DEFF Research Database (Denmark)
Madsen, Jens
2013-01-01
variables. The fluid moment hierarchy is closed by approximating the gyrokinetic distribution function as a finite order Hermite-Laguerre polynomial and by determining closure approximations for terms involving the gyrokinetic gyro-averaging operator. The model exactly conserves the gyrokinetic full......-F energy invariant evaluated using the Hermite-Laguerre decomposition. The model is suited for qualitative studies of the interplay between turbulence, flows, and dynamically evolving profiles in magnetically confined plasmas....
Directory of Open Access Journals (Sweden)
Kátia Lúcia Pacheco
2015-11-01
Full Text Available Objective. This article aims at identifying the genesis of the studies the conceptual model Functional Requirements for Bibliographic Records (FRBR, published in 1998 by the International Federation of Library Associations and Institutions (IFLA with the proposal to develop new approach to the bibliographic record. Method. For this appealed to bibliographical research, primarily the sources of official information IFLA, in order to investigate the trajectory preceding the publication of the model and determine the intellectual debate on its elaboration. Results. It was found that the FRBR model was born with eminently practical purposes and generates a set of expectations about the reduction of cataloging costs, indicating a minimum level element in bibliographic records that meet the needs of the users associated with the various types of materials and contexts of use. Conclusions. The accumulation of scientific knowledge coupled with sustained and brought experiential dimension in the model, changes the paradigms of traditional cataloging, but model the final report does not present the foundations that support it.
Full sequence analysis of the original Sapporo virus.
Nakanishi, Kaori; Tatsumi, Masatoshi; Kinoshita-Numata, Kazuko; Tsugawa, Takeshi; Nakata, Shuji; Tsutsumi, Hiroyuki
2011-09-01
In this study, the full-length genome sequence of the prototype of sapovirus, namely Sapporo virus (SV82), was identified. Sapporo virus RNA was extracted from a fecal sample, amplified by RT-PCR and the PCR products sequenced directly and analyzed. Sequence analysis showed that Sapporo virus consists of 7433 nucleotides and has three open reading frames. The Sapporo strain shows 91.7% nucleotide sequence identity to the Manchester virus. Phylogenic analysis has also revealed the closeness of Sapporo virus to other sapovirus/genogroup I strains. Basic information on the evolutionary history of sapovirus analysis is provided here.
Mesoscopic full counting statistics and exclusion models
Roche, P.-E.; Derrida, B.; Douçot, B.
2005-02-01
We calculate the distribution of current fluctuations in two simple exclusion models. Although these models are classical, we recover even for small systems such as a simple or a double barrier, the same distibution of current as given by traditional formalisms for quantum mesoscopic conductors. Due to their simplicity, the full counting statistics in exclusion models can be reduced to the calculation of the largest eigenvalue of a matrix, the size of which is the number of internal configurations of the system. As examples, we derive the shot noise power and higher order statistics of current fluctuations (skewness, full counting statistics, ....) of various conductors, including multiple barriers, diffusive islands between tunnel barriers and diffusive media. A special attention is dedicated to the third cumulant, which experimental measurability has been demonstrated lately.
1929-01-01
Model of Full-Scale Tunnel (FST) under construction. On June 26, 1929, Elton W. Miller wrote to George W. Lewis proposing the construction of a model of the full-scale tunnel . 'The excellent energy ratio obtained in the new wind tunnel of the California Institute of Technology suggests that before proceeding with our full scale tunnel design, we ought to investigate the effect on energy ratio of such factors as: 1. Small included angle for the exit cone; 2. Carefully designed return passages of circular section as far as possible, without sudden changes in cross sections; 3. Tightness of walls. It is believed that much useful information can be obtained by building a model of about 1/16 scale, that is, having a closed throat of 2 ft. by 4 ft. The outside dimensions would be about 12 ft. by 25 ft. in plan and the height 4 ft. Two propellers will be required about 28 in. in diameter, each to be driven by direct current motor at a maximum speed of 4500 R.P.M. Provision can be made for altering the length of certain portions, particularly the exit cone, and possibly for the application of boundary layer control in order to effect satisfactory air flow. This model can be constructed in a comparatively short time, using 2 by 4 framing with matched sheathing inside, and where circular sections are desired they can be obtained by nailing sheet metal to wooden ribs, which can be cut on the band saw. It is estimated that three months will be required for the construction and testing of such a model and that the cost will be approximately three thousand dollars, one thousand dollars of which will be for the motors. No suitable location appears to exist in any of our present buildings, and it may be necessary to build it outside and cover it with a roof.' George Lewis responded immediately (June 27) granting the authority to proceed. He urged Langley to expedite construction and to employ extra carpenters if necessary. Funds for the model came from the FST project. In a 1979
A Full Disturbance Model for Reaction Wheels
Le, M.P.; Ellenbroek, Marcellinus Hermannus Maria; Seiler, R; van Put, P.; Cottaar, E.J.E.
2014-01-01
Reaction wheels are rotating devices used for the attitude control of spacecraft. However, reaction wheels also generate undesired disturbances in the form of vibrations, which may have an adverse effect on the pointing accuracy and stability of spacecraft (optical) payloads. A disturbance model for
Full-Scale Cookoff Model Validation Experiments
Energy Technology Data Exchange (ETDEWEB)
McClelland, M A; Rattanapote, M K; Heimdahl, E R; Erikson, W E; Curran, P O; Atwood, A I
2003-11-25
This paper presents the experimental results of the third and final phase of a cookoff model validation effort. In this phase of the work, two generic Heavy Wall Penetrators (HWP) were tested in two heating orientations. Temperature and strain gage data were collected over the entire test period. Predictions for time and temperature of reaction were made prior to release of the live data. Predictions were comparable to the measured values and were highly dependent on the established boundary conditions. Both HWP tests failed at a weld located near the aft closure of the device. More than 90 percent of unreacted explosive was recovered in the end heated experiment and less than 30 percent recovered in the side heated test.
The Halo Model of Origin Images
DEFF Research Database (Denmark)
Josiassen, Alexander; Lukas, Bryan A.; Whitwell, Gregory J.
2013-01-01
National origin has gained importance as a marketing tool for practitioners to sell their goods and services. However, because origin-image research has been troubled by several fundamental limitations, academia has become sceptical of the current status and strategic implications of the concept....... The aim of this paper was threefold, namely, to provide a state-of-the-art review of origin-image research in marketing, develop and empirically test a new origin-image model and, present the implications of the study....
Modeling liquid hydrogen cavitating flow with the full cavitation model
Energy Technology Data Exchange (ETDEWEB)
Zhang, X.B.; Qiu, L.M.; Qi, H.; Zhang, X.J.; Gan, Z.H. [Institute of Refrigeration and Cryogenic Engineering, Zhejiang University, Hangzhou 310027 (China)
2008-12-15
Cavitation is the formation of vapor bubbles within a liquid where flow dynamics cause the local static pressure to drop below the vapor pressure. This paper strives towards developing an effective computational strategy to simulate liquid hydrogen cavitation relevant to liquid rocket propulsion applications. The aims are realized by performing a steady state computational fluid dynamic (CFD) study of liquid hydrogen flow over a 2D hydrofoil and an axisymmetric ogive in Hord's reports with a so-called full cavitation model. The thermodynamic effect was demonstrated with the assumption of thermal equilibrium between the gas phase and liquid phase. Temperature-dependent fluid thermodynamic properties were specified along the saturation line from the ''Gaspak 3.2'' databank. Justifiable agreement between the computed surface pressure, temperature and experimental data of Hord was obtained. Specifically, a global sensitivity analysis is performed to examine the sensitivity of the turbulent computations to the wall grid resolution, wall treatments and changes in model parameters. A proper near-wall model and grid resolution were suggested. The full cavitation model with default model parameters provided solutions with comparable accuracy to sheet cavitation in liquid hydrogen for the two geometries. (author)
Origin of energetic ions observed in the terrestrial ion foreshock : 2D full-particle simulations
Savoini, Philippe; Lembege, bertrand
2016-04-01
Collisionless shocks are well-known structures in astrophysical environments which dissipate bulk flow kinetic energy and accelerate large fraction of particle. Spacecrafts have firmly established the existence of the so-called terrestrial foreshock region magnetically connected to the shock and filled by two distinct populations in the quasi-perpendicular shock region (i.e. for 45r{ } ≤ quad θ Bn quad ≤ 90r{ }, where θ Bn is the angle between the shock normal and the upstream magnetic field) : (i) the field-aligned ion beams or `` FAB '' characterized by a gyrotropic distributionsout{,} and (ii) the gyro-phase bunched ions or `` GPB '' characterized by a NON gyrotropic distribution. The present work is based on the use of two dimensional PIC simulation of a curved shock and associated foreshock region where full curvature effects, time of flight effects and both electrons and ions dynamics are fully described by a self consistent approach. Our previous analysis (Savoini et Lembège, 2015) has evidenced that these two types of backstreaming populations can originate from the shock front itself without invoking any local diffusion by ion beam instabilities. Present results are focussed on individual ion trajectories and evidence that "FAB" population is injected into the foreshock mainly along the shock front whereas the "GPB" population penetrates more deeply the shock front. Such differences explain why the "FAB" population loses their gyro-phase coherency and become gyrotropic which is not the case for the "GPB". The impact of these different injection features on the energy gain for each ion population will be presented in détails. Savoini, P. and B. Lembège (2015), `` Production of nongyrotropic and gyrotropic backstreaming ion distributions in the quasi-perpendicular ion foreshock région '', J. Geophys. Res., 120, pp 7154-7171, doi = 10.1002/2015JA021018.
Standardized Tests and Froebel's Original Kindergarten Model
Jeynes, William H.
2006-01-01
The author argues that American educators rely on standardized tests at too early an age when administered in kindergarten, particularly given the original intent of kindergarten as envisioned by its founder, Friedrich Froebel. The author examines the current use of standardized tests in kindergarten and the Froebel model, including his emphasis…
A full lifecycle bioenergetic model for bluefin tuna.
Marko Jusup; Tin Klanjscek; Hiroyuki Matsuda; Kooijman, S.A.L.M.
2011-01-01
We formulated a full lifecycle bioenergetic model for bluefin tuna relying on the principles of Dynamic Energy Budget theory. Traditional bioenergetic models in fish research deduce energy input and utilization from observed growth and reproduction. In contrast, our model predicts growth and reproduction from food availability and temperature in the environment. We calibrated the model to emulate physiological characteristics of Pacific bluefin tuna (Thunnus orientalis, hereafter PBT), a spec...
El Salvador - Education Quality, Full-Time Inclusive Model
Millennium Challenge Corporation — Mathematica Policy Research (MPR) was contracted by MCC to conduct an impact evaluation of the Integrated Systems of Full-Time Inclusive Schools model (SI-EITP for...
Towards integrated modelling: full image simulations for WEAVE
Dalton, Gavin; Ham, Sun Jeong; Trager, Scott; Abrams, Don Carlos; Bonifacio, Piercarlo; Aguerri, J. A. L.; Middleton, Kevin; Benn, Chris; Rogers, Kevin; Stuik, Remko; Carrasco, Esperanza; Vallenari, Antonella; Jin, Shoko; Lewis, Jim
2016-08-01
We present an integrated end-end simulation of the spectral images that will be obtained by the weave spectrograph, which aims to include full modelling of all effects from the top of the atmosphere to the detector. These data are based in input spectra from a combination of library spectra and synthetic models, and will be used to provide inputs for an endend test of the full weave data pipeline and archive systems, prior to 1st light of the instrument.
Full feature data model for spatial information network integration
Institute of Scientific and Technical Information of China (English)
DENG Ji-qiu; BAO Guang-shu
2006-01-01
In allusion to the difficulty of integrating data with different models in integrating spatial information,the characteristics of raster structure, vector structure and mixed model were analyzed, and a hierarchical vectorraster integrative full feature model was put forward by integrating the advantage of vector and raster model and using the object-oriented method. The data structures of the four basic features, i.e. point, line, surface and solid,were described. An application was analyzed and described, and the characteristics of this model were described. In this model, all objects in the real world are divided into and described as features with hierarchy, and all the data are organized in vector. This model can describe data based on feature, field, network and other models, and avoid the disadvantage of inability to integrate data based on different models and perform spatial analysis on them in spatial information integration.
Digital modeling technology for full dental crown tooth preparation.
Dai, Ning; Zhong, Yicheng; Liu, Hao; Yuan, Fusong; Sun, Yuchun
2016-04-01
A dental defect is one of the most common oral diseases, and it often requires a full crown restoration. In this clinical operation, the dentist must manually prepare the affected tooth for the full crown so that it has a convergence angle between 4° and 10°, no undercuts, and uniform and even shoulder widths and depths using a high speed diamond bur in the patient׳s mouth within one hour, which is a difficult task that requires visual-manual operation. The quality of the tooth preparation has an important effect on the success rate of the subsequent prosthodontic treatment. This study involved research into digital modeling technology for full dental crown tooth preparation. First, the margin line of the tooth preparation was designed using a semi-automatic interactive process. Second, the inserting direction was automatically computed. Then, the characteristic parameters and the constraints on the tooth preparation were defined for the model. Next, the shoulder and axial surface of the tooth preparation were formed using parametric modeling. Finally, the implicit surface of a radial basis function was used to construct the tooth preparation׳s occlusal surface. The experimental results verified that the method of digital modeling for full crown preparation proposed in this study can quickly and accurately implement personalized designs of various parameters, such as the shoulder width and the convergence angle; it provides a digital design tool for full crown preparation.
CONVERSE REASONING FOR FULL DEPRESSION-FEATURE MODEL AND PROCESS
Institute of Scientific and Technical Information of China (English)
无
2003-01-01
A new approach, namely, "defining protrusion-feature with depression-parameter" is advanced, which focuses on the shortcomings of protrusion-feature alteration method; The full depression-feature model is built up, and a basic converse reasoning iterative algorithm for machining process is given.The detailed examination has been implemented on the feature-based modeling system for light industry product (QJFMS) and the converse reasoning on fixture-based machining process is achieved.
Full-Range Mathematical Modeling of Turboshaft Engine in Aerospace
Sheng, Hanlin; Zhang, Tianhong; Jiang, Wei
2016-12-01
In this paper, an approximate computation method of low-speed component characteristics in aeroengine is used and full-range component characteristics is obtained by combining experimental data above idle. Moreover, based on components matching method and variable specific heat method, a full-range static and dynamic mathematical model of turboshaft engine is built, including start-up state. And the numerical simulation result of the engine whole working process is also showed in this paper. The comparison result between the simulation result and the experimental data shows that, the full-range model built by the computation method of low-speed component characteristics is of a certain accuracy, which can meet the needs of a turboshaft engine semi-physical simulation.
Full-scale validation of a model of algal productivity.
Béchet, Quentin; Shilton, Andy; Guieysse, Benoit
2014-12-02
While modeling algal productivity outdoors is crucial to assess the economic and environmental performance of full-scale cultivation, most of the models hitherto developed for this purpose have not been validated under fully relevant conditions, especially with regard to temperature variations. The objective of this study was to independently validate a model of algal biomass productivity accounting for both light and temperature and constructed using parameters experimentally derived using short-term indoor experiments. To do this, the accuracy of a model developed for Chlorella vulgaris was assessed against data collected from photobioreactors operated outdoor (New Zealand) over different seasons, years, and operating conditions (temperature-control/no temperature-control, batch, and fed-batch regimes). The model accurately predicted experimental productivities under all conditions tested, yielding an overall accuracy of ±8.4% over 148 days of cultivation. For the purpose of assessing the feasibility of full-scale algal cultivation, the use of the productivity model was therefore shown to markedly reduce uncertainty in cost of biofuel production while also eliminating uncertainties in water demand, a critical element of environmental impact assessments. Simulations at five climatic locations demonstrated that temperature-control in outdoor photobioreactors would require tremendous amounts of energy without considerable increase of algal biomass. Prior assessments neglecting the impact of temperature variations on algal productivity in photobioreactors may therefore be erroneous.
A full annual cycle modeling framework for American black ducks
Robinson, Orin J.; McGowan, Conor; Devers, Patrick K.; Brook, Rodney W.; Huang, Min; Jones, Malcom; McAuley, Daniel G.; Zimmerman, Guthrie
2016-01-01
American black ducks (Anas rubripes) are a harvested, international migratory waterfowl species in eastern North America. Despite an extended period of restrictive harvest regulations, the black duck population is still below the population goal identified in the North American Waterfowl Management Plan (NAWMP). It has been hypothesized that density-dependent factors restrict population growth in the black duck population and that habitat management (increases, improvements, etc.) may be a key component of growing black duck populations and reaching the prescribed NAWMP population goal. Using banding data from 1951 to 2011 and breeding population survey data from 1990 to 2014, we developed a full annual cycle population model for the American black duck. This model uses the seven management units as set by the Black Duck Joint Venture, allows movement into and out of each unit during each season, and models survival and fecundity for each region separately. We compare model population trajectories with observed population data and abundance estimates from the breeding season counts to show the accuracy of this full annual cycle model. With this model, we then show how to simulate the effects of habitat management on the continental black duck population.
Microbubble Swarms in a Full-Scale Water Model Tundish
Chang, Sheng; Cao, Xiangkun; Zou, Zongshu; Isac, Mihaiela; Guthrie, Roderick I. L.
2016-10-01
Water modeling, using microbubble swarms, was performed in a full-scale, four-strand, delta-shaped tundish, located at the McGill Metals Processing Centre (MMPC). The objective of the study was to investigate the effectiveness of microbubbles in removing inclusions smaller than 50 μm, applying the principles and conditions previously researched using a smaller scale arrangement. Air was injected into a full-scale model of a ladle shroud (the connecting tube through which liquid steel flows into the tundish below). The model ladle shroud was fitted with twelve, laser-drilled orifices, so as to create microbubbles. The bubbles generated using different gas injection protocols were recorded using a high-speed camera, and the bubble images were postprocessed using the commercial software, ImageJ. With this newly designed ladle shroud, bubble sizes could be reduced dramatically, to as small as a 675 µm average diameter. A three-dimensional, CFD model simulation was developed, using parameters obtained from the corresponding water model experiments, in order to predict the behavior of these microbubbles within the tundish and their potential influence on flow patterns and inclusion float-out capability.
Validation of full cavitation model in cryogenic fluids
Institute of Scientific and Technical Information of China (English)
CAO XiaoLi; ZHANG XiaoBin; QIU LiMin; GAN ZhiHua
2009-01-01
Numerical simulation of cavitation in cryogenic fluids is important in improving the stable operation of he propulsion system in liquid-fuel rocket. It also represents a broader class of problems where the fluid is operating close to its critical point and the thermal effects of cavitation are pronounced. The present article focuses on simulating cryogenic cavitation by implementing the "full cavitation model", coupled with energy equation, in conjunction with iteraUve update of the real fluid properties at local temperatures. Steady state computations are then conducted on hydrofoil and ogive in liquid nitrogen and hydrogen respectively, based on which we explore the mechanism of cavitation with thermal ef-fects. Comprehensive comparisons between the simulation results and experimental data as well as previous computations by other researchers validate the full cavitation model in cryogenic fluids. The sensitivity of cavity length to cavitation number is also examined.
Comparative dynamic analysis of the full Grossman model.
Ried, W
1998-08-01
The paper applies the method of comparative dynamic analysis to the full Grossman model. For a particular class of solutions, it derives the equations implicitly defining the complete trajectories of the endogenous variables. Relying on the concept of Frisch decision functions, the impact of any parametric change on an endogenous variable can be decomposed into a direct and an indirect effect. The focus of the paper is on marginal changes in the rate of health capital depreciation. It also analyses the impact of either initial financial wealth or the initial stock of health capital. While the direction of most effects remains ambiguous in the full model, the assumption of a zero consumption benefit of health is sufficient to obtain a definite for any direct or indirect effect.
A New Vision Of Management: Full Potential Management Model
Directory of Open Access Journals (Sweden)
Yuka Fujimoto
2010-11-01
Full Text Available This paper establishes the Full Potential Management (FPM Model based upon the social model of disabilities coupled with principles of diversity management and disability-oriented human resource management. Despite the fact that the concept of management was once envisioned as having ‘value to society’ by improving the quality of life through efficient practices (Rimler, 1976, management literature has narrowly defined management as a means to gain increased productivity and achieve organizational goals, thus overlooking the social formation and implementation design for a better life (Diener & Seligman, 2004; Small, 2004; Whitley 1989. Based upon the diversity literature, we propose that social-oriented diversity management principles and practices are the key to transforming management concepts from achieving organizational potential to achieving social aims that maximize the potential and quality of life of each person.
A full lifecycle bioenergetic model for bluefin tuna.
Directory of Open Access Journals (Sweden)
Marko Jusup
Full Text Available We formulated a full lifecycle bioenergetic model for bluefin tuna relying on the principles of Dynamic Energy Budget theory. Traditional bioenergetic models in fish research deduce energy input and utilization from observed growth and reproduction. In contrast, our model predicts growth and reproduction from food availability and temperature in the environment. We calibrated the model to emulate physiological characteristics of Pacific bluefin tuna (Thunnus orientalis, hereafter PBT, a species which has received considerable scientific attention due to its high economic value. Computer simulations suggest that (i the main cause of different growth rates between cultivated and wild PBT is the difference in average body temperature of approximately 6.5°C, (ii a well-fed PBT individual can spawn an average number of 9 batches per spawning season, (iii food abundance experienced by wild PBT is rather constant and sufficiently high to provide energy for yearly reproductive cycle, (iv energy in reserve is exceptionally small, causing the weight-length relationship of cultivated and wild PBT to be practically indistinguishable and suggesting that these fish are poorly equipped to deal with starvation, (v accelerated growth rate of PBT larvae is connected to morphological changes prior to metamorphosis, while (vi deceleration of growth rate in the early juvenile stage is related to efficiency of internal heat production. Based on these results, we discuss a number of physiological and ecological traits of PBT, including the reasons for high Feed Conversion Ratio recorded in bluefin tuna aquaculture.
Chrominance watermark embed using a full-color visibility model
Bradley, Brett; Reed, Alastair; Stach, John
2012-03-01
A watermark embed scheme has been developed to insert a watermark with the maximum signal strength for a user selectable visibility constraint. By altering the watermark strength and direction to meet a visibility constraint, the maximum watermark signal for a particular image is inserted. The method consists of iterative embed software and a full color human visibility model plus a watermark signal strength metric. The iterative approach is based on the intersections between hyper-planes, which represent visibility and signal models, and the edges of a hyper-volume, which represent output device visibility and gamut constraints. The signal metric is based on the specific watermark modulation and detection methods and can be adapted to other modulation approaches. The visibility model takes into account the different contrast sensitivity functions of the human eye to L, a and b, and masking due to image content.
Full waveform modelling and misfit calculation using the VERCE platform
Garth, Thomas; Spinuso, Alessandro; Casarotti, Emanuele; Magnoni, Federica; Krischner, Lion; Igel, Heiner; Schwichtenberg, Horst; Frank, Anton; Vilotte, Jean-Pierre; Rietbrock, Andreas
2016-04-01
In recent years the increasing resolution of seismic imagining by full waveform inversion has opened new research perspectives and practices. These methods rely on harnessing the computational power of large supercomputers and new storage capabilities, to run large parallel codes to simulate the seismic wave field in three-dimensional geological settings. The VERCE platform is designed to make these full waveform techniques accessible to a far wider spectrum of the seismological community. VERCE empowers a broad base of seismology researchers to harvest the new opportunities provided by well-established high-performance wave simulation codes such as SPECFEM3D. It meets a range of seismic research needs by eliminating the technical difficulties associated with using these codes, allowing users to focus on their research questions. VERCE delivers this power to seismologists through its science gateway, supporting wave simulation codes on each of the provided computing resources. Users can design their waveform simulation scenarios making use of a library of pre-loaded meshes and velocity models, and services for selecting earthquake focal mechanisms, seismic stations and recorded waveforms from existing catalogues, such as the GCMT catalogue, and FDSN data sources. They can also supply their own mesh, velocity model, earthquake catalogue and seismic observations. They can submit the simulations onto different computing resources, where VERCE provides codes that are tuned and supported for those resources. The simulations can currently be run on a range of European supercomputers in the PRACE network, including superMUC at LRZ, GALILEO at CINECA and on selected resources like Drachenfels at SCAI and within the EGI network. The gateway automates and looks after all these stages, but supplies seismologists with a provenance system that allows them to manage a large series of runs, review progress, and explore the results. The platform automates misfit analysis between
Model of Full-Scale Tunnel (FST) under construction
1929-01-01
Model of Full-Scale Tunnel (FST) under construction. On June 26, 1929, Elton W. Miller wrote to George W. Lewis proposing the construction of a model of the full-scale tunnel. 'The excellent energy ratio obtained in the new wind tunnel of the California Institute of Technology suggests that before proceeding with our full scale tunnel design, we ought to investigate the effect on energy ratio of such factors as: 1. small included angle for the exit cone; 2. carefully designed return passages of circular section as far as possible, without sudden changes in cross sections; 3. tightness of walls. It is believed that much useful information can be obtained by building a model of about 1/16 scale, that is, having a closed throat of 2 ft. by 4 ft. The outside dimensions would be about 12 ft. by 25 ft. in plan and the height 4 ft. Two propellers will be required about 28 in. in diameter, each to be driven by direct current motor at a maximum speed of 4500 R.P.M. Provision can be made for altering the length of certain portions, particularly the exit cone, and possibly for the application of boundary layer control in order to effect satisfactory air flow. This model can be constructed in a comparatively short time, using 2 by 4 framing with matched sheathing inside, and where circular sections are desired they can be obtained by nailing sheet metal to wooden ribs, which can be cut on the band saw. It is estimated that three months will be required for the construction and testing of such a model and that the cost will be approximately three thousand dollars, one thousand dollars of which will be for the motors. No suitable location appears to exist in any of our present buildings, and it may be necessary to build it outside and cover it with a roof.' George Lewis responded immediately (June 27) granting the authority to proceed. He urged Langley to expedite construction and to employ extra carpenters if necessary. Funds for the model came from the FST project. In a 1979
AN ORIGINAL ECONOMETRIC MODEL OF FDI IN ROMANIA
Directory of Open Access Journals (Sweden)
Gheorghe SĂVOIU
2012-04-01
Full Text Available The central theme of this paper is, as the title itself shows, the econometric modelling of Foreign Direct Investments (FDI, based on the concept Euromoney’ s country risk rating. This article contains three sections, the first part or the introduction is an approach of investment risk and, in particular, introduces a new element in modelling investment, namely country risk rating. Thus, a bridge is created towards the second section, which essentially deals with the econometric modelling of foreign direct investment (FDI in Romania, after 1996, based on Euromoney’s data (ECR. The originality of this paper is underlined by the presence of a final model which includes, as an exogenous variable, country risk rating in assessing the FDI share of GDP as an endogenous variable. A final remark comments, from an economic perspective, the results of the econometric modelling.
Numerical modelling of nonlinear full-wave acoustic propagation
Energy Technology Data Exchange (ETDEWEB)
Velasco-Segura, Roberto, E-mail: roberto.velasco@ccadet.unam.mx; Rendón, Pablo L., E-mail: pablo.rendon@ccadet.unam.mx [Grupo de Acústica y Vibraciones, Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, Ciudad Universitaria, Apartado Postal 70-186, C.P. 04510, México D.F., México (Mexico)
2015-10-28
The various model equations of nonlinear acoustics are arrived at by making assumptions which permit the observation of the interaction with propagation of either single or joint effects. We present here a form of the conservation equations of fluid dynamics which are deduced using slightly less restrictive hypothesis than those necessary to obtain the well known Westervelt equation. This formulation accounts for full wave diffraction, nonlinearity, and thermoviscous dissipative effects. A two-dimensional, finite-volume method using Roe’s linearisation has been implemented to obtain numerically the solution of the proposed equations. This code, which has been written for parallel execution on a GPU, can be used to describe moderate nonlinear phenomena, at low Mach numbers, in domains as large as 100 wave lengths. Applications range from models of diagnostic and therapeutic HIFU, to parametric acoustic arrays and nonlinear propagation in acoustic waveguides. Examples related to these applications are shown and discussed.
Full Eulerian lattice Boltzmann model for conjugate heat transfer.
Hu, Yang; Li, Decai; Shu, Shi; Niu, Xiaodong
2015-12-01
In this paper a full Eulerian lattice Boltzmann model is proposed for conjugate heat transfer. A unified governing equation with a source term for the temperature field is derived. By introducing the source term, we prove that the continuity of temperature and its normal flux at the interface is satisfied automatically. The curved interface is assumed to be zigzag lines. All physical quantities are recorded and updated on a Cartesian grid. As a result, any complicated treatment near the interface is avoided, which makes the proposed model suitable to simulate the conjugate heat transfer with complex interfaces efficiently. The present conjugate interface treatment is validated by several steady and unsteady numerical tests, including pure heat conduction, forced convection, and natural convection problems. Both flat and curved interfaces are also involved. The obtained results show good agreement with the analytical and/or finite volume results.
The full Ward-Takahashi Identity for colored tensor models
Pérez-Sánchez, Carlos I
2016-01-01
We derive the full $\\mathrm{U}(\\infty)$-Ward-Takahashi Identities for random colored tensor models. The strategy is to expand the free energy in boundary graphs that determine the combinatorics of the sources. This contributes to the organization of the correlation functions of colored tensor models and is carried out for arbitrary interactions of any rank, $D$, with subsequent focus on the $\\varphi^4$-theories. The result is that the boundary sector of quartic melonic interactions suffices to generate all $D$-colored graphs. For the rank-$3$ $\\varphi^4$-theory we derive the exact integral-like equation for the 2-point function. Our results hold for some Group Field Theories as well. Altogether, our non-perturbative approach trades graph theory for analytical methods.
Full-field feature profile models in process control
Zavecz, Terrence E.
2005-05-01
Most process window analysis applications are capable of deriving the functional focus-dose workspace available to any set of device specifications. Previous work in this area has concentrated on calculating the superpositioned optimum operating points of various combinations of feature orientations or feature types. These studies invariably result in an average performance calculation that is biased by the impact of the substrate, reticle and exposure tool contributed perturbations. Many SEM's and optical metrology tools now provide full-feature profile information for multiple points in the exposure field. The inclusion of field spatial information into the process window analysis results in a calculation of greater accuracy and process understanding because now the capabilities of each exposure tool can be individually modeled and optimized. Such an analysis provides the added benefit that after the exposure tool is characterized, it's process perturbations can be removed from the analysis to provide greater understanding of the true process performance. Process window variables are shown to vary significantly across the exposure field of the scanner. Evaluating the depth-of-focus and optimum focus-dose at each point in the exposure field yields additional information on the imaging response of the reticle and scan-linearity of the exposure tool's reticle stage. The optimal focus response of the reticle is then removed from a full wafer exposure and the results are modeled to obtain a true process response and performance.
Model Wind Turbines Tested at Full-Scale Similarity
Miller, M. A.; Kiefer, J.; Westergaard, C.; Hultmark, M.
2016-09-01
The enormous length scales associated with modern wind turbines complicate any efforts to predict their mechanical loads and performance. Both experiments and numerical simulations are constrained by the large Reynolds numbers governing the full- scale aerodynamics. The limited fundamental understanding of Reynolds number effects in combination with the lack of empirical data affects our ability to predict, model, and design improved turbines and wind farms. A new experimental approach is presented, which utilizes a highly pressurized wind tunnel (up to 220 bar). It allows exact matching of the Reynolds numbers (no matter how it is defined), tip speed ratios, and Mach numbers on a geometrically similar, small-scale model. The design of a measurement and instrumentation stack to control the turbine and measure the loads in the pressurized environment is discussed. Results are then presented in the form of power coefficients as a function of Reynolds number and Tip Speed Ratio. Due to gearbox power loss, a preliminary study has also been completed to find the gearbox efficiency and the resulting correction has been applied to the data set.
The early origins of the logit model
Cramer, J.S.
2004-01-01
This paper describes the origins of the logistic function and its history up to its adoption in bio-assay and the beginning of its wider acceptance in statistics, ca. 1950. The function was probably first invented in 1838 to describe population growth by the Belgian mathematician Verhulst, who gave
Transistor roadmap projection using predictive full-band atomistic modeling
Energy Technology Data Exchange (ETDEWEB)
Salmani-Jelodar, M., E-mail: m.salmani@gmail.com; Klimeck, G. [Network for Computational Nanotechnology and School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Kim, S. [Intel Corporation, 2501 Northwest 229th Avenue, Hillsboro, Oregon 97124 (United States); Ng, K. [Semiconductor Research Corporation (SRC), 1101 Slater Rd, Durham, North Carolina 27703 (United States)
2014-08-25
In this letter, a full band atomistic quantum transport tool is used to predict the performance of double gate metal-oxide-semiconductor field-effect transistors (MOSFETs) over the next 15 years for International Technology Roadmap for Semiconductors (ITRS). As MOSFET channel lengths scale below 20 nm, the number of atoms in the device cross-sections becomes finite. At this scale, quantum mechanical effects play an important role in determining the device characteristics. These quantum effects can be captured with the quantum transport tool. Critical results show the ON-current degradation as a result of geometry scaling, which is in contrast to previous ITRS compact model calculations. Geometric scaling has significant effects on the ON-current by increasing source-to-drain (S/D) tunneling and altering the electronic band structure. By shortening the device gate length from 20 nm to 5.1 nm, the ratio of S/D tunneling current to the overall subthreshold OFF-current increases from 18% to 98%. Despite this ON-current degradation by scaling, the intrinsic device speed is projected to increase at a rate of at least 8% per year as a result of the reduction of the quantum capacitance.
Chance of Necessity: Modeling Origins of Life
Pohorille, Andrew
2006-01-01
The fundamental nature of processes that led to the emergence of life has been a subject of long-standing debate. One view holds that the origin of life is an event governed by chance, and the result of so many random events is unpredictable. This view was eloquently expressed by Jacques Monod in his book Chance or Necessity. In an alternative view, the origin of life is considered a deterministic event. Its details need not be deterministic in every respect, but the overall behavior is predictable. A corollary to the deterministic view is that the emergence of life must have been determined primarily by universal chemistry and biochemistry rather than by subtle details of environmental conditions. In my lecture I will explore two different paradigms for the emergence of life and discuss their implications for predictability and universality of life-forming processes. The dominant approach is that the origin of life was guided by information stored in nucleic acids (the RNA World hypothesis). In this view, selection of improved combinations of nucleic acids obtained through random mutations drove evolution of biological systems from their conception. An alternative hypothesis states that the formation of protocellular metabolism was driven by non-genomic processes. Even though these processes were highly stochastic the outcome was largely deterministic, strongly constrained by laws of chemistry. I will argue that self-replication of macromolecules was not required at the early stages of evolution; the reproduction of cellular functions alone was sufficient for self-maintenance of protocells. In fact, the precise transfer of information between successive generations of the earliest protocells was unnecessary and could have impeded the discovery of cellular metabolism. I will also show that such concepts as speciation and fitness to the environment, developed in the context of genomic evolution also hold in the absence of a genome.
Non-lane-based full velocity difference car following model
Jin, Sheng; Wang, Dianhai; Tao, Pengfei; Li, Pingfan
2010-11-01
In order to describe car following behavior in real world, this paper presents a non-lane-based car following model by incorporating the effects of the lane width in traffic. The stability condition of the model is obtained by using the linear stability theory. And numerical simulation is carried out to validate the analytic results. The property of the model is investigated, and it is found that the proposed model can describe the phase transition of traffic flow and estimate the evolution of traffic congestion. The results implied that incorporating the lane width effects in car following model not only stabilize traffic flow and suppress the traffic jam, but also lower critical headway and increase capacity. Thus, the lateral separation effects greatly enhance the realism of car following models.
Full Hydrodynamic Model of Nonlinear Electromagnetic Response in Metallic Metamaterials
Fang, Ming; Sha, Wei E I; Xiong, Xiaoyan Y Z; Wu, Xianliang
2016-01-01
Applications of metallic metamaterials have generated significant interest in recent years. Electromagnetic behavior of metamaterials in the optical range is usually characterized by a local-linear response. In this article, we develop a finite-difference time-domain (FDTD) solution of the hydrodynamic model that describes a free electron gas in metals. Extending beyond the local-linear response, the hydrodynamic model enables numerical investigation of nonlocal and nonlinear interactions between electromagnetic waves and metallic metamaterials. By explicitly imposing the current continuity constraint, the proposed model is solved in a self-consistent manner. Charge, energy and angular momentum conservation laws of high-order harmonic generation have been demonstrated for the first time by the Maxwell-hydrodynamic FDTD model. The model yields nonlinear optical responses for complex metallic metamaterials irradiated by a variety of waveforms. Consequently, the multiphysics model opens up unique opportunities f...
A Strongly Grounded Stable Model Semantics for Full Propositional Language
2012-01-01
Answer set programming is one of the most praised frameworks for declarative programming in general and non-monotonic reasoning in particular. There has been many efforts to extend stable model semantics so that answer set programs can use a more extensive syntax. To such endeavor, the community of non-monotonic reasoning has introduced extensions such as equilibrium models and FLP semantics. However, both of these extensions suffer from two problems: intended models according to such extensi...
Fares, Ehab; Duda, Benjamin; Khorrami, Mehdi R.
2016-01-01
Unsteady flow computations are presented for a Gulfstream aircraft model in landing configuration, i.e., flap deflected 39deg and main landing gear deployed. The simulations employ the lattice Boltzmann solver PowerFLOW(Trademark) to simultaneously capture the flow physics and acoustics in the near field. Sound propagation to the far field is obtained using a Ffowcs Williams and Hawkings acoustic analogy approach. Two geometry representations of the same aircraft are analyzed: an 18% scale, high-fidelity, semi-span model at wind tunnel Reynolds number and a full-scale, full-span model at half-flight Reynolds number. Previously published and newly generated model-scale results are presented; all full-scale data are disclosed here for the first time. Reynolds number and geometrical fidelity effects are carefully examined to discern aerodynamic and aeroacoustic trends with a special focus on the scaling of surface pressure fluctuations and farfield noise. An additional study of the effects of geometrical detail on farfield noise is also documented. The present investigation reveals that, overall, the model-scale and full-scale aeroacoustic results compare rather well. Nevertheless, the study also highlights that finer geometrical details that are typically not captured at model scales can have a non-negligible contribution to the farfield noise signature.
Full spatially resolved laser modeling and design using GLOSS
Hudock, Jared; Decker, Mark; Koroshetz, John
2016-05-01
L-3 ALST has developed a Generalized Laser and Optics Simulation Suite (GLOSS) to quickly and reliably design high performance laser transmitters. GLOSS uses state of the art wave propagation based algorithms to rigorously simulate the dynamics of laser oscillation. Laser pulse energy, pulse width, beam size, beam shape, and divergence are among the many key performances parameters GLOSS models have the capability to predict. The GLOSS modeling methodology will be discussed and examples of its powerful capability will be demonstrated. Model predictions within 10-15% of actual laser performance data from a sample of experimental lasers will also be shown.
A dynamical model for the full stretching curve of DNA
Fiasconaro, Alessandro
2012-01-01
We present a phenomenological dynamical model able to describe the stretching features of a length \\textit{vs} applied force DNA curve. As concerning the chain, the model grounds on the discrete worm-like chain model with the elastic modifications, which properly describes the elongation features at low and intermediate forces. At high forces the dynamics, developed under a double well potential with a cubic term, accounts for the narrow transition present in the DNA elongation (overstretching). An good agreement between simulation and experiment is obtained.
Tessera terrain: Characteristics and models of origin
Bindschadler, D. L.; Head, James W.
1989-01-01
Tessera terrain consists of complexly deformed regions characterized by sets of ridges and valleys that intersect at angles ranging from orthogonal to oblique, and were first viewed in Venera 15/16 SAR data. Tesserae cover more area (approx. 15 percent of the area north of 30 deg N) than any of the other tectonic units mapped from the Venera data and are strongly concentrated in the region between longitudes 0 deg E and 150 deg E. Tessera terrain is concentrated between a proposed center of crustal extension and divergence in Aphrodite and a region of intense deformation, crustal convergence, and orogenesis in western Ishtar Terra. Thus, the tectonic processes responsible for tesserae are an important part of Venus tectonics. As part of an effort to understand the formation and evolution of this unusual terrain type, the basic characteristics of the tesserae were compared to the predictions made by a number of tectonic models. The basic characteristics of tessera terrain are described and the models and some of their basic predictions are briefly discussed.
Vortex ring state by full-field actuator disc model
Energy Technology Data Exchange (ETDEWEB)
Soerensen, J.N.; Shen, W.Z.; Munduate, X. [DTU, Dept. of Energy Engineering, Lyngby (Denmark)
1997-08-01
One-dimensional momentum theory provides a simple analytical tool for analysing the gross flow behavior of lifting propellers and rotors. Combined with a blade-element strip-theory approach, it has for many years been the most popular model for load and performance predictions of wind turbines. The model works well at moderate and high wind velocities, but is not reliable at small wind velocities, where the expansion of the wake is large and the flow field behind the rotor dominated by turbulent mixing. This is normally referred to as the turbulent wake state or the vortex ring state. In the vortex ring state, momentum theory predicts a decrease of thrust whereas the opposite is found from experiments. The reason for the disagreement is that recirculation takes place behind the rotor with the consequence that the stream tubes past the rotor becomes effectively chocked. This represents a condition at which streamlines no longer carry fluid elements from far upstream to far downstream, hence one-dimensional momentum theory is invalid and empirical corrections have to be introduced. More sophisticated analytical or semi-analytical rotor models have been used to describe stationary flow fields for heavily loaded propellers. In recent years generalized actuator disc models have been developed, but up to now no detailed computations of the turbulent wake state or the vortex ring state have been performed. In the present work the phenomenon is simulated by direct simulation of the Navier-Stokes equations, where the influence of the rotor on the flow field is modelled simply by replacing the blades by an actuator disc with a constant normal load. (EG) 13 refs.
Calibration of Airframe and Occupant Models for Two Full-Scale Rotorcraft Crash Tests
Annett, Martin S.; Horta, Lucas G.; Polanco, Michael A.
2012-01-01
Two full-scale crash tests of an MD-500 helicopter were conducted in 2009 and 2010 at NASA Langley's Landing and Impact Research Facility in support of NASA s Subsonic Rotary Wing Crashworthiness Project. The first crash test was conducted to evaluate the performance of an externally mounted composite deployable energy absorber under combined impact conditions. In the second crash test, the energy absorber was removed to establish baseline loads that are regarded as severe but survivable. Accelerations and kinematic data collected from the crash tests were compared to a system integrated finite element model of the test article. Results from 19 accelerometers placed throughout the airframe were compared to finite element model responses. The model developed for the purposes of predicting acceleration responses from the first crash test was inadequate when evaluating more severe conditions seen in the second crash test. A newly developed model calibration approach that includes uncertainty estimation, parameter sensitivity, impact shape orthogonality, and numerical optimization was used to calibrate model results for the second full-scale crash test. This combination of heuristic and quantitative methods was used to identify modeling deficiencies, evaluate parameter importance, and propose required model changes. It is shown that the multi-dimensional calibration techniques presented here are particularly effective in identifying model adequacy. Acceleration results for the calibrated model were compared to test results and the original model results. There was a noticeable improvement in the pilot and co-pilot region, a slight improvement in the occupant model response, and an over-stiffening effect in the passenger region. This approach should be adopted early on, in combination with the building-block approaches that are customarily used, for model development and test planning guidance. Complete crash simulations with validated finite element models can be used
Mathematical Modeling of the Origins of Life
Pohorille, Andrew
2006-01-01
The emergence of early metabolism - a network of catalyzed chemical reactions that supported self-maintenance, growth, reproduction and evolution of the ancestors of contemporary cells (protocells) was a critical, but still very poorly understood step on the path from inanimate to animate matter. Here, it is proposed and tested through mathematical modeling of biochemically plausible systems that the emergence of metabolism and its initial evolution towards higher complexity preceded the emergence of a genome. Even though the formation of protocellular metabolism was driven by non-genomic, highly stochastic processes the outcome was largely deterministic, strongly constrained by laws of chemistry. It is shown that such concepts as speciation and fitness to the environment, developed in the context of genomic evolution, also held in the absence of a genome.
Domain-specific modeling enabling full code generation
Kelly, Steven
2007-01-01
Domain-Specific Modeling (DSM) is the latest approach tosoftware development, promising to greatly increase the speed andease of software creation. Early adopters of DSM have been enjoyingproductivity increases of 500–1000% in production for over adecade. This book introduces DSM and offers examples from variousfields to illustrate to experienced developers how DSM can improvesoftware development in their teams. Two authorities in the field explain what DSM is, why it works,and how to successfully create and use a DSM solution to improveproductivity and quality. Divided into four parts, the book covers:background and motivation; fundamentals; in-depth examples; andcreating DSM solutions. There is an emphasis throughout the book onpractical guidelines for implementing DSM, including how toidentify the nece sary language constructs, how to generate fullcode from models, and how to provide tool support for a new DSMlanguage. The example cases described in the book are available thebook's Website, www.dsmbook....
Modelling the full trip costs of urban intermodal passenger transport
Yeh, Chao-Fu; Papon, Francis
2011-01-01
To face the competition of private motorized vehicles, intermodal transport becomes a successful condition to encourage public transport and non-motorized modes and to reasonably control the continual growth of individual motorized vehicles in the city area. Therefore, the objective of this research intends to develop a comparable calculating model combining the private, public and external costs of passenger urban transport networks. Private costs consist in the operational-private costs bor...
Pacemaker dynamics in the full Morris-Lecar model
González-Miranda, J. M.
2014-09-01
This article reports the finding of pacemaker dynamics in certain region of the parameter space of the three-dimensional version of the Morris-Lecar model for the voltage oscillations of a muscle cell. This means that the cell membrane potential displays sustained oscillations in the absence of an external electrical stimulation. The development of this dynamic behavior is shown to be tied to the strength of the leak current contained in the model. The approach followed is mostly based on the use of linear stability analysis and numerical continuation techniques. In this way it is shown that the oscillatory dynamics is associated to the existence of two Hopf bifurcations, one subcritical and other supercritical. Moreover, it is explained that in the region of parameter values most commonly studied for this model such pacemaker dynamics is not displayed because of the development of two fold bifurcations, with the increase of the strength of the leak current, whose interaction with the Hopf bifurcations destroys the oscillatory dynamics.
Full Phase Diagram of the Massive Gross-Neveu Model
Schnetz, O; Urlichs, K; Schnetz, Oliver; Thies, Michael; Urlichs, Konrad
2006-01-01
The massive Gross-Neveu model is solved in the large N limit at finite temperature and chemical potential. The scalar potential is given in terms of Jacobi elliptic functions. It contains three parameters which are determined by transcendental equations. Self-consistency of the scalar potential is proved. The phase diagram for non-zero bare quark mass is found to contain a kink-antikink crystal phase as well as a massive fermion gas phase featuring a cross-over from light to heavy effective fermion mass. For zero bare quark mass we recover the three known phases kink-antikink crystal, massless fermion gas, and massive fermion gas. All phase transitions are shown to be of second order. Equations for the phase boundaries are given and solved numerically. Implications on condensed matter physics are indicated where our results generalize the bipolaron lattice in non-degenerate conducting polymers to finite temperature.
Online-Offline, 1999
1999-01-01
Provides an annotated list of resources dealing with the theme of origins of life, the universe, and traditions. Includes Web sites, videos, books, audio materials, and magazines with appropriate grade levels and/or subject disciplines indicated; professional resources; and learning activities. (LRW)
An integrated factor analysis model for product eco-design based on full life cycle assessment
Directory of Open Access Journals (Sweden)
Zhi fang Zhou
2016-02-01
Full Text Available Purpose: Among the methods of comprehensive analysis for a product or an enterprise, there exist defects and deficiencies in traditional standard cost analyses and life cycle assessment methods. For example, some methods only emphasize one dimension (such as economic or environmental factors while neglecting other relevant dimensions. This paper builds a factor analysis model of resource value flow, based on full life cycle assessment and eco-design theory, in order to expose the relevant internal logic between these two factors. Design/methodology/approach: The model considers the efficient multiplication of resources, economic efficiency, and environmental efficiency as its core objectives. The model studies the status of resource value flow during the entire life cycle of a product, and gives an in-depth analysis on the mutual logical relationship of product performance, value, resource consumption, and environmental load to reveal the symptoms and potentials in different dimensions. Originality/value: This provides comprehensive, accurate and timely decision-making information for enterprise managers regarding product eco-design, as well as production and management activities. To conclude, it verifies the availability of this evaluation and analysis model using a Chinese SUV manufacturer as an example.
Theory, modelling and simulation in origins of life studies.
Coveney, Peter V; Swadling, Jacob B; Wattis, Jonathan A D; Greenwell, H Christopher
2012-08-21
Origins of life studies represent an exciting and highly multidisciplinary research field. In this review we focus on the contributions made by theory, modelling and simulation to addressing fundamental issues in the domain and the advances these approaches have helped to make in the field. Theoretical approaches will continue to make a major impact at the "systems chemistry" level based on the analysis of the remarkable properties of nonlinear catalytic chemical reaction networks, which arise due to the auto-catalytic and cross-catalytic nature of so many of the putative processes associated with self-replication and self-reproduction. In this way, we describe inter alia nonlinear kinetic models of RNA replication within a primordial Darwinian soup, the origins of homochirality and homochiral polymerization. We then discuss state-of-the-art computationally-based molecular modelling techniques that are currently being deployed to investigate various scenarios relevant to the origins of life.
Lifescience Database Archive (English)
Full Text Available L, Baron MK, Marcotte EM, Eisenberg D., Nucleic Acids Res. 2000 Jan 1;28(1):289-91. *5 KEGG: kyoto encycl...opedia of genes and genomes. , Kanehisa M, Goto S., Nucleic Acids Res. 2000 Jan 1;2
Directory of Open Access Journals (Sweden)
Fabio Silva
Full Text Available We have compiled an extensive database of archaeological evidence for rice across Asia, including 400 sites from mainland East Asia, Southeast Asia and South Asia. This dataset is used to compare several models for the geographical origins of rice cultivation and infer the most likely region(s for its origins and subsequent outward diffusion. The approach is based on regression modelling wherein goodness of fit is obtained from power law quantile regressions of the archaeologically inferred age versus a least-cost distance from the putative origin(s. The Fast Marching method is used to estimate the least-cost distances based on simple geographical features. The origin region that best fits the archaeobotanical data is also compared to other hypothetical geographical origins derived from the literature, including from genetics, archaeology and historical linguistics. The model that best fits all available archaeological evidence is a dual origin model with two centres for the cultivation and dispersal of rice focused on the Middle Yangtze and the Lower Yangtze valleys.
Robinson, Orin J.; McGowan, Conor; Devers, Patrick K.
2017-01-01
Density dependence regulates populations of many species across all taxonomic groups. Understanding density dependence is vital for predicting the effects of climate, habitat loss and/or management actions on wild populations. Migratory species likely experience seasonal changes in the relative influence of density dependence on population processes such as survival and recruitment throughout the annual cycle. These effects must be accounted for when characterizing migratory populations via population models.To evaluate effects of density on seasonal survival and recruitment of a migratory species, we used an existing full annual cycle model framework for American black ducks Anas rubripes, and tested different density effects (including no effects) on survival and recruitment. We then used a Bayesian model weight updating routine to determine which population model best fit observed breeding population survey data between 1990 and 2014.The models that best fit the survey data suggested that survival and recruitment were affected by density dependence and that density effects were stronger on adult survival during the breeding season than during the non-breeding season.Analysis also suggests that regulation of survival and recruitment by density varied over time. Our results showed that different characterizations of density regulations changed every 8–12 years (three times in the 25-year period) for our population.Synthesis and applications. Using a full annual cycle, modelling framework and model weighting routine will be helpful in evaluating density dependence for migratory species in both the short and long term. We used this method to disentangle the seasonal effects of density on the continental American black duck population which will allow managers to better evaluate the effects of habitat loss and potential habitat management actions throughout the annual cycle. The method here may allow researchers to hone in on the proper form and/or strength of
Investigating the Common Origins of Stars Using Dynamical Modeling
Gutierrez, Elizabeth; Ramirez, Ivan
2017-01-01
Dynamical modeling of stars’ orbits past in time is a robust method in finding stars of common birth origins. Here we present a dynamical study using the Python package galpy to investigate: 1) solar twins and the possibility of them having common birth origins with our Sun or each other and 2) the planet-hosting star iota Horologii proposed to have formed in the Hyades cluster. Solar twins are stars with spectra nearly identical to the Sun. Using a large sample of solar twins, we applied a standard Galactic model to investigate whether these stars have common origins with the Sun or each other at their respective ages, finding only very weak associations. In our investigation of the planet-hosting star iota Horologii, we challenge previous claims in favor of iota Horologii being an evaporated Hyades star. In our dynamical model, we compare the location of iota Horologii back in time to the average location of a representative sample of true Hyades stars, finding this star to have never converged with the cluster. Our results reveal the fundamental importance of dynamical modeling in the identification of stellar siblings.
Directory of Open Access Journals (Sweden)
Daniel Malouli
2014-09-01
Full Text Available Multiple novel simian adenoviruses have been isolated over the past years and their potential to cross the species barrier and infect the human population is an ever present threat. Here we describe the isolation and full genome sequencing of a novel simian adenovirus (SAdV isolated from the urine of two independent, never co-housed, late stage simian immunodeficiency virus (SIV-infected rhesus macaques. The viral genome sequences revealed a novel type with a unique genome length, GC content, E3 region and DNA polymerase amino acid sequence that is sufficiently distinct from all currently known human- or simian adenovirus species to warrant classifying these isolates as a novel species of simian adenovirus. This new species, termed Simian mastadenovirus D (SAdV-D, displays the standard genome organization for the genus Mastadenovirus containing only one copy of the fiber gene which sets it apart from the old world monkey adenovirus species HAdV-G, SAdV-B and SAdV-C.
Coupled Models and Parallel Simulations for Three-Dimensional Full-Stokes Ice Sheet Modeling
Energy Technology Data Exchange (ETDEWEB)
Zhang, Huai; Ju, Lili
2011-01-01
A three-dimensional full-Stokes computational model is considered for determining the dynamics, temperature, and thickness of ice sheets. The governing thermomechanical equations consist of the three-dimensional full-Stokes system with nonlinear rheology for the momentum, an advective-diffusion energy equation for temperature evolution, and a mass conservation equation for icethickness changes. Here, we discuss the variable resolution meshes, the finite element discretizations, and the parallel algorithms employed by the model components. The solvers are integrated through a well-designed coupler for the exchange of parametric data between components. The discretization utilizes high-quality, variable-resolution centroidal Voronoi Delaunay triangulation meshing and existing parallel solvers. We demonstrate the gridding technology, discretization schemes, and the efficiency and scalability of the parallel solvers through computational experiments using both simplified geometries arising from benchmark test problems and a realistic Greenland ice sheet geometry.
Full 3-D numerical modeling of borehole electric image logging and the evaluation model of fracture
Institute of Scientific and Technical Information of China (English)
2008-01-01
A full 3-D finite element method numerical modeling program is written based on the principle and technical specification of borehole electric image well logging tool. The response of well logging is computed in the formation media model with a single fracture. The effect of changing fracture aperture and resistivity ratio to the logging response is discussed. The identification ability for two parallel fractures is also present. A quantitative evaluation formula of fracture aperture from borehole electric image logging data is set up. A case study of the model well is done to verify the accuracy of the for-mula. The result indicates that the formula is more accurate than the foreign one.
Modelling debris transport within glaciers by advection in a full-Stokes ice flow model
Wirbel, Anna; Jarosch, Alexander H.; Nicholson, Lindsey
2017-04-01
As mountain glaciers recede worldwide, an increasing proportion of the remaining glacierized area is expected to become debris covered. The spatio-temporal development of a surface debris cover has profound effects on the glacier behaviour and meltwater generation, yet little is known about how glacier dynamics influence the spatial distribution of an emerging debris cover. Motivated by this lack of understanding, we present a coupled model to simulate advection and resulting deformation of debris features within glaciers. The finite element model developed in python consists of an advection scheme coupled to a full-Stokes ice flow model, using FEniCS as the numerical framework. We show results from numerical tests that demonstrate its suitability to model advection-dominated transport of concentration in a divergence-free velocity field. The capabilities of the coupled model are demonstrated by simulating transport of debris features of different initial size, shape and location through modelled velocity fields of representative mountain glaciers. The results indicate that deformation of initial debris inputs, as a consequence of being transported through the glacier, plays an important role in determining the location and rate of debris emergence at the glacier surface. The presented work lays the foundation for comprehensive simulations of realistic patterns of debris cover, their spatial and temporal variability and the timescales over which debris covers can form.
A Compound model for the origin of Earth's water
Torres, K de Souza; Izidoro, A; Haghighipour, N
2013-01-01
One of the most important subjects of debate in the formation of the solar system is the origin of Earth's water. Comets have long been considered as the most likely source of the delivery of water to Earth. However, elemental and isotopic arguments suggest a very small contribution from these objects. Other sources have also been proposed, among which, local adsorption of water vapor onto dust grains in the primordial nebula and delivery through planetesimals and planetary embryos have become more prominent. However, no sole source of water provides a satisfactory explanation for Earth's water as a whole. In view of that, using numerical simulations, we have developed a compound model incorporating both the principal endogenous and exogenous theories, and investigating their implications for terrestrial planet formation and water-delivery. Comets are also considered in the final analysis, as it is likely that at least some of Earth's water has cometary origin. We analyze our results comparing two different w...
A Dirichlet Process Mixture Based Name Origin Clustering and Alignment Model for Transliteration
Directory of Open Access Journals (Sweden)
Chunyue Zhang
2015-01-01
Full Text Available In machine transliteration, it is common that the transliterated names in the target language come from multiple language origins. A conventional maximum likelihood based single model can not deal with this issue very well and often suffers from overfitting. In this paper, we exploit a coupled Dirichlet process mixture model (cDPMM to address overfitting and names multiorigin cluster issues simultaneously in the transliteration sequence alignment step over the name pairs. After the alignment step, the cDPMM clusters name pairs into many groups according to their origin information automatically. In the decoding step, in order to use the learned origin information sufficiently, we use a cluster combination method (CCM to build clustering-specific transliteration models by combining small clusters into large ones based on the perplexities of name language and transliteration model, which makes sure each origin cluster has enough data for training a transliteration model. On the three different Western-Chinese multiorigin names corpora, the cDPMM outperforms two state-of-the-art baseline models in terms of both the top-1 accuracy and mean F-score, and furthermore the CCM significantly improves the cDPMM.
Directory of Open Access Journals (Sweden)
Sabrina Clavijo-Baque
Full Text Available The origin of endothermy is a puzzling phenomenon in the evolution of vertebrates. To address this issue several explicative models have been proposed. The main models proposed for the origin of endothermy are the aerobic capacity, the thermoregulatory and the parental care models. Our main proposal is that to compare the alternative models, a critical aspect is to determine how strongly natural selection was influenced by body temperature, and basal and maximum metabolic rates during the evolution of endothermy. We evaluate these relationships in the context of three main hypotheses aimed at explaining the evolution of endothermy, namely the parental care hypothesis and two hypotheses related to the thermoregulatory model (thermogenic capacity and higher body temperature models. We used data on basal and maximum metabolic rates and body temperature from 17 rodent populations, and used intrinsic population growth rate (R(max as a global proxy of fitness. We found greater support for the thermogenic capacity model of the thermoregulatory model. In other words, greater thermogenic capacity is associated with increased fitness in rodent populations. To our knowledge, this is the first test of the fitness consequences of the thermoregulatory and parental care models for the origin of endothermy.
Modelling and Simulation of Variable Speed Thruster Drives with Full-Scale Verification
Directory of Open Access Journals (Sweden)
Jan F. Hansen
2001-10-01
Full Text Available In this paper considerations about modelling and simulation of variable speed thruster drives are made with comparison to full scale measurements from Varg FPSO. For special purpose vessels with electric propulsion operating in DP (Dynamic Positioning mode the thruster drives are essential for the vessel operation. Different model strategies of thruster drives are discussed. An advanced thruster drive model with a dynamic motor model and field vector control principle is shown. Simulations are performed with both the advanced model and a simplified model. These are compared with full-scale measurements from Varg FPSO. The simulation results correspond well with the measurements, for both the simplified model and the advanced model.
Benchmark experiments for higher-order and full-Stokes ice sheet models (ISMIP–HOM
Directory of Open Access Journals (Sweden)
F. Pattyn
2008-08-01
Full Text Available We present the results of the first ice sheet model intercomparison project for higher-order and full-Stokes ice sheet models. These models are compared and verified in a series of six experiments of which one has an analytical solution obtained from a perturbation analysis. The experiments are applied to both 2-D and 3-D geometries; five experiments are steady-state diagnostic, and one has a time-dependent prognostic solution. All participating models give results that are in close agreement. A clear distinction can be made between higher-order models and those that solve the full system of equations. The full-Stokes models show a much smaller spread, hence are in better agreement with one another and with the analytical solution.
An adaptive radiation model for the origin of new genefunctions
Energy Technology Data Exchange (ETDEWEB)
Francino, M. Pilar
2004-10-18
The evolution of new gene functions is one of the keys to evolutionary innovation. Most novel functions result from gene duplication followed by divergence. However, the models hitherto proposed to account for this process are not fully satisfactory. The classic model of neofunctionalization holds that the two paralogous gene copies resulting from a duplication are functionally redundant, such that one of them can evolve under no functional constraints and occasionally acquire a new function. This model lacks a convincing mechanism for the new gene copies to increase in frequency in the population and survive the mutational load expected to accumulate under neutrality, before the acquisition of the rare beneficial mutations that would confer new functionality. The subfunctionalization model has been proposed as an alternative way to generate genes with altered functions. This model also assumes that new paralogous gene copies are functionally redundant and therefore neutral, but it predicts that relaxed selection will affect both gene copies such that some of the capabilities of the parent gene will disappear in one of the copies and be retained in the other. Thus, the functions originally present in a single gene will be partitioned between the two descendant copies. However, although this model can explain increases in gene number, it does not really address the main evolutionary question, which is the development of new biochemical capabilities. Recently, a new concept has been introduced into the gene evolution literature which is most likely to help solve this dilemma. The key point is to allow for a period of natural selection for the duplication per se, before new function evolves, rather than considering gene duplication to be neutral as in the previous models. Here, I suggest a new model that draws on the advantage of postulating selection for gene duplication, and proposes that bursts of adaptive gene amplification in response to specific selection
Gao, Zhibin; Li, Nianbei; Li, Baowen
2016-02-01
The ding-a-ling model is a kind of half lattice and half hard-point-gas (HPG) model. The original ding-a-ling model proposed by Casati et al. does not conserve total momentum and has been found to exhibit normal heat conduction behavior. Recently, a modified ding-a-ling model which conserves total momentum has been studied and normal heat conduction has also been claimed. In this work, we propose a full-lattice ding-a-ling model without hard point collisions where total momentum is also conserved. We investigate the heat conduction and energy diffusion of this full-lattice ding-a-ling model with three different nonlinear inter-particle potential forms. For symmetrical potential lattices, the thermal conductivities diverges with lattice length and their energy diffusions are superdiffusive signaturing anomalous heat conduction. For asymmetrical potential lattices, although the thermal conductivity seems to converge as the length increases, the energy diffusion is definitely deviating from normal diffusion behavior indicating anomalous heat conduction as well. No normal heat conduction behavior can be found for the full-lattice ding-a-ling model.
A model-building approach to the origin of flavor
Energy Technology Data Exchange (ETDEWEB)
Schumacher, Erik
2017-01-24
In this thesis we link the recent anomalies reported in B meson and h→μτ decays to the smallness of neutrino masses and aspects of the flavor puzzle, including the hierarchy of the Yukawa couplings and the disparate fermion mixings. By formulating various new models we attempt to shed light on the potential common origin of the distinct measurements in the flavor sector. To this end, discrete symmetries are utilized in this work as the governing principle behind all fermion interactions. The first two models based on the S{sub 3} and the A{sub 4} symmetry, respectively, aim to unify the diverse fermion masses and mixings. Special features separate the frameworks from the flavor models in the literature that often lack testable predictions. While the first model provides interesting flavor-violating signatures in top quark decays, the second one ties the flavor to the grand unification scale in a novel way. In the three following models we focus on the anomalies that hint at lepton flavor and universality violation. We propose that the large flavor violation observed in h→μτ decays is dictated by the scalar mixing of an enlarged S{sub 4}-symmetric Higgs sector. By constructing two leptoquark models we show for the first time that leptoquark couplings shaped by a Froggatt-Nielsen mechanism can accommodate the B meson anomalies and simultaneously generate naturally-small neutrino masses. Emphasizing the importance of testability, we demonstrate how these models can be probed by future diphoton resonances, using the recent 750 GeV excess as an example scenario.
Modeling Coevolution between Language and Memory Capacity during Language Origin.
Gong, Tao; Shuai, Lan
2015-01-01
Memory is essential to many cognitive tasks including language. Apart from empirical studies of memory effects on language acquisition and use, there lack sufficient evolutionary explorations on whether a high level of memory capacity is prerequisite for language and whether language origin could influence memory capacity. In line with evolutionary theories that natural selection refined language-related cognitive abilities, we advocated a coevolution scenario between language and memory capacity, which incorporated the genetic transmission of individual memory capacity, cultural transmission of idiolects, and natural and cultural selections on individual reproduction and language teaching. To illustrate the coevolution dynamics, we adopted a multi-agent computational model simulating the emergence of lexical items and simple syntax through iterated communications. Simulations showed that: along with the origin of a communal language, an initially-low memory capacity for acquired linguistic knowledge was boosted; and such coherent increase in linguistic understandability and memory capacities reflected a language-memory coevolution; and such coevolution stopped till memory capacities became sufficient for language communications. Statistical analyses revealed that the coevolution was realized mainly by natural selection based on individual communicative success in cultural transmissions. This work elaborated the biology-culture parallelism of language evolution, demonstrated the driving force of culturally-constituted factors for natural selection of individual cognitive abilities, and suggested that the degree difference in language-related cognitive abilities between humans and nonhuman animals could result from a coevolution with language.
Modeling Coevolution between Language and Memory Capacity during Language Origin
Gong, Tao; Shuai, Lan
2015-01-01
Memory is essential to many cognitive tasks including language. Apart from empirical studies of memory effects on language acquisition and use, there lack sufficient evolutionary explorations on whether a high level of memory capacity is prerequisite for language and whether language origin could influence memory capacity. In line with evolutionary theories that natural selection refined language-related cognitive abilities, we advocated a coevolution scenario between language and memory capacity, which incorporated the genetic transmission of individual memory capacity, cultural transmission of idiolects, and natural and cultural selections on individual reproduction and language teaching. To illustrate the coevolution dynamics, we adopted a multi-agent computational model simulating the emergence of lexical items and simple syntax through iterated communications. Simulations showed that: along with the origin of a communal language, an initially-low memory capacity for acquired linguistic knowledge was boosted; and such coherent increase in linguistic understandability and memory capacities reflected a language-memory coevolution; and such coevolution stopped till memory capacities became sufficient for language communications. Statistical analyses revealed that the coevolution was realized mainly by natural selection based on individual communicative success in cultural transmissions. This work elaborated the biology-culture parallelism of language evolution, demonstrated the driving force of culturally-constituted factors for natural selection of individual cognitive abilities, and suggested that the degree difference in language-related cognitive abilities between humans and nonhuman animals could result from a coevolution with language. PMID:26544876
Microscopic origin of shear relaxation in a model viscoelastic liquid.
Ashwin, J; Sen, Abhijit
2015-02-01
An atomistic description of shear stress relaxation in a viscoelastic liquid is developed from first principles through accurate molecular dynamic simulations in a model Yukawa system. It is shown that the relaxation time τ(M)(ex) of the excess part of the shear stress autocorrelation function provides a correct measure of the relaxation process. Below a certain critical value Γ(c) of the Coulomb coupling strength, the lifetime of local atomic connectivity τ(LC) converges to τ(M)(ex) and is the microscopic origin of the relaxation. At Γ≫Γ(c), i.e., in the potential energy dominated regime, τ(M)(ex)→τ(M) (the Maxwell relaxation time) and can, therefore, fully account for the elastic or "solidlike" behavior. Our results can help provide a better fundamental understanding of viscoelastic behavior in a variety of strongly coupled systems such as dusty plasmas, colloids, and non-Newtonian fluids.
Microscopic Origin of Shear Relaxation in a Model Viscoelastic Liquid
Ashwin, J.; Sen, Abhijit
2015-02-01
An atomistic description of shear stress relaxation in a viscoelastic liquid is developed from first principles through accurate molecular dynamic simulations in a model Yukawa system. It is shown that the relaxation time τMex of the excess part of the shear stress autocorrelation function provides a correct measure of the relaxation process. Below a certain critical value Γc of the Coulomb coupling strength, the lifetime of local atomic connectivity τLC converges to τMex and is the microscopic origin of the relaxation. At Γ ≫Γc, i.e., in the potential energy dominated regime, τMex→τM (the Maxwell relaxation time) and can, therefore, fully account for the elastic or "solidlike" behavior. Our results can help provide a better fundamental understanding of viscoelastic behavior in a variety of strongly coupled systems such as dusty plasmas, colloids, and non-Newtonian fluids.
The origins of agriculture in Iberia: a computational model
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Salvador Pardo Gordó
2015-12-01
Full Text Available Here we discuss the importance of using the rich and growing database of high-precision, audited radiocarbon dates for high-resolution bottom-up modelling to focus on problems concerning the spread of the Neolithic in the Iberia. We also compare the spread of the Late Mesolithic (so-called Geometric and the Early Neolithic using our modelling environment. Our results suggest that the source of radiocarbon data used to evaluate alternative hypotheses plays an important role in the results and open up new lines of research for the future.
Biotic origin for Mima mounds supported by numerical modeling
Gabet, Emmanuel J.; Perron, J. Taylor; Johnson, Donald L.
2014-02-01
Mima mounds are ~ 1-m-high hillocks found on every continent except Antarctica. Despite often numbering in the millions within a single field, their origin has been a mystery, with proposed explanations ranging from glacial processes to seismic shaking. One hypothesis proposes that mounds in North America are built by burrowing mammals to provide refuge from seasonally saturated soils. We test this hypothesis with a numerical model, parameterized with measurements of soil transport by gophers from a California mound field, that couples animal behavior with geomorphic processes. The model successfully simulates the development of the mounds as well as key details such as the creation of vernal pools, small intermound basins that provide habitat for endemic species. Furthermore, we demonstrate that the spatial structure of the modeled mound fields is similar to actual mound fields and provides an example of self-organized topographic features. We conclude that, scaled by body mass, Mima mounds are the largest structures built by nonhuman mammals and may provide a rare example of an evolutionary coupling between landforms and the organisms that create them.
Biotic Origin for Mima Mounds Supported by Numerical Model
Gabet, E. J.; Perron, J.; Johnson, D. L.
2013-12-01
Mima mounds are ~1-m-high hillocks found on every continent except Antarctica. Despite often numbering in the millions within a single field, their origin has been a mystery, with proposed explanations ranging from glacial processes to seismic shaking. One hypothesis proposes that mounds in North America are built by burrowing mammals to provide refuge from seasonally saturated soils. We test this hypothesis with a numerical model, parameterized with measurements of soil transport by gophers from a California mound field, that couples animal behavior with geomorphic processes. The model successfully simulates the development of the mounds, as well as key details such as the creation of vernal pools, small intermound basins that provide habitat for endemic species. Furthermore, we demonstrate that the spatial structure of the modeled mound fields is similar to actual mound fields and provides an example of self-organized topographic features. We conclude that, scaled by body mass, Mima mounds are the largest structures built by non-human mammals, and may provide a rare example of an evolutionary coupling between landforms and the organisms that create them.
Dynamical Models for the Origin of Iapetus' Dark Material
Tamayo, Daniel; Burns, J. A.; Denk, T.
2009-09-01
The stark albedo dichotomy on Iapetus has been known since 1671. Interestingly, recent Cassini ISS color observations have revealed a separate "color dichotomy"--color and slight albedo differences within the dark and within the bright terrains--seemingly determined by Iapetus’ orbital motion (Denk et al. 2009, Science, submitted). Spencer and Denk (2009, Science, submitted) have modeled how such a color dichotomy could result in thermally-driven runaway migration of water ice leading to the global albedo distribution observed today. This scenario seems very reasonable, but the (likely exogenous) source for the reddish material required to form the color dichotomy and initiate the runaway ice migration remains open. We model dust particles from all the irregular moons as the source for the dark material by numerically integrating the effect of radiation forces on their orbits and calculating their cumulative probability of collision with Iapetus. This work is an extension of Burns et al. (1996) aimed at resolving the inconsistencies mentioned therein with regard to the distribution and supply of dark material. We evaluate Soter's model (1974) proposing Phoebe as the source of the dark material, as well as models where dust originates from irregular moons discovered more recently. Our calculations show that only particles on high-eccentricity orbits (induced by radiation pressure) are capable of striking Iapetus. We will discuss such a model's implications for the longitudinal coverage of dark material, as well as the importance of thermal processes for the latitudinal segregation of ice. Finally, we will address whether Phoebe and the outer irregular satellites can collectively account for a sufficient supply of material to darken and redden the leading-side polar areas relative to their trailing-side counterparts, thereby creating the color dichotomy. This would initiate the proposed thermally-driven migration process and lead to the presently observed global
Full velocity difference and acceleration model for a car-following theory
Yu, Shaowei; Liu, Qingling; Li, Xiuhai
2013-05-01
In order to describe the car-following behavior more actually in real traffic, a full velocity difference and acceleration model (for short, FVDAM) is proposed by synthetically taking into account headway, velocity difference and acceleration of the leading car on the basis of full velocity difference model. The analytical method and numerical simulation results show that the proposed model can describe the phase transition of traffic flow and estimate the evolution of traffic congestion, that incorporating the acceleration of the leading car into car-following model can stabilize traffic flow, suppress the traffic jam and increase capacity, and that the following car in FVDAM can accelerate more quickly than in FVDM.
The use of model-test data for predicting full-scale ACV resistance
Forstell, B. G.; Harry, C. W.
The paper summarizes the analysis of test data obtained with a 1/12-scale model of the Amphibious Assault Landing Craft (AALC) JEFF(B). The analysis was conducted with the objective of improving the accuracy of drag predictions for a JEFF(B)-type air-cushion vehicle (ACV). Model test results, scaled to full-scale, are compared with full-scale drag obtained in various sea states during JEFF(B) trials. From the results of this comparison, it is found that the Froude-scale model rough-water drag data is consistently greater than full-scale derived drag, and is a function of both wave height and craft forward speed. Results are presented indicating that Froude scaling model data obtained in calm water also causes an over-prediction of calm-water drag at full-scale. An empirical correction that was developed for use on a JEFF(B)-type craft is discussed.
A Branch and Bound Method to the Continuous Time Model Elevator System with Full Information
Shen, Zhen; Zhao, Qianchuan
A new Branch and Bound method is given for the scheduling of the group elevator system with full information. Full information means that not only the parameters of the elevator systems but also the arrival time, origins and destinations of all the passengers who are to be served are known beforehand. The performance obtained by solving the full information problem is the best performance that the elevator scheduling algorithm can achieve and then can be used to measure how good an elevator scheduling algorithm is. The method can handle the continuous time event and is based on the concept of “trip”, which refers to the movement of the car without changing the direction and with at least one passenger being served.
Benchmark experiments for higher-order and full Stokes ice sheet models (ISMIP-HOM
Directory of Open Access Journals (Sweden)
F. Pattyn
2008-02-01
Full Text Available We present the results of the first ice sheet model intercomparison project for higher-order and full Stokes ice sheet models. These models are validated in a series of six benchmark experiments of which one has an analytical solution under simplifying assumptions. Five of the tests are diagnostic and one experiment is prognostic or time dependent, for both 2-D and 3-D geometries. The results show a good convergence of the different models even for high aspect ratios. A clear distinction can be made between higher-order models and those that solve the full system of equations. The latter show a significantly better agreement with each other as well as with analytical solutions, which demonstrates that they are hardly influenced by the used numerics.
Coenzyme world model of the origin of life.
Sharov, Alexei A
2016-06-01
The origin of life means the emergence of heritable and evolvable self-reproduction. However the mechanisms of primordial heredity were different from those in contemporary cells. Here I argue that primordial life had no nucleic acids; instead heritable signs were represented by isolated catalytically active self-reproducing molecules, similar to extant coenzymes, which presumably colonized surfaces of oil droplets in water. The model further assumes that coenzyme-like molecules (CLMs) changed surface properties of oil droplets (e.g., by oxidizing terminal carbons), and in this way created and sustained favorable conditions for their own self-reproduction. Such niche-dependent self-reproduction is a necessary condition for cooperation between different kinds of CLMs because they have to coexist in the same oil droplets and either succeed or perish together. Additional kinds of hereditary molecules were acquired via coalescence of oil droplets carrying different kinds of CLMs or via modification of already existing CLMs. Eventually, polymerization of CLMs became controlled by other polymers used as templates; and this kind of template-based synthesis eventually resulted in the emergence of RNA-like replicons. Apparently, oil droplets transformed into the outer membrane of cells via engulfing water, stabilization of the surface, and osmoregulation. In result, the metabolism was internalized allowing cells to accumulate free-floating resources (e.g., animoacids, ATP), which was a necessary condition for the development of protein synthesis. Thus, life originated from simple but already functional molecules, and its gradual evolution towards higher complexity was driven by cooperation and natural selection.
A full-wave Helmholtz model for continuous-wave ultrasound transmission.
Huttunen, Tomi; Malinen, Matti; Kaipio, Jari P; White, Phillip Jason; Hynynen, Kullervo
2005-03-01
A full-wave Helmholtz model of continuous-wave (CW) ultrasound fields may offer several attractive features over widely used partial-wave approximations. For example, many full-wave techniques can be easily adjusted for complex geometries, and multiple reflections of sound are automatically taken into account in the model. To date, however, the full-wave modeling of CW fields in general 3D geometries has been avoided due to the large computational cost associated with the numerical approximation of the Helmholtz equation. Recent developments in computing capacity together with improvements in finite element type modeling techniques are making possible wave simulations in 3D geometries which reach over tens of wavelengths. The aim of this study is to investigate the feasibility of a full-wave solution of the 3D Helmholtz equation for modeling of continuous-wave ultrasound fields in an inhomogeneous medium. The numerical approximation of the Helmholtz equation is computed using the ultraweak variational formulation (UWVF) method. In addition, an inverse problem technique is utilized to reconstruct the velocity distribution on the transducer which is used to model the sound source in the UWVF scheme. The modeling method is verified by comparing simulated and measured fields in the case of transmission of 531 kHz CW fields through layered plastic plates. The comparison shows a reasonable agreement between simulations and measurements at low angles of incidence but, due to mode conversion, the Helmholtz model becomes insufficient for simulating ultrasound fields in plates at large angles of incidence.
1D-3D Hybrid Modelling - From Multi-Compartment Models to Full Resolution Models in Space and Time
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Stephan eGrein
2014-07-01
Full Text Available Investigation of cellular and network dynamics in the brain by means of modeling & simulation has evolved into a highly interdisciplinary field, that uses sophisticated modeling & simulation approaches to understand distinct areas of brain function. Depending on the underlying complexity, these models vary in level of detail to cope with the attached computational cost. Hence for large network simulations, single neurons are typically reduced to time-dependent signal processors, dismissing spatial aspects of the cells. For single cell or small-world networks, general purpose simulators allow for space and time-dependent simulations of electrical signal processing, based on the cable equation theory. An emerging field in Computational Neuroscience encompasses a new level of detail by incorporating the 3D morphology of cells and organelles into 3D space and time-dependent simulations. Every approach has its advantages and limitations, such as computational cost, integrated and methods-spanning simulation approaches, depending on the network size could establish new ways to investigate the brain. We present a hybrid simulation approach, that makes use of reduced 1D-models using e.g. the NEURON which couples to fully resolved models for simulating cellular and sub-cellular dynamics, including the detailed 3D-morphology of neurons and organelles. To couple 1D- & 3D-simulations, we present a geometry and membrane potential mapping framework, with which graph-based morphologies, e.g. in swc-/hoc-format, are mapped to full surface and volume representations of the neuron; membrane potential data from 1D-simulations are used as boundary conditions for full 3D simulations. Thus, established models and data, based on general purpose 1D-simulators, can be directly coupled to the emerging field of fully resolved highly detailed 3D-modeling approaches. The new framework is applied to investigate electrically active neurons and their intracellular spatio
Photochirogenesis: Photochemical Models on the Origin of Biomolecular Homochirality
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Cornelia Meinert
2010-05-01
Full Text Available Current research focuses on a better understanding of the origin of biomolecular asymmetry by the identification and detection of the possibly first chiral molecules that were involved in the appearance and evolution of life on Earth. We have reasons to assume that these molecules were specific chiral amino acids. Chiral amino acids have been identified in both chondritic meteorites and simulated interstellar ices. Present research reasons that circularly polarized electromagnetic radiation was identified in interstellar environments and an asymmetric interstellar photon-molecule interaction might have triggered biomolecular symmetry breaking. We review on the possible prebiotic interaction of ‘chiral photons’ in the form of circularly polarized light, with early chiral organic molecules. We will highlight recent studies on enantioselective photolysis of racemic amino acids by circularly polarized light and experiments on the asymmetric photochemical synthesis of amino acids from only one C and one N containing molecules by simulating interstellar environments. Both approaches are based on circular dichroic transitions of amino acids that will be presented as well.
Sainath, Kamalesh
2015-01-01
We propose a full-wave pseudo-analytical numerical electromagnetic (EM) algorithm to model subsurface induction sensors, traversing planar-layered geological formations of arbitrary EM material anisotropy and loss, which are used, for example, in the exploration of hydrocarbon reserves. Unlike past pseudo-analytical planar-layered modeling algorithms that impose parallelism between the formation's bed junctions however, our method involves judicious employment of Transformation Optics techniques to address challenges related to modeling arbitrarily-oriented, relative slope (i.e., tilting) between said junctions. The algorithm exhibits this flexibility, both with respect to anisotropy in the formation layers as well as junction tilting, via employing special planar slabs that coat each "flattened" (i.e., originally tilted) planar interface, locally redirecting the incident wave within the coating slabs to cause wave fronts to interact with the flattened interfaces as if they were still tilted with a specific, ...
$\\gamma$-ray and X-ray luminosities from spin-powered pulsars in the full polar cap cascade model
Zhang, B; Zhang, Bing; Harding, Alice K.
2000-01-01
We modify the conventional curvature radiation (inverse Compton scattering) + synchrotron radiation polar cap cascade model by including the inverse Compton scattering of the higher generation pairs. Within the framework of the space-charge-limited-flow acceleration model with frame-dragging proposed by Harding & Muslimov (1998), such a full polar cap cascade scenario can well reproduce the $L_\\gamma \\propto (L_{\\rm sd})^{1/2}$ and the $L_x \\sim 10^{-3} L_{\\rm sd}$ dependences observed from the known spin-powered pulsars. According to this model, the ``pulsed'' soft ROSAT-band X-rays from most of the millisecond pulsars might be of thermal origin, if there are no strong multipole magnetic components near their surfaces.
Evaluation of Full Reynolds Stress Turbulence Models in FUN3D
Dudek, Julianne C.; Carlson, Jan-Renee
2017-01-01
Full seven-equation Reynolds stress turbulence models are a relatively new and promising tool for todays aerospace technology challenges. This paper uses two stress-omega full Reynolds stress models to evaluate challenging flows including shock-wave boundary layer interactions, separation and mixing layers. The Wilcox and the SSG/LRR full second-moment Reynolds stress models have been implemented into the FUN3D (Fully Unstructured Navier-Stokes Three Dimensional) unstructured Navier-Stokes code and are evaluated for four problems: a transonic two-dimensional diffuser, a supersonic axisymmetric compression corner, a compressible planar shear layer, and a subsonic axisymmetric jet. Simulation results are compared with experimental data and results using the more commonly used Spalart-Allmaras (SA) one-equation and the Menter Shear Stress Transport (SST-V) two-equation turbulence models.
Full Service ISDN Satellite (FSIS) network model for advanced ISDN satellite design and experiments
Pepin, Gerard R.
1992-01-01
The Full Service Integrated Services Digital Network (FSIS) network model for advanced satellite designs describes a model suitable for discrete event simulations. A top down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ACTS and the Interim Service ISDN Satellite (ISIS) perform ISDN protocol analyses and switching decisions in the terrestrial domain, whereas FSIS makes all its analyses and decisions on-board the ISDN satellite.
Studies to Improve the Science in the GAIM - Full Physics Model
2014-01-01
coupling at high latitudes (Zhu et al, 1993, 2000, 2005). The model is based on a numerical solution of the MHD transport equations and Ohm’s Law, with...title]Studies to Improve the Science in the GAIM - Full Physics Model [awardnumberl]N00014-09-l-0292 [awardnumber2] [awardnumbermore] [keywords...Ionospheric Dynamics and ElectroDynamics Data Assimilation (IDED-DA) model discovered new ionosphere phenomena, including a terminator current, plasma
CMS-Wave Model: Part 5. Full-plane Wave Transformation and Grid Nesting
2012-04-01
are available in previous reports and CHETNs (Lin et al. 2006; Demirbilek et al. 2007). CMS -Wave is part of the Coastal Modeling System ( CMS ...the U.S. Army Corps of Engineers’ (USACE) Surface-water Modeling System (SMS). The CMS -Wave FP option is available in SMS Version 11.1 and higher...ERDC/CHL CHETN-IV-81 April 2012 Approved for public release; distribution is unlimited. CMS -Wave Model: Part 5. Full-plane Wave Transformation
Development and Full Body Validation of a 5th Percentile Female Finite Element Model.
Davis, Matthew L; Koya, Bharath; Schap, Jeremy M; Gayzik, F Scott
2016-11-01
To mitigate the societal impact of vehicle crash, researchers are using a variety of tools, including finite element models (FEMs). As part of the Global Human Body Models Consortium (GHBMC) project, comprehensive medical image and anthropometrical data of the 5th percentile female (F05) were acquired for the explicit purpose of FEM development. The F05-O (occupant) FEM model consists of 981 parts, 2.6 million elements, 1.4 million nodes, and has a mass of 51.1 kg. The model was compared to experimental data in 10 validation cases ranging from localized rigid hub impacts to full body sled cases. In order to make direct comparisons to experimental data, which represent the mass of an average male, the model was compared to experimental corridors using two methods: 1) post-hoc scaling the outputs from the baseline F05-O model and 2) geometrically morphing the model to the body habitus of the average male to allow direct comparisons. This second step required running the morphed full body model in all 10 simulations for a total of 20 full body simulations presented. Overall, geometrically morphing the model was found to more closely match the target data with an average ISO score for the rigid impacts of 0.76 compared to 0.67 for the scaled responses. Based on these data, the morphed model was then used for model validation in the vehicle sled cases. Overall, the morphed model attained an average weighted score of 0.69 for the two sled impacts. Hard tissue injuries were also assessed and the baseline F05-O model was found to predict a greater occurrence of pelvic fractures compared to the GHBMC average male model, but predicted fewer rib fractures.
Chang, Jiang-Hao; Yu, Jing-Cun; Liu, Zhi-Xin
2016-09-01
The full-space transient electromagnetic response of water-filled goaves in coal mines were numerically modeled. Traditional numerical modeling methods cannot be used to simulate the underground full-space transient electromagnetic field. We used multiple transmitting loops instead of the traditional single transmitting loop to load the transmitting loop into Cartesian grids. We improved the method for calculating the z-component of the magnetic field based on the characteristics of full space. Then, we established the fullspace 3D geoelectrical model using geological data for coalmines. In addition, the transient electromagnetic responses of water-filled goaves of variable shape at different locations were simulated by using the finite-difference time-domain (FDTD) method. Moreover, we evaluated the apparent resistivity results. The numerical modeling results suggested that the resistivity differences between the coal seam and its roof and floor greatly affect the distribution of apparent resistivity, resulting in nearly circular contours with the roadway head at the center. The actual distribution of apparent resistivity for different geoelectrical models of water in goaves was consistent with the models. However, when the goaf water was located in one side, a false low-resistivity anomaly would appear on the other side owing to the full-space effect but the response was much weaker. Finally, the modeling results were subsequently confirmed by drilling, suggesting that the proposed method was effective.
Full-observability analysis and implementation of the general SLAM model
Souici, Ae.; Courdesses, M.; Ouldali, A.; Chatila, R.
2013-03-01
Simultaneous localisation and mapping (SLAM) problem is a non-linear system with dynamic state and measurement dimensions. The full observability of such system was ignored, in spite of the fact that system observability is a fundamental aspect in any state estimation problem. In this article, we present a full observability analysis of the general SLAM model. We show that known landmarks (anchor) solution does not guarantee full observability. Furthermore, we prove that to make the general SLAM model fully observable, a combination of known landmarks and invariant metrics are needed. Moreover, we propose a solution to implement a fully observable SLAM model based on mature landmark and virtual observation concepts. Simulations and experimental results are presented demonstrating the validity of the solutions in real world.
Object oriented Full Function Point Analysis: A Model for Real Time Application
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Sheeba Praveen
2012-09-01
Full Text Available this research work focused on determining the functional size of real time application at early stage. This paper will describe how to estimate the functional size of real time system using OO methodology. In this research we are proposing a Model which is very useful for estimating the size of real time system. And this model is fully based on Object oriented development Methodology due to the adaptation of the Function Point Analysis (FPA to Object Point Analysis (OPA. This model is for Real Time Application due to that have to take the FFP metric because FFP is best for size measurement of real time system. So the mapping is done in between Full Function Point metrics (FFP to Object Oriented Function Point metrics (OOFP and finally we are proposing a new metrics known as OOFFP and the based analysis is known as Object Oriented Full Function Point Analysis (OOFFPA.
A combined computational and structural model of the full-length human prolactin receptor
DEFF Research Database (Denmark)
Bugge, Katrine Østergaard; Papaleo, Elena; Haxholm, Gitte Wolfsberg
2016-01-01
-angle X-ray scattering, native mass spectrometry and NMR spectroscopy. Along with previously published data, these are integrated by molecular modelling to generate a full receptor structure. The result provides the first full view of a class I cytokine receptor, exemplifying the architecture of more than...... 40 different receptor chains, and reveals that the extracellular domain is merely the tip of a molecular iceberg....
Full-model wavenumber inversion: An emphasis on the appropriate wavenumber continuation
Alkhalifah, Tariq Ali
2016-04-06
A model of the earth can be described using a Fourier basis represented by its wavenumber content. In full-waveform inversion (FWI), the wavenumber description of the model is natural because our Born-approximation-based velocity updates are made up of wavefields. Our objective in FWI is to access all the model wavenumbers available in our limited aperture and bandwidth recorded data that are not yet accurately present in the initial velocity model. To invert for those model wavenumbers, we need to locate their imprint in the data. Thus, I review the relation between the model wavenumber buildup and the inversion process. Specifically, I emphasize a focus on the model wavenumber components and identified their individual influence on the data. Missing the energy for a single vertical low-model wavenumber from the residual between the true Marmousi model and some initial linearly increasing velocity model produced a worse least-squares fit to the data than the initial model itself, in which all the residual model wavenumbers were missing. This stern realization validated the importance of wavenumber continuation, specifically starting from the low-model wavenumbers, to higher (resolution) wavenumbers, especially those attained in an order dictated by the scattering angle filter. A numerical Marmousi example determined the important role that the scattering angle filter played in managing the wavenumber continuation from low to high. An application on the SEG2014 blind test data set with frequencies lower than 7 Hz muted out further validated the versatility of the scattering angle filtering.
Kirchner, N.; Ahlkrona, J.; Gowan, E. J.; Lötstedt, P.; Lea, J. M.; Noormets, R.; von Sydow, L.; Dowdeswell, J. A.; Benham, T.
2016-09-01
Full Stokes ice sheet models provide the most accurate description of ice sheet flow, and can therefore be used to reduce existing uncertainties in predicting the contribution of ice sheets to future sea level rise on centennial time-scales. The level of accuracy at which millennial time-scale palaeo-ice sheet simulations resolve ice sheet flow lags the standards set by Full Stokes models, especially, when Shallow Ice Approximation (SIA) models are used. Most models used in paleo-ice sheet modeling were developed at a time when computer power was very limited, and rely on several assumptions. At the time there was no means of verifying the assumptions by other than mathematical arguments. However, with the computer power and refined Full Stokes models available today, it is possible to test these assumptions numerically. In this paper, we review (Ahlkrona et al., 2013a) where such tests were performed and inaccuracies in commonly used arguments were found. We also summarize (Ahlkrona et al., 2013b) where the implications of the inaccurate assumptions are analyzed for two paleo-models - the SIA and the SOSIA. We review these works without resorting to mathematical detail, in order to make them accessible to a wider audience with a general interest in palaeo-ice sheet modelling. Specifically, we discuss two implications of relevance for palaeo-ice sheet modelling. First, classical SIA models are less accurate than assumed in their original derivation. Secondly, and contrary to previous recommendations, the SOSIA model is ruled out as a practicable tool for palaeo-ice sheet simulations. We conclude with an outlook concerning the new Ice Sheet Coupled Approximation Level (ISCAL) method presented in Ahlkrona et al. (2016), that has the potential to match the accuracy standards of full Stokes model on palaeo-timescales of tens of thousands of years, and to become an alternative to hybrid models currently used in palaeo-ice sheet modelling. The method is applied to an ice
Modelling of Peach Tree (Prunus persica) Full Blooming Dates Using APCC MME Seasonal Forecasts
Chun, Jong; Kim, Sung; Lee, Hyojin; Han, Hyun-Hee; Son, In-Chang; Cho, Kyung Hwa
2016-04-01
Due to global warming, recently, bud-burst and flowering dates of fruit crops have become earlier and the abnormal climate increases the variabilities of temperature in spring, suggesting that the risk of frost damage has increased. However, the full blooming date prediction model for peach tree used by the Rural Developmental Administration (RDA) were developed using only one cultivar (Youmyeong) and observations from a station (Suwon). This model might not adequately reflect the characteristics of peach cultivars or local orchards. the objectives of this study were to develops the site-and cultivar-specific blooming date prediction models for major peach cultivation regions and cultivars and presents a framework for applications of the APEC Climate Center Multimodel Ensemble (APCC MME) seasonal datasets.Developmental rate (DVR), and Sequential dormancy models (Chill day, New chill day, and fraction-time models) were used to develop the locally tailored full blooming date prediction models for major peach cultivars. For the development of these models, bud-burst and full blooming dates of peach tree for 5 cultivars (Cheonhong, Youmyeong, Changbangjosaeng, Cheonjoongdo, and Janghowon) were collected from the 6 major peach cultivation sites: Chuncheon, Suwon, Cheongwon, Cheongdo, Naju, and Jinju. For the chill day model, those measures for the entire dataset regardless the location and cultivar were 2.31%, 0.79, and 3.36 day for MAPE, R2, RMSE, respectively. For the new chill day model, those values (2.19%, 0.82, and 3.16 day for MAPE, R2, RMSE, respectively) were slightly better than those of the chill day model. The model results showed that the new chill day model was found slightly highest performance than others. Based on the considerations of the predictability of the statistical downscaling method and the observed periods of the full blooming dates at each site, we determined that the APCC MME seasonal datasets were applied for the new chill day model for the
A physical resist shrinkage model for full-chip lithography simulations
Liu, Peng; Zheng, Leiwu; Ma, Maggie; Zhao, Qian; Fan, Yongfa; Zhang, Qiang; Feng, Mu; Guo, Xin; Wallow, Tom; Gronlund, Keith; Goossens, Ronald; Zhang, Gary; Lu, Yenwen
2016-03-01
Strong resist shrinkage effects have been widely observed in resist profiles after negative tone development (NTD) and therefore must be taken into account in computational lithography applications. However, existing lithography simulation tools, especially those designed for full-chip applications, lack resist shrinkage modeling capabilities because they are not needed until only recently when NTD processes begin to replace the conventional positive tone development (PTD) processes where resist shrinkage effects are negligible. In this work we describe the development of a physical resist shrinkage (PRS) model for full-chip lithography simulations and present its accuracy evaluation against experimental data.
Energy Technology Data Exchange (ETDEWEB)
Sprigg, James A.; Ehlen, Mark Andrew
2004-11-01
Acts of terrorism could have a range of broad impacts on an economy, including changes in consumer (or demand) confidence and the ability of productive sectors to respond to changes. As a first step toward a model of terrorism-based impacts, we develop here a model of production and employment that characterizes dynamics in ways useful toward understanding how terrorism-based shocks could propagate through the economy; subsequent models will introduce the role of savings and investment into the economy. We use Aspen, a powerful economic modeling tool developed at Sandia, to demonstrate for validation purposes that a single-firm economy converges to the known monopoly equilibrium price, output, and employment levels, while multiple-firm economies converge toward the competitive equilibria typified by lower prices and higher output and employment. However, we find that competition also leads to churn by consumers seeking lower prices, making it difficult for firms to optimize with respect to wages, prices, and employment levels. Thus, competitive firms generate market ''noise'' in the steady state as they search for prices and employment levels that will maximize profits. In the context of this model, not only could terrorism depress overall consumer confidence and economic activity but terrorist acts could also cause normal short-run dynamics to be misinterpreted by consumers as a faltering economy.
Evaluation of Full Reynolds Stress Turbulence Models in FUN3D
Dudek, Julianne C.; Carlson, Jan-Renee
2017-01-01
Full seven-equation Reynolds stress turbulence models are promising tools for today’s aerospace technology challenges. This paper examines two such models for computing challenging turbulent flows including shock-wave boundary layer interactions, separation and mixing layers. The Wilcox and the SSG/LRR full second-moment Reynolds stress models have been implemented into the FUN3D (Fully Unstructured Navier-Stokes Three Dimensional) unstructured Navier-Stokes code and were evaluated for four problems: a transonic two-dimensional diffuser, a supersonic axisymmetric compression corner, a compressible planar shear layer, and a subsonic axisymmetric jet. Simulation results are compared with experimental data and results computed using the more commonly used Spalart-Allmaras (SA) one-equation and the Menter Shear Stress Transport (SST-V) two-equation turbulence models.
The stability analysis of the full velocity and acceleration velocity model
Xiaomei, Zhao; Ziyou, Gao
2007-03-01
The stability analysis is one of the important problems in the traffic flow theory, since the congestion phenomena can be regarded as the instability and the phase transition of a dynamical system. Theoretically, we analyze the stable conditions of the full velocity and acceleration difference model (FVADM), which is proposed by introducing the acceleration difference term based on the previous car-following models (the optimal velocity model and the full velocity difference model, OVM and FVDM). By numerical simulations, it is found that when the traffic flow is unstable, the traffic jam in the FVADM is weaker than that in the FVDM. Also it is observed that the spreading speed of the jam is slower in the FVADM than that in the FVDM and the fluctuations of vehicles in the FVADM are smaller than those in the FVDM. Therefore, the acceleration difference term has strong effects on traffic dynamics and plays an important role in stabilizing the traffic flow.
Model independent WIMP Searches in full Simulation of the ILD Detector
Bartels, Christoph
2010-01-01
In this study the ILC's capabilities for detecting WIMPs and measure their properties are investigated. The signal events are detected by associated production of Initial State Radiation (ISR). A model independent formulation of the signal cross section is used. The cross section is normalized by inference from the observed abundance of cosmological Dark Matter (DM). The study is performed in full simulation of the ILD00 detector model. The prospects of determining the WIMP parameters individually and simultaneously are presented.
Exact solutions of a Flat Full Causal Bulk viscous FRW cosmological model through factorization
Cornejo-Pérez, O
2012-01-01
We study the classical flat full causal bulk viscous FRW cosmological model through the factorization method. The method allows to find some new exact parametric solutions for different values of the viscous parameter $s$. Special attention is given to the well known case $s=1/2$, for which the cosmological model admits scaling symmetries. Also, some exact parametric solutions for $s=1/2$ are obtained through the Lie group method.
Development of a full ice-cream cone model for halo CME structures
Na, Hyeonock; Moon, Yong-Jae
2015-04-01
The determination of three dimensional parameters (e.g., radial speed, angular width, source location) of Coronal Mass Ejections (CMEs) is very important for space weather forecast. To estimate these parameters, several cone models based on a flat cone or a shallow ice-cream cone with spherical front have been suggested. In this study, we investigate which cone model is proper for halo CME morphology using 33 CMEs which are identified as halo CMEs by one spacecraft (SOHO or STEREO-A or B) and as limb CMEs by the other ones. From geometrical parameters of these CMEs such as their front curvature, we find that near full ice-cream cone CMEs (28 events) are dominant over shallow ice-cream cone CMEs (5 events). So we develop a new full ice-cream cone model by assuming that a full ice-cream cone consists of many flat cones with different heights and angular widths. This model is carried out by the following steps: (1) construct a cone for given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, (4) minimize the difference between the estimated projection points with the observed ones. We apply this model to several halo CMEs and compare the results with those from other methods such as a Graduated Cylindrical Shell model and a geometrical triangulation method.
Calibration of multiple Kinect depth sensors for full surface model reconstruction
Tsui, Kwan Pang; Wong, Kin Hong; Wang, Changling; Kam, Ho Chuen; Yau, Hing Tuen; Yu, Ying Kin
2016-07-01
In this paper, we have investigated different methods to calibrate a 3-D scanning system consisting of multiple Kinect sensors. The main function of the scanning system is for the reconstruction of the full surface model of an object. In this work, we build a four-Kinect system that the Kinect range sensors are positioned around the target object. Each Kinect is responsible for capturing a small local model, and the local models found will be combined to become the full model. To build such a system, calibration of the poses among the Kinects is essential. We have tested a number of methods: using (1) a sphere, (2) a checker board and (3) a cube as the calibration object. After calibration, the results of method (1) and (2) are used in the multiple Kinect system for obtaining the 3-D model of a real object. Results are shown and compared. For method (3) we only performed the simulation test on finding the rotation between two Kinects and the result is promising. This is the first part of a long term project on building a full surface model capturing system. Such a system should be useful in robot vision, scientific research and many other industrial applications.
Determination of CME 3D parameters based on a new full ice-cream cone model
Na, Hyeonock; Moon, Yong-Jae
2017-08-01
In space weather forecast, it is important to determine three-dimensional properties of CMEs. Using 29 limb CMEs, we examine which cone type is close to a CME three-dimensional structure. We find that most CMEs have near full ice-cream cone structure which is a symmetrical circular cone combined with a hemisphere. We develop a full ice-cream cone model based on a new methodology that the full ice-cream cone consists of many flat cones with different heights and angular widths. By applying this model to 12 SOHO/LASCO halo CMEs, we find that 3D parameters from our method are similar to those from other stereoscopic methods (i.e., a triangulation method and a Graduated Cylindrical Shell model). In addition, we derive CME mean density (ρmean=Mtotal/Vcone) based on the full ice-cream cone structure. For several limb events, we determine CME mass by applying the Solarsoft procedure (e.g., cme_mass.pro) to SOHO/LASCO C3 images. CME volumes are estimated from the full ice-cream cone structure. From the power-law relationship between CME mean density and its height, we estimate CME mean densities at 20 solar radii (Rs). We will compare the CME densities at 20 Rs with their corresponding ICME densities.
Research Note: Full-waveform inversion of the unwrapped phase of a model
Alkhalifah, Tariq Ali
2013-12-06
Reflections in seismic data induce serious non-linearity in the objective function of full- waveform inversion. Thus, without a good initial velocity model that can produce reflections within a half cycle of the frequency used in the inversion, convergence to a solution becomes difficult. As a result, we tend to invert for refracted events and damp reflections in data. Reflection induced non-linearity stems from cycle skipping between the imprint of the true model in observed data and the predicted model in synthesized data. Inverting for the phase of the model allows us to address this problem by avoiding the source of non-linearity, the phase wrapping phenomena. Most of the information related to the location (or depths) of interfaces is embedded in the phase component of a model, mainly influenced by the background model, while the velocity-contrast information (responsible for the reflection energy) is mainly embedded in the amplitude component. In combination with unwrapping the phase of data, which mitigates the non-linearity introduced by the source function, I develop a framework to invert for the unwrapped phase of a model, represented by the instantaneous depth, using the unwrapped phase of the data. The resulting gradient function provides a mechanism to non-linearly update the velocity model by applying mainly phase shifts to the model. In using the instantaneous depth as a model parameter, we keep track of the model properties unfazed by the wrapping phenomena. © 2013 European Association of Geoscientists & Engineers.
CUDA GPU based full-Stokes finite difference modelling of glaciers
DEFF Research Database (Denmark)
Brædstrup, Christian; Egholm, D.L.
Many have stressed the limitations of using the shallow shelf and shallow ice approxima- tions when modelling ice streams or surging glaciers. Using a full-stokes approach requires either large amounts of computer power or time and is therefore seldom an option for most glaciologists. Recent adva...
Enders, Craig K.
2001-01-01
Examined the performance of a recently available full information maximum likelihood (FIML) estimator in a multiple regression model with missing data using Monte Carlo simulation and considering the effects of four independent variables. Results indicate that FIML estimation was superior to that of three ad hoc techniques, with less bias and less…
The Role of Stochastic Models in Interpreting the Origins of Biological Chirality
Directory of Open Access Journals (Sweden)
Gábor Lente
2010-04-01
Full Text Available This review summarizes recent stochastic modeling efforts in the theoretical research aimed at interpreting the origins of biological chirality. Stochastic kinetic models, especially those based on the continuous time discrete state approach, have great potential in modeling absolute asymmetric reactions, experimental examples of which have been reported in the past decade. An overview of the relevant mathematical background is given and several examples are presented to show how the significant numerical problems characteristic of the use of stochastic models can be overcome by non-trivial, but elementary algebra. In these stochastic models, a particulate view of matter is used rather than the concentration-based view of traditional chemical kinetics using continuous functions to describe the properties system. This has the advantage of giving adequate description of single-molecule events, which were probably important in the origin of biological chirality. The presented models can interpret and predict the random distribution of enantiomeric excess among repetitive experiments, which is the most striking feature of absolute asymmetric reactions. It is argued that the use of the stochastic kinetic approach should be much more widespread in the relevant literature.
Experimental Analysis and Full Prediction Model of a 5-DOF Motorized Spindle
Directory of Open Access Journals (Sweden)
Weiyu Zhang
2017-01-01
Full Text Available The cost and power consumption of DC power amplifiers are much greater than that of AC power converters. Compared to a motorized spindle supported with DC magnetic bearings, a motorized spindle supported with AC magnetic bearings is inexpensive and more efficient. This paper studies a five-degrees-of-freedom (5-DOF motorized spindle supported with AC hybrid magnetic bearings (HMBs. Most models of suspension forces, except a “switching model”, are quite accurate, but only in a particular operating area and not in regional coverage. If a “switching model” is applied to a 5-DOF motorized spindle, the real-time performance of the control system can be significantly decreased due to the large amount of data processing for both displacement and current. In order to solve this defect, experiments based on the “switching model” are performed, and the resulting data are analyzed. Using the data analysis results, a “full prediction model” based on the operating state is proposed to improve real-time performance and precision. Finally, comparative, verification and stiffness tests are conducted to verify the improvement of the proposed model. Results of the tests indicate that the rotor has excellent characteristics, such as good real-time performance, superior anti-interference performance with load and the accuracy of the model in full zone. The satisfactory experimental results demonstrate the effectiveness of the “full prediction model” applied to the control system under different operating stages. Therefore, the results of the experimental analysis and the proposed full prediction model can provide a control system of a 5-DOF motorized spindle with the most suitable mathematical models of the suspension force.
Directory of Open Access Journals (Sweden)
G. Broström
2011-11-01
Full Text Available Oil spill modeling is considered to be an important part of a decision support system (DeSS for oil spill combatment and is useful for remedial action in case of accidents, as well as for designing the environmental monitoring system that is frequently set up after major accidents. Many accidents take place in coastal areas, implying that low resolution basin scale ocean models are of limited use for predicting the trajectories of an oil spill. In this study, we target the oil spill in connection with the "Full City" accident on the Norwegian south coast and compare operational simulations from three different oil spill models for the area. The result of the analysis is that all models do a satisfactory job. The "standard" operational model for the area is shown to have severe flaws, but by applying ocean forcing data of higher resolution (1.5 km resolution, the model system shows results that compare well with observations. The study also shows that an ensemble of results from the three different models is useful when predicting/analyzing oil spill in coastal areas.
Original article Rehabilitation model program for seriously ill patients
Directory of Open Access Journals (Sweden)
Adrienne Kegye
2014-10-01
Full Text Available Background Patients receiving cancer treatment start lifestyle changes mostly at the end of the treatment during the rehabilitation period. Most often, the first step is a dietary change and physical exercises built into the daily routine. Patients who do this in groups led by qualified therapists and based on professional counseling can build more effective and more permanent changes into their life. To develop a complex rehabilitation program which, in the short term, aims to familiarize patients with a lifestyle which harmonizes the physical, mental, spiritual and social spheres of life and, in the long term, to build it into their everyday life in order to ameliorate the physical and mental state and reduce the psychological symptoms and the isolation of patients. The physical component focuses on diet and exercise. The psycho-social-spiritual support focuses on discovering inner sources of strength, developing active coping mechanisms and helping to achieve more open communication. Participants and procedure In February and March 2011, 8 patients treated for malignant tumors participated in the model program. The components of the model program were psychotherapy, physiotherapy, cancer consultation, nutrition counseling, creative activities and walking. Results During the period of the model program the isolation of the patients decreased and their social support and ability of coping with the illness ameliorated. They reported an ease in anxiety and depression in their everyday activities. According to feedback, their communication with each other, with the staff and with their relatives became more open. Altogether this had advantageous effects on the functioning of the ward and the mood of the staff. Conclusions The rehabilitation program confirmed that beside individual psycho-social support, beneficial and economic psycho-social support can be provided for the patients in group form along with the most effective assignment of the
Monte Carlo study of single-barrier structure based on exclusion model full counting statistics
Institute of Scientific and Technical Information of China (English)
Chen Hua; Du Lei; Qu Cheng-Li; He Liang; Chen Wen-Hao; Sun Peng
2011-01-01
Different from the usual full counting statistics theoretical work that focuses on the higher order cumulants computation by using cumulant generating function in electrical structures, Monte Carlo simulation of single-barrier structure is performed to obtain time series for two types of widely applicable exclusion models, counter-flows model,and tunnel model. With high-order spectrum analysis of Matlab, the validation of Monte Carlo methods is shown through the extracted first four cumulants from the time series, which are in agreement with those from cumulant generating function. After the comparison between the counter-flows model and the tunnel model in a single barrier structure, it is found that the essential difference between them consists in the strictly holding of Pauli principle in the former and in the statistical consideration of Pauli principle in the latter.
Garth, Thomas; Rietbrock, Andreas; Hicks, Steve; Fuenzalida Velasco, Amaya; Casarotti, Emanuele; Spinuso, Alessandro
2015-04-01
The VERCE platform is an online portal that allows full waveform simulations to be run for any region where a suitable velocity model exists. We use this facility to simulate the waveforms from aftershock earthquakes from the 2014 Pisagua earthquake, and 2010 Maule earthquake that occurred at the subduction zone mega thrust in Northern and Central Chile respectively. Simulations are performed using focal mechanisms from both global earthquake catalogues, and regional earthquake catalogues. The VERCE platform supports specFEM Cartesian, and simulations are run using meshes produced by CUBIT. The full waveform modelling techniques supported on the VERCE platform are used to test the validity of a number of subduction zone velocity models from the Chilean subduction zone. For the Maule earthquake we use a 2D and 3D travel time tomography model of the rupture area (Hicks et al. 2011; 2014). For the Pisagua earthquake we test a 2D/3D composite velocity model based on tomographic studies of the region (e.g. Husen et al. 2000, Contreyes-Reyes et al. 2012) and slab1.0 (Hayes et al. 2012). Focal mechanisms from the cGMT catalogue and local focal mechanisms calculated using ISOLA (e.g. Agurto et al. 2012) are used in the simulations. The waveforms produced are directly compared to waveforms recorded on the temporary deployment for the Maule earthquake aftershocks, and waveforms recorded on the IPOC network for the Pisagua earthquake aftershocks. This work demonstrates how the VERCE platform allows waveforms from the full 3D simulations to be easily produced, allowing us to quantify the validity of both the velocity model and the source mechanisms. These simulations therefore provide an independent test of the velocity models produced synthetically and by travel time tomography studies. Initial results show that the waveform is reasonably well reproduced in the 0.05 - 0.25 frequency band using a refined 3D travel time tomography, and locally calculated focal mechanisms.
Semiactive Self-Tuning Fuzzy Logic Control of Full Vehicle Model with MR Damper
Directory of Open Access Journals (Sweden)
Mahmut Paksoy
2014-09-01
Full Text Available Intelligent controllers are studied for vibration reduction of a vehicle consisting in a semiactive suspension system with a magnetorheological(MR damper. The vehicle is modeled with seven degrees of freedom as a full vehicle model. The semiactive suspension system consists of a linear spring and an MR damper. MR damper is modeled using Bouc-Wen hysteresis phenomenon and applied to a full vehicle model. Fuzzy Logic based controllers are designed to determine the MR damper voltage. Fuzzy Logic and Self-Tuning Fuzzy Logic controllers are applied to the semiactive suspension system. Results of the system are investigated by simulation studies in MATLAB-Simulink environment. The performance of the semiactive suspension system is analyzed with and without control. Simulation results showed that both Fuzzy Logic and Self-Tuning Fuzzy Logic controllers perform better compared to uncontrolled case. Furthermore, Self-Tuning Fuzzy Logic controller displayed a greater improvement in vibration reduction performance compared to Fuzzy Logic controller.
Error modeling and tolerance design of a parallel manipulator with full-circle rotation
Directory of Open Access Journals (Sweden)
Yanbing Ni
2016-05-01
Full Text Available A method for improving the accuracy of a parallel manipulator with full-circle rotation is systematically investigated in this work via kinematic analysis, error modeling, sensitivity analysis, and tolerance allocation. First, a kinematic analysis of the mechanism is made using the space vector chain method. Using the results as a basis, an error model is formulated considering the main error sources. Position and orientation error-mapping models are established by mathematical transformation of the parallelogram structure characteristics. Second, a sensitivity analysis is performed on the geometric error sources. A global sensitivity evaluation index is proposed to evaluate the contribution of the geometric errors to the accuracy of the end-effector. The analysis results provide a theoretical basis for the allocation of tolerances to the parts of the mechanical design. Finally, based on the results of the sensitivity analysis, the design of the tolerances can be solved as a nonlinearly constrained optimization problem. A genetic algorithm is applied to carry out the allocation of the manufacturing tolerances of the parts. Accordingly, the tolerance ranges for nine kinds of geometrical error sources are obtained. The achievements made in this work can also be applied to other similar parallel mechanisms with full-circle rotation to improve error modeling and design accuracy.
Toward a full-scale computational model of the rat dentate gyrus.
Schneider, Calvin J; Bezaire, Marianne; Soltesz, Ivan
2012-01-01
Recent advances in parallel computing, including the creation of the parallel version of the NEURON simulation environment, have allowed for a previously unattainable level of complexity and detail in neural network models. Previously, we published a functional NEURON model of the rat dentate gyrus with over 50,000 biophysically realistic, multicompartmental neurons, but network simulations could only utilize a single processor. By converting the model to take advantage of parallel NEURON, we are now able to utilize greater computational resources and are able to simulate the full-scale dentate gyrus, containing over a million neurons. This has eliminated the previous necessity for scaling adjustments and allowed for a more direct comparison to experimental techniques and results. The translation to parallel computing has provided a superlinear speedup of computation time and dramatically increased the overall computer memory available to the model. The incorporation of additional computational resources has allowed for more detail and elements to be included in the model, bringing the model closer to a more complete and accurate representation of the biological dentate gyrus. As an example of a major step toward an increasingly accurate representation of the biological dentate gyrus, we discuss the incorporation of realistic granule cell dendrites into the model. Our previous model contained simplified, two-dimensional dendritic morphologies that were identical for neurons of the same class. Using the software tools L-Neuron and L-Measure, we are able to introduce cell-to-cell variability by generating detailed, three-dimensional granule cell morphologies that are based on biological reconstructions. Through these and other improvements, we aim to construct a more complete full-scale model of the rat dentate gyrus, to provide a better tool to delineate the functional role of cell types within the dentate gyrus and their pathological changes observed in epilepsy.
Determination of HCME 3-D parameters using a full ice-cream cone model
Na, Hyeonock; Moon, Yong-Jae; Lee, Harim
2016-05-01
It is very essential to determine three dimensional parameters (e.g., radial speed, angular width, source location) of Coronal Mass Ejections (CMEs) for space weather forecast. Several cone models (e.g., an elliptical cone model, an ice-cream cone model, an asymmetric cone model) have been examined to estimate these parameters. In this study, we investigate which cone type is close to a halo CME morphology using 26 CMEs: halo CMEs by one spacecraft (SOHO or STEREO-A or B) and as limb CMEs by the other ones. From cone shape parameters of these CMEs such as their front curvature, we find that near full ice-cream cone type CMEs are much closer to observations than shallow ice-cream cone type CMEs. Thus we develop a new cone model in which a full ice-cream cone consists of many flat cones with different heights and angular widths. This model is carried out by the following steps: (1) construct a cone for given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, and (4) minimize the difference between the estimated projection speeds with the observed ones. By applying this model to 12 SOHO/LASCO halo CMEs, we find that 3-D parameters from our method are similar to those from other stereoscopic methods (a geometrical triangulation method and a Graduated Cylindrical Shell model) based on multi-spacecraft data. We are developing a general ice-cream cone model whose front shape is a free parameter determined by observations.
On the influence of model parametrization in elastic full waveform tomography
Köhn, D.; De Nil, D.; Kurzmann, A.; Przebindowska, A.; Bohlen, T.
2012-10-01
Elastic Full Waveform Tomography (FWT) aims to reduce the misfit between recorded and modelled data, to deduce a very detailed model of elastic material parameters in the underground. The choice of the elastic model parameters to be inverted affects the convergence and quality of the reconstructed subsurface model. Using the Cross-Triangle-Squares (CTS) model three elastic parametrizations, Lamé parameters m1 = [λ, μ, ρ], seismic velocities m2 = [Vp, Vs, ρ] and seismic impedances m3 = [Ip, Is, ρ] for far-offset reflection seismic acquisition geometries with explosive point sources and free-surface condition are studied. In each CTS model the three elastic parameters are assigned to three different geometrical objects that are spatially separated. The results of the CTS model study reveal a strong requirement of a sequential frequency inversion from low to high frequencies to reconstruct the density model. Using only high-frequency data, cross-talk artefacts have an influence on the quantitative reconstruction of the material parameters, while for a sequential frequency inversion only structural artefacts, representing the boundaries of different model parameters, are present. During the inversion, the Lamé parameters, seismic velocities and impedances could be reconstructed well. However, using the Lamé parametrization ?-artefacts are present in the λ model, while similar artefacts are suppressed when using seismic velocities or impedances. The density inversion shows the largest ambiguity for all parametrizations. However, the artefacts are again more dominant, when using the Lamé parameters and suppressed for seismic velocity and impedance parametrization. The afore mentioned results are confirmed for a geologically more realistic modified Marmousi-II model. Using a conventional streamer acquisition geometry the P-velocity, S-velocity and density models of the subsurface were reconstructed successfully and are compared with the results of the Lam
Full wave model of image formation in optical coherence tomography applicable to general samples.
Munro, Peter R T; Curatolo, Andrea; Sampson, David D
2015-02-09
We demonstrate a highly realistic model of optical coherence tomography, based on an existing model of coherent optical microscopes, which employs a full wave description of light. A defining feature of the model is the decoupling of the key functions of an optical coherence tomography system: sample illumination, light-sample interaction and the collection of light scattered by the sample. We show how such a model can be implemented using the finite-difference time-domain method to model light propagation in general samples. The model employs vectorial focussing theory to represent the optical system and, thus, incorporates general illumination beam types and detection optics. To demonstrate its versatility, we model image formation of a stratified medium, a numerical point-spread function phantom and a numerical phantom, based upon a physical three-dimensional structured phantom employed in our laboratory. We show that simulated images compare well with experimental images of a three-dimensional structured phantom. Such a model provides a powerful means to advance all aspects of optical coherence tomography imaging.
Broström, G.; Carrasco, A.; Hole, L. R.; Dick, S.; Janssen, F.; Mattsson, J.; Berger, S.
2011-06-01
Oil spill modeling is considered to be an important decision support system (DeSS) useful for remedial action in case of accidents, as well as for designing the environmental monitoring system that is frequently set up after major accidents. Many accidents take place in coastal areas implying that low resolution basin scale ocean models is of limited use for predicting the trajectories of an oil spill. In this study, we target the oil spill in connection with the Full City accident on the Norwegian south coast and compare three different oil spill models for the area. The result of the analysis is that all models do a satisfactory job. The "standard" operational model for the area is shown to have severe flaws but including an analysis based on a higher resolution model (1.5 km resolution) for the area the model system show results that compare well with observations. The study also shows that an ensemble using three different models is useful when predicting/analyzing oil spill in coastal areas.
Common mode noise modeling and its suppression in ultra-high efficiency full bridge boost converter
DEFF Research Database (Denmark)
Makda, Ishtiyaq Ahmed; Nymand, Morten; Madawala, Udaya
2013-01-01
In this paper, common mode noise modeling of low-voltage high-current isolated full bridge boost dc-dc converters intended for fuel cell application is presented. Due to the tightly coupled primary and secondary windings of the transformer, such converter has inherently large capacitive coupling...... between input and output which is normally associated with high common mode noise generation. In this work, common mode noise sources in the converter are identified, and a common mode noise model is developed. Based on the established noise model, a practical CM filter is designed to comply...... with the CISPR-A requirements. Finally, a 3kW dc-dc converter including filters has been built and tested to verify the theoretical model. Experimental results confirm the theoretical analysis of the converter....
A validated computational model for the design of surface textures in full-film lubricated sliding
Schuh, Jonathon; Lee, Yong Hoon; Allison, James; Ewoldt, Randy
2016-11-01
Our recent experimental work showed that asymmetry is needed for surface textures to decrease friction in full-film lubricated sliding (thrust bearings) with Newtonian fluids; textures reduce the shear load and produce a separating normal force. The sign of the separating normal force is not predicted by previous 1-D theories. Here we model the flow with the Reynolds equation in cylindrical coordinates, numerically implemented with a pseudo-spectral method. The model predictions match experiments, rationalize the sign of the normal force, and allow for design of surface texture geometry. To minimize sliding friction with angled cylindrical textures, an optimal angle of asymmetry β exists. The optimal angle depends on the film thickness but not the sliding velocity within the applicable range of the model. The model has also been used to optimize generalized surface texture topography while satisfying manufacturability constraints.
Some guidance on preparing validation plans for the DART Full System Models.
Energy Technology Data Exchange (ETDEWEB)
Gray, Genetha Anne; Hough, Patricia Diane; Hills, Richard Guy (Sandia National Laboratories, Albuquerque, NM)
2009-03-01
Planning is an important part of computational model verification and validation (V&V) and the requisite planning document is vital for effectively executing the plan. The document provides a means of communicating intent to the typically large group of people, from program management to analysts to test engineers, who must work together to complete the validation activities. This report provides guidelines for writing a validation plan. It describes the components of such a plan and includes important references and resources. While the initial target audience is the DART Full System Model teams in the nuclear weapons program, the guidelines are generally applicable to other modeling efforts. Our goal in writing this document is to provide a framework for consistency in validation plans across weapon systems, different types of models, and different scenarios. Specific details contained in any given validation plan will vary according to application requirements and available resources.
Full-Scale Approximations of Spatio-Temporal Covariance Models for Large Datasets
Zhang, Bohai
2014-01-01
Various continuously-indexed spatio-temporal process models have been constructed to characterize spatio-temporal dependence structures, but the computational complexity for model fitting and predictions grows in a cubic order with the size of dataset and application of such models is not feasible for large datasets. This article extends the full-scale approximation (FSA) approach by Sang and Huang (2012) to the spatio-temporal context to reduce computational complexity. A reversible jump Markov chain Monte Carlo (RJMCMC) algorithm is proposed to select knots automatically from a discrete set of spatio-temporal points. Our approach is applicable to nonseparable and nonstationary spatio-temporal covariance models. We illustrate the effectiveness of our method through simulation experiments and application to an ozone measurement dataset.
Full Stokes finite-element modeling of ice sheets using a graphics processing unit
Seddik, H.; Greve, R.
2016-12-01
Thermo-mechanical simulation of ice sheets is an important approach to understand and predict their evolution in a changing climate. For that purpose, higher order (e.g., ISSM, BISICLES) and full Stokes (e.g., Elmer/Ice, http://elmerice.elmerfem.org) models are increasingly used to more accurately model the flow of entire ice sheets. In parallel to this development, the rapidly improving performance and capabilities of Graphics Processing Units (GPUs) allows to efficiently offload more calculations of complex and computationally demanding problems on those devices. Thus, in order to continue the trend of using full Stokes models with greater resolutions, using GPUs should be considered for the implementation of ice sheet models. We developed the GPU-accelerated ice-sheet model Sainō. Sainō is an Elmer (http://www.csc.fi/english/pages/elmer) derivative implemented in Objective-C which solves the full Stokes equations with the finite element method. It uses the standard OpenCL language (http://www.khronos.org/opencl/) to offload the assembly of the finite element matrix on the GPU. A mesh-coloring scheme is used so that elements with the same color (non-sharing nodes) are assembled in parallel on the GPU without the need for synchronization primitives. The current implementation shows that, for the ISMIP-HOM experiment A, during the matrix assembly in double precision with 8000, 87,500 and 252,000 brick elements, Sainō is respectively 2x, 10x and 14x faster than Elmer/Ice (when both models are run on a single processing unit). In single precision, Sainō is even 3x, 20x and 25x faster than Elmer/Ice. A detailed description of the comparative results between Sainō and Elmer/Ice will be presented, and further perspectives in optimization and the limitations of the current implementation.
Metabolic modelling of full-scale enhanced biological phosphorus removal sludge.
Lanham, Ana B; Oehmen, Adrian; Saunders, Aaron M; Carvalho, Gilda; Nielsen, Per H; Reis, Maria A M
2014-12-01
This study investigates, for the first time, the application of metabolic models incorporating polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) towards describing the biochemical transformations of full-scale enhanced biological phosphorus removal (EBPR) activated sludge from wastewater treatment plants (WWTPs). For this purpose, it was required to modify previous metabolic models applied to lab-scale systems by incorporating the anaerobic utilisation of the TCA cycle and the aerobic maintenance processes based on sequential utilisation of polyhydroxyalkanoates, followed by glycogen and polyphosphate. The abundance of the PAO and GAO populations quantified by fluorescence in situ hybridisation served as the initial conditions of each biomass fraction, whereby the models were able to describe accurately the experimental data. The kinetic rates were found to change among the four different WWTPs studied or even in the same plant during different seasons, either suggesting the presence of additional PAO or GAO organisms, or varying microbial activities for the same organisms. Nevertheless, these variations in kinetic rates were largely found to be proportional to the difference in acetate uptake rate, suggesting a viable means of calibrating the metabolic model. The application of the metabolic model to full-scale sludge also revealed that different Accumulibacter clades likely possess different acetate uptake mechanisms, as a correlation was observed between the energetic requirement for acetate transport across the cell membrane with the diversity of Accumulibacter present. Using the model as a predictive tool, it was shown that lower acetate concentrations in the feed as well as longer aerobic retention times favour the dominance of the TCA metabolism over glycolysis, which could explain why the anaerobic TCA pathway seems to be more relevant in full-scale WWTPs than in lab-scale systems. Copyright © 2014 Elsevier Ltd. All
Brenders, A. J.; Pratt, R. G.
2007-01-01
A comprehensive validation of 2-D, frequency-domain, acoustic wave-equation tomography was undertaken in a `blind test', using third-party, realistic, elastic wave-equation data. The synthetic 2-D, wide-angle seismic data were provided prior to a recent workshop on the methods of controlled source seismology; the true model was not revealed to the authors until after the presentation of our waveform tomography results. The original model was specified on a detailed grid with variable P-wave velocity, S-wave velocity, density and viscoelastic Q-factor structure, designed to simulate a section of continental crust 250 km long and 40 km deep. Synthetic vertical and horizontal component data were available for 51 shot locations (spaced every 5 km), recorded at 2779 receivers (spaced every 90 m), evenly spread along the surface of the model. The data contained energy from 0.2 to 15 Hz. Waveform tomography, a combination of traveltime tomography and 2-D waveform inversion of the early arrivals of the seismic waveforms, was used to recover crustal P-velocity structure from the vertical component data, using data from 51 sources, 1390 receivers and frequencies between 0.8 and 7.0 Hz. The waveform tomography result contained apparent structure at wavelength-scale resolution that was not evident on the traveltime tomography result. The predicted (acoustic) waveforms in the final result matched the original elastic data to a high degree of accuracy. During the workshop, the exact model was revealed; over much of the model the waveform tomography results provided a good correspondence with the true model, from large- to intermediate-(wavelength) scales, with a resolution limit on the order of 1 km. A significant, near-surface low-velocity zone, invisible to traveltime methods, was correctly recovered; the results also provided a high-resolution image of the complex structure of the entire crust, and the depth and nature of the crust-mantle transition. Some inaccuracies were
Calibration of aero-structural reduced order models using full-field experimental measurements
Perez, R.; Bartram, G.; Beberniss, T.; Wiebe, R.; Spottswood, S. M.
2017-03-01
The structural response of hypersonic aircraft panels is a multi-disciplinary problem, where the nonlinear structural dynamics, aerodynamics, and heat transfer models are coupled. A clear understanding of the impact of high-speed flow effects on the structural response, and the potential influence of the structure on the local environment, is needed in order to prevent the design of overly-conservative structures, a common problem in past hypersonic programs. The current work investigates these challenges from a structures perspective. To this end, the first part of this investigation looks at the modeling of the response of a rectangular panel to an external heating source (thermo-structural coupling) where the temperature effect on the structure is obtained from forward looking infrared (FLIR) measurements and the displacement via 3D-digital image correlation (DIC). The second part of the study uses data from a previous series of wind-tunnel experiments, performed to investigate the response of a compliant panel to the effects of high-speed flow, to train a pressure surrogate model. In this case, the panel aero-loading is obtained from fast-response pressure sensitive paint (PSP) measurements, both directly and from the pressure surrogate model. The result of this investigation is the use of full-field experimental measurements to update the structural model and train a computational efficient model of the loading environment. The use of reduced order models, informed by these full-field physical measurements, is a significant step toward the development of accurate simulation models of complex structures that are computationally tractable.
Full counting statistics in the self-dual interacting resonant level model.
Carr, Sam T; Bagrets, Dmitry A; Schmitteckert, Peter
2011-11-11
We present a general technique to obtain the zero temperature cumulant generating function of the full counting statistics of charge transfer in interacting impurity models out of equilibrium from time-dependent simulations on a lattice. We demonstrate the technique with application to the self-dual interacting resonant level model, where very good agreement between numerical simulations using the density matrix renormalization group and those obtained analytically from the thermodynamic Bethe ansatz is found. We show from the exact form of counting statistics that the quasiparticles involved in transport carry charge 2e in the low bias regime and e/2 in the high bias regime.
Method of Harmonic Balance in Full-Scale-Model Tests of Electrical Devices
Gorbatenko, N. I.; Lankin, A. M.; Lankin, M. V.
2017-01-01
Methods for determining the weber-ampere characteristics of electrical devices, one of which is based on solution of direct problem of harmonic balance and the other on solution of inverse problem of harmonic balance by the method of full-scale-model tests, are suggested. The mathematical model of the device is constructed using the describing function and simplex optimization methods. The presented results of experimental applications of the method show its efficiency. The advantage of the method is the possibility of application for nondestructive inspection of electrical devices in the processes of their production and operation.
DEFF Research Database (Denmark)
Kiil, Søren
2017-01-01
particle size distribution was simulated. Data from two previous experimental investigations were used for model validation. The first concerns two different yellow organic pigments dispersed in nitrocellulose/ethanol vehicles in a ball mill and the second a red organic pigment dispersed in a solvent-based....... The only adjustable parameter used was an apparent rate constant for the linear agglomerate erosion rate. Model simulations, at selected values of time, for the full agglomerate particle size distribution were in good qualitative agreement with the measured values. A quantitative match of the experimental...
Directory of Open Access Journals (Sweden)
Chun-Nan Chen
2016-08-01
Full Text Available Mainly based on non-equilibrium Green’s function technique in combination with the three-band model, a full atomistic-scale and full quantum method for solving quantum transport problems of a zigzag-edge molybdenum disulfide nanoribbon (zMoSNR structure is proposed here. For transport calculations, the relational expressions of a zMoSNR crystalline solid and its whole device structure are derived in detail and in its integrity. By adopting the complex-band structure method, the boundary treatment of this open boundary system within the non-equilibrium Green’s function framework is so straightforward and quite sophisticated. The transmission function, conductance, and density of states of zMoSNR devices are calculated using the proposed method. The important findings in zMoSNR devices such as conductance quantization, van Hove singularities in the density of states, and contact interaction on channel are presented and explored in detail.
Adjustment and Characterization of an Original Model of Chronic Ischemic Heart Failure in Pig
Directory of Open Access Journals (Sweden)
Laurent Barandon
2010-01-01
Full Text Available We present and characterize an original experimental model to create a chronic ischemic heart failure in pig. Two ameroid constrictors were placed around the LAD and the circumflex artery. Two months after surgery, pigs presented a poor LV function associated with a severe mitral valve insufficiency. Echocardiography analysis showed substantial anomalies in radial and circumferential deformations, both on the anterior and lateral surface of the heart. These anomalies in function were coupled with anomalies of perfusion observed in echocardiography after injection of contrast medium. No demonstration of myocardial infarction was observed with histological analysis. Our findings suggest that we were able to create and to stabilize a chronic ischemic heart failure model in the pig. This model represents a useful tool for the development of new medical or surgical treatment in this field.
Full-Waveform Validation of a 3D Seismic Model for Western US
Maceira, M.; Larmat, C. S.; Ammon, C. J.; Chai, C.; Herrmann, R. B.
2014-12-01
Since the initiation of tomographic studies in the 1970s, geoscientists have advanced the art of inferring 3D variations in the subsurface using collections of geophysical (primarily seismic) observables recorded at or near Earth's surface. Advances have come from improvement and enhancement of the available data and from research on theoretical and computational improvements to tomographic and generalized inverse methods. In the last decade, utilizing dense array datasets, these efforts have led to unprecedented 3D images of the subsurface. Understandably, less effort has been expended on model validation to provide an absolute assessment of model uncertainty. Generally models constructed with different data sets and independent computational codes are assessed with geological reasonability and compared other models to gain confidence. The question of "How good is a particular 3D geophysical model at representing the Earth's true nature?" remains largely unaddressed at a time when 3D Earth models are used for both societal and energy security. In the last few years, opportunities have arisen in earth-structure imaging, including the advent of new methods in computational seismology and statistical sciences. We use the unique and extensive High Performance Computing resources available at Los Alamos National Laboratory to explore approaches to realistic model validation. We present results from a study focused on validating a 3D model for the western United States generated using a joint inversion simultaneously fitting interpolated teleseismic P-wave receiver functions, Rayleigh-wave group-velocity estimates between 7 and 250 s period, and high-wavenumber filtered Bouguer gravity observations. Validation of the obtained model is performed through systematic comparison of observed and predicted seismograms generated using the Spectral Element Method, which is a direct numerical solution for full waveform modeling in 3D models, with accuracy of spectral methods.
Broström, G.; Carrasco, A.; Hole, L. R.; Dick, S.; Janssen, F.; Mattsson, J.; Berger, S.
2011-11-01
Oil spill modeling is considered to be an important part of a decision support system (DeSS) for oil spill combatment and is useful for remedial action in case of accidents, as well as for designing the environmental monitoring system that is frequently set up after major accidents. Many accidents take place in coastal areas, implying that low resolution basin scale ocean models are of limited use for predicting the trajectories of an oil spill. In this study, we target the oil spill in connection with the "Full City" accident on the Norwegian south coast and compare operational simulations from three different oil spill models for the area. The result of the analysis is that all models do a satisfactory job. The "standard" operational model for the area is shown to have severe flaws, but by applying ocean forcing data of higher resolution (1.5 km resolution), the model system shows results that compare well with observations. The study also shows that an ensemble of results from the three different models is useful when predicting/analyzing oil spill in coastal areas.
Raabe, Margaret E; Chaudhari, Ajit M W
2016-05-03
The ability of a biomechanical simulation to produce results that can translate to real-life situations is largely dependent on the physiological accuracy of the musculoskeletal model. There are a limited number of freely-available, full-body models that exist in OpenSim, and those that do exist are very limited in terms of trunk musculature and degrees of freedom in the spine. Properly modeling the motion and musculature of the trunk is necessary to most accurately estimate lower extremity and spinal loading. The objective of this study was to develop and validate a more physiologically accurate OpenSim full-body model. By building upon three previously developed OpenSim models, the full-body lumbar spine (FBLS) model, comprised of 21 segments, 30 degrees-of-freedom, and 324 musculotendon actuators, was developed. The five lumbar vertebrae were modeled as individual bodies, and coupled constraints were implemented to describe the net motion of the spine. The eight major muscle groups of the lumbar spine were modeled (rectus abdominis, external and internal obliques, erector spinae, multifidus, quadratus lumborum, psoas major, and latissimus dorsi), and many of these muscle groups were modeled as multiple fascicles allowing the large muscles to act in multiple directions. The resulting FBLS model׳s trunk muscle geometry, maximal isometric joint moments, and simulated muscle activations compare well to experimental data. The FBLS model will be made freely available (https://simtk.org/home/fullbodylumbar) for others to perform additional analyses and develop simulations investigating full-body dynamics and contributions of the trunk muscles to dynamic tasks.
Li, Tsung-Lung; Lu, Wen-Cai
2015-10-05
In this work, Koopmans' theorem for Kohn-Sham density functional theory (KS-DFT) is applied to the photoemission spectra (PES) modeling over the entire valence-band. To examine the validity of this application, a PES modeling scheme is developed to facilitate a full valence-band comparison of theoretical PES spectra with experiments. The PES model incorporates the variations of electron ionization cross-sections over atomic orbitals and a linear dispersion of spectral broadening widths. KS-DFT simulations of pristine rubrene (5,6,11,12-tetraphenyltetracene) and potassium-rubrene complex are performed, and the simulation results are used as the input to the PES models. Two conclusions are reached. First, decompositions of the theoretical total spectra show that the dissociated electron of the potassium mainly remains on the backbone and has little effect on the electronic structures of phenyl side groups. This and other electronic-structure results deduced from the spectral decompositions have been qualitatively obtained with the anionic approximation to potassium-rubrene complexes. The qualitative validity of the anionic approximation is thus verified. Second, comparison of the theoretical PES with the experiments shows that the full-scale simulations combined with the PES modeling methods greatly enhance the agreement on spectral shapes over the anionic approximation. This agreement of the theoretical PES spectra with the experiments over the full valence-band can be regarded, to some extent, as a collective validation of the application of Koopmans' theorem for KS-DFT to valence-band PES, at least, for this hydrocarbon and its alkali-adsorbed complex. Copyright © 2015 Elsevier B.V. All rights reserved.
A selection model for accounting for publication bias in a full network meta-analysis.
Mavridis, Dimitris; Welton, Nicky J; Sutton, Alex; Salanti, Georgia
2014-12-30
Copas and Shi suggested a selection model to explore the potential impact of publication bias via sensitivity analysis based on assumptions for the probability of publication of trials conditional on the precision of their results. Chootrakool et al. extended this model to three-arm trials but did not fully account for the implications of the consistency assumption, and their model is difficult to generalize for complex network structures with more than three treatments. Fitting these selection models within a frequentist setting requires maximization of a complex likelihood function, and identification problems are common. We have previously presented a Bayesian implementation of the selection model when multiple treatments are compared with a common reference treatment. We now present a general model suitable for complex, full network meta-analysis that accounts for consistency when adjusting results for publication bias. We developed a design-by-treatment selection model to describe the mechanism by which studies with different designs (sets of treatments compared in a trial) and precision may be selected for publication. We fit the model in a Bayesian setting because it avoids the numerical problems encountered in the frequentist setting, it is generalizable with respect to the number of treatments and study arms, and it provides a flexible framework for sensitivity analysis using external knowledge. Our model accounts for the additional uncertainty arising from publication bias more successfully compared to the standard Copas model or its previous extensions. We illustrate the methodology using a published triangular network for the failure of vascular graft or arterial patency.
Model selection for quantitative trait loci mapping in a full-sib family
Directory of Open Access Journals (Sweden)
Chunfa Tong
2012-01-01
Full Text Available Statistical methods for mapping quantitative trait loci (QTLs in full-sib forest trees, in which the number of alleles and linkage phase can vary from locus to locus, are still not well established. Previous studies assumed that the QTL segregation pattern was fixed throughout the genome in a full-sib family, despite the fact that this pattern can vary among regions of the genome. In this paper, we propose a method for selecting the appropriate model for QTL mapping based on the segregation of different types of markers and QTLs in a full-sib family. The QTL segregation patterns were classified into three types: test cross (1:1 segregation, F2 cross (1:2:1 segregation and full cross (1:1:1:1 segregation. Akaike's information criterion (AIC, the Bayesian information criterion (BIC and the Laplace-empirical criterion (LEC were used to select the most likely QTL segregation pattern. Simulations were used to evaluate the power of these criteria and the precision of parameter estimates. A Windows-based software was developed to run the selected QTL mapping method. A real example is presented to illustrate QTL mapping in forest trees based on an integrated linkage map with various segregation markers. The implications of this method for accurate QTL mapping in outbred species are discussed.
Integrated ray tracing simulation of spectral bio-signatures from full 3D earth model
Ryu, Dongok; Seong, Sehyun; Lee, Jae-Min; Hong, Jinsuk; Jeong, Soomin; Jeong, Yukyeong; Kim, Sug-Whan
2009-08-01
Accurate identification and understanding of spectral bio-signatures from possible extra terrestrial planets have received an ever increasing attention from both astronomy and space science communities in recent years. In pursuance of this subject, one of the most important scientific breakthroughs would be to obtain the detailed understanding on spectral biosignatures of the Earth, as it serves as a reference datum for accurate interpretation of collapsed (in temporal and spatial domains) information from the spectral measurement using TPF instruments. We report a new Integrated Ray Tracing (IRT) model capable of computing various spectral bio-signatures as they are observed from the Earth surface. The model includes the Sun, the full 3-D Earth, and an optical instrument, all combined into single ray tracing environment in real scale. In particular, the full 3-D Earth surface is constructed from high resolution coastal line data and defined with realistic reflectance and BSDF characteristics depending on wavelength, vegetation types and their distributions. We first examined the model validity by confirming the imaging and radiometric performance of the AmonRa visible channel camera, simulating the Earth observation from the L1 halo orbit. We then computed disk averaged spectra, light curves and NDVI indexes, leading to the construction of the observed disk averaged spectra at the AmonRa instrument detector plane. The model, computational procedure and the simulation results are presented. The future plan for the detailed spectral signature simulation runs for various input conditions including seasonal vegetation changes and variable cloud covers is discussed.
The Single Period Inventory Model: Origins, Solutions, Variations, and Applications.
1977-09-01
34News boy problem ", [1] "Newspaper boy problem ", [2] "Newspaper vendor problem ", [3] " Newsvendor problem ", [4] "Christmas tree problem ", [5] and so...miXr) % ^The classic newspaper boy or single period inventory problem is reviewed, and its origins and development during the past 30 years are...traced. The review reveals several variations for the classic problem , both in cost structure and in the decision principles involved. The critical
Hongyang, Yu; Zhengang, Lu; Xi, Yang
2017-05-01
Modular Multilevel Converter is more and more widely used in high voltage DC transmission system and high power motor drive system. It is a major topological structure for high power AC-DC converter. Due to the large module number, the complex control algorithm, and the high power user’s back ground, the MMC model used for simulation should be as accurate as possible to simulate the details of how MMC works for the dynamic testing of the MMC controller. But so far, there is no sample simulation MMC model which can simulate the switching dynamic process. In this paper, one curve embedded full-bridge MMC modeling method with detailed representation of IGBT characteristics is proposed. This method is based on the switching curve referring and sample circuit calculation, and it is sample for implementation. Based on the simulation comparison test under Matlab/Simulink, the proposed method is proved to be correct.
The mode trapping properties of full DA white dwarf evolutionary models
Corsico, A H; Benvenuto, O G; Serenelli, A M
2002-01-01
An adiabatic, non-radial pulsation study of a 0.563 M_sun DA white dwarf model is presented on the basis of new evolutionary calculations performed in a self-consistent way with the predictions of time dependent element diffusion, nuclear burning and the history of the white dwarf progenitor. Emphasis is placed on the role played by the internal chemical stratification of these new models in the behaviour of the eigenmodes, and the expectations for the full g-spectrum of periods. The implications for the mode trapping properties are discussed at length. In this regard, we find that, for high periods, the viability of mode trapping as a mode selection mechanism is markedly weaker for our models, as compared with the situation in which the hydrogen-helium transition region is treated assuming equilibrium diffusion in the trace element approximation.
Business models for full service energy renovation of single-family houses in Nordic countries
DEFF Research Database (Denmark)
Mahapatra, Krushna; Gustavsson, Leif; Haavik, Trond
2013-01-01
markets are dominated by handicraft-based individual solutions. In this paper we have analyzed the opportunities for implementation of one-stop-shop business models where an overall contractor offers full-service renovation packages including consulting, independent energy audit, renovation work, follow-up...... (independent quality control and commissioning) and financing. A comparative assessment of emerging business models in the Nordic countries shows that different types of actors can provide such a service. Financing is included in some models. There are differences in how customers are contacted, while...... the similarities are on how the service is provided. Even though there is strong business potential for one-stop-shop energy renovation concept, still it has been somewhat difficult to start or run such a business. Various options to overcome the hindrances to promote energy efficient renovation of detached houses...
Model of Optimal Cargo Transport Structure by Full Container Ship on Predefined Sailing Route
Directory of Open Access Journals (Sweden)
Serđo Kos
2004-01-01
Full Text Available This paper presents the mathematical model for solving theproblem of defining optimal cargo transport structure, occurringwhen, on a predefined sailing route, adequate number ofcontainers of various types, masses and sizes, possibly includingRO!RO cargo, is to be selected, i.e., a "container lot" is to beestablished in loading ports with the aim of gaining maximumship profit and, at the same time, of exploiting useful load andtransport capacity of container ship as much as possible. Theimplementation of the proposed model enables considerableincrease in the efficiency of container ship operations. Themodel was tested using a numerical example with real data.The applied post-optimal analysis examines the influence ofchange in some values of the mathematical model on the resultingoptimal program.
Full field reservoir modeling of shale assets using advanced data-driven analytics
Directory of Open Access Journals (Sweden)
Soodabeh Esmaili
2016-01-01
Full Text Available Hydrocarbon production from shale has attracted much attention in the recent years. When applied to this prolific and hydrocarbon rich resource plays, our understanding of the complexities of the flow mechanism (sorption process and flow behavior in complex fracture systems - induced or natural leaves much to be desired. In this paper, we present and discuss a novel approach to modeling, history matching of hydrocarbon production from a Marcellus shale asset in southwestern Pennsylvania using advanced data mining, pattern recognition and machine learning technologies. In this new approach instead of imposing our understanding of the flow mechanism, the impact of multi-stage hydraulic fractures, and the production process on the reservoir model, we allow the production history, well log, completion and hydraulic fracturing data to guide our model and determine its behavior. The uniqueness of this technology is that it incorporates the so-called “hard data” directly into the reservoir model, so that the model can be used to optimize the hydraulic fracture process. The “hard data” refers to field measurements during the hydraulic fracturing process such as fluid and proppant type and amount, injection pressure and rate as well as proppant concentration. This novel approach contrasts with the current industry focus on the use of “soft data” (non-measured, interpretive data such as frac length, width, height and conductivity in the reservoir models. The study focuses on a Marcellus shale asset that includes 135 wells with multiple pads, different landing targets, well length and reservoir properties. The full field history matching process was successfully completed using this data driven approach thus capturing the production behavior with acceptable accuracy for individual wells and for the entire asset.
2.5-D forward and inverse modelling of full-waveform elastic seismic survey
Xiong, J. L.; Lin, Y.; Abubakar, A.; Habashy, T. M.
2013-05-01
We present a two-and-half-dimensional (2.5-D) forward and inversion algorithm for the interpretation of surface seismic elastic full-waveform data. The 2-D modelling approach for elastic waves might not be sufficiently accurate because of its line-source assumption. On the other hand, a full 3-D modelling of elastic waves is still computationally very expensive for seismic exploration applications. By employing the 2.5-D modelling approach, we assume that the elastic medium is 2-D while the source is a 3-D point source. We solve the 2.5-D problem by first transforming the elastic wave equation in the spatial domain into the wavenumber domain. Then, for each wavenumber we solve a 2-D problem using the finite difference method with staggered grids. After that an inverse wavenumber transform is performed to compute the 3-D field distribution. To handle the inverse transform, we develop an efficient numerical integration scheme by subdividing the integration domain and applying different integration rules to each subinterval. We show that this approach works well for surface seismic applications. The 2.5-D approach offers a more realistic modelling of the elastic wave data, hence it produces more accurate inversion results than the 2-D inversion approach. Finally, we validate this approach by using a numerical test. In this test we used our 2.5-D full-waveform inversion algorithm to invert the synthetic data generated by a 3-D finite-difference time-domain simulation.
Development of a Full Ice-cream Cone Model for Halo Coronal Mass Ejections
Na, Hyeonock; Moon, Y.-J.; Lee, Harim
2017-04-01
It is essential to determine three-dimensional parameters (e.g., radial speed, angular width, and source location) of coronal mass ejections (CMEs) for the space weather forecast. In this study, we investigate which cone type represents a halo CME morphology using 29 CMEs (12 Solar and Heliospheric Observatory (SOHO)/Large Angle and Spectrometric Coronagraph (LASCO) halo CMEs and 17 Solar Terrestrial Relations Observatory (STEREO)/Sun-Earth Connection Coronal and Heliospheric Investigation COR2 halo CMEs) from 2010 December to 2011 June. These CMEs are identified as halo CMEs by one spacecraft (SOHO or one of STEREO A and B) and limb ones by the other spacecraft (One of STEREO A and B or SOHO). From cone shape parameters of these CMEs, such as their front curvature, we find that the CME observational structures are much closer to a full ice-cream cone type than a shallow ice-cream cone type. Thus, we develop a full ice-cream cone model based on a new methodology that the full ice-cream cone consists of many flat cones with different heights and angular widths to estimate the three-dimensional parameters of the halo CMEs. This model is constructed by carrying out the following steps: (1) construct a cone for a given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, and (4) minimize the difference between the estimated projection speeds with the observed ones. By applying this model to 12 SOHO/LASCO halo CMEs, we find that 3D parameters from our method are similar to those from other stereoscopic methods (i.e., a triangulation method and a Graduated Cylindrical Shell model).
The research and practice based on the full-time visitation model in clinical medical education
Directory of Open Access Journals (Sweden)
Hong Zhang
2015-01-01
Full Text Available Most of the higher medical colleges and universities teaching hospital carry certain clinical teaching tasks, but the traditional teaching pattern of "two stage", including the early stage of the theory of teaching, the late arrangement of clinical practice, had some drawbacks such as practice time is too concentrated and the chasm between students' theory and practice. It is suggested that students contact clinical diagnosis and treatment earlier, visit more patients and increase the ratio of visitation and course. But as more and more students flood into university, clinical visitation has turned into a difficulty to improve students’ ability. To resolve this problem, we have made some efficient practice and exploration in Rizhao City People's Hospital from September 2005 to July 2014. The students were divided into full-time visitation model group and “two stage” pattern group randomly. The single factors are of great difference between the two groups. The full-time visitation model in clinical medical education builds a new mode of practice of clinical practice teaching in the medical stuents' concept of doctor-patient communication, humanistic care to patients, basic theoretical knowledge, clinical practice skills and graduate admission rate increased significantly. Continuous improvement of OSCE exam is needed to make evaluation more scientific, objective and fair.
Superresolution Full-polarimetric Imaging for Radio Interferometry with Sparse Modeling
Akiyama, Kazunori; Ikeda, Shiro; Pleau, Mollie; Fish, Vincent L.; Tazaki, Fumie; Kuramochi, Kazuki; Broderick, Avery E.; Dexter, Jason; Mościbrodzka, Monika; Gowanlock, Michael; Honma, Mareki; Doeleman, Sheperd S.
2017-04-01
We propose a new technique for radio interferometry to obtain superresolution full-polarization images in all four Stokes parameters using sparse modeling. The proposed technique reconstructs the image in each Stokes parameter from the corresponding full-complex Stokes visibilities by utilizing two regularization functions: the ℓ 1 norm and the total variation (TV) of the brightness distribution. As an application of this technique, we present simulated linear polarization observations of two physically motivated models of M87 with the Event Horizon Telescope. We confirm that ℓ 1+TV regularization can achieve an optimal resolution of ˜25%-30% of the diffraction limit λ /{D}\\max , which is the nominal spatial resolution of a radio interferometer for both the total intensity (i.e., Stokes I) and linear polarizations (i.e., Stokes Q and U). This optimal resolution is better than that obtained from the widely used Cotton-Schwab CLEAN algorithm or from using ℓ 1 or TV regularizations alone. Furthermore, we find that ℓ 1+TV regularization can achieve much better image fidelity in linear polarization than other techniques over a wide range of spatial scales, not only in the superresolution regime, but also on scales larger than the diffraction limit. Our results clearly demonstrate that sparse reconstruction is a useful choice for high-fidelity full-polarimetric interferometric imaging.
Full modelling of the MOSAIC animal PET system based on the GATE Monte Carlo simulation code
Merheb, C.; Petegnief, Y.; Talbot, J. N.
2007-02-01
Positron emission tomography (PET) systems dedicated to animal imaging are now widely used for biological studies. The scanner performance strongly depends on the design and the characteristics of the system. Many parameters must be optimized like the dimensions and type of crystals, geometry and field-of-view (FOV), sampling, electronics, lightguide, shielding, etc. Monte Carlo modelling is a powerful tool to study the effect of each of these parameters on the basis of realistic simulated data. Performance assessment in terms of spatial resolution, count rates, scatter fraction and sensitivity is an important prerequisite before the model can be used instead of real data for a reliable description of the system response function or for optimization of reconstruction algorithms. The aim of this study is to model the performance of the Philips Mosaic™ animal PET system using a comprehensive PET simulation code in order to understand and describe the origin of important factors that influence image quality. We use GATE, a Monte Carlo simulation toolkit for a realistic description of the ring PET model, the detectors, shielding, cap, electronic processing and dead times. We incorporate new features to adjust signal processing to the Anger logic underlying the Mosaic™ system. Special attention was paid to dead time and energy spectra descriptions. Sorting of simulated events in a list mode format similar to the system outputs was developed to compare experimental and simulated sensitivity and scatter fractions for different energy thresholds using various models of phantoms describing rat and mouse geometries. Count rates were compared for both cylindrical homogeneous phantoms. Simulated spatial resolution was fitted to experimental data for 18F point sources at different locations within the FOV with an analytical blurring function for electronic processing effects. Simulated and measured sensitivities differed by less than 3%, while scatter fractions agreed
Directory of Open Access Journals (Sweden)
Anneke Brümmer
2010-05-01
Full Text Available Eukaryotic genomes are duplicated from multiple replication origins exactly once per cell cycle. In Saccharomyces cerevisiae, a complex molecular network has been identified that governs the assembly of the replication machinery. Here we develop a mathematical model that links the dynamics of this network to its performance in terms of rate and coherence of origin activation events, number of activated origins, the resulting distribution of replicon sizes and robustness against DNA rereplication. To parameterize the model, we use measured protein expression data and systematically generate kinetic parameter sets by optimizing the coherence of origin firing. While randomly parameterized networks yield unrealistically slow kinetics of replication initiation, networks with optimized parameters account for the experimentally observed distribution of origin firing times. Efficient inhibition of DNA rereplication emerges as a constraint that limits the rate at which replication can be initiated. In addition to the separation between origin licensing and firing, a time delay between the activation of S phase cyclin-dependent kinase (S-Cdk and the initiation of DNA replication is required for preventing rereplication. Our analysis suggests that distributive multisite phosphorylation of the S-Cdk targets Sld2 and Sld3 can generate both a robust time delay and contribute to switch-like, coherent activation of replication origins. The proposed catalytic function of the complex formed by Dpb11, Sld3 and Sld2 strongly enhances coherence and robustness of origin firing. The model rationalizes how experimentally observed inefficient replication from fewer origins is caused by premature activation of S-Cdk, while premature activity of the S-Cdk targets Sld2 and Sld3 results in DNA rereplication. Thus the model demonstrates how kinetic deregulation of the molecular network governing DNA replication may result in genomic instability.
A combined computational and structural model of the full-length human prolactin receptor
DEFF Research Database (Denmark)
Bugge, Katrine Østergaard; Papaleo, Elena; Haxholm, Gitte Wolfsberg;
2016-01-01
The prolactin receptor is an archetype member of the class I cytokine receptor family, comprising receptors with fundamental functions in biology as well as key drug targets. Structurally, each of these receptors represent an intriguing diversity, providing an exceptionally challenging target...... for structural biology. Here, we access the molecular architecture of the monomeric human prolactin receptor by combining experimental and computational efforts. We solve the NMR structure of its transmembrane domain in micelles and collect structural data on overlapping fragments of the receptor with small......-angle X-ray scattering, native mass spectrometry and NMR spectroscopy. Along with previously published data, these are integrated by molecular modelling to generate a full receptor structure. The result provides the first full view of a class I cytokine receptor, exemplifying the architecture of more than...
A combined computational and structural model of the full-length human prolactin receptor
Bugge, Katrine; Papaleo, Elena; Haxholm, Gitte W.; Hopper, Jonathan T. S.; Robinson, Carol V.; Olsen, Johan G.; Lindorff-Larsen, Kresten; Kragelund, Birthe B.
2016-05-01
The prolactin receptor is an archetype member of the class I cytokine receptor family, comprising receptors with fundamental functions in biology as well as key drug targets. Structurally, each of these receptors represent an intriguing diversity, providing an exceptionally challenging target for structural biology. Here, we access the molecular architecture of the monomeric human prolactin receptor by combining experimental and computational efforts. We solve the NMR structure of its transmembrane domain in micelles and collect structural data on overlapping fragments of the receptor with small-angle X-ray scattering, native mass spectrometry and NMR spectroscopy. Along with previously published data, these are integrated by molecular modelling to generate a full receptor structure. The result provides the first full view of a class I cytokine receptor, exemplifying the architecture of more than 40 different receptor chains, and reveals that the extracellular domain is merely the tip of a molecular iceberg.
Schminkey, Donna L; von Oertzen, Timo; Bullock, Linda
2016-08-01
With increasing access to population-based data and electronic health records for secondary analysis, missing data are common. In the social and behavioral sciences, missing data frequently are handled with multiple imputation methods or full information maximum likelihood (FIML) techniques, but healthcare researchers have not embraced these methodologies to the same extent and more often use either traditional imputation techniques or complete case analysis, which can compromise power and introduce unintended bias. This article is a review of options for handling missing data, concluding with a case study demonstrating the utility of multilevel structural equation modeling using full information maximum likelihood (MSEM with FIML) to handle large amounts of missing data. MSEM with FIML is a parsimonious and hypothesis-driven strategy to cope with large amounts of missing data without compromising power or introducing bias. This technique is relevant for nurse researchers faced with ever-increasing amounts of electronic data and decreasing research budgets. © 2016 Wiley Periodicals, Inc.
Inverting reflections using full-waveform inversion with inaccurate starting models
AlTheyab, Abdullah
2015-08-19
We present a method for inverting seismic reflections using full-waveform inversion (FWI) with inaccurate starting models. For a layered medium, near-offset reflections (with zero angle of incidence) are unlikely to be cycle-skipped regardless of the low-wavenumber velocity error in the initial models. Therefore, we use them as a starting point for FWI, and the subsurface velocity model is then updated during the FWI iterations using reflection wavepaths from varying offsets that are not cycle-skipped. To enhance low-wavenumber updates and accelerate the convergence, we take several passes through the non-linear Gauss-Seidel iterations, where we invert traces from a narrow range of near offsets and finally end at the far offsets. Every pass is followed by applying smoothing to the cumulative slowness update. The smoothing is strong at the early stages and relaxed at later iterations to allow for a gradual reconstruction of the subsurface model in a multiscale manner. Applications to synthetic and field data, starting from inaccurate models, show significant low-wavenumber updates and flattening of common-image gathers after many iterations.
Computer simulation of active suspension based on the full-vehicle model
Institute of Scientific and Technical Information of China (English)
李军; CHEN; Shanguo
2002-01-01
The current method to solve the problem of active suspension control for a vehicle is often dealt with a quarter-car or half-car model.But it is not enough to use this kind of model for practical applications.In this paper,based on considering the influence of factors such as,seat and passengers a MDOF(multi-degree-of-freedom)model describing the vehicle motion is set up.The MODF model,which is 8DOF of four independent suspensions and four wheel tracks,is more applicable by comparison of its analysis result with some conventional vehicle models.Therefore,it is more suitable to use the 8DOF full-car model than a conventional 4DOF half-car model in the active control design for car vibration.Based on the derived 8DOF odel,a controller is designed by using LQ(linear quadratic)control theory,and the appropriate control scheme is selected by testing various performance indexes.Computer simulation 8is carried out for a passenger car running on a road with step disturbance and random road disturbance expressed by Power Spectral Density(PSD).Vibrations corresponding to ride comfort are derived under the foregoing road disturbances.The response results for uncontrolled and controlled system are compared.The response of vehicle vibration is greatly suppressed and quickly damped.which testifies the effect of the active suspenson.The results achieved for various controllers are compared to invesigate the influence of different control schemes on the control effect.
Lane-changing behavior and its effect on energy dissipation using full velocity difference model
Wang, Jian; Ding, Jian-Xun; Shi, Qin; Kühne, Reinhart D.
2016-07-01
In real urban traffic, roadways are usually multilane with lane-specific velocity limits. Most previous researches are derived from single-lane car-following theory which in the past years has been extensively investigated and applied. In this paper, we extend the continuous single-lane car-following model (full velocity difference model) to simulate the three-lane-changing behavior on an urban roadway which consists of three lanes. To meet incentive and security requirements, a comprehensive lane-changing rule set is constructed, taking safety distance and velocity difference into consideration and setting lane-specific speed restriction for each lane. We also investigate the effect of lane-changing behavior on distribution of cars, velocity, headway, fundamental diagram of traffic and energy dissipation. Simulation results have demonstrated asymmetric lane-changing “attraction” on changeable lane-specific speed-limited roadway, which leads to dramatically increasing energy dissipation.
The Children's Aid Society community schools: a full-service partnership model.
Quinn, Jane
2005-01-01
In 1989, the Children's Aid Society (CAS) created an unprecedented partnership with the New York City Board of Education by developing a comprehensive response to the pressing needs of children and families in the northern Manhattan neighborhood of Washington Heights. After three years of careful planning, CAS and the New York City public schools opened the first community school at Intermediate School 218, offering a full array of supports, services, and learning opportunities. Adding, on average, one partnership school per year and remaining very flexible in adapting its model to the individual needs of each community, CAS now has thirteen community schools around New York City. The model's flexibility is seen also in the success of its national and international adaptation-an intentional part of CAS's work.
Putting in operation a full-scale ultracold-neutron source model with superfluid helium
Serebrov, A. P.; Lyamkin, V. A.; Prudnikov, D. V.; Keshishev, K. O.; Boldarev, S. T.; Vasil'ev, A. V.
2017-02-01
A project of the source of ultracold neutrons for the WWR-M reactor based on superfluid helium for ultracold-neutron production has been developed. The full-scale source model, including all required cryogenic and vacuum equipment, the cryostat, and the ultracold-neutron source model has been created. The superfluid helium temperature T = 1.08 K without a heat load and T = 1.371 K with a heat load on the simulator of P = 60 W has been achieved in experiments at a technological complex of the ultracold-neutron source. The result proves the feasibility of implementing the ultracold-neutron source at the WWR-M reactor and the possibility of applying superfluid helium in nuclear engineering.
Research for full-term forecasting model of production rate with multiple life cycle
Wende, Yan; Yingzhong, Yuan; Jun, Liu; Zhilin, Qi; Jiqiang, Li; Qianhua, Xiao
2017-04-01
Based on generalized production forecasting model, in the case of oil production with multiple production peak value and multiple life cycle, a multi-peak forecasting model is proposed, which can describe full course of rise, growth, maturity and decline for every life cycle. Linear trial-and-error method, binary regression method and ternary regression method are used to resolve the parameters of production forecasting model. The results indicate that parameters in linear trial-and-error method are not resolved simultaneously and the solutions are usually not the best matching. Parameters in multi-variant regression method are resolved simultaneously with the best correlation factor, and the solution is more accurate than linear trial-and-error method. Growth factor including cumulative production rate term and exponential function term of time are considered simultaneously in ternary regression method, and the solution is more accurate than binary regression method. For actual example with three-peak production, ternary regression method are used to resolve the parameters of multi-peak production forecasting model, and matching accuracy is greatly improved.
Switching the Liverpool Telescope from a full-service operating model to self-service
Smith, R. J.; Clay, Neil R.; Fraser, Stephen N.; Marchant, J. M.; Moss, C. M.; Steele, I. A.
2010-07-01
The Liverpool Telescope has undergone a major revision of operations model, improving the facility's flexibility and rapid response to targets of opportunity. We switched from a "full service" model where observers submitted requests to the Support Astronomer for checking and uploading into the scheduler database to a direct access model where observers personally load sequences directly into the database at any time, including during the night. A new data model describing the observing specifications has been developed over two years for the back-end operations infrastructure and has been invisible to users until early 2010 when the new graphical user interface was deployed to all observers. The development project has been a success, defined as providing new flexible operating modes to users without incurring any downtime at the change over or interruption to the ongoing monitoring projects in which the observatory specializes. Devolving responsibility for data entry to users does not necessarily simplify the role of observatory staff. Ceding that absolute hands-on control by experienced staff complicates the support task because staff no longer have advance personal knowledge of everything the telescope is doing. In certain cases software utilities and controls can be developed to simplify tasks for both observers and operations staff.
Human factors evaluation of the HL-20 full-scale model
Willshire, Kelli F.; Simonsen, Lisa C.; Willshire, William L., Jr.
1993-01-01
The human factors testing of the HL-20 personnel launch system full-scale model was conducted in both the vertical and horizontal positions at NASA Langley Research Center. Three main areas of testing were considered: an anthropometric fit evaluation, the ingress and egress of a 10-person crew, and pilot viewing. The subjects, ranging from the 5th to 95th percentile size, had sufficient clearance in the model, with the exception of the last two rows of seats and the cockpit area. Adjustable seat heights and/or placement of the seats farther forward would provide more headroom. In the horizontal position, the model's seat placement and aisle width allowed a quick and orderly 10-person egress for the no-keel (a structural support running the length on the aisle), 6-in.-high keel, and 12-in.-high keel conditions. Egress times were less than 20 s. For the vertical position, the model's long cylindrical shape with the ladder in the ceiling allowed a quick and orderly egress with average times less than 30 s. Ingress and egress procedures were demonstrated using Shuttle partial-pressure suits. The reduced mobility experienced while wearing the suits did increase egress times, although they still remained acceptable. The window arrangement for pilot viewing was found to be reasonably acceptable, although slight modifications, such as an increased downward view, is desirable.
High-resolution global tomography: A full-wave technique for forward and inverse modeling
Nissen-Meyer, Tarje; Sigloch, Karin; Fournier, Alexandre
2010-05-01
In recent years, seismology has greatly benefitted from significant progress in digital data collection and processing, accurate numerical methods for wave propagation, and high-performance computing to explore crucial scales of interest in both data and model spaces. We will present a full-wave technique to address the seismic forward and inverse problem at the global scale, with a specific focus on diffracted waves in the lowermost mantle: Our 2D spectral-element method tackles 3D wave propagation through spherically symmetric background models down to seismic frequencies of 1 Hz and delivers the wavefields necessary to construct sensitivity kernels. This specific approach distinguishes itself from the adjoint method in that it requires no knowledge about data structure or observables at the time of forward modeling by means of storing entire reference space-time wavefields. To obtain a direct view of the interconnection between surface displacements and earth structure, we examine the time-dependent sensitivity of the seismic signal to 3D model perturbations. Being highly sensitive to such parameters as epicentral distance, earthquake radiation pattern, depth, frequency, receiver components and time windows, this effort suggests criteria for data selection to optimally illuminate a specific region within the earth. As shown with core-diffracted P-waves, we measure and model our observables (e.g. traveltimes, amplitudes) in multiple-frequency passbands, thereby increasing robustness of the inverse problem and path coverage. This allows us to selectively draw only upon frequency bands with high signal-to-noise ratio. We discuss the selection and usability of data for such a Pdiff tomographic setting, coverage maps and target regions. We also touch upon the validity of a 1D reference model and quantify the applicability range of the first-order Born approximation.
Full field reservoir modeling of shale assets using advanced data-driven analytics
Institute of Scientific and Technical Information of China (English)
Soodabeh Esmaili; Shahab D. Mohaghegh
2016-01-01
Hydrocarbon production from shale has attracted much attention in the recent years. When applied to this prolific and hydrocarbon rich resource plays, our understanding of the complexities of the flow mechanism (sorption process and flow behavior in complex fracture systems-induced or natural) leaves much to be desired. In this paper, we present and discuss a novel approach to modeling, history matching of hydrocarbon production from a Marcellus shale asset in southwestern Pennsylvania using advanced data mining, pattern recognition and machine learning technologies. In this new approach instead of imposing our understanding of the flow mechanism, the impact of multi-stage hydraulic fractures, and the production process on the reservoir model, we allow the production history, well log, completion and hydraulic fracturing data to guide our model and determine its behavior. The uniqueness of this tech-nology is that it incorporates the so-called “hard data” directly into the reservoir model, so that the model can be used to optimize the hydraulic fracture process. The “hard data” refers to field measure-ments during the hydraulic fracturing process such as fluid and proppant type and amount, injection pressure and rate as well as proppant concentration. This novel approach contrasts with the current industry focus on the use of “soft data” (non-measured, interpretive data such as frac length, width, height and conductivity) in the reservoir models. The study focuses on a Marcellus shale asset that in-cludes 135 wells with multiple pads, different landing targets, well length and reservoir properties. The full field history matching process was successfully completed using this data driven approach thus capturing the production behavior with acceptable accuracy for individual wells and for the entire asset.
The expanded triangular Kitaev–Heisenberg model in the full parameter space
Energy Technology Data Exchange (ETDEWEB)
Yao, Xiaoyan, E-mail: yaoxiaoyan@gmail.com
2014-06-13
The classical Kitaev–Heisenberg model on the triangular lattice is investigated by simulation in its full parameter space together with the next-nearest neighboring Heisenberg interaction or the single-ion anisotropy. The variation of the system is demonstrated directly by the joint density of states (DOS) depending on energy and magnetization obtained from Wang–Landau algorithm. The Metropolis Monte Carlo simulation and the zero-temperature Glauber dynamics are performed to show the internal energy, the correlation functions and spin configurations at zero temperature. It is revealed that two types of DOS (U and inverse U) divide the whole parameter range into two main parts with antiferromagnetic and ferromagnetic features respectively. In the parameter range of U type DOS, the mixed frustration from the triangular geometry and the Kitaev interaction produces rich phases, which are influenced in different ways by the next-nearest neighboring Heisenberg interaction and the single-ion anisotropy. - Highlights: • The expanded triangular Kitaev–Heisenberg model is investigated by simulation. • The density of states is shown in the full parameter space. • Rich low-temperature phases are induced by the mixed frustration. • The next nearest-neighboring Heisenberg interaction influences the phases. • The single-ion anisotropy modifies the shape of the density of states.
Manufactured analytical solutions for isothermal full-Stokes ice sheet models
Directory of Open Access Journals (Sweden)
A. Sargent
2010-04-01
Full Text Available We present the detailed construction of an exact solution to time-dependent and steady-state isothermal full-Stokes ice sheet problems. The solutions are constructed for two-dimensional flowline and three-dimensional full-Stokes ice sheet models with variable viscosity. The construction is done by choosing for the specified ice surface and bed a velocity distribution that satisfies both mass conservation and the kinematic boundary conditions. Then a compensatory stress term in the conservation of momentum equations and their boundary conditions is calculated to make the chosen velocity distributions as well as the chosen pressure field into exact solutions. By substituting different ice surface and bed geometry formulas into the derived solution formulas, analytical solutions for different geometries can be constructed.
The boundary conditions can be specified as essential Dirichlet conditions or as periodic boundary conditions. By changing a parameter value, the analytical solutions allow investigation of algorithms for a different range of aspect ratios as well as for different, frozen or sliding, basal conditions. The analytical solutions can also be used to estimate the numerical error of the method in the case when the effects of the boundary conditions are eliminated, that is, when the exact solution values are specified as inflow and outflow boundary conditions.
Manufactured analytical solutions for isothermal full-Stokes ice sheet models
Directory of Open Access Journals (Sweden)
A. Sargent
2010-08-01
Full Text Available We present the detailed construction of a manufactured analytical solution to time-dependent and steady-state isothermal full-Stokes ice sheet problems. The solutions are constructed for two-dimensional flowline and three-dimensional full-Stokes ice sheet models with variable viscosity. The construction is done by choosing for the specified ice surface and bed a velocity distribution that satisfies both mass conservation and the kinematic boundary conditions. Then a compensatory stress term in the conservation of momentum equations and their boundary conditions is calculated to make the chosen velocity distributions as well as the chosen pressure field into exact solutions. By substituting different ice surface and bed geometry formulas into the derived solution formulas, analytical solutions for different geometries can be constructed.
The boundary conditions can be specified as essential Dirichlet conditions or as periodic boundary conditions. By changing a parameter value, the analytical solutions allow investigation of algorithms for a different range of aspect ratios as well as for different, frozen or sliding, basal conditions. The analytical solutions can also be used to estimate the numerical error of the method in the case when the effects of the boundary conditions are eliminated, that is, when the exact solution values are specified as inflow and outflow boundary conditions.
Energy Technology Data Exchange (ETDEWEB)
Watanabe, T.; Sassa, K. [Kyoto University, Kyoto (Japan); Uesaka, S. [Kyoto University, Kyoto (Japan). Faculty of Engineering
1996-10-01
The effect of initial models on full-wave inversion (FWI) analysis based on acoustic wave-equation was studied for elastic wave tomography of underground structures. At present, travel time inversion using initial motion travel time is generally used, and inverse analysis is conducted using the concept `ray,` assuming very high wave frequency. Although this method can derive stable solutions relatively unaffected by initial model, it uses only the data of initial motion travel time. FWI calculates theoretical waveform at each receiver using all of observed waveforms as data by wave equation modeling where 2-D underground structure is calculated by difference calculus under the assumption that wave propagation is described by wave equation of P wave. Although it is a weak point that FWI is easily affected by noises in an initial model and data, it is featured by high resolution of solutions. This method offers very excellent convergence as a proper initial model is used, resulting in sufficient performance, however, it is strongly affected by initial model. 2 refs., 7 figs., 1 tab.
Full Bayesian hierarchical light curve modeling of core-collapse supernova populations
Sanders, Nathan; Betancourt, Michael; Soderberg, Alicia Margarita
2016-06-01
While wide field surveys have yielded remarkable quantities of photometry of transient objects, including supernovae, light curves reconstructed from this data suffer from several characteristic problems. Because most transients are discovered near the detection limit, signal to noise is generally poor; because coverage is limited to the observing season, light curves are often incomplete; and because temporal sampling can be uneven across filters, these problems can be exacerbated at any one wavelength. While the prevailing approach of modeling individual light curves independently is successful at recovering inferences for the objects with the highest quality observations, it typically neglects a substantial portion of the data and can introduce systematic biases. Joint modeling of the light curves of transient populations enables direct inference on population-level characteristics as well as superior measurements for individual objects. We present a new hierarchical Bayesian model for supernova light curves, where information inferred from observations of every individual light curve in a sample is partially pooled across objects to constrain population-level hyperparameters. Using an efficient Hamiltonian Monte Carlo sampling technique, the model posterior can be explored to enable marginalization over weakly-identified hyperparameters through full Bayesian inference. We demonstrate our technique on the Pan-STARRS1 (PS1) Type IIP supernova light curve sample published by Sanders et al. (2015), consisting of nearly 20,000 individual photometric observations of more than 70 supernovae in five photometric filters. We discuss the Stan probabilistic programming language used to implement the model, computational challenges, and prospects for future work including generalization to multiple supernova types. We also discuss scientific results from the PS1 dataset including a new relation between the peak magnitude and decline rate of SNe IIP, a new perspective on the
Numerical focusing methods for full field OCT: a comparison based on a common signal model.
Kumar, Abhishek; Drexler, Wolfgang; Leitgeb, Rainer A
2014-06-30
In this paper a theoretical model of the full field swept source (FF SS) OCT signal is presented based on the angular spectrum wave propagation approach which accounts for the defocus error with imaging depth. It is shown that using the same theoretical model of the signal, numerical defocus correction methods based on a simple forward model (FM) and inverse scattering (IS), the latter being similar to interferometric synthetic aperture microscopy (ISAM), can be derived. Both FM and IS are compared quantitatively with sub-aperture based digital adaptive optics (DAO). FM has the least numerical complexity, and is the fastest in terms of computational speed among the three. SNR improvement of more than 10 dB is shown for all the three methods over a sample depth of 1.5 mm. For a sample with non-uniform refractive index with depth, FM and IS both improved the depth of focus (DOF) by a factor of 7x for an imaging NA of 0.1. DAO performs the best in case of non-uniform refractive index with respect to DOF improvement by 11x.
Development of full wave code for modeling RF fields in hot non-uniform plasmas
Zhao, Liangji; Svidzinski, Vladimir; Spencer, Andrew; Kim, Jin-Soo
2016-10-01
FAR-TECH, Inc. is developing a full wave RF modeling code to model RF fields in fusion devices and in general plasma applications. As an important component of the code, an adaptive meshless technique is introduced to solve the wave equations, which allows resolving plasma resonances efficiently and adapting to the complexity of antenna geometry and device boundary. The computational points are generated using either a point elimination method or a force balancing method based on the monitor function, which is calculated by solving the cold plasma dispersion equation locally. Another part of the code is the conductivity kernel calculation, used for modeling the nonlocal hot plasma dielectric response. The conductivity kernel is calculated on a coarse grid of test points and then interpolated linearly onto the computational points. All the components of the code are parallelized using MPI and OpenMP libraries to optimize the execution speed and memory. The algorithm and the results of our numerical approach to solving 2-D wave equations in a tokamak geometry will be presented. Work is supported by the U.S. DOE SBIR program.
Modeling of Possible Conditions for Origin of First Organic Forms in hot Mineral Water
Directory of Open Access Journals (Sweden)
Ignat Ignatov
2014-12-01
Full Text Available The composition of water, its temperature and pH value was analyzed in experiments with modelling of primary hydrosphere and possible conditions for origin of first organic forms in hot mineral water. For this aim the authors performed experiments with hot mineral and seawater from Bulgaria by IR-spectrometry (DNES-method. As model systems were used cactus juice of Echinopsis pachanoi and Mediterranean jellyfish Cotylorhiza tuberculata. It was considered the reactions of condensation and dehydration in alkaline aqueous solutions with рН = 9–10, resulting in synthesis from separate molecules larger organic molecules as polymers and short polipeptides. It was shown that hot alkaline mineral water with temperature from +65 0C to +95 0C and pH value from 9 to 11 is more suitable for the origination of life and living matter than other analyzed water samples. The pH value of seawater on contrary is limited to the range of 7,5 to 8,4 units. Two common local maximums were observed in the IR-spectra of jellyfish and seawater, which were more pronouncedly expressed in IR-spectra of jellyfish.
Directory of Open Access Journals (Sweden)
N. Wilkens
2014-09-01
Full Text Available Pine Island Glacier is one of the fastest changing glaciers in the Antarctic Ice Sheet and therefore in scientific focus. The glacier holds enough ice to raise global sea level significantly (∼0.5 m, when fully melted. The question addressed by numerous modelling studies of the glacier focuses on whether the observed changes are a start for an uncontrolled and accelerating retreat. The movement of the glacier is, in the fast flowing areas, dominated by basal motion. In modelling studies the parametrisation of the basal motion is therefore crucial. Inversion methods are commonly applied to reproduce the complex surface flow structure at Pine Island Glacier, which use information of the observed surface velocity field, to constrain basal sliding. We introduce two different approaches of combining a physical parameter, the basal roughness, with basal sliding parametrisations. This way basal sliding is connected again to its original formulation. We show that the basal roughness is an important and helpful parameter to consider and that many features of the flow structure could be reproduced with these approaches.
On a radiative origin of the Standard Model from trinification
Camargo-Molina, José Eliel; Morais, António P.; Pasechnik, Roman; Wessén, Jonas
2016-09-01
In this work, we present a trinification-based grand unified theory incorporating a global SU(3) family symmetry that after a spontaneous breaking leads to a left-right symmetric model. Already at the classical level, this model can accommodate the matter content and the quark Cabbibo mixing in the Standard Model (SM) with only one Yukawa coupling at the unification scale. Considering the minimal low-energy scenario with the least amount of light states, we show that the resulting effective theory enables dynamical breaking of its gauge group down to that of the SM by means of radiative corrections accounted for by the renormalisation group evolution at one loop. This result paves the way for a consistent explanation of the SM breaking scale and fermion mass hierarchies.
The Origin of the RNA World a Kinetic Model
Wattis, J A D; Wattis, Jonathan A. D.; Coveney, Peter V.
1999-01-01
The aims of this paper are to propose, construct and analyse microscopic kinetic models for the emergence of long chains of RNA from monomeric beta-D-ribonucleotide precursors in prebiotic circumstances. Our theory starts out from similar but more general chemical assumptions to those of Eigen, namely that catalytic replication can lead to a large population of long chains. In particular, our models incorporate the possibility of (i) direct chain growth, (ii) template-assisted synthesis and (iii) catalysis by RNA replicase ribozymes, all with varying degrees of efficiency. However, in our models the reaction mechanisms are kept `open'; we do not assume the existence of closed hypercycles which sustain a population of long chains. Rather it is the feasibility of the initial emergence of a self-sustaining set of RNA chains from monomeric nucleotides which is our prime concern. We confront directly the central nonlinear features of the problem, which have often been overlooked in previous studies. Our detailed m...
On a radiative origin of the Standard Model from Trinification
Camargo-Molina, José Eliel; Pasechnik, Roman; Wessén, Jonas
2016-01-01
In this work, we present a trinification-based Grand Unified Theory (GUT) incorporating a global $\\mathrm{SU}(3)$ flavor symmetry that after a spontaneous breaking leads to a Left-Right (LR) symmetric model. Already at the classical level, this model can accommodate the matter content and the quark Cabbibo mixing in the Standard Model (SM) with only one Yukawa coupling at the unification scale. Considering the minimal low-energy scenario with the least amount of light states, we show that the resulting effective theory enables dynamical breaking of its gauge group down to that of the SM by means of radiative corrections accounted for by the Renormalisation Group evolution at one loop. This result paves the way for a consistent explanation of the SM breaking scale and hierarchies.
Modelling and Testing of Wave Dragon Wave Energy Converter Towards Full Scale Deployment
DEFF Research Database (Denmark)
Parmeggiani, Stefano
-commercial stage in which it has proven difficult to secure the necessary funding for the deployment of a full-scale demonstrator unit. The work presented aims at easing this process, by increasing public and scientific knowledge of the device, as well as by showing the latest progress in its development. Research....... This is mainly due to the development of an updated overtopping model specifically suited to Wave Dragon, which allows greater quality to predictions of the primary energy absorption of the device compared to previous versions. At the same time an equitable approach has been described and used in the performance......, the research has also provided a deeper insight into the physics of the overtopping process by individually assessing the influence of related device configuration and wave features, which goes beyond the present application and may be used for other overtopping WECs as well. Comprehensive analysis...
Portfolio optimization in a defaults model under full/partial information
Lim, Thomas
2010-01-01
In this paper, we consider a financial market with assets exposed to some risks inducing jumps in the asset prices, and which can still be traded after default times. We use a default-intensity modeling approach, and address in this incomplete market context the problem of maximization of expected utility from terminal wealth for logarithmic, power and exponential utility functions. We study this problem as a stochastic control problem both under full and partial information. Our contribution consists in showing that the optimal strategy can be obtained by a direct approach for the logarithmic utility function, and the value function for the power utility function can be determined as the minimal solution of a backward stochastic differential equation. For the partial information case, we show how the problem can be divided into two problems: a filtering problem and an optimization problem. We also study the indifference pricing approach to evaluate the price of a contingent claim in an incomplete market and ...
Energy Technology Data Exchange (ETDEWEB)
Tareyeva, E.E. [Institute for High Pressure Physics, Russian Academy of Sciences, 142190 Troitsk (Russian Federation); Schelkacheva, T.I., E-mail: tanschelk@gmail.com [Institute for High Pressure Physics, Russian Academy of Sciences, 142190 Troitsk (Russian Federation); Chtchelkatchev, N.M. [Institute for High Pressure Physics, Russian Academy of Sciences, 142190 Troitsk (Russian Federation); L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 117940 Moscow (Russian Federation); Department of Theoretical Physics, Moscow Institute of Physics and Technology, 141700 Moscow (Russian Federation)
2013-02-15
We investigate near the point of glass transition the expansion of the free energy corresponding to the generalized Sherrington–Kirkpatrick model with arbitrary diagonal operators U{sup -hat} standing instead of Ising spins. We focus on the case when U{sup -hat} is an operator with broken reflection symmetry. Such a consideration is important for understanding the behavior of spin glass-like phases in a number of real physical systems, mainly in orientational glasses in mixed molecular crystals which present just the case. We build explicitly a full replica symmetry breaking (FRSB) solution of the equations for the orientational glass order parameters when the nonsymmetric part of U{sup -hat} is small. This particular result presents a counterexample in the context of usually adopted conjecture of the absence of FRSB solution in systems with no reflection symmetry.
Finite Element Modelling Full Vehicle Side Impact with Ultrahigh Strength Hot Stamped Steels
Taylor, T.; Fourlaris, G.; Cafolla, J.
2016-10-01
"Hot stamped boron steel" 22MnB5 has been imperative in meeting the automotive industry's demand for materials exhibiting higher tensile strength in the final component. In this paper, the crash performance of three experimental grades developed for automotive hot stamping technologies, exhibiting wider tensile property ranges than 22MnB5, was validated by finite element modelling full vehicle side impact with the experimental material data applied to the B-pillar reinforcement. The superior anti-intrusive crash performance of grade 38MnB5 was demonstrated, with 11 mm less intrusion of the B-pillar reinforcement compared to 22MnB5. Moreover, the superior "impact-energy absorptive" crash performance of grade 15MnCr5 was demonstrated, with 0.15 kJ greater impact-energy absorption by the B-pillar reinforcement compared to 22MnB5.
Tareyeva, E. E.; Schelkacheva, T. I.; Chtchelkatchev, N. M.
2013-02-01
We investigate near the point of glass transition the expansion of the free energy corresponding to the generalized Sherrington-Kirkpatrick model with arbitrary diagonal operators Uˆ standing instead of Ising spins. We focus on the case when Uˆ is an operator with broken reflection symmetry. Such a consideration is important for understanding the behavior of spin glass-like phases in a number of real physical systems, mainly in orientational glasses in mixed molecular crystals which present just the case. We build explicitly a full replica symmetry breaking (FRSB) solution of the equations for the orientational glass order parameters when the nonsymmetric part of Uˆ is small. This particular result presents a counterexample in the context of usually adopted conjecture of the absence of FRSB solution in systems with no reflection symmetry.
Radiative capture reaction for 17Ne formation within a full three-body model
Casal, J.; Garrido, E.; de Diego, R.; Arias, J. M.; Rodríguez-Gallardo, M.
2016-11-01
Background: The breakout from the hot Carbon-Nitrogen-Oxigen (CNO) cycles can trigger the rp-process in type I x-ray bursts. In this environment, a competition between 15O(α ,γ )19Ne and the two-proton capture reaction 15O(2 p ,γ )17Ne is expected. Purpose: Determine the three-body radiative capture reaction rate for 17Ne formation including sequential and direct, resonant and nonresonant contributions on an equal footing. Method: Two different discretization methods have been applied to generate 17Ne states in a full three-body model: the analytical transformed harmonic oscillator method and the hyperspherical adiabatic expansion method. The binary p -15O interaction has been adjusted to reproduce the known spectrum of the unbound 16F nucleus. The dominant E 1 contributions to the 15O(2 p ,γ )17Ne reaction rate have been calculated from the inverse photodissociation process. Results: Three-body calculations provide a reliable description of 17Ne states. The agreement with the available experimental data on 17Ne is discussed. It is shown that the 15O(2 p ,γ )17Ne reaction rates computed within the two methods agree in a broad range of temperatures. The present calculations are compared with a previous theoretical estimation of the reaction rate. Conclusions: It is found that the full three-body model provides a reaction rate several orders of magnitude larger than the only previous estimation. The implications for the rp-process in type I x-ray bursts should be investigated.
Directory of Open Access Journals (Sweden)
Kerstin Reisinger
2015-06-01
Full Text Available The 3D Skin Comet assay was developed to improve the in vitro prediction of the genotoxic potential of dermally applied chemicals. For this purpose, a classical read-out for genotoxicity (i.e. comet formation was combined with reconstructed 3D skin models as well-established test systems. Five laboratories (BASF, BfR (Federal Institute for Risk Assessment, Henkel, Procter & Gamble and TNO Triskilion started to validate this assay using the Phenion® Full- Thickness (FT Skin Model and 8 coded chemicals with financial support by Cosmetics Europe and the German Ministry of Education & Research. There was an excellent overall predictivity of the expected genotoxicity (>90%. Four labs correctly identified all chemicals and the fifth correctly identified 80% of the chemicals. Background DNA damage was low and values for solvent (acetone and positive (methyl methanesulfonate (MMS controls were comparable among labs. Inclusion of the DNA-polymerase inhibitor, aphidicolin (APC, in the protocol improved the predictivity of the assay since it enabled robust detection of pro-mutagens e.g., 7,12-dimethylbenz[a]anthracene and benzo[a]pyrene. Therefore, all negative findings are now confirmed by additional APC experiments to come to a final conclusion. Furthermore, MMC, which intercalates between DNA strands causing covalent binding, was detected with the standard protocol, in which it gave weak but statistically significant responses. Stronger responses, however, were obtained using a cross-linker specific protocol in which MMC reduced the migration of MMS-induced DNA damage. These data support the use of the Phenion® FT in the Comet assay: no false-positives and only one false-negative finding in a single lab. Testing will continue to obtain data for 30 chemicals. Once validated, the 3D Skin Comet assay is foreseen to be used as a follow-up test for positive results from the current in vitro genotoxicity test battery.
Marciniak, Karyn
2017-03-01
The majority of research on sibling relationships has investigated only one or two siblings in a family, but there are many theoretical and methodological limitations to this single dyadic perspective. This study uses multiple siblings (541 adults) in 184 families, where 96 of these families had all siblings complete the study, to demonstrate the value in including full sibling groups when conducting research on sibling relationships. Two scales, positivity and willingness to sacrifice, are evaluated with a multilevel model to account for the nested nature of family relationships. The distribution of variance across three levels: relationship, individual, and family are computed, and results indicate that the relationship level explains the most variance in positivity, whereas the individual level explains the majority of variance in willingness to sacrifice. These distributions are affected by gender composition and family size. The results of this study highlight an important and often overlooked element of family research: The meaning of a scale changes based on its distribution of variance at these three levels. Researchers are encouraged to be cognizant of the variance distribution of their scales when studying sibling relationships and to incorporate more full sibling groups into their research methods and study design. © 2015 Family Process Institute.
The two-process model : Origin and perspective
Daan, S.; Hut, R. A.; Beersma, D.
2014-01-01
In the two-process model as developed in the early 1980's sleep is controlled by a process-S, representing the rise and fall of sleep demand resulting from prior sleep-wake history, interacting with a process-C representing circadian variation in sleep propensity. S and C together optimize sleep tim
The two-process model : Origin and perspective
Daan, S.; Hut, R. A.; Beersma, D.
In the two-process model as developed in the early 1980's sleep is controlled by a process-S, representing the rise and fall of sleep demand resulting from prior sleep-wake history, interacting with a process-C representing circadian variation in sleep propensity. S and C together optimize sleep
Particle model of full-size ITER-relevant negative ion source.
Taccogna, F; Minelli, P; Ippolito, N
2016-02-01
This work represents the first attempt to model the full-size ITER-relevant negative ion source including the expansion, extraction, and part of the acceleration regions keeping the mesh size fine enough to resolve every single aperture. The model consists of a 2.5D particle-in-cell Monte Carlo collision representation of the plane perpendicular to the filter field lines. Magnetic filter and electron deflection field have been included and a negative ion current density of j(H(-)) = 660 A/m(2) from the plasma grid (PG) is used as parameter for the neutral conversion. The driver is not yet included and a fixed ambipolar flux is emitted from the driver exit plane. Results show the strong asymmetry along the PG driven by the electron Hall (E × B and diamagnetic) drift perpendicular to the filter field. Such asymmetry creates an important dis-homogeneity in the electron current extracted from the different apertures. A steady state is not yet reached after 15 μs.
Particle model of full-size ITER-relevant negative ion source
Energy Technology Data Exchange (ETDEWEB)
Taccogna, F., E-mail: francesco.taccogna@nanotec.cnr.it; Minelli, P. [CNR-Nanotec, Bari 70126 (Italy); INFN, Bari 70126 (Italy); Ippolito, N. [INFN, Bari 70126 (Italy)
2016-02-15
This work represents the first attempt to model the full-size ITER-relevant negative ion source including the expansion, extraction, and part of the acceleration regions keeping the mesh size fine enough to resolve every single aperture. The model consists of a 2.5D particle-in-cell Monte Carlo collision representation of the plane perpendicular to the filter field lines. Magnetic filter and electron deflection field have been included and a negative ion current density of j{sub H{sup −}} = 660 A/m{sup 2} from the plasma grid (PG) is used as parameter for the neutral conversion. The driver is not yet included and a fixed ambipolar flux is emitted from the driver exit plane. Results show the strong asymmetry along the PG driven by the electron Hall (E × B and diamagnetic) drift perpendicular to the filter field. Such asymmetry creates an important dis-homogeneity in the electron current extracted from the different apertures. A steady state is not yet reached after 15 μs.
Biosorption of Ni(II) by Fig Male: Optimization and Modeling Using a Full Factorial Design.
Madjene, F; Chergui, A; Trari, M
2016-06-01
The fig male (FM) is successfully used as biosorbent for Ni(2+) removal. The maximum removal efficiency (96.6%) is obtained at pH ~ 5 for a concentration of 1.70 mmol L(-1) and catalyst dose of 5 g L(-1) in less than 10 minutes. The Ni(2+) uptake follows a pseudo-second-order kinetic, the rate constants increase with increasing temperature, and an activation energy of 55.48 kJ mol(-1) is found. The thermodynamic parameters indicate a spontaneous endothermic bisorption. The isotherm data are fitted by the Langmuir and Dubinin-Radushkevich models. The former indicates a maximum Ni(2+) uptake of 0.459 mmol g(-1), which is higher than that of most biosorbents investigated to date. The FTIR spectra reveal the biosorption mechanism between Ni(2+) and FM functional groups. An empirical modeling is performed by using a 2(3) full factorial design, and a regression equation for Ni(2+) biosorption is determined. The biosorbent mass and pH are the most significant parameters affecting the Ni(2+) biosorption.
Full-scale simulation and reduced-order modeling of a thermoacoustic engine
Scalo, Carlo; Lin, Jeff; Lele, Sanjiva; Hesselink, Lambertus
2013-11-01
We have carried out the first three-dimensional numerical simulation of a thermoacoustic Stirling heat-engine. The goal is to lay the groundwork for full-scale Navier-Stokes simulations to advance the state-of-the-art low-order modeling and design of such devices. The model adopted is a long resonator with a heat-exchanger/regenerator (HX/REG) unit on one end - the only component not directly resolved. A temperature difference across the HX/REG unit of 200 K is sufficient to initiate the thermoacoustic instability. The latter is a Lagrangian process that only intensifies acoustic waves traveling in the direction of the imposed temperature gradient. An acoustic network of traveling waves is thus obtained and compared against low-order prediction tools such as DeltaEC. Non-linear effects such as system-wide streaming flow patterns are rapidly established. These are responsible for the mean advection of hot fluid away from the HX/REG (i.e. thermal leakage). This unwanted effect is contained by the introduction of a second ambient heat-exchanger allowing for the establishment of a dynamical thermal equilibrium in the system. A limit cycle is obtained at +178 dB.
A porcine model of full-thickness burn, excision and skin autografting
Branski, Ludwik K.; Mittermayr, Rainer; Herndon, David N.; Norbury, William B.; Masters, Oscar E.; Hofmann, Martina; Traber, Daniel L.; Redl, Heinz; Jeschke, Marc G.
2008-01-01
Acute burn wounds often require early excision and adequate coverage to prevent further hypothermia, protein and fluid losses, and the risk of infection. Meshed autologous skin grafts are generally regarded as the standard treatment for extensive full-thickness burns. Graft take and rate of wound healing, however, depend on several endogenous factors. This paper describes a standardized reproducible porcine model of burn and skin grafting which can be used to study the effects of topical treatments on graft take and re-epithelialization. Procedures provide a protocol for successful porcine burn wound experiments with special focus on pre-operative care, anesthesia, burn allocation, excision and grafting, postoperative treatment, dressing application, and specimen collection. Selected outcome measurements include percent area of wound closure by planimetry, wound assessment using a clinical assessment scale, and histological scoring. The use of this standardized model provides burn researchers with a valuable tool for the comparison of different topical drug treatments and dressing materials in a setting that closely mimics clinical reality. PMID:18617332
Particle model of full-size ITER-relevant negative ion source
Taccogna, F.; Minelli, P.; Ippolito, N.
2016-02-01
This work represents the first attempt to model the full-size ITER-relevant negative ion source including the expansion, extraction, and part of the acceleration regions keeping the mesh size fine enough to resolve every single aperture. The model consists of a 2.5D particle-in-cell Monte Carlo collision representation of the plane perpendicular to the filter field lines. Magnetic filter and electron deflection field have been included and a negative ion current density of jH- = 660 A/m2 from the plasma grid (PG) is used as parameter for the neutral conversion. The driver is not yet included and a fixed ambipolar flux is emitted from the driver exit plane. Results show the strong asymmetry along the PG driven by the electron Hall (E × B and diamagnetic) drift perpendicular to the filter field. Such asymmetry creates an important dis-homogeneity in the electron current extracted from the different apertures. A steady state is not yet reached after 15 μs.
A modified full velocity difference model with the consideration of velocity deviation
Zhou, Jie; Shi, Zhong-Ke
2016-01-01
In this paper, a modified full velocity difference model (FVDM) based on car-following theory is proposed with the consideration of velocity deviation which represents the inexact judgement of velocity. The stability condition is obtained by the use of linear stability analysis. It is shown that the stability of traffic flow varies with the deviation extent of velocity. The Burgers, Korteweg-de Vries (KdV) and modified K-dV (MKdV) equations are derived to describe the triangular shock waves, soliton waves and kink-antikink waves in the stable, metastable and unstable region, respectively. The numerical simulations show a good agreement with the analytical results, such as density wave, hysteresis loop, acceleration, deceleration and so on. The results show that traffic congestion can be suppressed by taking the positive effect of velocity deviation into account. By taking the positive effect of high estimate of velocity into account, the unrealistic high deceleration and negative velocity which occur in FVDM will be eliminated in the proposed model.
Enhanced Doppler reflectometry power response: physical optics and 2D full wave modelling
Pinzón, J. R.; Happel, T.; Blanco, E.; Conway, G. D.; Estrada, T.; Stroth, U.
2017-03-01
The power response of a Doppler reflectometer is investigated by means of the physical optics model; a simple model which considers basic scattering processes at the reflection layer. Apart from linear and saturated scattering regimes, non-linear regimes with an enhanced backscattered power are found. The different regimes are characterized and understood based on analytical calculations. The power response is also studied with two-dimensional full wave simulations, where the enhanced backscattered power regimes are also found in qualitative agreement with the physical optics results. The ordinary and extraordinary modes are compared for the same angle of incidence, with the conclusion that the ordinary mode is better suited for Doppler reflectometry turbulence level measurements due to the linearity of its response. The scattering efficiency is studied and a first approximation to describe it is proposed. At the end, the application of the physical optics results to experimental data analysis is discussed. In particular, a formula to assess the linearity of Doppler reflectometry measurements is provided.
Achieving Full Dynamic Similarity with Small-Scale Wind Turbine Models
Miller, Mark; Kiefer, Janik; Westergaard, Carsten; Hultmark, Marcus
2016-11-01
Power and thrust data as a function of Reynolds number and Tip Speed Ratio are presented at conditions matching those of a full scale turbine. Such data has traditionally been very difficult to acquire due to the large length-scales of wind turbines, and the limited size of conventional wind tunnels. Ongoing work at Princeton University employs a novel, high-pressure wind tunnel (up to 220 atmospheres of static pressure) which uses air as the working fluid. This facility allows adjustment of the Reynolds number (via the fluid density) independent of the Tip Speed Ratio, up to a Reynolds number (based on chord and velocity at the tip) of over 3 million. Achieving dynamic similarity using this approach implies very high power and thrust loading, which results in mechanical loads greater than 200 times those experienced by a similarly sized model in a conventional wind tunnel. In order to accurately report the power coefficients, a series of tests were carried out on a specially designed model turbine drive-train using an external testing bench to replicate tunnel loading. An accurate map of the drive-train performance at various operating conditions was determined. Finally, subsequent corrections to the power coefficient are discussed in detail. Supported by: National Science Foundation Grant CBET-1435254 (program director Gregory Rorrer).
Modeling the angular correlation function and its full covariance in Photometric Galaxy Surveys
Crocce, Martin; Gaztañaga, Enrique
2010-01-01
Near future cosmology will see the advent of wide area photometric galaxy surveys, like the Dark Energy Survey (DES), that extent to high redshifts (z ~ 1 - 2) but with poor radial distance resolution. In such cases splitting the data into redshift bins and using the angular correlation function $w(\\theta)$, or the $C_{\\ell}$ power spectrum, will become the standard approach to extract cosmological information or to study the nature of dark energy through the Baryon Acoustic Oscillations (BAO) probe. In this work we present a detailed model for $w(\\theta)$ at large scales as a function of redshift and bin width, including all relevant effects, namely nonlinear gravitational clustering, bias, redshift space distortions and photo-z uncertainties. We also present a model for the full covariance matrix characterizing the angular correlation measurements, that takes into account the same effects as for $w(\\theta)$ and also the possibility of a shot-noise component and partial sky coverage. Provided with a large vo...
Delta r in the Two-Higgs-Doublet Model at full one loop level -- and beyond
Lopez-Val, David
2012-01-01
After the recent discovery of a Higgs-like boson particle at the CERN LHC-collider, it becomes more necessary than ever to prepare ourselves for identifying its standard or non-standard nature. The Electroweak parameter Delta r relating the values of the gauge boson masses [MW,MZ] and the Fermi constant [G_F] is the traditional observable encoding high precision information of the electroweak physics at the quantum level. In this work we present a complete quantitative study of Delta r in the framework of the general (unconstrained) Two-Higgs-Doublet Model (2HDM). First of all we report on a systematic analysis of Delta r at the full one loop level in the general 2HDM, which to our knowledge was missing in the literature. Thereby we extract a theoretical prediction for the mass of the W-boson in this model, taking MZ, \\alpha_{em} and G_F as experimental inputs. We find typical corrections leading to mass shifts $\\delta MW \\sim 20-40 MeV$ which help to improve the agreement with the experimentally measured val...
Salas, Margaux M; McIntyre, Matthew K; Petz, Lawrence N; Korz, Walter; Wong, Donald; Clifford, John L
2015-10-21
Burn injuries have been identified as the primary cause of injury in 5% of U.S. military personnel evacuated from Operations Iraqi Freedom and Enduring Freedom. Severe burn-associated pain is typically treated with opioids such as fentanyl, morphine, and methadone. Side effects of opioids include respiratory depression, cardiac depression, decrease in motor and cognitive function, as well as the development of hyperalgesia, tolerance and dependence. These effects have led us to search for novel analgesics for the treatment of burn-associated pain in wounded combat service members. Tetrodotoxin (TTX) is a selective voltage-gated sodium channel blocker currently in clinical trials as an analgesic. A phase 3 clinical trial for cancer-related pain has been completed and phase 3 clinical trials on chemotherapy-induced neuropathic pain are planned. It has also been shown in mice to inhibit the development of chemotherapy-induced neuropathic pain. TTX was originally identified as a neurotoxin in marine animals but has now been shown to be safe in humans at therapeutic doses. The antinociceptive effects of TTX are thought to be due to inhibition of Na(+) ion influx required for initiation and conduction of nociceptive impulses. One TTX sensitive sodium channel, Nav1.7, has been shown to be essential in lowering the heat pain threshold after burn injuries. To date, the analgesic effect of TTX has not been tested in burn-associated pain. Male Sprague-Dawley rats were subjected to a full thickness thermal injury on the right hind paw. TTX (8 μg/kg) was administered once a day systemically by subcutaneous injection beginning 3 days post thermal injury and continued through 7 days post thermal injury. Thermal hyperalgesia and mechanical allodynia were assessed 60 and 120 min post injection on each day of TTX treatment. TTX significantly reduced thermal hyperalgesia at all days tested and had a less robust, but statistically significant suppressive effect on mechanical
The origin of discrete symmetries in F-theory models
2015-01-01
While non-abelian groups are undoubtedly the cornerstone of Grand Unified Theories (GUTs), phenomenology shows that the role of abelian and discrete symmetries is equally important in model building. The latter are the appropriate tool to suppress undesired proton decay operators and various flavour violating interactions, to generate a hierarchical fermion mass spectrum, etc. In F-theory, GUT symmetries are linked to the singularities of the elliptically fibred K3 manifolds; they are of ADE ...
Beebe, Beatrice; Lachmann, Frank; Markese, Sara; Bahrick, Lorraine
2012-01-01
Despite important recent progress in understanding disorganized attachment, we still lack a full understanding of the mechanisms of disorganized attachment formation and transmission prior to 12 months. In this paper we lay out our recommendations for the study of the 4-month origins of disorganized attachment. In our subsequent Paper II we report on the results of a large empirical study that was conducted along the lines we recommend in Paper I. Both Papers I and II are based on Beebe, Jaffe, Markese, Buck, Chen, Cohen, Bahrick, Andrews, Feldstein (2010). In Paper I we describe our proposal that a detailed microanalysis of 4-month mother-infant face-to-face communication would further inform our understanding of the process of disorganized attachment formation between mother and infant. Such a microanalysis would allow us to characterize the nature of the 4-month infant's procedural representations, or emerging "internal working models" of attachment.
The statistical multifragmentation model: Origins and recent advances
Donangelo, R.; Souza, S. R.
2016-07-01
We review the Statistical Multifragmentation Model (SMM) which considers a generalization of the liquid-drop model for hot nuclei and allows one to calculate thermodynamic quantities characterizing the nuclear ensemble at the disassembly stage. We show how to determine probabilities of definite partitions of finite nuclei and how to determine, through Monte Carlo calculations, observables such as the caloric curve, multiplicity distributions, heat capacity, among others. Some experimental measurements of the caloric curve confirmed the SMM predictions of over 10 years before, leading to a surge in the interest in the model. However, the experimental determination of the fragmentation temperatures relies on the yields of different isotopic species, which were not correctly calculated in the schematic, liquid-drop picture, employed in the SMM. This led to a series of improvements in the SMM, in particular to the more careful choice of nuclear masses and energy densities, specially for the lighter nuclei. With these improvements the SMM is able to make quantitative determinations of isotope production. We show the application of SMM to the production of exotic nuclei through multifragmentation. These preliminary calculations demonstrate the need for a careful choice of the system size and excitation energy to attain maximum yields.
The statistical multifragmentation model: Origins and recent advances
Energy Technology Data Exchange (ETDEWEB)
Donangelo, R., E-mail: donangel@fing.edu.uy [Instituto de Física, Facultad de Ingeniería, Universidad de la República, Julio Herrera y Reissig 565, 11300, Montevideo (Uruguay); Instituto de Física, Universidade Federal do Rio de Janeiro, C.P. 68528, 21941-972 Rio de Janeiro - RJ (Brazil); Souza, S. R., E-mail: srsouza@if.ufrj.br [Instituto de Física, Universidade Federal do Rio de Janeiro, C.P. 68528, 21941-972 Rio de Janeiro - RJ (Brazil); Instituto de Física, Universidade Federal do Rio Grande do Sul, C.P. 15051, 91501-970 Porto Alegre - RS (Brazil)
2016-07-07
We review the Statistical Multifragmentation Model (SMM) which considers a generalization of the liquid-drop model for hot nuclei and allows one to calculate thermodynamic quantities characterizing the nuclear ensemble at the disassembly stage. We show how to determine probabilities of definite partitions of finite nuclei and how to determine, through Monte Carlo calculations, observables such as the caloric curve, multiplicity distributions, heat capacity, among others. Some experimental measurements of the caloric curve confirmed the SMM predictions of over 10 years before, leading to a surge in the interest in the model. However, the experimental determination of the fragmentation temperatures relies on the yields of different isotopic species, which were not correctly calculated in the schematic, liquid-drop picture, employed in the SMM. This led to a series of improvements in the SMM, in particular to the more careful choice of nuclear masses and energy densities, specially for the lighter nuclei. With these improvements the SMM is able to make quantitative determinations of isotope production. We show the application of SMM to the production of exotic nuclei through multifragmentation. These preliminary calculations demonstrate the need for a careful choice of the system size and excitation energy to attain maximum yields.
Franz, Delbert D.; Melching, Charles S.
1997-01-01
The Full EQuations (FEQ) model is a computer program for solution of the full, dynamic equations of motion for one-dimensional unsteady flow in open channels and through control structures. A stream system that is simulated by application of FEQ is subdivided into stream reaches (branches), parts of the stream system for which complete information on flow and depth are not required (dummy branches), and level-pool reservoirs. These components are connected by special features; that is, hydraulic control structures, including junctions, bridges, culverts, dams, waterfalls, spillways, weirs, side weirs, and pumps. The principles of conservation of mass and conservation of momentum are used to calculate the flow and depth throughout the stream system resulting from known initial and boundary conditions by means of an implicit finite-difference approximation at fixed points (computational nodes). The hydraulic characteristics of (1) branches including top width, area, first moment of area with respect to the water surface, conveyance, and flux coefficients and (2) special features (relations between flow and headwater and (or) tail-water elevations, including the operation of variable-geometry structures) are stored in function tables calculated in the companion program, Full EQuations UTiLities (FEQUTL). Function tables containing other information used in unsteady-flow simulation (boundary conditions, tributary inflows or outflows, gate settings, correction factors, characteristics of dummy branches and level-pool reservoirs, and wind speed and direction) are prepared by the user as detailed in this report. In the iterative solution scheme for flow and depth throughout the stream system, an interpolation of the function tables corresponding to the computational nodes throughout the stream system is done in the model. FEQ can be applied in the simulation of a wide range of stream configurations (including loops), lateral-inflow conditions, and special features. The
Full Model Wind Tunnel Study on the Xia-Zhang Bridge Under Operation Stage
Directory of Open Access Journals (Sweden)
Ayad T. Saeed
2010-01-01
Full Text Available Problem statement: Long-span cable-stayed bridges under service and particular construction conditions are very susceptible to wind action due to their great flexibility, so the aerodynamic stability is becoming a major concern in the design and construction phrases. Cable-stayed bridges may exhibit wind-induced vibration phenomena such as flutter, buffeting and vortex oscillation under wind excitation. The study concentrated on the issues concerning the aerodynamic response of Xia-Zhang cable-stayed Bridge to make it safe and stable under wind action. Although there have been accumulating experience in the building of cable-stayed bridges and research on wind-resistant stability in Chinese Mainland, most of the research focuses on inland cable-stayed bridges or littoral ones of mid-length, but not on littoral ones whose main span is over 600 m. Therefore, wind-resistant performance research of north branch bridge of Xia-Zhang cross-sea Bridges is very necessary and important for its wind-resistant stability, safety and applicability in the operation condition. Approach: This study mainly presented the wind tunnel test program of the Xia-Zhang Bridge aeroelastic full model, including test method, test contents, test results and so on. Results: The test results contained Root Mean Square (RMS of accelerations and displacements as well as average values of displacements. Conclusion: The conclusions were as follows: (a In the uniform flow field, under the condition of entire bridge without rail may vibration divergence occur when α = 3°, V>122 m sec-1. (b No vortex-induced vibration with extreme amplitudes or static collapsing was detected in all the testing conditions. (c In the turbulent flow field, there were very obvious buffeting phenomena. Responses to turbulence are quite intense.
Towards Achieving the Full Clinical Potential of Proton Therapy by Inclusion of LET and RBE Models
Directory of Open Access Journals (Sweden)
Bleddyn Jones
2015-03-01
Full Text Available Despite increasing use of proton therapy (PBT, several systematic literature reviews show limited gains in clinical outcomes, with publications mostly devoted to recent technical developments. The lack of randomised control studies has also hampered progress in the acceptance of PBT by many oncologists and policy makers. There remain two important uncertainties associated with PBT, namely: (1 accuracy and reproducibility of Bragg peak position (BPP; and (2 imprecise knowledge of the relative biological effect (RBE for different tissues and tumours, and at different doses. Incorrect BPP will change dose, linear energy transfer (LET and RBE, with risks of reduced tumour control and enhanced toxicity. These interrelationships are discussed qualitatively with respect to the ICRU target volume definitions. The internationally accepted proton RBE of 1.1 was based on assays and dose ranges unlikely to reveal the complete range of RBE in the human body. RBE values are not known for human (or animal brain, spine, kidney, liver, intestine, etc. A simple efficiency model for estimating proton RBE values is described, based on data of Belli et al. and other authors, which allows linear increases in α and β with LET, with a gradient estimated using a saturation model from the low LET α and β radiosensitivity parameter input values, and decreasing RBE with increasing dose. To improve outcomes, 3-D dose-LET-RBE and bio-effectiveness maps are required. Validation experiments are indicated in relevant tissues. Randomised clinical studies that test the invariant 1.1 RBE allocation against higher values in late reacting tissues, and lower tumour RBE values in the case of radiosensitive tumours, are also indicated.
Global sensitivity analysis in the identification of cohesive models using full-field kinematic data
Alfano, Marco
2015-03-01
Failure of adhesive bonded structures often occurs concurrent with the formation of a non-negligible fracture process zone in front of a macroscopic crack. For this reason, the analysis of damage and fracture is effectively carried out using the cohesive zone model (CZM). The crucial aspect of the CZM approach is the precise determination of the traction-separation relation. Yet it is usually determined empirically, by using calibration procedures combining experimental data, such as load-displacement or crack length data, with finite element simulation of fracture. Thanks to the recent progress in image processing, and the availability of low-cost CCD cameras, it is nowadays relatively easy to access surface displacements across the fracture process zone using for instance Digital Image Correlation (DIC). The rich information provided by correlation techniques prompted the development of versatile inverse parameter identification procedures combining finite element (FE) simulations and full field kinematic data. The focus of the present paper is to assess the effectiveness of these methods in the identification of cohesive zone models. In particular, the analysis is developed in the framework of the variance based global sensitivity analysis. The sensitivity of kinematic data to the sought cohesive properties is explored through the computation of the so-called Sobol sensitivity indexes. The results show that the global sensitivity analysis can help to ascertain the most influential cohesive parameters which need to be incorporated in the identification process. In addition, it is shown that suitable displacement sampling in time and space can lead to optimized measurements for identification purposes.
Structural characterization suggests models for monomeric and dimeric forms of full-length ezrin.
Phang, Juanita M; Harrop, Stephen J; Duff, Anthony P; Sokolova, Anna V; Crossett, Ben; Walsh, James C; Beckham, Simone A; Nguyen, Cuong D; Davies, Roberta B; Glöckner, Carina; Bromley, Elizabeth H C; Wilk, Krystyna E; Curmi, Paul M G
2016-09-15
Ezrin is a member of the ERM (ezrin-radixin-moesin) family of proteins that have been conserved through metazoan evolution. These proteins have dormant and active forms, where the latter links the actin cytoskeleton to membranes. ERM proteins have three domains: an N-terminal FERM [band Four-point-one (4.1) ERM] domain comprising three subdomains (F1, F2, and F3); a helical domain; and a C-terminal actin-binding domain. In the dormant form, FERM and C-terminal domains form a stable complex. We have determined crystal structures of the active FERM domain and the dormant FERM:C-terminal domain complex of human ezrin. We observe a bistable array of phenylalanine residues in the core of subdomain F3 that is mobile in the active form and locked in the dormant form. As subdomain F3 is pivotal in binding membrane proteins and phospholipids, these transitions may facilitate activation and signaling. Full-length ezrin forms stable monomers and dimers. We used small-angle X-ray scattering to determine the solution structures of these species. As expected, the monomer shows a globular domain with a protruding helical coiled coil. The dimer shows an elongated dumbbell structure that is twice as long as the monomer. By aligning ERM sequences spanning metazoan evolution, we show that the central helical region is conserved, preserving the heptad repeat. Using this, we have built a dimer model where each monomer forms half of an elongated antiparallel coiled coil with domain-swapped FERM:C-terminal domain complexes at each end. The model suggests that ERM dimers may bind to actin in a parallel fashion.
Energy Technology Data Exchange (ETDEWEB)
Ferda, Jiri [Department of Nuclear Medicine, Charles University Medical School and Teaching Hospital, Plzen (Czech Republic); Radiodiagnostic Clinic, Charles University Medical School and Teaching Hospital, Plzen (Czech Republic)], E-mail: ferda@fnplzen.cz; Ferdova, Eva [Department of Nuclear Medicine, Charles University Medical School and Teaching Hospital, Plzen (Czech Republic); Radiodiagnostic Clinic, Charles University Medical School and Teaching Hospital, Plzen (Czech Republic); Zahlava, Jan [Department of Nuclear Medicine, Charles University Medical School and Teaching Hospital, Plzen (Czech Republic); Matejovic, Martin [Ist Internal Department, Charles University Medical School and Teaching Hospital, Plzen (Czech Republic); Kreuzberg, Boris [Radiodiagnostic Clinic, Charles University Medical School and Teaching Hospital, Plzen (Czech Republic)
2010-03-15
Aim: The aim of presented work is to evaluate the clinical value of {sup 18}F-FDG-PET/CT in patients with fever of unknown origin (FUO) and to compare PET/CT finding with the results of the following investigation. Material and method: 48 patients (24 men, 24 women, mean age 57.6 years with range 15-89 years) underwent {sup 18}F-FDG-PET/CT due to the fever of unknown origin. All examinations were performed using complex PET/CT protocol combined PET and whole diagnostic contrast enhanced CT with sub-millimeter spatial resolution (except patient with history of iodine hypersensitivity or sever renal impairment). CT data contained diagnostic images reconstructed with soft tissue and high-resolution algorithm. PET/CT finding were compared with results of biopsies, immunology, microbiology or autopsy. Results: The cause of FUO was explained according to the PET/CT findings and followed investigations in 44 of 48 cases-18 cases of microbial infections, nine cases of autoimmune inflammations, four cases of non-infectious granulomatous diseases, eight cases of malignancies and five cases of proved immunity disorders were found. In 46 cases, the PET/CT interpretation was correct. Only in one case, the cause was overlooked and the uptake in atherosclerotic changes of arteries was misinterpreted as vasculitis in the other. The reached sensitivity was 97% (43/44), and specificity 75% (3/4) respectively. Conclusion: In patients with fever of unknown origin, {sup 18}F-FDG-PET/CT might enable the detection of its cause.
A spatial interaction model with spatially structured origin and destination effects
LeSage, James P.; Llano, Carlos
2013-07-01
We introduce a Bayesian hierarchical regression model that extends the traditional least-squares regression model used to estimate gravity or spatial interaction relations involving origin-destination flows. Spatial interaction models attempt to explain variation in flows from n origin regions to n destination regions resulting in a sample of N = n 2 observations that reflect an n by n flow matrix converted to a vector. Explanatory variables typically include origin and destination characteristics as well as distance between each region and all other regions. Our extension introduces latent spatial effects parameters structured to follow a spatial autoregressive process. Individual effects parameters are included in the model to reflect latent or unobservable influences at work that are unique to each region treated as an origin and destination. That is, we estimate 2 n individual effects parameters using the sample of N = n 2 observations. We illustrate the method using a sample of commodity flows between 18 Spanish regions during the 2002 period.
Origin of aromatase inhibitory activity via proteochemometric modeling.
Simeon, Saw; Spjuth, Ola; Lapins, Maris; Nabu, Sunanta; Anuwongcharoen, Nuttapat; Prachayasittikul, Virapong; Wikberg, Jarl E S; Nantasenamat, Chanin
2016-01-01
Aromatase, the rate-limiting enzyme that catalyzes the conversion of androgen to estrogen, plays an essential role in the development of estrogen-dependent breast cancer. Side effects due to aromatase inhibitors (AIs) necessitate the pursuit of novel inhibitor candidates with high selectivity, lower toxicity and increased potency. Designing a novel therapeutic agent against aromatase could be achieved computationally by means of ligand-based and structure-based methods. For over a decade, we have utilized both approaches to design potential AIs for which quantitative structure-activity relationships and molecular docking were used to explore inhibitory mechanisms of AIs towards aromatase. However, such approaches do not consider the effects that aromatase variants have on different AIs. In this study, proteochemometrics modeling was applied to analyze the interaction space between AIs and aromatase variants as a function of their substructural and amino acid features. Good predictive performance was achieved, as rigorously verified by 10-fold cross-validation, external validation, leave-one-compound-out cross-validation, leave-one-protein-out cross-validation and Y-scrambling tests. The investigations presented herein provide important insights into the mechanisms of aromatase inhibitory activity that could aid in the design of novel potent AIs as breast cancer therapeutic agents.
Early Paleozoic tectonics of Asia: A preliminary full-plate model
Domeier, Mat
2017-04-01
One of the largest and longest evolving orogens on Earth, the Central Asian Orogenic Belt (CAOB; alt. the Altaids) is as endlessly fascinating as it is astonishingly complex. By the slow grind of tectonics, the CAOB was forged over hundreds of millions of years, with a spectacular climax during the late Paleozoic and early Mesozoic, when a series of terrane collisions first melded a mosaic of island arcs and continental blocks into a colossal landmass that we now know as Asia. Unsurprisingly, that dynamic late Paleozoic to early Mesozoic interval has garnered tremendous interest, stimulated a great wealth of studies, and instigated captivating ongoing debates. But what set the stage for this action-packed display? Here I report on an ongoing initiative to weave together a self-consistent, full-plate tectonic model of the building blocks of Asia in the early Paleozoic ( 500-400 Ma), this will provide a testable and freely-available geodynamic framework for early CAOB genesis that can focus new work and foster new insights into the nature and evolution of Asia.
Full acoustic and thermal characterization of HIFU field in the presence of a ribcage model
Cao, Rui; Le, Nhan; Nabi, Ghulam; Huang, Zhihong
2017-03-01
In the treatment of abdominal organs using high intensity focused ultrasound (HIFU), the patient's ribs are in the pathway of the HIFU beams which could result in acoustic distortion, occasional skin burns and insufficient energy delivered to the target organs. To provide full characterization of HIFU field with the influence of ribcage, the ribcage phantom reconstructed from a patient's CT images was created by tissue mimicking materials and its effect on acoustic field was characterized. The effect of the ribcage on acoustic field has been provided in acoustic pressure distribution, acoustic power and focal temperature. Measurement result shows focus splitting with one main focus and two secondary intensity maxima. With the presence of ribcage phantom, the acoustic pressure was reduced by 48.3% and another two peak values were observed near the main focus, reduced by 65.0% and 71.7% respectively. The acoustic power was decreased by 47.5% to 52.5%. With these characterization results, the form of the focus, the acoustic power, acoustic pressure and temperature rise are provided before the transcostal HIFU treatment, which are significant to determine the energy delivery dose. In conclusion, this ribcage model and characterization technique will be useful for the further study in the abdominal HIFU treatment.
Radiative capture reaction for $^{17}$Ne formation within a full three-body model
Casal, J; de Diego, R; Arias, J M; Rodríguez-Gallardo, M
2016-01-01
Background: The breakout from the hot CNO cycles can trigger the rp-process in type I X-ray bursts. In this environment, a competition between $^{15}\\text{O}(\\alpha,\\gamma){^{19}\\text{Ne}}$ and the two-proton capture reaction $^{15}\\text{O}(2p,\\gamma){^{17}\\text{Ne}}$ is expected. Purpose: Determine the three-body radiative capture reaction rate for ${^{17}\\text{Ne}}$ formation including sequential and direct, resonant and non-resonant contributions on an equal footing. Method: Two different discretization methods have been applied to generate $^{17}$Ne states in a full three-body model: the analytical transformed harmonic oscillator method and the hyperspherical adiabatic expansion method. The binary $p$--$^{15}$O interation has been adjusted to reproduce the known spectrum of the unbound $^{16}$F nucleus. The dominant E1 contributions to the $^{15}\\text{O}(2p,\\gamma){^{17}\\text{Ne}}$ reaction rate have been calculated from the inverse photodissociation process. Results: Three-body calculations provide a rel...
Mathematical modeling and full-scale shaking table tests for multi-curve buckling restrained braces
Institute of Scientific and Technical Information of China (English)
C. S. Tsai; Yungchang Lin; Wenshin Chen; H. C. Su
2009-01-01
Buckling restrained braces (BRBs) have been widely applied in seismic mitigation since they were introduced in the 1970s. However, traditional BRBs have several disadvantages caused by using a steel tube to envelope the mortar to prevent the core plate from buckling, such as: complex interfaces between the materials used, uncertain precision, and time consumption during the manufacturing processes. In this study, a new device called the multi-curve buckling restrained brace (MC-BRB) is proposed to overcome these disadvantages. The new device consists of a core plate with multiple neck portions assembled to form multiple energy dissipation segments, and the enlarged segment, lateral support elements and constraining elements to prevent the BRB from buckling. The enlarged segment located in the middle of the core plate can be welded to the lateral support and constraining elements to increase buckling resistance and to prevent them from sliding during earthquakes. Component tests and a series of shaking table tests on a full-scale steel structure equipped with MC-BRBs were carried out to investigate the behavior and capability of this new BRB design for seismic mitigation. The experimental results illustrate that the MC-BRB possesses a stable mechanical behavior under cyclic loadings and provides good protection to structures during earthquakes. Also, a mathematical model has been developed to simulate the mechanical characteristics of BRBs.
Unifying quantum heat transfer in a nonequilibrium spin-boson model with full counting statistics
Wang, Chen; Ren, Jie; Cao, Jianshu
2017-02-01
To study the full counting statistics of quantum heat transfer in a driven nonequilibrium spin-boson model, we develop a generalized nonequilibrium polaron-transformed Redfield equation with an auxiliary counting field. This enables us to study the impact of qubit-bath coupling ranging from weak to strong regimes. Without external modulations, we observe maximal values of both steady-state heat flux and noise power in moderate coupling regimes, below which we find that these two transport quantities are enhanced by the finite-qubit-energy bias. With external modulations, the geometric-phase-induced heat flux shows a monotonic decrease upon increasing the qubit-bath coupling at zero qubit energy bias (without bias). While under the finite-qubit-energy bias (with bias), the geometric-phase-induced heat flux exhibits an interesting reversal behavior in the strong coupling regime. Our results unify the seemingly contradictory results in weak and strong qubit-bath coupling regimes and provide detailed dissections for the quantum fluctuation of nonequilibrium heat transfer.
Velay, V.; Robert, L.; Schmidt, F.; Hmida, S.; Vallet, T.
2007-04-01
Biaxial properties of materials (polymer or steel) used in many industrial processes are often difficult to measure. However, these properties are useful for the numerical simulations of plastic-processing operations like blow moulding or thermoforming for polymers and superplastic forming or single point incremental forming for steels. Today, Optical Full Field Measurements (OFFM) are promising tools for experimental analysis of materials. Indeed, they are able to provide a very large amount of data (displacement or strain) spatially distributed. In this paper, a mixed numerical and experimental investigation is proposed in order to identify multi-axial constitutive behaviour models. The procedure is applied on two different materials commonly used in forming processes: polymer (rubber in this first approach) and steel. Experimental tests are performed on various rubber and steel structural specimens (notched and open-hole plate samples) in order to generate heterogeneous displacement field. Two different behaviour models are considered. On the one hand, a Money-Rivlin hyperelastic law is investigated to describe the high levels of strain induced in tensile test performed on a rubber open-hole specimen. On the other hand, Ramberg-Osgood law allows to reproduce elasto-plastic behaviour of steel on a specimen that induces heterogeneous strain fields. Each parameter identification is based on a same Finite Element Model Updated (FEMU) procedure which consists in comparing results provided by the numerical simulation (ABAQUS™) with full field measurements obtained by the DISC (Digital Image Stereo-Correlation) technique (Vic-3D®).
Carmona Benitez, R.B.; Lodewijks, G.
2008-01-01
The deregulation and liberalization of the air transportation industry have developed three main passenger business models: full service carriers, low-cost carriers, and charter airlines. Deregulation removed regulated fares and routes increasing competition and yields. Airlines business models main
Carmona Benitez, R.B.; Lodewijks, G.
2008-01-01
The deregulation and liberalization of the air transportation industry have developed three main passenger business models: full service carriers, low-cost carriers, and charter airlines. Deregulation removed regulated fares and routes increasing competition and yields. Airlines business models main
Introductory biology students' conceptual models and explanations of the origin of variation.
Speth, Elena Bray; Shaw, Neil; Momsen, Jennifer; Reinagel, Adam; Le, Paul; Taqieddin, Ranya; Long, Tammy
2014-01-01
Mutation is the key molecular mechanism generating phenotypic variation, which is the basis for evolution. In an introductory biology course, we used a model-based pedagogy that enabled students to integrate their understanding of genetics and evolution within multiple case studies. We used student-generated conceptual models to assess understanding of the origin of variation. By midterm, only a small percentage of students articulated complete and accurate representations of the origin of variation in their models. Targeted feedback was offered through activities requiring students to critically evaluate peers' models. At semester's end, a substantial proportion of students significantly improved their representation of how variation arises (though one-third still did not include mutation in their models). Students' written explanations of the origin of variation were mostly consistent with their models, although less effective than models in conveying mechanistic reasoning. This study contributes evidence that articulating the genetic origin of variation is particularly challenging for learners and may require multiple cycles of instruction, assessment, and feedback. To support meaningful learning of the origin of variation, we advocate instruction that explicitly integrates multiple scales of biological organization, assessment that promotes and reveals mechanistic and causal reasoning, and practice with explanatory models with formative feedback.
Directory of Open Access Journals (Sweden)
Seki Motoaki
2008-11-01
Full Text Available Abstract Background Thellungiella halophila (also known as Thellungiella salsuginea is a model halophyte with a small plant size, short life cycle, and small genome. It easily undergoes genetic transformation by the floral dipping method used with its close relative, Arabidopsis thaliana. Thellungiella genes exhibit high sequence identity (approximately 90% at the cDNA level with Arabidopsis genes. Furthermore, Thellungiella not only shows tolerance to extreme salinity stress, but also to chilling, freezing, and ozone stress, supporting the use of Thellungiella as a good genomic resource in studies of abiotic stress tolerance. Results We constructed a full-length enriched Thellungiella (Shan Dong ecotype cDNA library from various tissues and whole plants subjected to environmental stresses, including high salinity, chilling, freezing, and abscisic acid treatment. We randomly selected about 20 000 clones and sequenced them from both ends to obtain a total of 35 171 sequences. CAP3 software was used to assemble the sequences and cluster them into 9569 nonredundant cDNA groups. We named these cDNAs "RTFL" (RIKEN Thellungiella Full-Length cDNAs. Information on functional domains and Gene Ontology (GO terms for the RTFL cDNAs were obtained using InterPro. The 8289 genes assigned to InterPro IDs were classified according to the GO terms using Plant GO Slim. Categorical comparison between the whole Arabidopsis genome and Thellungiella genes showing low identity to Arabidopsis genes revealed that the population of Thellungiella transport genes is approximately 1.5 times the size of the corresponding Arabidopsis genes. This suggests that these genes regulate a unique ion transportation system in Thellungiella. Conclusion As the number of Thellungiella halophila (Thellungiella salsuginea expressed sequence tags (ESTs was 9388 in July 2008, the number of ESTs has increased to approximately four times the original value as a result of this effort. Our
Modeling of multi-band drift in nanowires using a full band Monte Carlo simulation
Hathwar, Raghuraj; Saraniti, Marco; Goodnick, Stephen M.
2016-07-01
We report on a new numerical approach for multi-band drift within the context of full band Monte Carlo (FBMC) simulation and apply this to Si and InAs nanowires. The approach is based on the solution of the Krieger and Iafrate (KI) equations [J. B. Krieger and G. J. Iafrate, Phys. Rev. B 33, 5494 (1986)], which gives the probability of carriers undergoing interband transitions subject to an applied electric field. The KI equations are based on the solution of the time-dependent Schrödinger equation, and previous solutions of these equations have used Runge-Kutta (RK) methods to numerically solve the KI equations. This approach made the solution of the KI equations numerically expensive and was therefore only applied to a small part of the Brillouin zone (BZ). Here we discuss an alternate approach to the solution of the KI equations using the Magnus expansion (also known as "exponential perturbation theory"). This method is more accurate than the RK method as the solution lies on the exponential map and shares important qualitative properties with the exact solution such as the preservation of the unitary character of the time evolution operator. The solution of the KI equations is then incorporated through a modified FBMC free-flight drift routine and applied throughout the nanowire BZ. The importance of the multi-band drift model is then demonstrated for the case of Si and InAs nanowires by simulating a uniform field FBMC and analyzing the average carrier energies and carrier populations under high electric fields. Numerical simulations show that the average energy of the carriers under high electric field is significantly higher when multi-band drift is taken into consideration, due to the interband transitions allowing carriers to achieve higher energies.
Modeling basin- and plume-scale processes of CO2 storage for full-scale deployment
Energy Technology Data Exchange (ETDEWEB)
Zhou, Q.; Birkholzer, J.T.; Mehnert, E.; Lin, Y.-F.; Zhang, K.
2009-08-15
Integrated modeling of basin- and plume-scale processes induced by full-scale deployment of CO{sub 2} storage was applied to the Mt. Simon Aquifer in the Illinois Basin. A three-dimensional mesh was generated with local refinement around 20 injection sites, with approximately 30 km spacing. A total annual injection rate of 100 Mt CO{sub 2} over 50 years was used. The CO{sub 2}-brine flow at the plume scale and the single-phase flow at the basin scale were simulated. Simulation results show the overall shape of a CO{sub 2} plume consisting of a typical gravity-override subplume in the bottom injection zone of high injectivity and a pyramid-shaped subplume in the overlying multilayered Mt. Simon, indicating the important role of a secondary seal with relatively low-permeability and high-entry capillary pressure. The secondary-seal effect is manifested by retarded upward CO{sub 2} migration as a result of multiple secondary seals, coupled with lateral preferential CO{sub 2} viscous fingering through high-permeability layers. The plume width varies from 9.0 to 13.5 km at 200 years, indicating the slow CO{sub 2} migration and no plume interference between storage sites. On the basin scale, pressure perturbations propagate quickly away from injection centers, interfere after less than 1 year, and eventually reach basin margins. The simulated pressure buildup of 35 bar in the injection area is not expected to affect caprock geomechanical integrity. Moderate pressure buildup is observed in Mt. Simon in northern Illinois. However, its impact on groundwater resources is less than the hydraulic drawdown induced by long-term extensive pumping from overlying freshwater aquifers.
Two-dimensional finite-element modeling of periodical interdigitated full organic solar cells
Granero, P.; Balderrama, V. S.; Ferré-Borrull, J.; Pallarès, J.; Marsal, L. F.
2013-01-01
By means of finite-element numerical modeling, we analyze the influence of the nanostructured dissociation interface geometry on the behavior of interdigitated heterojunction full organic solar cells. A systematic analysis of light absorption, exciton diffusion, and carrier transport, all in the same numerical framework, is carried out to obtain their dependence on the interface geometrical parameters: pillar diameter and height, and nanostructure period. Cells are constituted of poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61. Results show that light absorption is maximum for pillar heights of 80 nm and 230 nm. However, due to the short exciton diffusion length of organic materials, the analysis of the exciton diffusion process reveals that the 80 nm thickness gives rise to a higher photocurrent, except for the smaller pillar diameters. In terms of efficiency, it has been observed that the charge carrier transport is weakly dependent on the geometric parameters of the nanostructured interface if compared with the exciton diffusion process. The optimal cell is a device with a pillar height of 80 nm, a structure period of 25 nm, and a ratio of the nanopillar diameter to the period of 0.75, with an efficiency 3.6 times higher than the best planar bilayer reference device. This structure is such that it reaches a compromise between having a high proportion of P3HT to increase light absorption but preserving a small pillar diameter and interpillar distance to ensure an extended exciton dissociation interface.
Origin of the Earth: A proposal of new model called ABEL
Directory of Open Access Journals (Sweden)
Shigenori Maruyama
2017-03-01
Full Text Available The Earth was born as a dry planet without atmosphere and ocean components at 4.56 Ga, with subsequent secondary accretion of bio-elements, such as carbon (C, hydrogen (H, oxygen (O, and nitrogen (N which peaked at 4.37–4.20 Ga. This two-step formation model of the Earth we refer to as the advent of bio-elements model (ABEL Model and the event of the advent of bio-elements (water component as ABEL Bombardment. It is clear that the solid Earth originated from enstatite chondrite-like dry material based on the similarity in oxygen isotopic composition and among other isotopes. On the other hand, Earth's water derives primarily from carbonaceous chondrite material based on the hydrogen isotopic ratio. We present our ABEL model to explain this enigma between solid Earth and water, as well as secondary accretion of oxidizing bio-elements, which became a precursor to initiate metabolism to emerge life on a highly reductive planet. If ABEL Bombardment had not occurred, life never would have emerged on the Earth. Therefore, ABEL Bombardment is one of the most important events for this planet to evolve into a habitable planet. The chronology of ABEL Bombardment is informed through previous researches of the late heavy bombardment and the late veneer model. ABEL Bombardment is considered to have occurred during 4.37–4.20 Ga, which is the concept to redefine the standard late heavy bombardment and the late veneer models. Also, ABEL Bombardment is the trigger of the transition from stagnant lid tectonics to plate tectonics on this planet because of the injection of volatiles into the initial dry Earth.
Evaluation of Iron Bioavailability in Caco-2 cell Culture Model: Modification of the Original Method
Directory of Open Access Journals (Sweden)
Bahareh Nikooyeh
2016-07-01
Full Text Available Background and Objectives: In the original in vitro method for evaluation of iron bioavailability using caco-2 cell model, ferritin formation by cells is considered as a functional indicator of both absorption and utilization of iron. However, as iron is measured in the tested material and then ferritin concentration is measured in caco-2 cell lysate, it is almost impossible to have a concrete measure of iron bioavailability because the percent of absorbable iron cannot be calculated by the concentration of iron in caco-2 cell lysate. To overcome this problem, the original method was modified by using ferrous sulfate tablet as a standard and also including blank well in the cell culture plate to subtract the baseline ferritin concentration from the ferritin concentration of other wells. Materials and Methods: To evaluate iron bioavailability in this model, one kind of Iranian traditional breads (Sangak was used. Standard curve was plotted using iron concentration and ferritin/protein ratio in the X and Y axes, respectively. Results: The standard curve showed a linear equation: Ferritin (ng/protein (mg = (5.96 × bread Fe+ 11.55, R2=0.989. Using this equation, the bioavailability of iron from the tested bread was 79.76 ± 11.5% of ferrous sulfate. Considering that the reported iron bioavailability from ferrous sulfate is about 10%, bioavailability of iron from the bread could be regarded 8%. Conclusions: This data can be potentially usable to adjust the amount of absorbable iron in the target population for fortification programs. Keywords: Iron, Bioavailability, Caco-2 cell
Shih, Chihhsiong
2005-01-01
Two efficient workflow are developed for the reconstruction of a 3D full color building model. One uses a point wise sensing device to sample an unknown object densely and attach color textures from a digital camera separately. The other uses an image based approach to reconstruct the model with color texture automatically attached. The point wise sensing device reconstructs the CAD model using a modified best view algorithm that collects the maximum number of construction faces in one view. The partial views of the point clouds data are then glued together using a common face between two consecutive views. Typical overlapping mesh removal and coarsening procedures are adapted to generate a unified 3D mesh shell structure. A post processing step is then taken to combine the digital image content from a separate camera with the 3D mesh shell surfaces. An indirect uv mapping procedure first divide the model faces into groups within which every face share the same normal direction. The corresponding images of these faces in a group is then adjusted using the uv map as a guidance. The final assembled image is then glued back to the 3D mesh to present a full colored building model. The result is a virtual building that can reflect the true dimension and surface material conditions of a real world campus building. The image based modeling procedure uses a commercial photogrammetry package to reconstruct the 3D model. A novel view planning algorithm is developed to guide the photos taking procedure. This algorithm successfully generate a minimum set of view angles. The set of pictures taken at these view angles can guarantee that each model face shows up at least in two of the pictures set and no more than three. The 3D model can then be reconstructed with minimum amount of labor spent in correlating picture pairs. The finished model is compared with the original object in both the topological and dimensional aspects. All the test cases show exact same topology and
Exploring the Full-Information Bifactor Model in Vertical Scaling with Construct Shift
Li, Ying; Lissitz, Robert W.
2012-01-01
To address the lack of attention to construct shift in item response theory (IRT) vertical scaling, a multigroup, bifactor model was proposed to model the common dimension for all grades and the grade-specific dimensions. Bifactor model estimation accuracy was evaluated through a simulation study with manipulated factors of percentage of common…
Modeling of EAST ICRF antenna performance using the full-wave code TORIC
Energy Technology Data Exchange (ETDEWEB)
Edlund, E. M., E-mail: eedlund@pppl.gov [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Bonoli, P. T.; Porkolab, M.; Wukitch, S. J. [MIT Plasma Science and Fusion Center, Cambridge, MA (United States)
2015-12-10
Access to advanced operating regimes in the EAST tokamak will require a combination of electron-cyclotron resonance heating (ECRH), neutral beam injection (NBI) and ion cyclotron range frequency heating (ICRF), with the addition of lower-hybrid current drive (LHCD) for current profile control. Prior experiments at the EAST tokamak facility have shown relatively weak response of the plasma temperature to application of ICRF heating, with typical coupled power about 2 MW out of 12 MW source. The launched spectrum, at n{sub φ} = 34 for 0-π -0-π phasing and 27 MHz, is largely inaccessible at line-averaged densities of approximately 2 × 10{sup 19} m{sup −3}. However, with variable antenna phasing and frequency, this system has considerable latitude to explore different heating schemes. To develop an ICRF actuator control model, we have used the full-wave code TORIC to explore the physics of ICRF wave propagation in EAST. The results presented from this study use a spectrum analysis using a superposition of n{sub φ} spanning −50 to +50. The low density regime typical of EAST plasmas results in a perpendicular wavelength comparable to the minor radius which results in global cavity resonance effects and eigenmode formation when the single-pass absorption is low. This behavior indicates that improved performance can be attained by lowering the peak of the k{sub ||} spectrum by using π/3 phasing of the 4-strap antenna. Based on prior studies conducted at Alcator C-Mod, this phasing is also expected to have the advantage of nearly divergence-free box currents, which should result in reduced levels of impurity production. Significant enhancements of the loading resistance may be achieved by using low k{sub ||} phasing and a combination of magnetic field and frequency to vary the location of the resonance and mode conversion regions. TORIC calculations indicate that the significant power may be channeled to the electrons and deuterium majority. We expect that
Properties of Closed-Loop Reference Models in Adaptive Control: Part I Full States Accessible
Gibson, Travis E; Lavretsky, Eugene
2012-01-01
This paper explores the properties of adaptive systems with closed-loop reference models. Historically, reference models in adaptive systems run open-loop in parallel with the plant and controller, using no information from the plant or controller to alter the trajectory of the reference system. Closed-loop reference models on the other hand use information from the plant to alter the reference trajectory. We show that closed-loop reference models have one more free design parameter as compared to their open-loop counterparts. Using the extra design freedom, we study closed--loop reference models and their impact on transient response and robustness in adaptive systems.
Zurfluh, Katrin; Klumpp, Jochen; Nüesch-Inderbinen, Magdalena; Stephan, Roger
2016-09-01
Here, we present the full sequences of three mcr-1-carrying plasmids isolated from extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli The plasmids belong to three different replicon types and are 34,640 bp, 209,401 bp, and 247,885 bp in size. We describe for the first time a composite transposon containing mcr-1 localized on a multidrug-resistant (MDR) IncHI2 plasmid harboring additional determinants of resistance to six different classes of antibiotics, including the ESBL gene blaCTX-M-1, and heavy metal resistance. Copyright © 2016, American Society for Microbiology. All Rights Reserved.
A Fovea Localization Scheme Using Vessel Origin-Based Parabolic Model
Directory of Open Access Journals (Sweden)
Chun-Yuan Yu
2014-09-01
Full Text Available At the center of the macula, fovea plays an important role in computer-aided diagnosis. To locate the fovea, this paper proposes a vessel origin (VO-based parabolic model, which takes the VO as the vertex of the parabola-like vasculature. Image processing steps are applied to accurately locate the fovea on retinal images. Firstly, morphological gradient and the circular Hough transform are used to find the optic disc. The structure of the vessel is then segmented with the line detector. Based on the characteristics of the VO, four features of VO are extracted, following the Bayesian classification procedure. Once the VO is identified, the VO-based parabolic model will locate the fovea. To find the fittest parabola and the symmetry axis of the retinal vessel, an Shift and Rotation (SR-Hough transform that combines the Hough transform with the shift and rotation of coordinates is presented. Two public databases of retinal images, DRIVE and STARE, are used to evaluate the proposed method. The experiment results show that the average Euclidean distances between the located fovea and the fovea marked by experts in two databases are 9.8 pixels and 30.7 pixels, respectively. The results are stronger than other methods and thus provide a better macular detection for further disease discovery.
EMG-to-force estimation with full-scale physiology based muscle model
Hayashibe, Mitsuhiro; Guiraud, David; Poignet, Philippe
2009-01-01
International audience; EMG-to-force estimation for voluntary muscle contraction has many applications in human-machine interaction, motion analysis, and rehabilitation robotics for prosthetic limbs or exoskeletons. EMG-based model can account for a subject's individual activation patterns to estimate muscle force. For the estimation, so-called Hill-type model has been used in most of the cases. It already has shown its promising performance, but it is still known as a phenomenological model ...
On the origin of crossover interference: A chromosome oscillatory movement (COM model
Directory of Open Access Journals (Sweden)
Hultén Maj A
2011-04-01
Full Text Available Abstract Background It is now nearly a century since it was first discovered that crossovers between homologous parental chromosomes, originating at the Prophase stage of Meiosis I, are not randomly placed. In fact, the number and distribution of crossovers are strictly regulated with crossovers/chiasmata formed in optimal positions along the length of individual chromosomes, facilitating regular chromosome segregation at the first meiotic division. In spite of much research addressing this question, the underlying mechanism(s for the phenomenon called crossover/chiasma interference is/are still unknown; and this constitutes an outstanding biological enigma. Results The Chromosome Oscillatory Movement (COM model for crossover/chiasma interference implies that, during Prophase of Meiosis I, oscillatory movements of the telomeres (attached to the nuclear membrane and the kinetochores (within the centromeres create waves along the length of chromosome pairs (bivalents so that crossing-over and chiasma formation is facilitated by the proximity of parental homologs induced at the nodal regions of the waves thus created. This model adequately explains the salient features of crossover/chiasma interference, where (1 there is normally at least one crossover/chiasma per bivalent, (2 the number is correlated to bivalent length, (3 the positions are dependent on the number per bivalent, (4 interference distances are on average longer over the centromere than along chromosome arms, and (5 there are significant changes in carriers of structural chromosome rearrangements. Conclusions The crossover/chiasma frequency distribution in humans and mice with normal karyotypes as well as in carriers of structural chromosome rearrangements are those expected on the COM model. Further studies are underway to analyze mechanical/mathematical aspects of this model for the origin of crossover/chiasma interference, using string replicas of the homologous chromosomes at the
Dynamic Modelling and Identification of Precipitation Reactions in Full-Scale WWTP
DEFF Research Database (Denmark)
Mbamba, Christian Kazadi; Tait, Stephan; Flores-Alsina, Xavier
Current process models used across the wastewater industry have inherent limitations due to limited description of physicochemical processes such as precipitation. As part of the overall effort towards more general and robust physicochemical models applicable to the broad range of problems, this ...
A full 3D time-dependent electromagnetic model for Roebel cables
DEFF Research Database (Denmark)
Rodriguez Zermeno, Victor Manuel; Grilli, Francesco; Sirois, Frederic
2013-01-01
current sharing among them. However, since Roebel cables have a true 3D structure and are made of several high aspect ratio coated conductors, modelling and simulation of their electromagnetic properties is very challenging. Therefore, a realistic model taking into account the actual layout of the cable...
Validation of Simulation Model for Full Scale Wave Simulator and Discrete Fuild Power PTO System
DEFF Research Database (Denmark)
Hansen, Anders Hedegaard; Pedersen, Henrik C.; Hansen, Rico Hjerm
2014-01-01
In controller development for large scale machinery a good simulation model may serve as a time and money saving factor as well as a safety precaution. Having good models enables the developer to design and test control strategies in a safe and possibly less time consuming environment...
Comparing a quasi-3D to a full 3D nearshore circulation model: SHORECIRC and ROMS
Haas, K.A.; Warner, J.C.
2009-01-01
Predictions of nearshore and surf zone processes are important for determining coastal circulation, impacts of storms, navigation, and recreational safety. Numerical modeling of these systems facilitates advancements in our understanding of coastal changes and can provide predictive capabilities for resource managers. There exists many nearshore coastal circulation models, however they are mostly limited or typically only applied as depth integrated models. SHORECIRC is an established surf zone circulation model that is quasi-3D to allow the effect of the variability in the vertical structure of the currents while maintaining the computational advantage of a 2DH model. Here we compare SHORECIRC to ROMS, a fully 3D ocean circulation model which now includes a three dimensional formulation for the wave-driven flows. We compare the models with three different test applications for: (i) spectral waves approaching a plane beach with an oblique angle of incidence; (ii) monochromatic waves driving longshore currents in a laboratory basin; and (iii) monochromatic waves on a barred beach with rip channels in a laboratory basin. Results identify that the models are very similar for the depth integrated flows and qualitatively consistent for the vertically varying components. The differences are primarily the result of the vertically varying radiation stress utilized by ROMS and the utilization of long wave theory for the radiation stress formulation in vertical varying momentum balance by SHORECIRC. The quasi-3D model is faster, however the applicability of the fully 3D model allows it to extend over a broader range of processes, temporal, and spatial scales. ?? 2008 Elsevier Ltd.
Kopelman, Yael; Siersema, Peter D.; Nir, Yael; Szold, Amir; Bapaye, Amol; Segol, Ori; Willenz, Ehud P.; Lelcuk, Shlomo; Geller, Alexander; Kopelman, Doron
2009-01-01
Background: Performing a full-thickness intestinal wall resection Of a sessile polyp located on the mesenteric side with a compression clip may lead to compression of mesenteric vessels. The application of such a clip may therefore cause a compromised blood supply in the particular bowel segment, le
Directory of Open Access Journals (Sweden)
Zsolt Pónya
2014-12-01
Full Text Available During in vitro fertilization of wheat (Triticum aestivum, L. in egg cells isolated at various developmental stages, changes in cytosolic free calcium ([Ca2+]cyt were observed. The dynamics of [Ca2+]cyt elevation varied, reflecting the difference in the developmental stage of the eggs used. [Ca2+]cyt oscillation was exclusively observed in fertile, mature egg cells fused with the sperm cell. To determine how [Ca2+]cyt oscillation in mature egg cells is generated, egg cells were incubated in thapsigargin, which proved to be a specific inhibitor of the endoplasmic reticulum (ER Ca2+-ATPase in wheat egg cells. In unfertilized egg cells, the addition of thapsigargin caused an abrupt transient increase in [Ca2+]cyt in the absence of extracellular Ca2+, suggesting that an influx pathway for Ca2+ is activated by thapsigargin. The [Ca2+]cyt oscillation seemed to require the filling of an intracellular calcium store for the onset of which, calcium influx through the plasma membrane appeared essential. This was demonstrated by omitting extracellular calcium from (or adding GdCl3 to the fusion medium, which prevented [Ca2+]cyt oscillation in mature egg cells fused with the sperm. Combined, these data permit the hypothesis that the first sperm-induced transient increase in [Ca2+]cyt depletes an intracellular Ca2+ store, triggering an increase in plasma membrane Ca2+ permeability, and this enhanced Ca2+ influx results in [Ca2+]cyt oscillation.
Trojan War displayed as a full annihilation-diffusion-reaction model
Flores, J. C.
2017-02-01
The diffusive pair annihilation model with embedded topological domains and archaeological data is applied in an analysis of the hypothetical Trojan-Greek war during the late Bronze Age. Estimations of parameter are explicitly made for critical dynamics of the model. In particular, the 8-metre walls of Troy could be viewed as the effective shield that provided the technological difference between the two armies. Suggestively, the numbers in The Iliad are quite sound, being in accord with Lanchester's laws of warfare.
A full model for simulation of electrochemical cells including complex behavior
Esperilla, J. J.; Félez, J.; Romero, G.; Carretero, A.
This communication presents a model of electrochemical cells developed in order to simulate their electrical, chemical and thermal behavior showing the differences when thermal effects are or not considered in the charge-discharge process. The work presented here has been applied to the particular case of the Pb,PbSO 4|H 2SO 4 (aq)|PbO 2,Pb cell, which forms the basis of the lead-acid batteries so widely used in the automotive industry and as traction batteries in electric or hybrid vehicles. Each half-cell is considered independently in the model. For each half-cell, in addition to the main electrode reaction, a secondary reaction is considered: the hydrogen evolution reaction in the negative electrode and the oxygen evolution reaction in the positive. The equilibrium potential is calculated with the Nernst equation, in which the activity coefficients are fitted to an exponential function using experimental data. On the other hand, the two main mechanisms that produce the overpotential are considered, that is the activation or charge transfer and the diffusion mechanisms. First, an isothermal model has been studied in order to show the behavior of the main phenomena. A more complex model has also been studied including thermal behavior. This model is very useful in the case of traction batteries in electric and hybrid vehicles where high current intensities appear. Some simulation results are also presented in order to show the accuracy of the proposed models.
Full-Thickness Thermal Injury Delays Wound Closure in a Murine Model
2015-01-01
fibronectin, and periostin during the remodeling phase of tissue repair.7–10 CLINICAL PROBLEM ADDRESSED Current strategies to optimize the outcome...The control represents normal collagen architectures on POD 0, while both contact and scald burn groups demonstrated full-thickness burn marked by...vs. 76.78% early interval excision, p =0.08) (Fig. 3). Burn injury retards wound re-epithelialization, closure, and remodeling Wound histology
Prediction model of gas explosion overpressure in full-scale coal mine blind roadway
Energy Technology Data Exchange (ETDEWEB)
Yun-Feng Liang; Xin-Quan Zhou; Jiu-Ling Zhang; Shao Shao [China University of Mining and Technology (Beijing), Beijing (China). State Key Laboratory of Coal Resources and Safe Mining
2009-01-15
On the basis of the TNT equivalency method and by analysing data from gas explosion experiments, a new prediction method was put forward to estimate the attenuation of explosion overpressure in a full-scale coal mine blind roadway and its validity was testified in three cases. The results show that there is good agreement between the calculated and experimental data. 8 refs., 2 figs.
Defining an equilibrium state in global full-f gyrokinetic models
Dif-Pradalier, Guilhem; Grandgirard, V; Sarazin, Y.; ,; ,; (:unav); Ghendrih, Philippe
2008-01-01
International audience; This paper tackles the delicate choice of the initial distribution function in full-f gyrokinetic codes such as GYSELA 5D, aiming at predicting the turbulent transport level in low collisional tokamak plasmas. It is found, both analytically and numerically, that a Maxwellian distribution function with constant profiles on magnetic flux surfaces leads to the fast generation of a large scale electric field. Such a field opposes the up–down charge separation governed by t...
Energy Technology Data Exchange (ETDEWEB)
Protsenko, K.; Badrzadeh, B. [Vestas Technology R and D, Aarhus (Denmark); Mayer, P.F. [Vestas Technology R and D, Singapore (Singapore); Luo, Z. [Vestas Americas, Houston, TX (United States)
2011-07-01
This paper presents the application of a real-time digital simulation program for wind turbine modeling of a doubly-fed induction generator (type 3) and a fully-converted permanent magnet synchronous generator (type 4). Vestas type 3 and type 4,3 MW turbines are taken as representative for the two turbine types, respectively. The paper begins with an overview of the hardware details used for the simulation studies, outlines the assumptions applied to derive the models, and highlights the limitations imposed by the use of a real time digital simulation program. The implementation of both types of turbine models is then discussed. The validation of both models against electromagnetic time domain simulation results obtained from PSCAD is shown. The validation test performed is the evaluation of low voltage ride through capability of the turbine. Results obtained from the real time digital simulation provide a good match with the PSCAD simulation results, which have in turn been validated against field measurements. This gives confidence in the future application of such real time models, for example in wind power plant protection relay coordination. (orig.)
Directory of Open Access Journals (Sweden)
Soheila Yadollah-Damavandi
2015-01-01
Full Text Available Delayed wound healing process is one of the most important concerns in diabetes. Healing of wounds has four phases, namely, hemostasis, inflammation, proliferation, and remodeling. For a successful repair, all four factors must occur properly. Hence, we aimed to evaluate the healing effects of Hypericum perforatum (HP on full-thickness diabetic skin wounds by using stereological methods. Forty-eight female diabetic rats were randomly divided into four groups (n=12: gel base treated group, HP 5% gel treated group, HP 10% gel treated group, and the control group which received no treatment. A circular 1 cm2 full-thickness wound was created on the animal’s neck and wound area was measured every three days. After sacrificing the animals, skin samples were fixed and prepared for stereological evaluations. Based on the results, HP treated group showed faster wound closure rate in comparison with control and vehicle groups (P<0.05. In addition, numerical density of fibroblasts, volume density of collagen bundles, and mean diameter and volume densities of the vessels in HP group were significantly higher than control and vehicle groups. The results of this study showed that HP has the ability to improve tissue regeneration by enhancing fibroblast proliferation, collagen bundle synthesis, and revascularization.
Poghosyan, Lusine; Boyd, Donald R; Clarke, Sean P
2016-01-01
Nurse practitioners (NPs), if utilized to their optimal potential, could play a key role in meeting the growing demand for primary care. The purpose of this study was to propose a comprehensive model for maximizing NP contributions to primary care which includes the factors affecting NP care and patient outcomes and explains their interrelated impact. We synthesized the results of the published literature to develop a model, which emphasizes NP scope of practice regulations, institutional policies, NP practice environment, and NP workforce outcomes as determinants of NP care and patient outcomes. Our model provides a framework to help explain how variations in scope of practice regulations at the state-level and institutional policies within organizations directly and indirectly influence the practice environment of NPs, NP workforce outcomes, and patient care and outcomes. Aligning policy change, organizational innovations, and future research are critical to NP optimal utilization and patient care and outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.
Mathematical modelling of full scale combustion in front wall fired boiler of EDP
Energy Technology Data Exchange (ETDEWEB)
Azevedo, J.L.T.; Coelho, L.M.R.; Carvalho, M.G. [Instituto Superior Tecnico, Lisbon (Portugal)
1998-12-31
Numerical modelling of pulverised coal combustion is applied to simulate front wall fired utility boilers to analyse the influence of air staging (using rows of burners out of service BOOS) or combined fuel and air staging (reburning). The NO{sub x} post processor of an existing numerical model is modified to consider these conditions and calculations are applied to two utility boilers. For the case of using BOOS the model indicates NO{sub x} reductions from 5 to 12% while for reburning the NO{sub x} emissions resulting from coal are reduced by 28%. The analysis of the results address besides the NO{sub x} emissions the amount of carbon in ash and the heat flux distribution in the boiler walls and superheater panels. 22 refs., 13 figs., 7 tabs.
Modelling of coal combustion enhanced through plasma-fuel systems in full-scale boilers
Energy Technology Data Exchange (ETDEWEB)
A.S. Askarova; Z. Jankoski; E.I. Karpenko; E.I. Lavrischeva; F.C. Lockwood; V.E. Messerle; A.B. Ustimenko [al-Farabi Kazakh National University, Almaty (Kazakhstan). Department of Physics
2005-07-01
Plasma activation promotes more effective and environmental friendly low-rank coal combustion. This work presents numerical modelling results of plasma thermochemical preparation of pulverized coal for ignition and combustion in the furnace of a utility boiler. Two kinetic mathematical models were used in the investigation of the processes of air-fuel mixture plasma activation, ignition and combustion. A 1D kinetic code, PLASMA-COAL, calculates the concentrations of species, temperatures and velocities of treated coal-air mixtures in a burner incorporating a plasma source. It gives initial data for 3D-modeling of power boilers furnaces by the code FLOREAN. A comprehensive image of plasma activated coal combustion processes in a furnace of pulverised coal fired boiler was obtained. The advantages of the plasma technology are clearly demonstrated. 15 refs., 6 figs., 4 tabs.
Sinha, Sanjay; Iyer, Dharini; Granata, Alessandra
2014-06-01
Vascular smooth muscle cells (SMCs) arise from multiple origins during development, raising the possibility that differences in embryological origins between SMCs could contribute to site-specific localization of vascular diseases. In this review, we first examine the developmental pathways and embryological origins of vascular SMCs and then discuss in vitro strategies for deriving SMCs from human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). We then review in detail the potential for vascular disease modeling using iPSC-derived SMCs and consider the pathological implications of heterogeneous embryonic origins. Finally, we touch upon the role of human ESC-derived SMCs in therapeutic revascularization and the challenges remaining before regenerative medicine using ESC- or iPSC-derived cells comes of age.
Full System Model of Magnetron Sputter Chamber - Proof-of-Principle Study
Energy Technology Data Exchange (ETDEWEB)
Walton, C; Gilmer, G; Zepeda-Ruiz, L; Wemhoff, A; Barbee, T
2007-05-04
The lack of detailed knowledge of internal process conditions remains a key challenge in magnetron sputtering, both for chamber design and for process development. Fundamental information such as the pressure and temperature distribution of the sputter gas, and the energies and arrival angles of the sputtered atoms and other energetic species is often missing, or is only estimated from general formulas. However, open-source or low-cost tools are available for modeling most steps of the sputter process, which can give more accurate and complete data than textbook estimates, using only desktop computations. To get a better understanding of magnetron sputtering, we have collected existing models for the 5 major process steps: the input and distribution of the neutral background gas using Direct Simulation Monte Carlo (DSMC), dynamics of the plasma using Particle In Cell-Monte Carlo Collision (PIC-MCC), impact of ions on the target using molecular dynamics (MD), transport of sputtered atoms to the substrate using DSMC, and growth of the film using hybrid Kinetic Monte Carlo (KMC) and MD methods. Models have been tested against experimental measurements. For example, gas rarefaction as observed by Rossnagel and others has been reproduced, and it is associated with a local pressure increase of {approx}50% which may strongly influence film properties such as stress. Results on energies and arrival angles of sputtered atoms and reflected gas neutrals are applied to the Kinetic Monte Carlo simulation of film growth. Model results and applications to growth of dense Cu and Be films are presented.
Modeling and control of isolated full bridge boost DC-DC converter implemented in FPGA
DEFF Research Database (Denmark)
Taeed, Fazel; Nymand, M.
2013-01-01
design are discussed. In the next step a digital PI controller is designed and implemented in a FPGA to control the output voltage. Using the injection transformer method the open loop transfer function in closed loop is measured and modeling results are verified by experimental results. © 2013 IEEE....
Principles of 5D modeling, full integration of 3D space, time and scale
Van Oosterom, P.; Stoter, J.
2012-01-01
This paper proposes an approach for data modelling in five dimensions. Apart from three dimensions for geometrical representation and a fourth dimension for time, we identify scale as fifth dimensional characteristic. Considering scale as an extra dimension of geographic information, fully integrate
Full vehicle ABS braking using the SWIFT rigid ring tyre model
Jansen, S.; Pauwelussen, J.P.; Gootjes, L.; Schröder, C.
2000-01-01
In recent years, at the Delft University of Technology and TNO Automotive and in conjuction with an industrial consortium, a pragmatic tyre model has been developed going by the name SWIFT, which is geared to the analysis of tyre oscillations and its effects on vehicle behaviour. The SWIFt tyre mode
Determinants of Students' Outcome: A Full-Fledged Structural Equation Modelling Approach
Musah, Mohammed Borhandden; Ali, Hairuddin Bin Mohd; Al-Hudawi, Shafeeq Hussain Vazhathodi; Tahir, Lokman Mohd; Daud, Khadijah Binti; Hamdan, Abdul Rahim
2015-01-01
The vibrant demand for academic excellence in the twenty-first century has brought diverse determinants of students' outcome into play. However, few studies have validated the instruments and examined the mediating effect between exogenous and endogenous variables of the student outcome model. This study, therefore, investigates the psychometric…
Multi-Observation Continuous Density Hidden Markov Models for Anomaly Detection in Full Motion Video
2012-06-01
Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) are used to...distribution analysis for scoring Log-likelihood • Automatically select MOCDHMM model via Akaike Information Criteria (AIC) or Bayesian Information Criteria...limited to any particular graphical structure. For example, Xiang uses Bayesian Information Criterion (BICr) and Completed Likelihood Akaike’s Information
Determinants of Students' Outcome: A Full-Fledged Structural Equation Modelling Approach
Musah, Mohammed Borhandden; Ali, Hairuddin Bin Mohd; Al-Hudawi, Shafeeq Hussain Vazhathodi; Tahir, Lokman Mohd; Daud, Khadijah Binti; Hamdan, Abdul Rahim
2015-01-01
The vibrant demand for academic excellence in the twenty-first century has brought diverse determinants of students' outcome into play. However, few studies have validated the instruments and examined the mediating effect between exogenous and endogenous variables of the student outcome model. This study, therefore, investigates the psychometric…
A study of Forbush Decreases with a full 3-D cosmic ray modulation model
Luo, Xi; Zhang, Ming; Potgieter, Marius
2016-07-01
We have constructed a 3-D numerical model for studying Forbush Decreases (FDs) in the global heliosphere. It incorporates 3-D propagation barriers, with enhanced cooling inside, into a time-dependent Parker type modulation model using a Stochastic Differential Equation (SDE) approach. This numerical model simultaneously takes into account the effect of solar wind convection with associated adiabatic energy changes; gradient, curvature and current sheet drifts; as well as parallel and perpendicular diffusion. This state-of-the-art numerical model enables us to find and study some new 3-D features for FD type events: 1. The cosmic ray intensity at Earth varies depending on the relative location of the Earth to the current sheet, and is reflected also in the amplitude of the FDs. The local modulation conditions, at a given observational point, determine the total amplitude. 2. The radial, latitudinal and longitudinal extent of a diffusion barrier significantly affects the amplitude of a FD. 3. The recovery time of a FD, at a given observational location, is determined by the modulation conditions which the corresponding propagation barrier encounters as it moves outwards in the heliosphere.
Directory of Open Access Journals (Sweden)
A. Taravat
2013-09-01
Full Text Available As a major aspect of marine pollution, oil release into the sea has serious biological and environmental impacts. Among remote sensing systems (which is a tool that offers a non-destructive investigation method, synthetic aperture radar (SAR can provide valuable synoptic information about the position and size of the oil spill due to its wide area coverage and day/night, and all-weather capabilities. In this paper we present a new automated method for oil-spill monitoring. A new approach is based on the combination of Weibull Multiplicative Model and machine learning techniques to differentiate between dark spots and the background. First, the filter created based on Weibull Multiplicative Model is applied to each sub-image. Second, the sub-image is segmented by two different neural networks techniques (Pulsed Coupled Neural Networks and Multilayer Perceptron Neural Networks. As the last step, a very simple filtering process is used to eliminate the false targets. The proposed approaches were tested on 20 ENVISAT and ERS2 images which contained dark spots. The same parameters were used in all tests. For the overall dataset, the average accuracies of 94.05 % and 95.20 % were obtained for PCNN and MLP methods, respectively. The average computational time for dark-spot detection with a 256 × 256 image in about 4 s for PCNN segmentation using IDL software which is the fastest one in this field at present. Our experimental results demonstrate that the proposed approach is very fast, robust and effective. The proposed approach can be applied to the future spaceborne SAR images.
Full activated sludge model no. 1 calibration experience at a medium-size WWTP in Mexico.
Fall, C; Loaiza-Navia, J; Esparza-Soto, M
2009-01-01
As part of the efforts done to introduce the practice of modeling in Latin America, this research carried out at the North-East WWTP of Monterrey represents the first comprehensive modeling case in Mexico. The main objective was to reproduce the organic carbon removal and sludge production rates of the plant, based on ASM1. Different intermediate studies were performed prior to the calibration of the model: influent characterization, tracer tests and hydraulics modeling, sludge settling tests and respirometry. Two fractionation methods (STOWA protocol and Influent-advisor) were compared, showing no equivalent patterns. A stepwise sequence of calibration was developed and successfully applied. The hydraulics of the reactors at the plant was reproduced by use of a series of 3 to 5 CSTRs. The waste and return activated sludge flowrates (Q(WAS) and Q(RAS)) were corrected based on the inorganic and total suspended solids mass balances. The Vesilind settling constants were measured (V(o) and r(hind)), while the flocculent zone settling parameter (r(floc)) was adjusted to calibrate the secondary clarifier. In ASM1, the adjusted parameters were the COD soluble inert fraction (frS(I)) and the particulate substrate fraction (FrX(S)). All other ASM1 parameters were kept at their default values. The steady-state calibrated model (in GPS-X) adequately described the quality of the effluent (carbon and nitrogen) as well as the sludge composition (M. Liquor and WAS). This case study provides voluntarily detailed data to allow its wide use for training and teaching purposes.
On the Origin of Grid Anisotropy in the Simulation of Dendrite Growth by a VFT Model
Djaraoui, Afaf; Nebti, Samia
2016-10-01
A virtual front tracking model, based on solute and heat diffusion in two dimensions, is chosen to capture the full microstructural behavior of dendritic solidification in a binary alloy. We use a simple method of calculation, easy to perform, with relatively high stable time step, to simulate the dendrite growth in an Al-8 wt pct Mg alloy for which no numerical simulation has been carried out in the past. Local equilibrium at the liquid solid interface and the buildup of solute ahead of the interface are solved, and the dendrite growth process is simulated in isothermal solidification conditions. We show that the artificial grid anisotropy originates from the four cell neighborhood method adopted for capturing the moving front. By a correct neighborhood configuration, a grid independent set of results and expected phenomena are reproduced for a free dendrite growing either aligned or inclined with the grid. The dendrite morphology and orientation, and the growth velocity are explored via physical simulation parameters such as undercooling and surface tension anisotropy.
Tests for, origins of, and corrections to non-Gaussian statistics. The dipole-flip model.
Schile, Addison J; Thompson, Ward H
2017-04-21
Linear response approximations are central to our understanding and simulations of nonequilibrium statistical mechanics. Despite the success of these approaches in predicting nonequilibrium dynamics, open questions remain. Laird and Thompson [J. Chem. Phys. 126, 211104 (2007)] previously formalized, in the context of solvation dynamics, the connection between the static linear-response approximation and the assumption of Gaussian statistics. The Gaussian statistics perspective is useful in understanding why linear response approximations are still accurate for perturbations much larger than thermal energies. In this paper, we use this approach to address three outstanding issues in the context of the "dipole-flip" model, which is known to exhibit nonlinear response. First, we demonstrate how non-Gaussian statistics can be predicted from purely equilibrium molecular dynamics (MD) simulations (i.e., without resort to a full nonequilibrium MD as is the current practice). Second, we show that the Gaussian statistics approximation may also be used to identify the physical origins of nonlinear response residing in a small number of coordinates. Third, we explore an approach for correcting the Gaussian statistics approximation for nonlinear response effects using the same equilibrium simulation. The results are discussed in the context of several other examples of nonlinear responses throughout the literature.
Yadollah-Damavandi, Soheila; Chavoshi-Nejad, Mehdi; Jangholi, Ehsan; Nekouyian, Noushin; Hosseini, Sahar; Seifaee, Amin; Rafiee, Shima; Karimi, Hossein; Ashkani-Esfahani, Soheil; Parsa, Yekta; Mohsenikia, Maryam
2015-01-01
Delayed wound healing process is one of the most important concerns in diabetes. Healing of wounds has four phases, namely, hemostasis, inflammation, proliferation, and remodeling. For a successful repair, all four factors must occur properly. Hence, we aimed to evaluate the healing effects of Hypericum perforatum (HP) on full-thickness diabetic skin wounds by using stereological methods. Forty-eight female diabetic rats were randomly divided into four groups (n = 12): gel base treated group, HP 5% gel treated group, HP 10% gel treated group, and the control group which received no treatment. A circular 1 cm(2) full-thickness wound was created on the animal's neck and wound area was measured every three days. After sacrificing the animals, skin samples were fixed and prepared for stereological evaluations. Based on the results, HP treated group showed faster wound closure rate in comparison with control and vehicle groups (P < 0.05). In addition, numerical density of fibroblasts, volume density of collagen bundles, and mean diameter and volume densities of the vessels in HP group were significantly higher than control and vehicle groups. The results of this study showed that HP has the ability to improve tissue regeneration by enhancing fibroblast proliferation, collagen bundle synthesis, and revascularization.
The Phenion (R) Full-Thickness Skin Model for Percutaneous Absorption Testing
2010-01-01
In recent years many efforts have been made to replace dermal toxicity testing of chemicals in the animal by in vitro assays. As a member of a German research consortium, we have previously contributed to the validation of an in vitro test protocol for percutaneous absorption studies on the basis of reconstructed human epidermis and both human and pig skin ex vivo. Aiming to assess the barrier properties of a newly developed reconstructed skin model, this protocol has now been transferred to ...
Energy Technology Data Exchange (ETDEWEB)
Cimpan, Emil
2004-09-15
This work is concerned with the development of a new on-line measuring technique to be used in measurements of the water concentration in a two component oil/water or three component (i.e. multiphase) oil/water/gas flow. The technique is based on using non-intrusive coil detectors and experiments were performed both statically (medium at rest) and dynamically (medium flowing through a flow rig). The various coil detectors were constructed with either one or two coils and specially designed electronics were used. The medium was composed by air, machine oil, and water having different conductivity values, i.e. seawater and salt water with various conductivities (salt concentrations) such as 1 S/m, 4.9 S/m and 9.3 S/m. The experimental measurements done with the different mixtures were further used to mathematically model the physical principle used in the technique. This new technique is based on measuring the coil impedance and signal frequency at the self-resonance frequency of the coil to determine the water concentration in the mix. By using numerous coils it was found, experimentally, that generally both the coil impedance and the self-resonance frequency of the coil decreased as the medium conductivity increased. Both the impedance and the self-resonance frequency of the coil depended on the medium loss due to the induced eddy currents within the conductive media in the mixture, i.e. water. In order to detect relatively low values of the medium loss, the self-resonance frequency of the coil and also of the magnetic field penetrating the media should be relatively high (within the MHz range and higher). Therefore, the technique was called and referred to throughout the entire work as the high frequency magnetic field technique (HFMFT). To practically use the HFMFT, it was necessary to circumscribe an analytical frame to this technique. This was done by working out a mathematical model that relates the impedance and the self-resonance frequency of the coil to the
Defining an equilibrium state in global full-f gyrokinetic models
Energy Technology Data Exchange (ETDEWEB)
Dif-Pradalier, G.; Grandgirard, V.; Sarazin, Y.; Garbet, X.; Ghendrih, Ph. [CEA Cadarache, CEA/DSM/DRFC, EURATOM Assoc, F-13108 St Paul Les Durance, (France)
2008-07-01
This paper tackles the delicate choice of the initial distribution function in full-f gyrokinetic codes such as GYSELA 5D, aiming at predicting the turbulent transport level in low collisional tokamak plasmas. It is found, both analytically and numerically, that a Maxwellian distribution function with constant profiles on magnetic flux surfaces leads to the fast generation of a large scale electric field. Such a field opposes the up-down charge separation governed by the inhomogeneity of the equilibrium magnetic field. If large enough, the shearing rate induced by the resulting poloidal E * B velocity could efficiently reduce the plasma micro-instabilities which account for the development of the turbulence. Starting in the ab initio code GYSELA 5D from an equilibrium distribution function depending on motion invariants only is shown to cure such a problem. In this case, charge separation is counter-balanced by parallel flow, and the standard fluid force balance is recovered. (authors)
Defining an equilibrium state in global full-f gyrokinetic models
Dif-Pradalier, G.; Grandgirard, V.; Sarazin, Y.; Garbet, X.; Ghendrih, Ph.
2008-02-01
This paper tackles the delicate choice of the initial distribution function in full-f gyrokinetic codes such as G YSELA 5D, aiming at predicting the turbulent transport level in low collisional tokamak plasmas. It is found, both analytically and numerically, that a Maxwellian distribution function with constant profiles on magnetic flux surfaces leads to the fast generation of a large scale electric field. Such a field opposes the up-down charge separation governed by the inhomogeneity of the equilibrium magnetic field. If large enough, the shearing rate induced by the resulting poloidal E×B velocity could efficiently reduce the plasma micro-instabilities which account for the development of the turbulence. Starting in the ab initio code G YSELA 5 D from an equilibrium distribution function depending on motion invariants only is shown to cure such a problem. In this case, charge separation is counter-balanced by parallel flow, and the standard fluid force balance is recovered.
Unsteady interaction of a viscous fluid with an elastic shell modeled by full von Karman equations
Chueshov, Igor; Ryzhkova, Iryna
We study well-posedness and asymptotic dynamics of a coupled system consisting of linearized 3D Navier-Stokes equations in a bounded domain and a classical (nonlinear) full von Karman shallow shell equation that accounts for both transversal and lateral displacements on a flexible part of the boundary. We also take into account rotational inertia of filaments of the shell. Our main result shows that the problem generates a semiflow in an appropriate phase space. The regularity provided by viscous dissipation in the fluid allows us to consider simultaneously both cases of presence inertia in the lateral displacements and its absence. Our second result states the existence of a compact global attractor for this semiflow in the case of presence of (rotational) damping in the transversal component and a particular structure of external forces.
Unsteady interaction of a viscous fluid with an elastic shell modeled by full von Karman equations
Chueshov, Igor
2011-01-01
We study well-posedness and asymptotic dynamics of a coupled system consisting of linearized 3D Navier--Stokes equations in a bounded domain and a classical (nonlinear) full von Karman shallow shell equations that accounts for both transversal and lateral displacements on a flexible part of the boundary. We also take into account rotational inertia of filaments of the shell. Out main result shows that the problem generates a semiflow in an appropriate phase space. The regularity provided by viscous dissipation in the fluid allows us to consider simultaneously both cases of presence inertia in the lateral displacements and its absence. Our second result states the existence of a compact global attractor for this semiflow in the case of presence of (rotational) damping in the transversal component and a particular structure of external forces.
Nikitin, Andrei; Champion, Jean Paul; Tyuterev, Vladimir
2012-01-01
The MIRS software for the modeling of ro-vibrational spectra of polyatomic molecules was considerably extended and improved. The original version (Nikitin, et al. JQSRT, 2003, pp. 239--249) was especially designed for separate or simultaneous treatments of complex band systems of polyatomic molecules. It was set up in the frame of effective polyad models by using algorithms based on advanced group theory algebra to take full account of symmetry properties. It has been successfully used for predictions and data fitting (positions and intensities) of numerous spectra of symmetric and spherical top molecules within the vibration extrapolation scheme. The new version offers more advanced possibilities for spectra calculations and modeling by getting rid of several previous limitations particularly for the size of polyads and the number of tensors involved. It allows dealing with overlapping polyads and includes more efficient and faster algorithms for the calculation of coefficients related to molecular symmetry ...
Modeling tsunami of cosmogenic and landslide origin on the basis of Navier-Stokes equations
Kozelkov, Andrey; Kurkin, Andrey; Pelinovsky, Efim
2016-04-01
An approach to the modeling of the landslide and meteoritic origin tsunami, based on the Navier-Stokes equations for multiphase flows with a free surface, is presented. Description of the system's numerical integration, based on a fully implicit connection of velocity and pressure, is done. The connection of the continuity equation and the equations of conservation of momentum is based on account of the implicit terms of the pressure gradient and mass flow. Basic formulas for discretization of equations and the form of the coefficients, which are summarized in general associated matrix, are performed. Basic steps of the computational procedure are described. The results of proposed method's verification to the problems with experimental data (the problem of the dam collapse, a hydraulic jump and a falling of a box in the water) are presented. Results of the numerical modeling of possible hydrodynamic disturbances in the lake Chebarkul, Russia, caused by the fall of a meteorite in 2013, are presented. The numerical experiments are performed both with and without account of the lake's ice cover. Dimensions of the ice cover disruption are evaluated. Dimensions of the observable ice-hole in the place of the meteorite fall are shown to be in good agreement with the theoretical predictions and the preliminary estimations. In addition, results of the numerical investigation of the influence of angle of the body's entry into the water on the characteristics of the resulting waves in the near field are presented. Dimensions of the perturbation and the regularities of changes in the parameters of the source are studied. It is shown that the greatest change in characteristics of the source occurs most rapidly in the vicinity of the angle of incidence of 20 degrees to the horizontal. The source as a separate phase representing Newtonian fluid with its density and viscosity and the surface is separated from the water and air phase is used to simulate landslide. The results of
Full-wave model of D-region upward VLF coupling to whistlers in the plasmasphere
Jacobson, A. R.; Shao, X.; Lay, E. H.
2012-12-01
Atmospheric-lightning-to-plasmasphere VLF coupling via whistlers is key to understanding the problem of radiation-belt losses and the slot region. In the lowermost ionosphere, the "D-region" (roughly 60 - 100 km altitude), the coupling occurs between the VLF incident from the "vacuum" below, to the electron whistler capable of transiting upward through the E- and F-regions above. We have modified our successful and data-validated D-region VLF downward-reflection model to predict upward-coupled whistler waveforms recorded on topside satellites. The model has been run in production mode for predicting downward-reflected waveforms recorded at ground stations, but the model's internal calculation also fully describes the "penetrating" solution that merges into the oblique electron whistler. We have begun to test the model against VLF, three-dimensional electric-field recordings from the Vector Electric Field Instrument (VEFI) [Pfaff et al., 2010] on the C/NOFS satellite. VEFI's broadband recording and large on-board memory serendipitously provide an excellent platform for studying lightning whistlers in the plasmasphere. We have already demonstrated [Jacobson et al., 2011] that VEFI is superbly suited for testing transionospheric propagation, in conjunction with the World Wide Lightning Location Network (WWLLN; see www.wwlln.net) to provide groundtruth location/time of the lightning strokes. This poster will describe latest results. Jacobson, A. R., R. H. Holzworth, R. F. Pfaff, and M. P. McCarthy (2011), Study of oblique whistlers in the low-latitude ionosphere, jointly with the C/NOFS satellite and the World-Wide Lightning Location Network, Annales Geophysicae, 29, 851-863. Pfaff, R., D. Rowland, H. Freudenreich, K. Bromund, K. Le, M. Acuna, J. Klenzing, C. Liebrecht, S. Martin, W. J. Burke, N. C. Maynard, D. E. Hunton, P. A. Roddy, J. O. Ballenthin, and G. R. Wilson (2010), Observations of DC electric fields in the low-latitude ionosphere and their variations with
Mass Limit for the standard model Higgs boson with the full LEP I ALEPH data sample
Buskulic, Damir; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Nief, J Y; Odier, P; Pietrzyk, B; Casado, M P; Chmeissani, M; Crespo, J M; Delfino, M C; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Padilla, C; Park, I C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Lutters, G; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Pacheco, A; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schmitt, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wagner, A; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rosnet, P; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Rensch, B; Wäänänen, A; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Teixeira-Dias, P; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Abbaneo, D; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Moutoussi, A; Nash, J; Sedgbeer, J K; Stacey, A M; Williams, M D; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Williams, M I; Galla, A; Giehl, I; Greene, A M; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Ragusa, F; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Choi, Y; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Höcker, A; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Schune, M H; Simion, S; Veillet, J J; Videau, I; Zerwas, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Palla, Fabrizio; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Walsh, J; Blair, G A; Bryant, L M; Cerutti, F; Chambers, J T; Gao, Y; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Köksal, A; Lehto, M H; Newton, W M; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Büscher, V; Cowan, G D; Grupen, Claus; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Scott, I J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G
1996-01-01
background from the electroweak process e+e- --> l+ l- q qbar. This search results in a 95% C.L. lower limit on the Higgs boson mass of $63.9$~\\Gcs. The reaction e+e- --> HZ* is used to search for the standard model Higgs boson in the H nu nubar and the H l+ l- channels. The data sample corresponds to about 4.5 million hadronic Z decays collected by the ALEPH experiment at LEP from 1989 to 1995 at centre-of-mass energies at and around the Z peak. Three candidate events are found in the H mu+ mu- channel, in agreement with the expected
Institute of Scientific and Technical Information of China (English)
王伟明; 刘嘉; 苏建中; 殷树言; 马德
2004-01-01
This paper presents an integrated simulation model for full digital controlled PMIG/MAG welding system with Matlab/Simulink, and it consists of power inverter, digital control system and dynamic arc-load model. An integrated simulation study was done for full digital PMIG/MAG welding, and a method of connecting dynamic arc-load model to the system with controlled current source was presented, in addition, the simulation results were utilized to study the issues of digital control PMIG/MAG welding in this paper. The experimental results validated the developed simulation model, and this simulation study can be applied in implementation of the full digital PMIG/MAG welding and analysis of system dynamic process.
Directory of Open Access Journals (Sweden)
Pei-Rong Wang
2016-01-01
Full Text Available In previous reports, we and other groups have shown that proliferating hepatocytes are formed by the fusion of donor hematopoietic cells with host hepatocytes in the Fah−/− model. Thus, it would be interesting to determine whether cell fusion occurs during malignancy. However, it is difficult to demonstrate such processes using this model. Therefore, we established a new strain to study the processes of regenerating nodules and malignancy and their origins. The FAH−/− mouse model was crossed with the ROSAnZ strain and their offspring was genotyped for FAH−/− and ROSAnZ mutations to create a new strain (Fah−/−-ROSAnZ. Using this strain as recipients, we performed bone marrow transplantation experiments. As a result, we could not demonstrate the presence of any epithelial cells except hepatocytes that were of donor origin in regenerating tissue, and no evidence of cell fusion was found in tumors. The hepatic malignancy was of host origin in these mice. There was higher expression of extracellular matrix proteins and more inflammatory cells in liver tumor nodules than in regenerating normal liver nodules. Hepatocytes generated by fusion with bone marrow cells did not form malignant tumors. Extracellular matrix and inflammatory cells had significantly accumulated in liver tumors.
Global existence for a hydrogen storage model with full energy balance
Bonetti, Elena; Laurençot, Philippe
2011-01-01
A thermo-mechanical model describing hydrogen storage by use of metal hydrides has been recently proposed in a paper by Bonetti, Fr\\'emond and Lexcellent. It describes the formation of hydrides using the phase transition approach. By virtue of the laws of continuum thermo-mechanics, the model leads to a phase transition problem in terms of three state variables: the temperature, the phase parameter representing the fraction of one solid phase, and the pressure, and is derived within a generalization of the principle of virtual powers proposed by Fr\\'emond accounting for micro-forces, responsible for the phase transition, in the whole energy balance of the system. Three coupled nonlinear partial differential equations combined with initial and boundary conditions have to be solved. The main difficulty in investigating the resulting system of partial differential equations relies on the presence of the squared time derivative of the order parameter in the energy balance equation. Here, the global existence of a...
DEFF Research Database (Denmark)
Pors, Susanne E.; Chadfield, Mark S.; Sorensen, Dorte B.
2016-01-01
Host-pathogen interactions of Pasteurella multocida isolates of different origin were studied in a mouse model, focusing on pathology, bacterial load and expression of the metalloproteinase MMP9 and its inhibitor TIMP1. Intranasal inoculation with one of three doses (10(6), 10(4), 10(2) CFU...
Testing a Model of Resistance to Peer Pressure among Mexican-Origin Adolescents
Bamaca, Mayra Y.; Umana-Taylor, Adriana J.
2006-01-01
This study examined the factors associated with resistance to peer pressure toward antisocial behaviors among a sample of Mexican-origin adolescents (n=564) living in a large Southwestern city in the U.S. A model examining the influence of generational status, emotional autonomy from parents, and self-esteem on resistance to peer pressure was…
Testing a Model of Resistance to Peer Pressure among Mexican-Origin Adolescents
Bamaca, Mayra Y.; Umana-Taylor, Adriana J.
2006-01-01
This study examined the factors associated with resistance to peer pressure toward antisocial behaviors among a sample of Mexican-origin adolescents (n=564) living in a large Southwestern city in the U.S. A model examining the influence of generational status, emotional autonomy from parents, and self-esteem on resistance to peer pressure was…
Modeling Cellular Networks with Full Duplex D2D Communication: A Stochastic Geometry Approach
Ali, Konpal S.
2016-08-24
Full-duplex (FD) communication is optimistically promoted to double the spectral efficiency if sufficient self-interference cancellation (SIC) is achieved. However, this is not true when deploying FD-communication in a large-scale setup due to the induced mutual interference. Therefore, a large-scale study is necessary to draw legitimate conclusions about gains associated with FD-communication. This paper studies the FD operation for underlay device-to-device (D2D) communication sharing the uplink resources in cellular networks. We propose a disjoint fine-tuned selection criterion for the D2D and FD modes of operation. Then, we develop a tractable analytical paradigm, based on stochastic geometry, to calculate the outage probability and rate for cellular and D2D users. The results reveal that even in the case of perfect SIC, due to the increased interference injected to the network by FD-D2D communication, having all proximity UEs transmit in FD-D2D is not beneficial for the network. However, if the system parameters are carefully tuned, non-trivial network spectral-efficiency gains (64% shown) can be harvested. We also investigate the effects of imperfect SIC and D2D-link distance distribution on the harvested FD gains.
Full Wave Parallel Code for Modeling RF Fields in Hot Plasmas
Spencer, Joseph; Svidzinski, Vladimir; Evstatiev, Evstati; Galkin, Sergei; Kim, Jin-Soo
2015-11-01
FAR-TECH, Inc. is developing a suite of full wave RF codes in hot plasmas. It is based on a formulation in configuration space with grid adaptation capability. The conductivity kernel (which includes a nonlocal dielectric response) is calculated by integrating the linearized Vlasov equation along unperturbed test particle orbits. For Tokamak applications a 2-D version of the code is being developed. Progress of this work will be reported. This suite of codes has the following advantages over existing spectral codes: 1) It utilizes the localized nature of plasma dielectric response to the RF field and calculates this response numerically without approximations. 2) It uses an adaptive grid to better resolve resonances in plasma and antenna structures. 3) It uses an efficient sparse matrix solver to solve the formulated linear equations. The linear wave equation is formulated using two approaches: for cold plasmas the local cold plasma dielectric tensor is used (resolving resonances by particle collisions), while for hot plasmas the conductivity kernel is calculated. Work is supported by the U.S. DOE SBIR program.
Pulsating electromagnetic fields (PEMF) used to treat full thickness defects in the rabbit model
Energy Technology Data Exchange (ETDEWEB)
Andino, R.V.; Feldman, D. (Univ. of Alabama, Birmingham (United States))
1991-03-15
Skin ulcers have historically been treated by passive therapy. One active treatment, PEMF, has shown promise. The objective of this study was, therefore, to examine the effects of a current induced by a PEMF on full thickness defects in white New Zealand rabbits. It was hypothesized that the induced current would increase neutrophil, macrophage, and fibroblast proliferation during the wound healing process. This in turn, would lead to an increase in collagen deposition in the wound and thus increase the healing rate. A device which produces a 2.8 mTesla magnetic field at a frequency of 75 Hz was donated by the EBI Corp. and modified so that a rabbit could be fit between its two induction coils. Two rabbits with four 3 x 3 cm wounds each were stimulated for 3.5 hours/day for 1 week and two rabbits with identical wounds were stimulated for the same time period daily but for 2 weeks. These wounds were compared to unstimulated controls. Preliminary results indicate that the healing rate in the PEMF animals increased by about 25-30% and the number of neutrophils is greater in the one week stimulated group. In the two week stimulated group, the collagen deposition is greater, denser and in alignment.
Towards the full information chain theory: answer depth and source models
Perevalov, Eugene
2012-01-01
A problem of optimal information acquisition for its use in general decision making problems is considered. This motivates the need for developing quantitative measures of information sources' capabilities for supplying accurate information depending on the particular content of the latter. A companion article developed the notion of a question difficulty functional for questions concerning input data for a decision making problem. Here, answers which an information source may provide in response to such questions are considered. In particular, a real valued answer depth functional measuring the degree of accuracy of such answers is introduced and its overall form is derived under the assumption of isotropic knowledge structure of the information source. Additionally, information source models that relate answer depth to question difficulty are discussed. It turns out to be possible to introduce a notion of an information source capacity as the highest value of the answer depth the source is capable of provid...
Full-kinetic elve model simulations and their comparison with the ISUAL observed events
Kuo, C.; Huang, T.; Chang, S.; Chou, J.; Lee, L.; Chen, A. B.; Su, H.; Hsu, R.; Frey, H. U.; Mende, S. B.; Takahashi, Y.; Lee, L.
2011-12-01
The duration of the optical emissions from elves is relatively short (kinetic chemistry in elves [Sentman et al., 2008; Kuo et al., 2011]. The modeling results can provide the relatively intensity ratios of the major and the minor emissions in elves. The estimated relative intensities can be used to analyze for the involved radiative states and to infer their percentage that fall within the ISUAL Imager filter passing band. The simulation results could also be useful in designing the imager filters for the future TLE survey missions. [*Works were supported in part by the National Space Organization (NSPO) and the National Science Council (NSC) in Taiwan under grants NSC 99-2112-M-006-006-MY3, NSC 99-2111-M-006-001-MY3, NSC 100-2119-M-006-015
Full C P T -even photon sector of the standard model extension at finite temperature
Escobar, Carlos A.; Garcia, Marcos A. G.
2015-07-01
We study the finite temperature behavior of the C P T -even pure-photon sector of the standard model extension, which is defined by the standard Maxwell Lagrangian plus the term (kF)μν α βFμ νFα β. The Hamiltonian analysis is performed, from which the degrees of freedom and constraints of the theory are derived. We have explicitly calculated the partition function for an arbitrary configuration of the (kF)μν α β coefficients, to second order, and we have used it to obtain the thermodynamic properties of the modified photon sector. We find the correction to the frequency dependence in Planck's radiation law, and we identify that the total energy density is adjusted, relative to the standard scenario, by a global proportionality constant containing the Lorentz-violating contributions. Nevertheless, the equation of state is not affected by these modifications.
Towards Achieving the Full Clinical Potential of Proton Therapy by Inclusion of LET and RBE Models
Energy Technology Data Exchange (ETDEWEB)
Jones, Bleddyn [Gray Laboratory, CRUK/MRC Oxford Oncology Institute, The University of Oxford, ORCRB-Roosevelt Drive, Oxford OX3 7DQ (United Kingdom)
2015-03-17
Despite increasing use of proton therapy (PBT), several systematic literature reviews show limited gains in clinical outcomes, with publications mostly devoted to recent technical developments. The lack of randomised control studies has also hampered progress in the acceptance of PBT by many oncologists and policy makers. There remain two important uncertainties associated with PBT, namely: (1) accuracy and reproducibility of Bragg peak position (BPP); and (2) imprecise knowledge of the relative biological effect (RBE) for different tissues and tumours, and at different doses. Incorrect BPP will change dose, linear energy transfer (LET) and RBE, with risks of reduced tumour control and enhanced toxicity. These interrelationships are discussed qualitatively with respect to the ICRU target volume definitions. The internationally accepted proton RBE of 1.1 was based on assays and dose ranges unlikely to reveal the complete range of RBE in the human body. RBE values are not known for human (or animal) brain, spine, kidney, liver, intestine, etc. A simple efficiency model for estimating proton RBE values is described, based on data of Belli et al. and other authors, which allows linear increases in α and β with LET, with a gradient estimated using a saturation model from the low LET α and β radiosensitivity parameter input values, and decreasing RBE with increasing dose. To improve outcomes, 3-D dose-LET-RBE and bio-effectiveness maps are required. Validation experiments are indicated in relevant tissues. Randomised clinical studies that test the invariant 1.1 RBE allocation against higher values in late reacting tissues, and lower tumour RBE values in the case of radiosensitive tumours, are also indicated.
A modelling approach to determine the origin of urban ground water.
Trowsdale, Sam A; Lerner, David N
2007-04-01
A simple modelling approach was developed to link patterns of urban land-use with ground water flow and chemistry in three dimensions and was applied to characterize the origin of recharge in the aquifer beneath the old industrial city of Nottingham, UK. The approach involved dividing land uses into types, and times into periods, and assigning the recharge from each an individual tracer-solute with a unit concentration. The computer code MT3DMS was used to track the multiple tracer-solutes in transient, three-dimensional simulations of the important urban aquifer. A depth-specific hydrochemical dataset collected in parallel supported the model predictions. At depth under the industrial area studied, a large component of ground water originated of older agricultural origin, with relatively low nitrate concentrations. Shallower ground water originated mainly from residential and industrial areas, with higher nitrate concentrations probably arising from leaking sewers and contaminated land. The results highlighted the spectrum of ground water from different origins that amalgamate even at short well screens in a non-pumped borehole and remind us that the non-point-source pollution of ground water from anthropogenic activities will involve more years of slow degradation of quality.
An origin of the universe: a model alternative to Big Bang
Mercik, Andrzej; Mercik, Szymon
2006-01-01
We propose a new approach to the model of an origin of the universe built by Oscar Klein and Hannes Alfv\\'{e}n. Some modifications of assumptions underlying the model result in a possible scenario of the universe creation consistent with observations. We explain the large scale structre of the universe and we estimate the Hubble constant value as well as the number of galaxies in the universe. The model does not require many assumptions made in the model based on the Big Bang idea.
Wet oxidation of sewage sludge: full-scale experience and process modeling.
Bertanza, Giorgio; Galessi, Raniero; Menoni, Laura; Salvetti, Roberta; Slavik, Edoardo; Zanaboni, Sabrina
2015-05-01
Nowadays, sewage sludge management represents one of the most important issues in wastewater treatment. Within the European project "ROUTES," wet oxidation (WO) was proposed for sludge minimization. Four different types of sludge were treated in an industrial WO plant: (1) municipal primary sludge (chemical oxygen demand COD: 73.0 g/L; volatile suspended solid VSS: 44.1 g/L); (2) secondary sludge from an industrial wastewater treatment plant (WWTP) without primary sedimentation (COD: 71.8 g/L; VSS: 34.2 g/L); (3) secondary sludge from a mixed municipal and industrial WWTP without primary sedimentation (COD: 61.9 g/L; VSS: 38.7 g/L); and (4) mixed primary (70%) and secondary (30%) municipal sludge (COD: 81.2 g/L; VSS: 40.6 g/L). The effect of process parameters (temperature, reaction time, oxygen dosage) on WO performance was investigated. Depending on operating conditions, VSS and COD removal efficiency varied in the range 80-97% and 43-71%, respectively. A correlation between process efficiency and the initial VSS/TSS (total suspended solids) ratio was highlighted. Furthermore, a mathematical model of WO process for simulating VSS and COD profiles was developed.
Model-based control structure design of a full-scale WWTP under the retrofitting process.
Machado, V C; Lafuente, J; Baeza, J A
2015-01-01
The anoxic-oxic (A/O) municipal wastewater treatment plant (WWTP) of Manresa (Catalonia, Spain) was studied for a possible conversion to an anaerobic/anoxic/oxic (A2/O) configuration to promote enhanced biological phosphorus removal. The control structure had to be redesigned to satisfy the new necessity to control phosphorus concentration, besides ammonium and nitrate concentrations (main pollutant concentrations). Thereby, decentralized control structures with proportional-integral-derivative (PID) controllers and centralized control structures with model-predictive controllers (MPC) were designed and tested. All the designed control structures had their performance systematically tested regarding effluent quality and operating costs. The centralized control structure, A2/O-3-MPC, achieved the lowest operating costs with the best effluent quality using the A2/O plant configuration for the Manresa WWTP. The controlled variables used in this control structure were ammonium in the effluent, nitrate at the end of the anoxic zone and phosphate at the end of the anaerobic zone, while the manipulated variables were the internal and external recycle flow rates and the dissolved oxygen setpoint in the aerobic reactors.
Full SED fitting with the KOSMA-\\tau\\ PDR code - I. Dust modelling
Röllig, M; Ossenkopf, V; Glück, C
2012-01-01
We revised the treatment of interstellar dust in the KOSMA-\\tau\\ PDR model code to achieve a consistent description of the dust-related physics in the code. The detailed knowledge of the dust properties is then used to compute the dust continuum emission together with the line emission of chemical species. We coupled the KOSMA-\\tau\\ PDR code with the MCDRT (multi component dust radiative transfer) code to solve the frequency-dependent radiative transfer equations and the thermal balance equation in a dusty clump under the assumption of spherical symmetry, assuming thermal equilibrium in calculating the dust temperatures, neglecting non-equilibrium effects. We updated the calculation of the photoelectric heating and extended the parametrization range for the photoelectric heating toward high densities and UV fields. We revised the computation of the H2 formation on grain surfaces to include the Eley-Rideal effect, thus allowing for high-temperature H2 formation. We demonstrate how the different optical propert...
Is the full susceptibility of the square-lattice Ising model a differentially algebraic function?
Guttmann, A. J.; Jensen, I.; Maillard, J.-M.; Pantone, J.
2016-12-01
We study the class of non-holonomic power series with integer coefficients that reduce, modulo primes, or powers of primes, to algebraic functions. In particular we try to determine whether the susceptibility of the square-lattice Ising model belongs to this class, and more broadly whether the susceptibility is a solution of a differentially algebraic equation. Initial results on Tutte's nonlinear ordinary differential equation (ODE) and other simple quadratic nonlinear ODEs suggest that a large set of differentially algebraic power series solutions with integer coefficients might reduce to algebraic functions modulo primes, or powers of primes. Since diagonals of rational functions are well-known to reduce, modulo primes, or powers of primes, to algebraic functions, a large subset of differentially algebraic power series with integer coefficients may be viewed as a natural ‘nonlinear’ generalisation of diagonals of rational functions. Here we give several examples of series with integer coefficients and non-zero radius of convergence that reduce to algebraic functions modulo (almost) every prime (or power of a prime). These examples satisfy differentially algebraic equations with the encoding polynomial occasionally possessing quite high degree (and thus difficult to identify even with long series). These examples shed important light on the very nature of such differentially algebraic series. Additionally, we have extended both the high- and low-temperature Ising square-lattice susceptibility series to 5043 coefficients. We find that even this long series is insufficient to determine whether it reduces to algebraic functions modulo 3, 5, etc. This negative result is in contrast to the comparatively easy confirmation that the corresponding series reduce to algebraic functions modulo powers of 2. Finally we show that even with 5043 terms we are unable to identify an underlying differentially algebraic equation for the susceptibility, ruling out a number of
A full economic analysis of switchgrass under different scenarios in Italy estimated by BEE model
Energy Technology Data Exchange (ETDEWEB)
Monti, A.; Fazio, S.; Venturi, G. [Department of Agroenvironmental Science and Technologies, Bologna (Italy); Lychnaras, V.; Soldatos, P. [Agricultural University of Athens, Athens (Greece). Laboratory of Agribusiness Management
2007-04-15
Three different scenarios of switchgrass (Panicum virgatum L.) cultivation (high, mild and low) in two different environmental conditions (North and South Italy) were economically analysed by the computerized model BEE. The dataset was mostly generated from an 8.6 ha field of switchgrass planted in 2002 at the University of Bologna (North Italy). Annual equivalent costs (AEC) and break-even yield (BEY, i.e. the dry matter yield at which cost equals selling price) of each scenario were calculated to assess the feasibility of each scenario. AEC ranged from EUR511 to EUR1.257 ha{sup -1} being always higher in northern than southern regions. As expected, BEY varied to an extent depending on input levels. BEY was clearly higher under intensive cropping systems (H{sub S}) compared to mild-(M{sub S}) and low-input (L{sub S}) scenarios. However, even for M{sub S} or L{sub S}, BEY generally exceeded the harvested yield. Therefore, we can conclude that, at the market price of EUR55 Mg{sup -1} (dry basis), switchgrass can be hardly grown both in North and South Italy. However, the biomass market price appeared surprisingly underestimated if compared to the unit energy price of crude oil, therefore a desirable increase of biomass price could be expected in the next few years. Sensitivity analysis showed that biomass price strongly affects BEY, and this was especially found in H{sub S}. Furthermore, the differences in BEY between L{sub S} and H{sub S} clearly decreased with increasing market prices. Therefore, H{sub S} could be better indicated than L{sub S} at high market prices. Switchgrass was found to be more profitable than some conventional crops to an extent depending on the yield higher than BEY (Y{sub i}). At the current biomass price, Y{sub i} was from less than 1 Mg ha{sup -1} (maize and alfalfa) to more than 4 Mg ha{sup -1} (sugarbeet). (author)
Directory of Open Access Journals (Sweden)
Boulais-Sinou Romain
2016-01-01
Full Text Available A new full field numerical approach for the simulation of dynamic and post-dynamic recrystallization will be detailed. A level Set framework is employed to link a crystal plasticity finite element method with the modeling of recrystallization. Plasticity is calculated through the activation of slip systems and provides predictions for both SSDs and GNDs densities. These predictions control the activation and kinetics of recrystallization. All the developments are applied on 304L stainless steel.
Yu, Hongju; Rignot, Eric; Morlighem, Mathieu; Seroussi, Helene
2016-01-01
Thwaites Glacier (TG), West Antarctica, has been losing mass and retreating rapidly in the past three decades. Here we present a two-dimensional, Full-Stokes (FS) modeling study of the grounding line dynamics and iceberg calving of TG. First, we compare FS with two simplified models, the higher-order (HO) model and the shallow-shelf approximation (SSA) model, to determine the impact of changes in ice shelf basal melt rate on grounding line dynamics. Second, we combine FS with the Linear Elast...
Energy Technology Data Exchange (ETDEWEB)
Kramer, Sharlotte Lorraine Bolyard; Scherzinger, William M.
2014-09-01
The Virtual Fields Method (VFM) is an inverse method for constitutive model parameter identication that relies on full-eld experimental measurements of displacements. VFM is an alternative to standard approaches that require several experiments of simple geometries to calibrate a constitutive model. VFM is one of several techniques that use full-eld exper- imental data, including Finite Element Method Updating (FEMU) techniques, but VFM is computationally fast, not requiring iterative FEM analyses. This report describes the im- plementation and evaluation of VFM primarily for nite-deformation plasticity constitutive models. VFM was successfully implemented in MATLAB and evaluated using simulated FEM data that included representative experimental noise found in the Digital Image Cor- relation (DIC) optical technique that provides full-eld displacement measurements. VFM was able to identify constitutive model parameters for the BCJ plasticity model even in the presence of simulated DIC noise, demonstrating VFM as a viable alternative inverse method. Further research is required before VFM can be adopted as a standard method for constitu- tive model parameter identication, but this study is a foundation for ongoing research at Sandia for improving constitutive model calibration.
Electron spin and the origin of Bio-homochirality II. Prebiotic inorganic-organic reaction model
Wang, Wei
2014-01-01
The emergence of biomolecular homochirality is a critically important question about life phenomenon and the origins of life. In a previous paper (arXiv:1309.1229), I tentatively put forward a new hypothesis that the emergence of a single chiral form of biomolecules in living organisms is specifically determined by the electron spin state during their enzyme-catalyzed synthesis processes. However, how a homochirality world of biomolecules could have formed in the absence of enzymatic networks before the origins of life remains unanswered. Here I discussed the electron spin properties in Fe3S4, ZnS, and transition metal doped dilute magnetic ZnS, and their possible roles in the prebiotic synthesis of chiral molecules. Since the existence of these minerals in hydrothermal vent systems is matter of fact, the suggested prebiotic inorganic-organic reaction model, if can be experimentally demonstrated, may help explain where and how life originated on early Earth.
Directory of Open Access Journals (Sweden)
Jean-Philippe Auger
2016-07-01
Full Text Available Multilocus sequence typing previously identified three predominant sequence types (STs of Streptococcus suis serotype 2: ST1 strains predominate in Eurasia while North American (NA strains are generally ST25 and ST28. However, ST25/ST28 and ST1 strains have also been isolated in Asia and NA, respectively. Using a well-standardized mouse model of infection, the virulence of strains belonging to different STs and different geographical origins was evaluated. Results demonstrated that although a certain tendency may be observed, S. suis serotype 2 virulence is difficult to predict based on ST and geographical origin alone; strains belonging to the same ST presented important differences of virulence and did not always correlate with origin. The only exception appears to be NA ST28 strains, which were generally less virulent in both systemic and central nervous system (CNS infection models. Persistent and high levels of bacteremia accompanied by elevated CNS inflammation are required to cause meningitis. Although widely used, in vitro tests such as phagocytosis and killing assays require further standardization in order to be used as predictive tests for evaluating virulence of strains. The use of strains other than archetypal strains has increased our knowledge and understanding of the S. suis serotype 2 population dynamics.
Determination of Original Infection Source of H7N9 Avian Influenza by Dynamical Model
Zhang, Juan; Jin, Zhen; Sun, Gui-Quan; Sun, Xiang-Dong; Wang, You-Ming; Huang, Baoxu
2014-05-01
H7N9, a newly emerging virus in China, travels among poultry and human. Although H7N9 has not aroused massive outbreaks, recurrence in the second half of 2013 makes it essential to control the spread. It is believed that the most effective control measure is to locate the original infection source and cut off the source of infection from human. However, the original infection source and the internal transmission mechanism of the new virus are not totally clear. In order to determine the original infection source of H7N9, we establish a dynamical model with migratory bird, resident bird, domestic poultry and human population, and view migratory bird, resident bird, domestic poultry as original infection source respectively to fit the true dynamics during the 2013 pandemic. By comparing the date fitting results and corresponding Akaike Information Criterion (AIC) values, we conclude that migrant birds are most likely the original infection source. In addition, we obtain the basic reproduction number in poultry and carry out sensitivity analysis of some parameters.
Chaos in a dynamic model of traffic flows in an origin-destination network
Zhang, Xiaoyan; Jarrett, David F.
1998-06-01
In this paper we investigate the dynamic behavior of road traffic flows in an area represented by an origin-destination (O-D) network. Probably the most widely used model for estimating the distribution of O-D flows is the gravity model, [J. de D. Ortuzar and L. G. Willumsen, Modelling Transport (Wiley, New York, 1990)] which originated from an analogy with Newton's gravitational law. The conventional gravity model, however, is static. The investigation in this paper is based on a dynamic version of the gravity model proposed by Dendrinos and Sonis by modifying the conventional gravity model [D. S. Dendrinos and M. Sonis, Chaos and Social-Spatial Dynamics (Springer-Verlag, Berlin, 1990)]. The dynamic model describes the variations of O-D flows over discrete-time periods, such as each day, each week, and so on. It is shown that when the dimension of the system is one or two, the O-D flow pattern either approaches an equilibrium or oscillates. When the dimension is higher, the behavior found in the model includes equilibria, oscillations, periodic doubling, and chaos. Chaotic attractors are characterized by (positive) Liapunov exponents and fractal dimensions.
Original analytic solution of a half-bridge modelled as a statically indeterminate system
Oanta, Emil M.; Panait, Cornel; Raicu, Alexandra; Barhalescu, Mihaela
2016-12-01
The paper presents an original computer based analytical model of a half-bridge belonging to a circular settling tank. The primary unknown is computed using the force method, the coefficients of the canonical equation being calculated using either the discretization of the bending moment diagram in trapezoids, or using the relations specific to the polygons. A second algorithm based on the method of initial parameters is also presented. Analyzing the new solution we came to the conclusion that most of the computer code developed for other model may be reused. The results are useful to evaluate the behavior of the structure and to compare with the results of the finite element models.
Energy Technology Data Exchange (ETDEWEB)
Uesaka, S. [Kyoto University, Kyoto (Japan). Faculty of Engineering; Watanabe, T.; Sassa, K. [Kyoto University, Kyoto (Japan)
1997-05-27
Algorithm is constructed and a program developed for a full-wave inversion (FWI) method utilizing the elastic wave equation in seismic exploration. The FWI method is a method for obtaining a physical property distribution using the whole observed waveforms as the data. It is capable of high resolution which is several times smaller than the wavelength since it can handle such phenomena as wave reflection and dispersion. The method for determining the P-wave velocity structure by use of the acoustic wave equation does not provide information about the S-wave velocity since it does not consider S-waves or converted waves. In an analysis using the elastic wave equation, on the other hand, not only P-wave data but also S-wave data can be utilized. In this report, under such circumstances, an inverse analysis algorithm is constructed on the basis of the elastic wave equation, and a basic program is developed. On the basis of the methods of Mora and of Luo and Schuster, the correction factors for P-wave and S-wave velocities are formulated directly from the elastic wave equation. Computations are performed and the effects of the hypocenter frequency and vibration transmission direction are examined. 6 refs., 8 figs.
This paper describes the measurement and model evaluation of formaldehyde source emissions from composite and solid wood furniture in a full-scale chamber under dynamic conditions using ASTM D 6670-01 (2007). Four brands of the same type furniture product were tested. The data we...
Directory of Open Access Journals (Sweden)
Polychronopoulou D.
2016-01-01
Full Text Available Fragmentation of α lamellae and subsequent spheroidization of α laths in α/β titanium alloys occurring during and after deformation are well known phenomena. We will illustrate the development of a new finite element methodology to model them. This new methodology is based on a level set framework to model the deformation and the ad hoc simultaneous and/or subsequent interfaces kinetics. We will focus, at yet, on the modeling of the surface diffusion at the α/β phase interfaces and the motion by mean curvature at the α/α grain interfaces.
TWEETS AND FACEBOOK POSTS, THE NOVELTY TECHNIQUES IN THE CREATION OF ORIGIN-DESTINATION MODELS
Directory of Open Access Journals (Sweden)
H. K. Malema
2016-06-01
Full Text Available Social media and big data have emerged to be a useful source of information that can be used for planning purposes, particularly transportation planning and trip-distribution studies. Cities in developing countries such as South Africa often struggle with out-dated, unreliable and cumbersome techniques such as traffic counts and household surveys to conduct origin and destination studies. The emergence of ubiquitous crowd sourced data, big data, social media and geolocation based services has shown huge potential in providing useful information for origin and destination studies. Perhaps such information can be utilised to determine the origin and destination of commuters using the Gautrain, a high-speed railway in Gauteng province South Africa. To date little is known about the origins and destinations of Gautrain commuters. Accordingly, this study assesses the viability of using geolocation-based services namely Facebook and Twitter in mapping out the network movements of Gautrain commuters. Explorative Spatial Data Analysis (ESDA, Echo-social and ArcGis software were used to extract social media data, i.e. tweets and Facebook posts as well as to visualize the concentration of Gautrain commuters. The results demonstrate that big data and geolocation based services have the significant potential to predict movement network patterns of commuters and this information can thus, be used to inform and improve transportation planning. Nevertheless use of crowd sourced data and big data has privacy concerns that still need to be addressed.
Directory of Open Access Journals (Sweden)
Heverton A. Pereira
2014-11-01
Full Text Available Wind power has achieved technological evolution, and Grid Code (GC requirements forced wind industry consolidation in the last three decades. However, more studies are necessary to understand how the dynamics inherent in this energy source interact with the power system. Traditional energy production usually contains few high power unit generators; however, Wind Power Plants (WPPs consist of dozens or hundreds of low-power units. Time domain simulations of WPPs may take too much time if detailed models are considered in such studies. This work discusses reduced order models used in interconnection studies of synchronous machines with full converter technology. The performance of all models is evaluated based on time domain simulations in the Simulink/MATLAB environment. A detailed model is described, and four reduced order models are compared using the performance index, Normalized Integral of Absolute Error (NIAE. Models are analyzed during wind speed variations and balanced voltage dip. During faults, WPPs must be able to supply reactive power to the grid, and this characteristic is analyzed. Using the proposed performance index, it is possible to conclude if a reduced order model is suitable to represent the WPPs dynamics on grid studies.
Ou, Hua-Se; Wei, Chao-Hai; Wu, Hai-Zhen; Mo, Ce-Hui; He, Bao-Yan
2015-10-01
This study proposed a sequential modeling approach using an artificial neural network (ANN) to develop four independent models which were able to predict biotreatment effluent variables of a full-scale coking wastewater treatment plant (CWWTP). Suitable structure and transfer function of ANN were optimized by genetic algorithm. The sequential approach, which included two parts, an influent estimator and an effluent predictor, was used to develop dynamic models. The former parts of models estimated the variations of influent COD, volatile phenol, cyanide, and NH4 (+)-N. The later parts of models predicted effluent COD, volatile phenol, cyanide, and NH4 (+)-N using the estimated values and other parameters. The performance of these models was evaluated by statistical parameters (such as coefficient of determination (R (2) ), etc.). Obtained results indicated that the estimator developed dynamic models for influent COD (R (2) = 0.871), volatile phenol (R (2) = 0.904), cyanide (R (2) = 0.846), and NH4 (+)-N (R (2) = 0.777), while the predictor developed feasible models for effluent COD (R (2) = 0.852) and cyanide (R (2) = 0.844), with slightly worse models for effluent volatile phenol (R (2) = 0.752) and NH4 (+)-N (R (2) = 0.764). Thus, the proposed modeling processes can be used as a tool for the prediction of CWWTP performance.
Bernacki, Marc; Scholtes, Benjamin; Settefrati, Amico; Bozzolo, Nathalie; Moussa, Charbel; Pino Muñoz, Daniel; Zhan, Yang; Rigal, Emmanuel; Dumont, Christian; Besnard, Remy; Besnard, Rémy; Poitrault, Isabelle; Demurger, Joëlle; Montouchet, Aurore; Bobin, Isabelle
2016-01-01
International audience; Metal forming modeling can be predictive only if the strain rate, strain and temperature dependency of the flow behaviour are correctly described. The mechanical properties and behaviour of metallic materials mainly depends on the content and structure of dislocation network, this points out the need to incorporate microstructure concepts into the numerical models. The goal is to correctly describe the main physical mechanisms occurring in metals during thermomechanica...
Arita, Ken-ichiro
2014-01-01
Shell structures in single-particle energy spectra are investigated against regular tetrahedral type deformation using radial power-law potential model. Employing a natural way of shape parametrization which interpolate sphere and regular tetrahedron, we find prominent shell effects at rather large tetrahedral deformations, which bring about shell energies much larger than the cases of spherical and quadrupole type shapes. We discuss the semiclassical origin of these anomalous shell structures using periodic orbit theory.
DEFF Research Database (Denmark)
Ekholm, Simon
1996-01-01
In this paper, a new high-resolution elevation model of Greenland, including the ice sheet as well as the ice free regions, is presented. It is the first published full coverage model, computed with an average resolution of 2 km and providing an unprecedented degree of detail. The topography...... airborne laser data from the analysis and treating them as ground truth observations. The mean accuracy of the ice sheet elevations is estimated to be 12-13 m, and it is found that on surfaces of a slope between 0.2 degrees and 0.8 degrees, corresponding to approximately 50% of the ice sheet, the model...... is modeled from a wide selection of data sources, including satellite radar altimetry from Geosat and ERS 1, airborne radar altimetry and airborne laser altimetry over the ice sheet, and photogrammetric and manual map scannings in the ice free region. The ice sheet model accuracy is evaluated by omitting...
DEFF Research Database (Denmark)
Pereira, Heverton A.; F. Cupertino, Allan; Teodorescu, Remus
2014-01-01
Wind power has achieved technological evolution, and Grid Code (GC) requirements forced wind industry consolidation in the last three decades. However, more studies are necessary to understand how the dynamics inherent in this energy source interact with the power system. Traditional energy...... in interconnection studies of synchronous machines with full converter technology. The performance of all models is evaluated based on time domain simulations in the Simulink/MATLAB environment. A detailed model is described, and four reduced order models are compared using the performance index, Normalized Integral...... of Absolute Error (NIAE). Models are analyzed during wind speed variations and balanced voltage dip. During faults, WPPs must be able to supply reactive power to the grid, and this characteristic is analyzed. Using the proposed performance index, it is possible to conclude if a reduced order model is suitable...
Kazadi Mbamba, Christian; Flores-Alsina, Xavier; John Batstone, Damien; Tait, Stephan
2016-09-01
The focus of modelling in wastewater treatment is shifting from single unit to plant-wide scale. Plant-wide modelling approaches provide opportunities to study the dynamics and interactions of different transformations in water and sludge streams. Towards developing more general and robust simulation tools applicable to a broad range of wastewater engineering problems, this paper evaluates a plant-wide model built with sub-models from the Benchmark Simulation Model No. 2-P (BSM2-P) with an improved/expanded physico-chemical framework (PCF). The PCF includes a simple and validated equilibrium approach describing ion speciation and ion pairing with kinetic multiple minerals precipitation. Model performance is evaluated against data sets from a full-scale wastewater treatment plant, assessing capability to describe water and sludge lines across the treatment process under steady-state operation. With default rate kinetic and stoichiometric parameters, a good general agreement is observed between the full-scale datasets and the simulated results under steady-state conditions. Simulation results show differences between measured and modelled phosphorus as little as 4-15% (relative) throughout the entire plant. Dynamic influent profiles were generated using a calibrated influent generator and were used to study the effect of long-term influent dynamics on plant performance. Model-based analysis shows that minerals precipitation strongly influences composition in the anaerobic digesters, but also impacts on nutrient loading across the entire plant. A forecasted implementation of nutrient recovery by struvite crystallization (model scenario only), reduced the phosphorus content in the treatment plant influent (via centrate recycling) considerably and thus decreased phosphorus in the treated outflow by up to 43%. Overall, the evaluated plant-wide model is able to jointly describe the physico-chemical and biological processes, and is advocated for future use as a tool for
Darwin's diagram of divergence of taxa as a causal model for the origin of species.
Bouzat, Juan L
2014-03-01
On the basis that Darwin's theory of evolution encompasses two logically independent processes (common descent and natural selection), the only figure in On the Origin of Species (the Diagram of Divergence of Taxa) is often interpreted as illustrative of only one of these processes: the branching patterns representing common ancestry. Here, I argue that Darwin's Diagram of Divergence of Taxa represents a broad conceptual model of Darwin's theory, illustrating the causal efficacy of natural selection in producing well-defined varieties and ultimately species. The Tree Diagram encompasses the idea that natural selection explains common descent and the origin of organic diversity, thus representing a comprehensive model of Darwin's theory on the origin of species. I describe Darwin's Tree Diagram in relation to his argumentative strategy under the vera causa principle, and suggest that the testing of his theory based on the evidence from the geological record, the geographical distribution of organisms, and the mutual affinities of organic beings can be framed under the hypothetico-deductive method. Darwin's Diagram of Divergence of Taxa therefore represents a broad conceptual model that helps understanding the causal construction of Darwin's theory of evolution, the structure of his argumentative strategy, and the nature of his scientific methodology.
Neuscamman, Stephanie; Yu, Kristen
2016-05-01
The results of the National Atmospheric Release Advisory Center (NARAC) model simulations are compared to measured data from the Full-Scale Radiological Dispersal Device (FSRDD) field trials. The series of explosive radiological dispersal device (RDD) experiments was conducted in 2012 by Defence Research and Development Canada (DRDC) and collaborating organizations. During the trials, a wealth of data was collected, including a variety of deposition and air concentration measurements. The experiments were conducted with one of the stated goals being to provide measurements to atmospheric dispersion modelers. These measurements can be used to facilitate important model validation studies. For this study, meteorological observations recorded during the tests are input to the diagnostic meteorological model, ADAPT, which provides 3-D, time-varying mean wind and turbulence fields to the LODI dispersion model. LODI concentration and deposition results are compared to the measured data, and the sensitivity of the model results to changes in input conditions (such as the particle activity size distribution of the source) and model physics (such as the rise of the buoyant cloud of explosive products) is explored. The NARAC simulations predicted the experimentally measured deposition results reasonably well considering the complexity of the release. Changes to the activity size distribution of the modeled particles can improve the agreement of the model results to measurement.
Ko, P; Park, Myeonghun; Yokoya, Hiroshi
2016-01-01
The general strategy for dark matter (DM) searches at colliders currently relies on simplified models. In this paper, we propose a new $t$-channel UV-complete simplified model that improves the existing simplified DM models in two important respects: (i) we impose the full SM gauge symmetry including the fact that the left-handed and the right-handed fermions have two independent mediators with two independent couplings, and (ii) we include the renormalization group evolution when we derive the effective Lagrangian for DM-nucleon scattering from the underlying UV complete models by integrating out the $t$-channel mediators. The first improvement will introduce a few more new parameters compared with the existing simplified DM models. In this study we look at the effect this broader set of free parameters has on direct detection and the mono-$X$ + MET ($X$=jet,$W,Z$) signatures at 13 TeV LHC while maintaining gauge invariance of the simplified model under the full SM gauge group. We find that the direct detect...
Liu, Fei; Sun, Guang-ming; He, Yong
2010-01-01
Near infrared (NIR) spectroscopy combined with variable selection method of modeling power was investigated for the fast and accurate geographical origin discrimination of auricularia auricula. A total of 240 samples of auriculari auricula were collected in the market, and the spectra of all samples were scanned within the spectral region of 1100-2500 nm. The calibration set was composed of 180 (45 samples for each origin) samples, and the remaining 60 samples were employed as the validation set. The optimal partial least squares (PLS) discriminant model was achieved after performance comparison of different preprocessing (Savitzky-Golay smoothing, standard normal variate, 1-derivative, and 2-derivative). The effective wavelengths, which were selected by modeling power (MP) and used as input data matrix of least squares-support vector machine (LS-SVM), were employed for the development of modeling power-least squares-support vector machine (MP-LS-SVM) model. Radial basis function (RBF) kernel was applied as kernel function. Three threshold methods for variable selection by modeling power were applied in MP-LSSVM models, and there were the values of modeling power higher than 0.95, higher than 0.90, and higher than 0.90 combined with peak location (0.90+Peak). The correct recognition ratio in the validation set was used as evaluation standards. The absolute error of prediction was set as 0.1, 0.2 and 0.5, which showed the wrong recognition threshold value. The results indicated that the MP-LS-SVM (0.90+Peak) model could achieve the optimal performance in all three absolute error standards (0.1, 0.2 and 0.5), and the correct recognition ratio was 98.3%, 100% and 100%, respectively. The variable selection threshold (0.90+Peak) was the most suitable one in the application of modeling power. It was concluded that modeling power was an effective variable selection method, and near infrared spectroscopy combined with MP-LS-SVM model was successfully applied for the origin
Skinner, Brian
2016-09-01
Same-sex sexual behaviour is ubiquitous in the animal kingdom, but its adaptive origins remain a prominent puzzle. Here, I suggest the possibility that same-sex sexual behaviour arises as a consequence of the competition between an evolutionary drive for a wide diversity in traits, which improves the adaptability of a population, and a drive for sexual dichotomization of traits, which promotes opposite-sex attraction and increases the rate of reproduction. This trade-off is explored via a simple mathematical `toy model'. The model exhibits a number of interesting features and suggests a simple mathematical form for describing the sexual orientation continuum.
Energy Technology Data Exchange (ETDEWEB)
Achim, Daniela [Monash University, Department of Chemical Engineering, Clayton, VIC (Australia); Naser, J.; Morsi, Y.S. [Swinburne University of Technology, Faculty of Engineering and Industrial Sciences, Hawthorn, VIC (Australia); Pascoe, S. [Yallourn Energy, Moe, VIC (Australia)
2009-11-15
In this paper a full scale combustion model incorporating upstream mill ducting of a large tangentially fired boiler with flue gas recirculation was examined numerically. Lagrangian particle tracking was used to determine the coal particle paths and the Eddy Dissipation Model for the analysis of the gas phase combustion. Moreover volatiles and gaseous char products, given off by the coal particles were modelled by Arrhenius single phase reactions and a transport equation was solved for each material given off by the particles. Thermal, prompt, fuel and reburn NO{sub x} models with presumed probability density functions were used to model NO{sub x} production and the discrete transfer radiation model was used to model radiation heat transfer. Generally, the findings indicated reasonable agreement with observed qualitative and quantitative data of incident heat flux on the walls. The model developed here could be used for a range of applications in furnace design and optimisation of gas emissions of coal fired boiler plants. (orig.)
García-Díez, Markel; Ballester, Joan; De Ridder, Koen; Hooyberghs, Hans; Lauwaet, Dirk; Rodó, Xavier
2016-04-01
As most of the population lives in urban environments, the simulation of the urban climate has become an important part of the global climate change impact assessment. However, due to the high resolution required, these simulations demand a large amount of computational resources. Here we present a comparison between a simplified fast urban climate model (UrbClim) and a widely used full mesoscale model, the Weather Research and Forecasting (WRF) model, over the city of Barcelona. In order to check the advantages and disadvantages of each approach, both simulations were compared with station data and with land surface temperature observations retrieved by satellites, focusing on the urban heat island. The effect of changing the UrbClim boundary conditions was studied too, by using low resolution global reanalysis data (70 km) and a higher resolution forecast model (15 km). Finally, a strict comparison of the computational resources consumed by both models was carried out. Results show that, generally, the performance of the simple model is comparable to or better than the mesoscale model. The exception are the winds and the day-to-day correlation in the reanalysis driven run, but these problems disappear when taking the boundary conditions from a higher resolution global model. UrbClim was found to run 133 times faster than WRF, using 4x times higher resolution and, thus, it is an efficient solution for running long climate change simulations over large city ensembles.
Calibrating OPC model with full CD profile data for 2D and 3D patterns using scatterometry
Dave, Aasutosh D.; Kritsun, Oleg; Deng, Yunfei; Yoshimoto, Kenji; Li, Jie; Hu, Jiangtao
2009-03-01
The ability to manage critical dimensions (CDs) of structures on IC devices is vital to improving product yield and performance. It is challenging to achieve accurate metrology data as the geometries shrink beyond 40 nm features. At this technology node CDSEM noise and resist LER are of significant concerns1. This paper examines the extendibility of scatterometry techniques to characterize structures that are close to limits of lithographic printing and to extract full profile information for 2D and 3D features for OPC model calibration2. The resist LER concerns are diminished because of the automatic averaging that scatterometry provides over the measurement pad; this represents a significant added value for proper OPC model calibration and verification. This work develops a comparison matrix to determine the impact of scatterometry data on OPC model calibration with conventional CDSEM measurements. The paper will report test results for the OPC model through process data for accuracy and predictability.
African Journals Online (AJOL)
IndexCopernicus Portal System
Regenerative Modeling, McGowan Institute for Regenerative Medicine, ... MODS: Multiple Organ Dysfunction Syndrome; NO: Nitric Oxide; PAMP: ... motor, behavioural or speech-language ..... The model that best reflects the clinical setting ... allows for assessment of compensatory ..... The epidemiology and modern.
Directory of Open Access Journals (Sweden)
Zahra Izadi
2014-12-01
Full Text Available More than half of all hydrocarbon reservoirs are Naturally Fractured Reservoirs (NFRs, in which production forecasting is a complicated function of fluid flow in a fracture-matrix system. Modelling of fluid flow in NFRs is challenging due to formation heterogeneity and anisotropy. Stress sensitivity and depletion effect on already-complex reservoir permeability add to the sophistication. Horizontal permeability anisotropy and stress sensitivity are often ignored or inaccurately taken into account when simulating fluid flow in NFRs. The aim of this paper is to present an integrated approach for evaluating the dynamic and true anisotropic nature of permeability in naturally fractured reservoirs. Among other features, this approach considers the effect of reservoir depletion on reservoir permeability tensor, allowing more realistic production forecasts. In this approach the NFR is discretized into grids for which an analytical model yields full permeability tensors. Then, fluid flow is modelled using the finite-element method to obtain pore-pressure distribution within the reservoir. Next, another analytical model evaluates the change in the aperture of individual fractures as a function of effective stress and rock mechanical properties. The permeability tensor of each grid is then updated based on the apertures obtained for the current time step. The integrated model proceeds according to the next prescribed time increments.
Tchamna, Rodrigue; Youn, Edward; Youn, Iljoong
2014-05-01
This paper focuses on the active safety of a full-vehicle nonlinear model during cornering. At first, a previously developed electronic stability controller (ESC) based on vehicle simplified model is applied to the full-car nonlinear model in order to control the vehicle yaw rate and side-slip angle. The ESC system was shown beneficial not only in tracking the vehicle path as close as possible, but it also helped in reducing the vehicle roll angle and influences ride comfort and road-holding capability; to tackle that issue and also to have better attitude motion, making use of optimal control theory the active suspension control gain is developed from a vehicle linear model and used to compute the active suspension control force of the vehicle nonlinear model. The active suspension control algorithm used in this paper includes the integral action of the suspension deflection in order to make zero the suspension deflection steady state and keep the vehicle chassis flat. Keeping the chassis flat reduces the vehicle load transfer and that is helpful for road holding and yaw rate tracking. The effects of the two controllers when they work together are analysed using various computer simulations with different steering wheel manoeuvres.
Shen, Weisen
2016-11-24
Using receiver functions, Rayleigh wave phase velocity dispersion determined from ambient noise and teleseismic earthquakes, and Rayleigh wave horizontal to vertical ground motion amplitude ratios from earthquakes observed across the PLUTONS seismic array, we construct a one-dimensional (1-D) S-wave velocity (Vs) seismic model with uncertainties for Uturuncu volcano, Bolivia, located in the central Andes and overlying the eastward-subducting Nazca plate. We find a fast upper crustal lid placed upon a low-velocity zone (LVZ) in the mid-crust. By incorporating all three types of measurements with complimentary sensitivity, we also explore the average density and Vp/Vs (ratio of P-wave to S-wave velocity) structures beneath the young silicic volcanic field. We observe slightly higher Vp/Vs and a decrease in density near the LVZ, which implies a dacitic source of the partially molten magma body. We exploit the impact of the 1-D model on full moment tensor inversion for the two largest local earthquakes recorded (both magnitude ∼3), demonstrating that the 1-D model influences the waveform fits and the estimated source type for the full moment tensor. Our 1-D model can serve as a robust starting point for future efforts to determine a three-dimensional velocity model for Uturuncu volcano.
Energy Technology Data Exchange (ETDEWEB)
Koning, J; Rieben, R; Rodrigue, G
2004-12-09
We measure the loss of power incurred by the bending of a single mode step-indexed optical fiber using vector finite element modeling of the full-wave Maxwell equations in the optical regime. We demonstrate fewer grid elements can be used to model light transmission in longer fiber lengths by using high-order basis functions in conjunction with a high order energy conserving time integration method. The power in the core is measured at several points to determine the percentage loss. We also demonstrate the effect of bending on the light polarization.
2017-03-27
USAARL Report No. 2017-10 Modeling of a Monocular, Full-Color, Laser- Scanning, Helmet-Mounted Display for Aviator Situational Awareness By Thomas...Mounted Display for Aviator Situational Awareness N/A N/A N/A N/A N/A N/A Harding, Thomas H. Raatz, Maria E. Martin, John S. Rash, Clarence E. U.S...Huntsville, AL 35806-3302 PM Air Warrior, PEO Soldier Approved for public release; distribution unlimited. The modeling data and analysis presented in
An original traffic additional emission model and numerical simulation on a signalized road
Zhu, Wen-Xing; Zhang, Jing-Yu
2017-02-01
Based on VSP (Vehicle Specific Power) model traffic real emissions were theoretically classified into two parts: basic emission and additional emission. An original additional emission model was presented to calculate the vehicle's emission due to the signal control effects. Car-following model was developed and used to describe the traffic behavior including cruising, accelerating, decelerating and idling at a signalized intersection. Simulations were conducted under two situations: single intersection and two adjacent intersections with their respective control policy. Results are in good agreement with the theoretical analysis. It is also proved that additional emission model may be used to design the signal control policy in our modern traffic system to solve the serious environmental problems.
Directory of Open Access Journals (Sweden)
Peng Sun
2017-02-01
Full Text Available Free-piston linear generators (FPLGs have attractive application prospects for hybrid electric vehicles (HEVs owing to their high-efficiency, low-emissions and multi-fuel flexibility. In order to achieve long-term stable operation, the hybrid system design and full-cycle operation strategy are essential factors that should be considered. A 25 kW FPLG consisting of an internal combustion engine (ICE, a linear electric machine (LEM and a gas spring (GS is designed. To improve the power density and generating efficiency, the LEM is assembled with two modular flat-type double-sided PM LEM units, which sandwich a common moving-magnet plate supported by a middle keel beam and bilateral slide guide rails to enhance the stiffness of the moving plate. For the convenience of operation processes analysis, the coupling hybrid system is modeled mathematically and a full cycle simulation model is established. Top-level systemic control strategies including the starting, stable operating, fault recovering and stopping strategies are analyzed and discussed. The analysis results validate that the system can run stably and robustly with the proposed full cycle operation strategy. The effective electric output power can reach 26.36 kW with an overall system efficiency of 36.32%.
Directory of Open Access Journals (Sweden)
Alba Sandyra Bezerra Lopes
2012-01-01
Full Text Available The motion estimation is the most complex module in a video encoder requiring a high processing throughput and high memory bandwidth, mainly when the focus is high-definition videos. The throughput problem can be solved increasing the parallelism in the internal operations. The external memory bandwidth may be reduced using a memory hierarchy. This work presents a memory hierarchy model for a full-search motion estimation core. The proposed memory hierarchy model is based on a data reuse scheme considering the full search algorithm features. The proposed memory hierarchy expressively reduces the external memory bandwidth required for the motion estimation process, and it provides a very high data throughput for the ME core. This throughput is necessary to achieve real time when processing high-definition videos. When considering the worst bandwidth scenario, this memory hierarchy is able to reduce the external memory bandwidth in 578 times. A case study for the proposed hierarchy, using 32×32 search window and 8×8 block size, was implemented and prototyped on a Virtex 4 FPGA. The results show that it is possible to reach 38 frames per second when processing full HD frames (1920×1080 pixels using nearly 299 Mbytes per second of external memory bandwidth.
Park, Shin Ae; Teixeira, Leandro B C; Raghunathan, Vijay Krishna; Covert, Jill; Dubielzig, Richard R; Isseroff, Roslyn Rivkah; Schurr, Michael; Abbott, Nicholas L; McAnulty, Jonathan; Murphy, Christopher J
2014-01-01
The excisional dorsal full-thickness skin wound model with or without splinting is widely utilized in wound healing studies using diabetic or normal mice. However, the effects of splinting on dermal wound healing have not been fully characterized, and there are limited data on the direct comparison of wound parameters in the splinted model between diabetic and normal mice. We compared full-thickness excisional dermal wound healing in db/db and heterozygous mice by investigating the effects of splinting, semi-occlusive dressing, and poly(ethylene glycol) treatment. Two 8-mm full-thickness wounds were made with or without splinting in db/db and heterozygous mice. Body weights, splint maintenance, wound contraction, wound closure, and histopathological parameters including reepithelialization, wound bed collagen deposition, and inflammation were compared between groups. Our results show that silicone splint application effectively reduced wound contraction in heterozygous and db/db mice. Splinted wounds, as opposed to nonsplinted wounds, exhibited no significant differences in wound closure between heterozygous and db/db mice. Finally, polyethylene glycol and the noncontact dressing had no significant effect on wound healing in heterozygous or db/db mice. We believe these findings will help investigators in selection of the appropriate wound model and data interpretation with fully defined parameters.
The role of regulation in the origin and synthetic modelling of minimal cognition.
Bich, Leonardo; Moreno, Alvaro
2016-10-01
In this paper we address the question of minimal cognition by investigating the origin of some crucial cognitive properties from the very basic organisation of biological systems. More specifically, we propose a theoretical model of how a system can distinguish between specific features of its interaction with the environment, which is a fundamental requirement for the emergence of minimal forms of cognition. We argue that the appearance of this capacity is grounded in the molecular domain, and originates from basic mechanisms of biological regulation. In doing so, our aim is to provide a theoretical account that can also work as a possible conceptual bridge between Synthetic Biology and Artificial Intelligence. In fact, we argue, Synthetic Biology can contribute to the study of minimal cognition (and therefore to a minimal AI), by providing a privileged approach to the study of these mechanisms by means of artificial systems. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Fecher, T.; Pail, R.; Gruber, T.
2017-05-01
GOCO05c is a gravity field model computed as a combined solution of a satellite-only model and a global data set of gravity anomalies. It is resolved up to degree and order 720. It is the first model applying regionally varying weighting. Since this causes strong correlations among all gravity field parameters, the resulting full normal equation system with a size of 2 TB had to be solved rigorously by applying high-performance computing. GOCO05c is the first combined gravity field model independent of EGM2008 that contains GOCE data of the whole mission period. The performance of GOCO05c is externally validated by GNSS-levelling comparisons, orbit tests, and computation of the mean dynamic topography, achieving at least the quality of existing high-resolution models. Results show that the additional GOCE information is highly beneficial in insufficiently observed areas, and that due to the weighting scheme of individual data the spectral and spatial consistency of the model is significantly improved. Due to usage of fill-in data in specific regions, the model cannot be used for physical interpretations in these regions.
Directory of Open Access Journals (Sweden)
Xi Ding
2014-01-01
Full Text Available Objective. The study was to investigate the impact of orthotropic material on the biomechanics of dental implant, based on a detailed mandible with high geometric and mechanical similarity. Materials and Methods. Multiple data sources were used to elaborate detailed biological structures and implant CAD models. In addition, an extended orthotropic material assignment methodology based on harmonic fields was used to handle the alveolar ridge region to generate compatible orthotropic fields. The influence of orthotropic material was compared with the commonly used isotropic model and simplified orthotropic model. Results. The simulation results showed that the values of stress and strain on the implant-bone interface almost increased in the orthotropic model compared to the isotropic case, especially for the cancellous bone. However, the local stress concentration was more obvious in the isotropic case compared to that in orthotropic case. The simple orthotropic model revealed irregular stress and strain distribution, compared to the isotropic model and the real orthotropic model. The influence of orthotropy was little on the implant, periodontal ligament, tooth enamel, and dentin. Conclusion. The orthotropic material has significant effect on stress and strain of implant-bone interface in the mandible, compared with the isotropic simulation. Real orthotropic mechanical properties of mandible should be emphasized in biomechanical studies of dental implants.
Lange, Julia; Weil, Frederik; Riegler, Christoph; Groeber, Florian; Rebhan, Silke; Kurdyn, Szymon; Alb, Miriam; Kneitz, Hermann; Gelbrich, Götz; Walles, Heike; Mielke, Stephan
2016-10-01
Human artificial skin models are increasingly employed as non-animal test platforms for research and medical purposes. However, the overall histopathological quality of such models may vary significantly. Therefore, the effects of manufacturing protocols and donor sources on the quality of skin models built-up from fibroblasts and keratinocytes derived from juvenile foreskins is studied. Histo-morphological parameters such as epidermal thickness, number of epidermal cell layers, dermal thickness, dermo-epidermal adhesion and absence of cellular nuclei in the corneal layer are obtained and scored accordingly. In total, 144 full-thickness skin models derived from 16 different donors, built-up in triplicates using three different culture conditions were successfully generated. In univariate analysis both media and donor age affected the quality of skin models significantly. Both parameters remained statistically significant in multivariate analyses. Performing general linear model analyses we could show that individual medium-donor-interactions influence the quality. These observations suggest that the optimal choice of media may differ from donor to donor and coincides with findings where significant inter-individual variations of growth rates in keratinocytes and fibroblasts have been described. Thus, the consideration of individual medium-donor-interactions may improve the overall quality of human organ models thereby forming a reproducible test platform for sophisticated clinical research.
Directory of Open Access Journals (Sweden)
Peter W Holder
Full Text Available Protecting a nation's primary production sector and natural estate is heavily dependent on the ability to determine the risk presented by incursions of exotic insect species. Identifying the geographic origin of such biosecurity breaches can be crucial in determining this risk and directing the appropriate operational responses and eradication campaigns, as well as ascertaining incursion pathways. Reading natural abundance biogeochemical markers using mass spectrometry is a powerful tool for tracing ecological pathways as well as provenance determination of commercial products and items of forensic interest. However, application of these methods to trace insects has been underutilised to date and our understanding in this field is still in a phase of basic development. In addition, biogeochemical markers have never been considered in the atypical situation of a biosecurity incursion, where sample sizes are often small, and of unknown geographic origin and plant host. These constraints effectively confound the interpretation of the one or two isotope geo-location markers systems that are currently used, which are therefore unlikely to achieve the level of provenance resolution required in biosecurity interceptions. Here, a novel approach is taken to evaluate the potential for provenance resolution of insect samples through multiple biogeochemical markers. The international pest, Helicoverpa armigera, has been used as a model species to assess the validity of using naturally occurring δ2H, 87Sr/86Sr, 207Pb/206Pb and 208Pb/206Pb isotope ratios and trace element concentration signatures from single moth specimens for regional assignment to natal origin. None of the biogeochemical markers selected were individually able to separate moths from the different experimental regions (150-3000 km apart. Conversely, using multivariate analysis, the region of origin was correctly identified for approximately 75% of individual H. armigera samples. The
Alligné, S.; Decaix, J.; Müller, A.; Nicolet, C.; Avellan, F.; Münch, C.
2016-11-01
Due to the massive penetration of alternative renewable energies, hydropower is a key energy conversion technology for stabilizing the electrical power network by using hydraulic machines at off design operating conditions. At full load, the axisymmetric cavitation vortex rope developing in Francis turbines acts as an internal source of energy, leading to an instability commonly referred to as selfexcited surge. 1-D models are developed to predict this phenomenon and to define the range of safe operating points for a hydropower plant. These models involve several parameters that have to be calibrated using experimental and numerical data. The present work aims to identify these parameters with URANS computations with a particular focus on the fluid damping rising when the cavitation volume oscillates. Two test cases have been investigated: a cavitation flow in a Venturi geometry without inlet swirl and a reduced scale model of a Francis turbine operating at full load conditions. The cavitation volume oscillation is forced by imposing an unsteady outlet pressure conditions. By varying the frequency of the outlet pressure, the resonance frequency is determined. Then, the pressure amplitude and the resonance frequency are used as two objectives functions for the optimization process aiming to derive the 1-D model parameters.
Abokifa, Ahmed A; Biswas, Pratim
2017-03-07
Partial replacement of lead service lines (LSLs) often results in the excessive long-term release of lead particulates due to the disturbance of pipe scale and galvanic corrosion. In this study, a modeling approach to simulate the release and transport of particulate and dissolved lead from full and partially replaced LSLs is developed. A mass-transfer model is coupled with a stochastic residential water demand generator to investigate the effect of normal household usage flow patterns on lead exposure. The model is calibrated by comparing simulation results against experimental measurements from pilot-scale setups where lead release under different flow rates and water chemistry scenarios was reported. Applying the model within a Monte Carlo simulation framework, partial replacement of the LSL was predicted to result in releasing spikes with significantly high concentrations of particulate lead (1011.9 ± 290.3 μg/L) that were five times higher than those released from the simulated full LSL. Sensitivity analysis revealed that the intensity of flow demands significantly affects particulate lead release, while dissolved lead levels are more dependent on the lengths of the stagnation periods. Preflushing of the LSL prior to regulatory sampling was found to underestimate the maximum monthly exposure to dissolved lead by 19%, while sampling at low flow rates (<5.2 LPM) was found to consistently suppress the high spikes induced by particulate lead mobilization.
Aaltonen, T; Álvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bisello, D; Bizjak, I; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Calamba, A; Calancha, C; Camarda, S; Campanelli, M; Campbell, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chung, W H; Chung, Y S; Ciocci, M A; Clark, A; Clarke, C; Compostella, G; Connors, J; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Crescioli, F; Cuevas, J; Culbertson, R; Dagenhart, D; d'Ascenzo, N; Datta, M; de Barbaro, P; Dell'Orso, M; Demortier, L; Deninno, M; Devoto, F; d'Errico, M; Di Canto, A; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Dorigo, M; Dorigo, T; Ebina, K; Elagin, A; Eppig, A; Erbacher, R; Errede, S; Ershaidat, N; Eusebi, R; Farrington, S; Feindt, M; Fernandez, J P; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Funakoshi, Y; Furic, I; Gallinaro, M; Garcia, J E; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Halkiadakis, E; Hamaguchi, A; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harr, R F; Hatakeyama, K; Hays, C; Heck, M; Heinrich, J; Herndon, M; Hewamanage, S; Hocker, A; Hopkins, W; Horn, D; Hou, S; Hughes, R E; Hurwitz, M; Husemann, U; Hussain, N; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kim, Y J; Kimura, N; Kirby, M; Klimenko, S; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Kruse, M; Krutelyov, V; Kuhr, T; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lecompte, T; Lee, E; Lee, H S; Lee, J S; Lee, S W; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lin, C-J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maeshima, K; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Martínez, M; Mastrandrea, P; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Mondragon, M N; Moon, C S; Moore, R; Morello, M J; Morlock, J; Movilla Fernandez, P; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Paramonov, A A; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Prokoshin, F; Pranko, A; Ptohos, F; Punzi, G; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Renton, P; Rescigno, M; Riddick, T; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sinervo, P; Sliwa, K; Smith, J R; Snider, F D; Soha, A; Sorin, V; Song, H; Squillacioti, P; Stancari, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thome, J; Thompson, G A; Thomson, E; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Varganov, A; Vázquez, F; Velev, G; Vellidis, C; Vidal, M; Vila, I; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wagner, R L; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Wick, F; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanetti, A; Zeng, Y; Zhou, C; Zucchelli, S
2012-11-02
A search is presented for the standard model Higgs boson produced in association with top quarks using the full Run II proton-antiproton collision data set, corresponding to 9.45 fb(-1), collected by the Collider Detector at Fermilab. No significant excess over the expected background is observed, and 95% credibility-level upper bounds are placed on the cross section σ(ttH → lepton + missing transverse energy+jets). For a Higgs boson mass of 125 GeV/c(2), we expect to set a limit of 12.6 and observe a limit of 20.5 times the standard model rate. This represents the most sensitive search for a standard model Higgs boson in this channel to date.
Aaltonen, T.
2012-01-01
A search is presented for the standard model Higgs boson produced in association with top quarks using the full Run II proton-antiproton collision data set, corresponding to 9.45 inverse fb, collected by the Collider Detector at Fermilab. No significant excess over the expected background is observed, and 95% credibility-level upper bounds are placed on the cross section sigma(t\\bar{t}H --> lepton + missing transverse energy + jets). For a Higgs boson mass of 125 GeV, we expect to set a limit of 12.6, and observe a limit of 20.5 times the standard model rate. This represents the most sensitive search for a standard model Higgs boson in this channel to date.
DEFF Research Database (Denmark)
Makda, Ishtiyaq Ahmed; Nymand, Morten
2015-01-01
This paper presents the common-mode noise analysis and modeling of a phase-shifted full-bridge forward converter. The common-mode noise source due to a transformer inter-winding capacitance is considered for the case of study. The generated common-mode noise voltage-source in a converter...... is analytically determined, which then leads to a common-mode noise modeling of a phase-shifted converter. Using a proposed model, common-mode noise-current harmonics are calculated and a fully analytical filter design procedure is presented to comply with the CISPR-11 standard. Finally, a prototype phase......-shifted forward converter is built to verify the theoretical analysis. This study shows that the primary-to-secondary transformer winding capacitance creates a very significant amount of common-mode noise current in a phase-shifted forward converter....
Balázs, András
2016-01-01
The Heisenberg-James-Stapp (quantum mechanical) mind model is surveyed and criticized briefly. The criticism points out that the model, while being essentially consistent concerning (human) consciousness, fundamentally lacks the evolutional point of view both onto- and phylogenetically. Ethology and other than Jamesian psychology is quoted and a quantum mechanical theoretical scheme is suggested to essentially extend Stapp's frame in an evolutionary context. It is proposed that its central supposition, spontaneous quantum measurement can be better utilized in an investigation of the origin of the "subjective" process, having come about concomitantly with the chemistry of the origin of life. We dwell on its applicability at this latter process, at its heart standing, it is supposed, the endophysical nonlinear "self-measurement" of (quantum mechanically describable) matter, and so our investigation is extended to this primeval phenomenon. It is suggested that the life phenomenon is an indirect C* → (W*) → C* quantum algebraic process transition, where the (W*) system would represent the living state. Summarized also are our previous results on an internalized, "reversed", time process, introduced originally by Gunji, which is subordinated to the external "forwards" time evolution, driving towards symmetry by gradual space-mappings, where the original splitting-up must have come about in a spontaneous symmetry breaking nonlinear "self-measurement" of matter in an endophysical World.
Politikos, D.; Somarakis, S.; Tsiaras, K. P.; Giannoulaki, M.; Petihakis, G.; Machias, A.; Triantafyllou, G.
2015-11-01
A 3-D full life cycle population model for the North Aegean Sea (NAS) anchovy stock is presented. The model is two-way coupled with a hydrodynamic-biogeochemical model (POM-ERSEM). The anchovy life span is divided into seven life stages/age classes. Embryos and early larvae are passive particles, but subsequent stages exhibit active horizontal movements based on specific rules. A bioenergetics model simulates the growth in both the larval and juvenile/adult stages, while the microzooplankton and mesozooplankton fields of the biogeochemical model provide the food for fish consumption. The super-individual approach is adopted for the representation of the anchovy population. A dynamic egg production module, with an energy allocation algorithm, is embedded in the bioenergetics equation and produces eggs based on a new conceptual model for anchovy vitellogenesis. A model simulation for the period 2003-2006 with realistic initial conditions reproduced well the magnitude of population biomass and daily egg production estimated from acoustic and daily egg production method (DEPM) surveys, carried out in the NAS during June 2003-2006. Model simulated adult and egg habitats were also in good agreement with observed spatial distributions of acoustic biomass and egg abundance in June. Sensitivity simulations were performed to investigate the effect of different formulations adopted for key processes, such as reproduction and movement. The effect of the anchovy population on plankton dynamics was also investigated, by comparing simulations adopting a two-way or a one-way coupling of the fish with the biogeochemical model.
Liu, Xiaoyu; Mason, Mark A.; Guo, Zhishi; Krebs, Kenneth A.; Roache, Nancy F.
2015-12-01
This paper describes the measurement and model evaluation of formaldehyde source emissions from composite and solid wood furniture in a full-scale chamber at different ventilation rates for up to 4000 h using ASTM D 6670-01 (2007). Tests were performed on four types of furniture constructed of different materials and from different manufacturers. The data were used to evaluate two empirical emission models, i.e., a first-order and power-law decay model. The experimental results showed that some furniture tested in this study, made only of solid wood and with less surface area, had low formaldehyde source emissions. The effect of ventilation rate on formaldehyde emissions was also examined. Model simulation results indicated that the power-law decay model showed better agreement than the first-order decay model for the data collected from the tests, especially for long-term emissions. This research was limited to a laboratory study with only four types of furniture products tested. It was not intended to comprehensively test or compare the large number of furniture products available in the market place. Therefore, care should be taken when applying the test results to real-world scenarios. Also, it was beyond the scope of this study to link the emissions to human exposure and potential health risks.
A Stochastic Model for Cancer Stem Cell Origin in Metastatic Colon Cancer
Odoux, Christine; Fohrer, Helene; Hoppo, Toshitaka; Guzik, Lynda; Stolz, Donna Beer; Lewis, Dale W.; Gollin, Susanne M.; Gamblin, T. Clark; Geller, David A.; Lagasse, Eric
2008-01-01
Human cancers have been found to include transformed stem cells that may drive cancer progression to metastasis. Here we report that metastatic colon cancer contains clonally derived tumor cells with all of the critical properties expected of stem cells, including self-renewal and to the ability to differentiate into mature colon cells. Additionally, when injected into mice, these cells initiated tumors that closely resemble human cancer. Karyotype analyses of parental and clonally-derived tumor cells expressed many consistent (clonal), along with unique chromosomal aberrations, suggesting the presence of chromosomal instability in the cancer stem cells. Thus, this new model for cancer origin and metastatic progression includes features of both the hierarchical model for cancerous stem cells and the stochastic model, driven by the observation of chromosomal instability. PMID:18757407
Testing modern human out-of-Africa dispersal models and implications for modern human origins.
Reyes-Centeno, Hugo; Hubbe, Mark; Hanihara, Tsunehiko; Stringer, Chris; Harvati, Katerina
2015-10-01
The modern human expansion process out of Africa has important implications for understanding the genetic and phenotypic structure of extant populations. While intensely debated, the primary hypotheses focus on either a single dispersal or multiple dispersals out of the continent. Here, we use the human fossil record from Africa and the Levant, as well as an exceptionally large dataset of Holocene human crania sampled from Asia, to model ancestor-descendant relationships along hypothetical dispersal routes. We test the spatial and temporal predictions of competing out-of-Africa models by assessing the correlation of geographical distances between populations and measures of population differentiation derived from quantitative cranial phenotype data. Our results support a model in which extant Australo-Melanesians are descendants of an initial dispersal out of Africa by early anatomically modern humans, while all other populations are descendants of a later migration wave. Our results have implications for understanding the complexity of modern human origins and diversity.
Parisi, Laura
2016-02-10
The surface wave full ray theory (FRT) is an efficient tool to calculate synthetic waveforms of surface waves. It combines the concept of local modes with exact ray tracing as a function of frequency, providing a more complete description of surface wave propagation than the widely used great circle approximation (GCA). The purpose of this study is to evaluate the ability of the FRT approach to model teleseismic long-period surface waveforms (T ∼ 45–150 s) in the context of current 3-D Earth models to empirically assess its validity domain and its scope for future studies in seismic tomography. To achieve this goal, we compute vertical and horizontal component fundamental mode synthetic Rayleigh waveforms using the FRT, which are compared with calculations using the highly accurate spectral element method. We use 13 global earth models including 3-D crustal and mantle structure, which are derived by successively varying the strength and lengthscale of heterogeneity in current tomographic models. For completeness, GCA waveforms are also compared with the spectral element method. We find that the FRT accurately predicts the phase and amplitude of long-period Rayleigh waves (T ∼ 45–150 s) for almost all the models considered, with errors in the modelling of the phase (amplitude) of Rayleigh waves being smaller than 5 per cent (10 per cent) in most cases. The largest errors in phase and amplitude are observed for T ∼ 45 s and for the three roughest earth models considered that exhibit shear wave anomalies of up to ∼20 per cent, which is much larger than in current global tomographic models. In addition, we find that overall the GCA does not predict Rayleigh wave amplitudes well, except for the longest wave periods (T ∼ 150 s) and the smoothest models considered. Although the GCA accurately predicts Rayleigh wave phase for current earth models such as S20RTS and S40RTS, FRT\\'s phase errors are smaller, notably for the shortest wave periods considered (T
Parisi, Laura; Ferreira, Ana M. G.
2016-04-01
The surface wave full ray theory (FRT) is an efficient tool to calculate synthetic waveforms of surface waves. It combines the concept of local modes with exact ray tracing as a function of frequency, providing a more complete description of surface wave propagation than the widely used great circle approximation (GCA). The purpose of this study is to evaluate the ability of the FRT approach to model teleseismic long-period surface waveforms (T ˜ 45-150 s) in the context of current 3-D Earth models to empirically assess its validity domain and its scope for future studies in seismic tomography. To achieve this goal, we compute vertical and horizontal component fundamental mode synthetic Rayleigh waveforms using the FRT, which are compared with calculations using the highly accurate spectral element method. We use 13 global earth models including 3-D crustal and mantle structure, which are derived by successively varying the strength and lengthscale of heterogeneity in current tomographic models. For completeness, GCA waveforms are also compared with the spectral element method. We find that the FRT accurately predicts the phase and amplitude of long-period Rayleigh waves (T ˜ 45-150 s) for almost all the models considered, with errors in the modelling of the phase (amplitude) of Rayleigh waves being smaller than 5 per cent (10 per cent) in most cases. The largest errors in phase and amplitude are observed for T ˜ 45 s and for the three roughest earth models considered that exhibit shear wave anomalies of up to ˜20 per cent, which is much larger than in current global tomographic models. In addition, we find that overall the GCA does not predict Rayleigh wave amplitudes well, except for the longest wave periods (T ˜ 150 s) and the smoothest models considered. Although the GCA accurately predicts Rayleigh wave phase for current earth models such as S20RTS and S40RTS, FRT's phase errors are smaller, notably for the shortest wave periods considered (T ˜ 45 s and
A unified gas-kinetic scheme for continuum and rarefied flows IV: Full Boltzmann and model equations
Liu, Chang; Xu, Kun; Sun, Quanhua; Cai, Qingdong
2016-06-01
Fluid dynamic equations are valid in their respective modeling scales, such as the particle mean free path scale of the Boltzmann equation and the hydrodynamic scale of the Navier-Stokes (NS) equations. With a variation of the modeling scales, theoretically there should have a continuous spectrum of fluid dynamic equations. Even though the Boltzmann equation is claimed to be valid in all scales, many Boltzmann solvers, including direct simulation Monte Carlo method, require the cell resolution to the order of particle mean free path scale. Therefore, they are still single scale methods. In order to study multiscale flow evolution efficiently, the dynamics in the computational fluid has to be changed with the scales. A direct modeling of flow physics with a changeable scale may become an appropriate approach. The unified gas-kinetic scheme (UGKS) is a direct modeling method in the mesh size scale, and its underlying flow physics depends on the resolution of the cell size relative to the particle mean free path. The cell size of UGKS is not limited by the particle mean free path. With the variation of the ratio between the numerical cell size and local particle mean free path, the UGKS recovers the flow dynamics from the particle transport and collision in the kinetic scale to the wave propagation in the hydrodynamic scale. The previous UGKS is mostly constructed from the evolution solution of kinetic model equations. Even though the UGKS is very accurate and effective in the low transition and continuum flow regimes with the time step being much larger than the particle mean free time, it still has space to develop more accurate flow solver in the region, where the time step is comparable with the local particle mean free time. In such a scale, there is dynamic difference from the full Boltzmann collision term and the model equations. This work is about the further development of the UGKS with the implementation of the full Boltzmann collision term in the region
Podboy, Gary G.; Bridges, James E.; Henderson, Brenda S.
2010-01-01
A 48-microphone planar phased array system was used to acquire jet noise source localization data on both a full-scale F404-GE-F400 engine and on a 1/4th scale model of a F400 series nozzle. The full-scale engine test data show the location of the dominant noise sources in the jet plume as a function of frequency for the engine in both baseline (no chevron) and chevron configurations. Data are presented for the engine operating both with and without afterburners. Based on lessons learned during this test, a set of recommendations are provided regarding how the phased array measurement system could be modified in order to obtain more useful acoustic source localization data on high-performance military engines in the future. The data obtained on the 1/4th scale F400 series nozzle provide useful insights regarding the full-scale engine jet noise source mechanisms, and document some of the differences associated with testing at model-scale versus fullscale.
Zbiciak, M.; Grabowik, C.; Janik, W.
2015-11-01
Nowadays the design constructional process is almost exclusively aided with CAD/CAE/CAM systems. It is evaluated that nearly 80% of design activities have a routine nature. These design routine tasks are highly susceptible to automation. Design automation is usually made with API tools which allow building original software responsible for adding different engineering activities. In this paper the original software worked out in order to automate engineering tasks at the stage of a product geometrical shape design is presented. The elaborated software works exclusively in NX Siemens CAD/CAM/CAE environment and was prepared in Microsoft Visual Studio with application of the .NET technology and NX SNAP library. The software functionality allows designing and modelling of spur and helicoidal involute gears. Moreover, it is possible to estimate relative manufacturing costs. With the Generator module it is possible to design and model both standard and non-standard gear wheels. The main advantage of the model generated in such a way is its better representation of an involute curve in comparison to those which are drawn in specialized standard CAD systems tools. It comes from fact that usually in CAD systems an involute curve is drawn by 3 points that respond to points located on the addendum circle, the reference diameter of a gear and the base circle respectively. In the Generator module the involute curve is drawn by 11 involute points which are located on and upper the base and the addendum circles therefore 3D gear wheels models are highly accurate. Application of the Generator module makes the modelling process very rapid so that the gear wheel modelling time is reduced to several seconds. During the conducted research the analysis of differences between standard 3 points and 11 points involutes was made. The results and conclusions drawn upon analysis are shown in details.
A COMPOUND MODEL FOR THE ORIGIN OF EARTH'S WATER
Energy Technology Data Exchange (ETDEWEB)
Izidoro, A.; Winter, O. C. [UNESP, Universidade Estadual Paulista, Grupo de Dinamica Orbital and Planetologia, Guaratingueta, CEP 12.516-410, Sao Paulo (Brazil); De Souza Torres, K. [UTFPR, Universidade Tecnologica Federal do Parana (Brazil); Haghighipour, N., E-mail: ocwinter@pq.cnpq.br [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii-Manoa, Honolulu, HI 96822 (United States)
2013-04-10
One of the most important subjects of debate in the formation of the solar system is the origin of Earth's water. Comets have long been considered as the most likely source of the delivery of water to Earth. However, elemental and isotopic arguments suggest a very small contribution from these objects. Other sources have also been proposed, among which local adsorption of water vapor onto dust grains in the primordial nebula and delivery through planetesimals and planetary embryos have become more prominent. However, no sole source of water provides a satisfactory explanation for Earth's water as a whole. In view of that, using numerical simulations, we have developed a compound model incorporating both the principal endogenous and exogenous theories, and investigating their implications for terrestrial planet formation and water delivery. Comets are also considered in the final analysis, as it is likely that at least some of Earth's water has cometary origin. We analyze our results comparing two different water distribution models, and complement our study using the D/H ratio, finding possible relative contributions from each source and focusing on planets formed in the habitable zone. We find that the compound model plays an important role by showing greater advantage in the amount and time of water delivery in Earth-like planets.
The fuel cell model of abiogenesis: a new approach to origin-of-life simulations.
Barge, Laura M; Kee, Terence P; Doloboff, Ivria J; Hampton, Joshua M P; Ismail, Mohammed; Pourkashanian, Mohamed; Zeytounian, John; Baum, Marc M; Moss, John A; Lin, Chung-Kuang; Kidd, Richard D; Kanik, Isik
2014-03-01
In this paper, we discuss how prebiotic geo-electrochemical systems can be modeled as a fuel cell and how laboratory simulations of the origin of life in general can benefit from this systems-led approach. As a specific example, the components of what we have termed the "prebiotic fuel cell" (PFC) that operates at a putative Hadean hydrothermal vent are detailed, and we used electrochemical analysis techniques and proton exchange membrane (PEM) fuel cell components to test the properties of this PFC and other geo-electrochemical systems, the results of which are reported here. The modular nature of fuel cells makes them ideal for creating geo-electrochemical reactors with which to simulate hydrothermal systems on wet rocky planets and characterize the energetic properties of the seafloor/hydrothermal interface. That electrochemical techniques should be applied to simulating the origin of life follows from the recognition of the fuel cell-like properties of prebiotic chemical systems and the earliest metabolisms. Conducting this type of laboratory simulation of the emergence of bioenergetics will not only be informative in the context of the origin of life on Earth but may help in understanding whether life might emerge in similar environments on other worlds.
Santabarbara, Ignacio; Haas, Edwin; Klatt, Steffen; Kiese, Ralf; Butterbach-Bahl, Klaus
2015-04-01
contributions. For the overall uncertainty quantification we calculated several thousand regional inventories with sampled model configurations, input datasets and parameter distributions. Statistical analysis of the regional simulation results have been used to quantify the overall full uncertainty of the inventory.
未来风格adidas Originals Blue Sneaker Model-4 Bit
Institute of Scientific and Technical Information of China (English)
铁铁
2011-01-01
adidas Originals Blue Sneaker Model-4 Bit融入日式街头式时尚潮流，鞋身设计具有超越现代感的未来风格。酷感简洁的纯白色高简鞋身设计，搭配标志性的三个魔术贴。清爽的风格和潮流感的全新设计专为具有时尚感的人士量身打造。
National Research Council Canada - National Science Library
Ignat Ignatov; Oleg Mosin
2015-01-01
We studied possible processes for origin of first chemoheterotrophic microorganisms with modeling of physiological processes of a Gram-positive chemoheterotrophic bacterium Bacillus subtilis, producer...
Directory of Open Access Journals (Sweden)
L. Zhao
2013-01-01
Full Text Available We investigate the impact of climate change on a small Tibetan glacier that is representative of the tens of thousands of mountain glaciers in the region. We apply a three-dimensional, thermo-mechanically coupled full-Stokes model to Gurenhekou Glacier located in the southern Tibetan Plateau. The steep and rugged geometry requires use of such a flow model to simulate the dynamical evolution of the glacier. We parameterize the temperature and mass balance using nearby automatic weather stations and an energy balance model for another glacier in the same mountain range. Summer air temperature increased at 0.02 K a^{−1} over the past 50 yr, and the glacier has retreated at an average rate of 8.3 m a^{−1}. Prognostic simulations suggest an accelerated retreating rate up to 14 m a^{−1} for the next 50 yr under continued steady warming, which is consistent with observed increased retreat in the last decade. However, regional climate models suggest a marked increase in warming rate over Tibet during the 21st century, and this rate causes about a 1% per year loss of glaciated area and glacier volume. These changes imply that this small glacier will probably disappear in a century. Although Tibetan glaciers are not particularly sensitive to climate warming, the rather high warming rates predicted by regional climate models combined with the small sizes of most Tibetan glaciers suggest that significant numbers of glaciers will be lost in the region during the 21st century.
Bellotti, Enrico; Wen, Hanqing; Pinkie, Benjamin; Matsubara, Masahiko; Bertazzi, Francesco
2015-08-01
Understanding the radiative and non-radiative properties of semiconductor materials is a prerequisite for optimizing the performance of existing light emitters and detectors and for developing new device architectures based on novel materials. Due to the ever increasing complexity of novel semiconductor systems and their relative technological immaturity, it is essential to have design tools and simulation strategies that include the details of the microscopic physics and their dependence on the macroscopic (continuum) variables in the macroscopic device models. Towards this end, we have developed a robust full-band structure based approach that can be used to study the intrinsic material radiative and non-radiative properties and evaluate the same characteristics of low-dimensional device structures. A parallel effort is being carried out to model the effect of substrate driven stress/strain and material quality (dislocations and defects) on microscopic quantities such as non-radiative recombination rate. Using this modeling approach, we have extensively studied the radiative and non-radiative properties of both elemental (Si and Ge) and compound semiconductors (HgCdTe, InGaAs, InAsSb and InGaN). In this work we outline the details of the modelling approach, specifically the challenges and advantages related to the use of the full-band description of the material electronic structure. We will present a detailed comparison of the radiative and Auger recombination rates as a function of temperature and doping for HgCdTe and InAsSb that are two important materials for infrared detectors and emitters. Furthermore we will discuss the role of non-radiatiave Auger recombination processes in explaining the performance of light emitter diodes. Finally we will present the extension of the model to low dimensional structures employed in a number of light emitter and detector structures.
A model for the origin of life through rearrangements among prebiotic phosphodiester polymers.
Yakhnin, Alexander V
2013-02-01
This model proposes that the origin of life on Earth occurred as a result of a process of alteration of the chemical composition of prebiotic macromolecules. The stability of organic compounds assembled into polymers generally exceeded the stability of the same compounds as free monomers. This difference in stability stimulated accumulation of prebiotic macromolecules. The prebiotic circulation of matter included constant formation and decomposition of polymers. Spontaneous chemical reactions between macromolecules with phosphodiester backbones resulted in a non-Darwinian selection for chemical stability, while formation of strong structures provided an advantage in the struggle for stability. Intermolecular structures between nucleotide-containing polymers were further stabilized by occasional acquisition of complementary nucleotides. Less stable macromolecules provided the source of nucleotides. This process resulted first in the enrichment of nucleotide content in prebiotic polymers, and subsequently in the accumulation of complementary oligonucleotides. Finally, the role of complementary copy molecules changed from the stabilization of the original templates to the de novo production of template-like molecules. I associate this stage with the origin of life in the form of cell-free molecular colonies. Original life acquired ready-to-use substrates from constantly forming prebiotic polymers. Metabolism started to develop when life began to consume more substrates than the prebiotic cycling produced. The developing utilization of non-polymeric compounds stimulated the formation of the first membrane-enveloped cells that held small soluble molecules. Cells "digested" the nucleotide-containing prebiotic macromolecules to nucleotide monomers and switched the mode of replication to the polymerization of nucleotide triphosphates.
Calculations of 3D full-scale VVER fuel assembly and core models using MCU and BIPR-7A codes
Energy Technology Data Exchange (ETDEWEB)
Aleshin, Sergey S.; Bikeev, Artem S.; Bolshagin, Sergey N.; Kalugin, Mikhail A.; Kosourov, Evgeniy K.; Pavlovichev, Aleksandr M.; Pryanichnikov, Aleksandr V.; Sukhino-Khomenko, Evgenia A.; Shcherenko, Anna I.; Shcherenko, Anastasia I.; Shkarovskiy, Denis A. [Nuclear Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation)
2015-09-15
Two types of calculations were made to compare BIPR-7A and MCU results for 3D full-scale models. First EPS (emergency protection system) efficiency and in-core power distributions were analyzed for an equilibrium fuel load of VVER-1000 assuming its operation within an 18-month cycle. Computations were performed without feedbacks and with fuel burnup distributed over the core. After 3D infinite lattices of full-scale VVER-1000 fuel assemblies (A's) with uranium fuel 4.4% enrichment and uranium-erbium fuel 4.4% enrichment and Er{sub 2}O{sub 3} 1 % wt were considered. Computations were performed with feedbacks and fuel burnup at the constant power level. For different time moments effective multiplication factor and power distribution were obtained. EPS efficiency and reactivity effects at chosen time moments were analyzed.
DEFF Research Database (Denmark)
Hansen, Stine Broholm; Jensen, Peter Arendt; Jappe Frandsen, Flemming
2017-01-01
describes particle sticking or rebound by a combination of the description of (visco)elsatic particles impacting a solid surface and particle capture by a viscous surface. The model is used to predict deposit formation rates measured during tests conducted with probes in full-scale suspension-fired biomass...... of some physical parameters related to the description of surface capture are suggested. Based on these examinations of the model ability to describe observed deposit formation rates, the proposed model can be regarded as a promising tool for description of deposit formation in full-scale biomass......A model for deposit formation in suspension firing of biomass has been developed. The model describes deposit build-up by diffusion and subsequent condensation of vapors, thermoforesis of aerosols, convective diffusion of small particles, impaction of large particles and reaction. The model...
Huang, Diana D; Foley, Brian T; Tolzmann, Catlin A; Ouma, Annastasia; Bremer, James W
2009-10-01
Sequence characterization of the near full-length genomes of HIV-1 isolates BCF-Dioum and BCF-Kita, originating from the Democratic Republic of Congo (DRC), was continued. These NED panel isolates, contributed by F. Brun-Vezinet (ENVA-France), were first identified as subtypes G and H, respectively. Our earlier analyses of portions of their pol genes showed that both were likely to be intersubtype recombinants of different composition. This study analyzed the remainder of each genome, confirming them to be complex recombinants. The BCF-Dioum genome resembles CRF06_cpx strains found in West Africa, composed of subtypes A/G/J/K. The BCF-Kita genome is a unique complex recombinant A-F-G-H-K-U strain. These data support previous observations of the complexity of strains originating from the DRC. BCF-Dioum may be a suitable strain for standards and reagents since it matches a defined circulating recombinant form. Studies and reagents made from BCF-Kita should take into account its complex genome.
Directory of Open Access Journals (Sweden)
Caitlyn eCollins
2015-09-01
Full Text Available Objective: This study was performed in order to determine if mathematical modeling of the canine teeth in dogs could be utilized to provide an accurate and reliable estimation of crown surface area that could be used in both a research and clinical setting.Materials and methods: Actual surface area (aSA calculations for 32 stone dies of clinical crown preparations were acquired utilizing a tridimensional (3D laser scanner and 3D computer-aided design and manufacturing (CAD/CAM software applications. These calculations were used as a control. Seventeen unique mathematical models from 8 geometric shapes were used to calculate estimated surface area (eSA of each stone die. Linear association and agreement between eSA and aSA calculations were assessed with multiple statistical methods. Results: All methods of eSA showed a significant linear association with aSA. Five of the mathematical models [right elliptical frustum (H3, right elliptical cone (G3, right pyramidal cone (A3, right circular frustum (F2 and right circular cone (E1] were superior to the other 12 models.Conclusions: The H3 mathematical model based on the right elliptical frustum provided the most accurate estimate of crown surface area of dog teeth. However, H3 requires the use of laser scans and a 3D CAD software program. As a result, this model would be recommended for research applications. The E1 mathematical model was similar in accuracy to H3 and, given it requires only two measurements and a comparatively simple equation for calculation, this method would be recommended for clinical chair-side use.
Simulating Ice-Flow and Calving on Store Glacier, West Greenland, with a 3D Full Stokes Model
Todd, J.; Christoffersen, P.; Zwinger, T.; Luckman, A. J.; Benn, D.
2015-12-01
The mass balance and long-term stability of the ice sheets in Greenland and Antarctica depend heavily on the dynamics of their ice-ocean margins. Iceberg calving accounts for the majority of the net annual loss of ice in Antarctica and around half of that from Greenland. Furthermore, climate driven changes to dynamics at these calving margins can be transmitted far inland. Thus, predicting future sea level contribution from the cryosphere requires an improved understanding of calving, and the processes which link it to climate and ice-sheet flow. We present results from a new 3D calving model coupled to a full-Stokes, time evolving glacier dynamic model, implemented for Store Glacier, a 5-km-wide calving glacier in the Uummannaq region of West Greenland, which flows at a rate of 20 m/day at its terminus. The model is developed using the open source finite element package Elmer/Ice, with the criterion that calving occurs when surface and basal crevasses meet. Crevasses open in response to tensile stresses near the terminus and water pressure at the bed. When the model was applied in 2D for the central flowline of Store Glacier, we found that basal topography exerts overarching control on the long term position of the calving front, while ice mélange buttressing allows the seasonal extension of a floating tongue, which collapses in early summer. New results emerging from implementation of calving in a 3D model indicate significant spatial heterogeneity in calving dynamics because the northern half of the terminus is grounded whereas the southern half is floating. This contrasting setting affects calving dynamics, further underlining the importance of geometry and basal topography, and suggesting that lower dimensional calving models may miss important aspects of calving dynamics. Our results also suggest that implementing grounding line dynamics is important for modelling calving, even for glaciers which are, for the most part, firmly grounded.
Yang, Zili
2017-07-01
Heart segmentation is an important auxiliary method in the diagnosis of many heart diseases, such as coronary heart disease and atrial fibrillation, and in the planning of tumor radiotherapy. Most of the existing methods for full heart segmentation treat the heart as a whole part and cannot accurately extract the bottom of the heart. In this paper, we propose a new method based on linear gradient model to segment the whole heart from the CT images automatically and accurately. Twelve cases were tested in order to test this method and accurate segmentation results were achieved and identified by clinical experts. The results can provide reliable clinical support.
Türkay, Semiha; Akçay, Hüseyin
2014-03-01
This paper studies multi-objective control of a full-vehicle suspension excited by random road disturbances. The control problem is first formulated as a mixed ℋ2/ℋ∞ synthesis problem and an output-feedback solution is obtained by using linear-matrix-inequalities. Next, the multi-objective control problem is re-formulated as a non-convex and non-smooth optimisation problem with controller order restricted to be less than the vehicle model order. For a range of orders, controllers are synthesised by using the HIFOO toolbox. The efficacy of the presented procedures are demonstrated by several design examples.
DEFF Research Database (Denmark)
Ko, Youngjong; Park, Kiwoo; Lee, Kyo-Beum;
2011-01-01
into fundamental and harmonic components and a virtual phase voltage is generated from the fundamental component using a Full Order Observer (FOO). Two virtual voltages are used as an input for the PLL system so the phase angle errors can be reduced and the output power quality can be improved. The dynamic...... characteristics of the PLL system are designed using the modeling method to improve the dynamic response and stability of the whole system. The performance of the proposed method has been verified by a comparative analysis to the conventional PLL system. It is concluded the proposed method works well....
DURAK, Halil; GENEL, Yasar; BASHIROV, Novruz; KERIMOV, Genber
2013-01-01
Ulexite is a sodium calcium boron hydrate used in producing compounds, its chemical formula is Na2O2CaO5B2O3.16H2O, and it superabounds in Turkey. One of the significant boron compounds derived from boron minerals is boric acid. The aim of this study is producing boric acid in the wake of interaction of ulexite with hydrochloric acid solution, and offering an alternative process to producing boric acid by forming the mathematical model of this processing. Full factorial de...
Kenow, Kevin P.; Ge, Zhongfu; Fara, Luke J.; Houdek, Steven C.; Lubinski, Brian R.
2016-01-01
Avian botulism type E is responsible for extensive waterbird mortality on the Great Lakes, yet the actual site of toxin exposure remains unclear. Beached carcasses are often used to describe the spatial aspects of botulism mortality outbreaks, but lack specificity of offshore toxin source locations. We detail methodology for developing a neural network model used for predicting waterbird carcass motions in response to wind, wave, and current forcing, in lieu of a complex analytical relationship. This empirically trained model uses current velocity, wind velocity, significant wave height, and wave peak period in Lake Michigan simulated by the Great Lakes Coastal Forecasting System. A detailed procedure is further developed to use the model for back-tracing waterbird carcasses found on beaches in various parts of Lake Michigan, which was validated using drift data for radiomarked common loon (Gavia immer) carcasses deployed at a variety of locations in northern Lake Michigan during September and October of 2013. The back-tracing model was further used on 22 non-radiomarked common loon carcasses found along the shoreline of northern Lake Michigan in October and November of 2012. The model-estimated origins of those cases pointed to some common source locations offshore that coincide with concentrations of common loons observed during aerial surveys. The neural network source tracking model provides a promising approach for identifying locations of botulinum neurotoxin type E intoxication and, in turn, contributes to developing an understanding of the dynamics of toxin production and possible trophic transfer pathways.
Nantasenamat, Chanin; Simeon, Saw; Owasirikul, Wiwat; Songtawee, Napat; Lapins, Maris; Prachayasittikul, Virapong; Wikberg, Jarl E S
2014-10-15
Green fluorescent protein (GFP) has immense utility in biomedical imaging owing to its autofluorescent nature. In efforts to broaden the spectral diversity of GFP, there have been several reports of engineered mutants via rational design and random mutagenesis. Understanding the origins of spectral properties of GFP could be achieved by means of investigating its structure-activity relationship. The first quantitative structure-property relationship study for modeling the spectral properties, particularly the excitation and emission maximas, of GFP was previously proposed by us some years ago in which quantum chemical descriptors were used for model development. However, such simplified model does not consider possible effects that neighboring amino acids have on the conjugated π-system of GFP chromophore. This study describes the development of a unified proteochemometric model in which the GFP chromophore and amino acids in its vicinity are both considered in the same model. The predictive performance of the model was verified by internal and external validation as well as Y-scrambling. Our strategy provides a general solution for elucidating the contribution that specific ligand and protein descriptors have on the investigated spectral property, which may be useful in engineering novel GFP variants with desired characteristics.
Alligné, S.; Decaix, J.; Müller, A.; Nicolet, C.; Avellan, F.; Münch, C.
2017-04-01
Due to the massive penetration of alternative renewable energies, hydropower is a key energy conversion technology for stabilizing the electrical power network by using hydraulic machines at off design operating conditions. At full load, the axisymmetric cavitation vortex rope developing in Francis turbines acts as an internal source of energy, leading to an instability commonly referred to as self-excited surge. 1-D models are developed to predict this phenomenon and to define the range of safe operating points for a hydropower plant. These models require a calibration of several parameters. The present work aims at identifying these parameters by using CFD results as objective functions for an optimization process. A 2-D Venturi and 3-D Francis turbine are considered.
Tik, Sovanna; Vanrolleghem, Peter A
2017-03-01
Chemically enhanced primary treatment (CEPT) can be used to mitigate the adverse effect of wet weather flow on wastewater treatment processes. In particular, it can reduce the particulate pollution load to subsequent secondary unit processes, such as biofiltration, which may suffer from clogging by an overload of particulate matter. In this paper, a simple primary clarifier model able to take into account the effect of the addition of chemicals on particle settling is presented. Control strategies that optimize the treatment process by chemical addition were designed and tested by running simulations with this CEPT model. The most adequate control strategy in terms of treatment performance, chemicals saving, and maintenance effort was selected. Full-scale implementation of the controller was performed during the autumn of 2015, and the results obtained confirmed the behaviour of the controlled system. Practical issues related to the implementation are presented.
Directory of Open Access Journals (Sweden)
H. Seddik
2011-06-01
Full Text Available A three-dimensional, thermo-mechanically coupled ice flow model with induced anisotropy has been applied to a ~200 × 200 km domain around the Dome Fuji drill site, Antarctica. The model ("Elmer/Ice" is based on the open-source multi-physics package Elmer (
Directory of Open Access Journals (Sweden)
H. Seddik
2009-01-01
Full Text Available A three-dimensional, thermo-mechanically coupled ice flow model with induced aniso-tropy has been applied to a ~200×200 km domain around the Dome Fuji drill site, Antarctica. The model ("Elmer/Ice" is based on the open-source multi-physics package Elmer (http://www.csc.fi/elmer/ and solves the full-Stokes equations. Flow-induced anisotropy in ice is accounted for by an implementation of the Continuum-mechanical, Anisotropic Flow model, based on an anisotropic Flow Enhancement factor ("CAFFE model". Steady-state simulations for present-day climate conditions are conducted. The main findings are: (i the flow regime at Dome Fuji is a complex superposition of vertical compression, horizontal extension and bed-parallel shear; (ii for a geothermal heat flux of 60 mW m^{−2} the basal temperature at Dome Fuji reaches the pressure melting point and the basal melting rate is ~1 mm a^{−1}; (iii the fabric shows a weak single maximum at Dome Fuji, which increases the age of the ice compared to an isotropic scenario; (iv as a consequence of spatially variable basal melting conditions, and contrary to intuition, the basal age is smaller where the ice is thicker and larger where the ice is thinner. The latter result is of great relevance for the consideration of a future drill site in the area.
成本建模与原价分析%Cost Modeling and Original Price Analysis
Institute of Scientific and Technical Information of China (English)
王涛; 袁建新
2015-01-01
In the light of the processing characteristics of automotive sheet metal parts, and based on the establishment of the homogeneous cost pool, we construct the mathematical model of sheet metal products’ original price.By using the models, we make the original price analysis and carry out the sheet metal products’ actuarial work, so the cost control point is found, and ultimately it is realized to save procurement costs and reduce the purchase price.%根据汽车钣金件加工特点，在建立同质作业成本库的基础上，对钣金件产品原价进行数学模型构建，通过模型的运用，实现钣金件产品原价的分析与精算工作，从而发现成本控制点，最终达到节约采购成本、降低采购价格的目的。
A new theoretical model for the origin of amino acid homochirality
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Amino acid homochirality, as a unique behavior of life, could have originated synchronously with the genetic code. In this paper, phosphoryl amino-acid -5'-nucleosides with P-N bond are postulated to be a chiral origin model in prebiotic molecular evolution. The enthalpy change in the intramolecular interaction between the nucleotide base and the amino-acid side-chain determines the stability of the particular complex, resulting in a preferred conformation associated with the chirality of amino acids. Based on the theoretical model, our experiments and calculations show that the chiral selection of the earliest amino acids for L-enantiomers seems to be a strict stereochemical/physicochemical determinism. As other amino acids developed biosynthetically from the earliest amino acids, we infer that the chirality of the later amino acids was inherited from the precursor amino acids. This idea probably goes far back in history, but it is hoped that it will be a guide for further experiments in this area.
van Hooft, Paul A. M.; Höltje, Hans-Dieter
2000-11-01
A new method is described for generating all-atom protein structures from Cα-atom information. The method, which combines both local structural trace alignments and comparative side chain modeling with ab initio side chain modeling, makes use of both the virtual-bond and the dipole-path methods. Provided that 3D structures of structurally and functionally related proteins exist, the method presented here is highly suitable for generating all-atom coordinates of partly solved, low-resolution crystal structures. Particularly the active site region can be modeled accurately with this procedure, which enables investigation of the binding modes of different classes of ligands with molecular dynamics simulations. The method is applied to the trace of Streptococcus pneumoniae, in order to construct an all-atom structure of the transpeptidase domain. Since after generation of full coordinates of the transpeptidase domain the structure had been solved to 2.4 Å resolution, new X-ray coordinates for the worst modeled loop (residues T370 to M386; 17 out of a total number of 351 residues constituting the transpeptidase domain) were incorporated, as kindly provided by Dr. Dideberg. The structure was relaxed with molecular dynamics simulations and simulated annealing methods. The RMS deviation between the 144 aligned Cα-atoms and the corresponding ones in the originally solved 3.5 Å resolution crystal structure was 0.98. The 351 Cα-atoms of the whole transpeptidase domain of the final model showed an RMS deviation of 1.58. The Ramachandran plot showed that 79.3% of the residues are in the most favored regions, with only 1.0% occurring in disallowed regions. The model presented here can be used to investigate the three-dimensional influences of mutations around the active site of PBP2 x.
Suh, Chang-Won; Lee, Joong-Won; Hong, Yoon-Seok Timothy; Shin, Hang-Sik
2009-01-01
We propose an evolutionary process model induction system that is based on the grammar-based genetic programming to automatically discover multivariate dynamic inference models that are able to predict fecal coliform bacteria removals using common process variables instead of directly measuring fecal coliform bacteria concentration in a full-scale municipal activated-sludge wastewater treatment plant. A sequential modeling paradigm is also proposed to derive multivariate dynamic models of fecal coliform removals in the evolutionary process model induction system. It is composed of two parts, the process estimator and the process predictor. The process estimator acts as an intelligent software sensor to achieve a good estimation of fecal coliform bacteria concentration in the influent. Then the process predictor yields sequential prediction of the effluent fecal coliform bacteria concentration based on the estimated fecal coliform bacteria concentration in the influent from the process estimator with other process variables. The results show that the evolutionary process model induction system with a sequential modeling paradigm has successfully evolved multivariate dynamic models of fecal coliform removals in the form of explicit mathematical formulas with high levels of accuracy and good generalization. The evolutionary process model induction system with sequential modeling paradigm proposed here provides a good alternative to develop cost-effective dynamic process models for a full-scale wastewater treatment plant and is readily applicable to a variety of other complex treatment processes.
Ferrighi, Lara; Marchesan, Domenico; Ruud, Kenneth; Frediani, Luca; Coriani, Sonia
2005-11-01
We present an implementation of the polarizable continuum model in its integral equation formulation for the calculation of the magnetizabilities of solvated molecules. The gauge-origin independence of the calculated magnetizabilities and the fast basis set convergence are ensured through the use of London atomic orbitals. Our implementation can use Hartree-Fock and multiconfigurational self-consistent-field (MCSCF) wave functions as well as density-functional theory including hybrid functionals such as B3LYP. We present the results of dielectric continuum effects on water and pyridine using MCSCF wave functions, as well as dielectric medium effects on the magnetizability of the aromatic amino acids as a model for how a surrounding protein environment affects the magnetizability of these molecules. It is demonstrated that the dielectric medium effects on the magnetizability anisotropies of the aromatic amino acids may be substantial, being as large as 25% in the case of tyrosine.
Merker, L.; Weichselbaum, A.; Costi, T. A.
2012-08-01
Recent developments in the numerical renormalization group (NRG) allow the construction of the full density matrix (FDM) of quantum impurity models [see A. Weichselbaum and J. von Delft, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.99.076402 99, 076402 (2007)] by using the completeness of the eliminated states introduced by F. B. Anders and A. Schiller [F. B. Anders and A. Schiller, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.95.196801 95, 196801 (2005)]. While these developments prove particularly useful in the calculation of transient response and finite-temperature Green's functions of quantum impurity models, they may also be used to calculate thermodynamic properties. In this paper, we assess the FDM approach to thermodynamic properties by applying it to the Anderson impurity model. We compare the results for the susceptibility and specific heat to both the conventional approach within NRG and to exact Bethe ansatz results. We also point out a subtlety in the calculation of the susceptibility (in a uniform field) within the FDM approach. Finally, we show numerically that for the Anderson model, the susceptibilities in response to a local and a uniform magnetic field coincide in the wide-band limit, in accordance with the Clogston-Anderson compensation theorem.
Zhang, Jie; Tejada-Martínez, Andrés E; Zhang, Qiong; Lei, Hongxia
2014-04-01
The capability of predicting hydraulic and disinfection efficiencies of ozone disinfection contactors is essential for evaluating existing contactors and improving future designs. Previous attempts based on ideal and non-ideal models for the hydraulics and simplified mechanisms for chemical reaction modeling have resulted in low accuracy and are restricted to contactors with simple geometries. This manuscript develops a modeling framework for the ozonation process by combining computational fluid dynamics (CFD) with a kinetics-based reaction modeling for the first time. This computational framework has been applied to the full-scale ozone contactor operated by the City of Tampa Water Department. Flow fields, residence time distribution, ozone concentration distribution, and concentration-contact time (CT) distribution within the contactor have been predicted via the computational framework. The predictions of ozone and bromate concentrations at sample points agree well with physical experimental data measured in the contactor. The predicted CT values at the contactor outlet demonstrate that the disinfection performance of the ozone contactor operated by the City of Tampa Water Department is sufficient to meet regulation requirements. The impact of seasonal flow rate change on disinfection performance is found to be significant and deserves attention during the management and operation of a water treatment plant.
Directory of Open Access Journals (Sweden)
Ignat Ignatov
2015-09-01
Full Text Available We studied possible processes for origin of first chemoheterotrophic microorganisms with modeling of physiological processes of a Gram-positive chemoheterotrophic bacterium Bacillus subtilis, producer of purine ribonucleoside inosine as a model system in heavy water. The physiological influence of deuterium on the chemoheterotrophic bacterium B. subtilis was studied on a heavy water (HW medium with a maximal concentration of 2H2O (89–90 atom% 2H. Also various suitable samples of hot mineral water and sea water derived from different sources of Bulgaria were investigated using IR- and DNES-spectroscopy. It was shown that hot alkaline mineral water with temperature from +65 0C to +95 0C and pH value from 9 to 11 is more suitable for the origination of first organic forms than other analyzed water samples. There were discussed the reactions of condensation and dehydration occurring in alkaline aqueous solutions at t = +65–95 0C and рН = 9–10, resulting in synthesis from separate molecules the larger organic molecules as short polipeptides and pyrines, as well as the possible mechanisms of the deuterium accumulation in form of H2HO in hot water. The metabolism of the bacterium B. subtilis and the resistance to deuterium was also analyzed on an evolutionary level taking into account the hydrological conditions of primodial hydrosphere and the presence of H2HO, as well as the qualitative and quantitative composition of the cellular protein, amino acids and carbohydrates on media with maximum deuterium content. It was demonstrated on the example of chemoheterotrophic bacteria that first microorganisms might have been originated in hot mineral water with Ca2+ (0.5-1.0 g/l at t = + 65-95 0C and pH = 9–11, that is more suitable for maintenance and origin of life than other analyzed water samples.
Qiu, Lei; Yuan, Shenfang; Bao, Qiao; Mei, Hanfei; Ren, Yuanqiang
2016-05-01
For aerospace application of structural health monitoring (SHM) technology, the problem of reliable damage monitoring under time-varying conditions must be addressed and the SHM technology has to be fully validated on real aircraft structures under realistic load conditions on ground before it can reach the status of flight test. In this paper, the guided wave (GW) based SHM method is applied to a full-scale aircraft fatigue test which is one of the most similar test status to the flight test. To deal with the time-varying problem, a GW-Gaussian mixture model (GW-GMM) is proposed. The probability characteristic of GW features, which is introduced by time-varying conditions is modeled by GW-GMM. The weak cumulative variation trend of the crack propagation, which is mixed in time-varying influence can be tracked by the GW-GMM migration during on-line damage monitoring process. A best match based Kullback-Leibler divergence is proposed to measure the GW-GMM migration degree to reveal the crack propagation. The method is validated in the full-scale aircraft fatigue test. The validation results indicate that the reliable crack propagation monitoring of the left landing gear spar and the right wing panel under realistic load conditions are achieved.
Atucha II NPP full scope simulator modelling with the thermal hydraulic code TRAC{sub R}T
Energy Technology Data Exchange (ETDEWEB)
Alonso, Pablo Rey; Ruiz, Jose Antonio; Rivero, Norberto, E-mail: prey@tecnatom.e, E-mail: jaruiz@tecnatom.e, E-mail: nrivero@tecnatom.e [Tecnatom S.A., Madrid (Spain)
2011-07-01
In February 2010 NA-SA (Nucleoelectrica Argentina S.A.) awarded Tecnatom the Atucha II full scope simulator project. NA-SA is a public company owner of the Argentinean nuclear power plants. Atucha II is due to enter in operation shortly. Atucha II NPP is a PHWR type plant cooled by the water of the Parana River and has the same design as the Atucha I unit, doubling its power capacity. Atucha II will produce 745 MWe utilizing heavy water as coolant and moderator, and natural uranium as fuel. A plant singular feature is the permanent core refueling. TRAC{sub R}T is the first real time thermal hydraulic six-equations code used in the training simulation industry for NSSS modeling. It is the result from adapting to real time the best estimate code TRACG. TRAC{sub R}T is based on first principle conservation equations for mass, energy and momentum for liquid and steam phases, with two phase flows under non homogeneous and non equilibrium conditions. At present, it has been successfully implemented in twelve full scope replica simulators in different training centers throughout the world. To ease the modeling task, TRAC{sub R}T includes a graphical pre-processing tool designed to optimize this process and alleviate the burden of entering alpha numerical data in an input file. (author)
A model of accumulation of radionuclides in biosphere originating from groundwater contamination
Energy Technology Data Exchange (ETDEWEB)
Gaerdenaes, Annemieke [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Soil Sciences; Jansson, Per-Erik; Karlberg, Louise [Royal Inst. of Technology, Stockholm (Sweden). Dept. Land and Water Resources
2006-03-15
The objective of this study is to introduce a module in CoupModel describing the transport and accumulation in the biosphere of a radionuclide originating from a ground water contamination. Two model approaches describing the plant uptake of a radionuclide were included, namely passive and active uptake. Passive uptake means in this study that the root uptake rate of a radionuclide is governed by water uptake. Normal mechanism for the passive water uptake is the convective flux of water from the soil to the plant. An example of element taken up passively is Ca. Active plant uptake is in this model defined as the root uptake rate of a radionuclide that is governed by carbon assimilation i.e. photosynthesis and plant growth. The actively taken up element can for example be an element essential to plant, but not available in high enough concentration by passive uptake alone, like the major nutrients N and P or an element that very well resembles a plant nutrient, like Cs resembles K. Active uptake of trace element may occur alone or in addition to passive uptake. Normal mechanism for the active uptake is molecular diffusion from the soil solution to the roots or via any other organism living in symbiosis with the roots like the mycorrhiza. Also a model approach describing adsorption was introduced. CoupModel dynamically couples and simulates the flows of water, heat, carbon and nitrogen in the soil/plant/atmosphere system. Any number of plants may be defined and are divided into roots, leaves, stem and grain. The soil is considered in one vertical profile that may be represented into a maximum of 100 layers. The model is the windows-successor and integrated version of the DOS-models SOIL and SOILN, which have been widely used on different ecosystems and climate regions during 25 years time period. To this soil/plant/atmosphere model were introduced a module describing accumulation of a radionuclide in the biosphere originating from groundwater contamination. The
Rohmer, Jeremy; Idier, Deborah; Bulteau, Thomas; Paris, François
2016-04-01
From a risk management perspective, it can be of high interest to identify the critical set of offshore conditions that lead to inundation on key assets for the studied territory (e.g., assembly points, evacuation routes, hospitals, etc.). This inverse approach of risk assessment (Idier et al., NHESS, 2013) can be of primary importance either for the estimation of the coastal flood hazard return period or for constraining the early warning networks based on hydro-meteorological forecast or observations. However, full-process based models for coastal flooding simulation have very large computational time cost (typically of several hours), which often limits the analysis to a few scenarios. Recently, it has been shown that meta-modelling approaches can efficiently handle this difficulty (e.g., Rohmer & Idier, NHESS, 2012). Yet, the full-process based models are expected to present strong non-linearities (non-regularities) or shocks (discontinuities), i.e. dynamics controlled by thresholds. For instance, in case of coastal defense, the dynamics is characterized first by a linear behavior of the waterline position (increase with increasing offshore conditions), as long as there is no overtopping, and then by a very strong increase (as soon as the offshore conditions are energetic enough to lead to wave overtopping, and then overflow). Such behavior might make the training phase of the meta-model very tedious. In the present study, we propose to explore the feasibility of active learning techniques, aka semi-supervised machine learning, to track the set of critical conditions with a reduced number of long-running simulations. The basic idea relies on identifying the simulation scenarios which should both reduce the meta-model error and improve the prediction of the critical contour of interest. To overcome the afore-described difficulty related to non-regularity, we rely on Support Vector Machines, which have shown very high performance for structural reliability
Longitudinal and Integrative Tests of Family Stress Model Effects on Mexican-Origin Adolescents
White, Rebecca M. B.; Liu, Yu; Nair, Rajni L.; Tein, Jenn-Yun
2015-01-01
The family stress model represents a common framework through which to examine the effects of environmental stressors on adolescent adjustment. The model suggests that economic and neighborhood stressors influence youth adjustment via disruptions to parenting. Incorporating integrative developmental theory, we examined the degree to which parents’ cultural value orientations mitigated the effects of stressors on parenting disruptions and the degree to which environmental adversity qualified the effect of parenting on adolescent adjustment. We tested the hypothesized Integrative Family Stress Model longitudinally in a sample of mother-youth dyads (N = 749) and father-youth dyads (N = 467) from Mexican origin families, across three times points spanning early to middle adolescence. Providing the first longitudinal evidence of family stress mediated effects, mothers’ perceptions of economic pressure were associated with increases in adolescent externalizing symptoms five years later via intermediate increases in harsh parenting. The remaining findings supported the notion that integrative developmental theory can inform family stress model hypothesis testing that is culturally and contextually relevant for wide range of diverse families and youth. For example, fathers’ perceptions of economic pressure and neighborhood danger had important implications for adolescent internalizing, via reductions in paternal warmth, but only at certain levels of neighborhood adversity. Mothers’ familism value orientations mitigated the effects of economic pressure on maternal warmth, protecting their adolescents from experiencing developmental costs associated with environmental stressors. Results are discussed in terms of identifying how integrative developmental theory intersects with the family stress model to set diverse youth on different developmental pathways. PMID:25751100
A two-dimensional CA model for traffic flow with car origin and destination
In-nami, Junji; Toyoki, Hiroyasu
2007-05-01
Dynamic phase transitions in a two-dimensional traffic flow model defined on a decorated square-lattice are studied numerically. The square-lattice point and the decorated site denote intersections and roads, respectively. In the present model, a car has a finite deterministic path between the origin and the destination, which is assigned to the car from the beginning. In this new model, we found a new phase between the free-flow phase and the frozen-jam phase that is absent from previous models. The new model is characterized by the persistence of a macroscopic cluster. Furthermore, the behavior in this macroscopic cluster phase is classified into three regions characterized by the shape of the cluster. The boundary of the three regions is phenomenologically estimated. When the trip length is short and the car density is high, both ends of the belt-like cluster connect to each other through the periodic boundary with some probability. This type of cluster is classified topologically as a string on a two-dimensional torus.
A comparison of three programming models for adaptive applications on the Origin2000
Energy Technology Data Exchange (ETDEWEB)
Shan, Hongzhang; Singh, Jaswinder Pal; Oliker, Leonid; Biswas, Rupak
2001-05-30
Adaptive applications have computational workloads and communication patterns which change unpredictably at runtime, requiring dynamic load balancing to achieve scalable performance on parallel machines. Efficient parallel implementations of such adaptive applications is therefore a challenging task. In this paper, we compare the performance of and the programming effort required for two major classes of adaptive applications under three leading parallel programming models on an SGI Origin2000 system, a machine which supports all three models efficiently. Results indicate that the three models deliver comparable performance; however, the implementations differ significantly beyond merely using explicit messages versus implicit loads/stores even though the basic parallel algorithms are similar. Compared with the message-passing (using MPI) and SHMEM programming models, the cache-coherent shared address space (CC-SAS) model provides substantial ease of programming at both the conceptual and program orchestration levels, often accompanied by performance gains. However, CC-SAS currently has portability limitations and may suffer from poor spatial locality of physically distributed shared data on large numbers of processors.
Using an isolated rat kidney model to identify kidney origin proteins in urine.
Directory of Open Access Journals (Sweden)
Lulu Jia
Full Text Available The use of targeted proteomics to identify urinary biomarkers of kidney disease in urine can avoid the interference of serum proteins. It may provide better sample throughput, higher sensitivity, and specificity. Knowing which urinary proteins to target is essential. By analyzing the urine from perfused isolated rat kidneys, 990 kidney origin proteins with human analogs were identified in urine. Of these proteins, 128 were not found in normal human urine and may become biomarkers with zero background. A total of 297 proteins were not found in normal human plasma. These proteins will not be influenced by other normal organs and will be kidney specific. The levels of 33 proteins increased during perfusion with an oxygen-deficient solution compared to those perfused with oxygen. The 75 proteins in the perfusion-driven urine have a significantly increased abundance ranking compared to their ranking in normal human urine. When compared with existing candidate biomarkers, over ninety percent of the kidney origin proteins in urine identified in this study have not been examined as candidate biomarkers of kidney diseases.
Directory of Open Access Journals (Sweden)
Feng Liu
2013-06-01
Full Text Available In this study, we research the problem of network revenue management with customer choice based on the Origin-Destination (O-D demands. By dividing customers into different segments according to O-D pairs, we consider a network capacity control problem where each customer chooses the open product within the segment he belongs to. Starting with a Markov Decision Process (MDP formulation, we approximate the value function with an affine function of the state vector. The affine function approximation results in a new Linear Program (LP which yields tighter bounds than the Choice-based Deterministic Linear Program (CDLP. We give a column generation procedure for solving the LP within a desired optimality tolerance and present numerical results which show the policy perform from our solution approach can outperform that from the CDLP.
Directory of Open Access Journals (Sweden)
Matt Nitzken
2016-03-01
Full Text Available To improve the tagged cardiac magnetic resonance (CMR image analysis, we propose a 3D (2D space + 1D time energy minimization framework, based on learning first- and second-order visual appearance models from voxel intensities. The former model approximates the marginal empirical distribution of intensities with two linear combinations of discrete Gaussians (LCDG. The second-order model considers an image of a sample from a translation–rotation invariant 3D Markov–Gibbs random field (MGRF with multiple pairwise spatiotemporal interactions within and between adjacent temporal frames. Abilities of the framework to accurately recover noise-corrupted strain slopes were experimentally evaluated and validated on 3D geometric phantoms and independently on in vivo data. In multiple noise and motion conditions, the proposed method outperformed comparative image filtering in restoring strain curves and reliably improved HARP strain tracking during the entirety of the cardiac cycle. According to these results, our framework can augment popular spectral domain techniques, such as HARP, by optimizing the spectral domain characteristics and thereby providing more reliable estimates of strain parameters.
Yang, Si-Tong; Wei, Jiu-Chuan; Cheng, Jiu-Long; Shi, Long-Qing; Wen, Zhi-Jie
2016-12-01
Currently, numerical simulations of seismic channel waves for the advance detection of geological structures in coal mine roadways focus mainly on modeling twodimensional wave fields and therefore cannot accurately simulate three-dimensional (3-D) full-wave fields or seismic records in a full-space observation system. In this study, we use the first-order velocity-stress staggered-grid finite difference algorithm to simulate 3-D full-wave fields with P-wave sources in front of coal mine roadways. We determine the three components of velocity V x, V y, and V z for the same node in 3-D staggered-grid finite difference models by calculating the average value of V y, and V z of the nodes around the same node. We ascertain the wave patterns and their propagation characteristics in both symmetrical and asymmetric coal mine roadway models. Our simulation results indicate that the Rayleigh channel wave is stronger than the Love channel wave in front of the roadway face. The reflected Rayleigh waves from the roadway face are concentrated in the coal seam, release less energy to the roof and floor, and propagate for a longer distance. There are surface waves and refraction head waves around the roadway. In the seismic records, the Rayleigh wave energy is stronger than that of the Love channel wave along coal walls of the roadway, and the interference of the head waves and surface waves with the Rayleigh channel wave is weaker than with the Love channel wave. It is thus difficult to identify the Love channel wave in the seismic records. Increasing the depth of the receivers in the coal walls can effectively weaken the interference of surface waves with the Rayleigh channel wave, but cannot weaken the interference of surface waves with the Love channel wave. Our research results also suggest that the Love channel wave, which is often used to detect geological structures in coal mine stopes, is not suitable for detecting geological structures in front of coal mine roadways
Motility at the origin of life: its characterization and a model.
Froese, Tom; Virgo, Nathaniel; Ikegami, Takashi
2014-01-01
Due to recent advances in synthetic biology and artificial life, the origin of life is currently a hot topic of research. We review the literature and argue that the two traditionally competing replicator-first and metabolism-first approaches are merging into one integrated theory of individuation and evolution. We contribute to the maturation of this more inclusive approach by highlighting some problematic assumptions that still lead to an ximpoverished conception of the phenomenon of life. In particular, we argue that the new consensus has so far failed to consider the relevance of intermediate time scales. We propose that an adequate theory of life must account for the fact that all living beings are situated in at least four distinct time scales, which are typically associated with metabolism, motility, development, and evolution. In this view, self-movement, adaptive behavior, and morphological changes could have already been present at the origin of life. In order to illustrate this possibility, we analyze a minimal model of lifelike phenomena, namely, of precarious, individuated, dissipative structures that can be found in simple reaction-diffusion systems. Based on our analysis, we suggest that processes on intermediate time scales could have already been operative in prebiotic systems. They may have facilitated and constrained changes occurring in the faster- and slower-paced time scales of chemical self-individuation and evolution by natural selection, respectively.
Kim, Keehoon; Rodgers, Arthur
2017-08-01
Vertical stratification in the low atmosphere impacts near-ground sound propagation. On clear days, for example, negative gradients of low-atmospheric temperature can lead to upward refraction of acoustic waves and create a zone of silence near the ground, where no acoustic rays can arrive. We investigate impacts of lower tropospheric temperature and wind-velocity gradient on acoustic wave propagation using numerical simulations. Sound refraction in the atmosphere is a frequency-dependent wave phenomenon, and therefore classical ray methods based on infinite-frequency approximation may not be suitable for modeling acoustic wave amplitudes. In this study, a full-waveform acoustic solver was used to predict amplitudes of acoustic waves taking into account meteorological conditions (temperature, pressure and wind). Local radiosonde sounding data were input into acoustic simulations to characterize the background conditions of the local atmosphere. The results of numerical modeling indicate that acoustic overpressure amplitudes were significantly affected by local atmospheric wind speed and direction near the ground. Local wind changes the effective sound speed profile in the atmosphere and influences overpressure amplitude decay governed by upward refraction. We compared 3-D finite-difference modeling results with acoustic overpressure measurements from the Humming Roadrunner explosion experiments conducted in New Mexico in 2012. The modeling results showed good agreement with the observations in peak amplitudes when a background wind was weak and well characterized by local atmospheric data. However, when a strong wind was present at an explosion and its variability was poorly characterized by local radiosonde sounding, the numerical prediction of local acoustic amplitude agreed poorly with the observations. Additional numerical simulations with the inclusion of surface wind data indicate that local acoustic amplitudes could be significantly variable depending on
Bochenkov, Vladimir; Suetin, Nikolay; Shankar, Sadasivan
2014-09-07
A new method, the Extended Temperature-Accelerated Dynamics (XTAD), is introduced for modeling long-timescale evolution of large rare-event systems. The method is based on the Temperature-Accelerated Dynamics approach [M. Sørensen and A. Voter, J. Chem. Phys. 112, 9599 (2000)], but uses full-scale parallel molecular dynamics simulations to probe a potential energy surface of an entire system, combined with the adaptive on-the-fly system decomposition for analyzing the energetics of rare events. The method removes limitations on a feasible system size and enables to handle simultaneous diffusion events, including both large-scale concerted and local transitions. Due to the intrinsically parallel algorithm, XTAD not only allows studies of various diffusion mechanisms in solid state physics, but also opens the avenue for atomistic simulations of a range of technologically relevant processes in material science, such as thin film growth on nano- and microstructured surfaces.
Directory of Open Access Journals (Sweden)
Giulia Morra
2009-03-01
Full Text Available Hsp90 is a molecular chaperone essential for protein folding and activation in normal homeostasis and stress response. ATP binding and hydrolysis facilitate Hsp90 conformational changes required for client activation. Hsp90 plays an important role in disease states, particularly in cancer, where chaperoning of the mutated and overexpressed oncoproteins is important for function. Recent studies have illuminated mechanisms related to the chaperone function. However, an atomic resolution view of Hsp90 conformational dynamics, determined by the presence of different binding partners, is critical to define communication pathways between remote residues in different domains intimately affecting the chaperone cycle. Here, we present a computational analysis of signal propagation and long-range communication pathways in Hsp90. We carried out molecular dynamics simulations of the full-length Hsp90 dimer, combined with essential dynamics, correlation analysis, and a signal propagation model. All-atom MD simulations with timescales of 70 ns have been performed for complexes with the natural substrates ATP and ADP and for the unliganded dimer. We elucidate the mechanisms of signal propagation and determine "hot spots" involved in interdomain communication pathways from the nucleotide-binding site to the C-terminal domain interface. A comprehensive computational analysis of the Hsp90 communication pathways and dynamics at atomic resolution has revealed the role of the nucleotide in effecting conformational changes, elucidating the mechanisms of signal propagation. Functionally important residues and secondary structure elements emerge as effective mediators of communication between the nucleotide-binding site and the C-terminal interface. Furthermore, we show that specific interdomain signal propagation pathways may be activated as a function of the ligand. Our results support a "conformational selection model" of the Hsp90 mechanism, whereby the protein may
Keller, Krista A; Paul-Murphy, Joanne; Weber, E P Scott; Kass, Philip H; Guzman, Sanchez-Migallon David; Park, Shin Ae; Raghunathan, Vijay Krishna; Gustavsen, Kate A; Murphy, Christopher J
2014-12-01
Wounds in reptiles are a common reason for presentation to a veterinarian. At this time there is limited information on effective topical medications to aid in wound closure. The objectives of this study were to translate the splinted, full-thickness dermal wound model, validated in mice, to the bearded dragon (Pogona vitticeps) and to determine the effect of topical becaplermin (BP), a platelet-derived growth factor (0.01%), on the rate of wound closure. Ten bearded dragons were anesthetized and two full-thickness cutaneous wounds were made on the dorsum of each lizard. Encircling splints were applied surrounding each wound and subsequently covered by a semi-occlusive dressing. Five lizards had one wound treated with BP and the adjacent wound treated with a vehicle control. Five additional lizards had one wound treated with saline and the second wound treated with a vehicle control. Wounds were imaged daily, and the wound area was measured using digital image analysis. The change in percentage wound closure over 17 days and the time to 50% wound closure was compared among the four treatment groups. There was no significant difference in wound closure rates between BP-treated and saline-treated wounds or in the time to 50% wound closure between any treatments. Vehicle-treated wounds adjacent to saline-treated wounds closed significantly slower than did BP (P < 0.010), saline (P < 0.001), and vehicle-treated wounds adjacent to BP-treated wounds (P < 0.013). Our preliminary study indicates that the splinted wound model, with modifications, may be used to determine wound closure rates in bearded dragons. When compared with saline, BP did not have a significant effect on wound closure rates, while the vehicle alone delayed wound closure. Histologic analysis of experimentally created wounds throughout the wound healing process is needed to further evaluate the effects of these treatments on reptile dermal wound healing.
De Santis, Roberto; Mollica, Francesco; Zarone, Fernando; Ambrosio, Luigi; Nicolais, Luigi
2007-01-01
A composite model of the mandible, constituted by an inner polymeric core and a glass fibre reinforced outer shell, has been developed and equipped with six ITI titanium implants and a full gold alloy arch bridge prosthesis. The effects of this oral rehabilitation on the biomechanics of the mandible are investigated through a simulation of the lateral component of the pterygoid muscles. These muscles are involved as the mouth is opened and closed, hence their activity is very frequent. An increase of the mandible stiffness due to the prosthesis is observed; moreover, the coupling of the relatively stiff rehabilitation devices with the natural tissue analogue leads to stress-shielding and stress-concentration in the incisal and molar regions, respectively. Although the amplitude of the force generated by pterygoid muscles is quite small, high strains over the incisal region are measured. A stress-shielding effect, of about 20%, is observed at the symphysis as the full arch bridge prosthesis is fixed on the implants. Therefore, the presence of the prosthesis leads to significant modification of the stress field experienced by the mandible, and this may be relevant in relation to the biomechanics of mandibular bone remodelling.
Haggerty, Stephen E.
2014-03-01
Carbonado-diamond is the most controversial of all diamond types and is found only in Brazil, and the Central African Republic (Bangui). Neither an affinity to Earth's mantle, nor an origin in the crust can be unequivocally established. Carbonado-diamond is at least 3.8 Ga old, an age about 0.5 Ga older than the oldest diamonds yet reported in kimberlites and lamproites on Earth. Derived from Neo- to Mid-Proterozoic meta-conglomerates, the primary magmatic host rock has not been identified. Discovered in 1841, the material is polycrystalline, robust and coke-like, and is best described as a strongly bonded micro-diamond ceramic. It is characteristically porous, which precludes an origin at high pressures and high temperatures in Earth's deep interior, yet it is also typically patinated, with a glass-like surface that resembles melting. With exotic inclusions of highly reduced metals, carbides, and nitrides the origin of carbonado-diamond is made even more challenging. But the challenge is important because a new diamondiferous host rock may be involved, and the development of a new physical process for generating diamond is possibly assured. The combination of micro-crystals and random crystal orientation leads to extreme mechanical toughness, and a predicable super-hardness. The physical and chemical properties of carbonado are described with a view to the development of a mimetic strategy to synthesize carbonado and to duplicate its extreme toughness and super-hardness. Textural variations are described with an emphasis on melt-like surface features, not previously discussed in the literature, but having a very clear bearing on the history and genesis of carbonado. Selected physical properties are presented and the proposed origins, diverse in character and imaginatively novel, are critically reviewed. From our present knowledge of the dynamic Earth, all indications are that carbonado is unlikely to be of terrestrial origin. A revised model for the origin of
Warren, Paul H.; Kallemeyn, Gregory W.
1989-01-01
Bulk-compositional data for the EET83309 polymict ureilite were obtained using INAA and radiochemistry procedures and electron probe analysis. It was found that the EET83309 has a bulk composition indistinguishable from ordinary ('monomict') ureilites for all elements except light-middle REEs (which are present in much higher concentrations), suggesting that polymict ureilites are mixtures of ordinary ureilites which were mixed on a very small number of parent bodies. Despite the light-REE enrichments, polymict ureilites are nearly devoid of basaltic (Al-rich) material. It is suggested that the missing basalt may have been blown off the parent body by a partially disruptive collision with a large C-rich projectile. This impact model of ureilite origin reconciles many paradoxical aspects of ureilite composition.
Determination of the sphere origin for MEG source modelling in temporal regions.
Teale, Peter; Benkers, Tara; Rojas, Donald; Reite, Martin
2002-04-07
This paper addresses the choice of spherical volume used in modelling MEG data recorded from temporal (auditory cortex) brain regions. We used MRI data sets to compute best-fitting spheres for the cranial cavity or inner skull table, and for the outer scalp surface. In addition, a 'generic' sphere was computed as the mean of the origin coordinates for the cranial spheres. The effects of these sphere choices were evaluated by estimating equivalent current dipoles as source generators for the M100 component of the auditory evoked field, and comparing the goodness-of-fit and 95% confidence volumes. Results indicate that for this area the cranial cavity is a better choice of surface to fit than the outer scalp. The 'generic' sphere results were also superior to those obtained using individual outer surfaces.
Models of Ceres' Surface as a Function of Origin and Evolution Scenarios
Castillo, J. C.; Frank, E.; Grazier, K.; Raymond, C. A.
2012-12-01
After its spectacular encounter with Vesta, the Dawn spacecraft is now on its way to the largest object in the main belt, Ceres. The last few years have seen a growing interest in the origin and evolution of this object and increased observational constraints on its geophysical properties and surface chemistry. In 2005, McCord and Sotin (2005) introduced the idea that Ceres could have held a deep ocean for some period of time. Rivkin (2006) discovered carbonates at the surface of Ceres, evidence for chemistry in aqueous environments, an idea reinforced by and Milliken and Rivkin's (2009) suggestion that brucite is a major component of Ceres' surface. See also Rivkin et al. (this conference) for the state of the art on Ceres' surface composition inferred from astronomical observations. In parallel, recent developments in Solar system dynamical evolution (Walsh et al. 2011; Grazier et al. 2012) and cosmochemistry models (Dodson-Robinson et al. 2009) and measurements (d'Alexander et al. 2012) indicate that asteroid volatiles may have been supplied from different sources and included second-phase low-eutectic impurities such as ammonia hydrates. Hence, the upcoming rendezvous of Dawn at Ceres offers the prospect of obtaining constraints on the origin of volatiles in the main belt and the habitability potential of large wet asteroids such as Ceres. Ceres' surface chemistry is the product of multiple parameters and processes: (1) the composition of accreted materials, volatile composition, and the possibility for hydrothermal activity in planetesimals prior to accretion in Ceres (i.e., in objects of the size of chondrite parent bodies); (2) evolution of the rock and ocean chemistry as a consequence of one or several episodes of hydrothermal activity (Castillo-Rogez and McCord 2010), (3) the transportation mechanism that may encompass solid-state convection or cryovolcanism and act as a possible filter against certain species in the ocean; (4) exogenic processing (esp. UV
Dirks-Mulder, Anita; Butôt, Roland; van Schaik, Peter; Wijnands, Jan Willem P M; van den Berg, Roel; Krol, Louie; Doebar, Sadhana; van Kooperen, Kelly; de Boer, Hugo; Kramer, Elena M; Smets, Erik F; Vos, Rutger A; Vrijdaghs, Alexander; Gravendeel, Barbara
2017-03-23
Thousands of flowering plant species attract pollinators without offering rewards, but the evolution of this deceit is poorly understood. Rewardless flowers of the orchid Erycina pusilla have an enlarged median sepal and incised median petal ('lip') to attract oil-collecting bees. These bees also forage on similar looking but rewarding Malpighiaceae flowers that have five unequally sized petals and gland-carrying sepals. The lip of E. pusilla has a 'callus' that, together with winged 'stelidia', mimics these glands. Different hypotheses exist about the evolutionary origin of the median sepal, callus and stelidia of orchid flowers. The evolutionary origin of these organs was investigated using a combination of morphological, molecular and phylogenetic techniques to a developmental series of floral buds of E. pusilla. The vascular bundle of the median sepal indicates it is a first whorl organ but its convex epidermal cells reflect convergence of petaloid features. Expression of AGL6 EpMADS4 and APETALA3 EpMADS14 is low in the median sepal, possibly correlating with its petaloid appearance. A vascular bundle indicating second whorl derivation leads to the lip. AGL6 EpMADS5 and APETALA3 EpMADS13 are most highly expressed in lip and callus, consistent with current models for lip identity. Six vascular bundles, indicating a stamen-derived origin, lead to the callus, stelidia and stamen. AGAMOUS is not expressed in the callus, consistent with its sterilization. Out of three copies of AGAMOUS and four copies of SEPALLATA, EpMADS22 and EpMADS6 are most highly expressed in the stamen. Another copy of AGAMOUS, EpMADS20, and the single copy of SEEDSTICK, EpMADS23, are most highly expressed in the stelidia, suggesting EpMADS22 may be required for fertile stamens. The median sepal, callus and stelidia of E. pusilla appear to be derived from a sepal, a stamen that gained petal identity, and stamens, respectively. Duplications, diversifying selection and changes in spatial
Mörschel, Philipp; Schmidt, Martin U
2015-01-01
A crystallographic quantum-mechanical/molecular-mechanical model (c-QM/MM model) with full space-group symmetry has been developed for molecular crystals. The lattice energy was calculated by quantum-mechanical methods for short-range interactions and force-field methods for long-range interactions. The quantum-mechanical calculations covered the interactions within the molecule and the interactions of a reference molecule with each of the surrounding 12-15 molecules. The interactions with all other molecules were treated by force-field methods. In each optimization step the energies in the QM and MM shells were calculated separately as single-point energies; after adding both energy contributions, the crystal structure (including the lattice parameters) was optimized accordingly. The space-group symmetry was maintained throughout. Crystal structures with more than one molecule per asymmetric unit, e.g. structures with Z' = 2, hydrates and solvates, have been optimized as well. Test calculations with different quantum-mechanical methods on nine small organic molecules revealed that the density functional theory methods with dispersion correction using the B97-D functional with 6-31G* basis set in combination with the DREIDING force field reproduced the experimental crystal structures with good accuracy. Subsequently the c-QM/MM method was applied to nine compounds from the CCDC blind tests resulting in good energy rankings and excellent geometric accuracies.
A full 3D model of fluid flow and heat transfer in an E.B. heated liquid metal bath
Matveichev, A.; Jardy, A.; Bellot, J. P.
2016-07-01
In order to study the dissolution of exogeneous inclusions in the liquid metal during processing of titanium alloys, a series of dipping experiments has been performed in an Electron Beam Melting laboratory furnace. Precise determination of the dissolution kinetics requires knowing and mastering the exact thermohydrodynamic behavior of the melt pool, which implies full 3D modeling of the process. To achieve this goal, one needs to describe momentum and heat transfer, phase change, as well as the development of flow turbulence in the liquid. EB power input, thermal radiation, heat loss through the cooling circuit, surface tension effects (i.e. Marangoni-induced flow) must also be addressed in the model. Therefore a new solver dealing with all these phenomena was implemented within OpenFOAM platform. Numerical results were compared with experimental data from actual Ti melting, showing a pretty good agreement. In the second stage, the immersion of a refractory sample rod in the liquid pool was simulated. Results of the simulations showed that the introduction of the sample slightly disturbs the flow field inside the bath. The amount of such disturbance depends on the exact location of the dipping.
Energy Technology Data Exchange (ETDEWEB)
Franz, Johannes [Max Planck Institute for Polymer Research, Mainz (Germany); Graham, Daniel J. [Univ. of Washington, Seattle, WA (United States). NESAC/BIO; Schmüser, Lars [Max Planck Institute for Polymer Research, Mainz (Germany); Baio, Joe E. [Oregon State Univ., Corvallis, OR (United States); Lelle, Marco [Max Planck Institute for Polymer Research, Mainz (Germany); Peneva, Kalina [Max Planck Institute for Polymer Research, Mainz (Germany); Müllen, Klaus [Max Planck Institute for Polymer Research, Mainz (Germany); Castner, David G. [Univ. of Washington, Seattle, WA (United States). NESAC/BIO; Bonn, Mischa [Max Planck Institute for Polymer Research, Mainz (Germany); Weidner, Tobias [Max Planck Institute for Polymer Research, Mainz (Germany)
2015-03-01
Biophysical studies of the interaction of peptides with model membranes provide a simple yet effective approach to understand the transport of peptides and peptide based drug carriers across the cell membrane. Therein, the authors discuss the use of self-assembled monolayers fabricated from the full membrane-spanning thiol (FMST) 3-((14-((4'-((5-methyl-1-phenyl-35-(phytanyl)oxy-6,9,12,15,18,21,24,27,30,33,37-undecaoxa-2,3-dithiahenpentacontan-51-yl)oxy)-[1,1'-biphenyl]-4-yl)oxy)tetradecyl)oxy)-2-(phytanyl)oxy glycerol for ultrahigh vacuum (UHV) based experiments. UHV-based methods such as electron spectroscopy and mass spectrometry can provide important information about how peptides bind and interact with membranes, especially with the hydrophobic core of a lipid bilayer. Moreover, near-edge x-ray absorption fine structure spectra and x-ray photoelectron spectroscopy (XPS) data showed that FMST forms UHV-stable and ordered films on gold. XPS and time of flight secondary ion mass spectrometry depth profiles indicated that a proline-rich amphipathic cell-penetrating peptide, known as sweet arrow peptide is located at the outer perimeter of the model membrane.
Bannon, Erika T.; Bower, Chad E.; Sheth, Rubik; Stephan, Ryan
2010-01-01
In order to control system and component temperatures, many spacecraft thermal control systems use a radiator coupled with a pumped fluid loop to reject waste heat from the vehicle. Since heat loads and radiation environments can vary considerably according to mission phase, the thermal control system must be able to vary the heat rejection. The ability to "turn down" the heat rejected from the thermal control system is critically important when designing the system. Electrochromic technology as a radiator coating is being investigated to vary the amount of heat rejected by a radiator. Coupon level tests were performed to test the feasibility of this technology. Furthermore, thermal math models were developed to better understand the turndown ratios required by full scale radiator architectures to handle the various operation scenarios encountered during a mission profile for the Altair Lunar Lander. This paper summarizes results from coupon level tests as well as the thermal math models developed to investigate how electrochromics can be used to increase turn down ratios for a radiator. Data from the various design concepts of radiators and their architectures are outlined. Recommendations are made on which electrochromic radiator concept should be carried further for future thermal vacuum testing.
Full-length model of the human galectin-4 and insights into dynamics of inter-domain communication
Rustiguel, Joane K.; Soares, Ricardo O. S.; Meisburger, Steve P.; Davis, Katherine M.; Malzbender, Kristina L.; Ando, Nozomi; Dias-Baruffi, Marcelo; Nonato, Maria Cristina
2016-09-01
Galectins are proteins involved in diverse cellular contexts due to their capacity to decipher and respond to the information encoded by β-galactoside sugars. In particular, human galectin-4, normally expressed in the healthy gastrointestinal tract, displays differential expression in cancerous tissues and is considered a potential drug target for liver and lung cancer. Galectin-4 is a tandem-repeat galectin characterized by two carbohydrate recognition domains connected by a linker-peptide. Despite their relevance to cell function and pathogenesis, structural characterization of full-length tandem-repeat galectins has remained elusive. Here, we investigate galectin-4 using X-ray crystallography, small- and wide-angle X-ray scattering, molecular modelling, molecular dynamics simulations, and differential scanning fluorimetry assays and describe for the first time a structural model for human galectin-4. Our results provide insight into the structural role of the linker-peptide and shed light on the dynamic characteristics of the mechanism of carbohydrate recognition among tandem-repeat galectins.
Energy Technology Data Exchange (ETDEWEB)
Xiao, Nan [Department of Bioengineering, Stanford University, Stanford, CA 94305 (United States); Department of Biomedical Engineering, King’s College London, London SE1 7EH (United Kingdom); Humphrey, Jay D. [Department of Biomedical Engineering, Yale University, New Haven, CT 06520 (United States); Figueroa, C. Alberto, E-mail: alberto.figueroa@kcl.ac.uk [Department of Biomedical Engineering, King’s College London, London SE1 7EH (United Kingdom)
2013-07-01
In this article, we present a computational multi-scale model of fully three-dimensional and unsteady hemodynamics within the primary large arteries in the human. Computed tomography image data from two different patients were used to reconstruct a nearly complete network of the major arteries from head to foot. A linearized coupled-momentum method for fluid–structure-interaction was used to describe vessel wall deformability and a multi-domain method for outflow boundary condition specification was used to account for the distal circulation. We demonstrated that physiologically realistic results can be obtained from the model by comparing simulated quantities such as regional blood flow, pressure and flow waveforms, and pulse wave velocities to known values in the literature. We also simulated the impact of age-related arterial stiffening on wave propagation phenomena by progressively increasing the stiffness of the central arteries and found that the predicted effects on pressure amplification and pulse wave velocity are in agreement with findings in the clinical literature. This work demonstrates the feasibility of three-dimensional techniques for simulating hemodynamics in a full-body compliant arterial network.
Calculus domains modelled using an original bool algebra based on polygons
Oanta, E.; Panait, C.; Raicu, A.; Barhalescu, M.; Axinte, T.
2016-08-01
Analytical and numerical computer based models require analytical definitions of the calculus domains. The paper presents a method to model a calculus domain based on a bool algebra which uses solid and hollow polygons. The general calculus relations of the geometrical characteristics that are widely used in mechanical engineering are tested using several shapes of the calculus domain in order to draw conclusions regarding the most effective methods to discretize the domain. The paper also tests the results of several CAD commercial software applications which are able to compute the geometrical characteristics, being drawn interesting conclusions. The tests were also targeting the accuracy of the results vs. the number of nodes on the curved boundary of the cross section. The study required the development of an original software consisting of more than 1700 computer code lines. In comparison with other calculus methods, the discretization using convex polygons is a simpler approach. Moreover, this method doesn't lead to large numbers as the spline approximation did, in that case being required special software packages in order to offer multiple, arbitrary precision. The knowledge resulted from this study may be used to develop complex computer based models in engineering.
Campbell, Ian M; Stewart, Jonathan R; James, Regis A; Lupski, James R; Stankiewicz, Paweł; Olofsson, Peter; Shaw, Chad A
2014-10-02
Most new mutations are observed to arise in fathers, and increasing paternal age positively correlates with the risk of new variants. Interestingly, new mutations in X-linked recessive disease show elevated familial recurrence rates. In male offspring, these mutations must be inherited from mothers. We previously developed a simulation model to consider parental mosaicism as a source of transmitted mutations. In this paper, we extend and formalize the model to provide analytical results and flexible formulas. The results implicate parent of origin and parental mosaicism as central variables in recurrence risk. Consistent with empirical data, our model predicts that more transmitted mutations arise in fathers and that this tendency increases as fathers age. Notably, the lack of expansion later in the male germline determines relatively lower variance in the proportion of mutants, which decreases with paternal age. Subsequently, observation of a transmitted mutation has less impact on the expected risk for future offspring. Conversely, for the female germline, which arrests after clonal expansion in early development, variance in the mutant proportion is higher, and observation of a transmitted mutation dramatically increases the expected risk of recurrence in another pregnancy. Parental somatic mosaicism considerably elevates risk for both parents. These findings have important implications for genetic counseling and for understanding patterns of recurrence in transmission genetics. We provide a convenient online tool and source code implementing our analytical results. These tools permit varying the underlying parameters that influence recurrence risk and could be useful for analyzing risk in diverse family structures.
García, E.; Oliver, A.; Diaz, O.; Diez, Y.; Gubern-Mérida, A.; Martí, R.; Martí, J.
2017-03-01
Patient-specific finite element (FE) models of the breast have received increasing attention due to the potential capability of fusing images from different modalities. During the Magnetic Resonance Imaging (MRI) to X-ray mammography registration procedure, the FE model is compressed mimicking the mammographic acquisition. Subsequently, suspicious lesions in the MRI volume can be projected into the 2D mammographic space. However, most registration algorithms do not provide the reverse information, avoiding to obtain the 3D geometrical information from the lesions localized in the mammograms. In this work we introduce a fast method to localize the 3D position of the lesion within the MRI, using both cranio-caudal (CC) and medio-lateral oblique (MLO) mammographic projections, indexing the tetrahedral elements of the biomechanical model by means of an uniform grid. For each marked lesion in the Full-Field Digital Mammogram (FFDM), the X-ray path from source to the marker is calculated. Barycentric coordinates are computed in the tetrahedrons traversed by the ray. The list of elements and coordinates allows to localize two curves within the MRI and the closest point between both curves is taken as the 3D position of the lesion. The registration errors obtained in the mammographic space are 9.89 +/- 3.72 mm in CC- and 8.04 +/- 4.68 mm in MLO-projection and the error in the 3D MRI space is equal to 10.29 +/- 3.99 mm. Regarding the uniform grid, it is computed spending between 0.1 and 0.7 seconds. The average time spent to compute the 3D location of a lesion is about 8 ms.
Fabien-Ouellet, Gabriel; Gloaguen, Erwan; Giroux, Bernard
2017-03-01
Full Waveform Inversion (FWI) aims at recovering the elastic parameters of the Earth by matching recordings of the ground motion with the direct solution of the wave equation. Modeling the wave propagation for realistic scenarios is computationally intensive, which limits the applicability of FWI. The current hardware evolution brings increasing parallel computing power that can speed up the computations in FWI. However, to take advantage of the diversity of parallel architectures presently available, new programming approaches are required. In this work, we explore the use of OpenCL to develop a portable code that can take advantage of the many parallel processor architectures now available. We present a program called SeisCL for 2D and 3D viscoelastic FWI in the time domain. The code computes the forward and adjoint wavefields using finite-difference and outputs the gradient of the misfit function given by the adjoint state method. To demonstrate the code portability on different architectures, the performance of SeisCL is tested on three different devices: Intel CPUs, NVidia GPUs and Intel Xeon PHI. Results show that the use of GPUs with OpenCL can speed up the computations by nearly two orders of magnitudes over a single threaded application on the CPU. Although OpenCL allows code portability, we show that some device-specific optimization is still required to get the best performance out of a specific architecture. Using OpenCL in conjunction with MPI allows the domain decomposition of large models on several devices located on different nodes of a cluster. For large enough models, the speedup of the domain decomposition varies quasi-linearly with the number of devices. Finally, we investigate two different approaches to compute the gradient by the adjoint state method and show the significant advantages of using OpenCL for FWI.
Morgan, H. L., Jr.
1981-01-01
An investigation was conducted in the Langley 4 by 7 Meter Tunnel to determine the static longitudinal and lateral directional aerodynamic characteristics of an advanced aspect ratio 10 supercritical wing transport model equipped with a full span leading edge slat as well as part span and full span trailing edge flaps. This wide body transport model was also equipped with spoiler and aileron roll control surfaces, flow through nacelles, landing gear, and movable horizontal tails. Six basic wing configurations were tested: (1) cruise (slats and flaps nested), (2) climb (slats deflected and flaps nested), (3) part span flap, (4) full span flap, (5) full span flap with low speed ailerons, and (6) full span flap with high speed ailerons. Each of the four flapped wing configurations was tested with leading edge slat and trailing edge flaps deflected to settings representative of both take off and landing conditions. Tests were conducted at free stream conditions corresponding to Reynolds number of 0.97 to 1.63 x 10 to the 6th power and corresponding Mach numbers of 0.12 to 0.20, through an angle of attack range of 4 to 24, and a sideslip angle range of -10 deg to 5 deg. The part and full span wing configurations were also tested in ground proximity.
Simeon, Saw; Anuwongcharoen, Nuttapat; Shoombuatong, Watshara; Malik, Aijaz Ahmad; Prachayasittikul, Virapong; Wikberg, Jarl E S; Nantasenamat, Chanin
2016-01-01
Alzheimer's disease (AD) is a chronic neurodegenerative disease which leads to the gradual loss of neuronal cells. Several hypotheses for AD exists (e.g., cholinergic, amyloid, tau hypotheses, etc.). As per the cholinergic hypothesis, the deficiency of choline is responsible for AD; therefore, the inhibition of AChE is a lucrative therapeutic strategy for the treatment of AD. Acetylcholinesterase (AChE) is an enzyme that catalyzes the breakdown of the neurotransmitter acetylcholine that is essential for cognition and memory. A large non-redundant data set of 2,570 compounds with reported IC50 values against AChE was obtained from ChEMBL and employed in quantitative structure-activity relationship (QSAR) study so as to gain insights on their origin of bioactivity. AChE inhibitors were described by a set of 12 fingerprint descriptors and predictive models were constructed from 100 different data splits using random forest. Generated models afforded R (2), [Formula: see text] and [Formula: see text] values in ranges of 0.66-0.93, 0.55-0.79 and 0.56-0.81 for the training set, 10-fold cross-validated set and external set, respectively. The best model built using the substructure count was selected according to the OECD guidelines and it afforded R (2), [Formula: see text] and [Formula: see text] values of 0.92 ± 0.01, 0.78 ± 0.06 and 0.78 ± 0.05, respectively. Furthermore, Y-scrambling was applied to evaluate the possibility of chance correlation of the predictive model. Subsequently, a thorough analysis of the substructure fingerprint count was conducted to provide informative insights on the inhibitory activity of AChE inhibitors. Moreover, Kennard-Stone sampling of the actives were applied to select 30 diverse compounds for further molecular docking studies in order to gain structural insights on the origin of AChE inhibition. Site-moiety mapping of compounds from the diversity set revealed three binding anchors encompassing both hydrogen bonding and van der Waals
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
A full second-order moment (FSM) model and an algebraic stress (ASM) two-phase turbulence modelare proposed and applied to predict turbulent bubble-liquid flows in a 2D rectangular bubble column. Predictiongives the bubble and liquid velocities, bubble volume fraction, bubble and liquid Reynolds stresses and bubble-liquidvelocity correlation. For predicted two-phase velocities and bubble volume fraction there is only slight differencebetween these two models, and the simulation results using both two models are in good agreement with the particleimage velocimetry (PIV) measurements. Although the predicted two-phase Reynolds stresses using the FSM are insomewhat better agreement with the PIV measurements than those predicted using the ASM, the Reynolds stressespredicted using both two models are in general agreement with the experiments. Therefore, it is suggested to usethe ASM two-phase turbulence model in engineering application for saving the computation time.
The healing effect of four different silver complexes on full-thickness skin burns in a rat model.
Gouma, Efthalia; Batistatou, Anna; Verginadis, Ioannis I; Simos, Yannis V; Kyros, Loukas; Hadjikakou, Sotiris K; Karkabounas, Spyridon Ch; Evangelou, Angelos M; Ragos, Vasilios N; Peschos, Dimitrios
2015-01-01
This study was carried-out to investigate the effect of four different silver substances (S1, S2, S3, and S4) on burn wound healing in a rat model. One hundred and eighty Wistar rats were used. Animals were randomized into six groups to receive no treatment (CG, control group), and local application of the solvent of silver substances (SG, solvent group), as well as of the four silver substances (EG1-EG4 groups for substances S1-S4, respectively). On days 0, 3, 6, 12, 21, and 31 following burn wound infliction, the size and healing progress of each wound were recorded and evaluated by means of clinical evaluation, planimetry and histological examination. According to our findings lower infection rates, as well as significantly accelerated wound healing and faster re-epithelialization were recorded in EG1, EG2, and EG4 compared to the other groups. The use of S1, S2, and S4 substances proved to be an effective treatment of burn wounds that ensured better outcomes compared to the control and solvent groups, as well as with the use of S3 substance. Nevertheless, they failed to produce short-term healing of the full-thickness burn. Further research is required to examine the possibility of speeding the treatment of full-thickness burns by these complexes in order to reduce healing time to acceptable limits and prevent the need for surgery. Copyright © 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.
Jang, Jinwoo; Smyth, Andrew W.
2017-01-01
The objective of structural model updating is to reduce inherent modeling errors in Finite Element (FE) models due to simplifications, idealized connections, and uncertainties of material properties. Updated FE models, which have less discrepancies with real structures, give more precise predictions of dynamic behaviors for future analyses. However, model updating becomes more difficult when applied to civil structures with a large number of structural components and complicated connections. In this paper, a full-scale FE model of a major long-span bridge has been updated for improved consistency with real measured data. Two methods are applied to improve the model updating process. The first method focuses on improving the agreement of the updated mode shapes with the measured data. A nonlinear inequality constraint equation is used to an optimization procedure, providing the capability to regulate updated mode shapes to remain within reasonable agreements with those observed. An interior point algorithm deals with nonlinearity in the objective function and constraints. The second method finds very efficient updating parameters in a more systematic way. The selection of updating parameters in FE models is essential to have a successful updating result because the parameters are directly related to the modal properties of dynamic systems. An in-depth sensitivity analysis is carried out in an effort to precisely understand the effects of physical parameters in the FE model on natural frequencies. Based on the sensitivity analysis, cluster analysis is conducted to find a very efficient set of updating parameters.
Simple mechanisms of early life - simulation model on the origin of semi-cells.
Klein, Adrian; Bock, Martin; Alt, Wolfgang
2017-01-01
The development of first cellular structures played an important role in the early evolution of life. Early evolution of life probably took place on a molecular level in a reactive environment. The iron-sulfur theory postulates the formation of cell-like structures on catalytic surfaces. Experiments show that H2S together with FeS and other metallic centers drive auto-catalytic surface reactions, in which organic molecules such as pyruvic and amino acids occur. It is questionable which mechanisms are needed to form cell-like structures under these conditions. To address this question, we implemented a model system featuring the fundamentals of molecular dynamics: heat, attraction, repulsion and formation of covalent bonds. Our basic model exhibits a series of essential processes: self-organization of lipid micelles and bilayers, formation of fluid filled cavities, flux of molecules along membranes, transport of energized groups towards sinks and whole colonies of cell-like structures on a larger scale. The results demonstrate that only a few features are sufficient for discovering hitherto non described phenomena of self-assembly and dynamics of cell-like structures as candidates for early evolving proto-cells. Significance statement The quest for a possible origin of life continues to be one of the most fascinating problems in biology. In one theoretical scenario, early life originated from a solution of reactive chemicals in the ancient deep sea, similar to conditions as to be found in thermal vents. Experiments have shown that a variety of organic molecules, the building blocks of life, form under these conditions. Based on such experiments, the iron-sulfur theory postulates the growth of cell-like structures at certain catalytic surfaces. For an explanation and proof of such a process we have developed a computer model simulating molecular assembly of lipid bilayers and formation of semi-cell cavities. The results demonstrate the possibility of cell-like self
Backtrack modeling to locate the origin of tar balls depositing along the west coast of India.
Suneel, V; Ciappa, A; Vethamony, P
2016-11-01
Tar ball (TB) deposition along the West Coast of India (WCI) is a common phenomenon during the southwest monsoon season, particularly along the coast of Goa and Gujarat, and it is a major concern to the stake holders. Our earlier studies showed that the source oil for the TBs deposited on the Goa coast in August 2010 is the tanker wash, and the source for subsequent TBs deposited on the Gujarat coast during July 2012 and June 2013 and Goa coast in May 2013 is from Bombay High (BH) oil fields. In the present study, the TBs that were deposited during May 2013 and May 2014 on the Goa coast were backtracked through a trajectory model, primarily to simulate their pathways and identify the reason for the occurrence of TBs only in May, and eventually to identify the origin and the source. The backtracking results re-confirmed that the TBs deposited in 2010 were originated from the tanker routes and that of both 2013 and 2014 TBs from the BH oil fields. The climatology of wind and surface circulation showed that the TBs deposited on the Goa coast during May/June only are from the oil fields and those during August from the tanker route. The results of backtracking simulations showed that the residence time of the oil residues/TBs is approximately 22days for August 2010 TBs, ≈30days for May 2013 TBs and 65days for May 2014 TBs. The residence time (in water) of TBs that deposit (on the coast) in the month of May could be as much as 7months, and could be around one month if deposit in August, primarily because of winds and hydrodynamic conditions of the Arabian Sea.
Modeling the Origin and Possible Control of the Wealth Inequality Surge.
Berman, Yonatan; Shapira, Yoash; Ben-Jacob, Eshel
2015-01-01
The rapid increase of wealth inequality in the past few decades is a most disturbing social and economic issue of our time. In order to control, and even reverse that surge, its origin and underlying mechanisms should be revealed. One of the challenges in studying these mechanisms is to incorporate realistic individual dynamics in the population level in a self-consistent manner. Our theoretical approach meets the challenge by using interacting multi-agent master-equations to model the dynamics of wealth inequality. The model is solved using stochastic multi-agent iterated maps. Taking into account growth rate, return on capital, private savings and economic mobility, we were able to capture the historical dynamics of wealth inequality in the United States during the course of the 20th century. We show that the fraction of capital income in the national income and the fraction of private savings are the critical factors that govern the wealth inequality dynamics. In addition, we found that economic mobility plays a crucial role in wealth accumulation. Notably, we found that the major decrease in private savings since the 1980s could be associated primarily with the recent surge in wealth inequality and if nothing changes in this respect we predict further increase in wealth inequality in the future. However, the 2007-08 financial crisis brought an opportunity to restrain the wealth inequality surge by increasing private savings. If this trend continues, it may lead to prevention, and even reversing, of the ongoing inequality surge.
Energy Technology Data Exchange (ETDEWEB)
Hou, Dan; Ma, Yong-Tao; Zhang, Xiao-Long; Li, Hui, E-mail: Prof-huili@jlu.edu.cn [Institute of Theoretical Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023 (China)
2016-01-07
The origin and strength of intra- and inter-molecular vibrational coupling is difficult to probe by direct experimental observations. However, explicitly including or not including some specific intramolecular vibrational modes to study intermolecular interaction provides a precise theoretical way to examine the effects of anharmonic coupling between modes. In this work, a full-dimension intra- and inter-molecular ab initio potential energy surface (PES) for H{sub 2}O–Ar, which explicitly incorporates interdependence on the intramolecular (Q{sub 1}, Q{sub 2}, Q{sub 3}) normal-mode coordinates of the H{sub 2}O monomer, has been calculated. In addition, four analytic vibrational-quantum-state-specific PESs are obtained by least-squares fitting vibrationally averaged interaction energies for the (v{sub 1}, v{sub 2}, v{sub 3}) = (0, 0, 0), (0, 0, 1), (1, 0, 0), (0, 1, 0) states of H{sub 2}O to the three-dimensional Morse/long-range potential function. Each vibrationally averaged PES fitted to 442 points has root-mean-square (rms) deviation smaller than 0.15 cm{sup −1}, and required only 58 parameters. With the 3D PESs of H{sub 2}O–Ar dimer system, we employed the combined radial discrete variable representation/angular finite basis representation method and Lanczos algorithm to calculate rovibrational energy levels. This showed that the resulting vibrationally averaged PESs provide good representations of the experimental infrared data, with rms discrepancies smaller than 0.02 cm{sup −1} for all three rotational branches of the asymmetric stretch fundamental transitions. The infrared band origin shifts associated with three fundamental bands of H{sub 2}O in H{sub 2}O–Ar complex are predicted for the first time and are found to be in good agreement with the (extrapolated) experimental values. Upon introduction of additional intramolecular degrees of freedom into the intermolecular potential energy surface, there is clear
Gasbarri, P.; Monti, R.; De Angelis, C.; Sabatini, M.
2014-01-01
One of the most important problems for performing a good design of the spacecraft attitude control law is connected to its robustness when some uncertainty parameters are present on the inertial and/or on the elastic characteristics of a satellite. These uncertainties are generally intrinsic on the modeling of complex structures and in the case of large flexible structures they can be also attributed to secondary effects associated to the elasticity. One of the most interesting issues in modeling large flexible space structures is associated to the evaluation of the inertia tensor which in general depends not only on the geometric ‘fixed' characteristic of the satellite but also on its elastic displacements which of course in turn modify the ‘shape' of the satellite. Usually these terms can be considered of a second order of magnitude if compared with the ones associated to the rigid part of a structure. However the increasing demand on the dimension of satellites due to the presence for instance of very large solar arrays (necessary to generate power) and/or large antennas has the necessity to investigate their effects on their global dynamic behavior in more details as a consequence. In the present paper a methodology based on classical Lagrangian approach coupled with a standard Finite Element tool has been used to derive the full dynamic equations of an orbiting flexible satellite under the actions of gravity, gravity gradient forces and attitude control. A particular attention has been paid to the study of the effects of flexibility on the inertial terms of the spacecraft which, as well known, influence its attitude dynamic behavior. Furthermore the effects of the attitude control authority and its robustness to the uncertainties on inertial and elastic parameters has been investigated and discussed.
Directory of Open Access Journals (Sweden)
K. T. Lawrence
2013-10-01
Full Text Available Recently, the veracity of the published chronology for the Pliocene section of North Atlantic Ocean Drilling Program Site 982 was called into question. Here, we examine the robustness of the original age model as well as the proposed age model revision. The proposed revision is predicated on an apparent misidentification of the depth to the Gauss–Matuyama (G/M polarity chronozone reversal boundary (2.581 Ma based on preliminary shipboard paleomagnetic data, and offers a new chronology that includes a hiatus between ~3.2 and 3 Ma. However, an even more accurate shore-based, u-channel-derived polarity chronozone stratigraphy for the past ~2.7 Ma supports the shipboard composite stratigraphy and demonstrates that the original estimate of the depth of the G/M reversal in the Site 982 record is correct. Thus, the main justification forwarded to support the revised chronology no longer exists. We demonstrate that the proposed revision results in a pronounced anomaly in sedimentation rates proximal to the proposed hiatus, erroneous assignment of marine-isotope stages in the Site 982 Pliocene benthic stable oxygen isotope stratigraphy, and a markedly worse correlation of proxy records between this site and other regional paleoclimate data. We conclude that the original chronology for Site 982 is a far more accurate age model than that which arises from the published revision. We strongly recommend the use of the original chronology for all future work at Site 982.
Directory of Open Access Journals (Sweden)
K. T. Lawrence
2013-04-01
Full Text Available Recently, the veracity of the published chronology for the Pliocene section of North Atlantic Ocean Drilling Program Site 982 was called into question. Here, we examine the robustness of the original age model as well as the proposed age model revision. The proposed revision is predicated on an apparent mis-identification of the depth to the Gauss-Matuyama (G/M polarity chronozone reversal boundary (2.581 Ma based on preliminary shipboard paleomagnetic data and offers a new chronology which includes a hiatus between ~ 3.2 and 3 Ma. However, an even more accurate shore-based, u-channel-derived polarity chronozone stratigraphy for the past ~ 2.7 Ma supports the shipboard composite stratigraphy and demonstrates that the original estimate of the depth of the G/M reversal in the Site 982 record is correct. Thus, the main justification forwarded to support the revised chronology is not valid. We demonstrate that the proposed revision results in a pronounced anomaly in sedimentation rates proximal to the proposed hiatus, erroneous assignment of marine-isotope stages in the Site 982 Pliocene benthic stable oxygen isotope stratigraphy, and a markedly worse correlation of proxy records between this site and other regional paleoclimate data. We conclude that the original chronology for Site 982 is a far more accurate age-model than that which arises from the published revision. We strongly recommend the use of the original chronology for all future work at Site 982.
Fowler, Marcie; Clifford, John L; Garza, Thomas H; Slater, Terry M; Arizpe, Helen M; Novak, Joseph; Petz, Lawrence N; Loyd, Dayna R
2014-06-01
Opioid-related side effects are problematic for burn patients. Dual mechanism therapeutics targeting opioid and non-opioid mechanisms may have reduced side effects with similar analgesic efficacy. Tramadol combines mu opioid receptor agonism with norepinephrine reuptake inhibition and has been effective in treating some types of pain. The effectiveness of tramadol in treating pain associated with burns is unclear. We hypothesized that tramadol is effective in reducing thermal injury-evoked pain behaviors in a rat model. Rats were anesthetized and a 100°C metal probe was placed on the hindpaw for 30 s to induce a full thickness thermal injury. A subset of rats was perfusion fixed and hindpaw tissue and spinal cord collected for anatomical analysis. Rats received morphine (5 mg/kg; i.p.), tramadol (10-30 mg/kg; i.p.) or vehicle and latency to paw withdrawal from a noxious thermal or non-noxious mechanical stimulus was recorded every 10 min over 70 min and again at 2 h. We report that pain behaviors developed within 48 h and peaked at 1 week; paralleled by enhanced expression of pronociceptive neuropeptides in the spinal cord. Morphine and tramadol significantly attenuated hyperalgesia and allodynia, while not significantly altering motor coordination/sedation. These data indicate dual mechanism therapeutics may be effective for treating pain associated with burns.
Rona-Voros, Krisztina; Eschbach, Judith; Vernay, Aurélia; Wiesner, Diana; Schwalenstocker, Birgit; Geniquet, Pauline; Mousson De Camaret, Bénédicte; Echaniz-Laguna, Andoni; Loeffler, Jean-Philippe; Ludolph, Albert C; Weydt, Patrick; Dupuis, Luc
2013-12-20
Increased mitochondrial mass, commonly termed mitochondrial proliferation, is frequently observed in many human diseases directly or indirectly involving mitochondrial dysfunction. Mitochondrial proliferation is thought to counterbalance a compromised energy metabolism, yet it might also be detrimental through alterations of mitochondrial regulatory functions such as apoptosis, calcium metabolism or oxidative stress. Here, we show that prominent mitochondrial proliferation occurs in Cramping mice, a model of hereditary neuropathy caused by a mutation in the dynein heavy chain gene Dync1h1. The mitochondrial proliferation correlates with post-prandial induction of full-length (FL) and N-terminal truncated (NT) isoforms of the transcriptional co-activator PGC-1α. The selective knock-out of FL-PGC-1α isoform, preserving expression and function of NT-PGC-1α, led to a complete reversal of mitochondrial proliferation. Moreover, FL-PGC-1α ablation potently exacerbated the mitochondrial dysfunction and led to severe weight loss. Finally, FL-PGC-1α ablation triggered pronounced locomotor dysfunction, tremors and inability to rear in Cramping mice. In summary, endogenous FL-PGC-1α activates mitochondrial proliferation and salvages neurological and metabolic health upon disease. NT-PGC-1α cannot fulfil this protective action. Activation of this endogenous salvage pathway might thus be a valuable therapeutic target for diseases involving mitochondrial dysfunction.
Wang, Y.
2015-12-01
Several recent studies based on best track data for tropical cyclones (TCs) over the North Atlantic revealed a strong dependence of the TC intensification rate (IR) on TC intensity. The TC IR shows a maximum (i.e., most rapid intensification) when the TC intensity reaches about 35 - 40 m s-1. Physically, this intensity-dependence has been explained in terms of the inner-core inertial stability and the decreased potential for a TC to intensify as it approaches its maximum potential intensity (MPI). Here, we propose a new simplified dynamical system based on TC energetics. For this purpose, the TC system is considered as a Carnot heat engine as in earlier theoretical studies, and formulated on the grounds of major energy production and dissipation processes. This offers a way to explain the IR behavior of TCs in terms of its sensitivity to the physical processes involved, and to derive a physically-based relationship between TC intensification and intensity. This relationship is consistent with observations, and in quantitative agreement with that gained from empirical relations in an alternative dynamical system proposed by DeMaria(2009), which has been formulated analogously to the logistic growth equation (LGE). Results from idealized full-physics model simulations confirm the validity of several key assumptions implicitly involved in the simplified dynamical system and the intensity-dependence of the TC IR as well.
Institute of Scientific and Technical Information of China (English)
Zheng Li; Rong Qi; Bo Wang; Zhe Zou; Guohong Wei; Min Yang
2013-01-01
A full-scale oxidation ditch process for treating sewage was simulated with the ASM2d model and optimized for minimal cost with acceptable performance in terms of ammonium and phosphorus removal.A unified index was introduced by integrating operational costs (aeration energy and sludge production) with effluent violations for performance evaluation.Scenario analysis showed that,in comparison with the baseline (all of the 9 aerators activated),the strategy of activating 5 aerators could save aeration energy significantly with an ammonium violation below 10％.Sludge discharge scenario analysis showed that a sludge discharge flow of 250-300 m3/day (solid retention time (SRT),13-15 days) was appropriate for the enhancement of phosphorus removal without excessive sludge production.The proposed optimal control strategy was:activating 5 rotating disks operated with a mode of "111100100" ("1"represents activation and "0" represents inactivation) for aeration and sludge discharge flow of 200 m3/day (SRT,19 days).Compared with the baseline,this strategy could achieve ammonium violation below 10％ and TP violation below 30％ with substantial reduction of aeration energy cost (46％) and minimal increment of sludge production (＜ 2％).This study provides a useful approach for the optimization of process operation and control.
Loeffelbein, Denys J; Baumann, Claudia; Stoeckelhuber, Mechthild; Hasler, Rafael; Mücke, Thomas; Steinsträßer, Lars; Drecoll, Enken; Wolff, Klaus-Dietrich; Kesting, Marco R
2012-07-01
We evaluated the use of human amniotic membrane (HAM) as a graft material for the treatment of iatrogenic full-thickness (FT) skin wounds in a porcine model with a view to reducing donor site morbidity in free flap transfer. Forty experimental FT-wounds were covered with an autologous split-thickness skin graft (STSG) alone or in combination with a mono- or multilayer HAM or Integra(®). Untreated wounds served as controls. Clinical evaluation and biopsy-sampling for histological and immunohistochemical staining with von-Willebrand-factor (vWF) antibody, laminin antibody, Ki-67 antibody, and smooth muscle actin (αSMA) antibody were performed on days 5, 7, 10, 20, 40, and 60 after surgical intervention. Considerable disparities in the estimated criteria were observed between the various treatment groups of the FT-wounds. The use of HAM was found to have an accelerating impact on re-epithelialization. The multilayered amnion membrane showed better results than the Integra(®) and monolayer technique in terms of contraction rate, inflammation, and scarring and seemed useful as a dermal substitute in FT-wounds giving comparable results to STSG coverage alone. This study demonstrates the successful application of HAM as part of a skin substitute in FT-wounds in minipigs. The results offer promise as a simple and effective technique for the application of multilayer HAM in iatrogenic human skin defects and the acceleration of wound healing. Copyright © 2012 Wiley Periodicals, Inc.
A cold plasma jet accelerates wound healing in a murine model of full-thickness skin wounds.
Schmidt, Anke; Bekeschus, Sander; Wende, Kristian; Vollmar, Brigitte; von Woedtke, Thomas
2017-02-01
Cold plasma has been successfully applied in several fields of medicine that require, for example, pathogen inactivation, implant functionalization or alteration of cellular activity. Previous studies have provided evidence that plasma supports the healing of wounds owing to its beneficial mixtures of reactive species and modulation of inflammation in cells and tissues. To investigate the wound healing activity of an atmospheric pressure plasma jet in vivo, we examined the cold plasma's efficacy on dermal regeneration in a murine model of dermal full-thickness ear wound. Over 14 days, female mice received daily plasma treatment. Quantitative analysis by transmitted light microscopy demonstrated a significantly accelerated wound re-epithelialization at days 3-9 in comparison with untreated controls. In vitro, cold plasma altered keratinocyte and fibroblast migration, while both cell types showed significant stimulation resulting in accelerated closure of gaps in scratch assays. This plasma effect correlated with the downregulation of the gap junctional protein connexin 43 which is thought to be important in the regulation of wound healing. In addition, plasma induced profound changes in adherence junctions and cytoskeletal dynamics as shown by downregulation of E-cadherin and several integrins as well as actin reorganization. Our results theorize cold plasma to be a beneficial treatment option supplementing existing wound therapies.
Machado, Vinicius Cunha; Lafuente, Javier; Baeza, Juan Antonio
2014-07-01
The present work developed a model for the description of a full-scale wastewater treatment plant (WWTP) (Manresa, Catalonia, Spain) for further plant upgrades based on the systematic parameter calibration of the activated sludge model 2d (ASM2d) using a methodology based on the Fisher information matrix. The influent was characterized for the application of the ASM2d and the confidence interval of the calibrated parameters was also assessed. No expert knowledge was necessary for model calibration and a huge available plant database was converted into more useful information. The effect of the influent and operating variables on the model fit was also studied using these variables as calibrating parameters and keeping the ASM2d kinetic and stoichiometric parameters, which traditionally are the calibration parameters, at their default values. Such an "inversion" of the traditional way of model fitting allowed evaluating the sensitivity of the main model outputs regarding the influent and the operating variables changes. This new approach is able to evaluate the capacity of the operational variables used by the WWTP feedback control loops to overcome external disturbances in the influent and kinetic/stoichiometric model parameters uncertainties. In addition, the study of the influence of operating variables on the model outputs provides useful information to select input and output variables in decentralized control structures.
Fahnestock, Eugene G.; Yu, Yang; Hamilton, Douglas P.; Schwartz, Stephen; Stickle, Angela; Miller, Paul L.; Cheng, Andy F.; Michel, Patrick; AIDA Impact Simulation Working Group
2016-10-01
The proposed Asteroid Impact Deflection and Assessment (AIDA) mission includes NASA's Double Asteroid Redirection Test (DART), whose impact with the secondary of near-Earth binary asteroid 65803 Didymos is expected to liberate large amounts of ejecta. We present efforts within the AIDA Impact Simulation Working Group to comprehensively simulate the behavior of this impact ejecta as it moves through and exits the system. Group members at JPL, OCA, and UMD have been working largely independently, developing their own strategies and methodologies. Ejecta initial conditions may be imported from output of hydrocode impact simulations or generated from crater scaling laws derived from point-source explosion models. We started with the latter approach, using reasonable assumptions for the secondary's density, porosity, surface cohesive strength, and vanishingly small net gravitational/rotational surface acceleration. We adopted DART's planned size, mass, closing velocity, and impact geometry for the cratering event. Using independent N-Body codes, we performed Monte Carlo integration of ejecta particles sampled over reasonable particle size ranges, and over launch locations within the crater footprint. In some cases we scaled the number of integrated particles in various size bins to the estimated number of particles consistent with a realistic size-frequency distribution. Dynamical models used for the particle integration varied, but all included full gravity potential of both primary and secondary, the solar tide, and solar radiation pressure (accounting for shadowing). We present results for the proportions of ejecta reaching ultimate fates of escape, return impact on the secondary, and transfer impact onto the primary. We also present the time history of reaching those outcomes, i.e., ejecta clearing timescales, and the size-frequency distribution of remaining ejecta at given post-impact durations. We find large numbers of particles remain in the system for several
Fetal Origins of Life Stage Disease: A Zebrafish Model for the ...
In the U.S., childhood obesity has more than doubled in children and quadrupled in adolescents in the past 30 years, affects 35% of adults, and costs the U.S. healthcare industry >$200 billion annually. The chemical environment in the womb may cause susceptibility to different life-stage and life-long metabolic diseases including obesity. The challenge is to understand if exposures during developmentally sensitive windows impact life-stage disease, such as obesity, by increasing adipose tissue mass. In vitro models lack the integrated systems approach needed to assess adipose development, while mammalian models are impractical in a screen of thousands of chemicals. Therefore, an obesogen screening method was developed to interrogate bioactivity using a full systems approach, in a vertebrate zebrafish model with complete metabolic activity, at a time when the full signaling repertoire is expressed and active, to optimally examine how chemical dose and duration impact life-stage adipose mass. A time-line for adipose depot formation was mapped in zebrafish 6−14 days post fertilization (dpf) using the lipophilic dye, Nile Red, in combination with fluorescent microscopy. Those time points were then used to investigate the impact of embryonic tributyltin chloride (TBT, a known obesogen) exposure (10nM daily renewal, 0−5dpf) on adipose mass. Fluorescent microscopy revealed adipose depots that were larger and appeared 2 days earlier in TBT treated compared to contro
Føre, Martin; Alver, Morten; Alfredsen, Jo Arve; Marafioti, Giancarlo; Senneset, Gunnar; Birkevold, Jens; Willumsen, Finn Victor; Lange, Guttorm; Espmark, Åsa; Terjesen, Bendik Fyhn
2016-11-01
We have developed a mathematical model which estimates the growth performance of Atlantic salmon in aquaculture production units. The model consists of sub-models estimating the behaviour and energetics of the fish, the distribution of feed pellets, and the abiotic conditions in the water column. A field experiment where three full-scale cages stocked with 120,000 salmon each (initial mean weight 72.1 ± SD 2.8 g) were monitored over six months was used to validate the model. The model was set up to simulate fish growth for all the three cages using the feeding regimes and observed environmental data as input, and simulation results were compared with the experimental data. Experimental fish achieved end weights of 878, 849 and 739 g in the three cages respectively. However, the fish contracted Pancreas Disease (PD) midway through the experiment, a factor which is expected to impair growth and increase mortality rate. The model was found able to predict growth rates for the initial period when the fish appeared to be healthy. Since the effects of PD on fish performance are not modelled, growth rates were overestimated during the most severe disease period. This work illustrates how models can be powerful tools for predicting the performance of salmon in commercial production, and also imply their potential for predicting differences between commercial scale and smaller experimental scales. Furthermore, such models could be tools for early detection of disease outbreaks, as seen in the deviations between model and observations caused by the PD outbreak. A model could potentially also give indications on how the growth performance of the fish will suffer during such outbreaks.
Gorbatikh, Larissa; Lomov, Stepan V.; Verpoest, Ignaas
2010-05-01
Motivated to reveal original mechanisms of failure resistance, we developed a material model that encompasses most reoccurring microstructural features of natural composites. The interesting result of the work is a notion that material failure is governed by the quality of interactions between hierarchical levels in the material microstructure. With intelligent use of the structure, these interactions can be tuned to create a powerful synergetic effect on the material failure behaviour. For example, while exploring different mechanisms of failure initiation in composites with bimodal size reinforcements (an indirect way to model two levels of hierarchy simultaneously) we found that failure initiation could be shifted from stress concentration sites of the higher level to the lower level. One could say that the material behaviour became insensitive to the presence of reinforcements on the higher level—a phenomenon that is counterintuitive to what is commonly known. The new mechanism of failure initiation could only be activated in composites with a highly controlled structural organization—in the studied case, reinforcements of the lower level needed to establish lamellar pathways between reinforcements of the higher level. These pathways lead to formation of an intriguing network-like microstructure. Intelligent communication between reinforcements in such a network created the necessary synergy to change the failure initiation mechanism in a discontinuous fashion. Another finding was that by establishing such a network, tensile stresses near dangerous stress concentration sites were locally transformed into compressive stresses. Resemblance of the revealed mechanism to phenomena on the nano-scale was also discussed. In the course of this work a new method was developed to investigate interactions between reinforcements and their collective input into effective and local properties of a composite. The reinforcement phase was modelled with the use of rigid
A Double Hotspot Model for the Origin of Line Islands Ridge
Pockalny, R. A.; Barth, G. A.; Wertman, C.
2015-12-01
The origin of the various seamount chains in the central Pacific is often difficult to reconstruct due to the number of potential volcanic sources and the criss-crossing patterns associated with plate motion history. One particularly difficult seamount chain to reconstruct is the Line Islands Ridge and the possibly-related Mid-Pacific Mountains and Tuamotu Chain. While the general geographic and age-progressive trends of these features resemble the predicted pattern for Pacific plate motion over the past 120 to 130 My, the relative ages of volcanism along the Line Islands Ridge are not consistent with a conventional hotspot model. To explore potential models of the origin of the Line Islands Ridge, we use GPlates software in conjunction with published seamount dates and known hotspot locations to constrain tectonic reconstructions. Our primary results suggest the Line Islands Ridge was formed by at least two different volcanic sources. The initial source formed the southern section of the Line Island Ridge (4˚N to 1˚S) around 95 to 83 Ma and corresponds to the present-day Crough hotspot. The hotspot also likely generated the linear Boudeuse Ridge (a.k.a. Southern Line Islands) volcanic chain (5˚S to 13˚S) from about 70 to 50 Ma. The second volcanic source, which we call the Larson Hotspot in memory of Roger Larson, formed the northern section of the Line Islands Ridge (7˚N to 4˚N) around 77 to 64 Ma and corresponds to a new "hotspot" region centered on 17˚S and 125˚W near the eastern extension of the Pukapuka Ridge. This source may also account for the formation of the Mid-Pacific Mountains (130 to 105 Ma), the Necker Ridge (105 to 90 Ma), and the later volcanism on the southern section of the Line Island Ridge (65 to 55 Ma). This volcanic source also roughly coincides with the Pukapuka Ridge and more recent volcanism along the same trend, but closer to the East Pacific Rise.
Directory of Open Access Journals (Sweden)
Yanchun Li
Full Text Available Proper development of a seed requires coordinated exchanges of signals among the three components that develop side by side in the seed. One of these is the maternal integument that encloses the other two zygotic components, i.e., the diploid embryo and its nurturing annex, the triploid endosperm. Although the formation of the embryo and endosperm contains the contributions of both maternal and paternal parents, maternally and paternally derived alleles may be expressed differently, leading to a so-called parent-of-origin or imprinting effect. Currently, the nature of how genes from the maternal and zygotic genomes interact to affect seed development remains largely unknown. Here, we present a novel statistical model for estimating the main and interaction effects of quantitative trait loci (QTLs that are derived from different genomes and further testing the imprinting effects of these QTLs on seed development. The experimental design used is based on reciprocal backcrosses toward both parents, so that the inheritance of parent-specific alleles could be traced. The computing model and algorithm were implemented with the maximum likelihood approach. The new strategy presented was applied to study the mode of inheritance for QTLs that control endoreduplication traits in maize endosperm. Monte Carlo simulation studies were performed to investigate the statistical properties of the new model with the data simulated under different imprinting degrees. The false positive rate of imprinting QTL discovery by the model was examined by analyzing the simulated data that contain no imprinting QTL. The reciprocal design and a series of analytical and testing strategies proposed provide a standard procedure for genomic mapping of QTLs involved in the genetic control of complex seed development traits in flowering plants.
Pecot, Thierry; Kervrann, Charles; Bouthemy, P.
2008-01-01
Green Fluorescent Protein (GFP)-tagging and time-lapse fluorescence microscopy enable to observe molecular dynamics and interactions in live cells. Original image analysis methods are then required to process challenging 2D or 3D image sequences. To address the tracking problem of several hundreds of objects, we propose an original framework that provides general information about vesicle transport, that is traffic flows between origin and destination regions detected in the image sequence. T...
Energy Technology Data Exchange (ETDEWEB)
Huerta, M.
1981-06-01
This report describes the mathematical analysis, the physical scale modeling, and a full-scale crash test of a railcar spent-nuclear-fuel shipping system. The mathematical analysis utilized a lumped-parameter model to predict the structural response of the railcar and the shipping cask. The physical scale modeling analysis consisted of two crash tests that used 1/8-scale models to assess railcar and shipping cask damage. The full-scale crash test, conducted with retired railcar equipment, was carefully monitored with onboard instrumentation and high-speed photography. Results of the mathematical and scale modeling analyses are compared with the full-scale test. 29 figures.
Puthen Veettil, Binesh; König, Dirk; Huang, Shujuan; Patterson, Robert; Conibeer, Gavin
2017-02-01
Silicon nanocrystals embedded in a dielectric matrix have been considered a potential candidate for many optoelectronic and photovoltaic applications and have been under vigorous study in recent years. One of the main properties of interest in this application is the absorption bandgap, which is determined by the quantum confinement of silicon nanocrystals. The ability to predict the absorption bandgap is a key step in designing an optimum solar cell using this material. Although several higher level algorithms are available to predict the electronic confinement in these nanocrystals, most of them make regular-shape assumptions for the ease of computation. In this work, we present a model for the accurate prediction of the quantum confinement in silicon nanocrystals of non-regular shape by employing an efficient, self-consistent Full-Multi-Grid method. Confined energies in spherical, elongated, and arbitrarily shaped nanocrystals are calculated. The excited level calculations quantify the wavefunction coupling and energy level splitting arising due to the proximity of dots. The splitting magnitude was found to be as high as 0.1 eV for the 2 nm size silicon quantum dots. The decrease in confinement energy due to the elongation of dots was found to be more than 0.2 eV, and the trend was similar for different dielectric materials. Theoretical predictions were compared to the results from optical and structural characterisation and found to be in agreement. The loss of degeneracy in highly asymmetric quantum dots, such as a "horse-shoe" shaped quantum dot, significantly affects the excited state energies.
Liuzzi, G.; Masiello, G.; Serio, C.; Venafra, S.; Camy-Peyret, C.
2016-10-01
Spectra observed by the Infrared Atmospheric Sounder Interferometer (IASI) have been used to assess both retrievals and the spectral quality and consistency of current forward models and spectroscopic databases for atmospheric gas line and continuum absorption. The analysis has been performed with thousands of observed spectra over sea surface in the Pacific Ocean close to the Mauna Loa (Hawaii) validation station. A simultaneous retrieval for surface temperature, atmospheric temperature, H2O, HDO, O3 profiles and gas average column abundance of CO2, CO, CH4, SO2, N2O, HNO3, NH3, OCS and CF4 has been performed and compared to in situ observations. The retrieval system considers the full IASI spectrum (all 8461 spectral channels on the range 645-2760 cm-1). We have found that the average column amount of atmospheric greenhouse gases can be retrieved with a precision better than 1% in most cases. The analysis of spectral residuals shows that, after inversion, they are generally reduced to within the IASI radiometric noise. However, larger residuals still appear for many of the most abundant gases, namely H2O, CH4 and CO2. The H2O ν2 spectral region is in general warmer (higher radiance) than observations. The CO2ν2 and N2O/CO2ν3 spectral regions now show a consistent behavior for channels, which are probing the troposphere. Updates in CH4 spectroscopy do not seem to improve the residuals. The effect of isotopic fractionation of HDO is evident in the 2500-2760 cm-1 region and in the atmospheric window around 1200 cm-1.
Directory of Open Access Journals (Sweden)
Giancarlo Dall'Ara
2015-11-01
Full Text Available This paper fits within the wider context related to the definition of restoration strategies and models, and revitalization of small historical towns and villages, focusing on touristic use and on the Albergo Diffuso (AD model. This latter, in its functional elements, includes solutions to solve degeneration and gradual depopulation problems, typical in these cases, by enhancing both tangible and intangible resources. The purpose of this research study was to verify, about 20 years after the first implementations, to what extent and by means of what type of intervention the AD model influenced regeneration processes of historical villages and refunctionalization of reused building heritage. By means of an exploratory investigation and an in situ monitoring activity, it was possible to outline an initial measurement of both direct and indirect results following the application of ADs. The activities confirmed the virtuosity of the model and identified both critical issues and strong points, directly connected to the type of users and to the sustainability features of the interventions.
Institute of Scientific and Technical Information of China (English)
刘洛夫; 刘宏江; 王洪玉; 曾溅辉
2002-01-01
There is a type of asphalt that originated from differentiation from reservoir bed (named reservoir bed-differentiated asphalt) in the Silurian asphaltic sandstones of the Tarim Basin. These asphalts are the result of second-time charging of hydrocarbons into the Silurian reservoir, which were derived from Lower Paleozoic source rocks. Asphalt was differentiated from the reservoir bed in the hydrocarbon gathering area of secondary migration. The differen tiation is caused by changes in reservoir physical properties when pearl or chain hydrocarbons migrating through and gathering in the reservoir bed, and light components are lost and heavy ones are involved in the formation of asphalt or heavy oil. There are two kinds of occurrence of these asphalts in the Silurian system of the Tarim Basin. One is the poor heavy oil layer with lower oil saturation in trap and the other is scattered hydrocarbon distributed along the transport layer and unconformity surface. Reservoir bed-differentiated asphalts have two characteristics: total hydrocarbon content is high in extractable organic matter and the ratio of saturated to aromatic hydrocarbon is usually greater than unity. The physically modeling experiment has confirmed these characteristics and the genesis of the reservoir bed-differentiated asphalts.
Institute of Scientific and Technical Information of China (English)
刘洛夫; 刘宏江; 等
2002-01-01
There is a type of asphalt that originated from differentiation from reservoir bed (named reservoir bed-differentiated asphalt)in the Silurian asphaltic sandstones of the Tarim Basin.These asphalts are the result of second-time charging of hydrocarbons into the Silurian reservoir,which were derived from Lower Paleozoic source rocks.Asphalt was differentiated from the reservoir bed in the hydrocarbon gathering area of secondary migration.The different-tiation is caused by changes in reservoir physical properties when pearl or chain hydrocarbons migrating through and gathering in the reservoir bed,and light components are lost and heavy ones are involved in the formation of asphalt or heavy oil.There are two kinds of occurrence of these asphalts in the Silurian system of the Tarim Basin.One is the poor heavy oil layer with lower oil saturation in trap and the other is scattered hydrocarbon distributed along the trans-port layer and unconformity surface.Reservoir bed-differentiated asphalts have two characteris-tics:total hydrocarbon content is high in extractable organic matter and the ratio of saturated to aromatic hydrocarbon is usually greater than unity.The physically modeling experiment has confirmed these characteristics and the genesis of the reservoir bed-differentiated asphalts.
Dynamical Clustering and the Origin of Raft-like Structures in a Model Lipid Membrane
Starr, Francis
2014-03-01
We investigate the dynamical heterogeneity of a model single-component lipid membrane using simulations of a coarse-grained representation of lipid molecules. In the liquid-ordered (LO) phase, lipid diffusion is hindered by the transient trapping of molecules by their neighbors, giving rise to two distinct mobility groups: low-mobility lipids which are temporarily ``caged'', and lipids with displacements on the scale of the intermolecular spacing. The lipid molecules within these distinct mobility states cluster, giving rise to transient ``islands'' of enhanced mobility having the size and time scale expected for lipid ``rafts''. These clusters are strikingly similar to the dynamical clusters found in glass-forming fluids, and distinct from phase-separation clusters. Such dynamic heterogeneity is ubiquitous in disordered condensed-phase systems. Thus, we hypothesize that rafts may originate from this universal mechanism, explaining why raft-like regions should arise, regardless of lipid structural or compositional details. This perspective provides a new approach to understand membrane transport.
The Standard Model Higgs as the origin of the hot Big Bang
Figueroa, Daniel G.
2017-04-10
If the Standard Model (SM) Higgs is weakly coupled to the inflationary sector, the Higgs is expected to be universally in the form of a condensate towards the end of inflation. The Higgs decays rapidly after inflation -- via non-perturbative effects -- into an out-of-equilibrium distribution of SM species, which thermalize soon afterwards. If the post-inflationary equation of state of the universe is stiff, $w \\simeq +1$, the SM species eventually dominate the total energy budget. This provides a natural origin for the relativistic thermal plasma of SM species, required for the onset the `hot Big Bang' era. The viability of this scenario requires the inflationary Hubble scale $H_*$ to be lower than the instability scale for Higgs vacuum decay, the Higgs not to generate too large curvature perturbations at cosmological scales, and the SM dominance to occur before Big Bang Nucleosynthesis. We show that successful reheating into the SM can only be obtained in the presence of a non-minimal coupling to gravity $\\x...
A multidimensional analysis of the epistemic origins of nursing theories, models, and frameworks.
Beckstead, Jason W; Beckstead, Laura Grace
2006-01-01
The purpose of this article is to introduce our notion of epistemic space and to demonstrate its utility for understanding the origins and trajectories of nursing theory in the 20th century using multidimensional scaling (MDS). A literature review was conducted on primary and secondary sources written by and about 20 nurse theorists to investigate whether or not they cited 129 different scholars in the fields of anthropology, biology, nursing, philosophy, psychology, and sociology. Seventy-four scholars were identified as having been cited by at least two nurse theorists (319 citations total). Proximity scores, quantifying the similarity among nurse theorists based on proportions of shared citations, were calculated and analyzed using MDS. The emergent model of epistemic space that accommodated these similarities among nurse theorists revealed the systematic influence of scholars from various fields, notably psychology, biology, and philosophy. We believe that this schema and resulting taxonomy will prove useful for furthering our understanding of the relationships among nursing theories and theories in other fields of science.
A developmental-contextual model of depressive symptoms in Mexican-origin female adolescents.
Bámaca-Colbert, Mayra Y; Umaña-Taylor, Adriana J; Gayles, Jochebed G
2012-03-01
The current study tested a developmental-contextual model of depressive symptomatology among Mexican-origin, female early and middle adolescents and their mothers. The final sample comprised 271 dyads. We examined the interrelations among cultural (i.e., acculturation dissonance), developmental (i.e., pubertal development and autonomy expectation discrepancies), and interpersonal (i.e., mother-daughter conflict and maternal supportive parenting) factors in predicting adolescents' depressive symptoms. For both early and middle adolescents, maternal support was negatively associated with mother-daughter conflict and depressive symptoms. Mother-daughter autonomy expectation discrepancies were positively associated with mother-daughter conflict, but this association was found only among early adolescents. Further, mother-daughter acculturation dissonance was positively associated with mother-daughter conflict but only among middle adolescents. Findings call for concurrently examining the interface of developmental, relational, and cultural factors in predicting female adolescents' depressive symptomatology and the potential differences by developmental stage (e.g., early vs. middle adolescence). PsycINFO Database Record (c) 2012 APA, all rights reserved.
The Standard Model Higgs as the origin of the hot Big Bang
Figueroa, Daniel G.; Byrnes, Christian T.
2017-04-01
If the Standard Model (SM) Higgs is weakly coupled to the inflationary sector, the Higgs is expected to be universally in the form of a condensate towards the end of inflation. The Higgs decays rapidly after inflation - via non-perturbative effects - into an out-of-equilibrium distribution of SM species, which thermalize soon afterwards. If the post-inflationary equation of state of the universe is stiff, w ≃ + 1, the SM species eventually dominate the total energy budget. This provides a natural origin for the relativistic thermal plasma of SM species, required for the onset of the 'hot Big Bang' era. The viability of this scenario requires the inflationary Hubble scale H* to be lower than the instability scale for Higgs vacuum decay, the Higgs not to generate too large curvature perturbations at cosmological scales, and the SM dominance to occur before Big Bang Nucleosynthesis. We show that successful reheating into the SM can only be obtained in the presence of a non-minimal coupling to gravity ξ ≳ 1, with a reheating temperature of TRH ≳ O (1010)ξ 3 / 2(H* /1014 GeV) 2 GeV.
A critical assessment of models for the origin of multiple populations in globular clusters
Bastian, Nate
2017-03-01
A number of scenarios have been put forward to explain the origin of the chemical anomalies (and resulting complex colour-magnitude diagrams) observed in globular clusters (GCs), namely the AGB, Fast Rotating Massive Star, Very Massive Star, and Early Disc Accretion scenarios. We compare the predictions of these scenarios with a range of observations (including young massive clusters (YMCs), chemical patterns, and GC population properties) and find that all models are inconsistent with observations. In particular, YMCs do not show evidence for multiple epochs of star-formation and appear to be gas free by an age of ~ 3 Myr. Also, the chemical patterns displayed in GCs vary from one to the next in such a way that cannot be reproduced by standard nucleosynthetic yields. Finally, we show that the ``mass budget problem'' for the scenarios cannot be solved by invoking heavy cluster mass loss (i.e. that clusters were 10-100 times more massive at birth) as this solution makes basic predictions about the GC population that are inconsistent with observations. We conclude that none of the proposed scenarios can explain the multiple population phenomenon, hence alternative theories are needed.
A critical assessment of models for the origin of multiple populations in globular clusters
Bastian, Nate
2015-01-01
A number of scenarios have been put forward to explain the origin of the chemical anomalies (and resulting complex colour-magnitude diagrams) observed in globular clusters (GCs), namely the AGB, Fast Rotating Massive Star, Very Massive Star, and Early Disc Accretion scenarios. We compare the predictions of these scenarios with a range of observations (including young massive clusters (YMCs), chemical patterns, and GC population properties) and find that all models are inconsistent with observations. In particular, YMCs do not show evidence for multiple epochs of star-formation and appear to be gas free by an age of ~3 Myr. Also, the chemical patterns displayed in GCs vary from one to the next in such a way that cannot be reproduced by standard nucleosynthetic yields. Finally, we show that the "mass budget problem" for the scenarios cannot be solved by invoking heavy cluster mass loss (i.e. that clusters were 10-100 times more massive at birth) as this solution makes basic predictions about the GC population t...
Hierarchical model of natural images and the origin of scale invariance.
Saremi, Saeed; Sejnowski, Terrence J
2013-02-19
The study of natural images and how our brain processes them has been an area of intense research in neuroscience, psychology, and computer science. We introduced a unique approach to studying natural images by decomposing images into a hierarchy of layers at different logarithmic intensity scales and mapping them to a quasi-2D magnet. The layers were in different phases: "cold" and ordered at large-intensity scales, "hot" and disordered at small-intensity scales, and going through a second-order phase transition at intermediate scales. There was a single "critical" layer in the hierarchy that exhibited long-range correlation similar to that found in the 2D Ising model of ferromagnetism at the critical temperature. We also determined the interactions between layers mapped from natural images and found mutual inhibition that generated locally "frustrated" antiferromagnetic states. Almost all information in natural images was concentrated in a few layers near the phase transition, which has biological implications and also points to the hierarchical origin of scale invariance in natural images.
Probing the origins of human acetylcholinesterase inhibition via QSAR modeling and molecular docking
Shoombuatong, Watshara; Malik, Aijaz Ahmad; Prachayasittikul, Virapong; Wikberg, Jarl E.S.
2016-01-01
Alzheimer’s disease (AD) is a chronic neurodegenerative disease which leads to the gradual loss of neuronal cells. Several hypotheses for AD exists (e.g., cholinergic, amyloid, tau hypotheses, etc.). As per the cholinergic hypothesis, the deficiency of choline is responsible for AD; therefore, the inhibition of AChE is a lucrative therapeutic strategy for the treatment of AD. Acetylcholinesterase (AChE) is an enzyme that catalyzes the breakdown of the neurotransmitter acetylcholine that is essential for cognition and memory. A large non-redundant data set of 2,570 compounds with reported IC50 values against AChE was obtained from ChEMBL and employed in quantitative structure-activity relationship (QSAR) study so as to gain insights on their origin of bioactivity. AChE inhibitors were described by a set of 12 fingerprint descriptors and predictive models were constructed from 100 different data splits using random forest. Generated models afforded R2, \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${Q}_{\\mathrm{CV }}^{2}$\\end{document}QCV2 and \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${Q}_{\\mathrm{Ext}}^{2}$\\end{document}QExt2 values in ranges of 0.66–0.93, 0.55–0.79 and 0.56–0.81 for the training set, 10-fold cross-validated set and external set, respectively. The best model built using the substructure count was selected according to the OECD guidelines and it afforded R2, \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage
García-Díez, Markel; Lauwaet, Dirk; Hooyberghs, Hans; Ballester, Joan; De Ridder, Koen; Rodó, Xavier
2016-12-01
As most of the population lives in urban environments, the simulation of the urban climate has become a key problem in the framework of the climate change impact assessment. However, the high computational power required by high-resolution (sub-kilometre) fully coupled land-atmosphere simulations using urban canopy parameterisations is a severe limitation. Here we present a study on the performance of UrbClim, an urban boundary layer model designed to be several orders of magnitude faster than a full-fledged mesoscale model. The simulations are evaluated with station data and land surface temperature observations from satellites, focusing on the urban heat island (UHI). To explore the advantages of using a simple model like UrbClim, the results are compared with a simulation carried out with a state-of-the-art mesoscale model, the Weather Research and Forecasting Model, which includes an urban canopy model. This comparison is performed with driving data from ERA-Interim reanalysis (70 km). In addition, the effect of using driving data from a higher-resolution forecast model (15 km) is explored in the case of UrbClim. The results show that the performance of reproducing the average UHI in the simple model is generally comparable to the one in the mesoscale model when driven with reanalysis data (70 km). However, the simple model needs higher-resolution data from the forecast model (15 km) to correctly reproduce the variability of the UHI at a daily scale, which is related to the wind speed. This lack of accuracy in reproducing the wind speed, especially the sea-breeze daily cycle, which is strong in Barcelona, also causes a warm bias in the reanalysis driven UrbClim run. We conclude that medium-complexity models as UrbClim are a suitable tool to simulate the urban climate, but that they are sensitive to the ability of the input data to represent the local wind regime. UrbClim is a well suited model for impact and adaptation studies at city scale without high
What Are the Origins of Detached Layers of Dust on Mars ? Investigation with Global Climate Model
Bertrand, T.; Spiga, A.; Forget, F.
2014-12-01
The climate on Mars is strongly controlled by the amount of dust lifted and transported in the atmosphere, which causes fluctuations of air opacity and affects temperatures and winds. Recently, observations of the vertical dust distribution of the Martian atmosphere by the Mars Climate Sounder on board the Mars Reconnaissance Orbiter revealed a phenomenon which is still poorly understood: the formation of detached layers of dust. These detached layers, also confirmed by the Thermal Emission Spectrometer on-board the Mars Global Surveyor, reside above the planetary boundary layer typically at altitudes between 20 and 40 km and have been mostly observed at low latitudes. These detached layers of dust are not reproduced by Global Climate Models (GCM) and different atmospheric processes are discussed and can be combined to explain their origin, such as small-scale lifting, upslope topographic winds, scavenging by water ice clouds, dust storms… Here we use the Martian GCM developed at the Laboratoire de Météorologie Dynamique (LMD) to simulate the formation of detached layers of dust. To start, we developed a new implementation of the water cycle, taking into account nucleation on dust particles, ice particle growth, and scavenging of dust particles due to the condensation of ice. However, this method didn't yield to satisfying results in the GCM. Then, we performed the parameterization in the GCM of the so-called "rocket dust storms", governed by deep convection and able to inject dust at high altitudes in the Martian troposphere. By coupling this new parameterization with general circulation of the GCM, we succeed to model detached layers of dust. Here we present this parameterization and we discuss about the spatial and temporal variability of the detached layers of dust, in comparison with observations.
Alexis, Nutz; Pierre, Dietrich; Vafe, Soumahoro; Mathieu, Schuster; Jean-François, Ghienne
2016-04-01
Deltas simultaneously respond to modifications in parameters such as water discharge, sediment supply and base-level change. Those parameters are driven by a number of potential external forcing processes, nevertheless mainly corresponding to tectonism and climate. In this study, geomorphology and numerical modeling are coupled in order to provide analysis of the delta complex of the Turkwel River (Lake Turkana, Kenya). The Turkwel delta complex is 35 km long, forming one of the major deltaic systems that has fringed Lake Turkana during the Holocene. It developed during the lake level regression at the end of the holocene African Humid Period and correspond to a typical forced-regressive delta. Trajectory analysis was performed on three transects cross-cutting the deltaic complex. Transects consistently display five slightly descending (slope gradient: >0° to 0.4°) plateaus separated by four abrupt steps of higher slope gradients (1° to 3.8°). Conventional interpretations presume that the deltaic trajectory results from either (1) four abrupt accelerations in lake level fall during the continuous regression, (2) four abrupt declines in sediment supply and/or water discharge during a steady lake level fall or (3) a combination of both. We used numerical stratigraphic modeling (Dionisos) in order to test the aforementioned hypotheses as the origin of observed trajectories. We concluded that causal relationships between sediment supply, lake level change and progradation trajectory are not as straightforward as recurrently envisioned. We think that this contribution brings new lights on the relationships between deltaic architectures and controlling factors.
Origin of the "Odessa tsunami" of 27 June 2014: Data assessment and numerical modelling
Sepic, Jadranka; Rabinovich, Alexander B.; Sytov, Victor N.
2016-04-01
During 23 to 27 June 2014, several locations in the Mediterranean and the Black Sea were hit by destructive tsunami-like waves. Analysis of synoptic conditions, air pressure and sea level records indicated that all these events were meteorological tsunamis, i.e. tsunami-like waves generated by short-lasting (a few tens of minutes) but intense air pressure disturbances. The north-western Black Sea was one of the regions impacted: at approximately noon on 27 June a 1-2 m high wave struck the beaches of Odessa, the third largest Ukrainian city, and the neighbouring port-town Illichevsk. Several people were injured and taken to hospital. Throughout the day, a distinct meteotsunamigenic synoptic pattern, accompanied by pronounced air pressure oscillations, was observed over the Black Sea, 150 to 300 km south of Odessa, stretching from Romania in the west to Crimea in the east. Right at the time of the event, a 1-2 hPa air pressure jump was recorded at Odessa. We have utilized a barotropic ocean numerical model to test two hypothesis: (1) a tsunami-like wave was generated by an air pressure disturbance propagating directly over Odessa; (2) a tsunami-like wave was generated by an air pressure disturbance propagating off-shore, approximately 200 km to the south of Odessa. Surprisingly, 1.5 times higher maximum modelled sea level heights in Odessa were obtained in the second set of experiments. The resulting increase was 10 cm per 1 hPa of air pressure change for an offshore disturbance and 7 cm per 1 hPa for a direct forcing experiment. The numerical model decisively confirms the meteorological origin of the tsunami-like waves on the coast of Odessa and implies that intensified long-ocean waves in this region were generated via the Proudman resonance mechanism while propagating over the northwestern Black Sea shelf. Upon hitting the shelf-break, modelled ocean waves detached from the air pressure disturbance and reflected northwards. Following the reflection, the waves
Directory of Open Access Journals (Sweden)
Peter Civáň
Full Text Available We used supernetworks with datasets of nuclear gene sequences and novel markers detecting retrotransposon insertions in ribosomal DNA loci to reassess the evolutionary relationships among tetraploid wheats. We show that domesticated emmer has a reticulated genetic ancestry, sharing phylogenetic signals with wild populations from all parts of the wild range. The extent of the genetic reticulation cannot be explained by post-domestication gene flow between cultivated emmer and wild plants, and the phylogenetic relationships among tetraploid wheats are incompatible with simple linear descent of the domesticates from a single wild population. A more parsimonious explanation of the data is that domesticated emmer originates from a hybridized population of different wild lineages. The observed diversity and reticulation patterns indicate that wild emmer evolved in the southern Levant, and that the wild emmer populations in south-eastern Turkey and the Zagros Mountains are relatively recent reticulate descendants of a subset of the Levantine wild populations. Based on our results we propose a new model for the emergence of domesticated emmer. During a pre-domestication period, diverse wild populations were collected from a large area west of the Euphrates and cultivated in mixed stands. Within these cultivated stands, hybridization gave rise to lineages displaying reticulated genealogical relationships with their ancestral populations. Gradual movement of early farmers out of the Levant introduced the pre-domesticated reticulated lineages to the northern and eastern parts of the Fertile Crescent, giving rise to the local wild populations but also facilitating fixation of domestication traits. Our model is consistent with the protracted and dispersed transition to agriculture indicated by the archaeobotanical evidence, and also with previous genetic data affiliating domesticated emmer with the wild populations in southeast Turkey. Unlike other
Seo, Hyeon; Kim, Donghyeon; Jun, Sung Chan
2016-06-01
Electrical brain stimulation (EBS) is an emerging therapy for the treatment of neurological disorders, and computational modeling studies of EBS have been used to determine the optimal parameters for highly cost-effective electrotherapy. Recent notable growth in computing capability has enabled researchers to consider an anatomically realistic head model that represents the full head and complex geometry of the brain rather than the previous simplified partial head model (extruded slab) that represents only the precentral gyrus. In this work, subdural cortical stimulation (SuCS) was found to offer a better understanding of the differential activation of cortical neurons in the anatomically realistic full-head model than in the simplified partial-head models. We observed that layer 3 pyramidal neurons had comparable stimulation thresholds in both head models, while layer 5 pyramidal neurons showed a notable discrepancy between the models; in particular, layer 5 pyramidal neurons demonstrated asymmetry in the thresholds and action potential initiation sites in the anatomically realistic full-head model. Overall, the anatomically realistic full-head model may offer a better understanding of layer 5 pyramidal neuronal responses. Accordingly, the effects of using the realistic full-head model in SuCS are compelling in computational modeling studies, even though this modeling requires substantially more effort.
Directory of Open Access Journals (Sweden)
Helder Gomes Rodrigues
2015-09-01
Full Text Available Unravelling the evolutionary and developmental mechanisms that have impacted the mammalian dentition, since more than 200 Ma, is an intricate issue. Interestingly, a few mammal species, including the silvery mole-rat Heliophobius argenteocinereus, are able to replace their dentition by the addition of supernumerary molars at the back of jaw migrating then toward the front. The aim here was to demonstrate the potential interest of further studying this rodent in order to better understand the origins of continuous dental replacement in mammals, which could also provide interesting data concerning the evolution of limited dental generation occurring in first mammals. In the present study, we described the main stages of the dental eruptive sequence in the silvery mole-rat and the associated characteristics of horizontal replacement using X-ray microtomography. This was coupled to the investigation of other African mole-rats which have no dental replacement. This method permitted to establish evidence that the initial development of the dentition in Heliophobius is comparable to what it is observed in most of African mole-rats. This rodent first has premolars, but then identical additional molars, a mechanism convergent to manatees and the pygmy rock-wallaby. Evidence of continuous replacement and strong dental dynamics were also illustrated in Heliophobius, and stressed the need to deeply investigate these aspects for evolutionary, functional and developmental purposes. We also noticed that two groups of extinct non-mammalian synapsids convergently acquired this dental mechanism, but in a way differing from extant mammals. The discussion on the diverse evolutionary origins of horizontal dental replacement put emphasis on the necessity of focusing on biological parameters potentially involved in both continuous and limited developments of teeth in mammals. In that context, the silvery mole-rat could appear as the most appropriate candidate to do so.
Energy Technology Data Exchange (ETDEWEB)
Schafer, M
2004-09-01
Although experimental results so far agree with predictions of the standard model, it is widely felt to be incomplete. Many prospective theories beyond the standard model predict extra neutral gauge bosons, denoted by Z', which might be light enough to be accessible at the LHC. Observables sensitive to the properties of these extra gauge bosons might be used to discriminate between the different theories beyond the standard model. In the present work several of these observables (total decay width, leptonic cross-section and forward-backward asymmetries) are studied at generation level and with a full simulation in the ATLAS detector. The Z' {yields} e{sup +}e{sup -} decay channel was chosen and 2 values for the mass of Z': 1.5 TeV and 4 TeV. Background is studied as well and it is confirmed that a Z' boson could easily be discovered at the chosen masses. It is shown that even in full simulation the studied observables can be determined with a good precision. In a next step a discrimination strategy has to be developed given the presented methods to extract the variables and their precision. (author)
Analysing the origin of long-range interactions in proteins using lattice models
Directory of Open Access Journals (Sweden)
Unger Ron
2009-01-01
Full Text Available Abstract Background Long-range communication is very common in proteins but the physical basis of this phenomenon remains unclear. In order to gain insight into this problem, we decided to explore whether long-range interactions exist in lattice models of proteins. Lattice models of proteins have proven to capture some of the basic properties of real proteins and, thus, can be used for elucidating general principles of protein stability and folding. Results Using a computational version of double-mutant cycle analysis, we show that long-range interactions emerge in lattice models even though they are not an input feature of them. The coupling energy of both short- and long-range pairwise interactions is found to become more positive (destabilizing in a linear fashion with increasing 'contact-frequency', an entropic term that corresponds to the fraction of states in the conformational ensemble of the sequence in which the pair of residues is in contact. A mathematical derivation of the linear dependence of the coupling energy on 'contact-frequency' is provided. Conclusion Our work shows how 'contact-frequency' should be taken into account in attempts to stabilize proteins by introducing (or stabilizing contacts in the native state and/or through 'negative design' of non-native contacts.
Directory of Open Access Journals (Sweden)
A. Réchou
2013-02-01
Full Text Available Orography is a well-known source of gravity and inertia-gravity waves in the atmosphere. Other sources, such as convection, are also known to be potentially important but the large amplitude of orographic waves over Scandinavia has generally precluded the possibility to study such other sources experimentally in this region. In order to better understand the origin of stratospheric gravity waves observed by the VHF radar ESRAD (Esrange MST radar over Kiruna, in Arctic Sweden (67.88° N, 21.10° E, observations have been compared to simulations made using the Weather Research and Forecasting model (WRF with and without the effects of orography and clouds. This case study concerns gravity waves observed from 00:00 UTC on 18 February to 12:00 UTC on 20 February 2007. We focus on the wave signatures in the static stability field and vertical wind deduced from the simulations and from the observations as these are the parameters which are provided by the observations with the best height coverage. As is common at this site, orographic gravity waves were produced over the Scandinavian mountains and observed by the radar. However, at the same time, southward propagation of fronts in the Barents Sea created short-period waves which propagated into the stratosphere and were transported, embedded in the cyclonic winds, over the radar site.
Magmatic Conduit Metallogenic System - A New Model for the Origin of Ore-deposits
Su, S.; Tang, Z.; Wu, G.; Deng, J.; Xiao, Q.; Luo, Z.; Cui, Y.
2013-12-01
Origin and emplacement processes of ore-deposits connected with intrusions remains poorly understood. Here we propose a new model 'Magmatic Conduit Metallogenic System' to explain the origin of ore-deposits. Magmatic flow (or Melt-fluid flow) bearing metals will finally settle in the conduits at later stage of magma evolved in magma metallogenic system. Magmatic flow (or Melt-fluid flow) bearing metals include many types, such as sulfide melts and iron melts bearing fluids. Conduits will form along the zones of structural weakness, such as fault zone and interface of two different types of rocks. These conduits are usually very complicated in the magmatic system, exemplified by two typical ore-deposits, detailed as follows. The Jinchuan sulfide deposit, located in Gansu Province, China, is the third largest magmatic Cu-Ni Platinum Group Elements (PGE) in the world. There are mainly four orebodies (orebody 58, 24, 1, and 2) from west to east, with Ni/Cu value at 1.24, 1.56, 1.83 and 2.06 respectively; the content of Pt+Pd ranges from 0.4 to 10.3 ppm, with the highest value occurs in the west. This suggests that the direction of the melt flow bearing sulfide is from west to east and the front of the conduit system is in the east part of the deposit. Sulfide segregation in the magmatic chamber or in the conduits might have caused ore content to change in different part of the conduit systems. Another typical example is the Xishimen iron deposit, which is located in the South of Hebei Province, China. It has been considered as a skarn-type iron deposit conventionally. However, many geological evidence suggests that Xishimen iron deposit is a magmatic iron deposit instead. Such evidence includes: 1. The boundaries between iron orebodies and country rocks are obvious, no transitional relationship; 2. Iron ore body injected into the country rocks (including genesis, diorite, and marble); 3. There are some vesicular in the iron ores; 4. Magnetite as an interstitial mineral
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Naomi Lewin
Full Text Available GABA is the key inhibitory neurotransmitter in the adult central nervous system, but in some circumstances can lead to a paradoxical excitation that has been causally implicated in diverse pathologies from endocrine stress responses to diseases of excitability including neuropathic pain and temporal lobe epilepsy. We undertook a computational modeling approach to determine plausible ionic mechanisms of GABA(A-dependent excitation in isolated post-synaptic CA1 hippocampal neurons because it may constitute a trigger for pathological synchronous epileptiform discharge. In particular, the interplay intracellular chloride accumulation via the GABA(A receptor and extracellular potassium accumulation via the K/Cl co-transporter KCC2 in promoting GABA(A-mediated excitation is complex. Experimentally it is difficult to determine the ionic mechanisms of depolarizing current since potassium transients are challenging to isolate pharmacologically and much GABA signaling occurs in small, difficult to measure, dendritic compartments. To address this problem and determine plausible ionic mechanisms of GABA(A-mediated excitation, we built a detailed biophysically realistic model of the CA1 pyramidal neuron that includes processes critical for ion homeostasis. Our results suggest that in dendritic compartments, but not in the somatic compartments, chloride buildup is sufficient to cause dramatic depolarization of the GABA(A reversal potential and dominating bicarbonate currents that provide a substantial current source to drive whole-cell depolarization. The model simulations predict that extracellular K(+ transients can augment GABA(A-mediated excitation, but not cause it. Our model also suggests the potential for GABA(A-mediated excitation to promote network synchrony depending on interneuron synapse location - excitatory positive-feedback can occur when interneurons synapse onto distal dendritic compartments, while interneurons projecting to the perisomatic
A model for the origin and properties of flicker-induced geometric phosphenes.
Directory of Open Access Journals (Sweden)
Michael Rule
2011-09-01
Full Text Available We present a model for flicker phosphenes, the spontaneous appearance of geometric patterns in the visual field when a subject is exposed to diffuse flickering light. We suggest that the phenomenon results from interaction of cortical lateral inhibition with resonant periodic stimuli. We find that the best temporal frequency for eliciting phosphenes is a multiple of intrinsic (damped oscillatory rhythms in the cortex. We show how both the quantitative and qualitative aspects of the patterns change with frequency of stimulation and provide an explanation for these differences. We use Floquet theory combined with the theory of pattern formation to derive the parameter regimes where the phosphenes occur. We use symmetric bifurcation theory to show why low frequency flicker should produce hexagonal patterns while high frequency produces pinwheels, targets, and spirals.
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Kuznetsov Vladimir V.
2016-01-01
Full Text Available New full-statement 3D mathematical model of joint motion of thin liquid film and gas in a microchannel at local heating developed by taking into account the heat transfer by flows, evaporation and condensation, as well as the heat transfer at the gas-liquid interface is derived. The model is based on the full system of the Navier-Stokes equations, taking into account the convective terms of motion equations in the phases. Comparison of the numerical results obtained using the model based on the full Navier-Stokes equations and using the simplified model developed in the framework of the thin layer approximation has been performed. The comparison shows that at low Reynolds numbers, simplified model well describes all the main characteristics of the gas and liquid motion. With the gas Reynolds numbers significant increase difference between numerical results starts to grow.
DEFF Research Database (Denmark)
Mbamba, Christian Kazadi; Flores Alsina, Xavier; Batstone, Damien John
2016-01-01
The focus of modelling in wastewater treatment is shifting from single unit to plant-wide scale. Plant wide modelling approaches provide opportunities to study the dynamics and interactions of different transformations in water and sludge streams. Towards developing more general and robust simula...
Akkermans, Joost; Payne, Beth; von Dadelszen, Peter; Groen, Henk; de Vries, Johanna; Magee, Laura A.; Mol, Ben Willem; Ganzevoort, Wessel
2014-01-01
Objective: The internally validated fulIPIERS model predicts adverse maternal outcomes in women with pre-eclampsia within 48 h after eligibility. Our objective was to assess generalizability of this prediction model. Study design: External validation study using prospectively collected data from two
Directory of Open Access Journals (Sweden)
Wendy J. Huss
2007-11-01
Full Text Available Following castration, the transgenic adenocarcinoma of mouse prostate (TRAMP model demonstrates rapid development of SV40-Tag-driven poorly differentiated tumors that express neuroendocrine cell markers. The cell population dynamics within the prostates of castrated TRAMP mice were characterized by analyzing the incorporation of 5-bromodeoxyuridine (BrdUrd and the expression of SV40-Tag, synaptophysin, and androgen receptor (AR. Fourteen days postcastration, the remaining epithelial cells and adenocarcinoma cells were nonproliferative and lacked detectable SV40-Tag or synaptophysin expression. In contrast, morphologically distinct intraglandular foci were identified which expressed SV40-Tag, synaptophysin, and Ki67, but that lacked AR expression. These proliferative SV40-Tag and synaptophysin-expressing intraglandular foci were associated with the rare BrdUrd-retaining cells. These foci expanded rapidly in the postcastration prostate environment, in contrast to the AR- and SV40-Tag-expressing adenocarcinoma cells that lost SV40-Tag expression and underwent apoptosis after castration. Intraglandular foci of synaptophysin-expressing cells were also observed in the prostates of intact TRAMP mice at a comparable frequency; however, they did not progress to rapidly expanding tumors until much later in the life of the mice. This suggests that the foci of neuroendocrine-like cells that express SV40-Tag and synaptophysin, but lack AR, arise independent of androgen-deprivation and represent the source of the poorly differentiated tumors that are the lethal phenotype in the TRAMP model.
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S. H. Li
2014-01-01
Full Text Available Under complicated driving situations, such as cornering brake, lane change, or barrier avoidance, the vertical, lateral, and longitudinal dynamics of a vehicle are coupled and interacted obviously. This work aims to propose the suitable vehicle and driver models for researching full vehicle dynamics in complicated conditions. A nonlinear three-directional coupled lumped parameters (TCLP model of a heavy-duty vehicle considering the nonlinearity of suspension damping and tire stiffness is built firstly. Then a modified preview driver model with nonlinear time delay is proposed and connected to the TCLP model to form a driver-vehicle closed-loop system. The presented driver-vehicle closed-loop system is evaluated during a double-lane change and compared with test data, traditional handling stability vehicle model, linear full vehicle model, and other driver models. The results show that the new driver model has better lane keeping performances than the other two driver models. In addition, the effects of driver model parameters on lane keeping performances, handling stability, ride comfort, and roll stability are discussed. The models and results of this paper are useful to enhance understanding the effects of driver behaviour on full vehicle dynamics.
Djellouli, Rabia
2017-01-01
We propose a computational strategy that falls into the category of prediction/correction iterative-type approaches, for calibrating the hemodynamic model introduced by Friston et al. (2000). The proposed method is employed to estimate consecutively the values of the biophysiological system parameters and the external stimulus characteristics of the model. Numerical results corresponding to both synthetic and real functional Magnetic Resonance Imaging (fMRI) measurements for a single stimulus as well as for multiple stimuli are reported to highlight the capability of this computational methodology to fully calibrate the considered hemodynamic model.
Zambri, Brian
2017-02-22
We propose a computational strategy that falls into the category of prediction/correction iterative-type approaches, for calibrating the hemodynamic model introduced by Friston et al. (2000). The proposed method is employed to estimate consecutively the values of the biophysiological system parameters and the external stimulus characteristics of the model. Numerical results corresponding to both synthetic and real functional Magnetic Resonance Imaging (fMRI) measurements for a single stimulus as well as for multiple stimuli are reported to highlight the capability of this computational methodology to fully calibrate the considered hemodynamic model. This article is protected by copyright. All rights reserved.
Sivanandan, R.; Nanda, Dhruv
1998-01-01
The conventional methods of determining origin-destination (O-D) trip tables involve elaborate surveys, e.g., home interviews, that require considerable time, staff, and funds. To overcome this drawback, a number of theoretical models that synthesize O-D trip tables from link volume data have been developed. The focus of the research reported here was on two of these models The Highway Emulator (THE) and the Linear Programming (LP) model. These models use target/seed tables for guiding the de...
DEFF Research Database (Denmark)
Neergaard, Jesper; Schieber, Jay D.
1999-01-01
A self-consistent reptation model that includes chain stretching, chain-length fluctuations, segment connectivity and constraint release is used to predict transient and steady flows. Quantitative comparisons are made with entangledsolution data. The model is able to capture quantitatively all fe...... for differentmolecular weight, the transient and steady-state behavior of the extinction angle, and the stress relaxation in cessation of steady shear flow....
Gilmore, M. S.
1999-01-01
Measurements recently supplied by the MGS Magnetometer/Electron Reflectometer (MAG/ER) on MGS can be applied to test theories of the origin of the martian crustal dichotomy. Strong (+/- 1500 nT) magnetic anomalies are observed in the Martian crust. The observations can be summarized as follows: 1) strong crustal magnetic sources are generally confined to the southern highlands, although weaker (approx. 40 nT) anomalies were observed during close periapsis; 2) strong magnetic anomalies are absent in the vicinity of Hellas and Argyre; 3) the anomalies in the region 0 deg to 90 deg S, 120 deg to 240 deg west have a linear geometry, strike generally east west for 1000s km, and show several reversals. This latter point has led to the suggestion that some form of lateral plate tectonics may have been operative in the southern highlands of Mars. These observations have led previous workers to hypothesize that the magnetic anomalies were present prior to and were destroyed by the formation of Hellas and Argyre. As such large impacts are confined to the era of heavy bombardment, this places the time of formation of large magnetic anomalies prior to approx. 3.9 Ga. One obvious extension of this is that the northern lowlands lack significant anomalies because they were erased by impacts and/or the northern lowlands represent crust completely reheated above the Curie temperature. Preliminary observations of the distributions of the large crustal magnetic anomalies show that many of them extend continuously over the highland lowland boundary. This occurs particularly north of the boundary between 30 deg W and 270 deg W, corresponding to northern Arabia, but also occurs in southern Elysium (approx. 10 deg S, 200 deg) and the SW portion of Tharsis (approx. 15 deg S, 140 deg). This suggests that, in these areas, Noachian crust containing the greater than 3.9 Ga magnetic signature, lies beneath the northern highlands. This geometry can be used to test models for the formation of
Quantum origins of the Iczkowski-Margrave model of chemical potential
Energy Technology Data Exchange (ETDEWEB)
Valone, Steven M [Los Alamos National Laboratory
2010-01-01
Charge flow in materials is controlled at the atomistic level through some model of the chemical potential, such as the Iczkowski-Margrave (IM) model. This model is built largely on heuristic arguments. Here a model Hamiltonian is constructed at the atomistic level commensurate with the IM model. Essential properties of the model Hamiltonian are presented, including a possible revision of the charge dependence in the IM model. Transitional properties of the model are shown to be central to regulating charge flow.
The RNA World as a Model System to Study the Origin of Life.
Pressman, Abe; Blanco, Celia; Chen, Irene A
2015-10-05
Understanding how life arose is a fundamental problem of biology. Much progress has been made by adopting a synthetic and mechanistic perspective on originating life. We present a current view of the biochemistry of the origin of life, focusing on issues surrounding the emergence of an RNA World in which RNA dominated informational and functional roles. There is cause for optimism on this difficult problem: the prebiotic chemical inventory may not have been as nightmarishly complex as previously thought; the catalytic repertoire of ribozymes continues to expand, approaching the goal of self-replicating RNA; encapsulation in protocells provides evolutionary and biophysical advantages. Nevertheless, major issues remain unsolved, such as the origin of a genetic code. Attention to this field is particularly timely given the accelerating discovery and characterization of exoplanets.
Seiler, Ralf
well as seasonal distribution of the annual rainfall in the catchment areas and the resulting water supply contributed by the river system. Due to the relatively good availability of (surface) water, the Niger Inland Ecosystem serves as stop-over for many migrating birds and other wildlife species as well as an eonomic base for farmers and pastoral people. As a consequence, the entire Niger Inland Delta has been declared as protected RAMSAR site in 2004. Interaction among pre-flood, flood and post-flood conditions strongly affect the patterns of landcover in and around the delta as vegetation cover is strongly correlated with the availability of surface water. The Inland Delta is dominantly covered by (irrigated) fields or grasslands during flood and post-flood periods (October to January), while most of the photosynthetically active vegetation withers during the rest of the year. This yields in highly vibrant vegetation cover, although the vegetation cover density remains low even during flood period for most of the Inland Delta. This study analyses the intra-annual dynamics as well as changes in vegetation cover between individual years by interpreting 17 MERIS full resolution data over the period from Aug. 2002 to June 2005. MERIS sensor provides measurements from 15 spectral bands within the VIS and NIR part of the EMS with 300 m spatial resolution. Thus allowing for analyses at a regional scale level with high sensitivity for the amount of green vegetation. Short time dynamics of vegetation are related to changes in vegetation cover density. These changes were modelled with Vegetation Indices (VI) as parameter. To overcome well known problems related with NDVIs dependence of illumination and viewing angle, background signal (soil brightness) and changes in humidity, the MGVI was used as indix to derive more sophisticated biophysical information in addition to the classical NDVI. Soil types influence the remotely sensed signal significantly due to the overall
Katakamsetty, Ushasree; Chee, Jiansheng Jansen; Li, Yongfu; Hui, Chiu Wing; Huang, Yaodong; de la Garza, Ernesto Gene
2017-03-01
As process technology scales down, the number of Chemical Mechanical Polishing (CMP) processes and steps used in chip manufacturing are increasing exponentially. Shrinking process margins increase the risk of excessive metal or oxide thickness or topography variations, causing potential yield problems such as dishing, erosion, resist lifting or printability issues. Present DFM CMP modeling and applications mainly focus on the hotspot detection and fixing methodology for the Back-End-Of-Line (BEOL) layers [1]. Today, the present methodology is no longer sufficient to eliminate all the CMP related manufacturing defects. There is a strong demand f