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Sample records for cementitious systems multiscale

  1. Multi-Scale Modeling of Cementitious Materials (Briefing Chart)

    DTIC Science & Technology

    2014-08-31

    FEA approach. Voxels are generated for a heterogeneous cementitious material (Type-I cement ) consisting of typical volume fractions of various...for public release; distribution is unlimited. Micromechanics Based Representative Volume Element Modeling of Heterogeneous Cement Paste The views...P.O. Box 12211 Research Triangle Park, NC 27709-2211 cement paste, microstructure, RVE modeling, micromechanics REPORT DOCUMENTATION PAGE 11. SPONSOR

  2. A numerical approach for the design of multiscale fibre-reinforced cementitious composites

    NASA Astrophysics Data System (ADS)

    Montero-Chacón, Francisco; Schlangen, Erik; Cifuentes, Héctor; Medina, Fernando

    2015-10-01

    In the present work, a numerical framework for the design of new multiscale fibre-reinforced cementitious composites is presented. This is accomplished by covering three different length scales, namely the micro-, meso- and macroscale. At the microscale (here defined as ~1 mm), an enhanced fibre-reinforced lattice model is presented for the simulation of strain hardening cementitious composites. On the other hand, the analysis of fibre-reinforced concrete is performed at the mesoscale (~10 mm) by means of a novel lattice-particle model. The main variables in both models are the fibre dimensions (i.e. length and diameter), the fibre volume content and the fibre-matrix bond behaviour. Their contribution to the global mechanical properties is discussed in details. Finally, the structural characterisation of the fibre-reinforced cementitious composites (FRCC) is carried out by means of a hierarchical numerical homogenisation of the material behaviour, integrating the information obtained from lower scales into the macroscale problem (~1 m). The macroscopic response of the resulting material is characterised via three-point bending tests using a continuum damage plastic model. Although the described lattice models can be used independently as design tools in fibre cement-based composites at the micro- or mesoscale, the multiscale procedure described in this paper allows for the development of new types of FRCC by considering the effect of the multiple-scale fibre-reinforcement.

  3. Temporary Cementitious Sealers in Enhanced Geothermal Systems

    SciTech Connect

    Sugama T.; Pyatina, T.; Butcher, T.; Brothers, L.; Bour, D.

    2011-12-31

    Unlike conventional hydrothennal geothermal technology that utilizes hot water as the energy conversion resources tapped from natural hydrothermal reservoir located at {approx}10 km below the ground surface, Enhanced Geothermal System (EGS) must create a hydrothermal reservoir in a hot rock stratum at temperatures {ge}200 C, present in {approx}5 km deep underground by employing hydraulic fracturing. This is the process of initiating and propagating a fracture as well as opening pre-existing fractures in a rock layer. In this operation, a considerable attention is paid to the pre-existing fractures and pressure-generated ones made in the underground foundation during drilling and logging. These fractures in terms of lost circulation zones often cause the wastage of a substantial amount of the circulated water-based drilling fluid or mud. Thus, such lost circulation zones must be plugged by sealing materials, so that the drilling operation can resume and continue. Next, one important consideration is the fact that the sealers must be disintegrated by highly pressured water to reopen the plugged fractures and to promote the propagation of reopened fractures. In response to this need, the objective of this phase I project in FYs 2009-2011 was to develop temporary cementitious fracture sealing materials possessing self-degradable properties generating when {ge} 200 C-heated scalers came in contact with water. At BNL, we formulated two types of non-Portland cementitious systems using inexpensive industrial by-products with pozzolanic properties, such as granulated blast-furnace slag from the steel industries, and fly ashes from coal-combustion power plants. These byproducts were activated by sodium silicate to initiate their pozzolanic reactions, and to create a cemetitious structure. One developed system was sodium silicate alkali-activated slag/Class C fly ash (AASC); the other was sodium silicate alkali-activated slag/Class F fly ash (AASF) as the binder of temper

  4. Multi-scale periodic homogenization of ionic transfer in cementitious materials

    NASA Astrophysics Data System (ADS)

    Bourbatache, K.; Millet, O.; Aït-Mokhtar, A.

    2016-08-01

    A multi-scale periodic homogenization procedure of the ionic transfers in saturated porous media is proposed. An application on a multi-scale porous material was achieved for establishing models describing a ionic transfer from Nernst-Planck-Poisson-Boltzmann system. The first one is obtained by homogenization from the scale of Debye length to the capillary porosity scale, by taking into account the electrical double layer phenomenon. The second one results from another homogenization procedure from the capillary porosity scale to the scale of the material, where the electrical double layer effects are naturally negligible. A numerical parametric study is conducted on three dimensional elementary cells in order to highlight the effects of the electrical double layer on the ionic transfer parameters. Comparisons with existing experimental data are also presented and discussed. The double homogenization procedure gives homogenized diffusion coefficients very close to those obtained experimentally for chlorides ions from electrodiffusion tests carried out in laboratory.

  5. Multi-scale roughness measurement of cementitious materials using different optical profilers and window resizing analysis

    NASA Astrophysics Data System (ADS)

    Montgomery, Paul C.; Salzenstein, Fabien; Gianto, Gianto; Apedo, Komla L.; Serres, Nicolas; Fond, Christophe; Feugeas, Françoise

    2015-05-01

    In the development of new eco-cements for ecologically friendly construction, the porosity, surface structure and chemical nature of the material can influence the bioreceptivity of the surface and the aptitude or not of environmental micro-organisms to form biofilms. Such films are the source of biocontamination that can lead to a degradation in the structural properties over time. Accurate measurement of surface roughness and topography are important to help in the understanding of this interaction. Optical profilers are well adapted to the quantifying of large surface roughness typical of cementitious materials, being more rapid and better able to cope with high roughness compared with stylus and near field probe techniques. But any given surface profiler typically has specific range limits in terms of axial and lateral resolution and field of view, resulting in different roughness values according to the type of optical profiler used. In the present work, unpolished and polished cement paste samples have been measured with two different systems, one using interference microscopy and the other, chromatic confocal sensing. Comparison of the results from both techniques using the method of window re-sizing, more commonly used in tribology, has been used for calculating the average roughness parameters at different scales. The initial results obtained show a successful overlap of the results for the unpolished samples and a slight separation for the polished samples. The validation of the measurements is demonstrated together with a revealing of differences in the measurements on different types of surfaces due to variations in instrument performance.

  6. Multiscale characterization of chemical–mechanical interactions between polymer fibers and cementitious matrix

    SciTech Connect

    Hernández-Cruz, Daniel; Hargis, Craig W.; Bae, Sungchul; Itty, Pierre A.; Meral, Cagla; Dominowski, Jolee; Radler, Michael J.; Kilcoyne, David A.; Monteiro, Paulo J. M.

    2014-04-01

    Together with a series of mechanical tests, the interactions and potential bonding between polymeric fibers and cementitious materials were studied using scanning transmission X-ray microscopy (STXM) and microtomography (lCT). Experimental results showed that these techniques have great potential to characterize the polymer fiber-hydrated cement-paste matrix interface, as well as differentiating the chemistry of the two components of a bi-polymer (hybrid) fiber the polypropylene core and the ethylene acrylic acid copolymer sheath. Similarly, chemical interactions between the hybrid fiber and the cement hydration products were observed, indicating the chemical bonding between the sheath and the hardened cement paste matrix. Microtomography allowed visualization of the performance of the samples, and the distribution and orientation of the two types of fiber in mortar. Beam flexure tests confirmed improved tensile strength of mixes containing hybrid fibers, and expansion bar tests showed similar reductions in expansion for the polypropylene and hybrid fiber mortar bars.

  7. Multiscale Cloud System Modeling

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Moncrieff, Mitchell W.

    2009-01-01

    The central theme of this paper is to describe how cloud system resolving models (CRMs) of grid spacing approximately 1 km have been applied to various important problems in atmospheric science across a wide range of spatial and temporal scales and how these applications relate to other modeling approaches. A long-standing problem concerns the representation of organized precipitating convective cloud systems in weather and climate models. Since CRMs resolve the mesoscale to large scales of motion (i.e., 10 km to global) they explicitly address the cloud system problem. By explicitly representing organized convection, CRMs bypass restrictive assumptions associated with convective parameterization such as the scale gap between cumulus and large-scale motion. Dynamical models provide insight into the physical mechanisms involved with scale interaction and convective organization. Multiscale CRMs simulate convective cloud systems in computational domains up to global and have been applied in place of contemporary convective parameterizations in global models. Multiscale CRMs pose a new challenge for model validation, which is met in an integrated approach involving CRMs, operational prediction systems, observational measurements, and dynamical models in a new international project: the Year of Tropical Convection, which has an emphasis on organized tropical convection and its global effects.

  8. Multiscale Cloud System Modeling

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Moncrieff, Mitchell W.

    2009-01-01

    The central theme of this paper is to describe how cloud system resolving models (CRMs) of grid spacing approximately 1 km have been applied to various important problems in atmospheric science across a wide range of spatial and temporal scales and how these applications relate to other modeling approaches. A long-standing problem concerns the representation of organized precipitating convective cloud systems in weather and climate models. Since CRMs resolve the mesoscale to large scales of motion (i.e., 10 km to global) they explicitly address the cloud system problem. By explicitly representing organized convection, CRMs bypass restrictive assumptions associated with convective parameterization such as the scale gap between cumulus and large-scale motion. Dynamical models provide insight into the physical mechanisms involved with scale interaction and convective organization. Multiscale CRMs simulate convective cloud systems in computational domains up to global and have been applied in place of contemporary convective parameterizations in global models. Multiscale CRMs pose a new challenge for model validation, which is met in an integrated approach involving CRMs, operational prediction systems, observational measurements, and dynamical models in a new international project: the Year of Tropical Convection, which has an emphasis on organized tropical convection and its global effects.

  9. Oxidation of carbon fiber surfaces for use as reinforcement in high-temperature cementitious material systems

    DOEpatents

    Sugama, Toshifumi

    1990-01-01

    The interfacial bond characteristics between carbon fiber and a cement matrix, in high temperature fiber-reinforced cementitious composite systems, can be improved by the oxidative treatment of the fiber surfaces. Compositions and the process for producing the compositions are disclosed.

  10. Oxidation of carbon fiber surfaces for use as reinforcement in high-temperature cementitious material systems

    DOEpatents

    Sugama, Toshifumi.

    1990-05-22

    The interfacial bond characteristics between carbon fiber and a cement matrix, in high temperature fiber-reinforced cementitious composite systems, can be improved by the oxidative treatment of the fiber surfaces. Compositions and the process for producing the compositions are disclosed. 2 figs.

  11. Glass science tutorial: Lecture No. 8, introduction cementitious systems for Low-Level Waste immobilization

    SciTech Connect

    Young, J.F.; Kirkpatrick, R.J.; Mason, T.O.; Brough, A.

    1995-07-01

    This report presents details about cementitious systems for low-level waste immobilization. Topics discussed include: composition and properties of portland cement; hydration properties; microstructure of concrete; pozzolans; slags; zeolites; transport properties; and geological aspects of long-term durability of concrete.

  12. A new system for crack closure of cementitious materials using shrinkable polymers

    SciTech Connect

    Jefferson, Anthony; Joseph, Christopher; Lark, Robert; Isaacs, Ben; Dunn, Simon; Weager, Brendon

    2010-05-15

    This paper presents details of an original crack-closure system for cementitious materials using shrinkable polymer tendons. The system involves the incorporation of unbonded pre-oriented polymer tendons in cementitious beams. Crack closure is achieved by thermally activating the shrinkage mechanism of the restrained polymer tendons after the cement-based material has undergone initial curing. The feasibility of the system is demonstrated in a series of small scale experiments on pre-cracked prismatic mortar specimens. The results from these tests show that, upon activation, the polymer tendon completely closes the preformed macro-cracks and imparts a significant stress across the crack faces. The potential of the system to enhance the natural autogenous crack healing process and generally improve the durability of concrete structures is addressed.

  13. New cementitious system: The case of glass frit

    NASA Astrophysics Data System (ADS)

    Fares, Galal

    Canada ranks as the world's third largest aluminium producer, and more than 80% of its aluminum industry is concentrated in Quebec. However, the spent pot-liner waste produced by the aluminium smelters accumulates with time into a considerable amount threatening the Canadian environment, especially that of Quebec. A new-engineered material, known as glass fit (GF) has been developed through the chemical treatment of such waste. GF shows potential hydraulic and pozzolanic properties. GF has been studied as a binder itself and as a supplementary cementitious material (SCM). The activation of industrial by-products into clinkerless binders is a novel trend that has attracted the attention of many researchers. The activation of GF into binder to produce paste, mortar and concrete was the first aim of this study. Potential activation of GF using different types and combinations of inorganic activators and temperatures of activation was successfully achieved and high strength concretes were obtained. Moreover, mortars with high compressive strength were obtained with well-formulated activators at ambient temperature. On the other hand, the utilization of industrial by-products as a partial replacement for cement in concrete is a widespread practice. As GF contains a high concentration of sodium in its structure, there is a concern as to the effect of sodium content on the development of alkali-silica reaction (ASR) expansion of concrete. Therefore, this study also aimed to investigate the effect of GF sodium content in the enhancement of ASR expansion and to find new synergistic mixtures that can effectively mitigate ASR expansion in the long term. We observed that ASR expansion decreases with the replacement level of GF. Different synergistic diagrams containing known SCM (silica fume, fly ash, and slag) were achieved from which different effective mixtures can effectively alleviate ASR expansion. In conclusion, the use of GF in the manufacture of concrete has great

  14. Thermally conductive cementitious grout for geothermal heat pump systems

    DOEpatents

    Allan, Marita

    2001-01-01

    A thermally conductive cement-sand grout for use with a geothermal heat pump system. The cement sand grout contains cement, silica sand, a superplasticizer, water and optionally bentonite. The present invention also includes a method of filling boreholes used for geothermal heat pump systems with the thermally conductive cement-sand grout. The cement-sand grout has improved thermal conductivity over neat cement and bentonite grouts, which allows shallower bore holes to be used to provide an equivalent heat transfer capacity. In addition, the cement-sand grouts of the present invention also provide improved bond strengths and decreased permeabilities. The cement-sand grouts can also contain blast furnace slag, fly ash, a thermoplastic air entraining agent, latex, a shrinkage reducing admixture, calcium oxide and combinations thereof.

  15. Multiscale Computational Models of Complex Biological Systems

    PubMed Central

    Walpole, Joseph; Papin, Jason A.; Peirce, Shayn M.

    2014-01-01

    Integration of data across spatial, temporal, and functional scales is a primary focus of biomedical engineering efforts. The advent of powerful computing platforms, coupled with quantitative data from high-throughput experimental platforms, has allowed multiscale modeling to expand as a means to more comprehensively investigate biological phenomena in experimentally relevant ways. This review aims to highlight recently published multiscale models of biological systems while using their successes to propose the best practices for future model development. We demonstrate that coupling continuous and discrete systems best captures biological information across spatial scales by selecting modeling techniques that are suited to the task. Further, we suggest how to best leverage these multiscale models to gain insight into biological systems using quantitative, biomedical engineering methods to analyze data in non-intuitive ways. These topics are discussed with a focus on the future of the field, the current challenges encountered, and opportunities yet to be realized. PMID:23642247

  16. Modeling of early age loss of lithium ions from pore solution of cementitious systems treated with lithium nitrate

    SciTech Connect

    Kim, Taehwan Olek, Jan

    2015-01-15

    Addition of lithium nitrate admixture to the fresh concrete mixture helps to minimize potential problems related to alkali-silica reaction. For this admixture to function as an effective ASR control measure, it is imperative that the lithium ions remain in the pore solution. However, it was found that about 50% of the originally added lithium ions are removed from the pore solution during early stages of hydration. This paper revealed that the magnitude of the Li{sup +} ion loss is highly dependent on the concentration of Li{sup +} ions in the pore solution and the hydration rate of the cementitious systems. Using these findings, an empirical model has been developed which can predict the loss of Li{sup +} ions from the pore solution during the hydration period. The proposed model can be used to investigate the effects of mixture parameters on the loss of Li{sup +} ions from the pore solution of cementitious system.

  17. Setup of Extruded Cementitious Hollow Tubes as Containing/Releasing Devices in Self-Healing Systems

    PubMed Central

    Formia, Alessandra; Terranova, Salvatore; Antonaci, Paola; Pugno, Nicola Maria; Tulliani, Jean Marc

    2015-01-01

    The aim of this research is to produce self-healing cementitious composites based on the use of cylindrical capsules containing a repairing agent. Cementitious hollow tubes (CHT) having two different internal diameters (of 2 mm and 7.5 mm) were produced by extrusion and used as containers and releasing devices for cement paste/mortar healing agents. Based on the results of preliminary mechanical tests, sodium silicate was selected as the healing agent. The morphological features of several mix designs used to manufacture the extruded hollow tubes, as well as the coatings applied to increase the durability of both core and shell materials are discussed. Three-point bending tests were performed on samples produced with the addition of the above-mentioned cementitious hollow tubes to verify the self-healing effectiveness of the proposed solution. Promising results were achieved, in particular when tubes with a bigger diameter were used. In this case, a substantial strength and stiffness recovery was observed, even in specimens presenting large cracks (>1 mm). The method is inexpensive and simple to scale up; however, further research is needed in view of a final optimization. PMID:28788038

  18. Setup of Extruded Cementitious Hollow Tubes as Containing/Releasing Devices in Self-Healing Systems.

    PubMed

    Formia, Alessandra; Terranova, Salvatore; Antonaci, Paola; Pugno, Nicola Maria; Tulliani, Jean Marc

    2015-04-21

    The aim of this research is to produce self-healing cementitious composites based on the use of cylindrical capsules containing a repairing agent. Cementitious hollow tubes (CHT) having two different internal diameters (of 2 mm and 7.5 mm) were produced by extrusion and used as containers and releasing devices for cement paste/mortar healing agents. Based on the results of preliminary mechanical tests, sodium silicate was selected as the healing agent. The morphological features of several mix designs used to manufacture the extruded hollow tubes, as well as the coatings applied to increase the durability of both core and shell materials are discussed. Three-point bending tests were performed on samples produced with the addition of the above-mentioned cementitious hollow tubes to verify the self-healing effectiveness of the proposed solution. Promising results were achieved, in particular when tubes with a bigger diameter were used. In this case, a substantial strength and stiffness recovery was observed, even in specimens presenting large cracks (>1 mm). The method is inexpensive and simple to scale up; however, further research is needed in view of a final optimization.

  19. Multi-scale biomedical systems: measurement challenges

    NASA Astrophysics Data System (ADS)

    Summers, R.

    2016-11-01

    Multi-scale biomedical systems are those that represent interactions in materials, sensors, and systems from a holistic perspective. It is possible to view such multi-scale activity using measurement of spatial scale or time scale, though in this paper only the former is considered. The biomedical application paradigm comprises interactions that range from quantum biological phenomena at scales of 10-12 for one individual to epidemiological studies of disease spread in populations that in a pandemic lead to measurement at a scale of 10+7. It is clear that there are measurement challenges at either end of this spatial scale, but those challenges that relate to the use of new technologies that deal with big data and health service delivery at the point of care are also considered. The measurement challenges lead to the use, in many cases, of model-based measurement and the adoption of virtual engineering. It is these measurement challenges that will be uncovered in this paper.

  20. The pyramid system for multiscale raster analysis

    USGS Publications Warehouse

    De Cola, L.; Montagne, N.

    1993-01-01

    Geographical research requires the management and analysis of spatial data at multiple scales. As part of the U.S. Geological Survey's global change research program a software system has been developed that reads raster data (such as an image or digital elevation model) and produces a pyramid of aggregated lattices as well as various measurements of spatial complexity. For a given raster dataset the system uses the pyramid to report: (1) mean, (2) variance, (3) a spatial autocorrelation parameter based on multiscale analysis of variance, and (4) a monofractal scaling parameter based on the analysis of isoline lengths. The system is applied to 1-km digital elevation model (DEM) data for a 256-km2 region of central California, as well as to 64 partitions of the region. PYRAMID, which offers robust descriptions of data complexity, also is used to describe the behavior of topographic aspect with scale. ?? 1993.

  1. Irreversible thermodynamics in multiscale stochastic dynamical systems.

    PubMed

    Santillán, Moisés; Qian, Hong

    2011-04-01

    This work extends the results of a recently developed theory of a rather complete thermodynamic formalism for discrete-state, continuous-time Markov processes with and without detailed balance. We investigate whether and in what way the thermodynamic structure is invariant in a multiscale stochastic system, that is, whether the relations between thermodynamic functions of state and process variables remain unchanged when the system is viewed at different time scales and resolutions. Our results show that the dynamics on a fast time scale contribute an entropic term to the internal energy function u(S)(x) for the slow dynamics. Based on the conditional free energy u(S)(x), we can then treat the slow dynamics as if the fast dynamics is nonexistent. Furthermore, we show that the free energy, which characterizes the spontaneous organization in a system without detailed balance, is invariant with or without the fast dynamics: The fast dynamics is assumed to reach stationarity instantaneously on the slow time scale; it has no effect on the system's free energy. The same cannot be said for the entropy and the internal energy, both of which contain the same contribution from the fast dynamics. We also investigate the consequences of time-scale separation in connection to the concepts of quasi-stationarity and steady adiabaticity introduced in the phenomenological steady-state thermodynamics. ©2011 American Physical Society

  2. Magnetospheric MultiScale (MMS) System Manager

    NASA Technical Reports Server (NTRS)

    Schiff, Conrad; Maher, Francis Alfred; Henely, Sean Philip; Rand, David

    2014-01-01

    The Magnetospheric MultiScale (MMS) mission is an ambitious NASA space science mission in which 4 spacecraft are flown in tight formation about a highly elliptical orbit. Each spacecraft has multiple instruments that measure particle and field compositions in the Earths magnetosphere. By controlling the members relative motion, MMS can distinguish temporal and spatial fluctuations in a way that a single spacecraft cannot.To achieve this control, 2 sets of four maneuvers, distributed evenly across the spacecraft must be performed approximately every 14 days. Performing a single maneuver on an individual spacecraft is usually labor intensive and the complexity becomes clearly increases with four. As a result, the MMS flight dynamics team turned to the System Manager to put the routine or error-prone under machine control freeing the analysts for activities that require human judgment.The System Manager is an expert system that is capable of handling operations activities associated with performing MMS maneuvers. As an expert system, it can work off a known schedule, launching jobs based on a one-time occurrence or on a set reoccurring schedule. It is also able to detect situational changes and use event-driven programming to change schedules, adapt activities, or call for help.

  3. Microphysics in Multi-scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2012-01-01

    Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (1) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model), (2) a regional scale model (a NASA unified weather research and forecast, WRF), (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation, and cloud-land surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model. In this talk, a review of developments and applications of the multi-scale modeling system will be presented. In particular, the microphysics development and its performance for the multi-scale modeling system will be presented.

  4. New methods to quantify the cracking performance of cementitious systems made with internal curing

    NASA Astrophysics Data System (ADS)

    Schlitter, John L.

    The use of high performance concretes that utilize low water-cement ratios have been promoted for use in infrastructure based on their potential to increase durability and service life because they are stronger and less porous. Unfortunately, these benefits are not always realized due to the susceptibility of high performance concrete to undergo early age cracking caused by shrinkage. This problem is widespread and effects federal, state, and local budgets that must maintain or replace deterioration caused by cracking. As a result, methods to reduce or eliminate early age shrinkage cracking have been investigated. Internal curing is one such method in which a prewetted lightweight sand is incorporated into the concrete mixture to provide internal water as the concrete cures. This action can significantly reduce or eliminate shrinkage and in some cases causes a beneficial early age expansion. Standard laboratory tests have been developed to quantify the shrinkage cracking potential of concrete. Unfortunately, many of these tests may not be appropriate for use with internally cured mixtures and only provide limited amounts of information. Most standard tests are not designed to capture the expansive behavior of internally cured mixtures. This thesis describes the design and implementation of two new testing devices that overcome the limitations of current standards. The first device discussed in this thesis is called the dual ring. The dual ring is a testing device that quantifies the early age restrained shrinkage performance of cementitious mixtures. The design of the dual ring is based on the current ASTM C 1581-04 standard test which utilizes one steel ring to restrain a cementitious specimen. The dual ring overcomes two important limitations of the standard test. First, the standard single ring test cannot restrain the expansion that takes place at early ages which is not representative of field conditions. The dual ring incorporates a second restraining ring

  5. Rough Set Approach to Incomplete Multiscale Information System

    PubMed Central

    Yang, Xibei; Qi, Yong; Yu, Dongjun; Yu, Hualong; Song, Xiaoning; Yang, Jingyu

    2014-01-01

    Multiscale information system is a new knowledge representation system for expressing the knowledge with different levels of granulations. In this paper, by considering the unknown values, which can be seen everywhere in real world applications, the incomplete multiscale information system is firstly investigated. The descriptor technique is employed to construct rough sets at different scales for analyzing the hierarchically structured data. The problem of unravelling decision rules at different scales is also addressed. Finally, the reduct descriptors are formulated to simplify decision rules, which can be derived from different scales. Some numerical examples are employed to substantiate the conceptual arguments. PMID:25276852

  6. Multiscale integration schemes for jump-diffusion systems

    SciTech Connect

    Givon, D.; Kevrekidis, I.G.

    2008-12-09

    We study a two-time-scale system of jump-diffusion stochastic differential equations. We analyze a class of multiscale integration methods for these systems, which, in the spirit of [1], consist of a hybridization between a standard solver for the slow components and short runs for the fast dynamics, which are used to estimate the effect that the fast components have on the slow ones. We obtain explicit bounds for the discrepancy between the results of the multiscale integration method and the slow components of the original system.

  7. Numerical solution of multiscale electromagnetic systems

    NASA Astrophysics Data System (ADS)

    Tobon Llano, Luis Eduardo

    The Discontinuous Galerkin time domain (DGTD) method is promising in modeling of realistic multiscale electromagnetic systems. This method defines the basic concept for implementing the communication between multiple domains with different scales. Constructing a DGTD system consists of several careful choices: (a) governing equations; (b) element shape and corresponding basis functions for the spatial discretization of each subdomain; (c) numerical fluxes onto interfaces to bond all subdomains together; and (d) time stepping scheme based on properties of a discretized system. This work present the advances in each one of these steps. First, a unified framework based on the theory of differential forms and the finite element method is used to analyze the discretization of the Maxwell's equations. Based on this study, field intensities (E and H) are associated to 1-forms and curl-conforming basis functions; flux densities (D and B) are associated to 2-forms and divergence-conforming basis functions; and the constitutive relations are defined by Hodge operators. A different approach is the study of numerical dispersion. Semidiscrete analysis is the traditional method, but for high order elements modal analysis is prefered. From these analyses, we conclude that a correct discretization of fields belonging to different p-form (e.g., E and B ) uses basis functions with same order of interpolation; however, different order of interpolation must be used if two fields belong to the same p-form (e.g., E and H). An alternative method to evaluate numerical dispersion based on evaluation of dispersive Hodge operators is also presented. Both dispersion analyses are equivalent and reveal same fundamental results. Eigenvalues, eigenvector and transient results are studied to verify accuracy and computational costs of different schemes. Two different approaches are used for implementing the DG Method. The first is based on E and H fields, which use curl-conforming basis functions

  8. Multi-scale methodology: a key to deciphering systems biology.

    PubMed

    Ye, Xinhao; Chu, Ju; Zhuang, Yinping; Zhang, Siliang

    2005-01-01

    Presently, it is widely accepted complex systems couldn't be comprehended by studying parts in isolation without examining integrative and emergent properties, and system-level understanding thus has become the focus in biological science. However, it should also be noted that common systematic analysis was restricted to large-scale analysis at a certain level, while the facts that the nature of complex systems is their multi-scale structures was usually neglected or ignored. Therefore, this paper described a multi-scale methodology to investigate the nature of biological complexity and prospected this methodology could lead to a promising revolution in current system-level understanding and the integration of molecular biology databases.

  9. Multiscale modeling of integrated CCS systems

    NASA Astrophysics Data System (ADS)

    Alhajaj, Ahmed; Shah, Nilay

    2015-01-01

    The world will continue consuming fossil fuel within the coming decades to meet its growing energy demand; however, this source must be cleaner through implementation of carbon capture, transport and storage (CCTS). This process is complex and involves multiple phases, owned by different operational companies and stakeholders with different business models and regulatory framework. The objective of this work is to develop a multiscale modeling approach to link process models, post-combustion capture plant model and network design models under an optimization framework in order to design and analyse the cost optimal CO2 infrastructure that match CO2 sources and sinks in capacity and time. The network comprises a number of CO2 sources at fixed locations and a number of potential CO2 storage sites. The decisions to be determined include from which sources it is appropriate to capture CO2 and the cost-optimal degree-of-capture (DOC) for a given source and the infrastructural layout of the CO2 transmission network.

  10. Multiscale simulation of a power-cooling system

    NASA Astrophysics Data System (ADS)

    Cerroni, Daniele; Da Vià, Roberto; Manservisi, Sandro; Menghini, Filippo

    2017-07-01

    Multiscale coupling techniques are a useful tool needed to simulate complex and huge physical domains. In particular they can be used when a full 3D simulation cannot be performed due to high computational cost or when one is not interested to accurate 3D details of the whole system. In the present paper we focus our attention on the data exchange between different computational domains and present preliminary results obtained from the coupling of 3D and 2D simulations of a power-cooling system. This multidimensional configuration is coupled with a simple 1D closed loop which overlaps the multidimensional domains. The CFD simulations correct the pressure losses and the temperature field of the 1D solution by using the defective method technique. The multiscale coupling is performed with the aid of the numerical platform SALOME and the MED library. The procedure for the coupling can be also used with different codes to perform complex simulations.

  11. Final Technical Report "Multiscale Simulation Algorithms for Biochemical Systems"

    SciTech Connect

    Petzold, Linda R.

    2012-10-25

    Biochemical systems are inherently multiscale and stochastic. In microscopic systems formed by living cells, the small numbers of reactant molecules can result in dynamical behavior that is discrete and stochastic rather than continuous and deterministic. An analysis tool that respects these dynamical characteristics is the stochastic simulation algorithm (SSA, Gillespie, 1976), a numerical simulation procedure that is essentially exact for chemical systems that are spatially homogeneous or well stirred. Despite recent improvements, as a procedure that simulates every reaction event, the SSA is necessarily inefficient for most realistic problems. There are two main reasons for this, both arising from the multiscale nature of the underlying problem: (1) stiffness, i.e. the presence of multiple timescales, the fastest of which are stable; and (2) the need to include in the simulation both species that are present in relatively small quantities and should be modeled by a discrete stochastic process, and species that are present in larger quantities and are more efficiently modeled by a deterministic differential equation (or at some scale in between). This project has focused on the development of fast and adaptive algorithms, and the fun- damental theory upon which they must be based, for the multiscale simulation of biochemical systems. Areas addressed by this project include: (1) Theoretical and practical foundations for ac- celerated discrete stochastic simulation (tau-leaping); (2) Dealing with stiffness (fast reactions) in an efficient and well-justified manner in discrete stochastic simulation; (3) Development of adaptive multiscale algorithms for spatially homogeneous discrete stochastic simulation; (4) Development of high-performance SSA algorithms.

  12. A Goddard Multi-Scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, W.K.; Anderson, D.; Atlas, R.; Chern, J.; Houser, P.; Hou, A.; Lang, S.; Lau, W.; Peters-Lidard, C.; Kakar, R.; Kumar, S.; Lapenta, W.; Li, X.; Matsui, T.; Rienecker, M.; Shen, B.W.; Shi, J.J.; Simpson, J.; Zeng, X.

    2008-01-01

    Numerical cloud resolving models (CRMs), which are based the non-hydrostatic equations of motion, have been extensively applied to cloud-scale and mesoscale processes during the past four decades. Recent GEWEX Cloud System Study (GCSS) model comparison projects have indicated that CRMs agree with observations in simulating various types of clouds and cloud systems from different geographic locations. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that Numerical Weather Prediction (NWP) and regional scale model can be run in grid size similar to cloud resolving model through nesting technique. Current and future NASA satellite programs can provide cloud, precipitation, aerosol and other data at very fine spatial and temporal scales. It requires a coupled global circulation model (GCM) and cloud-scale model (termed a szrper-parameterization or multi-scale modeling -framework, MMF) to use these satellite data to improve the understanding of the physical processes that are responsible for the variation in global and regional climate and hydrological systems. The use of a GCM will enable global coverage, and the use of a CRM will allow for better and more sophisticated physical parameterization. NASA satellite and field campaign can provide initial conditions as well as validation through utilizing the Earth Satellite simulators. At Goddard, we have developed a multi-scale modeling system with unified physics. The modeling system consists a coupled GCM-CRM (or MMF); a state-of-the-art weather research forecast model (WRF) and a cloud-resolving model (Goddard Cumulus Ensemble model). In these models, the same microphysical schemes (2ICE, several 3ICE), radiation (including explicitly calculated cloud optical properties), and surface models are applied. In addition, a comprehensive unified Earth Satellite

  13. Multivariate and Multiscale Data Assimilation in Terrestrial Systems: A Review

    PubMed Central

    Montzka, Carsten; Pauwels, Valentijn R. N.; Franssen, Harrie-Jan Hendricks; Han, Xujun; Vereecken, Harry

    2012-01-01

    More and more terrestrial observational networks are being established to monitor climatic, hydrological and land-use changes in different regions of the World. In these networks, time series of states and fluxes are recorded in an automated manner, often with a high temporal resolution. These data are important for the understanding of water, energy, and/or matter fluxes, as well as their biological and physical drivers and interactions with and within the terrestrial system. Similarly, the number and accuracy of variables, which can be observed by spaceborne sensors, are increasing. Data assimilation (DA) methods utilize these observations in terrestrial models in order to increase process knowledge as well as to improve forecasts for the system being studied. The widely implemented automation in observing environmental states and fluxes makes an operational computation more and more feasible, and it opens the perspective of short-time forecasts of the state of terrestrial systems. In this paper, we review the state of the art with respect to DA focusing on the joint assimilation of observational data precedents from different spatial scales and different data types. An introduction is given to different DA methods, such as the Ensemble Kalman Filter (EnKF), Particle Filter (PF) and variational methods (3/4D-VAR). In this review, we distinguish between four major DA approaches: (1) univariate single-scale DA (UVSS), which is the approach used in the majority of published DA applications, (2) univariate multiscale DA (UVMS) referring to a methodology which acknowledges that at least some of the assimilated data are measured at a different scale than the computational grid scale, (3) multivariate single-scale DA (MVSS) dealing with the assimilation of at least two different data types, and (4) combined multivariate multiscale DA (MVMS). Finally, we conclude with a discussion on the advantages and disadvantages of the assimilation of multiple data types in a

  14. Multivariate and multiscale data assimilation in terrestrial systems: a review.

    PubMed

    Montzka, Carsten; Pauwels, Valentijn R N; Franssen, Harrie-Jan Hendricks; Han, Xujun; Vereecken, Harry

    2012-11-26

    More and more terrestrial observational networks are being established to monitor climatic, hydrological and land-use changes in different regions of the World. In these networks, time series of states and fluxes are recorded in an automated manner, often with a high temporal resolution. These data are important for the understanding of water, energy, and/or matter fluxes, as well as their biological and physical drivers and interactions with and within the terrestrial system. Similarly, the number and accuracy of variables, which can be observed by spaceborne sensors, are increasing. Data assimilation (DA) methods utilize these observations in terrestrial models in order to increase process knowledge as well as to improve forecasts for the system being studied. The widely implemented automation in observing environmental states and fluxes makes an operational computation more and more feasible, and it opens the perspective of short-time forecasts of the state of terrestrial systems. In this paper, we review the state of the art with respect to DA focusing on the joint assimilation of observational data precedents from different spatial scales and different data types. An introduction is given to different DA methods, such as the Ensemble Kalman Filter (EnKF), Particle Filter (PF) and variational methods (3/4D-VAR). In this review, we distinguish between four major DA approaches: (1) univariate single-scale DA (UVSS), which is the approach used in the majority of published DA applications, (2) univariate multiscale DA (UVMS) referring to a methodology which acknowledges that at least some of the assimilated data are measured at a different scale than the computational grid scale, (3) multivariate single-scale DA (MVSS) dealing with the assimilation of at least two different data types, and (4) combined multivariate multiscale DA (MVMS). Finally, we conclude with a discussion on the advantages and disadvantages of the assimilation of multiple data types in a

  15. Multiscale Systems Modeling of Male Reproductive Tract ...

    EPA Pesticide Factsheets

    The reproductive tract is a complex, integrated organ system with diverse embryology and unique sensitivity to prenatal environmental exposures that disrupt morphoregulatory processes and endocrine signaling. U.S. EPA’s in vitro high-throughput screening (HTS) database (ToxCastDB) was used to profile the bioactivity of 54 chemicals with male developmental consequences across ~800 molecular and cellular features [Leung et al., accepted manuscript]. The in vitro bioactivity on molecular targets could be condensed into 156 gene annotations in a bipartite network. These results highlighted the role of estrogen and androgen signaling pathways in male reproductive tract development, and importantly, broadened the list of molecular targets to include GPCRs, cytochrome-P450s, vascular remodeling proteins, and retinoic acid signaling. A multicellular agent-based model was used to simulate the complex interactions between morphoregulatory, endocrine, and environmental influences during genital tubercle (GT) development. Spatially dynamic signals (e.g., SHH, FGF10, and androgen) were implemented in the model to address differential adhesion, cell motility, proliferation, and apoptosis. Urethral tube closure was an emergent feature of the model that was linked to gender-specific rates of ventral mesenchymal proliferation and urethral plate endodermal apoptosis, both under control of androgen signaling [Leung et al., manuscript in preparation]. A systemic parameter sweep w

  16. Dynamics of a neural system with a multiscale architecture

    PubMed Central

    Breakspear, Michael; Stam, Cornelis J

    2005-01-01

    The architecture of the brain is characterized by a modular organization repeated across a hierarchy of spatial scales—neurons, minicolumns, cortical columns, functional brain regions, and so on. It is important to consider that the processes governing neural dynamics at any given scale are not only determined by the behaviour of other neural structures at that scale, but also by the emergent behaviour of smaller scales, and the constraining influence of activity at larger scales. In this paper, we introduce a theoretical framework for neural systems in which the dynamics are nested within a multiscale architecture. In essence, the dynamics at each scale are determined by a coupled ensemble of nonlinear oscillators, which embody the principle scale-specific neurobiological processes. The dynamics at larger scales are ‘slaved’ to the emergent behaviour of smaller scales through a coupling function that depends on a multiscale wavelet decomposition. The approach is first explicated mathematically. Numerical examples are then given to illustrate phenomena such as between-scale bifurcations, and how synchronization in small-scale structures influences the dynamics in larger structures in an intuitive manner that cannot be captured by existing modelling approaches. A framework for relating the dynamical behaviour of the system to measured observables is presented and further extensions to capture wave phenomena and mode coupling are suggested. PMID:16087448

  17. Multilingual interfaces for parallel coupling in multiphysics and multiscale systems.

    SciTech Connect

    Ong, E. T.; Larson, J. W.; Norris, B.; Jacob, R. L.; Tobis, M.; Steder, M.; Mathematics and Computer Science; Univ. of Wisconsin; Australian National Univ.; Univ. of Chicago

    2007-01-01

    Multiphysics and multiscale simulation systems are emerging as a new grand challenge in computational science, largely because of increased computing power provided by the distributed-memory parallel programming model on commodity clusters. These systems often present a parallel coupling problem in their intercomponent data exchanges. Another potential problem in these coupled systems is language interoperability between their various constituent codes. In anticipation of combined parallel coupling/language interoperability challenges, we have created a set of interlanguage bindings for a successful parallel coupling library, the Model Coupling Toolkit. We describe the method used for automatically generating the bindings using the Babel language interoperability tool, and illustrate with short examples how MCT can be used from the C++ and Python languages. We report preliminary performance reports for the MCT interpolation benchmark. We conclude with a discussion of the significance of this work to the rapid prototyping of large parallel coupled systems.

  18. Ultrafine cementitious grout

    DOEpatents

    Ahrens, Ernst H.

    1999-01-01

    An ultrafine cementitious grout in three particle grades containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 30 wt. % to about 70 wt. % Portland cement; from about 30 wt. % to about 70 wt. % pumice containing at least 70% amorphous silicon dioxide; and from 1.2 wt. % to about 5.0 wt. % superplasticizer. The superplasticizer is dispersed in the mixing water prior to the addition of dry grout and the W/CM ratio is about 0.4 to 1/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 .mu.m in width.

  19. Ultrafine cementitious grout

    DOEpatents

    Ahrens, Ernst H.

    1998-01-01

    An ultrafine cementitious grout having a particle size 90% of which are less than 6 .mu.m in diameter and an average size of about 2.5 .mu.m or less, and preferably 90% of which are less than 5 .mu.m in diameter and an average size of about 2 .mu.m or less containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 40 wt. % to about 50 wt. % Portland cement; from about 50 wt. % to about 60 wt. % pumice containing at least 60% amorphous silicon dioxide; and from 0.1 wt. % to about 1.5 wt. % superplasticizer. The grout is mixed with water in the W/CM ratio of about 0.4-0.6/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 .mu.m in width.

  20. Ultrafine cementitious grout

    SciTech Connect

    Ahrens, E.H.

    1999-10-19

    An ultrafine cementitious grout in three particle grades containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 30 wt. % to about 70 wt. % Portland cement; from about 30 wt. % to about 70 wt. % pumice containing at least 70% amorphous silicon dioxide; and from 1.2 wt. % to about 5.0 wt. % superplasticizer. The superplasticizer is dispersed in the mixing water prior to the addition of dry grout and the W/CM ratio is about 0.4 to 1/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 {mu}m in width.

  1. Multiscale Systems Biology and Physics of Thrombosis under Flow

    PubMed Central

    Flamm, M. H.

    2012-01-01

    Blood clotting under hemodynamic conditions involves numerous multiscale interactions from the molecular scale to macroscopic vessel and systemic circulation scales. Transmission of shear forces to platelet receptors such as GPIbα, P-selectin, α2β1, and α2bβ3 controls adhesion dynamics. These forces also drive membrane tether formation, cellular deformation, and mechanosignaling in blood cells. Blood flow results in red blood cell (RBC) drift towards the center of the vessel along with a near-wall plasma layer enriched with platelets. RBC motions also dramatically enhance platelet dispersion. Trajectories of individual platelets near a thrombotic deposit dictate capture-activation-arrest dynamics as these newly arriving platelets are exposed to chemical gradients of ADP, thromboxane, and thrombin within a micron-scale boundary layer formed around the deposit. If shear forces are sufficiently elevated (> 50 dyne/cm2), the largest polymers of von Willebrand Factor may elongate with concomitant shear-induced platelet activation. Finally, thrombin generation enhances platelet recruitment and clot strength via fibrin polymerization. By combination of coarse-graining, continuum, and stochastic algorithms, the numerical simulation of the growth rate, composition, and occlusive/embolic potential of a thrombus now spans multiscale phenomena. These simulations accommodate particular flow geometries, blood phenotype, pharmacological regimen, and reactive surfaces to help predict disease risk or response to therapy. PMID:22460075

  2. A Goddard Multi-Scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2008-01-01

    A multi-scale modeling system with unified physics has been developed at NASA Goddard Space Flight Center (GSFC). The system consists of an MMF, the coupled NASA Goddard finite-volume GCM (fvGCM) and Goddard Cumulus Ensemble model (GCE, a CRM); the state-of-the-art Weather Research and Forecasting model (WRF) and the stand alone GCE. These models can share the same microphysical schemes, radiation (including explicitly calculated cloud optical properties), and surface models that have been developed, improved and tested for different environments. The following is presented in this report: (1) a brief review of the GCE model and its applications on the impact of aerosols on deep precipitation processes, (2) the Goddard MMF and the major difference between two existing MMFs (CSU MMF and Goddard MMF), and preliminary results (the comparison with traditional GCMs), and (3) a discussion on the Goddard WRF version (its developments and applications).

  3. Multi-Scale Validation of a Nanodiamond Drug Delivery System and Multi-Scale Engineering Education

    ERIC Educational Resources Information Center

    Schwalbe, Michelle Kristin

    2010-01-01

    This dissertation has two primary concerns: (i) evaluating the uncertainty and prediction capabilities of a nanodiamond drug delivery model using Bayesian calibration and bias correction, and (ii) determining conceptual difficulties of multi-scale analysis from an engineering education perspective. A Bayesian uncertainty quantification scheme…

  4. Multi-Scale Validation of a Nanodiamond Drug Delivery System and Multi-Scale Engineering Education

    ERIC Educational Resources Information Center

    Schwalbe, Michelle Kristin

    2010-01-01

    This dissertation has two primary concerns: (i) evaluating the uncertainty and prediction capabilities of a nanodiamond drug delivery model using Bayesian calibration and bias correction, and (ii) determining conceptual difficulties of multi-scale analysis from an engineering education perspective. A Bayesian uncertainty quantification scheme…

  5. Wavelet correlations to reveal multiscale coupling in geophysical systems

    NASA Astrophysics Data System (ADS)

    Casagrande, Erik; Mueller, Brigitte; Miralles, Diego G.; Entekhabi, Dara; Molini, Annalisa

    2015-08-01

    The interactions between climate and the environment are highly complex. Due to this complexity, process-based models are often preferred to estimate the net magnitude and directionality of interactions in the Earth system. However, these models are based on simplifications of our understanding of nature and thus are unavoidably imperfect. Conversely, observation-based data of climatic and environmental variables are becoming increasingly accessible over global scales due to the progress of spaceborne sensing technologies and data-assimilation techniques. Albeit uncertain, these data enable the possibility to start unraveling complex multivariable, multiscale relationships if the appropriate statistical methods are applied. Here we investigate the potential of the wavelet cross-correlation method as a tool for identifying time/frequency-dependent interactions, feedback, and regime shifts in geophysical systems. The ability of wavelet cross-correlation to resolve the fast and slow components of coupled systems is tested on synthetic data of known directionality and then applied to observations to study one of the most critical interactions between land and atmosphere: the coupling between soil moisture and near-ground air temperature. Results show that our method is able to capture the dynamics of the soil moisture-temperature coupling over a wide range of temporal scales (from days to several months) and climatic regimes (from wet to dry) and consistently identify the magnitude and directionality of the coupling. Consequently, wavelet cross-correlations are presented as a promising tool for the study of multiscale interactions, with the potential of being extended to the analysis of causal relationships in the Earth system.

  6. Magnetospheric Multiscale (MMS) Mission Attitude Ground System Design

    NASA Technical Reports Server (NTRS)

    Sedlak, Joseph E.; Superfin, Emil; Raymond, Juan C.

    2011-01-01

    This paper presents an overview of the attitude ground system (AGS) currently under development for the Magnetospheric Multiscale (MMS) mission. The primary responsibilities for the MMS AGS are definitive attitude determination, validation of the onboard attitude filter, and computation of certain parameters needed to improve maneuver performance. For these purposes, the ground support utilities include attitude and rate estimation for validation of the onboard estimates, sensor calibration, inertia tensor calibration, accelerometer bias estimation, center of mass estimation, and production of a definitive attitude history for use by the science teams. Much of the AGS functionality already exists in utilities used at NASA's Goddard Space Flight Center with support heritage from many other missions, but new utilities are being created specifically for the MMS mission, such as for the inertia tensor, accelerometer bias, and center of mass estimation. Algorithms and test results for all the major AGS subsystems are presented here.

  7. Using the PORS Problems to Examine Evolutionary Optimization of Multiscale Systems

    SciTech Connect

    Reinhart, Zachary; Molian, Vaelan; Bryden, Kenneth

    2013-01-01

    Nearly all systems of practical interest are composed of parts assembled across multiple scales. For example, an agrodynamic system is composed of flora and fauna on one scale; soil types, slope, and water runoff on another scale; and management practice and yield on another scale. Or consider an advanced coal-fired power plant: combustion and pollutant formation occurs on one scale, the plant components on another scale, and the overall performance of the power system is measured on another. In spite of this, there are few practical tools for the optimization of multiscale systems. This paper examines multiscale optimization of systems composed of discrete elements using the plus-one-recall-store (PORS) problem as a test case or study problem for multiscale systems. From this study, it is found that by recognizing the constraints and patterns present in discrete multiscale systems, the solution time can be significantly reduced and much more complex problems can be optimized.

  8. Systems biology of asthma and allergic diseases: a multiscale approach.

    PubMed

    Bunyavanich, Supinda; Schadt, Eric E

    2015-01-01

    Systems biology is an approach to understanding living systems that focuses on modeling diverse types of high-dimensional interactions to develop a more comprehensive understanding of complex phenotypes manifested by the system. High-throughput molecular, cellular, and physiologic profiling of populations is coupled with bioinformatic and computational techniques to identify new functional roles for genes, regulatory elements, and metabolites in the context of the molecular networks that define biological processes associated with system physiology. Given the complexity and heterogeneity of asthma and allergic diseases, a systems biology approach is attractive, as it has the potential to model the myriad connections and interdependencies between genetic predisposition, environmental perturbations, regulatory intermediaries, and molecular sequelae that ultimately lead to diverse disease phenotypes and treatment responses across individuals. The increasing availability of high-throughput technologies has enabled system-wide profiling of the genome, transcriptome, epigenome, microbiome, and metabolome, providing fodder for systems biology approaches to examine asthma and allergy at a more holistic level. In this article we review the technologies and approaches for system-wide profiling, as well as their more recent applications to asthma and allergy. We discuss approaches for integrating multiscale data through network analyses and provide perspective on how individually captured health profiles will contribute to more accurate systems biology views of asthma and allergy.

  9. Predictive Multiscale Modeling of Nanocellulose Based Materials and Systems

    NASA Astrophysics Data System (ADS)

    Kovalenko, Andriy

    2014-08-01

    enables rational design of CNC-based bionanocomposite materials and systems. Furthermore, the 3D-RISM-KH based multiscale modeling addresses the effect of hemicellulose and lignin composition on nanoscale forces that control cell wall strength towards overcoming plant biomass recalcitrance. It reveals molecular forces maintaining the cell wall structure and provides directions for genetic modulation of plants and pretreatment design to render biomass more amenable to processing. We envision integrated biomass valorization based on extracting and decomposing the non-cellulosic components to low molecular weight chemicals and utilizing the cellulose microfibrils to make CNC. This is an important alternative to approaches of full conversion of lignocellulose to biofuels that face challenges arising from the deleterious impact of cellulose crystallinity on enzymatic processing.

  10. Ultrafine cementitious grout

    DOEpatents

    Ahrens, E.H.

    1998-07-07

    An ultrafine cementitious grout is described having a particle size 90% of which are less than 6 {micro}m in diameter and an average size of about 2.5 {micro}m or less, and preferably 90% of which are less than 5 {micro}m in diameter and an average size of about 2 {micro}m or less containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 40 wt. % to about 50 wt. % Portland cement; from about 50 wt. % to about 60 wt. % pumice containing at least 60% amorphous silicon dioxide; and from 0.1 wt. % to about 1.5 wt. % superplasticizer. The grout is mixed with water in the W/CM ratio of about 0.4--0.6/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 {micro}m in width. 4 figs.

  11. The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities In Assessing The Degradation Of Cementitious Barriers

    SciTech Connect

    Flach, G. P.; Burns, H. H.; Langton, C.; Smith, F. G. III; Brown, K. G.; Kosson, D. S.; Garrabrants, A. C.; Sarkar, S.; van der Sloot, H.; Meeussen, J. C.L.; Samson, E.; Mallick, P.; Suttora, L.; Esh, D. W.; Fuhrmann, M. J.; Philip, J.

    2013-01-11

    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste and Nuclear Materials Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to 100 years and longer for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox has produced tangible benefits to the DOE Performance Assessment (PA) community. A review of prior DOE PAs has provided a list of potential opportunities for improving cementitious barrier performance predictions through the use of the CBP software tools. These opportunities include: 1) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, 2) prediction of changes in Kd/mobility as a function of time that result from changing pH and redox conditions, 3) concrete degradation from rebar corrosion due to carbonation, 4) early age cracking from drying and/or thermal shrinkage and 5) degradation due to sulfate attack. The CBP has already had opportunity to provide near-term, tangible support to ongoing DOE-EM PAs such as the Savannah River Saltstone Disposal Facility (SDF) by providing a sulfate attack analysis that predicts the extent and damage that sulfate ingress will have on the concrete vaults over extended time (i.e., > 1000 years). This analysis is one of the many technical opportunities in cementitious barrier performance that can be addressed by the DOE-EM sponsored CBP software

  12. Cancer systems biology and modeling: microscopic scale and multiscale approaches.

    PubMed

    Masoudi-Nejad, Ali; Bidkhori, Gholamreza; Hosseini Ashtiani, Saman; Najafi, Ali; Bozorgmehr, Joseph H; Wang, Edwin

    2015-02-01

    Cancer has become known as a complex and systematic disease on macroscopic, mesoscopic and microscopic scales. Systems biology employs state-of-the-art computational theories and high-throughput experimental data to model and simulate complex biological procedures such as cancer, which involves genetic and epigenetic, in addition to intracellular and extracellular complex interaction networks. In this paper, different systems biology modeling techniques such as systems of differential equations, stochastic methods, Boolean networks, Petri nets, cellular automata methods and agent-based systems are concisely discussed. We have compared the mentioned formalisms and tried to address the span of applicability they can bear on emerging cancer modeling and simulation approaches. Different scales of cancer modeling, namely, microscopic, mesoscopic and macroscopic scales are explained followed by an illustration of angiogenesis in microscopic scale of the cancer modeling. Then, the modeling of cancer cell proliferation and survival are examined on a microscopic scale and the modeling of multiscale tumor growth is explained along with its advantages. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Magnetospheric Multiscale Instrument Suite Operations and Data System

    NASA Astrophysics Data System (ADS)

    Baker, D. N.; Riesberg, L.; Pankratz, C. K.; Panneton, R. S.; Giles, B. L.; Wilder, F. D.; Ergun, R. E.

    2016-03-01

    The four Magnetospheric Multiscale (MMS) spacecraft will collect a combined volume of ˜100 gigabits per day of particle and field data. On average, only 4 gigabits of that volume can be transmitted to the ground. To maximize the scientific value of each transmitted data segment, MMS has developed the Science Operations Center (SOC) to manage science operations, instrument operations, and selection, downlink, distribution, and archiving of MMS science data sets. The SOC is managed by the Laboratory for Atmospheric and Space Physics (LASP) in Boulder, Colorado and serves as the primary point of contact for community participation in the mission. MMS instrument teams conduct their operations through the SOC, and utilize the SOC's Science Data Center (SDC) for data management and distribution. The SOC provides a single mission data archive for the housekeeping and science data, calibration data, ephemerides, attitude and other ancillary data needed to support the scientific use and interpretation. All levels of data products will reside at and be publicly disseminated from the SDC. Documentation and metadata describing data products, algorithms, instrument calibrations, validation, and data quality will be provided. Arguably, the most important innovation developed by the SOC is the MMS burst data management and selection system. With nested automation and "Scientist-in-the-Loop" (SITL) processes, these systems are designed to maximize the value of the burst data by prioritizing the data segments selected for transmission to the ground. This paper describes the MMS science operations approach, processes and data systems, including the burst system and the SITL concept.

  14. Magnetospheric Multiscale Instrument Suite Operations and Data System

    NASA Technical Reports Server (NTRS)

    Baker, D. N.; Riesberg, L.; Pankratz, C. K.; Panneton, R. S.; Giles, B. L.; Wilder, F. D.; Ergun, R. E.

    2015-01-01

    The four Magnetospheric Multiscale (MMS) spacecraft will collect a combined volume of approximately 100 gigabits per day of particle and field data. On average, only 4 gigabits of that volume can be transmitted to the ground. To maximize the scientific value of each transmitted data segment, MMS has developed the Science Operations Center (SOC) to manage science operations, instrument operations, and selection, downlink, distribution, and archiving of MMS science data sets. The SOC is managed by the Laboratory for Atmospheric and Space Physics (LASP) in Boulder, Colorado and serves as the primary point of contact for community participation in the mission. MMS instrument teams conduct their operations through the SOC, and utilize the SOC's Science Data Center (SOC) for data management and distribution. The SOC provides a single mission data archive for the housekeeping and science data, calibration data, ephemerides, attitude and other ancillary data needed to support the scientific use and interpretation. All levels of data products will reside at and be publicly disseminated from the SDC. Documentation and metadata describing data products, algorithms, instrument calibrations, validation, and data quality will be provided. Arguably, the most important innovation developed by the SOC is the MMS burst data management and selection system. With nested automation and 'Scientist-in-the-Loop' (SITL) processes, these systems are designed to maximize the value of the burst data by prioritizing the data segments selected for transmission to the ground. This paper describes the MMS science operations approach, processes and data systems, including the burst system and the SITL concept.

  15. Design and application of a generic clinical decision support system for multiscale data.

    PubMed

    Mattila, Jussi; Koikkalainen, Juha; Virkki, Arho; van Gils, Mark; Lötjönen, Jyrki

    2012-01-01

    Medical research and clinical practice are currently being redefined by the constantly increasing amounts of multiscale patient data. New methods are needed to translate them into knowledge that is applicable in healthcare. Multiscale modeling has emerged as a way to describe systems that are the source of experimental data. Usually, a multiscale model is built by combining distinct models of several scales, integrating, e.g., genetic, molecular, structural, and neuropsychological models into a composite representation. We present a novel generic clinical decision support system, which models a patient's disease state statistically from heterogeneous multiscale data. Its goal is to aid in diagnostic work by analyzing all available patient data and highlighting the relevant information to the clinician. The system is evaluated by applying it to several medical datasets and demonstrated by implementing a novel clinical decision support tool for early prediction of Alzheimer's disease.

  16. A Goddard Multi-Scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2010-01-01

    A multi-scale modeling system with unified physics has been developed at NASA Goddard Space Flight Center (GSFC). The system consists of an MMF, the coupled NASA Goddard finite-volume GCM (fvGCM) and Goddard Cumulus Ensemble model (GCE, a CRM); the state-of-the-art Weather Research and Forecasting model (WRF) and the stand alone GCE. These models can share the same microphysical schemes, radiation (including explicitly calculated cloud optical properties), and surface models that have been developed, improved and tested for different environments. In this talk, I will present: (1) A brief review on GCE model and its applications on the impact of the aerosol on deep precipitation processes, (2) The Goddard MMF and the major difference between two existing MMFs (CSU MMF and Goddard MMF), and preliminary results (the comparison with traditional GCMs), and (3) A discussion on the Goddard WRF version (its developments and applications). We are also performing the inline tracer calculation to comprehend the ph ysical processes (i.e., boundary layer and each quadrant in the boundary layer) related to the development and structure of hurricanes and mesoscale convective systems.

  17. A Goddard Multi-Scale Modeling System with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2010-01-01

    A multi-scale modeling system with unified physics has been developed at NASA Goddard Space Flight Center (GSFC). The system consists of an MMF, the coupled NASA Goddard finite-volume GCM (fvGCM) and Goddard Cumulus Ensemble model (GCE, a CRM); the state-of-the-art Weather Research and Forecasting model (WRF) and the stand alone GCE. These models can share the same microphysical schemes, radiation (including explicitly calculated cloud optical properties), and surface models that have been developed, improved and tested for different environments. In this talk, I will present: (1) A brief review on GCE model and its applications on the impact of the aerosol on deep precipitation processes, (2) The Goddard MMF and the major difference between two existing MMFs (CSU MMF and Goddard MMF), and preliminary results (the comparison with traditional GCMs), and (3) A discussion on the Goddard WRF version (its developments and applications). We are also performing the inline tracer calculation to comprehend the physical processes (i.e., boundary layer and each quadrant in the boundary layer) related to the development and structure of hurricanes and mesoscale convective systems. In addition, high - resolution (spatial. 2km, and temporal, I minute) visualization showing the model results will be presented.

  18. Testing multi-scale processing in the auditory system

    PubMed Central

    Teng, Xiangbin; Tian, Xing; Poeppel, David

    2016-01-01

    Natural sounds contain information on multiple timescales, so the auditory system must analyze and integrate acoustic information on those different scales to extract behaviorally relevant information. However, this multi-scale process in the auditory system is not widely investigated in the literature, and existing models of temporal integration are mainly built upon detection or recognition tasks on a single timescale. Here we use a paradigm requiring processing on relatively ‘local’ and ‘global’ scales and provide evidence suggesting that the auditory system extracts fine-detail acoustic information using short temporal windows and uses long temporal windows to abstract global acoustic patterns. Behavioral task performance that requires processing fine-detail information does not improve with longer stimulus length, contrary to predictions of previous temporal integration models such as the multiple-looks and the spectro-temporal excitation pattern model. Moreover, the perceptual construction of putatively ‘unitary’ auditory events requires more than hundreds of milliseconds. These findings support the hypothesis of a dual-scale processing likely implemented in the auditory cortex. PMID:27713546

  19. Software Integration in Multi-scale Simulations: the PUPIL System

    NASA Astrophysics Data System (ADS)

    Torras, J.; Deumens, E.; Trickey, S. B.

    2006-10-01

    The state of the art for computational tools in both computational chemistry and computational materials physics includes many algorithms and functionalities which are implemented again and again. Several projects aim to reduce, eliminate, or avoid this problem. Most such efforts seem to be focused within a particular specialty, either quantum chemistry or materials physics. Multi-scale simulations, by their very nature however, cannot respect that specialization. In simulation of fracture, for example, the energy gradients that drive the molecular dynamics (MD) come from a quantum mechanical treatment that most often derives from quantum chemistry. That “QM” region is linked to a surrounding “CM” region in which potentials yield the forces. The approach therefore requires the integration or at least inter-operation of quantum chemistry and materials physics algorithms. The same problem occurs in “QM/MM” simulations in computational biology. The challenge grows if pattern recognition or other analysis codes of some kind must be used as well. The most common mode of inter-operation is user intervention: codes are modified as needed and data files are managed “by hand” by the user (interactively and via shell scripts). User intervention is however inefficient by nature, difficult to transfer to the community, and prone to error. Some progress (e.g Sethna’s work at Cornell [C.R. Myers et al., Mat. Res. Soc. Symp. Proc., 538(1999) 509, C.-S. Chen et al., Poster presented at the Material Research Society Meeting (2000)]) has been made on using Python scripts to achieve a more efficient level of interoperation. In this communication we present an alternative approach to merging current working packages without the necessity of major recoding and with only a relatively light wrapper interface. The scheme supports communication among the different components required for a given multi-scale calculation and access to the functionalities of those components

  20. Linear theory for filtering nonlinear multiscale systems with model error

    PubMed Central

    Berry, Tyrus; Harlim, John

    2014-01-01

    In this paper, we study filtering of multiscale dynamical systems with model error arising from limitations in resolving the smaller scale processes. In particular, the analysis assumes the availability of continuous-time noisy observations of all components of the slow variables. Mathematically, this paper presents new results on higher order asymptotic expansion of the first two moments of a conditional measure. In particular, we are interested in the application of filtering multiscale problems in which the conditional distribution is defined over the slow variables, given noisy observation of the slow variables alone. From the mathematical analysis, we learn that for a continuous time linear model with Gaussian noise, there exists a unique choice of parameters in a linear reduced model for the slow variables which gives the optimal filtering when only the slow variables are observed. Moreover, these parameters simultaneously give the optimal equilibrium statistical estimates of the underlying system, and as a consequence they can be estimated offline from the equilibrium statistics of the true signal. By examining a nonlinear test model, we show that the linear theory extends in this non-Gaussian, nonlinear configuration as long as we know the optimal stochastic parametrization and the correct observation model. However, when the stochastic parametrization model is inappropriate, parameters chosen for good filter performance may give poor equilibrium statistical estimates and vice versa; this finding is based on analytical and numerical results on our nonlinear test model and the two-layer Lorenz-96 model. Finally, even when the correct stochastic ansatz is given, it is imperative to estimate the parameters simultaneously and to account for the nonlinear feedback of the stochastic parameters into the reduced filter estimates. In numerical experiments on the two-layer Lorenz-96 model, we find that the parameters estimated online, as part of a filtering procedure

  1. Knowledge based system for runtime controlling of multiscale model of ion-exchange solvent extraction

    NASA Astrophysics Data System (ADS)

    Macioł, Piotr; Gotfryd, Leszek; Macioł, Andrzej

    2012-09-01

    The hereby paper concerns the issue of solution of runtime controlling of multiscale model of ion-exchange solvent extraction. It is based on cooperation of a framework applying Agile Multiscale Modeling Methodology (AM3), and the REBIT Knowledge Based System. Ion-exchange solvent extraction has been shortly introduced. Design assumptions of AM3 and theoretical basis of REBIT have been described. Designed workflows and rules for simple laminar/ turbulent flow and extraction processes have been shown.

  2. Intrinsic Multi-Scale Dynamic Behaviors of Complex Financial Systems.

    PubMed

    Ouyang, Fang-Yan; Zheng, Bo; Jiang, Xiong-Fei

    2015-01-01

    The empirical mode decomposition is applied to analyze the intrinsic multi-scale dynamic behaviors of complex financial systems. In this approach, the time series of the price returns of each stock is decomposed into a small number of intrinsic mode functions, which represent the price motion from high frequency to low frequency. These intrinsic mode functions are then grouped into three modes, i.e., the fast mode, medium mode and slow mode. The probability distribution of returns and auto-correlation of volatilities for the fast and medium modes exhibit similar behaviors as those of the full time series, i.e., these characteristics are rather robust in multi time scale. However, the cross-correlation between individual stocks and the return-volatility correlation are time scale dependent. The structure of business sectors is mainly governed by the fast mode when returns are sampled at a couple of days, while by the medium mode when returns are sampled at dozens of days. More importantly, the leverage and anti-leverage effects are dominated by the medium mode.

  3. Systematically improvable multiscale solver for correlated electron systems

    NASA Astrophysics Data System (ADS)

    Kananenka, Alexei A.; Gull, Emanuel; Zgid, Dominika

    2015-03-01

    The development of numerical methods capable of simulating realistic materials with strongly correlated electrons, with controllable errors, is a central challenge in quantum many-body physics. Here we describe a framework for a general multiscale method based on embedding a self-energy of a strongly correlated subsystem into a self-energy generated by a method able to treat large weakly correlated systems approximately. As an example, we present the embedding of an exact diagonalization self-energy into a self-energy generated from self-consistent second-order perturbation theory. Using a quantum impurity model, generated from a cluster dynamical mean field approximation to the two-dimensional Hubbard model, as a benchmark, we illustrate that our method allows us to obtain accurate results at a fraction of the cost of typical Monte Carlo calculations. We test the method in multiple regimes of interaction strengths and dopings of the model. The general embedding framework we present avoids difficulties such as double counting corrections, frequency-dependent interactions, or vertex functions. As it is solely formulated at the level of the single-particle Green's function, it provides a promising route for the simulation of realistic materials that are currently difficult to study with other methods.

  4. Intrinsic Multi-Scale Dynamic Behaviors of Complex Financial Systems

    PubMed Central

    Ouyang, Fang-Yan; Zheng, Bo; Jiang, Xiong-Fei

    2015-01-01

    The empirical mode decomposition is applied to analyze the intrinsic multi-scale dynamic behaviors of complex financial systems. In this approach, the time series of the price returns of each stock is decomposed into a small number of intrinsic mode functions, which represent the price motion from high frequency to low frequency. These intrinsic mode functions are then grouped into three modes, i.e., the fast mode, medium mode and slow mode. The probability distribution of returns and auto-correlation of volatilities for the fast and medium modes exhibit similar behaviors as those of the full time series, i.e., these characteristics are rather robust in multi time scale. However, the cross-correlation between individual stocks and the return-volatility correlation are time scale dependent. The structure of business sectors is mainly governed by the fast mode when returns are sampled at a couple of days, while by the medium mode when returns are sampled at dozens of days. More importantly, the leverage and anti-leverage effects are dominated by the medium mode. PMID:26427063

  5. Toward multiscale modelings of grain-fluid systems

    NASA Astrophysics Data System (ADS)

    Chareyre, Bruno; Yuan, Chao; Montella, Eduard P.; Salager, Simon

    2017-06-01

    Computationally efficient methods have been developed for simulating partially saturated granular materials in the pendular regime. In contrast, one hardly avoid expensive direct resolutions of 2-phase fluid dynamics problem for mixed pendular-funicular situations or even saturated regimes. Following previous developments for single-phase flow, a pore-network approach of the coupling problems is described. The geometry and movements of phases and interfaces are described on the basis of a tetrahedrization of the pore space, introducing elementary objects such as bridge, meniscus, pore body and pore throat, together with local rules of evolution. As firmly established local rules are still missing on some aspects (entry capillary pressure and pore-scale pressure-saturation relations, forces on the grains, or kinetics of transfers in mixed situations) a multi-scale numerical framework is introduced, enhancing the pore-network approach with the help of direct simulations. Small subsets of a granular system are extracted, in which multiphase scenario are solved using the Lattice-Boltzman method (LBM). In turns, a global problem is assembled and solved at the network scale, as illustrated by a simulated primary drainage.

  6. CEMENTITIOUS BARRIERS PARTNERSHIP ACCOMPLISHMENTS AND RELEVANCE TO THE DOE COMPLEX

    SciTech Connect

    Burns, H.; Langton, C.; Flach, G.; Kosson, D.

    2010-11-15

    The Cementitious Barriers Partnership (CBP) was initiated to reduce risk and uncertainties in the performance assessments that directly impact U.S. Department of Energy (DOE) environmental cleanup and closure programs. The CBP is supported by the DOE Office of Environmental Management (DOE-EM) and has been specifically addressing the following critical EM program needs: (i) the long-term performance of cementitious barriers and materials in nuclear waste disposal facilities and (ii) increased understanding of contaminant transport behavior within cementitious barrier systems to support the development and deployment of adequate closure technologies. To accomplish this, the CBP has two initiatives: (1) an experimental initiative to increase understanding of changes in cementitious materials over long times (> 1000 years) over changing conditions and (2) a modeling initiative to enhance and integrate a set of computational tools validated by laboratory and field experimental data to improve understanding and prediction of the long-term performance of cementitious barriers and waste forms used in nuclear applications. In FY10, the CBP developed the initial phase of an integrated modeling tool that would serve as a screening tool which could help in making decisions concerning disposal and tank closure. The CBP experimental programs are underway to validate this tool and provide increased understanding of how CM changes over time and under changing conditions. These initial CBP products that will eventually be enhanced are anticipated to reduce the uncertainties of current methodologies for assessing cementitious barrier performance and increase the consistency and transparency of the DOE assessment process. These tools have application to low activity waste forms, high level waste tank closure, D&D and entombment of major nuclear facilities, landfill waste acceptance criteria, and in-situ grouting and immobilization of vadose zone contamination. This paper summarizes

  7. Self-degradable Cementitious Sealing Materials

    SciTech Connect

    Sugama, T.; Butcher, T., Lance Brothers, Bour, D.

    2010-10-01

    A self-degradable alkali-activated cementitious material consisting of a sodium silicate activator, slag, Class C fly ash, and sodium carboxymethyl cellulose (CMC) additive was formulated as one dry mix component, and we evaluated its potential in laboratory for use as a temporary sealing material for Enhanced Geothermal System (EGS) wells. The self-degradation of alkali-activated cementitious material (AACM) occurred, when AACM heated at temperatures of {ge}200 C came in contact with water. We interpreted the mechanism of this water-initiated self-degradation as resulting from the in-situ exothermic reactions between the reactants yielded from the dissolution of the non-reacted or partially reacted sodium silicate activator and the thermal degradation of the CMC. The magnitude of self-degradation depended on the CMC content; its effective content in promoting degradation was {ge}0.7%. In contrast, no self-degradation was observed from CMC-modified Class G well cement. For 200 C-autoclaved AACMs without CMC, followed by heating at temperatures up to 300 C, they had a compressive strength ranging from 5982 to 4945 psi, which is {approx}3.5-fold higher than that of the commercial Class G well cement; the initial- and final-setting times of this AACM slurry at 85 C were {approx}60 and {approx}90 min. Two well-formed crystalline hydration phases, 1.1 nm tobermorite and calcium silicate hydrate (I), were responsible for developing this excellent high compressive strength. Although CMC is an attractive, as a degradation-promoting additive, its addition to both the AACM and the Class G well cement altered some properties of original cementitious materials; among those were an extending their setting times, an increasing their porosity, and lowering their compressive strength. Nevertheless, a 0.7% CMC-modified AACM as self-degradable cementitious material displayed the following properties before its breakdown by water; {approx}120 min initial- and {approx}180 min final

  8. Tuneable resolution as a systems biology approach for multi-scale, multi-compartment computational models.

    PubMed

    Kirschner, Denise E; Hunt, C Anthony; Marino, Simeone; Fallahi-Sichani, Mohammad; Linderman, Jennifer J

    2014-01-01

    The use of multi-scale mathematical and computational models to study complex biological processes is becoming increasingly productive. Multi-scale models span a range of spatial and/or temporal scales and can encompass multi-compartment (e.g., multi-organ) models. Modeling advances are enabling virtual experiments to explore and answer questions that are problematic to address in the wet-lab. Wet-lab experimental technologies now allow scientists to observe, measure, record, and analyze experiments focusing on different system aspects at a variety of biological scales. We need the technical ability to mirror that same flexibility in virtual experiments using multi-scale models. Here we present a new approach, tuneable resolution, which can begin providing that flexibility. Tuneable resolution involves fine- or coarse-graining existing multi-scale models at the user's discretion, allowing adjustment of the level of resolution specific to a question, an experiment, or a scale of interest. Tuneable resolution expands options for revising and validating mechanistic multi-scale models, can extend the longevity of multi-scale models, and may increase computational efficiency. The tuneable resolution approach can be applied to many model types, including differential equation, agent-based, and hybrid models. We demonstrate our tuneable resolution ideas with examples relevant to infectious disease modeling, illustrating key principles at work.

  9. Multiscale Eulerian Model Within NCEP's National Environmental Modeling System

    NASA Astrophysics Data System (ADS)

    Janjic, Z.; Black, T.; Vasic, R.; Rogers, E.; Dimego, G.

    2010-12-01

    The unified Non-hydrostatic Multi-scale Model on the B grid (NMMB) is being developed at NCEP as a part of the National Environmental Modeling System (NEMS). The finite-volume horizontal differencing employed in the model preserves important properties of differential operators and conserves a variety of basic and derived dynamical and quadratic quantities. Among these, conservation of energy and enstrophy improves the accuracy of nonlinear dynamics. The nonhydrostatic dynamics were formulated in such a way as to avoid overspecification. In the global limit, “across the pole” polar boundary conditions are used, and the polar filter selectively slows down the wave components that would otherwise propagate faster in the zonal direction than the fastest wave propagating in the meridional direction. The physical package of the model has been developed from the standard NCEP’s WRF NMM physics. A global forecasting system based on the NMMB was run for more than a year in order to test and tune the model, and in particular, to examine its potential for medium range weather forecasting. The system was initialized and verified using the analyses of NCEP’s Global Forecasting System (GFS). The skill of the large scale medium range forecasts produced by the system has been comparable to that of other major medium range forecasting systems. The computational efficiency of the model on parallel computers has been competitive with that of other major global systems. Interestingly, even though the NMMB and GFS were starting from the same analyses, the skill of the two individual medium range forecasts was often disparate. When one model produced a bad forecast, the forecast from the other model could be quite good. Such behavior appears potentially advantageous for application of the two models for ensemble forecasting. On the mesoscales, the NMMB is planned to replace the WRF NMM in operations as the North American Model (NAM), and in a number of nested high resolution

  10. Method for the production of cementitious compositions and aggregate derivatives from said compositions

    DOEpatents

    Minnick, L. John

    1981-01-01

    Method for the production of cementitious compositions and aggregate derivatives of said compositions, and cementitious compositions and aggregates produced by said method, wherein fluidized bed combustion residue and pozzolanic material, such as pulverized coal combustion system fly ash, are incorporated in a cementitious mix. The mix is cast into desired shape and cured. If desired, the shape may then be crushed so as to result in a fluidized bed combustion residue-fly ash aggregate material or the shape may be used by itself.

  11. Modeling and simulation of high dimensional stochastic multiscale PDE systems at the exascale

    SciTech Connect

    Zabaras, Nicolas J.

    2016-11-08

    Predictive Modeling of multiscale and Multiphysics systems requires accurate data driven characterization of the input uncertainties, and understanding of how they propagate across scales and alter the final solution. This project develops a rigorous mathematical framework and scalable uncertainty quantification algorithms to efficiently construct realistic low dimensional input models, and surrogate low complexity systems for the analysis, design, and control of physical systems represented by multiscale stochastic PDEs. The work can be applied to many areas including physical and biological processes, from climate modeling to systems biology.

  12. Analysis of Graphite-Reinforced Cementitious Composites

    NASA Technical Reports Server (NTRS)

    Vaughan, R. E.

    2002-01-01

    Strategically embedding graphite meshes in a compliant cementitious matrix produces a composite material with relatively high tension and compressive properties as compared to steel-reinforced structures fabricated from a standard concrete mix. Although these composite systems are somewhat similar, the methods used to analyze steel-reinforced composites often fail to characterize the behavior of their more advanced graphite-reinforced counterparts. This Technical Memorandum describes some of the analytical methods being developed to determine the deflections and stresses in graphite-reinforced cementitious composites. It is initially demonstrated that the standard transform section method fails to provide accurate results when the elastic moduli ratio exceeds 20. An alternate approach is formulated by using the rule of mixtures to determine a set of effective material properties for the composite. Tensile tests are conducted on composite samples to verify this approach. When the effective material properties are used to characterize the deflections of composite beams subjected to pure bending, an excellent agreement is obtained. Laminated composite plate theory is investigated as a means for analyzing even more complex composites, consisting of multiple graphite layers oriented in different directions. In this case, composite beams are analyzed using the laminated composite plate theory with material properties established from tensile tests. Then, finite element modeling is used to verify the results. Considering the complexity of the samples, a very good agreement is obtained.

  13. A multi-scale approach for macromolecular systems

    NASA Astrophysics Data System (ADS)

    Matysiak, Silvina

    Understanding biomolecular dynamics at different time and length scales is key to solving major problems in molecular biology and physical-chemistry. Because of the multiple scales that intrinsically coexist in biological macromolecules, the field has evolved through different paths, each focusing on different fixed resolutions. This thesis focuses on developing realistic models to describe complex biomolecular land-scapes at the mesoscale level, and a procedure to bridge different levels of molecular description for liquid water. Toward this goal, we have proposed a realistic coarse-grained protein model and a technique to incorporate experimental data into the model to examine the long time-scale phenomenon of protein folding/misfolding. We have shown that simulations with this simplified protein representation can be used as a predictive tool for misfolding and aggregation of proteins. Moreover, we have developed a coarse-grained model and an analytical theory to study another long time-scale phenomenon in biology: the translocation of DNA and RNA through nanopores. We have shown that our approach to the translocation process reproduces quantitatively, for the first time, all the experimentally observed trends and scaling behaviour, and provides insight into the different regimes present in the system. Modeling explicit water is crucial for realistic biomolecular simulations, but is typically not computationally feasible. To overcome the computational impasse, we have proposed a coarse-grained water model that can reproduce remarkably well the behaviour of liquid water at physiological conditions, and a spatially adaptive procedure to change the molecular resolution of water on-the-fly from a coarse-grained to an all-atom representation. This adaptive multi-scale approach bridges the gap between the time and length scales accessible to simulations without losing atomistic detail on physically relevant regions.

  14. REFERENCE CASES FOR USE IN THE CEMENTITIOUS BARRIERS PARTNERSHIP

    SciTech Connect

    Langton, C

    2009-01-06

    The Cementitious Barriers Project (CBP) is a multidisciplinary cross cutting project initiated by the US Department of Energy (DOE) to develop a reasonable and credible set of tools to improve understanding and prediction of the structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. The period of performance is >100 years for operating facilities and > 1000 years for waste management. The CBP has defined a set of reference cases to provide the following functions: (1) a common set of system configurations to illustrate the methods and tools developed by the CBP, (2) a common basis for evaluating methodology for uncertainty characterization, (3) a common set of cases to develop a complete set of parameter and changes in parameters as a function of time and changing conditions, and (4) a basis for experiments and model validation, and (5) a basis for improving conceptual models and reducing model uncertainties. These reference cases include the following two reference disposal units and a reference storage unit: (1) a cementitious low activity waste form in a reinforced concrete disposal vault, (2) a concrete vault containing a steel high-level waste tank filled with grout (closed high-level waste tank), and (3) a spent nuclear fuel basin during operation. Each case provides a different set of desired performance characteristics and interfaces between materials and with the environment. Examples of concretes, grout fills and a cementitious waste form are identified for the relevant reference case configurations.

  15. Multiscale asymmetric orthogonal wavelet kernel for linear programming support vector learning and nonlinear dynamic systems identification.

    PubMed

    Lu, Zhao; Sun, Jing; Butts, Kenneth

    2014-05-01

    Support vector regression for approximating nonlinear dynamic systems is more delicate than the approximation of indicator functions in support vector classification, particularly for systems that involve multitudes of time scales in their sampled data. The kernel used for support vector learning determines the class of functions from which a support vector machine can draw its solution, and the choice of kernel significantly influences the performance of a support vector machine. In this paper, to bridge the gap between wavelet multiresolution analysis and kernel learning, the closed-form orthogonal wavelet is exploited to construct new multiscale asymmetric orthogonal wavelet kernels for linear programming support vector learning. The closed-form multiscale orthogonal wavelet kernel provides a systematic framework to implement multiscale kernel learning via dyadic dilations and also enables us to represent complex nonlinear dynamics effectively. To demonstrate the superiority of the proposed multiscale wavelet kernel in identifying complex nonlinear dynamic systems, two case studies are presented that aim at building parallel models on benchmark datasets. The development of parallel models that address the long-term/mid-term prediction issue is more intricate and challenging than the identification of series-parallel models where only one-step ahead prediction is required. Simulation results illustrate the effectiveness of the proposed multiscale kernel learning.

  16. Multiscale modeling in nanostructures: Physical and biological systems

    NASA Astrophysics Data System (ADS)

    Dearden, Albert Karcz

    With the advent of more powerful computer systems, theoretical modeling of nanoscale systems has quickly become a vital part of scientific research in a multitude of disciplines. From the understanding of semiconductor devices to describing the mechanistic details of protein interactions, theoretical studies on systems of various scales have provided great insight into how nature behaves in each scenario. While at a macroscopic level the differences between biological and non-biological systems are apparent, the underlying principles that dictate their behavior are quite similar. Indeed, modeling these two distinct classes of systems have similar challenges. In both cases, the system sizes typically correspond to nanometer length scales and due to the lack of periodicity in the system, one needs to study a relatively larger number of atoms in simulations in order to represent their behavior. Nonetheless, systems that are much smaller than what exists in experiment may be used to describe specific properties of interest, such as how system stability scales with varying size or describing a reaction process of a large biological structure through the modeling of only the reaction site and not the entire protein. Thus, it is important to be able to correctly and efficiently model various systems at multiple scales in order to provide proper insight and understanding so models and tools developed in one area could be applied to another discipline. Indeed, lessons learned during the process are quite valuable for the general scheme of multiscale modeling in materials. To facilitate this, we have investigated two separate cases involving the efficient use of multiscale modeling through ab initio density functional theory calculations. For the first half of this work, we investigate the effect of size on the net magnetization of zero dimensional graphene based structures with differing edge states. Currently, we have shown that for zigzag edged triangular graphene

  17. Industrial process system assessment: bridging process engineering and life cycle assessment through multiscale modeling.

    EPA Science Inventory

    The Industrial Process System Assessment (IPSA) methodology is a multiple step allocation approach for connecting information from the production line level up to the facility level and vice versa using a multiscale model of process systems. The allocation procedure assigns inpu...

  18. Industrial process system assessment: bridging process engineering and life cycle assessment through multiscale modeling.

    EPA Science Inventory

    The Industrial Process System Assessment (IPSA) methodology is a multiple step allocation approach for connecting information from the production line level up to the facility level and vice versa using a multiscale model of process systems. The allocation procedure assigns inpu...

  19. Multiscale characterisation of geological materials through complex systems

    NASA Astrophysics Data System (ADS)

    Tordesillas, A.; Walker, D. M.; Ando, E.; Viggiani, C.

    2012-12-01

    Understanding the fundamental mechanisms underpinning the nucleation, propagation, and arrest of shear zones in geological materials has broad implications for planetary science, earthquake and plate tectonics and deep-Earth energy production, to name a few examples. Such mechanisms are inherently multiscale in space and time. Here we use complex systems techniques to characterise the evolution of shear zones in Hostun and Caicos Ooid sand under triaxial compression, using x-ray micro computed tomography measurements of particle kinematics and interparticle contacts. Observational data on the evolution of individual grain contacts allows the construction of representative contact networks resplendent in topological motifs, especially the stable 3-cycles, formed by three grains in mutual contact. The lifespans of such cycles can be tracked and the special subset of persistent 3-cycles surviving the deformation from the onset of loading can be shown to exhibit spatial clustering at multiple scales, thus pinpointing the spatial and temporal boundaries of shear zones. More abstract complex networks built from relationships between individual grain kinematics rather than physical grain contacts can also provide a wealth of information. In particular, a study of network communities in these kinematical networks helps to uncover a spatial length scale that remains essentially invariant throughout loading and is consistent with the observed shear band thickness. Moreover, community borders in and around the band delineate the band boundaries. A ranking of the complex network measure of closeness centrality of nodes reveals the collection of grains where the persistent shear band ultimately develops. Communities, length scales and centrality measures all depend on shortest path measures and thus we can interpret information in these networks spreads the fastest to and from those nodes corresponding to the grains in the region of strain localisation. This trend, whereby a

  20. Inclined Fiber Pullout from a Cementitious Matrix: A Numerical Study.

    PubMed

    Zhang, Hui; Yu, Rena C

    2016-09-26

    It is well known that fibers improve the performance of cementitious composites by acting as bridging ligaments in cracks. Such bridging behavior is often studied through fiber pullout tests. The relation between the pullout force vs. slip end displacement is characteristic of the fiber-matrix interface. However, such a relation varies significantly with the fiber inclination angle. In the current work, we establish a numerical model to simulate the entire pullout process by explicitly representing the fiber, matrix and the interface for arbitrary fiber orientations. Cohesive elements endorsed with mixed-mode fracture capacities are implemented to represent the bond-slip behavior at the interface. Contact elements with Coulomb's friction are placed at the interface to simulate frictional contact. The bond-slip behavior is first calibrated through pull-out curves for fibers aligned with the loading direction, then validated against experimental results for steel fibers oriented at 30 ∘ and 60 ∘ . Parametric studies are then performed to explore the influences of both material properties (fiber yield strength, matrix tensile strength, interfacial bond) and geometric factors (fiber diameter, embedment length and inclination angle) on the overall pullout behavior, in particular on the maximum pullout load. The proposed methodology provides the necessary pull-out curves for a fiber oriented at a given angle for multi-scale models to study fracture in fiber-reinforced cementitious materials. The novelty lies in its capacity to capture the entire pullout process for a fiber with an arbitrary inclination angle.

  1. Dynamic fracture behaviour in fibre-reinforced cementitious composites

    NASA Astrophysics Data System (ADS)

    Yu, Rena C.; Cifuentes, Héctor; Rivero, Ignacio; Ruiz, Gonzalo; Zhang, Xiaoxin

    2016-08-01

    The object of this work is to simulate the dynamic fracture propagation in fibre-reinforced cementitious composites, in particular, in steel fibre reinforced concrete (SFRC). Beams loaded in a three-point bend configuration through a drop-weight impact device are considered. A single cohesive crack is assumed to propagate at the middle section; the opening of this crack is governed by a rate-dependent cohesive law; the fibres around the fracture plane are explicitly represented through truss elements. The fibre pull-out behaviour is depicted by an equivalent constitutive law, which is obtained from an analytical load-slip curve. The obtained load-displacement curves and crack propagation velocities are compared with their experimental counterparts. The good agreement with experimental data testifies to the feasibility of the proposed methodology and paves the way to its application in a multi-scale framework.

  2. ONE-ATMOSPHERE DYNAMICS DESCRIPTION IN THE MODELS-3 COMMUNITY MULTI-SCALE QUALITY (CMAQ) MODELING SYSTEM

    EPA Science Inventory

    This paper proposes a general procedure to link meteorological data with air quality models, such as U.S. EPA's Models-3 Community Multi-scale Air Quality (CMAQ) modeling system. CMAQ is intended to be used for studying multi-scale (urban and regional) and multi-pollutant (ozon...

  3. ONE-ATMOSPHERE DYNAMICS DESCRIPTION IN THE MODELS-3 COMMUNITY MULTI-SCALE QUALITY (CMAQ) MODELING SYSTEM

    EPA Science Inventory

    This paper proposes a general procedure to link meteorological data with air quality models, such as U.S. EPA's Models-3 Community Multi-scale Air Quality (CMAQ) modeling system. CMAQ is intended to be used for studying multi-scale (urban and regional) and multi-pollutant (ozon...

  4. Incremental Testing of the Community Multiscale Air Quality (CMAQ) Modeling System Version 4.7

    EPA Science Inventory

    This paper describes the scientific and structural updates to the latest release of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7 (v4.7) and points the reader to additional resources for further details. The model updates were evaluated relative to obse...

  5. Description and evaluation of the Community Multiscale Air Quality (CMAQ) modeling system version 5.1

    EPA Science Inventory

    The Community Multiscale Air Quality (CMAQ) model is a comprehensive multipollutant air quality modeling system developed and maintained by the US Environmental Protection Agency's (EPA) Office of Research and Development (ORD). Recently, version 5.1 of the CMAQ model (v5.1) was ...

  6. A multi-scale sensing and diagnosis system combining accelerometers and gyroscopes for bridge health monitoring

    NASA Astrophysics Data System (ADS)

    Sung, S. H.; Park, J. W.; Nagayama, T.; Jung, H. J.

    2014-01-01

    This paper presents a multi-scale sensing and diagnosis system combining accelerometers and gyroscopes for bridge health monitoring. Since the damage metric estimated from acceleration measurement is insensitive to damage near the hinged support of a bridge, the damage diagnosis performance is limited near the support region. However, the performance can be improved by using two or more complementary data measured from multi-scale sensing. To more effectively diagnose the integrity of an overall bridge structure, angular velocity is complementary to acceleration, because of its high sensitivity to damage near the hinged support. This study proposes a multi-scale sensing and diagnosis system for bridge health monitoring based on a two-step approach. First, the damage diagnosis based on acceleration measurement is performed on the whole structure by using deflection estimated by modal flexibility. Next, the angular-velocity-based damage diagnosis is additionally carried out to localize missed damage by the acceleration-based approach near the hinged support. For validating the feasibility of the proposed system, a series of numerical and experimental studies on a simply supported beam model was performed. It was found that the multiple damages (one is near the center and another is near the support) can be successfully localized by the proposed multi-scale sensing and diagnosis system, while the damage near the support was missed by a conventional damage metric estimated from acceleration measurements.

  7. Morpheus: a user-friendly modeling environment for multiscale and multicellular systems biology.

    PubMed

    Starruß, Jörn; de Back, Walter; Brusch, Lutz; Deutsch, Andreas

    2014-05-01

    Morpheus is a modeling environment for the simulation and integration of cell-based models with ordinary differential equations and reaction-diffusion systems. It allows rapid development of multiscale models in biological terms and mathematical expressions rather than programming code. Its graphical user interface supports the entire workflow from model construction and simulation to visualization, archiving and batch processing.

  8. Using Multi-Scale Modeling Systems and Satellite Data to Study the Precipitation Processes

    NASA Technical Reports Server (NTRS)

    Tao, Wei--Kuo; Chern, J.; Lamg, S.; Matsui, T.; Shen, B.; Zeng, X.; Shi, R.

    2010-01-01

    In recent years, exponentially increasing computer power extended Cloud Resolving Model (CRM) integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 sq km in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale models can be run in grid size similar to cloud resolving models through nesting technique. Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (1) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model). (2) a regional scale model (a NASA unified weather research and forecast, W8F). (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation and cloud-land surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model. In this talk, a review of developments and applications of the multi-scale modeling system will be presented. In particular, the results from using multi-scale modeling systems to study the interactions between clouds, precipitation, and aerosols will be presented. Also how to use the multi-satellite simulator to improve precipitation processes will be discussed.

  9. Microphysics in the Multi-Scale Modeling Systems with Unified Physics

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Chern, J.; Lamg, S.; Matsui, T.; Shen, B.; Zeng, X.; Shi, R.

    2011-01-01

    In recent years, exponentially increasing computer power has extended Cloud Resolving Model (CRM) integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 km2 in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale model can be run in grid size similar to cloud resolving model through nesting technique. Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (l) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model), (2) a regional scale model (a NASA unified weather research and forecast, WRF), (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation, and cloud-surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model. In this talk, the microphysics developments of the multi-scale modeling system will be presented. In particular, the results from using multi-scale modeling system to study the heavy precipitation processes will be presented.

  10. Using Multi-Scale Modeling Systems to Study the Precipitation Processes

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2010-01-01

    In recent years, exponentially increasing computer power has extended Cloud Resolving Model (CRM) integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 km2 in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale model can be run in grid size similar to cloud resolving model through nesting technique. Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (1) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model), (2) a regional scale model (a NASA unified weather research and forecast, WRF), (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation, and cloud-land surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model. In this talk, a review of developments and applications of the multi-scale modeling system will be presented. In particular, the results from using multi-scale modeling system to study the interactions between clouds, precipitation, and aerosols will be presented. Also how to use of the multi-satellite simulator to improve precipitation processes will be discussed.

  11. Using Multi-Scale Modeling Systems to Study the Precipitation Processes

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2010-01-01

    In recent years, exponentially increasing computer power has extended Cloud Resolving Model (CRM) integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 km2 in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale model can be run in grid size similar to cloud resolving model through nesting technique. Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (1) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model), (2) a regional scale model (a NASA unified weather research and forecast, WRF), (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation, and cloud-land surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model. In this talk, a review of developments and applications of the multi-scale modeling system will be presented. In particular, the results from using multi-scale modeling system to study the interactions between clouds, precipitation, and aerosols will be presented. Also how to use of the multi-satellite simulator to improve precipitation processes will be discussed.

  12. Using Multi-Scale Modeling Systems and Satellite Data to Study the Precipitation Processes

    NASA Technical Reports Server (NTRS)

    Tao, Wei--Kuo; Chern, J.; Lamg, S.; Matsui, T.; Shen, B.; Zeng, X.; Shi, R.

    2010-01-01

    In recent years, exponentially increasing computer power extended Cloud Resolving Model (CRM) integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 sq km in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale models can be run in grid size similar to cloud resolving models through nesting technique. Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (1) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model). (2) a regional scale model (a NASA unified weather research and forecast, W8F). (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation and cloud-land surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model. In this talk, a review of developments and applications of the multi-scale modeling system will be presented. In particular, the results from using multi-scale modeling systems to study the interactions between clouds, precipitation, and aerosols will be presented. Also how to use the multi-satellite simulator to improve precipitation processes will be discussed.

  13. Human visual system-based multi-scale tools with biomedical and security applications

    NASA Astrophysics Data System (ADS)

    Nercessian, Shahan

    Multi-scale transforms have been shown to be invaluable tools for image processing. The effectiveness of consequently formulated multi-scale algorithms have practically made them de facto standards for realizing solutions for a broad range of image processing problems. Multi-scale formulations of transforms and algorithms are motivated by the ability of the human visual system (HVS) to extract edge structures at their different scales. Image processing algorithms, consequently, have been developed which alter multi-transform coefficients of images for various means. However, the multi-scale contrasts as defined by these schemes generally not consistent with many other relevant HVS phenomena. Upon reviewing relevant HVS characteristics, new tools which are consistent with these features are presented. Accordingly, new image enhancement, image de-noising, and image fusion algorithms which make use of HVS-inspired multi-scale tools are presented as contributions to each of these fields. In this context, the aim of the presented algorithms is two-fold: The intention is to both consider new multi-scale solutions, as well as to formulate them using perceptually-driven mathematical constructs based on HVS characteristics. In the context of image enhancement, a new set of multi-scale image enhancement algorithms are presented which are able to simultaneously provide both local and global enhancements within a direct enhancement framework. For the purpose of image de-noising, a multi-scale formulation of the non-local-means de-noising algorithm is developed which is shown to both visually and quantitatively outperform existing de-noising approaches. Many algorithms to achieve image fusion based on the presented transforms are presented. One set of algorithms is based on a Parameterized Logarithmic Image Processing model, while another is based on an adaptive similarity-based weighting scheme. The interdependence between the different algorithms considered in this

  14. Tuneable resolution as a systems biology approach for multi-scale, multi-compartment computational models

    PubMed Central

    Kirschner, Denise E; Hunt, C Anthony; Marino, Simeone; Fallahi-Sichani, Mohammad; Linderman, Jennifer J

    2014-01-01

    The use of multi-scale mathematical and computational models to study complex biological processes is becoming increasingly productive. Multi-scale models span a range of spatial and/or temporal scales and can encompass multi-compartment (e.g., multi-organ) models. Modeling advances are enabling virtual experiments to explore and answer questions that are problematic to address in the wet-lab. Wet-lab experimental technologies now allow scientists to observe, measure, record, and analyze experiments focusing on different system aspects at a variety of biological scales. We need the technical ability to mirror that same flexibility in virtual experiments using multi-scale models. Here we present a new approach, tuneable resolution, which can begin providing that flexibility. Tuneable resolution involves fine- or coarse-graining existing multi-scale models at the user's discretion, allowing adjustment of the level of resolution specific to a question, an experiment, or a scale of interest. Tuneable resolution expands options for revising and validating mechanistic multi-scale models, can extend the longevity of multi-scale models, and may increase computational efficiency. The tuneable resolution approach can be applied to many model types, including differential equation, agent-based, and hybrid models. We demonstrate our tuneable resolution ideas with examples relevant to infectious disease modeling, illustrating key principles at work. WIREs Syst Biol Med 2014, 6:225–245. doi:10.1002/wsbm.1270 How to cite this article: WIREs Syst Biol Med 2014, 6:289–309. doi:10.1002/wsbm.1270 PMID:24810243

  15. Magnetospheric Multiscale (MMS) Mission Attitude Ground System Design

    NASA Technical Reports Server (NTRS)

    Sedlak, Joseph E.; Superfin, Emil; Raymond, Juan C.

    2010-01-01

    This paper describes the attitude ground system (AGS) design to be used for support of the Magnetospheric MultiScale (MMS) mission. The AGS exists as one component of the mission operations control center. It has responsibility for validating the onboard attitude and accelerometer bias estimates, calibrating the attitude sensors and the spacecraft inertia tensor, and generating a definitive attitude history for use by the science teams. NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Maryland is responsible for developing the MMS spacecraft, for the overall management of the MMS mission, and for mission operations. MMS is scheduled for launch in 2014 for a planned two-year mission. The MMS mission consists of four identical spacecraft flying in a tetrahedral formation in an eccentric Earth orbit. The relatively tight formation, ranging from 10 to 400 km, will provide coordinated observations giving insight into small-scale magnetic field reconnection processes. By varying the size of the tetrahedron and the orbital semi-major axis and eccentricity, and making use of the changing solar phase, this geometry allows for the study of both bow shock and magnetotail plasma physics, including acceleration, reconnection, and turbulence. The mission divides into two phases for science; these phases will have orbit dimensions of 1.2 x 12 Earth radii in the first phase and 1.2x25 Earth radii in the second in order to study the dayside magnetopause and the nightside magnetotail, respectively. The orbital periods are roughly one day and three days for the two mission phases. Each of the four MMS spacecraft will be spin stabilized at 3 revolutions per minute (rpm), with the spin axis oriented near the ecliptic north pole but tipped approximately 2.5 deg towards the Sun line. The main body of each spacecraft will be an eight-sided platform with diameter of 3.4 m and height of 1.2 m. Several booms are attached to this central core: two axial booms of 14.9 m length, two

  16. Efficient Integration of Coupled Electrical-Chemical Systems in Multiscale Neuronal Simulations

    PubMed Central

    Brocke, Ekaterina; Bhalla, Upinder S.; Djurfeldt, Mikael; Hellgren Kotaleski, Jeanette; Hanke, Michael

    2016-01-01

    Multiscale modeling and simulations in neuroscience is gaining scientific attention due to its growing importance and unexplored capabilities. For instance, it can help to acquire better understanding of biological phenomena that have important features at multiple scales of time and space. This includes synaptic plasticity, memory formation and modulation, homeostasis. There are several ways to organize multiscale simulations depending on the scientific problem and the system to be modeled. One of the possibilities is to simulate different components of a multiscale system simultaneously and exchange data when required. The latter may become a challenging task for several reasons. First, the components of a multiscale system usually span different spatial and temporal scales, such that rigorous analysis of possible coupling solutions is required. Then, the components can be defined by different mathematical formalisms. For certain classes of problems a number of coupling mechanisms have been proposed and successfully used. However, a strict mathematical theory is missing in many cases. Recent work in the field has not so far investigated artifacts that may arise during coupled integration of different approximation methods. Moreover, in neuroscience, the coupling of widely used numerical fixed step size solvers may lead to unexpected inefficiency. In this paper we address the question of possible numerical artifacts that can arise during the integration of a coupled system. We develop an efficient strategy to couple the components comprising a multiscale test problem in neuroscience. We introduce an efficient coupling method based on the second-order backward differentiation formula (BDF2) numerical approximation. The method uses an adaptive step size integration with an error estimation proposed by Skelboe (2000). The method shows a significant advantage over conventional fixed step size solvers used in neuroscience for similar problems. We explore different

  17. Efficient Integration of Coupled Electrical-Chemical Systems in Multiscale Neuronal Simulations.

    PubMed

    Brocke, Ekaterina; Bhalla, Upinder S; Djurfeldt, Mikael; Hellgren Kotaleski, Jeanette; Hanke, Michael

    2016-01-01

    Multiscale modeling and simulations in neuroscience is gaining scientific attention due to its growing importance and unexplored capabilities. For instance, it can help to acquire better understanding of biological phenomena that have important features at multiple scales of time and space. This includes synaptic plasticity, memory formation and modulation, homeostasis. There are several ways to organize multiscale simulations depending on the scientific problem and the system to be modeled. One of the possibilities is to simulate different components of a multiscale system simultaneously and exchange data when required. The latter may become a challenging task for several reasons. First, the components of a multiscale system usually span different spatial and temporal scales, such that rigorous analysis of possible coupling solutions is required. Then, the components can be defined by different mathematical formalisms. For certain classes of problems a number of coupling mechanisms have been proposed and successfully used. However, a strict mathematical theory is missing in many cases. Recent work in the field has not so far investigated artifacts that may arise during coupled integration of different approximation methods. Moreover, in neuroscience, the coupling of widely used numerical fixed step size solvers may lead to unexpected inefficiency. In this paper we address the question of possible numerical artifacts that can arise during the integration of a coupled system. We develop an efficient strategy to couple the components comprising a multiscale test problem in neuroscience. We introduce an efficient coupling method based on the second-order backward differentiation formula (BDF2) numerical approximation. The method uses an adaptive step size integration with an error estimation proposed by Skelboe (2000). The method shows a significant advantage over conventional fixed step size solvers used in neuroscience for similar problems. We explore different

  18. A multiscale dataset for understanding complex eco-hydrological processes in a heterogeneous oasis system

    NASA Astrophysics Data System (ADS)

    Li, Xin; Liu, Shaomin; Xiao, Qin; Ma, Mingguo; Jin, Rui; Che, Tao; Wang, Weizhen; Hu, Xiaoli; Xu, Ziwei; Wen, Jianguang; Wang, Liangxu

    2017-06-01

    We introduce a multiscale dataset obtained from Heihe Watershed Allied Telemetry Experimental Research (HiWATER) in an oasis-desert area in 2012. Upscaling of eco-hydrological processes on a heterogeneous surface is a grand challenge. Progress in this field is hindered by the poor availability of multiscale observations. HiWATER is an experiment designed to address this challenge through instrumentation on hierarchically nested scales to obtain multiscale and multidisciplinary data. The HiWATER observation system consists of a flux observation matrix of eddy covariance towers, large aperture scintillometers, and automatic meteorological stations; an eco-hydrological sensor network of soil moisture and leaf area index; hyper-resolution airborne remote sensing using LiDAR, imaging spectrometer, multi-angle thermal imager, and L-band microwave radiometer; and synchronical ground measurements of vegetation dynamics, and photosynthesis processes. All observational data were carefully quality controlled throughout sensor calibration, data collection, data processing, and datasets generation. The data are freely available at figshare and the Cold and Arid Regions Science Data Centre. The data should be useful for elucidating multiscale eco-hydrological processes and developing upscaling methods.

  19. A multiscale dataset for understanding complex eco-hydrological processes in a heterogeneous oasis system

    PubMed Central

    Li, Xin; Liu, Shaomin; Xiao, Qin; Ma, Mingguo; Jin, Rui; Che, Tao; Wang, Weizhen; Hu, Xiaoli; Xu, Ziwei; Wen, Jianguang; Wang, Liangxu

    2017-01-01

    We introduce a multiscale dataset obtained from Heihe Watershed Allied Telemetry Experimental Research (HiWATER) in an oasis-desert area in 2012. Upscaling of eco-hydrological processes on a heterogeneous surface is a grand challenge. Progress in this field is hindered by the poor availability of multiscale observations. HiWATER is an experiment designed to address this challenge through instrumentation on hierarchically nested scales to obtain multiscale and multidisciplinary data. The HiWATER observation system consists of a flux observation matrix of eddy covariance towers, large aperture scintillometers, and automatic meteorological stations; an eco-hydrological sensor network of soil moisture and leaf area index; hyper-resolution airborne remote sensing using LiDAR, imaging spectrometer, multi-angle thermal imager, and L-band microwave radiometer; and synchronical ground measurements of vegetation dynamics, and photosynthesis processes. All observational data were carefully quality controlled throughout sensor calibration, data collection, data processing, and datasets generation. The data are freely available at figshare and the Cold and Arid Regions Science Data Centre. The data should be useful for elucidating multiscale eco-hydrological processes and developing upscaling methods. PMID:28654086

  20. Anatomy and Physiology of Multiscale Modeling and Simulation in Systems Medicine.

    PubMed

    Mizeranschi, Alexandru; Groen, Derek; Borgdorff, Joris; Hoekstra, Alfons G; Chopard, Bastien; Dubitzky, Werner

    2016-01-01

    Systems medicine is the application of systems biology concepts, methods, and tools to medical research and practice. It aims to integrate data and knowledge from different disciplines into biomedical models and simulations for the understanding, prevention, cure, and management of complex diseases. Complex diseases arise from the interactions among disease-influencing factors across multiple levels of biological organization from the environment to molecules. To tackle the enormous challenges posed by complex diseases, we need a modeling and simulation framework capable of capturing and integrating information originating from multiple spatiotemporal and organizational scales. Multiscale modeling and simulation in systems medicine is an emerging methodology and discipline that has already demonstrated its potential in becoming this framework. The aim of this chapter is to present some of the main concepts, requirements, and challenges of multiscale modeling and simulation in systems medicine.

  1. Alteration of fractured cementitious materials

    SciTech Connect

    Sugiyama, Daisuke Fujita, Tomonari; Chida, Taiji; Tsukamoto, Masaki

    2007-08-15

    The alteration of cement materials in a fractured repository was investigated by experimental and modelling techniques to predict the long-term evolution of a cementitious repository for the safety assessment of radioactive waste disposal. A flow-through experiment with an artificially fractured cement column sample was carried out, and the evolution of a chemical composition in discharged water and the distribution of mineral components in a solid matrix, which was dominated by the dissolution of portlandite and calcium-silicate hydrate (C-S-H), were observed. A coupling transport and chemical equilibrium calculation code, which includes a thermodynamic incongruent dissolution model of C-S-H, was developed to predict the alteration of the fractured cement materials. The advection transport of a component in a solution within a crack and the diffusion of a component in a solid matrix were modelled in the calculations. With the proposed model, the possible alteration of cement materials along a crack was described.

  2. Multi-Scale Modeling of a Graphite-Epoxy-Nanotube System

    NASA Technical Reports Server (NTRS)

    Frankland, S. J. V.; Riddick, J. C.; Gates, T. S.

    2005-01-01

    A multi-scale method is utilized to determine some of the constitutive properties of a three component graphite-epoxy-nanotube system. This system is of interest because carbon nanotubes have been proposed as stiffening and toughening agents in the interlaminar regions of carbon fiber/epoxy laminates. The multi-scale method uses molecular dynamics simulation and equivalent-continuum modeling to compute three of the elastic constants of the graphite-epoxy-nanotube system: C11, C22, and C33. The 1-direction is along the nanotube axis, and the graphene sheets lie in the 1-2 plane. It was found that the C11 is only 4% larger than the C22. The nanotube therefore does have a small, but positive effect on the constitutive properties in the interlaminar region.

  3. Multi-Scale Modeling of a Graphite-Epoxy-Nanotube System

    NASA Technical Reports Server (NTRS)

    Frankland, S. J. V.; Riddick, J. C.; Gates, T. S.

    2005-01-01

    A multi-scale method is utilized to determine some of the constitutive properties of a three component graphite-epoxy-nanotube system. This system is of interest because carbon nanotubes have been proposed as stiffening and toughening agents in the interlaminar regions of carbon fiber/epoxy laminates. The multi-scale method uses molecular dynamics simulation and equivalent-continuum modeling to compute three of the elastic constants of the graphite-epoxy-nanotube system: C11, C22, and C33. The 1-direction is along the nanotube axis, and the graphene sheets lie in the 1-2 plane. It was found that the C11 is only 4% larger than the C22. The nanotube therefore does have a small, but positive effect on the constitutive properties in the interlaminar region.

  4. The Multiscale Systems Immunology project: software for cell-based immunological simulation

    PubMed Central

    Mitha, Faheem; Lucas, Timothy A; Feng, Feng; Kepler, Thomas B; Chan, Cliburn

    2008-01-01

    Background Computer simulations are of increasing importance in modeling biological phenomena. Their purpose is to predict behavior and guide future experiments. The aim of this project is to model the early immune response to vaccination by an agent based immune response simulation that incorporates realistic biophysics and intracellular dynamics, and which is sufficiently flexible to accurately model the multi-scale nature and complexity of the immune system, while maintaining the high performance critical to scientific computing. Results The Multiscale Systems Immunology (MSI) simulation framework is an object-oriented, modular simulation framework written in C++ and Python. The software implements a modular design that allows for flexible configuration of components and initialization of parameters, thus allowing simulations to be run that model processes occurring over different temporal and spatial scales. Conclusion MSI addresses the need for a flexible and high-performing agent based model of the immune system. PMID:18442405

  5. Thermodynamic modeling of the sorption of radioelements onto cementitious materials

    SciTech Connect

    Heath, T.G.; Ilett, D.J.; Tweed, C.J.

    1996-08-01

    A model has been developed for the sorption of radioelements onto cementitious materials based on the diffuse-layer modeling approach. The model assumes that silicon sites (>SiOH) and calcium sites (>CaOH) dominate the surface chemistry and the sorption of radioelements onto the cementitious materials. Both types of site may undergo surface protonation and deprotonation reactions. Cement-based systems vary greatly in their chemistry depending on their calcium-to-silicon molar ratio, and the corresponding variation in the surface chemistry has been incorporated by allowing sorption of calcium ions onto silicon sites. This process results in a change from a silica-type surface, at very low calcium-silicon ratios, to a calcium hydroxide-type surface for high-calcium cement-based materials. The predicted variation in the surface chemistry is consistent with literature data on measured zeta potentials of cements. The model has been applied successfully to describe the sorption of simple caesium and iodide ions at varying calcium-silicon ratios. In a Nirex repository for low and intermediate level wastes, a high-calcium cementitious backfill would be specified. This model has allowed a consistent interpretation of experimental data for sorption of key radioelements, including uranium and plutonium, onto the backfill, under saline and non-saline conditions.

  6. Multiscale Modeling, Simulation and Visualization and Their Potential for Future Aerospace Systems

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K. (Compiler)

    2002-01-01

    This document contains the proceedings of the Training Workshop on Multiscale Modeling, Simulation and Visualization and Their Potential for Future Aerospace Systems held at NASA Langley Research Center, Hampton, Virginia, March 5 - 6, 2002. The workshop was jointly sponsored by Old Dominion University's Center for Advanced Engineering Environments and NASA. Workshop attendees were from NASA, other government agencies, industry, and universities. The objectives of the workshop were to give overviews of the diverse activities in hierarchical approach to material modeling from continuum to atomistics; applications of multiscale modeling to advanced and improved material synthesis; defects, dislocations, and material deformation; fracture and friction; thin-film growth; characterization at nano and micro scales; and, verification and validation of numerical simulations, and to identify their potential for future aerospace systems.

  7. Multiscale dynamic analysis of blast furnace system based on intensive signal processing.

    PubMed

    Chu, Yanxu; Gao, Chuanhou; Liu, Xiangguan

    2010-09-01

    In this paper, the Hilbert-Huang transform method and time delay embedding method are applied to multiscale dynamic analysis on the time series of silicon content in hot metal collected from a medium-sized blast furnace with the inner volume of 2500 m3. The results provide clear evidence of multiscale features in blast furnace ironmaking process. Ten intrinsic mode functions (IMFs) are decomposed from the silicon content time series; the presence of noninteger fractal dimension, positive finite Kolmogorov entropy, and positive finite maximum Lyapunov exponent are found in some IMF components. In addition, the coupling of subscale structures of blast furnace system is studied using the dimension of interaction dynamics and a robust algorithm for detecting interdependence. It is found that IMF(3) is the main driver in the coupling system IMF(2) and IMF(3) while for the coupling system IMF(3) and IMF(4) neither subsystem can act as the driver. All these provide a guideline for studying blast furnace ironmaking process with multiscale theory and methods, and may open way for more candidate tools to model and control blast furnace system in the future.

  8. Experimental studies of bone mechanoadaptation: bridging in vitro and in vivo studies with multiscale systems

    PubMed Central

    Brown, Genevieve N.; Sattler, Rachel L.; Guo, X. Edward

    2016-01-01

    Despite advancements in technology and science over the last century, the mechanisms underlying Wolff's law—bone structure adaptation in response to physical stimuli—remain poorly understood, limiting the ability to effectively treat and prevent skeletal diseases. A challenge to overcome in the study of the underlying mechanisms of this principle is the multiscale nature of mechanoadaptation. While there exist in silico systems that are capable of studying across these scales, experimental studies are typically limited to interpretation at a single dimension or time point. For instance, studies of single-cell responses to defined physical stimuli offer only a limited prediction of the whole bone response, while overlapping pathways or compensatory mechanisms complicate the ability to isolate critical targets in a whole animal model. Thus, there exists a need to develop experimental systems capable of bridging traditional experimental approaches and informing existing multiscale theoretical models. The purpose of this article is to review the process of mechanoadaptation and inherent challenges in studying its underlying mechanisms, discuss the limitations of traditional experimental systems in capturing the many facets of this process and highlight three multiscale experimental systems which bridge traditional approaches and cover relatively understudied time and length scales in bone adaptation. PMID:26855756

  9. Glass cullet as a new supplementary cementitious material (SCM)

    NASA Astrophysics Data System (ADS)

    Mirzahosseini, Mohammadreza

    Finely ground glass has the potential for pozzolanic reactivity and can serve as a supplementary cementitious material (SCM). Glass reaction kinetics depends on both temperature and glass composition. Uniform composition, amorphous nature, and high silica content of glass make ground glass an ideal material for studying the effects of glass type and particle size on reactivity at different temperature. This study focuses on how three narrow size ranges of clear and green glass cullet, 63--75 mum, 25--38 mum, and smaller than 25 mum, as well as combination of glass types and particle sizes affects the microstructure and performance properties of cementitious systems containing glass cullet as a SCM. Isothermal calorimetry, chemical shrinkage, thermogravimetric analysis (TGA), quantitative analysis of X-ray diffraction (XRD), and analysis of scanning electron microscope (SEM) images in backscattered (BS) mode were used to quantify the cement reaction kinetics and microstructure. Additionally, compressive strength and water sorptivity experiments were performed on mortar samples to correlate reactivity of cementitious materials containing glass to the performance of cementitious mixtures. A recently-developed modeling platform called "muic the model" was used to simulated pozzolanic reactivity of single type and fraction size and combined types and particle sizes of finely ground glass. Results showed that ground glass exhibits pozzolanic properties, especially when particles of clear and green glass below 25 mum and their combination were used at elevated temperatures, reflecting that glass cullet is a temperature-sensitive SCM. Moreover, glass composition was seen to have a large impact on reactivity. In this study, green glass showed higher reactivity than clear glass. Results also revealed that the simultaneous effect of sizes and types of glass cullet (surface area) on the degree of hydration of glass particles can be accounted for through a linear addition

  10. Asymptotic behavior of gradient-like dynamical systems involving inertia and multiscale aspects

    NASA Astrophysics Data System (ADS)

    Attouch, Hedy; Czarnecki, Marc-Olivier

    2017-02-01

    In a Hilbert space H, we study the asymptotic behavior, as time variable t goes to +∞, of nonautonomous gradient-like dynamical systems involving inertia and multiscale features. Given Φ : H → R and Ψ : H → R two convex differentiable functions, γ a positive damping parameter, and ɛ (t) a function of t which tends to zero as t goes to +∞, we consider the second-order differential equation

  11. Using Multi-Scale Modeling Systems and Satellite Data to Study the Precipitation Processes

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Chern, J.; Lamg, S.; Matsui, T.; Shen, B.; Zeng, X.; Shi, R.

    2011-01-01

    In recent years, exponentially increasing computer power has extended Cloud Resolving Model (CRM) integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 km2 in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale model can be run in grid size similar to cloud resolving model through nesting technique. Recently, a multi-scale modeling system with unified physics was developed at NASA Goddard. It consists of (l) a cloud-resolving model (Goddard Cumulus Ensemble model, GCE model), (2) a regional scale model (a NASA unified weather research and forecast, WRF), (3) a coupled CRM and global model (Goddard Multi-scale Modeling Framework, MMF), and (4) a land modeling system. The same microphysical processes, long and short wave radiative transfer and land processes and the explicit cloud-radiation, and cloud-land surface interactive processes are applied in this multi-scale modeling system. This modeling system has been coupled with a multi-satellite simulator to use NASA high-resolution satellite data to identify the strengths and weaknesses of cloud and precipitation processes simulated by the model. In this talk, the recent developments and applications of the multi-scale modeling system will be presented. In particular, the results from using multi-scale modeling system to study the precipitating systems and hurricanes/typhoons will be presented. The high-resolution spatial and temporal visualization will be utilized to show the evolution of precipitation processes. Also how to

  12. Asynchronous coupling of hybrid models for efficient simulation of multiscale systems

    NASA Astrophysics Data System (ADS)

    Lockerby, Duncan A.; Patronis, Alexander; Borg, Matthew K.; Reese, Jason M.

    2015-03-01

    We present a new coupling approach for the time advancement of multi-physics models of multiscale systems. This extends the method of E et al. (2009) [5] to deal with an arbitrary number of models. Coupling is performed asynchronously, with each model being assigned its own timestep size. This enables accurate long timescale predictions to be made at the computational cost of the short timescale simulation. We propose a method for selecting appropriate timestep sizes based on the degree of scale separation that exists between models. A number of example applications are used for testing and benchmarking, including a comparison with experimental data of a thermally driven rarefied gas flow in a micro capillary. The multiscale simulation results are in very close agreement with the experimental data, but are produced almost 50,000 times faster than from a conventionally-coupled simulation.

  13. Simulation of Left Atrial Function Using a Multi-Scale Model of the Cardiovascular System

    PubMed Central

    Pironet, Antoine; Dauby, Pierre C.; Paeme, Sabine; Kosta, Sarah; Chase, J. Geoffrey; Desaive, Thomas

    2013-01-01

    During a full cardiac cycle, the left atrium successively behaves as a reservoir, a conduit and a pump. This complex behavior makes it unrealistic to apply the time-varying elastance theory to characterize the left atrium, first, because this theory has known limitations, and second, because it is still uncertain whether the load independence hypothesis holds. In this study, we aim to bypass this uncertainty by relying on another kind of mathematical model of the cardiac chambers. In the present work, we describe both the left atrium and the left ventricle with a multi-scale model. The multi-scale property of this model comes from the fact that pressure inside a cardiac chamber is derived from a model of the sarcomere behavior. Macroscopic model parameters are identified from reference dog hemodynamic data. The multi-scale model of the cardiovascular system including the left atrium is then simulated to show that the physiological roles of the left atrium are correctly reproduced. This include a biphasic pressure wave and an eight-shaped pressure-volume loop. We also test the validity of our model in non basal conditions by reproducing a preload reduction experiment by inferior vena cava occlusion with the model. We compute the variation of eight indices before and after this experiment and obtain the same variation as experimentally observed for seven out of the eight indices. In summary, the multi-scale mathematical model presented in this work is able to correctly account for the three roles of the left atrium and also exhibits a realistic left atrial pressure-volume loop. Furthermore, the model has been previously presented and validated for the left ventricle. This makes it a proper alternative to the time-varying elastance theory if the focus is set on precisely representing the left atrial and left ventricular behaviors. PMID:23755183

  14. Sustainable design and manufacturing of multifunctional polymer nanocomposite coatings: A multiscale systems approach

    NASA Astrophysics Data System (ADS)

    Xiao, Jie

    Polymer nanocomposites have a great potential to be a dominant coating material in a wide range of applications in the automotive, aerospace, ship-making, construction, and pharmaceutical industries. However, how to realize design sustainability of this type of nanostructured materials and how to ensure the true optimality of the product quality and process performance in coating manufacturing remain as a mountaintop area. The major challenges arise from the intrinsic multiscale nature of the material-process-product system and the need to manipulate the high levels of complexity and uncertainty in design and manufacturing processes. This research centers on the development of a comprehensive multiscale computational methodology and a computer-aided tool set that can facilitate multifunctional nanocoating design and application from novel function envisioning and idea refinement, to knowledge discovery and design solution derivation, and further to performance testing in industrial applications and life cycle analysis. The principal idea is to achieve exceptional system performance through concurrent characterization and optimization of materials, product and associated manufacturing processes covering a wide range of length and time scales. Multiscale modeling and simulation techniques ranging from microscopic molecular modeling to classical continuum modeling are seamlessly coupled. The tight integration of different methods and theories at individual scales allows the prediction of macroscopic coating performance from the fundamental molecular behavior. Goal-oriented design is also pursued by integrating additional methods for bio-inspired dynamic optimization and computational task management that can be implemented in a hierarchical computing architecture. Furthermore, multiscale systems methodologies are developed to achieve the best possible material application towards sustainable manufacturing. Automotive coating manufacturing, that involves paint spay and

  15. Multiscale enhanced sampling for protein systems: An extension via adiabatic separation

    NASA Astrophysics Data System (ADS)

    Moritsugu, Kei; Terada, Tohru; Kidera, Akinori

    2016-09-01

    Multiscale enhanced sampling (MSES) calculates the configurational ensemble of all-atom (MM) protein systems with the help of coupling to a coarse-grained (CG) model. Here, for further improvement of the sampling efficiency, the approximation of adiabatic separation was introduced to the original MSES, by adopting a high CG temperature limit. An application to the folding of chignolin in explicit solvent demonstrated that the MSES formula based on adiabatic separation correctly sampled the canonical ensemble with excellent efficiency and robustness against the parameter selection, and thus MSES successfully achieved the scalability for applications to large protein systems.

  16. Self-damping cementitious composites with multi-layer graphene

    NASA Astrophysics Data System (ADS)

    Ruan, Yanfeng; Zhou, Daocheng; Sun, Shengwei; Wu, Xinyi; Yu, Xun; Hou, Jilin; Dong, Xufeng; Han, Baoguo

    2017-07-01

    Cementitious composites are quasi-brittle and susceptible to damage under dynamic loads. The addition of nanoscale fillers into cementitious composites is an effective approach to address this issue. In this paper, multi-layer graphenes (MLGs) are incorporated into cementitious composites to enhance its damping property. The underlying modification mechanism of MLGs to cementitous composites is also investigated. Experimental results showed that the addition of MLGs can effectively modify the damping property of cementitious composites. Compared with cementitious composites without MLGs, the damping ratio of cementitious composites filled with 1% and 5% of MLGs increases by 16.22% and 45.73%, respectively. The improvement of MLGs to damping property of cementitious composites can be attributed to the interlayer slip of MLGs, viscous friction between MLGs and matrix, and excellent thermal conductivity of MLGs. Moreover, the damping ratio measured by time-domain exponential decay method and frequency-domain half-power bandwidth method is consistent.

  17. Influence of electrified surface of cementitious materials on structure formation of hardened cement paste

    NASA Astrophysics Data System (ADS)

    Alekseev, A.; Gusakov, A.

    2015-01-01

    To provide high strength and durability of concrete it is necessary to study the influence of physical and chemical and mechanical principles of dispersed cementitious systems. The experimental bench was developed to study the influence of electrified surface of cementitious materials on structure formation of hardened cement paste. The test bench allows accelerating the processes of dissolution of cementing materials in water due to influence of electric discharge on their surface. Cement activation with high-voltage corona discharge when AC current is applied allows increasing the ultimate compressive strength of hardened cement paste by 46% at the age of one day and by 20% at the age of 28 days.

  18. Design of microcamera for field curvature and distortion correction in monocentric multiscale foveated imaging system

    NASA Astrophysics Data System (ADS)

    Wu, Xiongxiong; Wang, Xiaorui; Zhang, Jianlei; Yuan, Ying; Chen, Xiaoxiang

    2017-04-01

    To realize large field of view (FOV) and high-resolution dynamic gaze of the moving target, this paper proposes the monocentric multiscale foveated (MMF) imaging system based on monocentric multiscale design and foveated imaging. First we present the MMF imaging system concept. Then we analyze large field curvature and distortion of the secondary image when the spherical intermediate image produced by the primary monocentric objective lens is relayed by the microcameras. Further a type of zoom endoscope objective lens is selected as the initial structure and optimized to minimize the field curvature and distortion with ZEMAX optical design software. The simulation results show that the maximum field curvature in full field of view is below 0.25 mm and the maximum distortion in full field of view is below 0.6%, which can meet the requirements of the microcamera in the proposed MMF imaging system. In addition, a simple doublet is used to design the foveated imaging system. Results of the microcamera together with the foveated imager compose the results of the whole MMF imaging system.

  19. Components for Atomistic-to-Continuum Multiscale Modeling of Flow in Micro- and Nanofluidic Systems

    DOE PAGES

    Adalsteinsson, Helgi; Debusschere, Bert J.; Long, Kevin R.; ...

    2008-01-01

    Micro- and nanofluidics pose a series of significant challenges for science-based modeling. Key among those are the wide separation of length- and timescales between interface phenomena and bulk flow and the spatially heterogeneous solution properties near solid-liquid interfaces. It is not uncommon for characteristic scales in these systems to span nine orders of magnitude from the atomic motions in particle dynamics up to evolution of mass transport at the macroscale level, making explicit particle models intractable for all but the simplest systems. Recently, atomistic-to-continuum (A2C) multiscale simulations have gained a lot of interest as an approach to rigorously handle particle-levelmore » dynamics while also tracking evolution of large-scale macroscale behavior. While these methods are clearly not applicable to all classes of simulations, they are finding traction in systems in which tight-binding, and physically important, dynamics at system interfaces have complex effects on the slower-evolving large-scale evolution of the surrounding medium. These conditions allow decomposition of the simulation into discrete domains, either spatially or temporally. In this paper, we describe how features of domain decomposed simulation systems can be harnessed to yield flexible and efficient software for multiscale simulations of electric field-driven micro- and nanofluidics.« less

  20. Diagnosing Disaster Resilience of Communities as Multi-scale Complex Socio-ecological Systems

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Mochizuki, Junko; Keating, Adriana; Mechler, Reinhard; Williges, Keith; Hochrainer, Stefan

    2014-05-01

    Global environmental change, growing anthropogenic influence, and increasing globalisation of society have made it clear that disaster vulnerability and resilience of communities cannot be understood without knowledge on the broader social-ecological system in which they are embedded. We propose a framework for diagnosing community resilience to disasters, as a form of disturbance to social-ecological systems, with feedbacks from the local to the global scale. Inspired by iterative multi-scale analysis employed by Resilience Alliance, the related socio-ecological systems framework of Ostrom, and the sustainable livelihood framework, we developed a multi-tier framework for thinking of communities as multi-scale social-ecological systems and analyzing communities' disaster resilience and also general resilience. We highlight the cross-scale influences and feedbacks on communities that exist from lower (e.g., household) to higher (e.g., regional, national) scales. The conceptual framework is then applied to a real-world resilience assessment situation, to illustrate how key components of socio-ecological systems, including natural hazards, natural and man-made environment, and community capacities can be delineated and analyzed.

  1. ELECANS--an integrated model development environment for multiscale cancer systems biology.

    PubMed

    Chaudhary, Safee Ullah; Shin, Sung-Young; Lee, Daewon; Song, Je-Hoon; Cho, Kwang-Hyun

    2013-04-01

    Computational multiscale models help cancer biologists to study the spatiotemporal dynamics of complex biological systems and to reveal the underlying mechanism of emergent properties. To facilitate the construction of such models, we have developed a next generation modelling platform for cancer systems biology, termed 'ELECANS' (electronic cancer system). It is equipped with a graphical user interface-based development environment for multiscale modelling along with a software development kit such that hierarchically complex biological systems can be conveniently modelled and simulated by using the graphical user interface/software development kit combination. Associated software accessories can also help users to perform post-processing of the simulation data for visualization and further analysis. In summary, ELECANS is a new modelling platform for cancer systems biology and provides a convenient and flexible modelling and simulation environment that is particularly useful for those without an intensive programming background. ELECANS, its associated software accessories, demo examples, documentation and issues database are freely available at http://sbie.kaist.ac.kr/sub_0204.php. Supplementary data are available at Bioinformatics online.

  2. A unified double-loop multi-scale control strategy for NMP integrating-unstable systems

    NASA Astrophysics Data System (ADS)

    Seer, Qiu Han; Nandong, Jobrun

    2016-03-01

    This paper presents a new control strategy which unifies the direct and indirect multi-scale control schemes via a double-loop control structure. This unified control strategy is proposed for controlling a class of highly nonminimum-phase processes having both integrating and unstable modes. This type of systems is often encountered in fed-batch fermentation processes which are very difficult to stabilize via most of the existing well-established control strategies. A systematic design procedure is provided where its applicability is demonstrated via a numerical example.

  3. Simulating microbial systems: addressing model uncertainty/incompleteness via multiscale and entropy methods.

    PubMed

    Singharoy, A; Joshi, H; Cheluvaraja, S; Miao, Y; Brown, D; Ortoleva, P

    2012-01-01

    Most systems of interest in the natural and engineering sciences are multiscale in character. Typically available models are incomplete or uncertain. Thus, a probabilistic approach is required. We present a deductive multiscale approach to address such problems, focusing on virus and cell systems to demonstrate the ideas. There is usually an underlying physical model, all factors in which (e.g., particle masses, charges, and force constants) are known. For example, the underlying model can be cast in terms of a collection of N-atoms evolving via Newton's equations. When the number of atoms is 10(6) or more, these physical models cannot be simulated directly. However, one may only be interested in a coarse-grained description, e.g., in terms of molecular populations or overall system size, shape, position, and orientation. The premise of this chapter is that the coarse-grained equations should be derived from the underlying model so that a deductive calibration-free methodology is achieved. We consider a reduction in resolution from a description for the state of N-atoms to one in terms of coarse-grained variables. This implies a degree of uncertainty in the underlying microstates. We present a methodology for modeling microbial systems that integrates equations for coarse-grained variables with a probabilistic description of the underlying fine-scale ones. The implementation of our strategy as a general computational platform (SimEntropics™) for microbial modeling and prospects for developments and applications are discussed.

  4. Multirate method for co-simulation of electrical-chemical systems in multiscale modeling.

    PubMed

    Brocke, Ekaterina; Djurfeldt, Mikael; Bhalla, Upinder S; Kotaleski, Jeanette Hellgren; Hanke, Michael

    2017-04-07

    Multiscale modeling by means of co-simulation is a powerful tool to address many vital questions in neuroscience. It can for example be applied in the study of the process of learning and memory formation in the brain. At the same time the co-simulation technique makes it possible to take advantage of interoperability between existing tools and multi-physics models as well as distributed computing. However, the theoretical basis for multiscale modeling is not sufficiently understood. There is, for example, a need of efficient and accurate numerical methods for time integration. When time constants of model components are different by several orders of magnitude, individual dynamics and mathematical definitions of each component all together impose stability, accuracy and efficiency challenges for the time integrator. Following our numerical investigations in Brocke et al. (Frontiers in Computational Neuroscience, 10, 97, 2016), we present a new multirate algorithm that allows us to handle each component of a large system with a step size appropriate to its time scale. We take care of error estimates in a recursive manner allowing individual components to follow their discretization time course while keeping numerical error within acceptable bounds. The method is developed with an ultimate goal of minimizing the communication between the components. Thus it is especially suitable for co-simulations. Our preliminary results support our confidence that the multirate approach can be used in the class of problems we are interested in. We show that the dynamics ofa communication signal as well as an appropriate choice of the discretization order between system components may have a significant impact on the accuracy of the coupled simulation. Although, the ideas presented in the paper have only been tested on a single model, it is likely that they can be applied to other problems without loss of generality. We believe that this work may significantly contribute to the

  5. A multi-scale strategy for discovery of novel endogenous neuropeptides in the crustacean nervous system.

    PubMed

    Jia, Chenxi; Lietz, Christopher B; Ye, Hui; Hui, Limei; Yu, Qing; Yoo, Sujin; Li, Lingjun

    2013-10-08

    The conventional mass spectrometry (MS)-based strategy is often inadequate for the comprehensive characterization of various size neuropeptides without the assistance of genomic information. This study evaluated sequence coverage of different size neuropeptides in two crustacean species, blue crab Callinectes sapidus and Jonah crab Cancer borealis using conventional MS methodologies and revealed limitations to mid- and large-size peptide analysis. Herein we attempt to establish a multi-scale strategy for simultaneous and confident sequence elucidation of various sizes of peptides in the crustacean nervous system. Nine novel neuropeptides spanning a wide range of molecular weights (0.9-8.2kDa) were fully sequenced from a major neuroendocrine organ, the sinus gland of the spiny lobster Panulirus interruptus. These novel neuropeptides included seven allatostatin (A- and B-type) peptides, one crustacean hyperglycemic hormone precursor-related peptide, and one crustacean hyperglycemic hormone. Highly accurate multi-scale characterization of a collection of varied size neuropeptides was achieved by integrating traditional data-dependent tandem MS, improved bottom-up sequencing, multiple fragmentation technique-enabled top-down sequencing, chemical derivatization, and in silico homology search. Collectively, the ability to characterize a neuropeptidome with vastly differing molecule sizes from a neural tissue extract could find great utility in unraveling complex signaling peptide mixtures employed by other biological systems. Mass spectrometry (MS)-based neuropeptidomics aims to completely characterize the neuropeptides in a target organism as an important first step toward a better understanding of the structure and function of these complex signaling molecules. Although liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) with data-dependent acquisition is a powerful tool in peptidomic research, it often lacks the capability for de novo sequencing of

  6. Multi-Scale Molecular Deconstruction of the Serotonin Neuron System.

    PubMed

    Okaty, Benjamin W; Freret, Morgan E; Rood, Benjamin D; Brust, Rachael D; Hennessy, Morgan L; deBairos, Danielle; Kim, Jun Chul; Cook, Melloni N; Dymecki, Susan M

    2015-11-18

    Serotonergic (5HT) neurons modulate diverse behaviors and physiology and are implicated in distinct clinical disorders. Corresponding diversity in 5HT neuronal phenotypes is becoming apparent and is likely rooted in molecular differences, yet a comprehensive approach characterizing molecular variation across the 5HT system is lacking, as is concomitant linkage to cellular phenotypes. Here we combine intersectional fate mapping, neuron sorting, and genome-wide RNA-seq to deconstruct the mouse 5HT system at multiple levels of granularity-from anatomy, to genetic sublineages, to single neurons. Our unbiased analyses reveal principles underlying system organization, 5HT neuron subtypes, constellations of differentially expressed genes distinguishing subtypes, and predictions of subtype-specific functions. Using electrophysiology, subtype-specific neuron silencing, and conditional gene knockout, we show that these molecularly defined 5HT neuron subtypes are functionally distinct. Collectively, this resource classifies molecular diversity across the 5HT system and discovers sertonergic subtypes, markers, organizing principles, and subtype-specific functions with potential disease relevance.

  7. A Multiscale Modeling System: Developments, Applications, and Critical Issues

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Lau, William; Simpson, Joanne; Chern, Jiun-Dar; Atlas, Robert; Khairoutdinov, David Randall Marat; Li, Jui-Lin; Waliser, Duane E.; Jiang, Jonathan; Hou, Arthur; Lin, Xin; Peters-Lidard, Christa

    2009-01-01

    The foremost challenge in parameterizing convective clouds and cloud systems in large-scale models are the many coupled dynamical and physical processes that interact over a wide range of scales, from microphysical scales to the synoptic and planetary scales. This makes the comprehension and representation of convective clouds and cloud systems one of the most complex scientific problems in Earth science. During the past decade, the Global Energy and Water Cycle Experiment (GEWEX) Cloud System Study (GCSS) has pioneered the use of single-column models (SCMs) and cloud-resolving models (CRMs) for the evaluation of the cloud and radiation parameterizations in general circulation models (GCMs; e.g., GEWEX Cloud System Science Team 1993). These activities have uncovered many systematic biases in the radiation, cloud and convection parameterizations of GCMs and have led to the development of new schemes (e.g., Zhang 2002; Pincus et al, 2003; Zhang and Wu 2003; Wu et al. 2003; Liang and Wu 2005; Wu and Liang 2005, and others). Comparisons between SCMs and CRMs using the same large-scale forcing derived from field campaigns have demonstrated that CRMs are superior to SCMs in the prediction of temperature and moisture tendencies (e.g., Das et al. 1999; Randall et al 2003b; Xie et al. 2005).

  8. Toward a multi-scale simulation of lipid bilayer systems

    NASA Astrophysics Data System (ADS)

    Sugii, Taisuke; Takagi, Shu; Matsumoto, Yoichiro

    2006-03-01

    In numerical simulations of lipid bilayer systems, it has become important to treat the membrane molecules (e.g., lipids, proteins, and drug molecules) explicitly for designing medical drugs and for developing drug delivery systems. However, it is difficult to apply straightforwardly a microscopic simulation technique such as the molecular dynamics method to the large-scale bilayer systems, because the length and the time scales of these systems are very large compared to the scales of the molecules. The authors take two approaches for this problem. First, we use the dissipative particle dynamics method and the coarse grained molecular dynamics method in addition to the standard molecular dynamics method. The results are compared with the molecular-dynamics results and experimental data. Secondly we use a molecular dynamics and continuum hybrid simulation method. In this method, the region near the membrane is computed by an atomistic-simulation method and the solvent region is computed by a continuum-simulation method. (In our study, the coarse grained molecular dynamics was used for the atomistic region.) The validity and availability of this later approach will be discussed.

  9. Multi-Scale Molecular Deconstruction of the Serotonin Neuron System

    PubMed Central

    Okaty, Benjamin W.; Freret, Morgan E.; Rood, Benjamin D.; Brust, Rachael D.; Hennessy, Morgan L.; deBairos, Danielle; Kim, Jun Chul; Cook, Melloni N.; Dymecki, Susan M.

    2016-01-01

    Summary Serotonergic (5HT) neurons modulate diverse behaviors and physiology and are implicated in distinct clinical disorders. Corresponding diversity in 5HT neuronal phenotypes is becoming apparent and is likely rooted in molecular differences, yet a comprehensive approach characterizing molecular variation across the 5HT system is lacking, as is concomitant linkage to cellular phenotypes. Here we combine intersectional fate mapping, neuron sorting, and genome-wide RNA-Seq to deconstruct the mouse 5HT system at multiple levels of granularity—from anatomy, to genetic sublineages, to single neurons. Our unbiased analyses reveal: principles underlying system organization, novel 5HT neuron subtypes, constellations of differentially expressed genes distinguishing subtypes, and predictions of subtype-specific functions. Using electrophysiology, subtype-specific neuron silencing, and conditional gene knockout, we show that these molecularly defined 5HT neuron subtypes are functionally distinct. Collectively, this resource classifies molecular diversity across the 5HT system and discovers new subtypes, markers, organizing principles, and subtype-specific functions with potential disease relevance. PMID:26549332

  10. Strontium Uptake by Cementitious Materials

    SciTech Connect

    Wieland,E.; Tits, J.; Kunz, D.; Dahn, R.

    2008-01-01

    Wet chemistry experiments and X-ray absorption fine structure (XAFS) measurements were carried out to investigate the immobilization of nonradioactive Sr and 85Sr in calcite-free and calcite-containing Portland cement. The partitioning of pristine Sr between hardened cement paste (HCP) and pore solution, and the uptake of 85Sr and nonradioactive Sr were investigated in batch-type sorption/desorption experiments. Sr uptake by HCP was found to be fast and nearly linear for both cements, indicating that differences in the compositions of the two cements have no influence on Sr binding. The partitioning of pristine Sr bound in the cement matrix and 85Sr between HCP and pore solution could be modeled in terms of a reversible sorption process using similar Kd values. These findings allow 85Sr uptake to be interpreted in terms of an isotopic exchange process with pristine Sr. Sr K-edge EXAFS measurements on Sr doped HCP and calcium silicate hydrate (C-S-H) samples reveal no significant differences in the local coordination environments of pristine Sr and Sr bound to the cement matrix upon sorption. The first coordination sphere consists of five to six oxygen atoms located at a distance of about 2.6 Angstroms, which corresponds to Sr-O distances in the hydration sphere of Sr2+ in alkaline solution. Sr binds to the cement matrix via two bridging oxygen atoms located at a distance of about 3.6 Angstroms. No further neighboring atoms could be detected, indicating that Sr is taken up as a partially hydrated species by HCP. Wet chemistry and spectroscopic data further indicate that Sr binding to C-S-H phases is likely to be the controlling uptake mechanism in the cement matrix, which allows Sr uptake by HCP to be predicted based on a Ca-Sr ion exchange model previously developed for Sr binding to C-S-H phases. The latter finding suggests that long-term predictions of Sr immobilization in the cementitious near field of repositories for radioactive waste can be based on a

  11. Multiscale Analysis of Nonlinear Systems Using Computational Topology

    SciTech Connect

    Schatz, Michael F.; Mischaikow, Konstantin; Kalies, William; Wanner, Thomas

    2010-08-31

    Computational Homology in Fluids: M. Schatz, K. Mischaikow. This effort focused on characterizing both the structure and dynamics of complex spatio-temporal flows that arise in thermal convection. Microstructure Characterization: T. Wanner, K. Mischaikow. We extended our previous work on studying the time evolution of patterns associated with phase separation in conserved concentration fields. Probabilistic Homology Validation: W. Kalies, T. Wanner, K. Mischaikow. Our above mentioned work on microstructure characterization is based on numerically studying the homology of certain sublevel sets of a function, whose evolution is described by deterministic or stochastic evolution equations. Computational Homology and Dynamics: W. Kalies, T. Wanner, K. Mischaikow. Topological methods can be used to rigorously describe the dynamics of nonlinear systems. We are approaching this problem from several perspectives and through a variety of systems. Stress Networks in Polycrystals: T. Wanner. Together with E. Fuller (NIST) and D. Saylor (FDA) we have characterized stress networks in polycrystals. This part of the project is aimed at developing homological metrics which can aid in distinguishing not only microstructures, but also derived mechanical response fields. Microstructure-Controlled Drug Release: K. Mischaikow, T. Wanner. This part of the project is concerned with the development of topological metrics in the context of controlled drug delivery systems, such as drug-eluting stents. We are particularly interested in developing metrics which can be used to link the processing stage to the resulting microstructure, and ultimately to the achieved system response in terms of drug release profiles. Microstructure of Fuel Cells: W. Kalies, K. Mischaikow. In collaboration with P. Voorhees (Northwestern Univ.) and M. Gameiro (Rutgers) we have been using our computational homology software to analyze the topological structure of the void, metal and ceramic components of a Solid

  12. Dynamical systems with multiple long-delayed feedbacks: Multiscale analysis and spatiotemporal equivalence

    NASA Astrophysics Data System (ADS)

    Yanchuk, Serhiy; Giacomelli, Giovanni

    2015-10-01

    Dynamical systems with multiple, hierarchically long-delayed feedback are introduced and studied extending our previous work [Yanchuk and Giacomelli, Phys. Rev. Lett. 112, 174103 (2014), 10.1103/PhysRevLett.112.174103]. Focusing on the phenomenological model of a Stuart-Landau oscillator with two feedbacks, we show the multiscale properties of its dynamics and demonstrate them by means of a space-time representation. For sufficiently long delays, we derive a normal form describing the system close to the destabilization. The space and temporal variables, which are involved in the space-time representation, correspond to suitable time scales of the original system. The physical meaning of the results, together with the interpretation of the description at different scales, is presented and discussed. In particular, it is shown how this representation uncovers hidden multiscale patterns such as spirals or spatiotemporal chaos. The effect of the delay size and the features of the transition between small and large delays is also analyzed. Finally, we comment on the application of the method and on its extension to an arbitrary, but finite, number of delayed feedback terms.

  13. Multiscale Support Vector Learning With Projection Operator Wavelet Kernel for Nonlinear Dynamical System Identification.

    PubMed

    Lu, Zhao; Sun, Jing; Butts, Kenneth

    2016-02-03

    A giant leap has been made in the past couple of decades with the introduction of kernel-based learning as a mainstay for designing effective nonlinear computational learning algorithms. In view of the geometric interpretation of conditional expectation and the ubiquity of multiscale characteristics in highly complex nonlinear dynamic systems [1]-[3], this paper presents a new orthogonal projection operator wavelet kernel, aiming at developing an efficient computational learning approach for nonlinear dynamical system identification. In the framework of multiresolution analysis, the proposed projection operator wavelet kernel can fulfill the multiscale, multidimensional learning to estimate complex dependencies. The special advantage of the projection operator wavelet kernel developed in this paper lies in the fact that it has a closed-form expression, which greatly facilitates its application in kernel learning. To the best of our knowledge, it is the first closed-form orthogonal projection wavelet kernel reported in the literature. It provides a link between grid-based wavelets and mesh-free kernel-based methods. Simulation studies for identifying the parallel models of two benchmark nonlinear dynamical systems confirm its superiority in model accuracy and sparsity.

  14. Integration of multiscale dendritic spine structure and function data into systems biology models.

    PubMed

    Mancuso, James J; Cheng, Jie; Yin, Zheng; Gilliam, Jared C; Xia, Xiaofeng; Li, Xuping; Wong, Stephen T C

    2014-01-01

    Comprising 10(11) neurons with 10(14) synaptic connections the human brain is the ultimate systems biology puzzle. An increasing body of evidence highlights the observation that changes in brain function, both normal and pathological, consistently correlate with dynamic changes in neuronal anatomy. Anatomical changes occur on a full range of scales from the trafficking of individual proteins, to alterations in synaptic morphology both individually and on a systems level, to reductions in long distance connectivity and brain volume. The major sites of contact for synapsing neurons are dendritic spines, which provide an excellent metric for the number and strength of signaling connections between elements of functional neuronal circuits. A comprehensive model of anatomical changes and their functional consequences would be a holy grail for the field of systems neuroscience but its realization appears far on the horizon. Various imaging technologies have advanced to allow for multi-scale visualization of brain plasticity and pathology, but computational analysis of the big data sets involved forms the bottleneck toward the creation of multiscale models of brain structure and function. While a full accounting of techniques and progress toward a comprehensive model of brain anatomy and function is beyond the scope of this or any other single paper, this review serves to highlight the opportunities for analysis of neuronal spine anatomy and function provided by new imaging technologies and the high-throughput application of older technologies while surveying the strengths and weaknesses of currently available computational analytical tools and room for future improvement.

  15. A Multiscale Material Testing System for In Situ Optical and Electron Microscopes and Its Application

    PubMed Central

    Ye, Xuan; Cui, Zhiguo; Fang, Huajun; Li, Xide

    2017-01-01

    We report a novel material testing system (MTS) that uses hierarchical designs for in-situ mechanical characterization of multiscale materials. This MTS is adaptable for use in optical microscopes (OMs) and scanning electron microscopes (SEMs). The system consists of a microscale material testing module (m-MTM) and a nanoscale material testing module (n-MTM). The MTS can measure mechanical properties of materials with characteristic lengths ranging from millimeters to tens of nanometers, while load capacity can vary from several hundred micronewtons to several nanonewtons. The m-MTM is integrated using piezoelectric motors and piezoelectric stacks/tubes to form coarse and fine testing modules, with specimen length from millimeters to several micrometers, and displacement distances of 12 mm with 0.2 µm resolution for coarse level and 8 µm with 1 nm resolution for fine level. The n-MTM is fabricated using microelectromechanical system technology to form active and passive components and realizes material testing for specimen lengths ranging from several hundred micrometers to tens of nanometers. The system’s capabilities are demonstrated by in-situ OM and SEM testing of the system’s performance and mechanical properties measurements of carbon fibers and metallic microwires. In-situ multiscale deformation tests of Bacillus subtilis filaments are also presented. PMID:28777341

  16. Adapting to a changing environment: non-obvious thresholds in multi-scale systems.

    PubMed

    Perryman, Clare; Wieczorek, Sebastian

    2014-10-08

    Many natural and technological systems fail to adapt to changing external conditions and move to a different state if the conditions vary too fast. Such 'non-adiabatic' processes are ubiquitous, but little understood. We identify these processes with a new nonlinear phenomenon-an intricate threshold where a forced system fails to adiabatically follow a changing stable state. In systems with multiple time scales, we derive existence conditions that show such thresholds to be generic, but non-obvious, meaning they cannot be captured by traditional stability theory. Rather, the phenomenon can be analysed using concepts from modern singular perturbation theory: folded singularities and canard trajectories, including composite canards. Thus, non-obvious thresholds should explain the failure to adapt to a changing environment in a wide range of multi-scale systems including: tipping points in the climate system, regime shifts in ecosystems, excitability in nerve cells, adaptation failure in regulatory genes and adiabatic switching in technology.

  17. Circular causality in integrative multi-scale systems biology and its interaction with traditional medicine.

    PubMed

    Tasaki, Kazuyo Maria

    2013-04-01

    This paper discusses the concept of circular causality in "biological relativity" (Noble, Interface Focus. 2, 56-64, 2012) in the context of integrative and multi-scale systems approaches to biology. It also discusses the relationship between systems biology and traditional medicine (sometimes called scholarly medical traditions) mainly from East Asia and India. Systems biology helps illuminate circular processes identified in traditional medicine, while the systems concept of attractors in complex systems will also be important in analysing dynamic balance in the body processes that traditional medicine is concerned with. Ways of nudging disordered processes towards good attractors through the use of traditional medicines can lead to the development of new ways not only of curing disease but also of its prevention. Examples are given of cost-effective multi-component remedies that use integrative ideas derived from traditional medicine.

  18. Multiscale analysis of nonlinear systems using computational homology

    SciTech Connect

    Konstantin Mischaikow; Michael Schatz; William Kalies; Thomas Wanner

    2010-05-24

    - We extended our previous work on studying the time evolution of patterns associated with phase separation in conserved concentration fields. (6) Probabilistic Homology Validation - work on microstructure characterization is based on numerically studying the homology of certain sublevel sets of a function, whose evolution is described by deterministic or stochastic evolution equations. (7) Computational Homology and Dynamics - Topological methods can be used to rigorously describe the dynamics of nonlinear systems. We are approaching this problem from several perspectives and through a variety of systems. (8) Stress Networks in Polycrystals - we have characterized stress networks in polycrystals. This part of the project is aimed at developing homological metrics which can aid in distinguishing not only microstructures, but also derived mechanical response fields. (9) Microstructure-Controlled Drug Release - This part of the project is concerned with the development of topological metrics in the context of controlled drug delivery systems, such as drug-eluting stents. We are particularly interested in developing metrics which can be used to link the processing stage to the resulting microstructure, and ultimately to the achieved system response in terms of drug release profiles. (10) Microstructure of Fuel Cells - we have been using our computational homology software to analyze the topological structure of the void, metal and ceramic components of a Solid Oxide Fuel Cell.

  19. Multiscale mechanobiology: computational models for integrating molecules to multicellular systems

    PubMed Central

    Mak, Michael; Kim, Taeyoon

    2015-01-01

    Mechanical signals exist throughout the biological landscape. Across all scales, these signals, in the form of force, stiffness, and deformations, are generated and processed, resulting in an active mechanobiological circuit that controls many fundamental aspects of life, from protein unfolding and cytoskeletal remodeling to collective cell motions. The multiple scales and complex feedback involved present a challenge for fully understanding the nature of this circuit, particularly in development and disease in which it has been implicated. Computational models that accurately predict and are based on experimental data enable a means to integrate basic principles and explore fine details of mechanosensing and mechanotransduction in and across all levels of biological systems. Here we review recent advances in these models along with supporting and emerging experimental findings. PMID:26019013

  20. Multiscale analysis of nonlinear systems using computational homology

    SciTech Connect

    Konstantin Mischaikow, Rutgers University /Georgia Institute of Technology, Michael Schatz, Georgia Institute of Technology, William Kalies, Florida Atlantic University, Thomas Wanner,George Mason University

    2010-05-19

    - We extended our previous work on studying the time evolution of patterns associated with phase separation in conserved concentration fields. (6) Probabilistic Homology Validation - work on microstructure characterization is based on numerically studying the homology of certain sublevel sets of a function, whose evolution is described by deterministic or stochastic evolution equations. (7) Computational Homology and Dynamics - Topological methods can be used to rigorously describe the dynamics of nonlinear systems. We are approaching this problem from several perspectives and through a variety of systems. (8) Stress Networks in Polycrystals - we have characterized stress networks in polycrystals. This part of the project is aimed at developing homological metrics which can aid in distinguishing not only microstructures, but also derived mechanical response fields. (9) Microstructure-Controlled Drug Release - This part of the project is concerned with the development of topological metrics in the context of controlled drug delivery systems, such as drug-eluting stents. We are particularly interested in developing metrics which can be used to link the processing stage to the resulting microstructure, and ultimately to the achieved system response in terms of drug release profiles. (10) Microstructure of Fuel Cells - we have been using our computational homology software to analyze the topological structure of the void, metal and ceramic components of a Solid Oxide Fuel Cell.

  1. Conservative tightly-coupled simulations of stochastic multiscale systems

    NASA Astrophysics Data System (ADS)

    Taverniers, Søren; Pigarov, Alexander Y.; Tartakovsky, Daniel M.

    2016-05-01

    Multiphysics problems often involve components whose macroscopic dynamics is driven by microscopic random fluctuations. The fidelity of simulations of such systems depends on their ability to propagate these random fluctuations throughout a computational domain, including subdomains represented by deterministic solvers. When the constituent processes take place in nonoverlapping subdomains, system behavior can be modeled via a domain-decomposition approach that couples separate components at the interfaces between these subdomains. Its coupling algorithm has to maintain a stable and efficient numerical time integration even at high noise strength. We propose a conservative domain-decomposition algorithm in which tight coupling is achieved by employing either Picard's or Newton's iterative method. Coupled diffusion equations, one of which has a Gaussian white-noise source term, provide a computational testbed for analysis of these two coupling strategies. Fully-converged (;implicit;) coupling with Newton's method typically outperforms its Picard counterpart, especially at high noise levels. This is because the number of Newton iterations scales linearly with the amplitude of the Gaussian noise, while the number of Picard iterations can scale superlinearly. At large time intervals between two subsequent inter-solver communications, the solution error for single-iteration (;explicit;) Picard's coupling can be several orders of magnitude higher than that for implicit coupling. Increasing the explicit coupling's communication frequency reduces this difference, but the resulting increase in computational cost can make it less efficient than implicit coupling at similar levels of solution error, depending on the communication frequency of the latter and the noise strength. This trend carries over into higher dimensions, although at high noise strength explicit coupling may be the only computationally viable option.

  2. Conservative tightly-coupled simulations of stochastic multiscale systems

    SciTech Connect

    Taverniers, Søren; Pigarov, Alexander Y.; Tartakovsky, Daniel M.

    2016-05-15

    Multiphysics problems often involve components whose macroscopic dynamics is driven by microscopic random fluctuations. The fidelity of simulations of such systems depends on their ability to propagate these random fluctuations throughout a computational domain, including subdomains represented by deterministic solvers. When the constituent processes take place in nonoverlapping subdomains, system behavior can be modeled via a domain-decomposition approach that couples separate components at the interfaces between these subdomains. Its coupling algorithm has to maintain a stable and efficient numerical time integration even at high noise strength. We propose a conservative domain-decomposition algorithm in which tight coupling is achieved by employing either Picard's or Newton's iterative method. Coupled diffusion equations, one of which has a Gaussian white-noise source term, provide a computational testbed for analysis of these two coupling strategies. Fully-converged (“implicit”) coupling with Newton's method typically outperforms its Picard counterpart, especially at high noise levels. This is because the number of Newton iterations scales linearly with the amplitude of the Gaussian noise, while the number of Picard iterations can scale superlinearly. At large time intervals between two subsequent inter-solver communications, the solution error for single-iteration (“explicit”) Picard's coupling can be several orders of magnitude higher than that for implicit coupling. Increasing the explicit coupling's communication frequency reduces this difference, but the resulting increase in computational cost can make it less efficient than implicit coupling at similar levels of solution error, depending on the communication frequency of the latter and the noise strength. This trend carries over into higher dimensions, although at high noise strength explicit coupling may be the only computationally viable option.

  3. Technetium Sorption by Cementitious Materials Under Reducing Conditions

    SciTech Connect

    Kaplan, Daniel I.; Estes, Shanna L.; Powell, Brian A.

    2012-09-28

    The objective of this study was to measure technetium ({sup 99}Tc) sorption to cementitious materials under reducing conditions to simulate Saltstone Disposal Facility conditions. {sup 99}Tc(VII) batch sorption experiments were conducted for 319 days in an inert glovebag with a variety of cementitious materials (aged cement, Vault 2, TR545, and TR547) containing varying amounts of blast furnace slag. Between 154 and 319 days, the {sup 99}Tc aqueous concentrations tended to remain constant and samples amended with different initial {sup 99}Tc concentrations, tended to merge at about 10{sup -9} M for Vault 2 (17% slag) and TR545 (90% slag) and 10{sup -8} M for TR547 (45% slag). This data provided strong evidence that solubility, and not adsorption (K{sub d} values), was controlling aqueous {sup 99}Tc concentrations. Laboratory data superimposed over thermodynamic speciation diagrams further supported the conclusion that solubility, and not adsorption controlled {sup 99}Tc aqueous concentrations. The oxidation state of the aqueous {sup 99}Tc at the end of the sorption experiment was determined by solvent extraction to be almost entirely {sup 99}Tc(VII). The pH of the present system was ~11.8. Previously proposed solubility controlling phases including Tc-sulfides may be present, but do not appear to control solubility. After the 319 day sorption period, the suspensions were removed from the glovebag and a desorption step under oxic conditions was conducted for 20 days by adding oxic, pH-buffered solutions to the suspensions. {sup 99}Tc aqueous concentrations increased by more than an order of magnitude and Eh increased by several hundred millivolts within 24 hours after the introduction of the oxic solutions. These desorption results are consistent with re-oxidation and dissolution/desorption of {sup 99}Tc(IV) phases possibly present in the cementitious materials after the anoxic sorption step of the experiment. Aqueous {sup 99}Tc concentrations continued to increase

  4. Complexity and multifractal behaviors of multiscale-continuum percolation financial system for Chinese stock markets

    NASA Astrophysics Data System (ADS)

    Zeng, Yayun; Wang, Jun; Xu, Kaixuan

    2017-04-01

    A new financial agent-based time series model is developed and investigated by multiscale-continuum percolation system, which can be viewed as an extended version of continuum percolation system. In this financial model, for different parameters of proportion and density, two Poisson point processes (where the radii of points represent the ability of receiving or transmitting information among investors) are applied to model a random stock price process, in an attempt to investigate the fluctuation dynamics of the financial market. To validate its effectiveness and rationality, we compare the statistical behaviors and the multifractal behaviors of the simulated data derived from the proposed model with those of the real stock markets. Further, the multiscale sample entropy analysis is employed to study the complexity of the returns, and the cross-sample entropy analysis is applied to measure the degree of asynchrony of return autocorrelation time series. The empirical results indicate that the proposed financial model can simulate and reproduce some significant characteristics of the real stock markets to a certain extent.

  5. THERMALLY CONDUCTIVE CEMENTITIOUS GROUTS FOR GEOTHERMAL HEAT PUMPS. PROGRESS REPORT BY 1998

    SciTech Connect

    ALLAN,M.L.; PHILIPPACOPOULOS,A.J.

    1998-11-01

    Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98.

  6. Downscaling modelling system for multi-scale air quality forecasting

    NASA Astrophysics Data System (ADS)

    Nuterman, R.; Baklanov, A.; Mahura, A.; Amstrup, B.; Weismann, J.

    2010-09-01

    Urban modelling for real meteorological situations, in general, considers only a small part of the urban area in a micro-meteorological model, and urban heterogeneities outside a modelling domain affect micro-scale processes. Therefore, it is important to build a chain of models of different scales with nesting of higher resolution models into larger scale lower resolution models. Usually, the up-scaled city- or meso-scale models consider parameterisations of urban effects or statistical descriptions of the urban morphology, whereas the micro-scale (street canyon) models are obstacle-resolved and they consider a detailed geometry of the buildings and the urban canopy. The developed system consists of the meso-, urban- and street-scale models. First, it is the Numerical Weather Prediction (HIgh Resolution Limited Area Model) model combined with Atmospheric Chemistry Transport (the Comprehensive Air quality Model with extensions) model. Several levels of urban parameterisation are considered. They are chosen depending on selected scales and resolutions. For regional scale, the urban parameterisation is based on the roughness and flux corrections approach; for urban scale - building effects parameterisation. Modern methods of computational fluid dynamics allow solving environmental problems connected with atmospheric transport of pollutants within urban canopy in a presence of penetrable (vegetation) and impenetrable (buildings) obstacles. For local- and micro-scales nesting the Micro-scale Model for Urban Environment is applied. This is a comprehensive obstacle-resolved urban wind-flow and dispersion model based on the Reynolds averaged Navier-Stokes approach and several turbulent closures, i.e. k -ɛ linear eddy-viscosity model, k - ɛ non-linear eddy-viscosity model and Reynolds stress model. Boundary and initial conditions for the micro-scale model are used from the up-scaled models with corresponding interpolation conserving the mass. For the boundaries a

  7. Multi-scale Modeling of the Cardiovascular System: Disease Development, Progression, and Clinical Intervention.

    PubMed

    Zhang, Yanhang; Barocas, Victor H; Berceli, Scott A; Clancy, Colleen E; Eckmann, David M; Garbey, Marc; Kassab, Ghassan S; Lochner, Donna R; McCulloch, Andrew D; Tran-Son-Tay, Roger; Trayanova, Natalia A

    2016-09-01

    Cardiovascular diseases (CVDs) are the leading cause of death in the western world. With the current development of clinical diagnostics to more accurately measure the extent and specifics of CVDs, a laudable goal is a better understanding of the structure-function relation in the cardiovascular system. Much of this fundamental understanding comes from the development and study of models that integrate biology, medicine, imaging, and biomechanics. Information from these models provides guidance for developing diagnostics, and implementation of these diagnostics to the clinical setting, in turn, provides data for refining the models. In this review, we introduce multi-scale and multi-physical models for understanding disease development, progression, and designing clinical interventions. We begin with multi-scale models of cardiac electrophysiology and mechanics for diagnosis, clinical decision support, personalized and precision medicine in cardiology with examples in arrhythmia and heart failure. We then introduce computational models of vasculature mechanics and associated mechanical forces for understanding vascular disease progression, designing clinical interventions, and elucidating mechanisms that underlie diverse vascular conditions. We conclude with a discussion of barriers that must be overcome to provide enhanced insights, predictions, and decisions in pre-clinical and clinical applications.

  8. Critical Exponents of Strongly Correlated Fermion Systems from Diagrammatic Multi-Scale Methods

    NASA Astrophysics Data System (ADS)

    Antipov, Andrey; Kirchner, Stefan; Gull, Emanuel

    2014-03-01

    The dynamical mean field theory (DMFT) has become the standard tool in describing strongly correlated electron materials. While it captures the quantum dynamics of local fields, it neglects spatial correlations. To describe e.g. anti-ferromagnetism, unconventional superconductivity or frustration a proper treatment of non-local correlations is necessary. Diagrammatic multi-scale approaches offer an elegant option to accomplish this: the difficult correlated part of the system is solved using a non-perturbative many-body method, whereas 'easier', 'weakly correlated' parts of the problem are tackled using a secondary perturbative scheme. Here we employ such a method, the dual fermion approach, to problems of charge ordering in Falicov-Kimball model by constructing a systematic diagrammatic extension on top of DMFT. Near the critical point of the Falicov-Kimball model we study the interplay between charge excitations and long-range fluctuations. We show that such multi-scale approach is indeed capable of capturing the non mean-field nature of the critical point of the lattice model and correctly describes the transition to mean-field like behavior as the number of spatial dimensions increases.

  9. Method for characterization of the redox condition of cementitious materials

    SciTech Connect

    Almond, Philip M.; Langton, Christine A.; Stefanko, David B.

    2015-12-22

    Disclosed are methods for determining the redox condition of cementitious materials. The methods are leaching methods that utilize an in situ redox indicator that is present in the cementitious materials as formed. The in situ redox indicator leaches from cementitious material and, when the leaching process is carried out under anaerobic conditions can be utilized to determine the redox condition of the material. The in situ redox indicator can exhibit distinct characteristics in the leachate depending upon the redox condition of the indicator.

  10. APPLICATION OF THE MODELS-3 COMMUNITY MULTI-SCALE AIR QUALITY (CMAQ) MODEL SYSTEM TO SOS/NASHVILLE 1999

    EPA Science Inventory

    The Models-3 Community Multi-scale Air Quality (CMAQ) model, first released by the USEPA in 1999 (Byun and Ching. 1999), continues to be developed and evaluated. The principal components of the CMAQ system include a comprehensive emission processor known as the Sparse Matrix O...

  11. Nanoscale characterization of engineered cementitious composites (ECC)

    SciTech Connect

    Sakulich, Aaron Richard Li, Victor C.

    2011-02-15

    Engineered cementitious composites (ECC) are ultra-ductile fiber-reinforced cementitious composites. The nanoscale chemical and mechanical properties of three ECC formulae (one standard formula, and two containing nanomaterial additives) were studied using nanoindentation, electron microscopy, and energy dispersive spectroscopy. Nanoindentation results highlight the difference in modulus between bulk matrix ({approx} 30 GPa) and matrix/fiber interfacial transition zones as well as between matrix and unreacted fly ash ({approx} 20 GPa). The addition of carbon black or carbon nanotubes produced little variation in moduli when compared to standard M45-ECC. The indents were observed by electron microscopy; no trace of the carbon black particles could be found, but nanotubes, including nanotubes bridging cracks, were easily located in ultrafine cracks near PVA fibers. Elemental analysis failed to show a correlation between modulus and chemical composition, implying that factors such as porosity have more of an effect on mechanical properties than elemental composition.

  12. Multiscale Modeling of Nano-scale Phenomena: Towards a Multiphysics Simulation Capability for Design and Optimization of Sensor Systems

    SciTech Connect

    Becker, R; McElfresh, M; Lee, C; Balhorn, R; White, D

    2003-12-01

    In this white paper, a road map is presented to establish a multiphysics simulation capability for the design and optimization of sensor systems that incorporate nanomaterials and technologies. The Engineering Directorate's solid/fluid mechanics and electromagnetic computer codes will play an important role in both multiscale modeling and integration of required physics issues to achieve a baseline simulation capability. Molecular dynamic simulations performed primarily in the BBRP, CMS and PAT directorates, will provide information for the construction of multiscale models. All of the theoretical developments will require closely coupled experimental work to develop material models and validate simulations. The plan is synergistic and complimentary with the Laboratory's emerging core competency of multiscale modeling. The first application of the multiphysics computer code is the simulation of a ''simple'' biological system (protein recognition utilizing synthesized ligands) that has a broad range of applications including detection of biological threats, presymptomatic detection of illnesses, and drug therapy. While the overall goal is to establish a simulation capability, the near-term work is mainly focused on (1) multiscale modeling, i.e., the development of ''continuum'' representations of nanostructures based on information from molecular dynamics simulations and (2) experiments for model development and validation. A list of LDRDER proposals and ongoing projects that could be coordinated to achieve these near-term objectives and demonstrate the feasibility and utility of a multiphysics simulation capability is given.

  13. Strategies for efficient numerical implementation of hybrid multi-scale agent-based models to describe biological systems

    PubMed Central

    Cilfone, Nicholas A.; Kirschner, Denise E.; Linderman, Jennifer J.

    2015-01-01

    Biologically related processes operate across multiple spatiotemporal scales. For computational modeling methodologies to mimic this biological complexity, individual scale models must be linked in ways that allow for dynamic exchange of information across scales. A powerful methodology is to combine a discrete modeling approach, agent-based models (ABMs), with continuum models to form hybrid models. Hybrid multi-scale ABMs have been used to simulate emergent responses of biological systems. Here, we review two aspects of hybrid multi-scale ABMs: linking individual scale models and efficiently solving the resulting model. We discuss the computational choices associated with aspects of linking individual scale models while simultaneously maintaining model tractability. We demonstrate implementations of existing numerical methods in the context of hybrid multi-scale ABMs. Using an example model describing Mycobacterium tuberculosis infection, we show relative computational speeds of various combinations of numerical methods. Efficient linking and solution of hybrid multi-scale ABMs is key to model portability, modularity, and their use in understanding biological phenomena at a systems level. PMID:26366228

  14. VARIABILITY OF KD VALUES IN CEMENTITIOUS MATERIALS AND SEDIMENTS

    SciTech Connect

    Almond, P.; Kaplan, D.; Shine, E.

    2012-02-02

    Measured distribution coefficients (K{sub d} values) for environmental contaminants provide input data for performance assessments (PA) that evaluate physical and chemical phenomena for release of radionuclides from wasteforms, degradation of engineered components and subsequent transport of radionuclides through environmental media. Research efforts at SRNL to study the effects of formulation and curing variability on the physiochemical properties of the saltstone wasteform produced at the Saltstone Disposal Facility (SDF) are ongoing and provide information for the PA and Saltstone Operations. Furthermore, the range and distribution of plutonium K{sub d} values in soils is not known. Knowledge of these parameters is needed to provide guidance for stochastic modeling in the PA. Under the current SRS liquid waste processing system, supernate from F & H Tank Farm tanks is processed to remove actinides and fission products, resulting in a low-curie Decontaminated Salt Solution (DSS). At the Saltstone Production Facility (SPF), DSS is mixed with premix, comprised of blast furnace slag (BFS), Class F fly ash (FA), and portland cement (OPC) to form a grout mixture. The fresh grout is subsequently placed in SDF vaults where it cures through hydration reactions to produce saltstone, a hardened monolithic waste form. Variation in saltstone composition and cure conditions of grout can affect the saltstone's physiochemical properties. Variations in properties may originate from variables in DSS, premix, and water to premix ratio, grout mixing, placing, and curing conditions including time and temperature (Harbour et al. 2007; Harbour et al. 2009). There are no previous studies reported in the literature regarding the range and distribution of K{sub d} values in cementitious materials. Presently, the Savannah River Site (SRS) estimate ranges and distributions of K{sub d} values based on measurements of K{sub d} values made in sandy SRS sediments (Kaplan 2010). The actual

  15. Multiscale model of the human cardiovascular system: Description of heart failure and comparison of contractility indices.

    PubMed

    Kosta, S; Negroni, J; Lascano, E; Dauby, P C

    2017-02-01

    A multiscale model of the cardiovascular system is presented. Hemodynamics is described by a lumped parameter model, while heart contraction is described at the cellular scale. An electrophysiological model and a mechanical model were coupled and adjusted so that the pressure and volume of both ventricles are linked to the force and length of a half-sarcomere. Particular attention was paid to the extreme values of the sarcomere length, which must keep physiological values. This model is able to reproduce healthy behavior, preload variations experiments, and ventricular failure. It also allows to compare the relevance of standard cardiac contractility indices. This study shows that the theoretical gold standard for assessing cardiac contractility, namely the end-systolic elastance, is actually load-dependent and therefore not a reliable index of cardiac contractility.

  16. Critical exponents of strongly correlated fermion systems from diagrammatic multiscale methods.

    PubMed

    Antipov, Andrey E; Gull, Emanuel; Kirchner, Stefan

    2014-06-06

    Self-consistent dynamical approximations for strongly correlated fermion systems are particularly successful in capturing the dynamical competition of local correlations. In these, the effect of spatially extended degrees of freedom is usually only taken into account in a mean field fashion or as a secondary effect. As a result, critical exponents associated with phase transitions have a mean field character. Here we demonstrate that diagrammatic multiscale methods anchored around local approximations are indeed capable of capturing the non-mean-field nature of the critical point of the lattice model encoded in a nonvanishing anomalous dimension and of correctly describing the transition to mean-field-like behavior as the number of spatial dimensions increases.

  17. Multiscale bloom dynamics from a high frequency autonomous measurement system in the Eastern English Channel

    NASA Astrophysics Data System (ADS)

    Derot, Jonathan; Schmitt, François; Gentilhomme, Valérie

    2014-05-01

    We consider here a dataset from an Eulerian automated system, located on the coastal area of the French side of the English Channel (Boulogne-sur-Mer), called MAREL Carnot, operated by IFREMER (France). This system records more than 15 physico-chemical parameters at 20 minutes intervals, and at the constant depth of -1,5m whatever the tidal range. Our study focuses on the period 2004 to 2011. The objective of this study is to have a better understanding of the bloom fluorescence multiscale dynamics, as regards the coastal area of English Channel and possible influence of temperature on this dynamics. Annual blooms are visible, superposed to multiscale fluctuations. The probability density function (PDF) of the fluorescence time series very nicely obeys a power law with slope -2. The PDF for annual portions obeys also power laws, with slopes which are related to the annual average. Empirical mode decomposition (EMD) is used to study the dynamics and display the power spectrum, which will be linked with these dynamics. EMD method is also used to extract a trend and isolate the blooms from the high frequency dynamics. We show that the high frequency part of the fluorescence dynamics has a very large variance during bloom events, compared to normal conditions. We also show that there is a link between the mean winter temperature and the strength of bloom next spring. These results contribute to statistically characterize the bloom dynamics and extract some possible universal relations. Keywords: English Channel; Autonomous monitoring; Power spectra; EMD method; Probability density functions; Power laws.

  18. Non-cementitious compositions comprising vaterite and methods thereof

    DOEpatents

    Devenney, Martin; Fernandez, Miguel; Morgan, Samuel O.

    2015-09-15

    Non-cementitious compositions and products are provided. The compositions of the invention include a carbonate additive comprising vaterite such as reactive vaterite. Additional aspects of the invention include methods of making and using the non-cementitious compositions and products.

  19. A global multiscale mathematical model for the human circulation with emphasis on the venous system.

    PubMed

    Müller, Lucas O; Toro, Eleuterio F

    2014-07-01

    We present a global, closed-loop, multiscale mathematical model for the human circulation including the arterial system, the venous system, the heart, the pulmonary circulation and the microcirculation. A distinctive feature of our model is the detailed description of the venous system, particularly for intracranial and extracranial veins. Medium to large vessels are described by one-dimensional hyperbolic systems while the rest of the components are described by zero-dimensional models represented by differential-algebraic equations. Robust, high-order accurate numerical methodology is implemented for solving the hyperbolic equations, which are adopted from a recent reformulation that includes variable material properties. Because of the large intersubject variability of the venous system, we perform a patient-specific characterization of major veins of the head and neck using MRI data. Computational results are carefully validated using published data for the arterial system and most regions of the venous system. For head and neck veins, validation is carried out through a detailed comparison of simulation results against patient-specific phase-contrast MRI flow quantification data. A merit of our model is its global, closed-loop character; the imposition of highly artificial boundary conditions is avoided. Applications in mind include a vast range of medical conditions. Of particular interest is the study of some neurodegenerative diseases, whose venous haemodynamic connection has recently been identified by medical researchers.

  20. Analyzing the Multi-scale Interactions of Tropical Waves and Tropical Cyclone Formation with the NASA CMAVis System

    NASA Astrophysics Data System (ADS)

    Shen, B.; Nelson, B.; Tao, W.

    2011-12-01

    Among the scenarios in the Decadal Survey (DS) Missions, the advanced data processing group at the ESTO AIST PI workshop identified "Extreme Event Warning" and "Climate Projections" as two of the top priority scenarios. Recently, we (e.g., Shen et al., 2010a,b; 2011a,b) have made attempt of addressing the first by successfully developing the NASA Coupled Advanced global multiscale Modeling and concurrent Visualization systems (CAMVis) on NASA supercomputers, and demonstrating a great potential for extending the lead time (from 5~7 days up to 20 days) of tropical cyclone (TC) prediction with improved multi-scale interactions between a TC with large-scale environmental conditions such as African Easterly Waves (AEWs), and Madden Julian Oscillation (MJOs). In order to increase our confidence in long-term TC prediction and thus TC climate projection, the predictive relationships between large-scale tropical waves and TC formation need to be further examined and verified with massive model and satellite data sets. To achieve this goal, we have conducted multiscale analysis to study the TC genesis processes, accompanied downscaling (from large-scale events) and upscaling (from small-scale events) processes, and their subsequent non-linear interactions. In this study, we first illustrate the complicated multi-scale interactions during TC genesis with our newly-developed 3D streamline packages in the NASA CAMVis system. With selected cases that include twin TCs in 2002, TC Nargis (2008) and hurricane Helene (2006), we will show that the CAMVis can provide a detailed (zoomed-in) view on hurricane physical processes and an integrative (zoomed-out) view on its interactions with environmental conditions. In the end of talk, we will discuss our future work in multiscale analysis with the Hilbert Huang Transform and improved ensemble empiric mode decomposition.

  1. Innovative Structural Materials and Sections with Strain Hardening Cementitious Composites

    NASA Astrophysics Data System (ADS)

    Dey, Vikram

    The motivation of this work is based on development of new construction products with strain hardening cementitious composites (SHCC) geared towards sustainable residential applications. The proposed research has three main objectives: automation of existing manufacturing systems for SHCC laminates; multi-level characterization of mechanical properties of fiber, matrix, interface and composites phases using servo-hydraulic and digital image correlation techniques. Structural behavior of these systems were predicted using ductility based design procedures using classical laminate theory and structural mechanics. SHCC sections are made up of thin sections of matrix with Portland cement based binder and fine aggregates impregnating continuous one-dimensional fibers in individual or bundle form or two/three dimensional woven, bonded or knitted textiles. Traditional fiber reinforced concrete (FRC) use random dispersed chopped fibers in the matrix at a low volume fractions, typically 1-2% to avoid to avoid fiber agglomeration and balling. In conventional FRC, fracture localization occurs immediately after the first crack, resulting in only minor improvement in toughness and tensile strength. However in SHCC systems, distribution of cracking throughout the specimen is facilitated by the fiber bridging mechanism. Influence of material properties of yarn, composition, geometry and weave patterns of textile in the behavior of laminated SHCC skin composites were investigated. Contribution of the cementitious matrix in the early age and long-term performance of laminated composites was studied with supplementary cementitious materials such as fly ash, silica fume, and wollastonite. A closed form model with classical laminate theory and ply discount method, coupled with a damage evolution model was utilized to simulate the non-linear tensile response of these composite materials. A constitutive material model developed earlier in the group was utilized to characterize and

  2. Training Systems Modelers through the Development of a Multi-scale Chagas Disease Risk Model

    NASA Astrophysics Data System (ADS)

    Hanley, J.; Stevens-Goodnight, S.; Kulkarni, S.; Bustamante, D.; Fytilis, N.; Goff, P.; Monroy, C.; Morrissey, L. A.; Orantes, L.; Stevens, L.; Dorn, P.; Lucero, D.; Rios, J.; Rizzo, D. M.

    2012-12-01

    The goal of our NSF-sponsored Division of Behavioral and Cognitive Sciences grant is to create a multidisciplinary approach to develop spatially explicit models of vector-borne disease risk using Chagas disease as our model. Chagas disease is a parasitic disease endemic to Latin America that afflicts an estimated 10 million people. The causative agent (Trypanosoma cruzi) is most commonly transmitted to humans by blood feeding triatomine insect vectors. Our objectives are: (1) advance knowledge on the multiple interacting factors affecting the transmission of Chagas disease, and (2) provide next generation genomic and spatial analysis tools applicable to the study of other vector-borne diseases worldwide. This funding is a collaborative effort between the RSENR (UVM), the School of Engineering (UVM), the Department of Biology (UVM), the Department of Biological Sciences (Loyola (New Orleans)) and the Laboratory of Applied Entomology and Parasitology (Universidad de San Carlos). Throughout this five-year study, multi-educational groups (i.e., high school, undergraduate, graduate, and postdoctoral) will be trained in systems modeling. This systems approach challenges students to incorporate environmental, social, and economic as well as technical aspects and enables modelers to simulate and visualize topics that would either be too expensive, complex or difficult to study directly (Yasar and Landau 2003). We launch this research by developing a set of multi-scale, epidemiological models of Chagas disease risk using STELLA® software v.9.1.3 (isee systems, inc., Lebanon, NH). We use this particular system dynamics software as a starting point because of its simple graphical user interface (e.g., behavior-over-time graphs, stock/flow diagrams, and causal loops). To date, high school and undergraduate students have created a set of multi-scale (i.e., homestead, village, and regional) disease models. Modeling the system at multiple spatial scales forces recognition that

  3. Progression to multi-scale models and the application to food system intervention strategies.

    PubMed

    Gröhn, Yrjö T

    2015-02-01

    The aim of this article is to discuss how the systems science approach can be used to optimize intervention strategies in food animal systems. It advocates the idea that the challenges of maintaining a safe food supply are best addressed by integrating modeling and mathematics with biological studies critical to formulation of public policy to address these challenges. Much information on the biology and epidemiology of food animal systems has been characterized through single-discipline methods, but until now this information has not been thoroughly utilized in a fully integrated manner. The examples are drawn from our current research. The first, explained in depth, uses clinical mastitis to introduce the concept of dynamic programming to optimize management decisions in dairy cows (also introducing the curse of dimensionality problem). In the second example, a compartmental epidemic model for Johne's disease with different intervention strategies is optimized. The goal of the optimization strategy depends on whether there is a relationship between Johne's and Crohn's disease. If so, optimization is based on eradication of infection; if not, it is based on the cow's performance only (i.e., economic optimization, similar to the mastitis example). The third example focuses on food safety to introduce risk assessment using Listeria monocytogenes and Salmonella Typhimurium. The last example, practical interventions to effectively manage antibiotic resistance in beef and dairy cattle systems, introduces meta-population modeling that accounts for bacterial growth not only in the host (cow), but also in the cow's feed, drinking water and the housing environment. Each example stresses the need to progress toward multi-scale modeling. The article ends with examples of multi-scale systems, from food supply systems to Johne's disease. Reducing the consequences of foodborne illnesses (i.e., minimizing disease occurrence and associated costs) can only occur through an

  4. Property investigation of calcium–silicate–hydrate (C–S–H) gel in cementitious composites

    SciTech Connect

    Hu, Chuanlin; Han, Yunge; Gao, Yueyi; Zhang, Yamei; Li, Zongjin

    2014-09-15

    Calcium–silicate–hydrate (C–S–H) gel, the main product of cement hydration, contributes the most to engineering properties of concrete. Hence, the microstructural physical and mechanical properties of C–S–H gel present in cementitious composites were investigated by the coupled nanoindentation and scanning electron microscope analysis. The physical and mechanical properties were linked through the micro-poromechanical approach. Through this study, an insight was provided into the microstructural features of C–S–H gel present in cementitious composites. It is found that C–S–H gel is a multi-scale composite composed of C–S–H solid, pore and intermixtures at the scale of nanoindentation on C–S–H gel, and the physical and mechanical properties of C–S–H gel can be influenced by the porosity and volume fraction of the intermixtures. - Highlights: • A coupled nanoindentation and scanning electron microscope technique was applied. • The physical and mechanical properties were linked by the proposed model. • The porosity and poroelastic parameters were reported for the first time. • The influence of water to cement ratio was studied.

  5. Adaptive Multi-scale Prognostics and Health Management for Smart Manufacturing Systems

    PubMed Central

    Choo, Benjamin Y.; Adams, Stephen C.; Weiss, Brian A.; Marvel, Jeremy A.; Beling, Peter A.

    2017-01-01

    The Adaptive Multi-scale Prognostics and Health Management (AM-PHM) is a methodology designed to enable PHM in smart manufacturing systems. In application, PHM information is not yet fully utilized in higher-level decision-making in manufacturing systems. AM-PHM leverages and integrates lower-level PHM information such as from a machine or component with hierarchical relationships across the component, machine, work cell, and assembly line levels in a manufacturing system. The AM-PHM methodology enables the creation of actionable prognostic and diagnostic intelligence up and down the manufacturing process hierarchy. Decisions are then made with the knowledge of the current and projected health state of the system at decision points along the nodes of the hierarchical structure. To overcome the issue of exponential explosion of complexity associated with describing a large manufacturing system, the AM-PHM methodology takes a hierarchical Markov Decision Process (MDP) approach into describing the system and solving for an optimized policy. A description of the AM-PHM methodology is followed by a simulated industry-inspired example to demonstrate the effectiveness of AM-PHM. PMID:28736651

  6. Multi-Scale Three-Dimensional Variational Data Assimilation System for Coastal Ocean Prediction

    NASA Technical Reports Server (NTRS)

    Li, Zhijin; Chao, Yi; Li, P. Peggy

    2012-01-01

    A multi-scale three-dimensional variational data assimilation system (MS-3DVAR) has been formulated and the associated software system has been developed for improving high-resolution coastal ocean prediction. This system helps improve coastal ocean prediction skill, and has been used in support of operational coastal ocean forecasting systems and field experiments. The system has been developed to improve the capability of data assimilation for assimilating, simultaneously and effectively, sparse vertical profiles and high-resolution remote sensing surface measurements into coastal ocean models, as well as constraining model biases. In this system, the cost function is decomposed into two separate units for the large- and small-scale components, respectively. As such, data assimilation is implemented sequentially from large to small scales, the background error covariance is constructed to be scale-dependent, and a scale-dependent dynamic balance is incorporated. This scheme then allows effective constraining large scales and model bias through assimilating sparse vertical profiles, and small scales through assimilating high-resolution surface measurements. This MS-3DVAR enhances the capability of the traditional 3DVAR for assimilating highly heterogeneously distributed observations, such as along-track satellite altimetry data, and particularly maximizing the extraction of information from limited numbers of vertical profile observations.

  7. Stochastic and deterministic multiscale models for systems biology: an auxin-transport case study.

    PubMed

    Twycross, Jamie; Band, Leah R; Bennett, Malcolm J; King, John R; Krasnogor, Natalio

    2010-03-26

    Stochastic and asymptotic methods are powerful tools in developing multiscale systems biology models; however, little has been done in this context to compare the efficacy of these methods. The majority of current systems biology modelling research, including that of auxin transport, uses numerical simulations to study the behaviour of large systems of deterministic ordinary differential equations, with little consideration of alternative modelling frameworks. In this case study, we solve an auxin-transport model using analytical methods, deterministic numerical simulations and stochastic numerical simulations. Although the three approaches in general predict the same behaviour, the approaches provide different information that we use to gain distinct insights into the modelled biological system. We show in particular that the analytical approach readily provides straightforward mathematical expressions for the concentrations and transport speeds, while the stochastic simulations naturally provide information on the variability of the system. Our study provides a constructive comparison which highlights the advantages and disadvantages of each of the considered modelling approaches. This will prove helpful to researchers when weighing up which modelling approach to select. In addition, the paper goes some way to bridging the gap between these approaches, which in the future we hope will lead to integrative hybrid models.

  8. Multi-scale spectrally resolved quantitative fluorescence imaging system: towards neurosurgical guidance in glioma resection

    NASA Astrophysics Data System (ADS)

    Xie, Yijing; Thom, Maria; Miserocchi, Anna; McEvoy, Andrew W.; Desjardins, Adrien; Ourselin, Sebastien; Vercauteren, Tom

    2017-02-01

    In glioma resection surgery, the detection of tumour is often guided by using intraoperative fluorescence imaging notably with 5-ALA-PpIX, providing fluorescent contrast between normal brain tissue and the gliomas tissue to achieve improved tumour delineation and prolonged patient survival compared with the conventional white-light guided resection. However, the commercially available fluorescence imaging system relies on surgeon's eyes to visualise and distinguish the fluorescence signals, which unfortunately makes the resection subjective. In this study, we developed a novel multi-scale spectrally-resolved fluorescence imaging system and a computational model for quantification of PpIX concentration. The system consisted of a wide-field spectrally-resolved quantitative imaging device and a fluorescence endomicroscopic imaging system enabling optical biopsy. Ex vivo animal tissue experiments as well as human tumour sample studies demonstrated that the system was capable of specifically detecting the PpIX fluorescent signal and estimate the true concentration of PpIX in brain specimen.

  9. Stochastic and deterministic multiscale models for systems biology: an auxin-transport case study

    PubMed Central

    2010-01-01

    Background Stochastic and asymptotic methods are powerful tools in developing multiscale systems biology models; however, little has been done in this context to compare the efficacy of these methods. The majority of current systems biology modelling research, including that of auxin transport, uses numerical simulations to study the behaviour of large systems of deterministic ordinary differential equations, with little consideration of alternative modelling frameworks. Results In this case study, we solve an auxin-transport model using analytical methods, deterministic numerical simulations and stochastic numerical simulations. Although the three approaches in general predict the same behaviour, the approaches provide different information that we use to gain distinct insights into the modelled biological system. We show in particular that the analytical approach readily provides straightforward mathematical expressions for the concentrations and transport speeds, while the stochastic simulations naturally provide information on the variability of the system. Conclusions Our study provides a constructive comparison which highlights the advantages and disadvantages of each of the considered modelling approaches. This will prove helpful to researchers when weighing up which modelling approach to select. In addition, the paper goes some way to bridging the gap between these approaches, which in the future we hope will lead to integrative hybrid models. PMID:20346112

  10. Tailoring engineered cementitious composites for impact resistance

    SciTech Connect

    Yang, En-Hua; Li, Victor C.

    2012-08-15

    This paper presents results of deliberate tailoring of engineered cementitious composites (ECC) for impact resistance. Microstructure control involving fiber, matrix and fiber/matrix interface was based on steady-state dynamic crack growth analyses accounting for rate dependence of composite phases. Uniaxial tensile stress-strain curves of the resulting impact resistant ECC were experimentally determined for strain rates ranging from 10{sup -5} s{sup -1} to 10{sup -1} s{sup -1}. Low speed drop weight tower test on ECC panels and beams was also conducted. Damage characteristics, load and energy dissipation capacities, and response to repeated impacts, were studied.

  11. ESPResSo++: A modern multiscale simulation package for soft matter systems

    NASA Astrophysics Data System (ADS)

    Halverson, Jonathan D.; Brandes, Thomas; Lenz, Olaf; Arnold, Axel; Bevc, Staš; Starchenko, Vitaliy; Kremer, Kurt; Stuehn, Torsten; Reith, Dirk

    2013-04-01

    The redesigned Extensible Simulation Package for Research on Soft matter systems (ESPResSo++) is a free, open-source, parallelized, object-oriented simulation package designed to perform many-particle simulations, principally molecular dynamics and Monte Carlo, of condensed soft matter systems. In addition to the standard simulation methods found in well-established packages, ESPResSo++ provides the ability to perform Adaptive Resolution Scheme (AdResS) simulations which are multiscale simulations of molecular systems where the level of resolution of each molecule can change on-the-fly. With the main design objective being extensibility, the software features a highly modular C++ kernel that is coupled to a Python user interface. This makes it easy to add new algorithms, setup a simulation, perform online analysis, use complex workflows and steer a simulation. The extreme flexibility of the software allows for the study of a wide range of systems. The modular structure enables scientists to use ESPResSo++ as a research platform for their own methodological developments, which at the same time allows the software to grow and acquire the most modern methods. ESPResSo++ is targeted for a broad range of architectures and is licensed under the GNU General Public License.

  12. Poincaré-Treshchev Mechanism in Multi-scale, Nearly Integrable Hamiltonian Systems

    NASA Astrophysics Data System (ADS)

    Xu, Lu; Li, Yong; Yi, Yingfei

    2017-08-01

    This paper is a continuation to our work (Xu et al. in Ann Henri Poincaré 18(1):53-83, 2017) concerning the persistence of lower-dimensional tori on resonant surfaces of a multi-scale, nearly integrable Hamiltonian system. This type of systems, being properly degenerate, arise naturally in planar and spatial lunar problems of celestial mechanics for which the persistence problem ties closely to the stability of the systems. For such a system, under certain non-degenerate conditions of Rüssmann type, the majority persistence of non-resonant tori and the existence of a nearly full measure set of Poincaré non-degenerate, lower-dimensional, quasi-periodic invariant tori on a resonant surface corresponding to the highest order of scale is proved in Han et al. (Ann Henri Poincaré 10(8):1419-1436, 2010) and Xu et al. (2017), respectively. In this work, we consider a resonant surface corresponding to any intermediate order of scale and show the existence of a nearly full measure set of Poincaré non-degenerate, lower-dimensional, quasi-periodic invariant tori on the resonant surface. The proof is based on a normal form reduction which consists of a finite step of KAM iterations in pushing the non-integrable perturbation to a sufficiently high order and the splitting of resonant tori on the resonant surface according to the Poincaré-Treshchev mechanism.

  13. Coarse analysis of multiscale systems: Diffuser flows, charged particle motion, and connections to averaging theory

    NASA Astrophysics Data System (ADS)

    Fung, Jimmy

    We describe a technique for the efficient computation of the dominant-scale dynamics of a fluid system when only a high-fidelity simulation is available. Such a technique is desirable when governing equations for the dominant scales are unavailable, when model reduction is impractical, or when the original high-fidelity computation is expensive. We adopt the coarse analysis framework proposed by I. G. Kevrekidis (Comm. Math. Sci. 2003), where a computational superstructure is designed to use short-time, high-fidelity simulations to extract the dominant features for a multiscale system. We apply this technique to compute the dominant features of the compressible flow through a planar diffuser. We apply the proper orthogonal decomposition to classify the dominant and subdominant scales of diffuser flows. We derive a coarse projective Adams-Bashforth time integration routine and compute averaged diffuser flows. The results include accurate tracking of the dominant-scale dynamics for a range of parameter values for the computational superstructure. These results demonstrate that coarse analysis methods are useful for solving fluid flow problems of a multiscale nature. In order to elucidate the behavior of coarse analysis techniques, we make comparisons to averaging theory. To this end, we derive governing equations for the average motion of charged particles in a magnetic field in a number of different settings. First, we apply a novel procedure, inspired by WKB theory and Whitham averaging, to average the variational principle. The resulting equations are equivalent to the guiding center equations for charged particle motion; this marks an instance where averaging and variational principles commute. Secondly, we apply Lagrangian averaging techniques, previously applied in fluid mechanics, to derive averaged equations. Making comparisons to the WKB/Whitham derivation allows for the necessary closure of the Lagrangian averaging formulation. We also discuss the

  14. Global Positioning System Navigation Above 76,000 km for NASA's Magnetospheric Multiscale Mission

    NASA Technical Reports Server (NTRS)

    Winternitz, Luke B.; Bamford, William A.; Price, Samuel R.; Carpenter, J. Russell; Long, Anne C.; Farahmand, Mitra

    2016-01-01

    NASA's Magnetospheric Multiscale (MMS) mission, launched in March of 2015, consists of a controlled formation of four spin-stabilized spacecraft in similar highly elliptic orbits reaching apogee at radial distances of 12 and 25 Earth radii (RE) in the first and second phases of the mission. Navigation for MMSis achieved independently on-board each spacecraft by processing Global Positioning System (GPS) observables using NASA Goddard Space Flight Center (GSFC)'s Navigator GPS receiver and the Goddard Enhanced Onboard Navigation System (GEONS) extended Kalman filter software. To our knowledge, MMS constitutes, by far, the highest-altitude operational use of GPS to date and represents a high point of over a decade of high-altitude GPS navigation research and development at GSFC. In this paper we will briefly describe past and ongoing high-altitude GPS research efforts at NASA GSFC and elsewhere, provide details on the design of the MMS GPS navigation system, and present on-orbit performance data from the first phase. We extrapolate these results to predict performance in the second phase orbit, and conclude with a discussion of the implications of the MMS results for future high-altitude GPS navigation, which we believe to be broad and far-reaching.

  15. Global Positioning System Navigation Above 76,000 km for NASA's Magnetospheric Multiscale Mission

    NASA Technical Reports Server (NTRS)

    Winternitz, Luke B.; Bamford, William A.; Price, Samuel R.; Carpenter, J. Russell; Long, Anne C.; Farahmand, Mitra

    2016-01-01

    NASA's Magnetospheric Multiscale (MMS) mission, launched in March of 2015, consists of a controlled formation of four spin-stabilized spacecraft in similar highly elliptic orbits reaching apogee at radial distances of 12 and 25 Earth radii (RE) in the first and second phases of the mission. Navigation for MMS is achieved independently on-board each spacecraft by processing Global Positioning System (GPS) observables using NASA Goddard Space Flight Center (GSFC)'s Navigator GPS receiver and the Goddard Enhanced Onboard Navigation System (GEONS) extended Kalman filter software. To our knowledge, MMS constitutes, by far, the highest-altitude operational use of GPS to date and represents a high point of over a decade of high-altitude GPS navigation research and development at GSFC. In this paper we will briefly describe past and ongoing high-altitude GPS research efforts at NASA GSFC and elsewhere, provide details on the design of the MMS GPS navigation system, and present on-orbit performance data from the first phase. We extrapolate these results to predict performance in the second phase orbit, and conclude with a discussion of the implications of the MMS results for future high-altitude GPS navigation, which we believe to be broad and far-reaching.

  16. CHEMDNER system with mixed conditional random fields and multi-scale word clustering.

    PubMed

    Lu, Yanan; Ji, Donghong; Yao, Xiaoyuan; Wei, Xiaomei; Liang, Xiaohui

    2015-01-01

    The chemical compound and drug name recognition plays an important role in chemical text mining, and it is the basis for automatic relation extraction and event identification in chemical information processing. So a high-performance named entity recognition system for chemical compound and drug names is necessary. We developed a CHEMDNER system based on mixed conditional random fields (CRF) with word clustering for chemical compound and drug name recognition. For the word clustering, we used Brown's hierarchical algorithm and Skip-gram model based on deep learning with massive PubMed articles including titles and abstracts. This system achieved the highest F-score of 88.20% for the CDI task and the second highest F-score of 87.11% for the CEM task in BioCreative IV. The performance was further improved by multi-scale clustering based on deep learning, achieving the F-score of 88.71% for CDI and 88.06% for CEM. The mixed CRF model represents both the internal complexity and external contexts of the entities, and the model is integrated with word clustering to capture domain knowledge with PubMed articles including titles and abstracts. The domain knowledge helps to ensure the performance of the entity recognition, even without fine-grained linguistic features and manually designed rules.

  17. Study on multi-scale blending initial condition perturbations for a regional ensemble prediction system

    NASA Astrophysics Data System (ADS)

    Zhang, Hanbin; Chen, Jing; Zhi, Xiefei; Wang, Yi; Wang, Yanan

    2015-08-01

    An initial conditions (ICs) perturbation method was developed with the aim to improve an operational regional ensemble prediction system (REPS). Three issues were identified and investigated: (1) the impacts of perturbation scale on the ensemble spread and forecast skill of the REPS; (2) the scale characteristic of the IC perturbations of the REPS; and (3) whether the REPS's skill could be improved by adding large-scale information to the IC perturbations. Numerical experiments were conducted to reveal the impact of perturbation scale on the ensemble spread and forecast skill. The scales of IC perturbations from the REPS and an operational global ensemble prediction system (GEPS) were analyzed. A "multi-scale blending" (MSB) IC perturbation scheme was developed, and the main findings can be summarized as follows: The growth rates of the ensemble spread of the REPS are sensitive to the scale of the IC perturbations; the ensemble forecast skills can benefit from large-scale perturbations; the global ensemble IC perturbations exhibit more power at larger scales, while the regional ensemble IC perturbations contain more power at smaller scales; the MSB method can generate IC perturbations by combining the small-scale component from the REPS and the large-scale component from the GEPS; the energy norm growth of the MSB-generated perturbations can be appropriate at all forecast lead times; and the MSB-based REPS shows higher skill than the original system, as determined by ensemble forecast verification.

  18. Multi-scale features in recent development of enzymic biocatalyst systems.

    PubMed

    Wang, Ping

    2009-02-01

    Functional relation among elements of different size scales in a system is probably a main challenge across the areas of the science of engineering ever since their emergence. Multi-scale time and size correlation for description and prediction of complex systems, however, has been systematically examined only recently with the aid of new computational tools. In the pursuit of efficient and sustainable chemical processing technologies, people have seen a growing emphasis on synthetic biotechnology in recent R&D efforts. In particular, industrial enzyme technologies are attracting enormous attention. Having been traditionally developed for food and detergent applications, industrial enzyme technologies are being re-examined and tested to their limits to keep abreast of the challenges in drug, biochemical, and the emerging biorenewable energy industries. Toward that, enzymes are required to function in non-conventional conditions, such as organic solvents, extreme pH, and temperatures; they also have to compete against alternative chemical technologies in terms of costs and efficiency. Accordingly, enzymic biocatalyst systems are being tackled dynamically at all size levels through efforts ranging from molecular level protein engineering and modification, nanoscale structure fabrication, and microenvironment manipulation to the construction of microchip devices and macroscopic industrial bioreactors and devices. These efforts are probably still on a case-to-case trial basis without much consideration of cross-scale correlations. Discovering, understanding, and controlling of the common features that relate functions of biocatalysts at different size scales may eventually be realized in future.

  19. Good coupling for the multiscale patch scheme on systems with microscale heterogeneity

    NASA Astrophysics Data System (ADS)

    Bunder, J. E.; Roberts, A. J.; Kevrekidis, I. G.

    2017-05-01

    Computational simulation of microscale detailed systems is frequently only feasible over spatial domains much smaller than the macroscale of interest. The 'equation-free' methodology couples many small patches of microscale computations across space to empower efficient computational simulation over macroscale domains of interest. Motivated by molecular or agent simulations, we analyse the performance of various coupling schemes for patches when the microscale is inherently 'rough'. As a canonical problem in this universality class, we systematically analyse the case of heterogeneous diffusion on a lattice. Computer algebra explores how the dynamics of coupled patches predict the large scale emergent macroscale dynamics of the computational scheme. We determine good design for the coupling of patches by comparing the macroscale predictions from patch dynamics with the emergent macroscale on the entire domain, thus minimising the computational error of the multiscale modelling. The minimal error on the macroscale is obtained when the coupling utilises averaging regions which are between a third and a half of the patch. Moreover, when the symmetry of the inter-patch coupling matches that of the underlying microscale structure, patch dynamics predicts the desired macroscale dynamics to any specified order of error. The results confirm that the patch scheme is useful for macroscale computational simulation of a range of systems with microscale heterogeneity.

  20. Precision Closed-Loop Orbital Maneuvering System Design and Performance for the Magnetospheric Multiscale Formation

    NASA Technical Reports Server (NTRS)

    Chai, Dean J.; Queen, Steven Z.; Placanica, Samuel J.

    2015-01-01

    NASAs Magnetospheric Multiscale (MMS) mission successfully launched on March 13,2015 (UTC) consists of four identically instrumented spin-stabilized observatories that function as a constellation to study magnetic reconnection in space. The need to maintain sufficiently accurate spatial and temporal formation resolution of the observatories must be balanced against the logistical constraints of executing overly-frequent maneuvers on a small fleet of spacecraft. These two considerations make for an extremely challenging maneuver design problem. This paper focuses on the design elements of a 6-DOF spacecraft attitude control and maneuvering system capable of delivering the high-precision adjustments required by the constellation designers specifically, the design, implementation, and on-orbit performance of the closed-loop formation-class maneuvers that include initialization, maintenance, and re-sizing. The maneuvering control system flown on MMS utilizes a micro-gravity resolution accelerometer sampled at a high rate in order to achieve closed-loop velocity tracking of an inertial target with arc-minute directional and millimeter-per second magnitude accuracy. This paper summarizes the techniques used for correcting bias drift, sensor-head offsets, and centripetal aliasing in the acceleration measurements. It also discusses the on-board pre-maneuver calibration and compensation algorithms as well as the implementation of the post-maneuver attitude adjustments.

  1. Augmenting Surgery via Multi-scale Modeling and Translational Systems Biology in the Era of Precision Medicine: A Multidisciplinary Perspective

    PubMed Central

    Kassab, Ghassan S.; An, Gary; Sander, Edward A.; Miga, Michael; Guccione, Julius M.; Ji, Songbai; Vodovotz, Yoram

    2016-01-01

    In this era of tremendous technological capabilities and increased focus on improving clinical outcomes, decreasing costs, and increasing precision, there is a need for a more quantitative approach to the field of surgery. Multiscale computational modeling has the potential to bridge the gap to the emerging paradigms of Precision Medicine and Translational Systems Biology, in which quantitative metrics and data guide patient care through improved stratification, diagnosis, and therapy. Achievements by multiple groups have demonstrated the potential for 1) multiscale computational modeling, at a biological level, of diseases treated with surgery and the surgical procedure process at the level of the individual and the population; along with 2) patient-specific, computationally-enabled surgical planning, delivery, and guidance and robotically-augmented manipulation. In this perspective article, we discuss these concepts, and cite emerging examples from the fields of trauma, wound healing, and cardiac surgery. PMID:27015816

  2. Simulations of Tornadoes, Tropical Cyclones, MJOs, and QBOs, using GFDL's multi-scale global climate modeling system

    NASA Astrophysics Data System (ADS)

    Lin, Shian-Jiann; Harris, Lucas; Chen, Jan-Huey; Zhao, Ming

    2014-05-01

    A multi-scale High-Resolution Atmosphere Model (HiRAM) is being developed at NOAA/Geophysical Fluid Dynamics Laboratory. The model's dynamical framework is the non-hydrostatic extension of the vertically Lagrangian finite-volume dynamical core (Lin 2004, Monthly Wea. Rev.) constructed on a stretchable (via Schmidt transformation) cubed-sphere grid. Physical parametrizations originally designed for IPCC-type climate predictions are in the process of being modified and made more "scale-aware", in an effort to make the model suitable for multi-scale weather-climate applications, with horizontal resolution ranging from 1 km (near the target high-resolution region) to as low as 400 km (near the antipodal point). One of the main goals of this development is to enable simulation of high impact weather phenomena (such as tornadoes, thunderstorms, category-5 hurricanes) within an IPCC-class climate modeling system previously thought impossible. We will present preliminary results, covering a very wide spectrum of temporal-spatial scales, ranging from simulation of tornado genesis (hours), Madden-Julian Oscillations (intra-seasonal), topical cyclones (seasonal), to Quasi Biennial Oscillations (intra-decadal), using the same global multi-scale modeling system.

  3. Materials integrity in microsystems: a framework for a petascale predictive-science-based multiscale modeling and simulation system

    NASA Astrophysics Data System (ADS)

    To, Albert C.; Liu, Wing Kam; Olson, Gregory B.; Belytschko, Ted; Chen, Wei; Shephard, Mark S.; Chung, Yip-Wah; Ghanem, Roger; Voorhees, Peter W.; Seidman, David N.; Wolverton, Chris; Chen, J. S.; Moran, Brian; Freeman, Arthur J.; Tian, Rong; Luo, Xiaojuan; Lautenschlager, Eric; Challoner, A. Dorian

    2008-09-01

    Microsystems have become an integral part of our lives and can be found in homeland security, medical science, aerospace applications and beyond. Many critical microsystem applications are in harsh environments, in which long-term reliability needs to be guaranteed and repair is not feasible. For example, gyroscope microsystems on satellites need to function for over 20 years under severe radiation, thermal cycling, and shock loading. Hence a predictive-science-based, verified and validated computational models and algorithms to predict the performance and materials integrity of microsystems in these situations is needed. Confidence in these predictions is improved by quantifying uncertainties and approximation errors. With no full system testing and limited sub-system testings, petascale computing is certainly necessary to span both time and space scales and to reduce the uncertainty in the prediction of long-term reliability. This paper presents the necessary steps to develop predictive-science-based multiscale modeling and simulation system. The development of this system will be focused on the prediction of the long-term performance of a gyroscope microsystem. The environmental effects to be considered include radiation, thermo-mechanical cycling and shock. Since there will be many material performance issues, attention is restricted to creep resulting from thermal aging and radiation-enhanced mass diffusion, material instability due to radiation and thermo-mechanical cycling and damage and fracture due to shock. To meet these challenges, we aim to develop an integrated multiscale software analysis system that spans the length scales from the atomistic scale to the scale of the device. The proposed software system will include molecular mechanics, phase field evolution, micromechanics and continuum mechanics software, and the state-of-the-art model identification strategies where atomistic properties are calibrated by quantum calculations. We aim to predict the

  4. Multi-scale hydrogeological and hydrogeophysical approach to monitor vadose zone hydrodynamics of a karst system

    NASA Astrophysics Data System (ADS)

    Watlet, Arnaud; Poulain, Amaël; Van Camp, Michel; Francis, Olivier; Triantafyllou, Antoine; Rochez, Gaëtan; Hallet, Vincent; Kaufmann, Olivier

    2016-04-01

    The vadose zone of karst systems plays an important role on the water dynamics. In particular, temporary perched aquifers can appear in the subsurface due to changes of weather conditions, reduced evapotranspiration and the vertical gradients of porosity and permeability. Although many difficulties are usually encountered when studying karst environments due to their heterogeneities, cave systems offer an outstanding opportunity to investigate vadose zone from the inside. We present a multi-scale study covering two years of hydrogeological and geophysical monitoring of the Lomme Karst System (LKS) located in the Variscan fold-and-thrust belt (Belgium), a region (~ 3000 ha) that shows many karstic networks within Devonian limestone units. Hydrogeological data cover the whole LKS and involve e.g. flows and levels monitoring or tracer tests performed in both vadose and saturated zones. Such data bring valuable information on the hydrological context of the studied area at the catchment scale. Combining those results with geophysical measurements allows validating and imaging them at a smaller scale, with more integrative techniques. Hydrogeophysical measurements are focused on only one cave system of the LKS, at the Rochefort site (~ 40 ha), taking benefit of the Rochefort Cave Laboratory (RCL) infrastructures. In this study, a microgravimetric monitoring and an Electrical Resistivity Tomography (ERT) monitoring are involved. The microgravimetric monitoring consists in a superconducting gravimeter continuously measuring gravity changes at the surface of the RCL and an additional relative gravimeter installed in the underlying cave located 35 meters below the surface. While gravimeters are sensible to changes that occur in both the vadose zone and the saturated zone of the whole cave system, combining their recorded signals allows enhancing vadose zone's gravity changes. Finally, the surface ERT monitoring provide valuable information at the (sub)-meter scale on the

  5. Orbital Manuvering System Design and Performance For the Magnetosperic Multiscale Constellation

    NASA Technical Reports Server (NTRS)

    Queen, Steven Z.; Chai, Dean J.; Placanica, Sam

    2013-01-01

    The Magnetospheric Multiscale (MMS) mission, launched on March 13, 2015, is the fourth mission of NASA's Solar Terrestrial Probe program. The MMS mission consists of four identically instrumented observatories that function as a constellation to provide the first definitive study of magnetic reconnection in space. Since it is frequently desirable to isolate electric and magnetic field sensors from stray effects caused by the spacecraft's core-body, the suite of instruments on MMS includes six radial and two axial instrument-booms with deployed lengths ranging from 5-60 meters (see Figure 1). The observatory is spin-stabilized about its positive z-axis with a nominal rate slightly above 3 rev/min (RPM). The spin is also used to maintain tension in the four radial wire-booms. Each observatory's Attitude Control System (ACS) consists of digital sun sensors, star cameras, accelerometers, and mono-propellant hydrazine thrusters-responsible for orbital adjustments, attitude control, and spin adjustments. The sections that follow describe performance requirements, the hardware and algorithms used for 6-DOF estimation, and then similarly for 6-DOF control. The paper concludes with maneuver performance based on both simulated and on-orbit telem.

  6. Time-Varying, Multi-Scale Adaptive System Reliability Analysis of Lifeline Infrastructure Networks

    SciTech Connect

    Gearhart, Jared Lee; Kurtz, Nolan Scot

    2014-09-01

    The majority of current societal and economic needs world-wide are met by the existing networked, civil infrastructure. Because the cost of managing such infrastructure is high and increases with time, risk-informed decision making is essential for those with management responsibilities for these systems. To address such concerns, a methodology that accounts for new information, deterioration, component models, component importance, group importance, network reliability, hierarchical structure organization, and efficiency concerns has been developed. This methodology analyzes the use of new information through the lens of adaptive Importance Sampling for structural reliability problems. Deterioration, multi-scale bridge models, and time-variant component importance are investigated for a specific network. Furthermore, both bridge and pipeline networks are studied for group and component importance, as well as for hierarchical structures in the context of specific networks. Efficiency is the primary driver throughout this study. With this risk-informed approach, those responsible for management can address deteriorating infrastructure networks in an organized manner.

  7. Molecular systems biology of Sic1 in yeast cell cycle regulation through multiscale modeling.

    PubMed

    Barberis, Matteo

    2012-01-01

    Cell cycle control is highly regulated to guarantee the precise timing of events essential for cell growth, i.e., DNA replication onset and cell division. Failure of this control plays a role in cancer and molecules called cyclin-dependent kinase (Cdk) inhibitors (Ckis) exploit a critical function in cell cycle timing. Here we present a multiscale modeling where experimental and computational studies have been employed to investigate structure, function and temporal dynamics of the Cki Sic1 that regulates cell cycle progression in Saccharomyces cerevisiae. Structural analyses reveal molecular details of the interaction between Sic1 and Cdk/cyclin complexes, and biochemical investigation reveals Sic1 function in analogy to its human counterpart p27(Kip1), whose deregulation leads to failure in timing of kinase activation and, therefore, to cancer. Following these findings, a bottom-up systems biology approach has been developed to characterize modular networks addressing Sic1 regulatory function. Through complementary experimentation and modeling, we suggest a mechanism that underlies Sic1 function in controlling temporal waves of cyclins to ensure correct timing of the phase-specific Cdk activities.

  8. An integrated multiscale river basin observing system in the Heihe River Basin, northwest China

    NASA Astrophysics Data System (ADS)

    Li, X.; Liu, S.; Xiao, Q.; Ma, M.; Jin, R.; Che, T.

    2015-12-01

    Using the watershed as the unit to establish an integrated watershed observing system has been an important trend in integrated eco-hydrologic studies in the past ten years. Thus far, a relatively comprehensive watershed observing system has been established in the Heihe River Basin, northwest China. In addition, two comprehensive remote sensing hydrology experiments have been conducted sequentially in the Heihe River Basin, including the Watershed Allied Telemetry Experimental Research (WATER) (2007-2010) and the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) (2012-2015). Among these two experiments, an important result of WATER has been the generation of some multi-scale, high-quality comprehensive datasets, which have greatly supported the development, improvement and validation of a series of ecological, hydrological and quantitative remote-sensing models. The goal of a breakthrough for solving the "data bottleneck" problem has been achieved. HiWATER was initiated in 2012. This project has established a world-class hydrological and meteorological observation network, a flux measurement matrix and an eco-hydrological wireless sensor network. A set of super high-resolution airborne remote-sensing data has also been obtained. In addition, there has been important progress with regard to the scaling research. Furthermore, the automatic acquisition, transmission, quality control and remote control of the observational data has been realized through the use of wireless sensor network technology. The observation and information systems have been highly integrated, which will provide a solid foundation for establishing a research platform that integrates observation, data management, model simulation, scenario analysis and decision-making support to foster 21st-century watershed science in China.

  9. Mobile colloid generation induced by a cementitious plume: mineral surface-charge controls on mobilization.

    PubMed

    Li, Dien; Kaplan, Daniel I; Roberts, Kimberly A; Seaman, John C

    2012-03-06

    Cementitious materials are increasingly used as engineered barriers and waste forms for radiological waste disposal. Yet their potential effect on mobile colloid generation is not well-known, especially as it may influence colloid-facilitated contaminant transport. Whereas previous papers have studied the introduction of cement colloids into sediments, this study examined the influence of cement leachate chemistry on the mobilization of colloids from a subsurface sediment collected from the Savannah River Site, USA. A sharp mobile colloid plume formed with the introduction of a cement leachate simulant. Colloid concentrations decreased to background concentrations even though the aqueous chemical conditions (pH and ionic strength) remained unchanged. Mobile colloids were mainly goethite and to a lesser extent kaolinite. The released colloids had negative surface charges and the mean particle sizes ranged primarily from 200 to 470 nm. Inherent mineralogical electrostatic forces appeared to be the controlling colloid removal mechanism in this system. In the background pH of ~6.0, goethite had a positive surface charge, whereas quartz (the dominant mineral in the immobile sediment) and kaolinite had negative surface charges. Goethite acted as a cementing agent, holding kaolinite and itself onto the quartz surfaces due to the electrostatic attraction. Once the pH of the system was elevated, as in the cementitious high pH plume front, the goethite reversed to a negative charge, along with quartz and kaolinite, then goethite and kaolinite colloids were mobilized and a sharp spike in turbidity was observed. Simulating conditions away from the cementitious source, essentially no colloids were mobilized at 1:1000 dilution of the cement leachate or when the leachate pH was ≤ 8. Extreme alkaline pH environments of cementitious leachate may change mineral surface charges, temporarily promoting the formation of mobile colloids.

  10. In situ measurement of the rheological properties and agglomeration on cementitious pastes

    SciTech Connect

    Kim, Jae Hong; Yim, Hong Jae; Ferron, Raissa Douglas

    2016-07-15

    Various factors influence the rheology of cementitious pastes, with the most important being the mixing protocol, mixture proportions, and mixture composition. This study investigated the influence of ground-granulated blast-furnace slag, on the rheological behavior of cementitious pastes. In tandem with the rheological measurements, fresh state microstructural measurements were conducted using three different techniques: A coupled stroboscope-rheometer, a coupled laser backscattering-rheometer, and a conventional laser diffraction technique. Laser diffraction and the coupled stroboscope-rheometer were not good measures of the in situ state of flocculation of a sample. Rather, only the laser backscattering technique allowed for in situ measurement on a highly concentrated suspension (cementitious paste). Using the coupled laser backscattering-rheometer technique, a link between the particle system and rheological behavior was determined through a modeling approach that takes into account agglomeration properties. A higher degree of agglomeration was seen in the ordinary Portland cement paste than pastes containing the slag and this was related to the degree of capillary pressure in the paste systems.

  11. Analysis of Graphite Reinforced Cementitious Composites

    NASA Technical Reports Server (NTRS)

    Vaughan, Robert E.; Gilbert, John A.; Spanyer, Karen (Technical Monitor)

    2001-01-01

    This paper describes analytical methods that can be used to determine the deflections and stresses in highly compliant graphite-reinforced cementitious composites. It is demonstrated that the standard transform section fails to provide accurate results when the elastic modulus ratio exceeds 20. So an alternate approach is formulated by using the rule of mixtures to determine a set of effective material properties for the composite. Tensile tests are conducted on composite samples to verify this approach; and, when the effective material properties are used to characterize the deflections of composite beams subject to pure bending, an excellent agreement is obtained. Laminated composite plate theory is also investigated as a means for analyzing even more complex composites, consisting of multiple graphite layers oriented in different directions. In this case, composite beams are analyzed by incorporating material properties established from tensile tests. Finite element modeling is used to verity the results and, considering the complexity of the samples, a very good agreement is obtained.

  12. Entombment Using Cementitious Materials: Design Considerations and International Experience

    SciTech Connect

    Seitz, Roger Ray

    2002-08-01

    Cementitious materials have physical and chemical properties that are well suited for the requirements of radioactive waste management. Namely, the materials have low permeability and durability that is consistent with the time frame required for short-lived radionuclides to decay. Furthermore, cementitious materials can provide a long-term chemical environment that substantially reduces the mobility of some long-lived radionuclides of concern for decommissioning (e.g., C-14, Ni-63, Ni-59). Because of these properties, cementitious materials are common in low-level radioactive waste disposal facilities throughout the world and are an attractive option for entombment of nuclear facilities. This paper describes design considerations for cementitious barriers in the context of performance over time frames of a few hundreds of years (directed toward short-lived radionuclides) and time frames of thousands of years (directed towards longer-lived radionuclides). The emphasis is on providing an overview of concepts for entombment that take advantage of the properties of cementitious materials and experience from the design of low-level radioactive waste disposal facilities. A few examples of the previous use of cementitious materials for entombment of decommissioned nuclear facilities and proposals for the use in future decommissioning of nuclear reactors in a few countries are also included to provide global perspective.

  13. Entombment Using Cementitious Materials: Design Considerations and International Experience

    SciTech Connect

    Seitz, R.R.

    2002-05-15

    Cementitious materials have physical and chemical properties that are well suited for the requirements of radioactive waste management. Namely, the materials have low permeability and durability that is consistent with the time frame required for short-lived radionuclides to decay. Furthermore, cementitious materials can provide a long-term chemical environment that substantially reduces the mobility of some long-lived radionuclides of concern for decommissioning (e.g., C-14, Ni-63, Ni-59). Because of these properties, cementitious materials are common in low-level radioactive waste disposal facilities throughout the world and are an attractive option for entombment of nuclear facilities. This paper describes design considerations for cementitious barriers in the context of performance over time frames of a few hundreds of years (directed toward short-lived radionuclides) and time frames of thousands of years (directed towards longer-lived radionuclides). The emphasis is on providing a n overview of concepts for entombment that take advantage of the properties of cementitious materials and experience from the design of low-level radioactive waste disposal facilities. A few examples of the previous use of cementitious materials for entombment of decommissioned nuclear facilities and proposals for the use in future decommissioning of nuclear reactors in a few countries are also included to provide global perspective.

  14. Perspective: Differential dynamic microscopy extracts multi-scale activity in complex fluids and biological systems

    NASA Astrophysics Data System (ADS)

    Cerbino, Roberto; Cicuta, Pietro

    2017-09-01

    Differential dynamic microscopy (DDM) is a technique that exploits optical microscopy to obtain local, multi-scale quantitative information about dynamic samples, in most cases without user intervention. It is proving extremely useful in understanding dynamics in liquid suspensions, soft materials, cells, and tissues. In DDM, image sequences are analyzed via a combination of image differences and spatial Fourier transforms to obtain information equivalent to that obtained by means of light scattering techniques. Compared to light scattering, DDM offers obvious advantages, principally (a) simplicity of the setup; (b) possibility of removing static contributions along the optical path; (c) power of simultaneous different microscopy contrast mechanisms; and (d) flexibility of choosing an analysis region, analogous to a scattering volume. For many questions, DDM has also advantages compared to segmentation/tracking approaches and to correlation techniques like particle image velocimetry. The very straightforward DDM approach, originally demonstrated with bright field microscopy of aqueous colloids, has lately been used to probe a variety of other complex fluids and biological systems with many different imaging methods, including dark-field, differential interference contrast, wide-field, light-sheet, and confocal microscopy. The number of adopting groups is rapidly increasing and so are the applications. Here, we briefly recall the working principles of DDM, we highlight its advantages and limitations, we outline recent experimental breakthroughs, and we provide a perspective on future challenges and directions. DDM can become a standard primary tool in every laboratory equipped with a microscope, at the very least as a first bias-free automated evaluation of the dynamics in a system.

  15. Modeling ventricular interaction: a multiscale approach from sarcomere mechanics to cardiovascular system hemodynamics.

    PubMed

    Lumens, Joost; Delhaas, Tammo; Kirn, Borut; Arts, Theo

    2008-01-01

    Direct ventricular interaction via the interventricular septum plays an important role in ventricular hemodynamics and mechanics. A large amount of experimental data demonstrates that left and right ventricular pump mechanics influence each other and that septal geometry and motion depend on transmural pressure. We present a lumped model of ventricular mechanics consisting of three wall segments that are coupled on the basis of balance laws stating mechanical equilibrium at the intersection of the three walls. The input consists of left and right ventricular volumes and an estimate of septal wall geometry. Wall segment geometry is expressed as area and curvature and is related to sarcomere extension. With constitutive equations of the sarcomere, myofiber stress is calculated. The force exerted by each wall segment on the intersection, as a result of wall tension, is derived from myofiber stress. Finally, septal geometry and ventricular pressures are solved by achieving balance of forces. We implemented this ventricular module in a lumped model of the closed-loop cardiovascular system (CircAdapt model) The resulting multiscale model enables dynamic simulation of myofiber mechanics, ventricular cavity mechanics, and cardiovascular system hemodynamics. The model was tested by performing simulations with synchronous and asynchronous mechanical activation of the wall segments. The simulated results of ventricular mechanics and hemodynamics were compared with experimental data obtained before and after acute induction of left bundle branch block (LBBB) in dogs. The changes in simulated ventricular mechanics and septal motion as a result of the introduction of mechanical asynchrony were very similar to those measured in the animal experiments. In conclusion, the module presented describes ventricular mechanics including direct ventricular interaction realistically and thereby extends the physiological application range of the CircAdapt model.

  16. Perspective: Differential dynamic microscopy extracts multi-scale activity in complex fluids and biological systems.

    PubMed

    Cerbino, Roberto; Cicuta, Pietro

    2017-09-21

    Differential dynamic microscopy (DDM) is a technique that exploits optical microscopy to obtain local, multi-scale quantitative information about dynamic samples, in most cases without user intervention. It is proving extremely useful in understanding dynamics in liquid suspensions, soft materials, cells, and tissues. In DDM, image sequences are analyzed via a combination of image differences and spatial Fourier transforms to obtain information equivalent to that obtained by means of light scattering techniques. Compared to light scattering, DDM offers obvious advantages, principally (a) simplicity of the setup; (b) possibility of removing static contributions along the optical path; (c) power of simultaneous different microscopy contrast mechanisms; and (d) flexibility of choosing an analysis region, analogous to a scattering volume. For many questions, DDM has also advantages compared to segmentation/tracking approaches and to correlation techniques like particle image velocimetry. The very straightforward DDM approach, originally demonstrated with bright field microscopy of aqueous colloids, has lately been used to probe a variety of other complex fluids and biological systems with many different imaging methods, including dark-field, differential interference contrast, wide-field, light-sheet, and confocal microscopy. The number of adopting groups is rapidly increasing and so are the applications. Here, we briefly recall the working principles of DDM, we highlight its advantages and limitations, we outline recent experimental breakthroughs, and we provide a perspective on future challenges and directions. DDM can become a standard primary tool in every laboratory equipped with a microscope, at the very least as a first bias-free automated evaluation of the dynamics in a system.

  17. A Multi-Scale Energy Food Systems Modeling Framework For Climate Adaptation

    NASA Astrophysics Data System (ADS)

    Siddiqui, S.; Bakker, C.; Zaitchik, B. F.; Hobbs, B. F.; Broaddus, E.; Neff, R.; Haskett, J.; Parker, C.

    2016-12-01

    Our goal is to understand coupled system dynamics across scales in a manner that allows us to quantify the sensitivity of critical human outcomes (nutritional satisfaction, household economic well-being) to development strategies and to climate or market induced shocks in sub-Saharan Africa. We adopt both bottom-up and top-down multi-scale modeling approaches focusing our efforts on food, energy, water (FEW) dynamics to define, parameterize, and evaluate modeled processes nationally as well as across climate zones and communities. Our framework comprises three complementary modeling techniques spanning local, sub-national and national scales to capture interdependencies between sectors, across time scales, and on multiple levels of geographic aggregation. At the center is a multi-player micro-economic (MME) partial equilibrium model for the production, consumption, storage, and transportation of food, energy, and fuels, which is the focus of this presentation. We show why such models can be very useful for linking and integrating across time and spatial scales, as well as a wide variety of models including an agent-based model applied to rural villages and larger population centers, an optimization-based electricity infrastructure model at a regional scale, and a computable general equilibrium model, which is applied to understand FEW resources and economic patterns at national scale. The MME is based on aggregating individual optimization problems for relevant players in an energy, electricity, or food market and captures important food supply chain components of trade and food distribution accounting for infrastructure and geography. Second, our model considers food access and utilization by modeling food waste and disaggregating consumption by income and age. Third, the model is set up to evaluate the effects of seasonality and system shocks on supply, demand, infrastructure, and transportation in both energy and food.

  18. Reduction of communication requirements for wide-area surveillance systems: multiscale clipping service

    NASA Astrophysics Data System (ADS)

    Chaney, Ronald D.; Van Allen, Eric J.; Dudgeon, Dan E.

    1996-06-01

    system utilizes a multiple-resolution image formation algorithm to reduce computational load: ATD/R algorithms are applied to coarse resolution imagery; the imagery is subsequently processed to fine resolution imagery only where targets are likely to be present. This reduces computation because only a fraction of the imagery is processed to fine resolution. In the paper, we determine the communication requirements for the multiscale system assuming Tier II+ parameters. We demonstrate that it is feasible to transmit Tier II+ imagery via a T1 data link using the clipping service concept.

  19. Multi-scale dynamical behavior of spatially distributed systems: a deterministic point of view

    NASA Astrophysics Data System (ADS)

    Mangiarotti, S.; Le Jean, F.; Drapeau, L.; Huc, M.

    2015-12-01

    Physical and biophysical systems are spatially distributed systems. Their behavior can be observed or modelled spatially at various resolutions. In this work, a deterministic point of view is adopted to analyze multi-scale behavior taking a set of ordinary differential equation (ODE) as elementary part of the system.To perform analyses, scenes of study are thus generated based on ensembles of identical elementary ODE systems. Without any loss of generality, their dynamics is chosen chaotic in order to ensure sensitivity to initial conditions, that is, one fundamental property of atmosphere under instable conditions [1]. The Rössler system [2] is used for this purpose for both its topological and algebraic simplicity [3,4].Two cases are thus considered: the chaotic oscillators composing the scene of study are taken either independent, or in phase synchronization. Scale behaviors are analyzed considering the scene of study as aggregations (basically obtained by spatially averaging the signal) or as associations (obtained by concatenating the time series). The global modeling technique is used to perform the numerical analyses [5].One important result of this work is that, under phase synchronization, a scene of aggregated dynamics can be approximated by the elementary system composing the scene, but modifying its parameterization [6]. This is shown based on numerical analyses. It is then demonstrated analytically and generalized to a larger class of ODE systems. Preliminary applications to cereal crops observed from satellite are also presented.[1] Lorenz, Deterministic nonperiodic flow. J. Atmos. Sci., 20, 130-141 (1963).[2] Rössler, An equation for continuous chaos, Phys. Lett. A, 57, 397-398 (1976).[3] Gouesbet & Letellier, Global vector-field reconstruction by using a multivariate polynomial L2 approximation on nets, Phys. Rev. E 49, 4955-4972 (1994).[4] Letellier, Roulin & Rössler, Inequivalent topologies of chaos in simple equations, Chaos, Solitons

  20. Competition behaviour of metal uptake in cementitious systems: An XRD and EXAFS investigation of Nd- and Zn-loaded 11 Å tobermorite

    NASA Astrophysics Data System (ADS)

    Vespa, M.; Dähn, R.; Wieland, E.

    Cement-based materials play an important role in multi-barrier concepts developed worldwide for the safe disposal of hazardous and radioactive wastes. Cement is used to condition and stabilize the waste materials and to construct the engineered barrier systems (container, backfill and liner materials) of repositories for radioactive waste. In this study, bulk-X-ray absorption spectroscopy (XAS) was used to investigate the uptake mechanism of Nd on the crystalline C-S-H phase 11 Å tobermorite in the presence of Zn (co-absorbing metal), and vice versa, as potential competitor under strongly alkaline conditions (pH = 12.5-13.3). The Zn and Nd concentration in all samples was 50,000 ppm, whereas the reaction times varied from 1 to 6 months. Extended X-ray absorption fine structure (EXAFS) data of the Nd LIII-edge indicate that the local structural environment of Nd consists of ∼7-8 O atoms at 2.42 Å, ∼7-8 Si at ∼3.67 Å and ∼5-6 Ca at ∼3.8 Å, and that this environment remains unchanged in the presence and absence of Zn. In contrary, Zn K-edge EXAFS data exhibit distinct differences in the presence and absence of Nd as co-absorbing element. Data analysis indicates that Zn is tetrahedrally coordinated (∼4 O at ∼1.96 Å) and the obtained structural data in the simultaneous presence of Nd and Zn are consistent with the formation of mixed Zn surface complexes and Zn bound in the interlayer remaining in these positions also with prolonged reaction times (up to 6 months). However, without the co-absorbing element Nd, strong structural changes in the uptake mechanisms of Zn are observable, e.g., after 3 month reaction time Zn-Zn backscattering pairs can be observed. These findings suggest that Nd has an influence on the incorporation of Zn in the tobermorite structure. In addition, the results of this study indicate that competitive uptake of metal cations with similar sorption behaviour by C-S-H phases can take place, deserving further attention in future

  1. A novel two-dimensional method to measure surface shrinkage in cementitious materials

    SciTech Connect

    Chen, T.C.; Ferraro, C.C.; Yin, W.Q.; Ishee, C.A.; Ifju, P.G.

    2010-05-15

    A novel experimental technique, Cure Reference Method (CRM), was developed for the measurement of surface shrinkage in cementitious materials. The technique combines the replication of diffraction grating on a specimen during the curing process and the use of high-sensitivity moire interferometry. Once demolded, the specimen was stored in an environmental chamber in order to establish specific curing conditions. Measurements were conducted on a daily basis for the duration of 7 days by recording a set of the consecutive phase shifted fringe patterns using the Portable Engineering Moire interferometer II (PEMI II). An automated fringe analysis system was developed and used to obtain displacement and strain information in two dimenzsions. Surface shrinkage behavior in both cement paste and mortar specimens was investigated by the use of the technique under controlled temperature and humidity conditions. Furthermore, an experimental control was developed in an effort to remove the effects of drying shrinkage on cementitious specimens at early ages. This was done in an effort to explore the relative contribution of autogenous shrinkage to the overall shrinkage in cementitious materials.

  2. Hydration characteristics and environmental friendly performance of a cementitious material composed of calcium silicate slag.

    PubMed

    Zhang, Na; Li, Hongxu; Zhao, Yazhao; Liu, Xiaoming

    2016-04-05

    Calcium silicate slag is an alkali leaching waste generated during the process of extracting Al2O3 from high-alumina fly ash. In this research, a cementitious material composed of calcium silicate slag was developed, and its mechanical and physical properties, hydration characteristics and environmental friendly performance were investigated. The results show that an optimal design for the cementitious material composed of calcium silicate slag was determined by the specimen CFSC7 containing 30% calcium silicate slag, 5% high-alumina fly ash, 24% blast furnace slag, 35% clinker and 6% FGD gypsum. This blended system yields excellent physical and mechanical properties, confirming the usefulness of CFSC7. The hydration products of CFSC7 are mostly amorphous C-A-S-H gel, rod-like ettringite and hexagonal-sheet Ca(OH)2 with small amount of zeolite-like minerals such as CaAl2Si2O8·4H2O and Na2Al2Si2O8·H2O. As the predominant hydration products, rod-like ettringite and amorphous C-A-S-H gel play a positive role in promoting densification of the paste structure, resulting in strength development of CFSC7 in the early hydration process. The leaching toxicity and radioactivity tests results indicate that the developed cementitious material composed of calcium silicate slag is environmentally acceptable. This study points out a promising direction for the proper utilization of calcium silicate slag in large quantities.

  3. Recent Enhancements to the Community Multiscale Air Quality Modeling System (CMAQ)

    EPA Science Inventory

    EPA’s Office of Research and Development, Computational Exposure Division held a webinar on January 31, 2017 to present the recent scientific and computational updates made by EPA to the Community Multi-Scale Air Quality Model (CMAQ). Topics covered included: (1) Improveme...

  4. Overview and Evaluation of the Community Multiscale Air Quality (CMAQ) Modeling System Version 5.2

    EPA Science Inventory

    A new version of the Community Multiscale Air Quality (CMAQ) model, version 5.2 (CMAQv5.2), is currently being developed, with a planned release date in 2017. The new model includes numerous updates from the previous version of the model (CMAQv5.1). Specific updates include a new...

  5. Recent Enhancements to the Community Multiscale Air Quality Modeling System (CMAQ)

    EPA Science Inventory

    EPA’s Office of Research and Development, Computational Exposure Division held a webinar on January 31, 2017 to present the recent scientific and computational updates made by EPA to the Community Multi-Scale Air Quality Model (CMAQ). Topics covered included: (1) Improveme...

  6. The impact of simulated mesoscale convective systems on global precipitation: A multiscale modeling study

    NASA Astrophysics Data System (ADS)

    Tao, Wei-Kuo; Chern, Jiun-Dar

    2017-06-01

    The importance of precipitating mesoscale convective systems (MCSs) has been quantified from TRMM precipitation radar and microwave imager retrievals. MCSs generate more than 50% of the rainfall in most tropical regions. MCSs usually have horizontal scales of a few hundred kilometers (km); therefore, a large domain with several hundred km is required for realistic simulations of MCSs in cloud-resolving models (CRMs). Almost all traditional global and climate models do not have adequate parameterizations to represent MCSs. Typical multiscale modeling frameworks (MMFs) may also lack the resolution (4 km grid spacing) and domain size (128 km) to realistically simulate MCSs. The impact of MCSs on precipitation is examined by conducting model simulations using the Goddard Cumulus Ensemble (GCE, a CRM) model and Goddard MMF that uses the GCEs as its embedded CRMs. Both models can realistically simulate MCSs with more grid points (i.e., 128 and 256) and higher resolutions (1 or 2 km) compared to those simulations with fewer grid points (i.e., 32 and 64) and low resolution (4 km). The modeling results also show the strengths of the Hadley circulations, mean zonal and regional vertical velocities, surface evaporation, and amount of surface rainfall are weaker or reduced in the Goddard MMF when using more CRM grid points and higher CRM resolution. In addition, the results indicate that large-scale surface evaporation and wind feedback are key processes for determining the surface rainfall amount in the GMMF. A sensitivity test with reduced sea surface temperatures shows both reduced surface rainfall and evaporation.

  7. Patient-specific modeling and multi-scale blood simulation for computational hemodynamic study on the human cerebrovascular system.

    PubMed

    Oshima, Marie; Torii, Ryo; Tokuda, Shigefumi; Yamada, Shigeki; Koizumi, Akio

    2012-09-01

    To develop a targeted drug delivery system for cerebrovascular disorders such as stroke, it is important to obtain detailed information on flow rates and hemodynamics of the human cerebrovascular system for individual patients. A patient-specific integrated numerical simulation system has been developed by the authors such that vascular geometry is constructed from medical images such as magnetic resonance imaging (MRI) or computed tomography (CT) data, and computational conditions are modeled mathematically to represent the realistic in vivo environments. In general, the three-dimensional numerical simulation using a patient-specific model is conducted only for a localized diseased region with atherosclerosis or an aneurysm. Although the analysis region is only a part of the circulatory system, the simulation should include the effects from the entire circulatory system. Since the peripheral network determines the flow distributions in the cerebrovascular system, the paper reviews the recent simulation methods to take into account the network by coupling the image-based three-dimensional simulation with a one- and zero-dimensional simulations as an outflow boundary condition The paper shows the mathematical modeling of the multi-scale outflow boundary condition and its applications to patient- specific models of the arterial circle of Willis. The results are compared to those using the conventional, free-stream boundary condition. As a result, the multi-scale outflow boundary condition shows a significant difference in flow rate of each artery and in flow distribution in the arterial circle of Willis.

  8. Multi-scale Properties and Processes in Hierarchically-Structured Organic-Inorganic Solids and Surface-Based Microfluidic Systems

    NASA Astrophysics Data System (ADS)

    Messinger, Robert James

    Hierarchically-structured materials and surface-based microfluidic systems exhibit diverse properties that are inherently multi-scale in origin. In particular, different molecular, mesoscopic, and micron-scale properties and processes are often correlated and collectively account for many properties of interest, such as bulk catalytic activities or electrokinetic flow rates. However, such properties and processes often exhibit complex relationships over the different length scales that are not well understood, and consequently, difficult to control. Establishing correlations between them has been challenging, in part due to the difficulty of rigorously characterizing complex, heterogeneous materials and surface-based microfluidic experiments over multiple length scales, particularly at the molecular and mesoscopic levels. Herein, new multi-scale understanding and correlations have been established for different hierarchically-structured organic-inorganic solids or surface-based microfluidic systems, enabling control of material or device properties over discrete length scales. The molecular-level compositions, structures, interactions, and dynamics have been measured in diverse hierarchically-structured materials, such as mesostructured zeolites, mesostructured organosilicas, and organosiloxane foams, and subsequently correlated with their meso- and macroscopic material structures and properties. The results reveal new insights on the molecular-level interactions that govern their syntheses, the resulting local compositions and material structures, and the relationships among material properties over multiple characteristic length scales. Multi-dimensional solid-state nuclear magnetic resonance (NMR) spectroscopy is a cornerstone of these investigations, which enables correlative measurements in multiple frequency dimensions of the through-space or through-bond interactions between the constituent nuclei within the different materials. Other multi-scale

  9. Multiscale Characterization

    DTIC Science & Technology

    2009-09-04

    reinforcement / matrix interface bonded interfaces microvascular channels composite...Composites Characterization Scales reinforcement / matrix interface bonded interfaces microvascular channels composite layer properties structural response cm nm µm mm ...AFOSR-MURI Functionally Graded Hybrid Composites Multiscale Characterization Characterization of Composite Layers •  Graded Ceramic/Metal Matrix

  10. Attitude Ground System (AGS) For The Magnetospheric Multi-Scale (MMS) Mission

    NASA Technical Reports Server (NTRS)

    Raymond, Juan C.; Sedlak, Joseph E.; Vint, Babak

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission is a Solar-Terrestrial Probe mission consisting of four identically instrumented spin-stabilized spacecraft flying in an adjustable pyramid-like formation around the Earth. The formation of the MMS spacecraft allows for three-dimensional study of the phenomenon of magnetic reconnection, which is the primary objective of the mission. The MMS spacecraft were launched early on March 13, 2015 GMT. Due to the challenging and very constricted attitude and orbit requirements for performing the science, as well as the need to maintain the spacecraft formation, multiple ground functionalities were designed to support the mission. These functionalities were incorporated into a ground system known as the Attitude Ground System (AGS). Various AGS configurations have been used widely to support a variety of three-axis-stabilized and spin-stabilized spacecraft missions within the NASA Goddard Space Flight Center (GSFC). The original MMS operational concept required the AGS to perform highly accurate predictions of the effects of environmental disturbances on the spacecraft orientation and to plan the attitude maneuvers necessary to stay within the science attitude tolerance. The orbit adjustment requirements for formation control drove the need also to perform calibrations that have never been done before in support of NASA GSFC missions. The MMS mission required support analysts to provide fast and accurately calibrated values of the inertia tensor, center of mass, and accelerometer bias for each MMS spacecraft. During early design of the AGS functionalities, a Kalman filter for estimating the attitude, body rates, center of mass, and accelerometer bias, using only star tracker and accelerometer measurements, was heavily analyzed. A set of six distinct filters was evaluated and considered for estimating the spacecraft attitude and body rates using star tracker data only. Four of the six filters are closely related and were compared

  11. Cementitious Barriers Partnership (CBP): Training and Release of CBP Toolbox Software, Version 1.0 - 13480

    SciTech Connect

    Brown, K.G.; Kosson, D.S.; Garrabrants, A.C.; Sarkar, S.; Flach, G.; Langton, C.; Smith, F.G. III; Burns, H.; Van der Sloot, H.; Meeussen, J.C.L.; Samson, E.; Mallick, P.; Suttora, L.; Esh, D.; Fuhrmann, M.; Philip, J.

    2013-07-01

    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the Office of Tank Waste Management within the Office of Environmental Management of U.S. Department of Energy (US DOE). The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that improve understanding and predictions of the long-term hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program are intended to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to or longer than 100 years for operating facilities and longer than 1,000 years for waste management purposes. CBP software tools were made available to selected DOE Office of Environmental Management and field site users for training and evaluation based on a set of important degradation scenarios, including sulfate ingress/attack and carbonation of cementitious materials. The tools were presented at two-day training workshops held at U.S. National Institute of Standards and Technology (NIST), Savannah River, and Hanford included LeachXS{sup TM}/ORCHESTRA, STADIUM{sup R}, and a CBP-developed GoldSim Dashboard interface. Collectively, these components form the CBP Software Toolbox. The new U.S. Environmental Protection Agency leaching test methods based on the Leaching Environmental Assessment Framework (LEAF) were also presented. The CBP Dashboard uses a custom Dynamic-link library developed by CBP to couple to the LeachXS{sup TM}/ORCHESTRA and STADIUM{sup R} codes to simulate reactive transport and degradation in cementitious materials for selected performance assessment scenarios. The first day of the workshop introduced participants to the software components via presentation materials, and the second day included hands-on tutorial exercises followed

  12. Systems-Pharmacology Dissection of Traditional Chinese Medicine Compound Saffron Formula Reveals Multi-scale Treatment Strategy for Cardiovascular Diseases

    PubMed Central

    Liu, Jianling; Mu, Jiexin; Zheng, Chunli; Chen, Xuetong; Guo, Zihu; Huang, Chao; Fu, Yingxue; Tian, Guihua; Shang, Hongcai; Wang, Yonghua

    2016-01-01

    Cardiovascular diseases (CVDs) have been regarding as “the world’s first killer” of human beings in recent years owing to the striking morbidity and mortality, the involved molecular mechanisms are extremely complex and remain unclear. Traditional Chinese medicine (TCM) adheres to the aim of combating complex diseases from an integrative and holistic point of view, which has shown effectiveness in CVDs therapy. However, system-level understanding of such a mechanism of multi-scale treatment strategy for CVDs is still difficult. Here, we developed a system pharmacology approach with the purpose of revealing the underlying molecular mechanisms exemplified by a famous compound saffron formula (CSF) in treating CVDs. First, by systems ADME analysis combined with drug targeting process, 103 potential active components and their corresponding 219 direct targets were retrieved and some key interactions were further experimentally validated. Based on this, the network relationships among active components, targets and diseases were further built to uncover the pharmacological actions of the drug. Finally, a “CVDs pathway” consisted of several regulatory modules was incorporated to dissect the therapeutic effects of CSF in different pathological features-relevant biological processes. All this demonstrates CSF has multi-scale curative activity in regulating CVD-related biological processes, which provides a new potential way for modern medicine in the treatment of complex diseases. PMID:26813334

  13. A multi-scale modeling framework for instabilities of film/substrate systems

    NASA Astrophysics Data System (ADS)

    Xu, Fan; Potier-Ferry, Michel

    2016-01-01

    Spatial pattern formation in stiff thin films on soft substrates is investigated from a multi-scale point of view based on a technique of slowly varying Fourier coefficients. A general macroscopic modeling framework is developed and then a simplified macroscopic model is derived. The model incorporates Asymptotic Numerical Method (ANM) as a robust path-following technique to trace the post-buckling evolution path and to predict secondary bifurcations. The proposed multi-scale finite element framework allows sinusoidal and square checkerboard patterns as well as their bifurcation portraits to be described from a quantitative standpoint. Moreover, it provides an efficient way to compute large-scale instability problems with a significant reduction of computational cost compared to full models.

  14. Multiscale systems analysis of root growth and development: modeling beyond the network and cellular scales.

    PubMed

    Band, Leah R; Fozard, John A; Godin, Christophe; Jensen, Oliver E; Pridmore, Tony; Bennett, Malcolm J; King, John R

    2012-10-01

    Over recent decades, we have gained detailed knowledge of many processes involved in root growth and development. However, with this knowledge come increasing complexity and an increasing need for mechanistic modeling to understand how those individual processes interact. One major challenge is in relating genotypes to phenotypes, requiring us to move beyond the network and cellular scales, to use multiscale modeling to predict emergent dynamics at the tissue and organ levels. In this review, we highlight recent developments in multiscale modeling, illustrating how these are generating new mechanistic insights into the regulation of root growth and development. We consider how these models are motivating new biological data analysis and explore directions for future research. This modeling progress will be crucial as we move from a qualitative to an increasingly quantitative understanding of root biology, generating predictive tools that accelerate the development of improved crop varieties.

  15. Multiscale Systems Analysis of Root Growth and Development: Modeling Beyond the Network and Cellular Scales

    PubMed Central

    Band, Leah R.; Fozard, John A.; Godin, Christophe; Jensen, Oliver E.; Pridmore, Tony; Bennett, Malcolm J.; King, John R.

    2012-01-01

    Over recent decades, we have gained detailed knowledge of many processes involved in root growth and development. However, with this knowledge come increasing complexity and an increasing need for mechanistic modeling to understand how those individual processes interact. One major challenge is in relating genotypes to phenotypes, requiring us to move beyond the network and cellular scales, to use multiscale modeling to predict emergent dynamics at the tissue and organ levels. In this review, we highlight recent developments in multiscale modeling, illustrating how these are generating new mechanistic insights into the regulation of root growth and development. We consider how these models are motivating new biological data analysis and explore directions for future research. This modeling progress will be crucial as we move from a qualitative to an increasingly quantitative understanding of root biology, generating predictive tools that accelerate the development of improved crop varieties. PMID:23110897

  16. Micro- and macroscale coefficients of friction of cementitious materials

    SciTech Connect

    Lomboy, Gilson; Sundararajan, Sriram; Wang, Kejin

    2013-12-15

    Millions of metric tons of cementitious materials are produced, transported and used in construction each year. The ease or difficulty of handling cementitious materials is greatly influenced by the material friction properties. In the present study, the coefficients of friction of cementitious materials were measured at the microscale and macroscale. The materials tested were commercially-available Portland cement, Class C fly ash, and ground granulated blast furnace slag. At the microscale, the coefficient of friction was determined from the interaction forces between cementitious particles using an Atomic Force Microscope. At the macroscale, the coefficient of friction was determined from stresses on bulk cementitious materials under direct shear. The study indicated that the microscale coefficient of friction ranged from 0.020 to 0.059, and the macroscale coefficient of friction ranged from 0.56 to 0.75. The fly ash studied had the highest microscale coefficient of friction and the lowest macroscale coefficient of friction. -- Highlights: •Microscale (interparticle) coefficient of friction (COF) was determined with AFM. •Macroscale (bulk) COF was measured under direct shear. •Fly ash had the highest microscale COF and the lowest macroscale COF. •Portland cement against GGBFS had the lowest microscale COF. •Portland cement against Portland cement had the highest macroscale COF.

  17. REVIEW OF THE GOVERNING EQUATIONS, COMPUTATIONAL ALGORITHMS, AND OTHER COMPONENTS OF THE MODELS-3 COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODELING SYSTEM

    EPA Science Inventory

    This article describes the governing equations, computational algorithms, and other components entering into the Community Multiscale Air Quality (CMAQ) modeling system. This system has been designed to approach air quality as a whole by including state-of-the-science capabiliti...

  18. REVIEW OF THE GOVERNING EQUATIONS, COMPUTATIONAL ALGORITHMS, AND OTHER COMPONENTS OF THE MODELS-3 COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODELING SYSTEM

    EPA Science Inventory

    This article describes the governing equations, computational algorithms, and other components entering into the Community Multiscale Air Quality (CMAQ) modeling system. This system has been designed to approach air quality as a whole by including state-of-the-science capabiliti...

  19. Concrete mixture characterization. Cementitious barriers partnership

    SciTech Connect

    Langton, C.; Protiere, Yannick

    2014-12-01

    This report summarizes the characterization study performed on two concrete mixtures used for radioactive waste storage. Both mixtures were prepared with approximately 425 kg of binder. The testing protocol mostly focused on determining the transport properties of the mixtures; volume of permeable voids (porosity), diffusion coefficients, and water permeability were evaluated. Tests were performed after different curing durations. In order to obtain data on the statistical distribution of transport properties, the measurements after 2 years of curing were performed on 10+ samples. Overall, both mixtures exhibited very low tortuosities and permeabilities, a direct consequence of their low water-to-binder ratio and the use of supplementary cementitious materials. The data generated on 2-year old samples showed that porosity, tortuosity and permeability follow a normal distribution. Chloride ponding tests were also performed on test samples. They showed limited chloride ingress, in line with measured transport properties. These test results also showed that both materials react differently with chloride, a consequence of the differences in the binder chemical compositions.

  20. Cementitious waste option scoping study report

    SciTech Connect

    Lee, A.E.; Taylor, D.D.

    1998-02-01

    A Settlement Agreement between the Department of Energy (DOE) and the State of Idaho mandates that all high-level radioactive waste (HLW) now stored at the Idaho Chemical Processing Plant (ICPP) on the Idaho National Engineering and Environmental Laboratory (INEEL) will be treated so that it is ready to be moved out of Idaho for disposal by a target date of 2035. This study investigates the nonseparations Cementitious Waste Option (CWO) as a means to achieve this goal. Under this option all liquid sodium-bearing waste (SBW) and existing HLW calcine would be recalcined with sucrose, grouted, canisterized, and interim stored as a mixed-HLW for eventual preparation and shipment off-Site for disposal. The CWO waste would be transported to a Greater Confinement Disposal Facility (GCDF) located in the southwestern desert of the US on the Nevada Test Site (NTS). All transport preparation, shipment, and disposal facility activities are beyond the scope of this study. CWO waste processing, packaging, and interim storage would occur over a 5-year period between 2013 and 2017. Waste transport and disposal would occur during the same time period.

  1. Multiscale Fluctuation Analysis Revisited

    NASA Astrophysics Data System (ADS)

    Struzik, Zbigniew R.; Kiyono, Ken; Yamamoto, Yoshiharu

    2007-07-01

    Ubiquitous non-Gaussianity of the probability density of (time-series) fluctuations in many real world phenomena has been known and modelled extensively in recent years. Similarly, the analysis of (multi)scaling properties of (fluctuations in) complex systems has become a standard way of addressing unknown complexity. Yet the combined analysis and modelling of multiscale behaviour of probability density — multiscale PDF analysis — has only recently been proposed for the analysis of time series arising in complex systems, such as the cardiac neuro-regulatory system, financial markets or hydrodynamic turbulence. This relatively new technique has helped significantly to expand the previously obtained insights into the phenomena addressed. In particular, it has helped to identify a novel class of scale invariant behaviour of the multiscale PDF in healthy heart rate regulation during daily activity and in a market system undergoing crash dynamics. This kind of invariance reflects invariance of the system under renormalisation and resembles behaviour at criticality of a system undergoing continuous phase transition — indeed in both phenomena, such phase transition behaviour has been revealed. While the precise mechanism underlying invariance of the PDF under system renormalisation of both systems discussed is not to date understood, there is an intimate link between the non-Gaussian PDF characteristics and the persistent invariant correlation structure emerging between fluctuations across scale and time.

  2. Bioaccessibility of nutrients and micronutrients from dispersed food systems: impact of the multiscale bulk and interfacial structures.

    PubMed

    Marze, Sébastien

    2013-01-01

    Many food systems are dispersed systems, that is, they possess at least two immiscible phases. This is generally due to the coexistence of domains with different physicochemical properties separated by many interfaces which control the apparent thermodynamic equilibrium. This feature was and is still largely studied to design pharmaceutical delivery systems. In food science, the recent intensification of in vitro digestion tests to complement the in vivo ones holds promises in the identification of the key parameters controlling the bioaccessibility of nutrients and micronutrients. In this review, we present the developments of in vitro digestion tests for dispersed food systems (mainly emulsions, dispersions and gels). We especially highlight the evidences detailing the roles of the constituting multiscale structures. In a perspective section, we show the potential of structured interfaces to allow controlled bioaccessibility.

  3. Bioreceptivity evaluation of cementitious materials designed to stimulate biological growth.

    PubMed

    Manso, Sandra; De Muynck, Willem; Segura, Ignacio; Aguado, Antonio; Steppe, Kathy; Boon, Nico; De Belie, Nele

    2014-05-15

    Ordinary Portland cement (OPC), the most used binder in construction, presents some disadvantages in terms of pollution (CO2 emissions) and visual impact. For this reason, green roofs and façades have gain considerable attention in the last decade as a way to integrate nature in cities. These systems, however, suffer from high initial and maintenance costs. An alternative strategy to obtain green facades is the direct natural colonisation of the cementitious construction materials constituting the wall, a phenomenon governed by the bioreceptivity of such material. This work aims at assessing the suitability of magnesium phosphate cement (MPC) materials to allow a rapid natural colonisation taking carbonated OPC samples as a reference material. For that, the aggregate size, the w/c ratio and the amount of cement paste of mortars made of both binders were modified. The assessment of the different bioreceptivities was conducted by means of an accelerated algal fouling test. MPC samples exhibited a faster fouling compared to OPC samples, which could be mainly attributed to the lower pH of the MPC binder. In addition to the binder, the fouling rate was governed by the roughness and the porosity of the material. MPC mortar with moderate porosity and roughness appears to be the most feasible material to be used for the development of green concrete walls. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Penetration into Granular Earth Materials (Topic H): A Multi-scale Physics-Based Approach Towards Developing a Greater Understanding of Dynamically Loaded Heterogeneous Systems

    DTIC Science & Technology

    2016-08-01

    Multi-scale Physics -Based Approach Towards Developing a Greater Understanding of Dynamically Loaded Heterogeneous Systems Distribution Statement A...MATERIALS (TOPIC H): HDTRA 1-09-1-0045 A MULTI-SCALE PHYSICS -BASED APPROACH TOWARDS DEVELOPING A GREATER UNDERSTANDING OF DYNAMICALLY Sb. GRANT NUMBER...4.535 924 × 10 –1 kilogram (kg) unified atomic mass unit (amu) 1.660 539 × 10 –27 kilogram (kg) pound-mass per cubic foot (lb ft –3 ) 1.601 846

  5. Land system change and food security: towards multi-scale land system solutions☆

    PubMed Central

    Verburg, Peter H; Mertz, Ole; Erb, Karl-Heinz; Haberl, Helmut; Wu, Wenbin

    2013-01-01

    Land system changes are central to the food security challenge. Land system science can contribute to sustainable solutions by an integrated analysis of land availability and the assessment of the tradeoffs associated with agricultural expansion and land use intensification. A land system perspective requires local studies of production systems to be contextualised in a regional and global context, while global assessments should be confronted with local realities. Understanding of land governance structures will help to support the development of land use policies and tenure systems that assist in designing more sustainable ways of intensification. Novel land systems should be designed that are adapted to the local context and framed within the global socio-ecological system. Such land systems should explicitly account for the role of land governance as a primary driver of land system change and food production. PMID:24143158

  6. A Multimode Optical Imaging System for Preclinical Applications In Vivo: Technology Development, Multiscale Imaging, and Chemotherapy Assessment

    PubMed Central

    Hwang, Jae Youn; Wachsmann-Hogiu, Sebastian; Ramanujan, V. Krishnan; Ljubimova, Julia; Gross, Zeev; Gray, Harry B.; Medina-Kauwe, Lali K.; Farkas, Daniel L.

    2012-01-01

    Purpose Several established optical imaging approaches have been applied, usually in isolation, to preclinical studies; however, truly useful in vivo imaging may require a simultaneous combination of imaging modalities to examine dynamic characteristics of cells and tissues. We developed a new multimode optical imaging system designed to be application-versatile, yielding high sensitivity, and specificity molecular imaging. Procedures We integrated several optical imaging technologies, including fluorescence intensity, spectral, lifetime, intravital confocal, two-photon excitation, and bioluminescence, into a single system that enables functional multiscale imaging in animal models. Results The approach offers a comprehensive imaging platform for kinetic, quantitative, and environmental analysis of highly relevant information, with micro-to-macroscopic resolution. Applied to small animals in vivo, this provides superior monitoring of processes of interest, represented here by chemo-/nanoconstruct therapy assessment. Conclusions This new system is versatile and can be optimized for various applications, of which cancer detection and targeted treatment are emphasized here. PMID:21874388

  7. Thermal conductivity and other properties of cementitious grouts

    SciTech Connect

    Allan, M.

    1998-08-01

    The thermal conductivity and other properties cementitious grouts have been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. In addition to thermal conductivity, the cementitious grouts were also tested for bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the results for selected grout mixes. Relatively high thermal conductivities were obtained and this leads to reduction in predicted bore length and installation costs. Improvements in shrinkage resistance and bonding were achieved.

  8. THERMAL CONDUCTIVITY AND OTHER PROPERTIES OF CEMENTITIOUS GROUTS

    SciTech Connect

    ALLAN,M.

    1998-05-01

    The thermal conductivity and other properties cementitious grouts have been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. In addition to thermal conductivity, the cementitious grouts were also tested for bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the results for selected grout mixes. Relatively high thermal conductivities were obtained and this leads to reduction in predicted bore length and installation costs. Improvements in shrinkage resistance and bonding were achieved.

  9. Multiscale stochastic simulation algorithm with stochastic partial equilibrium assumption for chemically reacting systems

    SciTech Connect

    Cao Yang . E-mail: ycao@cs.ucsb.edu; Gillespie, Dan . E-mail: GillespieDT@mailaps.org; Petzold, Linda . E-mail: petzold@engineering.ucsb.edu

    2005-07-01

    In this paper, we introduce a multiscale stochastic simulation algorithm (MSSA) which makes use of Gillespie's stochastic simulation algorithm (SSA) together with a new stochastic formulation of the partial equilibrium assumption (PEA). This method is much more efficient than SSA alone. It works even with a very small population of fast species. Implementation details are discussed, and an application to the modeling of the heat shock response of E. Coli is presented which demonstrates the excellent efficiency and accuracy obtained with the new method.

  10. Disassembly Properties of Cementitious Finish Joints Using an Induction Heating Method

    PubMed Central

    Ahn, Jaecheol; Noguchi, Takafumi; Kitagaki, Ryoma

    2015-01-01

    Efficient maintenance and upgrading of a building during its lifecycle are difficult because a cementitious finish uses materials and parts with low disassembly properties. Additionally, the reuse and recycling processes during building demolition also present numerous problems from the perspective of environmental technology. In this study, an induction heating (IH) method was used to disassemble cementitious finish joints, which are widely used to join building members and materials. The IH rapidly and selectively heated and weakened these joints. The temperature elevation characteristics of the cementitious joint materials were measured as a function of several resistor types, including wire meshes and punching metals, which are usually used for cementitious finishing. The disassembly properties were evaluated through various tests using conductive resistors in cementitious joints such as mortar. When steel fiber, punching metal, and wire mesh were used as conductive resistors, the cementitious modifiers could be weakened within 30 s. Cementitious joints with conductive resistors also showed complete disassembly with little residual bond strength.

  11. A new and superior ultrafine cementitious grout

    SciTech Connect

    Ahrens, E.H.

    1997-04-01

    Sealing fractures in nuclear waste repositories concerns all programs investigating deep burial as a means of disposal. Because the most likely mechanism for contaminant migration is by dissolution and movement through groundwater, sealing programs are seeking low-viscosity sealants that are chemically, mineralogically, and physically compatible with the host rock. This paper presents the results of collaborative work directed by Sandia National Laboratories (SNL) and supported by Whiteshell Laboratories, operated by Atomic Energy of Canada, Ltd. The work was undertaken in support of the Waste Isolation Pilot Plant (WIPP), an underground nuclear waste repository located in a salt formation east of Carlsbad, NM. This effort addresses the technology associated with long-term isolation of nuclear waste in a natural salt medium. The work presented is part of the WIPP plugging and sealing program, specifically the development and optimization of an ultrafine cementitious grout that can be injected to lower excessive, strain-induced hydraulic conductivity in the fractured rock termed the Disturbed Rock Zone (DRZ) surrounding underground excavations. Innovative equipment and procedures employed in the laboratory produced a usable cement-based grout; 90% of the particles were smaller than 8 microns and the average particle size was 4 microns. The process involved simultaneous wet pulverization and mixing. The grout was used for a successful in situ test underground at the WIPP. Injection of grout sealed microfractures as small as 6 microns (and in one rare instance, 3 microns) and lowered the gas transmissivity of the DRZ by up to three orders of magnitude. Following the WIPP test, additional work produced an improved version of the grout containing particles 90% smaller than 5 microns and averaging 2 microns. This grout will be produced in dry form, ready for the mixer.

  12. Description and evaluation of the Community Multiscale Air Quality (CMAQ) modeling system version 5.1

    NASA Astrophysics Data System (ADS)

    Wyat Appel, K.; Napelenok, Sergey L.; Foley, Kristen M.; Pye, Havala O. T.; Hogrefe, Christian; Luecken, Deborah J.; Bash, Jesse O.; Roselle, Shawn J.; Pleim, Jonathan E.; Foroutan, Hosein; Hutzell, William T.; Pouliot, George A.; Sarwar, Golam; Fahey, Kathleen M.; Gantt, Brett; Gilliam, Robert C.; Heath, Nicholas K.; Kang, Daiwen; Mathur, Rohit; Schwede, Donna B.; Spero, Tanya L.; Wong, David C.; Young, Jeffrey O.

    2017-04-01

    The Community Multiscale Air Quality (CMAQ) model is a comprehensive multipollutant air quality modeling system developed and maintained by the US Environmental Protection Agency's (EPA) Office of Research and Development (ORD). Recently, version 5.1 of the CMAQ model (v5.1) was released to the public, incorporating a large number of science updates and extended capabilities over the previous release version of the model (v5.0.2). These updates include the following: improvements in the meteorological calculations in both CMAQ and the Weather Research and Forecast (WRF) model used to provide meteorological fields to CMAQ, updates to the gas and aerosol chemistry, revisions to the calculations of clouds and photolysis, and improvements to the dry and wet deposition in the model. Sensitivity simulations isolating several of the major updates to the modeling system show that changes to the meteorological calculations result in enhanced afternoon and early evening mixing in the model, periods when the model historically underestimates mixing. This enhanced mixing results in higher ozone (O3) mixing ratios on average due to reduced NO titration, and lower fine particulate matter (PM2. 5) concentrations due to greater dilution of primary pollutants (e.g., elemental and organic carbon). Updates to the clouds and photolysis calculations greatly improve consistency between the WRF and CMAQ models and result in generally higher O3 mixing ratios, primarily due to reduced cloudiness and attenuation of photolysis in the model. Updates to the aerosol chemistry result in higher secondary organic aerosol (SOA) concentrations in the summer, thereby reducing summertime PM2. 5 bias (PM2. 5 is typically underestimated by CMAQ in the summer), while updates to the gas chemistry result in slightly higher O3 and PM2. 5 on average in January and July. Overall, the seasonal variation in simulated PM2. 5 generally improves in CMAQv5.1 (when considering all model updates), as simulated PM2. 5

  13. Multi-scale Eulerian model within the new National Environmental Modeling System

    NASA Astrophysics Data System (ADS)

    Janjic, Zavisa; Janjic, Tijana; Vasic, Ratko

    2010-05-01

    The unified Non-hydrostatic Multi-scale Model on the Arakawa B grid (NMMB) is being developed at NCEP within the National Environmental Modeling System (NEMS). The finite-volume horizontal differencing employed in the model preserves important properties of differential operators and conserves a variety of basic and derived dynamical and quadratic quantities. Among these, conservation of energy and enstrophy improves the accuracy of nonlinear dynamics of the model. Within further model development, advection schemes of fourth order of formal accuracy have been developed. It is argued that higher order advection schemes should not be used in the thermodynamic equation in order to preserve consistency with the second order scheme used for computation of the pressure gradient force. Thus, the fourth order scheme is applied only to momentum advection. Three sophisticated second order schemes were considered for upgrade. Two of them, proposed in Janjic(1984), conserve energy and enstrophy, but with enstrophy calculated differently. One of them conserves enstrophy as computed by the most accurate second order Laplacian operating on stream function. The other scheme conserves enstrophy as computed from the B grid velocity. The third scheme (Arakawa 1972) is arithmetic mean of the former two. It does not conserve enstrophy strictly, but it conserves other quadratic quantities that control the nonlinear energy cascade. Linearization of all three schemes leads to the same second order linear advection scheme. The second order term of the truncation error of the linear advection scheme has a special form so that it can be eliminated by simply preconditioning the advected quantity. Tests with linear advection of a cone confirm the advantage of the fourth order scheme. However, if a localized, large amplitude and high wave-number pattern is present in initial conditions, the clear advantage of the fourth order scheme disappears. In real data runs, problems with noisy data may

  14. Development of a multi-scale data assimilation system for model-observation integration and climate model evaluation (Invited)

    NASA Astrophysics Data System (ADS)

    Li, Z.; Liu, Y.; Lin, W.; Vogelmann, A. M.; Feng, S.; Fridlind, A. M.

    2013-12-01

    To improve our understanding and the representation of subgrid processes in climate models, an increasing number of ground-based long-term observing systems have been established. These systems focus on detailed measurements over a domain of a typical climate model grid size. An example is the US DOE Atmospheric Radiation Measurement (ARM) program, which has been collecting data related to radiation, clouds and precipitation at three primary sites, the Southern Great Plains (SGP) of the USA, the North Slope of Alaska, and the Tropical West Pacific, for approximately 20 years. A well-established approach to use ARM-like measurements in climate model evaluation is jointly using the Single Column Model (SCM), Cloud Resolving Models (CRMs), and/or large eddy simulations (LESs). To enhance the effectiveness of this approach, we have developed multi-scale data assimilation (MS-DA) system on top of the NCEP Gridpoint Statistical Interpolation (GSI) System and implemented in the Weather Research and Forecasting (WRF) model at the cloud resolving resolution (WRF-CRM) over the ARM Climate Research Facility's Southern Great Plains (SGP) site. It is demonstrated that the MS-DA effectively assimilate the dense ARM in-situ observations and high-resolution satellite data, thus significantly reducing uncertainties in the WRF CRM simulation. We have used the WRF CRM simulation constrained by the MS-DA to derive multi-scale forcing that is used to drive SCMs, CRMs, and LESs, expand the large scale forcing parameters to hydrometeors that are not provided in the existing continuous forcing product, and characterize dependency of large-scale forcing on domain-size that represents SCM grid-sizes, sub-grid processes, and cloud-regimes.

  15. Multiscale simulation of time-dependent thermal transpiration in large-scale systems

    NASA Astrophysics Data System (ADS)

    Lockerby, Duncan A.; Patronis, Alexander; Borg, Matthew K.; Reese, Jason M.

    2014-11-01

    We describe the development of an efficient hybrid continuum-molecular approach for simulating non-isothermal, low-speed, internal rarefied gas flows, both in time and space. This is applied to transient flow in macro-scale Knudsen compressors, which is governed by both rarefied gas and continuum fluid dynamics. The method is an extension of the hybrid approach presented by Patronis et al. [J. Comp. Phys. 255, 558 (2013)], which is based on the framework originally proposed by Borg et al. [J. Comp. Phys. 233, 400 (2013)] for the simulation of micro/nano flows of high-aspect-ratio. The efficiency of the multiscale method allows the investigation of alternative Knudsen-compressor configurations to be undertaken. A comparison is made with published experimental data of the transient response (of pressure) in differentially heated reservoirs suddenly connected by a micro capillary. The multiscale simulation results compare very closely to the experimental data and are obtained at a fraction of the cost of a full kinetic or molecular solution. Recommendations for future development and opportunities are discussed. This work is financially supported in the UK by EPSRC Programme Grant EP/I011927/1 and EPSRC Grants EP/K038664/1 and EP/K038621/1.

  16. Non-linear direct multi-scale image enhancement based on the luminance and contrast masking characteristics of the human visual system.

    PubMed

    Nercessian, Shahan C; Panetta, Karen A; Agaian, Sos S

    2013-09-01

    Image enhancement is a crucial pre-processing step for various image processing applications and vision systems. Many enhancement algorithms have been proposed based on different sets of criteria. However, a direct multi-scale image enhancement algorithm capable of independently and/or simultaneously providing adequate contrast enhancement, tonal rendition, dynamic range compression, and accurate edge preservation in a controlled manner has yet to be produced. In this paper, a multi-scale image enhancement algorithm based on a new parametric contrast measure is presented. The parametric contrast measure incorporates not only the luminance masking characteristic, but also the contrast masking characteristic of the human visual system. The formulation of the contrast measure can be adapted for any multi-resolution decomposition scheme in order to yield new human visual system-inspired multi-scale transforms. In this article, it is exemplified using the Laplacian pyramid, discrete wavelet transform, stationary wavelet transform, and dual-tree complex wavelet transform. Consequently, the proposed enhancement procedure is developed. The advantages of the proposed method include: 1) the integration of both the luminance and contrast masking phenomena; 2) the extension of non-linear mapping schemes to human visual system inspired multi-scale contrast coefficients; 3) the extension of human visual system-based image enhancement approaches to the stationary and dual-tree complex wavelet transforms, and a direct means of; 4) adjusting overall brightness; and 5) achieving dynamic range compression for image enhancement within a direct multi-scale enhancement framework. Experimental results demonstrate the ability of the proposed algorithm to achieve simultaneous local and global enhancements.

  17. Ancient analogues concerning stability and durability of cementitious wasteform

    SciTech Connect

    Jiang, W.; Roy, D.M.

    1994-12-31

    The history of cementitious materials goes back to ancient times. The Greeks and Romans used calcined limestone and later developed pozzolanic cement by grinding together lime and volcanic ash called {open_quotes}pozzolan{close_quotes} which was first found near Port Pozzuoli, Italy. The ancient Chinese used lime-pozzolanic mixes to build the Great Wall. The ancient Egyptians used calcined impure gypsum to build the Great Pyramid of Cheops. The extraordinary stability and durability of these materials has impressed us, when so much dramatically damaged infrastructure restored by using modern portland cement now requires rebuilding. Stability and durability of cementitious materials have attracted intensive research interest and contractors` concerns, as does immobilization of radioactive and hazardous industrial waste in cementitious materials. Nuclear waste pollution of the environment and an acceptable solution for waste management and disposal constitute among the most important public concerns. The analogy of ancient cementitious materials to modern Portland cement could give us some clues to study their stability and durability. This present study examines selected results of studies of ancient building materials from France, Italy, China, and Egypt, combined with knowledge obtained from the behavior of modern portland cement to evaluate the potential for stability and durability of such materials in nuclear waste forms.

  18. Phosphate Ions - Does Exposure Lead to Degradation of Cementitious Materials?

    SciTech Connect

    Naus, Dan J; Mattus, Catherine H; Dole, Leslie Robert

    2008-01-01

    An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a "bench-scale" laboratory investigation. Results indicate that no harmful interactions occur between phosphate ions and cememtitious materials unless phosphates are present in form of phosphoric acid.

  19. The Expanded Capabilities Of The Cementitious Barriers Partnership Software Toolbox Version 2.0 - 14331

    SciTech Connect

    Burns, Heather; Flach, Greg; Smith, Frank; Langton, Christine; Brown, Kevin; Kosson, David; Samson, Eric; Mallick, Pramod

    2014-01-10

    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. The CBP Software Toolbox – “Version 1.0” was released early in FY2013 and was used to support DOE-EM performance assessments in evaluating various degradation mechanisms that included sulfate attack, carbonation and constituent leaching. The sulfate attack analysis predicted the extent and damage that sulfate ingress will have on concrete vaults over extended time (i.e., > 1000 years) and the carbonation analysis provided concrete degradation predictions from rebar corrosion. The new release “Version 2.0” includes upgraded carbonation software and a new software module to evaluate degradation due to chloride attack. Also included in the newer version are a dual regime module allowing evaluation of contaminant release in two regimes – both fractured and un-fractured. The integrated software package has also been upgraded with new plotting capabilities and many other features that increase the “user-friendliness” of the package. Experimental work has been generated to provide data to calibrate the models to improve the credibility of the analysis and reduce the uncertainty. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to or longer than 100 years for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox is and will continue to produce tangible benefits to the working DOE

  20. Modeling Complex Biological Flows in Multi-Scale Systems using the APDEC Framework

    SciTech Connect

    Trebotich, D

    2006-06-24

    We have developed advanced numerical algorithms to model biological fluids in multiscale flow environments using the software framework developed under the SciDAC APDEC ISIC. The foundation of our computational effort is an approach for modeling DNA-laden fluids as ''bead-rod'' polymers whose dynamics are fully coupled to an incompressible viscous solvent. The method is capable of modeling short range forces and interactions between particles using soft potentials and rigid constraints. Our methods are based on higher-order finite difference methods in complex geometry with adaptivity, leveraging algorithms and solvers in the APDEC Framework. Our Cartesian grid embedded boundary approach to incompressible viscous flow in irregular geometries has also been interfaced to a fast and accurate level-sets method within the APDEC Framework for extracting surfaces from volume renderings of medical image data and used to simulate cardio-vascular and pulmonary flows in critical anatomies.

  1. Quantifying moisture transport in cementitious materials using neutron radiography

    NASA Astrophysics Data System (ADS)

    Lucero, Catherine L.

    A portion of the concrete pavements in the US have recently been observed to have premature joint deterioration. This damage is caused in part by the ingress of fluids, like water, salt water, or deicing salts. The ingress of these fluids can damage concrete when they freeze and expand or can react with the cementitious matrix causing damage. To determine the quality of concrete for assessing potential service life it is often necessary to measure the rate of fluid ingress, or sorptivity. Neutron imaging is a powerful method for quantifying fluid penetration since it can describe where water has penetrated, how quickly it has penetrated and the volume of water in the concrete or mortar. Neutrons are sensitive to light atoms such as hydrogen and thus clearly detect water at high spatial and temporal resolution. It can be used to detect small changes in moisture content and is ideal for monitoring wetting and drying in mortar exposed to various fluids. This study aimed at developing a method to accurately estimate moisture content in mortar. The common practice is to image the material dry as a reference before exposing to fluid and normalizing subsequent images to the reference. The volume of water can then be computed using the Beer-Lambert law. This method can be limiting because it requires exact image alignment between the reference image and all subsequent images. A model of neutron attenuation in a multi-phase cementitious composite was developed to be used in cases where a reference image is not available. The attenuation coefficients for water, un-hydrated cement, and sand were directly calculated from the neutron images. The attenuation coefficient for the hydration products was then back-calculated. The model can estimate the degree of saturation in a mortar with known mixture proportions without using a reference image for calculation. Absorption in mortars exposed to various fluids (i.e., deionized water and calcium chloride solutions) were investigated

  2. Method for the production of cementitious compositions and aggregate derivatives from said compositions, and cementitious compositions and aggregates produced thereby

    DOEpatents

    Minnick, L. John

    1983-01-01

    The present invention relates to a method for preparing synthetic shaped cementitious compositions having high quality even without the addition of high energy binders, such as portland cement, through the use of the spent residue from a fluidized combustion bed of the type wherein limestone particles are suspended in a fluidized medium and sulfur oxides are captured, and pulverized coal fly ash.

  3. RC beams shear-strengthened with fabric-reinforced-cementitious-matrix (FRCM) composite

    NASA Astrophysics Data System (ADS)

    Loreto, Giovanni; Babaeidarabad, Saman; Leardini, Lorenzo; Nanni, Antonio

    2015-12-01

    The interest in retrofit/rehabilitation of existing concrete structures has increased due to degradation and/or introduction of more stringent design requirements. Among the externally-bonded strengthening systems fiber-reinforced polymers is the most widely known technology. Despite its effectiveness as a material system, the presence of an organic binder has some drawbacks that could be addressed by using in its place a cementitious binder as in fabric-reinforced cementitious matrix (FRCM) systems. The purpose of this paper is to evaluate the behavior of reinforced concrete (RC) beams strengthened in shear with U-wraps made of FRCM. An extensive experimental program was undertaken in order to understand and characterize this composite when used as a strengthening system. The laboratory results demonstrate the technical viability of FRCM for shear strengthening of RC beams. Based on the experimental and analytical results, FRCM increases shear strength but not proportionally to the number of fabric plies installed. On the other hand, FRCM failure modes are related with a high consistency to the amount of external reinforcement applied. Design considerations based on the algorithms proposed by ACI guidelines are also provided.

  4. Overview of the Multiscale Epidemiologic/Economic Simulation and Analysis (MESA) Decision Support System

    SciTech Connect

    Speck, D E

    2008-04-28

    The Multiscale Epidemiologic/Economic Simulation and Analysis (MESA) Decision Support System (DSS) is the product of investments that began in FY05 by the Department of Homeland Security (DHS) Science and Technology Directorate and continue today with joint funding by both DHS and the US Department of Agriculture (USDA). The DSS consists of a coupled epidemiologic/economic model, a standalone graphical user interface (GUI) that supports both model setup and post-analysis, and a Scenario Bank archive to store all content related to foreign animal disease (FAD) studies. The MESA epi model is an object-oriented, agent-based, stochastic, spatio-temporal simulator that parametrically models FAD outbreaks and response strategies from initial disease introduction to conclusion over local, regional, and national scales. Through its output database, the epi model couples to an economic model that calculates farm-level impacts from animal infections, responsive control strategies and loss of trade. The MESA architecture contains a variety of internal models that implement the major components of the epi simulation, including disease introduction, intra-herd spread, inter-herd spread (direct and indirect), detection, and various control strategies (movement restrictions, culling, vaccination) in a highly configurable and extensible fashion. MESA development was originally focused to support investigations into the economic and agricultural industry impacts associated with Foot-and-Mouth Disease (FMD outbreaks). However, it has been adapted to other FADs such has Highly Pathogenic Avian Influenza (HPAI), Classical Swine Fever (CSF) and Exotic Newcastle Disease (END). The MESA model is highly parameterized and employs an extensible architecture that permits straightforward addition of new component models (e.g., alternative disease spread approaches) when necessary. Since its inception, MESA has been developed with a requirement to enable simulation of the very large scale

  5. Coupling NASA Advanced Multi-Scale Modeling and Concurrent Visualization Systems for Improving Predictions of High-Impact Tropical Weather (CAMVis)

    NASA Astrophysics Data System (ADS)

    Shen, B.; Tao, W.; Henze, C.

    2010-12-01

    Among scenarios in Decadal Survey Missions (DSM) report (NRC, 2007), "Extreme Event Warning" is one of top priority scenarios. This focuses on "discovering predictive relationships between meteorological and climatologically events and less obvious precursor conditions from massive data set." To achieve this, our approach is to deploy the "Coupled Advanced Multi-Scale Modeling and Concurrent Visualization Systems (CAMVis)" by (1) integrating the existing NASA technologies such as NASA multi- scale model system, Goddard Cloud Ensemble model, the Global Mesoscale Model, and the concurrent visualization systems; (2) improving parallel scalability of the coupled multi-scale modeling system to take full advantage of the next generation peta-scale supercomputers; (3) significantly streamlining data flow for fast processing and 3D visualizations; (4) developing visualization modules for fusion of NASA TRMM precipitation and QuikSCAT winds. In this study, we will discuss our current progress and future tasks to support the DSM missions.

  6. EMAPS: An Efficient Multiscale Approach to Plasma Systems with Non-MHD Scale Effects

    SciTech Connect

    Omelchenko, Yuri A.

    2016-08-08

    we have developed a novel Event-driven Multiscale Asynchronous Parallel Simulation (EMAPS) technology that replaces time stepping with self-adaptive update events. Local calculations are carried out only on an “as needed basis”. EMAPS (i) guarantees accurate and stable processing of physical variables in time accurate simulations, and (ii) eliminates unnecessary computation. Applying EMAPS to the hybrid model has resulted in the development of a unique parallel code, dimension-independent (compile-time-configurable) HYPERS (Hybrid Parallel Event-Resolved Simulator) that scales to hundreds of thousands of parallel processors. HYPERS advances electromagnetic fields and particles asynchronously on time scales determined by local physical laws and mesh properties. To achieve high computational accuracy in complex device geometries, HYPERS employs high-fidelity Cartesian grids with masked conductive cells. The HYPERS model includes multiple ion species, energy and momentum conserving ion-ion collisions, and provides a number of approximations for plasma resistivity and vacuum regions. Both local and periodic boundary conditions are allowed. The HYPERS solver preserves zero divergence of magnetic field. The project has demonstrated HYPERS capabilities on a number of applications of interest to fusion and astrophysical plasma physics applications listed below. 1. Theta-pinch formation of FRCs The formation, spontaneous spin-up, and stability of theta-pinch formed field-reversed configurations have been studied self-consistently in 3D. The end-to-end hybrid simulations reveal poloidal profiles of implosion-driven fast toroidal plasma rotation and demonstrate three discharge regimes as a function of experimental parameters: the decaying stable configuration, the tilt unstable configuration, and the nonlinear evolution of a fast growing tearing mode. 2. FRC collisions with magnetic mirrors Interactions of fast plasma streams and objects with magnetic obstacles (dipoles

  7. Cementitious Barriers Partnership FY2013 End-Year Report

    SciTech Connect

    Flach, G. P.; Langton, C. A.; Burns, H. H.; Smith, F. G.; Kosson, D. S.; Brown, K. G.; Samson, E.; Meeussen, J. C.L.; van der Sloot, H. A.; Garboczi, E. J.

    2013-11-01

    In FY2013, the Cementitious Barriers Partnership (CBP) demonstrated continued tangible progress toward fulfilling the objective of developing a set of software tools to improve understanding and prediction of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. In November 2012, the CBP released “Version 1.0” of the CBP Software Toolbox, a suite of software for simulating reactive transport in cementitious materials and important degradation phenomena. In addition, the CBP completed development of new software for the “Version 2.0” Toolbox to be released in early FY2014 and demonstrated use of the Version 1.0 Toolbox on DOE applications. The current primary software components in both Versions 1.0 and 2.0 are LeachXS/ORCHESTRA, STADIUM, and a GoldSim interface for probabilistic analysis of selected degradation scenarios. The CBP Software Toolbox Version 1.0 supports analysis of external sulfate attack (including damage mechanics), carbonation, and primary constituent leaching. Version 2.0 includes the additional analysis of chloride attack and dual regime flow and contaminant migration in fractured and non-fractured cementitious material. The LeachXS component embodies an extensive material property measurements database along with chemical speciation and reactive mass transport simulation cases with emphasis on leaching of major, trace and radionuclide constituents from cementitious materials used in DOE facilities, such as Saltstone (Savannah River) and Cast Stone (Hanford), tank closure grouts, and barrier concretes. STADIUM focuses on the physical and structural service life of materials and components based on chemical speciation and reactive mass transport of major cement constituents and aggressive species (e.g., chloride, sulfate, etc.). THAMES is a planned future CBP Toolbox component focused on simulation of the microstructure of cementitious materials and calculation of resultant

  8. LONG-TERM TECHNETIUM INTERACTIONS WITH REDUCING CEMENTITIOUS MATERIALS

    SciTech Connect

    Kaplan, D.; Lilley, M.; Almond, P.; Powell, B.

    2011-03-15

    Technetium is among the key risk drivers at the Saltstone Facility. The way that it is immobilized in this cementitious waste form is by converting its highly mobile Tc(VII) form to a much less mobile Tc(IV) form through reduction by the cement's blast furnace slag. This report includes a review of published data and experimental results dealing with Tc leaching from Portland cement waste forms. The objectives for the literature study were to document previous reports of Tc interactions with slag-containing cementitious materials. The objectives for the laboratory study were to measure Tc-saltstone Kd values under reducing conditions. From the literature it was concluded: (1) Spectroscopic evidence showed that when Tc(IV) in a slag-cement was exposed to an oxidizing environment, it will convert to the more mobile Tc(VII) species within a short time frame, 2.5 years. (2) SRS saltstone will reduce Tc(VII) in the absence of NaS or sodium dithionite in a reducing atmosphere. (3) Only trace concentrations of atmospheric oxygen (30 to 60 ppm O{sub 2}; Eh 120 mV) at the high pH levels of cementitious systems is required to maintain Tc as Tc(VII). (4) Experimental conditions must be responsible for wide variability of measured K{sub d} values, such that they are either very low, {approx}1 mL/g, or they are very high {approx}1000 mL/g, suggesting that Tc(VII) or Tc(IV) dominate the systems. Much of this variability appears to be the result of experimental conditions, especially direct controls of oxygen contact with the sample. (5) A field study conducted at SRS in the 1980s indicated that a slag-saltstone immobilized Tc for 2.5 years. Below background concentrations of Tc leached out of the slag-containing saltstone, whereas Tc leached out of the slag-free saltstone at the rate of nitrate loss. One possible explanation for the immobilization of Tc in this study was that the slag-saltstone maintained reducing conditions within the core of the 55-gallon sample, whereas in

  9. Tensile strength of cementitious materials under triaxial loading

    NASA Astrophysics Data System (ADS)

    Tsubota, Shuji

    1998-11-01

    A general tension-compression-compression (sigmasb1, sigmasb2=sigmasb3) failure criterion for brittle materials is mathematically developed using FEM analysis and experimentally verified by use of the cementitious composite axial tensile test (CCATT). This tensile failure criterion is based on the stress concentration derived from the classical theory of elasticity. This analytical approach shows the upper bound of the tension-compression-compression failure surface for brittle materials. Since the CCATT applies confining hydraulic pressure, a tensile specimen is subjected to triaxial loading defined by the principal stress ratio sigmasb1/|sigmasb2|. When lateral pressure increases, tensile strength decreases; therefore, stress concentration is defined as a function of the principal stress ratio. The model has three distinct regions of behavior corresponding to the principal stress ratio, 0≤sigmasb1/|sigmasb2|<0.9 (high-lateral pressure), 0.9≤sigmasb1/|sigmasb2|<3.0 (medium-lateral pressure), 3.0≤sigmasb1/|sigmasb2| (low-lateral pressure). The experimental failure line shows true tensile strength of cementitious materials under low-lateral pressure. The predicted nominal stress fsb{ta} with large size specimens for the CCATT is written as$fsb{ta}=gamma*{1/{Kt}}*alpha* pwhere gamma$ is the size effect obtained by experimental results; Kt is the stress concentration factor derived from triaxial loading. Tensile strength values from the CCATT are compared to experimental results from other tests such as the uniaxial tensile test and the split cylinder test. CCATT results are analyzed using Weibull theory to measure material reliability and to develop characteristic stresses for construction design. Failure analysis using fractography was conducted on fractured cementitious materials and composites. The failure analysis on test specimens correlated well with FEM stress distributions and with the principal stress ratio. The observed fracture behavior (fracture

  10. Cementitious Grout for Closing SRS High Level Waste Tanks - 12315

    SciTech Connect

    Langton, C.A.; Stefanko, D.B.; Burns, H.H.; Waymer, J.; Mhyre, W.B.; Herbert, J.E.; Jolly, J.C. Jr.

    2012-07-01

    In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F and 19-F. These tanks were constructed in the late 1950's and received low-heat waste and do not contain cooling coils. Operational closure of Tanks 18-F and 19-F is intended to be consistent with the applicable requirements of the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and will be performed in accordance with South Carolina Department of Health and Environmental Control (SCDHEC). The closure will physically stabilize two 4.92E+04 cubic meter (1.3 E+06 gallon) carbon steel tanks and isolate and stabilize any residual contaminants left in the tanks. Ancillary equipment abandoned in the tanks will also be filled to the extent practical. A Performance Assessment (PA) has been developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closure of the F-Area Tank Farm (FTF) waste tanks. Next generation flowable, zero-bleed cementitious grouts were designed, tested, and specified for closing Tanks 18-F and 19-F and for filling the abandoned equipment. Fill requirements were developed for both the tank and equipment grouts. All grout formulations were required to be alkaline with a pH of 12.4 and to be chemically reducing with a reduction potential (Eh) of -200 to -400. Grouts with this chemistry stabilize potential contaminants of concern. This was achieved by including Portland cement and Grade 100 slag in the mixes, respectively. Ingredients and proportions of cementitious reagents were selected and adjusted to support the mass placement strategy developed by

  11. Extrinsic calibration of a fringe projection sensor based on a zoom stereo microscope in an automatic multiscale measurement system

    NASA Astrophysics Data System (ADS)

    Gronle, Marc; Lyda, Wolfram; Burla, Avinash; Osten, Wolfgang

    2012-04-01

    Multi scale systems offer the opportunity to balance the conflict between execution time, measurement volume and resolution for the inspection of highly complex surface profiles. An example of such a task is the inspection of gears. At first, the coarse position and form of the specimen is registered by a sensor measuring with comparatively low resolution but a large field of view. Possible defects near to the resolution limit are indicated and new regions of interest for higher resolved measurements are identified. As prerequisite for a successful multi-scale inspection, every sampled data set, acquired in different scales and at varying positions, must be registered in one global data model. This is only possible if the extrinsic coordinate transform from the sensor's internal coordinate system to the common, global coordinate system of the inspected object and its uncertainties are known. In this paper, we present an approach for the extrinsic calibration using the example of a multi-zoom fringe projection sensor mounted on a multi-axes measurement system. Finally we show the measurement result of a gear, where several sampled patches are merged together into one point cloud with the aid of the presented calibration.

  12. Investigating the Complex Chemistry of Functional Energy Storage Systems: The Need for an Integrative, Multiscale (Molecular to Mesoscale) Perspective.

    PubMed

    Abraham, Alyson; Housel, Lisa M; Lininger, Christianna N; Bock, David C; Jou, Jeffrey; Wang, Feng; West, Alan C; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

    2016-06-22

    Electric energy storage systems such as batteries can significantly impact society in a variety of ways, including facilitating the widespread deployment of portable electronic devices, enabling the use of renewable energy generation for local off grid situations and providing the basis of highly efficient power grids integrated with energy production, large stationary batteries, and the excess capacity from electric vehicles. A critical challenge for electric energy storage is understanding the basic science associated with the gap between the usable output of energy storage systems and their theoretical energy contents. The goal of overcoming this inefficiency is to achieve more useful work (w) and minimize the generation of waste heat (q). Minimization of inefficiency can be approached at the macro level, where bulk parameters are identified and manipulated, with optimization as an ultimate goal. However, such a strategy may not provide insight toward the complexities of electric energy storage, especially the inherent heterogeneity of ion and electron flux contributing to the local resistances at numerous interfaces found at several scale lengths within a battery. Thus, the ability to predict and ultimately tune these complex systems to specific applications, both current and future, demands not just parametrization at the bulk scale but rather specific experimentation and understanding over multiple length scales within the same battery system, from the molecular scale to the mesoscale. Herein, we provide a case study examining the insights and implications from multiscale investigations of a prospective battery material, Fe3O4.

  13. Investigating the Complex Chemistry of Functional Energy Storage Systems: The Need for an Integrative, Multiscale (Molecular to Mesoscale) Perspective

    PubMed Central

    2016-01-01

    Electric energy storage systems such as batteries can significantly impact society in a variety of ways, including facilitating the widespread deployment of portable electronic devices, enabling the use of renewable energy generation for local off grid situations and providing the basis of highly efficient power grids integrated with energy production, large stationary batteries, and the excess capacity from electric vehicles. A critical challenge for electric energy storage is understanding the basic science associated with the gap between the usable output of energy storage systems and their theoretical energy contents. The goal of overcoming this inefficiency is to achieve more useful work (w) and minimize the generation of waste heat (q). Minimization of inefficiency can be approached at the macro level, where bulk parameters are identified and manipulated, with optimization as an ultimate goal. However, such a strategy may not provide insight toward the complexities of electric energy storage, especially the inherent heterogeneity of ion and electron flux contributing to the local resistances at numerous interfaces found at several scale lengths within a battery. Thus, the ability to predict and ultimately tune these complex systems to specific applications, both current and future, demands not just parametrization at the bulk scale but rather specific experimentation and understanding over multiple length scales within the same battery system, from the molecular scale to the mesoscale. Herein, we provide a case study examining the insights and implications from multiscale investigations of a prospective battery material, Fe3O4. PMID:27413781

  14. Multi-Scale Modeling and Probabilistic Assessment of Electrical Power and Dependent Systems' Resilience to Extreme Events

    NASA Astrophysics Data System (ADS)

    Backhaus, S.; Pasqualini, D.; Crawford, T.; Ewers, M.; Tasseff, B.; Ambrosiano, J.; Linger, S.; Roberts, R.; Bent, R.; Barnes, A.

    2016-12-01

    Electrical power systems and infrastructure systems that depend on electric power are deployed and operated at spatial scales ranging from individual facilities to cities to regions. The resilience of these systems has evolved naturally under the influence of extreme events. This evolution continues today as systems face more severe and frequent extreme events. Accurately representing the present resilience and future evolution of these systems across such a wide range of scales is both a modeling and computational challenge, especially considering that system evolution may involve new technologies and design approaches where no historical data are available to enable extrapolations. Naïve top-down aggregations of existing electrical power distribution networks will not capture important correlations between previous system hardening and critical dependent systems, leading to inaccurate modeling of current local resilience and costs associated with upgrades to improve local resilience and inaccurate boundary conditions on regional-scale electrical transmission models. Using probabilistic risk analysis approaches for hurricane and ice storm events, we present an integrated multi-scale, multi-sector modeling approach that can model and upscale naturally evolved resilience of fine-scale electrical distribution networks and their dependent critical systems. We use stochastic optimization-based models to predict and upscale potential future evolution driven by existing and emerging technologies. An optimization approach can incorporate human factors and represent potential bias in the resilience adaptation toward different residual risk profiles. We describe the coupling of these new aggregated models of fine-scale electrical power system resilience to models of regional electrical transmission systems and show how resilient regional operational strategies may be adapted to autonomous local resilience upgrades.

  15. A Multi-scale Modeling System: Developments, Applications and Critical Issues

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Chern, Jiundar; Atlas, Robert; Randall, David; Lin, Xin; Khairoutdinov, Marat; Li, Jui-Lin; Waliser, Duane E.; Hou, Arthur; Peters-Lidard, Christa; hide

    2006-01-01

    A multi-scale modeling framework (MMF), which replaces the conventional cloud parameterizations with a cloud-resolving model (CRM) in each grid column of a GCM, constitutes a new and promising approach. The MMF can provide for global coverage and two-way interactions between the CRMs and their parent GCM. The GCM allows global coverage and the CRM allows explicit simulation of cloud processes and their interactions with radiation and surface processes. A new MMF has been developed that is based the Goddard finite volume GCM (fvGCM) and the Goddard Cumulus Ensemble (GCE) model. This Goddard MMF produces many features that are similar to another MMF that was developed at Colorado State University (CSU), such as an improved .surface precipitation pattern, better cloudiness, improved diurnal variability over both oceans and continents, and a stronger, propagating Madden-Julian oscillation (MJO) compared to their parent GCMs using conventional cloud parameterizations. Both MMFs also produce a precipitation bias in the western Pacific during Northern Hemisphere summer. However, there are also notable differences between two MMFs. For example, the CSU MMF simulates less rainfall over land than its parent GCM. This is why the CSU MMF simulated less overall global rainfall than its parent GCM. The Goddard MMF overestimates global rainfall because of its oceanic component. Some critical issues associated with the Goddard MMF are presented in this paper.

  16. Multi-scale exciton and electron transfer in multi-level donor-acceptor systems

    NASA Astrophysics Data System (ADS)

    Gurvitz, Shmuel; Nesterov, Alexander I.; Berman, Gennady P.

    2017-09-01

    We study theoretically the noise-assisted quantum exciton (electron) transfer (ET) in bio-complexes consisting of a single-level electron donor and an acceptor which has a complicated internal structure, and is modeled by many electron energy levels. Interactions are included between the donor and the acceptor energy levels and with the protein-solvent noisy environment. Different regions of parameters are considered, which characterize (i) the number of the acceptor levels, (ii) the acceptor ‘band-width’, and (iii) the amplitude of noise and its correlation time. Under some conditions, we derive analytical expressions for the ET rate and efficiency. We obtain equal occupation of all levels at large times, independent of the structure of the acceptor band and the noise parameters, but under the condition of non-degeneracy of the acceptor energy levels. We discuss the multi-scale dynamics of the acceptor population, and the accompanying effect of quantum coherent oscillations. We also demonstrate that for a large number of levels in the acceptor band, the efficiency of ET can be close to 100%, for both downhill and uphill transitions and for sharp and flat redox potentials.

  17. Multi-scale models of grassland passerine abundance in a fragmented system in Wisconsin

    USGS Publications Warehouse

    Renfrew, R.B.; Ribic, C.A.

    2008-01-01

    Fragmentation of grasslands has been implicated in grassland bird population declines. Multi-scale models are being increasingly used to assess potential factors that influence grassland bird presence, abundance, and productivity. However, studies rarely assess fragmentation metrics, and seldom evaluate more than two scales or interactions among scales. We evaluated the relative importance of characteristics at multiple scales to patterns in relative abundance of Savannah Sparrow (Passerculus sandwichensis), Grasshopper Sparrow (Ammodramus savannarum), Eastern Meadowlark (Sturnella magna), and Bobolink (Dolichonyx oryzivorus). We surveyed birds in 74 southwestern Wisconsin pastures from 1997 to 1999 and compared models with explanatory variables from multiple scales: within-patch vegetation structure (microhabitat), patch (macrohabitat), and three landscape extents. We also examined interactions between macrohabitat and landscape factors. Core area of pastures was an important predictor of relative abundance, and composition of the landscape was more important than configuration. Relative abundance was frequently higher in pastures with more core area and in landscapes with more grassland and less wooded area. The direction and strength of the effect of core pasture size on relative abundance changed depending on amount of wooded area in the landscape. Relative abundance of grassland birds was associated with landscape variables more frequently at the 1200-m scale than at smaller scales. To develop better predictive models, parameters at multiple scales and their interactive effects should be included, and results should be evaluated in the context of microhabitat variability, landscape composition, and fragmentation in the study area. ?? 2007 Springer Science+Business Media B.V.

  18. Thermal conductivity of cementitious grouts for geothermal heat pumps. Progress report FY 1997

    SciTech Connect

    Allan, M.L.

    1997-11-01

    Grout is used to seal the annulus between the borehole and heat exchanger loops in vertical geothermal (ground coupled, ground source, GeoExchange) heat pump systems. The grout provides a heat transfer medium between the heat exchanger and surrounding formation, controls groundwater movement and prevents contamination of water supply. Enhanced heat pump coefficient of performance (COP) and reduced up-front loop installation costs can be achieved through optimization of the grout thermal conductivity. The objective of the work reported was to characterize thermal conductivity and other pertinent properties of conventional and filled cementitious grouts. Cost analysis and calculations of the reduction in heat exchanger length that could be achieved with such grouts were performed by the University of Alabama. Two strategies to enhance the thermal conductivity of cementitious grouts were used simultaneously. The first of these was to incorporate high thermal conductivity filler in the grout formulations. Based on previous tests (Allan and Kavanaugh, in preparation), silica sand was selected as a suitable filler. The second strategy was to reduce the water content of the grout mix. By lowering the water/cement ratio, the porosity of the hardened grout is decreased. This results in higher thermal conductivity. Lowering the water/cement ratio also improves such properties as permeability, strength, and durability. The addition of a liquid superplasticizer (high range water reducer) to the grout mixes enabled reduction of water/cement ratio while retaining pumpability. Superplasticizers are commonly used in the concrete and grouting industry to improve rheological properties.

  19. Cementitious binder from fly ash and other industrial wastes

    SciTech Connect

    Singh, M.; Garg, M.

    1999-03-01

    In this paper, investigations were undertaken to formulate cementitious binder by judicious blending of fly ash with Portland cement as well as by admixing fly ash with calcined phosphogypsum, fluorogypsum, lime sludge, and chemical activators of different finenesses. The effect of addition of calcined clay in these types of binders was studied. Data showed that cementitious binders of high compressive strength and water retentivity can be produced. The strength of masonry mortars increased with the addition of chemical activators. The strength development of binders takes place through formation of ettringite. C-S-H, and C{sub 4}AH{sub 13}. The binders are eminently suitable for partial replacement (up to 25%) of the cement in concrete without any detrimental affect on the strength. The results showed that fly ash can be used in the range from 45% to 70% in formulating these binders along with other industrial wastes to help in mitigating environmental pollution.

  20. Temperature variability analysis using wavelets and multiscale entropy in patients with systemic inflammatory response syndrome, sepsis, and septic shock

    PubMed Central

    2012-01-01

    Background Even though temperature is a continuous quantitative variable, its measurement has been considered a snapshot of a process, indicating whether a patient is febrile or afebrile. Recently, other diagnostic techniques have been proposed for the association between different properties of the temperature curve with severity of illness in the Intensive Care Unit (ICU), based on complexity analysis of continuously monitored body temperature. In this study, we tried to assess temperature complexity in patients with systemic inflammation during a suspected ICU-acquired infection, by using wavelets transformation and multiscale entropy of temperature signals, in a cohort of mixed critically ill patients. Methods Twenty-two patients were enrolled in the study. In five, systemic inflammatory response syndrome (SIRS, group 1) developed, 10 had sepsis (group 2), and seven had septic shock (group 3). All temperature curves were studied during the first 24 hours of an inflammatory state. A wavelet transformation was applied, decomposing the signal in different frequency components (scales) that have been found to reflect neurogenic and metabolic inputs on temperature oscillations. Wavelet energy and entropy per different scales associated with complexity in specific frequency bands and multiscale entropy of the whole signal were calculated. Moreover, a clustering technique and a linear discriminant analysis (LDA) were applied for permitting pattern recognition in data sets and assessing diagnostic accuracy of different wavelet features among the three classes of patients. Results Statistically significant differences were found in wavelet entropy between patients with SIRS and groups 2 and 3, and in specific ultradian bands between SIRS and group 3, with decreased entropy in sepsis. Cluster analysis using wavelet features in specific bands revealed concrete clusters closely related with the groups in focus. LDA after wrapper-based feature selection was able to classify

  1. The NASA-Goddard Multi-Scale Modeling Framework - Land Information System: Global Land/atmosphere Interaction with Resolved Convection

    NASA Technical Reports Server (NTRS)

    Mohr, Karen Irene; Tao, Wei-Kuo; Chern, Jiun-Dar; Kumar, Sujay V.; Peters-Lidard, Christa D.

    2013-01-01

    The present generation of general circulation models (GCM) use parameterized cumulus schemes and run at hydrostatic grid resolutions. To improve the representation of cloud-scale moist processes and landeatmosphere interactions, a global, Multi-scale Modeling Framework (MMF) coupled to the Land Information System (LIS) has been developed at NASA-Goddard Space Flight Center. The MMFeLIS has three components, a finite-volume (fv) GCM (Goddard Earth Observing System Ver. 4, GEOS-4), a 2D cloud-resolving model (Goddard Cumulus Ensemble, GCE), and the LIS, representing the large-scale atmospheric circulation, cloud processes, and land surface processes, respectively. The non-hydrostatic GCE model replaces the single-column cumulus parameterization of fvGCM. The model grid is composed of an array of fvGCM gridcells each with a series of embedded GCE models. A horizontal coupling strategy, GCE4fvGCM4Coupler4LIS, offered significant computational efficiency, with the scalability and I/O capabilities of LIS permitting landeatmosphere interactions at cloud-scale. Global simulations of 2007e2008 and comparisons to observations and reanalysis products were conducted. Using two different versions of the same land surface model but the same initial conditions, divergence in regional, synoptic-scale surface pressure patterns emerged within two weeks. The sensitivity of largescale circulations to land surface model physics revealed significant functional value to using a scalable, multi-model land surface modeling system in global weather and climate prediction.

  2. A Multi-Scale Model of the Circulatory System for the Study of Left Ventricular Assist Devices

    NASA Astrophysics Data System (ADS)

    Gohean, J. R.; Moser, R. D.; Bazilevs, Y.; Hughes, T. J. R.

    2006-11-01

    A computer model of the cardiovascular system has been developed to study the hemodynamic effects of a non-pulsatile axial flow left ventricular assist device (LVAD). The model is multi-scale and consists of a distributed quasi-one-dimensional arterial tree, based on integrated Navier-Stokes with a pressure/area state equation representing the compliance of the arteries; and lumped parameter models for the systemic return, pulmonary circulation, coronary circulation, and heart. Physiologically consistent aortic pressure and flow histories have been obtained by including a dynamic aortic valve model that allows back-flow by representing leaflet motion. In addition, a three-dimensional finite element model of the aorta with nonlinear elastic arterial walls can be integrated with the quasi-one-dimensional and lumped parameter models, with the lower fidelity models providing boundary conditions for the detailed model. The three dimensional model allows investigation of the detailed flow characteristics induced by the LVAD. The effect of an LVAD and its implant configuration on the hemodynamics of the cardiovascular system and coronary perfusion are studied for various patient conditions and levels of assist.

  3. A Novel Method to Verify Multilevel Computational Models of Biological Systems Using Multiscale Spatio-Temporal Meta Model Checking

    PubMed Central

    Gilbert, David

    2016-01-01

    Insights gained from multilevel computational models of biological systems can be translated into real-life applications only if the model correctness has been verified first. One of the most frequently employed in silico techniques for computational model verification is model checking. Traditional model checking approaches only consider the evolution of numeric values, such as concentrations, over time and are appropriate for computational models of small scale systems (e.g. intracellular networks). However for gaining a systems level understanding of how biological organisms function it is essential to consider more complex large scale biological systems (e.g. organs). Verifying computational models of such systems requires capturing both how numeric values and properties of (emergent) spatial structures (e.g. area of multicellular population) change over time and across multiple levels of organization, which are not considered by existing model checking approaches. To address this limitation we have developed a novel approximate probabilistic multiscale spatio-temporal meta model checking methodology for verifying multilevel computational models relative to specifications describing the desired/expected system behaviour. The methodology is generic and supports computational models encoded using various high-level modelling formalisms because it is defined relative to time series data and not the models used to generate it. In addition, the methodology can be automatically adapted to case study specific types of spatial structures and properties using the spatio-temporal meta model checking concept. To automate the computational model verification process we have implemented the model checking approach in the software tool Mule (http://mule.modelchecking.org). Its applicability is illustrated against four systems biology computational models previously published in the literature encoding the rat cardiovascular system dynamics, the uterine contractions of labour

  4. A Novel Method to Verify Multilevel Computational Models of Biological Systems Using Multiscale Spatio-Temporal Meta Model Checking.

    PubMed

    Pârvu, Ovidiu; Gilbert, David

    2016-01-01

    Insights gained from multilevel computational models of biological systems can be translated into real-life applications only if the model correctness has been verified first. One of the most frequently employed in silico techniques for computational model verification is model checking. Traditional model checking approaches only consider the evolution of numeric values, such as concentrations, over time and are appropriate for computational models of small scale systems (e.g. intracellular networks). However for gaining a systems level understanding of how biological organisms function it is essential to consider more complex large scale biological systems (e.g. organs). Verifying computational models of such systems requires capturing both how numeric values and properties of (emergent) spatial structures (e.g. area of multicellular population) change over time and across multiple levels of organization, which are not considered by existing model checking approaches. To address this limitation we have developed a novel approximate probabilistic multiscale spatio-temporal meta model checking methodology for verifying multilevel computational models relative to specifications describing the desired/expected system behaviour. The methodology is generic and supports computational models encoded using various high-level modelling formalisms because it is defined relative to time series data and not the models used to generate it. In addition, the methodology can be automatically adapted to case study specific types of spatial structures and properties using the spatio-temporal meta model checking concept. To automate the computational model verification process we have implemented the model checking approach in the software tool Mule (http://mule.modelchecking.org). Its applicability is illustrated against four systems biology computational models previously published in the literature encoding the rat cardiovascular system dynamics, the uterine contractions of labour

  5. Electrochemical migration technique to accelerate ageing of cementitious materials

    NASA Astrophysics Data System (ADS)

    Babaahmadi, A.; Tang, L.; Abbas, Z.

    2013-07-01

    Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW) takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen's micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

  6. Towards a Multiscale Approach to Cybersecurity Modeling

    SciTech Connect

    Hogan, Emilie A.; Hui, Peter SY; Choudhury, Sutanay; Halappanavar, Mahantesh; Oler, Kiri J.; Joslyn, Cliff A.

    2013-11-12

    We propose a multiscale approach to modeling cyber networks, with the goal of capturing a view of the network and overall situational awareness with respect to a few key properties--- connectivity, distance, and centrality--- for a system under an active attack. We focus on theoretical and algorithmic foundations of multiscale graphs, coming from an algorithmic perspective, with the goal of modeling cyber system defense as a specific use case scenario. We first define a notion of \\emph{multiscale} graphs, in contrast with their well-studied single-scale counterparts. We develop multiscale analogs of paths and distance metrics. As a simple, motivating example of a common metric, we present a multiscale analog of the all-pairs shortest-path problem, along with a multiscale analog of a well-known algorithm which solves it. From a cyber defense perspective, this metric might be used to model the distance from an attacker's position in the network to a sensitive machine. In addition, we investigate probabilistic models of connectivity. These models exploit the hierarchy to quantify the likelihood that sensitive targets might be reachable from compromised nodes. We believe that our novel multiscale approach to modeling cyber-physical systems will advance several aspects of cyber defense, specifically allowing for a more efficient and agile approach to defending these systems.

  7. Precision Closed-Loop Orbital Maneuvering System Design and Performance for the Magnetospheric Multi-Scale Mission (MMS) Formation

    NASA Technical Reports Server (NTRS)

    Chai, Dean; Queen, Steve; Placanica, Sam

    2015-01-01

    NASA's Magnetospheric Multi-Scale (MMS) mission successfully launched on March 13, 2015 (UTC) consists of four identically instrumented spin-stabilized observatories that function as a constellation to study magnetic reconnection in space. The need to maintain sufficiently accurate spatial and temporal formation resolution of the observatories must be balanced against the logistical constraints of executing overly-frequent maneuvers on a small fleet of spacecraft. These two considerations make for an extremely challenging maneuver design problem. This paper focuses on the design elements of a 6-DOF spacecraft attitude control and maneuvering system capable of delivering the high-precision adjustments required by the constellation designers---specifically, the design, implementation, and on-orbit performance of the closed-loop formation-class maneuvers that include initialization, maintenance, and re-sizing. The maneuvering control system flown on MMS utilizes a micro-gravity resolution accelerometer sampled at a high rate in order to achieve closed-loop velocity tracking of an inertial target with arc-minute directional and millimeter-per-second magnitude accuracy. This paper summarizes the techniques used for correcting bias drift, sensor-head offsets, and centripetal aliasing in the acceleration measurements. It also discusses the on-board pre-maneuver calibration and compensation algorithms as well as the implementation of the post-maneuver attitude adjustments.

  8. A Combined In Vitro Imaging and Multi-Scale Modeling System for Studying the Role of Cell Matrix Interactions in Cutaneous Wound Healing.

    PubMed

    De Jesus, Aribet M; Aghvami, Maziar; Sander, Edward A

    2016-01-01

    Many cell types remodel the extracellular matrix of the tissues they inhabit in response to a wide range of environmental stimuli, including mechanical cues. Such is the case in dermal wound healing, where fibroblast migrate into and remodel the provisional fibrin matrix in a complex manner that depends in part on the local mechanical environment and the evolving multi-scale mechanical interactions of the system. In this study, we report on the development of an image-based multi-scale mechanical model that predicts the short-term (24 hours), structural reorganization of a fibrin gel by fibroblasts. These predictive models are based on an in vitro experimental system where clusters of fibroblasts (i.e., explants) were spatially arranged into a triangular geometry onto the surface of fibrin gels that were subjected to either Fixed or Free in-plane mechanical constraints. Experimentally, regional differences in short-term structural remodeling and cell migration were observed for the two gel boundary conditions. A pilot experiment indicated that these small differences in the short-term remodeling of the fibrin gel translate into substantial differences in long-term (4 weeks) remodeling, particularly in terms of collagen production. The multi-scale models were able to predict some regional differences in remodeling and qualitatively similar reorganization patterns for the two boundary conditions. However, other aspects of the model, such as the magnitudes and rates of deformation of gel, did not match the experiments. These discrepancies between model and experiment provide fertile ground for challenging model assumptions and devising new experiments to enhance our understanding of how this multi-scale system functions. These efforts will ultimately improve the predictions of the remodeling process, particularly as it relates to dermal wound healing and the reduction of patient scarring. Such models could be used to recommend patient-specific mechanical

  9. A Combined In Vitro Imaging and Multi-Scale Modeling System for Studying the Role of Cell Matrix Interactions in Cutaneous Wound Healing

    PubMed Central

    2016-01-01

    Many cell types remodel the extracellular matrix of the tissues they inhabit in response to a wide range of environmental stimuli, including mechanical cues. Such is the case in dermal wound healing, where fibroblast migrate into and remodel the provisional fibrin matrix in a complex manner that depends in part on the local mechanical environment and the evolving multi-scale mechanical interactions of the system. In this study, we report on the development of an image-based multi-scale mechanical model that predicts the short-term (24 hours), structural reorganization of a fibrin gel by fibroblasts. These predictive models are based on an in vitro experimental system where clusters of fibroblasts (i.e., explants) were spatially arranged into a triangular geometry onto the surface of fibrin gels that were subjected to either Fixed or Free in-plane mechanical constraints. Experimentally, regional differences in short-term structural remodeling and cell migration were observed for the two gel boundary conditions. A pilot experiment indicated that these small differences in the short-term remodeling of the fibrin gel translate into substantial differences in long-term (4 weeks) remodeling, particularly in terms of collagen production. The multi-scale models were able to predict some regional differences in remodeling and qualitatively similar reorganization patterns for the two boundary conditions. However, other aspects of the model, such as the magnitudes and rates of deformation of gel, did not match the experiments. These discrepancies between model and experiment provide fertile ground for challenging model assumptions and devising new experiments to enhance our understanding of how this multi-scale system functions. These efforts will ultimately improve the predictions of the remodeling process, particularly as it relates to dermal wound healing and the reduction of patient scarring. Such models could be used to recommend patient-specific mechanical

  10. TECHNETIUM SORPTION BY CEMENTITIOUS MATERIALS UNDER REDUCING CONDITIONS

    SciTech Connect

    Kaplan, D.; Estes, S.; Arai, Y.; Powell, B.

    2012-01-31

    The objective of this study was to measure Tc sorption to cementitious materials under reducing conditions to simulate Saltstone Disposal Facility conditions. Earlier studies were conducted and the experimental conditions were found not to simulate those of the facility. Through a five month subcontract with Clemson University, sorption of {sup 99}Tc to four cementitious materials was examined within an anaerobic glovebag targeting a 0.1% H2(g)/ 99.9% N{sub 2}(g) atmosphere. Early experiments based on Tc sorption and Eh indicated that 0.1% H{sub 2}(g) (a reductant) was necessary to preclude experimental impacts from O{sub 2}(g) diffusion into the glovebag. Preliminary data to date (up to 56 days) indicates that sorption of {sup 99}Tc to cementitious materials increased with increasing slag content for simulated saltstone samples. This is consistent with the conceptual model that redox active sulfide groups within the reducing slag facilitate reduction of Tc(VII) to Tc(IV). These experiments differ from previous experiments where a 2% H{sub 2}(g) atmosphere was maintained (Kaplan et al., 2011 (SRNL-STI-2010-00668)). The impact of the 2% H{sub 2}(g) reducing atmosphere on this data was examined and determined to cause the reduction of Tc in experimental samples without slag. In the present ongoing study, after 56 days, Tc sorption by the 50-year old cement samples (no slag) was undetectable, whereas Tc sorption in the cementitious materials containing slag continues to increase with contact time (measured after 1, 4, 8, 19 and 56 days). Sorption was not consistent with spike concentrations and steady state has not been demonstrated after 56 days. The average conditional K{sub d} value for the Vault 2 cementitious material was 6,362 mL/g (17% slag), for the TR547 Saltstone (45% slag) the conditional K{sub d} was 1258 mL/g, and for TR545 (90% slag) the conditional K{sub d} was 12,112 mL/g. It is anticipated that additional samples will be collected until steady state

  11. Science-Grade Observing Systems as Process Observatories: Mapping and Understanding Nonlinearity and Multiscale Memory with Models and Observations

    NASA Astrophysics Data System (ADS)

    Barros, A. P.; Wilson, A. M.; Miller, D. K.; Tao, J.; Genereux, D. P.; Prat, O.; Petersen, W. A.; Brunsell, N. A.; Petters, M. D.; Duan, Y.

    2015-12-01

    Using the planet as a study domain and collecting observations over unprecedented ranges of spatial and temporal scales, NASA's EOS (Earth Observing System) program was an agent of transformational change in Earth Sciences over the last thirty years. The remarkable space-time organization and variability of atmospheric and terrestrial moist processes that emerged from the analysis of comprehensive satellite observations provided much impetus to expand the scope of land-atmosphere interaction studies in Hydrology and Hydrometeorology. Consequently, input and output terms in the mass and energy balance equations evolved from being treated as fluxes that can be used as boundary conditions, or forcing, to being viewed as dynamic processes of a coupled system interacting at multiple scales. Measurements of states or fluxes are most useful if together they map, reveal and/or constrain the underlying physical processes and their interactions. This can only be accomplished through an integrated observing system designed to capture the coupled physics, including nonlinear feedbacks and tipping points. Here, we first review and synthesize lessons learned from hydrometeorology studies in the Southern Appalachians and in the Southern Great Plains using both ground-based and satellite observations, physical models and data-assimilation systems. We will specifically focus on mapping and understanding nonlinearity and multiscale memory of rainfall-runoff processes in mountainous regions. It will be shown that beyond technical rigor, variety, quantity and duration of measurements, the utility of observing systems is determined by their interpretive value in the context of physical models to describe the linkages among different observations. Second, we propose a framework for designing science-grade and science-minded process-oriented integrated observing and modeling platforms for hydrometeorological studies.

  12. Multiscale reactive molecular dynamics

    NASA Astrophysics Data System (ADS)

    Knight, Chris; Lindberg, Gerrick E.; Voth, Gregory A.

    2012-12-01

    Many processes important to chemistry, materials science, and biology cannot be described without considering electronic and nuclear-level dynamics and their coupling to slower, cooperative motions of the system. These inherently multiscale problems require computationally efficient and accurate methods to converge statistical properties. In this paper, a method is presented that uses data directly from condensed phase ab initio simulations to develop reactive molecular dynamics models that do not require predefined empirical functions. Instead, the interactions used in the reactive model are expressed as linear combinations of interpolating functions that are optimized by using a linear least-squares algorithm. One notable benefit of the procedure outlined here is the capability to minimize the number of parameters requiring nonlinear optimization. The method presented can be generally applied to multiscale problems and is demonstrated by generating reactive models for the hydrated excess proton and hydroxide ion based directly on condensed phase ab initio molecular dynamics simulations. The resulting models faithfully reproduce the water-ion structural properties and diffusion constants from the ab initio simulations. Additionally, the free energy profiles for proton transfer, which is sensitive to the structural diffusion of both ions in water, are reproduced. The high fidelity of these models to ab initio simulations will permit accurate modeling of general chemical reactions in condensed phase systems with computational efficiency orders of magnitudes greater than currently possible with ab initio simulation methods, thus facilitating a proper statistical sampling of the coupling to slow, large-scale motions of the system.

  13. Multiscale reactive molecular dynamics

    PubMed Central

    Knight, Chris; Lindberg, Gerrick E.; Voth, Gregory A.

    2012-01-01

    Many processes important to chemistry, materials science, and biology cannot be described without considering electronic and nuclear-level dynamics and their coupling to slower, cooperative motions of the system. These inherently multiscale problems require computationally efficient and accurate methods to converge statistical properties. In this paper, a method is presented that uses data directly from condensed phase ab initio simulations to develop reactive molecular dynamics models that do not require predefined empirical functions. Instead, the interactions used in the reactive model are expressed as linear combinations of interpolating functions that are optimized by using a linear least-squares algorithm. One notable benefit of the procedure outlined here is the capability to minimize the number of parameters requiring nonlinear optimization. The method presented can be generally applied to multiscale problems and is demonstrated by generating reactive models for the hydrated excess proton and hydroxide ion based directly on condensed phase ab initio molecular dynamics simulations. The resulting models faithfully reproduce the water-ion structural properties and diffusion constants from the ab initio simulations. Additionally, the free energy profiles for proton transfer, which is sensitive to the structural diffusion of both ions in water, are reproduced. The high fidelity of these models to ab initio simulations will permit accurate modeling of general chemical reactions in condensed phase systems with computational efficiency orders of magnitudes greater than currently possible with ab initio simulation methods, thus facilitating a proper statistical sampling of the coupling to slow, large-scale motions of the system. PMID:23249062

  14. Developing Flexible, Integrated Hydrologic Modeling Systems for Multiscale Analysis in the Midwest and Great Lakes Region

    NASA Astrophysics Data System (ADS)

    Hamlet, A. F.; Chiu, C. M.; Sharma, A.; Byun, K.; Hanson, Z.

    2016-12-01

    Physically based hydrologic modeling of surface and groundwater resources that can be flexibly and efficiently applied to support water resources policy/planning/management decisions at a wide range of spatial and temporal scales are greatly needed in the Midwest, where stakeholder access to such tools is currently a fundamental barrier to basic climate change assessment and adaptation efforts, and also the co-production of useful products to support detailed decision making. Based on earlier pilot studies in the Pacific Northwest Region, we are currently assembling a suite of end-to-end tools and resources to support various kinds of water resources planning and management applications across the region. One of the key aspects of these integrated tools is that the user community can access gridded products at any point along the end-to-end chain of models, looking backwards in time about 100 years (1915-2015), and forwards in time about 85 years using CMIP5 climate model projections. The integrated model is composed of historical and projected future meteorological data based on station observations and statistical and dynamically downscaled climate model output respectively. These gridded meteorological data sets serve as forcing data for the macro-scale VIC hydrologic model implemented over the Midwest at 1/16 degree resolution. High-resolution climate model (4km WRF) output provides inputs for the analyses of urban impacts, hydrologic extremes, agricultural impacts, and impacts to the Great Lakes. Groundwater recharge estimated by the surface water model provides input data for fine-scale and macro-scale groundwater models needed for specific applications. To highlight the multi-scale use of the integrated models in support of co-production of scientific information for decision making, we briefly describe three current case studies addressing different spatial scales of analysis: 1) Effects of climate change on the water balance of the Great Lakes, 2) Future

  15. Multiscale modeling of the cardiovascular system: application to the study of pulmonary and coronary perfusions in the univentricular circulation.

    PubMed

    Laganà, Katia; Balossino, Rossella; Migliavacca, Francesco; Pennati, Giancarlo; Bove, Edward L; de Leval, Marc R; Dubini, Gabriele

    2005-05-01

    The objective of this study is to compare the coronary and pulmonary blood flow dynamics resulting from two configurations of systemic-to-pulmonary artery shunts currently utilized during the Norwood procedure: the central (CS) and modified Blalock Taussig (MBTS) shunts. A lumped parameter model of the neonatal cardiovascular circulation and detailed 3-D models of the shunt based on the finite volume method were constructed. Shunt sizes of 3, 3.5 and 4 mm were considered. A multiscale approach was adopted to prescribe appropriate and realistic boundary conditions for the 3-D models of the Norwood circulation. Results showed that the average shunt flow rate is higher for the CS option than for the MBTS and that pulmonary flow increases with shunt size for both options. Cardiac output is higher for the CS option for all shunt sizes. Flow distribution between the left and the right pulmonary arteries is not completely balanced, although for the CS option the discrepancy is low (50-51% of the pulmonary flow to the right lung) while for the MBTS it is more pronounced with larger shunt sizes (51-54% to the left lung). The CS option favors perfusion to the right lung while the MBTS favors the left. In the CS option, a smaller percentage of aortic flow is distributed to the coronary circulation, while that percentage rises for the MBTS. These findings may have important implications for coronary blood flow and ventricular function.

  16. Modeling the effects of light and sucrose on in vitro propagated plants: a multiscale system analysis using artificial intelligence technology.

    PubMed

    Gago, Jorge; Martínez-Núñez, Lourdes; Landín, Mariana; Flexas, Jaume; Gallego, Pedro P

    2014-01-01

    Plant acclimation is a highly complex process, which cannot be fully understood by analysis at any one specific level (i.e. subcellular, cellular or whole plant scale). Various soft-computing techniques, such as neural networks or fuzzy logic, were designed to analyze complex multivariate data sets and might be used to model large such multiscale data sets in plant biology. In this study we assessed the effectiveness of applying neuro-fuzzy logic to modeling the effects of light intensities and sucrose content/concentration in the in vitro culture of kiwifruit on plant acclimation, by modeling multivariate data from 14 parameters at different biological scales of organization. The model provides insights through application of 14 sets of straightforward rules and indicates that plants with lower stomatal aperture areas and higher photoinhibition and photoprotective status score best for acclimation. The model suggests the best condition for obtaining higher quality acclimatized plantlets is the combination of 2.3% sucrose and photonflux of 122-130 µmol m(-2) s(-1). Our results demonstrate that artificial intelligence models are not only successful in identifying complex non-linear interactions among variables, by integrating large-scale data sets from different levels of biological organization in a holistic plant systems-biology approach, but can also be used successfully for inferring new results without further experimental work.

  17. Modeling the Effects of Light and Sucrose on In Vitro Propagated Plants: A Multiscale System Analysis Using Artificial Intelligence Technology

    PubMed Central

    Gago, Jorge; Martínez-Núñez, Lourdes; Landín, Mariana; Flexas, Jaume; Gallego, Pedro P.

    2014-01-01

    Background Plant acclimation is a highly complex process, which cannot be fully understood by analysis at any one specific level (i.e. subcellular, cellular or whole plant scale). Various soft-computing techniques, such as neural networks or fuzzy logic, were designed to analyze complex multivariate data sets and might be used to model large such multiscale data sets in plant biology. Methodology and Principal Findings In this study we assessed the effectiveness of applying neuro-fuzzy logic to modeling the effects of light intensities and sucrose content/concentration in the in vitro culture of kiwifruit on plant acclimation, by modeling multivariate data from 14 parameters at different biological scales of organization. The model provides insights through application of 14 sets of straightforward rules and indicates that plants with lower stomatal aperture areas and higher photoinhibition and photoprotective status score best for acclimation. The model suggests the best condition for obtaining higher quality acclimatized plantlets is the combination of 2.3% sucrose and photonflux of 122–130 µmol m−2 s−1. Conclusions Our results demonstrate that artificial intelligence models are not only successful in identifying complex non-linear interactions among variables, by integrating large-scale data sets from different levels of biological organization in a holistic plant systems-biology approach, but can also be used successfully for inferring new results without further experimental work. PMID:24465829

  18. An in silico case study of idiopathic dilated cardiomyopathy via a multi-scale model of the cardiovascular system.

    PubMed

    Bhattacharya-Ghosh, Benjamin; Bozkurt, Selim; Rutten, Marcel C M; van de Vosse, Frans N; Díaz-Zuccarini, Vanessa

    2014-10-01

    Mathematical modelling has been used to comprehend the pathology and the assessment of different treatment techniques such as heart failure and left ventricular assist device therapy in the cardiovascular field. In this study, an in-silico model of the heart is developed to understand the effects of idiopathic dilated cardiomyopathy (IDC) as a pathological scenario, with mechanisms described at the cellular, protein and organ levels. This model includes the right and left atria and ventricles, as well as the systemic and pulmonary arteries and veins. First, a multi-scale model of the whole heart is simulated for healthy conditions. Subsequently, the model is modified at its microscopic and macroscopic spatial scale to obtain the characteristics of IDC. The extracellular calcium concentration, the binding affinity of calcium binding proteins and the maximum and minimum elastances have been identified as key parameters across all relevant scales. The modified parameters cause a change in (a) intracellular calcium concentration characterising cellular properties, such as calcium channel currents or the action potential, (b) the proteins being involved in the sliding filament mechanism and the proportion of the attached crossbridges at the protein level, as well as (c) the pressure and volume values at the organ level. This model allows to obtain insight and understanding of the effects of the treatment techniques, from a physiological and biological point of view. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Development of high-resolution multi-scale modelling system for simulation of coastal-fluvial urban flooding

    NASA Astrophysics Data System (ADS)

    Comer, Joanne; Indiana Olbert, Agnieszka; Nash, Stephen; Hartnett, Michael

    2017-02-01

    Urban developments in coastal zones are often exposed to natural hazards such as flooding. In this research, a state-of-the-art, multi-scale nested flood (MSN_Flood) model is applied to simulate complex coastal-fluvial urban flooding due to combined effects of tides, surges and river discharges. Cork city on Ireland's southwest coast is a study case. The flood modelling system comprises a cascade of four dynamically linked models that resolve the hydrodynamics of Cork Harbour and/or its sub-region at four scales: 90, 30, 6 and 2 m. Results demonstrate that the internalization of the nested boundary through the use of ghost cells combined with a tailored adaptive interpolation technique creates a highly dynamic moving boundary that permits flooding and drying of the nested boundary. This novel feature of MSN_Flood provides a high degree of choice regarding the location of the boundaries to the nested domain and therefore flexibility in model application. The nested MSN_Flood model through dynamic downscaling facilitates significant improvements in accuracy of model output without incurring the computational expense of high spatial resolution over the entire model domain. The urban flood model provides full characteristics of water levels and flow regimes necessary for flood hazard identification and flood risk assessment.

  20. An effective signal separation and extraction method using multi-scale wavelet decomposition for phase-sensitive OTDR system

    NASA Astrophysics Data System (ADS)

    Wu, Huijuan; Li, Xiaoyu; Li, Hanyu; Wu, Yu; Gong, Yuan; Rao, Yunjiang

    2013-10-01

    Phase-sensitive Optical-Time-Domain Reflectometry (OTDR) system is a typical distributed fiber-optic sensing technology to detect and locate multiple dynamic disturbances from the outside, which provides a cost-effective and highly sensitive solution especially for monitoring long or ultra-long perimeters. However, the system is liable to be interfered by laser frequency drifts and environmental noises due to its phase sensitivity. The fluctuant and time-varying backgrounds severely obscure real intrusion signals, which always cause bad detection results or high Nuisance Alarm Rates (NARs). In this paper, an effective signal separation method is proposed to extract true intrusion information from the complicated noisy backgrounds of phase-sensitive OTDR system. The sensing signal in the time-domain at each spatial point is obtained by accumulating the changing trails at different moments. Multi-scale wavelet decomposition is employed on the temporal signal to get the detailed components at different scales. By selectively recombining the scale components, it can easily extract the real intrusion signal, and separate the fluctuant frequency-drift induced phase noises, and the time-varying sound or other interferences caused by the air movements, which are respectively located at different time-frequency components. Moreover, the experimental results show that the event type could be divided and discerned from the time-frequency energy distribution at different scale. Thus nuisance and false alarms in practical applications of phase-sensitive OTDR system can be decreased significantly by this way of signal separation and extraction. This technique provides a useful solution for the intrusion detection and identification of the phase-sensitive OTDR in complicated environments, and paves the way for many important applications such as long perimeter security, oil or gas pipe safety monitoring, large-scale structure health detection and fault diagnosis and so on.

  1. A Computational Systems Biology Software Platform for Multiscale Modeling and Simulation: Integrating Whole-Body Physiology, Disease Biology, and Molecular Reaction Networks

    PubMed Central

    Eissing, Thomas; Kuepfer, Lars; Becker, Corina; Block, Michael; Coboeken, Katrin; Gaub, Thomas; Goerlitz, Linus; Jaeger, Juergen; Loosen, Roland; Ludewig, Bernd; Meyer, Michaela; Niederalt, Christoph; Sevestre, Michael; Siegmund, Hans-Ulrich; Solodenko, Juri; Thelen, Kirstin; Telle, Ulrich; Weiss, Wolfgang; Wendl, Thomas; Willmann, Stefan; Lippert, Joerg

    2011-01-01

    Today, in silico studies and trial simulations already complement experimental approaches in pharmaceutical R&D and have become indispensable tools for decision making and communication with regulatory agencies. While biology is multiscale by nature, project work, and software tools usually focus on isolated aspects of drug action, such as pharmacokinetics at the organism scale or pharmacodynamic interaction on the molecular level. We present a modeling and simulation software platform consisting of PK-Sim® and MoBi® capable of building and simulating models that integrate across biological scales. A prototypical multiscale model for the progression of a pancreatic tumor and its response to pharmacotherapy is constructed and virtual patients are treated with a prodrug activated by hepatic metabolization. Tumor growth is driven by signal transduction leading to cell cycle transition and proliferation. Free tumor concentrations of the active metabolite inhibit Raf kinase in the signaling cascade and thereby cell cycle progression. In a virtual clinical study, the individual therapeutic outcome of the chemotherapeutic intervention is simulated for a large population with heterogeneous genomic background. Thereby, the platform allows efficient model building and integration of biological knowledge and prior data from all biological scales. Experimental in vitro model systems can be linked with observations in animal experiments and clinical trials. The interplay between patients, diseases, and drugs and topics with high clinical relevance such as the role of pharmacogenomics, drug–drug, or drug–metabolite interactions can be addressed using this mechanistic, insight driven multiscale modeling approach. PMID:21483730

  2. Towards systems biology of the gravity response of higher plants -multiscale analysis of Arabidopsis thaliana root growth

    NASA Astrophysics Data System (ADS)

    Palme, Klaus; Aubry, D.; Bensch, M.; Schmidt, T.; Ronneberger, O.; Neu, C.; Li, X.; Wang, H.; Santos, F.; Wang, B.; Paponov, I.; Ditengou, F. A.; Teale, W. T.; Volkmann, D.; Baluska, F.; Nonis, A.; Trevisan, S.; Ruperti, B.; Dovzhenko, A.

    Gravity plays a fundamental role in plant growth and development. Up to now, little is known about the molecular organisation of the signal transduction cascades and networks which co-ordinate gravity perception and response. By using an integrated systems biological approach, a systems analysis of gravity perception and the subsequent tightly-regulated growth response is planned in the model plant Arabidopsis thaliana. This approach will address questions such as: (i) what are the components of gravity signal transduction pathways? (ii) what are the dynamics of these components? (iii) what is their spatio-temporal regulation in different tis-sues? Using Arabidopsis thaliana as a model-we use root growth to obtain insights in the gravity response. New techniques enable identification of the individual genes affected by grav-ity and further integration of transcriptomics and proteomics data into interaction networks and cell communication events that operate during gravitropic curvature. Using systematic multiscale analysis we have identified regulatory networks consisting of transcription factors, the protein degradation machinery, vesicle trafficking and cellular signalling during the gravire-sponse. We developed approach allowing to incorporate key features of the root system across all relevant spatial and temporal scales to describe gene-expression patterns and correlate them with individual gene and protein functions. Combination of high-resolution microscopy and novel computational tools resulted in development of the root 3D model in which quantitative descriptions of cellular network properties and of multicellular interactions important in root growth and gravitropism can be integrated for the first time.

  3. The multiscale coarse-graining method. X. Improved algorithms for constructing coarse-grained potentials for molecular systems.

    PubMed

    Das, Avisek; Lu, Lanyuan; Andersen, Hans C; Voth, Gregory A

    2012-05-21

    The multiscale coarse-graining (MS-CG) method uses simulation data for an atomistic model of a system to construct a coarse-grained (CG) potential for a coarse-grained model of the system. The CG potential is a variational approximation for the true potential of mean force of the degrees of freedom retained in the CG model. The variational calculation uses information about the atomistic positions and forces in the simulation data. In principle, the resulting MS-CG potential will be an accurate representation of the true CG potential if the basis set for the variational calculation is complete enough and the canonical distribution of atomistic states is well sampled by the data set. In practice, atomistic configurations that have very high potential energy are not sampled. As a result there usually is a region of CG configuration space that is not sampled and about which the data set contains no information regarding the gradient of the true potential. The MS-CG potential obtained from a variational calculation will not necessarily be accurate in this unsampled region. A priori considerations make it clear that the true CG potential of mean force must be very large and positive in that region. To obtain an MS-CG potential whose behavior in the sampled region is determined by the atomistic data set, and whose behavior in the unsampled region is large and positive, it is necessary to intervene in the variational calculation in some way. In this paper, we discuss and compare two such methods of intervention, which have been used in previous MS-CG calculations for dealing with nonbonded interactions. For the test systems studied, the two methods give similar results and yield MS-CG potentials that are limited in accuracy only by the incompleteness of the basis set and the statistical error of associated with the set of atomistic configurations used. The use of such methods is important for obtaining accurate CG potentials.

  4. On multiscale entropy analysis for physiological data

    NASA Astrophysics Data System (ADS)

    Thuraisingham, Ranjit A.; Gottwald, Georg A.

    2006-07-01

    We perform an analysis of cardiac data using multiscale entropy as proposed in Costa et al. [Multiscale entropy analysis of complex physiological time series, Phys. Rev. Lett. 89 (2002) 068102]. We reproduce the signatures of the multiscale entropy for the three cases of young healthy hearts, atrial fibrillation and congestive heart failure. We show that one has to be cautious how to interpret these signatures in terms of the underlying dynamics. In particular, we show that different dynamical systems can exhibit the same signatures depending on the sampling time, and that similar systems may have different signatures depending on the time scales involved. Besides the total amount of data we identify the sampling time, the correlation time and the period of possible nonlinear oscillations as important time scales which have to be involved in a detailed analysis of the signatures of multiscale entropies. We illustrate our ideas with the Lorenz equation as a simple deterministic chaotic system.

  5. Designing a multiscale experimental sampling system for quantification of stream-aquifer water exchanges - the Orgeval basin case study (France)

    NASA Astrophysics Data System (ADS)

    Mouhri, A.; Flipo, N.; Rejiba, F.; Durand, V.; Tallec, G.; Kurtulus, B.

    2011-12-01

    With an area of 104 km2, the Orgeval experimental basin is located 70 km east from Paris. It drains a multi-layer aquifer system, which is composed of two main geological formations: the Oligocene and the Eocene. These two aquifer units are separated by a clayey aquitard. Most of the basin is covered with table-land loess about 2-5m in thickness. These unconsolidated deposits are essentially composed of sand and loam lenses of low permeability. The aim of this work is to understand the water exchanges between the streams and the aquifers at both the basin and the hyporheic zone scales. Some preliminary head observations lead to assume that the downstream part of the river is flowing into the aquifer, contrary to the upstream part where the exchange relationships seem more classical. To investigate this issue, we focus in this presentation on the design of a multiscale experimental sampling system. First of all the basin scale was investigated. The underground structure of the basin was defined using the 1/50 000 geological map coupled with extensive geophysical investigations. Those surveys, which include extensive TDEM (Time Domain ElectroMagnetic) soundings and ERT (Electrical Resistivity Tomography) measurements, have been performed in order to improve the description of the near surface geology associated with likely connections between the stream network and the two different aquifers. The geophysical investigations validate the fact that the land loess are connected to the Oligocene limestones to compose the upper aquifer unit of the basin, so called Oligocene. Based on three snapshot campaigns where piezometric head were measured in around 50 wells distributed in the basin, piezometric head maps representative of low, medium and high water were interpolated. The sensitivity of these maps to the interpolation technique (ANFIS or Kriging using different digital elevation models as an external drift) was also investigated. This step allowed for defining the

  6. Simulating Nationwide Pandemics: Applying the Multi-scale Epidemiologic Simulation and Analysis System to Human Infectious Diseases

    SciTech Connect

    Dombroski, M; Melius, C; Edmunds, T; Banks, L E; Bates, T; Wheeler, R

    2008-09-24

    This study uses the Multi-scale Epidemiologic Simulation and Analysis (MESA) system developed for foreign animal diseases to assess consequences of nationwide human infectious disease outbreaks. A literature review identified the state of the art in both small-scale regional models and large-scale nationwide models and characterized key aspects of a nationwide epidemiological model. The MESA system offers computational advantages over existing epidemiological models and enables a broader array of stochastic analyses of model runs to be conducted because of those computational advantages. However, it has only been demonstrated on foreign animal diseases. This paper applied the MESA modeling methodology to human epidemiology. The methodology divided 2000 US Census data at the census tract level into school-bound children, work-bound workers, elderly, and stay at home individuals. The model simulated mixing among these groups by incorporating schools, workplaces, households, and long-distance travel via airports. A baseline scenario with fixed input parameters was run for a nationwide influenza outbreak using relatively simple social distancing countermeasures. Analysis from the baseline scenario showed one of three possible results: (1) the outbreak burned itself out before it had a chance to spread regionally, (2) the outbreak spread regionally and lasted a relatively long time, although constrained geography enabled it to eventually be contained without affecting a disproportionately large number of people, or (3) the outbreak spread through air travel and lasted a long time with unconstrained geography, becoming a nationwide pandemic. These results are consistent with empirical influenza outbreak data. The results showed that simply scaling up a regional small-scale model is unlikely to account for all the complex variables and their interactions involved in a nationwide outbreak. There are several limitations of the methodology that should be explored in future

  7. CEMENTITIOUS BARRIERS PARTNERSHIP FY13 MID-YEAR REPORT

    SciTech Connect

    Burns, H.; Flach, G.; Langton, C.; KOSSON, D.; BROWN, K.; SAMSON, E.; MEEUSSEN, J.; SLOOT, H.; GARBOCZI, E.

    2013-05-01

    In FY2013, the Cementitious Barriers Partnership (CBP) is continuing in its effort to develop and enhance software tools demonstrating tangible progress toward fulfilling the objective of developing a set of tools to improve understanding and prediction of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. In FY2012, the CBP released the initial inhouse “Beta-version” of the CBP Software Toolbox, a suite of software for simulating reactive transport in cementitious materials and important degradation phenomena. The current primary software components are LeachXS/ORCHESTRA, STADIUM, and a GoldSim interface for probabilistic analysis of selected degradation scenarios. THAMES is a planned future CBP Toolbox component (FY13/14) focused on simulation of the microstructure of cementitious materials and calculation of resultant hydraulic and constituent mass transfer parameters needed in modeling. This past November, the CBP Software Toolbox Version 1.0 was released that supports analysis of external sulfate attack (including damage mechanics), carbonation, and primary constituent leaching. The LeachXS component embodies an extensive material property measurements database along with chemical speciation and reactive mass transport simulation cases with emphasis on leaching of major, trace and radionuclide constituents from cementitious materials used in DOE facilities, such as Saltstone (Savannah River) and Cast Stone (Hanford), tank closure grouts, and barrier concretes. STADIUM focuses on the physical and structural service life of materials and components based on chemical speciation and reactive mass transport of major cement constituents and aggressive species (e.g., chloride, sulfate, etc.). The CBP issued numerous reports and other documentation that accompanied the “Version 1.0” release including a CBP Software Toolbox User Guide and Installation Guide. These documents, as well as, the

  8. Degradation of cementitious materials associated with salstone disposal units

    SciTech Connect

    Flach, G. P.; Smith, F. G.

    2014-09-01

    The Saltstone facilities at the DOE Savannah River Site (SRS) stabilize and dispose of low-level radioactive salt solution originating from liquid waste storage tanks at the site. The Saltstone Production Facility (SPF) receives treated salt solution and mixes the aqueous waste with dry cement, blast furnace slag, and fly ash to form a grout slurry which is mechanically pumped into concrete disposal cells that compose the Saltstone Disposal Facility (SDF). The solidified grout is termed “saltstone”. Cementitious materials play a prominent role in the design and long-term performance of the SDF. The saltstone grout exhibits low permeability and diffusivity, and thus represents a physical barrier to waste release. The waste form is also reducing, which creates a chemical barrier to waste release for certain key radionuclides, notably Tc-99. Similarly, the concrete shell of a saltstone disposal unit (SDU) represents an additional physical and chemical barrier to radionuclide release to the environment. Together the waste form and the SDU compose a robust containment structure at the time of facility closure. However, the physical and chemical state of cementitious materials will evolve over time through a variety of phenomena, leading to degraded barrier performance over Performance Assessment (PA) timescales of thousands to tens of thousands of years. Previous studies of cementitious material degradation in the context of low-level waste disposal have identified sulfate attack, carbonation influenced steel corrosion, and decalcification (primary constituent leaching) as the primary chemical degradation phenomena of most relevance to SRS exposure conditions. In this study, degradation time scales for each of these three degradation phenomena are estimated for saltstone and concrete associated with each SDU type under conservative, nominal, and best estimate assumptions.

  9. Cementitious Barriers Partnership - FY2015 End-Year Report

    SciTech Connect

    Burns, H. H.; Flach, G. P.; Langton, C. A.; Smith, F. G.; Kosson, D. S.; Brown, K. G.; Samson, E.; Meeussen, J. C. L.; Seignette, Paul; van der Sloot, H. A.

    2015-09-17

    The DOE-EM Office of Tank Waste Management Cementitious Barriers Partnership (CBP) is chartered with providing the technical basis for implementing cement-based waste forms and radioactive waste containment structures for long-term disposal. Therefore, the CBP ultimate purpose is to support progress in final treatment and disposal of legacy waste and closure of High-Level Waste (HLW) tanks in the DOE complex. This status report highlights the CBP 2015 Software and Experimental Program efforts and accomplishments that support DOE needs in environmental cleanup and waste disposal. DOE needs in this area include: Long-term performance predictions to provide credibility (i.e., a defensible technical basis) for regulator and DOE review and approvals, Facility flow sheet development/enhancements, and Conceptual designs for new disposal facilities. In 2015, the CBP developed a beta release of the CBP Software Toolbox – “Version 3.0”, which includes new STADIUM carbonation and damage models, a new SRNL module for estimating hydraulic properties and flow in fractured and intact cementitious materials, and a new LeachXS/ORCHESTRA (LXO) oxidation module. In addition, the STADIUM sulfate attack and chloride models have been improved as well as the LXO modules for sulfate attack, carbonation, constituent leaching, and percolation with radial diffusion (for leaching and transport in cracked cementitious materials). These STADIUM and LXO models are applicable to and can be used by both DOE and the Nuclear Regulatory Commission (NRC) end-users for service life prediction and long-term leaching evaluations of radioactive waste containment structures across the DOE complex.

  10. Transport properties of damaged materials. Cementitious barriers partnership

    SciTech Connect

    Langton, C.

    2014-11-01

    The objective of the Cementitious Barriers Partnership (CBP) project is to develop tools to improve understanding and prediction of the long-term structural, hydraulic, and chemical performance of cementitious barriers used in low-level waste storage applications. One key concern for the long-term durability of concrete is the degradation of the cementitious matrix, which occurs as a result of aggressive chemical species entering the material or leaching out in the environment, depending on the exposure conditions. The objective of the experimental study described in this report is to provide experimental data relating damage in cementitious materials to changes in transport properties, which can eventually be used to support predictive model development. In order to get results within a reasonable timeframe and to induce as much as possible uniform damage level in materials, concrete samples were exposed to freezing and thawing (F/T) cycles. The methodology consisted in exposing samples to F/T cycles and monitoring damage level with ultrasonic pulse velocity measurements. Upon reaching pre-selected damage levels, samples were tested to evaluate changes in transport properties. Material selection for the study was motivated by the need to get results rapidly, in order to assess the relevance of the methodology. Consequently, samples already available at SIMCO from past studies were used. They consisted in three different concrete mixtures cured for five years in wet conditions. The mixtures had water-to-cement ratios of 0.5, 0.65 and 0.75 and were prepared with ASTM Type I cement only. The results showed that porosity is not a good indicator for damage caused by the formation of microcracks. Some materials exhibited little variations in porosity even for high damage levels. On the other hand, significant variations in tortuosity were measured in all materials. This implies that damage caused by internal pressure does not necessarily create additional pore space in

  11. Multiscale modeling methods in biomechanics.

    PubMed

    Bhattacharya, Pinaki; Viceconti, Marco

    2017-01-19

    More and more frequently, computational biomechanics deals with problems where the portion of physical reality to be modeled spans over such a large range of spatial and temporal dimensions, that it is impossible to represent it as a single space-time continuum. We are forced to consider multiple space-time continua, each representing the phenomenon of interest at a characteristic space-time scale. Multiscale models describe a complex process across multiple scales, and account for how quantities transform as we move from one scale to another. This review offers a set of definitions for this emerging field, and provides a brief summary of the most recent developments on multiscale modeling in biomechanics. Of all possible perspectives, we chose that of the modeling intent, which vastly affect the nature and the structure of each research activity. To the purpose we organized all papers reviewed in three categories: 'causal confirmation,' where multiscale models are used as materializations of the causation theories; 'predictive accuracy,' where multiscale modeling is aimed to improve the predictive accuracy; and 'determination of effect,' where multiscale modeling is used to model how a change at one scale manifests in an effect at another radically different space-time scale. Consistent with how the volume of computational biomechanics research is distributed across application targets, we extensively reviewed papers targeting the musculoskeletal and the cardiovascular systems, and covered only a few exemplary papers targeting other organ systems. The review shows a research subdomain still in its infancy, where causal confirmation papers remain the most common. For further resources related to this article, please visit the WIREs website.

  12. Numerical modeling of polyurea coated cementitious materials for flexure and impact loads

    NASA Astrophysics Data System (ADS)

    Pothula, Naga Deepika

    The research focuses on predicting the mechanical properties of various cementitious based materials coated with polyurea using the finite element program ABAQUS. To determine the effect of the polyurea coated systems, simple finite element analyses are performed on the beam model for flexure and the concrete slab model for impact. The experimental results carried out by Hyungjoo Choi [1, 2] are used to validate the model and to study the effect of the coating conditions of polyurea (plain, top, bottom, both). The load-displacement curves are plotted. Results show that using polyurea coating increases of deflection and load at failure (ductility), ultimate strength and strain, of Poly (Vinyl Butyral) (PVB) and Poly (Vinyl Alcohol) (PVA) fiber reinforced specimens. The simulation response for various models matched the experimental results very closely. Impact models depict the stresses developed and show that applying polyurea coating on the bottom seems to produce the best results.

  13. Development of New Cementitious Caterials by Alkaline Activating Industrial by-Products

    NASA Astrophysics Data System (ADS)

    Fernández-Jimenez, A.; García-Lodeiro, I.; Palomo, A.

    2015-11-01

    The alkaline activation of aluminosiliceous industrial by-products such as blast furnace slag and fly ash is widely known to yield binders whose properties make them comparable to or even stronger and more durable than ordinary Portland cement. The present paper discusses activation fundamentals (such as the type and concentration of alkaline activator and curing conditions) as well as the structure of the cementitious gels formed (C-A-S-H, N-A-S-H). The durability and strength of these systems make these materials apt for use in many industrial applications, such as precast concrete elements (masonery blocks, railroad sleepers), protective coatings for materials with low fire ratings and lightweight elements.

  14. Magnetospheric Multiscale (MMS) Orbit

    NASA Image and Video Library

    This animation shows the orbits of Magnetospheric Multiscale (MMS) mission, a Solar-Terrestrial Probe mission comprising of four identically instrumented spacecraft that will study the Earth's magn...

  15. LINKING ETA MODEL WITH THE COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODELING SYSTEM: OZONE BOUNDARY CONDITIONS

    EPA Science Inventory

    A prototype surface ozone concentration forecasting model system for the Eastern U.S. has been developed. The model system is consisting of a regional meteorological and a regional air quality model. It demonstrated a strong prediction dependence on its ozone boundary conditions....

  16. LINKING ETA MODEL WITH THE COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODELING SYSTEM: OZONE BOUNDARY CONDITIONS

    EPA Science Inventory

    A prototype surface ozone concentration forecasting model system for the Eastern U.S. has been developed. The model system is consisting of a regional meteorological and a regional air quality model. It demonstrated a strong prediction dependence on its ozone boundary conditions....

  17. van der Waals dispersion power laws for cleavage, exfoliation, and stretching in multiscale, layered systems

    NASA Astrophysics Data System (ADS)

    Gould, Tim; Gray, Evan; Dobson, John F.

    2009-03-01

    Layered and nanotubular systems that are metallic or graphitic are known to exhibit unusual dispersive van der Waals (vdW) power laws under some circumstances. In this Brief Report we investigate the vdW power laws of bulk and finite layered systems and their interactions with other layered systems and atoms in the electromagnetically nonretarded case. The investigation reveals substantial difference between “cleavage” and “exfoliation” of graphite and metals where cleavage obeys a C2D-2 vdW power law while exfoliation obeys a C3log(D/D0)D-3 law for graphitics and a C5/2D-5/2 law for layered metals. This leads to questions of relevance in the interpretation of experimental results for these systems which have previously assumed more trivial differences. Furthermore we gather further insight into the effect of scale on the vdW power laws of systems that simultaneously exhibit macroscopic and nanoscopic dimensions. We show that, for metallic and graphitic layered systems, the known “unusual” power laws can be reduced to standard or near standard power laws when the effective scale of one or more dimension is changed. This allows better identification of the systems for which the commonly employed “sum of C6D-6 ” type vdW methods might be valid such as layered bulk to layered bulk and layered bulk to atom.

  18. Experimental Study on Cementitious Composites Embedded with Organic Microcapsules

    PubMed Central

    Wang, Xianfeng; Xing, Feng; Zhang, Ming; Han, Ningxu; Qian, Zhiwei

    2013-01-01

    The recovery behavior for strength and impermeability of cementitious composites embedded with organic microcapsules was investigated in this study. Mortar specimens were formed by mixing the organic microcapsules and a catalyst with cement and sand. The mechanical behaviors of flexural and compression strength were tested. The results showed that strength could increase by up to nine percent with the addition of a small amount of microcapsules and then decrease with an increasing amount of microcapsules. An orthogonal test for investigating the strength recovery rate was designed and implemented for bending and compression using the factors of water/cement ratio, amount of microcapsules, and preloading rate. It is shown that the amount of microcapsules plays a key role in the strength recovery rate. Chloride ion permeability tests were also carried out to investigate the recovery rate and healing effect. The initial damage was obtained by subjecting the specimens to compression. Both the recovery rate and the healing effect were nearly proportional to the amount of microcapsules. The obtained cementitious composites can be seen as self-healing owing to their recovery behavior for both strength and permeability. PMID:28788318

  19. Semiautomatic classification of cementitious materials using scanning electron microscope images

    NASA Astrophysics Data System (ADS)

    Drumetz, Lucas; Mura, Mauro Dalla; Meulenyzer, Samuel; Lombard, Sébastien; Chanussot, Jocelyn

    2015-11-01

    Segmentation and classification are prolific research topics in the image processing community. These topics have been increasingly used in the context of analysis of cementitious materials on images acquired with a scanning electron microscope. Indeed, there is a need to be able to detect and to quantify the materials present in a cement paste in order to follow the chemical reactions occurring in the material even days after the solidification. We propose a new approach for segmentation and classification of cementitious materials based on the denoising of the data with a block-matching three-dimensional (3-D) algorithm, binary partition tree (BPT) segmentation, support vector machines (SVM) classification, and interactivity with the user. The BPT provides a hierarchical representation of the spatial regions of the data, allowing a segmentation to be selected among the admissible partitions of the image. SVMs are used to obtain a classification map of the image. This approach combines state-of-the-art image processing tools with user interactivity to allow a better segmentation to be performed, or to help the classifier discriminate the classes better. We show that the proposed approach outperforms a previous method when applied to synthetic data and several real datasets coming from cement samples, both qualitatively with visual examination and quantitatively with the comparison of experimental results with theoretical ones.

  20. Experimental Study on Cementitious Composites Embedded with Organic Microcapsules.

    PubMed

    Wang, Xianfeng; Xing, Feng; Zhang, Ming; Han, Ningxu; Qian, Zhiwei

    2013-09-16

    The recovery behavior for strength and impermeability of cementitious composites embedded with organic microcapsules was investigated in this study. Mortar specimens were formed by mixing the organic microcapsules and a catalyst with cement and sand. The mechanical behaviors of flexural and compression strength were tested. The results showed that strength could increase by up to nine percent with the addition of a small amount of microcapsules and then decrease with an increasing amount of microcapsules. An orthogonal test for investigating the strength recovery rate was designed and implemented for bending and compression using the factors of water/cement ratio, amount of microcapsules, and preloading rate. It is shown that the amount of microcapsules plays a key role in the strength recovery rate. Chloride ion permeability tests were also carried out to investigate the recovery rate and healing effect. The initial damage was obtained by subjecting the specimens to compression. Both the recovery rate and the healing effect were nearly proportional to the amount of microcapsules. The obtained cementitious composites can be seen as self-healing owing to their recovery behavior for both strength and permeability.

  1. Non-equilibrium transitions in multiscale systems with a bifurcating slow manifold

    NASA Astrophysics Data System (ADS)

    Grafke, Tobias; Vanden-Eijnden, Eric

    2017-09-01

    Noise-induced transitions between metastable fixed points in systems evolving on multiple time scales are analyzed in situations where the time scale separation gives rise to a slow manifold with bifurcation. This analysis is performed within the realm of large deviation theory. It is shown that these non-equilibrium transitions make use of a reaction channel created by the bifurcation structure of the slow manifold, leading to vastly increased transition rates. Several examples are used to illustrate these findings, including an insect outbreak model, a system modeling phase separation in the presence of evaporation, and a system modeling transitions in active matter self-assembly. The last example involves a spatially extended system modeled by a stochastic partial differential equation.

  2. Multiscale modeling of proteins.

    PubMed

    Tozzini, Valentina

    2010-02-16

    The activity within a living cell is based on a complex network of interactions among biomolecules, exchanging information and energy through biochemical processes. These events occur on different scales, from the nano- to the macroscale, spanning about 10 orders of magnitude in the space domain and 15 orders of magnitude in the time domain. Consequently, many different modeling techniques, each proper for a particular time or space scale, are commonly used. In addition, a single process often spans more than a single time or space scale. Thus, the necessity arises for combining the modeling techniques in multiscale approaches. In this Account, I first review the different modeling methods for bio-systems, from quantum mechanics to the coarse-grained and continuum-like descriptions, passing through the atomistic force field simulations. Special attention is devoted to their combination in different possible multiscale approaches and to the questions and problems related to their coherent matching in the space and time domains. These aspects are often considered secondary, but in fact, they have primary relevance when the aim is the coherent and complete description of bioprocesses. Subsequently, applications are illustrated by means of two paradigmatic examples: (i) the green fluorescent protein (GFP) family and (ii) the proteins involved in the human immunodeficiency virus (HIV) replication cycle. The GFPs are currently one of the most frequently used markers for monitoring protein trafficking within living cells; nanobiotechnology and cell biology strongly rely on their use in fluorescence microscopy techniques. A detailed knowledge of the actions of the virus-specific enzymes of HIV (specifically HIV protease and integrase) is necessary to study novel therapeutic strategies against this disease. Thus, the insight accumulated over years of intense study is an excellent framework for this Account. The foremost relevance of these two biomolecular systems was

  3. Multiscale N = 2 SUSY field theories, integrable systems and their stringy /brane origin

    NASA Astrophysics Data System (ADS)

    Gorsky, A.; Gukov, S.; Mironov, A.

    1998-04-01

    We discuss supersymmetric Yang-Mills theories with multiple scales in the brane language. The issue concerns N = 2 SUSY gauge theories with massive fundamental matter including the UV finite case of nf = 2 nc, theories involving products of SU( n) gauge groups with bifundamental matter, and systems with several parameters similar to ΛQCD. We argue that the proper integrable systems are, accordingly, twisted XXX SL(2) spin chain, SL( p) magnets and degenerations of the spin Calogero system. The issue of symmetries underlying integrable systems is addressed. Relations with the monopole systems are specially discussed. Brane pictures behind all these integrable structures in the IIB and M-theory are suggested. We argue that degrees of freedom in integrable systems are related to KK excitations in M-theory or D-particles in the IIA string theory, which substitute the infinite number of instantons in the field theory. This implies the presence of more BPS states in the low-energy sector.

  4. Degradation Of Cementitious Materials Associated With Saltstone Disposal Units

    SciTech Connect

    Flach, G. P; Smith, F. G. III

    2013-03-19

    The Saltstone facilities at the DOE Savannah River Site (SRS) stabilize and dispose of low-level radioactive salt solution originating from liquid waste storage tanks at the site. The Saltstone Production Facility (SPF) receives treated salt solution and mixes the aqueous waste with dry cement, blast furnace slag, and fly ash to form a grout slurry which is mechanically pumped into concrete disposal cells that compose the Saltstone Disposal Facility (SDF). The solidified grout is termed “saltstone”. Cementitious materials play a prominent role in the design and long-term performance of the SDF. The saltstone grout exhibits low permeability and diffusivity, and thus represents a physical barrier to waste release. The waste form is also reducing, which creates a chemical barrier to waste release for certain key radionuclides, notably Tc-99. Similarly, the concrete shell of an SDF disposal unit (SDU) represents an additional physical and chemical barrier to radionuclide release to the environment. Together the waste form and the SDU compose a robust containment structure at the time of facility closure. However, the physical and chemical state of cementitious materials will evolve over time through a variety of phenomena, leading to degraded barrier performance over Performance Assessment (PA) timescales of thousands to tens of thousands of years. Previous studies of cementitious material degradation in the context of low-level waste disposal have identified sulfate attack, carbonation influenced steel corrosion, and decalcification (primary constituent leaching) as the primary chemical degradation phenomena of most relevance to SRS exposure conditions. In this study, degradation time scales for each of these three degradation phenomena are estimated for saltstone and concrete associated with each SDU type under conservative, nominal, and best estimate assumptions. The nominal value (NV) is an intermediate result that is more probable than the conservative

  5. Technetium Sorption By Cementitious Materials Under Reducing Conditions

    SciTech Connect

    Kaplan, Daniel I.; Estes, Shanna L.; Arai, Yuji; Powell, Brian A.

    2013-07-18

    The objective of this study was to measure Tc sorption to cementitious materials under reducing conditions to simulate Saltstone Disposal Facility conditions. Earlier studies were conducted and the experimental conditions were found not to simulate those of the facility. Through a five month subcontract with Clemson University, sorption of {sup 99}Tc to four cementitious materials was examined within an anaerobic glovebag targeting a 0.1% H{sub 2}(g)/ 99.9% N{sub 2}(g) atmosphere. Early experiments based on Tc sorption and Eh indicated that 0.1% H{sub 2}(g) (a reductant) was necessary to preclude experimental impacts from O{sub 2}(g) diffusion into the glovebag. Preliminary data to date (up to 56 days) indicates that sorption of {sup 99}Tc to cementitious materials increased with increasing slag content for simulated saltstone samples. This is consistent with the conceptual model that redox active sulfide groups within the reducing slag facilitate reduction of Tc(VII) to Tc(IV). These experiments differ from previous experiments where a 2% H{sub 2}(g) atmosphere was maintained (Kaplan et al., 2011 (SRNL-STI-2010-00668)). The impact of the 2% H{sub 2}(g) reducing atmosphere on this data was examined and determined to cause the reduction of Tc in experimental samples without slag. In the present ongoing study, after 56 days, Tc sorption by the 50-year old cement samples (no slag) was undetectable, whereas Tc sorption in the cementitious materials containing slag continues to increase with contact time (measured after 1, 4, 8, 19 and 56 days). Sorption was not consistent with spike concentrations and steady state has not been demonstrated after 56 days. The average conditional K{sub d} value for the Vault 2 cementitious material was 873 mL/g (17% slag), for the TR547 Saltstone (45% slag) the conditional K{sub d} was 168 mL/g, and for TR545 (90% slag) the conditional K{sub d} was 1,619 mL/g. It is anticipated that additional samples will be collected until steady state

  6. Soil Moisture Processes in the Near Surface Unsaturated Zone: Experimental Investigations in Multi-scale Test Systems

    NASA Astrophysics Data System (ADS)

    Illangasekare, T. H.; Sakaki, T.; Smits, K. M.; Limsuwat, A.; Terrés-Nícoli, J. M.

    2008-12-01

    scale test systems together with instrumentation and measuring techniques. The features and capabilities of a new coupled porous media/climate wind tunnel test system that allows for the study of near surface unsaturated soil moisture conditions under climate boundary conditions will also be presented with the goal of exploring opportunities to use such a facility to study some of the multi-scale problems in the near surface unsaturated zone.

  7. Strategies and Tactics in Multiscale Modeling of Cell-to-Organ Systems

    PubMed Central

    Bassingthwaighte, James B.; Chizeck, Howard Jay; Atlas, Les E.

    2010-01-01

    Modeling is essential to integrating knowledge of human physiology. Comprehensive self-consistent descriptions expressed in quantitative mathematical form define working hypotheses in testable and reproducible form, and though such models are always “wrong” in the sense of being incomplete or partly incorrect, they provide a means of understanding a system and improving that understanding. Physiological systems, and models of them, encompass different levels of complexity. The lowest levels concern gene signaling and the regulation of transcription and translation, then biophysical and biochemical events at the protein level, and extend through the levels of cells, tissues and organs all the way to descriptions of integrated systems behavior. The highest levels of organization represent the dynamically varying interactions of billions of cells. Models of such systems are necessarily simplified to minimize computation and to emphasize the key factors defining system behavior; different model forms are thus often used to represent a system in different ways. Each simplification of lower level complicated function reduces the range of accurate operability at the higher level model, reducing robustness, the ability to respond correctly to dynamic changes in conditions. When conditions change so that the complexity reduction has resulted in the solution departing from the range of validity, detecting the deviation is critical, and requires special methods to enforce adapting the model formulation to alternative reduced-form modules or decomposing the reduced-form aggregates to the more detailed lower level modules to maintain appropriate behavior. The processes of error recognition, and of mapping between different levels of model complexity and shifting the levels of complexity of models in response to changing conditions, are essential for adaptive modeling and computer simulation of large-scale systems in reasonable time. PMID:20463841

  8. Strategies and Tactics in Multiscale Modeling of Cell-to-Organ Systems.

    PubMed

    Bassingthwaighte, James B; Chizeck, Howard Jay; Atlas, Les E

    2006-04-01

    Modeling is essential to integrating knowledge of human physiology. Comprehensive self-consistent descriptions expressed in quantitative mathematical form define working hypotheses in testable and reproducible form, and though such models are always "wrong" in the sense of being incomplete or partly incorrect, they provide a means of understanding a system and improving that understanding. Physiological systems, and models of them, encompass different levels of complexity. The lowest levels concern gene signaling and the regulation of transcription and translation, then biophysical and biochemical events at the protein level, and extend through the levels of cells, tissues and organs all the way to descriptions of integrated systems behavior. The highest levels of organization represent the dynamically varying interactions of billions of cells. Models of such systems are necessarily simplified to minimize computation and to emphasize the key factors defining system behavior; different model forms are thus often used to represent a system in different ways. Each simplification of lower level complicated function reduces the range of accurate operability at the higher level model, reducing robustness, the ability to respond correctly to dynamic changes in conditions. When conditions change so that the complexity reduction has resulted in the solution departing from the range of validity, detecting the deviation is critical, and requires special methods to enforce adapting the model formulation to alternative reduced-form modules or decomposing the reduced-form aggregates to the more detailed lower level modules to maintain appropriate behavior. The processes of error recognition, and of mapping between different levels of model complexity and shifting the levels of complexity of models in response to changing conditions, are essential for adaptive modeling and computer simulation of large-scale systems in reasonable time.

  9. Adaptive systems for processing of high-dimensional and multi-scale data: Application to forecasting of geomagnetic substorms and financial time series.

    NASA Astrophysics Data System (ADS)

    Gavrishchaka, Valeriy; Ganguli, Supriya

    2001-10-01

    Predictive capabilities of the data-driven models of the systems with complex multi-scale dynamics depend on the quality and amount of the available data and on the algorithms used to extract generalized mappings. Availability of the real-time high-resolution data constantly increases in many fields of practical interest. However, the majority of advanced nonlinear algorithms, including neural networks (NN), can encounter a set of problems called "dimensionality curse" when applied to high-dimensional data. Nonstationarity of the system can also impose significant limitations on the size of training set which leads to poor generalization ability of the model. A very promising algorithm that combines the power of the best nonlinear techniques and tolerance to high-dimensional and incomplete data is support vector machine (SVM). We have summarized and demonstrated advantages of the SVM by applying it to two important and challenging problems: substorm forecasting from solar wind data and volatility forecasting from multi-scale stock and exchange market data. We have shown that performance of the SVM model for substorm prediction can be comparable to or be superior to that of the best existing models including NNs. The advantages of the SVM-based techniques are expected to be much more pronounced in future space-weather forecasting models, which will incorporate many types of high-dimensional, multi-scale input data once real-time availability of this information becomes technologically feasible. We have also demonstrated encouraging performance of the SVM in application to volatility prediction using S&P 500 stock index and USD-DM exchange rate data. Future applications of the SVM in the emerging field of high-frequency finance and its relation to existing models are also discussed.

  10. Refined two-index entropy and multiscale analysis for complex system

    NASA Astrophysics Data System (ADS)

    Bian, Songhan; Shang, Pengjian

    2016-10-01

    As a fundamental concept in describing complex system, entropy measure has been proposed to various forms, like Boltzmann-Gibbs (BG) entropy, one-index entropy, two-index entropy, sample entropy, permutation entropy etc. This paper proposes a new two-index entropy Sq,δ and we find the new two-index entropy is applicable to measure the complexity of wide range of systems in the terms of randomness and fluctuation range. For more complex system, the value of two-index entropy is smaller and the correlation between parameter δ and entropy Sq,δ is weaker. By combining the refined two-index entropy Sq,δ with scaling exponent h(δ), this paper analyzes the complexities of simulation series and classifies several financial markets in various regions of the world effectively.

  11. Multi-scale multireference configuration interaction calculations for large systems using localized orbitals: partition in zones.

    PubMed

    Chang, Cristian; Calzado, Carmen J; Ben Amor, Nadia; Sanchez Marin, Jose; Maynau, Daniel

    2012-09-14

    A new multireference configuration interaction method using localised orbitals is proposed, in which a molecular system is divided into regions of unequal importance. The advantage of dealing with local orbitals, i.e., the possibility to neglect long range interaction is enhanced. Indeed, while in the zone of the molecule where the important phenomena occur, the interaction cut off may be as small as necessary to get relevant results, in the most part of the system it can be taken rather large, so that results of good quality may be obtained at a lower cost. The method is tested on several systems. In one of them, the definition of the various regions is not based on topological considerations, but on the nature, σ or π, of the localised orbitals, which puts in evidence the generality of the approach.

  12. Systems Pharmacology: Network Analysis to Identify Multiscale Mechanisms of Drug Action

    PubMed Central

    Zhao, Shan; Iyengar, Ravi

    2013-01-01

    Systems approaches have long been used in pharmacology to understand drug action at the organ and organismal levels. The application of computational and experimental systems biology approaches to pharmacology allows us to expand the definition of systems pharmacology to include network analyses at multiple scales of biological organization and to explain both therapeutic and adverse effects of drugs. Systems pharmacology analyses rely on experimental “omics” technologies that are capable of measuring changes in large numbers of variables, often at a genome-wide level, to build networks for analyzing drug action. A major use of omics technologies is to relate the genomic status of an individual to the therapeutic efficacy of a drug of interest. Combining pathway and network analyses, pharmacokinetic and pharmacodynamic models, and a knowledge of polymorphisms in the genome will enable the development of predictive models of therapeutic efficacy. Network analyses based on publicly available databases such as the U.S. Food and Drug Administration’s Adverse Event Reporting System allow us to develop an initial understanding of the context within which molecular-level drug-target interactions can lead to distal effectors in a process that results in adverse phenotypes at the organ and organismal levels. The current state of systems pharmacology allows us to formulate a set of questions that could drive future research in the field. The long-term goal of such research is to develop polypharmacology for complex diseases and predict therapeutic efficacy and adverse event risk for individuals prior to commencement of therapy. PMID:22235860

  13. The Magentospheric Multiscale Constellation

    NASA Technical Reports Server (NTRS)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  14. The Magnetospheric Multiscale Constellation

    NASA Astrophysics Data System (ADS)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2016-03-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  15. The Magentospheric Multiscale Constellation

    NASA Technical Reports Server (NTRS)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  16. Magnetospheric Multiscale (MMS)

    NASA Image and Video Library

    2017-09-27

    Propulsion engineer measures the flight filters during the receiving inspection. Learn more about MMS at www.nasa.gov/mms Credit NASA/Goddard The Magnetospheric Multiscale, or MMS, will study how the sun and the Earth's magnetic fields connect and disconnect, an explosive process that can accelerate particles through space to nearly the speed of light. This process is called magnetic reconnection and can occur throughout all space. NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  17. The Magnetospheric Multiscale Constellation

    NASA Technical Reports Server (NTRS)

    Tooley, C. R.; Black, R. K.; Robertson, B. P.; Stone, J. M.; Pope, S. E.; Davis, G. T.

    2015-01-01

    The Magnetospheric Multiscale (MMS) mission is the fourth mission of the Solar Terrestrial Probe (STP) program of the National Aeronautics and Space Administration (NASA). The MMS mission was launched on March 12, 2015. The MMS mission consists of four identically instrumented spin-stabilized observatories which are flown in formation to perform the first definitive study of magnetic reconnection in space. The MMS mission was presented with numerous technical challenges, including the simultaneous construction and launch of four identical large spacecraft with 100 instruments total, stringent electromagnetic cleanliness requirements, closed-loop precision maneuvering and pointing of spinning flexible spacecraft, on-board GPS based orbit determination far above the GPS constellation, and a flight dynamics design that enables formation flying with separation distances as small as 10 km. This paper describes the overall mission design and presents an overview of the design, testing, and early on-orbit operation of the spacecraft systems and instrument suite.

  18. Multi-Scale Hydrometeorological Modeling, Land Data Assimilation and Parameter Estimation with the Land Information System

    NASA Technical Reports Server (NTRS)

    Peters-Lidard, Christa D.; Kumar, Sujay V.; Santanello, Joseph A., Jr.; Reichle, Rolf H.

    2009-01-01

    The Land Information System (LIS; http://lis.gsfc.nasa.gov; Kumar et al., 2006; Peters- Lidard et al.,2007) is a flexible land surface modeling framework that has been developed with the goal of integrating satellite- and ground-based observational data products and advanced land surface modeling techniques to produce optimal fields of land surface states and fluxes. As such, LIS represents a step towards the next generation land component of an integrated Earth system model. In recognition of LIS object-oriented software design, use and impact in the land surface and hydrometeorological modeling community, the LIS software was selected ase co-winner of NASA's 2005 Software of the Year award. LIS facilitates the integration of observations from Earth-observing systems and predictions and forecasts from Earth System and Earth science models into the decision-making processes of partnering agency and national organizations. Due to its flexible software design, LIS can serve both as a Problem Solving Environment (PSE) for hydrologic research to enable accurate global water and energy cycle predictions, and as a Decision Support System (DSS) to generate useful information for application areas including disaster management, water resources management, agricultural management, numerical weather prediction, air quality and military mobility assessment. LIS has evolved from two earlier efforts North American Land Data Assimilation System (NLDAS; Mitchell et al. 2004) and Global Land Data Assimilation System (GLDAS; Rodell al. 2004) that focused primarily on improving numerical weather prediction skills by improving the characterization of the land surface conditions. Both of GLDAS and NLDAS now use specific configurations of the LIS software in their current implementations. In addition, LIS was recently transitioned into operations at the US Air Force Weather Agency (AFWA) to ultimately replace their Agricultural Meteorology (AGRMET) system, and is also used routinely by

  19. Multi-Scale Hydrometeorological Modeling, Land Data Assimilation and Parameter Estimation with the Land Information System

    NASA Technical Reports Server (NTRS)

    Peters-Lidard, Christa D.

    2011-01-01

    The Land Information System (LIS; http://lis.gsfc.nasa.gov) is a flexible land surface modeling framework that has been developed with the goal of integrating satellite-and ground-based observational data products and advanced land surface modeling techniques to produce optimal fields of land surface states and fluxes. As such, LIS represents a step towards the next generation land component of an integrated Earth system model. In recognition of LIS object-oriented software design, use and impact in the land surface and hydrometeorological modeling community, the LIS software was selected as a co-winner of NASA?s 2005 Software of the Year award.LIS facilitates the integration of observations from Earth-observing systems and predictions and forecasts from Earth System and Earth science models into the decision-making processes of partnering agency and national organizations. Due to its flexible software design, LIS can serve both as a Problem Solving Environment (PSE) for hydrologic research to enable accurate global water and energy cycle predictions, and as a Decision Support System (DSS) to generate useful information for application areas including disaster management, water resources management, agricultural management, numerical weather prediction, air quality and military mobility assessment. LIS has e volved from two earlier efforts -- North American Land Data Assimilation System (NLDAS) and Global Land Data Assimilation System (GLDAS) that focused primarily on improving numerical weather prediction skills by improving the characterization of the land surface conditions. Both of GLDAS and NLDAS now use specific configurations of the LIS software in their current implementations.In addition, LIS was recently transitioned into operations at the US Air Force Weather Agency (AFWA) to ultimately replace their Agricultural Meteorology (AGRMET) system, and is also used routinely by NOAA's National Centers for Environmental Prediction (NCEP)/Environmental Modeling

  20. Multi-Scale Hydrometeorological Modeling, Land Data Assimilation and Parameter Estimation with the Land Information System

    NASA Technical Reports Server (NTRS)

    Peters-Lidard, Christa D.; Kumar, Sujay V.; Santanello, Joseph A., Jr.; Reichle, Rolf H.

    2009-01-01

    The Land Information System (LIS; http://lis.gsfc.nasa.gov; Kumar et al., 2006; Peters- Lidard et al.,2007) is a flexible land surface modeling framework that has been developed with the goal of integrating satellite- and ground-based observational data products and advanced land surface modeling techniques to produce optimal fields of land surface states and fluxes. As such, LIS represents a step towards the next generation land component of an integrated Earth system model. In recognition of LIS object-oriented software design, use and impact in the land surface and hydrometeorological modeling community, the LIS software was selected ase co-winner of NASA's 2005 Software of the Year award. LIS facilitates the integration of observations from Earth-observing systems and predictions and forecasts from Earth System and Earth science models into the decision-making processes of partnering agency and national organizations. Due to its flexible software design, LIS can serve both as a Problem Solving Environment (PSE) for hydrologic research to enable accurate global water and energy cycle predictions, and as a Decision Support System (DSS) to generate useful information for application areas including disaster management, water resources management, agricultural management, numerical weather prediction, air quality and military mobility assessment. LIS has evolved from two earlier efforts North American Land Data Assimilation System (NLDAS; Mitchell et al. 2004) and Global Land Data Assimilation System (GLDAS; Rodell al. 2004) that focused primarily on improving numerical weather prediction skills by improving the characterization of the land surface conditions. Both of GLDAS and NLDAS now use specific configurations of the LIS software in their current implementations. In addition, LIS was recently transitioned into operations at the US Air Force Weather Agency (AFWA) to ultimately replace their Agricultural Meteorology (AGRMET) system, and is also used routinely by

  1. Hybrid models for chemical reaction networks: Multiscale theory and application to gene regulatory systems.

    PubMed

    Winkelmann, Stefanie; Schütte, Christof

    2017-09-21

    Well-mixed stochastic chemical kinetics are properly modeled by the chemical master equation (CME) and associated Markov jump processes in molecule number space. If the reactants are present in large amounts, however, corresponding simulations of the stochastic dynamics become computationally expensive and model reductions are demanded. The classical model reduction approach uniformly rescales the overall dynamics to obtain deterministic systems characterized by ordinary differential equations, the well-known mass action reaction rate equations. For systems with multiple scales, there exist hybrid approaches that keep parts of the system discrete while another part is approximated either using Langevin dynamics or deterministically. This paper aims at giving a coherent overview of the different hybrid approaches, focusing on their basic concepts and the relation between them. We derive a novel general description of such hybrid models that allows expressing various forms by one type of equation. We also check in how far the approaches apply to model extensions of the CME for dynamics which do not comply with the central well-mixed condition and require some spatial resolution. A simple but meaningful gene expression system with negative self-regulation is analysed to illustrate the different approximation qualities of some of the hybrid approaches discussed. Especially, we reveal the cause of error in the case of small volume approximations.

  2. Multiscale Systems Modeling of Male Reproductive Tract Defects: from Genes to Populations (SOT)

    EPA Science Inventory

    The reproductive tract is a complex, integrated organ system with diverse embryology and unique sensitivity to prenatal environmental exposures that disrupt morphoregulatory processes and endocrine signaling. U.S. EPA’s in vitro high-throughput screening (HTS) database (ToxCastDB...

  3. Hybrid models for chemical reaction networks: Multiscale theory and application to gene regulatory systems

    NASA Astrophysics Data System (ADS)

    Winkelmann, Stefanie; Schütte, Christof

    2017-09-01

    Well-mixed stochastic chemical kinetics are properly modeled by the chemical master equation (CME) and associated Markov jump processes in molecule number space. If the reactants are present in large amounts, however, corresponding simulations of the stochastic dynamics become computationally expensive and model reductions are demanded. The classical model reduction approach uniformly rescales the overall dynamics to obtain deterministic systems characterized by ordinary differential equations, the well-known mass action reaction rate equations. For systems with multiple scales, there exist hybrid approaches that keep parts of the system discrete while another part is approximated either using Langevin dynamics or deterministically. This paper aims at giving a coherent overview of the different hybrid approaches, focusing on their basic concepts and the relation between them. We derive a novel general description of such hybrid models that allows expressing various forms by one type of equation. We also check in how far the approaches apply to model extensions of the CME for dynamics which do not comply with the central well-mixed condition and require some spatial resolution. A simple but meaningful gene expression system with negative self-regulation is analysed to illustrate the different approximation qualities of some of the hybrid approaches discussed. Especially, we reveal the cause of error in the case of small volume approximations.

  4. Using Multi-scale Modeling System to Study the Interactions between Clouds, Precipitation, Aerosols, Radiation and Land Surface

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2006-01-01

    nesting technique. A review of developments, improvements and applications of cloud models (GCE and WRF) at Goddard will be presented in this talk. In particular, a new approach to using multi-scale modeling system to study the interactions between clouds, precipitation, aerosols and land will be presented.

  5. Using Multi-scale Modeling System to Study the Interactions between Clouds, Precipitation, Aerosols, Radiation and Land Surface

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2006-01-01

    technique. A review of developments, improvements and applications of cloud models (GCE and WRF) at Goddard wlll be is presented in this talk. In particular, a new approach to using multi-scale modeling system to study the interactions between clouds, precipitation, aerosols and land will be presented.

  6. Using Multi-scale Modeling System to Study the Interactions between Clouds, Precipitation, Aerosols, Radiation and Land Surface

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2006-01-01

    developments, improvements and applications of cloud models (GCE and WRF) at Goddard will be presented in this talk. In particular, a new approach to using multi-scale modeling system to study the interactions between clouds, precipitation, aerosols and land will be presented.

  7. Dielectric response based characterization and strength prediction of cementitious materials

    NASA Astrophysics Data System (ADS)

    Manchiryal, Ram Kishore

    Electrical property based methods are powerful tools to sense the properties of cement based materials. Among the several non-invasive investigative techniques, those based on monitoring the electrical properties during the initial setting and in the subsequent hardening period have immense potential in performance prediction of concrete. Electrical impedance spectroscopy (EIS) has emerged as one of the promising techniques to non-invasively probe the microstructure and property development in cement based materials. This thesis reports the results of a systematic investigation carried out to understand the influence of material parameters on the dielectric response of cement pastes and concretes, and also a methodology to property prediction in cementitious system using electrical properties. The influence of cement type, water-to-cementing materials ratio (w/cm), and the presence of fly ash as a cement replacement material on the conductivity of cement pastes is studied. The electrical conductivity---time relationships of cement pastes and concretes are expressed using a model that facilitates the extraction of initial and final conductivities, and a characteristic time parameter. These terms are used to derive information about the microstructural changes occurring with time in cement pastes. The experimental results are subjected to a range analysis to isolate the significant factors and factor interactions that influence the initial and final conductivities as well as the time parameter from the conductivity-time model for concrete mixtures. The material parameters that influence the measured conductivity are identified and their influence quantified. The changes in dielectric constant and conductivity spectra of cement paste and concretes are attributed to the polarization phenomena. There is an observed dielectric enhancement for fly ash modified pastes. The dielectric response of concrete is very similar to that of pastes, and the effect of dilution by the

  8. A Recursive Multiscale Correlation-Averaging Algorithm for an Automated Distributed Road Condition Monitoring System

    SciTech Connect

    Ndoye, Mandoye; Barker, Alan M; Krogmeier, James; Bullock, Darcy

    2011-01-01

    A signal processing approach is proposed to jointly filter and fuse spatially indexed measurements captured from many vehicles. It is assumed that these measurements are influenced by both sensor noise and measurement indexing uncertainties. Measurements from low-cost vehicle-mounted sensors (e.g., accelerometers and Global Positioning System (GPS) receivers) are properly combined to produce higher quality road roughness data for cost-effective road surface condition monitoring. The proposed algorithms are recursively implemented and thus require only moderate computational power and memory space. These algorithms are important for future road management systems, which will use on-road vehicles as a distributed network of sensing probes gathering spatially indexed measurements for condition monitoring, in addition to other applications, such as environmental sensing and/or traffic monitoring. Our method and the related signal processing algorithms have been successfully tested using field data.

  9. Multi-scale and Multi-physics Numerical Methods for Modeling Transport in Mesoscopic Systems

    DTIC Science & Technology

    2014-10-13

    Triangle Park, NC 27709-2211 Transport, Electromagnetic Phenomena, nano-electronics, ion channels , layered media REPORT DOCUMENTATION PAGE 11. SPONSOR...DFT for quantum systems. (3) numerical methods for computation of electrostatics in ion- channel transport, (4) a new parallel solver for elliptic...10.00 Received Paper 9.00 Huimin Lin, Huazhong Tang, Wei Cai. Accuracy and efficiency in computing electrostatic potentialfor an ion channel model in

  10. Design strategies for human & earth systems modeling to meet emerging multi-scale decision support needs

    NASA Astrophysics Data System (ADS)

    Spak, S.; Pooley, M.

    2012-12-01

    The next generation of coupled human and earth systems models promises immense potential and grand challenges as they transition toward new roles as core tools for defining and living within planetary boundaries. New frontiers in community model development include not only computational, organizational, and geophysical process questions, but also the twin objectives of more meaningfully integrating the human dimension and extending applicability to informing policy decisions on a range of new and interconnected issues. We approach these challenges by posing key policy questions that require more comprehensive coupled human and geophysical models, identify necessary model and organizational processes and outputs, and work backwards to determine design criteria in response to these needs. We find that modular community earth system model design must: * seamlessly scale in space (global to urban) and time (nowcasting to paleo-studies) and fully coupled on all component systems * automatically differentiate to provide complete coupled forward and adjoint models for sensitivity studies, optimization applications, and 4DVAR assimilation across Earth and human observing systems * incorporate diagnostic tools to quantify uncertainty in couplings, and in how human activity affects them * integrate accessible community development and application with JIT-compilation, cloud computing, game-oriented interfaces, and crowd-sourced problem-solving We outline accessible near-term objectives toward these goals, and describe attempts to incorporate these design objectives in recent pilot activities using atmosphere-land-ocean-biosphere-human models (WRF-Chem, IBIS, UrbanSim) at urban and regional scales for policy applications in climate, energy, and air quality.

  11. Discovering Free Energy Basins for Macromolecular Systems via Guided Multiscale Simulation

    PubMed Central

    Sereda, Yuriy V.; Singharoy, Abhishek B.; Jarrold, Martin F.; Ortoleva, Peter J.

    2012-01-01

    An approach for the automated discovery of low free energy states of macromolecular systems is presented. The method does not involve delineating the entire free energy landscape but proceeds in a sequential free energy minimizing state discovery, i.e., it first discovers one low free energy state and then automatically seeks a distinct neighboring one. These states and the associated ensembles of atomistic configurations are characterized by coarse-grained variables capturing the large-scale structure of the system. A key facet of our approach is the identification of such coarse-grained variables. Evolution of these variables is governed by Langevin dynamics driven by thermal-average forces and mediated by diffusivities, both of which are constructed by an ensemble of short molecular dynamics runs. In the present approach, the thermal-average forces are modified to account for the entropy changes following from our knowledge of the free energy basins already discovered. Such forces guide the system away from the known free energy minima, over free energy barriers, and to a new one. The theory is demonstrated for lactoferrin, known to have multiple energy-minimizing structures. The approach is validated using experimental structures and traditional molecular dynamics. The method can be generalized to enable the interpretation of nanocharacterization data (e.g., ion mobility – mass spectrometry, atomic force microscopy, chemical labeling, and nanopore measurements). PMID:22423635

  12. Discovering free energy basins for macromolecular systems via guided multiscale simulation.

    PubMed

    Sereda, Yuriy V; Singharoy, Abhishek B; Jarrold, Martin F; Ortoleva, Peter J

    2012-07-26

    An approach for the automated discovery of low free energy states of macromolecular systems is presented. The method does not involve delineating the entire free energy landscape but proceeds in a sequential free energy minimizing state discovery; i.e., it first discovers one low free energy state and then automatically seeks a distinct neighboring one. These states and the associated ensembles of atomistic configurations are characterized by coarse-grained variables capturing the large-scale structure of the system. A key facet of our approach is the identification of such coarse-grained variables. Evolution of these variables is governed by Langevin dynamics driven by thermal-average forces and mediated by diffusivities, both of which are constructed by an ensemble of short molecular dynamics runs. In the present approach, the thermal-average forces are modified to account for the entropy changes following from our knowledge of the free energy basins already discovered. Such forces guide the system away from the known free energy minima, over free energy barriers, and to a new one. The theory is demonstrated for lactoferrin, known to have multiple energy-minimizing structures. The approach is validated using experimental structures and traditional molecular dynamics. The method can be generalized to enable the interpretation of nanocharacterization data (e.g., ion mobility-mass spectrometry, atomic force microscopy, chemical labeling, and nanopore measurements).

  13. Multiscale Systems-Pharmacology Pipeline to Assess the Prophylactic Efficacy of NRTIs Against HIV-1.

    PubMed

    Duwal, S; Sunkara, V; von Kleist, M

    2016-07-01

    While HIV-1 continues to spread, the use of antivirals in preexposure prophylaxis (PrEP) has recently been suggested. Here we present a modular systems pharmacology modeling pipeline, predicting PrEP efficacy of nucleotide reverse transcriptase inhibitors (NRTIs) at the scale of reverse transcription, target-cell, and systemic infection and after repeated viral exposures, akin to clinical trials. We use this pipeline to benchmark the prophylactic efficacy of all currently approved NRTIs in wildtype and mutant viruses. By integrating pharmacokinetic models, we find that intracellular tenofovir-diphosphate builds up too slowly to halt infection when taken "on demand" and that lamivudine may substitute emtricitabine in PrEP combinations. Lastly, we delineate factors confounding clinical PrEP efficacy estimates and provide a method to overcome these. The presented framework is useful to screen and optimize PrEP candidates and strategies and to understand their clinical efficacy by integrating the diverse scales which determine PrEP efficacy. © 2016 The Authors CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals, Inc. on behalf of American Society for Clinical Pharmacology and Therapeutics.

  14. Multi-Scale Autoregressive Processes

    DTIC Science & Technology

    1989-06-01

    rationnelles et leurs langages," Mas- son 1984, Collection "Etudes et Recherches en Informatique". [12] J.L. DUNAU, "Etude d’une classe de marches...June 1989 LIDS-P-1880 Multi-Scale Autoregressive Processes Michele Basseville’ Albert Benveniste’ Institut de Recherche en Informatique et Systemes...Centre National de la Recherche Scientifique (CNRS) and A.B. is also with Institut National de Recherche en Informatique et en Automatique (INRIA). The

  15. On the combined use of radar systems for multi-scale imaging of transport infrastructures

    NASA Astrophysics Data System (ADS)

    Catapano, I.; Bavusi, M.; Loperte, A.; Crocco, L.; Soldovieri, F.

    2012-04-01

    Ground Penetrating Radar (GPR) systems are worth to be considered as in situ non invasive diagnostic tools capable of assessing stability and integrity of transport infrastructures. As a matter of fact, by exploiting the interactions among probing electromagnetic waves and hidden objects, they provide images of the inner status of the spatial region under test from which infer risk factors, such as deformations and oxidization of the reinforcement bars as well as water infiltrations, crack and air gaps. With respect to the assessment of concrete infrastructures integrity, the reconstruction capabilities of GPR systems have been widely investigated [1,2]. However, the demand for diagnostic tools capable of providing detailed and real time information motivates the design and the performance evaluation of novel technologies and data processing methodologies aimed not only to effectively detect hidden anomalies but also to estimate their geometrical features. In this framework, this communication aims at investigating the advantages offered by the joint use of two GPR systems both of them equipped with a specific tomographic imaging approach. The first considered system is a time domain GPR equipped with a 1.5GHz shielded antenna, which is suitable for quick and good resolution surveys of the shallower layers of the structure. As second system, the holographic radar Rascan-4/4000 [3,4] is taken into account, due to its capability of providing holograms of hidden targets from the amplitude of the interference signal arising between the backscattered field and a reference signal. The imaging capabilities of both the GPR tools are enhanced by means of model based data processing approaches, which afford the imaging as a linear inverse scattering problem. Mathematical details on the inversion strategies will be provided at the conference. The combined use of the above GPR systems allows to perform multi-resolution surveys of the region under test, whose aim is, first of

  16. Solving water quality problems in agricultural landscapes: New approaches for these nonlinear, multiprocess, multiscale systems

    NASA Astrophysics Data System (ADS)

    Belmont, Patrick; Foufoula-Georgiou, Efi

    2017-04-01

    Changes in climate and agricultural practices are putting pressure on agroenvironmental systems all over the world. Predicting the effects of future management or conservation actions has proven exceptionally challenging in these complex landscapes. We present a perspective, gained from a decade of research and stakeholder involvement in the Minnesota River Basin, where research findings have influenced solutions and policy in directions not obvious at the outset. Our approach has focused on identifying places, times, and processes of accelerated change and developing reduced complexity predictive frameworks that can inform mitigation actions.

  17. Northeast Coastal Ocean Forecast System (NECOFS): A Multi-scale Global-Regional-Estuarine FVCOM Model

    NASA Astrophysics Data System (ADS)

    Beardsley, R. C.; Chen, C.

    2014-12-01

    The Northeast Coastal Ocean Forecast System (NECOFS) is a global-regional-estuarine integrated atmosphere/surface wave/ocean forecast model system designed for the northeast US coastal region covering a computational domain from central New Jersey to the eastern end of the Scotian Shelf. The present system includes 1) the mesoscale meteorological model WRF (Weather Research and Forecasting); 2) the regional-domain FVCOM covering the Gulf of Maine/Georges Bank/New England Shelf region (GOM-FVCOM); 3) the unstructured-grid surface wave model (FVCOM-SWAVE) modified from SWAN with the same domain as GOM-FVCOM; 3) the Mass coastal FVCOM with inclusion of inlets, estuaries and intertidal wetlands; and 4) three subdomain wave-current coupled inundation FVCOM systems in Scituate, MA, Hampton River, NH and Mass Bay, MA. GOM-FVCOM grid features unstructured triangular meshes with horizontal resolution of ~ 0.3-25 km and a hybrid terrain-following vertical coordinate with a total of 45 layers. The Mass coastal FVCOM grid is configured with triangular meshes with horizontal resolution up to ~10 m, and 10 layers in the vertical. Scituate, Hampton River and Mass Bay inundation model grids include both water and land with horizontal resolution up to ~5-10 m and 10 vertical layers. GOM-FVCOM is driven by surface forcing from WRF model output configured for the region (with 9-km resolution), the COARE3 bulk air-sea flux algorithm, local river discharges, and tidal forcing constructed by eight constituents and subtidal forcing on the boundary nested to the Global-FVCOM. SWAVE is driven by the same WRF wind field with wave forcing at the boundary nested to Wave Watch III configured for the northwestern Atlantic region. The Mass coastal FVCOM and three inundation models are connected with GOM-FVCOM through one-way nesting in the common boundary zones. The Mass coastal FVCOM is driven by the same surface forcing as GOM-FVCOM. The nesting boundary conditions for the inundation models

  18. Towards a virtual lung: multi-scale, multi-physics modelling of the pulmonary system

    PubMed Central

    Burrowes, K.S; Swan, A.J; Warren, N.J; Tawhai, M.H

    2008-01-01

    The essential function of the lung, gas exchange, is dependent on adequate matching of ventilation and perfusion, where air and blood are delivered through complex branching systems exposed to regionally varying transpulmonary and transmural pressures. Structure and function in the lung are intimately related, yet computational models in pulmonary physiology usually simplify or neglect structure. The geometries of the airway and vascular systems and their interaction with parenchymal tissue have an important bearing on regional distributions of air and blood, and therefore on whole lung gas exchange, but this has not yet been addressed by modelling studies. Models for gas exchange have typically incorporated considerable detail at the level of chemical reactions, with little thought for the influence of structure. To date, relatively little attention has been paid to modelling at the cellular or subcellular level in the lung, or to linking information from the protein structure/interaction and cellular levels to the operation of the whole lung. We review previous work in developing anatomically based models of the lung, airways, parenchyma and pulmonary vasculature, and some functional studies in which these models have been used. Models for gas exchange at several spatial scales are briefly reviewed, and the challenges and benefits from modelling cellular function in the lung are discussed. PMID:18593661

  19. A multi-scale hydroclimatological assessment of perennial bioenergy cropping systems

    NASA Astrophysics Data System (ADS)

    Georgescu, Matei; Miguez-Macho, Gonzalo; Wagner, Melissa; Wang, Meng; Bagley, Justin; Vanloocke, Andrew

    2017-04-01

    Hydro-climatic sustainability associated with deployment of perennial bioenergy cropping systems requires a holistic approach that extends beyond merely carbon accounting. Here, we present results from a five-year National Science Foundation project (Water Sustainability and Climate initiative) focused on development of geographically explicit maps depicting sustainable regional "hot-spots" of perennial biomass energy expansion in the United States (U.S.). Using short-term/high-resolution (1 year/1km) and climate scale/medium range resolution (10 years/20km) simulations with the Weather Research and Forecasting (WRF) system, an atmospheric code coupled to a suite of land surface models, we quantify impacts on the hydrologic cycle, and examine the effect of energy crops (e.g., miscanthus and switchgrass) on subsurface hydrology (e.g., soil moisture, groundwater impacts) and atmospheric dynamics. We avoid the competition with food crops by focusing energy crop deployment exclusively on abandoned and degraded farmland regions within the Continental U.S. Finally, assessment of photosynthetic production of bioenergy crops is made, based on hydro-climatic constraints associated with varying scenarios of perennial bioenergy crop deployment simulated with WRF.

  20. Multi-scale InSAR analysis of aseismic creep across the San Andreas, Calevaras,and Hayward Fault systems

    NASA Astrophysics Data System (ADS)

    Agram, P. S.; Simons, M.

    2011-12-01

    We apply the Multi-scale Interferometric Time-series (MInTS) technique, developed at Caltech,to study spatial variations in aseismic creep across the San Andreas, Calaveras and Hayward Faultsystems in Central California.Interferometric Synthetic Aperture Radar (InSAR) Time-series methods estimate the spatio-temporal evolution of surface deformation using multiple SAR interferograms. Traditional time-series analysis techniques like persistent scatterers and short baseline methods assume the statistical independence of InSAR phase measurements over space and time when estimating deformation. However, existing atmospheric phase screen models clearly show that noise in InSAR phase observations is correlated over the spatial domain. MInTS is an approach designed to exploit the correlation of phase observations over space to significantly improve the signal-to-noise ratio in the estimated deformation time-series compared to the traditional time-series InSAR techniques. The MInTS technique reduces the set of InSAR observations to a set of almost uncorrelated observations at various spatial scales using wavelets. Traditional inversion techniques can then be applied to the wavelet coefficients more effectively. Creep across the Central San Andreas Fault and the Hayward Fault has been studied previously using C-band (6 cm wavelength) ERS data, but detailed analysis of the transition zone between the San Andreas and Hayward Faults was not possible due to severe decorrelation. Improved coherence at L-band (24 cm wavelength) significantly improves the spatial coverage of the estimated deformation signal in our ALOS PALSAR data set. We analyze 450 ALOS PALSAR interferograms processed using 175 SAR images acquired between Dec 2006 and Dec 2010 that cover the area along the San Andreas Fault System from Richmond in the San Francisco Bay Area to Maricopa in the San Joaquin Valley.We invert the InSAR phase observations to estimate the constant Line-of-Sight (LOS) deformation

  1. Text Stream Trend Analysis using Multiscale Visual Analytics with Applications to Social Media Systems

    SciTech Connect

    Steed, Chad A; Beaver, Justin M; BogenII, Paul L.; Drouhard, Margaret MEG G; Pyle, Joshua M

    2015-01-01

    In this paper, we introduce a new visual analytics system, called Matisse, that allows exploration of global trends in textual information streams with specific application to social media platforms. Despite the potential for real-time situational awareness using these services, interactive analysis of such semi-structured textual information is a challenge due to the high-throughput and high-velocity properties. Matisse addresses these challenges through the following contributions: (1) robust stream data management, (2) automated sen- timent/emotion analytics, (3) inferential temporal, geospatial, and term-frequency visualizations, and (4) a flexible drill-down interaction scheme that progresses from macroscale to microscale views. In addition to describing these contributions, our work-in-progress paper concludes with a practical case study focused on the analysis of Twitter 1% sample stream information captured during the week of the Boston Marathon bombings.

  2. EMAPS: An Efficient Multiscale Approach to Plasma Systems with Non-MHD Scale Effects

    SciTech Connect

    Omelchenko, Yuri A.; Karimabadi, Homa

    2014-10-14

    Using Discrete-Event Simulation (DES) as a novel paradigm for time integration of large-scale physics-driven systems, we have achieved significant breakthroughs in simulations of multi-dimensional magnetized plasmas where ion kinetic and finite Larmor radius (FLR) and Hall effects play a crucial role. For these purposes we apply a unique asynchronous simulation tool: a parallel, electromagnetic Particle-in-Cell (PIC) code, HYPERS (Hybrid Particle Event-Resolved Simulator), which treats plasma electrons as a charge neutralizing fluid and solves a self-consistent set of non-radiative Maxwell, electron fluid equations and ion particle equations on a structured computational grid. HYPERS enables adaptive local time steps for particles, fluid elements and electromagnetic fields. This ensures robustness (stability) and efficiency (speed) of highly dynamic and nonlinear simulations of compact plasma systems such spheromaks, FRCs, ion beams and edge plasmas. HYPERS is a unique asynchronous code that has been designed to serve as a test bed for developing multi-physics applications not only for laboratory plasma devices but generally across a number of plasma physics fields, including astrophysics, space physics and electronic devices. We have made significant improvements to the HYPERS core: (1) implemented a new asynchronous magnetic field integration scheme that preserves local divB=0 to within round-off errors; (2) Improved staggered-grid discretizations of electric and magnetic fields. These modifications have significantly enhanced the accuracy and robustness of 3D simulations. We have conducted first-ever end-to-end 3D simulations of merging spheromak plasmas. The preliminary results show: (1) tilt-driven relaxation of a freely expanding spheromak to an m=1 Taylor helix configuration and (2) possibility of formation of a tilt-stable field-reversed configuration via merging and magnetic reconnection of two double-sided spheromaks with opposite helicities.

  3. A multiscale electrical survey of a lateritic soil system in the rain forest of Cameroon

    NASA Astrophysics Data System (ADS)

    Robain, Henri; Descloitres, Marc; Ritz, Michel; Atangana, Quantin Yene

    1996-06-01

    Resistivity investigations were carried out on an elementary watershed in SW Cameroon, firstly to assess the applicability of direct-current (DC) resistivity methods to solve various pedological problems in intertropical regions, and subsequently to determine the relationships between electrical resistivities and pedological properties of lateritic soil systems. The survey included measurements in pits with a small Wenner fixed-spacing array (SWA), vertical electrical soundings (VES) and vertical electrical "quick soundings" (VEQS) both using the Schlumberger configuration. The VES data were interpreted using a conventional multilayer inversion program to obtain best-fit models. Constraints to the interpretation of these data were provided by SWA and pedological information from existing observation pits. The results of the interpretation reveal five distinct geoelectrical layers overlying a resistive bedrock. The first is a thin organo-mineral upper layer with low resistivities in the range 250-450 Ωm. The second layer corresponds to micro-aggregated clayey materials and is more resistive (1300-1800 Ωm). The third represents the main part of ferruginous materials and is even more resistive (2000-4500 Ωm). The fourth corresponds to unsaturated saprolite and the last to saturated saprolite (ground water) with resistivities ranging from 800 to 1500 Ωm and from 150 to 250 Ωm, respectively. Estimates of soil volumes for the entire study area were obtained from VEQS interpretations. Most of the soil cover corresponds to saprolite (74%, {1}/{4} being saturated by ground water), while topsoil and ferruginous materials represent 14 and 12%, respectively. Finally, geophysical results based upon 1-D inversion provide a satisfactory approximation of the various lateritic components' 3-D geometry over the watershed. The study provides original quantitative results concerning the behaviour of intertropical soil systems as well as some geomorphological keys for soil mapping

  4. MULTISCALE THERMOHYDROLOGIC MODEL

    SciTech Connect

    T.A. Buscheck

    2001-12-21

    The purpose of the Multiscale Thermohydrologic Model (MSTHM) is to describe the thermohydrologic evolution of the near-field environment (NFE) and engineered barrier system (EBS) throughout the potential high-level nuclear waste repository at Yucca Mountain for a particular engineering design (CRWMS M&O 2000c). The process-level model will provide thermohydrologic (TH) information and data (such as in-drift temperature, relative humidity, liquid saturation, etc.) for use in other technical products. This data is provided throughout the entire repository area as a function of time. The MSTHM couples the Smeared-heat-source Drift-scale Thermal-conduction (SDT), Line-average-heat-source Drift-scale Thermohydrologic (LDTH), Discrete-heat-source Drift-scale Thermal-conduction (DDT), and Smeared-heat-source Mountain-scale Thermal-conduction (SMT) submodels such that the flow of water and water vapor through partially-saturated fractured rock is considered. The MSTHM accounts for 3-D drift-scale and mountain-scale heat flow, repository-scale variability of stratigraphy and infiltration flux, and waste package (WP)-to-WP variability in heat output from WPs. All submodels use the nonisothermal unsaturated-saturated flow and transport (NUFT) simulation code. The MSTHM is implemented in several data-processing steps. The four major steps are: (1) submodel input-file preparation, (2) execution of the four submodel families with the use of the NUFT code, (3) execution of the multiscale thermohydrologic abstraction code (MSTHAC), and (4) binning and post-processing (i.e., graphics preparation) of the output from MSTHAC. Section 6 describes the MSTHM in detail. The objectives of this Analyses and Model Report (AMR) are to investigate near field (NF) and EBS thermohydrologic environments throughout the repository area at various evolution periods, and to provide TH data that may be used in other process model reports.

  5. Short fiber-reinforced cementitious composites manufactured by extrusion technology

    NASA Astrophysics Data System (ADS)

    Mu, Bin

    The use of short fibers in the cement-based composites is more preferable due to the simplicity and economic nature in fabrication. The short fiber-reinforced cementitious composite (SFRCC) manufactured by the extrusion method show a great improvement in both strength and toughness as compared to the fiber-reinforced composites made by traditional casting methods. This improvement can be attributed to the achievement of low porosity and good interfacial bond in SFRCC under high shear and compressive stress during the extrusion process. In the present study, products of cylinders, sheets, pipes and honeycomb panels incorporating various mineral admixtures such as slag, silica fume, and metakaolin have been manufactured by the extrusion technology. Two kinds of short fibers, ductile polyvinyl alcohol (PVA) fibers and stronger but less ductile glass fibers, were used as the reinforcement in the products. After the specimens were extruded, tension, bending and impact tests were performed to study the mechanical properties of these products. The rheology test was performed for each mix to determine its viscoelastic properties. In addition, X-ray diffraction (XRD) and scanning electronic microscopy (SEM) technology were employed to get an insight view of the mechanism. A freezing and thawing experiment (ASTM C666) was also carried to investigate the durability of the specimens. Based on these experimental results, the reinforcing behaviors of these two short fibers were investigated. The enhancing effects of silica fume and metakaolin on the extrudates were compared and discussed. Finally, the optimum amount of silica fume and slag was proposed. Since the key point for a successful extrusion is the properly designed rheology which controls both internal and external flow properties of extrudate, a nonlinear viscoelastic model was applied to investigate the rheological behavior of a movable fresh cementitious composite in an extruder channel. The velocity profile of the

  6. Modeling the Turkish Straits System with a Multi-Scale Model

    NASA Astrophysics Data System (ADS)

    Kemal Cambazoglu, Mustafa; Blain, Cheryl Ann

    2010-05-01

    Two narrow, shallow straits, i.e. the Dardanelles and the Bosphorus, form a physical connection between the Marmara Sea and its adjacent water bodies, the Aegean Sea to the southwest and the Black Sea to the northeast. This collection of seas and straits is known as the Turkish Strait System (TSS). Saline, dense water from the Aegean flows in a deep, lower layer through the Marmara Sea to the Black Sea while fresher and lighter Black Sea water flows in a surface layer to the Aegean Sea. Flow within the TSS is often interpreted in terms of classic two-layer estuarine flow. Though the TSS dynamics are the result of interconnections between the straits and the ocean basins, earlier modeling efforts have focused dynamical studies on individual straits or seas. Often the geometric complexity, the broad range of spatial scales present, and the computational resources required to represent such disparity have prevented a study of the entire TSS as a whole. For this study, we utilize state-of-the-art modeling practices to capture the range of spatial scales, geometric complexity and interconnected dynamics of the TSS. A model based on unstructured grids has the resolution, using a minimum element edge length of 20 m, necessary to model flow in the narrow straits whose minimum width is approximately 600 m. The ADvanced CIRCulation Model (ADCIRC), solves the three-dimensional flow and transport equations using a finite element discretization with a terrain-following, generalized, stretched coordinate system applied in the vertical. Flexibility of the finite element mesh not only captures the fine scales within the straits but is also able to represent mesoscale variability in the Marmara Sea while coupling to a basin scale model in the Aegean and Black Seas. Basin-wide dynamics are captured by the HYbrid Coordinate Ocean Model, HYCOM, which applies the finite difference method over a structured grid to solve the primitive mass and momentum balance equations. HYCOM's hybrid

  7. Based on a multi-agent system for multi-scale simulation and application of household's LUCC: a case study for Mengcha village, Mizhi county, Shaanxi province.

    PubMed

    Chen, Hai; Liang, Xiaoying; Li, Rui

    2013-01-01

    Multi-Agent Systems (MAS) offer a conceptual approach to include multi-actor decision making into models of land use change. Through the simulation based on the MAS, this paper tries to show the application of MAS in the micro scale LUCC, and reveal the transformation mechanism of difference scale. This paper starts with a description of the context of MAS research. Then, it adopts the Nested Spatial Choice (NSC) method to construct the multi-scale LUCC decision-making model. And a case study for Mengcha village, Mizhi County, Shaanxi Province is reported. Finally, the potentials and drawbacks of the following approach is discussed and concluded. From our design and implementation of the MAS in multi-scale model, a number of observations and conclusions can be drawn on the implementation and future research directions. (1) The use of the LUCC decision-making and multi-scale transformation framework provides, according to us, a more realistic modeling of multi-scale decision making process. (2) By using continuous function, rather than discrete function, to construct the decision-making of the households is more realistic to reflect the effect. (3) In this paper, attempts have been made to give a quantitative analysis to research the household interaction. And it provides the premise and foundation for researching the communication and learning among the households. (4) The scale transformation architecture constructed in this paper helps to accumulate theory and experience for the interaction research between the micro land use decision-making and the macro land use landscape pattern. Our future research work will focus on: (1) how to rational use risk aversion principle, and put the rule on rotation between household parcels into model. (2) Exploring the methods aiming at researching the household decision-making over a long period, it allows us to find the bridge between the long-term LUCC data and the short-term household decision-making. (3) Researching the

  8. Effects of Iron Oxides on the Rheological Properties of Cementitious Slurry

    SciTech Connect

    Chung, Chul-Woo; Chun, Jaehun; Wang, Guohui; Um, Wooyong

    2014-04-02

    Iron oxide has been considered a promising host for immobilizing and encapsulating radioactive 99Tc (t1/2=2.1x105 year), which significantly enhances the stability of 99Tc within a cementitious waste form. However, the flow behavior of cementitious slurry containing iron oxide has never been investigated to ensure its workability, which directly influences the preparation and performance of the cementitious waste form monolith. Variation in the rheological properties of the cementitious slurry were studied using rheometry and ultrasonic wave reflection to understand the effects of various iron oxides (magnetite, hematite, ferrihydrite, and goethite) during the cement setting and stiffening processes. The rheological behavior significantly varied with the addition of different chemical compounds of iron oxides. Complementary microscopic characteristics such as colloidal vibration currents, morphology, and particle size distributions further suggest that the most adverse alteration of cement setting and stiffening behavior caused by the presence of goethite may be attributed to its acicular shape.

  9. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method.

    PubMed

    Alani, Amir M; Faramarzi, Asaad

    2015-06-10

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes.

  10. Experimental Observations of Multiscale Dynamics of Viscous Fluid Behavior: Implications in Volcanic Systems

    NASA Astrophysics Data System (ADS)

    Arciniega-Ceballos, A.; Spina, L.; Scheu, B.; Dingwell, D. B.

    2015-12-01

    We have investigated the dynamics of Newtonian fluids with viscosities (10-1000 Pa s; corresponding to mafic to intermediate silicate melts) during slow decompression, in a Plexiglas shock tube. As an analogue fluid we used silicon oil saturated with Argon gas for 72 hours. Slow decompression, dropping from 10 MPa to ambient pressure, acts as the excitation mechanism, initiating several processes with their own distinct timescales. The evolution of this multi-timescale phenomenon generates complex non-stationary microseismic signals, which have been recorded with 7 high-dynamic piezoelectric sensors located along the conduit. Correlation analysis of these time series with the associated high-speed imaging enables characterization of distinct phases of the dynamics of these viscous fluids and the extraction of the time and the frequency characteristics of the individual processes. We have identified fluid-solid elastic interaction, degassing, fluid mass expansion and flow, bubble nucleation, growth, coalescence and collapse, foam building and vertical wagging. All these processes (in fine and coarse scales) are sequentially coupled in time, occur within specific pressure intervals, and exhibit a localized distribution in space. Their coexistence and interactions constitute the stress field and driving forces that determine the dynamics of the system. Our observations point to the great potential of this experimental approach in the understanding of volcanic processes and volcanic seismicity.

  11. Multiscale Dynamics in Micro-porous Fractured Systems: Theory and Experiments

    NASA Astrophysics Data System (ADS)

    Ling, B.; Battiato, I.; Tartakovsky, A. M.; Oostrom, M.

    2015-12-01

    Soils and rock systems exhibit surfaces with complex micro-scale topological features. Understanding flow and solute transport over micro-patterned surfaces is essential to improve our predictive understanding of transport in structurally heterogeneous porous media, which provides insight of many environmental processes including CO2 sequestration and bioremediation. We are interested in seeking the relationship between surface topological structure and its impact on solute transport. We consider a thin fracture embedded in a permeable porous matrix. By means of homogenization technique, we upscale the transport equation and obtain a macro-scale dispersion coefficient which depends on the geometrical characteristic of the matrix, i.e. porous layer permeability and width. This expression generalizes a number of former studies, including the classical form of the Aris-Taylor dispersion coefficient and more recent results based on the assumption of purely diffusive mass transport in the matrix. Based on the upscaled equation, we provide a two-dimensional solution for the concentration profiles both inside the fracture and the matrix. Finally, we show good agreement between our theoretical predictions and the experimental data performed on a series of microfluidic cells with different matrix geometries/permeabilities for a wide range of Peclet numbers.

  12. A Multi-Scale Model of Hepcidin Promoter Regulation Reveals Factors Controlling Systemic Iron Homeostasis

    PubMed Central

    Muckenthaler, Martina U.; Legewie, Stefan

    2014-01-01

    Systemic iron homeostasis involves a negative feedback circuit in which the expression level of the peptide hormone hepcidin depends on and controls the iron blood levels. Hepcidin expression is regulated by the BMP6/SMAD and IL6/STAT signaling cascades. Deregulation of either pathway causes iron-related diseases such as hemochromatosis or anemia of inflammation. We quantitatively analyzed how BMP6 and IL6 control hepcidin expression. Transcription factor (TF) phosphorylation and reporter gene expression were measured under co-stimulation conditions, and the promoter was perturbed by mutagenesis. Using mathematical modeling, we systematically analyzed potential mechanisms of cooperative and competitive promoter regulation by the transcription factors, and experimentally validated the model predictions. Our results reveal that hepcidin cross-regulation primarily occurs by combinatorial transcription factor binding to the promoter, whereas signaling crosstalk is insignificant. We find that the presence of two BMP-responsive elements enhances the steepness of the promoter response towards the iron-sensing BMP signaling axis, which promotes iron homeostasis in vivo. IL6 co-stimulation reduces the promoter sensitivity towards the BMP signal, because the SMAD and STAT transcription factors compete for recruiting RNA polymerase to the transcription start site. This may explain why inflammatory signals disturb iron homeostasis in anemia of inflammation. Taken together, our results reveal why the iron homeostasis circuit is sensitive to perturbations implicated in disease. PMID:24391488

  13. Understanding multi-scale structural evolution in granular systems through gMEMS

    NASA Astrophysics Data System (ADS)

    Walker, David M.; Tordesillas, Antoinette

    2013-06-01

    We show how the rheological response of a material to applied loads can be systematically coded, analyzed and succinctly summarized, according to an individual grain's property (e.g. kinematics). Individual grains are considered as their own smart sensor akin to microelectromechanical systems (e.g. gyroscopes, accelerometers), each capable of recognizing their evolving role within self-organizing building block structures (e.g. contact cycles and force chains). A symbolic time series is used to represent their participation in such self-assembled building blocks and a complex network summarizing their interrelationship with other grains is constructed. In particular, relationships between grain time series are determined according to the information theory Hamming distance or the metric Euclidean distance. We then use topological distance to find network communities enabling groups of grains at remote physical metric distances in the material to share a classification. In essence grains with similar structural and functional roles at different scales are identified together. This taxonomy distills the dissipative structural rearrangements of grains down to its essential features and thus provides pointers for objective physics-based internal variable formalisms used in the construction of robust predictive continuum models.

  14. Multi-Scale Monitoring and Prediction of System Responses to Biostimulation

    SciTech Connect

    Hubbard, Susan; Williams, Ken; Steefel, Carl; Long, Phil; Kinsong Chen, Slater, Lee; Banfield, Jill

    2006-04-05

    To advance solutions needed for remediation of DOE contaminated sites, approaches are needed that can elucidate and predict reactions associated with coupled biological, geochemical, and hydrological processes over a variety of spatial scales and in heterogeneous environments. Our laboratory experimental experiments, which were conducted under controlled conditions, suggest that geophysical methods have the potential for elucidating system transformations that often occur during remediation, such as the generation of gases and precipitates. In this new ERSP project, we will Integrate hydrological, biogeochemical, and geophysical expertise and approaches to: (1) Explore the potential of geophysical methods for detecting changes in physical, chemical, and biological properties at the field scale; and (2) Explore the joint use of reactive transport modeling and geophysical monitoring information for improvements in both methods. A brief review of our previously-conducted laboratory results are given in Section II. Section III describes the approach for our new project, which will have both laboratory and field-scale components. The field scale component will be conducted at the Rifle, CO. site, which is described in Section IV.

  15. Multi-Scale Predictions of the Asian Monsoons in the NCEP Climate Forecast System

    NASA Astrophysics Data System (ADS)

    Yang, S.

    2013-12-01

    A comprehensive analysis of the major features of the Asian monsoon system in the NCEP Climate Forecast System version 2 (CFSv2) and predictions of the monsoon by the model has been conducted. The intraseasonal-to-interannual variations of both summer monsoon and winter monsoon, as well as the annual cycles of monsoon climate, are focused. Features of regional monsoons including the monsoon phenomena over South Asia, East Asia, and Southeast Asia are discussed. The quasi-biweekly oscillation over tropical Asia and the Mei-yu climate over East Asia are also investigated. Several aspects of monsoon features including the relationships between monsoon and ENSO (including different types of ENSO: eastern Pacific warming and central Pacific warming), extratropical effects, dependence on time leads (initial conditions), regional monsoon features, and comparison between CFSv2 and CFS version 1 (CFSv1) are particularly emphasized. Large-scale characteristics of the Asian summer monsoon including several major dynamical monsoon indices and their associated precipitation patterns can be predicted several months in advance. The skill of predictions of the monsoon originates mostly from the impact of ENSO. It is found that large predictability errors occur in first three lead months and they only change slightly as lead time increases. The large errors in the first three lead months are associated with the large errors in surface thermal condition and atmospheric circulation in the central and eastern Pacific and the African continent. In addition, the response of the summer monsoon to ENSO becomes stronger with increase in lead time. The CFSv2 successfully simulates several major features of the East Asian winter monsoon and its relationships with the Arctic Oscillation, the East Asian subtropical jet, the East Asian trough, the Siberian high, and the lower-tropospheric winds. Surprisingly, the upper-tropospheric winds over the middle-high latitudes can be better simulated

  16. Multiscale models for synthetic biology.

    PubMed

    Kaznessis, Yiannis N

    2009-01-01

    Reacting systems away from the thermodynamic limit cannot be accurately modeled with ordinary differential equations. These continuous-deterministic modeling formalisms, traditionally developed and used by chemical engineers can be distinctly false if the number of molecules of reacting chemical species is very small, or if reaction events are very rare. Then stochastic-discrete representations are appropriate. Importantly, in cases where in a network of reactions there are some parts that must be modeled discretely and stochastically, yet others can be modeled continuously and deterministically, the need for development of multiscale models emerges naturally. In computational synthetic biology, such cases arise often. In this work we present the development of multiscale models for synthetic biology applications, demonstrating accuracy, computational efficiency and utility.

  17. Development of Laboratory Testing Criteria for Evaluating Cementitious, Rapid-Setting Pavement Repair Materials

    DTIC Science & Technology

    2011-04-01

    ER D C/ G SL T R- 11 -1 3 Development of Laboratory Testing Criteria for Evaluating Cementitious, Rapid-Setting Pavement Repair...unlimited. ERDC/GSL TR-11-13 April 2011 Development of Laboratory Testing Criteria for Evaluating Cementitious, Rapid-Setting Pavement Repair...surface repairs in portland cement concrete (PCC) pavements that provide short set times, high early strengths, and durability to withstand heavy loads

  18. Cementitious Stabilization of Mixed Wastes with High Salt Loadings

    SciTech Connect

    Spence, R.D.; Burgess, M.W.; Fedorov, V.V.; Downing, D.J.

    1999-04-01

    Salt loadings approaching 50 wt % were tolerated in cementitious waste forms that still met leach and strength criteria, addressing a Technology Deficiency of low salt loadings previously identified by the Mixed Waste Focus Area. A statistical design quantified the effect of different stabilizing ingredients and salt loading on performance at lower loadings, allowing selection of the more effective ingredients for studying the higher salt loadings. In general, the final waste form needed to consist of 25 wt % of the dry stabilizing ingredients to meet the criteria used and 25 wt % water to form a workable paste, leaving 50 wt % for waste solids. The salt loading depends on the salt content of the waste solids but could be as high as 50 wt % if all the waste solids are salt.

  19. Cementitious Wasteforms for Immobilization of Low-Activity Radioactive Wastes

    SciTech Connect

    Wellman, Dawn M.; Bovaird, Chase C.; Parker, Kent E.; Mattigod, Shas V.; Clayton, Libby N.; Powers, Laura; Wood, Marcus I.; Cordova, Elsa A.; Davis, Aaron M.

    2009-10-29

    Solidification of low-activity wastes with cementitious materials is a widely accepted technique that contains and isolates waste from the hydrologic environment. The radionuclides I-129, Se-75, Tc-99, and U-238 are identified as long-term dose contributors. The anionic nature of these radionuclides in aqueous solutions allows them to readily leach into the subsurface environment. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages via mass flow and/or diffusion into the surrounding subsurface environment. Assessing the long-term performance of waste grouts for encasement of radionuclides requires understanding the: 1) speciation and interaction of the radionuclides within the concrete wasteform, 2) diffusion of radionuclide species when contacted with vadose zone porewater or groundwater under environmentally relevant conditions, and 3) long-term durability and weathering of concrete waste forms. An improved understanding of the interactions of long-lived radionuclides in cementitious matrices will improve predictions of the long-term fate of these sequestered contaminants. An integrated laboratory investigation has been conducted including a: 1) multifaceted spectroscopic investigation to interrogate the speciation and interaction of radionuclides within concrete wasteforms, 2) solubility tests to quantify the stability of solid phases identified as radionuclide-controlling phases, 3) quantify the diffusion of radionuclides from concrete wasteforms into surrounding subsurface sediment under realistic moisture contents (4%, 7%, and 15% by weight moisture content), 4) quantify the long-term durability of concrete waste forms as a function environmental parameters relevant to depository conditions, and 5) identify the formation of secondary phases or processes (microcracking) that influence radionuclide retention. Data obtained from this investigation provides valuable information for

  20. Quantifying rock's structural fabric: a multi-scale hierarchical approach to natural fracture systems and stochastic modelling

    NASA Astrophysics Data System (ADS)

    Hardebol, Nico; Bertotti, Giovanni; Weltje, Gert Jan

    2014-05-01

    We propose the description of fracture-fault systems in terms of a multi-scale hierarchical network. In most generic form, such arrangement is referred to as a structural fabric and applicable across the length scale spectrum. The statistical characterisation combines the fracture length and orientation distributions and intersection-termination relationships. The aim is a parameterised description of the network that serves as input in stochastic network simulations that should reproduce the essence of natural fracture networks and encompass its variability. The quality of the stochastically generated fabric is determined by comparison with deterministic descriptions on which the model parameterisation is based. Both the deterministic and stochastic derived fracture network description can serve as input in fluid flow or mechanical simulations that accounts explicitly for the discrete features and the response of the system can be compared. The deterministic description of our current study in the framework of tight gas reservoirs is obtained from coastal pavements that expose a horizontal slice through a fracture-fault network system in fine grained sediments in Yorkshire, UK. Fracture hierarchies have often been described at one observation scale as a two-tier hierarchy in terms of 1st order systematic joints and 2nd order cross-joints. New in our description is the bridging between km-sized faults with notable displacement down to sub-meter scale shear and opening mode fractures. This study utilized a drone to obtain cm-resolution imagery of pavements from ~30m altitude and the large coverage up to 1-km by flying at a ~80m. This unique set of images forms the basis for the digitizing of the fracture-fault pattern and helped determining the nested nature of the network as well as intersection and abutment relationships. Fracture sets were defined from the highest to lowest hierarchical order and probability density functions were defined for the length

  1. Multiscale Modeling in Computational Biomechanics: Determining Computational Priorities and Addressing Current Challenges

    SciTech Connect

    Tawhai, Merryn; Bischoff, Jeff; Einstein, Daniel R.; Erdemir, Ahmet; Guess, Trent; Reinbolt, Jeff

    2009-05-01

    Abstract In this article, we describe some current multiscale modeling issues in computational biomechanics from the perspective of the musculoskeletal and respiratory systems and mechanotransduction. First, we outline the necessity of multiscale simulations in these biological systems. Then we summarize challenges inherent to multiscale biomechanics modeling, regardless of the subdiscipline, followed by computational challenges that are system-specific. We discuss some of the current tools that have been utilized to aid research in multiscale mechanics simulations, and the priorities to further the field of multiscale biomechanics computation.

  2. Multiscale System Theory

    DTIC Science & Technology

    1990-02-21

    ac, 3 respectively, and the swTwl’s are matrix coefficients. In this writing we implicitly assume that all simplifications (2.17, 2.18, 2.19) have been...associate with S the following Hankel matrix : ’H(S)ij = SwTt where the monomials (w)i>0 are ordered according to the increasing degree with priority...such a basis, and set q Onk - where 0 denotes the Kronecker product, and the identity matrix I is of suitable dimension for eqn. (3.3) to be consistent

  3. Differential Geometry Based Multiscale Models

    PubMed Central

    Wei, Guo-Wei

    2010-01-01

    Large chemical and biological systems such as fuel cells, ion channels, molecular motors, and viruses are of great importance to the scientific community and public health. Typically, these complex systems in conjunction with their aquatic environment pose a fabulous challenge to theoretical description, simulation, and prediction. In this work, we propose a differential geometry based multiscale paradigm to model complex macromolecular systems, and to put macroscopic and microscopic descriptions on an equal footing. In our approach, the differential geometry theory of surfaces and geometric measure theory are employed as a natural means to couple the macroscopic continuum mechanical description of the aquatic environment with the microscopic discrete atom-istic description of the macromolecule. Multiscale free energy functionals, or multiscale action functionals are constructed as a unified framework to derive the governing equations for the dynamics of different scales and different descriptions. Two types of aqueous macromolecular complexes, ones that are near equilibrium and others that are far from equilibrium, are considered in our formulations. We show that generalized Navier–Stokes equations for the fluid dynamics, generalized Poisson equations or generalized Poisson–Boltzmann equations for electrostatic interactions, and Newton's equation for the molecular dynamics can be derived by the least action principle. These equations are coupled through the continuum-discrete interface whose dynamics is governed by potential driven geometric flows. Comparison is given to classical descriptions of the fluid and electrostatic interactions without geometric flow based micro-macro interfaces. The detailed balance of forces is emphasized in the present work. We further extend the proposed multiscale paradigm to micro-macro analysis of electrohydrodynamics, electrophoresis, fuel cells, and ion channels. We derive generalized Poisson–Nernst–Planck equations that

  4. Differential geometry based multiscale models.

    PubMed

    Wei, Guo-Wei

    2010-08-01

    Large chemical and biological systems such as fuel cells, ion channels, molecular motors, and viruses are of great importance to the scientific community and public health. Typically, these complex systems in conjunction with their aquatic environment pose a fabulous challenge to theoretical description, simulation, and prediction. In this work, we propose a differential geometry based multiscale paradigm to model complex macromolecular systems, and to put macroscopic and microscopic descriptions on an equal footing. In our approach, the differential geometry theory of surfaces and geometric measure theory are employed as a natural means to couple the macroscopic continuum mechanical description of the aquatic environment with the microscopic discrete atomistic description of the macromolecule. Multiscale free energy functionals, or multiscale action functionals are constructed as a unified framework to derive the governing equations for the dynamics of different scales and different descriptions. Two types of aqueous macromolecular complexes, ones that are near equilibrium and others that are far from equilibrium, are considered in our formulations. We show that generalized Navier-Stokes equations for the fluid dynamics, generalized Poisson equations or generalized Poisson-Boltzmann equations for electrostatic interactions, and Newton's equation for the molecular dynamics can be derived by the least action principle. These equations are coupled through the continuum-discrete interface whose dynamics is governed by potential driven geometric flows. Comparison is given to classical descriptions of the fluid and electrostatic interactions without geometric flow based micro-macro interfaces. The detailed balance of forces is emphasized in the present work. We further extend the proposed multiscale paradigm to micro-macro analysis of electrohydrodynamics, electrophoresis, fuel cells, and ion channels. We derive generalized Poisson-Nernst-Planck equations that are

  5. A multi-scale cardiovascular system model can account for the load-dependence of the end-systolic pressure-volume relationship

    PubMed Central

    2013-01-01

    Background The end-systolic pressure-volume relationship is often considered as a load-independent property of the heart and, for this reason, is widely used as an index of ventricular contractility. However, many criticisms have been expressed against this index and the underlying time-varying elastance theory: first, it does not consider the phenomena underlying contraction and second, the end-systolic pressure volume relationship has been experimentally shown to be load-dependent. Methods In place of the time-varying elastance theory, a microscopic model of sarcomere contraction is used to infer the pressure generated by the contraction of the left ventricle, considered as a spherical assembling of sarcomere units. The left ventricle model is inserted into a closed-loop model of the cardiovascular system. Finally, parameters of the modified cardiovascular system model are identified to reproduce the hemodynamics of a normal dog. Results Experiments that have proven the limitations of the time-varying elastance theory are reproduced with our model: (1) preload reductions, (2) afterload increases, (3) the same experiments with increased ventricular contractility, (4) isovolumic contractions and (5) flow-clamps. All experiments simulated with the model generate different end-systolic pressure-volume relationships, showing that this relationship is actually load-dependent. Furthermore, we show that the results of our simulations are in good agreement with experiments. Conclusions We implemented a multi-scale model of the cardiovascular system, in which ventricular contraction is described by a detailed sarcomere model. Using this model, we successfully reproduced a number of experiments that have shown the failing points of the time-varying elastance theory. In particular, the developed multi-scale model of the cardiovascular system can capture the load-dependence of the end-systolic pressure-volume relationship. PMID:23363818

  6. Multiscale model approach for magnetization dynamics simulations

    NASA Astrophysics Data System (ADS)

    De Lucia, Andrea; Krüger, Benjamin; Tretiakov, Oleg A.; Kläui, Mathias

    2016-11-01

    Simulations of magnetization dynamics in a multiscale environment enable the rapid evaluation of the Landau-Lifshitz-Gilbert equation in a mesoscopic sample with nanoscopic accuracy in areas where such accuracy is required. We have developed a multiscale magnetization dynamics simulation approach that can be applied to large systems with spin structures that vary locally on small length scales. To implement this, the conventional micromagnetic simulation framework has been expanded to include a multiscale solving routine. The software selectively simulates different regions of a ferromagnetic sample according to the spin structures located within in order to employ a suitable discretization and use either a micromagnetic or an atomistic model. To demonstrate the validity of the multiscale approach, we simulate the spin wave transmission across the regions simulated with the two different models and different discretizations. We find that the interface between the regions is fully transparent for spin waves with frequency lower than a certain threshold set by the coarse scale micromagnetic model with no noticeable attenuation due to the interface between the models. As a comparison to exact analytical theory, we show that in a system with a Dzyaloshinskii-Moriya interaction leading to spin spirals, the simulated multiscale result is in good quantitative agreement with the analytical calculation.

  7. REVIEW OF MECHANISTIC UNDERSTANDING AND MODELING AND UNCERTAINTY ANALYSIS METHODS FOR PREDICTING CEMENTITIOUS BARRIER PERFORMANCE

    SciTech Connect

    Langton, C.; Kosson, D.

    2009-11-30

    Cementitious barriers for nuclear applications are one of the primary controls for preventing or limiting radionuclide release into the environment. At the present time, performance and risk assessments do not fully incorporate the effectiveness of engineered barriers because the processes that influence performance are coupled and complicated. Better understanding the behavior of cementitious barriers is necessary to evaluate and improve the design of materials and structures used for radioactive waste containment, life extension of current nuclear facilities, and design of future nuclear facilities, including those needed for nuclear fuel storage and processing, nuclear power production and waste management. The focus of the Cementitious Barriers Partnership (CBP) literature review is to document the current level of knowledge with respect to: (1) mechanisms and processes that directly influence the performance of cementitious materials (2) methodologies for modeling the performance of these mechanisms and processes and (3) approaches to addressing and quantifying uncertainties associated with performance predictions. This will serve as an important reference document for the professional community responsible for the design and performance assessment of cementitious materials in nuclear applications. This review also provides a multi-disciplinary foundation for identification, research, development and demonstration of improvements in conceptual understanding, measurements and performance modeling that would be lead to significant reductions in the uncertainties and improved confidence in the estimating the long-term performance of cementitious materials in nuclear applications. This report identifies: (1) technology gaps that may be filled by the CBP project and also (2) information and computational methods that are in currently being applied in related fields but have not yet been incorporated into performance assessments of cementitious barriers. The various

  8. Expanded Large-Scale Forcing Properties Derived from the Multiscale Data Assimilation System and Its Application to Single-Column Models

    NASA Astrophysics Data System (ADS)

    Feng, S.; Li, Z.; Liu, Y.; Lin, W.; Toto, T.; Vogelmann, A. M.; Fridlind, A. M.

    2013-12-01

    We present an approach to derive large-scale forcing that is used to drive single-column models (SCMs) and cloud resolving models (CRMs)/large eddy simulation (LES) for evaluating fast physics parameterizations in climate models. The forcing fields are derived by use of a newly developed multi-scale data assimilation (MS-DA) system. This DA system is developed on top of the NCEP Gridpoint Statistical Interpolation (GSI) System and is implemented in the Weather Research and Forecasting (WRF) model at a cloud resolving resolution of 2 km. This approach has been applied to the generation of large scale forcing for a set of Intensive Operation Periods (IOPs) over the Atmospheric Radiation Measurement (ARM) Climate Research Facility's Southern Great Plains (SGP) site. The dense ARM in-situ observations and high-resolution satellite data effectively constrain the WRF model. The evaluation shows that the derived forcing displays accuracies comparable to the existing continuous forcing product and, overall, a better dynamic consistency with observed cloud and precipitation. One important application of this approach is to derive large-scale hydrometeor forcing and multiscale forcing, which is not provided in the existing continuous forcing product. It is shown that the hydrometeor forcing poses an appreciable impact on cloud and precipitation fields in the single-column model simulations. The large-scale forcing exhibits a significant dependency on domain-size that represents SCM grid-sizes. Subgrid processes often contribute a significant component to the large-scale forcing, and this contribution is sensitive to the grid-size and cloud-regime.

  9. Nanomechanics and Multiscale Modeling of Sustainable Concretes

    NASA Astrophysics Data System (ADS)

    Zanjani Zadeh, Vahid

    The work presented in this dissertation is aimed to implement and further develop the recent advances in material characterization for porous and heterogeneous materials and apply these advances to sustainable concretes. The studied sustainable concretes were concrete containing fly ash and slag, Kenaf fiber reinforced concrete, and lightweight aggregate concrete. All these cement-based materials can be categorized as sustainable concrete, by achieving concrete with high strength while reducing cement consumption. The nanoindentation technique was used to infer the nanomechanical properties of the active hydration phases in bulk cement paste. Moreover, the interfacial transition zone (ITZ) of lightweight aggregate, normal aggregate, and Kenaf fibers were investigated using nanoindentation and imagine techniques, despite difficulties regarding characterizing this region. Samples were also tested after exposure to high temperature to evaluate the damage mechanics of sustainable concretes. It has been shown that there is a direct correlation between the nature of the nanoscale structure of a cement-based material with its macroscopic properties. This was addressed in two steps in this dissertation: (i) Nanoscale characterization of sustainable cementitious materials to understand the different role of fly ash, slag, lightweight aggregate, and Kenaf fibers on nanoscale (ii) Link the nanoscale mechanical properties to macroscale ones with multiscale modeling. The grid indentation technique originally developed for normal concrete was extended to sustainable concretes with more complex microstructure. The relation between morphology of cement paste materials and submicron mechanical properties, indentation modulus, hardness, and dissipated energy is explained in detail. Extensive experimental and analytical approaches were focused on description of the materials' heterogeneous microstructure as function of their composition and physical phenomenon. Quantitative

  10. Nanomodification of Cementitious Materials: Fresh State and Early Age

    NASA Astrophysics Data System (ADS)

    Kawashima, Shiho

    Concrete is heterogeneous at all length scales and its microstructure evolves continuously over decades. Through the use of nanoparticles, it is possible to alter the microstructure of cementitious materials from within the first microsecond to control its rheological and eventual mechanical properties. The continued development of this technology hinges on adopting a materials science approach to achieve proper processing and measurement techniques, both of which are investigated in this study. Novel rheological methods are implemented to evaluate the fresh-state properties of cement pastes modified with nano-sized attapulgite clays. Previous studies have demonstrated that clays can reduce the lateral pressure exerted on formwork by self-consolidating concrete (SCC). It is hypothesized that this is tied to the influence of clays on two rheological properties of SCC: material cohesion and structural rebuilding. Therefore the effect of clays on adhesive properties is measured by the tack test and rate of rebuilding is evaluated by measuring relaxation time during creep. In addition, due to the complexity of cement rheology, i.e. simultaneous thixotropic rebuilding and hydration, the results are supplemented with a measure of the viscoelastic properties obtained through oscillatory shear rheometry. It is found that clays significantly increase cohesion and accelerate structural recovery of cement pastes. The results also indicate that the tack test is a suitable method for measuring the adhesive properties and structural evolution of cementitious materials in the fresh state. The potential of calcium carbonate (CaCO3) nanoparticles in improving the early-age properties of fly ash-cement pastes is investigated. The focus is on dispersing the CaCO3 nanoparticles to enhance their effect and limit the addition level necessary. The selected approach involves sonication in an aqueous medium and use of surfactant. Degree of dispersion and stability are quantitatively

  11. CEMENTITIOUS GROUT FOR CLOSING SRS HIGH LEVEL WASTE TANKS - #12315

    SciTech Connect

    Langton, C.; Burns, H.; Stefanko, D.

    2012-01-10

    In 1997, the first two United States Department of Energy (US DOE) high level waste tanks (Tanks 17-F and 20-F: Type IV, single shell tanks) were taken out of service (permanently closed) at the Savannah River Site (SRS). In 2012, the DOE plans to remove from service two additional Savannah River Site (SRS) Type IV high-level waste tanks, Tanks 18-F and 19-F. These tanks were constructed in the late 1950's and received low-heat waste and do not contain cooling coils. Operational closure of Tanks 18-F and 19-F is intended to be consistent with the applicable requirements of the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and will be performed in accordance with South Carolina Department of Health and Environmental Control (SCDHEC). The closure will physically stabilize two 4.92E+04 cubic meter (1.3 E+06 gallon) carbon steel tanks and isolate and stabilize any residual contaminants left in the tanks. The closure will also fill, physically stabilize and isolate ancillary equipment abandoned in the tanks. A Performance Assessment (PA) has been developed to assess the long-term fate and transport of residual contamination in the environment resulting from the operational closure of the F-Area Tank Farm (FTF) waste tanks. Next generation flowable, zero-bleed cementitious grouts were designed, tested, and specified for closing Tanks 18-F and 19-F and for filling the abandoned equipment. Fill requirements were developed for both the tank and equipment grouts. All grout formulations were required to be alkaline with a pH of 12.4 and chemically reduction potential (Eh) of -200 to -400 to stabilize selected potential contaminants of concern. This was achieved by including Portland cement and Grade 100 slag in the mixes, respectively. Ingredients and proportions of cementitious reagents were selected and adjusted, respectively, to support the mass placement strategy developed by closure

  12. Damage development, phase changes, transport properties, and freeze-thaw performance of cementitious materials exposed to chloride based salts

    NASA Astrophysics Data System (ADS)

    Farnam, Yaghoob

    Recently, there has been a dramatic increase in premature deterioration in concrete pavements and flat works that are exposed to chloride based salts. Chloride based salts can cause damage and deterioration in concrete due to the combination of factors which include: increased saturation, ice formation, salt crystallization, osmotic pressure, corrosion in steel reinforcement, and/or deleterious chemical reactions. This thesis discusses how chloride based salts interact with cementitious materials to (1) develop damage in concrete, (2) create new chemical phases in concrete, (3) alter transport properties of concrete, and (4) change the concrete freeze-thaw performance. A longitudinal guarded comparative calorimeter (LGCC) was developed to simultaneously measure heat flow, damage development, and phase changes in mortar samples exposed to sodium chloride (NaCl), calcium chloride (CaCl 2), and magnesium chloride (MgCl2) under thermal cycling. Acoustic emission and electrical resistivity measurements were used in conjunction with the LGCC to assess damage development and electrical response of mortar samples during cooling and heating. A low-temperature differential scanning calorimetry (LT-DSC) was used to evaluate the chemical interaction that occurs between the constituents of cementitious materials (i.e., pore solution, calcium hydroxide, and hydrated cement paste) and salts. Salts were observed to alter the classical phase diagram for a salt-water system which has been conventionally used to interpret the freeze-thaw behavior in concrete. An additional chemical phase change was observed for a concrete-salt-water system resulting in severe damage in cementitious materials. In a cementitious system exposed to NaCl, the chemical phase change occurs at a temperature range between -6 °C and 8 °C due to the presence of calcium sulfoaluminate phases in concrete. As a result, concrete exposed to NaCl can experience additional freeze-thaw cycles due to the chemical

  13. Monitoring the cementitious materials subjected to sulfate attack with optical fiber excitation Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Yue, Yanfei; Bai, Yun; Muhammed Basheer, P. A.; Boland, John J.; Wang, Jing Jing

    2013-10-01

    Formation of ettringite and gypsum from sulfate attack together with carbonation and chloride ingress have been considered as the most serious deterioration mechanisms of concrete structures. Although electrical resistance sensors and fiber optic chemical sensors could be used to monitor the latter two mechanisms on site, currently there is no system for monitoring the deterioration mechanisms of sulfate attack. In this paper, a preliminary study was carried out to investigate the feasibility of monitoring sulfate attack with optical fiber excitation Raman spectroscopy through characterizing the ettringite and gypsum formed in deteriorated cementitious materials under an optical fiber excitation + objective collection configuration. Bench-mounted Raman spectroscopy analysis was also conducted to validate the spectrum obtained from the fiber-objective configuration. The results showed that the expected Raman bands of ettringite and gypsum in the sulfate-attacked cement paste can be clearly identified by the optical fiber excitation Raman spectrometer and are in good agreement with those identified from bench-mounted Raman spectrometer. Therefore, based on these preliminary results, it is considered that there is a good potential for developing an optical fiber-based Raman system to monitor the deterioration mechanisms of concrete subjected to sulfate attack in the future.

  14. Deductive multiscale simulation using order parameters

    DOEpatents

    Ortoleva, Peter J.

    2017-05-16

    Illustrative embodiments of systems and methods for the deductive multiscale simulation of macromolecules are disclosed. In one illustrative embodiment, a deductive multiscale simulation method may include (i) constructing a set of order parameters that model one or more structural characteristics of a macromolecule, (ii) simulating an ensemble of atomistic configurations for the macromolecule using instantaneous values of the set of order parameters, (iii) simulating thermal-average forces and diffusivities for the ensemble of atomistic configurations, and (iv) evolving the set of order parameters via Langevin dynamics using the thermal-average forces and diffusivities.

  15. INTEGRATION OF THE BIOGENIC EMISSIONS INVENTORY SYSTEM (BEIS3) INTO THE COMMUNITY MULTISCALE AIR QUALITY MODELING SYSTEM

    EPA Science Inventory

    The importance of biogenic emissions for regional air quality modeling is generally recognized [Guenther et al., 2000]. Since the 1980s, biogenic emission estimates have been derived from algorithms such as the Biogenic Emissions Inventory System (BEIS) [Pierce et. al., 1998]....

  16. INTEGRATION OF THE BIOGENIC EMISSIONS INVENTORY SYSTEM (BEIS3) INTO THE COMMUNITY MULTISCALE AIR QUALITY MODELING SYSTEM

    EPA Science Inventory

    The importance of biogenic emissions for regional air quality modeling is generally recognized [Guenther et al., 2000]. Since the 1980s, biogenic emission estimates have been derived from algorithms such as the Biogenic Emissions Inventory System (BEIS) [Pierce et. al., 1998]....

  17. Nano-modification to improve the ductility of cementitious composites

    SciTech Connect

    Yeşilmen, Seda; Al-Najjar, Yazin; Balav, Mohammad Hatam; Şahmaran, Mustafa; Yıldırım, Gürkan; Lachemi, Mohamed

    2015-10-15

    Effect of nano-sized mineral additions on ductility of engineered cementitious composites (ECC) containing high volumes of fly ash was investigated at different hydration degrees. Various properties of ECC mixtures with different mineral additions were compared in terms of microstructural properties of matrix, fiber-matrix interface, and fiber surface to assess improvements in ductility. Microstructural characterization was made by measuring pore size distributions through mercury intrusion porosimetry (MIP). Hydration characteristics were assessed using thermogravimetric analysis/differential thermal analysis (TGA/DTA), and fiber-matrix interface and fiber surface characteristics were assessed using scanning electron microscopy (SEM) through a period of 90 days. Moreover, compressive and flexural strength developments were monitored for the same period. Test results confirmed that mineral additions could significantly improve both flexural strength and ductility of ECC, especially at early ages. Cheaper Nano-CaCO{sub 3} was more effective compared to nano-silica. However, the crystal structure of CaCO{sub 3} played a very important role in the range of expected improvements.

  18. Getters for improved technetium containment in cementitious waste forms.

    PubMed

    Asmussen, R Matthew; Pearce, Carolyn I; Miller, Brian W; Lawter, Amanda R; Neeway, James J; Lukens, Wayne W; Bowden, Mark E; Miller, Micah A; Buck, Edgar C; Serne, R Jeffery; Qafoku, Nikolla P

    2018-01-05

    A cementitious waste form, Cast Stone, is a possible candidate technology for the immobilization of low activity nuclear waste (LAW) at the Hanford site. This work focuses on the addition of getter materials to Cast Stone that can sequester Tc from the LAW, and in turn, lower Tc release from the Cast Stone. Two getters which produce different products upon sequestering Tc from LAW were tested: Sn(II) apatite (Sn-A) that removes Tc as a Tc(IV)-oxide and potassium metal sulfide (KMS-2) that removes Tc as a Tc(IV)-sulfide species, allowing for a comparison of stability of the form of Tc upon entering the waste form. The Cast Stone with KMS-2 getter had the best performance with addition equivalent to ∼0.08wt% of the total waste form mass. The observed diffusion (Dobs) of Tc decreased from 4.6±0.2×10(-12)cm(2)/s for Cast Stone that did not contain a getter to 5.4±0.4×10(-13)cm(2)/s for KMS-2 containing Cast Stone. It was found that Tc-sulfide species are more stable against re-oxidation within getter containing Cast Stone compared with Tc-oxide and is the origin of the decrease in Tc Dobs when using the KMS-2. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Mesoscale Fracture Analysis of Multiphase Cementitious Composites Using Peridynamics.

    PubMed

    Yaghoobi, Amin; Chorzepa, Mi G; Kim, S Sonny; A, Stephan

    2017-02-10

    Concrete is a complex heterogeneous material, and thus, it is important to develop numerical modeling methods to enhance the prediction accuracy of the fracture mechanism. In this study, a two-dimensional mesoscale model is developed using a non-ordinary state-based peridynamic (NOSBPD) method. Fracture in a concrete cube specimen subjected to pure tension is studied. The presence of heterogeneous materials consisting of coarse aggregates, interfacial transition zones, air voids and cementitious matrix is characterized as particle points in a two-dimensional mesoscale model. Coarse aggregates and voids are generated using uniform probability distributions, while a statistical study is provided to comprise the effect of random distributions of constituent materials. In obtaining the steady-state response, an incremental and iterativesolverisadopted for the dynamic relaxation method. Load-displacement curves and damage patterns are compared with available experimental and finite element analysis (FEA) results.Although the proposed model uses much simpler material damage models and discretization schemes, the load-displacementcurvesshownodifferencefromtheFEAresults. Furthermore,nomeshrefinement is necessary, as fracture is inherently characterized by bond breakages. Finally, a sensitivity study is conducted to understand the effect of aggregate volume fraction and porosity on the load capacity of the proposed mesoscale model.

  20. DEMONSTRATION OF LEACHXS/ORCHESTRA CAPABILITIES BY SIMULATING CONSTITUENT RELEASE FROM A CEMENTITIOUS WASTE FORM IN A REINFORCED CONCRETE VAULT

    SciTech Connect

    Langton, C.; Meeussen, J.; Sloot, H.

    2010-03-31

    The objective of the work described in this report is to demonstrate the capabilities of the current version of LeachXS{trademark}/ORCHESTRA for simulating chemical behavior and constituent release processes in a range of applications that are relevant to the CBP. This report illustrates the use of LeachXS{trademark}/ORCHESTRA for the following applications: (1) Comparing model and experimental results for leaching tests for a range of cementitious materials including cement mortars, grout, stabilized waste, and concrete. The leaching test data includes liquid-solid partitioning as a function of pH and release rates based on laboratory column, monolith, and field testing. (2) Modeling chemical speciation of constituents in cementitious materials, including liquid-solid partitioning and release rates. (3) Evaluating uncertainty in model predictions based on uncertainty in underlying composition, thermodynamic, and transport characteristics. (4) Generating predominance diagrams to evaluate predicted chemical changes as a result of material aging using the example of exposure to atmospheric conditions. (5) Modeling coupled geochemical speciation and diffusion in a three layer system consisting of a layer of Saltstone, a concrete barrier, and a layer of soil in contact with air. The simulations show developing concentration fronts over a time period of 1000 years. (6) Modeling sulfate attack and cracking due to ettringite formation. A detailed example for this case is provided in a separate article by the authors (Sarkar et al. 2010). Finally, based on the computed results, the sensitive input parameters for this type of modeling are identified and discussed. The chemical speciation behavior of substances is calculated for a batch system and also in combination with transport and within a three layer system. This includes release from a barrier to the surrounding soil as a function of time. As input for the simulations, the physical and chemical properties of the

  1. Cementitious encapsulation of waste materials and/or contaminated soils containing heavy metals, to render them immobile

    SciTech Connect

    Stark, J.N.

    1994-01-04

    The present invention relates to the cementitious encapsulation of waste materials and/or contaminated soils containing heavy metals, to render them immobile, and particularly to the immobilization of metals, in regulated amounts, in the wastes. A waste product comprising the metals is provided. A mixture is prepared comprising the wastes and/or contaminated soils containing heavy metals, water, and a cementitious composition. The cementitious composition comprises magnesium oxide and magnesium chloride in proportions effective to produce, with the water, a magnesium oxychloride cement. The cementitious composition is present in an amount which, on setting, is effective to immobilize the metals in the waste and/or contaminated soils. The mixture of waste and/or contaminated soils and cementitious composition is introduced to a disposition site, and allowed to set and harden at the site. The present invention is particularly useful for the remedial treatment of landfill sites. No Drawings

  2. Thermally conductive cementitious grouts for geothermal heat pumps. Progress report FY 1998

    SciTech Connect

    Allan, M.L.; Philippacopoulos, A.J.

    1998-11-01

    Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98. The developed thermally conductive grout consists of cement, water, a particular grade of silica sand, superplasticizer and a small amount of bentonite. While the primary function of the grout is to facilitate heat transfer between the U-loop and surrounding formation, it is also essential that the grout act as an effective borehole sealant. Two types of permeability (hydraulic conductivity) tests was conducted to evaluate the sealing performance of the cement-sand grout. Additional properties of the proposed grout that were investigated include bleeding, shrinkage, bond strength, freeze-thaw durability, compressive, flexural and tensile strengths, elastic modulus, Poisson`s ratio and ultrasonic pulse velocity.

  3. Characteristics of high temperature cementitious lost-circulation control materials for geothermal wells

    SciTech Connect

    Sugama, T.; Kukacka, L.E.; Galen, B.G.; Milestone, N.B.

    1986-01-01

    Materials systems have been formulated for the in situ conversion of water-based bentonite drilling fluids into cementitious lost-circulation control materials (CLCM) for use in geothermal wells at temperatures up to 300/sup 0/C. The formulations consist of a cement hardener, a borax admixture, and a fiber glass bridging material which are added to the bentonite fluids. Evaluations of the properties of the slurry and the cured CLCMS revealed that the ions supplied by dissociation of the borax in the CLCM slurry acted to suppress the bentonite hydration and retarded the hardening rate of the cement at elevated temperatures. The CaO-SiO/sub 2/-H/sub 2/O (C-S-H) phases formed during curing of the CLCM play essential roles in improving the quality of the hardened CLCMs. It was observed that xonotlite-truscottite transformation resulted in strength reductions and increased water permeability. The plugging ability of fiber glass depends on the conentration and fiber size. The silicate ions dissolved by hot alkaline disintegration of the fiber glass were chemisorbed with Ca/sup 2 +/ ions from the cement and led to the precipitation of C-S-H compounds on the fiber surfaces, which improved bond strength at the matrix-fiber interfaces.

  4. Multiscale information modelling for heart morphogenesis

    NASA Astrophysics Data System (ADS)

    Abdulla, T.; Imms, R.; Schleich, J. M.; Summers, R.

    2010-07-01

    Science is made feasible by the adoption of common systems of units. As research has become more data intensive, especially in the biomedical domain, it requires the adoption of a common system of information models, to make explicit the relationship between one set of data and another, regardless of format. This is being realised through the OBO Foundry to develop a suite of reference ontologies, and NCBO Bioportal to provide services to integrate biomedical resources and functionality to visualise and create mappings between ontology terms. Biomedical experts tend to be focused at one level of spatial scale, be it biochemistry, cell biology, or anatomy. Likewise, the ontologies they use tend to be focused at a particular level of scale. There is increasing interest in a multiscale systems approach, which attempts to integrate between different levels of scale to gain understanding of emergent effects. This is a return to physiological medicine with a computational emphasis, exemplified by the worldwide Physiome initiative, and the European Union funded Network of Excellence in the Virtual Physiological Human. However, little work has been done on how information modelling itself may be tailored to a multiscale systems approach. We demonstrate how this can be done for the complex process of heart morphogenesis, which requires multiscale understanding in both time and spatial domains. Such an effort enables the integration of multiscale metrology.

  5. A uniformly accurate multiscale time integrator spectral method for the Klein-Gordon-Zakharov system in the high-plasma-frequency limit regime

    NASA Astrophysics Data System (ADS)

    Bao, Weizhu; Zhao, Xiaofei

    2016-12-01

    A multiscale time integrator sine pseudospectral (MTI-SP) method is presented for discretizing the Klein-Gordon-Zakharov (KGZ) system with a dimensionless parameter 0 < ε ≤ 1, which is inversely proportional to the plasma frequency. In the high-plasma-frequency limit regime, i.e. 0 < ε ≪ 1, the solution of the KGZ system propagates waves with amplitude at O (1) and wavelength at O (ε2) in time and O (1) in space, which causes significantly numerical burdens due to the high oscillation in time. The main idea of the numerical method is to carry out a multiscale decomposition by frequency (MDF) to the electric field component of the solution at each time step and then apply the sine pseudospectral discretization for spatial derivatives followed by using the exponential wave integrator in phase space for integrating the MDF and the equation of the ion density component. The method is explicit and easy to be implemented. Extensive numerical results show that the MTI-SP method converges uniformly and optimally in space with exponential convergence rate if the solution is smooth, and uniformly in time with linear convergence rate at O (τ) for ε ∈ (0 , 1 ] with τ time step size and optimally with quadratic convergence rate at O (τ2) in the regime when either ε = O (1) or 0 < ε ≤ τ. Thus the meshing strategy requirement (or ε-scalability) of the MTI-SP for the KGZ system in the high-plasma-frequency limit regime is τ = O (1) and h = O (1) for 0 < ε ≪ 1, which is significantly better than classical methods in the literatures. Finally, we apply the MTI-SP method to study the convergence rates of the KGZ system to its limiting models in the high-plasma-frequency limit and the interactions of bright solitons of the KGZ system, and to identify certain parameter regimes that the solution of the KGZ system will be blow-up in one dimension.

  6. Development of Semantic Description for Multiscale Models of Thermo-Mechanical Treatment of Metal Alloys

    NASA Astrophysics Data System (ADS)

    Macioł, Piotr; Regulski, Krzysztof

    2016-08-01

    We present a process of semantic meta-model development for data management in an adaptable multiscale modeling framework. The main problems in ontology design are discussed, and a solution achieved as a result of the research is presented. The main concepts concerning the application and data management background for multiscale modeling were derived from the AM3 approach—object-oriented Agile multiscale modeling methodology. The ontological description of multiscale models enables validation of semantic correctness of data interchange between submodels. We also present a possibility of using the ontological model as a supervisor in conjunction with a multiscale model controller and a knowledge base system. Multiscale modeling formal ontology (MMFO), designed for describing multiscale models' data and structures, is presented. A need for applying meta-ontology in the MMFO development process is discussed. Examples of MMFO application in describing thermo-mechanical treatment of metal alloys are discussed. Present and future applications of MMFO are described.

  7. CEMENTITIOUS BARRIERS MODELING FOR PERFORMANCE ASSESSMENTS OF SHALLOW LAND BURIAL OF LOW LEVEL RADIOACTIVE WASTE - 9243

    SciTech Connect

    Taylor, G

    2009-01-09

    The Cementitious Barriers Partnership (CBP) was created to develop predictive capabilities for the aging of cementitious barriers over long timeframes. The CBP is a multi-agency, multi-national consortium working under a U.S. Department of Energy (DOE) Environmental Management (EM-21) funded Cooperative Research and Development Agreement (CRADA) with the Savannah River National Laboratory (SRNL) as the lead laboratory. Members of the CBP are SRNL, Vanderbilt University, the U.S. Nuclear Regulatory Commission (USNRC), National Institute of Standards and Technology (NIST), SIMCO Technologies, Inc. (Canada), and the Energy Research Centre of the Netherlands (ECN). A first step in developing advanced tools is to determine the current state-of-the-art. A review has been undertaken to assess the treatment of cementitious barriers in Performance Assessments (PA). Representatives of US DOE sites which have PAs for their low level waste disposal facilities were contacted. These sites are the Idaho National Laboratory, Oak Ridge National Laboratory, Los Alamos National Laboratory, Nevada Test Site, and Hanford. Several of the more arid sites did not employ cementitious barriers. Of those sites which do employ cementitious barriers, a wide range of treatment of the barriers in a PA was present. Some sites used conservative, simplistic models that even though conservative still showed compliance with disposal limits. Other sites used much more detailed models to demonstrate compliance. These more detailed models tend to be correlation-based rather than mechanistically-based. With the US DOE's Low Level Waste Disposal Federal Review Group (LFRG) moving towards embracing a risk-based, best estimate with an uncertainties type of analysis, the conservative treatment of the cementitious barriers seems to be obviated. The CBP is creating a tool that adheres to the LFRG chairman's paradigm of continuous improvement.

  8. Cementitious building material incorporating end-capped polyethylene glycol as a phase change material

    DOEpatents

    Salyer, Ival O.; Griffen, Charles W.

    1986-01-01

    A cementitious composition comprising a cementitious material and polyethylene glycol or end-capped polyethylene glycol as a phase change material, said polyethylene glycol and said end-capped polyethylene glycol having a molecular weight greater than about 400 and a heat of fusion greater than about 30 cal/g; the compositions are useful in making pre-formed building materials such as concrete blocks, brick, dry wall and the like or in making poured structures such as walls or floor pads; the glycols can be encapsulated to reduce their tendency to retard set.

  9. Preliminary study on improvement of cementitious grout thermal conductivity for geothermal heat pump applications

    SciTech Connect

    Allan, M.L.

    1996-06-01

    Preliminary studies were preformed to determine whether thermal conductivity of cementitious grouts used to backfill heat exchanger loops for geothermal heat pumps could be improved, thus improving efficiency. Grouts containing selected additives were compares with conventional bentonite and cement grouts. Significant enhancement of grout alumina grit, steel fibers, and silicon carbide increased the thermal conductivity when compared to unfilled, high solids bentonite grouts and conventional cement grouts. Furthermore, the developed grouts retained high thermal conductivity in the dry state, where as conventional bentonite and cement grouts tend to act as insulators if moisture is lost. The cementitious grouts studied can be mixed and placed using conventional grouting equipment.

  10. Method for characterization of the rate of movement of an oxidation front in cementitious materials

    DOEpatents

    Almond, Philip M.; Langton, Christine A.; Stefanko, David B.

    2016-03-01

    Disclosed are methods for determining the redox condition of cementitious materials. The methods are leaching methods that utilize a redox active transition metal indicator that is present in the cementitious material and exhibits variable solubility depending upon the oxidation state of the indicator. When the leaching process is carried out under anaerobic conditions, the presence or absence of the indicator in the leachate can be utilized to determine the redox condition of and location of the oxidation front in the material that has been subjected to the leaching process.

  11. The evolution of clay rock/cement interfaces in a cementitious repository for low- and intermediate level radioactive waste

    NASA Astrophysics Data System (ADS)

    Kosakowski, Georg; Berner, Urs

    In Switzerland, deep geological storage in clay rich host rocks is the preferred option for low- and intermediate-level radioactive waste. For these waste types cementitious materials are used for tunnel support and backfill, waste containers and waste matrixes. The different geochemical characteristics of clay and cementitious materials may induce mineralogical and pore water changes which might affect the barrier functionality of host rocks and concretes. We present numerical reactive transport calculations that systematically compare the geochemical evolution at cement/clay interfaces for the proposed host rocks in Switzerland for different transport scenarios. We developed a consistent set of thermodynamic data, simultaneously valid for cementitious (concrete) and clay materials. With our setup we successfully reproduced mineralogies, water contents and pore water compositions of the proposed host rocks and of a reference concrete. Our calculations show that the effects of geochemical gradients between concrete and clay materials are very similar for all investigated host rocks. The mineralogical changes at material interfaces are restricted to narrow zones for all host rocks. The extent of strong pH increase in the host rocks is limited, although a slight increase of pH over greater distances seems possible in advective transport scenarios. Our diffusive and partially also the advective calculations show massive porosity changes due to precipitation/dissolution of mineral phases near the interface, in line with many other reported transport calculations on cement/clay interactions. For all investigated transport scenarios the degradation of concrete materials in emplacement caverns due to diffusive and advective transport of clay pore water into the caverns is limited to narrow zones. A specific effort has been made to improve the geochemical setup and the extensive use of solid solution phases demonstrated the successful application of a thermodynamically

  12. Multi-scale constraints of sediment source to sink systems in frontier basins: a forward stratigraphic modeling case study of the Levant region

    NASA Astrophysics Data System (ADS)

    Hawie, Nicolas; Deschamps, Remy; Granjeon, Didier; Nader, Fadi-Henri; Gorini, Christian; Müller, Carla; Montadert, Lucien; Baudin, François

    2015-04-01

    Recent scientific work underlined the presence of a thick Cenozoic infill in the Levant Basin reaching up to 12 km. Interestingly; restricted sedimentation was observed along the Levant margin in the Cenozoic. Since the Late Eocene successive regional geodynamic events affecting Afro-Arabia and Eurasia (collision and strike slip deformation)induced fast marginal uplifts. The initiation of local and long-lived regional drainage systems in the Oligo-Miocene period (e.g. Lebanon versus Nile) provoked a change in the depositional pattern along the Levant margin and basin. A shift from carbonate dominated environments into clastic rich systems has been observed. Through this communication we explore the importance of multi-scale constraints (i.e.,seismic, well and field data) in the quantification of the subsidence history, sediment transport and deposition of a Middle-Upper Miocene "multi-source" to sink system along the northernLevant frontier region. We prove through a comprehensive forward stratigraphic modeling workflow that the contribution to the infill of the northern Levant Basin (offshore Lebanon) is split in between proximal and more distal clastic sources as well as in situ carbonate/hemipelagic deposition. In a wider perspective this work falls under the umbrella of multi-disciplinary source to sink studies that investigate the impact of geodynamic events on basin/margin architectural evolutions, consequent sedimentary infill and thus on petroleum systems assessment.

  13. An Analysis Platform for Multiscale Hydrogeologic Modeling with Emphasis on Hybrid Multiscale Methods

    SciTech Connect

    Scheibe, Timothy D.; Murphy, Ellyn M.; Chen, Xingyuan; Rice, Amy K.; Carroll, Kenneth C.; Palmer, Bruce J.; Tartakovsky, Alexandre M.; Battiato, Ilenia; Wood, Brian D.

    2015-01-01

    One of the most significant challenges facing hydrogeologic modelers is the disparity between those spatial and temporal scales at which fundamental flow, transport and reaction processes can best be understood and quantified (e.g., microscopic to pore scales, seconds to days) and those at which practical model predictions are needed (e.g., plume to aquifer scales, years to centuries). While the multiscale nature of hydrogeologic problems is widely recognized, technological limitations in computational and characterization restrict most practical modeling efforts to fairly coarse representations of heterogeneous properties and processes. For some modern problems, the necessary level of simplification is such that model parameters may lose physical meaning and model predictive ability is questionable for any conditions other than those to which the model was calibrated. Recently, there has been broad interest across a wide range of scientific and engineering disciplines in simulation approaches that more rigorously account for the multiscale nature of systems of interest. In this paper, we review a number of such approaches and propose a classification scheme for defining different types of multiscale simulation methods and those classes of problems to which they are most applicable. Our classification scheme is presented in terms of a flow chart (Multiscale Analysis Platform or MAP), and defines several different motifs of multiscale simulation. Within each motif, the member methods are reviewed and example applications are discussed. We focus attention on hybrid multiscale methods, in which two or more models with different physics described at fundamentally different scales are directly coupled within a single simulation. Very recently these methods have begun to be applied to groundwater flow and transport simulations, and we discuss these applications in the context of our classification scheme. As computational and characterization capabilities continue to

  14. SCM Paste Samples Exposed To Aggressive Solutions. Cementitious Barriers Partnership

    SciTech Connect

    Foster, T.

    2014-12-01

    This report summarizes experimental work performed by SIMCO Technologies Inc. (SIMCO) as part of the Cementitious Barriers Partnership (CBP) project. The test series followed an experimental program dedicated to the study of ordinary Portland cement (OPC) hydrated cement pastes exposed to aggressive solutions. In the present study, the scope is extended to hydrated cement pastes incorporating supplementary cementitious materials (SCM) such as fly ash and ground granulated blast furnace slag (GGBFS). Also, the range of aggressive contact solutions was expanded. The experimental program aimed at testing aggressive contact solutions that more closely mimic the chemical composition of saltstone pore solution. Five different solutions, some of which incorporated high levels of carbonate and nitrate, were placed in contact with four different hydrated cement paste mixes. In all solutions, 150 mmol/L of SO42– (14 400 ppm) were present. The solutions included different pH conditions and different sodium content. Two paste mixes were equivalent to Vault 1/4 and Vault 2 concrete mixes used at SRS in storage structures. Two additional paste mixes, cast at the same water-to-cement ratio and using the same cements but without SCMs, were also tested. The damage evolution in samples was monitored using ultrasonic pulse velocity (UPV) and mass measurements. After three and twelve months of exposure conditions, samples were taken out of solution containers and analyzed to perform migration tests and porosity measurements. Globally, results were in line with the previous study and confirmed that high pH may limit the formation of some deleterious phases like gypsum. In this case, ettringite may form but is not necessarily associated with damage. However, the high concentration of sodium may be associated with the formation of an AFm-like mineral called U-phase. The most significant evidences of damage were all associated with the Vault 2 paste analog. This

  15. Timing of Getter Material Addition in Cementitious Wasteforms

    NASA Astrophysics Data System (ADS)

    Lawter, A.; Qafoku, N. P.; Asmussen, M.; Neeway, J.; Smith, G. L.

    2015-12-01

    A cementitious waste form, Cast Stone, is being evaluated as a possible supplemental immobilization technology for the Hanford sites's low activity waste (LAW), which contains radioactive 99Tc and 129I, as part of the tank waste cleanup mission. Cast Stone is made of a dry blend 47% blast furnace slag, 45% fly ash, and 8% ordinary Portland cement, mixed with a low-activity waste (LAW). To improve the retention of Tc and/or I in Cast Stone, materials with a high affinity for Tc and/or I, termed "getters," can be added to provide a stable domain for the radionuclides of concern. Previous testing conducted with a variety of getters has identified Tin(II)-Apatite and Silver Exchanged Zeolite as promising candidates for Tc and I, respectively. Investigation into the sequence in which getters are added to Cast Stone was performed following two methods: 1) adding getters to the Cast Stone dry blend, and then mixing with liquid waste, and 2) adding getters to the liquid waste first, followed by addition of the Cast Stone dry blend. Cast Stone monolith samples were prepared with each method and leach tests, following EPA method 1315, were conducted in either distilled water or simulated vadose zone porewater for a period of up to 63 days. The leachate was analyzed for Tc, I, Na, NO3-, NO2- and Cr with ICP-MS, ICP-OES and ion chromatography and the results indicated that the Cast Stone with getter addition in the dry blend mix (method 1) has lower rates of Tc and I leaching. The mechanisms of radionuclide release from the Cast Stone were also investigated with a variety of solid phase characterization techniques of the monoliths before and after leaching, such as XRD, SEM/EDS, TEM/SAED and other spectroscopic techniques.

  16. Bond strength of cementitious borehole plugs in welded tuff

    SciTech Connect

    Akgun, H.; Daemen, J.J.K.

    1991-02-01

    Axial loads on plugs or seals in an underground repository due to gas, water pressures and temperature changes induced subsequent to waste and plug emplacement lead to shear stresses at the plug/rock contact. Therefore, the bond between the plug and rock is a critical element for the design and effectiveness of plugs in boreholes, shafts or tunnels. This study includes a systematic investigation of the bond strength of cementitious borehole plugs in welded tuff. Analytical and numerical analysis of borehole plug-rock stress transfer mechanics is performed. The interface strength and deformation are studied as a function of Young`s modulus ratio of plug and rock, plug length and rock cylinder outside-to-inside radius ratio. The tensile stresses in and near an axially loaded plug are analyzed. The frictional interface strength of an axially loaded borehole plug, the effect of axial stress and lateral external stress, and thermal effects are also analyzed. Implications for plug design are discussed. The main conclusion is a strong recommendation to design friction plugs in shafts, drifts, tunnels or boreholes with a minimum length to diameter ratio of four. Such a geometrical design will reduce tensile stresses in the plug and in the host rock to a level which should minimize the risk of long-term deterioration caused by excessive tensile stresses. Push-out tests have been used to determine the bond strength by applying an axial load to cement plugs emplaced in boreholes in welded tuff cylinders. A total of 130 push-out tests have been performed as a function of borehole size, plug length, temperature, and degree of saturation of the host tuff. The use of four different borehole radii enables evaluation of size effects. 119 refs., 42 figs., 20 tabs.

  17. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

    SciTech Connect

    Jackson, Marie D.; Landis, Eric N.; Brune, Philip F.; Vitti, Massimo; Chen, Heng; Li, Qinfei; Kunz, Martin; Wenk, Hans -Rudolf; Monteiro, Paulo J. M.; Ingraffea, Anthony R.

    2014-12-15

    The pyroclastic aggregate concrete of Trajan’s Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime–volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium–aluminum-silicate–hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈ 0.8–0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900 year old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45–0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale.

  18. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar.

    PubMed

    Jackson, Marie D; Landis, Eric N; Brune, Philip F; Vitti, Massimo; Chen, Heng; Li, Qinfei; Kunz, Martin; Wenk, Hans-Rudolf; Monteiro, Paulo J M; Ingraffea, Anthony R

    2014-12-30

    The pyroclastic aggregate concrete of Trajan's Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime-volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium-aluminum-silicate-hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈ 0.8-0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥ 90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900-y-old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45-0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale.

  19. Waste E-glass particles used in cementitious mixtures

    SciTech Connect

    Chen, C.H.; Huang, R. . E-mail: ranhuang@mail.ntou.edu.tw; Wu, J.K.; Yang, C.C.

    2006-03-15

    The properties of concretes containing various waste E-glass particle contents were investigated in this study. Waste E-glass particles were obtained from electronic grade glass yarn scrap by grinding to small particle size. The size distribution of cylindrical glass particle was from 38 to 300 {mu}m and about 40% of E-glass particle was less than 150 {mu}m. The E-glass mainly consists of SiO{sub 2}, Al{sub 2}O{sub 3}, Ca O and MgO, and is indicated as amorphous by X-ray diffraction (XRD) technique. Compressive strength and resistance of sulfate attack and chloride ion penetration were significantly improved by utilizing proper amount of waste E-glass in concrete. The compressive strength of specimen with 40 wt.% E-glass content was 17%, 27% and 43% higher than that of control specimen at age of 28, 91 and 365 days, respectively. E-glass can be used in concrete as cementitious material as well as inert filler, which depending upon the particle size, and the dividing size appears to be 75 {mu}m. The workability decreased as the glass content increased due to reduction of fineness modulus, and the addition of high-range water reducers was needed to obtain a uniform mix. Little difference was observed in ASR testing results between control and E-glass specimens. Based on the properties of hardened concrete, optimum E-glass content was found to be 40-50 wt.%.

  20. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

    DOE PAGES

    Jackson, Marie D.; Landis, Eric N.; Brune, Philip F.; ...

    2014-12-15

    The pyroclastic aggregate concrete of Trajan’s Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime–volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium–aluminum-silicate–hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈more » 0.8–0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900 year old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45–0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale.« less

  1. Design of engineered cementitious composites for ductile seismic resistant elements

    NASA Astrophysics Data System (ADS)

    Kanda, Tetsushi

    This dissertation focuses on designing Engineered Cementitious Composite (ECC) to achieve high performance seismic resistant elements. To attain this goal, three major tasks have been accomplished. Task 1 aims at achieving new ECCs involving low cost fiber, which often involve fiber rupture in crack bridging, thus named as "Fiber Rupture Type ECC". Achieving the new ECC requires a new practical and comprehensive composite design theory. For this theory, single fiber behavior was first investigated. Specifically, fiber rupture in composite and chemical bond in fiber/matrix interface were experimentally examined and mathematically modeled. Then this model for single fiber behavior was implemented into a proposed bridging law, a theoretical model for relationship between fiber bridging stress of composite and Crack Opening Displacement (COD). This new bridging law was finally employed to establish a new composite design theory. Task 2 was initiated to facilitate structural interpretation of ECC's material behavior investigated in Task 1. For this purpose, uniaxial tensile behavior, one of the most important ECC's properties, was theoretically characterized with stress-strain relation from micromechanics view point. As a result, a theory is proposed to express ECC's tensile stress-strain relation in terms of micromechanics parameters of composites, such as bond strengths. Task 3 primarily demonstrates an integrated design scheme for ductile seismic elements that covers from micromechanics in single fiber level to structural design tool, such as with non-linear FEM analysis. The significance of this design scheme is that the influences of ECC's microstructure on element's structural performance is quantitatively captured. This means that a powerful tool is obtained for tailoring constitutive micromechanics parameters in order to maximize structural performance of elements. While the tool is still preliminary, completing this tool in future studies will enable one to

  2. Mechanisms of cementitious material deterioration in biogas digester.

    PubMed

    Voegel, C; Bertron, A; Erable, B

    2016-11-15

    Digesters produce biogas from organic wastes through anaerobic digestion processes. These digesters, often made of concrete, suffer severe premature deterioration caused mainly by the presence of fermentative microorganisms producing metabolites that are aggressive towards cementitious materials. To clarify the degradation mechanisms in an anaerobic digestion medium, ordinary Portland cement paste specimens were immersed in the liquid fraction of a running, lab-scale digester for 4weeks. The anaerobic digestion medium was a mixture of a biowaste substrate and sludge from municipal wastewater treatment plant used as a source of anaerobic bacteria. The chemical characteristics of the anaerobic digestion liquid phase were monitored over time using a pH metre, high performance liquid chromatography (HPLC) and ion chromatography (HPIC). An initial critical period of low pH in the bioreactors was observed before the pH stabilized around 8. Acetic, propionic and butyric acids were produced during the digestion with a maximum total organic acid concentration of 50mmolL(-1). The maximum ammonium content of the liquid phase was 40mmolL(-1), which was about seven times the upper limit of the highly aggressive chemical environment class (XA3) as defined by the European standard for the specification of concrete design in chemically aggressive environments (EN 206). The changes in the mineralogical, microstructural and chemical characteristics of the cement pastes exposed to the solid and liquid phase of the digesters were analysed at the end of the immersion period by X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDS) and electron-probe micro-analysis (EPMA). A 700-μm thick altered layer was identified in the cement paste specimens. The main biodeterioration patterns in the bioreactors' solid/liquid phase were calcium leaching and carbonation of the cement matrix.

  3. Mechanical resilience and cementitious processes in Imperial Roman architectural mortar

    PubMed Central

    Landis, Eric N.; Brune, Philip F.; Vitti, Massimo; Chen, Heng; Li, Qinfei; Kunz, Martin; Wenk, Hans-Rudolf; Monteiro, Paulo J. M.; Ingraffea, Anthony R.

    2014-01-01

    The pyroclastic aggregate concrete of Trajan’s Markets (110 CE), now Museo Fori Imperiali in Rome, has absorbed energy from seismic ground shaking and long-term foundation settlement for nearly two millenia while remaining largely intact at the structural scale. The scientific basis of this exceptional service record is explored through computed tomography of fracture surfaces and synchroton X-ray microdiffraction analyses of a reproduction of the standardized hydrated lime–volcanic ash mortar that binds decimeter-sized tuff and brick aggregate in the conglomeratic concrete. The mortar reproduction gains fracture toughness over 180 d through progressive coalescence of calcium–aluminum-silicate–hydrate (C-A-S-H) cementing binder with Ca/(Si+Al) ≈ 0.8–0.9 and crystallization of strätlingite and siliceous hydrogarnet (katoite) at ≥90 d, after pozzolanic consumption of hydrated lime was complete. Platey strätlingite crystals toughen interfacial zones along scoria perimeters and impede macroscale propagation of crack segments. In the 1,900-y-old mortar, C-A-S-H has low Ca/(Si+Al) ≈ 0.45–0.75. Dense clusters of 2- to 30-µm strätlingite plates further reinforce interfacial zones, the weakest link of modern cement-based concrete, and the cementitious matrix. These crystals formed during long-term autogeneous reaction of dissolved calcite from lime and the alkali-rich scoriae groundmass, clay mineral (halloysite), and zeolite (phillipsite and chabazite) surface textures from the Pozzolane Rosse pyroclastic flow, erupted from the nearby Alban Hills volcano. The clast-supported conglomeratic fabric of the concrete presents further resistance to fracture propagation at the structural scale. PMID:25512521

  4. Multiscale Thermohydrologic Model

    SciTech Connect

    T. Buscheck

    2004-10-12

    The purpose of the multiscale thermohydrologic model (MSTHM) is to predict the possible range of thermal-hydrologic conditions, resulting from uncertainty and variability, in the repository emplacement drifts, including the invert, and in the adjoining host rock for the repository at Yucca Mountain. Thus, the goal is to predict the range of possible thermal-hydrologic conditions across the repository; this is quite different from predicting a single expected thermal-hydrologic response. The MSTHM calculates the following thermal-hydrologic parameters: temperature, relative humidity, liquid-phase saturation, evaporation rate, air-mass fraction, gas-phase pressure, capillary pressure, and liquid- and gas-phase fluxes (Table 1-1). These thermal-hydrologic parameters are required to support ''Total System Performance Assessment (TSPA) Model/Analysis for the License Application'' (BSC 2004 [DIRS 168504]). The thermal-hydrologic parameters are determined as a function of position along each of the emplacement drifts and as a function of waste package type. These parameters are determined at various reference locations within the emplacement drifts, including the waste package and drip-shield surfaces and in the invert. The parameters are also determined at various defined locations in the adjoining host rock. The MSTHM uses data obtained from the data tracking numbers (DTNs) listed in Table 4.1-1. The majority of those DTNs were generated from the following analyses and model reports: (1) ''UZ Flow Model and Submodels'' (BSC 2004 [DIRS 169861]); (2) ''Development of Numerical Grids for UZ Flow and Transport Modeling'' (BSC 2004); (3) ''Calibrated Properties Model'' (BSC 2004 [DIRS 169857]); (4) ''Thermal Conductivity of the Potential Repository Horizon'' (BSC 2004 [DIRS 169854]); (5) ''Thermal Conductivity of the Non-Repository Lithostratigraphic Layers'' (BSC 2004 [DIRS 170033]); (6) ''Ventilation Model and Analysis Report'' (BSC 2004 [DIRS 169862]); (7) ''Heat Capacity

  5. Discovering Molecular Targets in Cancer with Multiscale Modeling

    PubMed Central

    Wang, Zhihui; Bordas, Veronika; Deisboeck, Thomas S.

    2011-01-01

    Multiscale modeling is increasingly being recognized as a promising research area in computational cancer systems biology. Here, exemplified by two pioneering studies, we attempt to explain why and how such a multiscale approach paired with an innovative cross-scale analytical technique can be useful in identifying high-value molecular therapeutic targets. This novel, integrated approach has the potential to offer a more effective in silico framework for target discovery and represents an important technical step towards systems medicine. PMID:21572568

  6. Filters for Improvement of Multiscale Data from Atomistic Simulations

    DOE PAGES

    Gardner, David J.; Reynolds, Daniel R.

    2017-01-05

    Multiscale computational models strive to produce accurate and efficient numerical simulations of systems involving interactions across multiple spatial and temporal scales that typically differ by several orders of magnitude. Some such models utilize a hybrid continuum-atomistic approach combining continuum approximations with first-principles-based atomistic models to capture multiscale behavior. By following the heterogeneous multiscale method framework for developing multiscale computational models, unknown continuum scale data can be computed from an atomistic model. Concurrently coupling the two models requires performing numerous atomistic simulations which can dominate the computational cost of the method. Furthermore, when the resulting continuum data is noisy due tomore » sampling error, stochasticity in the model, or randomness in the initial conditions, filtering can result in significant accuracy gains in the computed multiscale data without increasing the size or duration of the atomistic simulations. In this work, we demonstrate the effectiveness of spectral filtering for increasing the accuracy of noisy multiscale data obtained from atomistic simulations. Moreover, we present a robust and automatic method for closely approximating the optimum level of filtering in the case of additive white noise. By improving the accuracy of this filtered simulation data, it leads to a dramatic computational savings by allowing for shorter and smaller atomistic simulations to achieve the same desired multiscale simulation precision.« less

  7. Integrating Multiscale Modeling with Drug Effects for Cancer Treatment.

    PubMed

    Li, Xiangfang L; Oduola, Wasiu O; Qian, Lijun; Dougherty, Edward R

    2015-01-01

    In this paper, we review multiscale modeling for cancer treatment with the incorporation of drug effects from an applied system's pharmacology perspective. Both the classical pharmacology and systems biology are inherently quantitative; however, systems biology focuses more on networks and multi factorial controls over biological processes rather than on drugs and targets in isolation, whereas systems pharmacology has a strong focus on studying drugs with regard to the pharmacokinetic (PK) and pharmacodynamic (PD) relations accompanying drug interactions with multiscale physiology as well as the prediction of dosage-exposure responses and economic potentials of drugs. Thus, it requires multiscale methods to address the need for integrating models from the molecular levels to the cellular, tissue, and organism levels. It is a common belief that tumorigenesis and tumor growth can be best understood and tackled by employing and integrating a multifaceted approach that includes in vivo and in vitro experiments, in silico models, multiscale tumor modeling, continuous/discrete modeling, agent-based modeling, and multiscale modeling with PK/PD drug effect inputs. We provide an example application of multiscale modeling employing stochastic hybrid system for a colon cancer cell line HCT-116 with the application of Lapatinib drug. It is observed that the simulation results are similar to those observed from the setup of the wet-lab experiments at the Translational Genomics Research Institute.

  8. Effect of different dispersants in compressive strength of carbon fiber cementitious composites

    NASA Astrophysics Data System (ADS)

    Lestari, Yulinda; Bahri, Saiful; Sugiarti, Eni; Ramadhan, Gilang; Akbar, Ari Yustisia; Martides, Erie; Khaerudini, Deni S.

    2013-09-01

    Carbon Fiber Cementitious Composites (CFCC) is one of the most important materials in smart concrete applications. CFCC should be able to have the piezoresistivity properties where its resistivity changes when there is applied a stress/strain. It must also have the compressive strength qualification. One of the important additives in carbon fiber cementitious composites is dispersant. Dispersion of carbon fiber is one of the key problems in fabricating piezoresistive carbon fiber cementitious composites. In this research, the uses of dispersants are methylcellulose, mixture of defoamer and methylcellulose and superplasticizer based polycarboxylate. The preparation of composite samples is similar as in the mortar technique according to the ASTM C 109/109M standard. The additives material are PAN type carbon fibers, methylcellulose, defoamer and superplasticizer (as water reducer and dispersant). The experimental testing conducts the compressive strength and resistivity at various curing time, i.e. 3, 7 and 28 days. The results obtained that the highest compressive strength value in is for the mortar using superplasticizer based polycarboxylate dispersant. This also shown that the distribution of carbon fiber with superplasticizer is more effective, since not reacting with the cementitious material which was different from the methylcellulose that creates the cement hydration reaction. The research also found that the CFCC require the proper water cement ratio otherwise the compressive strength becomes lower.

  9. Predicting the Probability of Failure of Cementitious Sewer Pipes Using Stochastic Finite Element Method

    PubMed Central

    Alani, Amir M.; Faramarzi, Asaad

    2015-01-01

    In this paper, a stochastic finite element method (SFEM) is employed to investigate the probability of failure of cementitious buried sewer pipes subjected to combined effect of corrosion and stresses. A non-linear time-dependant model is used to determine the extent of concrete corrosion. Using the SFEM, the effects of different random variables, including loads, pipe material, and corrosion on the remaining safe life of the cementitious sewer pipes are explored. A numerical example is presented to demonstrate the merit of the proposed SFEM in evaluating the effects of the contributing parameters upon the probability of failure of cementitious sewer pipes. The developed SFEM offers many advantages over traditional probabilistic techniques since it does not use any empirical equations in order to determine failure of pipes. The results of the SFEM can help the concerning industry (e.g., water companies) to better plan their resources by providing accurate prediction for the remaining safe life of cementitious sewer pipes. PMID:26068092

  10. Solidification/stabilization of chromite ore processing residue using alkali-activated composite cementitious materials.

    PubMed

    Huang, Xiao; Zhuang, RanLiang; Muhammad, Faheem; Yu, Lin; Shiau, YanChyuan; Li, Dongwei

    2017-02-01

    Chromite Ore Processing Residue (COPR) produced in chromium salt production process causes a great health and environmental risk with Cr(VI) leaching. The solidification/stabilization (S/S) of COPR using alkali-activated blast furnace slag (BFS) and fly ash (FA) based cementitious material was investigated in this study. The optimum percentage of BFS and FA for preparing the alkali-activated BFS-FA binder had been studied. COPR was used to replace the amount of BFS-FA or ordinary Portland cement (OPC) for the preparation of the cementitious materials, respectively. The immobilization effect of the alkali-activated BFS-FA binder on COPR was much better than that of OPC based cementitious material. The potential for reusing the final treatment product as a readily available construction material was evaluated. X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and scanning electron microscope with energy dispersive spectrometer (SEM-EDS) analysis indicated that COPR had been effectively immobilized. The solidification mechanism is the combined effect of reduction, ion exchange, precipitation, adsorption and physical fixation in the alkali-activated composite cementitious material. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Cementitious Composites Engineered with Embedded Carbon Nanotube Thin Films for Enhanced Sensing Performance

    NASA Astrophysics Data System (ADS)

    Loh, Kenneth J.; Gonzalez, Jesus

    2015-07-01

    Cementitious composites such as concrete pavements are susceptible to different damage modes, which are primarily caused by repeated loading and long-term deterioration. There is even greater concern that damage could worsen and occur more frequently with the use of heavier vehicles or new aircraft carrying greater payloads. Thus, the objective of this research is to engineer cementitious composites with capabilities of self-sensing or detecting damage. The approach was to enhance the damage sensitivity of cementitious composites by incorporating multi-walled carbon nanotubes (MWNT) as part of the mix design and during casting. However, as opposed to directly dispersing MWNTs in the cement matrix, which is the current state-of-art, MWNT-based thin films were airbrushed and coated onto sand particles. The film-coated sand was then used as part of the mix design for casting mortar specimens. Mortar specimens were subjected to compressive cyclic loading tests while their electrical properties were recorded simultaneously. The results showed that the electrical properties of these cementitious composites designed with film-coated sand exhibited extremely high strain sensitivities. The electrical response was also stable and consistent between specimens.

  12. Concurrent Multiscale Modeling of Embedded Nanomechanics

    SciTech Connect

    Rudd, R E

    2001-04-13

    We discuss concurrent multiscale simulations of dynamic and temperature-dependent processes found in nanomechanical systems coupled to larger scale surroundings. We focus on the behavior of sub-micron Micro-Electro-Mechanical Systems (MEMS), especially micro-resonators. The coupling of length scales methodology we have developed for MEMS employs an atomistic description of small but key regions of the system, consisting of millions of atoms, coupled concurrently to a finite element model of the periphery. The result is a model that accurately describes the behavior of the mechanical components of MEMS down to the atomic scale. This paper reviews some of the general issues involved in concurrent multiscale simulation, extends the methodology to metallic systems and describes how it has been used to identify atomistic effects in sub-micron resonators.

  13. Development and characterization of acoustically efficient cementitious materials

    NASA Astrophysics Data System (ADS)

    Neithalath, Narayanan

    Tire-pavement interaction noise is one of the significant environmental issues in highly populated urban areas situated near busy highways. The understanding that methodologies to reduce the sound at the source itself is necessary, has led to the development of porous paving materials. This thesis outlines the systematic research effort conducted in order to develop and characterize two different types of sound absorbing cementitious materials---Enhanced Porosity Concrete (EPC), that incorporates porosity in the non-aggregate component of the mixture, and Cellulose-Cement Composites, where cellulose fibers are used as porous inclusions. The basic tenet of this research is that carefully introduced porosity of about 15%--25% in the material structure of concrete will allow sound waves to pass through and dissipate its energy. The physical, mechanical, and acoustic properties of EPC mixtures are discussed in detail. Methods are developed to determine the porosity of EPC. The total pore volume, pore size, and pore connectivity are the significant features that influence the behavior of EPC. Using a shape-specific model, and incorporating the principle of acoustic wave propagation through semi-open cells, the acoustic absorption in EPC has been modeled. The pore structure and performance of EPC is characterized using Electrical Impedance Spectroscopy. Using a multi-phase conducting model, a pore connectivity factor has been developed, that correlates well with the acoustic absorption coefficient. A falling head permeameter has been designed to ascertain the water permeability of EPC mixtures. A hydraulic connectivity factor is proposed, which could be used to classify EPC mixtures based on their permeability. Electrical conductivity is shown to be a single measurable parameter that defines the performance of EPC. Preliminary studies conducted on the freezing and thawing response of EPC are also reported. From several porous, compliant materials, morphologically altered

  14. Multiscale simulation of molecular processes in cellular environments.

    PubMed

    Chiricotto, Mara; Sterpone, Fabio; Derreumaux, Philippe; Melchionna, Simone

    2016-11-13

    We describe the recent advances in studying biological systems via multiscale simulations. Our scheme is based on a coarse-grained representation of the macromolecules and a mesoscopic description of the solvent. The dual technique handles particles, the aqueous solvent and their mutual exchange of forces resulting in a stable and accurate methodology allowing biosystems of unprecedented size to be simulated.This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.

  15. Multiscale simulation of molecular processes in cellular environments

    NASA Astrophysics Data System (ADS)

    Chiricotto, Mara; Sterpone, Fabio; Derreumaux, Philippe; Melchionna, Simone

    2016-11-01

    We describe the recent advances in studying biological systems via multiscale simulations. Our scheme is based on a coarse-grained representation of the macromolecules and a mesoscopic description of the solvent. The dual technique handles particles, the aqueous solvent and their mutual exchange of forces resulting in a stable and accurate methodology allowing biosystems of unprecedented size to be simulated. This article is part of the themed issue 'Multiscale modelling at the physics-chemistry-biology interface'.

  16. On the Application of Inertial Microfluidics for the Size-Based Separation of Polydisperse Cementitious Particulates

    NASA Astrophysics Data System (ADS)

    Kumar, Aditya; Lewis, Peter; Balonis, Magdalena; Di Carlo, Dino; Sant, Gaurav

    2015-06-01

    The early-age performance of concrete is determined by the properties of the cementitious binder and the evolution of its chemical reactions. The chemical reactivity, and to some extent, the composition of cementitious particles can depend on particle size. Therefore, it is valuable to physically separate cementing minerals into well-defined size classes so that the influences of both particle size and composition on reaction progress can be studied without the confounding effects of a broad particle size distribution. However, conventional particle separation methods (e.g., density fractionation, wet sieving, field-flow extraction, ultrasonification-sedimentation) are time-consuming and cumbersome and result in poor particle yields and size-selectivity, thus, making them unsuitable for processing larger volumes of cementitious powders (on the order of grams). This study applies a novel inertial microfluidics (IMF) based procedure to separate cementitious powders on the basis of their size. Special attention is paid to optimizing operating variables to ensure that particles in a fluid streamline achieve unique equilibrium positions within the device. From such positions, particles can be retrieved as per their size using symmetrical outlet configurations with tuned fluidic resistances. The approach is critically assessed in terms of: (1) its ability to separate cementitious powders into narrow size bins, and therefore its feasibility as a fractionation procedure, and (2) quantitatively relating the operating parameters to the particle yield and size selectivity. The study establishes metrics for assessing the ability of IMF methods to classify minerals and other polydisperse particles on the basis of their size.

  17. Multi-scale Analysis of Ionospheric Wave Activity as Observed by the Very Large Array VHF System

    NASA Astrophysics Data System (ADS)

    Helmboldt, J.; Intema, H.

    2011-12-01

    We present the results of a multi-scale analysis of ionospheric TEC fluctuations using a nearly six hour observation of the bright radio source Virgo A with the Very Large Array (VLA) at 74 MHz. Our analysis combines data sensitive to fine-scale structure (~1 km and ~0.001 TECU in amplitude) along the line of sight to Virgo A as well as larger structures (up to hundreds of km) observed using several (~30) moderately bright sources in the field of view. The observations span a time period from midnight to dawn local time during 1 March 2001. MSTIDs are visible intermittently throughout the night, most prominently near dawn. These appear to be mostly directed westward or southwestward with some atypical MSTID-like waves directed toward the north or northwest. Many smaller-scale (between 10 and 50 km) waves are present beginning around 01:30 and are directed toward either the southeast or southwest/west. These are reminiscent of QP-echoes observed with other experiments. The southeastward-directed waves dominate during the beginning of this time period when larger (>50 km) waves are seen moving toward the northwest. As the southwestward/westward-directed QP-echo-like waves begin to dominate around 03:00, the larger waves transition to being predominantly directed toward the west or southwest. The coincidence of these two phenomena may suggest the presence of the direction-dependent E-F coupling instability if the smaller-scale waves are generated within sporadic-E layers. In addition to MSTID- and QP-echo-like waves, we also find evidence of wave-like disturbances as small as ~2 km, most frequently between 02:00 and 04:00. While their sizes and the "Y" pattern of the VLA make their directions difficult to determine, these waves are seen most strongly along antennas in the northern arm of the VLA, suggesting they were roughly traveling in the north-south direction.

  18. MMS (Magnetospheric Multiscale) Arrival

    NASA Image and Video Library

    2014-11-12

    Operations are underway to remove two of the the Magnetospheric Multiscale spacecraft from their protective shipping container in the airlock of Building 2 at the Astrotech payload processing facility in Titusville, Florida, near Kennedy Space Center. The Magnetospheric Multiscale mission, or MMS, is a Solar Terrestrial Probes mission comprising four identically instrumented spacecraft that will use Earth’s magnetosphere as a laboratory to study the microphysics of three fundamental plasma processes: magnetic reconnection, energetic particle acceleration and turbulence. These two spacecraft comprise the mission's upper stack. The two MMS spacecraft comprising the lower stack arrived at Astrotech on Oct. 29. Launch aboard a United Launch Alliance Atlas V rocket from Space Launch Complex 41 on Cape Canaveral Air Force Station is targeted for March 12, 2015.

  19. MMS (Magnetospheric Multiscale) Arrival

    NASA Image and Video Library

    2014-11-12

    Two Magnetospheric Multiscale spacecraft, enclosed in a protective shipping container, are positioned into the airlock of Building 2 of the Astrotech payload processing facility in Titusville, Florida, near Kennedy Space Center. The Magnetospheric Multiscale mission, or MMS, is a Solar Terrestrial Probes mission comprising four identically instrumented spacecraft that will use Earth’s magnetosphere as a laboratory to study the microphysics of three fundamental plasma processes: magnetic reconnection, energetic particle acceleration and turbulence. These two spacecraft comprise the mission's upper stack. The two MMS spacecraft comprising the lower stack arrived at Astrotech on Oct. 29. Launch aboard a United Launch Alliance Atlas V rocket from Space Launch Complex 41 on Cape Canaveral Air Force Station is targeted for March 12, 2015.

  20. MMS (Magnetospheric Multiscale) Arrival

    NASA Image and Video Library

    2014-11-12

    The airlock door opens at Building 2 of the Astrotech payload processing facility in Titusville, Florida, near Kennedy Space Center, for ingress of the protective shipping container enclosing the Magnetospheric Multiscale spacecraft. The Magnetospheric Multiscale mission, or MMS, is a Solar Terrestrial Probes mission comprising four identically instrumented spacecraft that will use Earth’s magnetosphere as a laboratory to study the microphysics of three fundamental plasma processes: magnetic reconnection, energetic particle acceleration and turbulence. These two spacecraft comprise the mission's upper stack. The two MMS spacecraft comprising the lower stack arrived at Astrotech on Oct. 29. Launch aboard a United Launch Alliance Atlas V rocket from Space Launch Complex 41 on Cape Canaveral Air Force Station is targeted for March 12, 2015.

  1. Spatial patterns and eco-epidemiological systems--part I: multi-scale spatial modelling of the occurrence of Chagas disease insect vectors.

    PubMed

    Roux, Emmanuel; de Fátima Venâncio, Annamaria; Girres, Jean-François; Romaña, Christine A

    2011-11-01

    Studies that explicitly and specifically take into account the spatial dimension within the study of eco-epidemiological systems remain rare. Our approach of modelling the spatial and/or temporal properties of the entomological and/or epidemiological data before their mapping with possible explanatory variables, objectively underline the significant patterns at different scales. The domiciliary and peri-domiciliary presence and abundance of juvenile and adult vectors of the Chagas disease (Triatoma sordida and Panstrongylus geniculatus) in Bahia state in northeast Brazil, has been modelled by automatically identifying significant multi-scale spatial patterns of the entomological data by the application and adoption of the spatial modelling methodology proposed by Dray et al. (2006) and based on principal coordinate analysis of neighbour matrices. We found that entomological data can be modelled by a set of eigenvectors that present a significant Moran's I index of spatial autocorrelation. The models for juvenile and adult vectors are defined by 28 and 32 eigenvectors that explain 82.3% and 79.9%, respectively, of the total data variances. The results support insect presence as the outcome both of a local scale "near-to-near" dispersal and an infestation from the wild, surrounding environment that produces a higher insect density at the village periphery.

  2. Multi-Scale In Vivo Systems Analysis Reveals the Influence of Immune Cells on TNF-α-Induced Apoptosis in the Intestinal Epithelium

    PubMed Central

    Lau, Ken S.; Cortez-Retamozo, Virna; Philips, Sarah R.; Pittet, Mikael J.; Lauffenburger, Douglas A.; Haigis, Kevin M.

    2012-01-01

    Intestinal epithelial cells exist within a complex environment that affects how they interpret and respond to stimuli. We have applied a multi-scale in vivo systems approach to understand how intestinal immune cells communicate with epithelial cells to regulate responses to inflammatory signals. Multivariate modeling analysis of a large dataset composed of phospho-signals, cytokines, and immune cell populations within the intestine revealed an intimate relationship between immune cells and the epithelial response to TNF-α. Ablation of lymphocytes in the intestine prompted a decrease in the expression of MCP-1, which in turn increased the steady state number of intestinal plasmacytoid dendritic cells (pDCs). This change in the immune compartment affected the intestinal cytokine milieu and subsequent epithelial cell signaling network, with cells becoming hypersensitive to TNF-α-induced apoptosis in a way that could be predicted by mathematical modeling. In summary, we have uncovered a novel cellular network that regulates the response of intestinal epithelial cells to inflammatory stimuli in an in vivo setting. PMID:23055830

  3. Assimilation of high-resolution sea surface temperature data into an operational nowcast/forecast system around Japan using a multi-scale three-dimensional variational scheme

    NASA Astrophysics Data System (ADS)

    Miyazawa, Yasumasa; Varlamov, Sergey M.; Miyama, Toru; Guo, Xinyu; Hihara, Tsutomu; Kiyomatsu, Keiji; Kachi, Misako; Kurihara, Yukio; Murakami, Hiroshi

    2017-06-01

    A multi-scale three-dimensional variational (MS-3DVAR) scheme is developed to assimilate high-resolution Himawari-8 sea surface temperature (SST) data for the first time into an operational ocean nowcast/forecast system targeting the North Western Pacific, JCOPE2. MS-3DVAR improves representation of the Kuroshio path south of Japan, its associated sea level variations, and temperature/salinity profiles south of Japan, the Kuroshio/Oyashio mixed water region, and the Japan Sea as compared to those of the products by the traditional single-scale 3DVAR. Validation results demonstrate that MS-3DVAR well assimilates the sparsely distributed in situ temperature and salinity profiles data by spreading the information over the large scale and by representing the detailed information near the measurement points. MS-3DVAR succeeds to assimilate the Himawari-8 SST product without noisy features caused by the cloud effects. We also find that MS-3DVAR is more effective for estimating oceanic conditions in regions with smaller mesoscale variability including the mixed water region and Japan Sea than in south of Japan.

  4. Multiscale Data Assimilation

    DTIC Science & Technology

    2014-09-30

    were developed. Two of them include non-hydrostatic flows behind a seamount (Fig. 1) and non-hydrostatic bottom gravity currents (Fig. 2). In the... seamount test case, flows with varying Reynolds number were studied. The resulting different parameter regimes highlight different multiscale physics at...the seamount including vortex generation, lee waves and unstable flows (to name a few). These different flow regimes are currently being used to

  5. Multiscale dynamics in relaxor ferroelectrics

    SciTech Connect

    Toulouse, J.; Cai, L; Pattnaik, R. K.; Boatner, Lynn A

    2014-01-01

    The multiscale dynamics of complex oxides is illustrated by pairs of mechanical resonances that are excited in the relaxor ferroelectric K1 xLixTaO3 (KLT). These macroscopic resonances are shown to originate in the collective dynamics of piezoelectric polar nanodomains (PND) interacting with the surrounding lattice. Their characteristic Fano lineshapes and rapid evolution with temperature reveal the coherent interplay between the piezoelectric oscillations and orientational relaxations of the PNDs at higher temperature and the contribution of heterophase oscillations near the phase transition. A theoretical model is presented, that describes the evolution of the resonances over the entire temperature range. Similar resonances are observed in other relaxors and must therefore be a common characteristics of these systems.

  6. Multi-scale modeling in cell biology

    PubMed Central

    Meier-Schellersheim, Martin; Fraser, Iain D. C.; Klauschen, Frederick

    2009-01-01

    Biomedical research frequently involves performing experiments and developing hypotheses that link different scales of biological systems such as, for instance, the scales of intracellular molecular interactions to the scale of cellular behavior and beyond to the behavior of cell populations. Computational modeling efforts that aim at exploring such multi-scale systems quantitatively with the help of simulations have to incorporate several different simulation techniques due to the different time and space scales involved. Here, we provide a non-technical overview of how different scales of experimental research can be combined with the appropriate computational modeling techniques. We also show that current modeling software permits building and simulating multi-scale models without having to become involved with the underlying technical details of computational modeling. PMID:20448808

  7. Development and Demonstration of Material Properties Database and Software for the Simulation of Flow Properties in Cementitious Materials

    SciTech Connect

    Smith, F.; Flach, G.

    2015-03-30

    This report describes work performed by the Savannah River National Laboratory (SRNL) in fiscal year 2014 to develop a new Cementitious Barriers Project (CBP) software module designated as FLOExcel. FLOExcel incorporates a uniform database to capture material characterization data and a GoldSim model to define flow properties for both intact and fractured cementitious materials and estimate Darcy velocity based on specified hydraulic head gradient and matric tension. The software module includes hydraulic parameters for intact cementitious and granular materials in the database and a standalone GoldSim framework to manipulate the data. The database will be updated with new data as it comes available. The software module will later be integrated into the next release of the CBP Toolbox, Version 3.0. This report documents the development efforts for this software module. The FY14 activities described in this report focused on the following two items that form the FLOExcel package; 1) Development of a uniform database to capture CBP data for cementitious materials. In particular, the inclusion and use of hydraulic properties of the materials are emphasized; and 2) Development of algorithms and a GoldSim User Interface to calculate hydraulic flow properties of degraded and fractured cementitious materials. Hydraulic properties are required in a simulation of flow through cementitious materials such as Saltstone, waste tank fill grout, and concrete barriers. At SRNL these simulations have been performed using the PORFLOW code as part of Performance Assessments for salt waste disposal and waste tank closure.

  8. Multi-Scale Ionospheric Responses to the St. Patrick's Day Storm (2015) Studied Using a Multimodel Ensemble Prediction System and GPS Data

    NASA Astrophysics Data System (ADS)

    Pi, X.; Butala, M.; Vergados, P.; Mannucci, A. J.; Komjathy, A.; Wang, C.; Rosen, G.; Schunk, R. W.; Scherliess, L.; Eccles, V.; Gardner, L. C.; Sojka, J. J.; Zhu, L.

    2015-12-01

    Under the U.S. NASA and NSF collaborative space weather modeling initiative, a Multimodel Ensemble Prediction System (MEPS) for ionosphere-thermosphere-electrodynamics is being developed. The system includes several Global Assimilative Ionospheric Models (GAIMs) developed by the investigators from Utah State University, Jet Propulsion Laboratory, and University of Southern California. In this study, four GAIMs are applied to a study of ionospheric response to the 17 March 2015 St. Patrick's Day storm. It is the most severe geomagnetic storm in the current solar cycle so far. The daily planetary magnetic Ap index and magnetic Kp, Dst, as well as AE indices reached their very high values, i.e., 108, 8, -202 nT, and 2269 nT, respectively. In the assimilative modeling, GPS data from hundreds of globally-distributed ground stations and a number of COSMIC satellites are assimilated into GAIMs to reproduce ionospheric 3-D volume densities and 2-D total electron content (TEC) during the severe storm. Evolution of strong, latitudinally-dependent, and hemispherically asymmetric ionospheric disturbances is revealed through the assimilative modeling. Using the same GPS data, Global Maps of Ionospheric Irregularities and Scintillation (GMIIS) have also been produced. Comparisons of the modeled large-scale ionospheric disturbances and measured small-scale ionospheric irregularities offer additional insight into the M-I-T coupling processes in different regions during varying storm phases. This presentation will provide a picture of distinguished multi-scale ionospheric response to the coronal mass ejection (CME) event during the major geomagnetic storm.

  9. Nonlinear dynamical systems effects of homeopathic remedies on multiscale entropy and correlation dimension of slow wave sleep EEG in young adults with histories of coffee-induced insomnia.

    PubMed

    Bell, Iris R; Howerter, Amy; Jackson, Nicholas; Aickin, Mikel; Bootzin, Richard R; Brooks, Audrey J

    2012-07-01

    Investigators of homeopathy have proposed that nonlinear dynamical systems (NDS) and complex systems science offer conceptual and analytic tools for evaluating homeopathic remedy effects. Previous animal studies demonstrate that homeopathic medicines alter delta electroencephalographic (EEG) slow wave sleep. The present study extended findings of remedy-related sleep stage alterations in human subjects by testing the feasibility of using two different NDS analytic approaches to assess remedy effects on human slow wave sleep EEG. Subjects (N=54) were young adult male and female college students with a history of coffee-related insomnia who participated in a larger 4-week study of the polysomnographic effects of homeopathic medicines on home-based all-night sleep recordings. Subjects took one bedtime dose of a homeopathic remedy (Coffea cruda or Nux vomica 30c). We computed multiscale entropy (MSE) and the correlation dimension (Mekler-D2) for stages 3 and 4 slow wave sleep EEG sampled in artifact-free 2-min segments during the first two rapid-eye-movement (REM) cycles for remedy and post-remedy nights, controlling for placebo and post-placebo night effects. MSE results indicate significant, remedy-specific directional effects, especially later in the night (REM cycle 2) (CC: remedy night increases and post-remedy night decreases in MSE at multiple sites for both stages 3 and 4 in both REM cycles; NV: remedy night decreases and post-remedy night increases, mainly in stage 3 REM cycle 2 MSE). D2 analyses yielded more sporadic and inconsistent findings. Homeopathic medicines Coffea cruda and Nux vomica in 30c potencies alter short-term nonlinear dynamic parameters of slow wave sleep EEG in healthy young adults. MSE may provide a more sensitive NDS analytic method than D2 for evaluating homeopathic remedy effects on human sleep EEG patterns. Copyright © 2012 The Faculty of Homeopathy. Published by Elsevier Ltd. All rights reserved.

  10. Nonlinear Dynamical Systems Effects of Homeopathic Remedies on Multiscale Entropy and Correlation Dimension of Slow Wave Sleep EEG in Young Adults with Histories of Coffee-Induced Insomnia

    PubMed Central

    Bell, Iris R.; Howerter, Amy; Jackson, Nicholas; Aickin, Mikel; Bootzin, Richard R.; Brooks, Audrey J.

    2012-01-01

    Background Investigators of homeopathy have proposed that nonlinear dynamical systems (NDS) and complex systems science offer conceptual and analytic tools for evaluating homeopathic remedy effects. Previous animal studies demonstrate that homeopathic medicines alter delta electroencephalographic (EEG) slow wave sleep. The present study extended findings of remedy-related sleep stage alterations in human subjects by testing the feasibility of using two different NDS analytic approaches to assess remedy effects on human slow wave sleep EEG. Methods Subjects (N=54) were young adult male and female college students with a history of coffee-related insomnia who participated in a larger 4-week study of the polysomnographic effects of homeopathic medicines on home-based all-night sleep recordings. Subjects took one bedtime dose of a homeopathic remedy (Coffea cruda or Nux vomica 30c). We computed multiscale entropy (MSE) and the correlation dimension (Mekler-D2) for stage 3 and 4 slow wave sleep EEG sampled in artifact-free 2-minute segments during the first two rapid-eye-movement (REM) cycles for remedy and post-remedy nights, controlling for placebo and post-placebo night effects. Results MSE results indicate significant, remedy-specific directional effects, especially later in the night (REM cycle 2) (CC: remedy night increases and post-remedy night decreases in MSE at multiple sites for both stages 3 and 4 in both REM cycles; NV: remedy night decreases and post-remedy night increases, mainly in stage 3 REM cycle 2 MSE). D2 analyses yielded more sporadic and inconsistent findings. Conclusions Homeopathic medicines Coffea cruda and Nux vomica in 30c potencies alter short-term nonlinear dynamic parameters of slow wave sleep EEG in healthy young adults. MSE may provide a more sensitive NDS analytic method than D2 for evaluating homeopathic remedy effects on human sleep EEG patterns. PMID:22818237

  11. New Method for Accurate Calibration of Micro-Channel Plate based Detection Systems and its use in the Fast Plasma Investigation of NASA's Magnetospheric MultiScale Mission

    NASA Astrophysics Data System (ADS)

    Gliese, U.; Avanov, L. A.; Barrie, A.; Kujawski, J. T.; Mariano, A. J.; Tucker, C. J.; Chornay, D. J.; Cao, N. T.; Zeuch, M.; Pollock, C. J.; Jacques, A. D.

    2013-12-01

    The Fast Plasma Investigation (FPI) of the NASA Magnetospheric MultiScale (MMS) mission employs 16 Dual Electron Spectrometers (DESs) and 16 Dual Ion Spectrometers (DISs) with 4 of each type on each of 4 spacecraft to enable fast (30ms for electrons; 150ms for ions) and spatially differentiated measurements of full the 3D particle velocity distributions. This approach presents a new and challenging aspect to the calibration and operation of these instruments on ground and in flight. The response uniformity and reliability of their calibration and the approach to handling any temporal evolution of these calibrated characteristics all assume enhanced importance in this application, where we attempt to understand the meaning of particle distributions within the ion and electron diffusion regions. Traditionally, the micro-channel plate (MCP) based detection systems for electrostatic particle spectrometers have been calibrated by setting a fixed detection threshold and, subsequently, measuring a detection system count rate plateau curve to determine the MCP voltage that ensures the count rate has reached a constant value independent of further variation in the MCP voltage. This is achieved when most of the MCP pulse height distribution (PHD) is located at higher values (larger pulses) than the detection amplifier threshold. This method is adequate in single-channel detection systems and in multi-channel detection systems with very low crosstalk between channels. However, in dense multi-channel systems, it can be inadequate. Furthermore, it fails to fully and individually characterize each of the fundamental parameters of the detection system. We present a new detection system calibration method that enables accurate and repeatable measurement and calibration of MCP gain, MCP efficiency, signal loss due to variation in gain and efficiency, crosstalk from effects both above and below the MCP, noise margin, and stability margin in one single measurement. The fundamental

  12. Multiscale modeling of mucosal immune responses

    PubMed Central

    2015-01-01

    Computational modeling techniques are playing increasingly important roles in advancing a systems-level mechanistic understanding of biological processes. Computer simulations guide and underpin experimental and clinical efforts. This study presents ENteric Immune Simulator (ENISI), a multiscale modeling tool for modeling the mucosal immune responses. ENISI's modeling environment can simulate in silico experiments from molecular signaling pathways to tissue level events such as tissue lesion formation. ENISI's architecture integrates multiple modeling technologies including ABM (agent-based modeling), ODE (ordinary differential equations), SDE (stochastic modeling equations), and PDE (partial differential equations). This paper focuses on the implementation and developmental challenges of ENISI. A multiscale model of mucosal immune responses during colonic inflammation, including CD4+ T cell differentiation and tissue level cell-cell interactions was developed to illustrate the capabilities, power and scope of ENISI MSM. Background Computational techniques are becoming increasingly powerful and modeling tools for biological systems are of greater needs. Biological systems are inherently multiscale, from molecules to tissues and from nano-seconds to a lifespan of several years or decades. ENISI MSM integrates multiple modeling technologies to understand immunological processes from signaling pathways within cells to lesion formation at the tissue level. This paper examines and summarizes the technical details of ENISI, from its initial version to its latest cutting-edge implementation. Implementation Object-oriented programming approach is adopted to develop a suite of tools based on ENISI. Multiple modeling technologies are integrated to visualize tissues, cells as well as proteins; furthermore, performance matching between the scales is addressed. Conclusion We used ENISI MSM for developing predictive multiscale models of the mucosal immune system during gut

  13. Multiscale modeling of mucosal immune responses.

    PubMed

    Mei, Yongguo; Abedi, Vida; Carbo, Adria; Zhang, Xiaoying; Lu, Pinyi; Philipson, Casandra; Hontecillas, Raquel; Hoops, Stefan; Liles, Nathan; Bassaganya-Riera, Josep

    2015-01-01

    Computational techniques are becoming increasingly powerful and modeling tools for biological systems are of greater needs. Biological systems are inherently multiscale, from molecules to tissues and from nano-seconds to a lifespan of several years or decades. ENISI MSM integrates multiple modeling technologies to understand immunological processes from signaling pathways within cells to lesion formation at the tissue level. This paper examines and summarizes the technical details of ENISI, from its initial version to its latest cutting-edge implementation. Object-oriented programming approach is adopted to develop a suite of tools based on ENISI. Multiple modeling technologies are integrated to visualize tissues, cells as well as proteins; furthermore, performance matching between the scales is addressed. We used ENISI MSM for developing predictive multiscale models of the mucosal immune system during gut inflammation. Our modeling predictions dissect the mechanisms by which effector CD4+ T cell responses contribute to tissue damage in the gut mucosa following immune dysregulation.Computational modeling techniques are playing increasingly important roles in advancing a systems-level mechanistic understanding of biological processes. Computer simulations guide and underpin experimental and clinical efforts. This study presents ENteric Immune Simulator (ENISI), a multiscale modeling tool for modeling the mucosal immune responses. ENISI's modeling environment can simulate in silico experiments from molecular signaling pathways to tissue level events such as tissue lesion formation. ENISI's architecture integrates multiple modeling technologies including ABM (agent-based modeling), ODE (ordinary differential equations), SDE (stochastic modeling equations), and PDE (partial differential equations). This paper focuses on the implementation and developmental challenges of ENISI. A multiscale model of mucosal immune responses during colonic inflammation, including CD4+ T

  14. The Magnetospheric Multiscale Mission

    NASA Astrophysics Data System (ADS)

    Burch, James

    Magnetospheric Multiscale (MMS), a NASA four-spacecraft mission scheduled for launch in November 2014, will investigate magnetic reconnection in the boundary regions of the Earth’s magnetosphere, particularly along its dayside boundary with the solar wind and the neutral sheet in the magnetic tail. Among the important questions about reconnection that will be addressed are the following: Under what conditions can magnetic-field energy be converted to plasma energy by the annihilation of magnetic field through reconnection? How does reconnection vary with time, and what factors influence its temporal behavior? What microscale processes are responsible for reconnection? What determines the rate of reconnection?
In order to accomplish its goals the MMS spacecraft must probe both those regions in which the magnetic fields are very nearly antiparallel and regions where a significant guide field exists. From previous missions we know the approximate speeds with which reconnection layers move through space to be from tens to hundreds of km/s. For electron skin depths of 5 to 10 km, the full 3D electron population (10 eV to above 20 keV) has to be sampled at rates greater than 10/s. The MMS Fast-Plasma Instrument (FPI) will sample electrons at greater than 30/s. Because the ion skin depth is larger, FPI will make full ion measurements at rates of greater than 6/s. 3D E-field measurements will be made by MMS once every ms. MMS will use an Active Spacecraft Potential Control device (ASPOC), which emits indium ions to neutralize the photoelectron current and keep the spacecraft from charging to more than +4 V. Because ion dynamics in Hall reconnection depend sensitively on ion mass, MMS includes a new-generation Hot Plasma Composition Analyzer (HPCA) that corrects problems with high proton fluxes that have prevented accurate ion-composition measurements near the dayside magnetospheric boundary. Finally, Energetic Particle Detector (EPD) measurements of electrons and

  15. Evaluation of the Community Multiscale Air Quality (CMAQ) modeling system against size-resolved measurements of inorganic particle composition across sites in North America

    EPA Science Inventory

    This work evaluates particle size-composition distributions simulated by the Community Multiscale Air Quality (CMAQ) model using Micro-Orifice Uniform Deposit Impactor (MOUDI) measurements at 18 sites across North America. Size-resolved measurements of particulate SO4<...

  16. Evaluation of the Community Multiscale Air Quality (CMAQ) modeling system against size-resolved measurements of inorganic particle composition across sites in North America

    EPA Science Inventory

    This work evaluates particle size-composition distributions simulated by the Community Multiscale Air Quality (CMAQ) model using Micro-Orifice Uniform Deposit Impactor (MOUDI) measurements at 18 sites across North America. Size-resolved measurements of particulate SO4<...

  17. Effect of extraction solutions on carbonation of cementitious materials in aqueous solutions.

    PubMed

    Jo, Hwanju; Jo, Ho Young; Jang, Young-Nam

    2012-06-01

    Carbonation efficiency was evaluated for three cementitious materials having different CaO-bearing minerals (lime, Portland cement and waste concrete) using various extraction reagents (HCl, CH3COOH, NH4Cl and deionized water). The cementitious materials were subjected to Ca extraction and carbonation tests under ambient pressure and temperature conditions. The Ca extraction efficiency generally decreased in the order lime, Portland cement and waste concrete, regardless of the extraction solution. Among the extraction solutions, NH4Cl was the most effective for Ca extraction and carbonation. The results of this study suggest that the types of extraction solution and CaO-bearing mineral of the materials are primary factors affecting carbonation efficiency.

  18. Methyl methacrylate as a healing agent for self-healing cementitious materials

    NASA Astrophysics Data System (ADS)

    Van Tittelboom, K.; Adesanya, K.; Dubruel, P.; Van Puyvelde, P.; De Belie, N.

    2011-12-01

    Different types of healing agents have already been tested on their efficiency for use in self-healing cementitious materials. Generally, commercial healing agents are used while their properties are adjusted for manual crack repair and not for autonomous crack healing. Consequently, the amount of regain in properties due to self-healing of cracks is limited. In this research, a methyl methacrylate (MMA)-based healing agent was developed specifically for use in self-healing cementitious materials. Various parameters were optimized including the viscosity, curing time, strength, etc. After the desired properties were obtained, the healing agent was encapsulated and screened for its self-healing efficiency. The decrease in water permeability due to autonomous crack healing using MMA as a healing agent was similar to the results obtained for manually healed cracks. First results seem promising: however, further research needs to be undertaken in order to obtain an optimal healing agent ready for use in practice.

  19. Lead waste glasses management: Chemical pretreatment for use in cementitious composites.

    PubMed

    Bursi, Elena; Barbieri, Luisa; Lancellotti, Isabella; Saccani, Andrea; Bignozzi, Maria

    2017-09-01

    This article investigates the effect of a low-impact chemical treatment based on a nitrilotriacetic acid chelating agent on the reactivity of funnel glass derived from discarded cathode ray tubes. Treated and untreated glass has been recycled either as a supplementary cementing material or as a fine aggregate in cementitious mortars. The effect of the treatment on the chemical and morphological properties of cullets, as well as on the solubility in an alkaline environment has been evaluated. Data so far collected underline a change in glass cullets characteristics that consequently affects their behaviour in cementitious mortars, reducing the pozzolanic activity as supplementary cementing material, but strongly decreasing the tendency towards alkali silica reactions when added as a fine aggregate. The leaching behaviour of lead on treated and untreated glass and on derived composites has been determined to verify the sustainability of the prepared materials.

  20. Effect of Undensified Silica Fume on the Dispersion of Carbon Nanotubes within a Cementitious Composite

    NASA Astrophysics Data System (ADS)

    Alrekabi, S.; Cundy, A.; Whitby, Raymond L. D.; Lampropoulos, A.; Savina, I.

    2017-04-01

    The synergistic effect of multi-walled carbon nanotubes (MWCNTs) and Undensified Silica Fume (USF) on the microstructure of cementitious composites has been studied. In the current work, USF was used to enhance the dispersion of nanotubes throughout the composite and prevent the re-agglomeration of nanotubes by providing a physical barrier of particles of small size. Ultrasonication was employed to disperse MWCNTs in water in the presence of polycarboxylate-based superplasticizer (PCE) as a dispersion agent. The results indicate that incorporation of USF considerably improves the dispersion of nanotubes in the composites, with subsequent enhancement of composite packing density. This enhancement can be attributed to the synergistic effect of MWCNTs and USF in reducing the volume of pores through the cementitious composites.

  1. Secondary Waste Cementitious Waste Form Data Package for the Integrated Disposal Facility Performance Assessment

    SciTech Connect

    Cantrell, Kirk J.; Westsik, Joseph H.; Serne, R Jeffrey; Um, Wooyong; Cozzi, Alex D.

    2016-05-16

    A review of the most up-to-date and relevant data currently available was conducted to develop a set of recommended values for use in the Integrated Disposal Facility (IDF) performance assessment (PA) to model contaminant release from a cementitious waste form for aqueous wastes treated at the Hanford Effluent Treatment Facility (ETF). This data package relies primarily upon recent data collected on Cast Stone formulations fabricated with simulants of low-activity waste (LAW) and liquid secondary wastes expected to be produced at Hanford. These data were supplemented, when necessary, with data developed for saltstone (a similar grout waste form used at the Savannah River Site). Work is currently underway to collect data on cementitious waste forms that are similar to Cast Stone and saltstone but are tailored to the characteristics of ETF-treated liquid secondary wastes. Recommended values for key parameters to conduct PA modeling of contaminant release from ETF-treated liquid waste are provided.

  2. Hydration kinetics of cementitious materials composed of red mud and coal gangue

    NASA Astrophysics Data System (ADS)

    Zhang, Na; Li, Hong-xu; Liu, Xiao-ming

    2016-10-01

    To elucidate the intrinsic reaction mechanism of cementitious materials composed of red mud and coal gangue (RGC), the hydration kinetics of these cementitious materials at 20°C was investigated on the basis of the Krstulović-Dabić model. An isothermal calorimeter was used to characterize the hydration heat evolution. The results show that the hydration of RGC is controlled by the processes of nucleation and crystal growth (NG), interaction at phase boundaries (I), and diffusion (D) in order, and the pozzolanic reactions of slag and compound-activated red mud-coal gangue are mainly controlled by the I process. Slag accelerates the clinker hydration during NG process, whereas the compound-activated red mud-coal gangue retards the hydration of RGC and the time required for I process increases with increasing dosage of red mud-coal gangue in RGC.

  3. Multiscale perspectives of virus entry via endocytosis.

    PubMed

    Barrow, Eric; Nicola, Anthony V; Liu, Jin

    2013-06-05

    Most viruses take advantage of endocytic pathways to gain entry into host cells and initiate infections. Understanding of virus entry via endocytosis is critically important for the design of antiviral strategies. Virus entry via endocytosis is a complex process involving hundreds of cellular proteins. The entire process is dictated by events occurring at multiple time and length scales. In this review, we discuss and evaluate the available means to investigate virus endocytic entry, from both experimental and theoretical/numerical modeling fronts, and highlight the importance of multiscale features. The complexity of the process requires investigations at a systems biology level, which involves the combination of different experimental approaches, the collaboration of experimentalists and theorists across different disciplines, and the development of novel multiscale models.

  4. Electrosteric stabilization of heteroflocculating suspensions and its application to the processing of self-compacting engineered cementitious composites

    NASA Astrophysics Data System (ADS)

    Kong, Hyun-Joon

    This dissertation investigates a dispersion/stabilization technique to improve the fluidity of heteroflocculating concentrated suspensions, and applies the technique to develop self-compacting Engineered Cementitious Composites (ECC), defined as a cementitious material which compacts without any external consolidation in the fresh state, while exhibiting strain-hardening performance in the hardened state. To meet the criteria of micromechanical design to achieve the ductile performance and processing design to attain high fluidity, this work has focused on preparing cement suspensions with low viscosity and high cohesiveness at a particle loading determined by the micromechanical design. Therefore, the goal of this work is to quantify how to adjust the strong flocculation between cement particles due to electrostatic and van der Waals attractive forces. For this purpose, a strong polyelectrolyte, melamine formaldehyde sulfonate (MFS), to disperse the oppositely-charged particles present in the cement dispersion, is combined with a non-ionic polymer, hydroxypropylmethylcellulose (HPMC). The combination of these two polymers to prevent re-flocculation leads to "complementary electrosteric dispersion/ stabilization". With these polymers, suspensions with the desired fluidity for processing are obtained. To quantify the roles of the two polymers in imparting stability, a heteroflocculating model suspension was developed, which facilitates the control of the interactions typical of cement suspensions, but without irreversible hydration. This model suspension is composed of alumina and silica particles, which bear surface potentials of opposite sign at intermediate pHs, as well as has a comparable magnitude of the Hamaker constant as compared to cement particles. As a result, the model system displays not only van der Waals attraction but also electrostatic attraction between dissimilar particles. Rheological studies of the model system stabilized by MFS and HPMC show

  5. Final Report - Assessment of Potential Phosphate Ion-Cementitious Materials Interactions

    SciTech Connect

    Naus, Dan J; Mattus, Catherine H; Dole, Leslie Robert

    2007-06-01

    The objectives of this limited study were to: (1) review the potential for degradation of cementitious materials due to exposure to high concentrations of phosphate ions; (2) provide an improved understanding of any significant factors that may lead to a requirement to establish exposure limits for concrete structures exposed to soils or ground waters containing high levels of phosphate ions; (3) recommend, as appropriate, whether a limitation on phosphate ion concentration in soils or ground water is required to avoid degradation of concrete structures; and (4) provide a "primer" on factors that can affect the durability of concrete materials and structures in nuclear power plants. An assessment of the potential effects of phosphate ions on cementitious materials was made through a review of the literature, contacts with concrete research personnel, and conduct of a "bench-scale" laboratory investigation. Results of these activities indicate that: no harmful interactions occur between phosphates and cementitious materials unless phosphates are present in the form of phosphoric acid; phosphates have been incorporated into concrete as set retarders, and phosphate cements have been used for infrastructure repair; no standards or guidelines exist pertaining to applications of reinforced concrete structures in high-phosphate environments; interactions of phosphate ions and cementitious materials has not been a concern of the research community; and laboratory results indicate similar performance of specimens cured in phosphate solutions and those cured in a calcium hydroxide solution after exposure periods of up to eighteen months. Relative to the "primer," a separate NUREG report has been prepared that provides a review of pertinent factors that can affect the durability of nuclear power plant reinforced concrete structures.

  6. Evaluation of natural colonisation of cementitious materials: effect of bioreceptivity and environmental conditions.

    PubMed

    Manso, Sandra; Calvo-Torras, María Ángeles; De Belie, Nele; Segura, Ignacio; Aguado, Antonio

    2015-04-15

    Incorporation of living organisms, such as photosynthetic organisms, on the structure envelope has become a priority in the area of architecture and construction due to aesthetical, economic and ecological advantages. Important research efforts are made to achieve further improvements, such as for the development of cementitious materials with an enhanced bioreceptivity to stimulate biological growth. Previously, the study of the bioreceptivity of cementitious materials has been carried out mainly under laboratory conditions although field-scale experiments may present different results. This work aims at analysing the colonisation of cementitious materials with different levels of bioreceptivity by placing them in three different environmental conditions. Specimens did not present visual colonisation, which indicates that environmental conditions have a greater impact than intrinsic properties of the material at this stage. Therefore, it appears that in addition to an optimized bioreceptivity of the concrete (i.e., composition, porosity and roughness), extra measures are indispensable for a rapid development of biological growth on concrete surfaces. An analysis of the colonisation in terms of genus and quantity of the most representative microorganisms found on the specimens for each location was carried out and related to weather conditions, such as monthly average temperature and total precipitation, and air quality in terms of NOx, SO2, CO and O3. OPC-based specimens presented a higher colonisation regarding both biodiversity and quantity. However, results obtained in a previous experimental programme under laboratory conditions suggested a higher suitability of Magnesium Phosphate Cement-based (MPC-based) specimens for algal growth. Consequently, carefully considering the environment and the relationships between the different organisms present in an environment is vital for successfully using a cementitious material as a substrate for biological growth

  7. Multiscale macromolecular simulation: role of evolving ensembles.

    PubMed

    Singharoy, A; Joshi, H; Ortoleva, P J

    2012-10-22

    Multiscale analysis provides an algorithm for the efficient simulation of macromolecular assemblies. This algorithm involves the coevolution of a quasiequilibrium probability density of atomic configurations and the Langevin dynamics of spatial coarse-grained variables denoted order parameters (OPs) characterizing nanoscale system features. In practice, implementation of the probability density involves the generation of constant OP ensembles of atomic configurations. Such ensembles are used to construct thermal forces and diffusion factors that mediate the stochastic OP dynamics. Generation of all-atom ensembles at every Langevin time step is computationally expensive. Here, multiscale computation for macromolecular systems is made more efficient by a method that self-consistently folds in ensembles of all-atom configurations constructed in an earlier step, history, of the Langevin evolution. This procedure accounts for the temporal evolution of these ensembles, accurately providing thermal forces and diffusions. It is shown that efficiency and accuracy of the OP-based simulations is increased via the integration of this historical information. Accuracy improves with the square root of the number of historical timesteps included in the calculation. As a result, CPU usage can be decreased by a factor of 3-8 without loss of accuracy. The algorithm is implemented into our existing force-field based multiscale simulation platform and demonstrated via the structural dynamics of viral capsomers.

  8. Multiscale stochastic approach for phase screens synthesis

    NASA Astrophysics Data System (ADS)

    Beghi, Alessandro; Cenedese, Angelo; Masiero, Andrea

    2011-07-01

    Simulating the turbulence effect on ground telescope observations is of fundamental importance for the design and test of suitable control algorithms for adaptive optics systems. In this paper we propose a multiscale approach for efficiently synthesizing turbulent phases at very high resolution. First, the turbulence is simulated at low resolution, taking advantage of a previously developed method for generating phase screens [J. Opt. Soc. Am. A25, 515 (2008)JOAOD60740-323210.1364/JOSAA.25.000515]. Then, high-resolution phase screens are obtained as the output of a multiscale linear stochastic system. The multiscale approach significantly improves the computational efficiency of turbulence simulation with respect to recently developed methods [Opt. Express14, 988 (2006)OPEXFF1094-408710.1364/OE.14.000988] [J. Opt. Soc. Am. A25, 515 (2008)JOAOD60740-323210.1364/JOSAA.25.000515] [J. Opt. Soc. Am. A25, 463 (2008)10.1364/JOSAA.25.000463JOAOD60740-3232]. Furthermore, the proposed procedure ensures good accuracy in reproducing the statistical characteristics of the turbulent phase.

  9. Multiscale Macromolecular Simulation: Role of Evolving Ensembles

    PubMed Central

    Singharoy, A.; Joshi, H.; Ortoleva, P.J.

    2013-01-01

    Multiscale analysis provides an algorithm for the efficient simulation of macromolecular assemblies. This algorithm involves the coevolution of a quasiequilibrium probability density of atomic configurations and the Langevin dynamics of spatial coarse-grained variables denoted order parameters (OPs) characterizing nanoscale system features. In practice, implementation of the probability density involves the generation of constant OP ensembles of atomic configurations. Such ensembles are used to construct thermal forces and diffusion factors that mediate the stochastic OP dynamics. Generation of all-atom ensembles at every Langevin timestep is computationally expensive. Here, multiscale computation for macromolecular systems is made more efficient by a method that self-consistently folds in ensembles of all-atom configurations constructed in an earlier step, history, of the Langevin evolution. This procedure accounts for the temporal evolution of these ensembles, accurately providing thermal forces and diffusions. It is shown that efficiency and accuracy of the OP-based simulations is increased via the integration of this historical information. Accuracy improves with the square root of the number of historical timesteps included in the calculation. As a result, CPU usage can be decreased by a factor of 3-8 without loss of accuracy. The algorithm is implemented into our existing force-field based multiscale simulation platform and demonstrated via the structural dynamics of viral capsomers. PMID:22978601

  10. MULTISCALE THERMOHYDROLOGIC MODEL

    SciTech Connect

    T. Buscheck

    2005-07-07

    The intended purpose of the multiscale thermohydrologic model (MSTHM) is to predict the possible range of thermal-hydrologic conditions, resulting from uncertainty and variability, in the repository emplacement drifts, including the invert, and in the adjoining host rock for the repository at Yucca Mountain. The goal of the MSTHM is to predict a reasonable range of possible thermal-hydrologic conditions within the emplacement drift. To be reasonable, this range includes the influence of waste-package-to-waste-package heat output variability relevant to the license application design, as well as the influence of uncertainty and variability in the geologic and hydrologic conditions relevant to predicting the thermal-hydrologic response in emplacement drifts. This goal is quite different from the goal of a model to predict a single expected thermal-hydrologic response. As a result, the development and validation of the MSTHM and the associated analyses using this model are focused on the goal of predicting a reasonable range of thermal-hydrologic conditions resulting from parametric uncertainty and waste-package-to-waste-package heat-output variability. Thermal-hydrologic conditions within emplacement drifts depend primarily on thermal-hydrologic conditions in the host rock at the drift wall and on the temperature difference between the drift wall and the drip-shield and waste-package surfaces. Thus, the ability to predict a reasonable range of relevant in-drift MSTHM output parameters (e.g., temperature and relative humidity) is based on valid predictions of thermal-hydrologic processes in the host rock, as well as valid predictions of heat-transfer processes between the drift wall and the drip-shield and waste-package surfaces. Because the invert contains crushed gravel derived from the host rock, the invert is, in effect, an extension of the host rock, with thermal and hydrologic properties that have been modified by virtue of the crushing (and the resulting

  11. Oscillations and multiscale dynamics in a closed chemical reaction system: second law of thermodynamics and temporal complexity.

    PubMed

    Li, Yongfeng; Qian, Hong; Yi, Yingfei

    2008-10-21

    We investigate the oscillatory reaction dynamics in a closed isothermal chemical system: the reversible Lotka-Volterra model. The second law of thermodynamics dictates that the system ultimately reaches an equilibrium. Quasistationary oscillations are analyzed while the free energy of the system serves as a global Lyapunov function of the dissipative dynamics. A natural distinction between regions near and far from equilibrium in terms of the free energy can be established. The dynamics is analogous to a nonlinear mechanical system with time-dependent increasing damping. Near equilibrium, no oscillation is possible as dictated by Onsager's reciprocal symmetry relation. We observe that while the free energy decreases in the closed system's dynamics, it does not follow the steepest descending path.

  12. Experimental Study on Mechanical Properties and Porosity of Organic Microcapsules Based Self-Healing Cementitious Composite.

    PubMed

    Wang, Xianfeng; Sun, Peipei; Han, Ningxu; Xing, Feng

    2017-01-01

    Encapsulation of healing agents embedded in a material matrix has become one of the major approaches for achieving self-healing function in cementitious materials in recent years. A novel type of microcapsules based self-healing cementitious composite was developed in Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University. In this study, both macro performance and the microstructure of the composite are investigated. The macro performance was evaluated by employing the compressive strength and the dynamic modulus, whereas the microstructure was represented by the pore structure parameters such as porosity, cumulative-pore volume, and average-pore diameter, which are significantly correlated to the pore-size distribution and the compressive strength. The results showed that both the compressive strength and the dynamic modulus, as well as the pore structure parameters such as porosity, cumulative-pore volume, and average-pore diameter of the specimen decrease to some extent with the amount of microcapsules. However, the self-healing rate and the recovery rate of the specimen performance and the pore-structure parameters increase with the amount of microcapsules. The results should confirm the self-healing function of microcapsules in the cementitious composite from macroscopic and microscopic viewpoints.

  13. Experimental Study on Mechanical Properties and Porosity of Organic Microcapsules Based Self-Healing Cementitious Composite

    PubMed Central

    Wang, Xianfeng; Sun, Peipei; Han, Ningxu; Xing, Feng

    2017-01-01

    Encapsulation of healing agents embedded in a material matrix has become one of the major approaches for achieving self-healing function in cementitious materials in recent years. A novel type of microcapsules based self-healing cementitious composite was developed in Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University. In this study, both macro performance and the microstructure of the composite are investigated. The macro performance was evaluated by employing the compressive strength and the dynamic modulus, whereas the microstructure was represented by the pore structure parameters such as porosity, cumulative-pore volume, and average-pore diameter, which are significantly correlated to the pore-size distribution and the compressive strength. The results showed that both the compressive strength and the dynamic modulus, as well as the pore structure parameters such as porosity, cumulative-pore volume, and average-pore diameter of the specimen decrease to some extent with the amount of microcapsules. However, the self-healing rate and the recovery rate of the specimen performance and the pore-structure parameters increase with the amount of microcapsules. The results should confirm the self-healing function of microcapsules in the cementitious composite from macroscopic and microscopic viewpoints. PMID:28772382

  14. Micromechanical Properties of a New Polymeric Microcapsule for Self-Healing Cementitious Materials

    PubMed Central

    Lv, Leyang; Schlangen, Erik; Yang, Zhengxian; Xing, Feng

    2016-01-01

    Self-healing cementitious materials containing a microencapsulated healing agent are appealing due to their great application potential in improving the serviceability and durability of concrete structures. In this study, poly(phenol–formaldehyde) (PF) microcapsules that aim to provide a self-healing function for cementitious materials were prepared by an in situ polymerization reaction. Size gradation of the synthesized microcapsules was achieved through a series of sieving processes. The shell thickness and the diameter of single microcapsules was accurately measured under environmental scanning electron microscopy (ESEM). The relationship between the physical properties of the synthesized microcapsules and their micromechanical properties were investigated using nanoindentation. The results of the mechanical tests show that, with the increase of the mean size of microcapsules and the decrease of shell thickness, the mechanical force required to trigger the self-healing function of microcapsules increased correspondingly from 68.5 ± 41.6 mN to 198.5 ± 31.6 mN, featuring a multi-sensitive trigger function. Finally, the rupture behavior and crack surface of cement paste with embedded microcapsules were observed and analyzed using X-ray computed tomography (XCT). The synthesized PF microcapsules may find potential application in self-healing cementitious materials. PMID:28774144

  15. Use of polypropylene fibers coated with nano-silica particles into a cementitious mortar

    SciTech Connect

    Coppola, B. Di Maio, L.; Scarfato, P.; Incarnato, L.

    2015-12-17

    Fiber reinforced cementitious composite (FRCC) materials have been widely used during last decades in order to overcome some of traditional cementitious materials issues: brittle behaviour, fire resistance, cover spalling, impact strength. For composite materials, fiber/matrix bond plays an important role because by increasing fiber/matrix interactions is possible to increase the behaviour of the entire material. In this study, in order to improve fiber to matrix adhesion, two chemical treatments of polypropylene fibers were investigated: alkaline hydrolysis and nano-silica sol-gel particles deposition. Treatmtents effect on fibers morphology and mechanical properties was investigated by scanning electron microscopy (SEM) and tensile tests. SEM investigations report the presence of spherical nano-silica particles on fiber surface, in the case of sol-gel process, while alkaline hydrolysis leads to an increase of fibers roughness. Both treatments have negligible influence on fibers mechanical properties confirming the possibility of their use in a cementitious mortar. Pullout tests were carried out considering three embedded length of fibers in mortar samples (10, 20 and 30 mm, respectively) showing an increase of pullout energy for treated fibers. The influence on fiber reinforced mortar mechanical properties was investigated by three-point flexural tests on prismatic specimens considering two fibers length (15 and 30 mm) and two fibers volume fractions (0.50 and 1.00 %). A general increase of flexural strength over the reference mix was achieved and an overall better behaviour is recognizable for mortars containing treated fibers.

  16. Shock Wave Propagation in Cementitious Materials at Micro/Meso Scales

    NASA Astrophysics Data System (ADS)

    Rajendran, Arunachalam

    2015-06-01

    The mechanical and constitutive response of materials like cement, and bio materials like fish scale and abalone shell is very complex due to heterogeneities that are inherently present in the nano and microstructures. The intrinsic constitutive behaviors are driven by the chemical composition and the molecular, micro, and meso structures. Therefore, it becomes important to identify the material genome as the building block for the material. For instance, in cementitious materials, the genome of C-S-H phase (the glue or the paste) that holds the various clinkers, such as the dicalcium silicate, tricalcium silicate, calcium ferroaluminates, and others is extremely complex. Often mechanical behaviors of C-S-H type materials are influenced by the chemistry and the structures at all nano to micro length scales. By explicitly modeling the molecular structures using appropriate potentials, it is then possible to compute the elastic tensor from molecular dynamics simulations using all atom method. The elastic tensors for the C-S-H gel and other clinkers are determined using the software suite ``Accelrys Materials Studio.'' A strain rate dependent, fracture mechanics based tensile damage model has been incorporated into ABAQUS finite element code to model spall evolution in the heterogeneous cementitious material with all constituents explicitly modeled through one micron element resolution. This paper presents results from nano/micro/meso scale analyses of shock wave propagation in a heterogeneous cementitious material using both molecular dynamic and finite element codes.

  17. Use of polypropylene fibers coated with nano-silica particles into a cementitious mortar

    NASA Astrophysics Data System (ADS)

    Coppola, B.; Di Maio, L.; Scarfato, P.; Incarnato, L.

    2015-12-01

    Fiber reinforced cementitious composite (FRCC) materials have been widely used during last decades in order to overcome some of traditional cementitious materials issues: brittle behaviour, fire resistance, cover spalling, impact strength. For composite materials, fiber/matrix bond plays an important role because by increasing fiber/matrix interactions is possible to increase the behaviour of the entire material. In this study, in order to improve fiber to matrix adhesion, two chemical treatments of polypropylene fibers were investigated: alkaline hydrolysis and nano-silica sol-gel particles deposition. Treatmtents effect on fibers morphology and mechanical properties was investigated by scanning electron microscopy (SEM) and tensile tests. SEM investigations report the presence of spherical nano-silica particles on fiber surface, in the case of sol-gel process, while alkaline hydrolysis leads to an increase of fibers roughness. Both treatments have negligible influence on fibers mechanical properties confirming the possibility of their use in a cementitious mortar. Pullout tests were carried out considering three embedded length of fibers in mortar samples (10, 20 and 30 mm, respectively) showing an increase of pullout energy for treated fibers. The influence on fiber reinforced mortar mechanical properties was investigated by three-point flexural tests on prismatic specimens considering two fibers length (15 and 30 mm) and two fibers volume fractions (0.50 and 1.00 %). A general increase of flexural strength over the reference mix was achieved and an overall better behaviour is recognizable for mortars containing treated fibers.

  18. Micromechanical Properties of a New Polymeric Microcapsule for Self-Healing Cementitious Materials.

    PubMed

    Lv, Leyang; Schlangen, Erik; Yang, Zhengxian; Xing, Feng

    2016-12-20

    Self-healing cementitious materials containing a microencapsulated healing agent are appealing due to their great application potential in improving the serviceability and durability of concrete structures. In this study, poly(phenol-formaldehyde) (PF) microcapsules that aim to provide a self-healing function for cementitious materials were prepared by an in situ polymerization reaction. Size gradation of the synthesized microcapsules was achieved through a series of sieving processes. The shell thickness and the diameter of single microcapsules was accurately measured under environmental scanning electron microscopy (ESEM). The relationship between the physical properties of the synthesized microcapsules and their micromechanical properties were investigated using nanoindentation. The results of the mechanical tests show that, with the increase of the mean size of microcapsules and the decrease of shell thickness, the mechanical force required to trigger the self-healing function of microcapsules increased correspondingly from 68.5 ± 41.6 mN to 198.5 ± 31.6 mN, featuring a multi-sensitive trigger function. Finally, the rupture behavior and crack surface of cement paste with embedded microcapsules were observed and analyzed using X-ray computed tomography (XCT). The synthesized PF microcapsules may find potential application in self-healing cementitious materials.

  19. Multi-scale First-Principles Modeling of Three-Phase System of Polymer Electrolyte Membrane Fuel Cel

    SciTech Connect

    Brunello, Giuseppe; Choi, Ji; Harvey, David; Jang, Seung

    2012-07-01

    The three-phase system consisting of Nafion, graphite and platinum in the presence of water is studied using molecule dynamics simulation. The force fields describing the molecular interaction between the components in the system are developed to reproduce the energies calculated from density functional theory modeling. The configuration of such complicated three-phase system is predicted through MD simulations. The nanophase-segregation and transport properties are investigated from the equilibrium state. The coverage of the electrolyte on the platinum surface and the dissolution of oxygen are analyzed.

  20. Taylor-Aris Dispersion: An Explicit Example for Understanding Multiscale Analysis via Volume Averaging

    ERIC Educational Resources Information Center

    Wood, Brian D.

    2009-01-01

    Although the multiscale structure of many important processes in engineering is becoming more widely acknowledged, making this connection in the classroom is a difficult task. This is due in part because the concept of multiscale structure itself is challenging and it requires the students to develop new conceptual pictures of physical systems,…

  1. Performance and diagnostic evaluation of ozone predictions by the Eta-Community Multiscale Air Quality Forecast System during the 2002 New England Air Quality Study.

    PubMed

    Yu, Shaocai; Mathur, Rohit; Kang, Daiwen; Schere, Kenneth; Eder, Brian; Pleim, Jonathan

    2006-10-01

    A real-time air quality forecasting system (Eta-Community Multiscale Air Quality [CMAQ] model suite) has been developed by linking the National Centers for Environmental Estimation Eta model to the U.S. Environmental Protection Agency (EPA) CMAQ model. This work presents results from the application of the Eta-CMAQ modeling system for forecasting ozone (O3) over the Northeastern United States during the 2002 New England Air Quality Study (NEAQS). Spatial and temporal performance of the Eta-C