMs with point cloud densities above 5000 points / m2. In the period between the surveys, a five year recurrence interval discharge of 20 m3/s scoured the channel. Surface particle size distribution has been determined for each observation period using image segmentation algorithms based on spectral distance and compactness. Topographic differencing between the point clouds shows substantial channel bed mobilization and reorganization. The net decline in sediment storage is in excess of 4 x 10^5 cubic meters since the 1964 aggradation peak, with associated coarsening of surface particle sizes. These new methods provide a promising rapid assessment tool for measurement of channel responses to sediment inputs.

  11. Surface dynamics of voltage-gated ion channels

    Science.gov (United States)

    Heine, Martin; Ciuraszkiewicz, Anna; Voigt, Andreas; Heck, Jennifer; Bikbaev, Arthur

    2016-01-01

    ABSTRACT Neurons encode information in fast changes of the membrane potential, and thus electrical membrane properties are critically important for the integration and processing of synaptic inputs by a neuron. These electrical properties are largely determined by ion channels embedded in the membrane. The distribution of most ion channels in the membrane is not spatially uniform: they undergo activity-driven changes in the range of minutes to days. Even in the range of milliseconds, the composition and topology of ion channels are not static but engage in highly dynamic processes including stochastic or activity-dependent transient association of the pore-forming and auxiliary subunits, lateral diffusion, as well as clustering of different channels. In this review we briefly discuss the potential impact of mobile sodium, calcium and potassium ion channels and the functional significance of this for individual neurons and neuronal networks. PMID:26891382

  12. Probing Ultrafast Electron Dynamics at Surfaces Using Soft X-Ray Transient Reflectivity Spectroscopy

    Science.gov (United States)

    Baker, L. Robert; Husek, Jakub; Biswas, Somnath; Cirri, Anthony

    The ability to probe electron dynamics with surface sensitivity on the ultrafast time scale is critical for understanding processes such as charge separation, injection, and surface trapping that mediate efficiency in catalytic and energy conversion materials. Toward this goal, we have developed a high harmonic generation (HHG) light source for femtosecond soft x-ray reflectivity. Using this light source we investigated the ultrafast carrier dynamics at the surface of single crystalline α-Fe2O3, polycrystalline α-Fe2O3, and the mixed metal oxide, CuFeO2. We have recently demonstrated that CuFeO2 in particular is a selective catalyst for photo-electrochemical CO2 reduction to acetate; however, the role of electronic structure and charge carrier dynamics in mediating catalytic selectivity has not been well understood. Soft x-ray reflectivity measurements probe the M2,3, edges of the 3d transition metals, which provide oxidation and spin state resolution with element specificity. In addition to chemical state specificity, these measurements are also surface sensitive, and by independently simulating the contributions of the real and imaginary components of the complex refractive index, we can differentiate between surface and sub-surface contributions to the excited state spectrum. Accordingly, this work demonstrates the ability to probe ultrafast carrier dynamics in catalytic materials with element and chemical state specificity and with surface sensitivity.

  13. Dynamic thermal behavior of building using phase change materials for latent heat storage

    Directory of Open Access Journals (Sweden)

    Selka Ghouti

    2015-01-01

    Full Text Available This study presents a two-dimensional model with a real size home composed of two-storey (ground and first floor spaces separated by a slab, enveloped by a wall with rectangular section containing phase change material (PCM in order to minimize energy consumption in the buildings. The main objective of the PCM-wall system is to decrease the temperature change from outdoor space before it reaches the indoor space during the daytime. The numerical approach uses effective heat capacity Ceff model with realistic outdoor climatic conditions of Tlemcen city, Algeria. The numerical results showed that by using PCM in wall as energy storage components may reduce the room temperature by about 6 to 7°C of temperature depending on the floor level (first floor spaces or ground floor spaces.

  14. Heissdampfreaktor (HDR) steel-containment-vessel and floodwater-storage-tank structural-dynamics tests

    International Nuclear Information System (INIS)

    Arendts, J.G.

    1982-01-01

    Inertance (vibration) testing of two significant vessels at the Heissdampfreaktor (HDR) facility, located near Kahl, West Germany, was recently completed. Transfer functions were obtained for determination of the modal properties (frequencies, mode shapes and damping) of the vessels using two different test methods for comparative purposes. One of the vessels tested was the steel containment vessel (SCV). The SCV is approximately 180 feet high and 65 feet in diameter with a 1.2-inch wall thickness. The other vessel, called the floodwater storage tank (FWST), is a vertically standing vessel approximately 40 feet high and 10 feet in diameter with a 1/2-inch wall thickness. The FWST support skirt is square (in plan views) with its corners intersecting the ellipsoidal bottom head near the knuckle region

  15. Structural assessment of a space station solar dynamic heat receiver thermal energy storage canister

    Science.gov (United States)

    Thompson, R. L.; Kerslake, T. W.; Tong, M. T.

    1988-01-01

    The structural performance of a space station thermal energy storage (TES) canister subject to orbital solar flux variation and engine cold start up operating conditions was assessed. The impact of working fluid temperature and salt-void distribution on the canister structure are assessed. Both analytical and experimental studies were conducted to determine the temperature distribution of the canister. Subsequent finite element structural analyses of the canister were performed using both analytically and experimentally obtained temperatures. The Arrhenius creep law was incorporated into the procedure, using secondary creep data for the canister material, Haynes 188 alloy. The predicted cyclic creep strain accumulations at the hot spot were used to assess the structural performance of the canister. In addition, the structural performance of the canister based on the analytically determined temperature was compared with that based on the experimentally measured temperature data.

  16. Water loss in table grapes: model development and validation under dynamic storage conditions

    Directory of Open Access Journals (Sweden)

    Ericsem PEREIRA

    2017-09-01

    Full Text Available Abstract Water loss is a critical problem affecting the quality of table grapes. Temperature and relative humidity (RH are essential in this process. Although mathematical modelling can be applied to measure constant temperature and RH impacts, it is proved that variations in storage conditions are normally encountered in the cold chain. This study proposed a methodology to develop a weight loss model for table grapes and validate its predictions in non-constant conditions of a domestic refrigerator. Grapes were maintained under controlled conditions and the weight loss was measured to calibrate the model. The model described the water loss process adequately and the validation tests confirmed its predictive ability. Delayed cooling tests showed that estimated transpiration rates in subsequent continuous temperature treatment was not significantly influenced by prior exposure conditions, suggesting that this model may be useful to estimate the weight loss consequences of interruptions in the cold chain.

  17. A dynamic optimization-based architecture for polygeneration microgrids with tri-generation, renewables, storage systems and electrical vehicles

    International Nuclear Information System (INIS)

    Bracco, Stefano; Delfino, Federico; Pampararo, Fabio; Robba, Michela; Rossi, Mansueto

    2015-01-01

    Highlights: • We describe two national special projects on smart grid. • We developed dynamic decision model based on a MPC architecture. • We developed an optimization model for microgrids, for a specific case study. - Abstract: An overall architecture, or Energy Management System (EMS), based on a dynamic optimization model to minimize operating costs and CO 2 emissions is formalized and applied to the University of Genova Savona Campus test-bed facilities consisting of a Smart Polygeneration Microgrid (SPM) and a Sustainable Energy Building (SEB) connected to such microgrid. The electric grid is a three phase low voltage distribution system, connecting many different technologies: three cogeneration micro gas turbines fed by natural gas, a photovoltaic field, three cogeneration Concentrating Solar Powered (CSP) systems (equipped with Stirling engines), an absorption chiller equipped with a storage tank, two types of electrical storage based on batteries technology (long term Na–Ni and short term Li-Ion ion), two electric vehicles charging stations, other electrical devices (inverters and smart metering systems), etc. The EMS can be used both for microgrids approximated as single bus bar (or one node) and for microgrids in which all buses are taken into account. The optimal operation of the microgrid is based on a central controller that receives forecasts and data from a SCADA system and that can schedule all dispatchable plants in the day ahead or in real time through an approach based on Model Predictive Control (MPC). The architecture is tested and applied to the case study of the Savona Campus

  18. Cellular automaton model for hydrogen transport dynamics through metallic surface

    International Nuclear Information System (INIS)

    Shimura, K.; Yamaguchi, K.; Terai, T.; Yamawaki, M.

    2002-01-01

    Hydrogen re-emission and re-combination at the surface of first wall materials are a crucial issue for the understanding of the fuel recycling and for the tritium inventory in plasma facing materials. It is know to be difficult to model the transient behaviour of those processes due to their complex time-transient nature. However, cellular automata (CA) are powerful tools to model such complex systems because of their nature of discreteness in both dependent and independent variables. Then the system can be represented by the fully local interactions between cells. For that reason, complex physical and chemical systems can be described by fairly simple manner. In this study, the kinetics of desorption of adsorbed hydrogen from an ideal metallic surface is modelled in CA. Thermal desorption is simulated with this model and the comparison with the theory of rate processes is performed to identify the validity of this model. The overall results show that this model is reasonable to express the desorption kinetics

  19. CESARR V.2 manual: Computer code for the evaluation of surface storage of low and medium level radioactive waste

    International Nuclear Information System (INIS)

    Moya Rivera, J.A.; Bolado Lavin, R.

    1997-01-01

    CESARR (Code for the safety evaluation of low and medium level radioactive waste storage). This code was developed for the safety probabilistic evaluations in the facilities of low-and medium level radioactive waste storage

  20. Salt impact studies at WIPP effects of surface storage of salt on microbial activity

    International Nuclear Information System (INIS)

    Rodriguez, A.L.

    1988-01-01

    The Waste Isolation Pilot Plant (WIPP) currently under construction in southeastern New Mexico is a research and development facility to demonstrate the safe disposal of transuranic waste in a deep geological formation (bedded salt). The Ecological Monitoring Program at WIPP is designed to detect and measure changes in the local ecosystem which may be the result of WIPP construction activities. The primary factor which may affect the system prior to waste emplacement is windblown salt from discrete stockpiles. Both vegetation and soil microbial processes should reflect changes in soil chemistry due to salt importation. Control and experimental (potentially affected) plots have been established at the site, and several parameters are measured quarterly in each plot as part of the soil microbial sampling subprogram. This subprogram was designed to monitor a portion of the biological community which can be affected by changes in the chemical properties at the soil surface

  1. Characterization of Qatar's surface carbonates for CO2 capture and thermochemical energy storage

    Science.gov (United States)

    Kakosimos, Konstantinos E.; Al-Haddad, Ghadeer; Sakellariou, Kyriaki G.; Pagkoura, Chrysa; Konstandopoulos, Athanasios G.

    2017-06-01

    Samples of surface carbonates were collected from three different areas of the Qatar peninsula. We employed material characterization techniques to examine the morphology and composition of the samples, while their CO2 capture capacity was assessed via multiple successive calcination-carbonation cycles. Our samples were mainly calcite and dolomite based. Calcite samples showed higher initial capacity of around 11 mmol CO2 g-1 which decayed rapidly to less than 2 mmol CO2 g-1. On the other hand, dolomite samples showed an excellent stability (˜15 cycles) with a capacity of 6 mmol CO2 g-1. The performance of the dolomite samples is better compared to other similar natural samples, from literature. A promising result for future studies towards improving their performance by physical and chemical modification.

  2. The dispersal and impact of salt from surface storage piles the Waste Isolation Pilot Plant

    International Nuclear Information System (INIS)

    Reith, C.C.; Louderbough, E.T.

    1986-01-01

    A comprehensive program of ecological studies occurs at the Waste Isolation Pilot Plant (WIPP) in an effort to detect and quantify impacts of excavated salt which is stored on the surface in two piles: one having originated in 1980, the other in 1984. Both piles are surrounded by berms which channel runoff to holding ponds, so nearly all dispersal is due to the resuspension, transport, and deposition of salt particles by wind. Ecological parameters which have been monitored since 1984 include: visual evidence (via photography), soil properties, microbial activity, leaf-litter decomposition, seedling emergence, plant foliar cover, and plant species diversity. These are periodically assessed at experimental plots near the salt piles, and at control plots several kilometers away

  3. Evaluation of pressure transducers to measure surface level in the waste storage tanks

    International Nuclear Information System (INIS)

    Peters, T.J.; Colson, J.B.

    1994-06-01

    This report describes the results of tests conducted at the Pacific Northwest Laboratory (PNL) to determine if pressure transducers can be used to measure the surface level in the waste tanks. A survey was first conducted to evaluate which, if any, commercially available pressure transducers were available that could meet the requirements for use in the waste tanks. More than 35 companies were contacted to determine if they manufactured a pressure transducer that could be used in the 101-SY waste tank. The three basic requirements for a pressure transducer for this application were that they were radiation-hardened, could withstand a caustic environment, and were certified to be intrinsically safe. No manufacturer was able to meet all three of these requirements with a commercially available product. Seven companies were able to meet the requirements for being radiation-hardened and being able to withstand the caustic environment. However, only two of the nine companies were willing to supply a pressure transducer for laboratory testing. The two pressure transducers that were tested in this program were the VEGA D36-38 from HiTech Technologies, Inc., and the KP-1911-A from Kaman Instrumentation Corporation. Pressure transducers operate on the principle that the pressure at the location of a sensor increases directly with the depth of the liquid above it. A liquid is required in order for these devices to operate. For these tests, water was first used to determine the ideal operation of the devices, then the devices were placed in a 101-SY waste tank simulant. The simulant had a specific gravity of 1.96 and had the consistency similar to the convective layer in the 101-SY waste tank. In order to determine the surface level with pressure transducers, the density of the material needs to be known

  4. CO2 leakage from carbon dioxide capture and storage (CCS) systems affects organic matter cycling in surface marine sediments.

    Science.gov (United States)

    Rastelli, Eugenio; Corinaldesi, Cinzia; Dell'Anno, Antonio; Amaro, Teresa; Greco, Silvestro; Lo Martire, Marco; Carugati, Laura; Queirós, Ana M; Widdicombe, Stephen; Danovaro, Roberto

    2016-12-01

    Carbon dioxide capture and storage (CCS), involving the injection of CO 2 into the sub-seabed, is being promoted worldwide as a feasible option for reducing the anthropogenic CO 2 emissions into the atmosphere. However, the effects on the marine ecosystems of potential CO 2 leakages originating from these storage sites have only recently received scientific attention, and little information is available on the possible impacts of the resulting CO 2 -enriched seawater plumes on the surrounding benthic ecosystem. In the present study, we conducted a 20-weeks mesocosm experiment exposing coastal sediments to CO 2 -enriched seawater (at 5000 or 20,000 ppm), to test the effects on the microbial enzymatic activities responsible for the decomposition and turnover of the sedimentary organic matter in surface sediments down to 15 cm depth. Our results indicate that the exposure to high-CO 2 concentrations reduced significantly the enzymatic activities in the top 5 cm of sediments, but had no effects on subsurface sediment horizons (from 5 to 15 cm depth). In the surface sediments, both 5000 and 20,000 ppm CO 2 treatments determined a progressive decrease over time in the protein degradation (up to 80%). Conversely, the degradation rates of carbohydrates and organic phosphorous remained unaltered in the first 2 weeks, but decreased significantly (up to 50%) in the longer term when exposed at 20,000 ppm of CO 2 . Such effects were associated with a significant change in the composition of the biopolymeric carbon (due to the accumulation of proteins over time in sediments exposed to high-pCO 2 treatments), and a significant decrease (∼20-50% at 5000 and 20,000 ppm respectively) in nitrogen regeneration. We conclude that in areas immediately surrounding an active and long-lasting leak of CO 2 from CCS reservoirs, organic matter cycling would be significantly impacted in the surface sediment layers. The evidence of negligible impacts on the deeper sediments should be

  5. Dynamic potential and surface morphology study of sertraline membrane sensors

    Science.gov (United States)

    Khater, M.M.; Issa, Y.M.; Hassib, H.B.; Mohammed, S.H.

    2014-01-01

    New rapid, sensitive and simple electrometric method was developed to determine sertraline hydrochloride (Ser-Cl) in its pure raw material and pharmaceutical formulations. Membrane sensors based on heteropolyacids as ion associating material were prepared. Silicomolybdic acid (SMA), silicotungstic acid (STA) and phosphomolybdic acid (PMA) were used. The slope and limit of detection are 50.00, 60.00 and 53.24 mV/decade and 2.51, 5.62 and 4.85 μmol L−1 for Ser-ST, Ser-PM and Ser-SM membrane sensors, respectively. Linear range is 0.01–10.00 for the three sensors. These new sensors were used for the potentiometric titration of Ser-Cl using sodium tetraphenylborate as titrant. The surface morphologies of the prepared membranes with and without the modifier (ion-associate) were studied using scanning and atomic force microscopes. PMID:26257944

  6. Gallium surface diffusion on GaAs (001) surfaces measured by crystallization dynamics of Ga droplets

    International Nuclear Information System (INIS)

    Bietti, Sergio; Somaschini, Claudio; Esposito, Luca; Sanguinetti, Stefano; Fedorov, Alexey

    2014-01-01

    We present accurate measurements of Ga cation surface diffusion on GaAs surfaces. The measurement method relies on atomic force microscopy measurement of the morphology of nano–disks that evolve, under group V supply, from nanoscale group III droplets, earlier deposited on the substrate surface. The dependence of the radius of such nano-droplets on crystallization conditions gives direct access to Ga diffusion length. We found an activation energy for Ga on GaAs(001) diffusion E A =1.31±0.15 eV, a diffusivity prefactor of D 0  = 0.53(×2.1±1) cm 2 s −1 that we compare with the values present in literature. The obtained results permit to better understand the fundamental physics governing the motion of group III ad–atoms on III–V crystal surfaces and the fabrication of designable nanostructures.

  7. Measuring and modeling surface sorption dynamics of organophosphate flame retardants on impervious surfaces

    Data.gov (United States)

    U.S. Environmental Protection Agency — The data presented in this data file is a product of a journal publication. The dataset contains measured and model predicted OPFRs gas-phase and surface-phase...

  8. CBS Genome Atlas Database: a dynamic storage for bioinformatic results and sequence data

    DEFF Research Database (Denmark)

    Hallin, Peter Fischer; Ussery, David

    2004-01-01

    , these results counts to more than 220 pieces of information. The backbone of this solution consists of a program package written in Perl, which enables administrators to synchronize and update the database content. The MySQL database has been connected to the CBS web-server via PHP4, to present a dynamic web...... and frequent addition of new models are factors that require a dynamic database layout. Using basic tools like the GNU Make system, csh, Perl and MySQL, we have created a flexible database environment for storing and maintaining such results for a collection of complete microbial genomes. Currently...... content for users outside the center. This solution is tightly fitted to existing server infrastructure and the solutions proposed here can perhaps serve as a template for other research groups to solve database issues....

  9. Mobility and Congestion in Dynamical Multilayer Networks with Finite Storage Capacity

    Science.gov (United States)

    Manfredi, S.; Di Tucci, E.; Latora, V.

    2018-02-01

    Multilayer networks describe well many real interconnected communication and transportation systems, ranging from computer networks to multimodal mobility infrastructures. Here, we introduce a model in which the nodes have a limited capacity of storing and processing the agents moving over a multilayer network, and their congestions trigger temporary faults which, in turn, dynamically affect the routing of agents seeking for uncongested paths. The study of the network performance under different layer velocities and node maximum capacities reveals the existence of delicate trade-offs between the number of served agents and their time to travel to destination. We provide analytical estimates of the optimal buffer size at which the travel time is minimum and of its dependence on the velocity and number of links at the different layers. Phenomena reminiscent of the slower is faster effect and of the Braess' paradox are observed in our dynamical multilayer setup.

  10. Splash Dynamics of Watercolors on Dry, Wet, and Cooled Surfaces

    Science.gov (United States)

    Baron, David; Vaidya, Ashwin; Su, Haiyan

    2015-11-01

    In his classic study in 1908, A.M. Worthington gave a thorough account of splashes and their formation through visualization experiments. In more recent times, there has been renewed interest in this subject, and much of the underlying physics behind Worthington's experiments has now been clarified. One specific set of such recent studies, which motivates this paper, concerns the fluid dynamics behind Jackson Pollock's drip paintings. The physical processes and the mathematical structures hidden in his works have received serious attention and made the scientific pursuit of art a compelling area of exploration. Our work explores the interaction of watercolors with watercolor paper. Specifically, we conduct experiments to analyze the settling patterns of droplets of watercolor paint on wet and frozen paper. Variations in paint viscosity, paper roughness, paper temperature, and the height of a released droplet are examined from time of impact, through its transient stages, until its final, dry state. Observable phenomena such as paint splashing, spreading, fingering, branching, rheological deposition, and fractal patterns are studied in detail and classified in terms of the control parameters.

  11. A Lagrangian cylindrical coordinate system for characterizing dynamic surface geometry of tubular anatomic structures.

    Science.gov (United States)

    Lundh, Torbjörn; Suh, Ga-Young; DiGiacomo, Phillip; Cheng, Christopher

    2018-03-03

    Vascular morphology characterization is useful for disease diagnosis, risk stratification, treatment planning, and prediction of treatment durability. To quantify the dynamic surface geometry of tubular-shaped anatomic structures, we propose a simple, rigorous Lagrangian cylindrical coordinate system to monitor well-defined surface points. Specifically, the proposed system enables quantification of surface curvature and cross-sectional eccentricity. Using idealized software phantom examples, we validate the method's ability to accurately quantify longitudinal and circumferential surface curvature, as well as eccentricity and orientation of eccentricity. We then apply the method to several medical imaging data sets of human vascular structures to exemplify the utility of this coordinate system for analyzing morphology and dynamic geometric changes in blood vessels throughout the body. Graphical abstract Pointwise longitudinal curvature of a thoracic aortic endograft surface for systole and diastole, with their absolute difference.

  12. Dynamic Auditing Protocol for Efficient and Secure Data Storage in Cloud Computing

    OpenAIRE

    J. Noorul Ameen; J. Jamal Mohamed; N. Nilofer Begam

    2014-01-01

    Cloud computing, where the data has been stored on cloud servers and retrieved by users (data consumers) the data from cloud servers. However, there are some security challenges which are in need of independent auditing services to verify the data integrity and safety in the cloud. Until now a numerous methods has been developed for remote integrity checking whichever only serve for static archive data and cannot be implemented to the auditing service if the data in the cloud is being dynamic...

  13. Dynamic strain analysis of structures employing digital signal processing, storage and display

    Energy Technology Data Exchange (ETDEWEB)

    Patwardhan, P K; Misra, V M; Kumar, Surendra

    1975-01-01

    A multi-channel digital technique has been adopted for analysing wave patterns of stresses and strains in structures, particularly under dynamic conditions. This technique provides adequate signal to noise discrimination and high sensitivity for very small (few milli-volts) and slow varying signals (few Hz to 100 Hz.), and A-D conversion accompined by live display during the course of data gathering and computer compatible output. This system also provides fast response because of inherent 50 MHz digitising speed and a large dynamic range of 1024 discrete signal steps. The signals can be suitably fed to the A-D converter (50 MHz) or can be analysed employing frequency modulation techniques and time mode operation of the analyser. The data can be gathered in the field on cassette tapes and replayed in the laboratory for detailed analysis. This technique would provide a versatile system for dynamic analysis of structures under varying conditions. e.g. structures in nuclear power systems, such as testing of end fittings, calandria, vibration testing and measurements exploying pressure transducers.

  14. Dynamic strain analysis of structures employing digital signal processing, storage and display

    International Nuclear Information System (INIS)

    Patwardhan, P.K.; Misra, V.M.; Kumar, Surendra

    1975-01-01

    A multi-channel digital technique has been adopted for analysing wave patterns of stresses and strains in structures, particularly under dynamic conditions. This technique provides adequate signal to noise discrimination and high sensitivity for very small (few milli-volts) and slow varying signals (few Hz to 100 Hz.), A-D conversion accompined by live display during the course of data gathering and computer compatible output. This system also provides fast response because of inherent 50 MHz digitising speed and a large dynamic range of 1024 discrete signal steps. The signals can be suitably fed to the A-D converter (50 MHz) or can be analysed employing frequency modulation techniques and time mode operation of the analyser. The data can be gathered in the field on cassette tapes and replayed in the laboratory for detailed analysis. This technique would provide a versatile system for dynamic analysis of structures under varying conditions. e.g. structures in nuclear power systems, such as testing of end fittings, calandria, vibration testing and measurements exploying pressure transducers. (author)

  15. Evaluation of Seasonality in Shallow Groundwater Dynamics and Storage in an Urban Prairie Nature Preserve Using a High-Frequency Sensing Network

    Science.gov (United States)

    Rivera, V. A.; Hernandez-Gonzalez, L. M.; Phillips, C. B.; Nair, A.; Negri, M. C.; Gnaedinger, K. J.; Miller, W. M.; Packman, A. I.

    2017-12-01

    Changing regional climate applies stresses to urban areas in the form of altered weather patterns, requiring new strategies for stormwater runoff management and flood mitigation. At the same time, the proportion of people residing in urban areas is increasing and cities are turning to greenspace as a tool for managing runoff. Gensburg Markham Prairie (GMP), located in Markham, Illinois south of Chicago, is an urban prairie nature preserve and a U.S. National Natural Landmark. Owned by Northeastern Illinois University and managed by the Nature Conservancy, GMP receives runoff from surrounding urban areas and provides valuable stormwater storage, while also hosting high biodiversity and providing critical habitat for sensitive and endemic. A successful management strategy for GMP should preserve both of these valuable ecosystem services. To understand GMP's role within the urban environment, we installed a suite of instruments in 2016 and 2017 to measure surface and groundwater levels, rainfall, soil moisture, and electrical conductivity throughout the prairie. This monitoring network includes 40 sensors collecting high frequency data (every 30 minutes). We are also collecting monthly distributed surface and groundwater samples to quantify a range of anions and cations that signal potentially detrimental anthropogenic impacts on the prairie. In addition, we are using historical and ongoing plant distribution surveys to explore the interactions between spatial patterns in vegetation and water dynamics in the prairie. The high measurement frequency and large diversity of sensor types supports holistic investigation of the response of the prairie to diverse events, including summer thunderstorms, winter road salt runoff, and spring snowmelt. The 18 months of data collected to date reveals clear patterns in response to weather events with influence from soil type and spatial variables. We are using time-series analysis with MODFLOW modelling to explore surface

  16. Use of ground-water reservoirs for storage of surface water in the San Joaquin Valley, California

    Science.gov (United States)

    Davis, G.H.; Lofgren, B.E.; Mack, Seymour

    1964-01-01

    The San Joaquin Valley includes roughly the southern two-thirds of the Central Valley of California, extending 250 miles from Stockton on the north to Grapevine at the foot of the Tehachapi Mountains. The valley floor ranges in width from 25 miles near Bakersfield to about 55 miles near Visalia; it has a surface area of about 10,000 square miles. More than one-quarter of all the ground water pumped for irrigation in the United States is used in this highly productive valley. Withdrawal of ground water from storage by heavy pumping not only provides a needed irrigation water supply, but it also lowers the ground-water level and makes storage space available in which to conserve excess water during periods of heavy runoff. A storage capacity estimated to be 93 million acre-feet to a depth of 200 feet is available in this ground-water reservoir. This is about nine times the combined capacity of the existing and proposed surface-water reservoirs in the San Joaquin Valley under the California Water Plan. The landforms of the San Joaquin Valley include dissected uplands, low plains and fans, river flood plains and channels, and overflow lands and lake bottoms. Below the land surface, unconsolidated sediments derived from the surrounding mountain highlands extend downward for hundreds of feet. These unconsolidated deposits, consisting chiefly of alluvial deposits, but including some widespread lacustrine sediments, are the principal source of ground water in the valley. Ground water occurs under confined and unconfined conditions in the San Joaquin Valley. In much of the western, central, and southeastern parts of the valley, three distinct ground-water reservoirs are present. In downward succession these are 1) a body of unconfined and semiconfined fresh water in alluvial deposits of Recent, Pleistocene, and possibly later Pliocene age, overlying the Corcoran clay member of the Tulare formation; 2) a body of fresh water confined beneath the Corcoran clay member, which

  17. Modeling wood dynamics, jam formation, and sediment storage in a gravel-bed stream

    Science.gov (United States)

    Eaton, B. C.; Hassan, M. A.; Davidson, S. L.

    2012-12-01

    In small and intermediate sized streams, the interaction between wood and bed material transport often determines the nature of the physical habitat, which in turn influences the health of the stream's ecosystem. We present a stochastic model that can be used to simulate the effects on physical habitat of forest fires, climate change, and other environmental disturbances that alter wood recruitment. The model predicts large wood (LW) loads in a stream as well as the volume of sediment stored by the wood; while it is parameterized to describe gravel bed streams similar to a well-studied field prototype, Fishtrap Creek, British Columbia, it can be calibrated to other systems as well. In the model, LW pieces are produced and modified over time as a result of random tree-fall, LW breakage, LW movement, and piece interaction to form LW jams. Each LW piece traps a portion of the annual bed material transport entering the reach and releases the stored sediment when the LW piece is entrained and moved. The equations governing sediment storage are based on a set of flume experiments also scaled to the field prototype. The model predicts wood loads ranging from 70 m3/ha to more than 300 m3/ha, with a mean value of 178 m3/ha: both the range and the mean value are consistent with field data from streams with similar riparian forest types and climate. The model also predicts an LW jam spacing that is consistent with field data. Furthermore, our modeling results demonstrate that the high spatial and temporal variability in sediment storage, sediment transport, and channel morphology associated with LW-dominated streams occurs only when LW pieces interact and form jams. Model runs that do not include jam formation are much less variable. These results suggest that river restoration efforts using engineered LW pieces that are fixed in place and not permitted to interact will be less successful at restoring the geomorphic processes responsible for producing diverse, productive

  18. Assessing biogeochemical cycling and transient storage of surface water in Eastern Siberian streams using short-term solute additions

    Science.gov (United States)

    Schade, J. D.; Seybold, E.; Drake, T. W.; Bulygina, E. B.; Bunn, A. G.; Chandra, S.; Davydov, S.; Frey, K. E.; Holmes, R. M.; Sobczak, W. V.; Spektor, V. V.; Zimov, S. A.; Zimov, N.

    2009-12-01

    Recent studies highlight the role of stream networks in the processing of nutrient and organic matter inputs from the surrounding watershed. Clear evidence exists that streams actively regulate fluxes of carbon, nitrogen, and phosphorus from upland terrestrial ecosystems to downstream aquatic environments. This is of particular interest in Arctic streams because of the potential impact of permafrost thaw due to global warming on inputs of nutrients and organic matter to small streams high in the landscape. Knowledge of functional characteristics of these stream ecosystems is paramount to our ability to predict changes in stream ecosystems as climate changes. Biogeochemical models developed by stream ecologists, specifically nutrient spiraling models, provide a set of metrics that we used to assess nutrient processing rates in several streams in the Eastern Siberian Arctic. We quantified these metrics using solute addition experiments in which nitrogen and phosphorus were added simultaneously with chloride as a conservative tracer. We focused on 5 streams, three flowing across upland yedoma soils and two floodplain streams. Yedoma streams showed higher uptake of N than P, suggesting N limitation of biological processes, with large variation between these three streams in the severity of N limitation. Floodplain streams both showed substantially higher P uptake than N uptake, indicating strong P limitation. Given these results, it is probable that these two types of streams will respond quite differently to changes in nutrient and organic matter inputs as permafrost thaws. Furthermore, uptake was strongly linked to discharge and transient storage of surface water, measured using temporal patterns of the conservative tracer, with higher nutrient uptake in low discharge, high transient storage streams. Given the possibility that both discharge and nutrient inputs will increase as permafrost thaws, longer-term nutrient enrichment experiments are needed to develop

  19. Investigation and optimization of transverse non-linear beam dynamics in the high-energy storage ring HESR

    Energy Technology Data Exchange (ETDEWEB)

    Welsch, Dominic Markus

    2010-03-10

    The High-Energy Storage Ring (HESR) is part of the upcoming Facility for Antiproton and Ion Research (FAIR) which is planned as a major extension to the present facility of the Helmholtzzentrum fuer Schwerionenforschung (GSI) in Darmstadt. The HESR will provide antiprotons in the momentum range from 1.5 to 15 GeV/c for the internal target experiment PANDA. The demanding requirements of PANDA in terms of beam quality and luminosity together with a limited production rate of antiprotons call for a long beam life time and a minimum of beam loss. Therefore, an effective closed orbit correction and a sufficiently large dynamic aperture of the HESR are crucial. With this thesis I present my work on both of these topics. The expected misalignments of beam guiding magnets have been estimated and used to simulate the closed orbit in the HESR. A closed orbit correction scheme has been developed for different ion optical settings of the HESR and numerical simulations have been performed to validate the scheme. The proposed closed orbit correction method which uses the orbit response matrix has been benchmarked at the Cooler Synchrotron COSY of the Forschungszentrum Juelich. A chromaticity correction scheme for the HESR consisting of sextupole magnets has been developed to reduce tune spread and thus to minimize the emittance growth caused by betatron resonances. The chromaticity correction scheme has been optimized through dynamic aperture calculations. The estimated field errors of the HESR dipole and quadrupole magnets have been included in the non-linear beam dynamics studies. Investigations concerning their optimization have been carried out. The ion optical settings of the HESR have been improved using dynamic aperture calculations and the technique of frequency map analysis. The related diffusion coefficient was also used to predict long-term stability based on short-term particle tracking. With a reasonable reduction of the quadrupole magnets field errors and a

  20. Modeling land-surface/atmosphere dynamics for CHAMMP

    International Nuclear Information System (INIS)

    Gutowski, W.J. Jr.

    1993-01-01

    Project progress is described on a DOE CHAMP project to model the land-surface/atmosphere coupling in a heterogeneous environment. This work is a collaboration between scientists at Iowa State University and the University of New Hampshire. Work has proceeded in two areas: baseline model coupling and data base development for model validation. The core model elements (land model, atmosphere model) have been ported to the Principal Investigator's computing system and baseline coupling has commenced. The initial target data base is the set of observations from the FIFE field campaign, which is in the process of being acquired. For the remainder of the project period, additional data from the region surrounding the FIFE site and from other field campaigns will be acquired to determine how to best extrapolate results from the initial target region to the rest of the globe. In addition, variants of the coupled model will be used to perform experiments examining resolution requirements and coupling strategies for land-atmosphere coupling in a heterogeneous environment

  1. Calculation of surface potentials at the silica–water interface using molecular dynamics: Challenges and opportunities

    Science.gov (United States)

    Lowe, Benjamin M.; Skylaris, Chris-Kriton; Green, Nicolas G.; Shibuta, Yasushi; Sakata, Toshiya

    2018-04-01

    Continuum-based methods are important in calculating electrostatic properties of interfacial systems such as the electric field and surface potential but are incapable of providing sufficient insight into a range of fundamentally and technologically important phenomena which occur at atomistic length-scales. In this work a molecular dynamics methodology is presented for interfacial electric field and potential calculations. The silica–water interface was chosen as an example system, which is highly relevant for understanding the response of field-effect transistors sensors (FET sensors). Detailed validation work is presented, followed by the simulated surface charge/surface potential relationship. This showed good agreement with experiment at low surface charge density but at high surface charge density the results highlighted challenges presented by an atomistic definition of the surface potential. This methodology will be used to investigate the effect of surface morphology and biomolecule addition; both factors which are challenging using conventional continuum models.

  2. Terrestrial N Cycling And C Storage: Some Insights From A Process-based Land Surface Model

    Science.gov (United States)

    Zaehle, S.; Friend, A. D.; Friedlingstein, P.

    2008-12-01

    We present results of a new land surface model, O-CN, which includes a process-based coupling between the terrestrial cycling of energy, water, carbon, and nitrogen. The model represents the controls of the terrestrial nitrogen (N) cycling on carbon (C) pools and fluxes through photosynthesis, respiration, changes in allocation, and soil organic matter decomposition, and explicitly accounts for N leaching and gaseous losses. O-CN has been shown to give realistic results in comparison to observations at a wide range of scales, including in situ flux measurements, productivity databases, and atmospheric CO2 concentration data. O-CN is run for three free air carbon dioxide enrichment (FACE) sites (Duke, Oak Ridge, Aspen), and reproduces observed magnitudes of changes in net primary productivity, foliage area and foliage N content. Several alternative hypotheses concerning the control of N on vegetation growth and decomposition, including effects of diluting foliage N concentrations, down-regulation of photosynthesis and respiration, acclimation of C allocation patterns and biological N fixation, are tested with respect to their effect on long- term C sequestration estimate. Differences in initial N availability, small transient changes in N inputs and the assumed plasticity of C:N stoichiometry can lead to substantial differences in the simulated long-term changes in productivity and C sequestration. We discuss the capacity of observations obtained at FACE sites to evaluate these alternative hypotheses, and investigate implications of a transient versus instantaneous increase in atmospheric carbon dioxide for the magnitude of the simulated limiting effect of N on C cycling. Finally, we re-examine earlier model-based assessments of the terrestrial C sequestration potential using a global transient O-CN simulation driven by increases in atmospheric CO2, N deposition and climatic changes over the 21st century.

  3. Accelerated sampling by infinite swapping of path integral molecular dynamics with surface hopping

    Science.gov (United States)

    Lu, Jianfeng; Zhou, Zhennan

    2018-02-01

    To accelerate the thermal equilibrium sampling of multi-level quantum systems, the infinite swapping limit of a recently proposed multi-level ring polymer representation is investigated. In the infinite swapping limit, the ring polymer evolves according to an averaged Hamiltonian with respect to all possible surface index configurations of the ring polymer and thus connects the surface hopping approach to the mean-field path-integral molecular dynamics. A multiscale integrator for the infinite swapping limit is also proposed to enable efficient sampling based on the limiting dynamics. Numerical results demonstrate the huge improvement of sampling efficiency of the infinite swapping compared with the direct simulation of path-integral molecular dynamics with surface hopping.

  4. Transmission-lattice based geometric phase analysis for evaluating the dynamic deformation of a liquid surface.

    Science.gov (United States)

    Shi, Wenxiong; Huang, Xianfu; Liu, Zhanwei

    2014-05-05

    Quantitatively measuring a dynamic liquid surface often presents a challenge due to high transparency, fluidity and specular reflection. Here, a novel Transmission-Lattice based Geometric Phase Analysis (TLGPA) method is introduced. In this method, a special lattice is placed underneath a liquid to be tested and, when viewed from above, the phase of the transmission-lattice image is modulated by the deformation of the liquid surface. Combining this with multi-directional Newton iteration algorithms, the dynamic deformation field of the liquid surface can be calculated from the phase variation of a series of transmission-lattice images captured at different moments. The developed method has the advantage of strong self-adaption ability to initial lattice rotational errors and this is discussed in detail. Dynamic 3D ripples formation and propagation was investigated and the results obtained demonstrated the feasibility of the method.

  5. Dynamic, electronically switchable surfaces for membrane protein microarrays.

    Science.gov (United States)

    Tang, C S; Dusseiller, M; Makohliso, S; Heuschkel, M; Sharma, S; Keller, B; Vörös, J

    2006-02-01

    Microarray technology is a powerful tool that provides a high throughput of bioanalytical information within a single experiment. These miniaturized and parallelized binding assays are highly sensitive and have found widespread popularity especially during the genomic era. However, as drug diagnostics studies are often targeted at membrane proteins, the current arraying technologies are ill-equipped to handle the fragile nature of the protein molecules. In addition, to understand the complex structure and functions of proteins, different strategies to immobilize the probe molecules selectively onto a platform for protein microarray are required. We propose a novel approach to create a (membrane) protein microarray by using an indium tin oxide (ITO) microelectrode array with an electronic multiplexing capability. A polycationic, protein- and vesicle-resistant copolymer, poly(l-lysine)-grafted-poly(ethylene glycol) (PLL-g-PEG), is exposed to and adsorbed uniformly onto the microelectrode array, as a passivating adlayer. An electronic stimulation is then applied onto the individual ITO microelectrodes resulting in the localized release of the polymer thus revealing a bare ITO surface. Different polymer and biological moieties are specifically immobilized onto the activated ITO microelectrodes while the other regions remain protein-resistant as they are unaffected by the induced electrical potential. The desorption process of the PLL-g-PEG is observed to be highly selective, rapid, and reversible without compromising on the integrity and performance of the conductive ITO microelectrodes. As such, we have successfully created a stable and heterogeneous microarray of biomolecules by using selective electronic addressing on ITO microelectrodes. Both pharmaceutical diagnostics and biomedical technology are expected to benefit directly from this unique method.

  6. Fluorescence quenching studies of potential-dependent DNA reorientation dynamics at glassy carbon electrode surfaces.

    Science.gov (United States)

    Li, Qin; Cui, Chenchen; Higgins, Daniel A; Li, Jun

    2012-09-05

    The potential-dependent reorientation dynamics of double-stranded DNA (ds-DNA) attached to planar glassy carbon electrode (GCE) surfaces were investigated. The orientation state of surface-bound ds-DNA was followed by monitoring the fluorescence from a 6-carboxyfluorescein (FAM6) fluorophore covalently linked to the distal end of the DNA. Positive potentials (i.e., +0.2 V vs open circuit potential, OCP) caused the ds-DNA to align parallel to the electrode surface, resulting in strong dipole-electrode quenching of FAM6 fluorescence. Switching of the GCE potential to negative values (i.e., -0.2 V vs OCP) caused the ds-DNA to reorient perpendicular to the electrode surface, with a concomitant increase in FAM6 fluorescence. In addition to the very fast (submilliseconds) dynamics of the initial reorientation process, slow (0.1-0.9 s) relaxation of FAM6 fluorescence to intermediate levels was also observed after potential switching. These dynamics have not been previously described in the literature. They are too slow to be explained by double layer charging, and chronoamperometry data showed no evidence of such effects. Both the amplitude and rate of the dynamics were found to depend upon buffer concentration, and ds-DNA length, demonstrating a dependence on the double layer field. The dynamics are concluded to arise from previously undetected complexities in the mechanism of potential-dependent ds-DNA reorientation. The possible origins of these dynamics are discussed. A better understanding of these dynamics will lead to improved models for potential-dependent ds-DNA reorientation at electrode surfaces and will facilitate the development of advanced electrochemical devices for detection of target DNAs.

  7. Influence of foundation mass and surface roughness on dynamic response of beam on dynamic foundation subjected to the moving load

    Science.gov (United States)

    Tran Quoc, Tinh; Khong Trong, Toan; Luong Van, Hai

    2018-04-01

    In this paper, Improved Moving Element Method (IMEM) is used to analyze the dynamic response of Euler-Bernoulli beam structures on the dynamic foundation model subjected to the moving load. The effects of characteristic foundation model parameters such as Winkler stiffness, shear layer based on the Pasternak model, viscoelastic dashpot and characteristic parameter of mass on foundation. Beams are modeled by moving elements while the load is fixed. Based on the principle of the publicly virtual balancing and the theory of moving element method, the motion differential equation of the system is established and solved by means of the numerical integration based on the Newmark algorithm. The influence of mass on foundation and the roughness of the beam surface on the dynamic response of beam are examined in details.

  8. Monitoring peptide-surface interaction by means of molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Nonella, Marco, E-mail: mnonella@pci.uzh.ch [Physikalisch-Chemisches Institut, Universitaet Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Seeger, Stefan, E-mail: sseeger@pci.uzh.ch [Physikalisch-Chemisches Institut, Universitaet Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland)

    2010-12-09

    Graphical abstract: Protein-surface interactions play a crucial role in a wide field of research areas like biology, biotechnology, or pharmacology. Only recently, it has been shown that not only peptide adsorption represents an important process but also spreading and clustering of adsorbed proteins. By means of classical molecular dynamics, peptide adsorption as well as the dynamics of adsorbed peptides have been investigated in order to gain deeper insight into such processes. The picture shows a snapshot of an adsorbed peptide on a silica surface showing strong direct hydrogen bonding. Research highlights: {yields} Simulation of peptide surface interaction. {yields} Dynamics of hydrogen bond formation and destruction. {yields} Internal flexibility of adsorbed peptides. - Abstract: Protein adsorption and protein surface interactions have become an important research topic in recent years. Very recently, for example, it has been shown that protein clusters can undergo a surface-induced spreading after adsorption. Such phenomena emphasize the need of a more detailed insight into protein-silica interaction at an atomic level. Therefore, we have studied a model system consisting of a short peptide, a silica slab, and water molecules by means of classical molecular dynamics simulations. The study reveals that, besides of electrostatic interactions caused by the chosen charge distribution, the peptide interacts with the silica surface through formation of direct peptide-surface hydrogen bonds as well as indirect peptide-water-surface hydrogen bonds. The number of created hydrogen bonds varies considerably among the simulated structures. The strength of hydrogen bonding determines the mobility of the peptide on the surface and the internal flexibility of the adsorbed peptide.

  9. Nonlinear beam dynamics of accelerators and storage rings. Progress report, June 1985-April 1986

    International Nuclear Information System (INIS)

    Helleman, R.H.G.

    1986-01-01

    Research has concentrated on the stability problems and resonances involved in the two-dimensional beam-beam effect. Of course, the results are applicable also to coupled nonlinear two-dimensional (x,y) accelerator lattices. From a nonlinear dynamics point of view this means that we investigated how to extend existing methods that worked satisfactorily for the one-dimensional beam-beam effect to the higher dimensional world of two-dimensional nonlinear lattices. This requires study of four coupled nonlinear lattice equations (for x, y, p/sub x/,p/sub y/), i.e., study of four-dimensional conservative nonlinear maps. Until our investigation this year, such maps had not yet been studied in nonlinear dynamics. One of the main results is the conclusion that the very successful ''residue'' method to determine stability (of whole regions of orbits) for the one-dimensional beam-beam effect cannot, in its present form, be used for the two- or three-dimensional case. The second main result is that we have been successful in demonstrating and unraveling the complete Period Doubling structure of the resonances in these four-dimensional maps (two-dimensional beam-beam effect), including the most minute resonances. This is essential for an understanding of such maps. In addition, it is the ''self-similarity'' of these resonances which inspires, and guides, most of our efforts in redesigning the residue criterion mentioned above

  10. Understanding the Risk of Chloride Induced Stress Corrosion Cracking of Interim Storage Containers for the Dry Storage of Spent Nuclear Fuel: Evolution of Brine Chemistry on the Container Surface

    International Nuclear Information System (INIS)

    Enos, David; Bryan, Charles R.

    2015-01-01

    Although the susceptibility of austenitic stainless steels to chloride-induced stress corrosion cracking is well known, uncertainties exist in terms of the environmental conditions that exist on the surface of the storage containers. While a diversity of salts is present in atmospheric aerosols, many of these are not stable when placed onto a heated surface. Given that the surface temperature of any container storing spent nuclear fuel will be well above ambient, it is likely that salts deposited on its surface may decompose or degas. To characterize this effect, relevant single and multi-salt mixtures are being evaluated as a function of temperature and relative humidity to establish the rates of degassing, as well as the likely final salt and brine chemistries that will remain on the canister surface.

  11. Understanding the Risk of Chloride Induced Stress Corrosion Cracking of Interim Storage Containers for the Dry Storage of Spent Nuclear Fuel: Evolution of Brine Chemistry on the Container Surface.

    Energy Technology Data Exchange (ETDEWEB)

    Enos, David; Bryan, Charles R.

    2015-10-01

    Although the susceptibility of austenitic stainless steels to chloride-induced stress corrosion cracking is well known, uncertainties exist in terms of the environmental conditions that exist on the surface of the storage containers. While a diversity of salts is present in atmospheric aerosols, many of these are not stable when placed onto a heated surface. Given that the surface temperature of any container storing spent nuclear fuel will be well above ambient, it is likely that salts deposited on its surface may decompose or degas. To characterize this effect, relevant single and multi-salt mixtures are being evaluated as a function of temperature and relative humidity to establish the rates of degassing, as well as the likely final salt and brine chemistries that will remain on the canister surface.

  12. Study on Dynamic Development of Three-dimensional Weld Pool Surface in Stationary GTAW

    Science.gov (United States)

    Huang, Jiankang; He, Jing; He, Xiaoying; Shi, Yu; Fan, Ding

    2018-04-01

    The weld pool contains abundant information about the welding process. In particular, the type of the weld pool surface shape, i. e., convex or concave, is determined by the weld penetration. To detect it, an innovative laser-vision-based sensing method is employed to observe the weld pool surface of the gas tungsten arc welding (GTAW). A low-power laser dots pattern is projected onto the entire weld pool surface. Its reflection is intercepted by a screen and captured by a camera. Then the dynamic development process of the weld pool surface can be detected. By observing and analyzing, the change of the reflected laser dots reflection pattern, for shape of the weld pool surface shape, was found to closely correlate to the penetration of weld pool in the welding process. A mathematical model was proposed to correlate the incident ray, reflected ray, screen and surface of weld pool based on structured laser specular reflection. The dynamic variation of the weld pool surface and its corresponding dots laser pattern were simulated and analyzed. By combining the experimental data and the mathematical analysis, the results show that the pattern of the reflected laser dots pattern is closely correlated to the development of weld pool, such as the weld penetration. The concavity of the pool surface was found to increase rapidly after the surface shape was changed from convex to concave during the stationary GTAW process.

  13. Pell-Sim - dynamic model for forecasting storage and distribution of wood pellets

    International Nuclear Information System (INIS)

    Vinterbaeck, Johan

    2004-01-01

    This study examined the system of wood pellet distribution to residential consumers. The distribution cost for a residential pellet consumer typically represents 30% of the per tonne price and of this share, the inventory cost could be more than 50%. Important administrative activities in physical distribution are forecasting demand and inventory control. One way to improve distribution systems would be to optimise inventory management for pellet distributors. The aim of this study was to propose improvements in pellet distribution management by using tools from systems analysis. The ultimate goal was to present an optimised storage level curve adapted to the mid-Swedish community of Avesta. An internal model for optimising inventory management, Pell-Sim, was constructed, composed of two integrated parts: a simulation unit to forecast residential wood pellet demand and a spreadsheet unit with inventory-related functions. Daily outdoor temperatures basically regulated the simulation unit. An order point system was chosen for reordering. The residential customers of a distribution company were divided into two groups, delivery and collecting customers, which were statistically treated separately. When collecting and delivery customer input inventories were normally distributed in the intervals from 0 to 3500 kg and 6500 kg, respectively, their annual means of total delivery were both about 7000 kg/customer, which was the desired and empirical level. The expected pellet customer orders were negatively correlated to mean daily temperatures, lagging behind about 1 month. Sensitivity analyses showed that monthly results for ordered quantity and total cost were particularly sensitive to ordering and carrying costs. The Pell-Sim programme can easily be adapted for distributors in other geographical regions. (Author)

  14. Pell-Sim - dynamic model for forecasting storage and distribution of wood pellets

    Energy Technology Data Exchange (ETDEWEB)

    Vinterbaeck, Johan [Swedish Univ. of Agricultural Sciences, Dept. of Forest Management and Products, Uppsala (Sweden)

    2004-12-01

    This study examined the system of wood pellet distribution to residential consumers. The distribution cost for a residential pellet consumer typically represents 30% of the per tonne price and of this share, the inventory cost could be more than 50%. Important administrative activities in physical distribution are forecasting demand and inventory control. One way to improve distribution systems would be to optimise inventory management for pellet distributors. The aim of this study was to propose improvements in pellet distribution management by using tools from systems analysis. The ultimate goal was to present an optimised storage level curve adapted to the mid-Swedish community of Avesta. An internal model for optimising inventory management, Pell-Sim, was constructed, composed of two integrated parts: a simulation unit to forecast residential wood pellet demand and a spreadsheet unit with inventory-related functions. Daily outdoor temperatures basically regulated the simulation unit. An order point system was chosen for reordering. The residential customers of a distribution company were divided into two groups, delivery and collecting customers, which were statistically treated separately. When collecting and delivery customer input inventories were normally distributed in the intervals from 0 to 3500 kg and 6500 kg, respectively, their annual means of total delivery were both about 7000 kg/customer, which was the desired and empirical level. The expected pellet customer orders were negatively correlated to mean daily temperatures, lagging behind about 1 month. Sensitivity analyses showed that monthly results for ordered quantity and total cost were particularly sensitive to ordering and carrying costs. The Pell-Sim programme can easily be adapted for distributors in other geographical regions. (Author)

  15. Desorption dynamics of deuterium molecules from the Si(100)-(3×1) dideuteride surface

    OpenAIRE

    Niida, T; Tsurumaki, Hiroshi; Namiki, Akira

    2006-01-01

    We measured polar angle ()-resolved time-of-flight spectra of D2 molecules desorbing from the Si(100)-(3×1) dideuteride surface. The desorbing D2 molecules exhibit a considerable translational heating with mean desorption kinetic energies of 0.25 eV, which is mostly independent of the desorption angles for 0°30°. The observed desorption dynamics of deuterium was discussed along the principle of detailed balance to predict their adsorption dynamics onto the monohydride Si surface.

  16. Dynamic Surface Adaptive Robust Control of Unmanned Marine Vehicles with Disturbance Observer

    Directory of Open Access Journals (Sweden)

    Pengchao Zhang

    2018-01-01

    Full Text Available This paper presents a dynamic surface adaptive robust control method with disturbance observer for unmanned marine vehicles (UMV. It uses adaptive law to estimate and compensate the disturbance observer error. Dynamic surface is introduced to solve the “differential explosion” caused by the virtual control derivation in traditional backstepping method. The final controlled system is proved to be globally uniformly bounded based on Lyapunov stability theory. Simulation results illustrate the effectiveness of the proposed controller, which can realize the three-dimensional trajectory tracking for UMV with the systematic uncertainty and time-varying disturbances.

  17. Surface activation of cyclo olefin polymer by oxygen plasma discharge: a molecular dynamics study

    International Nuclear Information System (INIS)

    Soberon, Felipe

    2014-01-01

    Thermoplastic substrates made of cyclo olefin polymer (COP) are treated with oxygen plasma discharges to introduce polar groups at the surface. This is the first step in the process of surface functionalization of COP substrates used in biosensor devices. A molecular dynamics model of basic COP structure is implemented using the second-generation reactive empirical bond order (REBO) potentials for hydrocarbon–oxygen interactions. The model includes covalent bond and Van der Waals interactions. The bombardment of a COP surface with mono-energetic atomic oxygen ions, energy in the range 1-35 eV, is simulated and reported here. The dynamics of the substrate modification reveals that the substrate top layer is de-hydrogenated and subsequently builds up an oxygen–carbon matrix layer, ∼10 Å thick. Analysis of the modified substrates indicates that surface yield is predominantly peroxide groups. (paper)

  18. Optimizing conjunctive use of surface water and groundwater resources with stochastic dynamic programming

    DEFF Research Database (Denmark)

    Davidsen, Claus; Liu, Suxia; Mo, Xinguo

    2014-01-01

    . A stochastic dynamic programming (SDP) approach is used to minimize the basin-wide total costs arising from water allocations and water curtailments. Dynamic allocation problems with inclusion of groundwater resources proved to be more complex to solve with SDP than pure surface water allocation problems due...... to head-dependent pumping costs. These dynamic pumping costs strongly affect the total costs and can lead to non-convexity of the future cost function. The water user groups (agriculture, industry, domestic) are characterized by inelastic demands and fixed water allocation and water supply curtailment...

  19. Rapid mixing and short storage timescale in the magma dynamics of a steady-state volcano

    Science.gov (United States)

    Petrone, Chiara Maria; Braschi, Eleonora; Francalanci, Lorella; Casalini, Martina; Tommasini, Simone

    2018-06-01

    Steady-state volcanic activity implies equilibrium between the rate of magma replenishment and eruption of compositionally homogeneous magmas, lasting for tens to thousands of years in an open conduit system. The Present-day activity of Stromboli volcano (Aeolian Islands, Southern Italy) has long been recognised as typical of a steady-state volcano, with a shallow magmatic reservoir (highly porphyritic or hp-magma) continuously refilled by more mafic magma (with low phenocryst content or lp-magma) at a constant rate and accompanied by mixing, crystallisation and eruption. Our aim is to clarify the timescale and dynamics of the plumbing system at the establishment of the Present-day steady-state activity (volcanoes.

  20. Energy saving during bulb storage applying modeling with computational fluid dynamics (CFD)

    Energy Technology Data Exchange (ETDEWEB)

    Sapounas, A.A.; Campen, J.B.; Wildschut, J.; Bot, G.P. [Wageningen UR Greenhouse Horticutlure and Applied Plant Research, Wageningen (Netherlands)

    2010-07-01

    Tulip bulbs are stored in ventilated containers to avoid high ethylene concentration between the bulbs. A commercial computational fluid dynamics (CFD) code was used in this study to examine the distribution of air flow between the containers and the potential energy saving by applying simple solutions concerning the design of the air inlet area and the adjustment of the ventilation rate. The variation in container ventilation was calculated to be between 60 and 180 per cent, with 100 per cent being the average flow through the containers. Various improvement measures were examined. The study showed that 7 per cent energy can be saved by smoothing the sharp corners of the entrance channels of the ventilation wall. The most effective and simple improvement was to cover the open top containers. In this case, the variation was between 80 and 120 per cent. The energy saving was about 38 per cent by adjusting the overall ventilation to the container with the minimal acceptable air flow.

  1. Theoretical Studies of the Structure and the Dynamics on Clean and Chemisorbed Metal Surfaces

    Science.gov (United States)

    Yang, Liqiu

    Molecular dynamics (MD) and lattice dynamics (LD) techniques are employed to investigate several phenomena related to the structure and vibrations at metal surfaces. The MD simulations are performed with the many-body interaction potentials obtained using the Embedded-Atom Method (EAM). As specific examples, we present the results for Ag(100) at 300 K and Cu(100) at 150 K, 300 K, and 600 K. The calculated frequencies and polarizations of all surface modes and resonances at the high-symmetry points in the two-dimensional Brillouin zone are in good agreement with available data, as well as, existing lattice dynamics results with force constants obtained from first-principles calculations. Our calculated surface relaxation is also in reasonable agreement with the data. We also test a much simpler lattice dynamics model with nearest neighbor central force interactions, and conclude that it can reproduce the main features of the phonon modes, but only when adjustable surface parameters are used. Additionally, the temperature dependent studies of the phonon line-widths and the mean-square displacement (MSD) of surface atoms are indicative of enhanced surface anharmonicity. On several chemisorbed metal surfaces, for which force constants are not available from first-principles calculations or the EAM, we perform lattice dynamics studies of phonon dispersion curves using simple force-constant models. These studies provide reliable mean-square displacement of surface atoms and can distinguish between possible reconstruction patterns, the results being insensitive to the exact values of the surface parameters. On c(2 times 2)S-Ni(100), it is found that the parallel component of the mean-square displacement for sulfur is around 50% larger than the vertical component, but for the mean-square displacement of oxygen atoms in the system c(2 times 2)O-Ni(100), the opposite is the case. As regards surface reconstruction, for both p(2 times 1)O-Ag(110) and p(2 times 1)O-Ni(110

  2. Sea Surface Temperature Modeling using Radial Basis Function Networks With a Dynamically Weighted Particle Filter

    KAUST Repository

    Ryu, Duchwan

    2013-03-01

    The sea surface temperature (SST) is an important factor of the earth climate system. A deep understanding of SST is essential for climate monitoring and prediction. In general, SST follows a nonlinear pattern in both time and location and can be modeled by a dynamic system which changes with time and location. In this article, we propose a radial basis function network-based dynamic model which is able to catch the nonlinearity of the data and propose to use the dynamically weighted particle filter to estimate the parameters of the dynamic model. We analyze the SST observed in the Caribbean Islands area after a hurricane using the proposed dynamic model. Comparing to the traditional grid-based approach that requires a supercomputer due to its high computational demand, our approach requires much less CPU time and makes real-time forecasting of SST doable on a personal computer. Supplementary materials for this article are available online. © 2013 American Statistical Association.

  3. Modelling and investigation of partial wetting surfaces for drop dynamics using lattice Boltzmann method

    Energy Technology Data Exchange (ETDEWEB)

    Pravinraj, T., E-mail: pravinraj1711@gmail.com; Patrikar, Rajendra

    2017-07-01

    Highlights: • A LBM model on partial wetting surface for droplet dynamics is presented by introducing a simple initial partial wetting boundary condition in SC model. • With our approach one can tune the splitting volume and time by carefully choosing strip width and position. • It is shown that the droplet spreading on chemically heterogeneous surfaces can be controlled not only by Weber number but also by tuning strip width ratio. • The directional transportation of a droplet due to chemical wetting gradient is simulated and analyzed using hybrid thermodynamic-image processing technique. • Microstructure surface and its influence on the directional wetting based transportation of droplet are demonstrated. - Abstract: Partial wetting surfaces and its influence on the droplet movement of micro and nano scale being contemplated for many useful applications. The dynamics of the droplet usually analyzed with a multiphase lattice Boltzmann method (LBM). In this paper, the influence of partial wetting surface on the dynamics of droplet is systematically analyzed for various cases. Splitting of droplets due to chemical gradient of the surface is studied and analyses of splitting time for various widths of the strips for different Weber numbers are computed. With the proposed model one can tune the splitting volume and time by carefully choosing a strip width and droplet position. The droplet spreading on chemically heterogeneous surfaces shows that the spreading can be controlled not only by parameters of Weber number but also by tuning strip width ratio. The transportation of the droplet from hydrophobic surface to hydrophilic surface due to chemical gradient is simulated and analyzed using our hybrid thermodynamic-image processing technique. The results prove that with the progress of time the surface free energy decreases with increase in spreading area. Finally, the transportation of a droplet on microstructure gradient is demonstrated. The model explains

  4. Dynamical properties of tertiarybutylarsine on GaAs(0 0 1) surface

    CERN Document Server

    Ozeki, M; Tanaka, Y

    2002-01-01

    The dynamical properties of tertiarybutylarsine (TBA) was studied on GaAs(0 0 1) surface using a supersonic molecular beam. The temperature and incident energy dependence of the reflected beam revealed a reaction channel of TBA on GaAs surface with a large decrease in the activation energy from 2.7 to 1.8 eV as the incident energy increases from 0.04 to 2.5 eV.

  5. Desorption dynamics of deuterium molecules from the Si(100)-(3x1) dideuteride surface.

    Science.gov (United States)

    Niida, T; Tsurumaki, H; Namiki, A

    2006-01-14

    We measured polar angle (theta)-resolved time-of-flight spectra of D2 molecules desorbing from the Si(100)-(3x1) dideuteride surface. The desorbing D2 molecules exhibit a considerable translational heating with mean desorption kinetic energies of approximately 0.25 eV, which is mostly independent of the desorption angles for 0 degreesdynamics of deuterium was discussed along the principle of detailed balance to predict their adsorption dynamics onto the monohydride Si surface.

  6. Microbial dynamics during industrial rearing, processing, and storage of the tropical house cricket (Gryllodes sigillatus) for human consumption.

    Science.gov (United States)

    Vandeweyer, Dries; Wynants, Enya; Crauwels, Sam; Verreth, Christel; Viaene, Nikolaas; Claes, Johan; Lievens, Bart; Van Campenhout, Leen

    2018-04-06

    In this study, the microbiota during industrial rearing, processing, and storage of the edible tropical house cricket, Gryllodes sigillatus , was investigated. To this end, samples were analyzed of the cricket feed, before feeding as well as taken from the cages, and the crickets during rearing, after harvest, and after processing into frozen, oven-dried, and smoked and subsequently oven-dried end products. Although the feed contained lower microbial numbers than the crickets, both were dominated by the same species-level operational taxonomic units as determined by Illumina Miseq sequencing. They corresponded, among others, to members of Porphyromonadaceae, Fusobacterium , Parabacteroides and Erwinia The harvested crickets contained high microbial numbers, but none of the investigated food pathogens Salmonella spp., Listeria monocytogenes , Bacillus cereus , and coagulase-positive staphylococci. However, some possible mycotoxin-producing fungi were isolated from the crickets. A post-harvest heat treatment, shortly boiling the crickets, reduced microbial numbers, but an endospore load of 2.4 log cfu/g remained. After processing, an increase in microbial counts was observed for dried and smoked plus dried crickets. Additionally, in the smoked plus dried crickets, a high abundance of a Bacillus sp. was observed. Considering the possible occurrence of food-pathogenic species from this genus, it is advised to apply a heat treatment which is sufficient to eliminate spores. Nevertheless, the microbial numbers remained constant over a six-month storage period, frozen (frozen end product) or at ambient temperature (oven-dried and smoked plus dried end products). Importance. The need for sustainable protein sources has led to the emergence of a new food sector, producing and processing edible insects into foods. However, insight into the microbial quality of this new food and into the microbial dynamics during rearing, processing and storage of edible insects is still

  7. Developing a Novel Hydrogen Sponge with Ideal Binding Energy and High Surface Area for Practical Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Chung, T. C. Mike

    2018-04-19

    This Phase I (5 quarters) research project was to examine the validity of a new class of boron-containing polymer (B-polymer) frameworks, serving as the adsorbents for the practical onboard H2 storage applications. Three B-polymer frameworks were synthesized and investigated, which include B-poly(butyenylstyrene) (B-PBS) framework (A), B-poly(phenyldiacetyene) (B-PPDA) framework (B), and B-poly(phenyltriacetylene) (B-PPTA) framework (C). They are 2-D polymer structures with the repeating cyclic units that spontaneously form open morphology and the B-doped (p-type) π-electrons delocalized surfaces. The ideal B-polymer framework shall exhibit open micropores (pore size in the range of 1-1.5nm) with high surface area (>3000 m2/g), and the B-dopants in the conjugated framework shall provide high surface energy for interacting with H2 molecules (an ideal H2 binding energy in the range of 15-25 kJ/mol). The pore size distribution and H2 binding energy were investigated at both Penn State and NREL laboratories. So far, the experimental results show the successful synthesis of B-polymer frameworks with the relatively well-defined planar (2-D) structures. The intrinsically formed porous morphology exhibits a broad pore size distribution (in the range of 0.5-10 nm) with specific surface area (~1000 m2/g). The miss-alignment between 2-D layers may block some micropore channels and limit gas diffusion throughout the entire matrix. In addition, the 2-D planar conjugated structure may also allow free π-electrons delocalization throughout the framework, which significantly reduces the acidity of B-moieties (electron-deficiency).The resulting 2-D B-polymer frameworks only exhibit a small increase of H2 binding energy in the range of 8-9 KJ/mole (quite constant over the whole sorption range).

  8. NASA-VOF2D, 2-D Transient Free Surface Incompressible Fluid Dynamic

    International Nuclear Information System (INIS)

    Torrey, M.D.

    1988-01-01

    1 - Description of program or function: NASA-VOF2D is a two- dimensional, transient, free surface incompressible fluid dynamics program. It allows multiple free surfaces with surface tension and wall adhesion forces and has a partial cell treatment which allows curved boundaries and interior obstacles. 2 - Method of solution: NASA-VOF2D simulates incompressible flows with free surfaces using the volume-of-fluid (VOF) algorithm. This technique is based on the use of donor-acceptor differencing to track the free surface across an Eulerian grid. The complete Navier-Stokes equations in primitive variables for an incompressible fluid are solved by finite differences with surface tension and wall adhesion included. Optionally the pressure equation can be solved by a conjugate residual method rather than the successive over-relaxation (SOR) method

  9. Dynamics of a Rydberg hydrogen atom near a metal surface in the electron-extraction scheme

    Energy Technology Data Exchange (ETDEWEB)

    Iñarrea, Manuel [Área de Física Aplicada, Universidad de La Rioja, Logroño (Spain); Lanchares, Víctor [Departamento de Matemáticas y Computación, Universidad de La Rioja, Logroño, La Rioja (Spain); Palacián, Jesús [Departamento de Ingeniería Matemática e Informática, Universidad Pública de Navarra, Pamplona (Spain); Pascual, Ana I. [Departamento de Matemáticas y Computación, Universidad de La Rioja, Logroño, La Rioja (Spain); Salas, J. Pablo, E-mail: josepablo.salas@unirioja.es [Área de Física Aplicada, Universidad de La Rioja, Logroño (Spain); Yanguas, Patricia [Departamento de Ingeniería Matemática e Informática, Universidad Pública de Navarra, Pamplona (Spain)

    2015-01-23

    We study the classical dynamics of a Rydberg hydrogen atom near a metal surface in the presence of a constant electric field in the electron-extraction situation [1], e.g., when the field attracts the electron to the vacuum. From a dynamical point of view, this field configuration provides a dynamics richer than in the usual ion-extraction scheme, because, depending on the values of field and the atom–surface distance, the atom can be ionized only towards the metal surface, only to the vacuum or to the both sides. The evolution of the phase space structure as a function of the atom–surface distance is explored in the bound regime of the atom. In the high energy regime, the ionization mechanism is also investigated. We find that the classical results of this work are in good agreement with the results obtained in the wave-packet propagation study carried out by So et al. [1]. - Highlights: • We study a classical hydrogen atom near a metal surface plus a electric field. • We explore the phase space structure as a function of the field strength. • We find most of the electronic orbits are oriented along the field direction. • We study the ionization of the atom for several atom–surface distances. • This classical study is in good agreement with the quantum results.

  10. The Role of Electronic Excitations on Chemical Reaction Dynamics at Metal, Semiconductor and Nanoparticle Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Tully, John C. [Yale Univ., New Haven, CT (United States)

    2017-06-10

    Chemical reactions are often facilitated and steered when carried out on solid surfaces, essential for applications such as heterogeneous catalysis, solar energy conversion, corrosion, materials processing, and many others. A critical factor that can determine the rates and pathways of chemical reactions at surfaces is the efficiency and specificity of energy transfer; how fast does energy move around and where does it go? For reactions on insulator surfaces energy transfer generally moves in and out of vibrations of the adsorbed molecule and the underlying substrate. By contrast, on metal surfaces, metallic nanoparticles and semiconductors, another pathway for energy flow opens up, excitation and de-excitation of electrons. This so-called “nonadiabatic” mechanism often dominates the transfer of energy and can directly impact the course of a chemical reaction. Conventional computational methods such as molecular dynamics simulation do not account for this nonadiabatic behavior. The current DOE-BES funded project has focused on developing the underlying theoretical foundation and the computational methodology for the prediction of nonadiabatic chemical reaction dynamics at surfaces. The research has successfully opened up new methodology and new applications for molecular simulation. In particular, over the last three years, the “Electronic Friction” theory, pioneered by the PI, has now been developed into a stable and accurate computational method that is sufficiently practical to allow first principles “on-the-fly” simulation of chemical reaction dynamics at metal surfaces.

  11. Molecular Structure and Dynamics in Thin Water Films at the Silica and Graphite Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Argyris, Dr. Dimitrios [University of Oklahoma; Tummala, Dr. Naga Rajesh [University of Oklahoma; StrioloDr., A [Vanderbilt University; Cole, David R [ORNL

    2008-01-01

    The structure and dynamic properties of interfacial water at the graphite and silica solid surfaces were investigated using molecular dynamics simulations. The effect of surface properties on the characteristics of interfacial water was quantified by computing density profiles, radial distribution functions, surface density distributions, orientation order parameters, and residence and reorientation correlation functions. In brief, our results show that the surface roughness, chemical heterogeneity, and surface heterogeneous charge distribution affect the structural and dynamic properties of the interfacial water molecules, as well as their rate of exchange with bulk water. Most importantly, our results indicate the formation of two distinct water layers at the SiO2 surface covered by a large density of hydroxyl groups. Further analysis of the data suggests a highly confined first layer where the water molecules assume preferential hydrogen-down orientation and a second layer whose behavior and characteristics are highly dependent on those of the first layer through a well-organized hydrogen bond network. The results suggest that water-water interactions, in particular hydrogen bonds, may be largely responsible for macroscopic interfacial properties such as adsorption and contact angle.

  12. Quantum dynamics on potential energy surfaces. Simpler states and simpler dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Keller, Johannes Friedrich

    2015-09-25

    In this dissertation we analyze and simplify wave functions and observables in the context of quantum molecular dynamics. The two main topics we discuss are the structure of Hagedorn wave packets in position and phase space, and semiclassical approximations for the propagation of quantum expectations with nonnegative phase space densities. We provide algorithmic discretizations for these approximations and illustrate their validity and applicability by means of numerical experiments.

  13. Communication: Contrasting effects of glycerol and DMSO on lipid membrane surface hydration dynamics and forces

    Energy Technology Data Exchange (ETDEWEB)

    Schrader, Alex M. [Department of Chemical Engineering, University of California, Santa Barbara, California 93106 (United States); Cheng, Chi-Yuan [Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106 (United States); Israelachvili, Jacob N. [Department of Chemical Engineering, University of California, Santa Barbara, California 93106 (United States); Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106 (United States); Materials Department, University of California, Santa Barbara, California 93106 (United States); Han, Songi [Department of Chemical Engineering, University of California, Santa Barbara, California 93106 (United States); Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106 (United States)

    2016-07-28

    Glycerol and dimethyl sulfoxide (DMSO) are commonly used cryoprotectants in cellular systems, but due to the challenges of measuring the properties of surface-bound solvent, fundamental questions remain regarding the concentration, interactions, and conformation of these solutes at lipid membrane surfaces. We measured the surface water diffusivity at gel-phase dipalmitoylphosphatidylcholine (DPPC) bilayer surfaces in aqueous solutions containing ≤7.5 mol. % of DMSO or glycerol using Overhauser dynamic nuclear polarization. We found that glycerol similarly affects the diffusivity of water near the bilayer surface and that in the bulk solution (within 20%), while DMSO substantially increases the diffusivity of surface water relative to bulk water. We compare these measurements of water dynamics with those of equilibrium forces between DPPC bilayers in the same solvent mixtures. DMSO greatly decreases the range and magnitude of the repulsive forces between the bilayers, whereas glycerol increases it. We propose that the differences in hydrogen bonding capability of the two solutes leads DMSO to dehydrate the lipid head groups, while glycerol affects surface hydration only as much as it affects the bulk water properties. The results suggest that the mechanism of the two most common cryoprotectants must be fundamentally different: in the case of DMSO by decoupling the solvent from the lipid surface, and in the case of glycerol by altering the hydrogen bond structure and intermolecular cohesion of the global solvent, as manifested by increased solvent viscosity.

  14. Molecular dynamics for lateral surface adhesion and peeling behavior of single-walled carbon nanotubes on gold surfaces

    International Nuclear Information System (INIS)

    Huang, Pei-Hsing

    2011-01-01

    Highlights: ► Adhesion and peeling behaviors of SWCNTs are investigated by detailed, fully atomistic MD simulations. ► Adhesion energy of SWCNTs are discussed. ► Dynamical behaviors of SWCNTs in low temperature adhesion are analyzed. ► Adhesion strengths of SWCNTs obtained from MD simulations are compared with the predictions of Hamaker theory and JKR model. - Abstract: Functional gecko-inspired adhesives have attracted a lot of research attention in the last decade. In this work, the lateral surface adhesion and normal peeling-off behavior of single-walled carbon nanotubes (SWCNTs) on gold substrates are investigated by performing detailed, fully atomistic molecular dynamics (MD) simulations. The effects of the diameter and adhered length of CNTs on the adhesive properties were systematically examined. The simulation results indicate that adhesion energies between the SWCNTs and the Au surface varied from 220 to 320 mJ m −2 over the reported chirality range. The adhesion forces on the lateral surface and the tip of the nanotubes obtained from MD simulations agree very well with the predictions of Hamaker theory and Johnson–Kendall–Roberts (JKR) model. The analyses of covalent bonds indicate that the SWCNTs exhibited excellent flexibility and extensibility when adhering at low temperatures (∼100 K). This mechanism substantially increases adhesion time compared to that obtained at higher temperatures (300–700 K), which makes SWCNTs promising for biomimetic adhesives in ultra-low temperature surroundings.

  15. Molecular dynamics for lateral surface adhesion and peeling behavior of single-walled carbon nanotubes on gold surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Pei-Hsing, E-mail: phh@mail.npust.edu.tw [Department of Mechanical Engineering, National Pingtung University of Science and Technology, Pingtung 912, Taiwan (China)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Adhesion and peeling behaviors of SWCNTs are investigated by detailed, fully atomistic MD simulations. Black-Right-Pointing-Pointer Adhesion energy of SWCNTs are discussed. Black-Right-Pointing-Pointer Dynamical behaviors of SWCNTs in low temperature adhesion are analyzed. Black-Right-Pointing-Pointer Adhesion strengths of SWCNTs obtained from MD simulations are compared with the predictions of Hamaker theory and JKR model. - Abstract: Functional gecko-inspired adhesives have attracted a lot of research attention in the last decade. In this work, the lateral surface adhesion and normal peeling-off behavior of single-walled carbon nanotubes (SWCNTs) on gold substrates are investigated by performing detailed, fully atomistic molecular dynamics (MD) simulations. The effects of the diameter and adhered length of CNTs on the adhesive properties were systematically examined. The simulation results indicate that adhesion energies between the SWCNTs and the Au surface varied from 220 to 320 mJ m{sup -2} over the reported chirality range. The adhesion forces on the lateral surface and the tip of the nanotubes obtained from MD simulations agree very well with the predictions of Hamaker theory and Johnson-Kendall-Roberts (JKR) model. The analyses of covalent bonds indicate that the SWCNTs exhibited excellent flexibility and extensibility when adhering at low temperatures ({approx}100 K). This mechanism substantially increases adhesion time compared to that obtained at higher temperatures (300-700 K), which makes SWCNTs promising for biomimetic adhesives in ultra-low temperature surroundings.

  16. Dynamic Fluid Flow and Geomechanical Coupling to Assess the CO2 Storage Integrity in Faulted Structures

    Directory of Open Access Journals (Sweden)

    Baroni A.

    2015-04-01

    Full Text Available The SiteChar research on the Southern Adriatic Sea site focused on the investigation of the geomechanical and hydrodynamic behaviour of the storage complex in the case of CO2 injection in a reservoir consisting of fractured carbonate formations. Special attention was paid to the effects that natural faults and fractures might have on CO2 migration, and the effects that injection might have on the stability of faults. This assessment was originally performed via a hydro-geomechanical one-way coupling which relies on an adequate representation of faults in the model, allowing one to simulate fluid flow along the fault plane and inside faults as well as evolution of the stress state due to CO2 injection. The geological model was populated with petrophysical and geomechanical parameters derived either from laboratory measurements performed on samples from a reservoir analogue, or published literature. Since only sparse data were available, various scenarios were simulated to take into account the uncertainties in the fluid flow and geomechanical properties of the model: the different state of faults (i.e., open or closed and various in situ stress state, commonly named geostatic stresses as the earth’s crust deformation is assumed to be slow regarding the short-term study. Various fluid flow parameters were also considered, although only one set of petrophysical data corresponding to the most realistic ones is considered here. Faults modeled as volumetric elements behave as flow pathways for fluids when they are conductive. The injected CO2 migrates inside and through the Rovesti fault, which is located near the injection well. The fluid flow also induces overpressure in the faults. The overpressure in the Rovesti fault reaches 2.2 MPa while it reaches 4.4 MPa at the bottom hole of the injector. Extending to about 30 km, the pore pressure field reaches the Gondola fault located at 15 km from the injection zone but the overpressure does not exceed

  17. Quantum State-Resolved Collision Dynamics of Nitric Oxide at Ionic Liquid and Molten Metal Surfaces

    Science.gov (United States)

    Zutz, Amelia Marie

    Detailed molecular scale interactions at the gas-liquid interface are explored with quantum state-to-state resolved scattering of a jet-cooled beam of NO(2pi1/2; N = 0) from ionic liquid and molten metal surfaces. The scattered distributions are probed via laser-induced fluorescence methods, which yield rotational and spin-orbit state populations that elucidate the dynamics of energy transfer at the gas-liquid interface. These collision dynamics are explored as a function of incident collision energy, surface temperature, scattering angle, and liquid identity, all of which are found to substantially affect the degree of rotational, electronic and vibrational excitation of NO via collisions at the liquid surface. Rotational distributions observed reveal two distinct scattering pathways, (i) molecules that trap, thermalize and eventually desorb from the surface (trapping-desorption, TD), and (ii) those that undergo prompt recoil (impulsive scattering, IS) prior to complete equilibration with the liquid surface. Thermally desorbing NO molecules are found to have rotational temperatures close to, but slightly cooler than the surface temperature, indicative of rotational dependent sticking probabilities on liquid surfaces. Nitric oxide is a radical with multiple low-lying electronic states that serves as an ideal candidate for exploring nonadiabatic state-changing collision dynamics at the gas-liquid interface, which induce significant excitation from ground (2pi1/2) to excited (2pi 3/2) spin-orbit states. Molecular beam scattering of supersonically cooled NO from hot molten metals (Ga and Au, Ts = 300 - 1400 K) is also explored, which provide preliminary evidence for vibrational excitation of NO mediated by thermally populated electron-hole pairs in the hot, conducting liquid metals. The results highlight the presence of electronically nonadiabatic effects and build toward a more complete characterization of energy transfer dynamics at gas-liquid interfaces.

  18. Friction and Surface Dynamics of Polymers on the Nanoscale by AFM

    NARCIS (Netherlands)

    Schönherr, Holger; Schónherr, Holger; Samori, Paolo; Tocha, E.; Vancso, Gyula J.

    2008-01-01

    In this article the measurement and understanding of friction forces and surface dynamics of polymers on the one hand and the importance of molecular relaxation processes and viscoelasticity in polymers for advanced micro- and nanoscale applications on the other hand are discussed. Particular

  19. The influence of the surface topography on the magnetization dynamics in soft magnetic thin films

    NARCIS (Netherlands)

    Craus, CB; Palasantzas, G; Chezan, AR; De Hosson, JTM; Boerma, DO; Niesen, L

    2005-01-01

    In this work we study the influence of surface roughness on the magnetization dynamics of soft magnetic nanocrystalline Fe-Zr-N thin films deposited (under identical conditions) onto a Si oxide, a thin polymer layer, and a thin Cu layer. The substrate temperature during deposition was approximately

  20. Comparison of molecular dynamics and kinetic modeling of gas-surface interactions

    NARCIS (Netherlands)

    Frezzotti, A.; Gaastra - Nedea, S.V.; Markvoort, A.J.; Spijker, P.; Gibelli, L.

    2008-01-01

    The interaction of a dilute monatomic gas with a solid surface is studied byMolecular Dynamics (MD) simulations and by numerical solutions of a recently proposed kinetic model. Following previous investigations, the heat transport between parallel walls and Couette flow have been adopted as test